Anti-corrosion coating for ocean buoy and preparation method of anti-corrosion coating

Abstract

The invention discloses an anticorrosive paint for ocean buoys and a preparation method of the anticorrosive paint, and relates to the technical field of paints.The anticorrosive paint is composed of a component A and a component B, the component A is prepared from the following components in parts by weight: 40-70 parts of waterborne epoxy resin, 5-20 parts of zinc powder, 6-18 parts of modified graphene oxide, 0.1-1 part of a silane coupling agent, 1-3 parts of a dispersing agent, 0.1-1 part of a defoaming agent, 1-4 parts of a corrosion inhibitor, 0.1-1 part of a flatting agent, 0.1-1 part of an anti-settling agent and 0.2-0.8 part of a thickening agent; the component B is prepared from the following components in parts by weight: 30-45 parts of a curing agent and 30-50 parts of water; aiming at the severe working condition of the ocean buoy, a three-in-one synergistic anti-corrosion system of physical blocking, electrochemical protection and surface dewatering is constructed, and excellent long-acting protection in the ocean environment is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of coating technology, and in particular to an anti-corrosion coating for marine buoys and a preparation method thereof. BACKGROUND

[0002] As an important marine observation equipment, marine buoys are exposed to harsh marine environments with high salt content and high humidity for a long time, and are subject to serious corrosion threats. Seawater contains a large amount of corrosive media such as chloride ions and sulfate ions, combined with the complex effects of salt spray corrosion of marine atmosphere, tidal scouring and marine biofilm attachment, which makes the metal structure of the buoy prone to electrochemical corrosion, seriously affecting its service life and reliability.

[0003] Currently, marine buoy corrosion protection mainly adopts coating protection. Traditional anti-corrosion coatings are mainly organic solvent-based epoxy coatings and polyurethane coatings, which have certain anti-corrosion effect, but have the following problems: first, the single physical barrier mechanism is prone to protection failure due to coating defects; second, the use of organic solvents brings environmental pollution and safety hazards; third, under the long-term action of marine environment, the coating is prone to aging and cracking, and the anti-corrosion life is limited.

[0004] To improve the corrosion resistance, researchers began to add metal powders such as zinc powder to the coating, and used the sacrificial anode principle to provide electrochemical protection. For example, Chinese patent CN109608994A discloses a graphene anti-corrosion coating applied to marine equipment, which is composed of two components A and B. Component A is composed of the following raw materials in parts by weight: liquid epoxy resin: 15-25 parts, active diluent: 3-5 parts, zinc powder: 60-70 parts, dispersant: 0.3-1.0 parts, defoamer: 0.1-1.0 parts, adhesion promoter: 0.3-0.6 parts, anti-settling and anti-sagging aid: 0.2-2.0 parts, mica powder: 2-10 parts, graphene slurry: 3-10 parts; component B is a curing agent component; although the coating enhances the electrochemical corrosion resistance, the zinc powder is prone to sedimentation and agglomeration in the coating system, has poor dispersion stability, and the electrochemical protection relying solely on zinc powder is still insufficient in complex marine environments.

[0005] In recent years, graphene materials have attracted attention in the field of anticorrosive coatings due to their unique two-dimensional layered structure and excellent barrier properties. Graphene oxide, as an important derivative of graphene, contains abundant oxygen-containing functional groups, has good dispersibility and modifiability. Chinese patent CN117126579A reports a graphene marine anticorrosive coating, which is composed of waterborne epoxy resin, Fe3O4@TiO2 nanoparticles with core-shell structure, graphene oxide, additives, curing agent, nano-scaled flaky zinc powder and water; the layered structure of graphene oxide can effectively prolong the penetration path of corrosion medium and improve the barrier properties of the coating. However, the original graphene oxide is prone to agglomeration in the coating system and lacks effective bonding with the matrix, limiting the full play of its anticorrosive effect.

[0006] Research on the modification of graphene oxide has also gradually expanded. However, existing methods for modifying graphene oxide are mostly single, fail to fully exert the synergistic effect of multiple functional groups, and the application research in marine buoy dedicated anticorrosive coatings is relatively less.

[0007] Therefore, it is of great significance to develop a multi-mechanism synergistic anticorrosive coating combining physical barrier, electrochemical protection and surface functionalization for improving the anticorrosive performance and service life of marine buoys. SUMMARY

[0008] In order to solve the problems existing in the prior art, the purpose of the present application is to provide an anticorrosive coating for marine buoys and a preparation method thereof, and the present application constructs a three-in-one synergistic anticorrosive system of "physical barrier-electrochemical protection-surface hydrophobicity". The multi-dimensional reinforcing effect of modified graphene oxide and zinc powder significantly improves the compactness and salt spray resistance of the coating, effectively blocks the penetration of corrosion medium, solves the problem of easy failure of traditional coatings, realizes long-term protection of marine buoys, and is also suitable for anticorrosive protection of marine engineering structures such as ships, offshore platforms and port facilities.

[0009] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows: An anticorrosive coating for marine buoys is composed of component A and component B, wherein the component A is made of the following components in parts by weight: waterborne epoxy resin 40-70 parts, zinc powder 5-20 parts, modified graphene oxide 6-18 parts, silane coupling agent 0.1-1 part, dispersing agent 1-3 parts, defoaming agent 0.1-1 part, corrosion inhibitor 1-4 parts, leveling agent 0.1-1 part, anti-settling agent 0.1-1 part, and thickening agent 0.2-0.8 part; the component B is made of the following components: curing agent 30-45 parts and water 30-50 parts.

[0010] Preferably, the modified graphene oxide is prepared by the following method steps: (1) dispersing graphene oxide into Tris buffer solution, uniformly ultrasonic dispersing, then adding dopamine hydrochloride, stirring reaction, centrifuging, washing and drying the product to obtain pretreated graphene oxide; Dopamine biomimetic polymerization modification: in the weak alkaline Tris buffer solution environment, dopamine hydrochloride molecules first insert into the interlayer gap of graphene oxide through hydrogen bond interaction and π-π stacking effect, effectively weakening the van der Waals force between the layers, promoting the exfoliation and dispersion of graphene oxide. Subsequently, dopamine undergoes self-oxidation polymerization to form polydopamine (PDA) polymer chains. The polydopamine molecules uniformly coat the surface of the exfoliated graphene oxide layers, providing steric hindrance effect to prevent re-agglomeration, and at the same time forming a functional coating with good biocompatibility, providing active sites for subsequent polyaniline grafting.

[0011] Preferably, in step (1), the amount ratio of graphene oxide, Tris buffer solution, dopamine hydrochloride is 1g: 100-300mL: 0.5-2g; the concentration of Tris buffer solution is 10-50mmol / L, and pH is 8-9.

[0012] Preferably, in step (1), the ultrasonic treatment is 30-60min; the stirring reaction condition is stirring at 20-35℃ for 12-24h.

[0013] (2) dispersing pretreated graphene oxide into hydrochloric acid solution, adding aniline monomer under ice bath nitrogen atmosphere, stirring to adsorb and balance, then slowly dropping ammonium persulfate aqueous solution, stirring reaction, filtering, washing and drying the product to obtain intercalated graphene oxide; In-situ polyaniline intercalation polymerization: in a strong acid environment, aniline monomers first pre-adsorb in the interlayer gap of graphene oxide through π-π interaction, then ammonium persulfate as an initiator slowly releases sulfate free radicals at low temperature to oxidize aniline monomers to form cationic free radicals. These active intermediates undergo chain polymerization reaction to grow in-situ in the interlayer of graphene oxide to form doped polyaniline chains, and chloride ions as dopants make polyaniline maintain conductive state, finally constructing a conductive composite material with layered intercalation structure.

[0014] Preferably, in step (2), the amount ratio of pretreated graphene oxide, hydrochloric acid solution, aniline, ammonium persulfate aqueous solution is 1g: 100-200mL: 1-2.5mL: 20-50mL; 20-50mL of ammonium persulfate aqueous solution contains 2.5-6g of ammonium persulfate.

[0015] Preferably, in step (2), the ice bath condition is 0-5℃; the stirring reaction condition is stirring at 0-5℃ for 6-12h.

[0016] (3) The intercalated graphene oxide was dehydrated and then dispersed in DMF. Glycidyl 2,2,3,3-tetrafluoropropyl ether and triethylamine were added. The mixture was heated and refluxed under a nitrogen atmosphere. The product was filtered, washed and dried to obtain modified graphene oxide.

[0017] Chemical grafting modification of epoxy groups: In anhydrous organic solvents, triethylamine acts as a basic catalyst to activate various amino groups on the surface of the composite material, including amino groups on the polyaniline backbone and in the polydopamine coating. These active sites then perform a cooperative nucleophilic attack on the epoxy groups in the glycidyl 2,2,3,3-tetrafluoropropyl ether molecule. An epoxy ring-opening reaction occurs via an SN2 mechanism, where amino groups from different sources form stable CN covalent bonds with the epoxy groups, constructing a multi-layered network of fluorinated alkyl segments on the material surface.

[0018] Preferably, in step (3), the ratio of intercalated graphene oxide, DMF, and glycidyl 2,2,3,3-tetrafluoropropyl ether is 1g:50~100mL:0.1~0.3mL.

[0019] Preferably, in step (3), the intercalated graphene oxide is vacuum dried at 60°C for 4 hours to strictly remove water; the reflux reaction conditions are reflux reaction at 80~100°C for 12~24 hours.

[0020] This invention also claims a method for preparing the aforementioned anti-corrosion coating for marine buoys, comprising the following steps: preheating waterborne epoxy resin to 40-50°C, adjusting the pH of the system to 8-9, adding zinc powder, modified graphene oxide, silane coupling agent, and dispersant, raising the temperature to 60-70°C and stirring for 1-3 hours, cooling to room temperature, adding defoamer, corrosion inhibitor, leveling agent, anti-settling agent, and thickener, stirring evenly, and filtering to obtain component A; mixing the curing agent with water and ultrasonically treating for 20-40 minutes to obtain component B.

[0021] The present invention also claims a method of using the aforementioned anti-corrosion coating for marine buoys, comprising the following steps: mixing component A and component B evenly, spraying the coating onto the area to be coated 3 to 5 times, and baking for curing.

[0022] Compared with the prior art, the present invention has the following beneficial effects: 1. The anti-corrosion coating of this invention achieves excellent anti-corrosion performance in marine environments through the synergistic effect of its components. Waterborne epoxy resin, as the matrix resin, provides excellent film-forming properties, adhesion, and chemical corrosion resistance; zinc powder, as a sacrificial anode material, provides long-lasting electrochemical anti-corrosion protection for the substrate; modified graphene oxide, with its unique layered structure, constructs a dense physical barrier layer, effectively preventing the penetration of corrosive media, while its conductivity forms a synergistic anti-corrosion system with zinc powder; the two-dimensional nanosheets of modified graphene oxide form a continuous labyrinthine protective barrier during the coating curing process, forcing corrosive media to penetrate along the surface of the sheets, significantly extending the diffusion path of harmful substances such as moisture, oxygen, and chloride ions, and greatly reducing their probability of reaching the metal substrate; silane coupling agent significantly enhances the interfacial bonding force of each phase through chemical bonding; corrosion inhibitor further inhibits the electrochemical reaction of metal ions; dispersants, leveling agents, anti-settling agents, and other additives ensure good application performance and storage stability of the coating. The organic combination of multiple protective mechanisms enables the coating to exhibit excellent long-term anti-corrosion capabilities in harsh marine environments.

[0023] 2. This invention provides a modified graphene oxide that exhibits different synergistic effects through a three-step functionalization modification. The first step introduces a polydopamine coating, which not only significantly improves the dispersibility and biocompatibility of graphene oxide, but its abundant hydroxyl and amino groups also provide active reaction sites for subsequent modification. The second step, in-situ intercalation polymerization, introduces polyaniline chains that form a stable bond with the graphene sheets through π-π interactions, effectively preventing the sheets from re-stacking and agglomerating, ensuring that the graphene oxide remains highly dispersed in the epoxy matrix. Simultaneously, the chemical bonding between the polyaniline chains and epoxy resin molecules further enhances the interfacial bonding strength. Polyaniline imparts excellent electrical conductivity to the material, and the resulting doped structure remains stable in acidic environments, synergistically constructing an electrochemical anti-corrosion network with zinc powder. Furthermore, the conjugated structure of polyaniline enhances the material's mechanical strength and thermal stability. The third step, grafting fluorinated alkyl segments, significantly reduces the surface free energy of the coating, giving it excellent hydrophobicity and anti-fouling properties, effectively reducing marine organism attachment and dirt accumulation. The synergistic effect of multiple functional groups enables modified graphene oxide to simultaneously possess excellent dispersion stability, electrical conductivity and corrosion resistance, and surface hydrophobicity. The strong interfacial bonding provided by polydopamine, the conductive network constructed by polyaniline, and the low-energy surface formed by fluorine-containing groups work together to construct a multi-level corrosion protection system in the epoxy matrix that combines physical barrier, electrochemical protection, and self-cleaning functions. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. Of course, the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention.

[0025] Unless otherwise specified, all chemical reagents and materials in this invention are purchased from the market or synthesized from raw materials purchased from the market.

[0026] The waterborne epoxy resin is type E51 waterborne epoxy resin; The zinc powder is 800 mesh zinc powder; Graphene oxide particle size distribution D 10 ~D 90 The thickness ranges from 5 to 30 μm, with a median thickness of 10 nm to 40 nm. The dispersant model is BYK-333; The defoamer is TEGO Foamex 825. The leveling agent is EFKA-3777; The anti-settling agent is aluminum stearate; The curing agent is a polyetheramine curing agent, model D400.

[0027] A method for preparing an anti-corrosion coating for marine buoys includes the following steps: (1) Disperse 1g of graphene oxide in 100~300mL of 10~50mmol / L Tris buffer (pH=8~9), sonicate for 30~60min, then add 0.5~2g of dopamine hydrochloride, stir and react at 20~35℃ for 12~24h, centrifuge, wash and dry the product to obtain pretreated graphene oxide; (2) Disperse 1g of pretreated graphene oxide into 100-200mL of hydrochloric acid solution, add 1-2.5mL of aniline monomer under a nitrogen atmosphere at 0-5℃ in an ice bath, stir to make it adsorption equilibrium, and then slowly drop in 20-50mL of ammonium persulfate aqueous solution containing 2.5-6g of ammonium persulfate. Stir the reaction at 0-5℃ for 6-12h, filter, wash and dry the product to obtain intercalated graphene oxide; (3) 1g of intercalated graphene oxide was vacuum dried at 60℃ for 4h to strictly remove water, and then dispersed in 50~100mL DMF. 0.1~0.3mL of glycidyl 2,2,3,3-tetrafluoropropyl ether and triethylamine were added, and the mixture was refluxed at 80~100℃ under nitrogen atmosphere for 12~24h. The product was filtered, washed and dried to obtain modified graphene oxide. (4) Preheat 40-70 parts of waterborne epoxy resin to 40-50℃, adjust the pH of the system to 8-9, add 5-20 parts of zinc powder, 6-18 parts of modified graphene oxide, 0.1-1 parts of silane coupling agent, and 1-3 parts of dispersant, heat to 60-70℃ and continue stirring for 1-3 hours, cool to room temperature, add 0.1-1 parts of defoamer, 1-4 parts of corrosion inhibitor, 0.1-1 parts of leveling agent, 0.1-1 parts of anti-settling agent, and 0.2-0.8 parts of thickener, stir evenly, and filter to obtain component A; mix 30-45 parts of curing agent with 30-50 parts of water, and sonicate for 20-40 minutes to obtain component B.

[0028] The present invention will be further described below through specific embodiments.

[0029] Example 1 A method for preparing an anti-corrosion coating for marine buoys includes the following steps: (1) 1g of graphene oxide was dispersed in 200mL of 30mmol / L Tris buffer (pH=8.5), ultrasonically dispersed for 45min, and then 2g of dopamine hydrochloride was added. The mixture was stirred at 35℃ for 12h. The product was centrifuged, washed and dried to obtain pretreated graphene oxide. (2) Disperse 1g of pretreated graphene oxide into 150mL of hydrochloric acid solution, add 2.5mL of aniline monomer under a nitrogen atmosphere at 2℃ in an ice bath, stir to make it adsorption equilibrium, and then slowly drop 50mL of ammonium persulfate aqueous solution containing 6g of ammonium persulfate. Stir the reaction at 3℃ for 6h, filter, wash and dry the product to obtain intercalated graphene oxide. (3) 1g of intercalated graphene oxide was vacuum dried at 60℃ for 4h to strictly remove water, and then dispersed in 80mL DMF. 0.3mL of glycidyl 2,2,3,3-tetrafluoropropyl ether and triethylamine were added, and the mixture was refluxed at 100℃ under nitrogen atmosphere for 12h. The product was filtered, washed and dried to obtain modified graphene oxide. (4) Preheat 7000g of waterborne epoxy resin to 45℃, adjust the pH of the system to 8.5, add 2000g of zinc powder, 1800g of modified graphene oxide, 100g of silane coupling agent KH560 and 300g of dispersant, heat to 65℃ and continue stirring for 2h, cool to room temperature, add 100g of defoamer, 400g of phosphate corrosion inhibitor, 100g of leveling agent, 100g of anti-settling agent and 80g of thickener carboxymethyl cellulose, stir evenly, filter to obtain component A; mix 4500g of curing agent polyetheramine with 5000g of water, sonicate for 30min to obtain component B.

[0030] Example 2 A method for preparing an anti-corrosion coating for marine buoys includes the following steps: (1) 1g of graphene oxide was dispersed in 200mL of 30mmol / L Tris buffer (pH=8.5), ultrasonically dispersed for 45min, and then 1.5g of dopamine hydrochloride was added. The mixture was stirred at 30℃ for 16h. The product was centrifuged, washed and dried to obtain pretreated graphene oxide. (2) Disperse 1g of pretreated graphene oxide into 150mL of hydrochloric acid solution, add 2.0mL of aniline monomer under a nitrogen atmosphere at 2℃ in an ice bath, stir to make it adsorption equilibrium, and then slowly drop 40mL of ammonium persulfate aqueous solution containing 5g of ammonium persulfate. Stir the reaction at 3℃ for 8h, filter, wash and dry the product to obtain intercalated graphene oxide. (3) 1g of intercalated graphene oxide was vacuum dried at 60℃ for 4h to strictly remove water, and then dispersed in 80mL DMF. 0.2mL of glycidyl 2,2,3,3-tetrafluoropropyl ether and triethylamine were added, and the mixture was refluxed at 95℃ under nitrogen atmosphere for 16h. The product was filtered, washed and dried to obtain modified graphene oxide. (4) Preheat 6000g of waterborne epoxy resin to 45℃, adjust the pH of the system to 8.5, add 1500g of zinc powder, 1400g of modified graphene oxide, 70g of silane coupling agent KH560 and 250g of dispersant, heat to 65℃ and continue stirring for 2h, cool to room temperature, add 70g of defoamer, 300g of phosphate corrosion inhibitor, 70g of leveling agent, 70g of aluminum stearate anti-settling agent and 60g of thickener carboxymethyl cellulose, stir evenly, filter to obtain component A; mix 4000g of curing agent polyetheramine with 4500g of water, sonicate for 30min to obtain component B.

[0031] Example 3 A method for preparing an anti-corrosion coating for marine buoys includes the following steps: (1) 1g of graphene oxide was dispersed in 200mL of 30mmol / L Tris buffer (pH=8.5), ultrasonically dispersed for 45min, and then 1g of dopamine hydrochloride was added. The mixture was stirred at 25℃ for 20h. The product was centrifuged, washed and dried to obtain pretreated graphene oxide. (2) Disperse 1g of pretreated graphene oxide into 150mL of hydrochloric acid solution, add 1.5mL of aniline monomer under a nitrogen atmosphere at 2℃ in an ice bath, stir to make it adsorption equilibrium, and then slowly drop 30mL of ammonium persulfate aqueous solution containing 4g of ammonium persulfate. Stir the reaction at 3℃ for 8h, filter, wash and dry the product to obtain intercalated graphene oxide. (3) 1g of intercalated graphene oxide was vacuum dried at 60℃ for 4h to strictly remove water, and then dispersed in 80mL DMF. 0.2mL of glycidyl 2,2,3,3-tetrafluoropropyl ether and triethylamine were added, and the mixture was refluxed at 85℃ under nitrogen atmosphere for 16h. The product was filtered, washed and dried to obtain modified graphene oxide. (4) Preheat 5000g of waterborne epoxy resin to 45℃, adjust the pH of the system to 8.5, add 1000g of zinc powder, 1000g of modified graphene oxide, 40g of silane coupling agent KH560 and 150g of dispersant, heat to 65℃ and continue stirring for 2h, cool to room temperature, add 40g of defoamer, 200g of phosphate corrosion inhibitor, 40g of leveling agent, 40g of aluminum stearate anti-settling agent and 40g of thickener carboxymethyl cellulose, stir evenly, filter to obtain component A; mix 3500g of curing agent polyetheramine with 3500g of water, sonicate for 30min to obtain component B.

[0032] Example 4 A method for preparing an anti-corrosion coating for marine buoys includes the following steps: (1) 1g of graphene oxide was dispersed in 200mL of 30mmol / L Tris buffer (pH=8.5), ultrasonically dispersed for 45min, and then 0.5g of dopamine hydrochloride was added. The mixture was stirred at 20℃ for 24h. The product was centrifuged, washed and dried to obtain pretreated graphene oxide. (2) Disperse 1g of pretreated graphene oxide into 150mL of hydrochloric acid solution, add 1mL of aniline monomer under a nitrogen atmosphere at 2℃ in an ice bath, stir to make it adsorption equilibrium, and then slowly drop 20mL of ammonium persulfate aqueous solution containing 2.5g of ammonium persulfate. Stir the reaction at 3℃ for 12h, filter, wash and dry the product to obtain intercalated graphene oxide. (3) 1g of intercalated graphene oxide was vacuum dried at 60℃ for 4h to strictly remove water, and then dispersed in 80mL DMF. 0.1mL of glycidyl 2,2,3,3-tetrafluoropropyl ether and triethylamine were added, and the mixture was refluxed at 80℃ under nitrogen atmosphere for 24h. The product was filtered, washed and dried to obtain modified graphene oxide. (4) Preheat 4000g of waterborne epoxy resin to 45℃, adjust the pH of the system to 8.5, add 500g of zinc powder, 600g of modified graphene oxide, 10g of silane coupling agent KH560, and 100g of dispersant, heat to 65℃ and continue stirring for 2h, cool to room temperature, add 10g of defoamer, 100g of phosphate corrosion inhibitor, 10g of leveling agent, 10g of aluminum stearate anti-settling agent, and 20g of thickener carboxymethyl cellulose, stir evenly, and filter to obtain component A; mix 3000g of curing agent polyetheramine with 3000g of water, and sonicate for 30min to obtain component B.

[0033] Comparative Example 1 A method for preparing an anti-corrosion coating for marine buoys includes the following steps: (1) 1g of graphene oxide was dispersed in 200mL of 30mmol / L Tris buffer (pH=8.5), ultrasonically dispersed for 45min, and then 2g of dopamine hydrochloride was added. The mixture was stirred at 35℃ for 12h. The product was centrifuged, washed and dried to obtain pretreated graphene oxide. (2) Disperse 1g of pretreated graphene oxide into 150mL of hydrochloric acid solution, add 2.5mL of aniline monomer under a nitrogen atmosphere at 2℃ in an ice bath, stir to make it adsorption equilibrium, and then slowly drop 50mL of ammonium persulfate aqueous solution containing 6g of ammonium persulfate. Stir the reaction at 3℃ for 6h, filter, wash and dry the product to obtain intercalated graphene oxide. (3) Preheat 7000g of waterborne epoxy resin to 45℃, adjust the pH of the system to 8.5, add 2000g of zinc powder, 1600g of intercalated graphene oxide, 200g of glycidyl 2,2,3,3-tetrafluoropropyl ether, 100g of silane coupling agent KH560, and 300g of dispersant, heat to 65℃ and continue stirring for 2h, cool to room temperature, add 100g of defoamer, 400g of phosphate corrosion inhibitor, 100g of leveling agent, 100g of aluminum stearate anti-settling agent, and 80g of thickener carboxymethyl cellulose, stir evenly, and filter to obtain component A; mix 4500g of curing agent polyetheramine with 5000g of water, and sonicate for 30min to obtain component B.

[0034] Comparative Example 2 A method for preparing an anti-corrosion coating for marine buoys includes the following steps: (1) 1g of graphene oxide was dispersed in 200mL of 30mmol / L Tris buffer (pH=8.5), ultrasonically dispersed for 45min, and then 2g of dopamine hydrochloride was added. The mixture was stirred at 35℃ for 12h. The product was centrifuged, washed and dried to obtain pretreated graphene oxide. (2) Preheat 7000g of waterborne epoxy resin to 45℃, adjust the pH of the system to 8.5, add 2000g of zinc powder, 1600g of pretreated graphene oxide, 200g of aniline, 100g of silane coupling agent KH560 and 300g of dispersant, heat to 65℃ and continue stirring for 2h, cool to room temperature, add 100g of defoamer, 400g of phosphate corrosion inhibitor, 100g of leveling agent, 100g of aluminum stearate anti-settling agent and 80g of thickener carboxymethyl cellulose, stir evenly, filter to obtain component A; mix 4500g of curing agent polyetheramine with 5000g of water, sonicate for 30min to obtain component B.

[0035] Comparative Example 3 A method for preparing an anti-corrosion coating for marine buoys includes the following steps: Preheat 7000 g of waterborne epoxy resin to 45 °C, adjust the pH of the system to 8.5, add 2000 g of zinc powder, 1600 g of graphene oxide, 200 g of dopamine hydrochloride, 100 g of silane coupling agent KH560, and 300 g of dispersant. Raise the temperature to 65 °C and continue stirring for 2 h. Then cool it to room temperature, add 100 g of defoamer, 400 g of phosphate corrosion inhibitor, 100 g of leveling agent, 100 g of aluminum stearate anti-settling agent, and 80 g of thickener carboxymethyl cellulose. Stir evenly and filter to obtain Component A; Mix 4500 g of curing agent polyetheramine with 5000 g of water and perform ultrasonic treatment for 30 min to obtain Component B.

[0036] Perform performance tests on the anti-corrosion coatings prepared in Examples 1-4 and Comparative Examples 1-3. Sand the galvanized sheet with 800-mesh sandpaper to remove the surface substances, and then wipe it repeatedly with alcohol to remove the surface oil. Mix Component A and Component B of the coating evenly, spray it 4 times on the area to be coated to form a coating with a thickness of about 100 µm, bake and cure it at 75 °C for 30 min, and maintain it at room temperature for 7 d. Then seal the edges with paraffin, draw a series of parallel horizontal and vertical lines with a knife. The horizontal and vertical lines intersect to form small squares. Stick the tape on the scratched area and slowly tear it off to observe whether the film layer peels off to judge its adhesion. Analyze the adhesion grade according to the standard of GB / T 9286-2021 "Paints and varnishes - Cross-cut test". Use an optical goniometer to measure the hydrophilic / hydrophobic properties of the sample surface, and the contact angle value is the average of the same sample at 5 different positions.

[0037] Conduct salt spray tests on the coatings according to ASTM B117. Use 3.5 wt% NaCl solution to simulate the seawater environment and evaluate the corrosion resistance of the coatings in the simulated marine atmospheric environment. The coating samples are placed in a dedicated salt spray test chamber and continuously exposed to high salinity conditions. The test time is 1000 h to simulate the influence of long-term marine climate. The coating samples include those with and without surface scribing.

[0038] Test the acid resistance according to the standard of GB 9274-1988 "Paints and varnishes - Determination of resistance to liquid media", the test environment is 50% H2SO4, and the test time is 168 h; Test the solvent resistance according to the standard of GB 9274-1988, the test environment is acetone, and the test time is 168 h; Test the alkali resistance according to the standard of GB 9274-1988, the test environment is 30% NaOH, and the test time is 168 h. If the coating shows no blistering, cracking, peeling, or color change (rusting) after the test, it is considered qualified; otherwise, it is considered unqualified. The specific test results are shown in Table 1.

[0039] Table 1 Performance test results of anti-corrosion coatings The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. An anticorrosive coating for a marine buoy, which is composed of a component A and a component B, characterized in that, The component A is made of the following components in parts by weight: water-based epoxy resin 40-70 parts, zinc powder 5-20 parts, modified graphene oxide 6-18 parts, silane coupling agent 0.1-1 part, dispersing agent 1-3 parts, defoaming agent 0.1-1 part, corrosion inhibitor 1-4 parts, leveling agent 0.1-1 part, anti-settling agent 0.1-1 part, thickening agent 0.2-0.8 part; the component B is made of the following components: curing agent 30-45 parts, water 30-50 parts.

2. The anticorrosive paint for marine buoy according to claim 1, characterized by, The modified graphene oxide is prepared by the following steps: (1) dispersing graphene oxide into Tris buffer solution, uniformly ultrasonic dispersing, then adding dopamine hydrochloride, stirring to react, centrifuging, washing and drying the product to obtain pretreated graphene oxide; (2) dispersing the pretreated graphene oxide into hydrochloric acid solution, adding aniline monomer under ice bath and nitrogen atmosphere, stirring to adsorb and balance, then slowly dropping ammonium persulfate aqueous solution, stirring to react, filtering, washing and drying the product to obtain intercalated graphene oxide; (3) removing water from the intercalated graphene oxide, then dispersing into DMF, adding glycidyl 2,2,3,3-tetrafluoropropyl ether and triethylamine, heating to reflux under nitrogen atmosphere to react, filtering, washing and drying the product to obtain modified graphene oxide.

3. The anticorrosive coating for a marine buoy according to claim 2, characterized by, In step (1), the amount ratio of graphene oxide, Tris buffer solution, dopamine hydrochloride is 1g: 100-300mL: 0.5-2g; the concentration of Tris buffer solution is 10-50mmol / L, pH=8-9.

4. The anticorrosive paint for marine buoy according to claim 2, characterized by, In step (1), the ultrasonic treatment is 30-60min; the stirring reaction condition is 20-35℃ for 12-24h.

5. The anticorrosive paint for marine buoy according to claim 2, characterized by, In step (2), the amount ratio of pretreated graphene oxide, hydrochloric acid solution, aniline, ammonium persulfate aqueous solution is 1g: 100-200mL: 1-2.5mL: 20-50mL; 20-50mL ammonium persulfate aqueous solution contains 2.5-6g ammonium persulfate.

6. The anticorrosive paint for marine buoy according to claim 2, characterized by In step (2), the ice bath condition is 0-5℃; the stirring reaction condition is 0-5℃ for 6-12h.

7. The anticorrosive paint for marine buoy according to claim 2, characterized by In step (3), the amount ratio of intercalated graphene oxide, DMF, glycidyl 2,2,3,3-tetrafluoropropyl ether is 1g: 50-100mL: 0.1-0.3mL.

8. The anticorrosive paint for marine buoy according to claim 2, characterized by, In step (3), the intercalated graphene oxide is dried at 60℃ under vacuum for 4h to strictly remove water; the reflux reaction condition is 80-100℃ for 12-24h.

9. A method of preparing an anticorrosive coating for marine buoys according to any one of claims 1 to 8, characterized in that, The method comprises the following steps: preheating the water-based epoxy resin to 40-50℃, adjusting the pH of the system to 8-9, adding zinc powder, modified graphene oxide, silane coupling agent and dispersing agent, heating to 60-70℃ and continuing to stir for 1-3h, reducing to room temperature, adding defoaming agent, corrosion inhibitor, leveling agent, anti-settling agent and thickening agent, stirring uniformly, and filtering to obtain component A; mixing the curing agent with water, and ultrasonic treating for 20-40min to obtain component B.

10. A method of using the anticorrosive coating for marine buoys according to any one of claims 1 to 8, characterized in that, The method comprises the following steps: mixing component A and component B uniformly, spraying 3-5 times to the area to be coated, and baking and curing.

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