Metal anticorrosive paint based on modified graphene and preparation method thereof

Abstract

The invention relates to the field of paint, in particular to metal anti-corrosion paint based on modified graphene and a preparation method of the metal anti-corrosion paint. The metal anticorrosive paint based on the modified graphene is prepared from the following raw materials: waterborne epoxy resin, fluorocarbon resin, the modified graphene, a compound functional agent, a dispersing agent, a flatting agent, a defoaming agent, an anti-settling agent and the like. The finally prepared metal anticorrosive paint containing modified graphene not only has excellent wear resistance, thermal stability and the like, but also can greatly improve the dispersity and compatibility of the modified graphene material in the system, and effectively avoids the phenomena of precipitation, phase splitting and mass agglomeration of the graphene material in the anticorrosive paint system; and the long-term corrosion resistance and mechanical properties of the coating are further balanced.

Description

Technical Field

[0001] The present application relates to the field of coatings, and more specifically, to a metal anti-corrosion coating based on modified graphene and a preparation method thereof. Background Art

[0002] With the development of modern industry, the problem of metal corrosion has become increasingly serious, causing huge losses to the economy and the environment. Therefore, the development of efficient and environmentally friendly anti-corrosion coatings has become an important research direction in the field of materials science. In recent years, as a new type of two-dimensional nanomaterial, graphene has shown great application potential in anti-corrosion coatings due to its excellent physical and chemical properties, such as excellent electrical conductivity, thermal stability, and extremely high mechanical strength.

[0003] Graphene is a planar film composed of carbon atoms with sp 2 hybrid orbitals forming a hexagonal honeycomb lattice, a two-dimensional material with only one carbon atom thickness. Its unique electronic structure endows it with extraordinary electrical properties; while the strong σ bonds and large specific surface area make graphene have excellent mechanical properties and barrier properties. However, due to the surface inertness and difficult dispersion of pure graphene, its direct application in anti-corrosion coatings is limited. The application of modified graphene in coatings is mainly achieved by forming complexes with other substances.

[0004] Although the metal anti-corrosion coatings based on modified graphene have shown good application prospects in recent years, there are still some technical problems in the current research and technology in this field. For example, the compatibility and instability problems of modified graphene in the system lead to phenomena such as precipitation, phase separation, and a large amount of aggregation in the application of anti-corrosion coatings, directly affecting the performance of the finally formed anti-corrosion coatings; and in long-term applications, it is difficult to balance the long-term anti-corrosion performance and mechanical performance of the metal anti-corrosion coatings added with modified graphene. The addition of too much modified graphene easily causes an increase in the brittleness of the coating, reducing flexibility and peel strength; finally, there is also poor comprehensive performance, and the actual application effect of modified graphene is less than satisfactory, especially in terms of weather resistance and water resistance. Summary of the Invention

[0005] Therefore, in order to effectively solve the above existing problems, the present application provides a metal anti-corrosion coating based on modified graphene and a preparation method thereof. The finally prepared metal anti-corrosion coating containing modified graphene not only has excellent wear resistance, thermal stability and other properties, but also can greatly improve the dispersion and compatibility of the modified graphene material in the system, effectively avoiding the precipitation, phase separation and a large amount of aggregation phenomena of the graphene material in the anti-corrosion coating system, and further balancing the long-term anti-corrosion property and mechanical performance of the coating, being able to combine good flexibility and peel strength while effectively preventing corrosion, and also comprehensively improving the weather resistance and water resistance of the coating.

[0006] The metal anti-corrosion coating based on modified graphene, calculated by mass parts, consists of the following raw materials: 50 - 70 parts of waterborne epoxy resin, 10 - 20 parts of fluorocarbon resin, 3 - 5 parts of modified graphene, 8 - 15 parts of compound functional agent, 0.5 - 2 parts of dispersant, 0.3 - 1 part of leveling agent, 0.2 - 0.8 part of defoaming agent, 1.5 - 2.5 parts of anti-settling agent, 0.3 - 1.2 parts of wetting agent, 1 - 3 parts of corrosion inhibitor, and 15 - 30 parts of solvent.

[0007] As a preferred embodiment, the mass ratio of the waterborne epoxy resin, fluorocarbon resin and modified graphene is (55 - 65):(15 - 20):(3 - 4.5).

[0008] As a preferred embodiment, the mass ratio of the waterborne epoxy resin, fluorocarbon resin and modified graphene is (58 - 62):(16 - 18):(3 - 3.2).

[0009] As a preferred embodiment, the mass ratio of the waterborne epoxy resin and compound functional agent is (58 - 62):(10 - 14).

[0010] As a preferred embodiment, the waterborne epoxy resin is bisphenol A epoxy resin.

[0011] As a preferred embodiment, the epoxy equivalent of the waterborne epoxy resin is 185 - 192 g / eq, and the viscosity is 10000 - 15000 mPa·s at 25°C.

[0012] As a preferred embodiment, the fluorocarbon resin is tetrafluoroethylene - vinyl ether copolymer resin.

[0013] As a preferred embodiment, the fluorine content of the fluorocarbon resin is 25 - 35 wt%.

[0014] As a preferred embodiment, the preparation method of the modified graphene specifically includes the following steps: S1: Ultrasonically treat graphene in a dispersing solvent to form a uniform suspension; S2: Under nitrogen protection, sequentially add hydroxyethyl acrylate, 2 - acrylamido - 2 - methylpropanesulfonic acid and phosphoric acid - esterified polyetheramine, raise the temperature and stir evenly, then dropwise add ammonium persulfate and keep the temperature for reaction; S3: Centrifuge the reaction product, wash it with ethanol and dry it under vacuum to obtain the product.

[0015] As a preferred embodiment, the preparation method of the modified graphene specifically includes the following steps: S1: Disperse graphene in deionized water, and perform ultrasonic treatment at 800-900W for 30-40 min to form a uniform suspension; S2: Under nitrogen protection, sequentially add hydroxyethyl acrylate, 2-acrylamido-2-methylpropanesulfonic acid, and phosphoric acid esterified polyetheramine to the suspension, heat up to 75-80°C, and keep stirring at a stirring speed of 400-500 rpm for 20-30 min. Then, slowly add ammonium persulfate dropwise and keep reacting for 5-6 h; S3: Centrifuge the reaction product, wash it with ethanol 2-3 times, and vacuum dry it at 70-75°C for 10-12 h to obtain the product.

[0016] As a preferred embodiment, the graphene is few-layer graphene, and the number of layers is 4-7 layers.

[0017] As a preferred embodiment, the mass ratio of the graphene, hydroxyethyl acrylate, 2-acrylamido-2-methylpropanesulfonic acid, and phosphoric acid esterified polyetheramine is (8-8.5):(0.8-1.2):(0.4-0.5):(1.3-1.5).

[0018] As a preferred embodiment, the mass ratio of the graphene, hydroxyethyl acrylate, 2-acrylamido-2-methylpropanesulfonic acid, and phosphoric acid esterified polyetheramine is 8.5:1:0.4:1.4.

[0019] Adding the modified graphene can improve its parallel arrangement in the coating system, extend the penetration paths of water, oxygen, and corrosive ions, and provide a basis for improving the anti-corrosion and water resistance of the coating. Moreover, the polymer chains grafted further fill the chain segment pores of the coating system, ultimately reducing the coating porosity and enhancing the denseness. The sulfonic acid groups can undergo a chelation reaction with the metal surface to form a stable metal-sulfonate complex, inhibiting the anodic dissolution reaction, and the phosphate groups can generate a phosphate passivation film on the metal surface to block the microcell path of electrochemical corrosion, thereby greatly improving the anti-corrosion performance of the coating.

[0020] On the other hand, the hydroxyl groups carried after modification combine with the epoxy groups in the epoxy resin through hydrogen bonds or covalent bonds, enhancing the graphene-resin interfacial bonding force, and providing steric hindrance through the polymer chain segments to prevent excessive aggregation between graphene particles, ensuring long-term dispersion stability, and thus avoiding the precipitation, phase separation, etc. of conventional graphene-based coatings as a whole.

[0021] As a preferred embodiment, the compound functional agent is a composition of polyurethane acrylate, polyvinyl butyral, and boron nitride flakes.

[0022] As a preferred embodiment, the mass ratio of the polyurethane acrylate, polyvinyl butyral, and boron nitride flakes is (4 - 6):(1.5 - 2):(4.5 - 6.5).

[0023] As a preferred embodiment, the mass ratio of the polyurethane acrylate, polyvinyl butyral, and boron nitride flakes is 5:1.5:5.5.

[0024] As a preferred embodiment, the weight-average molecular weight of the polyurethane acrylate is 3000 - 5000 Da.

[0025] As a preferred embodiment, the average particle size of the boron nitride flakes is 2 - 4 μm.

[0026] As a preferred embodiment, the dispersant is at least one of polyurethane-based, polycarboxylates, sodium dodecylbenzenesulfonate, and acrylic copolymer-based.

[0027] As a preferred embodiment, the dispersant is polycarboxylates.

[0028] As a preferred embodiment, the leveling agent is at least one of polyether-modified polysiloxanes, acrylate-based, polyether siloxane copolymers, and polydimethylsiloxanes.

[0029] As a preferred embodiment, the leveling agent is polyether-modified polysiloxanes.

[0030] As a preferred embodiment, the defoaming agent is at least one of polysiloxanes, mineral oils, and fatty acid esters.

[0031] As a preferred embodiment, the defoaming agent is polysiloxanes.

[0032] As a preferred embodiment, the anti-settling agent is at least one of fumed silica, organic bentonite, polyamide wax, polyethylene wax, and hydrogenated castor oil.

[0033] As a preferred embodiment, the anti-settling agent is polyethylene wax.

[0034] As a preferred embodiment, the wetting agent is at least one of modified siloxanes, alkylphenol polyoxyethylene ethers, phosphate esters, and sulfonates.

[0035] As a preferred embodiment, the wetting agent is modified siloxanes.

[0036] As a preferred embodiment, the corrosion inhibitor is a composition of benzotriazole and sodium molybdate.

[0037] As a preferred embodiment, the mass ratio of benzotriazole to sodium molybdate is (3 - 3.6):(1.2 - 1.6).

[0038] As a preferred embodiment, the mass ratio of benzotriazole to sodium molybdate is 3.5:1.5.

[0039] As a preferred embodiment, the solvent is propylene glycol methyl ether acetate.

[0040] A method for preparing a metal anti-corrosion coating based on modified graphene specifically includes the following steps: S1: Mix waterborne epoxy resin, fluorocarbon resin and a solvent, and stir at 800 - 900 rpm for 10 - 15 min; S2: Add modified graphene, a compounding functional agent and a dispersant, and grind with a sand mill until the fineness is ≤ 20 μm; S3: Add the remaining raw materials, mix and disperse at a high speed of 1000 - 1200 rpm for 30 - 40 min, then let it stand and cure in a closed container for 20 - 24 h, and pass through a 200 - 300 mesh sieve to obtain the product.

[0041] The beneficial effects of this application are as follows:

[0042] 1. A metal anti-corrosion coating based on modified graphene provided in this application not only has excellent wear resistance, thermal stability and other properties, but also can greatly improve the dispersibility and compatibility of the modified graphene material in the system, effectively avoiding the precipitation, phase separation and massive agglomeration of the graphene material in the anti-corrosion coating system, and further balancing the long-term anti-corrosion property and mechanical properties of the coating. It can combine good flexibility and peel strength while effectively preventing corrosion, and can comprehensively improve the weather resistance and waterproof performance of the coating, meeting the comprehensive performance requirements of graphene coatings in the existing industrial technology field.

[0043] 2. A metal anti-corrosion coating based on modified graphene provided in this application adds modified graphene to improve its parallel arrangement in the coating system, extending the penetration paths of water, oxygen and corrosive ions, providing a basis for improving the anti-corrosion and water resistance of the coating. And further, the polymer chains grafted fill the chain segment pores of the coating system, finally reducing the coating porosity and enhancing the denseness. The sulfonic acid group can undergo a chelation reaction with the metal surface to form a stable metal-sulfonate complex, inhibiting the anodic dissolution reaction, and the phosphate group generates a phosphate passivation film on the metal surface, which can block the microcell path of electrochemical corrosion, thereby greatly improving the anti-corrosion performance of the coating.

[0044] 3. A metal anti-corrosion coating based on modified graphene provided in the present application. By adding a compound functional agent, the acrylate groups in its composition molecular chain undergo free radical copolymerization with the epoxy groups of the epoxy resin to form a cross-linked network. While improving the flexibility of the coating, hydrogen bonds are formed between the urethane groups and the hydroxyl groups of the modified graphene, reducing the interfacial energy, reducing stress concentration, and improving the compatibility and dispersion effect. On the other hand, the acetal groups in the composition form a dense and continuous film during the curing process, closing the micropores of the coating. And through the synergy of the hydrophobic vinyl groups and the fluorine atoms of the fluorocarbon resin, a low surface energy surface is formed, and further promotes the parallel arrangement of boron nitride flakes in the coating, blocking the diffusion path of molecules and increasing the diffusion resistance, thereby assisting in improving the comprehensive properties such as anti-corrosion and water resistance of the coating system. Description of the Drawings

[0045] Figure 1 It is the morphological electron micrograph of the modified graphene prepared in Example 1 of the present application.

[0046] Figure 2 It is the morphological electron micrograph of the metal anti-corrosion coating prepared in Example 1 of the present application.

[0047] Figure 3 It is the morphological electron micrograph of the metal anti-corrosion coating prepared in Example 2 of the present application.

[0048] Figure 4 It is the morphological electron micrograph of the metal anti-corrosion coating prepared in Comparative Example 1 of the present application. Detailed Description of the Invention

[0049] Example 1

[0050] The metal anti-corrosion coating based on modified graphene, in parts by mass, the raw materials are composed of the following components: 58.8 parts of waterborne epoxy resin, 16.2 parts of fluorocarbon resin, 3 parts of modified graphene, 12 parts of compound functional agent, 1.1 parts of dispersant, 0.6 parts of leveling agent, 0.3 parts of defoaming agent, 2.1 parts of anti-settling agent, 1 part of wetting agent, 1.6 parts of corrosion inhibitor, and 24 parts of solvent.

[0051] The waterborne epoxy resin is bisphenol A epoxy resin, with an epoxy equivalent of 188 g / eq and a viscosity of 12000 mPa·s at 25°C. It is a product of the EPIKOTE-828 model sold by Hexion Inc. in the United States.

[0052] The fluorocarbon resin is a tetrafluoroethylene-vinyl ether copolymer resin, with a fluorine content of 30 wt%. It is a product of the LF-200F model sold by Asahi Glass Co., Ltd. in Japan.

[0053] Preparation method of modified graphene, calculated by mass parts, specifically includes the following steps: S1: Disperse 8.5 parts of graphene in 180 parts of deionized water, and perform ultrasonic treatment at 800W for 35 min to form a uniform suspension; S2: Under nitrogen protection, sequentially add 1 part of hydroxyethyl acrylate, 0.4 part of 2-acrylamido-2-methylpropanesulfonic acid and 1.4 parts of phosphoric acid esterified polyetheramine to the suspension, heat up to 80 °C, stir at a speed of 450 rpm and keep stirring for 30 min, then slowly add 0.05 part of ammonium persulfate dropwise, and keep the reaction at a constant temperature for 5 h; S3: Centrifuge the reaction product, wash it with ethanol three times, and dry it in vacuum at 75 °C for 10 h to obtain the product.

[0054] The phosphoric acid esterified polyetheramine is purchased from the industrial grade fatty alcohol polyoxyethylene ether phosphate product sold by Shandong Xinquansheng Chemical Technology Co., Ltd., China.

[0055] The graphene is few-layer graphene with 5 to 6 layers, and is purchased from the corresponding specification product sold by Zhongke Leiming (Beijing) Technology Co., Ltd., China.

[0056] The compound functional agent is a composition of polyurethane acrylate, polyvinyl butyral and boron nitride flakes, and the mass ratio is 5:1.5:5.5.

[0057] The weight-average molecular weight of the polyurethane acrylate is 3200 Da, and it is purchased from the corresponding specification product sold by Guangdong Bluecol New Materials Co., Ltd., China.

[0058] The average particle size of the boron nitride flakes is 2.8 μm.

[0059] The polyvinyl butyral is purchased from the B-98 model product sold by Eastman Chemical, USA.

[0060] The dispersant is a polycarboxylate dispersant, purchased from the 5040 model product sold by Huada Fine Chemical Co., Ltd., Hubei Province, China; the leveling agent is a polyether modified polysiloxane BYK-381; the defoaming agent is a polysiloxane defoaming agent BYK-022; the anti-settling agent is polyethylene wax, purchased from the industrial grade product sold by Tianchou Chemical Products Co., Ltd., Henan Province, China; the wetting agent is a modified siloxane BYK-349.

[0061] The corrosion inhibitor is a composition of benzotriazole and sodium molybdate, and the mass ratio is 3.5:1.5.

[0062] The solvent is propylene glycol methyl ether acetate.

[0063] Preparation method of metal anti-corrosion coating based on modified graphene, specifically including the following steps: S1: Mix waterborne epoxy resin, fluorocarbon resin and solvent, and stir at 800 rpm for 11 min; S2: Add modified graphene, compound functional agent and dispersant, and grind with a sand mill until the fineness reaches 12 μm; S3: Add the remaining raw materials, mix and disperse at high speed at 1100 rpm for 36 min, then let it stand and cure in a closed container for 24 h, and pass through a 250-mesh sieve to obtain the product.

[0064] The morphologies of the modified graphene and the metal anti-corrosion coating prepared in this example are respectively as shown in Figure 1 and Figure 2 the electron micrographs shown.

[0065] Example 2

[0066] This example only differs from Example 1 in the following aspects: The metal anti-corrosion coating based on modified graphene, by mass, the raw materials are composed of the following components: 62 parts of waterborne epoxy resin, 15 parts of fluorocarbon resin, 3.2 parts of modified graphene, 12 parts of compound functional agent, 1.2 parts of dispersant, 0.7 part of leveling agent, 0.4 part of defoaming agent, 2.2 parts of anti-settling agent, 0.9 part of wetting agent, 1.6 parts of corrosion inhibitor, and 22.4 parts of solvent.

[0067] The compound functional agent is a composition of polyurethane acrylate, polyvinyl butyral and boron nitride flakes, and the mass ratio is 6:1.5:4.5.

[0068] The morphology of the metal anti-corrosion coating prepared in this example is as shown in Figure 3 the electron micrograph shown.

[0069] Example 3

[0070] This example only differs from Example 1 in the following aspects: The metal anti-corrosion coating based on modified graphene, by mass, the raw materials are composed of the following components: 58.5 parts of waterborne epoxy resin, 17.5 parts of fluorocarbon resin, 3.2 parts of modified graphene, 12 parts of compound functional agent, 1.4 parts of dispersant, 0.5 part of leveling agent, 0.4 part of defoaming agent, 1.9 parts of anti-settling agent, 1.2 parts of wetting agent, 1.6 parts of corrosion inhibitor, and 23 parts of solvent.

[0071] The compound functional agent is a composition of polyurethane acrylate, polyvinyl butyral and boron nitride flakes, and the mass ratio is 4:2:6.

[0072] Comparative Example 1

[0073] This comparative example is only different from Example 1 in the following aspects: For the metal anti-corrosion coating based on modified graphene, by mass, the raw materials consist of the following components: 72.5 parts of waterborne epoxy resin, 4.5 parts of fluorocarbon resin, 1.2 parts of modified graphene, 15.5 parts of compound functional agent, 1.1 parts of dispersant, 0.6 parts of leveling agent, 0.3 parts of defoaming agent, 2.1 parts of anti-settling agent, 1 part of wetting agent, 1.6 parts of corrosion inhibitor, and 25 parts of solvent.

[0074] The compound functional agent is a composition of polyurethane acrylate, polyvinyl butyral, and boron nitride flakes, and the mass ratio is 5:1.5:9.

[0075] The morphology of the metal anti-corrosion coating prepared in this comparative example is as Figure 4 shown in the electron micrograph given.

[0076] Comparative Example 2

[0077] This comparative example is only different from Example 1 in the following aspects: For the metal anti-corrosion coating based on modified graphene, by mass, the raw materials consist of the following components: 60 parts of waterborne epoxy resin, 20.5 parts of fluorocarbon resin, 4.5 parts of modified graphene, 3.8 parts of compound functional agent, 1.1 parts of dispersant, 0.6 parts of leveling agent, 0.3 parts of defoaming agent, 2.1 parts of anti-settling agent, 1 part of wetting agent, 1.6 parts of corrosion inhibitor, and 26 parts of solvent.

[0078] Comparative Example 3

[0079] This comparative example is only different from Example 1 in the following aspects: The compound functional agent is a composition of polyurethane acrylate, polyvinyl butyral, and boron nitride flakes, and the mass ratio is 8.5:1:0.5.

[0080] Comparative Example 4

[0081] This comparative example is only different from Example 1 in the following aspects: The compound functional agent is a composition of polyurethane acrylate, polyvinyl butyral, and boron nitride flakes, and the mass ratio is 0.5:6:5.5.

[0082] Comparative Example 5

[0083] This comparative example is only different from Example 1 in the following aspect: the preparation method of modified graphene, in parts by mass, specifically includes the following steps: S1: Disperse 8.5 parts of graphene in 180 parts of deionized water, and perform ultrasonic treatment at 800 W for 35 min to form a uniform suspension; S2: Under nitrogen protection, sequentially add 0.5 part of hydroxyethyl acrylate, 2.5 parts of 2-acrylamido-2-methylpropanesulfonic acid, and 0.5 part of phosphoric acid esterified polyetheramine to the suspension, heat up to 80 °C, stir at a speed of 450 rpm for 30 min while maintaining the temperature, then slowly add 0.05 part of ammonium persulfate dropwise, and carry out a heat preservation reaction for 5 h; S3: Centrifuge the reaction product, wash it 3 times with ethanol, and vacuum dry it at 75 °C for 10 h to obtain the product.

[0084] Comparative Example 6

[0085] This comparative example is only different from Example 1 in the following aspect: the preparation method of modified graphene, in parts by mass, specifically includes the following steps: S1: Disperse 9 parts of graphene in 200 parts of deionized water, and perform ultrasonic treatment at 800 W for 35 min to form a uniform suspension; S2: Under nitrogen protection, sequentially add 3 parts of hydroxyethyl acrylate, 0.1 part of 2-acrylamido-2-methylpropanesulfonic acid, and 0.8 part of phosphoric acid esterified polyetheramine to the suspension, heat up to 80 °C, stir at a speed of 450 rpm for 30 min while maintaining the temperature, then slowly add 0.05 part of ammonium persulfate dropwise, and carry out a heat preservation reaction for 5 h; S3: Centrifuge the reaction product, wash it 3 times with ethanol, and vacuum dry it at 75 °C for 10 h to obtain the product.

[0086] Performance Test

[0087] 1. After the coatings prepared in the examples and comparative examples are cured, perform an anti-corrosion test. Refer to the standard ASTM B117, neutral salt spray, 5% NaCl solution, at a temperature of 35 °C. Spray the coating evenly onto a Q235 carbon steel test piece (size 75×150×2 mm), with a dry film thickness of 80±5 μm. Continuously spray in the salt spray chamber and observe the corrosion situation on the surface of the test piece every 50 h. If there is no red rust expansion at the scratched area of the test piece and no blistering or peeling in the non-scratched area, it is recorded as qualified. Record the corrosion resistance time of the unqualified test pieces, and the results are recorded in Table 1.

[0088] 2. After the coatings prepared in the examples and comparative examples are cured, perform a moisture permeability resistance test. Refer to the standard ASTM E96. Seal the coating film with a thickness of 50 μm in a moisture permeation cup, and calculate the water vapor transmission rate in 24 h by the weighing method. The results are the average of 10 tests and are recorded in Table 1.

[0089] 3. After the coatings prepared in the examples and comparative examples are cured, perform a damp heat aging test. Refer to the standard GB / T 1740, the conditions are 47 °C / 96% RH, and the time is 1000 h. The results are recorded in Table 1.

[0090] 4. The cured coatings prepared in the examples and comparative examples were subjected to peel strength tests. Referring to the standard ASTM D4541, an aluminum ingot with a diameter of 20 mm was bonded to the coating surface, cured for 24 h, and hydraulically loaded until the coating peeled off. The maximum pulling force was recorded, and the average value of 10 tests was taken and recorded in Table 1.

[0091] Table 1 Performance test results

[0092]

[0093] From the final performance test results of the examples and comparative examples, Comparative Examples 1-6 obtained worse performance results compared to the examples. The examples effectively avoided the precipitation, phase separation, and massive agglomeration of graphene materials in the anti-corrosion coating system through the combined action of better-prepared modified graphene particles and compound functional additives. While extending the penetration paths of water, oxygen, and corrosive ions, a hydrogen bond connection effect was formed, reducing the interfacial energy, minimizing stress concentration, improving the compatibility and dispersion effect, and thus comprehensively enhancing the overall performance.

Claims

1. A metal anti-corrosion coating based on modified graphene, characterized in that: The raw materials, by mass parts, include: 50 - 70 parts of waterborne epoxy resin, 10 - 20 parts of fluorocarbon resin, 3 - 5 parts of modified graphene, 8 - 15 parts of compound functional agent, and 15 - 30 parts of solvent; The waterborne epoxy resin is bisphenol A epoxy resin, with an epoxy equivalent of 185 - 192 g / eq and a viscosity of 10000 - 15000 mPa·s at 25°C; The preparation method of the modified graphene includes: S1: dispersing graphene in a solvent and subjecting it to ultrasonic treatment to form a uniform suspension; S2: sequentially adding hydroxyethyl acrylate, 2 - acrylamido - 2 - methylpropanesulfonic acid, and phosphoric acid - esterified polyetheramine under nitrogen protection, heating and stirring, dropping in ammonium persulfate, and carrying out a heat - preservation reaction; S3: centrifugally separating the reaction product, washing, and drying to obtain the product.

2. The metal anti-corrosion coating based on modified graphene according to claim 1, wherein: The graphene is few - layer graphene, with the number of layers being 4 - 7 layers; the mass ratio of the graphene, hydroxyethyl acrylate, 2 - acrylamido - 2 - methylpropanesulfonic acid, and phosphoric acid - esterified polyetheramine is (8 - 8.5):(0.8 - 1.2):(0.4 - 0.5):(1.3 - 1.5).

3. The metal anti-corrosion coating based on modified graphene according to claim 2, wherein: The compound functional agent is a composition of polyurethane acrylate, polyvinyl butyral, and boron nitride flakes, with a mass ratio of (4 - 6):(1.5 - 2):(4.5 - 6.5).

4. The metal anti-corrosion coating based on modified graphene according to claim 3, characterized in that: The mass ratio of the waterborne epoxy resin, fluorocarbon resin, and modified graphene is (55 - 65):(15 - 20):(3 - 4.5).

5. The metal anti-corrosion coating based on modified graphene according to claim 4, characterized in that: The weight - average molecular weight of the polyurethane acrylate is 3000 - 5000 Da; the fluorocarbon resin is a tetrafluoroethylene - vinyl ether copolymer resin, with a fluorine content of 25 - 35 wt%.

6. The metal anti-corrosion coating based on modified graphene according to claim 5, characterized in that: The average particle size of the boron nitride flakes is 2 - 4 μm.

7. The metal anti-corrosion coating based on modified graphene according to claim 6, characterized in that: The raw materials, by mass parts, further include: 0.5 - 2 parts of dispersant, 0.3 - 1 part of leveling agent, 0.2 - 0.8 part of defoamer, 1.5 - 2.5 parts of anti - settling agent, 0.3 - 1.2 parts of wetting agent, and 1 - 3 parts of corrosion inhibitor.

8. The metal anti-corrosion coating based on modified graphene according to claim 7, characterized in that: The dispersant is at least one of polyurethane - type, polycarboxylate, sodium dodecylbenzenesulfonate, and acrylic acid copolymer - type; the wetting agent is at least one of modified siloxane - type, alkylphenol polyoxyethylene ether, phosphate - type, and sulfonate - type.

9. The metal anti-corrosion coating based on modified graphene according to claim 8, characterized in that: The corrosion inhibitor is a composition of benzotriazole and sodium molybdate, with a mass ratio of (3 - 3.6):(1.2 - 1.6).

10. A preparation method of a metal anti-corrosion coating based on modified graphene according to claim 9, characterized in that: Specifically, it includes the following steps: S1: mixing the waterborne epoxy resin, fluorocarbon resin, and solvent, and stirring at 800 - 900 rpm for 10 - 15 min; S2: adding the modified graphene, compound functional agent, and dispersant, and grinding with a sand mill until the fineness is ≤20 μm; S3: adding the remaining raw materials, carrying out high - speed mixing and dispersion at 1000 - 1200 rpm for 30 - 40 min, then standing and curing in a closed container for 20 - 24 h, and passing through a 200 - 300 - mesh sieve to obtain the product.

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