A corrosion-resistant water-based paint and its preparation process

Abstract

The present invention relates to the technical field of paints, and specifically to a corrosion-resistant water-based paint and a preparation process thereof. The present invention overcomes the problems of poor corrosion resistance and mechanical properties of water-based paints. The present invention uses graphene oxide to modify water-based polyurethane, changes the graphene oxide concentration, stannous octoate concentration, prepolymerization temperature, chain extension temperature, and neutralization temperature; changes the ratio of epoxy resin to modified water-based polyurethane and the hard segment content of the modified water-based polyurethane, and significantly improves the mechanical properties of the water-based paint obtained; prepares a corrosion inhibitor, changes the ratio of sodium oleate to aramid nanofibers, the ratio of sodium oleate to zeolite particles, the stirring time of component A and the stirring time of component B; changes the stirring speed and stirring time of the slurry, mixture, and water-based paint; prepares modified graphene oxide, and changes the ratio of quinacridone to modified graphene oxide, and significantly improves the corrosion resistance of the water-based paint obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of paints, in particular to a corrosion-resistant water-based paint and a preparation process thereof. Background Art

[0002] The paint industry is a modern industry. Traditional paints often use organic solvents such as formaldehyde and benzene as film-forming solvents. As a result, they release large amounts of volatile organic compounds (VOCs) during the volatilization process, which not only pollutes the environment but also poses significant risks to human health. In recent years, with growing global environmental awareness and regulations limiting VOC emissions, traditional solvent-based paints have been gradually phased out of the market, replaced by more environmentally friendly water-based paints.

[0003] Water-based paints use water-based polymers as their film-forming materials. They not only avoid the use of organic solvents during manufacturing but also avoid organic solvent emissions during application, fully complying with the internationally recognized "Four E's" (economy, environmental protection, efficiency, and performance). Water-based paints have attracted considerable attention for their low VOC content, non-toxicity, odorlessness, and ease of application. They can be applied to a variety of materials, including wood, metal, plastic, glass, and architectural surfaces, demonstrating excellent development prospects.

[0004] As an environmentally friendly paint, water-based paint has the characteristics of water resistance, wear resistance, yellowing resistance, fast drying and easy use. However, the corrosion resistance and mechanical properties of water-based paint on the market still need to be improved.

[0005] Therefore, a corrosion-resistant water-based paint and a preparation process thereof are proposed. Summary of the Invention

[0006] The object of the present invention is to provide a corrosion-resistant water-based paint and a preparation process thereof. The water-based polyurethane is modified by using graphene oxide, and the concentration of graphene oxide, the concentration of stannous octoate, the prepolymerization temperature, the chain extension temperature and the neutralization temperature are changed, so that the molecular weight of the polyurethane emulsion is increased, and the excellent mechanical properties of the graphene oxide and the hydrogen bonds formed by the abundant oxygen-containing functional groups on its surface enhance the interaction between molecules, so that the mechanical properties of the corrosion-resistant water-based paint obtained are significantly improved; by changing the ratio of epoxy resin and modified water-based polyurethane and the hard segment content of the modified water-based polyurethane, the cohesive energy of the hard segment microregion of the water-based polyurethane is enhanced, so that the polymer has a certain rigidity, and the mechanical properties of the corrosion-resistant water-based paint obtained are improved; by preparing a corrosion inhibitor, the ratio of sodium oleate and aramid nanostructured resin is changed. By adjusting the ratio of rice fiber, sodium oleate and zeolite particles, and the stirring time of component A and component B, the corrosion inhibition components can be completely released, and the obtained corrosion inhibitor can be applied to water-based paint, and the corrosion resistance of the paint is significantly improved; by changing the stirring speed and stirring time of the slurry, mixture and water-based paint, the various components in the water-based paint can be fully dispersed and dissolved during the preparation process, and the corrosion resistance of the obtained water-based paint is improved; by preparing modified graphene oxide, changing the catalyst type, the mass ratio of graphene oxide, catalyst and melamine and the heating temperature of the suspension during the preparation process, and changing the ratio of quinacridone and modified graphene oxide, the shielding effect of graphene on corrosion factors can be fully exerted, and the corrosion resistance of the obtained water-based paint is significantly improved.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] One aspect of the present invention provides a process for preparing a corrosion-resistant water-based paint. The process for preparing the corrosion-resistant water-based paint is as follows:

[0009] Adding epoxy resin and modified waterborne polyurethane to deionized water under stirring conditions and mixing uniformly to obtain a slurry; the stirring speed is 450-550 rpm; the stirring time is 25-35 minutes; zinc phosphate particles and modified graphene oxide are added to the slurry, and stirring is continued at a speed of 300-350 rpm for 55-65 minutes to obtain a mixture; adding a defoamer, a thickener, a dispersant, and a corrosion inhibitor to the mixture, and stirring at a speed of 500-600 rpm for 30-40 minutes to obtain the corrosion-resistant waterborne paint;

[0010] The modified waterborne polyurethane is obtained by graphene oxide through prepolymerization, chain extension and neutralization; the prepolymerization temperature is 70-75°C; the chain extension temperature is 85-95°C; and the neutralization temperature is 50-60°C.

[0011] The modified graphene oxide is obtained by reacting the graphene oxide, a catalyst and melamine in N,N-dimethylformamide; the mass ratio of the graphene oxide, the catalyst and the melamine is 1:0.5:2.5-3.5;

[0012] The corrosion inhibitor comprises sodium oleate, aramid nanofibers and zeolite particles; the ratio of the sodium oleate to the aramid nanofibers is 1-5:1; the ratio of the sodium oleate to the zeolite particles is 1-4:1.2.

[0013] Preferably, the ratio of the epoxy resin to the modified waterborne polyurethane is 1.5-2.1:1.2.

[0014] Preferably, the hard segment content of the modified waterborne polyurethane is 35%-55%.

[0015] Preferably, the dispersant is quinacridone; the ratio of the quinacridone to the modified graphene oxide is 1.8:7-12.

[0016] Preferably, the preparation process of the modified waterborne polyurethane is as follows: adding the graphene oxide to the deionized water and ultrasonically crushing it to obtain a suspension; the concentration of the graphene oxide in the suspension is 1.2-1.8wt%; adding isophorone diisocyanate and the suspension to a three-necked flask and stirring for 0.8h to obtain a mixed solution I; adding PPG-2000 and 1.5-2.5wt% of stannous octoate to the mixed solution I to obtain a prepolymer; mixing ethylene glycol and acetone uniformly and then adding the mixture dropwise to the prepolymer to react for 1.5h to obtain a mixture II; dissolving 2,2-dihydroxymethylpropionic acid in N-methylpyrrolidone to obtain a mixture III; dropping the mixture III into the mixture II to obtain a mixture IV; adding ammonia water to the mixture IV to carry out the neutralization reaction, reacting for 20 minutes, and then cooling to room temperature to obtain the modified waterborne polyurethane.

[0017] Preferably, the preparation process of the modified graphene oxide is as follows: ultrasonically dispersing the graphene oxide, catalyst and melamine in N,N-dimethylformamide for 1 hour to obtain a suspension; heating the suspension to 80-100°C and stirring for 10 hours to obtain a brown suspension; washing the brown suspension three times with N,N-dimethylformamide and 100°C boiling water, and then drying at 70°C for 20 hours to obtain the modified graphene oxide.

[0018] Preferably, the catalyst is one of dicyclohexylcarbodiimide, diisopropylcarbodiimide, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and N,N-di-tert-butylcarbodiimide.

[0019] Preferably, the graphene oxide is in the form of flakes.

[0020] Preferably, the preparation process of the corrosion inhibitor is as follows: 1 / 3 of the total weight of the sodium oleate is mixed with the aramid nanofiber in the deionized water and stirred for 20-35 minutes to obtain component A; the remaining 2 / 3 of the sodium oleate is mixed with the zeolite particles in the deionized water and stirred for 15-20 hours to obtain component B; and the component A and the component B are mixed to obtain the corrosion inhibitor.

[0021] Another aspect of the present invention provides a corrosion-resistant water-based paint, wherein raw materials for producing the corrosion-resistant water-based paint include epoxy resin, modified water-based polyurethane, corrosion inhibitor, modified graphene oxide and quinacridone.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The present invention uses graphene oxide to modify waterborne polyurethane. Graphene oxide is evenly grafted onto polyurethane molecules, increasing the molecular weight of the polyurethane emulsion. The excellent mechanical properties of graphene oxide and the hydrogen bonds formed by the abundant oxygen-containing functional groups on its surface enhance the interaction between molecules. By changing the concentration of graphene oxide, stannous octoate concentration, prepolymerization temperature, chain extension temperature, and neutralization temperature, a modified waterborne polyurethane is obtained. The corrosion-resistant waterborne paint obtained by mixing it with an epoxy resin as a matrix has a tensile strength of 1.15 MPa. No cracks, wrinkles, or peeling phenomena are observed in an impact test at 50 cm, and the mechanical properties are significantly improved.

[0024] 2. The present invention enhances the cohesive energy of the hard segment microregions of the waterborne polyurethane by changing the ratio of epoxy resin and modified waterborne polyurethane and the hard segment content of the modified waterborne polyurethane, so that the polymer has a certain rigidity. The mechanical properties of the corrosion-resistant waterborne paint obtained are improved, and the tensile strength is 1.37 MPa. No cracks, wrinkles or peeling were observed in the impact test at 50 cm.

[0025] 3. The present invention prepares a corrosion inhibitor by changing the ratio of sodium oleate to aramid nanofibers, the ratio of sodium oleate to zeolite particles, the stirring time of component A, and the stirring time of component B, so that the sodium oleate adsorbed on the zeolite particles promotes the connection between the aramid nanofibers and the zeolite particles, thereby fully releasing the sodium ions inside the zeolite particles, increasing the pH value of the solution, and completely releasing the corrosion-inhibiting components. The prepared corrosion inhibitor is applied to water-based paint, and the corrosion resistance of the paint is significantly improved. There is no abnormality after immersion in 50g / L sulfuric acid solution for 192 hours, and there is no abnormality after immersion in 50g / L sodium hydroxide solution for 168 hours. In the salt spray resistance test, there is no blistering, peeling, rusting, or cracking for 3620 hours.

[0026] 4. The present invention can fully disperse and dissolve the various components in the water-based paint during the preparation process by changing the stirring speed and stirring time of the slurry, the mixture and the water-based paint, thereby improving the corrosion resistance of the prepared water-based paint. The paint has no abnormalities after being immersed in a 50g / L sulfuric acid solution for 192 hours and in a 50g / L sodium hydroxide solution for 168 hours. In the salt spray resistance test, no bubbling, peeling, rusting or cracking occurs for 3620 hours.

[0027] 5. The present invention prepares modified graphene oxide and changes the catalyst type, the mass ratio of graphene oxide, catalyst and melamine, and the suspension heating temperature during the preparation process, thereby improving the dispersibility of the modified graphene oxide and extending the diffusion path of the corrosive medium to the matrix, thereby improving the corrosion resistance of the composite material. By changing the ratio of quinacridone and modified graphene oxide, quinacridone and modified graphene oxide can form a π-π bond, thereby improving the dispersibility of each other in the water-based paint. Quinacridone is adsorbed on the surface of graphene to form a scaly crystal structure, which can give full play to the shielding effect of graphene against corrosion factors. The corrosion resistance of the prepared water-based paint is significantly improved. There is no abnormality after immersion in 50g / L sulfuric acid solution for 192 hours, no abnormality after immersion in 50g / L sodium hydroxide solution for 168 hours, and no blistering, peeling, rusting, or cracking occurs after 3691 hours in the salt spray resistance test. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Graph showing the mechanical properties test results of Examples 17, 19-22 of the present invention. DETAILED DESCRIPTION

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0030] See also Figure 1 The present invention provides a corrosion-resistant water-based paint and a preparation process thereof, and the technical solution is as follows:

[0031] The substance information involved in the present invention is as follows:

[0032] Epoxy resin CAS: 24969-06-0; Zinc phosphate CAS: 7779-90-0; Sodium oleate CAS: 143-19-1; Zeolite CAS: 1318-02-1; Quinacridone CAS: 1047-16-1; Isophorone diisocyanate CAS: 4098-71-9; Stannous octoate CAS: 301-10-0; Ethylene glycol CAS: 107-21-1; Acetone CAS: 67-64-1; 2,2-Dimethylolpropionic acid CAS: 4767-03-7; N-Methylpyrrolidone CAS: 872-50-4; Ammonia CAS: 1336-21-6; Polydimethylsiloxane CAS: 901 6-00-6; polyacrylamide CAS: 9003-05-8; melamine CAS: 108-78-1; N,N-dimethylformamide CAS: 68-12-2; dicyclohexylcarbodiimide CAS: 538-75-0; diisopropylcarbodiimide CAS: 693-13-0; 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide CAS: 1892-57-5; N,N-di-tert-butylcarbodiimide CAS: 691-24-7; graphene oxide was purchased from Beijing Huawei Ruike Chemical Technology Co., Ltd.; aramid nanofiber was purchased from Beijing Tongtai Jiahua Technology Co., Ltd.; PPG-2000 was purchased from Shanghai Kaibite Chemical Co., Ltd.

[0033] It should be noted that, all parts in the present invention are parts by weight.

[0034] Example 1

[0035] Preparation of modified waterborne polyurethane: 10 parts of graphene oxide are added to deionized water and ultrasonically crushed to obtain a suspension; the concentration of graphene oxide in the suspension is 1.2wt%; 20 parts of isophorone diisocyanate and the suspension are added to a three-necked flask, and stirred at 70°C for 0.8h to obtain a mixed solution one; 1.0wt% of PPG-2000 and 1.5wt% of stannous octoate are added to the mixed solution one to obtain a prepolymer; ethylene glycol and acetone are mixed uniformly in a ratio of 1:1.5 and then added dropwise to the prepolymer, and reacted at 85°C for 1.5h to obtain a mixture two; 5 parts of 2,2-dihydroxymethylpropionic acid are dissolved in 8 parts of N-methylpyrrolidone to obtain a mixture three; the mixture three is dropped into the mixture two to obtain a mixture four; 3 parts of ammonia water are added to the mixture four for neutralization reaction, and the mixture is reacted at 50°C for 20min and then cooled to room temperature to obtain a modified waterborne polyurethane.

[0036] Preparation of corrosion inhibitor: 6 parts of sodium oleate and aramid nanofibers are mixed and stirred in 25 parts of deionized water for 20 minutes to obtain component A; 12 parts of sodium oleate and zeolite particles are mixed and stirred in 35 parts of deionized water for 15 hours to obtain component B; component A and component B are mixed to obtain a corrosion inhibitor; the ratio of sodium oleate to aramid nanofibers is 1:1; the ratio of sodium oleate to zeolite particles is 1:1.2.

[0037] Preparation of modified graphene oxide: 120 mg of graphene oxide, catalyst dicyclohexylcarbodiimide and melamine were ultrasonically dispersed in 100 ml of N,N-dimethylformamide for 1 hour to obtain a suspension; the suspension was heated to 80°C and stirred for 10 hours to obtain a brown suspension; the brown suspension was rinsed three times with N,N-dimethylformamide and 100°C boiling water, and then dried at 70°C for 20 hours to obtain the modified graphene oxide; the mass ratio of graphene oxide, catalyst and melamine was 1:0.5:2.5; the graphene oxide was in the form of flakes.

[0038] Preparation of corrosion-resistant water-based paint: 70 parts of epoxy resin and modified water-based polyurethane are added to deionized water under stirring conditions and mixed evenly to obtain a slurry; the stirring speed is 450 rpm; the stirring time is 25 minutes; 5 parts of zinc phosphate particles and 7 parts of modified graphene oxide are added to the slurry, and stirring is continued at a speed of 300 rpm for 55 minutes to obtain a mixture; 1.5 parts of defoaming agent polydimethylsiloxane, 1.2 parts of thickener polyacrylamide, dispersant quinacridone and 5 parts of corrosion inhibitor are added to the mixture, and stirring is carried out at a speed of 500 rpm for 30 minutes to obtain a corrosion-resistant water-based paint; the ratio of epoxy resin to modified water-based polyurethane is 1.5:1.2; the hard segment content of the modified water-based polyurethane is 35%; the ratio of quinacridone to modified graphene oxide is 1.8:7.

[0039] Examples 2-14

[0040] Refer to the preparation method and parameter conditions of Example 1, the specific differences are shown in Table 1.

[0041] Table 1 Specific preparation parameters of Examples 2-14

[0042] Example Graphene oxide concentration / wt% Stannous octoate concentration / wt% Prepolymerization temperature / ℃ Chain extension temperature / ℃ Neutralization temperature / ℃ Example 2 1.4 1.5 70 85 50 Example 3 1.6 1.5 70 85 50 Example 4 1.8 1.5 70 85 50 Example 5 1.4 1.8 70 85 50 Example 6 1.4 2.2 70 85 50 Example 7 1.4 2.5 70 85 50 Example 8 1.4 1.8 72 85 50 Example 9 1.4 1.8 75 85 50 Example 10 1.4 1.8 72 88 50 Example 11 1.4 1.8 72 90 50 Example 12 1.4 1.8 72 95 50 Example 13 1.4 1.8 72 90 54 Example 14 1.4 1.8 72 90 60

[0043] Comparative Example 1

[0044] A corrosion-resistant water-based paint was prepared according to the method of Example 1, except that the water-based polyurethane was not modified.

[0045] Example 15 Mechanical properties test

[0046] Tensile strength test: The film sample is tested using a tensile testing machine. The sample is a dumbbell-shaped specimen and is placed at room temperature for 24 hours to eliminate internal stress. The tensile rate is 1 mm / min.

[0047] Impact strength: The impact strength of water-based paint was tested according to the standard GB / T1732-2020 "Determination of impact resistance of paint films"; the results are shown in Table 2.

[0048] Table 2 Mechanical properties test of Examples 1-14 and Comparative Example 1

[0049] Example Tensile strength / MPa Impact strength / cm Example 1 0.87 45 Example 2 0.89 50 Example 3 0.91 45 Example 4 0.88 45 Example 5 0.95 50 Example 6 0.94 50 Example 7 0.91 45 Example 8 0.98 50 Example 9 0.97 50 Example 10 1.04 50 Example 11 1.15 50 Example 12 0.86 50 Example 13 1.28 50 Example 14 1.02 50 Comparative Example 1 0.43 35

[0050] As can be seen from Table 2, in Examples 1-4, when the graphene oxide concentration is too low, the distribution in the aqueous polyurethane is relatively sparse, and the interaction between the two weakens, thereby affecting the mechanical properties of the material; when the graphene oxide concentration is too high, agglomeration easily occurs between the graphene sheets, forming larger particles, which serve as stress concentration points in the aqueous polyurethane matrix, causing the mechanical properties of the material to decline. In Example 2, the effect is best when the graphene oxide concentration is 1.4wt%. The main function of stannous octoate in the process of synthesizing modified aqueous polyurethane is to promote the reaction between the isocyanate group and the hydroxyl group, i.e., to promote the growth of the polymer chain. In Examples 2, 5-7, when the stannous octoate concentration is too low, its catalytic efficiency is relatively low, causing insufficient polymerization degree, thereby affecting the mechanical properties of the aqueous polyurethane; when the stannous octoate concentration is too high, it can cause the aqueous polyurethane to gel prematurely in the preparation process, which can affect the cell structure of the polyurethane, making the cells mostly closed cells, limiting the deformation capacity of the foam when impacted, causing the effect of energy absorption and dispersion to weaken, and impact resistance to decline. In Example 5, the mechanical properties of the waterborne polyurethane were optimal when the stannous octoate concentration was 1.8 wt%. In Examples 5, 8-9, if the prepolymerization temperature was too high, the molecular weight distribution of the prepolymer would be uneven, affecting the mechanical properties of the waterborne polyurethane. At high temperatures, the raw materials could thermally degrade, resulting in a decrease in the quality of the prepolymer. If the prepolymerization temperature was too low, stress concentration points would be generated, reducing the mechanical properties of the waterborne polyurethane. In Example 8, the best results were achieved when the prepolymerization temperature was 72°C. In Examples 8, 10-12, if the chain extension reaction temperature was too high, the chain segment length distribution would be uneven, affecting the crosslinking degree and molecular weight distribution of the waterborne polyurethane. At high temperatures, the polyurethane segments would thermally degrade, resulting in a decrease in mechanical properties. If the chain extension reaction temperature was too low, the chain extension reaction would be incomplete, leaving unreacted functional groups and insufficient chain segment growth, which would also negatively impact the mechanical properties of the waterborne polyurethane. In Example 11, the optimal chain extension reaction temperature was 90°C. In Examples 11, 13-14, if the neutralization reaction temperature is too high, the ionic crosslinking effect may be too strong, resulting in too large a distance between the molecular chains of the waterborne polyurethane, thereby reducing its mechanical properties; if the neutralization reaction temperature is too low, incomplete neutralization may result, leaving unreacted functional groups such as carboxyl or amino groups. In addition, the stability of the polyurethane emulsion will also decrease, thereby reducing the mechanical properties of the waterborne polyurethane; in Example 13, when the graphene oxide concentration is 1.4wt% and the stannous octoate concentration is 1.8wt%, the prepolymerization reaction is carried out at 72°C, the chain extension reaction is carried out at 90°C, and the neutralization reaction is carried out at 54°C, the modified waterborne polyurethane obtained has the best mechanical properties, and the corrosion-resistant waterborne paint prepared by mixing it with epoxy resin as a matrix has a tensile strength of 1.15MPa, and no cracks, wrinkles or peeling are observed in an impact test at 50cm.In Comparative Example 1, when unmodified waterborne polyurethane was applied to waterborne paint, its mechanical properties were significantly reduced.

[0051] Example 16

[0052] Preparation of modified waterborne polyurethane: 10 parts of graphene oxide are added to deionized water and ultrasonically crushed to obtain a suspension; the concentration of graphene oxide in the suspension is 1.4wt%; 20 parts of isophorone diisocyanate and the suspension are added to a three-necked flask, and stirred at 72°C for 0.8h to obtain a mixed solution one; 1.0wt% of PPG-2000 and 1.8wt% of stannous octoate are added to the mixed solution one to obtain a prepolymer; ethylene glycol and acetone are mixed uniformly in a ratio of 1:1.5 and then added dropwise to the prepolymer, and reacted at 90°C for 1.5h to obtain a mixture two; 5 parts of 2,2-dihydroxymethylpropionic acid are dissolved in 8 parts of N-methylpyrrolidone to obtain a mixture three; the mixture three is dropped into the mixture two to obtain a mixture four; 3 parts of ammonia water are added to the mixture four for neutralization reaction, and the mixture is reacted at 54°C for 20min and then cooled to room temperature to obtain a modified waterborne polyurethane.

[0053] Preparation of a corrosion inhibitor: 6 parts of sodium oleate and aramid nanofibers are mixed and stirred in 25 parts of deionized water for 20 minutes to obtain component A; 12 parts of sodium oleate and zeolite particles are mixed and stirred in 35 parts of deionized water for 15 hours to obtain component B; component A and component B are mixed to obtain a corrosion inhibitor; the ratio of sodium oleate to aramid nanofibers is 1:1; the weight ratio of sodium oleate to zeolite particles is 1:1.2.

[0054] Preparation of modified graphene oxide: 120 mg of graphene oxide, catalyst dicyclohexylcarbodiimide and melamine were ultrasonically dispersed in 100 ml of N,N-dimethylformamide for 1 hour to obtain a suspension; the suspension was heated to 80°C and stirred for 10 hours to obtain a brown suspension; the brown suspension was rinsed three times with N,N-dimethylformamide and 100°C boiling water, and then dried at 70°C for 20 hours to obtain the modified graphene oxide; the mass ratio of graphene oxide, catalyst and melamine was 1:0.5:2.5; the graphene oxide was in the form of flakes.

[0055] Preparation of corrosion-resistant water-based paint: 70 parts of epoxy resin and modified water-based polyurethane are added to deionized water under stirring conditions and mixed evenly to obtain a slurry; the stirring speed is 450 rpm; the stirring time is 25 minutes; 5 parts of zinc phosphate particles and 7 parts of modified graphene oxide are added to the slurry, and stirring is continued at a speed of 300 rpm for 55 minutes to obtain a mixture; 1.5 parts of defoaming agent polydimethylsiloxane, 1.2 parts of thickener polyacrylamide, dispersant quinacridone and 5 parts of corrosion inhibitor are added to the mixture, and stirring is carried out at a speed of 500 rpm for 30 minutes to obtain a corrosion-resistant water-based paint; the ratio of epoxy resin to modified water-based polyurethane is 1.7:1.2; the hard segment content of the modified water-based polyurethane is 35%; the ratio of quinacridone to modified graphene oxide is 1.8:7.

[0056] Examples 17-22

[0057] Referring to the preparation method and parameter conditions of Example 16, the specific differences are shown in Table 3.

[0058] Example 23 Mechanical properties test

[0059] Tensile strength test: The film sample is tested using a tensile testing machine. The sample is a dumbbell-shaped specimen and is placed at room temperature for 24 hours to eliminate internal stress. The tensile rate is 1 mm / min.

[0060] Impact strength: The impact strength of water-based paint was tested according to the standard GB / T1732-2020 "Determination of impact resistance of paint film"; the results are shown in Table 3 and Figure 1 shown.

[0061] Table 3 Mechanical properties test of Examples 16-22

[0062] Example Ratio of epoxy resin and modified waterborne polyurethane Hard segment content of modified waterborne polyurethane / % Tensile strength / MPa Impact strength / cm Example 16 1.7：1.2 35 1.18 50 Example 17 1.8：1.2 35 1.23 50 Example 18 2.1：1.2 35 1.20 45 Example 19 1.8：1.2 40 1.29 50 Example 20 1.8：1.2 45 1.37 50 Example 21 1.8：1.2 50 1.32 50 Example 22 1.8：1.2 55 1.26 45

[0063] It can be seen from Table 3 that in Example 18, the content of epoxy resin is too high. Since the epoxy resin itself has high rigidity and hardness, the overall rigidity of the material will increase, while the toughness will be relatively reduced. Therefore, the brittleness of the material will increase and the impact resistance will decrease. In Examples 11 and 16, when the content of modified waterborne polyurethane is too high, due to the good flexibility of the polyurethane molecular chain, the overall toughness of the material will increase, while the rigidity will be relatively reduced, so that the tensile strength of the material will decrease. In Example 17, the comprehensive mechanical properties are best when the ratio of epoxy resin to modified waterborne polyurethane is 1.8:1.2. The hard segment microregion of waterborne polyurethane has strong polarity and is easy to form hydrogen bonds, which enhances the cohesive energy of the microregion and makes the polymer have a certain rigidity, thereby giving the polyurethane good tensile strength and impact resistance. As shown in Tables 3 and Figure 1It can be seen that in Examples 17, 19-22, the hard segment content of the modified waterborne polyurethane is too low, which leads to insufficient hardness and rigidity of the waterborne polyurethane, making the material too soft and easy to deform; in addition, the hard segment will also affect the heat resistance of the polyurethane. If the hard segment content is too low, the heat resistance of the corrosion-resistant waterborne paint obtained will be reduced, and deformation and degradation will easily occur at high temperatures, thereby greatly reducing the mechanical properties; as the hard segment content increases, the cohesion and structural stability of the material will be enhanced, and the tensile strength of the waterborne polyurethane will increase accordingly. When the hard segment content is 45%, the tensile strength reaches the maximum; however, in Examples 21-22, too high a hard segment content will lead to poor compatibility between the soft and hard segments, which in turn affects the mechanical properties of the material. In Example 20, when the hard segment content of the modified waterborne polyurethane is 45% and the weight ratio of epoxy resin to modified waterborne polyurethane is 1.8:1.2, the corrosion-resistant waterborne paint obtained has the best mechanical properties and a tensile strength of 1.37 MPa. No cracks, wrinkles or peeling were observed in the impact test at 50 cm.

[0064] Example 24

[0065] The modified waterborne polyurethane was prepared according to the method of Example 16 above.

[0066] Preparation of corrosion inhibitor: 6 parts of sodium oleate and aramid nanofibers are mixed and stirred in 25 parts of deionized water for 20 minutes to obtain component A; 12 parts of sodium oleate and zeolite particles are mixed and stirred in 35 parts of deionized water for 15 hours to obtain component B; component A and component B are mixed to obtain a corrosion inhibitor; the ratio of sodium oleate to aramid nanofibers is 2:1; the ratio of sodium oleate to zeolite particles is 1:1.2.

[0067] Preparation of modified graphene oxide: 120 mg of graphene oxide, catalyst dicyclohexylcarbodiimide and melamine were ultrasonically dispersed in 100 ml of N,N-dimethylformamide for 1 hour to obtain a suspension; the suspension was heated to 80°C and stirred for 10 hours to obtain a brown suspension; the brown suspension was rinsed three times with N,N-dimethylformamide and 100°C boiling water, and then dried at 70°C for 20 hours to obtain the modified graphene oxide; the mass ratio of graphene oxide, catalyst and melamine was 1:0.5:2.5; the graphene oxide was in the form of flakes.

[0068] Preparation of corrosion-resistant water-based paint: 70 parts of epoxy resin and modified water-based polyurethane are added to deionized water under stirring conditions and mixed evenly to obtain a slurry; the stirring speed is 450 rpm; the stirring time is 25 minutes; 5 parts of zinc phosphate particles and 7 parts of modified graphene oxide are added to the slurry, and stirring is continued at a speed of 300 rpm for 55 minutes to obtain a mixture; 1.5 parts of defoaming agent polydimethylsiloxane, 1.2 parts of thickener polyacrylamide, dispersant quinacridone and 5 parts of corrosion inhibitor are added to the mixture, and stirring is carried out at a speed of 500 rpm for 30 minutes to obtain a corrosion-resistant water-based paint; the ratio of epoxy resin to modified water-based polyurethane is 1.8:1.2; the hard segment content of the modified water-based polyurethane is 45%; the ratio of quinacridone to modified graphene oxide is 1.8:7.

[0069] Examples 25-35

[0070] Referring to the preparation method and parameter conditions of Example 24, the specific differences are shown in Table 4.

[0071] Table 4 Specific preparation parameters of Examples 25-35

[0072] Example The ratio of sodium oleate and aramid nanofiber The ratio of sodium oleate and zeolite particles Stirring time of component A / min Stirring time of component B / h Example 25 3：1 1：1.2 20 15 Example 26 4：1 1：1.2 20 15 Example 27 5：1 1：1.2 20 15 Example 28 3：1 2.5：1.2 20 15 Example 29 3：1 3.5：1.2 20 15 Example 30 3：1 4：1.2 20 15 Example 31 3：1 3.5：1.2 25 15 Example 32 3：1 3.5：1.2 30 15 Example 33 3：1 3.5：1.2 35 15 Example 34 3：1 3.5：1.2 30 18 Example 35 3：1 3.5：1.2 30 20

[0073] Example 36 Corrosion resistance test

[0074] Acid resistance test: Test the acid resistance of water-based paint in 50g / L sulfuric acid solution for 192h according to Method A of GB / T9274-1988 standard;

[0075] Alkali resistance test: Test the alkali resistance of water-based paint in 50g / L sodium hydroxide solution for 168h according to method A of GB / T9274-1988 standard;

[0076] Salt spray resistance: The salt spray resistance of water-based paint was tested according to GB / T1771-2007. The coating thickness was 100±10μm. The time for blistering, peeling, rusting, and cracking to occur was tested. The results are shown in Table 5.

[0077] Table 5 Corrosion resistance test of Examples 20, 24-35

[0078] Example Acid resistance Alkali resistance Salt spray resistance / h Example 20 A few rust spots A few rust spots 3544 Example 24 A few rust spots A few rust spots 3552 Example 25 No abnormalities No abnormalities 3560 Example 26 No abnormalities No abnormalities 3552 Example 27 No abnormalities No abnormalities 3543 Example 28 A few rust spots A few rust spots 3561 Example 29 No abnormalities No abnormalities 3570 Example 30 A few rust spots A few rust spots 3560 Example 31 No abnormalities No abnormalities 3575 Example 32 No abnormalities No abnormalities 3600 Example 33 No abnormalities No abnormalities 3583 Example 34 No abnormalities No abnormalities 3620 Example 35 No abnormalities No abnormalities 3619

[0079] As shown in Table 5, in Examples 20, 24-27, the ratio of sodium oleate to aramid nanofibers was varied. If the sodium oleate ratio was too low, the modified aramid nanofibers could not be fully coated, resulting in a decrease in the corrosion inhibitor's corrosion resistance. If the sodium oleate ratio was too high, the corrosion inhibitor contained excessive oily components, which reduced the reinforcement or modification effect of the aramid nanofibers. Excessive sodium oleate also affected the dispersibility of the aramid nanofibers in deionized water, ultimately affecting the uniformity and stability of the corrosion inhibitor. In Example 25, a sodium oleate to aramid nanofiber ratio of 3:1 allowed the corrosion inhibitor to fully function. In Examples 25, 28-30, the ratio of sodium oleate to zeolite particles was varied. If the sodium oleate ratio was too low, the connection between the zeolite particles and the aramid nanofibers could not be promoted. If the sodium oleate ratio was too high, the sodium oleate over-coated the zeolite particles, hindering the release of sodium ions from the zeolite particles and the increase in pH. This prevented the effective release of the corrosion-inhibiting components, resulting in poor corrosion resistance in the resulting water-based paint. In Example 29, a sodium oleate to zeolite particle ratio of 3.5:1.2 achieved the best corrosion resistance. In Examples 29, 31-33, stirring component A for too short a time can cause the aramid nanofibers to agglomerate, forming larger particles, reducing the effective surface area of ​​the corrosion inhibitor and thus affecting its corrosion inhibition ability. Stirring for too long can cause degradation or chemical changes in the sodium oleate or aramid nanofibers, negatively impacting the performance of the corrosion inhibitor. In Example 32, a stirring time of 30 minutes was optimal for component A. In Examples 32, 34-35, stirring component B for too short a time prevented the sodium oleate from fully coating the zeolite particle surface, resulting in poor dispersion of the zeolite particles in deionized water and affecting the uniformity and stability of the corrosion inhibitor. Increasing the stirring time facilitated more uniform sodium oleate coating the zeolite particle surface and allowed the zeolite particles to fully disperse in deionized water, thereby enhancing the adsorption capacity and ion exchange properties of the zeolite particles and improving the corrosion resistance of the corrosion inhibitor. However, prolonged stirring did not further improve the performance of the corrosion inhibitor. In Example 34, when the ratio of sodium oleate to aramid nanofibers is 3:1, the ratio of sodium oleate to zeolite particles is 3.5:1.2, the stirring time of component A is 30 minutes, and the stirring time of component B is 18 hours, the obtained corrosion inhibitor is applied to water-based paint, and the paint has the best corrosion resistance. There is no abnormality after immersion in 50g / L sulfuric acid solution for 192 hours, and there is no abnormality after immersion in 50g / L sodium hydroxide solution for 168 hours. In the salt spray resistance test, there is no blistering, peeling, rusting, and cracking for 3620 hours.

[0080] Example 37

[0081] The modified waterborne polyurethane was prepared according to the method of Example 16 above.

[0082] Preparation of corrosion inhibitor: 6 parts of sodium oleate and aramid nanofibers are mixed and stirred in 25 parts of deionized water for 30 minutes to obtain component A; 12 parts of sodium oleate and zeolite particles are mixed and stirred in 35 parts of deionized water for 18 hours to obtain component B; component A and component B are mixed to obtain a corrosion inhibitor; the ratio of sodium oleate to aramid nanofibers is 3:1; the ratio of sodium oleate to zeolite particles is 3.5:1.2.

[0083] Preparation of modified graphene oxide: 120 mg of graphene oxide, catalyst dicyclohexylcarbodiimide and melamine were ultrasonically dispersed in 100 ml of N,N-dimethylformamide for 1 hour to obtain a suspension; the suspension was heated to 80°C and stirred for 10 hours to obtain a brown suspension; the brown suspension was rinsed three times with N,N-dimethylformamide and 100°C boiling water, and then dried at 70°C for 20 hours to obtain the modified graphene oxide; the mass ratio of graphene oxide, catalyst and melamine was 1:0.5:2.5; the graphene oxide was in the form of flakes.

[0084] Preparation of corrosion-resistant water-based paint: 70 parts of epoxy resin and modified water-based polyurethane are added to deionized water under stirring conditions and mixed evenly to obtain a slurry; the stirring speed is 480 rpm; the stirring time is 25 minutes; 5 parts of zinc phosphate particles and 7 parts of modified graphene oxide are added to the slurry, and stirring is continued at a speed of 300 rpm for 55 minutes to obtain a mixture; 1.5 parts of defoaming agent polydimethylsiloxane, 1.2 parts of thickener polyacrylamide, dispersant quinacridone and 5 parts of corrosion inhibitor are added to the mixture, and stirring is carried out at a speed of 500 rpm for 30 minutes to obtain a corrosion-resistant water-based paint; the ratio of epoxy resin to modified water-based polyurethane is 1.8:1.2; the hard segment content of the modified water-based polyurethane is 45%; the ratio of quinacridone to modified graphene oxide is 1.8:7.

[0085] Examples 38-53

[0086] Referring to the preparation method and parameter conditions of Example 37, the specific differences are shown in Table 6.

[0087] Table 6 Specific preparation parameters of Examples 38-53

[0088]

[0089] Example 54 Corrosion resistance test

[0090] Acid resistance test: Test the acid resistance of water-based paint in 50g / L sulfuric acid solution for 192h according to Method A of GB / T9274-1988 standard;

[0091] Alkali resistance test: Test the alkali resistance of water-based paint in 50g / L sodium hydroxide solution for 168h according to Method A of GB / T9274-1988 standard;

[0092] Salt spray resistance: The salt spray resistance of water-based paint was tested according to GB / T1771-2007. The coating thickness was 100±10μm. The time for blistering, peeling, rusting, and cracking to occur was tested. The results are shown in Table 7.

[0093] Table 7 Corrosion resistance test of Examples 34, 37-53

[0094] Example Acid resistance Alkali resistance Salt spray resistance / h Example 34 No abnormalities No abnormalities 3620 Example 37 No abnormalities No abnormalities 3623 Example 38 No abnormalities No abnormalities 3627 Example 39 No abnormalities No abnormalities 3633 Example 40 No abnormalities No abnormalities 3628 Example 41 No abnormalities No abnormalities 3635 Example 42 No abnormalities No abnormalities 3640 Example 43 No abnormalities No abnormalities 3636 Example 44 No abnormalities No abnormalities 3643 Example 45 No abnormalities No abnormalities 3639 Example 46 A few rust spots A few rust spots 3633 Example 47 No abnormalities No abnormalities 3648 Example 48 No abnormalities No abnormalities 3645 Example 49 No abnormalities No abnormalities 3650 Example 50 No abnormalities No abnormalities 3646 Example 51 A few rust spots A few rust spots 3638 Example 52 No abnormalities No abnormalities 3654 Example 53 No abnormalities No abnormalities 3650

[0095] As can be seen in Table 7, in Examples 34, 37-43, stirring the slurry too high or too low resulted in uneven dispersion of the epoxy resin and modified waterborne polyurethane particles, leading to localized agglomeration. This compromised the uniformity and stability of the slurry, affecting the effectiveness of subsequent component additions and the corrosion resistance of the waterborne paint. If the stirring time is too short, the epoxy resin and modified waterborne polyurethane cannot be fully dissolved and dispersed in deionized water. If the stirring time is too long, the particles in the slurry will be over-dispersed, resulting in a loss of dispersion stability and aggregation and precipitation. In Example 42, stirring at 520 rpm for 31 minutes was optimal. In Examples 42, 44-48, stirring the mixture too high resulted in uneven distribution of the zinc phosphate particles and graphene oxide in the slurry. If the stirring speed is too low, the particles in the slurry cannot be fully dispersed. Both of these factors can lead to a decrease in the corrosion resistance of the waterborne paint. If the stirring time is too long, the zinc phosphate particles and graphene oxide will be over-dispersed in the slurry, or even destroy its structure, affecting the corrosion resistance of the paint; if the stirring time is too short, the zinc phosphate particles and graphene oxide may not be fully integrated into the slurry, resulting in a decrease in the corrosion resistance of the paint. In Examples 47, 49-53, the stirring speed of the water-based paint is too high, and the local concentration of the additive is too high or too low, affecting the corrosion resistance and stability of the paint; if the stirring speed is too low, the additive cannot be fully dispersed and dissolved, resulting in its effect not being fully exerted, and the corrosion resistance of the water-based paint will also decrease. If the stirring time is too long, the paint will lose dispersion stability; if the stirring time is too short, the additive cannot be fully integrated into the paint, both of which will have a negative impact on the corrosion resistance of the water-based paint. In Example 52, when the slurry was stirred at 520 rpm for 31 minutes, the mixture was stirred at 315 rpm for 60 minutes, and the water-based paint was stirred at 540 rpm for 35 minutes, the corrosion-resistant water-based paint finally obtained was immersed in a 50 g / L sulfuric acid solution for 192 hours without abnormalities, immersed in a 50 g / L sodium hydroxide solution for 168 hours without abnormalities, and in the salt spray resistance test, there was no bubbling, peeling, rusting, or cracking for 3620 hours, and the corrosion resistance was optimal.

[0096] Example 55

[0097] The modified waterborne polyurethane and the corrosion inhibitor were prepared according to the method of Example 37.

[0098] Preparation of modified graphene oxide: 120 mg of graphene oxide, catalyst diisopropylcarbodiimide and melamine were ultrasonically dispersed in 100 ml of N,N-dimethylformamide for 1 hour to obtain a suspension; the suspension was heated to 80°C and stirred for 10 hours to obtain a brown suspension; the brown suspension was rinsed three times with N,N-dimethylformamide and 100°C boiling water, and then dried at 70°C for 20 hours to obtain the modified graphene oxide; the mass ratio of graphene oxide, catalyst and melamine was 1:0.5:2.5; the graphene oxide was in the form of flakes.

[0099] Preparation of corrosion-resistant water-based paint: 70 parts of epoxy resin and modified water-based polyurethane are added to deionized water under stirring conditions and mixed evenly to obtain a slurry; the stirring speed is 520 rpm; the stirring time is 31 minutes; 5 parts of zinc phosphate particles and 7 parts of modified graphene oxide are added to the slurry, and stirring is continued at a speed of 315 rpm for 60 minutes to obtain a mixture; 1.5 parts of defoaming agent polydimethylsiloxane, 1.2 parts of thickener polyacrylamide, dispersant quinacridone and 5 parts of corrosion inhibitor are added to the mixture, and stirring is carried out at a speed of 540 rpm for 35 minutes to obtain a corrosion-resistant water-based paint; the ratio of epoxy resin to modified water-based polyurethane is 1.8:1.2; the hard segment content of the modified water-based polyurethane is 45%; the ratio of quinacridone to modified graphene oxide is 1.8:7.

[0100] Examples 56-65

[0101] Referring to the preparation method and parameter conditions of Example 55, the specific differences are shown in Table 8.

[0102] Table 8 Specific preparation parameters of Examples 56-65

[0103] Example Catalyst type Ratio of graphene oxide, catalyst and melamine Suspension heating temperature / ℃ Ratio of quinacridone and modified graphene oxide Example 56 1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide 1：0.5：2.5 80 1.8：7 Example 57 N,N-di-tert-butylcarbodiimide 1：0.5：2.5 80 1.8：7 Example 58 1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide 1：0.5：2.8 80 1.8：7 Example 59 1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide 1：0.5：3.1 80 1.8：7 Example 60 1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide 1：0.5：3.5 80 1.8：7 Example 61 1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide 1：0.5：2.8 85 1.8：7 Example 62 1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide 1：0.5：2.8 90 1.8：7 Example 63 1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide 1：0.5：2.8 100 1.8：7 Example 64 1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide 1：0.5：2.8 90 1.8：9 Example 65 1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide 1：0.5：2.8 90 1.8：12

[0104] Comparative Example 2

[0105] A corrosion-resistant water-based paint was prepared according to the method of Example 1, except that the graphene oxide was not modified.

[0106] Example 66 Corrosion Resistance Test

[0107] Acid resistance test: Test the acid resistance of water-based paint in 50g / L sulfuric acid solution for 192h according to Method A of GB / T9274-1988 standard;

[0108] Alkali resistance test: Test the alkali resistance of water-based paint in 50g / L sodium hydroxide solution for 168h according to Method A of GB / T9274-1988 standard;

[0109] Salt spray resistance: The salt spray resistance of water-based paint was tested according to GB / T1771-2007. The coating thickness was 100±10μm. The time for blistering, peeling, rusting, and cracking to occur was tested. The results are shown in Table 9.

[0110] Table 9 Corrosion resistance test of Examples 52, 55-65, and Comparative Example 2

[0111] Example Acid resistance Alkali resistance Salt spray resistance / h Example 52 No abnormalities No abnormalities 3654 Example 55 No abnormalities No abnormalities 3624 Example 56 No abnormalities No abnormalities 3670 Example 57 A few rust spots A few rust spots 3612 Example 58 No abnormalities No abnormalities 3675 Example 59 No abnormalities No abnormalities 3670 Example 60 A few rust spots A few rust spots 3658 Example 61 No abnormalities No abnormalities 3678 Example 62 No abnormalities No abnormalities 3687 Example 63 No abnormalities No abnormalities 3682 Example 64 No abnormalities No abnormalities 3691 Example 65 No abnormalities No abnormalities 3684 Comparative Example 2 Obvious rust spots Obvious rust spots 3018

[0112] Table 9 shows that in Examples 52, 55-57, when the catalyst type was varied and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide was used as the catalyst, the resulting urea was water-soluble and easily separated and removed, simplifying the post-processing and purification process. Furthermore, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide exhibited excellent stability and reactivity, resulting in the most stable modified graphene, which exhibited the best corrosion resistance when applied to water-based paints. In Examples 56, 58-60, the mass ratio of graphene oxide, catalyst, and melamine was varied. Excessive melamine content can lead to self-crosslinking of the graphene oxide chains, which can induce precipitation of the graphene oxide and disrupt its dispersibility in the solution. This, in turn, affects the structural uniformity and integrity of the modified graphene oxide, compromising its corrosion resistance. In Example 58, the material produced with a mass ratio of graphene oxide, catalyst, and melamine of 1:0.5:2.8 exhibited the best corrosion resistance. In Examples 58 and 61-63, if the suspension heating temperature is too high, melamine may decompose, and the resulting byproducts may adversely affect the performance of the modified graphene oxide and serve as a channel for the penetration of corrosive media, reducing the corrosion resistance of the coating. If the suspension heating temperature is too low, the graphene oxide has poor dispersibility and easily forms aggregates, which in turn affects its corrosion resistance. In Example 62, the optimal heating temperature is 90°C. In Examples 62 and 64-65, if the quinacridone ratio is too high, the barrier effect of the modified graphene oxide in the coating will be weakened, allowing the corrosive media to penetrate more easily into the coating. If the quinacridone ratio is too low, the corrosion resistance of the resulting water-based paint will be limited. In Example 64, modified graphene oxide was produced using 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide as a catalyst, a mass ratio of graphene oxide, catalyst, and melamine of 1:0.5:2.8, and a suspension heating temperature of 90°C. When the ratio of quinacridone to modified graphene oxide was 1.8:9, the resulting corrosion-resistant water-based paint exhibited the best corrosion resistance, showing no abnormalities after immersion in a 50 g / L sulfuric acid solution for 192 hours and in a 50 g / L sodium hydroxide solution for 168 hours. In a salt spray resistance test, the paint showed no blistering, flaking, rusting, or cracking for 3691 hours. In Comparative Example 2, unmodified graphene oxide was used, which was prone to agglomeration and phase separation, resulting in a water-based paint with poor corrosion resistance.

[0113] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A process for preparing a corrosion-resistant water-based paint, characterized in that: The preparation process of the corrosion-resistant water-based paint is as follows: Adding epoxy resin and modified waterborne polyurethane to deionized water under stirring conditions and mixing uniformly to obtain a slurry; the stirring speed is 450-550 rpm; the stirring time is 25-35 minutes; zinc phosphate particles and modified graphene oxide are added to the slurry, and stirring is continued at a speed of 300-350 rpm for 55-65 minutes to obtain a mixture; adding a defoamer, a thickener, a dispersant, and a corrosion inhibitor to the mixture, and stirring at a speed of 500-600 rpm for 30-40 minutes to obtain the corrosion-resistant waterborne paint; The modified waterborne polyurethane is obtained by graphene oxide through prepolymerization, chain extension and neutralization; the prepolymerization temperature is 70-75°C; the chain extension temperature is 85-95°C; and the neutralization temperature is 50-60°C. The modified graphene oxide is obtained by reacting the graphene oxide, a catalyst and melamine in N,N-dimethylformamide; the mass ratio of the graphene oxide, the catalyst and the melamine is 1:0.5:2.5-3.5; The corrosion inhibitor comprises sodium oleate, aramid nanofibers and zeolite particles; the ratio of the sodium oleate to the aramid nanofibers is 1-5:1; the ratio of the sodium oleate to the zeolite particles is 1-4:1.

2.

2. The process for preparing a corrosion-resistant water-based paint according to claim 1, wherein: The ratio of the epoxy resin to the modified waterborne polyurethane is 1.5-2.1:1.

2.

3. The process for preparing a corrosion-resistant water-based paint according to claim 1, wherein: The hard segment content of the modified waterborne polyurethane is 35%-55%.

4. The process for preparing a corrosion-resistant water-based paint according to claim 1, wherein: The dispersant is quinacridone; the ratio of the quinacridone to the modified graphene oxide is 1.8:7-12.

5. The process for preparing a corrosion-resistant water-based paint according to claim 1, characterized in that: The preparation process of the modified waterborne polyurethane is as follows: adding the graphene oxide to the deionized water and ultrasonically crushing it to obtain a suspension; the concentration of the graphene oxide in the suspension is 1.2-1.8wt%; adding isophorone diisocyanate and the suspension into a three-necked flask and stirring for 0.8h to obtain a mixed solution I; adding PPG-2000 and 1.5-2.5wt% of stannous octoate to the mixed solution I to obtain a prepolymer; uniformly mixing ethylene glycol and acetone, and then dropwise adding the mixture to the prepolymer to react for 1.5h to obtain a mixture II; dissolving 2,2-dihydroxymethylpropionic acid in N-methylpyrrolidone to obtain a mixture III; dropping the mixture III into the mixture II to obtain a mixture IV; adding ammonia water to the mixture IV to carry out the neutralization reaction, reacting for 20 minutes, and then cooling to room temperature to obtain the modified waterborne polyurethane.

6. The process for preparing a corrosion-resistant water-based paint according to claim 1, characterized in that: The preparation process of the modified graphene oxide is as follows: ultrasonically dispersing the graphene oxide, a catalyst, and melamine in N,N-dimethylformamide for 1 hour to obtain a suspension; heating the suspension to 80-100° C. and stirring for 10 hours to obtain a brown suspension; rinsing the brown suspension three times with N,N-dimethylformamide and 100° C. boiling water, and then drying at 70° C. for 20 hours to obtain the modified graphene oxide.

7. The process for preparing a corrosion-resistant water-based paint according to claim 6, characterized in that: The catalyst is one of dicyclohexylcarbodiimide, diisopropylcarbodiimide, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and N,N-di-tert-butylcarbodiimide.

8. The process for preparing a corrosion-resistant water-based paint according to claim 6, characterized in that: The graphene oxide is in a flake shape.

9. The process for preparing a corrosion-resistant water-based paint according to claim 1, characterized in that: The preparation process of the corrosion inhibitor is as follows: 1 / 3 of the total weight of the sodium oleate and the aramid nanofiber are mixed and stirred in deionized water for 20-35 minutes to obtain component A; the remaining 2 / 3 of the sodium oleate and the zeolite particles are mixed and stirred in deionized water for 15-20 hours to obtain component B; and the components A and B are mixed to obtain the corrosion inhibitor.

10. A corrosion-resistant water-based paint prepared by the process of claim 1, characterized in that: The raw materials for producing the corrosion-resistant water-based paint include epoxy resin, modified water-based polyurethane, corrosion inhibitor, modified graphene oxide and quinacridone.

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