Water-based nano-graphene anticorrosive paint and preparation method thereof
By modifying graphene oxide in multiple steps, a modified acrylic emulsion was prepared, which solved the problem of poor graphene dispersion in water-based anti-corrosion coatings and improved the coating's high-efficiency anti-corrosion performance and mechanical properties.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- YUNNAN OPEN UNIV
- Filing Date
- 2026-01-16
- Publication Date
- 2026-05-12
AI Technical Summary
The poor dispersion performance of graphene in existing water-based anti-corrosion coatings results in insufficient anti-corrosion performance, especially in harsh corrosive environments where the service life is short.
By modifying graphene oxide in multiple steps, introducing acyl chloride, 6-aminoisoquinoline and quaternary ammonium salts, a modified acrylic emulsion is formed and uniformly dispersed in waterborne epoxy resin to form a dense physical barrier, thereby enhancing the coating's impermeability and corrosion resistance.
Modified graphene is uniformly dispersed in the coating, forming a dense physical barrier that significantly improves the coating's impermeability and long-term corrosion resistance, enhances its hardness, wear resistance, and impact resistance, and is environmentally friendly and non-toxic.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of water-based anti-corrosion coatings, specifically to a water-based nano-graphene anti-corrosion coating and its preparation method. Background Technology
[0002] Metallic materials are indispensable in modern industrial production and daily life, possessing excellent mechanical and processing properties, and are widely used in industrial production, infrastructure construction, transportation, and other fields. However, metallic materials are susceptible to corrosion due to environmental factors during use. This ubiquitous natural phenomenon not only leads to performance degradation and shortened service life of metallic materials, causing significant economic losses, but also poses substantial safety hazards. Among these, anti-corrosion coatings, with their advantages of convenient application, controllable cost, wide applicability, and direct protective effect, have become the most widely used method for metal corrosion protection.
[0003] Traditional anti-corrosion coatings mostly use organic solvents as dispersion media, containing a large amount of volatile organic compounds (VOCs). During production and application, these compounds can cause chronic damage to the respiratory and nervous systems of operators, while also contributing to environmental pollution, contradicting green environmental protection principles and sustainable development requirements. With increasing environmental awareness, developing low-VOC, environmentally friendly water-based anti-corrosion coatings has become an inevitable trend in the industry. However, residual hydrophilic groups and surfactants in existing water-based anti-corrosion coatings can form polar channels, facilitating the penetration of water, oxygen, and corrosive ions. This results in poor shielding ability against corrosive media and insufficient anti-corrosion performance, especially in harsh corrosive environments such as marine and chemical plants, leading to a shorter service life.
[0004] Nano-graphene, as a two-dimensional layered nanomaterial, possesses excellent mechanical properties, chemical stability, and barrier properties. When introduced into anti-corrosion coatings, its layered structure can form a continuous barrier layer within the coating, effectively isolating corrosive media such as water and oxygen, significantly improving the coating's anti-corrosion performance. Chinese patent application CN110157289A discloses a water-based graphene anti-corrosion coating, comprising a water-based resin, graphene dispersion, filler, solvent, defoamer, polytetrafluoroethylene, sodium hexaphosphate metaate, leveling agent, curing agent, dimethyl dicarbonate, and deionized water. This water-based graphene anti-corrosion coating features energy saving, environmental friendliness, strong water resistance, and good anti-corrosion performance. However, the graphene and filler added to the coating have poor dispersion properties and are prone to agglomeration, affecting the coating's anti-corrosion performance. Chinese patent application CN109517481A discloses a method for preparing a graphene-containing waterborne epoxy anticorrosive coating. The method involves intercalating and oxidizing ordinary natural flake graphite, then dissolving it in deionized water and ultrasonically exfoliating the flakes to obtain an aqueous solution of graphene oxide. Graphene oxide is then added as a filler to an aqueous epoxy resin, and additives are added to obtain the graphene-containing waterborne epoxy composite coating. This method is simple to operate, consumes little energy, has low cost, high production efficiency, and is easy to industrialize. However, while oxidizing graphene to form graphene oxide can improve the dispersion of graphene in waterborne coatings to some extent, the compatibility between graphene oxide and the polymer still has defects, affecting the anticorrosive effect of the coating after drying and its stable storage properties.
[0005] Therefore, developing a water-based anti-corrosion coating with uniform graphene dispersion, excellent anti-corrosion performance, and superior overall performance is of great practical significance. Summary of the Invention
[0006] (a) Technical problems to be solved
[0007] To address the shortcomings of existing technologies, this invention provides an aqueous nano-graphene anticorrosive coating and its preparation method, which solves the problem of the coating's generally poor corrosion resistance.
[0008] (II) Technical Solution
[0009] To achieve the above objectives, this invention discloses an aqueous nano-graphene anti-corrosion coating, comprising the following components by weight: 32-45 parts of aqueous epoxy resin, 21-30 parts of modified acrylic emulsion, 5-9 parts of curing agent, 3-5 parts of film-forming aid, 0.5-1.2 parts of thickener, 0.1-0.3 parts of defoamer, 0.3-0.5 parts of dispersant, 0.1-0.3 parts of leveling agent, and 18-25 parts of deionized water.
[0010] Preferably, the waterborne epoxy resin is composed of waterborne epoxy resin E51 and waterborne epoxy resin E44 in a mass ratio of 3:1.
[0011] Preferably, the film-forming aid is composed of propylene glycol methyl ether acetate and dodecyl alcohol ester in a mass ratio of 2:1.
[0012] Preferably, the curing agent is a water-based modified amine curing agent.
[0013] Furthermore, the water-based modified amine curing agent is an aliphatic polyamide curing agent.
[0014] Preferably, the thickener is a nonionic polyurethane thickener.
[0015] Furthermore, the nonionic polyurethane thickener is RM-8W thickener.
[0016] Preferably, the defoamer is an organosilicone defoamer.
[0017] Furthermore, the silicone defoamer is BYK-024.
[0018] Preferably, the dispersant is a polycarboxylate dispersant.
[0019] Furthermore, the polycarboxylate dispersant is SN-5040.
[0020] Preferably, the leveling agent is an acrylate leveling agent.
[0021] Furthermore, the leveling agent is BYK-358N.
[0022] Preferably, the preparation method of the modified acrylic emulsion includes the following steps:
[0023] S1. Graphene oxide is ultrasonically dispersed in thionyl chloride, heated, and reacted. After the reaction is complete, the mixture is filtered, washed with petroleum ether, and dried to obtain acyl-chromium graphene.
[0024] S2. Acyl-chlorographene was ultrasonically dispersed in dichloromethane. After uniform dispersion, 6-aminoisoquinoline and triethylamine were added, stirred and mixed, and the reaction was carried out. After the reaction was completed, the mixture was filtered, washed with sodium bicarbonate first, then washed with deionized water until neutral, and dried to obtain modified graphene.
[0025] S3. The modified graphene was ultrasonically dispersed in N,N-dimethylformamide, 4-chloromethylstyrene was added, the mixture was stirred and heated to allow the reaction to proceed. After the reaction was completed, the mixture was filtered, washed with ethanol, and dried to obtain quaternary ammonium salt modified graphene.
[0026] S4. Mix deionized water and emulsifier evenly, then add methyl methacrylate, butyl acrylate, styrene, hexafluorobutyl acrylate, dodecafluoroheptyl methacrylate, double bond phosphate monomer, quaternary ammonium salt modified graphene, and vinyltriethoxysilane and mix evenly. Heat and stir, add initiator, and react. After the reaction is complete, filter and discharge to obtain modified acrylic emulsion.
[0027] Preferably, the mass ratio of graphene oxide to sulfoxide in S1 is 100:6000-8000, the reaction temperature is 70-80℃, and the reaction time is 12-16h.
[0028] Preferably, the mass ratio of acyl-chlorographene, dichloromethane, 6-aminoisoquinoline, and triethylamine in S2 is 100:2400-2500:38-55:3-5, the reaction temperature is 25-35℃, and the reaction time is 8-10h.
[0029] Preferably, the mass ratio of modified graphene, N,N-dimethylformamide, and 4-chloromethylstyrene in S3 is 100:1500-1800:120-150, the reaction temperature is 75-85℃, and the reaction time is 5-8h.
[0030] Preferably, in step S4, the mass ratio of deionized water, emulsifier, methyl methacrylate, butyl acrylate, styrene, hexafluorobutyl acrylate, dodecafluoroheptyl methacrylate, double-bonded phosphate monomer, quaternary ammonium salt modified graphene, vinyltriethoxysilane, and initiator is 480-550:8-15:65-80:100:20-30:5-8:3-5:2-4:4-7:1-2:2-3, the reaction temperature is 70-80℃, and the reaction time is 4-5 hours.
[0031] Furthermore, the emulsifier is composed of sodium dodecyl sulfate and alkylphenol polyoxyethylene ether in a mass ratio of 2:1.
[0032] Preferably, the initiator in S4 is ammonium persulfate.
[0033] Preferably, the double-bonded phosphate monomer in S4 is double-bonded polyethylene glycol methacrylate phosphate.
[0034] A method for preparing an aqueous nano-graphene anticorrosive coating includes the following steps:
[0035] Step 1: Stir deionized water, dispersant, and defoamer at a speed of 600-800 r / min for 5-8 min to obtain a dispersion.
[0036] Step 2: Add waterborne epoxy resin, modified acrylic emulsion, film-forming aid, and thickener to the dispersion, and stir and mix at a speed of 300-400 r / min for 10-15 min. Add leveling agent and curing agent, stir and mix for 20-30 min, and pass through a 120 mesh sieve to obtain waterborne nano-graphene anti-corrosion coating.
[0037] (iii) Beneficial technical effects
[0038] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0039] (1) In this invention, graphene oxide is modified in multiple steps. First, acyl chloride is introduced onto the graphene oxide. The acyl chloride graphene reacts with the amino group on 6-aminoisoquinoline to obtain modified graphene. The modified graphene reacts with 4-chloromethylstyrene to introduce quaternary ammonium salt and alkenyl group to obtain quaternary ammonium salt modified graphene. The quaternary ammonium salt modified graphene is polymerized with methyl methacrylate, butyl acrylate, styrene, hexafluorobutyl acrylate, dodecafluoroheptyl methacrylate, double bond phosphate monomer, and vinyltriethoxysilane under the action of an initiator to obtain modified acrylic emulsion. Graphene oxide is introduced into the acrylic emulsion framework in a chemically bonded manner, which can be uniformly and stably dispersed in the emulsion, effectively avoiding agglomeration and enabling long-term storage. The two-dimensional sheet structure of graphene can form a dense physical barrier in the coating, effectively blocking the penetration of corrosive media such as water, oxygen, and chloride ions, and greatly improving the coating's impermeability and long-term corrosion resistance. Furthermore, the uniformly dispersed nano-graphene can effectively transfer and disperse stress, playing a nano-reinforcing role and improving the hardness, wear resistance and impact resistance of the coating.
[0040] (2) In this invention, a composite of waterborne epoxy resin and modified acrylic emulsion is used. The epoxy resin provides excellent adhesion and chemical stability, while the modified acrylic emulsion introduces functional groups such as fluorine, silicon, and phosphate esters, which enhances the hydrophobicity, weather resistance, and interfacial bonding of the coating with the substrate, greatly improving the adhesion of the coating to the substrate. The two work synergistically to form an interpenetrating polymer network, further enhancing the anti-permeability and mechanical properties of the paint film. The prepared coating can form a strong and dense composite paint film on the substrate surface, with good anti-corrosion effect.
[0041] (3) In this invention, the quaternary ammonium salt combines with the negatively charged metal surface through the positively charged groups in the molecule to form a dense adsorption film, which blocks the corrosive medium and achieves antibacterial and anti-corrosion effects. The phosphate ester group can form a coordination bond with the metal substrate to play a corrosion inhibition role, and the double-bonded phosphate ester monomer helps to improve the adhesion and water resistance of the coating to the substrate. The fluorocarbon chain and siloxane group can reduce the surface energy of the paint film, form a low surface energy protective layer, reduce the adsorption of corrosive media, and achieve long-term anti-corrosion. Deionized water is used as the main dispersion medium, which is green and environmentally friendly and has good safety performance during production and transportation. The prepared coating has excellent defoaming effect and smooth film-forming performance. It can form a dense and stable coating structure on the substrate, effectively blocking the intrusion of external moisture, oxygen and corrosive media, thereby protecting the substrate from damage. It has good anti-corrosion effect, excellent mechanical properties, and is easy to brush, roll or spray. Detailed Implementation
[0042] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.
[0043] Example 1
[0044] A modified acrylic emulsion, the preparation method of which includes the following steps:
[0045] S1. Graphene oxide and thionyl chloride in a mass ratio of 100:6000 are ultrasonically dispersed evenly, heated to 70°C and reacted for 16 hours. After the reaction is completed, the mixture is filtered, washed with petroleum ether, and dried to obtain acyl-chlorographene.
[0046] S2. Acyl-chlorographene was ultrasonically dispersed in dichloromethane. After uniform dispersion, 6-aminoisoquinoline and triethylamine were added, wherein the mass ratio of acyl-chlorographene, dichloromethane, 6-aminoisoquinoline and triethylamine was 100:2400:38:3. The mixture was stirred and reacted at 25°C for 10 hours. After the reaction was completed, the mixture was filtered, washed first with sodium bicarbonate, then washed with deionized water until neutral, and dried to obtain modified graphene.
[0047] S3. Modified graphene was ultrasonically dispersed in N,N-dimethylformamide, and 4-chloromethylstyrene was added, wherein the mass ratio of modified graphene, N,N-dimethylformamide, and 4-chloromethylstyrene was 100:1500:120. The mixture was stirred and heated to 75°C for 8 hours. After the reaction was completed, the mixture was filtered, washed with ethanol, and dried to obtain quaternary ammonium salt modified graphene.
[0048] S4. After mixing deionized water and emulsifier evenly, add methyl methacrylate, butyl acrylate, styrene, hexafluorobutyl acrylate, dodecafluoroheptyl methacrylate, double-bonded polyethylene glycol methacrylate, quaternary ammonium salt modified graphene, and vinyltriethoxysilane and mix evenly. Heat and stir, then add ammonium persulfate as an initiator. The mass ratio of deionized water, emulsifier, methyl methacrylate, butyl acrylate, styrene, hexafluorobutyl acrylate, dodecafluoroheptyl methacrylate, double-bonded polyethylene glycol methacrylate, quaternary ammonium salt modified graphene, vinyltriethoxysilane, and ammonium persulfate is 480:8:65:100:20:5:3:2:4:1:2. The reaction is carried out at 70℃ for 5 hours. After the reaction is completed, filter and discharge to obtain modified acrylic emulsion.
[0049] Example 2
[0050] A modified acrylic emulsion, the preparation method of which includes the following steps:
[0051] S1. Graphene oxide and thionyl chloride in a mass ratio of 100:7000 are ultrasonically dispersed evenly, heated to 75°C and reacted for 15 hours. After the reaction is completed, the mixture is filtered, washed with petroleum ether, and dried to obtain acyl-chlorographene.
[0052] S2. Acyl-chlorographene was ultrasonically dispersed in dichloromethane. After uniform dispersion, 6-aminoisoquinoline and triethylamine were added, wherein the mass ratio of acyl-chlorographene, dichloromethane, 6-aminoisoquinoline and triethylamine was 100:2450:45:4. The mixture was stirred and reacted at 30°C for 9 hours. After the reaction was completed, the mixture was filtered, washed first with sodium bicarbonate, then washed with deionized water until neutral, and dried to obtain modified graphene.
[0053] S3. Modified graphene was ultrasonically dispersed in N,N-dimethylformamide, and 4-chloromethylstyrene was added, wherein the mass ratio of modified graphene, N,N-dimethylformamide, and 4-chloromethylstyrene was 100:1600:135. The mixture was stirred and heated to 80°C for 6 hours. After the reaction was completed, the mixture was filtered, washed with ethanol, and dried to obtain quaternary ammonium salt modified graphene.
[0054] S4. After mixing deionized water and emulsifier evenly, add methyl methacrylate, butyl acrylate, styrene, hexafluorobutyl acrylate, dodecafluoroheptyl methacrylate, double-bonded polyethylene glycol methacrylate, quaternary ammonium salt modified graphene, and vinyltriethoxysilane and mix evenly. Heat and stir, then add ammonium persulfate as an initiator. The mass ratio of deionized water, emulsifier, methyl methacrylate, butyl acrylate, styrene, hexafluorobutyl acrylate, dodecafluoroheptyl methacrylate, double-bonded polyethylene glycol methacrylate, quaternary ammonium salt modified graphene, vinyltriethoxysilane, and ammonium persulfate is 520:12:72:100:25:7:4:3:5:1.4:2.5. The reaction takes place at 75°C for 4.5 hours. After the reaction is complete, filter and discharge to obtain the modified acrylic emulsion.
[0055] Example 3
[0056] A modified acrylic emulsion, the preparation method of which includes the following steps:
[0057] S1. Graphene oxide and thionyl chloride in a mass ratio of 100:8000 are ultrasonically dispersed evenly, heated to 80°C and reacted for 12 hours. After the reaction is completed, the mixture is filtered, washed with petroleum ether, and dried to obtain acyl-chlorographene.
[0058] S2. Acyl-chlorographene was ultrasonically dispersed in dichloromethane. After uniform dispersion, 6-aminoisoquinoline and triethylamine were added, wherein the mass ratio of acyl-chlorographene, dichloromethane, 6-aminoisoquinoline and triethylamine was 100:2500:55:5. The mixture was stirred and mixed, and the reaction was carried out at 35°C for 8 hours. After the reaction was completed, the mixture was filtered, washed first with sodium bicarbonate, then washed with deionized water until neutral, and dried to obtain modified graphene.
[0059] S3. Modified graphene was ultrasonically dispersed in N,N-dimethylformamide, and 4-chloromethylstyrene was added, wherein the mass ratio of modified graphene, N,N-dimethylformamide, and 4-chloromethylstyrene was 100:1800:150. The mixture was stirred and heated to 85°C for 5 hours. After the reaction was completed, the mixture was filtered, washed with ethanol, and dried to obtain quaternary ammonium salt modified graphene.
[0060] S4. After mixing deionized water and emulsifier evenly, add methyl methacrylate, butyl acrylate, styrene, hexafluorobutyl acrylate, dodecafluoroheptyl methacrylate, double-bonded polyethylene glycol methacrylate, quaternary ammonium salt modified graphene, and vinyltriethoxysilane and mix evenly. Heat and stir, then add ammonium persulfate as an initiator. The mass ratio of deionized water, emulsifier, methyl methacrylate, butyl acrylate, styrene, hexafluorobutyl acrylate, dodecafluoroheptyl methacrylate, double-bonded polyethylene glycol methacrylate, quaternary ammonium salt modified graphene, vinyltriethoxysilane, and ammonium persulfate is 550:15:80:100:30:8:5:4:7:2:3. The reaction is carried out at 80℃ for 4 hours. After the reaction is completed, filter and discharge to obtain modified acrylic emulsion.
[0061] Example 4
[0062] A water-based nano-graphene anti-corrosion coating, the preparation method of which includes the following steps:
[0063] (1) Weigh the raw materials by weight, including 32 parts of waterborne epoxy resin, 21 parts of modified acrylic emulsion, 5 parts of curing agent aliphatic polyamide curing agent, 3 parts of film-forming aid, 0.5 parts of RM-8W thickener, 0.1 parts of organosilicon defoamer BYK-024, 0.3 parts of dispersant SN-5040, 0.1 parts of leveling agent BYK-358N, and 18 parts of deionized water. The waterborne epoxy resin is composed of waterborne epoxy resin E51 and waterborne epoxy resin E44 in a mass ratio of 3:1, and the film-forming aid is composed of propylene glycol methyl ether acetate and dodecyl alcohol ester in a mass ratio of 2:1.
[0064] (2) Deionized water, dispersant SN-5040 and silicone defoamer BYK-024 were stirred at a speed of 600 r / min for 8 min to obtain a dispersion.
[0065] (3) Add waterborne epoxy resin, modified acrylic emulsion, film-forming aid, and RM-8W thickener to the dispersion, stir and mix at a speed of 300r / min for 15min, add leveling agent, curing agent, aliphatic polyamide curing agent, stir and mix for 20min, and pass through a 120-mesh sieve to obtain waterborne nano-graphene anti-corrosion coating.
[0066] The preparation method of the modified acrylic emulsion in this embodiment is completely consistent with the preparation method of the modified acrylic emulsion in Example 1.
[0067] Example 5
[0068] A water-based nano-graphene anti-corrosion coating, the preparation method of which includes the following steps:
[0069] (1) Weigh the raw materials by weight, including 35 parts of waterborne epoxy resin, 25 parts of modified acrylic emulsion, 7 parts of curing agent aliphatic polyamide curing agent, 4 parts of film-forming aid, 1 part of RM-8W thickener, 0.2 parts of organosilicon defoamer BYK-024, 0.4 parts of dispersant SN-5040, 0.2 parts of leveling agent BYK-358N, and 22 parts of deionized water. The waterborne epoxy resin is composed of waterborne epoxy resin E51 and waterborne epoxy resin E44 in a mass ratio of 3:1, and the film-forming aid is composed of propylene glycol methyl ether acetate and dodecyl alcohol ester in a mass ratio of 2:1.
[0070] (2) Deionized water, dispersant SN-5040 and silicone defoamer BYK-024 were stirred at a speed of 700 r / min for 7 min to obtain a dispersion.
[0071] (3) Add waterborne epoxy resin, modified acrylic emulsion, film-forming aid, and RM-8W thickener to the dispersion, stir and mix at a speed of 350 r / min for 14 min, add leveling agent, curing agent, aliphatic polyamide curing agent, stir and mix for 28 min, and pass through a 120 mesh sieve to obtain waterborne nano-graphene anti-corrosion coating.
[0072] The preparation method of the modified acrylic emulsion in this embodiment is completely consistent with the preparation method of the modified acrylic emulsion in Example 2.
[0073] Example 6
[0074] A water-based nano-graphene anti-corrosion coating, the preparation method of which includes the following steps:
[0075] (1) Weigh the raw materials by weight, including 43 parts of waterborne epoxy resin, 28 parts of modified acrylic emulsion, 8 parts of curing agent aliphatic polyamide curing agent, 4.5 parts of film-forming aid, 1 part of RM-8W thickener, 0.25 parts of organosilicon defoamer BYK-024, 0.42 parts of dispersant SN-5040, 0.25 parts of leveling agent BYK-358N, and 22 parts of deionized water. The waterborne epoxy resin is composed of waterborne epoxy resin E51 and waterborne epoxy resin E44 in a mass ratio of 3:1, and the film-forming aid is composed of propylene glycol methyl ether acetate and dodecyl alcohol ester in a mass ratio of 2:1.
[0076] (2) Deionized water, dispersant SN-5040 and silicone defoamer BYK-024 were stirred at a speed of 700 r / min for 7 min to obtain a dispersion.
[0077] (3) Add waterborne epoxy resin, modified acrylic emulsion, film-forming aid, and RM-8W thickener to the dispersion, stir and mix at a speed of 350 r / min for 14 min, add leveling agent, curing agent, aliphatic polyamide curing agent, stir and mix for 28 min, and pass through a 120 mesh sieve to obtain waterborne nano-graphene anti-corrosion coating.
[0078] The preparation method of the modified acrylic emulsion in this embodiment is completely consistent with the preparation method of the modified acrylic emulsion in Example 2.
[0079] Example 7
[0080] A water-based nano-graphene anti-corrosion coating, the preparation method of which includes the following steps:
[0081] (1) Weigh the raw materials by weight, including 45 parts of waterborne epoxy resin, 30 parts of modified acrylic emulsion, 9 parts of curing agent aliphatic polyamide curing agent, 5 parts of film-forming aid, 1.2 parts of RM-8W thickener, 0.3 parts of organosilicon defoamer BYK-024, 0.5 parts of dispersant SN-5040, 0.3 parts of leveling agent BYK-358N, and 25 parts of deionized water. The waterborne epoxy resin is composed of waterborne epoxy resin E51 and waterborne epoxy resin E44 in a mass ratio of 3:1, and the film-forming aid is composed of propylene glycol methyl ether acetate and dodecyl alcohol ester in a mass ratio of 2:1.
[0082] (2) Deionized water, dispersant SN-5040 and silicone defoamer BYK-024 were stirred at a speed of 800 r / min for 5 min to obtain a dispersion.
[0083] (3) Add waterborne epoxy resin, modified acrylic emulsion, film-forming aid, and RM-8W thickener to the dispersion, stir and mix at a speed of 400r / min for 10min, add leveling agent, curing agent, aliphatic polyamide curing agent, stir and mix for 30min, and pass through a 120-mesh sieve to obtain waterborne nano-graphene anti-corrosion coating.
[0084] The preparation method of the modified acrylic emulsion in this embodiment is completely consistent with the preparation method of the modified acrylic emulsion in Example 3.
[0085] Comparative Example 1
[0086] A water-based nano-graphene anti-corrosion coating, the preparation method of which includes the following steps:
[0087] (1) Weigh the raw materials by weight, including 43 parts of waterborne epoxy resin, 28 parts of modified acrylic emulsion, 8 parts of curing agent aliphatic polyamide curing agent, 4.5 parts of film-forming aid, 1 part of RM-8W thickener, 0.25 parts of organosilicon defoamer BYK-024, 0.42 parts of dispersant SN-5040, 0.25 parts of leveling agent BYK-358N, and 22 parts of deionized water. The waterborne epoxy resin is composed of waterborne epoxy resin E51 and waterborne epoxy resin E44 in a mass ratio of 3:1, and the film-forming aid is composed of propylene glycol methyl ether acetate and dodecyl alcohol ester in a mass ratio of 2:1.
[0088] (2) Deionized water, dispersant SN-5040 and silicone defoamer BYK-024 were stirred at a speed of 700 r / min for 7 min to obtain a dispersion.
[0089] (3) Add waterborne epoxy resin, modified acrylic emulsion, film-forming aid, and RM-8W thickener to the dispersion, stir and mix at a speed of 350 r / min for 14 min, add leveling agent, curing agent, aliphatic polyamide curing agent, stir and mix for 28 min, and pass through a 120 mesh sieve to obtain waterborne nano-graphene anti-corrosion coating.
[0090] The preparation method of the modified acrylic emulsion used in this comparative example includes the following steps:
[0091] S1. Graphene oxide is ultrasonically dispersed in anhydrous ethanol. After uniform dispersion, γ-(methacryloyloxy)propyltrimethoxysilane is added, wherein the mass ratio of graphene oxide, anhydrous ethanol and γ-(methacryloyloxy)propyltrimethoxysilane is 100:1600:38. The mixture is stirred and reacted. After the reaction is completed, the mixture is centrifuged, washed with deionized water, and dried to obtain alkenyl graphene.
[0092] S2. After mixing deionized water and emulsifier evenly, add methyl methacrylate, butyl acrylate, styrene, hexafluorobutyl acrylate, dodecafluoroheptyl methacrylate, double-bonded polyethylene glycol methacrylate phosphate, alkenyl graphene, and vinyltriethoxysilane and mix evenly. Heat and stir, then add ammonium persulfate as an initiator. The mass ratio of deionized water, emulsifier, methyl methacrylate, butyl acrylate, styrene, hexafluorobutyl acrylate, dodecafluoroheptyl methacrylate, double-bonded polyethylene glycol methacrylate phosphate, alkenyl graphene, vinyltriethoxysilane, and ammonium persulfate is 520:12:72:100:25:7:4:3:5:1.4:2.5. The reaction is carried out at 75℃ for 4.5 hours. After the reaction is completed, filter and discharge to obtain modified acrylic emulsion.
[0093] Comparative Example 2
[0094] A water-based nano-graphene anti-corrosion coating, the preparation method of which includes the following steps:
[0095] (1) Weigh the raw materials by weight, including 70 parts of waterborne epoxy resin, 27 parts of acrylic emulsion, 1 part of graphene oxide, 8 parts of aliphatic polyamide curing agent, 4.5 parts of film-forming aid, 1 part of RM-8W thickener, 0.25 parts of organosilicon defoamer BYK-024, 0.42 parts of dispersant SN-5040, 0.25 parts of leveling agent BYK-358N, and 22 parts of deionized water. The waterborne epoxy resin is composed of waterborne epoxy resin E51 and waterborne epoxy resin E44 in a mass ratio of 3:1, and the film-forming aid is composed of propylene glycol methyl ether acetate and dodecyl alcohol ester in a mass ratio of 2:1.
[0096] (2) Deionized water, dispersant SN-5040 and silicone defoamer BYK-024 were stirred at a speed of 700 r / min for 7 min to obtain a dispersion.
[0097] (3) Add waterborne epoxy resin, acrylic emulsion, graphene oxide, film-forming aid, and RM-8W thickener to the dispersion, stir and mix at a speed of 350 r / min for 14 min, add leveling agent, curing agent, aliphatic polyamide curing agent, stir and mix for 28 min, and pass through a 120 mesh sieve to obtain waterborne nano-graphene anti-corrosion coating.
[0098] The preparation method of the acrylic emulsion in this comparative example includes the following steps:
[0099] After thoroughly mixing deionized water and emulsifier, methyl methacrylate, butyl acrylate, styrene, hexafluorobutyl acrylate, dodecafluoroheptyl methacrylate, double-bonded polyethylene glycol methacrylate, and vinyltriethoxysilane are added and mixed thoroughly. The mixture is heated and stirred, and ammonium persulfate is added as an initiator. The mass ratio of deionized water, emulsifier, methyl methacrylate, butyl acrylate, styrene, hexafluorobutyl acrylate, dodecafluoroheptyl methacrylate, double-bonded polyethylene glycol methacrylate, vinyltriethoxysilane, and ammonium persulfate is 520:12:72:100:25:7:4:3:1.4:2.5. The reaction is carried out at 75°C for 4.5 hours. After the reaction is completed, the mixture is filtered and discharged to obtain an acrylic emulsion.
[0100] Comparative Example 3
[0101] A water-based nano-graphene anti-corrosion coating, the preparation method of which includes the following steps:
[0102] (1) Weigh the raw materials by weight, including 43 parts of waterborne epoxy resin, 28 parts of modified acrylic emulsion, 8 parts of curing agent aliphatic polyamide curing agent, 4.5 parts of film-forming aid, 1 part of RM-8W thickener, 0.25 parts of organosilicon defoamer BYK-024, 0.42 parts of dispersant SN-5040, 0.25 parts of leveling agent BYK-358N, and 22 parts of deionized water. The waterborne epoxy resin is composed of waterborne epoxy resin E51 and waterborne epoxy resin E44 in a mass ratio of 3:1, and the film-forming aid is composed of propylene glycol methyl ether acetate and dodecyl alcohol ester in a mass ratio of 2:1.
[0103] (2) Deionized water, dispersant SN-5040 and silicone defoamer BYK-024 were stirred at a speed of 700 r / min for 7 min to obtain a dispersion.
[0104] (3) Add waterborne epoxy resin, modified acrylic emulsion, film-forming aid, and RM-8W thickener to the dispersion, stir and mix at a speed of 350 r / min for 14 min, add leveling agent, curing agent, aliphatic polyamide curing agent, stir and mix for 28 min, and pass through a 120 mesh sieve to obtain waterborne nano-graphene anti-corrosion coating.
[0105] The preparation method of the modified acrylic emulsion in this comparative example includes the following steps:
[0106] S1. Graphene oxide and thionyl chloride in a mass ratio of 100:7000 are ultrasonically dispersed evenly, heated to 75°C and reacted for 15 hours. After the reaction is completed, the mixture is filtered, washed with petroleum ether, and dried to obtain acyl-chlorographene.
[0107] S2. Acyl-chlorographene was ultrasonically dispersed in dichloromethane. After uniform dispersion, 6-aminoisoquinoline and triethylamine were added, wherein the mass ratio of acyl-chlorographene, dichloromethane, 6-aminoisoquinoline and triethylamine was 100:2450:45:4. The mixture was stirred and reacted at 30°C for 9 hours. After the reaction was completed, the mixture was filtered, washed first with sodium bicarbonate, then washed with deionized water until neutral, and dried to obtain modified graphene.
[0108] S3. Modified graphene was ultrasonically dispersed in N,N-dimethylformamide, and 4-chloromethylstyrene was added, wherein the mass ratio of modified graphene, N,N-dimethylformamide, and 4-chloromethylstyrene was 100:1600:135. The mixture was stirred and heated to 80°C for 6 hours. After the reaction was completed, the mixture was filtered, washed with ethanol, and dried to obtain quaternary ammonium salt modified graphene.
[0109] S4. Mix deionized water and emulsifier evenly, then add methyl methacrylate, butyl acrylate, styrene, quaternary ammonium salt modified graphene, and vinyltriethoxysilane and mix evenly. Heat and stir, then add ammonium persulfate as an initiator. The mass ratio of deionized water, emulsifier, methyl methacrylate, butyl acrylate, styrene, quaternary ammonium salt modified graphene, vinyltriethoxysilane, and ammonium persulfate is 520:12:72:114:25:5:1.4:2.5. The reaction takes place at 75°C for 4.5 hours. After the reaction is complete, filter and discharge to obtain the modified acrylic emulsion.
[0110] In the embodiments and comparative examples of this invention, the graphene oxide is multilayer graphene oxide with a purity >95wt%, a thickness of 3.4-8nm, and a sheet diameter of 10-50μm, purchased from Suzhou Hengqiu Technology Co., Ltd.; the double-bonded polyethylene glycol methacrylate phosphate has the CAS number 35705-94-3; the emulsifier consists of sodium dodecyl sulfate and alkylphenol polyoxyethylene ether OP-10 in a mass ratio of 2:1; and the remaining reagents are commercially available.
[0111] The water-based nano-graphene anticorrosive coatings in Examples 4-7 and Comparative Examples 1-3 were subjected to relevant performance tests, the specific tests of which are as follows:
[0112] (1) Corrosion resistance test: According to GB / T 10125-2021 "Artificial atmosphere corrosion test - salt spray test", a 5% NaCl solution was used at a temperature of 35℃. The time when the first rust point appeared on the sample surface was observed, which is the salt spray resistance time.
[0113] (2) Adhesion test: According to GB / T 9286-2021 "Paints and Varnishes Cross-cut Test", the cross-cut test is adopted, and 10×10 grids (1 mm per grid) are made on the coating surface with a cross-cut knife. 2 After peeling off the tape, observe the extent of coating peeling within the grid and rate it from 0 to 5, where 0 means no peeling and 5 means complete peeling.
[0114] (3) Referring to GB / T 6739-2022 "Determination of Hardness of Paint Film by Pencil Method", use Zhonghua brand drawing pencil and push it on the paint film at an angle of about 45° to observe whether the paint film is scratched;
[0115] The test results are shown in Table 1:
[0116] Table 1
[0117]
[0118] As can be seen from the test results in Table 1, the water-based nano-graphene anticorrosive coatings corresponding to Examples 4-7 of this invention exhibit excellent corrosion resistance, good adhesion, and high hardness. In Comparative Example 1, γ-(methacryloyloxy)propyltrimethoxysilane was used to modify graphene oxide to obtain alkenyl graphene. Since no quinoline quaternary ammonium salt was introduced, the corrosion resistance was somewhat reduced. In Comparative Example 2, graphene oxide was directly added to the matrix, resulting in poor dispersion, significantly reduced barrier and mechanical properties, and a deterioration in overall performance. In Comparative Example 3, the modified acrylic emulsion replaced the functional monomers hexafluorobutyl acrylate, dodecafluoroheptyl methacrylate, and double-bonded polyethylene glycol methacrylate phosphate. Since no fluorinated monomers or phosphate functional monomers were introduced, the corrosion resistance of the coating was reduced.
[0119] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the present invention.
Claims
1. A water-based nano-graphene anti-corrosion coating, characterized in that: By weight, it comprises the following components: 32-45 parts waterborne epoxy resin, 21-30 parts modified acrylic emulsion, 5-9 parts curing agent, 3-5 parts film-forming aid, 0.5-1.2 parts thickener, 0.1-0.3 parts defoamer, 0.3-0.5 parts dispersant, 0.1-0.3 parts leveling agent, and 18-25 parts deionized water.
2. The water-based nano-graphene anti-corrosion coating according to claim 1, characterized in that: The waterborne epoxy resin is composed of waterborne epoxy resin E51 and waterborne epoxy resin E44 in a mass ratio of 3:
1.
3. The water-based nano-graphene anti-corrosion coating according to claim 1, characterized in that: The film-forming aid is composed of propylene glycol methyl ether acetate and dodecyl alcohol ester in a mass ratio of 2:
1.
4. The water-based nano-graphene anti-corrosion coating according to claim 1, characterized in that: The preparation method of the modified acrylic emulsion includes the following steps: S1. Graphene oxide is ultrasonically dispersed in thionyl chloride, heated, and reacted. After the reaction is complete, the mixture is filtered, washed, and dried to obtain acyl-chromium graphene. S2. Acyl-chlorographene was ultrasonically dispersed in dichloromethane. After uniform dispersion, 6-aminoisoquinoline and triethylamine were added, stirred and mixed, and the reaction was carried out. After the reaction was completed, the mixture was filtered, washed, and dried to obtain modified graphene. S3. The modified graphene was ultrasonically dispersed in N,N-dimethylformamide, 4-chloromethylstyrene was added, the mixture was stirred and heated to allow the reaction to proceed. After the reaction was completed, the graphene was filtered, washed, and dried to obtain quaternary ammonium salt modified graphene. S4. Mix deionized water and emulsifier evenly, then add methyl methacrylate, butyl acrylate, styrene, hexafluorobutyl acrylate, dodecafluoroheptyl methacrylate, double bond phosphate monomer, quaternary ammonium salt modified graphene, and vinyltriethoxysilane and mix evenly. Heat and stir, add initiator, and react. After the reaction is complete, filter and discharge to obtain modified acrylic emulsion.
5. The water-based nano-graphene anti-corrosion coating according to claim 4, characterized in that: In S1, the mass ratio of graphene oxide to sulfoxide is 100:6000-8000, the reaction temperature is 70-80℃, and the reaction time is 12-16h.
6. The water-based nano-graphene anti-corrosion coating according to claim 4, characterized in that: The mass ratio of acyl-chlorographene, dichloromethane, 6-aminoisoquinoline, and triethylamine in S2 is 100:2400-2500:38-55:3-5, the reaction temperature is 25-35℃, and the reaction time is 8-10h.
7. The water-based nano-graphene anti-corrosion coating according to claim 4, characterized in that: The mass ratio of modified graphene, N,N-dimethylformamide, and 4-chloromethylstyrene in S3 is 100:1500-1800:120-150, the reaction temperature is 75-85℃, and the reaction time is 5-8h.
8. The water-based nano-graphene anti-corrosion coating according to claim 4, characterized in that: In the S4 reaction, the mass ratio of deionized water, emulsifier, methyl methacrylate, butyl acrylate, styrene, hexafluorobutyl acrylate, dodecafluoroheptyl methacrylate, double bond phosphate monomer, quaternary ammonium salt modified graphene, vinyltriethoxysilane, and initiator is 480-550:8-15:65-80:100:20-30:5-8:3-5:2-4:4-7:1-2:2-3. The reaction temperature is 70-80℃, and the reaction time is 4-5 hours.
9. The water-based nano-graphene anti-corrosion coating according to claim 4, characterized in that: The initiator in S4 is ammonium persulfate.
10. A method for preparing an aqueous nano-graphene anti-corrosion coating as described in any one of claims 1-9, characterized in that: Includes the following steps: Step 1: Stir deionized water, dispersant, and defoamer at a speed of 600-800 r / min for 5-8 min to obtain a dispersion. Step 2: Add waterborne epoxy resin, modified acrylic emulsion, film-forming aid, and thickener to the dispersion, stir and mix at a speed of 300-400 r / min for 10-15 min, add leveling agent and curing agent, stir and mix for 20-30 min, and pass through a 120 mesh sieve to obtain waterborne nano-graphene anti-corrosion coating.