A water-based long-lasting protective graphene fluorocarbon topcoat

Abstract

The present invention relates to a water-based long-term protective graphene fluorocarbon topcoat, belonging to the technical field of coatings. The water-based long-term protective graphene fluorocarbon topcoat of the present invention is a two-component coating, including an acrylate emulsion and a polyurethane curing agent, wherein the acrylate emulsion includes the following components in parts by mass: 30 to 45 parts of water, 480 to 510 parts of fluorocarbon acrylate emulsion, 50 to 60 parts of rutile titanium dioxide, and 3 to 5 parts of nano-silicon dioxide; the preparation method of the fluorocarbon acrylate emulsion is as follows: polymerizing monomers, double-bond modified nanoparticles and emulsifiers in water under the action of an initiator to carry out emulsion polymerization. The present invention introduces graphene oxide, talcum powder and hollow glass microspheres into the fluorocarbon emulsion by chemical bonding, so that the coating has super weather resistance, excellent corrosion resistance, good wear resistance, high adhesion, good self-cleaning performance and good decorativeness.

Description

Technical Field

[0001] The invention relates to a water-based long-acting protective graphene fluorocarbon topcoat, belonging to the technical field of coatings. Background Art

[0002] With the development of society, people have put forward higher and higher requirements for the comprehensive performance of coatings, and the excellent decorative properties of coatings are increasingly valued by people. Due to its advantages such as good heat resistance, good oxidation resistance and low cost, acrylic emulsions are often used to prepare exterior wall architectural coatings. However, since acrylic emulsions themselves are easily affected by harsh external chemical environments, their polymer main chains are easily degraded under acidic or alkaline conditions, and their water resistance and salt spray resistance are far inferior to solvent-based resins, which restricts their application scope. In addition, the hydrophobicity, stain resistance and wear resistance of acrylic emulsions are also poor, resulting in their inability to be produced and applied on a large scale.

[0003] In order to solve the shortcomings of the above-mentioned acrylic emulsion, new low surface energy substances are usually introduced on the surface of the latex particles by chemical or other modification methods, such as using fluorinated monomers and other substances to improve the chemical solvent resistance, hydrophobicity, corrosion resistance and weather resistance of the emulsion. When the fluorinated monomer is used for polymerization, the CF bond will spontaneously migrate to the low surface energy interface. However, when the surrounding environment is water, the fluorinated group may migrate to the periphery of the latex particles, affecting the properties of the fluorinated polymer film. In fluorinated polymers, the main reason for the separation of fluorinated groups and non-fluorinated groups is due to different surface tensions. However, the mutual entanglement of polymer chains and the low swing energy often seriously hinder the migration of fluorinated groups to the surface, resulting in the inability to obtain the expected hydrophobicity. Therefore, the improvement of hydrophobicity and other properties of the surface treatment using low surface energy fluorocarbon compounds alone is limited. For this reason, people began to add inorganic nanoparticles to the emulsion to improve the hardness, scratch resistance, corrosion resistance and other properties of the resin matrix. However, the surface of inorganic nanoparticles is usually hydrophilic, which leads to poor dispersion in fluorocarbon acrylate emulsions, poor stability, and limited improvement in coating performance. Summary of the invention

[0004] The purpose of the present invention is to provide a water-based long-lasting protective graphene fluorocarbon topcoat to solve the problems of poor stability and limited performance improvement when inorganic particles are used to modify fluorocarbon acrylate emulsion.

[0005] The invention provides a water-based long-acting protective graphene fluorocarbon topcoat, which is a two-component coating, comprising an acrylate emulsion and a polyurethane curing agent, wherein the acrylate emulsion comprises the following components in parts by weight: 30-45 parts of water, 480-510 parts of fluorocarbon acrylate emulsion, 50-60 parts of rutile titanium dioxide, 3-5 parts of nano silicon dioxide, 4-6 parts of ethylene glycol, and 30-35 parts of propylene glycol methyl ether acetate; the preparation method of the fluorocarbon acrylate emulsion is as follows: a polymerization monomer, double-bond modified nanoparticles and an emulsifier are subjected to an emulsion polymerization reaction in water under the action of an initiator to obtain the fluorocarbon acrylate emulsion; the emulsifier The invention is composed of ammonium perfluorooctanoate and OP-10; the double-bond modified nanoparticles are composed of double-bond modified talc, double-bond modified hollow glass microspheres and double-bond modified graphene oxide in a mass ratio of (1.2-1.5):(0.5-0.8):2; the double-bond modified talc is prepared by a mixed reaction of a double-bond functionalized coupling agent and talc, the double-bond modified hollow glass microspheres are prepared by a mixed reaction of a double-bond functionalized coupling agent and hollow glass microspheres, the double-bond modified graphene oxide is prepared by a mixed reaction of a double-bond functionalized coupling agent and graphene oxide, and the double-bond functionalized coupling agent is prepared by a reaction of 3-aminopropyltrimethoxysilane and 10-undecenoyl chloride in a molar ratio of 1:1.

[0006] Preferably, the reaction temperature of the 3-aminopropyltrimethoxysilane and 10-undecenoyl chloride is 0-5° C. and the reaction time is 6-10 h.

[0007] Preferably, the preparation method of the double bond modified talc is as follows: a double bond functionalized coupling agent, ethanol and water are mixed to obtain a mixed solution, the pH of the mixed solution is adjusted to 3-4.5, and then an ethanol dispersion of talc is added, and the mixture is mixed and reacted at 60-80° C. for 6-8 hours to obtain a double bond modified talc; the mass ratio of the double bond functionalized coupling agent to the talc is (5-8):(2-3).

[0008] Preferably, the average particle size of the talc is 10-20 nm.

[0009] Preferably, the preparation method of the double bond modified hollow glass microspheres is as follows: a double bond functionalized coupling agent, ethanol and water are mixed to obtain a mixture, the pH of the mixture is adjusted to 3-4.5, and then an ethanol dispersion of hollow glass microspheres is added, and the mixture is mixed and reacted at 60-80° C. for 6-8 hours to obtain double bond modified hollow glass microspheres; the mass ratio of the double bond functionalized coupling agent to the hollow glass microspheres is (10-15):(3-5).

[0010] Preferably, the average particle size of the hollow glass microspheres is 10-20 μm, and the true density is 0.65-0.82 .

[0011] Preferably, the preparation method of the double bond modified graphene oxide is as follows: graphene oxide and water are evenly mixed to obtain a graphene oxide dispersion, and then an ethanol solution of a double bond functionalized coupling agent is added to the graphene oxide dispersion, and then the pH of the reaction system is adjusted to 4-5, mixed at room temperature for 30 minutes, and then heated to 50-70°C, mixed and reacted for 6-8 hours to obtain double bond modified graphene oxide; the mass ratio of the graphene oxide to the double bond functionalized coupling agent is 0.1:(0.8-1).

[0012] Preferably, the average sheet diameter of the graphene oxide is 100-200 nm.

[0013] Preferably, the mass of the double bond modified nanoparticles is 1-1.5% of the mass of the polymerized monomers.

[0014] Preferably, the initiator is a persulfate, and the mass of the initiator is 0.8-1.2% of the mass of the polymerized monomer; the temperature of the emulsion polymerization reaction is 80-85°C, and the time is 3-5h; the polymerized monomer is composed of 14-15 parts by mass of isooctyl methacrylate, 6-9 parts by mass of methyl methacrylate, 9-10 parts by mass of hydroxyethyl acrylate, 7-8 parts by mass of 2-(perfluorobutyl)ethyl acrylate, 3-4 parts by mass of 2-(perfluorooctyl)ethyl methacrylate and 1.5-2 parts by mass of 2-methyl-2-acrylic acid 2-(4-morpholinyl)ethyl ester; the mass of the emulsifier used for every 14-15g of isooctyl methacrylate is 1.2-1.5g, and the mass ratio of ammonium perfluorooctanoate to OP-10 is 1:2.

[0015] The beneficial effects of the present invention are as follows:

[0016] (1) The present invention uses a long carbon chain silane coupling agent to modify graphene oxide, talcum powder and hollow glass microspheres, and the modified graphene oxide, talcum powder and hollow glass microspheres participate in an emulsion polymerization reaction, which can improve the dispersion uniformity of graphene oxide, talcum powder and hollow glass microspheres in the emulsion and the bonding strength with the resin matrix, thereby improving the stability of the emulsion and the strength, corrosion resistance, weather resistance and wear resistance of the coating.

[0017] (2) The present invention uses talcum powder, graphene oxide and hollow glass microspheres with increasing particle sizes to effectively reduce the gaps between particles, improve the density of the coating, and effectively improve the corrosion resistance, weather resistance and wear resistance of the coating. At the same time, the compounding of solid particles of different particle sizes can form a wavy rough structure, further improving the hydrophobicity of the coating.

[0018] (3) The present invention uses a compound of solid particles of different densities, which can effectively avoid the problem of poor storage stability of the coating when a single solid particle is used. The use of graphene oxide and hollow glass microspheres with low density in combination with talcum powder with high density can increase the gravity of graphene oxide and hollow glass microspheres, increase the buoyancy of talcum powder, avoid floating or settling of particles, and improve the stability of the coating. In addition, during the film-forming process of the coating, the solid particles are more easily evenly dispersed in the coating under a uniform force state, thereby improving the strength, firmness, corrosion resistance, weather resistance and wear resistance of the coating.

[0019] (4) The present invention introduces graphene oxide, talcum powder and hollow glass microspheres into fluorocarbon emulsion by chemical bonding, so that the coating has super weather resistance, excellent corrosion resistance, good wear resistance, high adhesion, good self-cleaning performance and good decorative properties. Among them, the CF bond energy in fluorocarbon resin is high, and the proportion of photons in sunlight that can destroy the bond is small, which makes the fluorocarbon topcoat have excellent weather resistance, and graphene can transfer the photogenerated electrons generated by ultraviolet irradiation of pigments and fillers to prevent them from destroying the resin polymer chain, further extending the aging resistance of the coating. The topcoat of the present invention has an artificial accelerated aging resistance (UVB) of more than 6000 hours. Graphene has good chemical stability and barrier properties, can reduce gas and liquid permeability, and its flaky structure can form a physical barrier in the coating to prevent corrosive media from contacting the substrate. It can also synergize with fluorocarbon resins and the like to improve the anti-corrosion performance of the coating, and the protective life is expected to reach 30 to 50 years. The fluorocarbon topcoat of the present invention is strong in itself. After adding graphene, its flaky structure can enhance the toughness and hardness of the coating, making the coating less susceptible to damage such as wear and tear and shedding when subjected to mechanical effects such as friction and impact. It can effectively protect the surface of the coated object and extend its service life. It is suitable for occasions that require long-term wear protection, such as industrial equipment and floors. Graphene interacts with fluorocarbon resins and the like to improve the bonding force between the coating and the substrate, making the coating less likely to peel off and peel, and can form a firm attachment on the surface of a variety of substrates, ensuring long-term and effective protection and decorative effects. The fluorocarbon coating has low surface energy, dirt and microorganisms are not easy to adhere to, and the surface is smooth. Under natural conditions such as rain scouring, pollutants such as dust are easily washed away, keeping the surface clean and reducing maintenance costs. It is suitable for areas that are difficult to clean frequently, such as building exterior walls. The topcoat of the present invention can be stably compounded with a variety of commercially available water-based color pastes to form topcoat varieties with various colors and adjustable gloss, which can meet the decorative needs of different scenes and make the coated objects have good appearance effects. At the same time, it has excellent gloss and color retention properties, can maintain bright colors and good gloss for a long time, and improve the beauty and recognition of the objects.

[0020] (5) When the water-based long-term protective graphene fluorocarbon topcoat of the present invention is used in combination with the graphene zinc-based primer, that is, the anti-corrosion coating system of "primer (graphene zinc-based primer) + intermediate paint + topcoat (water-based long-term protective graphene fluorocarbon topcoat)" is used for the protection of bridge steel structures, the protection period is expected to reach 30 to 50 years, which can better meet the use requirements of the railway industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the storage stability test results of the water-based long-lasting protective graphene fluorocarbon topcoat of each embodiment of the present invention and the comparative example;

[0022] Figure 2 It is a schematic diagram of the test results of contact angle, self-cleaning performance, weather resistance and wear resistance of the water-based long-lasting protective graphene fluorocarbon topcoat of each embodiment of the present invention and the comparative example. DETAILED DESCRIPTION

[0023] The following examples are intended to further illustrate the present invention rather than to limit the scope of protection of the present invention.

[0024] Example 1

[0025] The water-based long-lasting protective graphene fluorocarbon topcoat of this embodiment is a two-component coating, including an acrylate emulsion and a polyurethane curing agent (the acrylate emulsion and the polyurethane curing agent are stored separately and mixed when used. The polyurethane curing agent is a water-based polyurethane curing agent, a commercial product, with the brand name Bayhydur XP2487 / 1 of Covestro, and the molar amount of hydroxyl groups in the acrylate emulsion and the molar amount of isocyanate groups in the water-based polyurethane curing agent are 1:1). The acrylate emulsion includes the following components in parts by mass: 40 parts of deionized water, 500 parts of fluorocarbon acrylate emulsion, 55 parts of rutile titanium dioxide, 4 parts of nano-silicon dioxide, 5 parts of ethylene glycol, and 33 parts of propylene glycol methyl ether acetate. Among them, the preparation method of the fluorocarbon acrylate emulsion is as follows:

[0026] (1) 3-aminopropyltrimethoxysilane and dichloromethane are added to a reactor and stirred evenly to obtain a 20% mass fraction 3-aminopropyltrimethoxysilane solution. The material temperature in the reactor is adjusted to 2°C, and then a 35% mass fraction 10-undecenoyl chloride dichloromethane solution (the molar ratio of 3-aminopropyltrimethoxysilane to 10-undecenoyl chloride is 1:1) is added dropwise to the reactor. After the addition is completed, triethylamine acid binding agent is added to the reactor, the reaction is stirred for 8 hours, and the solvent dichloromethane in the filtrate is filtered to remove the double bond functionalized coupling agent.

[0027] (2) Add 6 g of double bond functionalized coupling agent, 25 mL of anhydrous ethanol and 3 mL of deionized water into a flask, then add hydrochloric acid into the flask to adjust the pH of the material in the flask to 4, then add talc ethanol dispersion (prepared by dispersing 2 g of talc with an average particle size of 15 nm in 65 mL of ethanol) into the flask, then heat the material in the flask to 70 ° C, stir and reflux for 7 h, filter, and wash the filter cake with ethanol to obtain double bond modified talc.

[0028] (3) Add 12 g of double-bond functionalized coupling agent, 35 mL of anhydrous ethanol and 6 mL of deionized water into a flask, then add hydrochloric acid to the flask to adjust the pH of the material in the flask to 4, and then add ethanol dispersion of hollow glass microspheres (4 g of an average particle size of 15 μm and a true density of 0.75 The hollow glass microspheres are dispersed in 23 mL of ethanol), and then the materials in the flask are heated to 70°C, stirred and refluxed for 7 hours, filtered, and the filter cake is washed with ethanol to obtain double bond modified hollow glass microspheres.

[0029] (4) 0.1 g of graphene oxide (the average flake diameter of graphene oxide is 150 nm) and 30 mL of deionized water are stirred evenly to obtain a graphene oxide dispersion. An ethanol solution of a double bond functionalized coupling agent (prepared by stirring and mixing 0.9 g of a double bond functionalized coupling agent and 10 mL of ethanol) is added to the graphene oxide dispersion under stirring. The pH of the reaction system is then adjusted to 4.5 with hydrochloric acid. The mixture is stirred at room temperature for 30 min, then heated to 60 °C, stirred and refluxed for 7 h, filtered, and the filter cake is washed with ethanol to obtain double bond modified graphene oxide.

[0030] (5) Add the polymerized monomer, double bond modified nanoparticles (the mass of the double bond modified nanoparticles is 1.2% of the mass of the polymerized monomer, and the double bond modified nanoparticles are composed of double bond modified talc, double bond modified hollow glass microspheres and double bond modified graphene oxide in a mass ratio of 1.3:0.7:2) and 100 g of deionized water into a flask, start stirring, and then drop a 5% by mass potassium persulfate solution into the flask (the mass of potassium persulfate is 1% of the mass of the polymerized monomer). Then, heat the contents in the flask to 52°C, and then add 1.3 g of an emulsifier (the emulsifier is composed of ammonium perfluorooctanoate and OP-10 in a mass ratio of 1:2) into the flask, stir evenly, and then heat the contents in the flask to 82°C and stir for 4 h to obtain a fluorocarbon acrylate emulsion. Among them, the polymerization monomer consists of 14g of isooctyl methacrylate, 6 parts by mass of methyl methacrylate, 10 parts by mass of hydroxyethyl acrylate, 7g of 2-(perfluorobutyl)ethyl acrylate, 4g of 2-(perfluorooctyl)ethyl methacrylate and 2g of 2-methyl-2-acrylate 2-(4-morpholinyl)ethyl ester.

[0031] Example 2

[0032] The water-based long-lasting protective graphene fluorocarbon topcoat of this embodiment is a two-component coating, including an acrylate emulsion and a polyurethane curing agent (the acrylate emulsion and the polyurethane curing agent are stored separately and mixed when used. The polyurethane curing agent is a water-based polyurethane curing agent, a commercial product, with the brand name BayhydurXP2487 / 1 of Covestro, and the molar amount of hydroxyl groups in the acrylate emulsion and the molar amount of isocyanate groups in the water-based polyurethane curing agent are 1:1). The acrylate emulsion includes the following components in parts by mass: 30 parts of deionized water, 480 parts of fluorocarbon acrylate emulsion, 50 parts of rutile titanium dioxide, 3 parts of nano-silicon dioxide, 4 parts of ethylene glycol, and 30 parts of propylene glycol methyl ether acetate. Among them, the preparation method of the fluorocarbon acrylate emulsion is as follows:

[0033] (1) 3-aminopropyltrimethoxysilane and dichloromethane are added to a reactor and stirred evenly to obtain a 20% mass fraction 3-aminopropyltrimethoxysilane solution. The material temperature in the reactor is adjusted to 0°C, and then a 35% mass fraction 10-undecenoyl chloride dichloromethane solution (the molar ratio of 3-aminopropyltrimethoxysilane to 10-undecenoyl chloride is 1:1) is added dropwise to the reactor. After the addition is completed, triethylamine acid binding agent is added to the reactor, the reaction is stirred for 10 hours, and the filtrate is filtered to remove the solvent dichloromethane in the filtrate to obtain a double bond functionalized coupling agent.

[0034] (2) Add 5 g of double bond functionalized coupling agent, 20 mL of anhydrous ethanol and 2 mL of deionized water into a flask, then add hydrochloric acid into the flask to adjust the pH of the material in the flask to 3, then add talc ethanol dispersion (prepared by dispersing 2 g of talc with an average particle size of 10 nm in 60 mL of ethanol) into the flask, then heat the material in the flask to 60 ° C, stir and reflux for 6 h, filter, and wash the filter cake with ethanol to obtain double bond modified talc.

[0035] (3) Add 10 g of double-bond functionalized coupling agent, 30 mL of anhydrous ethanol and 4 mL of deionized water into a flask, then add hydrochloric acid to the flask to adjust the pH of the material in the flask to 3, and then add ethanol dispersion of hollow glass microspheres (3 g of an average particle size of 10 μm and a true density of 0.82) into the flask. The hollow glass microspheres are dispersed in 20 mL of ethanol), and then the materials in the flask are heated to 60°C, stirred and refluxed for 8 hours, filtered, and the filter cake is washed with ethanol to obtain double bond modified hollow glass microspheres.

[0036] (4) 0.1 g of graphene oxide (the average flake diameter of graphene oxide is 200 nm) and 30 mL of deionized water are stirred evenly to obtain a graphene oxide dispersion. An ethanol solution of a double bond functionalized coupling agent (prepared by stirring and mixing 0.8 g of a double bond functionalized coupling agent and 10 mL of ethanol) is added to the graphene oxide dispersion under stirring. The pH of the reaction system is then adjusted to 4 with hydrochloric acid. The mixture is stirred at room temperature for 30 min, then heated to 50 °C, stirred and refluxed for 8 h, filtered, and the filter cake is washed with ethanol to obtain double bond modified graphene oxide.

[0037] (5) Add the polymerized monomer, double bond modified nanoparticles (the mass of the double bond modified nanoparticles is 1% of the mass of the polymerized monomer, and the double bond modified nanoparticles are composed of double bond modified talc, double bond modified hollow glass microspheres and double bond modified graphene oxide in a mass ratio of 1.2:0.8:2) and 100 g of deionized water into a flask, start stirring, and then drop a 5% by mass potassium persulfate solution into the flask (the mass of potassium persulfate is 0.8% of the mass of the polymerized monomer). Then, heat the contents in the flask to 50°C, and then add 1.2 g of an emulsifier (the emulsifier is composed of ammonium perfluorooctanoate and OP-10 in a mass ratio of 1:2) into the flask, stir evenly, and then heat the contents in the flask to 80°C and stir for 5 hours to obtain a fluorocarbon acrylate emulsion. Among them, the polymerization monomer consists of 14g of isooctyl methacrylate, 9 parts by mass of methyl methacrylate, 9 parts by mass of hydroxyethyl acrylate, 7g of 2-(perfluorobutyl)ethyl acrylate, 3g of 2-(perfluorooctyl)ethyl methacrylate and 1.5g of 2-methyl-2-acrylate 2-(4-morpholinyl)ethyl ester.

[0038] Example 3

[0039] The water-based long-lasting protective graphene fluorocarbon topcoat of this embodiment is a two-component coating, including an acrylate emulsion and a polyurethane curing agent (the acrylate emulsion and the polyurethane curing agent are stored separately and mixed when used. The polyurethane curing agent is a water-based polyurethane curing agent, a commercially available product with the brand name Bayhydur XP2487 / 1 from Covestro. The molar amount of hydroxyl groups in the acrylate emulsion and the molar amount of isocyanate groups in the water-based polyurethane curing agent are 1:1). The acrylate emulsion includes the following components in parts by mass: 45 parts of deionized water, 510 parts of fluorocarbon acrylate emulsion, 60 parts of rutile titanium dioxide, 5 parts of nano-silicon dioxide, 6 parts of ethylene glycol, and 35 parts of propylene glycol methyl ether acetate. Among them, the preparation method of the fluorocarbon acrylate emulsion is as follows:

[0040] (1) Add 3-aminopropyltrimethoxysilane and dichloromethane into a reactor and stir evenly to obtain a 20% mass fraction 3-aminopropyltrimethoxysilane solution. Adjust the material temperature in the reactor to 5°C, and then dropwise add a 35% mass fraction 10-undecenoyl chloride dichloromethane solution into the reactor (the molar ratio of 3-aminopropyltrimethoxysilane to 10-undecenoyl chloride is 1:1). After the dropwise addition is completed, add triethylamine acid binding agent into the reactor, stir the reaction for 6 hours, filter, remove the solvent dichloromethane in the filtrate, and obtain a double bond functionalized coupling agent.

[0041] (2) 8 g of double bond functionalized coupling agent, 30 mL of anhydrous ethanol and 5 mL of deionized water were added to a flask, and hydrochloric acid was added to the flask to adjust the pH of the material in the flask to 4.5. Then, an ethanol dispersion of talc (prepared by dispersing 3 g of talc with an average particle size of 20 nm in 70 mL of ethanol) was added to the flask. The material in the flask was then heated to 80°C, stirred and refluxed for 8 h, filtered, and the filter cake was washed with ethanol to obtain double bond modified talc.

[0042] (3) Add 15 g of double-bond functionalized coupling agent, 40 mL of anhydrous ethanol and 8 mL of deionized water into a flask, then add hydrochloric acid into the flask to adjust the pH of the material in the flask to 4.5, and then add ethanol dispersion of hollow glass microspheres (5 g of an average particle size of 20 μm and a true density of 0.65 The hollow glass microspheres are dispersed in 25 mL of ethanol), and then the materials in the flask are heated to 80°C, stirred and refluxed for 6 hours, filtered, and the filter cake is washed with ethanol to obtain double bond modified hollow glass microspheres.

[0043] (4) 0.1 g of graphene oxide (the average sheet diameter of graphene oxide is 100 nm) and 30 mL of deionized water are stirred evenly to obtain a graphene oxide dispersion. An ethanol solution of a double bond functionalized coupling agent (prepared by stirring and mixing 1 g of a double bond functionalized coupling agent and 10 mL of ethanol) is added to the graphene oxide dispersion under stirring. The pH of the reaction system is then adjusted to 5 with hydrochloric acid. The mixture is stirred at room temperature for 30 min, then heated to 70 °C, stirred and refluxed for 6 h, filtered, and the filter cake is washed with ethanol to obtain double bond modified graphene oxide.

[0044] (5) Add the polymerized monomer, double bond modified nanoparticles (the mass of the double bond modified nanoparticles is 1.5% of the mass of the polymerized monomer, and the double bond modified nanoparticles are composed of double bond modified talc, double bond modified hollow glass microspheres and double bond modified graphene oxide in a mass ratio of 1.5:0.5:2) and 100 g of deionized water into a flask, start stirring, and then drop a 5% by mass potassium persulfate solution into the flask (the mass of potassium persulfate is 1.2% of the mass of the polymerized monomer). Then, heat the contents in the flask to 55°C, and then add 1.5 g of an emulsifier (the emulsifier is composed of ammonium perfluorooctanoate and OP-10 in a mass ratio of 1:2) into the flask, stir evenly, and then heat the contents in the flask to 85°C and stir for 3 h to obtain a fluorocarbon acrylate emulsion. Among them, the polymerization monomer consists of 15g of isooctyl methacrylate, 7 parts by mass of methyl methacrylate, 9 parts by mass of hydroxyethyl acrylate, 8g of 2-(perfluorobutyl)ethyl acrylate, 4g of 2-(perfluorooctyl)ethyl methacrylate and 2g of 2-methyl-2-acrylate 2-(4-morpholinyl)ethyl ester.

[0045] Comparative Example 1

[0046] The difference between the water-based long-lasting protective graphene fluorocarbon topcoat of this comparative example and the water-based long-lasting protective graphene fluorocarbon topcoat of Example 1 is that in step (5) of the method for preparing the fluorocarbon acrylate emulsion used in the water-based long-lasting protective graphene fluorocarbon topcoat of this comparative example, the double bond-modified nanoparticles are replaced by nanoparticles, and the nanoparticles are composed of talcum powder, hollow glass microspheres and graphene oxide in a mass ratio of 1.3:0.7:2, the talcum powder is the talcum powder in step (2) of preparing the fluorocarbon acrylate emulsion in Example 1, the hollow glass microspheres are the hollow glass microspheres in step (3) of preparing the fluorocarbon acrylate emulsion in Example 1, and the graphene oxide is the graphene oxide in step (4) of preparing the fluorocarbon acrylate emulsion in Example 1.

[0047] Comparative Example 2

[0048] The difference between the water-based long-lasting protective graphene fluorocarbon topcoat of this comparative example and the water-based long-lasting protective graphene fluorocarbon topcoat of Example 1 is that in step (5) of the preparation method of the fluorocarbon acrylate emulsion used in the water-based long-lasting protective graphene fluorocarbon topcoat of this comparative example, ammonium perfluorooctanoate is replaced by sodium dodecyl sulfate.

[0049] Comparative Example 3

[0050] The only difference between the water-based long-lasting protective graphene fluorocarbon topcoat of this comparative example and the water-based long-lasting protective graphene fluorocarbon topcoat of Example 1 is that the double-bond modified nanoparticles used in step (5) of the preparation method of the fluorocarbon acrylate emulsion used in the water-based long-lasting protective graphene fluorocarbon topcoat of this comparative example are composed of double-bond modified talc and double-bond modified hollow glass microspheres in a mass ratio of 1.3:0.7.

[0051] Comparative Example 4

[0052] The only difference between the water-based long-lasting protective graphene fluorocarbon topcoat of this comparative example and the water-based long-lasting protective graphene fluorocarbon topcoat of Example 1 is that the double-bond modified nanoparticles used in step (5) of the preparation method of the fluorocarbon acrylate emulsion used in the water-based long-lasting protective graphene fluorocarbon topcoat of this comparative example are composed of double-bond modified hollow glass microspheres and double-bond modified graphene oxide in a mass ratio of 0.7:2.

[0053] Comparative Example 5

[0054] The only difference between the water-based long-lasting protective graphene fluorocarbon topcoat of this comparative example and the water-based long-lasting protective graphene fluorocarbon topcoat of Example 1 is that the double-bond modified nanoparticles used in step (5) of the preparation method of the fluorocarbon acrylate emulsion used in the water-based long-lasting protective graphene fluorocarbon topcoat of this comparative example are composed of double-bond modified talc and double-bond modified graphene oxide in a mass ratio of 1.3:2.

[0055] Comparative Example 6

[0056] The only difference between the water-based long-lasting protective graphene fluorocarbon topcoat of this comparative example and the water-based long-lasting protective graphene fluorocarbon topcoat of Example 1 is that the double-bond modified nanoparticles used in step (5) of the preparation method of the fluorocarbon acrylate emulsion used in the water-based long-lasting protective graphene fluorocarbon topcoat of this comparative example are double-bond modified talc.

[0057] Comparative Example 7

[0058] The only difference between the water-based long-lasting protective graphene fluorocarbon topcoat of this comparative example and the water-based long-lasting protective graphene fluorocarbon topcoat of Example 1 is that the double-bond modified nanoparticles used in step (5) of the preparation method of the fluorocarbon acrylate emulsion used in the water-based long-lasting protective graphene fluorocarbon topcoat of this comparative example are double-bond modified hollow glass microspheres.

[0059] Comparative Example 8

[0060] The only difference between the water-based long-lasting protective graphene fluorocarbon topcoat of this comparative example and the water-based long-lasting protective graphene fluorocarbon topcoat of Example 1 is that the double-bond modified nanoparticles used in step (5) of the preparation method of the fluorocarbon acrylate emulsion used in the water-based long-lasting protective graphene fluorocarbon topcoat of this comparative example are double-bond modified graphene oxide.

[0061] Comparative Example 9

[0062] The only difference between the water-based long-lasting protective graphene fluorocarbon topcoat of this comparative example and the water-based long-lasting protective graphene fluorocarbon topcoat of Example 1 is that in step (5) of the method for preparing the fluorocarbon acrylate emulsion used in the water-based long-lasting protective graphene fluorocarbon topcoat of this comparative example, the polymerization monomers are composed of isooctyl methacrylate, methyl methacrylate, 2-(perfluorobutyl) ethyl acrylate and 2-(perfluorooctyl) ethyl methacrylate, and the total mass of isooctyl methacrylate, methyl methacrylate, 2-(perfluorobutyl) ethyl acrylate and 2-(perfluorooctyl) ethyl methacrylate is 45 g, and the mass ratio is 14:18:7:4.

[0063] Comparative Example 10

[0064] The difference between the water-based long-lasting protective graphene fluorocarbon topcoat of this comparative example and the water-based long-lasting protective graphene fluorocarbon topcoat of Example 1 is that in step (1) of the preparation method of the fluorocarbon acrylate emulsion used in the water-based long-lasting protective graphene fluorocarbon topcoat of this comparative example, 10-undecenoyl chloride is replaced by acryloyl chloride.

[0065] Experimental Example 1

[0066] In order to evaluate the actual application effect of the water-based long-lasting protective graphene fluorocarbon topcoat of each embodiment and comparative example, the storage stability, adhesion to different substrates, contact angle, self-cleaning performance, corrosion resistance, weather resistance and wear resistance of the water-based long-lasting protective graphene fluorocarbon topcoat of each embodiment and comparative example were tested respectively.

[0067] The storage stability test method is as follows: the storage stability is tested according to the method in the standard GB / T6753.3-1986 "Test method for storage stability of coatings", the sample is placed in a blast drying oven with a set temperature of (50±2)℃, and the time when solid sedimentation or stratification occurs in the topcoat is recorded. The results are shown in Table 1 and Figure 1 shown.

[0068] The adhesion test method is as follows: the coating is applied to the substrate with a 100 μm wire rod applicator, baked at 80°C for 30 minutes, and placed at room temperature for 5 days. The coating is then tested and rated according to the method specified in the standard GBT9286-1998 "Scratch test for paint and varnish films". The substrates are poplar board, cement board, glass, ABS plastic, and iron plate. The results are shown in Table 1.

[0069] The contact angle test method is as follows: the coating is applied on a glass plate with a 100 μm wire rod applicator, baked at 80 ° C for 30 min, dried at room temperature for 24 h, and then the contact angle between the coating and water is measured using a contact angle tester Dataphysics OCA35. The water drop volume is 4 μL. Five contact angles are measured for each coating, and then the average value is calculated. The results are shown in Table 2 and Figure 2 shown.

[0070] The test method of self-cleaning performance is as follows: the coating is applied on a glass plate with a 100 μm wire rod coater, baked at 80°C for 30 min, and placed at room temperature for 5 days. The coating is divided into two parts of equal area, namely part A and part B. A layer with a density of 0.1 The glass plate was tilted at an angle of 10 degrees, and then sprayed vertically downward from 20 cm above the top. The A and B parts of the coating were sprayed in the same way to simulate the erosion of rainwater in nature. The glass plate was then placed horizontally in a drying oven for drying. After drying, the reflectance coefficients of the A and B parts of the coating were tested, which were Fa and Fb, respectively. The reflectance coefficient change rate was calculated using the formula (Fb-Fa) / Fb. The self-cleaning performance was evaluated using the reflectance coefficient change rate. The results are shown in Tables 2 and 3. Figure 2 shown.

[0071] The corrosion resistance test method is as follows: the coating is applied to the steel plate with a 100μm wire rod applicator, baked at 80℃ for 30min, and placed at room temperature for 5d. A cross line is drawn on the coating film with a cutter until the steel plate is exposed. The scratch is greater than 20mm from any edge of the steel plate, and the edges are sealed with wax. Then, a neutral salt spray resistance test is performed according to the method in standard GB10125-1997. During the test, the time t1 when rust spots appear on the plate surface and the time t2 when the corrosion at the scratch line reaches 2cm wide are observed and recorded. The minimum value between time t1 and time t2 is taken as the salt spray corrosion resistance time of the coating. The results are shown in Table 2.

[0072] The test method for weather resistance is as follows: the coating is applied on a glass plate with a 100μm wire rod applicator, baked at 80℃ for 30min, dried at room temperature for 24h, and then tested for weather resistance according to the method in standard GB / T1865-1997 "Artificial weathering and artificial radiation exposure (filtered xenon arc radiation) of paints and varnishes". During the experiment, the absolute value of the color difference between the coating before the test and the test time of 6000h was detected and recorded. The results are shown in Table 2 and Figure 2 shown.

[0073] The test method for wear resistance is as follows: the coating is applied on a glass plate with a 100 μm wire rod applicator, baked at 80°C for 30 min, placed at room temperature for 5 days, and then subjected to abrasion test using an abrasion tester. A rubber grinding wheel is used during the test, and the load weight is 1000 g. At the end of the test, the weight loss of the coating during the abrasion test is calculated in mg. The results are shown in Table 2 and Figure 2 shown.

[0074] Table 1 Storage stability of water-based long-term protective graphene fluorocarbon topcoat of each embodiment and comparative example and adhesion to different substrates

[0075]

[0076] Table 2 Contact angle, self-cleaning performance, corrosion resistance, weather resistance and wear resistance of water-based long-term protective graphene fluorocarbon topcoat of each embodiment and comparative example

[0077]

[0078] As shown in Table 1 and Table 2, the present invention can make the coating have super strong weather resistance, excellent corrosion resistance, good wear resistance, high adhesion and good self-cleaning performance by introducing graphene oxide, talcum powder and hollow glass microspheres into fluorocarbon emulsion by chemical bonding. Compared with Comparative Examples 1 and 10, the graphene oxide, talcum powder and hollow glass microspheres are modified by long carbon chain silane coupling agent, and the modified graphene oxide, talcum powder and hollow glass microspheres are involved in emulsion polymerization, which can improve the dispersion uniformity of graphene oxide, talcum powder and hollow glass microspheres in the emulsion and the bonding strength with the resin matrix, improve the stability of the emulsion and the strength, corrosion resistance, weather resistance and wear resistance of the coating. Compared with Comparative Examples 3-8, the use of modified graphene oxide, talcum powder and hollow glass microspheres in combination can effectively play the synergistic effect between solid particles, and further improve the corrosion resistance, weather resistance and wear resistance of the coating. Compared with Comparative Example 2, the use of an emulsifier containing fluorine atoms can effectively improve the compatibility between the fluorine-containing polymerizable monomer and other monomers and the modified solid particles, thereby improving the bonding strength between the components during emulsion polymerization and improving the coating performance. Compared with Comparative Example 9, the use of 2-methyl-2-acrylic acid 2-(4-morpholinyl)ethyl ester, the morpholinyl group in the monomer can effectively wrap the solid particles, improve the uniformity of the solid particles in the latex particles, and thus improve the comprehensive performance of the coating.

[0079] Experimental Example 2

[0080] In order to investigate the effect of graphene on the performance of coatings and the aging resistance of graphene-free and graphene-containing topcoats, artificial accelerated aging tests were carried out on fluorocarbon topcoat coatings with and without graphene. The test methods and test conditions were carried out in accordance with standard Q / CR749.1-2020. The sample topcoat coating was designed to be 70μm. The test results were compared and analyzed around the color difference and gloss retention rate of the coating sample. The test results show that when the fluorocarbon topcoat without graphene was tested for 5000 h in artificial accelerated aging, the gloss retention rate of the paint film was above 90%; when the test was 6000 h, the gloss retention rate of the paint film was less than 80%. When the fluorocarbon topcoat containing graphene was tested for 6500 h in artificial accelerated aging, the gloss retention rate of the paint film remained above 90%, which was significantly better than the fluorocarbon topcoat without graphene; the color difference was significantly smaller than that of the fluorocarbon topcoat without graphene and was more stable with the test time. All technical indicators of graphene fluorocarbon topcoat meet or exceed the standard requirements. The 70μm coating has been resistant to 6800h of artificial accelerated aging test. The sample coating film has no obvious discoloration, no powdering, no cracking, no blistering, no rust, and no peeling. The coating gloss retention rate is more than 90%, which is significantly better than the technical requirement of 3000h of artificial accelerated aging test of the railway industry standard. The graphene fluorocarbon topcoat coating has excellent aging resistance.

[0081] In addition, in existing bridge projects at home and abroad, under different atmospheric corrosion environments, the anti-corrosion coating system of "primer (graphene zinc-based primer) + intermediate paint + topcoat (water-based long-term protective graphene fluorocarbon topcoat)" was used for the construction of bridge steel structures. The anti-corrosion coating system was based on the 7th set of railway standard Q / CR749.1-2020 anti-corrosion coating system and combined with the technical index requirements of the typical anti-corrosion coating system with a design protection period of 15 to 25 years in ISO12944 and JT / T722. It was compared with the typical anti-corrosion coating system with a protection period of 15 to 25 years used in existing engineering examples. The results showed that the durability of the anti-corrosion coating system of "primer (graphene zinc-based primer) + intermediate paint + topcoat (water-based long-term protective graphene fluorocarbon topcoat)" is far superior to the typical anti-corrosion coating system. Among them, the salt spray resistance of graphene zinc primer coating is 4.5 times that of typical anti-corrosion coating system, and the aging resistance of graphene fluorocarbon topcoat coating is 2.26 times that of typical anti-corrosion coating system, and the system has excellent anti-corrosion performance. Therefore, the anti-corrosion coating system of "primer (graphene zinc-based primer) + intermediate paint + topcoat (water-based long-term protective graphene fluorocarbon topcoat)" can provide longer protection for bridge steel structures.

[0082] When using the graphene zinc-based fluorocarbon ultra-durable anti-corrosion coating system for different atmospheric corrosion environments, it is necessary to further carry out detailed designs such as paint film thickness, coating structure and construction process, so that the protection period of the coating system meets the design requirements. Combined with the above analysis, the design protection period of the new graphene zinc-based fluorocarbon ultra-durable anti-corrosion coating system can reach at least twice the protection period of the typical steel bridge anti-corrosion coating system, which can reach 30 to 50 years. When the raw materials and construction quality control are better, the protection period is longer.

Claims

1. A water-based long-lasting protective graphene fluorocarbon topcoat, characterized in that: The water-based long-term protective graphene fluorocarbon topcoat is a two-component coating, including an acrylate emulsion and a polyurethane curing agent, wherein the acrylate emulsion includes the following components in parts by weight: 30-45 parts of water, 480-510 parts of fluorocarbon acrylate emulsion, 50-60 parts of rutile titanium dioxide, 3-5 parts of nano silicon dioxide, 4-6 parts of ethylene glycol, and 30-35 parts of propylene glycol methyl ether acetate; the preparation method of the fluorocarbon acrylate emulsion is as follows: polymerizing monomers, double-bond modified nanoparticles and emulsifiers are subjected to emulsion polymerization in water under the action of an initiator to obtain a fluorocarbon acrylate emulsion; the emulsifier is composed of ammonium perfluorooctanoate and OP-10; the double-bond modified nanoparticles are composed of a mass ratio of (1.2-1.5 ):(0.5~0.8):2 double bond modified talc, double bond modified hollow glass microspheres and double bond modified graphene oxide; the double bond modified talc is prepared by a mixed reaction of a double bond functionalized coupling agent and talc, the double bond modified hollow glass microspheres are prepared by a mixed reaction of a double bond functionalized coupling agent and hollow glass microspheres, the double bond modified graphene oxide is prepared by a mixed reaction of a double bond functionalized coupling agent and graphene oxide, and the double bond functionalized coupling agent is prepared by a reaction of 3-aminopropyltrimethoxysilane and 10-undecenoyl chloride in a molar ratio of 1:1; the average particle size of the talc is 10~20nm, the average particle size of the hollow glass microspheres is 10~20μm, and the true density is 0.65~0.82 The average sheet diameter of the graphene oxide is 100-200 nm; the polymerization monomer consists of 14-15 parts by mass of isooctyl methacrylate, 6-9 parts by mass of methyl methacrylate, 9-10 parts by mass of hydroxyethyl acrylate, 7-8 parts by mass of 2-(perfluorobutyl)ethyl acrylate, 3-4 parts by mass of 2-(perfluorooctyl)ethyl methacrylate and 1.5-2 parts by mass of 2-methyl-2-acrylic acid 2-(4-morpholinyl)ethyl ester.

2. The water-based long-lasting protective graphene fluorocarbon topcoat according to claim 1, characterized in that: The reaction temperature of the 3-aminopropyltrimethoxysilane and 10-undecenoyl chloride is 0-5° C. and the reaction time is 6-10 hours.

3. The water-based long-lasting protective graphene fluorocarbon topcoat according to claim 1, characterized in that: The preparation method of the double-bond modified talc is as follows: a double-bond functionalized coupling agent, ethanol and water are mixed to obtain a mixed solution, the pH of the mixed solution is adjusted to 3-4.5, and then an ethanol dispersion of talc is added, and the mixture is mixed and reacted at 60-80° C. for 6-8 hours to obtain the double-bond modified talc; The mass ratio of the double bond functionalized coupling agent to talc is (5-8):(2-3).

4. The water-based long-lasting protective graphene fluorocarbon topcoat according to claim 1, characterized in that: The preparation method of the double-bond modified hollow glass microspheres is as follows: a double-bond functionalized coupling agent, ethanol and water are mixed to obtain a mixture, the pH of the mixture is adjusted to 3-4.5, and then an ethanol dispersion of hollow glass microspheres is added, and mixed and reacted at 60-80° C. for 6-8 hours to obtain double-bond modified hollow glass microspheres; the mass ratio of the double-bond functionalized coupling agent to the hollow glass microspheres is (10-15):(3-5).

5. The water-based long-lasting protective graphene fluorocarbon topcoat according to claim 1, characterized in that: The preparation method of the double-bond modified graphene oxide is as follows: graphene oxide and water are mixed evenly to obtain a graphene oxide dispersion, an ethanol solution of a double-bond functionalized coupling agent is added to the graphene oxide dispersion, the pH of the reaction system is adjusted to 4-5, the mixture is mixed at room temperature for 30 minutes, the mixture is heated to 50-70° C., and the mixture is mixed for 6-8 hours to obtain double-bond modified graphene oxide; the mass ratio of the graphene oxide to the double-bond functionalized coupling agent is 0.1:(0.8-1).

6. The water-based long-lasting protective graphene fluorocarbon topcoat according to claim 1, characterized in that: The mass of the double bond modified nanoparticles is 1-1.5% of the mass of the polymerized monomers.

7. The water-based long-lasting protective graphene fluorocarbon topcoat according to claim 1, characterized in that: The initiator is persulfate, and the mass of the initiator is 0.8-1.2% of the mass of the polymerization monomer; the temperature of the emulsion polymerization reaction is 80-85°C, and the time is 3-5 hours; the mass of the emulsifier used for every 14-15g of isooctyl methacrylate is 1.2-1.5g, and the mass ratio of ammonium perfluorooctanoate to OP-10 is 1:2.

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