Self-cleaning fluorocarbon finish and method of making same

Abstract

The present application relates to fluorocarbon finish technology field, specifically to a kind of self-cleaning fluorocarbon finish and preparation method thereof, including the following weight parts raw materials: fluorocarbon resin 40-50 parts, hydroxyl acrylic resin 5-10 parts, nano kaolin reinforcing agent 6-10 parts, modified nano silica agent 4-8 parts, defoaming agent 0.3-0.6 parts, leveling agent 0.4-0.8 parts, dispersing agent 0.5-1.0 parts, curing agent 8-12 parts, solvent 15-25 parts.The present application is with fluorocarbon resin, hydroxyl acrylic resin as matrix, by adding nano kaolin reinforcing agent, modified nano silica agent coordination cooperation enhancement, the functional additives such as defoaming agent, leveling agent, dispersing agent are added and are harmonized, through the co-configuration of raw materials, mutual synergism, the high self-cleaning of product, strong adhesion, excellent mechanical properties, high weather resistance and corrosion resistance and stability effect are remarkable, and the comprehensive coordination of product is excellent.

Description

Technical Field

[0001] This invention relates to the field of fluorocarbon topcoat technology, specifically to a self-cleaning fluorocarbon topcoat and its preparation method. Background Technology

[0002] Fluorocarbon topcoats, with their high bond energy and chemical inertness of the CF bond, are widely used in building exteriors, steel structures, marine engineering, and rail transportation, combining excellent weather resistance, corrosion resistance, and decorative properties. As the demand for long-term outdoor protection increases, self-cleaning performance has become a core indicator for high-end fluorocarbon topcoats. Currently, most self-cleaning fluorocarbon topcoats achieve this by adding nano-silica and nano-TiO₂. Fluorosurfactants and other agents enhance hydrophobicity and self-cleaning properties, but they generally suffer from the following drawbacks: self-cleaning modifiers easily disrupt the interfacial bonding of the coating, significantly reducing adhesion and leading to peeling and flaking; uneven dispersion of nanofillers results in a decrease in mechanical properties such as hardness, abrasion resistance, and impact strength; under complex environments such as acid and alkali, salt spray, humid heat, and strong ultraviolet radiation, the coating is prone to chalking, cracking, discoloration, and corrosion penetration, exhibiting poor weather resistance and corrosion stability; and the overall coordination of self-cleaning, adhesion, mechanical, weather resistance, and corrosion resistance is poor, making it difficult to meet the requirements for long-term outdoor use. Therefore, developing a self-cleaning fluorocarbon topcoat that balances high self-cleaning properties, strong adhesion, excellent mechanical properties, high weather resistance and corrosion stability, and achieves a synergistic balance of overall performance has become an urgent technical problem to be solved in this field. Summary of the Invention

[0003] In view of the deficiencies of the prior art, the purpose of this invention is to provide a self-cleaning fluorocarbon topcoat and its preparation method, so as to solve the problems mentioned in the background art.

[0004] The present invention solves the technical problem by adopting the following technical solution:

[0005] This invention provides a self-cleaning fluorocarbon topcoat, the raw materials of which, by weight, include: 40-50 parts of fluorocarbon resin, 5-10 parts of hydroxyl acrylic resin, 6-10 parts of nano-kaolin reinforcing agent, 4-8 parts of modified nano-silica agent, 0.3-0.6 parts of defoamer, 0.4-0.8 parts of leveling agent, 0.5-1.0 parts of dispersant, 8-12 parts of curing agent, and 15-25 parts of solvent.

[0006] Preferably, the fluorocarbon resin is FEVE fluorocarbon resin with a fluorine content ≥24%; the curing agent is HDI trimer curing agent; the hydroxyl acrylic resin has a viscosity of 2500-6000 cps, a solid content of 70%, a hydroxyl value of 80-100 mgKOH / g, an acid value <8 mgKOH / g, and a number-average molecular weight Mn of 8000-12000;

[0007] The solvent is a mixture of butyl acetate, xylene, and propylene glycol methyl ether acetate in a weight ratio of 3:2:1; the defoamer is polydimethylsiloxane, the leveling agent is acrylate leveling agent, and the dispersant is ammonium polyacrylate dispersant.

[0008] Preferably, the preparation method of the nano-kaolin reinforcing agent includes the following steps:

[0009] S01: Preheat the nano-kaolin at 55-60℃ for 1 hour to obtain preheated nano-kaolin; subject the preheated nano-kaolin and reinforcing liquid to ultrasonic reinforcement at a weight ratio of 3:(4-7) to obtain reinforced nano-kaolin liquid.

[0010] The preparation method of the enhancement liquid is as follows:

[0011] S01a: Add 2-4 parts of a 2-5% (w / w) lanthanum chloride solution and 1-3 parts of nano-α-Al O Mix 3-5 parts of pyrophyllite powder and 2-4 parts of sodium citrate solution with a mass fraction of 8-12% evenly to obtain an impregnation solution; immerse basalt fibers in an impregnation solution with a volume of 3-5 times the total volume of the basalt fiber and stir thoroughly to obtain a basalt fiber solution.

[0012] S01b: Mix 2-4 parts sepiolite powder, 1-3 parts potassium feldspar powder and 2-4 parts nano zinc oxide evenly to obtain an additive; mix the additive and basalt fiber liquid in a weight ratio of 3:(5-7) and stir thoroughly to obtain a reinforcing liquid;

[0013] S02: Mix 2-4 parts of quartz, 1-3 parts of calcium sulfate whiskers and 2-4 parts of calcined talc powder evenly to obtain an additive; mix the enhanced nano-kaolin liquid and the additive at a weight ratio of (8-11):5, and ball mill them at a speed of 1000-1500 r / min for 2 hours. After ball milling, filter and dry to obtain the nano-kaolin reinforcing agent.

[0014] Preferably, the nano-kaolin has a particle size of 30-80 nm and a specific surface area of ​​80-120 m². / g; Nano α-Al O The particle size is 20-50 nm; the diameter of basalt fibers is 5-10 μm and the length is 50-100 μm; the diameter of calcium sulfate whiskers is 1-3 μm and the aspect ratio is 20-40.

[0015] Preferably, the ultrasonic power of the ultrasonic enhancement treatment is 350-400W, and the ultrasonic time is 1 hour.

[0016] Preferably, the preparation method of the modified nano-silica agent includes the following steps:

[0017] S11: Mix β-cyclodextrin, sodium silicate solution, 75-85% ethanol solution and silane coupling agent KH550 in a weight ratio of (3-5):2:(8-11):1 to obtain β-cyclodextrin solution; add nano silica to 3-5 times its total volume of β-cyclodextrin solution and stir evenly to obtain nano silica-β-cyclodextrin agent;

[0018] S12: The nano-silica-β-cyclodextrin agent and the modifier are mixed and ball-milled at a weight ratio of (11-15):7. After ball milling, the mixture is filtered and dried to obtain the modified nano-silica agent.

[0019] Preferably, the sodium silicate solution has a mass fraction of 2-5%.

[0020] Preferably, the modifier is prepared by:

[0021] S121: Add 2-4 parts of nano-calcium carbonate and 1-3 parts of nano-cellulose to 5-8 parts of sodium alginate solution with a mass fraction of 2-5%, then add 2-3 parts of silicon carbide powder, stir evenly, and obtain the initial agent.

[0022] S122: Mix carbon nanotubes and polyurethane at a weight ratio of 2:(11-13), heat and react at 130-135℃ for 2 hours, cool down to 45℃, add water at a weight ratio of 2-3 times the total amount of carbon nanotubes, sonicate thoroughly, and then filter and dry to obtain carbon nanotube agent; stir carbon nanotube agent and primary agent at a weight ratio of 3:(5-7) thoroughly to obtain modifier.

[0023] Preferably, the nano-silica particles have a particle size of 10-40 nm and a specific surface area of ​​200-350 m². / g; carbon nanotubes are multi-walled carbon nanotubes with a diameter of 10-30nm and a length of 5-15μm; nanocellulose has a length of 50-200nm and a diameter of 5-20nm.

[0024] This invention also provides a method for preparing a self-cleaning fluorocarbon topcoat, comprising the following steps:

[0025] S100: Base material dispersion: Add fluorocarbon resin, hydroxyl acrylic resin and solvent to the dispersion tank, stir at 500-600r / min for 15-20min, and mix evenly;

[0026] S200: Functional additives: Add nano-kaolin reinforcing agent, modified nano-silica agent, dispersant, defoamer and leveling agent, disperse at high speed of 1200-1500r / min for 30-40min until fineness ≤20μm;

[0027] S300: Grinding: Grind the dispersion to a fineness of ≤10μm using a sand mill to obtain the topcoat base material;

[0028] S400: Curing and preparation: Add curing agent before use, stir at 300-400r / min for 10-15min, and cure for 25-35min to obtain self-cleaning fluorocarbon topcoat.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] This invention uses fluorocarbon resin and hydroxyl acrylic resin as the matrix, and strengthens them by adding nano-kaolin reinforcing agent and modified nano-silica agent. Functional additives such as defoamer, leveling agent and dispersant are added to harmonize and combine them. Through the synergistic effect of the raw materials, the product has significant effects on high self-cleaning property, strong adhesion, excellent mechanical properties, high weather resistance and corrosion resistance, and the overall coordination of the product is excellent.

[0031] Modified nano-silica, coated with β-cyclodextrin, anchored with silane coupling agents, and combined with multifunctional modifiers, constructs a stable micro-nano hierarchical rough structure on the coating surface, endowing the coating with excellent superhydrophobic properties, high water contact angle, and small roll-off angle. Rainwater can automatically wash away surface dust and dirt, achieving long-term efficient self-cleaning, resistance to dust accumulation and discoloration, and significantly reducing later maintenance costs. Nano-kaolin, after preheating activation, ultrasonic intercalation, liquid phase enhancement, and ball milling composite treatment, has high surface activity and uniform dispersion. Basalt fiber and nano-α-Al O Components such as calcium sulfate whiskers and nanocellulose form a strong interfacial transition layer, which tightly bonds with fluorocarbon resin, hydroxyl acrylic resin, and the substrate, significantly improving the coating's cross-cut adhesion and pull-off adhesion. The coating is less prone to peeling, flaking, and cracking, solving the industry problem of decreased adhesion caused by self-cleaning modification. Nano-kaolin reinforcing agent and modified nano-silica agent synergistically construct a three-dimensional network reinforcement structure of fiber-whisker-nanoparticles, which can simultaneously improve the coating's hardness, impact resistance, wear resistance, and flexibility, achieving a balance between high hardness and high toughness. The coating is scratch-resistant, wear-resistant, impact-resistant, and deformation-resistant, and is not easily damaged under long-term use and external forces, exhibiting excellent mechanical durability. The two functional agents combine... The coating's density is significantly increased, effectively blocking the penetration and erosion of water molecules, oxygen ions, chloride ions, and acid and alkali media. It exhibits strong resistance to corrosive environments such as neutral salt spray, acid, alkali, and salt water. The coating is not prone to blistering, rusting, chalking, or peeling, making it suitable for high-corrosion outdoor and marine heavy-duty anti-corrosion scenarios. The components such as nano zinc oxide, carbon nanotubes, and β-cyclodextrin coating work synergistically to provide UV shielding, resistance to thermo-oxidative aging, and resistance to damp heat degradation. After long-term xenon lamp aging, QUV ultraviolet aging, damp heat aging, and high and low temperature cycling, the coating retains high gloss, exhibits minimal color difference, and shows no chalking or cracking. Its weather resistance and temperature change resistance are outstanding, significantly extending its outdoor service life. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to specific examples. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] This embodiment of a self-cleaning fluorocarbon topcoat comprises, by weight, the following raw materials: 40-50 parts fluorocarbon resin, 5-10 parts hydroxyl acrylic resin, 6-10 parts nano-kaolin reinforcing agent, 4-8 parts modified nano-silica agent, 0.3-0.6 parts defoamer, 0.4-0.8 parts leveling agent, 0.5-1.0 parts dispersant, 8-12 parts curing agent, and 15-25 parts solvent.

[0034] The fluorocarbon resin in this embodiment is FEVE fluorocarbon resin with a fluorine content ≥24%; the curing agent is HDI trimer curing agent; the viscosity of the hydroxyl acrylic resin is 2500-6000cps, the solid content is 70%, the hydroxyl value is 80-100mgKOH / g, the acid value is <8mgKOH / g, and the number average molecular weight Mn is 8000-12000.

[0035] The solvent is a mixture of butyl acetate, xylene, and propylene glycol methyl ether acetate in a weight ratio of 3:2:1; the defoamer is polydimethylsiloxane, the leveling agent is acrylate leveling agent, and the dispersant is ammonium polyacrylate dispersant.

[0036] The preparation method of the nano-kaolin reinforcing agent in this embodiment includes the following steps:

[0037] S01: Preheat the nano-kaolin at 55-60℃ for 1 hour to obtain preheated nano-kaolin; subject the preheated nano-kaolin and reinforcing liquid to ultrasonic reinforcement at a weight ratio of 3:(4-7) to obtain reinforced nano-kaolin liquid.

[0038] The preparation method of the enhancement liquid is as follows:

[0039] S01a: Add 2-4 parts of a 2-5% (w / w) lanthanum chloride solution and 1-3 parts of nano-α-Al O Mix 3-5 parts of pyrophyllite powder and 2-4 parts of sodium citrate solution with a mass fraction of 8-12% evenly to obtain an impregnation solution; immerse basalt fibers in an impregnation solution with a volume of 3-5 times the total volume of the basalt fiber and stir thoroughly to obtain a basalt fiber solution.

[0040] S01b: Mix 2-4 parts sepiolite powder, 1-3 parts potassium feldspar powder and 2-4 parts nano zinc oxide evenly to obtain an additive; mix the additive and basalt fiber liquid in a weight ratio of 3:(5-7) and stir thoroughly to obtain a reinforcing liquid;

[0041] S02: Mix 2-4 parts of quartz, 1-3 parts of calcium sulfate whiskers and 2-4 parts of calcined talc powder evenly to obtain an additive; mix the enhanced nano-kaolin liquid and the additive at a weight ratio of (8-11):5, and ball mill them at a speed of 1000-1500 r / min for 2 hours. After ball milling, filter and dry to obtain the nano-kaolin reinforcing agent.

[0042] The kaolin in this embodiment has a particle size of 30-80 nm and a specific surface area of ​​80-120 m². / g; Nano α-Al O The particle size is 20-50 nm; the diameter of basalt fibers is 5-10 μm and the length is 50-100 μm; the diameter of calcium sulfate whiskers is 1-3 μm and the aspect ratio is 20-40.

[0043] In this embodiment, the ultrasonic power for ultrasonic enhancement treatment is 350-400W, and the ultrasonic time is 1 hour.

[0044] The preparation method of the modified nano-silica agent in this embodiment includes the following steps:

[0045] S11: Mix β-cyclodextrin, sodium silicate solution, 75-85% ethanol solution and silane coupling agent KH550 in a weight ratio of (3-5):2:(8-11):1 to obtain β-cyclodextrin solution; add nano silica to 3-5 times its total volume of β-cyclodextrin solution and stir evenly to obtain nano silica-β-cyclodextrin agent;

[0046] S12: The nano-silica-β-cyclodextrin agent and the modifier are mixed and ball-milled at a weight ratio of (11-15):7. After ball milling, the mixture is filtered and dried to obtain the modified nano-silica agent.

[0047] The sodium silicate solution in this embodiment has a mass fraction of 2-5%.

[0048] The preparation method of the modifier in this embodiment is as follows:

[0049] S121: Add 2-4 parts of nano-calcium carbonate and 1-3 parts of nano-cellulose to 5-8 parts of sodium alginate solution with a mass fraction of 2-5%, then add 2-3 parts of silicon carbide powder, stir evenly, and obtain the initial agent.

[0050] S122: Mix carbon nanotubes and polyurethane at a weight ratio of 2:(11-13), heat and react at 130-135℃ for 2 hours, cool down to 45℃, add water at a weight ratio of 2-3 times the total amount of carbon nanotubes, sonicate thoroughly, and then filter and dry to obtain carbon nanotube agent; stir carbon nanotube agent and primary agent at a weight ratio of 3:(5-7) thoroughly to obtain modifier.

[0051] The nano-silica particles in this embodiment have a particle size of 10-40 nm and a specific surface area of ​​200-350 m². / g; carbon nanotubes are multi-walled carbon nanotubes with a diameter of 10-30nm and a length of 5-15μm; nanocellulose has a length of 50-200nm and a diameter of 5-20nm.

[0052] The preparation method of a self-cleaning fluorocarbon topcoat according to this embodiment includes the following steps:

[0053] S100: Base material dispersion: Add fluorocarbon resin, hydroxyl acrylic resin and solvent to the dispersion tank, stir at 500-600r / min for 15-20min, and mix evenly;

[0054] S200: Functional additives: Add nano-kaolin reinforcing agent, modified nano-silica agent, dispersant, defoamer and leveling agent, disperse at high speed of 1200-1500r / min for 30-40min until fineness ≤20μm;

[0055] S300: Grinding: Grind the dispersion to a fineness of ≤10μm using a sand mill to obtain the topcoat base material;

[0056] S400: Curing and preparation: Add curing agent before use, stir at 300-400r / min for 10-15min, and cure for 25-35min to obtain self-cleaning fluorocarbon topcoat.

[0057] Example 1.

[0058] The self-cleaning fluorocarbon topcoat of this embodiment comprises the following raw materials by weight: 45 parts fluorocarbon resin, 7.5 parts hydroxyl acrylic resin, 8 parts nano kaolin reinforcing agent, 6 parts modified nano silica agent, 0.45 parts defoamer, 0.6 parts leveling agent, 0.75 parts dispersant, 10 parts curing agent, and 17.5 parts solvent.

[0059] The fluorocarbon resin in this embodiment is FEVE fluorocarbon resin with a fluorine content ≥24%; the curing agent is HDI trimer curing agent; the viscosity of the hydroxyl acrylic resin is 3500cps, the solid content is 70%, the hydroxyl value is 90mgKOH / g, the acid value is <8mgKOH / g, and the number average molecular weight Mn is 10000.

[0060] The solvent is a mixture of butyl acetate, xylene, and propylene glycol methyl ether acetate in a weight ratio of 3:2:1; the defoamer is polydimethylsiloxane, the leveling agent is acrylate leveling agent, and the dispersant is ammonium polyacrylate dispersant.

[0061] The preparation method of the nano-kaolin reinforcing agent in this embodiment includes the following steps:

[0062] S01: Preheat the nano-kaolin at 58℃ for 1 hour to obtain preheated nano-kaolin; subject the preheated nano-kaolin and reinforcing liquid to ultrasonic reinforcement at a weight ratio of 3:5.5 to obtain reinforced nano-kaolin liquid.

[0063] The preparation method of the enhancement liquid is as follows:

[0064] S01a: Mix 3 parts of 3.5% lanthanum chloride solution and 2 parts of nano-α-Al O 4 parts of pyrophyllite powder and 3 parts of sodium citrate solution with a mass fraction of 10% were mixed evenly to obtain an impregnation solution; basalt fibers were then impregnated into an impregnation solution with a mass of 4 times their volume and stirred thoroughly to obtain a basalt fiber solution.

[0065] S01b: Mix 3 parts sepiolite powder, 2 parts potassium feldspar powder and 3 parts nano zinc oxide evenly to obtain the additive; mix the additive and basalt fiber liquid at a weight ratio of 3:6 and stir thoroughly to obtain the reinforcing liquid;

[0066] S02: Mix 3 parts quartz, 2 parts calcium sulfate whiskers and 3 parts calcined talc powder evenly to obtain an additive; mix the enhanced nano-kaolin liquid and the additive at a weight ratio of 9:5, and ball mill them at a speed of 1250 r / min for 2 h. After ball milling, filter and dry to obtain the nano-kaolin reinforcing agent.

[0067] The kaolin in this embodiment has a particle size of 55 nm and a specific surface area of ​​100 m². / g; Nano α-Al O The particle size is 35 nm; the basalt fiber diameter is 7.5 μm and the length is 75 μm; the calcium sulfate whiskers have a diameter of 2 μm and an aspect ratio of 30.

[0068] In this embodiment, the ultrasonic power for ultrasonic enhancement processing is 375W, and the ultrasonic time is 1 hour.

[0069] The preparation method of the modified nano-silica agent in this embodiment includes the following steps:

[0070] S11: β-Cyclodextrin, sodium silicate solution, 80% ethanol solution and silane coupling agent KH550 are mixed thoroughly in a weight ratio of 4:2:9:1 to obtain β-Cyclodextrin solution; nano-silica is added to 4 times its total weight of β-Cyclodextrin solution and stirred evenly to obtain nano-silica-β-Cyclodextrin agent.

[0071] S12: The nano-silica-β-cyclodextrin agent and the modifier are mixed and ball-milled at a weight ratio of 13:7. After ball milling, the mixture is filtered and dried to obtain the modified nano-silica agent.

[0072] The sodium silicate solution in this embodiment has a mass fraction of 3.5%.

[0073] The preparation method of the modifier in this embodiment is as follows:

[0074] S121: Add 3 parts of nano-calcium carbonate and 2 parts of nano-cellulose to 6.5 parts of sodium alginate solution with a mass fraction of 3.5%, then add 2.5 parts of silicon carbide powder, stir evenly, and obtain the initial agent;

[0075] S122: Carbon nanotubes and polyurethane are mixed at a weight ratio of 2:12 and heated at 132°C for 2 hours. After cooling to 45°C, 2.5 times the amount of water as carbon nanotubes are added, and the mixture is ultrasonically vibrated until fully oscillated. Then, it is filtered and dried to obtain a carbon nanotube agent. The carbon nanotube agent and the primary agent are stirred at a weight ratio of 3:6 until fully oscillated to obtain a modifier.

[0076] The nano-silica particles in this embodiment have a particle size of 25 nm and a specific surface area of ​​280 m². / g; the carbon nanotubes are multi-walled carbon nanotubes with a diameter of 20nm and a length of 10μm; the nanocellulose has a length of 100nm and a diameter of 10nm.

[0077] The preparation method of a self-cleaning fluorocarbon topcoat according to this embodiment includes the following steps:

[0078] S100: Base material dispersion: Add fluorocarbon resin, hydroxyl acrylic resin and solvent to the dispersion tank, stir at 550 r / min for 18 min, and mix evenly;

[0079] S200: Functional additives: Add nano-kaolin reinforcing agent, modified nano-silica agent, dispersant, defoamer and leveling agent, disperse at 1350r / min for 35min until fineness ≤20μm;

[0080] S300: Grinding: Grind the dispersion to a fineness of ≤10μm using a sand mill to obtain the topcoat base material;

[0081] S400: Curing and preparation: Add curing agent before use, stir at 350r / min for 12.5min, and cure for 30min to obtain self-cleaning fluorocarbon topcoat.

[0082] Example 2.

[0083] The self-cleaning fluorocarbon topcoat of this embodiment comprises the following raw materials by weight: 40 parts fluorocarbon resin, 5 parts hydroxyl acrylic resin, 6 parts nano kaolin reinforcing agent, 4 parts modified nano silica agent, 0.3 parts defoamer, 0.4 parts leveling agent, 0.5 parts dispersant, 8 parts curing agent, and 15 parts solvent.

[0084] The fluorocarbon resin in this embodiment is FEVE fluorocarbon resin with a fluorine content ≥24%; the curing agent is HDI trimer curing agent; the viscosity of the hydroxyl acrylic resin is 2500cps, the solid content is 70%, the hydroxyl value is 80mgKOH / g, the acid value is <8mgKOH / g, and the number average molecular weight Mn is 8000; the solvent is a mixture of butyl acetate, xylene, and propylene glycol methyl ether acetate in a weight ratio of 3:2:1; the defoamer is polydimethylsiloxane, the leveling agent is acrylate leveling agent, and the dispersant is ammonium polyacrylate dispersant.

[0085] The preparation method of the nano-kaolin reinforcing agent in this embodiment includes the following steps:

[0086] S01: Preheat nano-kaolin at 55℃ for 1 hour to obtain preheated nano-kaolin; subject the preheated nano-kaolin and reinforcing liquid to ultrasonic reinforcement at a weight ratio of 3:4 to obtain reinforced nano-kaolin liquid.

[0087] The preparation method of the enhancement liquid is as follows:

[0088] S01a: Mix 2 parts of 2% (w / w) lanthanum chloride solution and 1 part of nano-α-Al O Mix 3 parts of pyrophyllite powder and 2 parts of 8% sodium citrate solution evenly to obtain an impregnation solution; immerse basalt fibers in an impregnation solution three times their total volume and stir thoroughly to obtain basalt fiber solution.

[0089] S01b: Mix 2 parts sepiolite powder, 1 part potassium feldspar powder and 2 parts nano zinc oxide evenly to obtain the additive; mix the additive and basalt fiber liquid at a weight ratio of 3:5 and stir thoroughly to obtain the reinforcing liquid;

[0090] S02: Mix 2 parts quartz, 1 part calcium sulfate whiskers and 2 parts calcined talc powder evenly to obtain an additive; mix the enhanced nano-kaolin liquid and the additive at a weight ratio of 8:5, and ball mill them at a speed of 1000 r / min for 2 h. After ball milling, filter and dry to obtain the nano-kaolin reinforcing agent.

[0091] The kaolin in this embodiment has a particle size of 30 nm and a specific surface area of ​​80 m². / g; Nano α-Al O The particle size is 20 nm; the basalt fiber diameter is 5 μm and the length is 50 μm; the calcium sulfate whiskers have a diameter of 1 μm and an aspect ratio of 20.

[0092] In this embodiment, the ultrasonic power for ultrasonic enhancement processing is 350W, and the ultrasonic time is 1 hour.

[0093] The preparation method of the modified nano-silica agent in this embodiment includes the following steps:

[0094] S11: β-Cyclodextrin, sodium silicate solution, 75% ethanol solution and silane coupling agent KH550 are mixed thoroughly in a weight ratio of 3:2:8:1 to obtain β-Cyclodextrin solution; nano-silica is added to 3 times its total weight of β-Cyclodextrin solution and stirred evenly to obtain nano-silica-β-Cyclodextrin agent.

[0095] S12: Nano-silica-β-cyclodextrin agent and modifier are mixed and ball-milled at a weight ratio of 11:7. After ball milling, the mixture is filtered and dried to obtain modified nano-silica agent.

[0096] The sodium silicate solution in this embodiment has a mass fraction of 2%.

[0097] The preparation method of the modifier in this embodiment is as follows:

[0098] S121: Add 2 parts of nano-calcium carbonate and 1 part of nano-cellulose to 5 parts of sodium alginate solution with a mass fraction of 2%, then add 2 parts of silicon carbide powder, stir evenly, and obtain the initial agent.

[0099] S122: Carbon nanotubes and polyurethane are mixed at a weight ratio of 2:11, heated at 130°C for 2 hours, cooled to 45°C, and then water twice the total weight of carbon nanotubes is added. The mixture is ultrasonically vibrated, filtered, and dried to obtain a carbon nanotube agent. The carbon nanotube agent and the primary agent are stirred at a weight ratio of 3:5 to obtain a modifier.

[0100] In this embodiment, the nano-silica particles have a diameter of 10 nm and a specific surface area of ​​200 m². / g; the carbon nanotubes are multi-walled carbon nanotubes with a diameter of 10nm and a length of 5μm; the nanocellulose has a length of 50nm and a diameter of 5nm.

[0101] The preparation method of a self-cleaning fluorocarbon topcoat according to this embodiment includes the following steps:

[0102] S100: Base material dispersion: Add fluorocarbon resin, hydroxyl acrylic resin and solvent to the dispersion tank, stir at 500 r / min for 15 min, and mix evenly;

[0103] S200: Functional additives: Add nano-kaolin reinforcing agent, modified nano-silica agent, dispersant, defoamer and leveling agent, disperse at 1200r / min for 30min until fineness ≤20μm;

[0104] S300: Grinding: Grind the dispersion to a fineness of ≤10μm using a sand mill to obtain the topcoat base material;

[0105] S400: Curing and preparation: Add curing agent before use, stir at 300r / min for 10min, and cure for 25min to obtain self-cleaning fluorocarbon topcoat.

[0106] Example 3.

[0107] The self-cleaning fluorocarbon topcoat of this embodiment comprises the following raw materials by weight: 50 parts fluorocarbon resin, 10 parts hydroxyl acrylic resin, 10 parts nano kaolin reinforcing agent, 8 parts modified nano silica agent, 0.6 parts defoamer, 0.8 parts leveling agent, 1.0 part dispersant, 12 parts curing agent, and 25 parts solvent.

[0108] The fluorocarbon resin in this embodiment is FEVE fluorocarbon resin with a fluorine content ≥24%; the curing agent is HDI trimer curing agent; the hydroxyl acrylic resin has a viscosity of 6000cps, a solid content of 70%, a hydroxyl value of 100mgKOH / g, an acid value <8mgKOH / g, and a number-average molecular weight Mn of 12000.

[0109] The solvent is a mixture of butyl acetate, xylene, and propylene glycol methyl ether acetate in a weight ratio of 3:2:1; the defoamer is polydimethylsiloxane, the leveling agent is acrylate leveling agent, and the dispersant is ammonium polyacrylate dispersant.

[0110] The preparation method of the nano-kaolin reinforcing agent in this embodiment includes the following steps:

[0111] S01: Preheat the nano-kaolin at 60℃ for 1 hour to obtain preheated nano-kaolin; subject the preheated nano-kaolin and reinforcing liquid to ultrasonic reinforcement at a weight ratio of 3:7 to obtain reinforced nano-kaolin liquid.

[0112] The preparation method of the enhancement liquid is as follows:

[0113] S01a: Mix 4 parts of 5% lanthanum chloride solution and 3 parts of nano-α-Al O Mix 5 parts of pyrophyllite powder and 4 parts of sodium citrate solution with a mass fraction of 12% evenly to obtain an impregnation solution; immerse basalt fibers in an impregnation solution with a mass of 5 times the total volume of the basalt fiber and stir thoroughly to obtain a basalt fiber solution.

[0114] S01b: Mix 4 parts sepiolite powder, 3 parts potassium feldspar powder and 4 parts nano zinc oxide evenly to obtain the additive; mix the additive and basalt fiber liquid at a weight ratio of 3:7 and stir thoroughly to obtain the reinforcing liquid;

[0115] S02: Mix 4 parts quartz, 3 parts calcium sulfate whiskers and 4 parts calcined talc powder evenly to obtain an additive; mix the enhanced nano-kaolin liquid and the additive at a weight ratio of 11:5 and ball mill them at a speed of 1500 r / min for 2 h. After ball milling, filter and dry to obtain the nano-kaolin reinforcing agent.

[0116] The kaolin in this embodiment has a particle size of 80 nm and a specific surface area of ​​120 m². / g; Nano α-Al O The particle size is 50 nm; the basalt fiber diameter is 10 μm and the length is 100 μm; the calcium sulfate whiskers have a diameter of 3 μm and an aspect ratio of 40.

[0117] In this embodiment, the ultrasonic enhancement process uses an ultrasonic power of 400W and an ultrasonic time of 1 hour.

[0118] The preparation method of the modified nano-silica agent in this embodiment includes the following steps:

[0119] S11: β-Cyclodextrin, sodium silicate solution, 85% ethanol solution and silane coupling agent KH550 are mixed thoroughly in a weight ratio of 5:2:11:1 to obtain β-Cyclodextrin solution; nano-silica is added to 5 times its total weight of β-Cyclodextrin solution and stirred evenly to obtain nano-silica-β-Cyclodextrin agent.

[0120] S12: The nano-silica-β-cyclodextrin agent and the modifier are mixed and ball-milled at a weight ratio of 15:7. After ball milling, the mixture is filtered and dried to obtain the modified nano-silica agent.

[0121] The sodium silicate solution in this embodiment has a mass fraction of 5%.

[0122] The preparation method of the modifier in this embodiment is as follows:

[0123] S121: Add 4 parts of nano-calcium carbonate and 3 parts of nano-cellulose to 8 parts of sodium alginate solution with a mass fraction of 5%, then add 3 parts of silicon carbide powder, stir evenly, and obtain the initial agent.

[0124] S122: Carbon nanotubes and polyurethane are mixed at a weight ratio of 2:13, heated at 135°C for 2 hours, cooled to 45°C, and then water is added in a ratio of 3 times the total weight of carbon nanotubes. The mixture is ultrasonically vibrated, filtered, and dried to obtain a carbon nanotube agent. The carbon nanotube agent and the primary agent are stirred at a weight ratio of 3:7 to obtain a modifier.

[0125] The nano-silica particles in this embodiment have a particle size of 40 nm and a specific surface area of ​​350 m². / g; the carbon nanotubes are multi-walled carbon nanotubes with a diameter of 30nm and a length of 15μm; the nanocellulose has a length of 200nm and a diameter of 20nm.

[0126] The preparation method of a self-cleaning fluorocarbon topcoat according to this embodiment includes the following steps:

[0127] S100: Base material dispersion: Add fluorocarbon resin, hydroxyl acrylic resin and solvent to the dispersion tank, stir at 600 r / min for 20 min, and mix evenly;

[0128] S200: Functional additives: Add nano-kaolin reinforcing agent, modified nano-silica agent, dispersant, defoamer and leveling agent, disperse at 1500r / min for 40min until fineness ≤20μm;

[0129] S300: Grinding: Grind the dispersion to a fineness of ≤10μm using a sand mill to obtain the topcoat base material;

[0130] S400: Curing and preparation: Add curing agent before use, stir at 400r / min for 15min, and cure for 35min to obtain self-cleaning fluorocarbon topcoat.

[0131] Comparative Example 1.

[0132] Unlike Example 1, no nano-kaolin reinforcing agent was added.

[0133] Comparative Example 2.

[0134] Unlike Example 1, no additives were added in the preparation of the nano-kaolin reinforcing agent.

[0135] Comparative Example 3.

[0136] Unlike Example 1, no conditioning agent was added during the preparation of the reinforcing liquid.

[0137] Comparative Example 4.

[0138] Unlike Example 1, nano-α-Al was not added during the preparation of the basalt fiber liquid. O He Yehua stone powder.

[0139] Comparative Example 5.

[0140] Unlike Example 1, no basalt fibers were added to the basalt fiber liquid.

[0141] Comparative Example 6.

[0142] Unlike Example 1, no modified nano-silica agent was added.

[0143] Comparative Example 7.

[0144] Unlike Example 1, no modifier was added in the preparation of the modified nano silica agent.

[0145] Comparative Example 8.

[0146] Unlike Example 1, no carbon nanotube agent was added during the preparation of the modifier.

[0147] Comparative Example 9.

[0148] Unlike Example 1, the carbon nanotube agent is directly replaced by carbon nanotubes.

[0149] Comparative Example 10.

[0150] Unlike Example 1, nano-calcium carbonate and nano-cellulose were not added in the preparation of the primary agent.

[0151] The products of Examples 1-3 and Comparative Examples 1-10 were subjected to performance tests, and the test methods are as follows;

[0152] Self-cleaning: Water contact angle GB / T30693-2014; Stain resistance GB / T9780; Adhesion: Cross-cut test GB / T9286-2021; Pull-off test GB / T5210; Mechanical properties: Hardness GB / T6739; Impact resistance GB / T1731; Abrasion resistance GB / T1768; Flexibility GB / T1731; Corrosion resistance: Neutral salt spray GB / T10125; Acid / alkali / salt water resistance GB / T9274; Weather resistance: Xenon lamp GB / T1865; QUV ultraviolet light GB / T23987; Damp heat GB / T1740, temperature 47℃, relative humidity 96%, continuous for 500h; Stability: High and low temperature cycling, low temperature: -30℃, hold for 1h, high temperature: 80℃, hold for 1h, cycle 100 times; Test results are as follows:

[0153] Table 1 Self-cleaning properties and adhesion

[0154] Group Water contact angle (°) Stain resistance (%) Grid (level) Pull apart (MPa) Example 1 112.6 4.2 0 5.8 Example 2 108.3 5.5 0 5.2 Example 3 115.8 3.6 0 6.3 Comparative Example 1 82.5 16.8 3 2.1 Comparative Example 2 91.3 12.5 2 3.2 Comparative Example 3 94.7 10.1 2 3.6 Comparative Example 4 96.2 9.3 1 4.1 Comparative Example 5 95.8 9.7 1 3.9 Comparative Example 6 85.3 15.2 2 2.6 Comparative Example 7 90.5 13.6 2 3.3 Comparative Example 8 93.2 11.2 1 4.0 Comparative Example 9 92.1 12.1 1 3.7 Comparative Example 10 94.3 10.5 1 3.8

[0155] Table 2 Mechanical Properties

[0156] Group Pencil hardness Impact resistance (kg・cm) Abrasion resistance (mg) Flexibility (mm) Example 1 3H 50 18.6 1 Example 2 3H 45 22.3 1 Example 3 3H 55 15.7 1 Comparative Example 1 H 30 42.5 3 Comparative Example 2 2H 38 31.2 2 Comparative Example 3 2H 40 28.5 2 Comparative Example 4 2H 42 26.3 2 Comparative Example 5 2H 41 27.1 2 Comparative Example 6 H 32 39.8 3 Comparative Example 7 2H 36 33.1 2 Comparative Example 8 2H 43 25.7 2 Comparative Example 9 2H 39 29.4 2 Comparative Example 10 2H 44 24.9 2

[0157] Table 3 Corrosion resistance (1000h)

[0158] Group neutral salt spray 5% sulfuric acid (500h) 5% NaOH (500h) 3% NaCl (1000h) Example 1 Rust-free, bubble-free, and peeling-free No abnormalities No abnormalities No abnormalities Example 2 Rust-free, bubble-free, and peeling-free No abnormalities No abnormalities No abnormalities Example 3 Rust-free, bubble-free, and peeling-free No abnormalities No abnormalities No abnormalities Comparative Example 1 Severe corrosion, extensive blistering Loss of luster, cracking Bubbling, peeling Severe corrosion Comparative Example 2 Slight blistering, minor rust Slight loss of light Slight discoloration Slight bubbling Comparative Example 3 Slight bubbling Slight loss of light Slight color change microbubbles Comparative Example 4 Microbubbles normal normal No abnormalities Comparative Example 5 microbubbles normal normal Microbubbles Comparative Example 6 Obvious rust and blistering Powdering, loss of gloss Peeling Noticeable bubbling Comparative Example 7 Slight bubbling Slight loss of light Slight color change microbubbles Comparative Example 8 Microbubbles normal normal No abnormalities Comparative Example 9 microbubbles Slight loss of light normal microbubbles Comparative Example 10 Microbubbles normal normal No abnormalities

[0159] Table 4 Weather resistance and stability

[0160] Group Xenon lamp gloss retention rate (%) after 2000 hours QUV3000hΔE 500 hours of humid heat 100 cycles of high and low temperatures Example 1 92.3 0.8 No abnormalities No abnormalities Example 2 88.6 1.2 No abnormalities No abnormalities Example 3 94.5 0.6 No abnormalities No abnormalities Comparative Example 1 62.1 4.3 Powdering and cracking cracking and peeling Comparative Example 2 76.5 2.4 Slight loss of light No abnormalities Comparative Example 3 79.2 2.1 Slight loss of light No abnormalities Comparative Example 4 83.6 1.6 normal No abnormalities Comparative Example 5 82.1 1.7 normal No abnormalities Comparative Example 6 65.7 3.9 Loss of shine and bubbling cracking Comparative Example 7 74.3 2.6 Slight loss of light No abnormalities Comparative Example 8 84.5 1.5 normal No abnormalities Comparative Example 9 78.8 2.2 Slight loss of light No abnormalities Comparative Example 10 85.1 1.4 normal No abnormalities

[0161] As can be seen from Comparative Examples 1-10 and Examples 1-3;

[0162] Examples 1-3 all exhibit a water contact angle ≥108°, a whiteness reduction rate ≤5.5% in the staining resistance test, a cross-cut adhesion rating of 0, and a pull adhesion ≥5.2MPa, achieving optimal levels of both self-cleaning performance and adhesion. Examples 1-3 also achieve a hardness of 3H, an impact resistance of 45-55 kg·cm, an abrasion resistance ≤22.3 mg, and a flexibility of 1 mm, achieving a balance between high hardness, high abrasion resistance, high impact resistance, and high flexibility.

[0163] The example showed no rust, blistering, peeling, or abnormalities in neutral salt spray, acid resistance, alkali resistance, and salt water resistance tests, demonstrating extremely strong shielding and protection capabilities. After 2000 hours of xenon lamp aging, the gloss retention rate of the example was ≥88.6%, the color difference ΔE was ≤1.2 after 3000 hours of QUV ultraviolet light, and no abnormalities were observed after 500 hours of damp heat and 100 cycles of high and low temperatures, demonstrating excellent weather resistance and temperature change resistance.

[0164] The contact angle of Comparative Example 1 (without nano-kaolin reinforcing agent) and Comparative Example 6 (without modified nano-silica agent) decreased significantly and the adhesion was significantly reduced, indicating that the two functional agents are indispensable and have a significant synergistic effect, which fundamentally solves the technical problem of "improving self-cleaning inevitably reduces adhesion".

[0165] The comparative samples lacking any of the key components such as additives, modifiers, basalt fibers, carbon nanotubes, and nano-calcium carbonate / cellulose all showed a decrease in hardness, a deterioration in wear resistance, a reduction in impact resistance, and a deterioration in flexibility, proving that the fiber-whisker-nanoparticle three-dimensional reinforcement system of the present invention is the key to the comprehensive improvement of mechanical properties.

[0166] The comparative example showed that due to the lack of functional agents or key components, the coating density decreased, and phenomena such as corrosion penetration, blistering, cracking, and loss of gloss appeared. This indicates that nano-kaolin reinforcing agent and modified nano-silica agent can significantly improve the coating density and interfacial bonding force, and give the topcoat excellent acid and alkali resistance, salt spray resistance, and media erosion resistance.

[0167] The comparative examples, lacking UV-shielding components, dispersing components, and interface-modifying components, exhibited significant loss of gloss, discoloration, chalking, and cracking. This demonstrates that the present invention, through multiple modifications and synergistic composite processes, significantly enhances the topcoat's resistance to UV radiation, heat and oxygen, damp heat, and high and low temperature impacts, meeting the requirements for long-term use in extreme outdoor environments. Each component and process is irreplaceable, resulting in a significant overall synergistic effect. All comparative examples lacking only a single functional component or altering a single process showed a significant performance decline. The groups without nano-kaolin reinforcing agents and without modified nano-silica agents showed the most significant performance decline, indicating that these are the core functional components. The remaining comparative examples demonstrate the effectiveness of additives, modifiers, basalt fibers, and nano-α-Al. O Carbon nanotube agents, nano-calcium carbonate / cellulose, etc. are all indispensable synergistic components, working together to achieve the best overall performance in terms of dispersion, reinforcement, toughening, corrosion resistance, weather resistance, and self-cleaning.

[0168] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0169] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A self-cleaning fluorocarbon topcoat, characterized in that, The raw materials, by weight, include: 40-50 parts fluorocarbon resin, 5-10 parts hydroxyl acrylic resin, 6-10 parts nano-kaolin reinforcing agent, 4-8 parts modified nano-silica agent, 0.3-0.6 parts defoamer, 0.4-0.8 parts leveling agent, 0.5-1.0 parts dispersant, 8-12 parts curing agent, and 15-25 parts solvent.

2. The self-cleaning fluorocarbon topcoat according to claim 1, characterized in that, The fluorocarbon resin is FEVE fluorocarbon resin with a fluorine content ≥24%; the hydroxyl acrylic resin has a viscosity of 2500-6000cps, a solid content of 70%, a hydroxyl value of 80-100mgKOH / g, an acid value <8mgKOH / g, and a number-average molecular weight Mn of 8000-12000. The curing agent is an HDI trimer curing agent; the solvent is a mixture of butyl acetate, xylene, and propylene glycol methyl ether acetate in a weight ratio of 3:2:1; the defoamer is polydimethylsiloxane, the leveling agent is an acrylate leveling agent, and the dispersant is an ammonium polyacrylate dispersant.

3. The self-cleaning fluorocarbon topcoat according to claim 1, characterized in that, The preparation method of the nano-kaolin reinforcing agent includes the following steps: S01: Preheat the nano-kaolin at 55-60℃ for 1 hour to obtain preheated nano-kaolin; subject the preheated nano-kaolin and reinforcing liquid to ultrasonic reinforcement at a weight ratio of 3:(4-7) to obtain reinforced nano-kaolin liquid. The preparation method of the enhancement liquid is as follows: S01a: Add 2-4 parts of a 2-5% (w / w) lanthanum chloride solution and 1-3 parts of nano-α-Al O Mix 3-5 parts of pyrophyllite powder and 2-4 parts of sodium citrate solution with a mass fraction of 8-12% evenly to obtain an impregnation solution; immerse basalt fibers in an impregnation solution with a volume of 3-5 times the total volume of the basalt fiber and stir thoroughly to obtain a basalt fiber solution. S01b: Mix 2-4 parts sepiolite powder, 1-3 parts potassium feldspar powder and 2-4 parts nano zinc oxide evenly to obtain an additive; mix the additive and basalt fiber liquid in a weight ratio of 3:(5-7) and stir thoroughly to obtain a reinforcing liquid; S02: Mix 2-4 parts of quartz, 1-3 parts of calcium sulfate whiskers and 2-4 parts of calcined talc powder evenly to obtain an additive; mix the enhanced nano-kaolin liquid and the additive at a weight ratio of (8-11):5, and ball mill them at a speed of 1000-1500 r / min for 2 hours. After ball milling, filter and dry to obtain the nano-kaolin reinforcing agent.

4. The self-cleaning fluorocarbon topcoat according to claim 3, characterized in that: The nano-kaolin has a particle size of 30-80 nm and a specific surface area of ​​80-120 m². / g; Nano α-Al O The particle size is 20-50 nm; the diameter of basalt fibers is 5-10 μm and the length is 50-100 μm; the diameter of calcium sulfate whiskers is 1-3 μm and the aspect ratio is 20-40.

5. The self-cleaning fluorocarbon topcoat according to claim 3, characterized in that: The ultrasonic enhancement treatment has an ultrasonic power of 350-400W and an ultrasonic time of 1 hour.

6. The self-cleaning fluorocarbon topcoat according to claim 1, characterized in that, The preparation method of the modified nano-silica agent includes the following steps: S11: Mix β-cyclodextrin, sodium silicate solution, 75-85% ethanol solution and silane coupling agent KH550 in a weight ratio of (3-5):2:(8-11):1 to obtain β-cyclodextrin solution; add nano silica to 3-5 times its total volume of β-cyclodextrin solution and stir evenly to obtain nano silica-β-cyclodextrin agent; S12: The nano-silica-β-cyclodextrin agent and the modifier are mixed and ball-milled at a weight ratio of (11-15):

7. After ball milling, the mixture is filtered and dried to obtain the modified nano-silica agent.

7. The self-cleaning fluorocarbon topcoat according to claim 6, characterized in that, The sodium silicate solution has a mass fraction of 2-5%.

8. The self-cleaning fluorocarbon topcoat according to claim 6, characterized in that, The method for preparing the modifier is as follows: S121: Add 2-4 parts of nano-calcium carbonate and 1-3 parts of nano-cellulose to 5-8 parts of sodium alginate solution with a mass fraction of 2-5%, then add 2-3 parts of silicon carbide powder, stir evenly, and obtain the initial agent. S122: Mix carbon nanotubes and polyurethane at a weight ratio of 2:(11-13), heat and react at 130-135℃ for 2 hours, cool down to 45℃, add water at a weight ratio of 2-3 times the total amount of carbon nanotubes, sonicate thoroughly, and then filter and dry to obtain carbon nanotube agent; stir carbon nanotube agent and primary agent at a weight ratio of 3:(5-7) thoroughly to obtain modifier.

9. The self-cleaning fluorocarbon topcoat according to claim 8, characterized in that: The nano-silica particles have a particle size of 10-40 nm and a specific surface area of ​​200-350 m². / g; carbon nanotubes are multi-walled carbon nanotubes with a diameter of 10-30nm and a length of 5-15μm; nanocellulose has a length of 50-200nm and a diameter of 5-20nm.

10. A method for preparing a self-cleaning fluorocarbon topcoat as described in any one of claims 1-9, characterized in that, Includes the following steps: S100: Base material dispersion: Add fluorocarbon resin, hydroxyl acrylic resin and solvent to the dispersion tank, stir at 500-600r / min for 15-20min, and mix evenly; S200: Functional additives: Add nano-kaolin reinforcing agent, modified nano-silica agent, dispersant, defoamer and leveling agent, disperse at high speed of 1200-1500r / min for 30-40min until fineness ≤20μm; S300： Grinding: The dispersion is ground in a sand mill to a fineness of ≤10μm to obtain the topcoat base material; S400: Curing and preparation: Add curing agent before use, stir at 300-400r / min for 10-15min, and cure for 25-35min to obtain self-cleaning fluorocarbon topcoat.