High-strength super-hydrophobic nano functional coating and preparation method thereof

Abstract

The invention relates to a high-strength super-hydrophobic nano functional coating and a preparation method thereof, belongs to the technical field of coatings, and solves the problems that an existing super-hydrophobic coating is complex in preparation method and poor in mechanical property and corrosion resistance. The high-strength super-hydrophobic nano functional coating comprises the following raw materials in parts by weight: 5-50 parts of a fluorine-containing epoxy copolymer; 50 to 95 parts of epoxy resin; 25 to 37.5 parts of nano silicon dioxide; 12.5 to 25 parts of nano silicon carbide; 20-80 parts of a curing agent; 800 to 2400 parts of a first solvent; the fluorine-containing epoxy copolymer is an acrylate copolymer containing an epoxy group, and the fluorine-containing epoxy copolymer is obtained by copolymerization of fluorine-containing acrylate, acrylate containing an epoxy group and other acrylate monomers. The high-strength super-hydrophobic nano functional coating is high in strength, good in wear resistance and good in corrosion resistance, and the preparation method is simple.

Description

Technical Field

[0001] This invention relates to the field of coating technology, and in particular to a high-strength superhydrophobic nanofunctional coating and its preparation method. Background Technology

[0002] Superhydrophobic coatings have enormous application potential in fields such as anti-icing / de-icing, water collection, oil-water separation, self-cleaning, and corrosion prevention. However, their significant lack of durability greatly hinders the transition of superhydrophobic coatings from the laboratory to practical applications. Surfaces with a water contact angle ≥150° and a water slip angle ≤10° are generally considered superhydrophobic. Constructing micro / nano surface roughening structures and reducing surface energy to minimize the contact between liquid and solid surfaces is an important approach to achieving superhydrophobicity.

[0003] The literature [New J Chem, 2023, 47(13): 6246-57.] discloses a cheap and simple method for preparing a wear-resistant and corrosion-resistant superhydrophobic coating on a steel substrate. The method includes: inserting 3-methacryloyloxypropyltrimethoxysilane (KH570) modified silica particles into the layered spacers formed by the coordination of nano zinc oxide and carboxyl groups in stearic acid, and then preparing a robust and dense superhydrophobic coating by the bonding effect of polytetrafluoroethylene (PTFE). Li et al. [J. Mater. Chem. A, 2015, 3, 13856-13863] introduced fluoroalkylsilane-modified silica nanoparticles into hydroxyl acrylic resin. After crosslinking with polyisocyanate at room temperature, they obtained a superhydrophobic acrylic polyurethane (SAPU) coating with good wear resistance and stable adhesion. The hydrophobic silica nanoparticles were stably anchored in the SAPU resin matrix by the reaction between the silanol groups in the silica nanoparticles and the isocyanate groups in the curing agent. At the same time, a hierarchical micron and nanoscale roughness structure was constructed on the coating surface, resulting in a wear-resistant superhydrophobic coating. Wang et al. [J. Appl. Phys. 2013, 114, 124902] prepared a superhydrophobic surface with excellent mechanical durability and easy repairability based on a polytetrafluoroethylene / room temperature vulcanizing silicone rubber (PTFE / RTVSR) composite material through a simple grinding method. The surface energy of the room temperature vulcanizing silicone rubber matrix decreased with the increase of the volume fraction of PTFE particles, and a rough microstructure was formed on the surface of the composite material through grinding. Water droplets on the surface exhibited a contact angle of approximately 165°±3.4° and a sliding angle of approximately 7.3°±1.9°. However, the above methods all use hydrophobic nanoparticles or first hydrophobize the nanoparticles before mixing them with the film-forming material to prepare the superhydrophobic surface, which is a complex preparation process.

[0004] Liang Xiaolei et al. [Journal of Composite Materials, 2020, 37(08): 1832-40.] achieved superhydrophobicity by doping silica into hydrophobic fluorinated polyacrylate and coating it onto a substrate for curing. However, the superhydrophobic surface prepared by this method is extremely fragile and easily loses its superhydrophobic function when damaged by external mechanical forces, which greatly limits the application scenarios of superhydrophobic coatings. Summary of the Invention

[0005] Based on the above analysis, the present invention aims to provide a high-strength superhydrophobic nanofunctional coating and its preparation method, so as to solve the problems of complex preparation methods and poor mechanical and anti-corrosion properties of existing superhydrophobic coatings.

[0006] On one hand, the present invention provides a high-strength superhydrophobic nanofunctional coating, wherein the high-strength superhydrophobic nanofunctional coating comprises the following raw materials in parts by weight: Fluorinated epoxy copolymer: 5-50 parts; Epoxy resin: 50-95 parts; Nano-silica: 25~37.5 parts; Nano-silicon carbide: 12.5~25 parts; Hardener: 20-80 parts; First solvent: 800~2400 parts; The fluorinated epoxy copolymer is an acrylate copolymer containing epoxy groups, which is obtained by copolymerizing fluorinated acrylate, acrylate containing epoxy groups and other acrylate monomers.

[0007] Optionally, the fluorinated acrylate is at least one of perfluorohexyl ethyl methacrylate, perfluorohexyl ethyl methacrylate, perfluorobutyl ethyl methacrylate, and perfluorobutyl ethyl methacrylate.

[0008] Optionally, the epoxy-containing acrylate is glycidyl methacrylate.

[0009] Optionally, the other acrylate monomers are at least one of butyl acrylate, 2-ethylhexyl acrylate, and isobornyl methacrylate.

[0010] Optionally, the mass ratio of the fluorinated acrylate, the epoxy-containing acrylate, and other acrylate monomers is 1:0.5~1:0.7~2.

[0011] Optionally, the fluorinated epoxy copolymer is prepared by the following steps: mixing an initiator, a fluorinated acrylate, an epoxy-containing acrylate, other acrylate monomers, and a second solvent, reacting at a constant temperature of 70~120℃ for 5~24 hours under a nitrogen protective atmosphere, and then removing the second solvent to obtain the fluorinated epoxy copolymer.

[0012] Optionally, the initiator is at least one of azobisisobutyronitrile, dimethyl azobisisobutyrate, tert-butyl peroxide, and benzoyl peroxide.

[0013] Optionally, the second solvent is butyl acetate and / or ethyl acetate.

[0014] Optionally, the epoxy resin is epoxy resin E-44 and / or epoxy resin E-51.

[0015] Secondly, the present invention also provides a method for preparing the above-mentioned high-strength superhydrophobic nanofunctional coating, the method comprising the following steps: Step (1): Mix the fluorinated epoxy copolymer, epoxy resin and the first solvent, then add nano-silica and nano-silicon carbide, stir and ultrasonically disperse; Step (2): Add a curing agent to the mixture obtained in step (1) to obtain a coating liquid; Step (3): Spray the coating liquid onto the substrate, allow it to dry at room temperature and then cure it to obtain a high-strength superhydrophobic nano-functional coating.

[0016] Compared with the prior art, the present invention can achieve the following beneficial effects: 1. Simple preparation process: This invention directly mixes nanoparticles with hydrophobic film-forming materials, which can be easily sprayed onto various substrates to obtain superhydrophobic nanofunctional coatings.

[0017] 2. High strength and good wear resistance of superhydrophobic coating: Nano silicon carbide has the advantages of high strength and high wear resistance. While forming a micro-nano structure, it can protect nano silicon dioxide. Combined with the high hardness of epoxy resin, the prepared superhydrophobic coating has high strength and good wear resistance.

[0018] 3. Excellent protective performance: The superhydrophobic coating made by using fluorinated epoxy copolymer and epoxy resin as hydrophobic film-forming materials and adding nanoparticles is dense and has high strength, with good corrosion resistance.

[0019] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objectives and other advantages of this invention can be realized and obtained through the description and accompanying drawings, which are particularly pointed out. Attached Figure Description

[0020] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0021] Figure 1 SEM image of the coating surface prepared by the coating liquid in Example 1. Detailed Implementation

[0022] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0023] Existing methods for preparing superhydrophobic coatings all face problems such as complex preparation processes and low strength and wear resistance of the superhydrophobic coatings. Furthermore, in order to achieve a rough surface structure, existing technologies result in loosely packed micro- and nano-particles, reducing the density of the coating and leading to poor corrosion resistance of the prepared superhydrophobic coatings.

[0024] On one hand, the present invention provides a high-strength superhydrophobic nanofunctional coating, wherein the high-strength superhydrophobic nanofunctional coating comprises the following raw materials in parts by weight: Fluorinated epoxy copolymer: 5-50 parts; Epoxy resin: 50-95 parts; Nano-silica: 25~37.5 parts; Nano-silicon carbide: 12.5~25 parts; Hardener: 20-80 parts; First solvent: 800~2400 parts; The fluorinated epoxy copolymer is an acrylate copolymer containing epoxy groups, which is obtained by copolymerizing fluorinated acrylate, acrylate containing epoxy groups and other acrylate monomers.

[0025] Compared with existing technologies, this invention uses both nano-silicon carbide and nano-silica as nanoparticles. Nano-silicon carbide has the advantages of high strength and high wear resistance. While forming a micro-nano structure, it can also protect the nano-silica, resulting in a superhydrophobic coating with high strength and good wear resistance. The fluorinated epoxy copolymer of this invention is obtained by copolymerizing fluorinated acrylate, epoxy-containing acrylate, and other acrylate monomers. The fluorinated acrylate provides hydrophobicity; the epoxy-containing acrylate provides epoxy groups, which can react with the epoxy groups in the epoxy resin to form a dense, high-strength cross-linked network; the role of other acrylate monomers is to enhance the compatibility between the fluorinated acrylate and the epoxy-containing acrylate, reduce the glass transition temperature, and improve the compatibility between the obtained fluorinated epoxy copolymer and the epoxy resin, thereby making the superhydrophobic coating dense, high-strength, and with good corrosion resistance.

[0026] It should be noted that the amount of nano-SiO2 used should not be less than the amount of nano-SiC used. The reason is that the main function of nano-SiO2 is to form a micro-nano rough structure. At the same time, nano-SiO2 is a hydrophobic material, which combines with the hydrophobic matrix to form a superhydrophobic surface. On the other hand, nano-SiC particles have weak interparticle interactions and cannot form micro-nano structures. Moreover, it is more hydrophilic and therefore does not help to form a superhydrophobic surface. However, it has high hardness and can play a role in strengthening the hardness of the coating. When nano-SiC and nano-SiO2 are present at the same time, and the amount of nano-SiC is not greater than the amount of nano-SiO2, the coating can have both superhydrophobicity and high strength.

[0027] For example, the fluorinated acrylate is at least one of perfluorohexyl ethyl methacrylate, perfluorohexyl ethyl methacrylate, perfluorobutyl ethyl methacrylate, and perfluorobutyl ethyl methacrylate.

[0028] For example, the epoxy-containing acrylate is glycidyl methacrylate.

[0029] For example, the other acrylate monomers are one of butyl acrylate, 2-ethylhexyl acrylate, and isobornyl methacrylate.

[0030] For example, the mass ratio of the fluorinated acrylate, the epoxy-containing acrylate, and other acrylate monomers is 1:0.5~1:0.7~2.

[0031] Exemplarily, the fluorinated epoxy copolymer is prepared by the following steps: mixing an initiator, a fluorinated acrylate, an epoxy-containing acrylate, other acrylate monomers, and a second solvent; reacting at a constant temperature of 70-120°C for 5-24 hours under a nitrogen protective atmosphere; and then removing the second solvent to obtain the fluorinated epoxy copolymer. The reaction principle is as follows: the initiator decomposes upon heating to generate free radicals, which initiate the polymerization of double bonds in the fluorinated acrylate, the epoxy-containing acrylate, and other acrylate monomers, ultimately yielding the fluorinated epoxy copolymer.

[0032] For example, the initiator is at least one selected from azobisisobutyronitrile, dimethyl azobisisobutyrate, tert-butyl peroxide, and benzoyl peroxide.

[0033] For example, the amount of the initiator is 1% to 5% of the total mass of the fluorinated acrylate, the epoxy-containing acrylate, and the other acrylate monomers.

[0034] For example, the second solvent is butyl acetate and / or ethyl acetate.

[0035] For example, the amount of the second solvent is 10% to 100% of the total mass of the fluorinated acrylate, the epoxy-containing acrylate, and the other acrylate monomers.

[0036] For example, the method for removing the second solvent is vacuum distillation.

[0037] For example, the average particle size of the nano-silica is 5-20 nm. Nano-silica with an average particle size of less than 5 nm is difficult to obtain and is expensive; while nano-silica with an average particle size of more than 20 nm cannot form micro-nano structures.

[0038] For example, the average particle size of the nano-silicon carbide is 40~100nm. Nano-silicon carbide with an average particle size of less than 40nm is difficult to obtain, while nano-silicon carbide with an average particle size of more than 100nm tends to settle in the system, affecting the coating application.

[0039] For example, the epoxy resin is epoxy resin E-44 and / or epoxy resin E-51.

[0040] For example, the curing agent is at least one of polyetheramine D230, polyetheramine D400, polyamide 650 and amine 651.

[0041] For example, the first solvent is acetone.

[0042] Secondly, the present invention also provides a method for preparing the above-mentioned high-strength superhydrophobic nanofunctional coating, the method comprising the following steps: Step (1): Mix the fluorinated epoxy copolymer, epoxy resin and the first solvent, then add nano-silica and nano-silicon carbide, stir and ultrasonically disperse; Step (2): Add a curing agent to the mixture obtained in step (1) to obtain a coating liquid; Step (3): Spray the coating liquid onto the substrate, allow it to dry at room temperature and then cure it to obtain a high-strength superhydrophobic nano-functional coating.

[0043] Compared with the prior art, the preparation method of the present invention is to directly mix nanoparticles with hydrophobic film-forming materials, which is a simple preparation method.

[0044] For example, the substrate is one of glass sheet, copper sheet, filter paper, cleanroom cloth, and polyimide (PI) film.

[0045] In order to ensure that the raw materials are mixed evenly, the stirring and ultrasonic dispersion in step (1) includes: stirring for 15-30 minutes and then ultrasonically dispersing for 15-30 minutes; repeating the above stirring and ultrasonic steps at least 4 times.

[0046] For example, in step (3), the curing includes: curing at 80~100℃ for 2~3 hours and curing at 120~140℃ for 4~6 hours.

[0047] The following specific embodiments further illustrate the high-strength superhydrophobic nanofunctional coating and its preparation method of the present invention.

[0048] In the following examples, nano-silicon carbide (SiC, 40nm) was purchased from Beijing Mairuida Technology Co., Ltd., with a purity of 99.9% on a metals basis.

[0049] Nano-silica (SiO2, 5~20nm) was purchased from Cabot Corporation, brand name CAB-O-SIL TS620.

[0050] The epoxy resin E-51 was purchased from Nantong Xingchen Synthetic Materials Co., Ltd., and its brand name is Phoenix brand epoxy resin WSR618.

[0051] The epoxy resin E-44 was purchased from Nantong Xingchen Synthetic Materials Co., Ltd., and its brand name is Phoenix brand epoxy resin WSR6101.

[0052] The polyetheramine D230 was purchased from Huntsman, and its brand name is D230.

[0053] The polyetheramine D400 was purchased from Huntsman, and its brand name is D400.

[0054] Synthesis example 1 This synthetic example was used to prepare a fluorinated epoxy copolymer, comprising: adding 0.54 g of dimethyl azobisisobutyrate, 10 g of perfluorohexylethyl methacrylate, 6.58 g of glycidyl methacrylate, 10.86 g of butyl acrylate, and 15 g of butyl acetate to a three-necked flask; reacting under a nitrogen atmosphere at a constant temperature of 90 °C for 5 hours with stirring; after the reaction, removing butyl acetate by vacuum distillation to obtain a transparent fluorinated epoxy copolymer PF1. Gel permeation chromatography analysis revealed that the number-average molecular weight (Mn) of the fluorinated epoxy copolymer PF1 was 33466.

[0055] Synthesis example 2 This synthetic example was used to prepare a fluorinated epoxy copolymer, comprising: adding 0.54 g benzoyl peroxide, 10 g perfluorohexyl ethyl acrylate, 6.58 g glycidyl methacrylate, 15.63 g 2-ethylhexyl acrylate, and 15 g butyl acetate to a three-necked flask; reacting under a nitrogen atmosphere at a constant temperature of 90 °C for 12 hours with stirring; after the reaction, removing butyl acetate by vacuum distillation to obtain a transparent fluorinated epoxy copolymer PF2. Gel permeation chromatography showed that the number average molecular weight (Mn) of the fluorinated epoxy copolymer PF2 was 36434.

[0056] Synthesis example 3 This synthetic example was used to prepare a fluorinated epoxy copolymer, comprising: adding 1.75 g of tert-butyl peroxide, 10 g of perfluorobutyl ethyl methacrylate, 5 g of glycidyl methacrylate, 20 g of isobornyl methacrylate, and 3.5 g of butyl acetate to a three-necked flask; reacting under a nitrogen atmosphere at a constant temperature of 120 °C with stirring for 5 hours; after the reaction, removing butyl acetate by vacuum distillation to obtain a transparent fluorinated epoxy copolymer PF3. Gel permeation chromatography showed that the number average molecular weight (Mn) of the fluorinated epoxy copolymer PF3 was 32476.

[0057] Synthesis example 4 This synthetic example was used to prepare a fluorinated epoxy copolymer, comprising: adding 0.39 g of azobisisobutyronitrile, 10 g of perfluorobutyl ethyl acrylate, 10 g of glycidyl methacrylate, 7 g of butyl acrylate, and 27 g of butyl acetate to a three-necked flask; reacting under a nitrogen atmosphere at a constant temperature of 70 °C for 24 hours with stirring; after the reaction, removing butyl acetate by vacuum distillation to obtain a transparent fluorinated epoxy copolymer PF4. Gel permeation chromatography analysis revealed that the number-average molecular weight (Mn) of the fluorinated epoxy copolymer PF4 was 46491.

[0058] Comparative Synthesis Example 1 Comparative Synthesis Example 1 is similar to Synthesis Example 1, except that glycidyl methacrylate is not added, resulting in a fluorinated copolymer DP1 without epoxy groups.

[0059] Comparative Synthesis Example 2 Comparative Synthesis Example 2 is similar to Synthesis Example 1, except that perfluorohexyl ethyl methacrylate is not added, resulting in a fluorine-free epoxy acrylate copolymer DP2.

[0060] Example 1 This example is used to prepare a coating liquid.

[0061] 25g of fluorinated epoxy copolymer PF1 and 75g of epoxy resin E-51 were dissolved in 1500mL of acetone to obtain a PFE solution. 37.5g of nano-SiO2 and 12.5g of nano-SiC were added to the solution. The mixture was magnetically stirred for 15min and then ultrasonically dispersed for 15min. The stirring and ultrasonic process was repeated 4 times. Then, 50g of curing agent polyetheramine D400 was added. After stirring and ultrasonic dispersion, a coating liquid was obtained.

[0062] Example 2 This embodiment is similar to Example 1, except that the fluorinated epoxy copolymer PF2 prepared in Synthesis Example 2 is used instead of the fluorinated epoxy copolymer PF1 in Example 1, epoxy resin E-44 is used instead of epoxy resin E-51 in Example 1, and polyamide 650 is used as the curing agent at a dosage of 20g. Other raw materials and dosages are shown in Table 1.

[0063] Example 3 Example 3 is similar to Example 1, except that the fluorinated epoxy copolymer PF3 prepared in Synthesis Example 3 is used instead of the fluorinated epoxy copolymer PF1 in Example 1, and the curing agent is polyetheramine D230, with an amount of 80g. Other raw materials and amounts are shown in Table 1.

[0064] Example 4 Example 4 is similar to Example 1, except that the fluorinated epoxy copolymer PF4 prepared in Synthesis Example 4 is used instead of the fluorinated epoxy copolymer PF1 in Example 1, and polyamide 651 is used as the curing agent. Other raw materials and amounts are shown in Table 1.

[0065] Examples 5-6 Examples 5 and 6 are similar to Example 1, except that the raw material composition and proportions are different, as shown in Table 1.

[0066] Comparative Examples 1-4 Comparative Examples 1-4 are similar to Example 1, except that the raw material composition and proportions are different, as shown in Table 1.

[0067] Comparative Example 5 Comparative Example 5 is similar to Example 1, except that the fluorinated copolymer DP1 prepared in Comparative Synthesis Example 1 is used instead of the fluorinated epoxy copolymer PF1 in Example 1.

[0068] Comparative Example 6 Comparative Example 6 is similar to Example 1, except that the fluorinated copolymer DP2 prepared in Comparative Synthesis Example 2 is used instead of the fluorinated epoxy copolymer PF1 in Example 1.

[0069] Table 1

[0070] Preparation Example In this preparation example, the coating liquids of Examples 1-6 and Comparative Examples 1-4 were prepared into coatings. The method was as follows: the coating liquid was sprayed onto the substrate with a spray gun at a pressure of 400 kPa and a distance of 20 cm between the nozzle and the substrate. After surface drying at room temperature for 10 minutes, the coating was cured at 80°C for 2 hours and at 120°C for 4 hours to obtain the corresponding nanofunctional coatings.

[0071] Coating performance test Water droplet angle test: A coating was prepared on a glass slide, and the water droplet contact angle was tested using an SDC-100 optical contact angle meter manufactured by Dongguan Shengding Precision Instruments Co., Ltd.

[0072] Abrasion resistance test: Using a glass plate as a substrate, the superhydrophobic coating surface is placed face down against 400-grit sandpaper. The plate is moved 10cm under a 200g weight, rotated 90°, and then moved another 10cm to complete one cycle. The water contact angle is tested at different positions on the superhydrophobic coating surface every 5 cycles, and the average value is taken. The test is stopped when the angle is below 150°. The abrasion resistance of the coating is evaluated based on the number of abrasion cycles at this point.

[0073] Adhesion test: According to the standard test method B (grid cutting method) of ASTM D3359-23 for the evaluation of adhesion of tape, after the coating is sprayed on the copper sheet and cured, the coating is cut with a grid cutter to make a 6×6 grid (1-2mm spacing). After brush cleaning, tape application and other operations, the adhesion is evaluated with a magnifying glass after peeling. The adhesion level is shown in Table 2.

[0074] Table 2

[0075] Chemical stability test: The glass slides coated with the superhydrophobic coating were successively immersed in hydrochloric acid solution with pH=1 for 24 hours, 3.5wt% NaCl solution for 24 hours, and sodium hydroxide solution with pH=13 for 24 hours. After rinsing with deionized water and drying, the water contact angle was measured. If it exceeded 150°, the coating was judged to have good chemical corrosion resistance.

[0076] Electrochemical corrosion testing: Using a Shanghai Chenhua CHI-604E electrochemical workstation with 3.5 wt% NaCl solution as the electrolyte, Tafel curves and electrochemical impedance spectroscopy (EIS) tests were performed on copper sheets coated with superhydrophobic coatings. Z-view software was used for data fitting and analysis. The corrosion rate (mm·year) was then determined. -1 ) and coating resistance (Ω·cm 2 To evaluate the corrosion resistance of the coating.

[0077] The coating performance test results are shown in Table 3.

[0078] Table 3

[0079] Figure 1 The SEM image of the coating surface prepared by the coating liquid in Example 1 shows that the coating surface has a rough micro-nano structure, which provides a rough surface basis for the superhydrophobic properties.

[0080] As shown in Table 3, in all embodiments of the present invention, the water droplet contact angle of the coating exceeds 150°; under a 200g weight, the coating can withstand more than 200 wear cycles while still maintaining superhydrophobicity; the adhesion reaches or exceeds 4; the chemical stability is good, and no obvious damage was observed after testing; the coating has excellent electrochemical corrosion resistance, with corrosion rates all less than 40 × 10⁻⁶. -6 mm·year -1 The coating impedance is higher than 3.4 × 10⁻⁶. 6 Ω·cm 2 This indicates that the coating has good corrosion resistance.

[0081] Comparative Example 1 is a fluorinated epoxy resin coating without added nanoparticles, with a water droplet contact angle of 110°; its electrochemical corrosion resistance is worse than that of Examples 1-6.

[0082] Comparative Example 2 is a fluorinated epoxy resin coating with added nano-SiO2 but without added nano-SiC. Its water droplet contact angle is 155°, which is a superhydrophobic coating. However, its wear resistance is poor. After several wears (<5 times), the water droplet contact angle drops to below 150°, indicating that without the addition of nano-SiC, the coating has poor wear resistance.

[0083] Comparative Example 3 is a coating with a higher amount of nano-SiC. Its water droplet contact angle is 113°, which does not reach superhydrophobicity. Its electrochemical corrosion resistance is worse than that of Examples 1-6. This indicates that although nano-SiC can enhance its wear resistance, due to its large particle size and hydrophilic properties, excessive addition of nano-SiC prevents the coating from achieving superhydrophobicity and results in poor corrosion resistance.

[0084] Comparative Example 4 is a coating prepared without the addition of fluorinated epoxy polymer. Its water droplet contact angle is 130°, which does not achieve superhydrophobicity. Its electrochemical corrosion resistance is worse than that of Examples 1-6. This indicates that although nano-SiC and nano-SiO2 can form a rough micro-nano structure when epoxy resin is used as the film-forming material, the coating cannot achieve superhydrophobicity and has poor corrosion resistance because it does not contain fluorine.

[0085] Comparative Example 5 shows a coating prepared using a fluorinated copolymer without epoxy groups. Its water droplet contact angle is 155°, making it a superhydrophobic coating. However, its wear resistance is poor. After several wear cycles (<100 cycles), the water droplet angle drops below 150°, and its corrosion resistance is also poor. This indicates that the fluorinated copolymer without epoxy groups cannot crosslink with the epoxy resin to form a dense network. The fluorinated polymer migrates to the surface, forming a phase-separated structure, which affects the coating performance.

[0086] Comparative Example 6 shows a coating prepared using a fluorine-free epoxy acrylate copolymer, with a water droplet contact angle of 132°, which does not achieve superhydrophobicity. The electrochemical corrosion resistance is worse than that of Examples 1-6, indicating that although nano-SiC and nano-SiO2 can form a rough micro-nano structure when only epoxy acrylate copolymer and epoxy resin are used as film-forming materials, the coating cannot achieve superhydrophobicity and has poor corrosion resistance due to the absence of fluorine.

[0087] In addition, the present invention also tested the stain resistance of the coating prepared by the coating liquid of Examples 1-6: a glass was placed at an angle, and the coating liquid of Examples 1-6 was sprayed on its surface and cured to form a coating. Sudan Black powder was randomly sprinkled on the surface, and a syringe filled with water was used to simulate the effect of water flow above. As the water droplets rolled on the surface of the superhydrophobic coating, the Sudan Black powder would fall off the surface. After a period of time, the surface became very clean, indicating that the coating has good stain resistance.

[0088] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-strength superhydrophobic nano-functional coating characterized in that, The high-strength super-hydrophobic nano-functional coating comprises the following raw materials by weight: fluorine-containing epoxy copolymer: 5-50 parts; epoxy resin: 50-95 parts; nano-silicon dioxide: 25-37.5 parts; nano-silicon carbide: 12.5-25 parts; curing agent: 20-80 parts; first solvent: 800-2400 parts; The fluorine-containing epoxy copolymer is an acrylate copolymer containing epoxy groups, and the fluorine-containing epoxy copolymer is obtained by copolymerization of fluorine-containing acrylate, acrylate containing epoxy groups and other acrylate monomers.

2. The high-strength, superhydrophobic nano-functional coating of claim 1, wherein, The fluorine-containing acrylate is at least one of perfluorohexyl ethyl methacrylate, perfluorohexyl ethyl acrylate, perfluorobutyl ethyl methacrylate, and perfluorobutyl ethyl acrylate.

3. The high-strength, superhydrophobic nano-functional coating of claim 1, wherein, The acrylate containing epoxy groups is glycidyl methacrylate.

4. The high-strength, superhydrophobic nano-functional coating of claim 1, wherein, The other acrylate monomer is at least one of butyl acrylate, 2-ethylhexyl acrylate, and isobornyl methacrylate.

5. The high-strength, superhydrophobic nano-functional coating of claim 1, wherein, The mass ratio of the fluorine-containing acrylate, the acrylate containing epoxy groups, and the other acrylate monomer is 1:0.5-1:0.7-2.

6. The high-strength, superhydrophobic nano-functional coating of any one of claims 1 to 5, wherein, The fluorine-containing epoxy copolymer is prepared by the following steps: mixing initiator, fluorine-containing acrylate, acrylate containing epoxy groups, other acrylate monomers and second solvent, reacting at 70-120°C for 5-24 hours under nitrogen protection atmosphere, then removing the second solvent to obtain the fluorine-containing epoxy copolymer.

7. The high-strength, superhydrophobic nano-functional coating of claim 6, wherein, The initiator is at least one of azobis isobutyronitrile, dimethyl azobis isobutyrate, tert-butyl peroxybenzoate, and benzoyl peroxide.

8. The high-strength, superhydrophobic nano-functional coating of claim 6, wherein, The second solvent is butyl acetate and / or ethyl acetate.

9. The high-strength, superhydrophobic nano-functional coating of claim 1, wherein, The epoxy resin is epoxy resin E-44 and / or epoxy resin E-51.

10. A method of preparing a high-strength superhydrophobic nano-functional coating according to any one of claims 1 to 9, characterized in that, The preparation method comprises the following steps: Step (1), mixing the fluorine-containing epoxy copolymer, the epoxy resin and the first solvent, then adding nano-silicon dioxide and nano-silicon carbide thereto, stirring and ultrasonic dispersion; Step (2), adding the curing agent to the mixture obtained in step (1) to obtain a coating liquid; Step (3), spraying the coating liquid on the substrate, air-drying at room temperature, then curing to obtain the high-strength super-hydrophobic nano-functional coating.

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