Super-hydrophobic polyurea coating with high adhesive force and high mechanical stability as well as preparation method and application of super-hydrophobic polyurea coating

Abstract

The invention discloses a super-hydrophobic polyurea coating with high adhesive force and high mechanical stability as well as a preparation method and application of the super-hydrophobic polyurea coating. According to the preparation method, synergistic use of small-size secondary amine nanoclusters and large-size secondary amine nanoclusters is facilitated, the small-size secondary amine nanoclusters and the large-size secondary amine nanoclusters can form a high-crosslinking-degree polymer network by virtue of a unique steric hindrance type secondary amine structure while the reaction rate of polyurea is reduced and nanoparticles and polyurea are fully mixed, so that the super-hydrophobic polyurea coating is endowed with excellent mechanical properties. Residual siloxane on the surface of the small-size secondary amine nanocluster can cooperate with urea bonds in polyurea to endow the coating with high adhesive force and wide substrate applicability; the latter reacts with an isocyanate component through a secondary amine group on the surface of the latter, and then the latter is firmly embedded into matrix resin, so that the super-hydrophobic polyurea coating is endowed with excellent surface structure stability.

Description

Technical Field

[0001] The present invention relates to the field of coating materials, and in particular to a super-hydrophobic polyurea coating with high adhesion and high mechanical stability, and a preparation method and application thereof. Background Art

[0002] The surface of the coating prepared by superhydrophobic coating has unique wettability, which is attributed to its low surface energy characteristics and fine micro-nano structure. The contact area between it and the droplet is small, which makes the droplet unable to spread on its surface (contact angle greater than 150°) and easily slides on its surface (rolling angle less than 10°), thereby achieving surface waterproof / ice adhesion, self-cleaning and other characteristics. In recent years, superhydrophobic coatings have received extensive attention in the fields of photovoltaics, power transmission and construction. However, traditional superhydrophobic coatings usually face two major problems: first, the micro-nano structure constructed by nanofillers is relatively fragile, and it is easy to be damaged when subjected to external forces, causing the superhydrophobicity of the coating to be lost and the mechanical durability to be poor; second, there is no interaction between the superhydrophobic coating and the substrate, resulting in poor adhesion and limited applicability of the substrate. In response to the above problems, researchers have proposed a variety of solutions, among which the use of hydrophobic nanoparticles combined with polymer resins with excellent adhesion to construct superhydrophobic coatings is considered to be the simplest and most effective strategy. Such as Chinese patent CN113429867A discloses a kind of micro-nano composite super hydrophobic wear-resistant coating and preparation method thereof, by low-density, small-particle micro-nano particles are hydrophobically modified, then the modified micro-nano particles and two other higher density and larger particle size micro-nano particles without hydrophobic modification are respectively mixed with adhesive solution, correspondingly obtain the micro-nano particle mixed solution that solid filler content gradually decreases successively, finally the mixed solution is sprayed on substrate surface successively and solidified into film. Such as Chinese patent CN115873479A discloses a kind of wear-resistant super hydrophobic coating and preparation method thereof, by mixing different micron-level and nanometer-level particles to reach the most dense packing and prepare coating in combination with organic-inorganic hybrid resin. Although the above method is simple and effective, in these methods, nanoparticles are only combined with resin by physical action, and mechanical stability is limited to improve, and the problem of poor adhesion cannot be solved, which has a strong impact on the long-term use of super hydrophobic coating. Therefore, it is of great significance to prepare a super hydrophobic coating with high adhesion and high mechanical stability surface simultaneously.

[0003] Polyurea is a high molecular polymer prepared by the reaction of isocyanate (NCO) components and amino components. Compared with polymer resins commonly used in super-hydrophobic coatings, such as epoxy resins and polyurethane resins, polyurea molecules contain a large number of urea bonds, and the prepared materials have better mechanical properties and are widely used in fields such as explosion resistance, impact resistance and wear resistance. In addition, polyurea can form hydrogen bonds on the surfaces of various substrates and has excellent adhesion. However, the reaction rate of amino and isocyanate groups is too fast, which makes it impossible to fully mix with nanofillers and introduce excellent mechanical properties and adhesion into super-hydrophobic coatings. Therefore, it is necessary to reduce the reaction rate of polyurea and form chemical bonds between hydrophobic particles and high-performance polyurea resins, so as to prepare a super-hydrophobic polyurea coating with high adhesion and high mechanical stability. Summary of the invention

[0004] In view of the deficiencies in the prior art, the primary purpose of the present invention is to provide a method for preparing a super-hydrophobic polyurea coating with high adhesion and high mechanical stability. The preparation method has a simple process and low cost, and a chemical bond can be formed between the hydrophobic nanoparticles and the polyurea resin, which provides an effective and low-cost new strategy for the preparation of a super-hydrophobic polyurea coating with high adhesion and high mechanical stability, and can promote the practical application of super-hydrophobic polyurea coatings in photovoltaics, construction, power transmission and other fields.

[0005] The second object of the present invention is to provide a super-hydrophobic polyurea coating with high adhesion and high mechanical stability prepared by the above preparation method.

[0006] The third object of the present invention is to provide an application of the super-hydrophobic polyurea coating.

[0007] The primary purpose of the present invention is achieved through the following technical solutions: A method for preparing a super-hydrophobic polyurea coating with high adhesion and high mechanical stability comprises the following steps: (1) Preparation of small-sized secondary amine nanoclusters: Under an inert gas environment, 20-30 g of secondary aminosiloxane, 20-40 g of ammonia water, 20-40 g of deionized water and 60-100 mL of solvent were mixed and stirred according to the following mass volume ratio, and the solvent was removed to obtain small-sized secondary amine nanoclusters; (2) Preparation of large-sized nanoclusters: Under an inert gas environment, 20-30 g of tetrafunctional siloxane, 20-50 g of ammonia water, 20-50 g of deionized water and 60-120 mL of solvent were mixed in the following mass-to-volume ratio and stirred for the first time, 20-30 g of trifunctional perfluorosiloxane was added and stirred for the second time, and then 20-40 g of trifunctional secondary aminosiloxane was added and stirred for the third time, centrifuged and dried to obtain large-sized nanoclusters; (3) Preparation of super-hydrophobic polyurea coating: 30-60 parts of isocyanate resin, 10-50 parts of small-sized secondary amine nanoclusters, 20-50 parts of large-sized nanoclusters, and 40-70 parts of solvent are mixed and dispersed in the following weight proportions, and stirred evenly at room temperature to obtain a super-hydrophobic polyurea coating.

[0008] Preferably, the secondary aminosiloxane in step (1) is at least one of N-(n-butyl)-3-aminopropyltrimethoxysilane, N-cyclohexyl-3-aminopropylmethyltrimethoxysilane, N-anilinomethyltriethoxysilane, N-anilinomethyltrimethoxysilane, N-(n-butyl)-3-aminopropyltriethoxysilane and N-(n-butyl)-3-aminopropyltrimethoxysilane.

[0009] Preferably, in step (1), the stirring temperature is 60-80° C. and the stirring time is 8-12 h.

[0010] Preferably, the tetrafunctional siloxane in step (2) is one of tetraethyl silicate and tetramethyl silicate; The trifunctional perfluorosiloxane is at least one of heptadecafluorodecyltrimethoxysilane, tridecafluorodecyltrimethoxysilane and tridecafluorodecyltriethoxysilane; The trifunctional secondary aminosiloxane is at least one of N-(n-butyl)-3-aminopropyltrimethoxysilane, N-cyclohexyl-3-aminopropylmethyltrimethoxysilane, N-anilinomethyltriethoxysilane, N-anilinomethyltrimethoxysilane, N-(n-butyl)-3-aminopropyltriethoxysilane, and N-(n-butyl)-3-aminopropyltrimethoxysilane.

[0011] Preferably, the particle size of the large-sized nanoclusters in step (2) is 50-300 nm.

[0012] Preferably, in step (2), the first stirring time is 12-16 hours, the second stirring time is 4-6 hours, the third stirring time is 4-6 hours, the first stirring, second stirring and third stirring temperatures are 60-80°C, and the drying temperature is 40-60°C.

[0013] Preferably, the mass concentration of the ammonia water in step (1) and step (2) is 25-28%.

[0014] Preferably, the isocyanate resin in step (3) is at least one of PM200, PM400 and NCO-terminated linear polyurea prepolymer.

[0015] Preferably, the stirring time in step (3) is 1 h.

[0016] Preferably, the solvent in step (1), step (2) and step (3) is at least one of anhydrous ethanol, tetrahydrofuran, dimethylformamide, dimethylacetamide and xylene.

[0017] Preferably, the xylene is one of o-xylene, m-xylene or p-xylene.

[0018] The second object of the present invention is achieved by the following technical solutions: A super-hydrophobic polyurea coating with high adhesion and high mechanical stability is prepared by the above preparation method.

[0019] The third object of the present invention is achieved by the following technical solutions: A superhydrophobic polyurea coating with high adhesion and high mechanical stability is used in the fields of photovoltaics, power transmission and construction.

[0020] Preferably, the application is specifically: loading a super-hydrophobic polyurea coating with high adhesion and high mechanical stability into a spray gun, spraying it on the upper surface of the substrate, and after the super-hydrophobic polyurea coating is cured, a super-hydrophobic polyurea coating with high adhesion and high mechanical stability is prepared.

[0021] Preferably, the spraying environment temperature is 15-40° C. and the relative humidity is 60-100%.

[0022] Preferably, the thickness of the super hydrophobic polyurea coating with high adhesion and high mechanical stability is 30-300 μm.

[0023] Preferably, the substrate is at least one of wood, concrete, steel plate, copper plate, titanium alloy plate, glass, ceramic, and rubber.

[0024] Working principle of the present invention: The present invention designs and prepares small-sized secondary amine nanoclusters containing secondary amine groups as low-activity amino resin components. The unique sterically hindered secondary amine structure can significantly reduce the reaction rate of polyurea. The nanoclusters can be fully stirred and mixed with isocyanate components at room temperature for more than 1 hour without gelation, which creates the possibility of introducing nanofillers. In addition to the low-surface-energy fluorocarbon chains, the large-sized nanoclusters prepared by the present invention also contain reactive secondary amine groups on the surface, which can react with the isocyanate components and then be firmly embedded in the resin matrix, thereby achieving high surface mechanical stability of the material. In the process of preparing large-sized nanoclusters, the reactive monomers need to be added three times in sequence: the first addition of tetrafunctional siloxane is to fully hydrolyze and condense it to form large-sized inorganic Si-O-Si nanoclusters; the second addition of trifunctional perfluorosiloxane is to modify the nanoclusters to low surface energy; the third addition of trifunctional secondary aminosiloxane is to chemically modify the low-surface-energy nanoclusters again to make their surfaces contain secondary amine groups.

[0025] Compared with the prior art, the present invention has the following advantages and beneficial effects: (1) Although the existing polyurea coating has excellent mechanical properties, it cannot be fully mixed with nanoparticles due to its too fast reaction speed, which results in that this type of high-performance material cannot be used in the field of super-hydrophobic coatings. The present invention designs and prepares small-sized secondary amine nanoclusters containing secondary amine groups as low-activity amino resin components, which significantly reduce its reactivity with isocyanate components and facilitate the full mixing of polyurea and super-hydrophobic nanoparticles. In addition, small-sized secondary amine nanoclusters can cross-link all components into a tight polymer network, significantly improving the mechanical properties and construction convenience of super-hydrophobic coatings.

[0026] (2) The conventional super-hydrophobic coatings in the prior art have poor adhesion and substrate applicability, which severely limits their application scenarios. The small-sized secondary amine nanoclusters synthesized as low-activity amino components in the present invention contain unhydrolyzed siloxane groups on their surfaces, which enable the base resin to form chemical bonds with the surfaces of various substrates, thereby giving the prepared super-hydrophobic polyurea coating high adhesion on various substrates.

[0027] (3) The conventional super-hydrophobic coating in the prior art has poor surface mechanical stability. When subjected to external friction, the micro-nano structure of the coating surface will be destroyed, thereby losing its super-hydrophobicity. The surface of the large-sized nano-clusters synthesized by the present invention as reactive super-hydrophobic nano-particle components is modified by secondary aminosiloxane and contains a group that can react with the isocyanate component. Therefore, it can react chemically with the isocyanate component and then be firmly embedded in the matrix resin, significantly improving the mechanical stability of the super-hydrophobic polyurea coating prepared by the super-hydrophobic polyurea coating.

[0028] (4) The super-hydrophobic polyurea coating with high adhesion and high mechanical stability described in the present invention has universal applicability. The present invention uses polyurea as a base resin, and its molecular chain contains abundant urea bonds, which can form hydrogen bond interactions with a variety of substrates. Hydrogen bonds synergistically interact with the residual siloxane on the surface of small-sized secondary amine nanoclusters, thereby giving the coating high adhesion on a variety of substrates and improving its substrate applicability. It can be used on a variety of substrates such as wood, concrete, steel plates, copper plates, titanium alloy plates, glass, ceramics, rubber, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 TEM image of small-sized secondary amine nanoclusters in Example 1; Figure 2 is a SEM image of the large-sized nanoclusters in Example 1; Figure 3 is a SEM image of the surface of the super-hydrophobic polyurea coating described in Example 1; Figure 4This is an optical image of the liquid on the surface of the superhydrophobic polyurea coating in Example 1; Figure 5 Schematic diagram of the self-cleaning performance of the superhydrophobic polyurea coating in Example 1. DETAILED DESCRIPTION

[0030] The present invention is further described in detail below in conjunction with embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0031] In the examples of the present invention, if the specific conditions are not specified, the conditions recommended by the manufacturer are followed. The raw materials, reagents, etc. used without specifying the manufacturer are all conventional products that can be purchased commercially. The parts described in the following examples are all parts by weight.

[0032] Example 1 A method for preparing a super-hydrophobic polyurea coating with high adhesion and high mechanical stability comprises the following steps: (1) Preparation of small-sized secondary amine nanoclusters: Under nitrogen conditions, 20 g of N-anilinemethyltriethoxysilane, 20 g of ammonia water (25-28 wt%), 20 g of deionized water and 60 mL of anhydrous ethanol were added to a reactor equipped with a temperature control device and a stirring device, and stirred at 60 °C for 12 h. Finally, the solvent ethanol was removed to obtain small-sized secondary amine nanoclusters (low-activity secondary amine nanoclusters). (2) Preparation of large-sized nanoclusters: Under nitrogen conditions, 20 g of tetraethyl silicate, 20 g of ammonia water (25-28 wt%), 20 g of deionized water and 60 mL of anhydrous ethanol were added to a reactor equipped with a temperature control device and a stirring device, and stirred at 60 °C for 12 h. Then, 20 g of heptadecafluorodecyltrimethoxysilane was added and stirring continued for 4 hours; then, 20 g of N-anilinomethyltriethoxysilane was added to the above reaction solution, and after another 4 hours of reaction, modified superhydrophobic nanoparticles were obtained by centrifugation, and the particles were further dried in a vacuum oven at 40 °C to obtain the final product, large-sized nanoclusters; (3) Preparation of superhydrophobic polyurea coating: 30 g of large-sized nanoclusters, 10 g of small-sized secondary amine nanoclusters, 20 g of PM200 and 60 mL of xylene were added into a dispersion device and stirred at room temperature for 1 h to obtain a uniformly mixed superhydrophobic polyurea coating, i.e., a superhydrophobic polyurea coating with high adhesion and high mechanical stability.

[0033] Specific application of super hydrophobic polyurea coating: add super hydrophobic polyurea coating to manual spraying equipment, spray pressure is 15psi, spray distance is 10~15cm. The sprayed coating is cured at 25℃ for 24h to obtain a super hydrophobic polyurea coating with high adhesion and high mechanical stability.

[0034] Example 2 A method for preparing a super-hydrophobic polyurea coating with high adhesion and high mechanical stability comprises the following steps: (1) Preparation of small-sized secondary amine nanoclusters: Under nitrogen conditions, 20 g of N-(n-butyl)-3-aminopropyltrimethoxysilane, 20 g of ammonia water (25-28 wt%), 20 g of deionized water and 60 mL of anhydrous ethanol were added to a reactor equipped with a temperature control device and a stirring device, and stirred at 65 °C for 12 h. Finally, the solvent ethanol was removed to obtain low-activity secondary amine nanoclusters; (2) Preparation of large-sized nanoclusters: Under nitrogen conditions, 30 g of tetraethyl silicate, 30 g of ammonia water (25-28 wt%), 30 g of deionized water and 80 mL of anhydrous ethanol were added to a reactor equipped with a temperature control device and a stirring device, and stirred at 80 °C for 12 h. Then, 30 g of heptadecafluorodecyltrimethoxysilane was added and the stirring was continued for 4 hours. Subsequently, 40 g of N-(n-butyl)-3-aminopropyltrimethoxysilane was added to the above reaction solution, and after another 4 hours of reaction, modified superhydrophobic nanoparticles were obtained by centrifugation, which were further dried in a vacuum oven at 40 °C to obtain the final product, large-sized nanoclusters.

[0035] (3) Preparation of superhydrophobic polyurea coating: 30 g of large-sized nanoclusters, 10 g of small-sized secondary amine nanoclusters, 20 g of PM200 and 60 mL of xylene were added into a dispersion device and stirred at room temperature for 1 h to obtain a uniformly mixed superhydrophobic polyurea coating, i.e., a superhydrophobic polyurea coating with high adhesion and high mechanical stability.

[0036] Specific application of super hydrophobic polyurea coating: add super hydrophobic polyurea coating to manual spraying equipment, spray pressure is 15psi, spray distance is 10~15cm. The sprayed coating is cured at 25℃ for 24h to obtain a super hydrophobic polyurea coating with high adhesion and high mechanical stability.

[0037] Example 3 A method for preparing a super-hydrophobic polyurea coating with high adhesion and high mechanical stability comprises the following steps: (1) Preparation of small-sized secondary amine nanoclusters: Under nitrogen conditions, 25 g of N-anilinemethyltriethoxysilane, 30 g of ammonia water (25-28 wt%), 20 g of deionized water and 60 mL of anhydrous ethanol were added to a reactor equipped with a temperature control device and a stirring device, and stirred at 80 °C for 8 h. Finally, the solvent ethanol was removed to obtain low-activity secondary amine nanoclusters. (2) Preparation of large-sized nanoclusters: Under nitrogen conditions, 20 g of tetraethyl silicate, 20 g of ammonia water (25-28 wt%), 20 g of deionized water and 60 mL of anhydrous ethanol were added to a reactor equipped with a temperature control device and a stirring device, and stirred at 80 °C for 12 h. Then, 20 g of heptadecafluorodecyltrimethoxysilane was added and the stirring was continued for 4 hours. Subsequently, 30 g of N-anilinomethyltriethoxysilane was added to the above reaction solution, and after another 4 hours of reaction, modified superhydrophobic nanoparticles were obtained by centrifugation, which were further dried in a vacuum oven at 50 °C to obtain the final product, large-sized nanoclusters.

[0038] (3) Preparation of superhydrophobic polyurea coating: 20 g of large-sized nanoclusters, 20 g of small-sized secondary amine nanoclusters, 20 g of PM200 and 60 mL of xylene were added into a dispersion device and stirred at room temperature for 1 h to obtain a uniformly mixed superhydrophobic polyurea coating, i.e., a superhydrophobic polyurea coating with high adhesion and high mechanical stability.

[0039] The specific application of super hydrophobic polyurea coating is to add super hydrophobic polyurea coating to manual spraying equipment, with a spraying pressure of 15 psi and a spraying distance of 10-15 cm. The sprayed coating is cured at 25 °C for 24 h to obtain a super hydrophobic polyurea coating with high adhesion and high mechanical stability.

[0040] Example 4 A method for preparing a super-hydrophobic polyurea coating with high adhesion and high mechanical stability comprises the following steps: (1) Preparation of small-sized secondary amine nanoclusters: Under nitrogen conditions, 30 g of N-cyclohexyl-3-aminopropylmethyltrimethoxysilane, 30 g of ammonia water (25-28 wt%), 40 g of deionized water and 100 mL of anhydrous ethanol were added to a reactor equipped with a temperature control device and a stirring device, and stirred at 70 °C for 10 h. Finally, the solvent ethanol was removed to obtain low-activity secondary amine nanoclusters; (2) Preparation of large-sized nanoclusters: Under nitrogen conditions, 30 g of tetraethyl silicate, 30 g of ammonia water (25-28 wt%), 30 g of deionized water and 100 mL of anhydrous ethanol were added to a reactor equipped with a temperature control device and a stirring device, and stirred at 65 °C for 18 h. Then, 20 g of heptadecafluorodecyltrimethoxysilane was added and the stirring was continued for 6 hours. Subsequently, 20 g of N-cyclohexyl-3-aminopropylmethyltrimethoxysilane was added to the above reaction solution, and after another 6 hours of reaction, modified superhydrophobic nanoparticles were obtained by centrifugation, and the particles were placed in a vacuum oven at 50 °C for further drying to obtain the final product, large-sized nanoclusters.

[0041] (3) Preparation of superhydrophobic polyurea coating: 20 g of large-sized nanoclusters, 20 g of small-sized secondary amine nanoclusters, 20 g of PM200 component and 60 mL of xylene were added into a dispersion device and stirred at room temperature for 1 h to obtain a uniformly mixed superhydrophobic polyurea coating, i.e., a superhydrophobic polyurea coating with high adhesion and high mechanical stability.

[0042] Specific application of super hydrophobic polyurea coating: add super hydrophobic polyurea coating to manual spraying equipment, spray pressure is 15psi, spray distance is 10~15cm. The sprayed coating is cured at 25℃ for 24h to obtain a super hydrophobic polyurea coating with high adhesion and high mechanical stability.

[0043] Example 5 A method for preparing a super-hydrophobic polyurea coating with high adhesion and high mechanical stability comprises the following steps: (1) Preparation of small-sized secondary amine nanoclusters: Under nitrogen conditions, 10 g of N-(n-butyl)-3-aminopropyltrimethoxysilane, 10 g of N-cyclohexyl-3-aminopropylmethyltrimethoxysilane, 20 g of ammonia water (25-28 wt%), 20 g of deionized water and 60 mL of anhydrous ethanol were added to a reactor equipped with a temperature control device and a stirring device, and stirred at 60 °C for 12 h. Finally, the solvent ethanol was removed to obtain low-activity secondary amine nanoclusters; (2) Preparation of large-sized nanoclusters: Under nitrogen conditions, 20 g of tetraethyl silicate, 20 g of ammonia water (25-28 wt%), 20 g of deionized water and 60 mL of anhydrous ethanol were added to a reactor equipped with a temperature control device and a stirring device, and stirred at 70 °C for 10 h. Then 30 g of heptadecafluorodecyltrimethoxysilane was added and the stirring was continued for 5 hours. Subsequently, 30 g of N-(n-butyl)-3-aminopropyltrimethoxysilane was added to the above reaction solution, and after another 5 hours of reaction, modified superhydrophobic nanoparticles were obtained by centrifugation, which were placed in a vacuum oven at 60 °C for further drying to obtain the final product, large-sized nanoclusters.

[0044] (3) Preparation of superhydrophobic polyurea coating: 20 g of large-sized nanoclusters, 20 g of small-sized secondary amine nanoclusters, 20 g of PM400 and 60 mL of xylene were added into a dispersion device and stirred at room temperature for 1 h to obtain a uniformly mixed superhydrophobic polyurea coating, i.e., a superhydrophobic polyurea coating with high adhesion and high mechanical stability.

[0045] The specific application of the super hydrophobic polyurea coating is as follows: the super hydrophobic polyurea coating is added to the manual spraying equipment, the spraying pressure is 15 psi, and the spraying distance is 10-15 cm. The sprayed coating is cured at 25 ° C for 24 h to obtain a super hydrophobic polyurea coating with high adhesion and high mechanical stability.

[0046] Comparative Example 1 A method for preparing a super-hydrophobic polyurea coating comprises the following steps: (1) Preparation of large-sized nanoclusters: Under nitrogen conditions, 20 g of tetraethyl silicate, 20 g of ammonia water (25-28 wt%), 20 g of deionized water and 60 mL of anhydrous ethanol were added to a reactor equipped with a temperature control device and a stirring device, and stirred at 60 °C for 12 h. Then, 20 g of heptadecafluorodecyltrimethoxysilane was added and stirring was continued for 4 hours. Subsequently, 20 g of N-(n-butyl)-3-aminopropyltrimethoxysilane was added to the above reaction solution, and after another 4 hours of reaction, modified superhydrophobic nanoparticles were obtained by centrifugation, and the particles were further dried in a vacuum oven at 40 °C to obtain the final product. (2) Preparation of superhydrophobic polyurea coating: 40 g of large-sized secondary amine nanoclusters, 20 g of isocyanate component and 60 mL of xylene were added into a dispersion device and stirred at room temperature for 1 h to obtain a uniformly mixed composite coating.

[0047] The specific application of the super hydrophobic polyurea coating is as follows: the super hydrophobic polyurea coating is added to a manual spraying device, and a polyurea coating is prepared by spraying, wherein the spraying pressure is 15 psi and the spraying distance is 10 to 15 cm.

[0048] Comparative Example 2 A method for preparing a super-hydrophobic polyurea coating comprises the following steps: (1) Preparation of small-sized secondary amine nanoclusters: Under nitrogen conditions, 10 g of N-(n-butyl)-3-aminopropyltrimethoxysilane, 10 g of N-cyclohexyl-3-aminopropylmethyltrimethoxysilane, 20 g of ammonia water (25-28 wt%), 20 g of deionized water and 60 mL of anhydrous ethanol were added to a reactor equipped with a temperature control device and a stirring device, and stirred at 60 °C for 8 h. Finally, the solvent ethanol was removed to obtain low-activity secondary amine nanoclusters; (2) Preparation of large-sized nanoclusters: Under nitrogen conditions, 20 g of tetraethyl silicate, 20 g of ammonia water (25-28 wt%), 20 g of deionized water and 60 mL of anhydrous ethanol were added to a reactor equipped with a temperature control device and a stirring device, and stirred at 60 °C for 12 h. Then 20 g of heptadecafluorodecyltrimethoxysilane was added and stirring was continued for 8 hours. Superhydrophobic nanoparticles without secondary amines were obtained by centrifugation and further dried in a vacuum oven at 40 °C to obtain the final product; (3) Preparation of superhydrophobic polyurea coating: 30 g of large-sized nanoclusters without secondary amine, 10 g of small-sized secondary amine nanoclusters, 20 g of isocyanate component and 60 mL of xylene were added into a dispersion device and stirred at room temperature for 1 h to obtain a uniformly mixed superhydrophobic polyurea coating.

[0049] The specific application of the super hydrophobic polyurea coating is as follows: the super hydrophobic polyurea coating is added to a manual spraying device, and a polyurea coating is prepared by spraying, wherein the spraying pressure is 15 psi and the spraying distance is 10 to 15 cm.

[0050] The properties of the super-hydrophobic polyurea coatings prepared in Examples 1 to 5 and Comparative Examples 1 to 2 were tested under the following test conditions: Sandpaper friction test: Use the sandpaper grinding method to press the glass sheet coated with super hydrophobic coating on the gauze paper with a weight, and push the glass sheet to make the coating and sandpaper rub. Use 1000 mesh sandpaper, 330KPa pressure, and rub a distance of 10 cm as one cycle. Test the rolling angle and contact angle after each cycle. Stop the experiment when the rolling angle is greater than 10° or the contact angle is less than 150°.

[0051] Tape peeling resistance test: The limiting oxygen index (LOI) of the samples of Examples 1 to 5 was measured by an oxygen index tester (JF-3, Nanjing Analytical Instrument Co., Ltd., China).

[0052] Adhesion test (ISO 2409-2007): Highest adhesion level 0.

[0053] The results are shown in Table 1 below: Table 1: Adhesion test of materials prepared in Examples 1 to 5 Table 2: Surface mechanical stability test of materials prepared in Examples 1 to 5 .

Claims

1. A method for preparing a super-hydrophobic polyurea coating with high adhesion and high mechanical stability, characterized in that: The following steps are included: (1) Preparation of small-sized secondary amine nanoclusters: Under an inert gas environment, 20-30 g of secondary aminosiloxane, 20-40 g of ammonia water, 20-40 g of deionized water and 60-100 mL of solvent were mixed and stirred in the following mass-to-volume ratio, and the solvent was removed to obtain small-sized secondary amine nanoclusters; (2) Preparation of large-sized nanoclusters: Under an inert gas environment, 20-30 g of tetrafunctional siloxane, 20-50 g of ammonia water, 20-50 g of deionized water and 60-120 mL of solvent were mixed in the following mass-to-volume ratio and stirred for the first time, 20-30 g of trifunctional perfluorosiloxane was added and stirred for the second time, and then 20-40 g of trifunctional secondary aminosiloxane was added and stirred for the third time, centrifuged and dried to obtain large-sized nanoclusters; (3) Preparation of super-hydrophobic polyurea coating: 30-60 parts of isocyanate resin, 10-50 parts of small-sized secondary amine nanoclusters, 20-50 parts of large-sized nanoclusters, and 40-70 parts of solvent are mixed and dispersed in the following weight proportions, and stirred evenly at room temperature to obtain a super-hydrophobic polyurea coating.

2. The method for preparing a super-hydrophobic polyurea coating with high adhesion and high mechanical stability according to claim 1, wherein The secondary aminosiloxane in step (1) is at least one of N-(n-butyl)-3-aminopropyltrimethoxysilane, N-cyclohexyl-3-aminopropylmethyltrimethoxysilane, N-anilinomethyltriethoxysilane, N-anilinomethyltrimethoxysilane, N-(n-butyl)-3-aminopropyltriethoxysilane and N-(n-butyl)-3-aminopropyltrimethoxysilane.

3. The method for preparing a super-hydrophobic polyurea coating with high adhesion and high mechanical stability according to claim 1, wherein The tetrafunctional siloxane in step (2) is one of tetraethyl silicate and tetramethyl silicate; The trifunctional perfluorosiloxane is at least one of heptadecafluorodecyltrimethoxysilane, tridecafluorodecyltrimethoxysilane and tridecafluorodecyltriethoxysilane; The trifunctional secondary aminosiloxane is at least one of N-(n-butyl)-3-aminopropyltrimethoxysilane, N-cyclohexyl-3-aminopropylmethyltrimethoxysilane, N-anilinomethyltriethoxysilane, N-anilinomethyltrimethoxysilane, N-(n-butyl)-3-aminopropyltriethoxysilane, and N-(n-butyl)-3-aminopropyltrimethoxysilane.

4. The method for preparing a super-hydrophobic polyurea coating with high adhesion and high mechanical stability according to claim 1, wherein The particle size of the large-sized nanoclusters described in step (2) is 50-300 nm.

5. The method for preparing a super-hydrophobic polyurea coating with high adhesion and high mechanical stability according to claim 1, characterized in that, In step (2), the first stirring time is 12-16 hours, the second stirring time is 4-6 hours, and the third stirring time is 4-6 hours. The temperatures of the first stirring, the second stirring, and the third stirring are 60-80° C., and the drying temperature is 40-60° C.

6. The method for preparing a super-hydrophobic polyurea coating with high adhesion and high mechanical stability according to claim 1, characterized in that, The mass concentration of the ammonia water in step (1) and step (2) is 25-28%.

7. The method for preparing a super-hydrophobic polyurea coating with high adhesion and high mechanical stability according to claim 1, characterized in that: The isocyanate resin in step (3) is at least one of PM200, PM400 and NCO-terminated linear polyurea prepolymer.

8. The method for preparing a super-hydrophobic polyurea coating with high adhesion and high mechanical stability according to claim 1, characterized in that: The solvent in step (1), step (2) and step (3) is at least one of anhydrous ethanol, tetrahydrofuran, dimethylformamide, dimethylacetamide and xylene.

9. A super hydrophobic polyurea coating with high adhesion and high mechanical stability, characterized in that: Prepared according to the preparation method according to any one of claims 1 to 8.

10. Use of the super hydrophobic polyurea coating with high adhesion and high mechanical stability according to claim 9 in the fields of photovoltaics, power transmission and construction.

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