Super-hydrophobic polyurea coating with high adhesion and mechanical stability, and preparation method and application thereof

Abstract

The application discloses a kind of high adhesion, high mechanical stability super-hydrophobic polyurea coating and its preparation method and application.The application is due to the synergistic use of small size secondary amine nanocluster and large size secondary amine nanocluster, the former can form a high crosslinking degree polymer network by virtue of unique steric secondary amine structure, reduce the polyurea reaction rate, fully mix nanoparticles and polyurea, and give super-hydrophobic polyurea coating excellent mechanical properties.Silicone remaining on the surface of small size secondary amine nanocluster can give the coating high adhesion and wide substrate applicability by synergizing with urea bond in polyurea;The latter is firmly inlaid into matrix resin by reacting with isocyanate component through the secondary amine group on its surface, and gives super-hydrophobic polyurea coating 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] Superhydrophobic coatings (SUHPs) exhibit unique wettability on their surfaces, attributed to their low surface energy and fine micro / nanostructure. This reduces the contact area with liquid droplets, preventing them from spreading (contact angle greater than 150°) and making them prone to sliding (rolling angle less than 10°). This results in surface water repellency, ice adhesion, and self-cleaning properties. In recent years, SUHPs have garnered widespread attention in fields such as photovoltaics, power transmission, and architecture. However, conventional SUHPs typically face two major challenges: First, the micro / nanostructure constructed from nanofillers is relatively fragile and easily damaged by external forces, resulting in a loss of superhydrophobicity and poor mechanical durability. Second, the lack of interaction between SUHPs and substrates results in poor adhesion, limiting their substrate applicability. To address these issues, researchers have proposed various solutions. Among these, the construction of SUHPs using hydrophobic nanoparticles combined with polymer resins with excellent adhesion is considered one of the simplest and most effective strategies. Such as Chinese patent CN113429867A discloses a kind of micro-nano composite super hydrophobic wear-resistant coating and preparation method thereof, by the micro-nano particles of low density, small particle size are carried out hydrophobic modification, then the modified micro-nano particles and two other more high density and larger particle size micro-nano particles without hydrophobic modification are mixed with adhesive solution respectively, the micro-nano particle mixed solution that the corresponding solid filler content is gradually reduced is obtained, and 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-sized particles, reach the most dense packing and prepare coating in combination with organic-inorganic hybrid resin. Although said method is simple and effective, in these methods, nanoparticles only rely on physical action and resin bonding, and mechanical stability improves limited, and the problem that adhesion is poor cannot be solved, has a strong impact on the long-term use of super hydrophobic coating. Therefore, preparation has high adhesion and high mechanical stability surface super hydrophobic coating simultaneously and is of great significance.

[0003] Polyurea is a high-molecular-weight polymer prepared by reacting an isocyanate (NCO) component with an amino component. Compared to polymer resins commonly used in superhydrophobic coatings, such as epoxy resins and polyurethane resins, polyurea molecules contain a large number of urea bonds, resulting in materials with superior mechanical properties. They are widely used in fields such as explosion resistance, impact resistance, and wear resistance. In addition, polyurea can form hydrogen bonds with the surfaces of various substrates, exhibiting excellent adhesion. However, the rapid reaction rate of amino groups with isocyanate groups prevents them from fully mixing with nanofillers, preventing the excellent mechanical properties and adhesion from being introduced into superhydrophobic coatings. Therefore, it is necessary to reduce the reaction rate of polyurea and form chemical bonds between the hydrophobic particles and the high-performance polyurea resin to prepare a superhydrophobic polyurea coating with high adhesion and high mechanical stability. Summary of the Invention

[0004] In view of the shortcomings of 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. It provides an effective and low-cost new strategy for the preparation of super-hydrophobic polyurea coatings with high adhesion and high mechanical stability, which 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:

[0008] A method for preparing a super-hydrophobic polyurea coating with high adhesion and high mechanical stability comprises the following steps:

[0009] (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;

[0010] (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 and stirred for the first time according to the following mass-to-volume ratio. 20-30 g of trifunctional perfluorosiloxane was added and stirred for the second time. 20-40 g of trifunctional secondary aminosiloxane was added and stirred for the third time. The mixture was centrifuged and dried to obtain large-sized nanoclusters.

[0011] (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 were mixed and dispersed according to the following mass parts, and stirred evenly at room temperature to obtain a super-hydrophobic polyurea coating.

[0012] 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.

[0013] Preferably, in step (1), the stirring temperature is 60-80° C., and the stirring time is 8-12 h.

[0014] Preferably, the tetrafunctional siloxane in step (2) is one of tetraethyl silicate and tetramethyl silicate;

[0015] The trifunctional perfluorosiloxane is at least one of heptadecafluorodecyltrimethoxysilane, tridecafluorodecyltrimethoxysilane and tridecafluorodecyltriethoxysilane;

[0016] 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.

[0017] Preferably, the particle size of the large-sized nanoclusters in step (2) is 50-300 nm.

[0018] Preferably, 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 for the first stirring, second stirring, and third stirring are 60-80°C, and the drying temperature is 40-60°C.

[0019] Preferably, the mass concentration of the ammonia water in step (1) and step (2) is 25-28%.

[0020] Preferably, the isocyanate resin in step (3) is at least one of PM200, PM400 and NCO-terminated linear polyurea prepolymer.

[0021] Preferably, the stirring time in step (3) is 1 h.

[0022] Preferably, the solvent in step (1), step (2) and step (3) is at least one of anhydrous ethanol, tetrahydrofuran, dimethylformamide, dimethylacetamide and xylene.

[0023] Preferably, the xylene is one of o-xylene, m-xylene or p-xylene.

[0024] The second object of the present invention is achieved through the following technical solutions:

[0025] A super-hydrophobic polyurea coating with high adhesion and high mechanical stability is prepared by the above preparation method.

[0026] The third object of the present invention is achieved through the following technical solutions:

[0027] A super-hydrophobic polyurea coating with high adhesion and high mechanical stability is used in the fields of photovoltaics, power transmission and construction.

[0028] Preferably, the application is specifically as follows: a super-hydrophobic polyurea coating with high adhesion and high mechanical stability is loaded into a spray gun and sprayed 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.

[0029] Preferably, the spraying environment temperature is 15-40° C. and the relative humidity is 60-100%.

[0030] Preferably, the thickness of the superhydrophobic polyurea coating with high adhesion and high mechanical stability is 30-300 μm.

[0031] Preferably, the substrate is at least one of wood, concrete, steel plate, copper plate, titanium alloy plate, glass, ceramic, and rubber.

[0032] Working principle of the present invention:

[0033] The present invention designs and prepares small-sized secondary amine nanoclusters containing secondary amine groups as low-reactivity amino resin components. Their unique sterically hindered secondary amine structure can significantly reduce the reaction rate of polyurea. They can be fully stirred and mixed with the isocyanate component at room temperature for more than one hour without gel formation, creating the possibility of introducing nanofillers. In addition to containing low-surface-energy fluorocarbon chains, the large-sized nanoclusters prepared by the present invention also contain reactive secondary amine groups on their surfaces. These reactive secondary amine groups can react with the isocyanate component and then be firmly embedded in the resin matrix, thereby imparting high surface mechanical stability to the material. During the preparation of the large-sized nanoclusters, the reactive monomers are added in three steps in sequence: the first step is to add tetrafunctional siloxane to fully hydrolyze and condense it to form large-sized inorganic Si-O-Si nanoclusters; the second step is to add trifunctional perfluorosiloxane to modify the nanoclusters to low surface energy; and the third step is to add trifunctional secondary aminosiloxane to chemically modify the low-surface-energy nanoclusters to contain secondary amine groups on their surfaces.

[0034] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0035] (1) Although existing polyurea coatings have excellent mechanical properties, they cannot be fully mixed with nanoparticles due to their rapid reaction speed, which results in the inability of such high-performance materials to be used in the field of superhydrophobic coatings. The present invention designs and prepares small-sized secondary amine nanoclusters containing secondary amine groups as low-activity amino resin components. This component significantly reduces its reactivity with the isocyanate component, which is conducive to the full mixing of polyurea and superhydrophobic nanoparticles. In addition, the small-sized secondary amine nanoclusters can cross-link all components into a tight polymer network, significantly improving the mechanical properties and construction convenience of the superhydrophobic coating.

[0036] (2) 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 in the present invention as low-activity amino components contain unhydrolyzed siloxane groups on their surfaces, which enable the matrix resin to form chemical bonds with the surfaces of various substrates, thereby giving the prepared super-hydrophobic polyurea coating high adhesion on various substrates.

[0037] (3) Conventional super-hydrophobic coatings in the prior art have poor surface mechanical stability. When subjected to external friction, the micro-nanostructure of the coating surface will be destroyed, thereby losing its super-hydrophobicity. The large-sized nanoclusters synthesized in the present invention as reactive super-hydrophobic nanoparticle components are modified with secondary aminosiloxanes and contain groups that can react with isocyanate components. Therefore, they can chemically react with the isocyanate components 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.

[0038] (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 the base resin, and its molecular chain contains abundant urea bonds, which can form hydrogen bonding interactions with a variety of substrates. The hydrogen bonds synergistically interact with the residual siloxanes on the surface of the 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

[0039] Figure 1 TEM image of small-sized secondary amine nanoclusters in Example 1;

[0040] Figure 2 This is the SEM image of the large-sized nanoclusters in Example 1;

[0041] Figure 3 : This is a SEM image of the surface of the super-hydrophobic polyurea coating described in Example 1;

[0042] Figure 4 This is an optical image of the liquid on the surface of the superhydrophobic polyurea coating in Example 1;

[0043] Figure 5 Schematic diagram of the self-cleaning performance of the superhydrophobic polyurea coating in Example 1. DETAILED DESCRIPTION

[0044] The present invention will be described in further detail below with reference to the embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0045] In the examples of the present invention, if no specific conditions are specified, the reaction was carried out under normal conditions or the conditions recommended by the manufacturer. The raw materials and reagents used without specifying the manufacturer are all conventional products that can be purchased commercially. The parts described in the following examples are all by weight.

[0046] Example 1

[0047] A method for preparing a super-hydrophobic polyurea coating with high adhesion and high mechanical stability comprises the following steps:

[0048] (1) Preparation of small-sized secondary amine nanoclusters: Under nitrogen conditions, 20 g of N-anilinomethyltriethoxysilane, 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);

[0049] (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 heptafluorodecyltrimethoxysilane was added, and stirring was continued for 4 h. Subsequently, 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. The particles were further dried in a vacuum oven at 40 °C to obtain the final product, large-sized nanoclusters.

[0050] (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 to 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.

[0051] Specific application of superhydrophobic polyurea coating: Add superhydrophobic polyurea coating to a manual sprayer at a spray pressure of 15 psi and a spray distance of 10-15 cm. The sprayed coating is cured at 25°C for 24 hours to obtain a superhydrophobic polyurea coating with high adhesion and high mechanical stability.

[0052] Example 2

[0053] A method for preparing a super-hydrophobic polyurea coating with high adhesion and high mechanical stability comprises the following steps:

[0054] (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;

[0055] (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 stirring was continued for 4 h. Subsequently, 40 g of N-(n-butyl)-3-aminopropyltrimethoxysilane was added to the above reaction solution. 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.

[0056] (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 to 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.

[0057] Specific application of superhydrophobic polyurea coating: Add superhydrophobic polyurea coating to a manual sprayer at a spray pressure of 15 psi and a spray distance of 10-15 cm. The sprayed coating is cured at 25°C for 24 hours to obtain a superhydrophobic polyurea coating with high adhesion and high mechanical stability.

[0058] Example 3

[0059] A method for preparing a super-hydrophobic polyurea coating with high adhesion and high mechanical stability comprises the following steps:

[0060] (1) Preparation of small-sized secondary amine nanoclusters: Under nitrogen conditions, 25 g of N-anilinomethyltriethoxysilane, 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;

[0061] (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 stirring was continued for 4 h. 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. The particles were further dried in a vacuum oven at 50 °C to obtain the final product, large-sized nanoclusters.

[0062] (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 to a dispersion device and stirred at room temperature for 1 h to obtain a uniformly mixed superhydrophobic polyurea coating, that is, a superhydrophobic polyurea coating with high adhesion and high mechanical stability.

[0063] The superhydrophobic polyurea coating is applied by hand spraying at a pressure of 15 psi from a distance of 10 to 15 cm. The resulting coating is cured at 25°C for 24 hours to produce a superhydrophobic polyurea coating with high adhesion and mechanical stability.

[0064] Example 4

[0065] A method for preparing a super-hydrophobic polyurea coating with high adhesion and high mechanical stability comprises the following steps:

[0066] (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;

[0067] (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 stirring was continued for 6 h. 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. They were placed in a vacuum oven at 50 °C for further drying to obtain the final product, large-sized nanoclusters.

[0068] (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 to 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.

[0069] Specific application of superhydrophobic polyurea coating: Add superhydrophobic polyurea coating to a manual sprayer at a spray pressure of 15 psi and a spray distance of 10-15 cm. The sprayed coating is cured at 25°C for 24 hours to obtain a superhydrophobic polyurea coating with high adhesion and high mechanical stability.

[0070] Example 5

[0071] A method for preparing a super-hydrophobic polyurea coating with high adhesion and high mechanical stability comprises the following steps:

[0072] (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;

[0073] (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 stirring was continued for 5 h. 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. They were placed in a vacuum oven at 60 °C for further drying to obtain the final product, large-sized nanoclusters.

[0074] (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 to 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.

[0075] The specific application of superhydrophobic polyurea coating is as follows: superhydrophobic polyurea coating is added to a manual spraying device at a spray pressure of 15 psi and a spray distance of 10-15 cm. The sprayed coating is cured at 25°C for 24 hours to obtain a superhydrophobic polyurea coating with high adhesion and high mechanical stability.

[0076] Comparative Example 1

[0077] A method for preparing a super-hydrophobic polyurea coating comprises the following steps:

[0078] (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 heptafluorodecyltrimethoxysilane was added and stirring was continued for 4 h. 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, which were further dried in a vacuum oven at 40 °C to obtain the final product;

[0079] (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 to a dispersion device and stirred at room temperature for 1 h to obtain a uniformly mixed composite coating.

[0080] The specific application of superhydrophobic polyurea coating is as follows: superhydrophobic polyurea coating is added to manual spraying equipment and a polyurea coating is prepared by spraying, wherein the spraying pressure is 15 psi and the spraying distance is 10~15 cm.

[0081] Comparative Example 2

[0082] A method for preparing a super-hydrophobic polyurea coating comprises the following steps:

[0083] (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;

[0084] (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 h. Superhydrophobic nanoparticles without secondary amines were obtained by centrifugation and further dried in a vacuum oven at 40 °C to obtain the final product;

[0085] (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 to a dispersion device and stirred at room temperature for 1 h to obtain a uniformly mixed superhydrophobic polyurea coating.

[0086] The specific application of superhydrophobic polyurea coating is as follows: superhydrophobic polyurea coating is added to manual spraying equipment and a polyurea coating is prepared by spraying, wherein the spraying pressure is 15 psi and the spraying distance is 10~15 cm.

[0087] 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:

[0088] Sandpaper friction test: Using a sandpaper abrasion method, a glass slide coated with a superhydrophobic coating is pressed against a piece of gauze with a weight. The glass slide is then pushed to rub the coating and sandpaper. Using 1000-grit sandpaper and a pressure of 330 kPa, a rubbing distance of 10 cm is considered a cycle. The sliding angle and contact angle are measured after each cycle. The test is terminated when the sliding angle is greater than 10° or the contact angle is less than 150°.

[0089] 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).

[0090] Adhesion test (ISO 2409-2007): Highest adhesion level 0.

[0091] The results are shown in Table 1 below:

[0092] Table 1: Adhesion test of materials prepared in Examples 1 to 5

[0093]

[0094] Table 2: Surface mechanical stability test of materials prepared in Examples 1 to 5

[0095] .

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 and stirred for the first time according to the following mass-to-volume ratio. 20-30 g of trifunctional perfluorosiloxane was added and stirred for the second time. 20-40 g of trifunctional secondary aminosiloxane was added and stirred for the third time. The mixture was 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 were mixed and dispersed according to the following mass parts, and stirred evenly at room temperature to obtain a super-hydrophobic polyurea coating.

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

6. The preparation method of a super-hydrophobic polyurea coating having high adhesion and high mechanical stability according to claim 1, wherein 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 having high adhesion and high mechanical stability according to claim 1, wherein 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 having high adhesion and high mechanical stability according to claim 1, wherein 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.

Images