A kind of polyurea self-repairing waterproof coating and preparation method thereof

Abstract

The present invention relates to the technical field of self-repairing waterproof coatings, and specifically to a polyurea self-repairing waterproof coating and a preparation method thereof, comprising the following raw materials: diisocyanate, polyetheramine, modified dicyclohexylamine, modified nano-titanium nitride, modified nano-silicene, a dispersant, a defoaming agent, a leveling agent, a stabilizer, and ethyl acetate. In the present invention, the modified dicyclohexylamine, modified nano-titanium nitride, and modified nano-silicene synergistically enhance the self-repairing and waterproof properties of the polyurea coating; the modified dicyclohexylamine promotes the formation of a polyurea composite cross-linked structure, providing a carrier support for the modified nano-titanium nitride and the modified nano-silicene; the hydrophilicity of the modified nano-titanium nitride and the super-hydrophobicity of the modified nano-silicene form a complementary structure, providing hydrophobic protection and accelerating the self-repairing reaction through hydrophilic moisture absorption, thereby doubly strengthening the waterproofness of the coating surface and interior, thereby maintaining the integrity of the repair area.

Description

Technical Field

[0001] The present invention relates to the technical field of self-repairing waterproof coatings, and in particular to a polyurea self-repairing waterproof coating and a preparation method thereof. Background Art

[0002] Polyurea, a polymer material formed by the reaction of isocyanates and amines, exhibits excellent mechanical properties, corrosion resistance, and abrasion resistance. Due to its outstanding physical properties, excellent waterproofing characteristics, and rapid curing, it has been widely used in construction, roads, tunnels, water conservancy projects, and marine applications. In practical applications, polyurea waterproof coatings effectively prevent water penetration, protecting substrates and exhibiting excellent water resistance and aging resistance in harsh environments. However, traditional polyurea coatings inevitably develop microcracks or damage during use due to external pressure, impact, and temperature fluctuations. Once cracks appear in the coating, the waterproofing function is significantly affected, leading to damage to the substrate. Furthermore, the durability and waterproofing properties of the coating are particularly important in harsh environmental conditions such as high and low temperatures and humidity fluctuations. Improving the coating's weather resistance, crack resistance, and self-healing ability can significantly extend the coating's service life. This can also improve its waterproofing performance, reduce the need for frequent repairs and replacements, and lower long-term maintenance costs. This is crucial for the protection of critical structures and infrastructure, especially in environments such as underground structures and bridges where long-term, stable waterproofing is required. Therefore, it is very meaningful to develop a polyurea waterproof coating with self-repairing function, which can repair cracks by itself when the coating is damaged, thereby greatly improving the durability and waterproof performance of the coating. Summary of the Invention

[0003] (1) Technical problems to be solved

[0004] The purpose of the present invention is to provide a polyurea self-repairing waterproof coating and a preparation method thereof. By optimizing the material formula of the polyurea self-repairing waterproof coating and combining it with modern nanotechnology, the self-repairing and waterproof properties of the polyurea coating are significantly improved, ensuring that the coating can react quickly and restore the waterproof properties when damaged, ensuring the integrity of the coating, and ultimately improving the practicality and market competitiveness of the polyurea coating.

[0005] (2) Technical solution

[0006] To achieve the above objectives, on the one hand, the present invention provides a polyurea self-repairing waterproof coating, comprising the following raw materials in parts by weight: 25-35 parts of diisocyanate, 20-30 parts of polyetheramine, 10-15 parts of modified dicyclohexylamine, 2-5 parts of modified nano-titanium nitride, 0.5-2 parts of dispersant, 0.1-0.5 parts of defoaming agent, 0.5-2 parts of leveling agent, 0.1-0.5 parts of stabilizer, and 5-10 parts of ethyl acetate;

[0007] The polyurea self-repairing waterproof coating further comprises:

[0008] Modified nanosilicene;

[0009] The modified nano-silicene and diisocyanate are in a weight ratio of 5:(25-35);

[0010] The modified nano-silicene is prepared by vapor-depositing heptafluorodecyltrimethoxysilane on the surface of the nano-silicene. The particle size of the modified nano-silicene is 20-50 nm and the specific surface area is 80-100 m 2 / g;

[0011] The preparation method of the modified nano-silicene comprises:

[0012] S11. Dispersing the nanosilicene in anhydrous ethanol and ultrasonically treating the nanosilicene at a frequency of 40 to 50 kHz at room temperature for 0.5 to 1 hour, followed by vacuum drying at 75 to 85°C for 6 to 8 hours to obtain clean nanosilicene.

[0013] S12. Preheat the cleaned nanosilicene on a hot plate under a nitrogen atmosphere at 105-120°C for 0.5-1 hour. After preheating, place the nanosilicene in a vapor deposition reaction chamber with a controlled airflow rate of 25-40 sccm. Load heptadecafluorodecyltrimethoxysilane into the vapor deposition reactor evaporator at a deposition temperature of 145-155°C. After 1-2 hours of deposition, turn off the heating device and cool to room temperature.

[0014] S13. After the vapor deposition reaction, the modified nano-silicene is removed and washed three times with anhydrous ethanol. The modified nano-silicene is then vacuum dried at a temperature of 65-75°C for 12-15 hours. The modified nano-silicene is then ground into a powder for later use.

[0015] Furthermore, the preparation method of the modified dicyclohexylamine comprises:

[0016] S21. Under nitrogen atmosphere and stirring, dissolve dicyclohexylamine in anhydrous ethanol. Raise the temperature to 50-60°C and stir for 1.5-2 hours. Add epichlorohydrin, ensuring a 1:1 molar ratio of dicyclohexylamine to epichlorohydrin. Continue stirring for 0.5-1 hour, then slowly add 0.1 mol / L sodium hydroxide solution. Allow to react for 4-6 hours to obtain a first mixed solution.

[0017] S22. The first mixed solution is subjected to high-speed centrifugation at a speed of 6000-8000 rpm for 10-15 minutes. The supernatant is subjected to rotary evaporation. The water bath temperature is set to 50-60°C, the system pressure is set to 100-200 mbar, and the rotation speed is set to 80-100 rpm. After recrystallization, modified dicyclohexylamine is obtained, that is, the modified dicyclohexylamine is prepared by introducing epoxy groups on the surface of dicyclohexylamine.

[0018] Furthermore, the preparation method of the modified nano-titanium nitride comprises:

[0019] S31. Nano-titanium nitride was dispersed in a 0.1 mol / L hydrochloric acid solution under stirring and ultrasonicated at a frequency of 40 to 50 kHz for 0.5 to 1 hour at room temperature. The resulting solution was then washed with anhydrous ethanol and then vacuum dried at a temperature of 65 to 75°C for 12 to 15 hours to obtain activated nano-titanium nitride.

[0020] S32. The activated nano-titanium nitride was dispersed in anhydrous ethanol and ultrasonically treated, and sodium dodecylbenzenesulfonate was added, and the ultrasonic frequency was set to 40~50 kHz. The second mixed solution was obtained after ultrasonic treatment at room temperature for 0.5~1h.

[0021] S33 acrylic acid was dissolved in purified water, stirred for 0.5 to 1 h, and then potassium persulfate was slowly added. Stirring was continued for 2 to 4 h, and then the pH value was adjusted to 5.5 to 6.0 using phosphate buffer solution to obtain a third mixed solution;

[0022] S34. The third mixed solution was slowly added to the second mixed solution under stirring to react, the reaction temperature was set to 75~85 ℃, the speed was 400~500 rpm, and the mixture was stirred for 4~6h to obtain a fourth mixed solution;

[0023] S35. The fourth mixed solution is subjected to high-speed centrifugation at a speed of 8,000 to 10,000 rpm for 15 to 20 minutes. The separated solid is washed alternately with anhydrous ethanol and purified water three times and then vacuum dried at a drying temperature of 65 to 75°C for 12 to 15 hours to obtain modified nano-titanium nitride, which is ground into a powder for later use.

[0024] Furthermore, the modified nano-titanium nitride is prepared by covalently grafting polyacrylic acid on the surface of nano-titanium nitride, and the particle size of the modified nano-titanium nitride is 120-150 nm and the specific surface area is 50-70 m 2 / g.

[0025] Furthermore, the dispersant is a compound of γ-aminopropyltriethoxysilane, sodium dodecylbenzenesulfonate and sodium polyacrylate, and the weight ratio of γ-aminopropyltriethoxysilane, sodium dodecylbenzenesulfonate and sodium polyacrylate is (1~0.5):(1~2):(1.5~2).

[0026] Furthermore, the defoaming agent is a compound of polyoxyethylene polyoxypropylene ether and polydimethylsiloxane, and the weight ratio of polyoxyethylene polyoxypropylene ether to polydimethylsiloxane is (1-0.5): (1-1.5).

[0027] Furthermore, the leveling agent is a polyacrylate leveling agent.

[0028] Furthermore, the stabilizer is a compound of dibutyltin dilaurate, ethylenediaminetetraacetic acid and epoxy soybean oil, and the weight ratio of dibutyltin dilaurate, ethylenediaminetetraacetic acid and epoxy soybean oil is (1-2): (0.5-1): (0.5-1).

[0029] On the other hand, based on the same inventive concept, the present invention also provides a method for preparing a polyurea self-repairing waterproof coating, which is applied to the aforementioned polyurea self-repairing waterproof coating, comprising the following steps:

[0030] S41 polyetheramine was added to ethyl acetate under stirring, and diisocyanate and modified dicyclohexylamine were slowly added after stirring for 0.5 to 1h, and the reaction was continued with stirring at room temperature for 2 to 4h to obtain a fifth mixed solution;

[0031] S42. The modified nano-titanium nitride and modified nano-silicene were sequentially added to the fifth mixed solution under stirring, and after stirring for 1 to 2 hours, a dispersant, a defoamer, a leveling agent, a stabilizer was slowly added, and the reaction was continued with stirring at room temperature for 4 to 6 hours to obtain a sixth mixed solution;

[0032] S43. Filter the sixth mixed solution through a 0.5-1 μm filter to obtain a polyurea self-repairing waterproof coating.

[0033] The mechanism of action of the above raw material components is as follows:

[0034] In polyurea self-healing waterproof coatings, the -NCO groups of diisocyanate first undergo addition polymerization with the amino groups (-NH2) of polyetheramine to form a basic cross-linked network structure, providing the coating's basic strength and waterproofing properties. Modified dicyclohexylamine is prepared by introducing epoxy groups (-CH2-O-CH-) onto the surface of dicyclohexylamine. Modified dicyclohexylamine, a chain extender, not only increases the reactivity of isocyanate, but also allows the amino groups (-NH2) on its surface to react with diisocyanate, forming a long-chain polyurea structure. By increasing the molecular chain length, the strength, toughness, and weather resistance of the polyurea coating are further improved. Simultaneously, the epoxy groups (-CH2-O-CH-) on its surface further react with the amino groups (-NH2) on the surface of the polyetheramine to form an epoxy network, increasing the crosslinking degree of the polyurea system and further improving the coating's chemical resistance and self-healing ability. The ring structure also increases the coating's rigidity and enhances its wear resistance. When the coating is damaged, the free -NCO groups in the polyurea system further react with amine groups (-NH2), causing self-repair crosslinking. Simultaneously, the epoxy groups (-CH2-O-CH-) of the modified dicyclohexylamine undergo a ring-opening reaction with the free -NH2 / -NCO groups, healing the coating's microcracks. The cyclic structure of the epoxy groups further improves the coating's weather resistance and prevents crack propagation. The crosslinked polyurea structure provides a stable carrier for the modified nano-titanium nitride and modified nano-silicene, enabling them to be evenly dispersed in the polyurea system. Titanium nitride nanoparticles have high hardness and excellent mechanical strength, which can enhance the wear resistance, impact resistance and chemical corrosion resistance of the coating. Modified nano titanium nitride is prepared by covalently grafting polyacrylic acid on the surface of nano titanium nitride. The grafted polyacrylic acid is a hydrophilic chain segment, which will interact with hydrophilic groups such as amino groups or hydroxyl groups in the polyurea cross-linking structure, further enhancing the interfacial bonding force between the modified nano titanium nitride and the polyurea cross-linking structure, so that the modified nano titanium nitride and the polyurea cross-linking structure can be better combined to form a denser and more uniform coating, thereby reducing the number of micropores on the coating surface and slowing down the rate of water penetration. In addition, the modified nano titanium nitride has a high specific surface area and a small nanoparticle size, and can also fill the micropores and cracks in the coating to prevent water penetration. Nanosilicene is a new type of two-dimensional material with a high specific surface area and excellent chemical stability. Modified nanosilicene is prepared by vapor deposition of heptadecafluorodecyltrimethoxysilane on the surface of nanosilicene. The vapor deposition method enables heptadecafluorodecyltrimethoxysilane molecules to form a highly ordered structure on the surface of nanosilicene, which greatly enhances the water droplet repellency of the coating surface, thereby forming a uniform hydrophobic protective film on the coating surface, so that water droplets form "spherical" water droplets with a large contact angle on the surface, which are not easily absorbed by the coating, thereby further improving the waterproofness of the coating. In addition, modified nanosilicene can also effectively fill the microcracks and micropores in the coating, reducing the path of water penetration.At the same time, nano-titanium nitride itself has strong hydrophobicity, but after being grafted with hydrophilic polyacrylic acid, it forms a hydrophilic-hydrophobic coexisting structure. Therefore, the hydrophilicity of the modified nano-titanium nitride and the super-hydrophobic properties of the modified nano-silicene form a complementary structure in the coating. The surface of the coating is first provided with hydrophobic protection by the modified nano-silicene, reducing the penetration of water droplets. At the same time, the micro-crack area inside the coating is accelerated by the hydrophilic hygroscopic effect of the modified nano-titanium nitride to accelerate the self-repair reaction, so that the waterproofness of the coating surface and interior is doubly enhanced. In addition, the super-hydrophobicity of the surface of the modified nano-silicene gives the coating self-cleaning properties. Water droplets on the surface of the coating can not only avoid water penetration through the "ball effect", but also carry away pollutants on the surface of the coating. When microcracks appear in the polyurea coating, the modified nano-titanium nitride promotes self-repair through its hydrophilicity and hydration, while the modified nano-silicene prevents water from penetrating the cracks through its superhydrophobicity, keeping the cracked area dry and further improving the self-repair efficiency. The synergistic effect of the two gives the coating a strong waterproof ability, especially when subjected to external environmental damage, the coating can quickly recover and maintain its waterproof performance. In short, in the polyurea coating, modified dicyclohexylamine, modified nano-titanium nitride, and modified nano-silicene work together to synergistically enhance the self-repair and waterproof properties of the polyurea coating. Modified dicyclohexylamine, through its powerful cross-linking and chain extension function, forms a cross-linked structure of polyurea structure (-NH-CO-NH-) and epoxy groups, giving the coating better structural strength and elasticity, while promoting the automatic healing of cracks. Modified nano-titanium nitride fills cracks through a self-healing reaction, enhancing the waterproofness of the coating. Modified nano-silicene, through its superhydrophobicity and self-cleaning properties, further enhances the waterproofness and weather resistance of the coating, allowing the coating to provide more durable and stronger waterproof protection when facing different environmental challenges, extending the service life of the coating, and ultimately improving the practicality and market competitiveness of the polyurea coating.

[0035] The dispersant can improve the dispersibility of nanoparticles, prevent precipitation and agglomeration, and enhance the uniformity and stability of the coating. The dispersant of the present invention is a compound of γ-aminopropyltriethoxysilane, sodium dodecylbenzenesulfonate, and sodium polyacrylate. The silyl group (Si-OR) of the γ-aminopropyltriethoxysilane can form covalent bonds with modified nano-titanium nitride and modified nano-silicene, thereby improving the dispersibility of the modified nano-titanium nitride and modified nano-silicene in the coating. At the same time, the amino groups (-NH2) on its surface can form hydrogen bonds with polyurea groups (-NH-CO-NH-), further improving the water resistance and chemical bonding strength of the coating. Sodium dodecylbenzenesulfonate is an anionic surfactant that can reduce surface tension and prevent aggregation of nanoparticles such as modified nano-titanium nitride and modified nano-silicene in the coating. Sodium polyacrylate can improve the dispersibility of the entire system and prevent component sedimentation.

[0036] The main function of a defoamer is to prevent bubbles from forming during the coating application process, improving the coating's surface smoothness and aesthetics. It primarily works by reducing the surface tension of the liquid, thereby destabilizing the foam and preventing its formation and accumulation. The defoamer of the present invention is a compound of polyoxyethylene polyoxypropylene ether and polydimethylsiloxane. The polyoxyethylene polyoxypropylene ether reduces interfacial tension, destabilizing bubbles and preventing foam formation. Polydimethylsiloxane is a low-surface-energy defoamer that quickly breaks surface bubbles, improving the smoothness and uniformity of the coating.

[0037] Leveling agents reduce the surface tension of the coating, improving its fluidity and spreadability, allowing the coating to be evenly distributed after application. The leveling agent of the present invention is a polyacrylate-based leveling agent. By reducing surface tension, it improves the fluidity of the coating, enhances the surface smoothness and gloss of the coating, and reduces sagging and orange peel.

[0038] Stabilizers improve the stability and durability of coatings by inhibiting oxidation, hydrolysis, and photodegradation reactions, preventing deterioration and failure during storage and use, and extending the storage and service life of coatings. The stabilizer of the present invention is a compound of dibutyltin dilaurate, ethylenediaminetetraacetic acid, and epoxy soybean oil. Dibutyltin dilaurate is a catalyst that promotes the addition polymerization reaction of diisocyanates and polyetheramines, increasing the curing speed of the coating while providing thermal stability to prevent runaway reactions during long-term storage. Ethylenediaminetetraacetic acid chelates metal ions, preventing catalyst failure and ensuring the long-term stability of the coating. Epoxidized soybean oil, as a plasticizer, improves the flexibility of the coating and prevents cracking. Its epoxy group (-CH2-O-CH-) can also react with amine groups (-NH2), further improving the weather resistance and self-healing ability of the coating.

[0039] Ethyl acetate is a commonly used organic solvent that can dissolve various organic components in the coating and evaporates quickly during the film-forming process, thereby adjusting the viscosity and fluidity of the coating and making the coating easy to apply and dry.

[0040] (3) Beneficial effects

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] Modified dicyclohexylamine, modified nano-titanium nitride, and modified nano-silicene synergistically enhance the self-healing and waterproof properties of polyurea coatings. Modified dicyclohexylamine, through its powerful cross-linking and chain extension function, forms a composite cross-linked structure of polyurea and epoxy groups, promoting the automatic healing of cracks and effectively preventing water penetration.

[0043] The polyurea composite cross-linked structure provides a stable carrier support for the modified nano-titanium nitride and modified nano-silicene, allowing them to be evenly dispersed in the polyurea system;

[0044] Modified nano-titanium nitride helps form a denser and more uniform coating, reduces the number of micropores on the coating surface, slows down the rate of water penetration, and prevents water penetration;

[0045] Modified nano-silicene forms a uniform hydrophobic protective film, allowing water droplets to form "spherical" droplets with a large contact angle on the surface, thereby improving the waterproofness of the coating and removing pollutants on the coating surface through the "ball effect";

[0046] The hydrophilicity of modified nano-titanium nitride and the super-hydrophobicity of modified nano-silicene form a complementary structure in the coating. The modified nano-silicene first provides hydrophobic protection on the coating surface, reducing water droplet penetration. The micro-crack areas inside the coating are accelerated to self-repair through the hydrophilic and hygroscopic effect of the modified nano-titanium nitride, thus doubly strengthening the waterproofness of the coating surface and interior.

[0047] Modified nano-titanium nitride promotes self-repair reaction through its hydrophilicity and hydration, while modified nano-silicene prevents water from penetrating into cracks through its superhydrophobicity, keeps the crack area dry, improves self-repair efficiency, and maintains the integrity of the repair area. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 This is a SEM image of modified nano-titanium nitride in Example 1 of the present invention;

[0049] Figure 2 This is the SEM image of the modified nano-silicene in Example 1 of the present invention. DETAILED DESCRIPTION

[0050] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0051] The experimental equipment and preparations for the embodiments described below are as follows: electronic balance (Sartorius, Germany), electric constant temperature water bath (Jiangsu Kedao), magnetic stirrer (Shanghai Meiyingpu), ultrasonic analyzer (Shanghai Yixin), high-speed centrifuge (Guangzhou Jidi), vacuum drying oven (Shanghai Jiecheng), muffle furnace (Hangzhou Lantian Instrument), rotary evaporator (Zhengzhou Fangyuan), vapor deposition reactor (Suzhou Neumte), scanning electron microscope (Zeiss, Germany), specific surface area analyzer (Beijing Best Instrument Technology), JC2000C dynamic contact angle meter (Shanghai Metallographic); chemicals and reagents were purchased from Sigma-Aldrich.

[0052] Example 1: This example discloses a polyurea self-repairing waterproof coating, comprising the following raw materials in parts by weight: 30 parts of diisocyanate, 25 parts of polyetheramine, 12.5 parts of modified dicyclohexylamine, 3.5 parts of modified nano-titanium nitride, 1.25 parts of dispersant, 0.3 parts of defoaming agent, 1.25 parts of leveling agent, 0.3 parts of stabilizer, and 12.5 parts of ethyl acetate. The polyurea self-repairing waterproof coating also includes modified nano-silicene, wherein the modified nano-silicene and diisocyanate are in a weight ratio of 5:30. The modified nano-silicene is prepared by vapor deposition of heptafluorodecyltrimethoxysilane on the surface of the nano-silicene. The particle size of the modified nano-silicene is 20-50 nm, and the specific surface area is 80-100 m 2 / g.

[0053] In polyurea self-healing waterproof coatings, the -NCO group of diisocyanate first undergoes addition polymerization with the amino group (-NH2) of polyetheramine to form a high-strength polyurea structure (-NH-CO-NH-), thereby forming a basic cross-linked network structure, providing the basic strength and waterproof properties of the coating. Modified dicyclohexylamine is prepared by introducing epoxy groups (-CH2-O-CH-) on the surface of dicyclohexylamine. Modified dicyclohexylamine is a chain extender that acts as a molecular chain extension, which can not only increase the reactivity of isocyanate, but also the amino groups (-NH2) on its surface can react with diisocyanate to form a long-chain polyurea structure. By increasing the length of the molecular chain, the strength, toughness and weather resistance of the polyurea coating are further improved. At the same time, the epoxy groups (-CH2-O-CH-) on its surface react with the amino groups (-NH2) of polyetheramine to form an epoxy network, thereby generating a new cross-linked structure and increasing the cross-linking degree of the polyurea system. The high-strength polyurea cross-linked structure can effectively isolate moisture, prevent moisture penetration, and avoid moisture corrosion and damage to the underlying coating material, further improving the chemical resistance and self-healing ability of the coating. At the same time, its ring structure also increases the rigidity of the coating and improves the wear resistance of the coating. When the coating is damaged, the free -NCO groups in the polyurea system will further react with the amino groups (-NH2) to undergo self-repair cross-linking. At the same time, the epoxy groups (-CH2-O-CH-) of the modified dicyclohexylamine undergo a ring-opening reaction with the free -NH2 / -NCO groups to heal the microcracks in the coating. The cyclic structure of the epoxy groups also further improves the weather resistance of the coating and prevents crack propagation. The polyurea cross-linking structure provides a stable carrier support for the modified nano-titanium nitride and modified nano-silicene, allowing the two to be evenly dispersed in the polyurea system. Titanium nitride nanoparticles have high hardness and excellent mechanical strength, which can enhance the wear resistance, impact resistance and chemical corrosion resistance of the coating. Modified nano-titanium nitride is prepared by covalently grafting polyacrylic acid on the surface of nano-titanium nitride. Figure 1From the SEM image of modified nano-titanium nitride, it can be seen that the modified nano-titanium nitride has a very obvious dense structure. The grafted polyacrylic acid is a hydrophilic segment, which will interact with hydrophilic groups such as amino groups (-NH2) or hydroxyl groups (-OH) in the polyurea cross-linking structure, further enhancing the interfacial bonding force between the modified nano-titanium nitride and the polyurea cross-linking structure, so that the modified nano-titanium nitride and the polyurea cross-linking structure can be better combined to form a denser and more uniform coating, thereby reducing the number of micropores on the coating surface and slowing down the rate of water penetration. The modified nano-titanium nitride has a high specific surface area and a small nanoparticle size, and can also fill the micropores and cracks in the coating. Through this filling effect, the modified nano-titanium nitride can significantly improve the density of the coating, reduce the water penetration path through the coating, and prevent water penetration. Nano-silicene is a new two-dimensional material with a high specific surface area and excellent chemical stability. Modified nano-silicene is prepared by vapor deposition of heptafluorodecyltrimethoxysilane on the surface of nano-silicene. Figure 2From the SEM image of modified nano-silicene, we can see that the modified nano-silicene has a spherical morphology. The vapor deposition method enables the heptadecafluorodecyltrimethoxysilane molecules to form a highly ordered structure on the surface of the nano-silicene, which greatly enhances the water droplet repellency of the coating surface, thereby forming a uniform hydrophobic protective film on the coating surface, so that water droplets form "spherical" water droplets with a large contact angle on the surface, which are not easily absorbed by the coating, thereby further improving the waterproofness of the coating. At the same time, the modified nano-silicene can also effectively fill the microcracks and micropores in the coating, reducing the path of water penetration. At the same time, nano-titanium nitride itself has strong hydrophobicity, but after being grafted with hydrophilic polyacrylic acid, the surface of the modified nano-titanium nitride becomes hydrophilic, forming a hydrophilic-hydrophobic coexisting structure. Therefore, the hydrophilicity of the modified nano-titanium nitride and the super-hydrophobicity of the modified nano-silicene form a complementary structure in the coating. The surface of the coating is first provided with hydrophobic protection by the modified nano-silicene, reducing the penetration of water droplets. At the same time, the micro-crack area inside the coating is accelerated by the hydrophilic hygroscopic effect of the modified nano-titanium nitride to accelerate the self-repair reaction, so that the waterproofness of the coating surface and interior is doubly enhanced. In addition, the super-hydrophobicity of the surface of the modified nano-silicene gives the coating self-cleaning properties. Water droplets on the surface of the coating can not only avoid water penetration through the "ball effect", but also carry away pollutants on the surface of the coating, reducing the degradation of waterproof performance due to the accumulation of pollutants, so that the coating can maintain good waterproofness for a long time. When microcracks appear in the polyurea coating, the modified nano-titanium nitride promotes the self-healing reaction through its hydrophilicity and hydration, while the modified nano-silicene prevents water from penetrating the cracks through its superhydrophobicity, keeping the crack area dry and preventing water from penetrating into the repair area, ensuring the smooth progress of the repair reaction and further improving the self-healing efficiency. The synergistic effect of the two gives the coating a strong waterproof ability, especially when it suffers damage from the external environment. The coating can quickly recover and maintain its waterproof performance. In short, in the polyurea coating, modified dicyclohexylamine, modified nano-titanium nitride, and modified nano-silicene work together to synergistically enhance the self-healing and waterproof properties of the polyurea coating. Modified dicyclohexylamine, through its powerful cross-linking and chain extension function, forms a cross-linked structure of polyurea structure (-NH-CO-NH-) and epoxy groups, giving the coating better structural strength and elasticity, while promoting the automatic healing of cracks. Modified nano-titanium nitride fills cracks through a self-healing reaction, enhancing the waterproofness of the coating. Modified nano-silicene, through its superhydrophobicity and self-cleaning properties, further enhances the waterproofness and weather resistance of the coating, allowing the coating to provide more durable and stronger waterproof protection when facing different environmental challenges, extending the service life of the coating, and ultimately improving the practicality and market competitiveness of the polyurea coating.

[0054] The preparation method of the modified nano-silicene comprises:

[0055] S11. Dispersing the nanosilicene in anhydrous ethanol and ultrasonically treating the nanosilicene at a frequency of 40 to 50 kHz at room temperature for 0.5 to 1 hour, followed by vacuum drying at 75 to 85°C for 6 to 8 hours to obtain clean nanosilicene.

[0056] S12. Preheat the cleaned nanosilicene on a hot plate under a nitrogen atmosphere at 105-120°C for 0.5-1 hour. After preheating, place the nanosilicene in a vapor deposition reaction chamber with a controlled airflow rate of 25-40 sccm. Load heptadecafluorodecyltrimethoxysilane into the vapor deposition reactor evaporator at a deposition temperature of 145-155°C. After 1-2 hours of deposition, turn off the heating device and cool to room temperature.

[0057] S13. After the vapor deposition reaction, the modified nano-silicene is removed and washed three times with anhydrous ethanol. The modified nano-silicene is then vacuum dried at a temperature of 65-75°C for 12-15 hours. The modified nano-silicene is then ground into a powder for later use.

[0058] The preparation method of the modified dicyclohexylamine comprises:

[0059] S21. Under nitrogen atmosphere and stirring, dissolve dicyclohexylamine in anhydrous ethanol. Raise the temperature to 50-60°C and stir for 1.5-2 hours. Add epichlorohydrin, ensuring a 1:1 molar ratio of dicyclohexylamine to epichlorohydrin. Continue stirring for 0.5-1 hour, then slowly add 0.1 mol / L sodium hydroxide solution. Allow to react for 4-6 hours to obtain a first mixed solution.

[0060] S22. The first mixed solution is subjected to high-speed centrifugation at a speed of 6000-8000 rpm for 10-15 minutes. The supernatant is subjected to rotary evaporation. The water bath temperature is set to 50-60°C, the system pressure is set to 100-200 mbar, and the rotation speed is set to 80-100 rpm. After recrystallization, modified dicyclohexylamine is obtained, that is, the modified dicyclohexylamine is prepared by introducing epoxy groups on the surface of dicyclohexylamine.

[0061] The preparation method of the modified nano titanium nitride comprises:

[0062] S31. Nano-titanium nitride was dispersed in a 0.1 mol / L hydrochloric acid solution under stirring and ultrasonicated at a frequency of 40 to 50 kHz for 0.5 to 1 hour at room temperature. The resulting solution was then washed with anhydrous ethanol and then vacuum dried at a temperature of 65 to 75°C for 12 to 15 hours to obtain activated nano-titanium nitride.

[0063] S32. The activated nano-titanium nitride was dispersed in anhydrous ethanol and ultrasonically treated, and sodium dodecylbenzenesulfonate was added, and the ultrasonic frequency was set to 40~50 kHz. The second mixed solution was obtained after ultrasonic treatment at room temperature for 0.5~1h.

[0064] S33 acrylic acid was dissolved in purified water, stirred for 0.5 to 1 h, and then potassium persulfate was slowly added. Stirring was continued for 2 to 4 h, and then the pH value was adjusted to 5.5 to 6.0 using phosphate buffer solution to obtain a third mixed solution;

[0065] S34. The third mixed solution was slowly added to the second mixed solution under stirring to react, the reaction temperature was set to 75~85 ℃, the speed was 400~500 rpm, and the mixture was stirred for 4~6h to obtain a fourth mixed solution;

[0066] S35. The fourth mixed solution is subjected to high-speed centrifugation at a speed of 8,000 to 10,000 rpm for 15 to 20 minutes. The separated solid is washed alternately with anhydrous ethanol and purified water three times and then vacuum dried at a drying temperature of 65 to 75°C for 12 to 15 hours to obtain modified nano-titanium nitride, which is ground into a powder for later use.

[0067] The modified nano-titanium nitride is prepared by covalently grafting polyacrylic acid on the surface of nano-titanium nitride, and the particle size of the modified nano-titanium nitride is 120-150 nm and the specific surface area is 50-70 m 2 / g.

[0068] The dispersant is a compound of gamma-aminopropyltriethoxysilane, sodium dodecylbenzenesulfonate and sodium polyacrylate, wherein the weight ratio of gamma-aminopropyltriethoxysilane, sodium dodecylbenzenesulfonate and sodium polyacrylate is (1-0.5): (1-2): (1.5-2).

[0069] The defoaming agent is a compound of polyoxyethylene polyoxypropylene ether and polydimethylsiloxane, and the weight ratio of polyoxyethylene polyoxypropylene ether to polydimethylsiloxane is (1-0.5): (1-1.5).

[0070] The leveling agent is a polyacrylate leveling agent.

[0071] The stabilizer is a compound of dibutyltin dilaurate, ethylenediaminetetraacetic acid and epoxy soybean oil, wherein the weight ratio of dibutyltin dilaurate, ethylenediaminetetraacetic acid and epoxy soybean oil is (1-2): (0.5-1): (0.5-1).

[0072] A method for preparing a polyurea self-repairing waterproof coating, which is applied to the aforementioned polyurea self-repairing waterproof coating, comprises the following steps:

[0073] S41 polyetheramine was added to ethyl acetate under stirring, and diisocyanate and modified dicyclohexylamine were slowly added after stirring for 0.5 to 1h, and the reaction was continued with stirring at room temperature for 2 to 4h to obtain a fifth mixed solution;

[0074] S42. The modified nano-titanium nitride and modified nano-silicene were sequentially added to the fifth mixed solution under stirring, and after stirring for 1 to 2 hours, a dispersant, a defoamer, a leveling agent, a stabilizer was slowly added, and the reaction was continued with stirring at room temperature for 4 to 6 hours to obtain a sixth mixed solution;

[0075] S43. Filter the sixth mixed solution through a 0.5-1 μm filter to obtain a polyurea self-repairing waterproof coating.

[0076] Example 2: This example discloses a polyurea self-repairing waterproof coating, comprising the following raw materials in parts by weight: 25 parts of diisocyanate, 20 parts of polyetheramine, 10 parts of modified dicyclohexylamine, 2 parts of modified nano-titanium nitride, 0.5 parts of dispersant, 0.1 parts of defoaming agent, 0.5 parts of leveling agent, 0.1 parts of stabilizer, and 5 parts of ethyl acetate. The polyurea self-repairing waterproof coating also includes modified nano-silicene, wherein the modified nano-silicene and diisocyanate are in a weight ratio of 5:25. The modified nano-silicene is prepared by vapor deposition of heptafluorodecyltrimethoxysilane on the surface of the nano-silicene. The particle size of the modified nano-silicene is 20-50 nm, and the specific surface area is 80-100 m 2 / g; the preparation method of the modified nano-silicene, modified dicyclohexylamine and modified nano-titanium nitride in this embodiment is consistent with that in Example 1. The preparation method of a polyurea self-repairing waterproof coating in this embodiment is consistent with that in Example 1.

[0077] Example 3: This example discloses a polyurea self-repairing waterproof coating, comprising the following raw materials in parts by weight: 35 parts of diisocyanate, 30 parts of polyetheramine, 15 parts of modified dicyclohexylamine, 5 parts of modified nano-titanium nitride, 2 parts of dispersant, 0.5 parts of defoaming agent, 2 parts of leveling agent, 0.5 parts of stabilizer, and 10 parts of ethyl acetate. The polyurea self-repairing waterproof coating also includes modified nano-silicene, and the modified nano-silicene and diisocyanate are in a weight ratio of 5:35. The modified nano-silicene is prepared by vapor deposition of heptafluorodecyltrimethoxysilane on the surface of the nano-silicene. The particle size of the modified nano-silicene is 20-50 nm, and the specific surface area is 80-100 m 2 / g; the preparation method of the modified nano-silicene, modified dicyclohexylamine and modified nano-titanium nitride in this embodiment is consistent with that in Example 1. The preparation method of a polyurea self-repairing waterproof coating in this embodiment is consistent with that in Example 1.

[0078] Control Group 1: This example differs from Example 1 in that it does not contain modified nano-silicene. This example discloses a polyurea self-healing waterproof coating comprising the following raw materials in parts by weight: 30 parts diisocyanate, 25 parts polyetheramine, 12.5 parts modified dicyclohexylamine, 3.5 parts modified nano-titanium nitride, 1.25 parts dispersant, 0.3 parts defoamer, 1.25 parts leveling agent, 0.3 parts stabilizer, and 12.5 parts ethyl acetate. The preparation methods for the modified dicyclohexylamine and modified nano-titanium nitride in this example are the same as those in Example 1. The preparation method for a polyurea self-healing waterproof coating in this example is the same as that in Example 1.

[0079] Control group 2: The difference between this embodiment and embodiment 1 is that modified dicyclohexylamine is not contained. This embodiment discloses a polyurea self-repairing waterproof coating, comprising the following raw materials in parts by weight: 30 parts of diisocyanate, 25 parts of polyetheramine, 3.5 parts of modified nano-titanium nitride, 1.25 parts of dispersant, 0.3 parts of defoaming agent, 1.25 parts of leveling agent, 0.3 parts of stabilizer, and 12.5 parts of ethyl acetate. The polyurea self-repairing waterproof coating also includes modified nano-silicene, and the modified nano-silicene and diisocyanate are in a weight ratio of 5:30. The modified nano-silicene is prepared by vapor deposition of heptafluorodecyltrimethoxysilane on the surface of the nano-silicene. The particle size of the modified nano-silicene is 20~50 nm, and the specific surface area is 80~100 m 2 / g; the preparation method of the modified nano-silicene and modified nano-titanium nitride in this embodiment is consistent with that in Example 1. The preparation method of a polyurea self-repairing waterproof coating in this embodiment is consistent with that in Example 1.

[0080] Control group 3: The difference between this embodiment and embodiment 1 is that modified nano titanium nitride is not contained. This embodiment discloses a polyurea self-repairing waterproof coating, comprising the following raw materials in parts by weight: 30 parts of diisocyanate, 25 parts of polyetheramine, 12.5 parts of modified dicyclohexylamine, 1.25 parts of dispersant, 0.3 parts of defoamer, 1.25 parts of leveling agent, 0.3 parts of stabilizer, and 12.5 parts of ethyl acetate. The polyurea self-repairing waterproof coating also includes modified nanosilicene, and the modified nanosilicene and diisocyanate are in a weight ratio of 5:30. The modified nanosilicene is prepared by vapor deposition of heptafluorodecyltrimethoxysilane on the surface of the nanosilicene. The particle size of the modified nanosilicene is 20~50 nm, and the specific surface area is 80~100 m 2 / g; the preparation method of the modified nano-silicene and modified dicyclohexylamine in this embodiment is consistent with that in Example 1. The preparation method of a polyurea self-repairing waterproof coating in this embodiment is consistent with that in Example 1.

[0081] Effect evaluation: Performance measurement of polyurea self-healing waterproof coating: (1) Self-healing performance experiment: The polyurea coating obtained from each experimental group was evenly coated on the surface of the glass substrate. After drying and curing, the coating surface was rubbed with a 15N scraping component to scratch the entire coating surface. Under the environmental conditions of an ambient temperature of 30°C and an air relative humidity of 50%, the self-healing of the coating was observed and the self-healing efficiency was calculated by the coating damage area. Three parallel tests were set up for each experimental group, and the experimental results were averaged. (2) Waterproofness test: The water contact angle θ of the coating surface was measured using a JC2000C dynamic contact angle meter. Three parallel tests were set up for each experimental group, and the experimental results were averaged.

[0082]

[0083] Table 1 shows the statistical results of the performance measurement of the polyurea self-repairing waterproof coatings obtained in each experimental group. It can be seen from Table 1 that there are obvious differences in the self-repairing and waterproof properties of the polyurea coatings prepared in each experimental group. By comparing the polyurea coatings prepared in Examples 1 to 3 with those prepared in Control Groups 1 to 3, it can be found that, overall, the self-repairing and waterproof properties of the polyurea coatings prepared in Examples 1 to 3 are better, and the polyurea self-repairing waterproof coating prepared in Example 1 exhibits excellent self-repairing and waterproof properties, with a maximum self-repairing efficiency of 99.5%. The high self-repairing efficiency means that the coating can quickly and effectively repair the damaged part, reducing the negative impact of the damage on the overall performance of the coating. The water contact angle is also the highest at 118°. The higher water contact angle means that the coating surface is very hydrophobic, water droplets are not easy to adhere to the coating, water will quickly roll off or be repelled, and the waterproof performance is strong. By comparing Example 1 with Control Groups 1 to 3, it can be found that when modified dicyclohexylamine, modified nano-titanium nitride and modified nano-silicene are added simultaneously to prepare the polyurea coating, the self-healing performance and waterproof performance of the polyurea coating can be significantly improved, thereby ensuring the integrity of the coating.

[0084]

[0085] Table 2 shows the comparative results of waterproof performance test of the polyurea waterproof coating prepared in Example 1 and the polyurea coating sold on the market. It can be seen that the polyurea self-repairing waterproof coating prepared in Example 1 exhibits excellent waterproof performance.

[0086] After the above limited experiments, the application effect of a polyurea self-healing waterproof coating in Example 1 of the present invention is significant. By optimizing the material formula of the polyurea self-healing waterproof coating, modified dicyclohexylamine, modified nano-titanium nitride and modified nano-silicene are added simultaneously during the production process, and combined with modern nanotechnology, the self-healing performance and waterproof performance of the polyurea coating are significantly improved. The modified dicyclohexylamine promotes the formation of a polyurea composite cross-linked structure, providing a stable carrier support for the modified nano-titanium nitride and modified nano-silicene. The hydrophilicity of the modified nano-titanium nitride and the super-hydrophobicity of the modified nano-silicene form a complementary structure, which not only provides hydrophobic protection, but also accelerates the self-healing reaction through hydrophilic moisture absorption, so that the waterproofness of the coating surface and interior is doubly enhanced, thereby maintaining the integrity of the repair area, so that the coating can provide more lasting and stronger waterproof protection when facing different environmental challenges, extending the service life of the coating, and ultimately improving the practicality and market competitiveness of the polyurea coating.

[0087] Finally, it should be noted that although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A polyurea self-repairing waterproof coating, characterized in that: The invention comprises the following raw materials in parts by weight: 25-35 parts of diisocyanate, 20-30 parts of polyetheramine, 10-15 parts of modified dicyclohexylamine, 2-5 parts of modified nano titanium nitride, 0.5-2 parts of dispersant, 0.1-0.5 parts of defoamer, 0.5-2 parts of leveling agent, 0.1-0.5 parts of stabilizer, and 5-10 parts of ethyl acetate; the polyurea self-repairing waterproof coating also comprises: modified nano-silicene; the modified nano-silicene and diisocyanate are in a weight ratio of 5:(25-35); the modified nano-silicene is prepared by vapor deposition of heptafluorodecyltrimethoxysilane on the surface of the nano-silicene, and the particle size of the modified nano-silicene is 20-50 nm and the specific surface area is 80-100 m 2 / g; the preparation method of modified dicyclohexylamine comprises: S21. Under nitrogen protection and stirring, dissolving dicyclohexylamine in anhydrous ethanol, raising the temperature to 50-60°C, stirring for 1.5-2 hours, then adding epichlorohydrin to ensure a molar ratio of dicyclohexylamine to epichlorohydrin of 1:1, continuing stirring for 0.5-1 hour, then slowly adding 0.1 mol / L sodium hydroxide solution, and reacting for 4-6 hours to obtain a first mixed solution; S22. subjecting the first mixed solution to high-speed centrifugation at a speed of 6000-8000 rpm for 10-15 minutes, removing the supernatant and subjecting it to rotary evaporation in a water bath at a temperature of 50-60°C, a system pressure of 100-200 mbar, and a speed of 80-100 rpm. After recrystallization, the modified dicyclohexylamine is obtained, i.e., the modified dicyclohexylamine is prepared by introducing epoxy groups onto the surface of the dicyclohexylamine; the preparation method of modified nano-titanium nitride comprises: S31. Under stirring, disperse nano-titanium nitride in 0.1 mol / L hydrochloric acid solution and perform ultrasonic treatment, set the ultrasonic frequency to 40~50 kHz, perform ultrasonic treatment at room temperature for 0.5~1 hour, then wash with anhydrous ethanol, and then perform vacuum drying, set the drying temperature to 65~75℃, and dry for 12~15 hours to obtain activated nano-titanium nitride; S32. Disperse the activated nano-titanium nitride in anhydrous ethanol and perform ultrasonic treatment, add sodium dodecylbenzenesulfonate, set the ultrasonic frequency to 40~50kHz, and perform ultrasonic treatment at room temperature for 0.5~1 hour to obtain a second mixed solution; S33. Dissolve acrylic acid in purified water, stir for 0.5~1 hour, then slowly add potassium persulfate, continue stirring for 2~4 hours, and adjust the pH value to 5.5~6.0 with phosphate buffer solution to obtain a third mixed solution; S34. Slowly add the third mixed solution to the second mixed solution under stirring to react, set the reaction temperature to 75~85℃, and the rotation speed to 400~500℃. rpm, and stirred for 4 to 6 hours to obtain a fourth mixed solution; S35. The fourth mixed solution is subjected to high-speed centrifugation at a speed of 8000 to 10000 rpm for 15 to 20 minutes. The separated solid is washed alternately with anhydrous ethanol and purified water three times, and then vacuum dried at a drying temperature of 65 to 75°C. After drying for 12 to 15 hours, the modified nano-titanium nitride is obtained and ground into powder for later use.

2. The polyurea self-repairing waterproof coating according to claim 1, characterized in that: The modified nano-silicene preparation method comprises: S11. Dispersing the nano-silicene in anhydrous ethanol and subjecting it to ultrasonic treatment at a frequency of 40 to 50 kHz at room temperature for 0.5 to 1 hour, followed by vacuum drying at a temperature of 75 to 85°C for 6 to 8 hours to obtain clean nano-silicene; S12. Preheating the clean nano-silicene on a hot plate under a nitrogen atmosphere at a temperature of 105 to 120°C for 0.5 to 1 hour, followed by placement in a vapor deposition reaction chamber at a controlled airflow rate of 25 to 40 sccm, charging heptafluorodecyltrimethoxysilane into the evaporator of the vapor deposition reactor, setting the deposition temperature to 145 to 155°C, allowing the deposition reaction to continue for 1 to 2 hours, turning off the heating device, and cooling to room temperature; S13. The modified nano-silicene after the vapor deposition reaction is taken out and washed with anhydrous ethanol three times, and then vacuum dried at a drying temperature of 65-75°C. After drying for 12-15 hours, the modified nano-silicene is obtained and ground into powder for later use.

3. The polyurea self-repairing waterproof coating according to claim 1, characterized in that: The modified nano-titanium nitride is prepared by covalently grafting polyacrylic acid on the surface of nano-titanium nitride, and the particle size of the modified nano-titanium nitride is 120-150 nm and the specific surface area is 50-70 m 2 / g.

4. The polyurea self-repairing waterproof coating according to claim 1, characterized in that: The dispersant is a compound of gamma-aminopropyltriethoxysilane, sodium dodecylbenzenesulfonate and sodium polyacrylate, wherein the weight ratio of gamma-aminopropyltriethoxysilane, sodium dodecylbenzenesulfonate and sodium polyacrylate is (1-0.5): (1-2): (1.5-2).

5. The polyurea self-repairing waterproof coating according to claim 1, characterized in that: The defoaming agent is a compound of polyoxyethylene polyoxypropylene ether and polydimethylsiloxane, and the weight ratio of polyoxyethylene polyoxypropylene ether to polydimethylsiloxane is (1-0.5): (1-1.5).

6. The polyurea self-repairing waterproof coating according to claim 1, characterized in that: The leveling agent is a polyacrylate leveling agent.

7. The polyurea self-repairing waterproof coating according to claim 1, characterized in that: The stabilizer is a compound of dibutyltin dilaurate, ethylenediaminetetraacetic acid and epoxy soybean oil, wherein the weight ratio of dibutyltin dilaurate, ethylenediaminetetraacetic acid and epoxy soybean oil is (1-2): (0.5-1): (0.5-1).

8. A method for preparing a polyurea self-repairing waterproof coating, which is used to prepare a polyurea self-repairing waterproof coating as claimed in any one of claims 1 to 7, characterized in that: The method comprises the following steps: S41. adding polyetheramine to ethyl acetate under stirring, stirring for 0.5 to 1 hour, slowly adding diisocyanate and modified dicyclohexylamine, and continuing stirring and reacting at room temperature for 2 to 4 hours to obtain a fifth mixed solution; S42. sequentially adding modified nano-titanium nitride and modified nano-silicene to the fifth mixed solution under stirring, stirring for 1 to 2 hours, slowly adding a dispersant, a defoaming agent, a leveling agent, and a stabilizer, and continuing stirring and reacting at room temperature for 4 to 6 hours to obtain a sixth mixed solution; S43. filtering the sixth mixed solution through a 0.5 to 1 μm filter screen to obtain a polyurea self-repairing waterproof coating.

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