Polyurea self-repairing waterproof coating and preparation method thereof

Abstract

The invention relates to the technical field of self-repairing waterproof coatings, in particular to a polyurea self-repairing waterproof coating and a preparation method thereof.The polyurea self-repairing waterproof coating is prepared from diisocyanate, polyether amine, modified dicyclohexylamine, modified nano titanium nitride, modified nano silylene, a dispersing agent, a defoaming agent, a flatting agent, a stabilizer and ethyl acetate. The modified dicyclohexylamine, the modified nano titanium nitride and the modified nano silylene synergistically improve the self-repairing performance and the waterproof performance of the polyurea coating, the modified dicyclohexylamine promotes formation of a polyurea composite cross-linked structure, and a carrier supporting effect is provided for the modified nano titanium nitride and the modified nano silylene; the hydrophilicity of the modified nano titanium nitride and the super-hydrophobicity of the modified nano silylene form a complementary structure, so that hydrophobic protection is provided, and a self-repairing reaction is accelerated through a hydrophilic moisture absorption effect, so that the water repellency of the surface and the interior of the coating is doubly enhanced, and the integrity of a repaired area is kept.

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 is a type of polymer material generated by the reaction of isocyanate and amine. It has excellent mechanical properties, corrosion resistance and wear resistance. Due to its excellent physical properties, excellent waterproof properties and fast curing characteristics, it has been widely used in construction, roads, tunnels, water conservancy, ships and other fields. In actual production applications, polyurea waterproof coatings can effectively prevent water penetration, protect the substrate, and show excellent water resistance and aging resistance in harsh environments. However, traditional polyurea coatings will inevitably have microcracks or damage caused by external pressure, impact, temperature changes and other reasons during use. Once cracks appear in the coating, the waterproof function will be significantly affected, resulting in damage to the substrate. In addition, under harsh environmental conditions such as high temperature, low temperature, and humidity changes, the durability and waterproof function of the coating are also particularly important. Improving the weather resistance, crack resistance and self-repairing ability of the coating can greatly extend the service life of the coating, while improving its waterproof performance, reducing the need for frequent repairs and replacements, and reducing long-term maintenance costs. This is of great significance for the protection of important projects such as buildings and infrastructure, especially in environments such as underground buildings and bridges that require long-term and stable waterproof effects. Therefore, it is very meaningful to develop a polyurea waterproof coating with self-healing 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 issues to be resolved 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 modern nanotechnology to significantly improve the self-repairing performance and waterproof performance of the polyurea coating, ensure that the coating can respond quickly and restore the waterproof performance when damaged, ensure the integrity of the coating, and ultimately improve the practicality and market competitiveness of the polyurea coating.

[0004] (2) Technical solution To achieve the above object, 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 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 includes: 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-depositing heptadecafluorodecyltrimethoxysilane 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 comprises: S11. The nano-silicene is dispersed in anhydrous ethanol and subjected to ultrasonic treatment at a frequency of 40 to 50 kHz. The ultrasonic treatment is performed at room temperature for 0.5 to 1 hour, and then vacuum dried at a temperature of 75 to 85°C. After drying for 6 to 8 hours, the washed nano-silicene is obtained. S12. Place the washed nano-silicene on a heating plate for preheating in a nitrogen atmosphere at a temperature of 105-120°C. After preheating for 0.5-1h, place it in a vapor deposition reaction chamber, control the gas flow rate to 25-40 sccm, load heptadecafluorodecyltrimethoxysilane into the evaporator of the vapor deposition reactor, set the deposition temperature to 145-155°C, turn off the heating device after the deposition reaction for 1-2h, and cool to room temperature; S13. After the vapor deposition reaction is completed, the modified nano-silicene is taken out and washed with anhydrous ethanol for 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.

[0005] Furthermore, the preparation method of the modified dicyclohexylamine comprises: S21. Dissolve dicyclohexylamine in anhydrous ethanol under nitrogen protection and stirring, and heat to 50-60°C. After stirring for 1.5-2 hours, add epichlorohydrin to ensure that the molar ratio of dicyclohexylamine to epichlorohydrin is 1:1. Continue stirring for 0.5-1 hour, then slowly add 0.1 mol / L sodium hydroxide solution, and react for 4-6 hours to obtain a first mixed solution; S22. The first mixed solution is subjected to high-speed centrifugation at a speed of 6000-8000 rpm for 10-15 min, 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, the speed is set to 80-100 rpm, and the modified dicyclohexylamine is obtained after recrystallization, that is, the modified dicyclohexylamine is prepared by introducing epoxy groups on the surface of dicyclohexylamine.

[0006] Furthermore, the preparation method of the modified nano titanium nitride comprises: S31. Dispersing nano-titanium nitride in a 0.1 mol / L hydrochloric acid solution under stirring and performing ultrasonic treatment, setting the ultrasonic frequency to 40-50 kHz, performing ultrasonic treatment at room temperature for 0.5-1 h, then washing with anhydrous ethanol, and then performing vacuum drying, setting the drying temperature to 65-75°C, and drying for 12-15 h to obtain activated nano-titanium nitride; S32. The activated nano-titanium nitride was dispersed in anhydrous ethanol and subjected to ultrasonic treatment, and sodium dodecylbenzene sulfonate was added, and the ultrasonic frequency was set to 40 to 50 kHz, and the second mixed solution was obtained after ultrasonic treatment at room temperature for 0.5 to 1 h; S33. Dissolve acrylic acid in purified water, stir for 0.5 to 1 h, then slowly add potassium persulfate, continue stirring for 2 to 4 h, and then use phosphate buffered saline to adjust the pH value to 5.5 to 6.0 to obtain a third mixed solution; S34. The third mixed solution was slowly added to the second mixed solution under stirring to react, the reaction temperature was set to 75 to 85 ° C, the speed was 400 to 500 rpm, and the stirring was performed for 4 to 6 hours to obtain a fourth mixed solution; S35. The fourth mixed solution is subjected to high-speed centrifugation at a rotation speed of 8000-10000 rpm for 15-20 min. The separated solid is washed alternately with anhydrous ethanol and purified water for 3 times and then vacuum dried at a drying temperature of 65-75°C. After drying for 12-15 h, the modified nano-titanium nitride is obtained and ground into powder for later use.

[0007] 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.

[0008] 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).

[0009] 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).

[0010] Furthermore, the leveling agent is a polyacrylate leveling agent.

[0011] 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).

[0012] 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 polyurea self-repairing waterproof coating, and comprises the following steps: S41. The polyetheramine was added to ethyl acetate under stirring, and diisocyanate and modified dicyclohexylamine were slowly added after stirring for 0.5 to 1 h, and the reaction was continued with stirring at room temperature for 2 to 4 h to obtain a fifth mixed solution; S42. The modified nano-titanium nitride and the modified nano-silicene were sequentially added to the fifth mixed solution under stirring, and the dispersant, defoamer, leveling agent and stabilizer were slowly added after stirring for 1 to 2 hours, and the reaction was continued at room temperature with stirring for 4 to 6 hours to obtain a sixth mixed solution; S43. The sixth mixed solution is filtered through a 0.5-1 μm filter to obtain a polyurea self-repairing waterproof coating.

[0013] The mechanism of action of the above raw material components is as follows: In the polyurea self-healing waterproof coating, the -NCO group of diisocyanate first reacts with the amine group (-NH 2 ) undergoes addition polymerization to form a basic cross-linked network structure, providing the coating with basic strength and waterproof properties. 2 -O-CH-) to prepare modified dicyclohexylamine, which is a chain extender that can not only improve the reactivity of isocyanate, but also the surface amino groups (-NH 2 ) can also react with diisocyanates to form long-chain polyurea structures. By increasing the length of the molecular chain, the strength, toughness and weather resistance of polyurea coatings are further improved. At the same time, the epoxy groups (-CH 2 -O-CH-) further binds to the amine groups (-NH 2 ) undergoes a ring-opening reaction to form an epoxy network to increase the crosslinking degree of the polyurea system, 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 react with the amine groups (-NH 2 ) to further react and undergo self-repair crosslinking, while modifying the epoxy groups (-CH 2 -O-CH-) by reacting with free -NH 2 / -NCO group undergoes ring-opening reaction, which heals the microcracks of the coating. The ring structure of the epoxy group also further improves the weather resistance of the coating and prevents crack expansion. The polyurea cross-linking structure provides a stable carrier support for the modified nano titanium nitride and modified nano silicene, so that both can 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. The 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 segment, which will interact with the hydrophilic groups such as amino or hydroxyl 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 more dense and 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, which 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 depositing heptadecafluorodecyltrimethoxysilane on the surface of nanosilicene. The vapor deposition method enables the 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, allowing water droplets to 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 modified by hydrophilic polyacrylic acid grafting, a hydrophilic-hydrophobic structure is formed. Therefore, the hydrophilicity of modified nano-titanium nitride and the super-hydrophobicity of modified nano-silicene form a complementary structure in the coating. The surface of the coating is first protected by hydrophobicity by modified nano-silicene to reduce water drop penetration. At the same time, the micro-crack area inside the coating accelerates the self-repair reaction through the hydrophilic hygroscopic effect of modified nano-titanium nitride, so that the waterproofness of the surface and interior of the coating is doubly enhanced. In addition, the super-hydrophobicity of the surface of modified nano-silicene makes the coating have self-cleaning properties. Water droplets on the surface of the coating can not only avoid water penetration through the "ball effect", but also take away pollutants on the surface of the coating. 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 moisture from penetrating into the cracks through its superhydrophobicity, keeping the crack area dry and further improving the self-healing efficiency. The synergistic effect of the two makes the coating have strong waterproof ability, especially when it is damaged by the external environment, the coating can quickly recover and maintain its waterproof performance.In summary, in polyurea coatings, modified dicyclohexylamine, modified nano-titanium nitride and modified nano-silicene work together to synergistically improve the self-healing and waterproof properties of polyurea coatings. Modified dicyclohexylamine forms a cross-linked structure of polyurea structure (-NH-CO-NH-) and epoxy group through its powerful cross-linking and chain extension function, which makes the coating have better structural strength and elasticity, and promotes automatic healing of cracks; modified nano-titanium nitride fills cracks through self-healing reaction and enhances the waterproofness of the coating, and modified nano-silicene further enhances the waterproofness and weather resistance of the coating through its super hydrophobicity and self-cleaning properties, so that the coating can provide more durable and stronger waterproof protection when facing different environmental challenges, extend the service life of the coating, and ultimately improve the practicality and market competitiveness of polyurea coatings.

[0014] The dispersant can improve the dispersibility of nanoparticles, prevent precipitation and agglomeration, and improve 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 γ-aminopropyltriethoxysilane can form a covalent bond with the modified nano titanium nitride and the modified nano silicene, thereby improving the dispersibility of the modified nano titanium nitride and the modified nano silicene in the coating. At the same time, the amino group (-NH 2 ) can form hydrogen bonds with polyurea groups (-NH-CO-NH-), further improving the water resistance and chemical bonding strength of the coating; sodium dodecylbenzene sulfonate is an anionic surfactant that can reduce surface tension and prevent the 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 the sedimentation of components.

[0015] The main function of the defoamer is to prevent the generation of bubbles in the coating during the construction process and improve the surface smoothness and aesthetics of the coating. It mainly reduces the surface tension of the liquid, thereby destroying the stability of the foam and preventing the formation and accumulation of foam. The defoamer of the present invention is a compound of polyoxyethylene polyoxypropylene ether and polydimethylsiloxane. The polyoxyethylene polyoxypropylene ether reduces the interfacial tension, destroys the stability of the bubbles, and prevents the formation of foam. Polydimethylsiloxane is a low surface energy defoamer that can quickly break the surface bubbles and improve the smoothness and uniformity of the coating.

[0016] The leveling agent reduces the surface tension of the coating, improves the fluidity and spreadability of the coating, and enables the coating to be evenly distributed after construction. The leveling agent of the present invention is a polyacrylate leveling agent, which reduces the surface tension, improves the fluidity of the coating, improves the surface flatness and glossiness of the coating, and reduces the sagging and orange peel phenomenon of the coating.

[0017] The stabilizer improves the stability and durability of the coating by inhibiting the oxidation, hydrolysis and photodegradation reactions of the coating, prevents the coating from deteriorating and failing during storage and use, and prolongs the storage and service life of the coating. The stabilizer of the present invention is a compound of dibutyltin dilaurate, ethylenediaminetetraacetic acid and epoxy soybean oil. Dibutyltin dilaurate is a catalyst that can promote the addition polymerization reaction of diisocyanate and polyetheramine, increase the curing speed of the coating, and provide thermal stability to prevent the reaction from getting out of control during long-term storage; ethylenediaminetetraacetic acid can chelate metal ions to prevent the catalyst from failing and ensure the long-term stability of the coating; epoxy soybean oil is a plasticizer that can improve the flexibility of the coating and prevent cracking, and its epoxy group (-CH 2 -O-CH-) can also react with amine groups (-NH 2 ) reaction, further improving the weather resistance and self-healing ability of the coating.

[0018] Ethyl acetate is a commonly used organic solvent that can dissolve various organic components in the paint and evaporate quickly during the film-forming process, thereby adjusting the viscosity and fluidity of the paint and making the paint easy to apply and dry.

[0019] (3) Beneficial effects Compared with the prior art, the present invention has the following beneficial effects: Modified dicyclohexylamine, modified nano-titanium nitride and modified nano-silicene synergistically improve the self-healing and waterproof properties of polyurea coatings. Modified dicyclohexylamine forms a composite cross-linked structure of polyurea structure and epoxy group through its powerful cross-linking and chain extension function, which promotes automatic healing of cracks and effectively prevents water penetration. The polyurea composite cross-linked structure provides a stable carrier support for the modified nano-titanium nitride and the modified nano-silicene, so that the two can be evenly dispersed in the polyurea system; 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; The modified nano-silicene forms a uniform hydrophobic protective film, which makes water droplets form "spherical" water droplets with a large contact angle on the surface, improves the waterproofness of the coating, and removes pollutants on the coating surface through the "ball effect"; The hydrophilicity of modified nano-titanium nitride and the super-hydrophobicity of modified nano-silicene form a complementary structure in the coating. The surface of the coating is firstly protected by hydrophobicity provided by modified nano-silicene to reduce the penetration of water droplets. The micro-crack area inside the coating is accelerated to self-repair through the hydrophilic and hygroscopic effect of modified nano-titanium nitride, so that the waterproofness of the coating surface and inside is doubly enhanced. The modified nano-titanium nitride promotes the self-healing reaction through its hydrophilicity and hydration, while the modified nano-silicene prevents water from penetrating into the cracks through its superhydrophobicity, keeps the crack area dry, improves the self-healing efficiency, and maintains the integrity of the repair area. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a SEM image of modified nano-titanium nitride in Example 1 of the present invention; Figure 2 This is the SEM image of the modified nano-silicene in Example 1 of the present invention. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] The experimental equipment and preparations of the embodiments described below are as follows: electronic balance (Sartorius, Germany), electric constant temperature water bath (Jiangsu Kedao), magnetic stirrer (Shanghai Meiyingpu), ultrasonic instrument (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 Neumute), 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.

[0023] Example 1: This example discloses a polyurea self-healing 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 defoamer, 1.25 parts of leveling agent, 0.3 parts of stabilizer, and 12.5 parts of ethyl acetate. The polyurea self-healing waterproof coating also includes modified nano-silicene, wherein the weight ratio of the modified nano-silicene to the diisocyanate is 5:30, and the modified nano-silicene is prepared by vapor deposition of heptadecafluorodecyltrimethoxysilane 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.

[0024] In the polyurea self-healing waterproof coating, the -NCO group of diisocyanate first reacts with the amine group (-NH 2) undergoes addition polymerization 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. 2 -O-CH-) to prepare modified dicyclohexylamine, which is a chain extender that plays the role of extending the molecular chain, which can not only improve the reactivity of isocyanate, but also the surface amino group (-NH 2 ) can also react with diisocyanates to form long-chain polyurea structures. By increasing the length of the molecular chain, the strength, toughness and weather resistance of polyurea coatings are further improved. At the same time, the epoxy groups (-CH 2 -O-CH-) and the amine group (-NH 2 ) undergoes a ring-opening reaction to form an epoxy network, thereby generating a new cross-linking structure and increasing the cross-linking degree of the polyurea system. The high-strength polyurea cross-linking structure can effectively isolate moisture, prevent moisture penetration, and avoid moisture corrosion and damage to the underlying material of the coating, 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 group in the polyurea system will react with the amine group (-NH 2 ) to further react and undergo self-repair crosslinking, while modifying the epoxy groups (-CH 2 -O-CH-) by reacting with free -NH 2 The / -NCO group undergoes a ring-opening reaction, which heals the microcracks in the coating. The ring structure of the epoxy group also further improves the weather resistance of the coating and prevents crack expansion. The polyurea cross-linked structure provides a stable carrier support for the modified nano-titanium nitride and modified nano-silicene, allowing both 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 1 The SEM image of modified nano-titanium nitride shows that the modified nano-titanium nitride has a very obvious dense structure. The grafted polyacrylic acid is a hydrophilic segment, which will react with the amino group (-NH 2) or hydroxyl (-OH) and other hydrophilic groups to further enhance the interfacial bonding force between the modified nano titanium nitride and the polyurea cross-linked structure, so that the modified nano titanium nitride and the polyurea cross-linked structure can be better combined to form a more dense and 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 penetration path of water through the coating, and prevent water penetration. Nano silicene is a new type of two-dimensional material with a high specific surface area and excellent chemical stability. Modified nano silicene is prepared by vapor deposition of heptadecafluorodecyltrimethoxysilane on the surface of nano silicene. Figure 2From the SEM image of modified nano-silicene, we can see that the modified nano-silicene is spherical in shape. 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 modified by hydrophilic polyacrylic acid grafting, the surface of the modified nano-titanium nitride shows hydrophilicity, 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 to reduce 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 surface and the inside of the coating is doubly enhanced. In addition, the super-hydrophobicity of the surface of the modified nano-silicene makes the coating have self-cleaning properties. Water droplets on the surface of the coating can not only avoid water penetration through the "ball effect", but also take 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-repair reaction through its hydrophilicity and hydration, while the modified nano-silicene prevents water from penetrating into the cracks through its super-hydrophobicity, keeps the crack area dry, and prevents water from penetrating into the repair area, ensuring that the repair reaction proceeds smoothly, further improving the self-repair efficiency. The synergistic effect of the two makes the coating have a strong waterproof ability, especially when it is damaged by 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 improve the self-repair and waterproof properties of the polyurea coating. Modified dicyclohexylamine forms a cross-linked structure of polyurea structure (-NH-CO-NH-) and epoxy group through its powerful cross-linking and chain extension function, which makes the coating have better structural strength and elasticity, and promotes automatic healing of cracks; modified nano-titanium nitride fills cracks through self-healing reaction and enhances the waterproofness of the coating; modified nano-silicene further enhances the waterproofness and weather resistance of the coating through its super hydrophobicity and self-cleaning properties, so that the coating can provide more durable and stronger waterproof protection when facing different environmental challenges, extend the service life of the coating, and ultimately improve the practicality and market competitiveness of polyurea coatings.

[0025] The preparation method of the modified nano-silicene comprises: S11. The nano-silicene is dispersed in anhydrous ethanol and subjected to ultrasonic treatment at a frequency of 40 to 50 kHz. The ultrasonic treatment is performed at room temperature for 0.5 to 1 hour, and then vacuum dried at a temperature of 75 to 85°C. After drying for 6 to 8 hours, the washed nano-silicene is obtained. S12. Place the washed nano-silicene on a heating plate for preheating in a nitrogen atmosphere at a temperature of 105-120°C. After preheating for 0.5-1h, place it in a vapor deposition reaction chamber, control the gas flow rate to 25-40 sccm, load heptadecafluorodecyltrimethoxysilane into the evaporator of the vapor deposition reactor, set the deposition temperature to 145-155°C, turn off the heating device after the deposition reaction for 1-2h, and cool to room temperature; S13. After the vapor deposition reaction is completed, the modified nano-silicene is taken out and washed with anhydrous ethanol for 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.

[0026] The preparation method of the modified dicyclohexylamine comprises: S21. Dissolve dicyclohexylamine in anhydrous ethanol under nitrogen protection and stirring, and heat to 50-60°C. After stirring for 1.5-2 hours, add epichlorohydrin to ensure that the molar ratio of dicyclohexylamine to epichlorohydrin is 1:1. Continue stirring for 0.5-1 hour, then slowly add 0.1 mol / L sodium hydroxide solution, and react for 4-6 hours to obtain a first mixed solution; S22. The first mixed solution is subjected to high-speed centrifugation at a speed of 6000-8000 rpm for 10-15 min, 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, the speed is set to 80-100 rpm, and the modified dicyclohexylamine is obtained after recrystallization, that is, the modified dicyclohexylamine is prepared by introducing epoxy groups on the surface of dicyclohexylamine.

[0027] The preparation method of the modified nano titanium nitride comprises: S31. Dispersing nano-titanium nitride in a 0.1 mol / L hydrochloric acid solution under stirring and performing ultrasonic treatment, setting the ultrasonic frequency to 40-50 kHz, performing ultrasonic treatment at room temperature for 0.5-1 h, then washing with anhydrous ethanol, and then performing vacuum drying, setting the drying temperature to 65-75°C, and drying for 12-15 h to obtain activated nano-titanium nitride; S32. The activated nano-titanium nitride was dispersed in anhydrous ethanol and subjected to ultrasonic treatment, and sodium dodecylbenzene sulfonate was added, and the ultrasonic frequency was set to 40 to 50 kHz, and the second mixed solution was obtained after ultrasonic treatment at room temperature for 0.5 to 1 h; S33. Dissolve acrylic acid in purified water, stir for 0.5 to 1 h, then slowly add potassium persulfate, continue stirring for 2 to 4 h, and then use phosphate buffered saline to adjust the pH value to 5.5 to 6.0 to obtain a third mixed solution; S34. The third mixed solution was slowly added to the second mixed solution under stirring to react, the reaction temperature was set to 75 to 85 ° C, the speed was 400 to 500 rpm, and the stirring was performed for 4 to 6 hours to obtain a fourth mixed solution; S35. The fourth mixed solution is subjected to high-speed centrifugation at a rotation speed of 8000-10000 rpm for 15-20 min. The separated solid is washed alternately with anhydrous ethanol and purified water for 3 times and then vacuum dried at a drying temperature of 65-75°C. After drying for 12-15 h, the modified nano-titanium nitride is obtained and ground into powder for later use.

[0028] 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.

[0029] The dispersant is a compound of γ-aminopropyltriethoxysilane, sodium dodecylbenzene sulfonate and sodium polyacrylate, wherein the weight ratio of γ-aminopropyltriethoxysilane, sodium dodecylbenzene sulfonate and sodium polyacrylate is (1-0.5): (1-2): (1.5-2).

[0030] 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).

[0031] The leveling agent is a polyacrylate leveling agent.

[0032] The stabilizer is a compound of dibutyltin dilaurate, ethylenediaminetetraacetic acid and epoxidized soybean oil, wherein the weight ratio of dibutyltin dilaurate, ethylenediaminetetraacetic acid and epoxidized soybean oil is (1-2): (0.5-1): (0.5-1).

[0033] A method for preparing a polyurea self-repairing waterproof coating, which is applied to the polyurea self-repairing waterproof coating, comprises the following steps: S41. The polyetheramine was added to ethyl acetate under stirring, and diisocyanate and modified dicyclohexylamine were slowly added after stirring for 0.5 to 1 h, and the reaction was continued with stirring at room temperature for 2 to 4 h to obtain a fifth mixed solution; S42. The modified nano-titanium nitride and the modified nano-silicene were sequentially added to the fifth mixed solution under stirring, and the dispersant, defoamer, leveling agent and stabilizer were slowly added after stirring for 1 to 2 hours, and the reaction was continued at room temperature with stirring for 4 to 6 hours to obtain a sixth mixed solution; S43. The sixth mixed solution is filtered through a 0.5-1 μm filter to obtain a polyurea self-repairing waterproof coating.

[0034] Example 2: This example discloses a polyurea self-healing 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 defoamer, 0.5 parts of leveling agent, 0.1 parts of stabilizer, and 5 parts of ethyl acetate. The polyurea self-healing waterproof coating also includes modified nano silicene, wherein the weight ratio of the modified nano silicene to the diisocyanate is 5:25, and the modified nano silicene is prepared by vapor deposition of heptadecafluorodecyltrimethoxysilane 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 methods of the modified nano-silicene, modified dicyclohexylamine and modified nano-titanium nitride in this embodiment are consistent with those in Example 1. The preparation method of a polyurea self-repairing waterproof coating in this embodiment is consistent with that in Example 1.

[0035] Example 3: This example discloses a polyurea self-healing 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 defoamer, 2 parts of leveling agent, 0.5 parts of stabilizer, and 10 parts of ethyl acetate. The polyurea self-healing waterproof coating also includes modified nano silicene, and the weight ratio of the modified nano silicene to the diisocyanate is 5:35. The modified nano silicene is prepared by vapor deposition of heptadecafluorodecyltrimethoxysilane 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 methods of the modified nano-silicene, modified dicyclohexylamine and modified nano-titanium nitride in this embodiment are consistent with those in Example 1. The preparation method of a polyurea self-repairing waterproof coating in this embodiment is consistent with that in Example 1.

[0036] Control group 1: The difference between this embodiment and embodiment 1 is that modified nano-silicene 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, 3.5 parts of modified nano-titanium nitride, 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 preparation method of modified dicyclohexylamine and modified nano-titanium nitride in this embodiment is consistent with that in embodiment 1. The preparation method of a polyurea self-repairing waterproof coating in this embodiment is consistent with that in embodiment 1.

[0037] 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 defoamer, 1.25 parts of leveling agent, 0.3 parts of stabilizer, 12.5 parts of ethyl acetate, the polyurea self-repairing waterproof coating also includes modified nano silicene, the modified nano silicene and diisocyanate are in a weight ratio of 5:30, the modified nano silicene is prepared by vapor deposition of heptadecafluorodecyltrimethoxysilane on the surface of 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.

[0038] 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, 12.5 parts of ethyl acetate, the polyurea self-repairing waterproof coating also includes modified nano-silicene, the modified nano-silicene and diisocyanate are in a weight ratio of 5:30, the modified nano-silicene is prepared by vapor deposition of heptadecafluorodecyltrimethoxysilane on the surface of 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 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.

[0039] 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, a 15N scraping component was used to rub the surface of the coating to scratch the entire surface of the coating. Under the environmental conditions of ambient temperature of 30°C and relative air humidity of 50%, the self-healing of the coating was observed and the self-healing efficiency was calculated by the coating damage area. Each experimental group was set up with three parallel tests, 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. Each experimental group was set up with three parallel tests, and the experimental results were averaged.

[0040]

[0041] Table 1 is 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, on the whole, 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 and reduce the negative impact of the damage on the overall performance of the coating. The water contact angle is also up to 118°. The higher water contact angle means that the coating surface is very hydrophobic, water droplets are not easy to adhere to the coating, and the 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 when making polyurea coating, the self-healing property and waterproof property of polyurea coating can be significantly improved, and the integrity of the coating can be ensured.

[0042]

[0043] Table 2 is a comparison of the waterproof performance test results of the polyurea waterproof coating prepared in Example 1 and the polyurea coatings sold on the market. It can be seen that the polyurea self-repairing waterproof coating prepared in Example 1 exhibits excellent waterproof performance.

[0044] Through the above limited experiments, the application effect of a polyurea self-healing waterproof coating of 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 modern nanotechnology is combined to significantly improve the self-healing performance and waterproof performance of the polyurea coating. 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 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, 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.

[0045] Finally, it should be noted that: Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to 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 protection scope 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 includes: 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-depositing heptadecafluorodecyltrimethoxysilane 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.

2. A polyurea self-repairing waterproof coating according to claim 1, characterized in that: The preparation method of the modified nano-silicene comprises: S11. The nano-silicene is dispersed in anhydrous ethanol and subjected to ultrasonic treatment at a frequency of 40 to 50 kHz. The ultrasonic treatment is performed at room temperature for 0.5 to 1 hour, and then vacuum dried at a temperature of 75 to 85°C. After drying for 6 to 8 hours, the washed nano-silicene is obtained. S12. Place the washed nano-silicene on a heating plate for preheating in a nitrogen atmosphere at a temperature of 105-120°C. After preheating for 0.5-1h, place it in a vapor deposition reaction chamber, control the gas flow rate to 25-40 sccm, load heptadecafluorodecyltrimethoxysilane into the evaporator of the vapor deposition reactor, set the deposition temperature to 145-155°C, turn off the heating device after the deposition reaction for 1-2h, and cool to room temperature; S13. After the vapor deposition reaction is completed, the modified nano-silicene is taken out and washed with anhydrous ethanol for 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 preparation method of the modified dicyclohexylamine comprises: S21. Dissolve dicyclohexylamine in anhydrous ethanol under nitrogen protection and stirring, and heat to 50-60°C. After stirring for 1.5-2 hours, add epichlorohydrin to ensure that the molar ratio of dicyclohexylamine to epichlorohydrin is 1:

1. Continue stirring for 0.5-1 hour, then slowly add 0.1 mol / L sodium hydroxide solution, and react for 4-6 hours to obtain a first mixed solution; S22. The first mixed solution is subjected to high-speed centrifugation at a speed of 6000-8000 rpm for 10-15 min, 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, the speed is set to 80-100 rpm, and the modified dicyclohexylamine is obtained after recrystallization, that is, the modified dicyclohexylamine is prepared by introducing epoxy groups on the surface of dicyclohexylamine.

4. The polyurea self-repairing waterproof coating according to claim 1, characterized in that: The preparation method of the modified nano titanium nitride comprises: S31. Dispersing nano-titanium nitride in a 0.1 mol / L hydrochloric acid solution under stirring and performing ultrasonic treatment, setting the ultrasonic frequency to 40-50 kHz, performing ultrasonic treatment at room temperature for 0.5-1 h, then washing with anhydrous ethanol, and then performing vacuum drying, setting the drying temperature to 65-75°C, and drying for 12-15 h to obtain activated nano-titanium nitride; S32. The activated nano-titanium nitride was dispersed in anhydrous ethanol and subjected to ultrasonic treatment, and sodium dodecylbenzene sulfonate was added, and the ultrasonic frequency was set to 40 to 50 kHz, and the second mixed solution was obtained after ultrasonic treatment at room temperature for 0.5 to 1 h; S33. Dissolve acrylic acid in purified water, stir for 0.5 to 1 h, then slowly add potassium persulfate, continue stirring for 2 to 4 h, then adjust the pH value to 5.5 to 6.0 using phosphate buffered saline to obtain a third mixed solution; S34. The third mixed solution was slowly added to the second mixed solution under stirring to react, the reaction temperature was set to 75 to 85 ° C, the speed was 400 to 500 rpm, and the stirring was performed for 4 to 6 hours to obtain a fourth mixed solution; S35. The fourth mixed solution is subjected to high-speed centrifugation at a rotation speed of 8000-10000 rpm for 15-20 min. The separated solid is washed alternately with anhydrous ethanol and purified water for 3 times and then vacuum dried at a drying temperature of 65-75°C. After drying for 12-15 h, the modified nano-titanium nitride is obtained and ground into powder for later use.

5. The polyurea self-repairing waterproof coating according to claim 4, 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.

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

7. 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).

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

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

10. 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 9, characterized in that: The method comprises the following steps: S41. The polyetheramine was added to ethyl acetate under stirring, and diisocyanate and modified dicyclohexylamine were slowly added after stirring for 0.5 to 1 h, and the reaction was continued with stirring at room temperature for 2 to 4 h to obtain a fifth mixed solution; S42. The modified nano-titanium nitride and the modified nano-silicene were sequentially added to the fifth mixed solution under stirring, and the dispersant, defoamer, leveling agent and stabilizer were slowly added after stirring for 1 to 2 hours, and the reaction was continued at room temperature with stirring for 4 to 6 hours to obtain a sixth mixed solution; S43. The sixth mixed solution is filtered through a 0.5-1 μm filter to obtain a polyurea self-repairing waterproof coating.

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