Self-healing waterproof coating material and preparation method thereof

Abstract

The invention relates to the technical field of coating materials, and particularly discloses a self-healing waterproof coating material and a preparation method thereof.According to the self-healing waterproof coating material and the preparation method thereof, ZrO2 wraps the surface of nano SiO2, and the corrosion resistance and hardness of a coating are improved; then boric acid groups are introduced to the surfaces of inorganic particles, so that the coating material is endowed with an excellent self-healing function; the modified styrene-acrylic emulsion has good hardness, strength and rigidity, but is insufficient in flexibility, the flexibility of the coating material is improved by introducing the organic silicon modified acrylic emulsion, and a polysiloxane chain segment in organic silicon modified acrylic acid improves the chain segment activity of a polymer matrix, so that when the coating is damaged, the service life of the coating material is prolonged, and the service life of the coating material is prolonged. And groups such as carboxyl and amino in a modified styrene-acrylic emulsion polymer chain segment are more easily diffused to a crack interface to promote fracture and recombination of boric acid ester bonds and hydrogen bonds, so that the self-healing function of the coating material is improved.

Description

Technical Field

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

[0002] Traditional coating systems, combining film-forming resins (such as epoxies, polyurethanes, and acrylates) with functional fillers, have achieved significant progress in corrosion protection, wear resistance, insulation, and optical properties. However, when exposed to complex mechanical stresses, chemical corrosion, and thermal shock, these coatings are prone to microcracks and even partial flaking, resulting in a sharp decline in protective effectiveness and significantly shortening the service life of the underlying device.

[0003] The self-healing method currently used in coatings is mainly intrinsic self-healing. Under external stimulation, the destroyed cross-linked network is re-cross-linked through the flow of reversible bonds such as DA bonds, ester bonds, and coordination bonds, so that the microcracks are refilled, realizing the self-healing function of the material. However, intrinsic self-healing materials that rely on dynamic bonds often have insufficient hardness, modulus and wear resistance due to the excessive flexibility of the molecular chain.

[0004] For example, Chinese patent document CN202210104931.0 discloses a self-healing water-based polyurethane based on dual drive of acylhydrazone bonds and multiple hydrogen bonds, and its preparation method and application. A polyurethane prepolymer is obtained by reacting diisocyanate, oligomer polyol, small molecule diol, acylhydrazone diol, and hydrophilic chain extender, which is then neutralized by adding a neutralizer, and then emulsified with deionized water to obtain an aqueous polyurethane emulsion containing acylhydrazone bonds. Finally, it is mixed with a tannic acid solution to generate hydrogen bonds between the tannic acid and the polyurethane main chain to form physical crosslinks, thereby preparing a self-healing water-based polyurethane material with excellent mechanical properties and high healing efficiency, but its hardness and wear resistance still need to be further improved. Summary of the Invention

[0005] In view of the deficiencies in the prior art, the object of the present invention is to provide a self-healing waterproof coating material and a preparation method thereof.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: A method for preparing a self-healing waterproof coating material comprises the following steps: S1. Preparation of composite silicon dioxide The zirconium salt is dissolved in deionized water, and then nano-silicon dioxide is added thereto, dispersed evenly by ultrasonication, heated to remove moisture, dried, calcined, and ground to obtain composite silicon dioxide.

[0007] In this step, the mass ratio of nano-silica and zirconium salt is 8-12:2-4. In some embodiments of the present invention, for example, 8:2, 8:3, 8:4, 10:2, 10:3, 10:4, 12:2, 12:3, 12:4 can be selected, but it is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0008] In this step, the zirconium salt selected is a soluble zirconium salt, for example, zirconium oxychloride or zirconium nitrate.

[0009] In this step, the calcination temperature is 400-500° C. and the calcination time is 1-2 hours.

[0010] In this step, by wrapping ZrO2 on the surface of nano-SiO2, ZrO2 has a higher hardness, thereby improving the hardness of the coating material. At the same time, ZrO2 also has excellent chemical inertness, corrosion resistance and high thermal stability. Introducing it into the coating material can enhance the coating's ability to resist erosion by chemical media such as acids, alkalis, and salts, and can improve the coating's corrosion resistance to a certain extent.

[0011] S2. Preparation of modifier 4-vinylphenylboronic acid is added to an organic solvent, and then vinyltriethoxysilane and benzoyl peroxide are added thereto, and the mixture is heated for reaction to obtain a modifier.

[0012] In this step, the mass ratio of 4-vinylphenylboronic acid, vinyltriethoxysilane and benzoyl peroxide is 10:8-12:0.1-0.2. In some embodiments of the present invention, for example, 10:8:0.1, 10:8:0.2, 10:10:0.1, 10:10:0.2, 10:12:0.1, and 10:12:0.2 can be selected, but the ratio is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0013] In this step, the heating reaction temperature is 60-80°C, for example, 60°C, 65°C, 70°C, 75°C, and 80°C can be selected; the heating reaction time is 3-5h, for example, 3h, 3.5h, 4h, 4.5h, and 5h can be selected, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0014] In this step, 4-vinylphenylboronic acid and vinyltriethoxysilane undergo a double bond addition reaction under the action of an initiator to generate a bifunctional polymer containing a boronic acid group and a siloxane group.

[0015] S3. Preparation of modified silica The composite silicon dioxide is dispersed in an ethanol aqueous solution, and then a modifier is added thereto, and the mixture is stirred and refluxed to react, thereby obtaining the modified silicon dioxide.

[0016] In this step, the mass ratio of composite silica to modifier is 10-15:2-4. In some embodiments of the present invention, for example, 10:2, 10:3, 10:4, 12:2, 12:3, 12:4, 15:2, 15:3, 15:4 can be selected, but it is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0017] In this step, the temperature of the stirring reflux reaction is 40-60° C., and the stirring reflux reaction time is 2-4 h.

[0018] In this step, the hydroxyl groups (-OH) on the surface of the composite silica react with the siloxane groups of the modifier to form a covalent grafting layer. By introducing boric acid groups onto the surface of the inorganic particles, the coating material is endowed with excellent self-healing properties. At the same time, the siloxane chain segments enhance the compatibility between the inorganic particles and the organic phase, avoiding the generation of interface defects.

[0019] S4. Preparation of modified styrene-acrylic emulsion Sodium dodecylbenzenesulfonate, nonylphenol polyoxyethylene ether and tert-dodecyl mercaptan are added to deionized water, stirred evenly, and nitrogen is introduced to expel the air. Styrene, 2-(trifluoromethyl)acrylic acid and 6-amino-2-mercaptobenzothiazole are then added thereto. The mixture is stirred and heated to 50-60°C. Ammonium persulfate is added and the mixture is stirred for reaction. After the reaction is completed, the mixture is cooled to room temperature to obtain a modified styrene-acrylic emulsion.

[0020] In this step, the mass ratio of sodium dodecylbenzenesulfonate, nonylphenol polyoxyethylene ether, tert-dodecyl mercaptan, deionized water, styrene, 2-(trifluoromethyl)acrylic acid, 6-amino-2-mercaptobenzothiazole and ammonium persulfate is 1-3:1-3:2-4:100-150:20-25:10-20:8-12:0.2-0.4.

[0021] In this step, the stirring reaction temperature is 50-60° C., and the stirring reaction time is 2-4 h.

[0022] In this step, by adding 2-(trifluoromethyl) acrylic acid monomer and 6-amino-2-mercaptobenzothiazole monomer, the fluorine element in the 2-(trifluoromethyl) acrylic acid monomer enhances the hydrophobicity of the coating material; the benzothiazole group in the 6-amino-2-mercaptobenzothiazole monomer can be adsorbed on the surface of the metal substrate to form a passivation film, thereby improving the corrosion resistance of the coating material; at the same time, the amino group in the 6-amino-2-mercaptobenzothiazole monomer can form a dynamic boron-nitrogen bond with the boric acid group, further improving the self-healing function of the coating material.

[0023] S5. Preparation of self-healing waterproof coating material The modified silicon dioxide, modified styrene acrylic emulsion and silicone modified acrylic emulsion are stirred and mixed evenly, and physically degassed to obtain a self-healing waterproof coating material.

[0024] In this step, the mass ratio of modified silica, modified styrene-acrylic emulsion and silicone-modified acrylic emulsion is 5-10:100:15-25. In some embodiments of the present invention, for example, 5:100:15, 5:100:20, 5:100:25, 8:100:15, 8:100:28, 8:100:20, 8:100:25, 10:100:15, 10:100:20, and 10:100:25 can be selected, but the ratio is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0025] In this step, the modified styrene acrylic emulsion has good hardness, strength and rigidity, but its flexibility is insufficient. The present invention introduces an organosilicon-modified acrylic emulsion. The polysiloxane chain segments in the organosilicon-modified acrylic improve the flexibility of the coating material, thereby increasing the segment mobility of the polymer matrix. When the coating is damaged, the carboxyl group, amino group and other groups in the modified styrene acrylic emulsion polymer segment are more likely to diffuse to the crack interface, promoting the breaking and recombination of borate bonds and hydrogen bonds, thereby improving the self-healing function of the coating material; at the same time, the polysiloxane itself has low surface energy and excellent hydrophobicity, further improving the waterproof performance of the coating material.

[0026] The present invention also provides a self-healing waterproof coating material prepared by the above preparation method.

[0027] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention wraps ZrO2 on the surface of nano-SiO2. ZrO2 has a higher hardness, thereby improving the hardness of the coating material. At the same time, ZrO2 also has excellent chemical inertness, corrosion resistance and high thermal stability. Introducing it into the coating material can enhance the coating's ability to resist erosion by chemical media such as acids, alkalis, and salts, and can improve the coating's corrosion resistance to a certain extent.

[0028] (2) In the present invention, 4-vinylphenylboronic acid and vinyltriethoxysilane undergo a double bond addition reaction under the action of an initiator to generate a bifunctional polymer containing a boronic acid group and a siloxane group. Subsequently, the silanol (Si-OH) on the surface of the composite silica reacts with the siloxane group to form a covalent grafting layer. By introducing the boronic acid group into the surface of the inorganic particles, the coating material is endowed with excellent self-healing function. At the same time, the siloxane chain segment improves the compatibility between the inorganic particles and the organic phase, avoiding the generation of interface defects.

[0029] (3) The present invention adds 2-(trifluoromethyl) acrylic acid monomer and 6-amino-2-mercaptobenzothiazole monomer. The fluorine element in the 2-(trifluoromethyl) acrylic acid monomer enhances the hydrophobicity of the coating material; the benzothiazole group in the 6-amino-2-mercaptobenzothiazole monomer can be adsorbed on the surface of the metal substrate to form a passivation film, thereby improving the corrosion resistance of the coating material; at the same time, the amino group in the 6-amino-2-mercaptobenzothiazole monomer can form a dynamic boron-nitrogen bond with the boric acid group, further improving the self-healing function of the coating material.

[0030] (4) The modified styrene acrylic emulsion provided by the present invention has good hardness, strength and rigidity, but its flexibility is insufficient. The present invention introduces silicone modified acrylic emulsion. The polysiloxane chain segment in the silicone modified acrylic improves the flexibility of the coating material, thereby increasing the chain segment mobility of the polymer matrix, so that when the coating is damaged, the carboxyl group, amino group and other groups in the modified styrene acrylic emulsion polymer chain segment are more likely to diffuse to the crack interface, promote the breaking and recombination of borate bonds and hydrogen bonds, thereby improving the self-healing function of the coating material; at the same time, the polysiloxane itself has low surface energy and excellent hydrophobicity, which further improves the waterproof performance of the coating material. DETAILED DESCRIPTION

[0031] The present invention is further described in detail below through specific preferred embodiments, but the present invention is not limited to the following embodiments.

[0032] It should be noted that, unless otherwise specified, all chemical reagents involved in the present invention were purchased through commercial channels.

[0033] The particle size of the nano-silicon dioxide used in the examples provided by the present invention is 40-60 nm; the model of the organosilicon-modified acrylic emulsion is DB2105, purchased from Hefei Dibang Nanotechnology Co., Ltd.

[0034] Example 1 A method for preparing a self-healing waterproof coating material comprises the following steps: S1. Dissolve 2 g of zirconium oxychloride in 100 mL of deionized water, then add 8 g of nano-silica thereto, disperse evenly by ultrasonication, heat and stir to remove moisture, dry, place in a heating furnace, calcine at 500° C. for 1 h, and grind to obtain composite silica; S2, 10g of 4-vinylphenylboronic acid was added to 100mL of organic solvent DMF, and then 8g of vinyltriethoxysilane and 0.1g of benzoyl peroxide were added thereto, and the mixture was heated at 80°C for 3h. After the reaction was completed, the reaction solution was poured into ice water to precipitate the product, which was collected by filtration, washed, and dried to obtain a modifier; S3, dispersing 10 g of composite silica in 100 mL of ethanol-water solution (the volume ratio of ethanol to water is 3:1), then adding 2 g of modifier thereto, stirring and refluxing at 60° C. for 2 h to obtain modified silica; S4, 2g of sodium dodecylbenzenesulfonate, 2g of nonylphenol polyoxyethylene ether NP-10 and 3g of tert-dodecyl mercaptan were added to 100g of deionized water, stirred evenly, and nitrogen was introduced to expel the air. Then, 20g of styrene, 10g of 2-(trifluoromethyl)acrylic acid and 8g of 6-amino-2-mercaptobenzothiazole were added thereto, and the mixture was stirred and heated to 60°C. 0.2g of ammonium persulfate was added, and the mixture was stirred and reacted at 60°C for 2h. After the reaction was completed, the mixture was cooled to room temperature to obtain a modified styrene-acrylic emulsion; S5. Evenly stir and mix 5 g of modified silica, 100 g of modified styrene acrylic emulsion and 15 g of silicone modified acrylic emulsion, and perform physical degassing to obtain a self-healing waterproof coating material.

[0035] Example 2 A method for preparing a self-healing waterproof coating material comprises the following steps: S1. Dissolve 4 g of zirconium oxychloride in 100 mL of deionized water, then add 12 g of nano-silica thereto, disperse evenly by ultrasonication, heat and stir to remove moisture, dry, place in a heating furnace, calcine at 500° C. for 1 h, and grind to obtain composite silica; S2, 10g of 4-vinylphenylboronic acid was added to 100mL of organic solvent DMF, and then 12g of vinyltriethoxysilane and 0.2g of benzoyl peroxide were added thereto, and the mixture was heated at 80°C for 3h. After the reaction was completed, the reaction solution was poured into ice water to precipitate the product, which was collected by filtration, washed, and dried to obtain a modifier; S3, dispersing 15 g of composite silica in 100 mL of ethanol-water solution (the volume ratio of ethanol to water is 3:1), then adding 4 g of modifier thereto, stirring and refluxing at 60° C. for 2 h to obtain modified silica; S4, 1g of sodium dodecylbenzenesulfonate, 1g of nonylphenol polyoxyethylene ether NP-10 and 2g of tert-dodecyl mercaptan were added to 100g of deionized water, stirred evenly, and nitrogen was introduced to expel the air. Then, 25g of styrene, 15g of 2-(trifluoromethyl)acrylic acid and 10g of 6-amino-2-mercaptobenzothiazole were added thereto, and the mixture was heated to 60°C with stirring, and 0.3g of ammonium persulfate was added. The mixture was stirred and reacted at 60°C for 2h. After the reaction was completed, the mixture was cooled to room temperature to obtain a modified styrene-acrylic emulsion; S5. Stir and mix 10 g of modified silica, 100 g of modified styrene acrylic emulsion and 25 g of silicone modified acrylic emulsion evenly, and perform physical degassing to obtain a self-healing waterproof coating material.

[0036] Example 3 A method for preparing a self-healing waterproof coating material comprises the following steps: S1. Dissolve 3 g of zirconium oxychloride in 100 mL of deionized water, then add 10 g of nano-silica thereto, disperse evenly by ultrasonication, heat and stir to remove moisture, dry, place in a heating furnace, calcine at 500° C. for 1 h, and grind to obtain composite silica; S2, 10g of 4-vinylphenylboronic acid was added to 100mL of organic solvent DMF, and then 10g of vinyltriethoxysilane and 0.2g of benzoyl peroxide were added thereto, and the mixture was heated at 80°C for 3h. After the reaction was completed, the reaction solution was poured into ice water to precipitate the product, which was collected by filtration, washed, and dried to obtain a modifier; S3, dispersing 12 g of composite silica in 100 mL of ethanol-water solution (the volume ratio of ethanol to water is 3:1), then adding 3 g of modifier thereto, stirring and refluxing at 60° C. for 2 h to obtain modified silica; S4, 3g of sodium dodecylbenzenesulfonate, 1g of nonylphenol polyoxyethylene ether NP-10 and 4g of tert-dodecyl mercaptan were added to 100g of deionized water, stirred evenly, and nitrogen was introduced to expel the air. Then, 25g of styrene, 20g of 2-(trifluoromethyl)acrylic acid and 12g of 6-amino-2-mercaptobenzothiazole were added thereto, and the mixture was stirred and heated to 60°C. 0.4g of ammonium persulfate was added, and the mixture was stirred and reacted at 60°C for 2h. After the reaction was completed, the mixture was cooled to room temperature to obtain a modified styrene-acrylic emulsion; S5. Stir and mix 8 g of modified silica, 100 g of modified styrene acrylic emulsion and 20 g of silicone modified acrylic emulsion, and perform physical degassing to obtain a self-healing waterproof coating material.

[0037] Comparative Example 1 A method for preparing a self-healing waterproof coating material comprises the following steps: S1. Add 10 g of 4-vinylphenylboronic acid to 100 mL of DMF, then add 8 g of vinyltriethoxysilane and 0.1 g of benzoyl peroxide, and heat the mixture at 80° C. for 3 h. After the reaction is completed, pour the reaction solution into ice water to precipitate the product, collect it by filtration, wash it, and dry it to obtain a modifier; S2. Disperse 10 g of nano-silica in 100 mL of ethanol-water solution (the volume ratio of ethanol to water is 3:1), then add 2 g of a modifier thereto, and stir under reflux at 60° C. for 2 h to obtain modified silica; S3, 2g of sodium dodecylbenzenesulfonate, 2g of nonylphenol polyoxyethylene ether NP-10 and 3g of tert-dodecyl mercaptan were added to 100g of deionized water, stirred evenly, and nitrogen was introduced to expel the air. Then, 20g of styrene, 10g of 2-(trifluoromethyl) acrylic acid and 8g of 6-amino-2-mercaptobenzothiazole were added thereto, and the mixture was stirred and heated to 60°C. 0.2g of ammonium persulfate was added, and the mixture was stirred and reacted at 60°C for 2h. After the reaction was completed, the mixture was cooled to room temperature to obtain a modified styrene-acrylic emulsion; S4. Stir and mix 5 g of modified silica, 100 g of modified styrene acrylic emulsion and 15 g of silicone modified acrylic emulsion, and perform physical degassing to obtain a self-healing waterproof coating material.

[0038] Compared with Example 1, Comparative Example 1 does not use ZrO2 to wrap the nano-silicon dioxide, and other conditions remain unchanged.

[0039] Comparative Example 2 A method for preparing a self-healing waterproof coating material comprises the following steps: S1. Dissolve 2 g of zirconium oxychloride in 100 mL of deionized water, then add 8 g of nano-silica thereto, disperse evenly by ultrasonication, heat and stir to remove moisture, dry, place in a heating furnace, calcine at 500° C. for 1 h, and grind to obtain composite silica; S2, 2g of sodium dodecylbenzenesulfonate, 2g of nonylphenol polyoxyethylene ether NP-10 and 3g of tert-dodecyl mercaptan were added to 100g of deionized water, stirred evenly, and nitrogen was introduced to expel the air. Then, 20g of styrene, 10g of 2-(trifluoromethyl) acrylic acid and 8g of 6-amino-2-mercaptobenzothiazole were added thereto, and the mixture was stirred and heated to 60°C. 0.2g of ammonium persulfate was added, and the mixture was stirred and reacted at 60°C for 2h. After the reaction was completed, the mixture was cooled to room temperature to obtain a modified styrene-acrylic emulsion; S3. Stir and mix 5 g of composite silica, 100 g of modified styrene acrylic emulsion and 15 g of silicone modified acrylic emulsion, and perform physical degassing to obtain a self-healing waterproof coating material.

[0040] Compared with Example 1, Comparative Example 2 does not use a modifier to modify the composite silicon dioxide.

[0041] Comparative Example 3 A method for preparing a self-healing waterproof coating material comprises the following steps: S1. Dissolve 2 g of zirconium oxychloride in 100 mL of deionized water, then add 8 g of nano-silica thereto, disperse evenly by ultrasonication, heat and stir to remove moisture, dry, place in a heating furnace, calcine at 500° C. for 1 h, and grind to obtain composite silica; S2, 10g of 4-vinylphenylboronic acid was added to 100mL of organic solvent DMF, and then 8g of vinyltriethoxysilane and 0.1g of benzoyl peroxide were added thereto, and the mixture was heated at 80°C for 3h. After the reaction was completed, the reaction solution was poured into ice water to precipitate the product, which was collected by filtration, washed, and dried to obtain a modifier; S3, dispersing 10 g of composite silica in 100 mL of ethanol-water solution (the volume ratio of ethanol to water is 3:1), then adding 2 g of modifier thereto, stirring and refluxing at 60° C. for 2 h to obtain modified silica; S4, 2g of sodium dodecylbenzenesulfonate, 2g of nonylphenol polyoxyethylene ether NP-10 and 3g of tert-dodecyl mercaptan were added to 100g of deionized water, stirred evenly, and nitrogen was introduced to expel the air. Then, 20g of styrene and 10g of 2-(trifluoromethyl)acrylic acid were added thereto, and the mixture was heated to 60°C with stirring, and 0.2g of ammonium persulfate was added. The mixture was stirred and reacted at 60°C for 2h. After the reaction was completed, the mixture was cooled to room temperature to obtain a modified styrene-acrylic emulsion; S5. Evenly stir and mix 5 g of modified silica, 100 g of modified styrene acrylic emulsion and 15 g of silicone modified acrylic emulsion, and perform physical degassing to obtain a self-healing waterproof coating material.

[0042] Compared with Example 1, Comparative Example 3 does not add 6-amino-2-mercaptobenzothiazole.

[0043] Comparative Example 4 A method for preparing a self-healing waterproof coating material comprises the following steps: S1. Dissolve 2 g of zirconium oxychloride in 100 mL of deionized water, then add 8 g of nano-silica thereto, disperse evenly by ultrasonication, heat and stir to remove moisture, dry, place in a heating furnace, calcine at 500° C. for 1 h, and grind to obtain composite silica; S2, 10g of 4-vinylphenylboronic acid was added to 100mL of organic solvent DMF, and then 8g of vinyltriethoxysilane and 0.1g of benzoyl peroxide were added thereto, and the mixture was heated at 80°C for 3h. After the reaction was completed, the reaction solution was poured into ice water to precipitate the product, which was collected by filtration, washed, and dried to obtain a modifier; S3, dispersing 10 g of composite silica in 100 mL of ethanol-water solution (the volume ratio of ethanol to water is 3:1), then adding 2 g of modifier thereto, stirring and refluxing at 60° C. for 2 h to obtain modified silica; S4, 2g of sodium dodecylbenzenesulfonate, 2g of nonylphenol polyoxyethylene ether NP-10 and 3g of tert-dodecyl mercaptan were added to 100g of deionized water, stirred evenly, and nitrogen was introduced to expel the air. Then, 20g of styrene, 10g of 2-(trifluoromethyl)acrylic acid and 8g of 6-amino-2-mercaptobenzothiazole were added thereto, and the mixture was stirred and heated to 60°C. 0.2g of ammonium persulfate was added, and the mixture was stirred and reacted at 60°C for 2h. After the reaction was completed, the mixture was cooled to room temperature to obtain a modified styrene-acrylic emulsion; S5. Stir and mix 5 g of modified silica and 100 g of modified styrene-acrylic emulsion evenly, and perform physical degassing to obtain a self-healing waterproof coating material.

[0044] Compared with Example 1, Comparative Example 4 does not add silicone-modified acrylic emulsion.

[0045] The coating materials prepared in Examples 1-3 and Comparative Examples 1-4 were subjected to performance testing, and the specific steps were as follows: The coating materials prepared in Examples 1-3 and Comparative Examples 1-4 were coated on medium density boards with a coating thickness of 0.5 mm and dried at 60° C. to obtain coating films.

[0046] Pencil hardness: tested in accordance with standard GB / T 6739-2022; Wear resistance: Test the wear resistance of the coating according to GB / T 1768-2006; Self-healing performance test: Use a paper cutter to cut a crack with a width of 2-3 mm in the coating film, measure the initial crack width d0, then place the cracked coating film in a natural environment (23±2℃, RH 50±10%) for 4 hours, measure the crack width d1 again, and calculate the healing rate, where the healing rate = (d0-d1) / d0×100%; Corrosion resistance test: The coating materials prepared in Examples 1-3 and Comparative Examples 1-4 were sprayed onto the surface of Q345 steel to a thickness of 200 μm and dried at 60°C to form a passivation film on the surface of the steel. The steels coated with the passivation film were immersed in a 3.5% sodium chloride solution. The corrosion resistance of the samples was evaluated by observing the time it took for white rust to appear, where ">60 days" means more than 60 days but less than 70 days, ">70 days" means more than 70 days but less than 80 days, and so on. The test results are shown in Table 1.

[0047] Table 1 Performance test results Finally, it should be noted that the above embodiments do not limit the present invention in any form. Those skilled in the art will appreciate that modifications and improvements can be made based on the present invention. Therefore, any modifications or improvements made without departing from the spirit of the present invention are intended to fall within the scope of protection claimed in the present invention.

Claims

1. A method for preparing a self-healing waterproof coating material, characterized in that: The steps include: S1. Dissolve zirconium salt in deionized water, then add nano-silica thereto, disperse uniformly by ultrasonication, heat to remove moisture, dry, calcine, and grind to obtain composite silica; S2, adding 4-vinylphenylboronic acid to an organic solvent, then adding vinyltriethoxysilane and benzoyl peroxide thereto, heating for reaction, to obtain a modifier; S3, dispersing the composite silicon dioxide in an ethanol aqueous solution, then adding a modifier thereto, stirring and refluxing the mixture to obtain modified silicon dioxide; S4, adding sodium dodecylbenzenesulfonate, nonylphenol polyoxyethylene ether and tert-dodecyl mercaptan to deionized water, stirring evenly, introducing nitrogen to expel air, then adding styrene, 2-(trifluoromethyl) acrylic acid and 6-amino-2-mercaptobenzothiazole thereto, stirring and heating to 50-60° C., adding ammonium persulfate, stirring and reacting, and after the reaction is completed, cooling to room temperature to obtain a modified styrene-acrylic emulsion; S5. Evenly mix the modified silica, modified styrene acrylic emulsion and silicone modified acrylic emulsion, and perform physical degassing to obtain a self-healing waterproof coating material.

2. The preparation method according to claim 1, characterized in that In step S1, the mass ratio of nano-silicon dioxide to zirconium salt is 8-12:2-4.

3. The preparation method according to claim 1, characterized in that In step S2, the mass ratio of 4-vinylphenylboric acid, vinyltriethoxysilane and benzoyl peroxide is 10:8-12:0.1-0.

2.

4. The preparation method according to claim 1, characterized in that In step S2, the heating reaction temperature is 60-80° C., and the heating reaction time is 3-5 hours.

5. The preparation method according to claim 1, characterized in that In step S3, the mass ratio of the composite silica to the modifier is 10-15:2-4.

6. The preparation method according to claim 1, characterized in that In step S3, the temperature of the stirring reflux reaction is 40-60° C., and the time of the stirring reflux reaction is 2-4 h.

7. The preparation method according to claim 1, characterized in that In step S4, the mass ratio of sodium dodecylbenzenesulfonate, nonylphenol polyoxyethylene ether, tert-dodecyl mercaptan, deionized water, styrene, 2-(trifluoromethyl)acrylic acid, 6-amino-2-mercaptobenzothiazole and ammonium persulfate is 1-3:1-3:2-4:100-150:20-25:10-20:8-12:0.2-0.

4.

8. The preparation method according to claim 1, characterized in that In step S5, the mass ratio of modified silica, modified styrene acrylic emulsion and silicone modified acrylic emulsion is 5-10:100:15-25.

9. The self-healing waterproof coating material prepared by the preparation method according to any one of claims 1 to 8.

Images