Photocuring hydrophobic glass repair coating and preparation process thereof

Abstract

The invention discloses a photocuring hydrophobic glass repair coating and a preparation process thereof, and relates to the technical field of coatings. The repair coating is prepared from the following components in parts by mass: 70 to 80 parts of prepolymer, 2 to 5 parts of silica sol, 18 to 20 parts of hexanediol diacrylate and 2 to 5 parts of photoinitiator; wherein the prepolymer is obtained by adopting vegetable oil-based polyurethane acrylate, introducing siloxane for graft polymerization, taking 2, 2-diaminodiphenyl disulfide as a chain extender, and blocking with hydroxyethyl acrylate; the photoinitiator is prepared by doping zinc oxide with rare earth cerium and then modifying with an acrylate blend. The repairing coating is applied to the surface of the glass, plays a good role in protecting the glass, and has good hydrophobicity, antifouling property and mildew resistance while repairing scratches.

Description

Technical Field

[0001] The present invention relates to the technical field of coatings, and specifically to a photocurable hydrophobic glass repair coating and its preparation process. Background Art

[0002] As an important inorganic non-metallic material, glass is widely used in fields such as construction, automotive, electronics, household, and optics. During actual use, glass is prone to mechanical damage (such as scratches and cracks) and environmental erosion (such as ultraviolet rays, humidity, and pollutants). These micro-cracks and scratches not only affect the appearance but may also reduce its strength and safety performance, leading to a decline in its performance and a shortening of its lifespan.

[0003] Traditional glass repair methods mainly rely on physical polishing or chemical etching. However, these methods are not only inefficient, but more importantly, they cannot fundamentally repair the micro-cracks in the glass and may cause secondary damage to the glass surface. With the development of materials science and coating technology, glass surface repair coatings have gradually become an efficient and economical solution. The repair coating forms a functional thin film on the glass surface, which can fill micro-cracks, enhance the surface strength, and provide additional protection functions (such as wear resistance, ultraviolet resistance, and self-cleaning). At the present stage, the introduction of photocuring technology further expands the application market of the coating.

[0004] Although significant progress has been made in the technology of glass surface repair coatings, there are still some challenges. For example, how to optimize the photocuring performance without affecting the transparency of the glass, improve the hardness and wear resistance of the coating; how to improve the anti-fouling and hydrophobic properties of the glass coating surface, and how to develop an environmentally friendly and low-cost production process; Therefore, the present invention provides a preparation process for a photocurable hydrophobic glass repair coating in order to achieve good application effects. Summary of the Invention

[0005] The purpose of the present invention is to provide a photocurable hydrophobic glass repair coating and its preparation process to solve the problems raised in the prior art.

[0006] To achieve the above purpose, the present invention provides the following technical solutions: A preparation process for a photocurable hydrophobic glass repair coating, characterized in that the specific steps are as follows: Step 1: Add a catalyst to isophorone diisocyanate, heat to 60 °C, keep the temperature for reaction until the content of isocyanate groups reaches 23% - 25%, and add an inhibitor to obtain isophorone diisocyanate trimer; Step 2: Mix the trimer prepared in Step 1 with 3-mercaptopropyltrimethoxysilane and triethylamine, react at 75 - 80 °C until the isocyanate group content reaches 16 - 18%, add dibutyltin dilaurate, stir at 45 °C for 15 min, slowly dropwise add the castor oil acetone mixture, continue to react for 1 h, then raise the temperature to 60 °C, keep warm for 4 h, add 2,2-diaminodiphenyl disulfide, 4-methoxyphenol and 2-hydroxyethyl acrylate and continue to react until the isocyanate group content is less than 0.5%, rotary evaporate to remove acetone to obtain a silane-modified polyurethane acrylate prepolymer; Step 3: After mixing and stirring the prepolymer prepared in Step 2 with silica sol for 20 - 30 min, add 1,6-hexanediol diacrylate and a photoinitiator and stir in the dark for 30 - 40 min to obtain a coating. Coat the coating on the glass surface, dry at 60 °C for 3 - 5 min, and then photocure to obtain a repair coating.

[0007] Among them, the preparation steps of the silica sol are as follows: Place tetraethyl orthosilicate in an ethanol solution and stir for 30 min to obtain a mixed solution for standby; after mixing and stirring ammonia water, deionized water and ethanol for 30 min, dropwise add them into the above mixed solution, continue to stir for 3 h and then age for 3 d to obtain sol a; place silicon dioxide in an ethanol solution to obtain sol b; mix sol a and sol b in a volume ratio of 7:3 and stir evenly to obtain the silica sol.

[0008] The photoinitiator includes modified rare earth-doped zinc oxide nanowires, and the preparation steps of the modified rare earth-doped zinc oxide nanowires are as follows: Place zinc acetate and cerium nitrate hexahydrate in deionized water and stir for 20 - 30 min, then dropwise add an alkali solution, and at the same time slowly add an acrylate blend. Stir and react at 40 °C for 2 h, then let stand overnight and centrifuge. After separating the precipitate, wash and dry to obtain modified rare earth-doped zinc oxide nanowires. Among them, the dosage of cerium nitrate hexahydrate is 1 - 3 wt% of zinc acetate; the dosage of the acrylate blend is 2 - 5 wt% of zinc acetate; the acrylate blend is a compound combination of dipropylene glycol diacrylate and trimethylolpropane trimethacrylate in a mass ratio of 1:(1 - 2).

[0009] In Step 1, the dosage of the catalyst is 0.6 - 0.8 wt% of isophorone diisocyanate, and the dosage of the inhibitor is 0.2 - 0.5 wt% of isophorone diisocyanate.

[0010] In Step 2, the dosage ratio of 3-mercaptopropyltrimethoxysilane to the isophorone diisocyanate trimer is 1:(3 - 4); the molar ratio of 3-mercaptopropyltrimethoxysilane, castor oil, 2,2-diaminodiphenyl disulfide and 2-hydroxyethyl acrylate is 1:1:(3 - 4):1.

[0011] In Step 3, the dosages of each component in the coating are as follows: based on mass parts, 70 - 80 parts of prepolymer, 2 - 5 parts of silica sol, 18 - 20 parts of hexanediol diacrylate, and 2 - 5 parts of photoinitiator.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The present invention utilizes the thiol - isocyanate click reaction to introduce 3 - mercaptopropyltrimethoxysilane onto isophorone diisocyanate trimer, improving the compatibility between polyurethane acrylate and silica sol. Meanwhile, under the curing effect, a cross - linking reaction occurs to form a stable siloxane connection network, enhancing the hydrophobic property of the coating. Then, castor oil is introduced as a polyol raw material to participate in the reaction to obtain an intermediate containing - NCO, and 2,2 - diamino - diphenyl disulfide is introduced as a chain extender to introduce disulfide bonds. The synergistic effect with hydrogen bonds endows the polymer with good self - healing ability, and at the same time, the rigid benzene ring structure improves the mechanical properties of the coating; 2. Zinc oxide is added to the photoinitiator. The zinc oxide is doped with rare - earth cerium and then surface - modified with hexanediol diacrylate. Among them, rare - earth cerium effectively improves the photo - initiation efficiency of zinc oxide while reducing the impact on the light transmittance of the coating; the modification of the acrylate blend improves the dispersion degree of zinc oxide in the polymer, reducing agglomeration. In the photo - curing process, the acrylate blend can participate in the polymerization reaction, increasing the cross - linking density and improving the mechanical properties of the repaired coating. In addition, zinc oxide has certain antibacterial properties, expanding the application scope of the coating.

[0013] 3. Polyurethane acrylate and silica sol are mixed to obtain a hybrid coating with silica sol as the inorganic phase. The addition of silica sol can improve the anti - ultraviolet and aging - resistance properties of the material. During the film - forming process, siloxane bonds migrate to the surface, endowing the coating with good hydrophobic properties. Specific Embodiments

[0014] Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0015] In the experiment, the preparation steps of silica sol are as follows: 7 mL of tetraethyl orthosilicate is placed in 33.8 mL of ethanol solution and stirred for 30 min to obtain a mixed solution for standby; 1 mL of ammonia water, 1.12 mL of deionized water, and 33.8 mL of ethanol are mixed and stirred for 30 min, and then dropped into the above - mentioned mixed solution. After magnetic stirring at room temperature for 3 h, it is aged for 3 d to obtain sol a; 1 g of silicon dioxide is dispersed in 100 g of ethanol solution to obtain sol b; sol a and sol b are mixed and stirred evenly according to a volume ratio of 7:3 to obtain silica sol.

[0016] Example 1: This example provides a preparation process for a photo - curable hydrophobic glass repair coating, and the specific steps are as follows: Step 1: Add 0.068 g of tetramethylammonium hydroxide to 10 mL of isophorone diisocyanate, heat to 60 °C, keep the temperature for reaction until the isocyanate group content reaches 24.3%, add 1 drop of phosphoric acid to terminate the reaction, and obtain isophorone diisocyanate trimer; Step 2: Mix the trimer prepared in Step 1 with 2.5 g of 3-mercaptopropyltrimethoxysilane and 0.1 mL of triethylamine, react at 80 °C until the isocyanate group content reaches 17.3%, add 0.03 g of dibutyltin dilaurate, stir at 45 °C for 15 min, slowly add a mixture of 12 g of castor oil and 50 mL of acetone, continue the reaction for 1 h, then raise the temperature to 60 °C, keep the temperature for 4 h, add 12.7 g of 2,2-diaminodiphenyl disulfide, 0.04 g of 4-methoxyphenol and 1.47 g of 2-hydroxyethyl acrylate, and continue the reaction until the isocyanate group content is lower than 0.5%, rotary evaporate to remove acetone, and obtain a silane-modified polyurethane acrylate prepolymer; Step 3: Take 73 parts of the prepolymer prepared in Step 2 and mix it with 4 parts of silica sol and stir for 30 min, then add 20 parts of hexanediol diacrylate and 4 parts of photoinitiator, stir in the dark for 40 min to obtain a coating. Coat the coating on the glass surface, dry at 60 °C for 3 min, and then cure it for 60 s under a 1000 W ultraviolet curing machine to obtain a repair coating.

[0017] Among them, the photoinitiator is modified rare earth-doped zinc oxide nanowhiskers, and the preparation steps of the modified rare earth-doped zinc oxide nanowhiskers are as follows: Put 10 g of zinc acetate and 0.2 g of cerium nitrate hexahydrate in 100 ml of deionized water and stir for 30 min, then dropwise add an alkali solution until the pH is 10, and at the same time slowly add 0.5 mL of acrylate blend. Stir and react at 40 °C for 2 h, then let it stand overnight and then centrifuge. After separating the precipitate, wash and dry to obtain modified rare earth-doped zinc oxide nanowhiskers. Among them, the acrylate blend is a compound combination of dipropylene glycol diacrylate and trimethylolpropane trimethacrylate in a mass ratio of 1:1.5.

[0018] Example 2: This example provides a preparation process of a photocurable hydrophobic glass repair coating, and the specific steps are as follows: Step 1: Add 0.063 g of tetramethylammonium hydroxide to 10 mL of isophorone diisocyanate, heat to 60 °C, keep the temperature for reaction until the isocyanate group content reaches 24.7%, add 1 drop of phosphoric acid to terminate the reaction, and obtain isophorone diisocyanate trimer; Step 2: Mix the trimer prepared in Step 1 with 2.5 g of 3-mercaptopropyltrimethoxysilane and 0.1 mL of triethylamine, react at 80 °C until the isocyanate group content reaches 17.4%, add 0.03 g of dibutyltin dilaurate, stir at 45 °C for 15 min, slowly dropwise add a mixture of 12 g of castor oil and 50 mL of acetone, continue to react for 1 h, then raise the temperature to 60 °C, keep warm for 4 h, add 9.5 g of 2,2-diaminodiphenyl disulfide, 0.04 g of 4-methoxyphenol and 1.48 g of 2-hydroxyethyl acrylate and continue to react until the isocyanate group content is lower than 0.5%, rotary evaporate to remove acetone to obtain a silane-modified polyurethane acrylate prepolymer; Step 3: Take 78 parts of the prepolymer prepared in Step 2 and mix it with 2 parts of silica sol and stir for 30 min, then add 18 parts of hexanediol diacrylate and 4 parts of photoinitiator and stir in the dark for 40 min to obtain a coating. Coat the coating on the glass surface, dry at 60 °C for 3 min, and then cure it under a 1000 W ultraviolet curing machine for 60 s to obtain a repair coating.

[0019] Among them, the photoinitiator is modified rare earth-doped zinc oxide nanowires, and the preparation steps of the modified rare earth-doped zinc oxide nanowires are as follows: Put 10 g of zinc acetate and 0.1 g of cerium nitrate hexahydrate into 100 ml of deionized water and stir for 30 min, then dropwise add an alkali solution until the pH is 10, and at the same time slowly add 0.2 mL of acrylate blend. Stir and react at 40 °C for 2 h, then let it stand overnight and then centrifuge. After separating the precipitate, wash and dry to obtain modified rare earth-doped zinc oxide nanowires. Among them, the acrylate blend is a compound combination of dipropylene glycol diacrylate and trimethylolpropane trimethacrylate in a mass ratio of 1:1.

[0020] Example 3: This example provides a preparation process of a photocurable hydrophobic glass repair coating, and the specific steps are as follows: Step 1: Add 0.068 g of tetramethylammonium hydroxide to 10 mL of isophorone diisocyanate, heat to 60 °C, keep warm and react until the isocyanate group content reaches 23.8%, dropwise add 1 drop of phosphoric acid to terminate the reaction to obtain an isophorone diisocyanate trimer; Step 2: Mix the trimer prepared in Step 1 with 2.5 g of 3-mercaptopropyltrimethoxysilane and 0.1 mL of triethylamine, react at 80 °C until the isocyanate group content reaches 17.4%, add 0.03 g of dibutyltin dilaurate, stir at 45 °C for 15 min, slowly dropwise add a mixture of 12 g of castor oil and 50 mL of acetone, continue to react for 1 h, then raise the temperature to 60 °C, keep warm for 4 h, add 10.5 g of 2,2-diaminodiphenyl disulfide, 0.04 g of 4-methoxyphenol and 1.47 g of 2-hydroxyethyl acrylate and continue to react until the isocyanate group content is lower than 0.5%, rotary evaporate to remove acetone to obtain a silane-modified polyurethane acrylate prepolymer; Step 3: Take 71 parts of the prepolymer prepared in Step 2 and 5 parts of silica sol, mix and stir for 30 min, then add 20 parts of hexanediol diacrylate and 4 parts of photoinitiator, and stir in the dark for 40 min to obtain a coating. Coat the coating on the glass surface, dry it at 60 °C for 3 min, and then cure it for 60 s under a 1000 W ultraviolet curing machine to obtain a repair coating.

[0021] Among them, the photoinitiator is modified rare earth doped nano zinc oxide, and the preparation steps of the modified rare earth doped nano zinc oxide are as follows: Put 10 g of zinc acetate and 0.3 g of cerium nitrate hexahydrate into 100 ml of deionized water, stir for 30 min, then dropwise add an alkali solution until the pH is 10, and slowly add 0.5 mL of acrylate blend at the same time. Stir and react at 40 °C for 2 h, let it stand overnight, then centrifuge, separate the precipitate, wash and dry to obtain modified rare earth doped nano zinc oxide. Among them, the acrylate blend is a compound combination of dipropylene glycol diacrylate and trimethylolpropane trimethacrylate in a mass ratio of 1:2.

[0022] Comparative Example 1: As a control experiment for Example 1, increase the mass fraction of silica sol to 10 parts, and the specific steps are as follows: Step 1: Add 0.068 g of tetramethylammonium hydroxide to 10 mL of isophorone diisocyanate, heat to 60 °C, keep the temperature and react until the isocyanate group content reaches 24.3%, drop 1 drop of phosphoric acid to terminate the reaction, and obtain isophorone diisocyanate trimer; Step 2: Mix the trimer prepared in Step 1 with 2.5 g of 3-mercaptopropyltrimethoxysilane and 0.1 mL of triethylamine, react at 80 °C until the isocyanate group content reaches 17.3%, add 0.03 g of dibutyltin dilaurate, stir at 45 °C for 15 min, slowly dropwise add a mixture of 12 g of castor oil and 50 mL of acetone, continue to react for 1 h, then raise the temperature to 60 °C, keep the temperature for 4 h, add 12.7 g of 2,2-diaminodiphenyl disulfide, 0.04 g of 4-methoxyphenol and 1.47 g of 2-hydroxyethyl acrylate, and continue to react until the isocyanate group content is lower than 0.5%, and rotary evaporate to remove acetone to obtain a silane-modified polyurethane acrylate prepolymer; Step 3: Take 73 parts of the prepolymer prepared in Step 2 and 10 parts of silica sol, mix and stir for 30 min, then add 20 parts of hexanediol diacrylate and 4 parts of photoinitiator, and stir in the dark for 40 min to obtain a coating. Coat the coating on the glass surface, dry it at 60 °C for 3 min, and then cure it for 60 s under a 1000 W ultraviolet curing machine to obtain a repair coating.

[0023] Among them, the photoinitiator is modified rare earth doped nano zinc oxide, and the preparation steps of the modified rare earth doped nano zinc oxide are as follows: Dissolve 10 g of zinc acetate and 0.2 g of cerium nitrate hexahydrate in 100 ml of deionized water and stir for 30 min. Then, add an alkali solution until the pH reaches 10. At the same time, slowly add 0.5 mL of the acrylate blend. Stir and react at 40 °C for 2 h, let it stand overnight, then centrifuge. After separating the precipitate, wash and dry it to obtain modified rare earth-doped nano-zinc oxide. Among them, the acrylate blend is a compound combination of dipropylene glycol diacrylate and trimethylolpropane trimethacrylate in a mass ratio of 1:1.5.

[0024] Comparative Example 2: As a control experiment for Example 1, no modification treatment of rare earth-doped nano-zinc oxide was carried out. The specific steps are as follows: Step 1: Add 0.068 g of tetramethylammonium hydroxide to 10 mL of isophorone diisocyanate, heat to 60 °C, and keep the temperature for reaction until the isocyanate group content reaches 24.3%. Add 1 drop of phosphoric acid to terminate the reaction to obtain isophorone diisocyanate trimer. Step 2: Mix the trimer prepared in Step 1 with 2.5 g of 3-mercaptopropyltrimethoxysilane and 0.1 mL of triethylamine, react at 80 °C until the isocyanate group content reaches 17.3%, add 0.03 g of dibutyltin dilaurate, stir at 45 °C for 15 min, slowly add 12 g of a mixture of castor oil and 50 mL of acetone, continue to react for 1 h, then raise the temperature to 60 °C, keep the temperature for 4 h, add 12.7 g of 2,2-diaminodiphenyl disulfide, 0.04 g of 4-methoxyphenol and 1.47 g of 2-hydroxyethyl acrylate and continue to react until the isocyanate group content is less than 0.5%. Rotate and evaporate acetone to obtain a silane-modified polyurethane acrylate prepolymer. Step 3: Take 73 parts of the prepolymer prepared in Step 2 and mix it with 4 parts of silica sol and stir for 30 min. Then, add 20 parts of hexanediol diacrylate and 4 parts of photoinitiator and stir in the dark for 40 min to obtain a coating. Coat the coating on the glass surface, dry it at 60 °C for 3 min, and then cure it for 60 s under a 1000 W ultraviolet curing machine to obtain a repair coating.

[0025] Among them, the photoinitiator is modified rare earth-doped nano-zinc oxide. The preparation steps of the modified rare earth-doped nano-zinc oxide are as follows: Dissolve 10 g of zinc acetate and 0.2 g of cerium nitrate hexahydrate in 100 ml of deionized water and stir for 30 min. Then, add an alkali solution until the pH reaches 10. Stir and react at 40 °C for 2 h, let it stand overnight, then centrifuge. After separating the precipitate, wash and dry it to obtain rare earth-doped nano-zinc oxide.

[0026] Comparative Example 3: As a control experiment for Example 1, no grafting of 3-mercaptopropyltrimethoxysilane was carried out. The specific steps are as follows: Step 1: Add 0.068 g of tetramethylammonium hydroxide to 10 mL of isophorone diisocyanate, heat to 60 °C, keep the temperature for reaction until the content of isocyanate groups reaches 24.3%, add 1 drop of phosphoric acid to terminate the reaction, and obtain isophorone diisocyanate trimer; Step 2: Mix the trimer prepared in Step 1 with 0.03 g of dibutyltin dilaurate, stir at 45 °C for 15 min, slowly add a mixture of 12 g of castor oil and 50 mL of acetone, continue the reaction for 1 h, then raise the temperature to 60 °C, keep the temperature for 4 h, add 12.7 g of 2,2-diaminodiphenyl disulfide, 0.04 g of 4-methoxyphenol and 1.47 g of 2-hydroxyethyl acrylate, and continue the reaction until the content of isocyanate groups is lower than 0.5%. Rotate and evaporate acetone to obtain a silane-modified polyurethane acrylate prepolymer; Step 3: Take 73 parts of the prepolymer prepared in Step 2 and mix it with 4 parts of silica sol and stir for 30 min, then add 20 parts of hexanediol diacrylate and 4 parts of photoinitiator, stir in the dark for 40 min to obtain a coating. Coat the coating on the glass surface, dry at 60 °C for 3 min, and then cure for 60 s under a 1000 W ultraviolet curing machine to obtain a repair coating.

[0027] Among them, the photoinitiator is modified rare earth-doped zinc oxide nanowires, and the preparation steps of the modified rare earth-doped zinc oxide nanowires are as follows: Put 10 g of zinc acetate and 0.2 g of cerium nitrate hexahydrate into 100 ml of deionized water and stir for 30 min, then dropwise add an alkali solution until the pH is 10, and at the same time slowly add 0.5 mL of acrylate blend. Stir and react at 40 °C for 2 h, then let it stand overnight and centrifuge. After separating the precipitate, wash and dry to obtain modified rare earth-doped zinc oxide nanowires. Among them, the acrylate blend is a compound combination of dipropylene glycol diacrylate and trimethylolpropane trimethacrylate in a mass ratio of 1:1.5.

[0028] Comparative Example 4: As a control experiment of Example 1, do not add 2,2-diaminodiphenyl disulfide. The specific steps are as follows: Step 1: Add 0.068 g of tetramethylammonium hydroxide to 10 mL of isophorone diisocyanate, heat to 60 °C, keep the temperature for reaction until the content of isocyanate groups reaches 24.3%, add 1 drop of phosphoric acid to terminate the reaction, and obtain isophorone diisocyanate trimer; Step 2: Mix the trimer prepared in Step 1 with 2.5 g of 3-mercaptopropyltrimethoxysilane and 0.1 mL of triethylamine, react at 80 °C until the isocyanate group content reaches 17.3%, add 0.03 g of dibutyltin dilaurate, stir at 45 °C for 15 min, slowly dropwise add a mixture of 12 g of castor oil and 50 mL of acetone, continue to react for 1 h, then raise the temperature to 60 °C, keep warm for 4 h, add 0.04 g of 4-methoxyphenol and 1.47 g of 2-hydroxyethyl acrylate and continue to react until the isocyanate group content is less than 0.5%, rotary evaporate to remove acetone to obtain a silane-modified polyurethane acrylate prepolymer; Step 3: Take 73 parts of the prepolymer prepared in Step 2 and mix and stir it with 4 parts of silica sol for 30 min, then add 20 parts of hexanediol diacrylate and 4 parts of photoinitiator and stir in the dark for 40 min to obtain a coating. Coat the coating on the glass surface, dry at 60 °C for 3 min, and then cure for 60 s under a 1000 W ultraviolet curing machine to obtain a repair coating.

[0029] Among them, the photoinitiator is modified rare earth-doped zinc oxide nanowires, and the preparation steps of the modified rare earth-doped zinc oxide nanowires are as follows: Place 10 g of zinc acetate and 0.2 g of cerium nitrate hexahydrate in 100 ml of deionized water and stir for 30 min, then dropwise add an alkali solution until the pH is 10, and at the same time slowly add 0.5 mL of acrylate blend. Stir and react at 40 °C for 2 h, then let it stand overnight and then centrifuge. After separating the precipitate, wash and dry to obtain modified rare earth-doped zinc oxide nanowires. Among them, the acrylate blend is a compound combination of dipropylene glycol diacrylate and trimethylolpropane trimethacrylate in a mass ratio of 1:1.5.

[0030] Detection test 1. Water contact angle test: Use a JC2000D1 type contact angle measuring instrument to measure the water contact angle of the repair coatings prepared in Examples 1-3 and Comparative Examples 1-4. Measure 5 data for each sample and take the average value and record it in Table 1; 2. Transmittance test: Use an ultraviolet spectrophotometer to measure the transmittance of the repair coatings prepared in Examples 1-3 and Comparative Examples 1-4, and record the data in Table 1; 3. Coating surface mechanical property test: The hardness test refers to GB / T 6739; the adhesion test refers to GB / T928; the above data are recorded in Table 1.

[0031] Table 1 Conclusion: From the above data, it can be seen that Example 1 has achieved good results in comprehensive performance compared with Examples 2 and 3; in Comparative Example 1, increasing the composition of silica sol results in a decrease in the mechanical properties of the coating; in Comparative Example 2, without zinc oxide modification, the dispersion effect becomes poor, resulting in a significant decrease in the transmittance of the coating, and at the same time, the mechanical properties are also affected to a certain extent; in Comparative Example 3, without silicone grafting, the hydrophobic property decreases, and the other properties are all affected to a certain extent; in Comparative Example 4, without adding 2,2-diaminodiphenyl disulfide, the hardness and adhesion of the coating decrease.

[0032] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements on some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A preparation process of a photocurable hydrophobic glass repair coating, characterized in that, The specific steps are as follows: Step 1: Add a catalyst to isophorone diisocyanate, heat it to 60 °C, keep the temperature for reaction until the content of isocyanate groups reaches 23%-25%, then add an inhibitor to obtain isophorone diisocyanate trimer; Step 2: Mix the trimer prepared in Step 1 with 3-mercaptopropyltrimethoxysilane and triethylamine, react at 75-80 °C until the content of isocyanate groups reaches 16-18%, add dibutyltin dilaurate, stir at 45 °C for 15 min, slowly dropwise add a castor oil acetone mixture, continue to react for 1 h, then raise the temperature to 60 °C, keep the temperature for 4 h, add 2,2-diaminodiphenyl disulfide, 4-methoxyphenol and 2-hydroxyethyl acrylate and continue to react until the content of isocyanate groups is lower than 0.5%, rotary evaporate acetone to obtain a silane-modified polyurethane acrylate prepolymer; Step 3: After mixing and stirring the prepolymer prepared in Step 2 with silica sol for 20-30 min, add hexanediol diacrylate and a photoinitiator, stir in the dark for 30-40 min to obtain a coating. Coat the coating on the glass surface, dry at 60 °C for 3-5 min, and then photocure to obtain a repair coating.

2. The preparation process of a photocurable hydrophobic glass repair coating according to claim 1, characterized in that, The preparation steps of silica sol are as follows: Place tetraethyl orthosilicate in an ethanol solution and stir for 30 min to obtain a mixed solution for standby; Mix ammonia water, deionized water and ethanol and stir for 30 min, then dropwise add the above mixed solution, continue to stir for 3 h and then age for 3 d to obtain sol a; Place silicon dioxide in an ethanol solution to obtain sol b; Mix sol a and sol b in a volume ratio of 7:3 and stir evenly to obtain the silica sol.

3. The preparation process of a photocurable hydrophobic glass repair coating according to claim 1, characterized in that The photoinitiator includes modified rare earth-doped zinc oxide nanoparticles, and the preparation steps of the modified rare earth-doped zinc oxide nanoparticles are as follows: Place zinc acetate and cerium nitrate hexahydrate in deionized water and stir for 20-30 min, then dropwise add an alkali solution, and at the same time slowly add an acrylate blend. Stir and react at 40 °C for 2 h, then let stand overnight and centrifuge. After separating the precipitate, wash and dry to obtain modified rare earth-doped zinc oxide nanoparticles.

4. The preparation process of a photocurable hydrophobic glass repair coating according to claim 3, characterized in that, The dosage of cerium nitrate hexahydrate is 1-3 wt% of zinc acetate; The dosage of the acrylate blend is 2-5 wt% of zinc acetate; The acrylate blend is a compound combination of dipropylene glycol diacrylate and trimethylolpropane trimethacrylate in a mass ratio of 1:(1-2).

5. The preparation process of a photocurable hydrophobic glass repair coating according to claim 1, characterized in that, In Step 1, the dosage of the catalyst is 0.6-0.8 wt% of isophorone diisocyanate, and the dosage of the inhibitor is 0.2-0.5 wt% of isophorone diisocyanate.

6. The preparation process of a photocurable hydrophobic glass repair coating according to claim 1, characterized in that In Step 2, the dosage ratio of 3-mercaptopropyltrimethoxysilane to isophorone diisocyanate trimer is 1:(3-4); The molar ratio of 3-mercaptopropyltrimethoxysilane, castor oil, 2,2-diaminodiphenyl disulfide and 2-hydroxyethyl acrylate is 4:1:(3-4):

4.

7. The preparation process of a photocurable hydrophobic glass repair coating according to claim 1, characterized in that, In Step 3, the dosage of each component in the coating is as follows: by mass, 70-80 parts of prepolymer, 2-5 parts of silica sol, 18-20 parts of hexanediol diacrylate and 2-5 parts of photoinitiator.

8. A photocurable hydrophobic glass repair coating, characterized in that, The repair coating is prepared by the preparation method described in Claim 1.

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