Preparation method of transparent super-hydrophobic coating

Abstract

The invention discloses a preparation method of a transparent super-hydrophobic coating, and belongs to the technical field of building glass. Comprising the following raw materials in parts by weight: 4-6 parts of tin antimony oxide, 10-15 parts of nano silicon dioxide, 80-100 parts of a solvent, 0.3-0.5 part of a curing agent, 3-9 parts of an anti-ultraviolet agent, 53-65 parts of vinyl-terminated polydimethylsiloxane and 26-38 parts of hydrogen-containing silicone oil. Wherein the vinyl-terminated polydimethylsiloxane and the hydrogen-containing silicone oil can be cross-linked and cured to form a net-shaped structure, so that the mechanical property of the coating is improved; wherein tin antimony oxide has good shielding property on near-infrared light, so that the glass is more energy-saving; wherein anti-ultraviolet agent molecules can improve the anti-ultraviolet performance and certain hydrophobicity of the coating and are high in migration resistance; in conclusion, the prepared coating is good in hydrophobicity, high in mechanical strength and high in infrared shielding rate, also has stable and efficient anti-ultraviolet performance, and has important application value in the technical field of building glass.

Description

Technical Field

[0001] The present invention belongs to the technical field of architectural glass, and in particular relates to a method for preparing a transparent super-hydrophobic coating. Background Art

[0002] Many biological surfaces in nature have special surface wetting behaviors. Researchers have found that when water droplets are dropped on the upper surface of lotus leaves, the upper surface of rice leaves, and the feet of water striders, a contact angle greater than 150° can be obtained. This surface that exhibits super-anti-wetting properties to water droplets is called a superhydrophobic surface. Through electron microscopy, it can be found that the surface of the lotus leaf is covered with micron-scale papillary structures, and these papillae are covered with nano-scale waxy substances. This multi-level rough structure combined with low surface energy materials makes the water droplets on the lotus leaf surface appear nearly spherical and can roll easily, thereby carrying away dust and other pollutants and achieving a self-cleaning effect. Inspired by this, the research and preparation of functional materials with superhydrophobic properties has attracted widespread attention in scientific research and industrial applications in recent years.

[0003] With the acceleration of global urbanization and the influx of people into cities, land supply is becoming saturated. The construction of high-rise buildings can accommodate more people, office space, or commercial facilities on limited land, thereby improving land use efficiency. The increasing number of high-rise buildings also presents some problems. The glass of high-rise buildings, exposed to the outdoors and constantly attacked by rain, easily accumulates dust on its surface, making it difficult to clean. Using superhydrophobic coatings can reduce cleaning frequency, lower cleaning costs, and avoid the dangers of high-altitude work, offering great potential for application in the field of architectural glass.

[0004] Another issue worth considering is the coating's service life. Since high-rise building glass is used outdoors and is exposed to long-term UV radiation, strict requirements are placed on the coating's resistance to UV aging. Therefore, there is an urgent need to develop a transparent coating that combines superhydrophobicity with UV resistance to meet the increasing demands of high-rise building glass technology. Summary of the Invention

[0005] The purpose of the present invention is to overcome the defects of the prior art and provide a method for preparing a transparent super-hydrophobic coating.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A method for preparing a transparent super-hydrophobic coating comprises the following steps:

[0008] Add antimony tin oxide and nano-silica into a solvent, and ultrasonically disperse for 10 - 20 min to obtain a dispersion. Add the dispersion, curing agent, ultraviolet-resistant agent, vinyl-terminated polydimethylsiloxane, and hydrogen-containing silicone oil into a reaction kettle. After mechanical stirring for 10 - 15 min, a hydrophobic coating is obtained. Spray the hydrophobic coating on a glass substrate with a spray gun and dry and cure it at 100 - 120 °C to obtain a transparent superhydrophobic coating.

[0009] Furthermore, the raw materials are as follows by weight: 4 - 6 parts of antimony tin oxide, 10 - 15 parts of nano-silica, 80 - 100 parts of solvent, 0.3 - 0.5 parts of curing agent, 3 - 9 parts of ultraviolet-resistant agent, 53 - 65 parts of vinyl-terminated polydimethylsiloxane, and 26 - 38 parts of hydrogen-containing silicone oil.

[0010] Furthermore, the solvent is one of acetone, butyl acetate, and ethyl acetate.

[0011] Furthermore, the curing agent is a platinum-based catalyst.

[0012] Furthermore, the ultraviolet-resistant agent is prepared through the following steps:

[0013] Step A1: Weigh methylvinyldichlorosilane and 2-aminobenzotriazole as reaction raw materials, and add them together with the solvent N,N-dimethylformamide and the catalyst potassium carbonate into a three-necked flask equipped with a thermometer and an electromagnetic stirrer. After stirring and mixing evenly, heat the device. When the temperature reaches 65 °C, maintain this temperature and stir the reaction for 7 h. After the reaction is completed, filter, remove the solvent by vacuum distillation, wash with anhydrous ethanol multiple times, and dry under vacuum to obtain a reaction intermediate.

[0014] The reaction principle is that under the catalysis of potassium carbonate, methylvinyldichlorosilane and 2-aminobenzotriazole undergo a nucleophilic substitution reaction, and the molar ratio of the two is controlled at 1:1 (methylvinyldichlorosilane is slightly in excess). The specific reaction process is as follows:

[0015]

[0016] Step A2: Weigh the reaction intermediate and 2,4-dihydroxybenzophenone as reaction raw materials, and add them together with the solvent N,N-dimethylformamide and the catalyst sodium carbonate solution into a three-necked flask equipped with a thermometer and an electromagnetic stirrer. After stirring and mixing evenly, heat the device. When the temperature reaches 70 °C, maintain this temperature and stir the reaction for 8 h. After the reaction is completed, filter, remove part of the solvent by vacuum distillation, and then purify by silica gel column chromatography (the eluent is benzene and ethyl acetate, and the volume ratio of the two is 3:1). Rotate and evaporate to remove the eluent to obtain the ultraviolet-resistant agent.

[0017] The reaction principle is that the phenolic hydroxyl groups of 2,4-dihydroxybenzophenone have weak acidity. However, the phenolic hydroxyl group at the 2-position can form a stable intramolecular hydrogen bond with the ketone carbonyl group, which is not conducive to the attack of nucleophiles. While the phenolic hydroxyl group at the 4-position has stronger acidity and can react with sodium carbonate to form a phenoxide anion, which then reacts with the chloro group on the reaction intermediate molecule. The specific reaction process is as follows:

[0018]

[0019] The anti-ultraviolet agent is prepared through two-step reactions. The anti-ultraviolet agent molecule contains benzophenone and benzotriazole anti-ultraviolet groups. Among them, benzophenone, as a classic type of ultraviolet absorber, its anti-ultraviolet function mainly depends on the unique conjugated ketone group system in the molecular structure. This type of compound effectively absorbs and converts ultraviolet light energy through the synergistic effect of photophysical and photochemical processes, thereby protecting the material from photodegradation and improving the anti-ultraviolet performance of the coating. The structure of benzotriazole is unique, with the benzene ring fused to the triazole ring, endowing it with unique anti-ultraviolet and photo-stabilization functions. It can be in a different anti-ultraviolet range from benzophenone, and the two can play a synergistic role, greatly improving the anti-ultraviolet performance of the coating. In addition, the anti-ultraviolet agent contains multiple hydrophobic groups, which can also improve the hydrophobic performance of the coating to a certain extent. Finally, one end of the anti-ultraviolet agent contains an alkenyl group, which can participate in the curing reaction, improving the migration resistance of the small molecule anti-ultraviolet agent.

[0020] Further, in step A1, the dosage ratio of methylvinyldichlorosilane, 2-aminobenzotriazole, N,N-dimethylformamide, and potassium carbonate is 13.4 g: 15.2 g: 100 mL: 13.8 g.

[0021] Further, in step A2, the dosage ratio of the reaction intermediate, 2,4-dihydroxybenzophenone, N,N-dimethylformamide, and sodium carbonate solution is 23.8 g: 21.4 g: 120 mL: 30 mL.

[0022] Advantages of the present invention:

[0023] 1. The transparent superhydrophobic coating prepared by the present invention uses vinyl-terminated polydimethylsiloxane and hydrogen-containing silicone oil as the main raw materials. The two can undergo crosslinking and curing under the action of a platinum-based catalyst to form a network structure, improving the mechanical properties of the coating;

[0024] 2. Antimony tin oxide is added to the raw materials. It is a transparent conductive oxide with not only high visible light transmittance but also good shielding property for near-infrared light, making the glass more energy-efficient;

[0025] 3. The prepared anti-ultraviolet agent molecule contains a variety of functional groups, which can improve the anti-ultraviolet performance and certain hydrophobicity of the coating. Moreover, because one end of it contains an alkenyl group, it can participate in the curing reaction, thereby improving the migration resistance of the small molecule anti-ultraviolet agent.

[0026] In summary, the superhydrophobic coating prepared by the present invention has good hydrophobicity, high mechanical strength, strong infrared shielding rate, and also has stable and efficient anti-ultraviolet performance, and has important application value in the field of architectural glass technology. Detailed implementation manners

[0027] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0028] Example 1

[0029] Preparation of anti-ultraviolet agent:

[0030] Step A1: Weigh 13.4 g of methylvinyldichlorosilane and 15.2 g of 2-aminobenzotriazole as reaction raw materials, and add them to a three-necked flask equipped with a thermometer and an electromagnetic stirrer together with 100 mL of the solvent N,N-dimethylformamide and 13.8 g of the catalyst potassium carbonate. After stirring and mixing evenly, heat the device. When the temperature reaches 65 °C, maintain this temperature and stir the reaction for 7 h. After the reaction is completed, filter, remove the solvent by reduced pressure distillation, wash with absolute ethanol multiple times, and dry under vacuum to obtain a reaction intermediate.

[0031] Step A2: Weigh 23.8 g of the reaction intermediate and 21.4 g of 2,4-dihydroxybenzophenone as reaction raw materials, and add them to a three-necked flask equipped with a thermometer and an electromagnetic stirrer together with 120 mL of the solvent N,N-dimethylformamide and 30 mL of the catalyst sodium carbonate solution. After stirring and mixing evenly, heat the device. When the temperature reaches 70 °C, maintain this temperature and stir the reaction for 8 h. After the reaction is completed, filter, remove part of the solvent by reduced pressure distillation, and then purify by silica gel column chromatography (the eluent is benzene and ethyl acetate, and the volume ratio of the two is 3:1). Rotate and evaporate to remove the eluent to obtain the anti-ultraviolet agent.

[0032] Example 2

[0033] Preparation of anti-ultraviolet agent:

[0034] Step A1: Weigh 26.8 g of methylvinyldichlorosilane and 30.4 g of 2-aminobenzotriazole as reaction raw materials, and add them together with 200 mL of the solvent N,N-dimethylformamide and 27.6 g of the catalyst potassium carbonate into a three-necked flask equipped with a thermometer and an electromagnetic stirrer. After stirring and mixing evenly, heat the device. When the temperature reaches 65 °C, maintain this temperature and stir for 7 h. After the reaction is completed, filter, remove the solvent by reduced pressure distillation, wash with absolute ethanol multiple times, and dry under vacuum to obtain the reaction intermediate;

[0035] Step A2: Weigh 47.6 g of the reaction intermediate and 42.8 g of 2,4-dihydroxybenzophenone as reaction raw materials, and add them together with 240 mL of the solvent N,N-dimethylformamide and 60 mL of the catalyst sodium carbonate solution into a three-necked flask equipped with a thermometer and an electromagnetic stirrer. After stirring and mixing evenly, heat the device. When the temperature reaches 70 °C, maintain this temperature and stir for 8 h. After the reaction is completed, filter, remove part of the solvent by reduced pressure distillation, and then purify by silica gel column chromatography (the eluent is benzene and ethyl acetate, and the volume ratio of the two is 3:1). Rotate and evaporate to remove the eluent to obtain the ultraviolet absorber.

[0036] Example Three

[0037] Add 4 g of antimony tin oxide and 10 g of nano-silica into 80 g of acetone, and ultrasonically disperse for 10 min to obtain a dispersion. Add the dispersion, 0.3 g of chloroplatinic acid, 3 g of the ultraviolet absorber prepared in Example One, 53 g of vinyl-terminated polydimethylsiloxane, and 26 g of hydrogen-containing silicone oil into the reaction kettle. After mechanical stirring for 10 min, a hydrophobic coating is obtained. Spray the hydrophobic coating on the glass substrate with a spray gun and dry and cure at 100 °C to obtain a transparent superhydrophobic coating.

[0038] Example Four

[0039] Add 5 g of antimony tin oxide and 12 g of nano-silica into 90 g of butyl acetate, and ultrasonically disperse for 20 min to obtain a dispersion. Add the dispersion, 0.4 g of chloroplatinic acid, 6 g of the ultraviolet absorber prepared in Example One, 59 g of vinyl-terminated polydimethylsiloxane, and 32 g of hydrogen-containing silicone oil into the reaction kettle. After mechanical stirring for 15 min, a hydrophobic coating is obtained. Spray the hydrophobic coating on the glass substrate with a spray gun and dry and cure at 110 °C to obtain a transparent superhydrophobic coating.

[0040] Example Five

[0041] 6 g of antimony tin oxide and 15 g of nano - silica were added to 100 g of ethyl acetate and ultrasonically dispersed for 20 min to obtain a dispersion. The dispersion, 0.5 g of chloroplatinic acid, 9 g of the ultraviolet - resistant agent prepared in Example 1, 65 g of vinyl - terminated polydimethylsiloxane, and 38 g of hydrogen - containing silicone oil were added to a reaction kettle. After mechanical stirring for 15 min, a hydrophobic coating was obtained. The hydrophobic coating was sprayed on a glass substrate with a spray gun and dried and cured at 120 °C to obtain a transparent super - hydrophobic coating.

[0042] Comparative Example 1

[0043] During the preparation process of Example 5, only the ultraviolet - resistant agent was replaced with an equal amount of commercially available ultraviolet - resistant agent, and the other conditions remained unchanged to obtain a coating.

[0044] Comparative Example 2

[0045] A commercially available super - hydrophobic coating was used.

[0046] The transmittance was measured according to the national standard GB / T 2410 - 2008 "Determination of Transmittance and Haze of Transparent Plastics".

[0047] According to the national standard GB / T 2680 - 2021, the infrared barrier rate and ultraviolet absorption rate of the test sample were measured.

[0048] The contact angle of the test sample was measured with a contact angle measuring instrument.

[0049] The measured results are shown in the following table:

[0050]

[0051] As can be seen from the above table, the hydrophobicity, infrared shielding rate, and ultraviolet - resistant performance of the coatings prepared in the examples of the present invention are higher than those of the comparative examples, and the transmittance is good. Therefore, the present invention has important application value in the technical field of architectural glass.

[0052] In the description of the specification, the description with reference to terms such as "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above - mentioned terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0053] The above content is only an example and explanation of the present invention. Those skilled in the art of the present technology can make various modifications or supplements to the described specific embodiments or use similar methods for substitution, which should all fall within the protection scope of the present invention.

Claims

1. A preparation method of a transparent superhydrophobic coating, characterized in that, It includes the following steps: Add stannic antimonate oxide and nano-silica into a solvent, and perform ultrasonic dispersion to obtain a dispersion liquid. Add the dispersion liquid, curing agent, ultraviolet-resistant agent, vinyl-terminated polydimethylsiloxane, and hydrogen-containing silicone oil into a reaction kettle. After mechanical stirring, a hydrophobic coating is obtained. Spray the hydrophobic coating on a glass substrate and dry and cure it to obtain a transparent superhydrophobic coating.

2. The preparation method of a transparent superhydrophobic coating according to claim 1, wherein The amounts of each raw material are as follows by weight: 4 - 6 parts of stannic antimonate oxide, 10 - 15 parts of nano-silica, 80 - 100 parts of solvent, 0.3 - 0.5 part of curing agent, 3 - 9 parts of ultraviolet-resistant agent, 53 - 65 parts of vinyl-terminated polydimethylsiloxane, and 26 - 38 parts of hydrogen-containing silicone oil.

3. The preparation method of a transparent superhydrophobic coating according to claim 1, characterized in that, The solvent is one of acetone, butyl acetate, and ethyl acetate.

4. The preparation method of a transparent superhydrophobic coating according to claim 1, characterized in that, The curing agent is a platinum-based catalyst.

5. The preparation method of a transparent superhydrophobic coating according to claim 1, characterized in that, The ultraviolet-resistant agent is prepared through the following steps: Step A1: Add methylvinyldichlorosilane, 2-aminobenzotriazole, N,N-dimethylformamide, and potassium carbonate into a flask, stir and mix them, heat to 65 °C, and stir and react for 7 h. After the reaction is completed, a reaction intermediate is obtained. Step A2: Add the reaction intermediate, 2,4-dihydroxybenzophenone, N,N-dimethylformamide, and sodium carbonate solution into a flask, stir and mix them, heat to 70 °C, and stir and react for 8 h. After the reaction is completed, an ultraviolet-resistant agent is obtained.

6. The preparation method of a transparent superhydrophobic coating according to claim 5, characterized in that, In Step A1, the dosage ratio of methylvinyldichlorosilane, 2-aminobenzotriazole, N,N-dimethylformamide, and potassium carbonate is 13.4 g:15.2 g:100 mL:13.8 g.

7. A method for preparing a transparent superhydrophobic coating according to claim 5, characterized in that, In Step A2, the dosage ratio of the reaction intermediate, 2,4-dihydroxybenzophenone, N,N-dimethylformamide, and sodium carbonate solution is 23.8 g:21.4 g:120 mL:30 mL.

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