A highly weather-resistant self-cleaning nano-silicon coating and its preparation process

Abstract

The invention discloses a highly weather-resistant self-cleaning nano-silicon coating and a preparation process thereof, and relates to the technical field of coatings. In order to improve the stain resistance of the coating, the invention prepares a moisture-curable nano-silicon polyester resin with a strong self-cleaning effect. The invention first uses 3-amino-4-fluorobenzoic acid, tetramethoxysilane and the like as raw materials for reaction, and generates a nano-silicon resin polymer containing nano-silicon dioxide by controlling the reaction conditions. The presence of nano-silicon dioxide can effectively improve the micro-nano structure of the coating, and control the contact angle between water droplets and the coating surface. Then, the obtained nano-silicon resin polymer is reacted with isocyanate substances and the like, so that the final synthetic resin contains some free isocyanate groups, and these isocyanate groups can be combined with water molecules in the air, thereby realizing the effect of moisture curing, effectively reducing the construction difficulty of the coating, and can be used for the protection and self-cleaning maintenance of building exterior walls.

Description

Technical Field

[0001] The invention relates to the technical field of coatings, in particular to a highly weather-resistant self-cleaning nano silicon coating and a preparation process thereof. Background Art

[0002] The anti-fouling and cleaning issues of building exterior walls have always been a hot research topic, especially for the exterior walls of buildings in public places, which are often faced with various problems such as automobile exhaust pollution and graffiti. Often, the original paint has to be refurbished before its service life has expired, causing a huge waste of human and material resources. Summary of the invention

[0003] The purpose of the present invention is to provide a highly weather-resistant self-cleaning nano-silicon coating and a preparation process thereof, so as to solve the problems raised in the prior art.

[0004] To achieve the above object, the present invention provides the following technical solution: a preparation process of a highly weather-resistant self-cleaning nano-silicon coating, comprising the following steps:

[0005] S1. Preparation of nano-silicon polyester resin;

[0006] The pentaerythritol and ε-caprolactone are mixed, heated to 125-130°C, stannous octoate is added, stirred for reaction for 6-12 hours, cooled to room temperature, and the nano-silicone resin polymer is added thereto, and the mixture is mixed for 35-45 minutes, and isophorone diisocyanate, a polymerization inhibitor and a reaction solvent are added thereto, and the mixture is heated to 55-70°C, and the mixture is stirred for reaction for 2-4 hours, and the excess reaction solvent is removed by rotary evaporation to obtain a nano-silicone polyester resin;

[0007] S2. Preparation of highly weather-resistant self-cleaning nano-silicon coating;

[0008] The nano-silicon polyester resin is mixed with a solvent, and a weather-resistant antioxidant, a defoaming agent, a thixotropic agent, an abrasion-resistant additive, a nano-additive and a leveling agent are added thereto. After high-speed stirring and mixing for 15-45 minutes, vacuum defoaming is performed to obtain a highly weather-resistant self-cleaning nano-silicon coating.

[0009] Furthermore, in step S1, the preparation method of the nano silicone polymer is:

[0010] A. Disperse 3-amino-4-fluorobenzoic acid in ether, heat to 45-70°C, stir until mixed evenly, and cool to room temperature to obtain a 3-amino-4-fluorobenzoic acid dispersion;

[0011] Disperse ethyl trifluoroacetate in anhydrous ether, cool to constant temperature in an ice-water bath, stir for 15-30 minutes, slowly drop 3-amino-4-fluorobenzoic acid dispersion therein, control the temperature of the reaction system to be 0-4°C during the dropwise addition, continue stirring the reaction for 2-8 hours after the dropwise addition, and remove excess solvent by rotary evaporation to obtain an amino-protected fluorobenzoic acid intermediate;

[0012] B. Disperse the amino-protected fluorobenzoic acid intermediate into pure DMF, protect under nitrogen atmosphere, mix evenly at room temperature, add benzenesulfonic acid, continue mixing for 15-30 minutes, and then slowly drop it into tetramethoxysilane. During the dropwise addition, control the reaction system temperature to 72-78°C, and the dropwise addition time is 1-4 hours. After the dropwise addition is completed, continue stirring the reaction for 0.5-1 hour, and remove the excess solvent by rotary evaporation to obtain the methoxysilane intermediate;

[0013] C. Disperse ethyl orthosilicate in ethyl acetate, heat to 75-80°C, mix well, add hydrochloric acid to adjust the pH to 3.8-4.2, continue to add deionized water, stir and react for 3-4 hours to obtain ethyl orthosilicate dispersion;

[0014] The methoxysilane intermediate is dispersed in anhydrous ethanol, and after ultrasonic vibration dispersion for 3-4 hours, it is added dropwise into the ethyl orthosilicate dispersion for 2-4 hours. After the addition is completed, the temperature is continued to rise to 78-80°C, and the reaction is stirred for 8-12 hours. After the excess solvent is removed by rotary evaporation, deionized water is added again, and hydrochloric acid is added dropwise to adjust the pH to 3-3.5. After stirring and reacting for 1 hour, the excess solvent is removed by rotary evaporation, and the dried product is washed 1-3 times with deionized water at a temperature of 0-4°C, and vacuum dried to constant weight to obtain a nano silicone resin polymer.

[0015] Furthermore, in step S1, the nano-silicone polyester resin is composed of 8-10 parts of pentaerythritol, 52-70 parts of ε-caprolactone, 0.1-0.3 parts of stannous octoate, 10-25 parts of nano-silicone resin polymer, 14-18 parts of isophorone diisocyanate, 0.1-0.3 parts of inhibitor and 10-15 parts of reaction solvent in parts by weight.

[0016] Furthermore, in step S1, the polymerization inhibitor is p-hydroxyanisole; and the reaction solvent is DMF.

[0017] Furthermore, in step S2, the highly weather-resistant self-cleaning nano-silicon coating is composed, by weight, of 50-60 parts of nano-silicon polyester resin, 30-40 parts of solvent, 0.5-1 part of weather-resistant antioxidant, 0.2-0.5 part of defoaming agent, 0.8-1.5 parts of thixotropic agent, 1-3 parts of wear-resistant additive, 4-5 parts of nano additive and 0.2-0.3 parts of leveling agent.

[0018] Furthermore, in step S2, the solvent is a mixed solvent of tetraethyl orthosilicate and octamethylcyclotetrasiloxane in a volume ratio of 7:3; the weather-resistant antioxidant is antioxidant 1010; the defoaming agent is a silicone defoaming agent; the thixotropic agent is talcum powder; the wear-resistant additive is graphene; the nano additive is nano silicon dioxide; and the leveling agent is BYK333 leveling agent.

[0019] Furthermore, in step A, the mass ratio of 3-amino-4-fluorobenzoic acid to ethyl trifluoroacetate is 1:(0.9-1) by weight.

[0020] Furthermore, in step B, the mass ratio of the amino-protected fluorobenzoic acid intermediate, benzenesulfonic acid, and tetramethoxysilane is 1:(0.04-0.1):(0.4-1).

[0021] Furthermore, in step C, the mass ratio of the ethyl orthosilicate to the methoxysilane intermediate is (1.1-2.1):1.

[0022] A highly weather-resistant self-cleaning nano-silicon coating is prepared by the method.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] In order to improve the anti-fouling ability of the coating, the present invention prepares a nano-silicon polyester resin that can be cured by moisture and has a strong self-cleaning effect, and by adding various additives thereto, the wear resistance and weather resistance of the resin coating are improved, thereby achieving the durability of the coating;

[0025] The present invention first uses 3-amino-4-fluorobenzoic acid as a raw material, and uses ethyl trifluoroacetate to react with it, thereby protecting the amino group in the 3-amino-4-fluorobenzoic acid, and then reacts it with tetramethoxysilane containing methoxy groups, and controls the reaction conditions so that the carboxyl group in the 3-amino-4-fluorobenzoic acid reacts with part of the methoxy groups in the tetramethoxysilane, thereby preparing a methoxysilane intermediate containing a methoxy group and a fluorine element; on this basis, the present invention further uses ethyl orthosilicate to hydrolyze in an acidic environment, thereby generating a nano-silica sol containing a large amount of hydroxyl groups on the surface, and then mixes the methoxysilane intermediates and hydrolyzes them together, thereby obtaining a nano-silicon resin polymer containing nano-silica; the presence of nano-silica can effectively improve the micro-nano structure of the coating, thereby generating a nano-scale rough structure, effectively controlling the contact angle between a water droplet and the coating surface, and the fluorine element introduced in this process can also further enhance the hydrophobicity of the material, improve the coating's tolerance to water vapor, and avoid coating peeling caused by water vapor infiltration during use;

[0026] In this process, the hydrochloric acid added also adjusts the pH value, so that the amino groups protected by ethyl trifluoroacetate are released, thereby introducing some amino groups on the surface of the generated nano-silicon, which can participate in the subsequent synthesis of nano-silicon resin.

[0027] Afterwards, the obtained nano-silicone resin polymer is reacted with pentaerythritol and isocyanate substances. By controlling the reaction conditions, the final synthetic resin contains some free isocyanate groups. These isocyanate groups can combine with water molecules in the air to achieve moisture curing, which effectively reduces the construction difficulty of the coating prepared by the present invention and can be effectively used for the protection and self-cleaning maintenance of building exterior walls. DETAILED DESCRIPTION

[0028] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of the present invention.

[0029] The defoamer used in this application is Tego Foamex 842 defoamer; the graphene used is flake graphene with a particle size of 3000 mesh; the nano-silica used is TSP-L60 hydrophobic nano-scale silica; Example

[0030] A preparation process of a highly weather-resistant self-cleaning nano-silicon coating comprises the following steps:

[0031] S1. Preparation of nano-silicon polyester resin;

[0032] By weight, 8 parts of pentaerythritol and 52 parts of ε-caprolactone were mixed, the temperature was raised to 125-130° C., 0.1 parts of stannous octoate were added, the mixture was stirred for reaction for 10 hours, and then the mixture was cooled to room temperature, 10 parts of nano-silicone resin polymer were added thereto, the mixture was mixed for 35 minutes, 14 parts of isophorone diisocyanate, 0.1 parts of p-hydroxyanisole and 10 parts of DMF were added, the temperature was raised to 70° C., the mixture was stirred for reaction for 3 hours, and the excess reaction solvent was removed by rotary evaporation to obtain a nano-silicone polyester resin;

[0033] Wherein, the preparation method of the nano silicone resin polymer is:

[0034] A. Disperse 1 part of 3-amino-4-fluorobenzoic acid in ether by weight, heat to 58°C, stir until mixed evenly, and cool to room temperature to obtain a 3-amino-4-fluorobenzoic acid dispersion;

[0035] Disperse 0.95 parts of ethyl trifluoroacetate in anhydrous ether, cool to constant temperature in an ice-water bath, stir for 25 minutes, slowly drop 3-amino-4-fluorobenzoic acid dispersion therein, control the temperature of the reaction system at 2-4°C during the dropwise addition, continue stirring the reaction for 6 hours after the dropwise addition, and remove excess solvent by rotary evaporation to obtain an amino-protected fluorobenzoic acid intermediate;

[0036] B. Disperse 1 part of amino-protected fluorobenzoic acid intermediate into pure DMF by weight, protect under nitrogen atmosphere, mix evenly at room temperature, add 0.08 part of benzenesulfonic acid, continue mixing for 25 minutes, and then slowly drop it into 1 part of tetramethoxysilane. During the dropwise addition, control the temperature of the reaction system to 72-78°C, and the dropwise addition time is 3 hours. After the dropwise addition is completed, continue stirring the reaction for 1 hour, and remove the excess solvent by rotary evaporation to obtain the methoxysilane intermediate;

[0037] C. Disperse 1.1 parts of tetraethyl orthosilicate in ethyl acetate by weight, heat to 78°C, mix evenly, add hydrochloric acid to adjust the pH to 4, continue to add deionized water, stir and react for 4 hours to obtain a tetraethyl orthosilicate dispersion;

[0038] Disperse 1 part of the methoxysilane intermediate in anhydrous ethanol, disperse it by ultrasonic vibration for 4 hours, and then add it dropwise to the ethyl orthosilicate dispersion for 3 hours. After the addition is completed, continue to heat up to 80°C, stir and react for 10 hours, remove excess solvent by rotary evaporation, add deionized water again, and add hydrochloric acid to adjust the pH to 3. After stirring and reacting for 1 hour, remove excess solvent by rotary evaporation, wash and dry the product twice with deionized water at a temperature of 0-4°C, and vacuum dry to constant weight to obtain a nano silicone resin polymer;

[0039] S2. Preparation of highly weather-resistant self-cleaning nano-silicon coating;

[0040] By weight, 50 parts of nano-silicone polyester resin were mixed with 40 parts of solvent, and 0.8 parts of antioxidant 1010, 0.3 parts of silicone defoaming agent, 0.8 parts of talc thixotropic agent, 2 parts of graphene, 4 parts of nano-additives and 0.3 parts of BYK333 leveling agent were added thereto. After high-speed stirring and mixing for 30 minutes, vacuum defoaming was performed to obtain a highly weather-resistant self-cleaning nano-silicone coating. Example

[0041] A preparation process of a highly weather-resistant self-cleaning nano-silicon coating comprises the following steps:

[0042] Compared with Example 1, this example reduces the amount of tetramethoxysilane added in step B;

[0043] S1. Preparation of nano-silicon polyester resin;

[0044] By weight, 8 parts of pentaerythritol and 52 parts of ε-caprolactone were mixed, the temperature was raised to 125-130° C., 0.1 parts of stannous octoate were added, the mixture was stirred for reaction for 10 hours, and then the mixture was cooled to room temperature, 10 parts of nano-silicone resin polymer were added thereto, the mixture was mixed for 35 minutes, 14 parts of isophorone diisocyanate, 0.1 parts of p-hydroxyanisole and 10 parts of DMF were added, the temperature was raised to 70° C., the mixture was stirred for reaction for 3 hours, and the excess reaction solvent was removed by rotary evaporation to obtain a nano-silicone polyester resin;

[0045] Wherein, the preparation method of the nano silicone resin polymer is:

[0046] A. Disperse 1 part of 3-amino-4-fluorobenzoic acid in ether by weight, heat to 58°C, stir until mixed evenly, and cool to room temperature to obtain a 3-amino-4-fluorobenzoic acid dispersion;

[0047] Disperse 0.95 parts of ethyl trifluoroacetate in anhydrous ether, cool to constant temperature in an ice-water bath, stir for 25 minutes, slowly drop 3-amino-4-fluorobenzoic acid dispersion therein, control the temperature of the reaction system at 2-4°C during the dropwise addition, continue stirring the reaction for 6 hours after the dropwise addition, and remove excess solvent by rotary evaporation to obtain an amino-protected fluorobenzoic acid intermediate;

[0048] B. Disperse 1 part of amino-protected fluorobenzoic acid intermediate into pure DMF by weight, protect under nitrogen atmosphere, mix evenly at room temperature, add 0.08 part of benzenesulfonic acid, continue mixing for 25 minutes, and then slowly drop it into 0.4 part of tetramethoxysilane. During the dropwise addition, control the temperature of the reaction system to 72-78°C, and the dropwise addition time is 3 hours. After the dropwise addition is completed, continue stirring the reaction for 1 hour, and remove the excess solvent by rotary evaporation to obtain the methoxysilane intermediate;

[0049] C. Disperse 1.1 parts of tetraethyl orthosilicate in ethyl acetate by weight, heat to 78°C, mix evenly, add hydrochloric acid to adjust the pH to 4, continue to add deionized water, stir and react for 4 hours to obtain a tetraethyl orthosilicate dispersion;

[0050] Disperse 1 part of the methoxysilane intermediate in anhydrous ethanol, disperse it by ultrasonic vibration for 4 hours, and then add it dropwise to the ethyl orthosilicate dispersion for 3 hours. After the addition is completed, continue to heat up to 80°C, stir and react for 10 hours, remove excess solvent by rotary evaporation, add deionized water again, and add hydrochloric acid to adjust the pH to 3. After stirring and reacting for 1 hour, remove excess solvent by rotary evaporation, wash and dry the product twice with deionized water at a temperature of 0-4°C, and vacuum dry to constant weight to obtain a nano silicone resin polymer;

[0051] S2. Preparation of highly weather-resistant self-cleaning nano-silicon coating;

[0052] By weight, 50 parts of nano-silicone polyester resin were mixed with 40 parts of solvent, and 0.8 parts of antioxidant 1010, 0.3 parts of silicone defoaming agent, 0.8 parts of talc thixotropic agent, 2 parts of graphene, 4 parts of nano-additives and 0.3 parts of BYK333 leveling agent were added thereto. After high-speed stirring and mixing for 30 minutes, vacuum defoaming was performed to obtain a highly weather-resistant self-cleaning nano-silicone coating. Example

[0053] A preparation process of a highly weather-resistant self-cleaning nano-silicon coating comprises the following steps:

[0054] Compared with Example 1, the amount of tetraethyl orthosilicate added in this example is increased;

[0055] S1. Preparation of nano-silicon polyester resin;

[0056] By weight, 8 parts of pentaerythritol and 52 parts of ε-caprolactone were mixed, the temperature was raised to 125-130° C., 0.1 parts of stannous octoate were added, the mixture was stirred for reaction for 10 hours, and then the mixture was cooled to room temperature, 10 parts of nano-silicone resin polymer were added thereto, the mixture was mixed for 35 minutes, 14 parts of isophorone diisocyanate, 0.1 parts of p-hydroxyanisole and 10 parts of DMF were added, the temperature was raised to 70° C., the mixture was stirred for reaction for 3 hours, and the excess reaction solvent was removed by rotary evaporation to obtain a nano-silicone polyester resin;

[0057] Wherein, the preparation method of the nano silicone resin polymer is:

[0058] A. Disperse 1 part of 3-amino-4-fluorobenzoic acid in ether by weight, heat to 58°C, stir until mixed evenly, and cool to room temperature to obtain a 3-amino-4-fluorobenzoic acid dispersion;

[0059] Disperse 0.95 parts of ethyl trifluoroacetate in anhydrous ether, cool to constant temperature in an ice-water bath, stir for 25 minutes, slowly drop 3-amino-4-fluorobenzoic acid dispersion therein, control the temperature of the reaction system at 2-4°C during the dropwise addition, continue stirring the reaction for 6 hours after the dropwise addition, and remove excess solvent by rotary evaporation to obtain an amino-protected fluorobenzoic acid intermediate;

[0060] B. Disperse 1 part of amino-protected fluorobenzoic acid intermediate into pure DMF by weight, protect under nitrogen atmosphere, mix evenly at room temperature, add 0.08 part of benzenesulfonic acid, continue mixing for 25 minutes, and then slowly drop it into 1 part of tetramethoxysilane. During the dropwise addition, control the temperature of the reaction system to 72-78°C, and the dropwise addition time is 3 hours. After the dropwise addition is completed, continue stirring the reaction for 1 hour, and remove the excess solvent by rotary evaporation to obtain the methoxysilane intermediate;

[0061] C. Disperse 2.1 parts of tetraethyl orthosilicate in ethyl acetate by weight, heat to 78°C, mix evenly, add hydrochloric acid to adjust the pH to 4, continue to add deionized water, stir and react for 4 hours to obtain a tetraethyl orthosilicate dispersion;

[0062] Disperse 1 part of the methoxysilane intermediate in anhydrous ethanol, disperse it by ultrasonic vibration for 4 hours, and then add it dropwise to the ethyl orthosilicate dispersion for 3 hours. After the addition is completed, continue to heat up to 80°C, stir and react for 10 hours, remove excess solvent by rotary evaporation, add deionized water again, and add hydrochloric acid to adjust the pH to 3. After stirring and reacting for 1 hour, remove excess solvent by rotary evaporation, wash and dry the product twice with deionized water at a temperature of 0-4°C, and vacuum dry to constant weight to obtain a nano silicone resin polymer;

[0063] S2. Preparation of highly weather-resistant self-cleaning nano-silicon coating;

[0064] By weight, 50 parts of nano-silicone polyester resin were mixed with 40 parts of solvent, and 0.8 parts of antioxidant 1010, 0.3 parts of silicone defoaming agent, 0.8 parts of talc thixotropic agent, 2 parts of graphene, 4 parts of nano-additives and 0.3 parts of BYK333 leveling agent were added thereto. After high-speed stirring and mixing for 30 minutes, vacuum defoaming was performed to obtain a highly weather-resistant self-cleaning nano-silicone coating. Example

[0065] A preparation process of a highly weather-resistant self-cleaning nano-silicon coating comprises the following steps:

[0066] Compared with Example 1, this example increases the amount of nano-silicone resin polymer added in step S2;

[0067] S1. Preparation of nano-silicon polyester resin;

[0068] By weight, 8 parts of pentaerythritol and 52 parts of ε-caprolactone were mixed, heated to 125-130° C., 0.1 parts of stannous octoate were added, stirred and reacted for 10 hours, cooled to room temperature, 25 parts of nano-silicone resin polymer were added thereto, and the mixture was mixed for 35 minutes, 14 parts of isophorone diisocyanate, 0.1 parts of p-hydroxyanisole and 10 parts of DMF were added, the mixture was heated to 70° C., the mixture was stirred and reacted for 3 hours, and the excess reaction solvent was removed by rotary evaporation to obtain a nano-silicone polyester resin;

[0069] Wherein, the preparation method of the nano silicone resin polymer is:

[0070] A. Disperse 1 part of 3-amino-4-fluorobenzoic acid in ether by weight, heat to 58°C, stir until mixed evenly, and cool to room temperature to obtain a 3-amino-4-fluorobenzoic acid dispersion;

[0071] Disperse 0.95 parts of ethyl trifluoroacetate in anhydrous ether, cool to constant temperature in an ice-water bath, stir for 25 minutes, slowly drop 3-amino-4-fluorobenzoic acid dispersion therein, control the temperature of the reaction system at 2-4°C during the dropwise addition, continue stirring the reaction for 6 hours after the dropwise addition, and remove excess solvent by rotary evaporation to obtain an amino-protected fluorobenzoic acid intermediate;

[0072] B. Disperse 1 part of amino-protected fluorobenzoic acid intermediate into pure DMF by weight, protect under nitrogen atmosphere, mix evenly at room temperature, add 0.08 part of benzenesulfonic acid, continue mixing for 25 minutes, and then slowly drop it into 1 part of tetramethoxysilane. During the dropwise addition, control the temperature of the reaction system to 72-78°C, and the dropwise addition time is 3 hours. After the dropwise addition is completed, continue stirring the reaction for 1 hour, and remove the excess solvent by rotary evaporation to obtain the methoxysilane intermediate;

[0073] C. Disperse 1.1 parts of tetraethyl orthosilicate in ethyl acetate by weight, heat to 78°C, mix evenly, add hydrochloric acid to adjust the pH to 4, continue to add deionized water, stir and react for 4 hours to obtain a tetraethyl orthosilicate dispersion;

[0074] Disperse 1 part of the methoxysilane intermediate in anhydrous ethanol, disperse it by ultrasonic vibration for 4 hours, and then add it dropwise to the ethyl orthosilicate dispersion for 3 hours. After the addition is completed, continue to heat up to 80°C, stir and react for 10 hours, remove excess solvent by rotary evaporation, add deionized water again, and add hydrochloric acid to adjust the pH to 3. After stirring and reacting for 1 hour, remove excess solvent by rotary evaporation, wash and dry the product twice with deionized water at a temperature of 0-4°C, and vacuum dry to constant weight to obtain a nano silicone resin polymer;

[0075] S2. Preparation of highly weather-resistant self-cleaning nano-silicon coating;

[0076] By weight, 50 parts of nano-silicone polyester resin were mixed with 40 parts of solvent, and 0.8 parts of antioxidant 1010, 0.3 parts of silicone defoaming agent, 0.8 parts of talc thixotropic agent, 2 parts of graphene, 4 parts of nano-additives and 0.3 parts of BYK333 leveling agent were added thereto. After high-speed stirring and mixing for 30 minutes, vacuum defoaming was performed to obtain a highly weather-resistant self-cleaning nano-silicone coating. Example

[0077] A preparation process of a highly weather-resistant self-cleaning nano-silicon coating comprises the following steps:

[0078] S1. Preparation of nano-silicon polyester resin;

[0079] By weight, 8 parts of pentaerythritol and 52 parts of ε-caprolactone were mixed, heated to 125-130° C., 0.1 parts of stannous octoate were added, stirred and reacted for 10 hours, cooled to room temperature, 25 parts of nano-silicone resin polymer were added thereto, and the mixture was mixed for 35 minutes, 14 parts of isophorone diisocyanate, 0.1 parts of p-hydroxyanisole and 10 parts of DMF were added, the mixture was heated to 70° C., the mixture was stirred and reacted for 3 hours, and the excess reaction solvent was removed by rotary evaporation to obtain a nano-silicone polyester resin;

[0080] Wherein, the preparation method of the nano silicone resin polymer is:

[0081] A. Disperse 1 part of 3-amino-4-fluorobenzoic acid in ether by weight, heat to 58°C, stir until mixed evenly, and cool to room temperature to obtain a 3-amino-4-fluorobenzoic acid dispersion;

[0082] Disperse 0.95 parts of ethyl trifluoroacetate in anhydrous ether, cool to constant temperature in an ice-water bath, stir for 25 minutes, slowly drop 3-amino-4-fluorobenzoic acid dispersion therein, control the temperature of the reaction system at 2-4°C during the dropwise addition, continue stirring the reaction for 6 hours after the dropwise addition, and remove excess solvent by rotary evaporation to obtain an amino-protected fluorobenzoic acid intermediate;

[0083] B. Disperse 1 part of amino-protected fluorobenzoic acid intermediate into pure DMF by weight, protect under nitrogen atmosphere, mix evenly at room temperature, add 0.08 part of benzenesulfonic acid, continue mixing for 25 minutes, and then slowly drop it into 0.4 part of tetramethoxysilane. During the dropwise addition, control the temperature of the reaction system to 72-78°C, and the dropwise addition time is 3 hours. After the dropwise addition is completed, continue stirring the reaction for 1 hour, and remove the excess solvent by rotary evaporation to obtain the methoxysilane intermediate;

[0084] C. Disperse 1.1 parts of tetraethyl orthosilicate in ethyl acetate by weight, heat to 78°C, mix evenly, add hydrochloric acid to adjust the pH to 4, continue to add deionized water, stir and react for 4 hours to obtain a tetraethyl orthosilicate dispersion;

[0085] Disperse 1 part of the methoxysilane intermediate in anhydrous ethanol, disperse it by ultrasonic vibration for 4 hours, and then add it dropwise to the ethyl orthosilicate dispersion for 3 hours. After the addition is completed, continue to heat up to 80°C, stir and react for 10 hours, remove excess solvent by rotary evaporation, add deionized water again, and add hydrochloric acid to adjust the pH to 3. After stirring and reacting for 1 hour, remove excess solvent by rotary evaporation, wash and dry the product twice with deionized water at a temperature of 0-4°C, and vacuum dry to constant weight to obtain a nano silicone resin polymer;

[0086] S2. Preparation of highly weather-resistant self-cleaning nano-silicon coating;

[0087] By weight, 62 parts of nano-silicone polyester resin were mixed with 30 parts of solvent, and 0.7 parts of antioxidant 1010, 0.3 parts of silicone defoaming agent, 1 part of talc thixotropic agent, 1.7 parts of graphene, 4 parts of nano-additives and 0.3 parts of BYK333 leveling agent were added thereto. After high-speed stirring and mixing for 30 minutes, vacuum defoaming was performed to obtain a highly weather-resistant self-cleaning nano-silicone coating.

[0088] Comparative Example 1. A process for preparing a highly weather-resistant self-cleaning nano-silicon coating, comprising the following steps:

[0089] Compared with Example 1, this comparative example did not prepare nano silicone polymer;

[0090] S1. Preparation of nano-silicon polyester resin;

[0091] By weight, 8 parts of pentaerythritol and 52 parts of ε-caprolactone were mixed, the temperature was raised to 125-130° C., 0.1 parts of stannous octoate were added, the mixture was stirred for reaction for 10 hours, the mixture was cooled to room temperature, 14 parts of isophorone diisocyanate, 0.1 parts of p-hydroxyanisole and 10 parts of DMF were added, the temperature was raised to 70° C., the mixture was stirred and reacted for 3 hours, and the excess reaction solvent was removed by rotary evaporation to obtain a nano-silicone polyester resin;

[0092] S2. Preparation of highly weather-resistant self-cleaning nano-silicon coating;

[0093] By weight, 50 parts of nano-silicone polyester resin were mixed with 40 parts of solvent, and 0.8 parts of antioxidant 1010, 0.3 parts of silicone defoaming agent, 0.8 parts of talc thixotropic agent, 2 parts of graphene, 4 parts of nano-additives and 0.3 parts of BYK333 leveling agent were added thereto. After high-speed stirring and mixing for 30 minutes, vacuum defoaming was performed to obtain a highly weather-resistant self-cleaning nano-silicone coating.

[0094] Testing: The coatings prepared in Examples 1-5 and Comparative Example 1 were applied to the surface of a concrete test block, placed in an environment of 25±2°C and a relative humidity of 70±5%, and dried and cured for 3 hours to obtain a test sample;

[0095] The test samples prepared in Examples 1-5 and Comparative Example 1 were tested for water drop contact angle and rolling angle using a contact angle meter;

[0096] According to DL / T693-1999, the test samples prepared in Examples 1-5 and Comparative Example 1 were tested for storage stability, coating appearance, water absorption, corrosion resistance, resistance to cold and hot cycles, and aging resistance.

[0097] When testing the corrosion resistance, the test conditions are to use a 30% sulfuric acid solution and immerse the sample in an environment of 20℃±5℃ for 30 days;

[0098] During the hot and cold cycle test, the test conditions are to place the sample in a 150±5℃ / 23±2℃ environment for 1h each, and cycle five times;

[0099] The test results are shown in the table below;

[0100]

[0101] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A preparation process of a highly weather-resistant self-cleaning nano-silicon coating, characterized in that: The following steps are involved: S1. Preparation of nano-silicon polyester resin; Pentaerythritol and ε-caprolactone are mixed, heated to 125-130°C, stannous octoate is added, stirred for reaction for 6-12 hours, cooled to room temperature, nano-silicone resin polymer is added thereto, mixed for 35-45 minutes, isophorone diisocyanate, inhibitor and reaction solvent are added, heated to 55-70°C, stirred for reaction for 2-4 hours, and excess reaction solvent is removed by rotary evaporation to obtain nano-silicone polyester resin; S2. Preparation of highly weather-resistant self-cleaning nano-silicon coating; The nano-silicon polyester resin is mixed with a solvent, and a weather-resistant antioxidant, a defoaming agent, a thixotropic agent, a wear-resistant additive, a nano-additive and a leveling agent are added thereto. After mixing at a high speed for 15-45 minutes, vacuum defoaming is performed to obtain a highly weather-resistant self-cleaning nano-silicon coating; In step S1, the preparation method of the nano silicone polymer is: A. Disperse 3-amino-4-fluorobenzoic acid in ether, heat to 45-70°C, stir until mixed evenly, and cool to room temperature to obtain a 3-amino-4-fluorobenzoic acid dispersion; disperse ethyl trifluoroacetate in anhydrous ether, cool to constant temperature in an ice-water bath, stir for 15-30 minutes, and then slowly dropwise add the 3-amino-4-fluorobenzoic acid dispersion thereto. During the dropwise addition, control the temperature of the reaction system to be 0-4°C. After the dropwise addition is completed, continue stirring the reaction for 2-8 hours, and then remove excess solvent by rotary evaporation to obtain an amino-protected fluorobenzoic acid intermediate; B. Disperse the amino-protected fluorobenzoic acid intermediate into pure DMF, protect under nitrogen atmosphere, mix evenly at room temperature, add benzenesulfonic acid, continue mixing for 15-30 minutes, and then slowly drop it into tetramethoxysilane. During the dropwise addition, control the temperature of the reaction system to 72-78°C, and the dropwise addition time is 1-4 hours. After the dropwise addition is completed, continue stirring the reaction for 0.5-1 hour, and remove excess solvent by rotary evaporation to obtain a methoxysilane intermediate; C. Disperse tetraethyl orthosilicate in ethyl acetate, heat to 75-80°C, mix evenly, add hydrochloric acid to adjust the pH to 3.8-4.2, continue to add deionized water, stir and react for 3-4 hours to obtain a tetraethyl orthosilicate dispersion; disperse the methoxysilane intermediate in anhydrous ethanol, ultrasonically disperse for 3-4 hours, add it dropwise to the tetraethyl orthosilicate dispersion for 2-4 hours, continue to heat to 78-80°C after the addition, stir and react for 8-12 hours, remove excess solvent by rotary evaporation, add deionized water again, and add hydrochloric acid to adjust the pH to 3-3.5, stir and react for 1 hour, remove excess solvent by rotary evaporation, wash the dried product with deionized water at a temperature of 0-4°C for 1-3 times, and vacuum dry to constant weight to obtain a nano silicone resin polymer.

2. The preparation process of a highly weather-resistant self-cleaning nano-silicon coating according to claim 1, characterized in that: In step S1, the nano-silicone polyester resin is composed of 8-10 parts of pentaerythritol, 52-70 parts of ε-caprolactone, 0.1-0.3 parts of stannous octoate, 10-25 parts of nano-silicone resin polymer, 14-18 parts of isophorone diisocyanate, 0.1-0.3 parts of inhibitor and 10-15 parts of reaction solvent in parts by weight.

3. The preparation process of a highly weather-resistant self-cleaning nano-silicon coating according to claim 1, characterized in that: In step S1, the polymerization inhibitor is p-hydroxyanisole; and the reaction solvent is DMF.

4. The preparation process of a highly weather-resistant self-cleaning nano-silicon coating according to claim 1, characterized in that: In step S2, the highly weather-resistant self-cleaning nano-silicon coating is composed of 50-60 parts of nano-silicon polyester resin, 30-40 parts of solvent, 0.5-1 part of weather-resistant antioxidant, 0.2-0.5 part of defoaming agent, 0.8-1.5 parts of thixotropic agent, 1-3 parts of wear-resistant additive, 4-5 parts of nano additive and 0.2-0.3 parts of leveling agent in parts by weight.

5. The preparation process of a highly weather-resistant self-cleaning nano-silicon coating according to claim 1, characterized in that: In step S2, the solvent is a mixed solvent of tetraethyl orthosilicate and octamethylcyclotetrasiloxane in a volume ratio of 7:3; the weather-resistant antioxidant is antioxidant 1010; the defoaming agent is a silicone defoaming agent; the thixotropic agent is talcum powder; the wear-resistant additive is graphene; the nano additive is nano silicon dioxide; and the leveling agent is BYK333 leveling agent.

6. The preparation process of a highly weather-resistant self-cleaning nano-silicon coating according to claim 1, characterized in that: In step A, the mass ratio of 3-amino-4-fluorobenzoic acid to ethyl trifluoroacetate is 1:(0.9-1) by weight.

7. The preparation process of a highly weather-resistant self-cleaning nano-silicon coating according to claim 1, characterized in that: In step B, the mass ratio of the amino-protected fluorobenzoic acid intermediate, benzenesulfonic acid and tetramethoxysilane is 1:(0.04-0.1):(0.4-1).

8. The preparation process of a highly weather-resistant self-cleaning nano-silicon coating according to claim 1, characterized in that: In step C, the mass ratio of the tetraethyl orthosilicate to the methoxysilane intermediate is (1.1-2.1):

1.

9. A highly weather-resistant self-cleaning nano-silicon coating prepared by the preparation method according to any one of claims 1 to 8.

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