Super-hydrophobic thermal insulation coating and preparation method thereof

Abstract

The invention relates to the technical field of thermal insulation materials and self-cleaning coating materials, and discloses a super-hydrophobic thermal insulation coating and a preparation method thereof. According to the invention, the modified hollow glass beads molded by double structures are embedded into the thermal insulation material taking fluorocarbon resin / acrylic resin / epoxy resin / polyurethane as a matrix; the surface aerogel effect and the middle hollow structure of the hollow glass beads molded by the double structures are the key points of the coating with excellent thermal insulation performance; the hollow glass beads molded by the double structures are subjected to hydrophobic modification and then mixed with resin and auxiliaries to form a super-hydrophobic coating with stable mechanical stability, and the super-hydrophobic coating can be stably attached to various substrates. According to the present invention, with the addition of the double-structure molded hollow glass bead in the thermal insulation coating material, the heat conductivity coefficient of the coating material is significantly reduced, the good thermal insulation effect is provided, and the unique ''upgraded raspberry'' microstructure and the low surface energy of the double-structure molded hollow glass bead provide excellent waterproof and self-cleaning performance.

Description

Technical Field

[0001] The present invention relates to the technical field of self-cleaning materials, and particularly to a superhydrophobic thermal insulation coating and a preparation method thereof. Background Art

[0002] As a surface-functionalized material, superhydrophobic coatings have attracted extensive research interest in the field of materials science in recent years. The principle of superhydrophobic coatings to achieve waterproofing and self-cleaning lies in their unique microstructure and surface chemical properties. The surface of superhydrophobic coatings has micron- or nano-scale concave and convex structures, and such a surface structure can greatly increase the contact angle with water molecules, thereby enabling the material surface to have a very strong repulsive ability to water. When a water droplet contacts such a surface, due to the large contact angle, the water droplet cannot spread out, so it exhibits high waterproofness, forming the so-called "lotus effect". This property makes superhydrophobic coatings show significant advantages in aspects such as waterproofing, anti-fouling, self-cleaning, and corrosion resistance.

[0003] There are various preparation methods for superhydrophobic coatings, including chemical vapor deposition method, spraying method, layer-by-layer self-assembly method, etc. These methods can form superhydrophobic surfaces on the surfaces of solid materials and have broad application prospects. The application fields of superhydrophobic coatings are very extensive, including the construction field, automotive industry, electronics industry, textile industry, military field, etc.

[0004] With the intensification of the global energy crisis and the improvement of environmental protection awareness, the demand for thermal insulation materials in fields such as construction and industry is increasing day by day. Therefore, designing and building energy-efficient building systems and improving the heat insulation and thermal insulation performance of buildings are crucial for reducing building energy consumption. The thermal insulation system of building walls is a key link to improve building energy efficiency, and thermal insulation coatings, as a new type of thermal insulation material, have been widely developed and applied in recent years. Existing thermal insulation materials generally mainly consist of solid materials, such as polystyrene boards, polyurethanes, etc. Although solid thermal insulation materials have a certain thermal insulation effect, they have problems such as serious pollution in the production process, difficult construction, high cost, and easy shedding. At the same time, thermal insulation materials occupy a large volume and cannot achieve comprehensive thermal insulation. Thermal insulation coatings overcome the limitations of traditional organic and inorganic thermal insulation materials in terms of the thickness of the thermal insulation layer and the aesthetics of buildings, have a significant thermal insulation effect, strong adhesion to the base layer, and at the same time have characteristics such as flame retardancy, environmental protection, high hardness, and wear resistance, and the construction process is relatively simple. Therefore, thermal insulation coatings have broad application prospects in many fields such as construction and industry.

[0005] According to different heat insulation mechanisms and methods, heat insulation coatings can be divided into three main types: barrier type, reflective type, and radiative type heat insulation coatings. Barrier type heat insulation coatings mainly achieve heat insulation and heat preservation effects through low thermal conductivity and high thermal resistance. Glass microspheres are a new type of multifunctional material that has emerged in recent years and are known for their light weight, low thermal conductivity, high strength, and excellent chemical stability. After special surface treatment, glass microspheres exhibit oleophilicity and hydrophobicity and are easily dispersed in organic material systems; Reflective heat insulation coatings utilize the principle of reflecting infrared heat and preventing heat conduction to insulate and keep warm, reducing heat transfer by convection and radiation, thereby reducing the heat absorption of the coating; Radiative heat insulation coatings utilize strong radiative properties after heat absorption to enhance heat exchange and effectively prevent heat from transferring into the wall, achieving heat insulation effects. Generally speaking, composite heat insulation coatings that integrate two or more heat insulation principles can effectively reflect most of the heat with their coatings, while releasing the absorbed heat in the form of radiation to the atmospheric window area and reducing the conduction of the remaining heat into the coating interior.

[0006] With the aggravation of urban air pollution and dust pollution, heat insulation coatings on building exteriors are facing increasingly severe challenges. Pollution and erosion, including the impact of wind and rain and the contamination of dust, can significantly reduce the performance of composite heat insulation coatings. These environmental factors not only affect the heat insulation effect of the coatings but may also lead to premature aging and damage of the coatings, thus failing to achieve the desired heat insulation and heat preservation effects.

[0007] In summary, there is still room for improvement in the currently used hydrophobic heat insulation coatings in practical applications. It is particularly important to develop a heat insulation coating with superhydrophobicity and self-cleaning functions. This new type of coating can repel moisture through its superhydrophobic properties, reduce the adhesion of dirt and dust, and its self-cleaning performance helps to keep the coating surface clean, thereby improving the service life and heat insulation effect of the coating. Therefore, it is of great significance to develop a heat insulation coating with superhydrophobicity and self-cleaning properties. Summary of the Invention

[0008] In order to achieve the above objectives, the present invention provides a superhydrophobic heat insulation coating and a preparation method thereof. Modified hollow glass microspheres with a dual structure are embedded in a heat insulation material based on fluorocarbon resin / acrylic resin / epoxy resin / polyurethane, and are coated on a substrate by spraying, brushing, etc., thereby obtaining a superhydrophobic heat insulation coating with an average static water contact angle of 160° and a rolling angle of 2°. While having good heat insulation performance, it also has excellent self-cleaning performance. The specific technical solutions are as follows:

[0009] A superhydrophobic heat insulation coating and a preparation method thereof, comprising the following steps:

[0010] A superhydrophobic thermal insulation coating, its preparation method and application, characterized by including the following steps:

[0011] S1: Prepare "raspberry-shaped" hollow glass microspheres:

[0012] S11: Pretreat the hollow glass microspheres: Add the hollow glass microspheres to a weakly alkaline solution, stir, filter, dry and screen them for later use;

[0013] S12: Prepare silica nanoparticles: Mix ethanol, ammonia water and deionized water, stir evenly and heat to about 50 °C, slowly drop tetraethoxysilane into the above mixed solution, and stir vigorously for 4-5 h to promote the reaction to obtain nano-silica sol;

[0014] S13: Prepare the "raspberry-shaped" structure: Add the hollow glass microspheres prepared in step S11 to the nano-silica sol prepared in step S12, drop silane coupling agents KH-550 and KH-792, immediately add solid oxalic acid, adjust the pH to 3, and then stir at 50 °C to obtain a "raspberry-shaped" hollow glass microsphere mixed sol;

[0015] Modification principle: The weakly alkaline solution corrodes the surface of the hollow glass microspheres, forming more active sites on its surface; tetraethoxysilane hydrolyzes in an alkaline environment to obtain silica sol, and the particle size of silica is about 100 nm (such as Figure 1 ), after adding hollow glass microspheres and silane coupling agents KH-550 and KH-792, chemical combination occurs (such as Figure 2 ), enhancing the stability of the structure.

[0016] S2: Prepare hollow glass microspheres with dual structure shaping:

[0017] S21: Prepare the dual structure: Add fumed silica to the "raspberry-shaped" hollow glass microsphere mixed sol prepared in step S13 and stir to obtain a hollow glass microsphere mixed sol with dual structure shaping;

[0018] Selection of fumed silica:

[0019] Fumed silica has a nanostructure, a high specific surface area, a low density, a low dielectric constant, and excellent heat insulation properties. Its surface is rich in siloxy groups and silanol groups. Silanol groups have high reactivity and can form hydrogen bonds or react with other groups, which not only ensures the construction of a stable network structure between silica particles but also enables good interaction between silica and other media. Therefore, fumed silica exhibits excellent reinforcement, toughening effects, as well as thickening, thixotropic, and anti-settling properties. In addition, the presence of silanol groups also provides the possibility for the surface modification of fumed silica. By selecting surface modifiers with different structures to react with silanol groups, various functional groups can be introduced onto the surface of fumed silica, making the functions of fumed silica more diverse and specialized.

[0020] S22: Particle modification: Drop cetyltrimethoxysilane / 1H,1H,2H,2H-perfluorodecyltrichlorosilane / methyltrimethoxysilane / trifluoropropylmethylcyclotrisiloxane as a hydrophobic modifier into the hollow glass microsphere hybrid sol with a dual structure prepared in step S21, stir and react at 60 °C for 3 h to obtain a modified hollow glass microsphere hybrid sol with a dual structure, and then concentrate it to a solid content of 50%;

[0021] The hollow glass microspheres can obtain a special "upgraded raspberry" structure after being treated with a dual structure. Its special "upgraded raspberry" structure provides a micro-nano composite papilla microstructure with a "lotus leaf effect". The hollow glass microspheres with a dual structure after hydrophobic modification treatment exhibit excellent hydrophobicity and self-cleaning properties while maintaining the heat insulation performance, and are easily dispersed in the organic material system. The hydrophobic modifier (low surface energy) molecules are composed of continuous carbon-hydrogen bonds or carbon-fluorine bonds. These non-polar bonds have weak intermolecular forces, resulting in relatively weak external forces of the whole molecule. Therefore, the surface energy is low. At the same time, the hydrophobic modifier molecules can form an ordered monolayer through self-assembly. This ordered arrangement further reduces the surface free energy because the ordered structure can reduce the molecular disorder, thereby reducing the surface energy and providing better superhydrophobic performance.

[0022] S3: Preparation of superhydrophobic thermal insulation coating:

[0023] S31: Paint preparation: Add titanium dioxide, wetting agent, thickening agent, pH regulator, and dispersant into water at room temperature, stir at low speed for 10 min to obtain a mixed solution; add fluorocarbon resin / acrylic resin / epoxy resin / polyurethane, film-forming agent, and leveling agent into the above mixed solution, and stir at high speed for 30 min to prepare a mixed emulsion;

[0024] S32: The hollow glass microsphere mixed sol formed by the modified double structure obtained in step 22 and the mixed coating obtained in step S31 are mixed uniformly in a certain proportion to obtain a super-hydrophobic thermal insulation coating;

[0025] S33: preparing a super-hydrophobic thermal insulation coating: uniformly mixing the super-hydrophobic thermal insulation coating prepared in S32 with a curing agent and then coating the mixture on a substrate to prepare a super-hydrophobic thermal insulation coating;

[0026] S34: Cross-linking and drying: After 4 hours of cross-linking reaction at room temperature, a super-hydrophobic thermal insulation coating can be obtained.

[0027] Principle: The unique "upgraded raspberry" structure of this invention boasts high structural stability and a self-sacrificing mechanism, resulting in a micro-nano roughness throughout the entire bulk. Even when damaged by external forces, it maintains the desired roughness. The addition of fumed silica also provides the entire system with an aerogel structure, resulting in a lower thermal conductivity, enhanced thermal insulation properties, and improved hydrophobicity and weather resistance of the entire coating. Furthermore, the hollow glass microspheres created by this dual structure are highly universal and can achieve a strong super-hydrophobic and thermally insulating effect with a variety of traditional resins.

[0028] Furthermore, in step S31, the components in the thermal insulation coating are calculated in weight percentage as follows: 60-75% emulsion, 9-15% titanium dioxide, 1.5-2.25% dispersant, 0.75-1.2% wetting agent, 1.5-2.25% film-forming agent, 0.9-1.2% thickener, 0.75-1.2% leveling agent, and the balance is water.

[0029] Furthermore, the dispersant is a polyacrylic acid dispersant SYF-601; the wetting agent is a nonionic wetting agent PE-100; the film-forming aid is alcohol ester-16 (200); the thickener is a polyether polyurethane thickener PT-67; the leveling agent is a polyether modified polydimethylsiloxane leveling agent BYK333, and the pH adjuster is an organic amine AMP-95.

[0030] The hollow glass microspheres have a particle size of 10-50 μm and a bulk density of 0.39 g / cm 3 , the true density is 0.6g / cm 3 The fumed silica is Evonik Degussa white carbon black R106, with a particle size of 7-14nm and a specific surface area of about 80-400m 2 / g; the titanium dioxide is nano-grade rutile.

[0031] Compared with the existing hydrophobic thermal insulation coating, the advantages of the present invention are:

[0032] The present invention embeds hollow glass microspheres with a modified dual structure into a thermal insulation material based on fluorocarbon resin / acrylic resin / epoxy resin / polyurethane, and coats it on a substrate by spraying, brushing and other methods; the aerogel effect on the surface of the hollow glass microspheres with a dual structure and the hollow structure in the middle are the keys to the excellent thermal insulation performance of the coating; the hollow glass microspheres with a dual structure are hydrophobically modified and then mixed with resins and additives to form a mechanically stable superhydrophobic coating, which can form stable adhesion with a variety of substrates. The hollow glass microspheres with a dual structure added in the thermal insulation coating not only significantly reduce the thermal conductivity of the coating and achieve a good thermal insulation effect, but also the unique "upgraded raspberry" microstructure and low surface energy of the hollow glass microspheres with a dual structure provide excellent waterproof and self-cleaning properties. The present invention can be constructed by various methods such as brushing, rolling, troweling or airless spraying, can be coated on various inorganic materials and self-cures at room temperature. At the same time, the hollow glass microspheres with a dual structure have strong universality and can achieve a strong superhydrophobic thermal insulation effect with a variety of traditional resins. Description of the Drawings

[0033] Hereinafter, the present invention will be described in more detail based on embodiments and with reference to the drawings. Among them:

[0034] Figure 1 is the schematic diagram of preparing silica sol by hydrolysis of TEOS;

[0035] Figure 2 is the schematic diagram of preparing "raspberry-shaped" hollow glass microspheres;

[0036] Figure 3 is the schematic diagram of preparing hollow glass microspheres with a dual structure;

[0037] Figure 4 is the static contact angle of Example 1;

[0038] Figure 5 is the static contact angle of Example 5. Detailed Description of the Invention

[0039] To further elaborate on the methods and effects achieved by the present invention, the technical solutions of the present invention will be clearly and completely described below in conjunction with examples and experimental examples.

[0040] Example 1

[0041] A superhydrophobic thermal insulation coating and its preparation method, characterized in that it includes the following steps:

[0042] 1. A superhydrophobic thermal insulation coating, its preparation method and application, characterized in that it includes the following steps:

[0043] S1: Prepare "raspberry-shaped" hollow glass microspheres:

[0044] S11: Pretreat the hollow glass microspheres: Add 10 parts of hollow glass microspheres into a weakly alkaline solution, stir, filter, dry and screen them for standby;

[0045] S12: Prepare silica nanoparticles: Mix 30 parts of ethanol, 6 parts of ammonia water and 12 parts of deionized water, stir evenly at a speed of 200 rpm and then heat to about 50 °C. Slowly drop 2 parts of tetraethoxysilane (99% TEOS) into the above mixed solution, and stir vigorously at a speed of 400 rpm for 4 - 5 h to promote the reaction to obtain nano-silica sol;

[0046] S13: Prepare the "raspberry-like" structure: Add the hollow glass microspheres prepared in step S11 into the nano-silica sol prepared in step S12, drop 1.4 parts of silane coupling agent KH-550 and 0.6 parts of KH-792, then immediately add 5 parts of oxalic acid solid, adjust the pH to 3, and then stir at 50 °C to obtain the "raspberry-like" hollow glass microsphere mixed sol;

[0047] S2: Prepare the hollow glass microspheres with dual structure shaping (such as Figure 3 )

[0048] S21: Prepare the dual structure: Add 30 parts of fumed silica into the "raspberry-like" hollow glass microsphere mixed sol prepared in step S13 and stir to obtain the hollow glass microsphere mixed sol with dual structure shaping;

[0049] S22: Particle modification: Drop 2 parts of cetyltrimethoxysilane as a hydrophobic modifier into the hollow glass microsphere mixed sol with dual structure shaping prepared in step S21, stir and react at 60 °C at a speed of 400 rpm for 3 h to obtain the modified hollow glass microsphere mixed sol with dual structure shaping, and then concentrate it to a solid content of 50%;

[0050] S3: Prepare the superhydrophobic thermal insulation coating:

[0051] S31: Paint mixing: Add 8 parts of titanium dioxide, 0.5 part of wetting agent PE-100, 0.3 part of thickener PT-67, 1 part of pH regulator AMP-95 and 1 part of dispersant SYF-601 into water at room temperature, stir at low speed for 10 min to obtain a mixed solution; Add 45 parts of fluorocarbon resin, 1 part of film-forming agent alcohol ester-16 (200) and 0.6 part of leveling agent BYK-333 into the above mixed solution, stir at high speed for 30 min to obtain a mixed emulsion;

[0052] S32: Mix the modified hollow glass microsphere mixed sol prepared in step 22 and the mixed coating prepared in step S31 evenly to obtain the superhydrophobic thermal insulation coating;

[0053] S33: preparing a super-hydrophobic thermal insulation coating: uniformly mixing the super-hydrophobic thermal insulation coating prepared in S32 with a curing agent at a ratio of fluorocarbon resin to curing agent of 1:1.5 (mass ratio), and spraying the mixture onto a substrate to prepare a super-hydrophobic thermal insulation coating;

[0054] S34: Cross-linking and drying: After 4 hours of cross-linking reaction at room temperature, a super-hydrophobic thermal insulation coating can be obtained.

[0055] Example 2

[0056] The second embodiment is identical to the first embodiment except for the following:

[0057] S1: Preparation of “raspberry-shaped” hollow glass microspheres:

[0058] S11: Pre-treating hollow glass microspheres: adding 10 parts of hollow glass microspheres into a weak alkaline solution, stirring, filtering, drying, and sieving for later use;

[0059] S12: Preparation of silica nanoparticles: 30 parts of ethanol, 6 parts of ammonia water and 12 parts of deionized water were mixed, stirred at 200 rpm, and heated to about 50°C. 2 parts of tetraethoxysilane (99% TEOS) were slowly added dropwise to the mixed solution, and vigorously stirred at 400 rpm for 4-5 hours to promote the reaction, thereby obtaining nano-silica silica sol;

[0060] S13: Preparing a "raspberry-shaped" structure: adding the hollow glass microspheres prepared in step S11 to the nano-silica silica sol prepared in step S12, and dropwise adding 1.4 parts of silane coupling agent KH-550 and 0.6 parts of KH-792, immediately adding 5 parts of oxalic acid solid, adjusting the pH to 3, and then stirring at 50° C. to obtain a "raspberry-shaped" hollow glass microsphere mixed sol;

[0061] S2: Preparation of hollow glass microspheres with double structure:

[0062] S21: Particle modification: 2 parts of hexadecyltrimethoxysilane as a hydrophobic modifier were added dropwise to the mixed sol of hollow glass microspheres with a double structure prepared in step S13, and the mixture was stirred at 400 rpm at 60° C. for 3 h to obtain a modified mixed sol of hollow glass microspheres with a double structure, and then concentrated to a solid content of 50%;

[0063] S3: Preparation of super hydrophobic thermal insulation coating:

[0064] S31: Paint mixing: At room temperature, add 8 parts of titanium dioxide, 0.5 part of wetting agent PE-100, 0.3 part of thickener PT-67, 1 part of pH regulator AMP-95, and 1 part of dispersant SYF-601 into water, and stir at low speed for 10 min to obtain a mixed solution; add 45 parts of fluorocarbon resin, 1 part of film-forming agent alcohol ester-16(200), and 0.6 part of leveling agent BYK-333 into the above mixed solution, and stir at high speed for 30 min to prepare a mixed emulsion;

[0065] S32: Mix the hollow glass microsphere mixed sol with modified dual structure prepared in step 21 and the mixed paint prepared in step S31 evenly to obtain a superhydrophobic thermal insulation paint;

[0066] S33: Prepare a superhydrophobic thermal insulation coating: Mix the superhydrophobic thermal insulation paint prepared in S32 and a curing agent evenly according to the mass ratio of fluorocarbon resin:curing agent = 1:1.5, and then spray it on a substrate to prepare a superhydrophobic thermal insulation coating;

[0067] S34: Crosslinking and drying: After a crosslinking reaction at room temperature for 4 h, a superhydrophobic thermal insulation coating can be obtained.

[0068] Example 3

[0069] Example 3 is the same as Example 1 except for the following content:

[0070] 1. A superhydrophobic thermal insulation paint and its preparation method and application, characterized by including the following steps:

[0071] S1: Prepare "raspberry-like" hollow glass microspheres:

[0072] S11: Pretreat the hollow glass microspheres: Add 10 parts of hollow glass microspheres into a weakly alkaline solution, stir, filter, dry, and screen them for later use;

[0073] S12: Prepare a dual structure: Mix 30 parts of ethanol, 6 parts of ammonia water, and 12 parts of deionized water, stir evenly at a speed of 200 rpm, and then heat to about 50 °C. Add the hollow glass microspheres prepared in step S11 and 30 parts of fumed silica into the above mixed solution and stir. After adding 1.4 parts of silane coupling agent KH-550 and 0.6 part of KH-792, immediately add 5 parts of oxalic acid solid, adjust the pH to 3, and then stir at 50 °C to prepare a hollow glass microsphere mixed sol with a dual structure;

[0074] S2: Prepare hollow glass microspheres with a dual structure:

[0075] S21: Particle modification: 2 parts of cetyltrimethoxysilane are added dropwise as a hydrophobic modifier to the hybrid sol of hollow glass microspheres with a dual structure prepared in step S12, and the mixture is stirred and reacted at 60 °C at a rotation speed of 400 rpm for 3 h to obtain a modified hybrid sol of hollow glass microspheres with a dual structure. Subsequently, it is concentrated to a solid content of 50%;

[0076] S3: Preparation of superhydrophobic thermal insulation coating:

[0077] S31: Paint preparation: At room temperature, 8 parts of titanium dioxide, 0.5 part of wetting agent PE-100, 0.3 part of thickener PT-67, 1 part of pH regulator AMP-95 and 1 part of dispersant SYF-601 are added to water, and the mixture is stirred at low speed for 10 min to obtain a mixed solution; 45 parts of fluorocarbon resin, 1 part of film-forming agent alcohol ester-16(200) and 0.6 part of leveling agent BYK-333 are added to the above mixed solution, and the mixture is stirred at high speed for 30 min to prepare a mixed emulsion;

[0078] S32: The modified hybrid sol of hollow glass microspheres with a dual structure prepared in step 21 is mixed evenly with the mixed coating prepared in step S31 to obtain a superhydrophobic thermal insulation coating;

[0079] S33: Preparation of superhydrophobic thermal insulation coating: The superhydrophobic thermal insulation coating prepared in S32 is mixed evenly with a curing agent at a mass ratio of fluorocarbon resin:curing agent = 1:1.5 and then sprayed on a substrate to obtain a superhydrophobic thermal insulation coating;

[0080] S34: Crosslinking and drying: After a crosslinking reaction at room temperature for 4 h, a superhydrophobic thermal insulation coating can be obtained.

[0081] Example 4

[0082] Example 4 is the same as Example 1 except for the following content:

[0083] S2: Preparation of hollow glass microspheres with a dual structure:

[0084] S21: Preparation of dual structure: 30 parts of fumed silica are added to the "raspberry-like" hollow glass microsphere hybrid sol prepared in step S13 and stirred to obtain a hollow glass microsphere hybrid sol with a dual structure;

[0085] S22: Particle modification: 2 parts of trifluoropropylmethylcyclotrisiloxane are added dropwise as a hydrophobic modifier to the hollow glass microsphere hybrid sol with a dual structure prepared in step S21, and the mixture is stirred and reacted at 60 °C at a rotation speed of 400 rpm for 3 h to obtain a modified hollow glass microsphere hybrid sol with a dual structure. Subsequently, it is concentrated to a solid content of 50%.

[0086] Example 5

[0087] Example 5 is the same as Example 1 except for the following content:

[0088] S2: Prepare hollow glass microspheres with a dual structure:

[0089] S21: Prepare the dual structure: Add 30 parts of fumed silica to the "raspberry-type" hollow glass microsphere hybrid sol prepared in step S13 and stir to obtain a hollow glass microsphere hybrid sol with a dual structure;

[0090] S22: Particle modification: Drop 2 parts of 1H,1H,2H,2H-perfluorodecyltrichlorosilane as a hydrophobic modifier into the hollow glass microsphere hybrid sol with a dual structure prepared in step S21, stir and react at 60 °C at a speed of 400 rpm for 3 h to obtain a modified hollow glass microsphere hybrid sol with a dual structure, and then concentrate it to a solid content of 50%.

[0091] Example 6

[0092] Example 6 is the same as Example 1 except for the following content:

[0093] S2: Prepare hollow glass microspheres with a dual structure:

[0094] S21: Prepare the dual structure: Add 30 parts of fumed silica to the "raspberry-type" hollow glass microsphere hybrid sol prepared in step S13 and stir to obtain a hollow glass microsphere hybrid sol with a dual structure;

[0095] S22: Particle modification: Drop 2 parts of methyltrimethoxysilane as a hydrophobic modifier into the hollow glass microsphere hybrid sol with a dual structure prepared in step S21, stir and react at 60 °C at a speed of 400 rpm for 3 h to obtain a modified hollow glass microsphere hybrid sol with a dual structure, and then concentrate it to a solid content of 50%.

[0096] Example 7

[0097] Example 7 is the same as Example 1 except for the following content:

[0098] S3: Prepare a superhydrophobic thermal insulation coating:

[0099] S31: Paint preparation: Add 8 parts of titanium dioxide, 0.5 part of wetting agent PE-100, 0.3 part of thickener PT-67, 1 part of pH regulator AMP-95 and 1 part of dispersant SYF-601 to water at room temperature, stir at low speed for 10 min to obtain a mixed solution; add 45 parts of epoxy resin, 1 part of film-forming agent alcohol ester-16(200) and 0.6 part of leveling agent BYK-−333 to the above mixed solution, stir at high speed for 30 min to obtain a mixed emulsion;

[0100] S32: Mix the hollow glass microsphere hybrid sol with a modified dual structure prepared in Step 21 and the hybrid coating prepared in Step S31 evenly to obtain a superhydrophobic thermal insulation coating;

[0101] S33: Prepare a superhydrophobic thermal insulation coating: Mix the superhydrophobic thermal insulation coating prepared in S32 and a curing agent evenly at an epoxy resin:curing agent mass ratio of 1:1.5, and then spray the mixture onto a substrate to obtain a superhydrophobic thermal insulation coating;

[0102] S34: Crosslink and dry: After a 4-hour crosslinking reaction at room temperature, a superhydrophobic thermal insulation coating can be obtained.

[0103] Example Eight

[0104] Example Eight is the same as Example One except for the following content:

[0105] S3: Prepare a superhydrophobic thermal insulation coating:

[0106] S31: Paint mixing: At room temperature, add 8 parts of titanium dioxide, 0.5 part of wetting agent PE-100, 0.3 part of thickener PT-67, 1 part of pH regulator AMP-95, and 1 part of dispersant SYF-601 to water, and stir at low speed for 10 minutes to obtain a mixture; add polyurethane, 1 part of film-forming agent alcohol ester-16(200), and 0.6 part of leveling agent BYK-333 to the above mixture, and stir at high speed for 30 minutes to obtain a hybrid emulsion;

[0107] S32: Mix the hollow glass microsphere hybrid sol with a modified dual structure prepared in Step 21 and the hybrid coating prepared in Step S31 evenly to obtain a superhydrophobic thermal insulation coating;

[0108] S33: Prepare a superhydrophobic thermal insulation coating: Mix the superhydrophobic thermal insulation coating prepared in S32 and a curing agent evenly at a polyurethane:curing agent mass ratio of 1:1.5, and then spray the mixture onto a substrate to obtain a superhydrophobic thermal insulation coating;

[0109] S34: Crosslink and dry: After a 4-hour crosslinking reaction at room temperature, a superhydrophobic thermal insulation coating can be obtained.

[0110] Example Nine

[0111] Example Nine is the same as Example One except for the following content:

[0112] S3: Prepare a superhydrophobic thermal insulation coating:

[0113] S31: Paint mixing: At room temperature, add 8 parts of titanium dioxide, 0.5 part of wetting agent PE-100, 0.3 part of thickener PT-67, 1 part of pH regulator AMP-95, and 1 part of dispersant SYF-601 to water, and stir at low speed for 10 min to obtain a mixed solution; add 45 parts of acrylic resin, 1 part of film-forming agent alcohol ester-16 (200), and 0.6 part of leveling agent BYK-333 to the above mixed solution, and stir at high speed for 30 min to prepare a mixed emulsion;

[0114] S32: Mix the hollow glass microsphere mixed sol prepared by the modified double structure shaping in step 21 and the mixed coating prepared in step S31 evenly to obtain a superhydrophobic thermal insulation coating;

[0115] S33: Prepare a superhydrophobic thermal insulation coating: Mix the superhydrophobic thermal insulation coating prepared in S32 and a curing agent evenly according to the mass ratio of acrylic resin:curing agent = 1:1.5, and spray it on a substrate to prepare a superhydrophobic thermal insulation coating;

[0116] S34: Crosslinking and drying: After a crosslinking reaction at room temperature for 4 h, a superhydrophobic thermal insulation coating can be obtained.

[0117] Experimental Example 1

[0118] Experimental Example 1 is to compare the effects of different double-structure-shaped hollow glass microsphere mixed sols prepared in Comparative Example 1, Example 2, and Example 3 on the heat insulation effect of the finally prepared superhydrophobic thermal insulation coating. The results are shown in Table 1:

[0119] Table 1 Effects of different double-structure-shaped hollow glass microsphere mixed sols in Examples 1-3 on the heat preservation effect of the final product

[0120] <![CDATA[Adhesion (scratch method) a > Thermal conductivity <![CDATA[Thermal insulation effect of 10mm coating b > Example 1 ≤ Level 1 0.048 60℃ Example 2 ≤ Level 1 0.058 51℃ Example 2 ≤ Level 1 0.054 55℃

[0121] a: Coated on the surface of a 45# steel substrate, and tested according to GB / T 1720 after thorough drying

[0122] b: The substrate temperature is 400 °C, and the surface temperature of the coating is tested after heat preservation for 1 h

[0123] The data in Table 1 show that the superhydrophobic thermal insulation coating prepared with the hollow glass microsphere mixed sol shaped by a double structure with an "upgraded raspberry" structure has the smallest thermal conductivity and the best heat preservation effect. Therefore, the hollow glass microsphere mixed sol shaped by a double structure with an "upgraded raspberry" structure is selected as the component of the present invention.

[0124] Experimental Example 2

[0125] Experimental Example 2 aims to compare the effects of different hydrophobic modifiers in the present invention on the hydrophobicity of the final product. Specifically, after the superhydrophobic thermal insulation coating is dried, the contact angle of water droplets on its surface is used as the evaluation criterion, as shown in Table 2. The blank control group is the existing common technology of mixing hollow glass beads and emulsion.

[0126] Table 2 Effects of different hydrophobic modifiers on the hydrophobic performance of the final product

[0127] Example 1 Example 4 Example 5 Example 6 Blank control group Contact angle 156° 157° 160° 151° 100°

[0128] Table 2 shows that by adding hollow glass microspheres with a dual structure shaped by the "upgraded raspberry" structure and different hydrophobic modifiers, the contact angle of the thermal insulation coating has increased, and the hydrophobic performance of the thermal insulation coating has been improved, reaching up to 160° at most; compared with the blank control group, the hollow glass microspheres shaped by the dual structure can further improve the hydrophobic performance of the thermal insulation coating, indicating that a rough micro-nano composite structure similar to the "lotus effect" has been constructed on the surface of the thermal insulation coating after spraying, increasing the static contact angle (such as Figure 4 、 Figure 5 ).

[0129] Experimental Example 3

[0130] Experimental Example 3 aims to verify the universality of the hollow glass microspheres with a dual structure shaped by the "upgraded raspberry" structure in the present invention for resins. Specifically, after the superhydrophobic coating is dried, the contact angle of water droplets on its surface is used as the evaluation criterion, as shown in Table 3

[0131] Table 3 Effects of different resins on the hydrophobic performance of the final product

[0132] Example 1 Example 7 Example 8 Example 9 Contact angle 156° 154° 157° 156°

[0133] Table 3 shows that the hollow glass microspheres with a dual structure shaped by the "upgraded raspberry" structure of the present invention are effective for different resins and have universality. Its unique "upgraded raspberry" micro-structure and low surface energy provide excellent waterproof and self-cleaning properties.

[0134] Although the present invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed, as long as they do not depart from the spirit and scope of the present invention as defined by the appended claims. It should be understood that the different dependent claims and the features described herein can be combined in a manner different from that described in the original claims. It should also be understood that the features described in connection with a single embodiment can be used in other described embodiments.

Claims

1. A preparation method of a superhydrophobic thermal insulation coating, characterized in that, It includes the following steps: S1: Add hollow glass microspheres into nano-silica sol, drop silane coupling agents KH-550 and KH-792, and then immediately add solid oxalic acid to adjust the pH, obtaining a "raspberry-shaped" hollow glass microsphere mixed sol: S2: Add fumed silica into the "raspberry-shaped" hollow glass microsphere mixed sol to prepare a hollow glass microsphere mixed sol with dual structure shaping; perform particle modification on the hollow glass microsphere mixed sol with dual structure shaping; S3: Mix the modified hollow glass microsphere mixed sol with dual structure shaping prepared in step 2 with a thermal insulation coating to obtain a superhydrophobic thermal insulation coating; uniformly mix the superhydrophobic thermal insulation coating with a curing agent and then coat it on a substrate to prepare a superhydrophobic thermal insulation coating.

2. The preparation method of the superhydrophobic thermal insulation coating according to claim 1, wherein Step S1 includes: S11: Pretreat the hollow glass microspheres: Add the hollow glass microspheres into a weakly alkaline solution, stir, filter, dry, and screen them for standby; S12: Prepare silica nanoparticles: Mix ethanol, ammonia water, and deionized water, stir evenly, heat to about 50 °C, and slowly drop tetraethoxysilane into the above mixed solution, stir vigorously for 4 - 5 h to promote the reaction, obtaining nano-silica sol; S13: Prepare the "raspberry-shaped" structure: Add the hollow glass microspheres prepared in step S11 into the nano-silica sol prepared in step S12, drop silane coupling agents KH-550 and KH-792, and then immediately add solid oxalic acid to adjust the pH to 3, and then stir at 50 °C to obtain a "raspberry-shaped" hollow glass microsphere mixed sol.

3. The preparation method of the superhydrophobic thermal insulation coating according to claim 1, wherein Step S2 includes: S21: Prepare the dual structure: Add fumed silica into the "raspberry-shaped" hollow glass microsphere mixed sol prepared in step S13 and stir to prepare a hollow glass microsphere mixed sol with dual structure shaping; S22: Particle modification: Drop cetyltrimethoxysilane / 1H,1H,2H,2H-perfluorodecyltrichlorosilane / methyltrimethoxysilane / trifluoropropylmethylcyclotrisiloxane as a hydrophobic modifier into the hollow glass microsphere mixed sol with dual structure shaping prepared in step S21, stir and react at 60 °C for 3 h to obtain a modified hollow glass microsphere mixed sol with dual structure shaping, and then concentrate it to a solid content of 50%.

4. The preparation method of the superhydrophobic thermal insulation coating according to claim 1, wherein, Step S3 includes: S31: Add titanium dioxide, wetting agent, thickening agent, pH regulator, and dispersant into water at room temperature, stir at low speed for 10 min to obtain a mixed solution; add fluorocarbon resin / acrylic resin / epoxy resin / polyurethane, film-forming agent, and leveling agent into the above mixed solution, stir at high speed for 30 min to prepare a mixed emulsion; S32: Mix the modified hollow glass microsphere mixed sol with dual structure shaping prepared in step 22 with the mixed coating prepared in step S31 in a certain proportion and mix evenly to obtain a superhydrophobic thermal insulation coating; S33: Prepare a superhydrophobic thermal insulation coating: Uniformly mix the superhydrophobic thermal insulation coating prepared in S32 with a curing agent and then coat it on a substrate to prepare a superhydrophobic thermal insulation coating; S34: After a crosslinking reaction at room temperature for 4 h, obtain a superhydrophobic thermal insulation coating.

5. The superhydrophobic thermal insulation coating prepared by the preparation method according to claim 1, characterized in that The components in the superhydrophobic thermal insulation coating are as follows by weight percentage: 60-75% emulsion, 9-15% titanium dioxide, 1.5-2.25% dispersant, 0.75-1.2% wetting agent, 1.5-2.25% film-forming agent, 0.9-1.2% thickener, 0.75-1.2% leveling agent, and the balance is water.

6. The superhydrophobic thermal insulation coating prepared by the preparation method according to claim 4, characterized in that, The dispersant is polyacrylic acid dispersant SYF-601; the wetting agent is non-ionic wetting agent PE-100; the film-forming aid is alcohol ester-16; the thickener is polyether polyurethane thickener PT-67; the leveling agent is polyether-modified polydimethylsiloxane leveling agent BYK333; the pH regulator is organic amine AMP-95.

7. The superhydrophobic thermal insulation coating prepared by the preparation method according to claim 4, characterized in that, The hollow glass microspheres have a particle size of 10 - 50 μm and a bulk density of 0.39 g / cm 3 , and a true density of 0.6 g / cm 3 ; the fumed silica is Evonik Degussa silica R106 with a particle size of 7 - 14 nm and a specific surface area of 80 - 400 m 2 / g; the titanium dioxide is nanoscale rutile type.

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