Anti-fogging coating containing aerogel and process for its preparation

Abstract

This invention relates to an anti-condensation coating containing aerogel and its preparation process, belonging to the field of architectural coatings technology. It comprises the following components by weight: 25-50 parts aerogel, 10-25 parts compound filler, 30-50 parts polymer emulsion, 10-15 parts infrared reflective filler, 5-15 parts film-forming aid, 0.5-1 part dispersant, 0.5-2 parts defoamer, 1-3 parts leveling agent, and 15-30 parts deionized water. The coating prepared by this invention has a low thermal conductivity and excellent anti-condensation properties; an application thickness of 3 mm is sufficient to produce an effect.

Description

Technical Field

[0001] This invention belongs to the field of architectural coatings technology, and relates to an anti-condensation coating containing aerogel and its preparation process. Background Technology

[0002] Condensation is a natural process in which water vapor condenses into liquid water when it comes into contact with a surface of an object whose temperature is lower than its dew point. In the construction industry, condensation is commonly found on the interior surfaces of exterior walls, basements, warehouses, pipes, and interior walls during the "return to spring" and plum rain seasons in southern my country. This condensation phenomenon not only affects aesthetics but also the safety and lifespan of buildings and equipment.

[0003] Currently, the main methods to prevent condensation include equipment or building structural design, adding insulation layers, and using anti-condensation coatings. Among these, structural design is costly and complex to construct; adding insulation layers is complex, costly, and takes up indoor space; while anti-condensation coatings are widely used due to their advantages such as simple construction, low cost, and no impact on the building structure.

[0004] Existing anti-condensation coatings suffer from several drawbacks. Firstly, coatings with breathability and water absorption are prone to water saturation, resulting in short-lived anti-condensation effects and reduced adhesion due to coating swelling from water absorption. Secondly, anti-condensation coatings based on thermal insulation materials require thick layers (7mm or more) to achieve the desired effect, leading to higher costs. Aerogels, as novel nanoporous materials, possess extremely high specific surface area, extremely low thermal conductivity, and excellent porosity, demonstrating significant potential in the field of thermal insulation. Theoretically, their application in coatings could achieve extremely high thermal insulation efficiency with very low addition amounts, thus avoiding performance degradation caused by excessive fillers. However, the inherent high hydrophilicity, low strength, and difficulty in dispersing and stabilizing in liquid systems of aerogel materials present significant challenges to their direct introduction into coating systems.

[0005] Therefore, developing anti-condensation coatings containing aerogel that have strong adhesion, can be applied in thin layers, and have a long-lasting effect is an urgent problem to be solved. Summary of the Invention

[0006] The purpose of this invention is to provide an anti-condensation coating containing aerogel and its preparation process. The coating prepared by this invention has a low thermal conductivity (≤0.030W / (m·K)) and excellent anti-condensation properties.

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] On one hand, the present invention provides an anti-condensation coating containing aerogel, comprising the following parts by weight: 25-50 parts aerogel, 10-25 parts compound filler, 30-50 parts polymer emulsion, 10-15 parts infrared reflective filler, 5-15 parts film-forming aid, 0.5-1 part dispersant, 0.5-2 parts defoamer, 1-3 parts leveling agent, and 15-30 parts deionized water;

[0009] The composite filler is vitrified microspheres and mica powder in a mass ratio of 1:1; the infrared reflective filler is antimony-doped rutile TiO2 that has undergone poly(N-isopropylacrylamide) surface treatment.

[0010] Furthermore, the aerogel undergoes pretreatment before use, the specific process of which is as follows:

[0011] The aerogel is dispersed in an aqueous acrylic emulsion with a mass concentration of 25-35%, wherein the mass ratio of the aqueous acrylic solution to the aerogel is (1-2):1. The mixture is stirred at 300 r / min for 35-50 min and then dried to obtain the aerogel for later use.

[0012] Furthermore, the aerogel particles have an average particle size of 100 μm and are one or more of silica aerogel particles, titanium dioxide aerogel particles, zirconium dioxide aerogel particles, and aluminum oxide aerogel particles.

[0013] Furthermore, the polymer emulsion is a silicone-modified acrylic emulsion and silica sol in a mass ratio of 10:1.

[0014] Furthermore, the preparation process of the infrared reflective filler is as follows:

[0015] A titanium tetrachloride solution with a mass fraction of 45% was prepared, and antimony trichloride was added and mixed evenly. The molar ratio of Ti to Sb was 90:5. The titanium tetrachloride solution with a volume ratio of 1:1 was pyrolyzed with the aqueous solution at 100°C for 2 hours, and then aged for 6 hours. After filtration and drying, it was first calcined at 300°C for 2 hours, and then heated to 500°C for 2 hours. After cooling and pulverizing, antimony-doped rutile TiO2 nanoparticles were obtained.

[0016] Subsequently, antimony-doped rutile TiO2 nanoparticles were dispersed in a 40wt% ethanol aqueous solution to form a stable suspension. Then, poly(N-isopropylacrylamide) was added to the suspension to form a mixture. The mixture was stirred at room temperature for 2-3 hours, filtered, washed, and dried to obtain the infrared reflective filler. The mass ratio of antimony-doped rutile TiO2 nanoparticles to poly(N-isopropylacrylamide) was 1:(0.5-0.6).

[0017] Furthermore, the defoamer is one or more of mineral oils, organosilicones, and polyethers.

[0018] Furthermore, the film-forming aid is one or more of the following: dodecyl alcohol ester, propylene glycol butyl ether, propylene glycol phenyl ether, ethylene glycol butyl ether acetate, and propylene glycol methyl ether acetate.

[0019] Furthermore, the dispersant is one or more of the following: polycarboxylate dispersants, polyacrylic acid, sodium polyacrylate, polyvinyl alcohol, and polyethylene glycol.

[0020] Furthermore, the leveling agent is a silicone-based leveling agent or an acrylate-based leveling agent.

[0021] On the other hand, the present invention provides a preparation process for an anti-condensation coating containing aerogel as described above, comprising the following steps:

[0022] S1. According to the mass fraction, mix deionized water, dispersant and 50% defoamer, stir at 300~500 rpm for 35~50 min, add the prepared aerogel, stir thoroughly to make the aerogel completely liquid wetted to obtain mixture A.

[0023] S2. Mix the polymer emulsion and the compound filler, disperse at a speed of 2000~3000 rpm for 25~45 min, then add the film-forming aid and leveling agent, and continue to disperse at the same speed for 25~40 min to obtain mixture B;

[0024] S3. Add mixture A to mixture B and disperse at 800-1000 rpm for 20-40 minutes. Then add the remaining 50% of defoamer and infrared reflective filler and stir for 25-35 minutes to obtain the anti-condensation coating containing aerogel.

[0025] The beneficial effects of this invention are:

[0026] This invention provides an anti-condensation coating containing aerogel. It uses an organosilicon-modified acrylic emulsion as the main polymer base and employs a triple-barrier system composed of aerogel and compound fillers. The aerogel is the core functional component, lightweight porous vitrified microspheres serve as auxiliary insulation, and flake-shaped mica powder acts as a water vapor barrier and reinforcement. These components synergistically enhance the anti-condensation effect of the coating with the thermal insulation properties of the aerogel. Simultaneously, by adding infrared-reflective fillers treated with poly(N-isopropylacrylamide) surface treatment, near-infrared radiation is reflected, reducing the heat input from external heat sources to the coating. Combined with the aerogel, this achieves synergistic control of both conductive and radiative heat transfer, improving the coating's thermal insulation effect. In the coating preparation process, the aerogel is first wetted and then dispersed, avoiding the formation of undispersible hard agglomerates and structural damage during mixing. Therefore, the prepared coating exhibits excellent thermal insulation and anti-condensation properties. Detailed Implementation

[0027] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with embodiments, is provided below.

[0028] In order to develop a coating that can inherit the excellent thermal insulation properties of aerogel and also form a coating with efficient anti-condensation function, the present invention provides an anti-condensation coating containing aerogel, comprising the following parts by weight: 25-50 parts aerogel, 10-25 parts compound filler, 30-50 parts polymer emulsion, 10-15 parts infrared reflective filler, 5-15 parts film-forming aid, 0.5-1 part dispersant, 0.5-2 parts defoamer, 1-3 parts leveling agent and 15-30 parts deionized water;

[0029] The composite filler is vitrified microspheres and mica powder in a mass ratio of 1:1; the infrared reflective filler is antimony-doped rutile TiO2 that has undergone poly(N-isopropylacrylamide) surface treatment.

[0030] This invention selects a silicone-modified acrylic emulsion as the main polymer base. It combines the hydrophobicity and weather resistance of silicone with the elasticity and adhesion of acrylic, thus resisting substrate stress cracking caused by temperature changes and preventing condensation penetration due to cracks. An inorganic / organic composite system of silicone-modified acrylic emulsion and silica sol is used. After the inorganic coating film is formed, it creates a microporous structure with excellent moisture permeability, complementing the thermal insulation of aerogel and the elasticity of organic emulsion, thereby improving the coating's performance. Therefore, a balance between moisture barrier and permeability can be achieved in the coating. Appropriate permeability allows trace amounts of moisture inside the wall to escape, preventing condensation at the coating-substrate interface, which could lead to loss of adhesion and internal mold growth.

[0031] This invention uses aerogel and composite fillers to form a triple barrier system. Aerogel is the core functional component, lightweight porous filler vitrified microspheres are the auxiliary heat insulation component, and sheet-like filler mica powder is the water vapor barrier and reinforcement component. The combined effect of aerogel and composite filler is far superior to using aerogel or a single filler alone.

[0032] The coating prepared by this invention has a three-dimensional network structure skeleton. Its low thermal conductivity can reduce the heat transfer from the surface coating to the interior of the wall. At the same time, by adding infrared reflective fillers, the coating has high light and heat reflectivity. Therefore, it can compensate for the performance reduction caused by insufficient thickness of the surface coating and ensure the effect of the entire coating.

[0033] In one specific embodiment, the aerogel undergoes pretreatment before use, the specific process of which is as follows:

[0034] The aerogel is dispersed in an aqueous acrylic emulsion with a mass concentration of 25-35%, wherein the mass ratio of the aqueous acrylic solution to the aerogel is (1-2):1. The mixture is stirred at 300 r / min for 35-50 min and then dried to obtain the aerogel for later use.

[0035] In one specific embodiment, the aerogel particles have an average particle size of 100 μm and are one or more of silica aerogel particles, titanium dioxide aerogel particles, zirconium dioxide aerogel particles, and aluminum oxide aerogel particles.

[0036] The original aerogel nanoframework is fragile, with low strength and high brittleness. Surface treatment with water-based acrylic emulsion improves its interfacial compatibility with the polymer emulsion, enhancing dispersion stability and film density. After drying, the water-based acrylic emulsion forms a flexible polymer film on the surface of the aerogel particles and at the pore inlets, improving the aerogel's compressive and shear strength, enabling it to withstand mechanical forces during subsequent coating production and use, and protecting its nanoporous structure from damage. Simultaneously, the surface coating effectively prevents water molecules from directly contacting the aerogel core, improving its performance stability and facilitating better synergistic effects with compound fillers.

[0037] In one specific embodiment, the polymer emulsion is a silicone-modified acrylic emulsion and silica sol in a mass ratio of 10:1.

[0038] At this ratio, by adjusting the organic resin and inorganic materials, the optimal balance between the coating's thermal conductivity and water vapor permeability can be achieved.

[0039] In one specific embodiment, the preparation process of the infrared reflective filler is as follows:

[0040] A titanium tetrachloride solution with a mass fraction of 45% was prepared, and antimony trichloride was added and mixed evenly. The molar ratio of Ti to Sb was 90:5. The titanium tetrachloride solution with a volume ratio of 1:1 was pyrolyzed with the aqueous solution at 100°C for 2 hours, and then aged for 6 hours. After filtration and drying, it was first calcined at 300°C for 2 hours, and then heated to 500°C for 2 hours. After cooling and pulverizing, antimony-doped rutile TiO2 nanoparticles were obtained.

[0041] Subsequently, antimony-doped rutile TiO2 nanoparticles were dispersed in a 40wt% ethanol aqueous solution to form a stable suspension. Then, poly(N-isopropylacrylamide) was added to the suspension to form a mixture. The mixture was stirred at room temperature for 2-3 hours, filtered, washed, and dried to obtain the infrared reflective filler. The mass ratio of antimony-doped rutile TiO2 nanoparticles to poly(N-isopropylacrylamide) was 1:(0.5-0.6).

[0042] Rutile titanium dioxide belongs to the tetragonal crystal system, characterized by high atomic packing density and a small unit lattice. This unique lattice structure endows it with an extremely high refractive index, far exceeding that of common white pigments. This high refractive index causes strong scattering of light, including infrared light, at the particle surface, resulting in extremely high reflectivity for near-infrared radiation, a major source of heat in solar radiation. Antimony doping can introduce impurity energy levels (such as Sb) into the band gap of rutile titanium dioxide. 5 ⁺ / Sb 3 By narrowing the bandgap (the energy level of ⁺), the material can absorb lower-energy infrared light, thereby enhancing its absorption of infrared light and increasing its infrared reflectivity.

[0043] Furthermore, to improve the dispersibility of infrared reflective fillers and prevent agglomeration, surface treatment with poly(N-isopropylacrylamide) can improve the dispersibility of antimony-doped rutile TiO2 nanoparticles in the medium, reduce agglomeration, and help form a more effective light-reflecting network, further enhancing the coating's performance. Simultaneously, poly(N-isopropylacrylamide) is thermosensitive and hydrophobic at high temperatures, facilitating the rapid sliding off of formed micro-condensation droplets, thus keeping the surface dry and improving the coating's anti-condensation properties.

[0044] In this invention, the aerogel primarily maintains heat by inhibiting heat conduction, preventing the surface temperature from becoming too low. Therefore, infrared reflective filler is added to it to reflect near-infrared radiation, thereby reducing the heat input to the coating from external heat sources (such as sunlight or indoor heat sources) at the source. The combination of these two methods achieves synergistic control of both conduction and radiation heat transfer, improving the coating's heat preservation effect.

[0045] In one specific embodiment, the defoamer is one or more of mineral oils, organosilicones, and polyethers.

[0046] In one specific embodiment, the film-forming aid is one or more of dodecyl alcohol ester, propylene glycol butyl ether, propylene glycol phenyl ether, ethylene glycol butyl ether acetate, and propylene glycol methyl ether acetate.

[0047] In one specific embodiment, the dispersant is one or more of polycarboxylate dispersants, polyacrylic acid, sodium polyacrylate, polyvinyl alcohol, and polyethylene glycol.

[0048] In one specific embodiment, the leveling agent is a silicone-based leveling agent or an acrylate-based leveling agent.

[0049] This invention incorporates film-forming aids to help emulsion polymer particles fuse together after application to form a continuous, dense, and smooth paint film. The addition of defoamers inhibits foam generation during coating preparation and application, and eliminates any existing foam. The invention selects polymeric dispersants to prevent the aggregation of components in the coating, ensuring that aerogel and filler particles are stably suspended in the coating system, preventing sedimentation and agglomeration, and thus enhancing coating performance. The leveling agent improves the rheological properties of the coating, allowing it to flow and spread better after application, forming a smooth and even surface.

[0050] On the other hand, the present invention provides a preparation process for an anti-condensation coating containing aerogel as described above, comprising the following steps:

[0051] S1. According to the mass fraction, mix deionized water, dispersant and 50% defoamer, stir at 300~500 rpm for 35~50 min, add the prepared aerogel, stir thoroughly to make the aerogel completely liquid wetted to obtain mixture A.

[0052] S2. Mix the polymer emulsion and the compound filler, disperse at a speed of 2000~3000 rpm for 25~45 min, then add the film-forming aid and leveling agent, and continue to disperse at the same speed for 25~40 min to obtain mixture B;

[0053] S3. Add mixture A to mixture B and disperse at 800-1000 rpm for 20-40 minutes. Then add the remaining 50% of defoamer and infrared reflective filler and stir for 25-35 minutes to obtain the anti-condensation coating containing aerogel.

[0054] In the coating preparation process of this invention, the aerogel is first wetted and then dispersed, which avoids directly adding the aerogel to a high-viscosity system and thus preventing the formation of undispersible hard agglomerates. Specifically, prolonged low-speed stirring ensures that the dispersant and defoamer are completely dissolved and uniformly distributed in water, reaching their optimal active state and preparing for subsequent efficient powder dispersion. Adding half of the defoamer in advance effectively suppresses the large number of bubbles generated by air entrainment in the powder during subsequent powder addition, creating a low-foaming environment that facilitates powder wetting. Simultaneously, low-speed stirring prevents the fragile porous nanostructure of the aerogel from being damaged under high-speed shear, protecting its core thermal insulation properties. Mixing the polymer emulsion and compound filler ensures uniform emulsion mixing and avoids the degradation of its stability by high shear forces. After all the preceding high-speed and medium-speed stirring, the system may introduce new bubbles. Therefore, the remaining defoamer and infrared-reflecting filler are added at the end to effectively eliminate these bubbles generated during the process, preventing defects such as pinholes and fisheyes during application, resulting in a coating with excellent anti-condensation and thermal insulation properties.

[0055] The invention provided by the present invention will be further described in detail below through specific embodiments.

[0056] It should be noted that, unless otherwise specified, the raw materials used in the following embodiments can be obtained by commercial purchase or conventional methods, and the experimental methods without specific conditions are all conventional methods and conditions well known in the art.

[0057] In the following examples and comparative examples, the silicone-modified acrylic emulsion was UC-3300, purchased from Guangzhou Haoyi New Material Technology Co., Ltd.; the silica sol was purchased from Zhejiang Yuda Chemical Co., Ltd., with the brand name ZS-25; the defoamer used was silicone defoamer HY-709, purchased from Hubei Shiteng Chemical Technology Co., Ltd., with the product number 0213; and the leveling agent was an acrylic ester leveling agent of model BYK-385.

[0058] Example 1

[0059] The composition includes the following components by weight: 25 parts aerogel, 10 parts compound filler, 30 parts polymer emulsion, 10 parts infrared reflective filler, 5 parts dodecyl alcohol ester, 0.5 parts polyethylene glycol, 0.5 parts defoamer, 1 part leveling agent, and 15 parts deionized water.

[0060] The composite filler consists of vitrified microspheres and mica powder in a mass ratio of 1:1; the polymer emulsion consists of silicone-modified acrylic emulsion and silica sol in a mass ratio of 10:1.

[0061] The preparation process of the infrared reflective filler is as follows:

[0062] A titanium tetrachloride solution with a mass fraction of 45% was prepared, and antimony trichloride was added and mixed evenly. The molar ratio of Ti to Sb was 90:5. The titanium tetrachloride solution with a volume ratio of 1:1 was pyrolyzed with the aqueous solution at 100°C for 2 hours, and then aged for 6 hours. After filtration and drying, it was first calcined at 300°C for 2 hours, and then heated to 500°C for 2 hours. After cooling and pulverizing, antimony-doped rutile TiO2 nanoparticles were obtained.

[0063] Subsequently, antimony-doped rutile TiO2 nanoparticles were dispersed in a 40wt% ethanol aqueous solution to form a stable suspension. Then, poly(N-isopropylacrylamide) was added to the suspension to form a mixture. The mixture was stirred at room temperature for 2 hours, filtered, washed, and dried to obtain the infrared reflective filler. The mass ratio of antimony-doped rutile TiO2 nanoparticles to poly(N-isopropylacrylamide) was 1:0.5.

[0064] Preparation of anti-condensation coatings containing aerogel:

[0065] S1. Disperse silica aerogel in an aqueous acrylic emulsion with a mass concentration of 25%, wherein the mass ratio of the aqueous acrylic solution to the aerogel is 1:1. Stir at 300 r / min for 35 min and dry to obtain the aerogel for later use.

[0066] Mix deionized water, dispersant and 50% defoamer according to the mass fraction, stir at 300 rpm for 35 min, add the prepared aerogel, and stir thoroughly to completely wet the aerogel to obtain mixture A.

[0067] S2. Mix the polymer emulsion and the compound filler, disperse at 2000 rpm for 25 min, then add the film-forming aid and leveling agent, and continue to disperse at the same speed for 25 min to obtain mixture B.

[0068] S3. Add mixture A to mixture B and disperse at 800 rpm for 20 min. Then add the remaining 50% of defoamer and infrared reflective filler and stir for 25 min to obtain the anti-condensation coating containing aerogel.

[0069] Example 2

[0070] The composition includes the following components by weight: 35 parts aerogel, 15 parts compound filler, 40 parts polymer emulsion, 13 parts infrared reflective filler, 10 parts dodecyl alcohol ester, 0.7 parts polyethylene glycol, 1 part defoamer, 2 parts leveling agent, and 22 parts deionized water.

[0071] The composite filler consists of vitrified microspheres and mica powder in a mass ratio of 1:1; the polymer emulsion consists of silicone-modified acrylic emulsion and silica sol in a mass ratio of 10:1.

[0072] The preparation process of the infrared reflective filler is as follows:

[0073] A titanium tetrachloride solution with a mass fraction of 45% was prepared, and antimony trichloride was added and mixed evenly. The molar ratio of Ti to Sb was 90:5. The titanium tetrachloride solution with a volume ratio of 1:1 was pyrolyzed with the aqueous solution at 100°C for 2 hours, and then aged for 6 hours. After filtration and drying, it was first calcined at 300°C for 2 hours, and then heated to 500°C for 2 hours. After cooling and pulverizing, antimony-doped rutile TiO2 nanoparticles were obtained.

[0074] Subsequently, antimony-doped rutile TiO2 nanoparticles were dispersed in a 40wt% ethanol aqueous solution to form a stable suspension. Then, poly(N-isopropylacrylamide) was added to the suspension to form a mixture. The mixture was stirred at room temperature for 2-3 hours, filtered, washed, and dried to obtain the infrared reflective filler. The mass ratio of antimony-doped rutile TiO2 nanoparticles to poly(N-isopropylacrylamide) was 1:0.55.

[0075] Preparation of anti-condensation coatings containing aerogel:

[0076] S1. Disperse silica aerogel in an aqueous acrylic emulsion with a mass concentration of 25~35%, wherein the mass ratio of the aqueous acrylic solution to the aerogel is 1.5:1. Stir at 300 r / min for 40 min, and then dry to obtain the aerogel for later use.

[0077] Mix deionized water, dispersant and 50% defoamer according to the mass fraction, stir at 400 rpm for 40 min, add the prepared aerogel, and stir thoroughly to completely wet the aerogel to obtain mixture A.

[0078] S2. Mix the polymer emulsion and the compound filler, disperse at 2500 rpm for 35 min, then add the film-forming aid and leveling agent, and continue to disperse at the same speed for 30 min to obtain mixture B.

[0079] S3. Add mixture A to mixture B and disperse at 900 rpm for 30 min. Then add the remaining 50% of defoamer and infrared reflective filler and stir for 30 min to obtain the anti-condensation coating containing aerogel.

[0080] Example 3

[0081] The composition includes the following parts by weight: 50 parts aerogel, 25 parts compound filler, 50 parts polymer emulsion, 15 parts infrared reflective filler, 15 parts dodecyl alcohol ester, 1 part polyethylene glycol, 2 parts defoamer, 3 parts leveling agent, and 30 parts deionized water.

[0082] The composite filler consists of vitrified microspheres and mica powder in a mass ratio of 1:1; the polymer emulsion consists of silicone-modified acrylic emulsion and silica sol in a mass ratio of 10:1.

[0083] The preparation process of the infrared reflective filler is as follows:

[0084] A titanium tetrachloride solution with a mass fraction of 45% was prepared, and antimony trichloride was added and mixed evenly. The molar ratio of Ti to Sb was 90:5. The titanium tetrachloride solution with a volume ratio of 1:1 was pyrolyzed with the aqueous solution at 100°C for 2 hours, and then aged for 6 hours. After filtration and drying, it was first calcined at 300°C for 2 hours, and then heated to 500°C for 2 hours. After cooling and pulverizing, antimony-doped rutile TiO2 nanoparticles were obtained.

[0085] Subsequently, antimony-doped rutile TiO2 nanoparticles were dispersed in a 40 wt% ethanol aqueous solution to form a stable suspension. Then, poly(N-isopropylacrylamide) was added to the suspension to form a mixture. The mixture was stirred at room temperature for 3 hours, filtered, washed, and dried to obtain the infrared reflective filler. The mass ratio of antimony-doped rutile TiO2 nanoparticles to poly(N-isopropylacrylamide) was 1:0.6.

[0086] Preparation of anti-condensation coatings containing aerogel:

[0087] S1. Disperse silica aerogel in an aqueous acrylic emulsion with a mass concentration of 35%, wherein the mass ratio of the aqueous acrylic solution to the aerogel is 2:1. Stir at 300 r / min for 50 min and dry to obtain the aerogel for later use.

[0088] Mix deionized water, dispersant and 50% defoamer according to the mass fraction, stir at 500 rpm for 50 min, add the prepared aerogel, and stir thoroughly to completely wet the aerogel to obtain mixture A.

[0089] S2. Mix the polymer emulsion and the compound filler, disperse at 3000 rpm for 45 min, then add the film-forming aid and leveling agent, and continue to disperse at the same speed for 40 min to obtain mixture B;

[0090] S3. Add mixture A to mixture B and disperse at 1000 rpm for 40 min. Then add the remaining 50% of defoamer and infrared reflective filler and stir for 35 min to obtain the anti-condensation coating containing aerogel.

[0091] Comparative Example 1

[0092] Comparative Example 1 is basically the same as Example 1, except that the infrared reflective filler in this comparative example was not treated with poly-N-isopropylacrylamide.

[0093] Comparative Example 2

[0094] Comparative Example 2 is basically the same as Example 1, except that no infrared reflective filler was added in this comparative example.

[0095] Comparative Example 3

[0096] Comparative Example 3 is basically the same as Example 1, except that the aerogel in this comparative example was not treated with an aqueous acrylic solution.

[0097] Comparative Example 4

[0098] Comparative Example 4 is basically the same as Example 1, except that the composite filler in this comparative example is only vitrified microspheres.

[0099] Comparative Example 5

[0100] Comparative Example 5 is basically the same as Example 1, except that the compound filler in this comparative example is only mica powder.

[0101] Comparative Example 6

[0102] Comparative Example 6 is basically the same as Example 1, except that no compound filler was added in this comparative example.

[0103] Comparative Example 7

[0104] Comparative Example 7 is basically the same as Example 1, except that no silica sol was added in this comparative example.

[0105] Comparative Example 8

[0106] Comparative Example 8 is basically the same as Example 1, except that no aerogel was added in this comparative example.

[0107] Performance testing:

[0108] Using a building substrate material (cement mortar board, 100cm*100cm*5cm) as the test substrate, the coatings prepared in the examples and comparative examples were sprayed onto its surface, with a coating thickness of 3mm.

[0109] 1. Initial dew point and condensation amount: The test was conducted in accordance with the standard HG / T 4560-2013 "Test Method for Anti-condensation Performance of Coatings". The test time was 120 min. The temperature and humidity control chamber was 25±0.5℃ and the relative humidity was 95±3%. The temperature of the circulating water bath was 5±0.5℃.

[0110] 2. Thermal conductivity: The test results obtained according to standard GB / T 10296-2008 are shown in Table 1 below:

[0111] Table 1

[0112] Group First dew point / min Dew concentration / g Thermal conductivity W / (m·K) Example 1 84 2.4 0.029 Example 2 87 2.1 0.028 Example 3 85 2.3 0.029 Comparative Example 1 78 3.1 0.041 Comparative Example 2 69 4.2 0.053 Comparative Example 3 77 3.2 0.032 Comparative Example 4 75 3.5 0.039 Comparative Example 5 73 3.8 0.038 Comparative Example 6 62 5.9 0.058 Comparative Example 7 80 2.9 0.035 Comparative Example 8 50 8.1 0.066

[0113] As shown in Table 1, the coating prepared by this invention has a long initial dew point time and low condensation amount, indicating that it has good anti-condensation performance. Furthermore, according to standard HG / T 4560-2013, the bonding strengths of Examples 1-3 are 0.9MPa, 1.3MPa, and 1.1MPa, respectively, which can achieve the desired effect when the coating thickness is only 3mm. The coating prepared by this invention has a low thermal conductivity, which can achieve a heat preservation effect.

[0114] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. An anti-condensation coating containing aerogel, characterized in that, It comprises the following components by weight: 25-50 parts aerogel, 10-25 parts compound filler, 30-50 parts polymer emulsion, 10-15 parts infrared reflective filler, 5-15 parts film-forming aid, 0.5-1 part dispersant, 0.5-2 parts defoamer, 1-3 parts leveling agent, and 15-30 parts deionized water; The composite filler is vitrified microspheres and mica powder in a mass ratio of 1:1; the infrared reflective filler is antimony-doped rutile TiO2 that has undergone polyN-isopropylacrylamide surface treatment. The preparation process of the infrared reflective filler is as follows: A titanium tetrachloride solution with a mass fraction of 45% was prepared, and antimony trichloride was added and mixed evenly. The molar ratio of Ti to Sb was 90:

5. The titanium tetrachloride solution with a volume ratio of 1:1 was pyrolyzed with water at 100°C for 2 hours, and then aged for 6 hours. After filtration and drying, it was first calcined at 300°C for 2 hours, and then heated to 500°C for 2 hours. After cooling and pulverizing, antimony-doped rutile TiO2 nanoparticles were obtained. Subsequently, antimony-doped rutile TiO2 nanoparticles were dispersed in a 40wt% ethanol aqueous solution to form a stable suspension. Then, poly(N-isopropylacrylamide) was added to the suspension to form a mixture. The mixture was stirred at room temperature for 2-3 hours, filtered, washed, and dried to obtain the infrared reflective filler. The mass ratio of antimony-doped rutile TiO2 nanoparticles to poly(N-isopropylacrylamide) was 1:(0.5-0.6). The aerogel undergoes pretreatment before use, as follows: The aerogel was dispersed in an aqueous acrylic emulsion with a mass concentration of 25-35%, wherein the mass ratio of the aqueous acrylic solution to the aerogel was (1-2):

1. The mixture was stirred at 300 r / min for 35-50 min and then dried to obtain the aerogel for later use. The polymer emulsion is a silicone-modified acrylic emulsion and silica sol in a mass ratio of 10:

1.

2. The anti-condensation coating containing aerogel according to claim 1, characterized in that, The aerogel has an average particle size of 100 μm and is one or more of silica aerogel particles, titanium dioxide aerogel particles, zirconium dioxide aerogel particles, and aluminum oxide aerogel particles.

3. The anti-condensation coating containing aerogel according to claim 1, characterized in that, The defoamer is one or more of mineral oils, organosilicones, and polyethers.

4. The anti-condensation coating containing aerogel according to claim 1, characterized in that, The film-forming aid is one or more of the following: dodecyl alcohol ester, propylene glycol butyl ether, propylene glycol phenyl ether, ethylene glycol butyl ether acetate, and propylene glycol methyl ether acetate.

5. The anti-condensation coating containing aerogel according to claim 1, characterized in that, The dispersant is one or more of the following: polycarboxylate dispersants, polyacrylic acid, sodium polyacrylate, polyvinyl alcohol, and polyethylene glycol.

6. The anti-condensation coating containing aerogel according to claim 1, characterized in that, The leveling agent is a silicone-based leveling agent or an acrylate-based leveling agent.

7. A preparation process for an anti-condensation coating containing aerogel as described in any one of claims 1-6, characterized in that, Includes the following steps: S1. According to the mass fraction, mix deionized water, dispersant and 50% defoamer, stir at 300~500 rpm for 35~50 min, add the prepared aerogel, stir thoroughly to make the aerogel completely liquid wetted to obtain mixture A. S2. Mix the polymer emulsion and the compound filler, disperse at a speed of 2000~3000 rpm for 25~45 min, add film-forming aid and leveling agent, and continue to disperse at the same speed for 25~40 min to obtain mixture B; S3. Add mixture A to mixture B and disperse at 800-1000 rpm for 20-40 minutes. Then add the remaining 50% of defoamer and infrared reflective filler and stir for 25-35 minutes to obtain the anti-condensation coating containing aerogel.