A bidirectional thermal management coating system for high altitude concrete and a method of making the same

Abstract

The application discloses a bidirectional thermal management coating system for highland concrete and a preparation method thereof, relates to the technical field of concrete structure protection, and the bidirectional thermal management coating system is arranged on the surface of a concrete base material and sequentially comprises an interface sealing primer layer, an aerogel thermal resistance buffer layer and a high-reflection low-emissivity surface layer from inside to outside. The dry film thickness of the interface sealing primer layer is 20-80 mu m, the dry film thickness of the aerogel thermal resistance buffer layer is 0.8-3.0 mm, and the dry film thickness of the high-reflection low-emissivity surface layer is 80-250 mu m. The interface sealing primer layer, the aerogel thermal resistance buffer layer with a low thermal conductivity and the high-reflection low-emissivity surface layer are arranged to form an interface sealing-thermal resistance buffer-spectrum selection coupling structure. Under the synergistic effect of the three-layer coating structure, the daily temperature amplitude of the concrete surface can be significantly reduced, and the risk of concrete cracking caused by temperature gradient and temperature fatigue can be reduced from the thermal boundary source.

Description

Technical Field

[0001] This invention relates to the field of concrete structure protection technology, specifically to a two-way thermal management coating system for high-altitude concrete and its preparation method. Background Technology

[0002] High-altitude regions experience strong solar radiation, thin air, and large diurnal temperature variations. Concrete has a low solar reflectivity (0.20-0.35), causing exposed concrete structures to heat up rapidly during the day due to short-wave solar radiation and high infrared emissivity (approximately 0.85-0.95). At night, it cools rapidly due to long-wave solar radiation and convective heat transfer. Engineering measurements show that the daily temperature fluctuation of concrete surfaces on high-altitude regions is large, reaching 40-55 °C. This creates a significant unsteady temperature gradient between the concrete surface and interior, leading to repeated tensile and compressive stress cycles under constrained conditions. This easily induces temperature fatigue cracking, surface spalling, and reduced durability. Therefore, simultaneously reducing the peak daytime temperature rise, increasing the trough nighttime temperature drop, compressing the daily temperature fluctuation, and weakening the internal temperature gradient are crucial for thermal stress protection of concrete on high-altitude regions.

[0003] In existing technologies, thermal protection materials for building and concrete exterior surfaces mainly fall into four categories: aerogel thermal insulation coatings, white reflective thermal insulation coatings, radiative cooling coatings, and low infrared emissivity coatings. Aerogel thermal insulation coatings typically utilize silica aerogel and hollow fillers to reduce thermal conductivity; white reflective thermal insulation coatings typically utilize rutile titanium dioxide, barium sulfate, or zinc oxide to increase solar reflectivity; radiative cooling coatings typically aim for both high solar reflectivity and high emissivity within an 8-13 μm atmospheric window; and low infrared emissivity coatings typically reduce infrared emissivity using aluminum powder, metallic pigments, or metallized fillers. These technologies address conductive insulation, daytime reflective cooling, radiative cooling, or low infrared emissivity issues respectively, but none of them incorporate a coupled design to address the engineering goals of "daytime peak reduction, nighttime valley enhancement, and compression of daily temperature amplitude" for high-altitude concrete.

[0004] In addition, while existing white reflective heat insulation coatings can reduce peak daytime temperatures, they typically have high infrared emissivity and strong heat dissipation at night; radiative cooling coatings emphasize high emissivity through an 8-13 μm atmospheric window, making them suitable for daytime heat dissipation, but they may further reduce the temperature trough at night on plateaus; aerogel heat insulation coatings can reduce thermal conductivity, but without solar reflection and infrared emissivity regulation, it is difficult to control the temperature at both ends of the day and night; low infrared emissivity coatings are mostly used for infrared stealth or industrial energy conservation, and usually do not take into account the rough and porous concrete substrate and the thermal stress fatigue conditions on plateaus.

[0005] In summary, existing single-function concrete protective coatings cannot simultaneously address the opposing needs of "reducing daytime temperature rise peaks" and "suppressing excessive nighttime cooling," thus failing to achieve the goal of compressing daily temperature fluctuations and weakening internal temperature gradients. Therefore, this paper presents a bidirectional thermal management coating system for high-altitude concrete and its preparation method to solve the aforementioned problems. Summary of the Invention

[0006] This invention addresses the technical problem that existing high-altitude concrete protection systems cannot simultaneously reduce daytime temperature peaks, increase nighttime temperature troughs, compress daily temperature amplitude, and weaken internal temperature gradients. The aim is to provide a bidirectional thermal management coating system for high-altitude concrete and its preparation method. This system achieves low infrared emissivity while maintaining high solar reflectivity by using a high-reflectivity, low-emissivity surface layer; reduces residual heat flow into the concrete during the day and slows down nighttime heat loss by using a low-thermal-conductivity aerogel thermal resistance buffer layer; and improves the adhesion and durability of the coating system by using an interface-sealing primer layer. This forms a coupled structure of "interface sealing-thermal resistance buffering-spectral selection." The synergistic effect of the three coating layers significantly reduces the daily temperature amplitude of the concrete surface, mitigating the risk of concrete cracking caused by temperature gradients and temperature fatigue at the source of thermal degradation.

[0007] This invention is achieved through the following technical solution:

[0008] The first objective of this invention is to provide a bidirectional thermal management coating system for high-altitude concrete, wherein the bidirectional thermal management coating system is disposed on the surface of a concrete substrate and comprises, from the inside out, an interface sealing primer layer, an aerogel thermal resistance buffer layer, and a high-reflectivity, low-emissivity surface layer.

[0009] The interface sealing primer layer comprises, by weight, 40-70 parts of film-forming resin, 0-15 parts of penetrating silane or siloxane, 20-55 parts of water or environmentally friendly diluent, 0.1-1 parts of wetting agent, and 0.1-1 parts of defoamer.

[0010] The aerogel thermal resistance buffer layer comprises, by weight: 8-25 parts silica aerogel powder, 5-20 parts low thermal conductivity hollow filler, 30-60 parts weather-resistant polymer binder, 0.2-2 parts thickener, 0.2-2 parts dispersant, 0.1-1 parts defoamer, and 10-35 parts water or environmentally friendly diluent.

[0011] The high-reflectivity, low-emissivity surface layer comprises, by weight: 5-18 parts coated flake aluminum powder, 15-45 parts high-refractive-index filler, 35-65 parts weather-resistant film-forming resin, 0.2-2 parts coupling agent, 0.1-1.5 parts leveling and orientation aid, 0.2-2 parts dispersant, and 10-35 parts diluent or water.

[0012] This invention employs an interface-sealing primer layer on the surface of a concrete substrate to seal the capillary pores of the concrete surface, reduce the water absorption rate of the concrete base layer, and improve the adhesion between the coating system and the concrete substrate. An aerogel thermal resistance buffer layer is then applied to the surface of the interface-sealing primer layer to reduce the heat transfer rate between the coating system and the concrete substrate. This is achieved through the synergistic use of silica aerogel powder and low thermal conductivity hollow fillers, resulting in a thermal conductivity as low as 0.028-0.045 W / (m·K). This delays heat transfer into the concrete interior during the day and blocks heat diffusion to the outside of the concrete at night. A high-reflectivity, low-emissivity surface layer is applied to the outermost layer, with high-refractive-index fillers used to create multi-scale scattering in the 0.3-2.5 μm solar wavelength range, improving the weighted average reflectivity of the solar wavelength range. Flake-shaped aluminum powder is coated to reduce the reflectivity by 2.5-25 μm. The emissivity in the μm infrared band is enhanced by using leveling and orientation additives and the construction leveling process to form an orientation structure parallel or nearly parallel to the coating surface. The directional arrangement of coated flake aluminum powder and high refractive index fillers of different particle sizes work together to form a multi-scale scattering and low infrared emission structure, so that the weighted average reflectivity in the 0.3-2.5 μm solar band is not less than 0.90, the average emissivity in the 2.5-25 μm infrared band is 0.25-0.45, and the average emissivity in the 8-13 μm atmospheric window is not higher than 0.50. High solar reflection during the day reduces heat input, and low infrared radiation at night reduces heat loss.

[0013] Therefore, the three-layer coating on the concrete substrate of this invention forms a coupled structure of "interface sealing-thermal resistance buffering-spectral selection". Under the synergistic effect of the three-layer coating structure, the daily temperature amplitude of the concrete surface can be significantly reduced, which has direct engineering significance for reducing the risk of temperature fatigue cracking of concrete in high-altitude areas. It is suitable for the protection of concrete structures such as bridge piers, bridge decks, highway pavements, tunnel entrances, dam faces, water conveyance structures, reservoirs, canal linings or building exterior walls in high-altitude areas.

[0014] Furthermore, the film-forming resin in the interface sealing primer layer is one or more of waterborne epoxy resin, silane-modified resin, and organosilicon-modified acrylic resin.

[0015] Furthermore, the dry film thickness of the interface sealing primer layer is 20-80 μm.

[0016] Furthermore, the silica aerogel powder has a particle size D50 of 5-80 μm, a porosity of not less than 85%, and a surface that has undergone hydrophobic modification treatment; the low thermal conductivity hollow filler is one or more of hollow glass microspheres, ceramic hollow microspheres, and closed-cell expanded perlite micro powder; the weather-resistant polymer binder is one or more of silicone acrylic emulsion, organosilicon resin, waterborne fluorocarbon resin, and aliphatic polyurethane emulsion.

[0017] Furthermore, the dry film thickness of the aerogel thermal resistance buffer layer is 0.8-3.0 mm.

[0018] Furthermore, the aspect ratio of the coated flake aluminum powder is 20-100, and the average flake diameter is 5-40 μm; the surface coating layer of the coated flake aluminum powder is one or more of silicon dioxide, aluminum oxide, silane coupling agent coating layer, and acrylic resin coating layer.

[0019] Further, the high refractive index filler comprises rutile titanium dioxide, barium sulfate, zinc oxide and / or aluminum oxide, wherein the rutile titanium dioxide comprises 8-25 parts by mass and has an average particle size D50 of 0.15-0.50 μm; the barium sulfate comprises 5-20 parts by mass and has an average particle size D50 of 0.3-2.0 μm; and the zinc oxide and / or aluminum oxide comprises 0-5 parts by mass.

[0020] Furthermore, the weather-resistant film-forming resin in the high-reflectivity, low-emissivity surface layer is one or more of the following: silicone resin, fluorocarbon resin, silicone-acrylic emulsion, and aliphatic polyurethane resin.

[0021] Furthermore, the dry film thickness of the high-reflectivity, low-emissivity surface layer is 80-250 μm.

[0022] The second objective of this invention is to provide a method for preparing a two-way thermal management coating system for high-altitude concrete, characterized by comprising the following steps:

[0023] S1. Concrete substrate pretreatment: This includes cleaning, grinding, dust removal, and defect repair of the concrete substrate surface.

[0024] S2. Preparation of interface sealing primer layer: Prepare slurry according to the formula of interface sealing primer layer in claim 1, apply it to the surface of pretreated concrete substrate, and form interface sealing primer layer after curing.

[0025] S3. Preparation of aerogel thermal resistance buffer layer: Prepare a slurry according to the formulation of aerogel thermal resistance buffer layer in claim 1, apply it to the surface of interface sealing primer layer, and form aerogel thermal resistance buffer layer after curing.

[0026] S4. Preparation of high-reflectivity, low-emissivity surface layer: Prepare a slurry according to the formula of the high-reflectivity, low-emissivity surface layer in claim 1, apply it to the surface of the aerogel thermal resistance buffer layer, and form a high-reflectivity, low-emissivity surface layer after curing.

[0027] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0028] This invention aims to reduce the daily temperature amplitude of concrete, unlike traditional radiative cooling coatings that simply pursue high emissivity of 8-13μm. This avoids excessive radiative cooling at night in high-altitude areas. By setting a high-reflectivity, low-emissivity surface layer, and utilizing high-refractive-index fillers and coated flake aluminum powder in synergy, it achieves low infrared emissivity while maintaining high solar reflectivity. By placing a low-thermal-conductivity aerogel thermal resistance buffer layer below the low-emissivity surface layer, surface spectral modulation and internal thermal resistance buffering work synergistically to reduce residual heat flow into the concrete during the day and slow down internal heat loss at night. By setting an interface-sealing primer layer to adapt to the rough, porous, and absorbent concrete substrate, it improves the adhesion and durability of the coating system. This forms a coupled structure of "interface sealing-thermal resistance buffering-spectral selection". Under the synergistic effect of the three-layer coating structure, it can significantly reduce the daily temperature amplitude of the concrete surface, reducing the risk of concrete cracking caused by temperature gradient and temperature fatigue from the source of thermal boundary. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:

[0030] Figure 1 This is a schematic diagram of the layered structure of the bidirectional thermal management coating system of the present invention.

[0031] Figure 2 This is a flowchart illustrating the preparation process of the bidirectional thermal management coating system of the present invention.

[0032] Figure 3 This is a schematic diagram of the day-night temperature variation curves of the uncoated concrete surface in Embodiment 2 of the present invention. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0034] Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. However, unnecessary details may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions may be omitted. This is to avoid making the following description unnecessarily lengthy and to facilitate understanding by those skilled in the art.

[0035] The "scope" disclosed in this invention is defined in the form of a lower limit and an upper limit. A given scope is defined by selecting a lower limit and an upper limit, which define the boundaries of the specific scope. The scope defined in this way can include or exclude end values, and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a scope.

[0036] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions.

[0037] Unless otherwise specified, all technical features and optional technical features of this invention can be combined to form new technical solutions.

[0038] Unless otherwise specified, the terms "comprising" and "including" as used in this invention can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other substances not listed may also be included, or that only the listed substances may be included.

[0039] Unless otherwise specified, all steps of the present invention may be performed sequentially or randomly, but are preferably performed sequentially.

[0040] This invention addresses the technical problem that existing high-altitude concrete protection systems cannot simultaneously reduce daytime temperature peaks, increase nighttime temperature valleys, compress daily temperature amplitude, and weaken internal temperature gradients. It provides a bidirectional thermal management coating system for high-altitude concrete and its preparation method. This invention uses compressing the daily temperature amplitude of the concrete surface as the core control index, while simultaneously achieving daytime peak reduction, nighttime valley enhancement, and weakening of internal temperature gradients.

[0041] In a first aspect, this invention constructs a surface thermal boundary bidirectional control coating system based on the coupling of "interface sealing-thermal resistance buffering-spectral selection". The bidirectional thermal management coating system is disposed on the surface of a concrete substrate and, from the inside out, comprises an interface sealing primer layer, an aerogel thermal resistance buffering layer, and a high-reflectivity, low-emissivity surface layer; the structure is as follows: Figure 1 As shown.

[0042] As one specific implementation, the interface sealing primer layer comprises, by weight: 40-70 parts of film-forming resin, 0-15 parts of penetrating silane or siloxane, 20-55 parts of water or environmentally friendly diluent, 0.1-1 parts of wetting agent, and 0.1-1 parts of defoamer; the film-forming resin is one or more of waterborne epoxy resin, silane-modified resin, or organosilicon-modified acrylic resin.

[0043] The interface sealing primer layer of the present invention is applied to the surface of a concrete substrate to seal the capillary pores of the concrete surface, reduce the water absorption rate of the concrete base layer, and improve the adhesion between the coating system and the concrete substrate. It uses a high weather-resistant resin and penetrating components to seal the capillary pores of the concrete and improve the adhesion. The tensile bond strength with the concrete substrate is not less than 1.5 MPa, and the water absorption rate reduction rate is not less than 40%, so that the functional layer is adapted to the rough and porous concrete substrate.

[0044] In one specific embodiment, the aerogel thermal resistance buffer layer comprises, by weight: 8-25 parts silica aerogel powder, 5-20 parts low thermal conductivity hollow filler, 30-60 parts weather-resistant polymer binder, 0.2-2 parts thickener, 0.2-2 parts dispersant, 0.1-1 parts defoamer, and 10-35 parts water or environmentally friendly diluent. Specifically, the silica aerogel powder has a particle size D50 of 5-80 μm, a porosity of not less than 85%, and a surface that has undergone hydrophobic modification treatment (commercially available silica aerogel powder treated with hexamethyldisilazane); the low thermal conductivity hollow filler is one or more of hollow glass microspheres, ceramic hollow microspheres, and closed-cell expanded perlite micropowder; the weather-resistant polymer binder is one or more of silicone-acrylic emulsion, organosilicon resin, waterborne fluorocarbon resin, or aliphatic polyurethane emulsion.

[0045] The aerogel thermal resistance buffer layer of the present invention is disposed on the surface of the interface sealing primer layer to reduce the heat transfer rate between the coating system and the concrete substrate. It uses silica aerogel powder and low thermal conductivity hollow filler in synergy, with a thermal conductivity as low as 0.028-0.045 W / (m·K). During the day, it delays the heat transfer to the interior of the concrete and at night, it blocks the heat diffusion to the exterior of the concrete.

[0046] In one specific implementation, the high-reflectivity, low-emissivity surface layer comprises, by weight: 5-18 parts of coated flake aluminum powder, 15-45 parts of high-refractive-index filler, 35-65 parts of weather-resistant film-forming resin, 0.2-2 parts of coupling agent, 0.1-1.5 parts of leveling and orientation aid, 0.2-2 parts of dispersant, and 10-35 parts of diluent or water.

[0047] Specifically, the aspect ratio of the coated flake aluminum powder is 20-100, the average flake diameter is 5-40 μm, and the surface coating layer is one or more of silica, alumina, silane coupling agent or acrylic resin coating layer; the coated flake aluminum powder is oriented in a parallel or approximately parallel manner to the coating surface in the cured high reflectivity and low emissivity surface layer.

[0048] The high-refractive-index filler comprises rutile titanium dioxide and barium sulfate, and may further comprise one or more of zinc oxide and aluminum oxide. Wherein, provided the total mass fraction of the high-refractive-index filler is 15-45 parts, the mass fraction of the rutile titanium dioxide is 8-25 parts, with an average particle size D50 of 0.15-0.50 μm; the mass fraction of the barium sulfate is 5-20 parts, with an average particle size D50 of 0.3-2.0 μm; and the mass fraction of the zinc oxide and / or aluminum oxide is 0-5 parts. The preferred mass ratio of the high-refractive-index filler to the coated flake aluminum powder is 1.5:1-5:1. The weather-resistant film-forming resin is one or more of silicone resin, fluorocarbon resin, silicone-acrylic emulsion, and aliphatic polyurethane resin.

[0049] The high-reflectivity, low-emissivity surface layer of this invention is disposed on the outside of the aerogel thermal resistance buffer layer. It provides high reflectivity in the solar band and controlled low emissivity in the infrared band. High-refractive-index filler is used to form multi-scale scattering in the 0.3-2.5 μm solar band, increasing the weighted average reflectivity of that band. Coated flake aluminum powder is used to reduce emissivity in the 2.5-25 μm infrared band. Through leveling and orientation aids and the construction leveling process, an orientation structure parallel or approximately parallel to the coating surface is formed. Therefore, by utilizing the directional arrangement of the coated flake aluminum powder and the synergistic effect of high-refractive-index filler with different particle sizes to form a multi-scale scattering and low infrared emission structure, the weighted average reflectivity in the 0.3-2.5 μm solar band is not less than 0.90, the average emissivity in the 2.5-25 μm infrared band is 0.25-0.45, and the average emissivity in the 8-13 μm atmospheric window is not higher than 0.50. This achieves high solar reflection during the day to reduce heat input and low infrared radiation at night to reduce heat loss.

[0050] Based on the above-mentioned bidirectional thermal management coating system, simulation tests were conducted under high-altitude day-night cycles. The results showed that the bidirectional thermal management coating system reduced the daily temperature amplitude by no less than 50% under simulated high-altitude day-night cycles (the daily temperature amplitude is the difference between the highest and lowest temperatures on the concrete surface within 24 hours). This proves that the bidirectional thermal management coating system of this invention, when used on exposed concrete structures in high-altitude areas, can significantly reduce the daily temperature amplitude of the concrete surface through the synergistic effect of the three-layer structure. It is suitable for the protection of concrete structures such as bridge piers, bridge decks, highway pavements, tunnel entrances, dam faces, water conveyance structures, reservoirs, canal linings, or building exterior walls in high-altitude areas.

[0051] Secondly, the present invention also provides a method for preparing the bidirectional thermal management coating system, such as... Figure 2 As shown, it includes the following steps:

[0052] S1. Concrete substrate pretreatment

[0053] The concrete substrate surface is cleaned, ground, dusted, and defect-repaired to remove surface laitance, oil, loose particles, and other adhering substances that may affect adhesion, ensuring a firm, smooth, and dry surface. The surface moisture content is controlled to be no higher than 8%, with no standing water, obvious efflorescence, or loose, powdery areas. For honeycomb, pitted, cracked, porous, or locally loose areas, cement-based or polymer-based repair materials are used for repair and curing until stable. This treatment provides the concrete substrate surface with the wetting, penetration, and adhesion conditions for an interface-sealing primer layer, providing a stable base layer for the subsequent aerogel thermal resistance buffer layer and high-reflectivity, low-emissivity topcoat.

[0054] S2, Preparation of Interface Sealing Primer Layer

[0055] After thoroughly mixing the interface sealing primer according to the formula, apply it to the pretreated concrete substrate surface using a roller, brush, or spray method, ensuring the primer fully wets and penetrates into the capillaries of the concrete surface. The application of the interface sealing primer should be continuous and uniform, without any omissions. For areas with rapid absorption or high porosity, apply additional coating to ensure complete sealing of the concrete surface pores. After curing at room temperature, the interface sealing primer forms a dry film layer with a thickness of 20-80 μm. This interface sealing primer layer reduces the water absorption rate of the concrete substrate, improves interlayer adhesion, and inhibits the rapid absorption of the liquid phase components in the subsequent aerogel insulation grout by the concrete.

[0056] S3, Preparation of Aerogel Thermal Resistance Buffer Layer

[0057] A weather-resistant polymer binder, dispersant, defoamer, and water or environmentally friendly diluent are mixed evenly to form a continuous liquid phase system. Low thermal conductivity hollow filler and silica aerogel powder are then added and dispersed at a low speed. Finally, a thickener is added to adjust the rheological properties for application, resulting in an aerogel insulation slurry. The low-speed dispersion reduces damage to the porous structure of the silica aerogel and the shell structure of the low thermal conductivity hollow filler, ensuring the aerogel insulation slurry maintains low thermal conductivity after curing. The application viscosity of the aerogel insulation slurry is 8000-60000 mPa·s. After the interface sealing primer layer reaches a recoatable state, the aerogel insulation slurry is applied to the surface of the interface sealing primer layer using a scraper, spray, or roller coating method. The wet film thickness per coat is controlled at 0.5-1.5 mm, and 1-3 coats are applied. Each subsequent coat should be applied after the previous coat is surface dry and capable of supporting the next coating. After all construction is completed and cured, an aerogel thermal resistance buffer layer with a dry film thickness of 0.8-3.0 mm is formed.

[0058] S4, Preparation of High-Reflectivity, Low-Emissivity Surface Layer

[0059] A high-refractive-index filler, weather-resistant film-forming resin, coupling agent, dispersant, and diluent or water are uniformly mixed and dispersed to form a high-reflectivity filler dispersion system. Subsequently, coated flake aluminum powder and leveling and orienting agents are added and stirred at low speed to obtain a high-reflectivity, low-emissivity topcoat. The high-refractive-index filler is used to form multi-scale scattering in the 0.3-2.5 μm solar band, improving the weighted average reflectivity of the solar band. The coated flake aluminum powder is used to reduce the emissivity in the 2.5-25 μm infrared band and, through the leveling and orienting agents and the application leveling process, forms an orientation structure parallel or approximately parallel to the coating surface. The coated flake aluminum powder is not subjected to prolonged high-speed dispersion after addition to avoid damage to the flake structure, reduction in aspect ratio, or decrease in orientation capability. The application viscosity of the high-reflectivity, low-emissivity topcoat is 15-35 s, measured using a Ford cup (French cup 4). After the aerogel thermal resistance buffer layer reaches a recoatable state, the high-reflectivity, low-emissivity topcoat is applied to the surface of the aerogel thermal resistance buffer layer by spraying or roller coating. When using spraying, the spraying pressure should be controlled at 0.3-0.6 MPa, and the spraying distance at 150-300 mm. The high-reflectivity, low-emissivity topcoat is applied in 2-3 coats, with each coat having a dry film thickness of 30-80 μm. Each subsequent coat is applied after the previous coat has surface-dried. During the final coat application, the coating direction should be consistent or a light leveling treatment should be performed to promote the parallel or near-parallel orientation of the coated flake aluminum powder along the coating surface. After curing, a high-reflectivity, low-emissivity topcoat with a dry film thickness of 80-250 μm is formed.

[0060] The technical solution of the present invention will be further described in detail below with reference to the embodiments.

[0061] It should be noted that, unless otherwise specified, the experimental methods used in the embodiments are conventional methods. Unless otherwise specified, the materials, reagents, methods, and instruments used are all conventional materials, reagents, methods, and instruments in the art, and can be obtained commercially by those skilled in the art.

[0062] Example 1

[0063] A method for preparing a two-way thermal management coating system for high-altitude concrete includes the following steps:

[0064] S1. Concrete substrate pretreatment

[0065] The surface of the concrete substrate (300 mm × 300 mm × 50 mm C40 concrete slab) is cleaned, ground, dusted, and defect-repaired to remove surface laitance, oil, loose particles, and other adhering substances that may affect adhesion, ensuring the concrete surface is firm, smooth, and dry. The surface moisture content is controlled to be no higher than 8%, with no standing water, obvious efflorescence, or loose, powdery areas. For honeycomb, pitted, cracked, porous, or locally loose areas, cement-based or polymer-based repair materials are used for repair and cured until stable. This treatment provides the concrete substrate surface with the wetting, penetration, and adhesion conditions for the interface-sealing primer layer, providing a stable base layer for the subsequent aerogel thermal resistance buffer layer and high-reflectivity, low-emissivity topcoat.

[0066] S2, Preparation of Interface Sealing Primer Layer

[0067] The mixture comprises, by weight, 45 parts waterborne epoxy resin, 15 parts waterborne epoxy curing agent, 5 parts penetrating silane, 24 parts deionized water, 0.5 parts polyether-modified silicone wetting agent, and 0.5 parts polyether-modified silicone defoamer, wherein the mass ratio of waterborne epoxy resin to waterborne epoxy curing agent is 3:1. Before application, the waterborne epoxy resin, penetrating silane, wetting agent, defoamer, and deionized water are mixed thoroughly. Then, the waterborne epoxy curing agent is added and stirred until homogeneous. The mixture is applied using a roller coating method. After curing at room temperature, a 40 μm thick interface sealing primer layer is formed.

[0068] S3, Preparation of Aerogel Thermal Resistance Buffer Layer

[0069] The aerogel thermal resistance buffer layer formulation is as follows: 15 parts hydrophobic silica aerogel powder, 12 parts hollow glass microspheres, 45 parts silicone-acrylic emulsion, 0.8 parts ammonium polyacrylate dispersant, 0.6 parts cellulose thickener, 0.3 parts polyether-modified silicone defoamer, and 26.3 parts water. After mixing, an aerogel thermal insulation slurry with an application viscosity of approximately 25000 mPa·s is obtained. It is applied in two coats, with a total dry film thickness of 1.5 mm and a measured thermal conductivity of 0.036 W / (m·K).

[0070] S4, Preparation of High-Reflectivity, Low-Emissivity Surface Layer

[0071] The high-reflectivity, low-emissivity surface layer formulation is as follows: 10 parts silica-coated flake aluminum powder, 18 parts rutile titanium dioxide, 12 parts precipitated barium sulfate, 45 parts silicone-modified acrylic resin, 0.6 parts DPNB dipropylene glycol butyl ether (leveling and orientation aid), 0.8 parts KH570 silane coupling agent, 0.6 parts ammonium polyacrylate dispersant, and 13 parts propylene glycol methyl ether acetate diluent. Two coats are applied, resulting in a dry film thickness of 150 μm.

[0072] The test results after curing were as follows: solar reflectance of 0.93 in the 0.3-2.5 μm range and average infrared emissivity of 0.36 in the 2.5-25 μm range. In the day-night cycle test, the highest surface temperature after coating was 40.9 ℃, the lowest temperature was 19.2 ℃, the daily amplitude was 21.7 ℃, and the daily amplitude reduction rate was 56.9%.

[0073] Example 2

[0074] This embodiment is basically the same as Embodiment 1, except that: the thickness of the aerogel thermal resistance buffer layer is 2.2 mm, the amount of silica aerogel powder is 20 parts, the amount of hollow glass microspheres is 10 parts, and the thermal conductivity is 0.032 W / (m·K); the high reflectivity and low emissivity surface layer is coated with 12 parts of flake aluminum powder, 20 parts of rutile titanium dioxide, 10 parts of barium sulfate, and the dry film thickness is 180 μm.

[0075] The tests yielded a solar reflectance of 0.94 and an average infrared emissivity of 0.32 in the 2.5-25 μm range. During the diurnal cycle, the highest surface temperature was 39.8 ℃, the lowest was 20.1 ℃, the daily amplitude was 19.7 ℃, and the daily amplitude reduction rate was 60.9%.

[0076] Example 3

[0077] The process is basically the same as in Example 1, except that the high-reflectivity, low-emissivity surface layer uses water-based fluorocarbon resin as the film-forming resin, and the coating consists of 8 parts of flake aluminum powder, 22 parts of rutile titanium dioxide, 5 parts of zinc oxide, 8 parts of barium sulfate, and a dry film thickness of 130 μm.

[0078] The tests showed a solar reflectance of 0.95 and an average infrared emissivity of 0.40 in the 2.5-25 μm range. After 500 h of UV aging, the solar reflectance remained at 0.92, and the average infrared emissivity was 0.42. During the diurnal cycle, the highest surface temperature was 41.5 ℃, the lowest was 18.8 ℃, the daily amplitude was 22.7 ℃, and the daily amplitude reduction rate was 54.9%.

[0079] Comparative Example 1: Uncoated concrete

[0080] Use C40 concrete slabs of the same size, without any coating treatment.

[0081] During the day-night cycle test, the highest surface temperature was 60.8 ℃, the lowest temperature was 10.4 ℃, and the daily amplitude was 50.4 ℃.

[0082] Comparative Example 2: Ordinary white reflective heat insulation coating

[0083] Using the same C40 concrete slab as in Example 1, after pretreatment, the coating consisted of a conventional silicone-acrylic white reflective heat-insulating coating, comprising 45 parts silicone-acrylic emulsion, 8 parts rutile titanium dioxide, 20 parts precipitated barium sulfate, 5 parts zinc oxide, 13.2 parts water, 0.8 parts ammonium polyacrylate dispersant, 0.5 parts hydroxyethyl cellulose thickener, 0.3 parts polyether-modified silicone defoamer, and 0.2 parts polyether-modified silicone wetting agent. The dry film thickness was 200 μm. Tests showed a solar reflectance of 0.89 and an average infrared emissivity of 0.88 in the 2.5-25 μm range. During the day-night cycle, the highest surface temperature was 43.6 ℃, the lowest was 7.9 ℃, and the daily amplitude was 35.7 ℃. This comparative example showed significant cooling during the day, but at night, due to the high infrared emissivity, the surface temperature trough was lower than that of the uncoated concrete, and a large daily temperature amplitude still existed.

[0084] Comparative Example 3: Single Aerogel Thermal Resistance Buffer Layer

[0085] The same C40 concrete slab as in Example 1 was used, and the same substrate pretreatment and interface sealing primer layer application were performed sequentially. Only the same aerogel thermal resistance buffer layer as in Example 1 was applied over the interface sealing primer layer, but no high-reflectivity, low-emissivity topcoat was applied.

[0086] The tests yielded a solar reflectance of 0.76, an average infrared emissivity of 0.84 in the 2.5-25 μm range, and a thermal conductivity of 0.036 W / (m·K). During the diurnal cycle, the highest surface temperature was 49.2 ℃, the lowest was 13.6 ℃, and the diurnal temperature range was 35.6 ℃. This comparative model can reduce conductive heat flux to some extent, but due to insufficient solar reflectance, high infrared emissivity, and limited temperature range compression effect, its effectiveness is limited.

[0087] Comparative Example 4: Single high-reflectivity, low-emissivity surface layer

[0088] The same C40 concrete slab as in Example 1 was used, and the same substrate pretreatment and interface sealing primer layer were applied sequentially. Only a high-reflectivity, low-emissivity topcoat, the same as in Example 1, was applied over the interface sealing primer layer, but no aerogel thermal resistance buffer layer was applied.

[0089] The tests yielded a solar reflectance of 0.93 and an average infrared emissivity of 0.36 in the 2.5–25 μm range. During the diurnal cycle, the highest surface temperature was 44.1 ℃, the lowest was 18.5 ℃, and the diurnal amplitude was 25.6 ℃. This comparative analysis indicates that the high-reflectivity, low-emissivity surface layer can reduce nighttime radiative heat loss; however, due to the lack of a low-thermal-conductivity, thermally-resistance buffer layer, residual heat flow during the day can still easily penetrate into the concrete interior.

[0090] Comparative Example 5: Window High Emissivity Cooling Coating

[0091] The coating employs a porous PVDF-HFP / silica microsphere radiation cooling coating, using the same C40 concrete slab as in Example 1, and pre-treating the substrate and applying the interface sealing primer according to the method described in Example 1. The porous radiation cooling topcoat comprises, by weight, 20 parts of polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), 30 parts of silica microspheres with an average particle size D50 of 5-15 μm, 35 parts of acetone, and 15 parts of N,N-dimethylacetamide. First, PVDF-HFP is added to a mixed solvent of acetone and N,N-dimethylacetamide and stirred until completely dissolved. Then, the silica microspheres are added and dispersed at a low speed. The resulting slurry is sprayed three times onto the surface of the interface sealing primer layer, utilizing solvent evaporation to induce the formation of a porous structure. After complete curing, the porous PVDF-HFP / silica microsphere radiation cooling topcoat is formed. The dry film thickness is 250 μm, with a solar reflectivity of 0.94, an emissivity of 0.93 in the 8-13 μm window, and an average infrared emissivity of 0.86 in the 2.5-25 μm range. During the diurnal cycle, the highest surface temperature was 38.9 ℃, the lowest was 6.8 ℃, and the daily amplitude was 32.1 ℃. This comparative example shows a relatively low peak daytime temperature, but excessive radiative cooling at night significantly reduces the temperature trough, making it unsuitable for high-altitude concrete surface protection aimed at reducing temperature fatigue.

[0092] Comparative Example 6: Single Rutile Titanium Dioxide Filler System

[0093] This comparative example is the same as Example 3, using the same C40 concrete slab and sequentially applying an interface-sealing primer layer, an aerogel thermal resistance buffer layer, and a high-reflectivity, low-emissivity topcoat. The only difference is that the high-refractive-index filler uses only rutile titanium dioxide, without adding barium sulfate, zinc oxide, and aluminum oxide. The 22 parts of rutile titanium dioxide, 5 parts of zinc oxide, and 8 parts of barium sulfate in the topcoat of Example 3 are replaced with 35 parts of rutile titanium dioxide. Except for the composition of the high-refractive-index filler, the amount of silica-coated flake aluminum powder (8 parts), the amount of waterborne fluorocarbon resin and various additives, the thickness of each layer, the preparation steps, and the construction conditions are all the same as in Example 3, with a dry film thickness of 130 μm. Tests showed a solar reflectance of 0.89 in the 0.3-2.5 μm range, an average infrared emissivity of 0.39 in the 2.5-25 μm range, and an average emissivity of 0.44 in the 8-13 μm atmospheric window range. In the day-night cycle test, the highest temperature on the concrete surface was 42.9 ℃, the lowest temperature was 18.9 ℃, the daily temperature amplitude was 24.0 ℃, and the daily temperature amplitude reduction rate was 52.4%. Compared with Example 3, the solar reflectivity of the single rutile titanium dioxide system decreased, and the highest daytime temperature increased, indicating that without larger particle size fillers such as barium sulfate, it is difficult to form sufficient multi-scale scattering across the entire solar radiation band.

[0094] Comparative Example 7: Barium Sulfate Single Filler System

[0095] This comparative example is the same as Example 3, using the same C40 concrete slab, and sequentially applying an interface sealing primer layer, an aerogel thermal resistance buffer layer, and a high-reflectivity, low-emissivity topcoat. The only difference is that the high-refractive-index filler uses only barium sulfate, without adding rutile titanium dioxide, zinc oxide, and aluminum oxide. The 22 parts of rutile titanium dioxide, 5 parts of zinc oxide, and 8 parts of barium sulfate in the topcoat of Example 3 are replaced with 35 parts of precipitated barium sulfate; that is, the high-refractive-index filler uses only barium sulfate. Except for the composition of the high-refractive-index filler, the amount of silica-coated flake aluminum powder (8 parts), the amount of waterborne fluorocarbon resin and various additives, the thickness of each layer, the preparation steps, and the construction conditions are all the same as in Example 3, with a dry film thickness of 130 μm. Tests showed a solar reflectance of 0.88 in the 0.3-2.5 μm range, an average infrared emissivity of 0.50 in the 2.5-25 μm range, and an average emissivity of 0.61 in the 8-13 μm atmospheric window range. In the day-night cycle test, the highest temperature on the concrete surface was 43.4 ℃, the lowest temperature was 17.6 ℃, the daily temperature amplitude was 25.8 ℃, and the daily temperature amplitude reduction rate was 48.8%. The infrared emissivity of this comparative example was significantly higher than that of the example, indicating that although high-content barium sulfate can provide some solar scattering, it has strong infrared emission characteristics in the atmospheric window band, which is not conducive to the rise of the nighttime temperature trough on the plateau.

[0096] Comparative Example 8: The ratio of high refractive index filler to coated flake aluminum powder is too high.

[0097] This comparative example is basically the same as Example 1, except that the total amount of high refractive index filler is increased to 45 parts, and the amount of coated flake aluminum powder is reduced to 5 parts. The high reflectivity and low emissivity surface layer includes, by mass, 5 parts of silica-coated flake aluminum powder, 20 parts of rutile titanium dioxide, 15 parts of precipitated barium sulfate, 5 parts of zinc oxide, and 5 parts of aluminum oxide.

[0098] The coating is a white reflective heat-insulating paint prepared using only conventional polysiloxane resin. The high-refractive-index filler is barium sulfate only; rutile titanium dioxide, zinc oxide, and aluminum oxide are not added. The composition includes 45 parts polysiloxane resin, 30 parts rutile titanium dioxide, 0.8 parts ammonium polyacrylate dispersant, 2.5 parts propylene glycol methyl ether acetate diluent, 0.3 parts polyether-modified silicone defoamer, and 0.2 parts polyether-modified silicone wetting agent. The dry film thickness is 200 μm. Tests showed a solar reflectance of 0.91 in the 0.3-2.5 μm range, an average infrared emissivity of 0.60 in the 2.5-25 μm range, and an average atmospheric emissivity of 0.68 in the 8-13 μm range. In a day-night cycle test, the highest temperature on the concrete surface was 41.9 ℃, the lowest temperature was 16.4 ℃, the daily temperature amplitude was 25.5 ℃, and the daily temperature amplitude reduction rate was 49.4%. Although this comparative sample has a high solar reflectivity, the aluminum powder content is insufficient due to the high refractive index filler to coated flake aluminum powder mass ratio of 9:1 and the excessive inorganic filler interferes with the directional arrangement of the flake aluminum powder, which significantly increases the infrared emissivity of the coating and reduces its ability to suppress radiative heat dissipation at night.

[0099] The samples from the above embodiments and comparative examples were tested using the following methods:

[0100] 1. The weighted average reflectance of the solar spectrum was measured using an integrating sphere ultraviolet-visible-near-infrared spectrophotometer with a wavelength range of 0.3-2.5 μm, and was calculated based on the AM1.5 solar spectrum.

[0101] 2. The infrared average emissivity was measured using a Fourier transform infrared spectrometer with an integrating sphere accessory to measure the reflectivity in the 2.5-25 μm band. The spectral emissivity of the opaque coating was calculated according to ε(λ)=1-R(λ), and then averaged in the band.

[0102] 3. Thermal conductivity was tested using the transient plane heat source method or the steady-state heat flow meter method, and the sample was a coated board with the same formula.

[0103] 4. The plateau day-night cycle simulation uses 300 mm × 300 mm × 50 mm C40 concrete slabs, with the coating applied to the upper surface; the simulated solar irradiance during the daytime phase is 1000 W / m². 2 The ambient temperature was 35±2 ℃ for 8 hours; during the nighttime phase, the ambient temperature was 10±2 ℃, and a low-temperature radiation plate was used to simulate the long-wave radiation boundary of the cold sky for 16 hours; the specimens were conditioned to stabilize their quality before cycling; the temperature was collected by a thermocouple embedded 2 mm below the surface.

[0104] 5. The daily temperature amplitude reduction rate is calculated by the following formula: η = (ΔT0 - ΔT1) / ΔT0 × 100%, where ΔT0 is the daily temperature amplitude of the uncoated concrete slab surface and ΔT1 is the daily temperature amplitude of the coated concrete slab surface.

[0105] The test results are shown in Table 1.

[0106] Table 1. Test results of the examples and comparative samples.

[0107] Example 1 0.93 0.36 0.036 40.9 19.2 21.7 56.9% Example 2 0.94 0.32 0.032 39.8 20.1 19.7 60.9% Example 3 0.95 0.40 0.039 41.5 18.8 22.7 54.9% Comparative Example 1 0.38 0.91 - 60.8 10.4 50.4 - Comparative Example 2 0.89 0.88 - 43.6 7.9 35.7 29.2% Comparative Example 3 0.76 0.84 0.036 49.2 13.6 35.6 29.4% Comparative Example 4 0.93 0.36 - 44.1 18.5 25.6 49.2% Comparative Example 5 0.94 0.86 - 38.9 6.8 32.1 36.3% Comparative Example 6 0.89 0.44 - 42.9 18.9 24.0 52.4% Comparative Example 7 0.88 0.50 - 43.4 17.6 25.8 48.8% Comparative Example 8 0.91 0.60 - 41.9 16.4 25.5 49.4%

[0108] From the results in Table 1, we can conclude that:

[0109] Although the ordinary white reflective heat insulation coating in Comparative Example 2 and the radiative cooling coating in Comparative Example 5 can reduce the highest daytime temperature, the nighttime temperature trough drops significantly due to their high infrared emissivity, making it difficult to effectively reduce the daily temperature amplitude.

[0110] Comparative Example 3 was coated with only a single aerogel thermal resistance buffer layer, lacking solar reflection and low emissivity regulation, and the daily temperature amplitude was still as high as 35.6, with limited amplitude reduction;

[0111] Comparative Example 4 only has a single high-reflectivity, low-emissivity surface layer coated. Although it has a good amplitude compression effect, it still cannot compare with the embodiment of the present invention. Moreover, it lacks a thermal resistance buffer layer, and the peak temperature during the day is too high.

[0112] Comparative Example 6 has a certain thermal management effect, but it is weaker than that of the Example 6.

[0113] The daily temperature amplitude reduction rates of Comparative Examples 7 and 8 were 48.8% and 49.4%, respectively, slightly lower than 50%, which fully demonstrates the rationality of the composite packing design.

[0114] As can be seen from the data of the embodiments of the present invention, by working together with the interface sealing primer layer, the aerogel thermal resistance buffer layer and the high reflectivity and low emissivity surface layer, the highest and lowest temperatures are both within a more reasonable range, achieving peak shaving and valley raising, which has a more direct engineering significance for reducing the risk of temperature fatigue cracking in high-altitude concrete.

[0115] Finally, it should be noted that the above specific embodiments are only used to describe the purpose, technical solution, and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation of the present invention and is not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the foregoing specific embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions or improvements can be made to some or all of the technical features. These modifications, equivalent substitutions, and improvements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A two-way thermal management coating system for high-altitude concrete, characterized in that, The bidirectional thermal management coating system is applied to the surface of a concrete substrate and consists of, from the inside out, an interface sealing primer layer, an aerogel thermal resistance buffer layer, and a high-reflectivity, low-emissivity surface layer. The interface sealing primer layer comprises, by weight, 40-70 parts of film-forming resin, 0-15 parts of penetrating silane or siloxane, 20-55 parts of water or environmentally friendly diluent, 0.1-1 parts of wetting agent, and 0.1-1 parts of defoamer. The aerogel thermal resistance buffer layer comprises, by weight: 8-25 parts silica aerogel powder, 5-20 parts low thermal conductivity hollow filler, 30-60 parts weather-resistant polymer binder, 0.2-2 parts thickener, 0.2-2 parts dispersant, 0.1-1 parts defoamer, and 10-35 parts water or environmentally friendly diluent. The high-reflectivity, low-emissivity surface layer comprises, by weight: 5-18 parts coated flake aluminum powder, 15-45 parts high-refractive-index filler, 35-65 parts weather-resistant film-forming resin, 0.2-2 parts coupling agent, 0.1-1.5 parts leveling and orientation aid, 0.2-2 parts dispersant, and 10-35 parts diluent or water.

2. The bidirectional thermal management coating system for high-altitude concrete according to claim 1, characterized in that, The film-forming resin in the interface sealing primer layer is one or more of waterborne epoxy resin, silane-modified resin, and organosilicon-modified acrylic resin.

3. The bidirectional thermal management coating system for high-altitude concrete according to claim 1, characterized in that, The dry film thickness of the interface sealing primer layer is 20-80 μm.

4. The bidirectional thermal management coating system for high-altitude concrete according to claim 1, characterized in that, The silica aerogel powder has a particle size D50 of 5-80 μm, a porosity of not less than 85%, and a surface treated with hydrophobic modification; the low thermal conductivity hollow filler is one or more of hollow glass microspheres, ceramic hollow microspheres, and closed-cell expanded perlite micro powder; the weather-resistant polymer binder is one or more of silicone acrylic emulsion, organosilicon resin, waterborne fluorocarbon resin, and aliphatic polyurethane emulsion.

5. A two-way thermal management coating system for high-altitude concrete according to claim 1, characterized in that, The dry film thickness of the aerogel thermal resistance buffer layer is 0.8-3.0 mm.

6. A two-way thermal management coating system for high-altitude concrete according to claim 1, characterized in that, The aspect ratio of the coated flake aluminum powder is 20-100, and the average flake diameter is 5-40 μm; the surface coating layer of the coated flake aluminum powder is one or more of silicon dioxide, aluminum oxide, silane coupling agent coating layer, and acrylic resin coating layer.

7. A two-way thermal management coating system for high-altitude concrete according to claim 1, characterized in that, The high refractive index filler comprises rutile titanium dioxide, barium sulfate, zinc oxide and / or aluminum oxide, wherein the rutile titanium dioxide comprises 8-25 parts by mass and has an average particle size D50 of 0.15-0.50 μm; the barium sulfate comprises 5-20 parts by mass and has an average particle size D50 of 0.3-2.0 μm; and the zinc oxide and / or aluminum oxide comprises 0-5 parts by mass.

8. A two-way thermal management coating system for high-altitude concrete according to claim 1, characterized in that, The weather-resistant film-forming resin in the high-reflectivity, low-emissivity surface layer is one or more of the following: silicone resin, fluorocarbon resin, silicone-acrylic emulsion, and aliphatic polyurethane resin.

9. A two-way thermal management coating system for high-altitude concrete according to claim 1, characterized in that, The dry film thickness of the high-reflectivity, low-emissivity surface layer is 80-250 μm.

10. A method for preparing a bidirectional thermal management coating system for high-altitude concrete as described in any one of claims 1-9, characterized in that, Includes the following steps: S1. Concrete substrate pretreatment: This includes cleaning, grinding, dust removal, and defect repair of the concrete substrate surface. S2. Preparation of interface sealing primer layer: Prepare slurry according to the formula of interface sealing primer layer in claim 1, apply it to the surface of pretreated concrete substrate, and form interface sealing primer layer after curing. S3. Preparation of aerogel thermal resistance buffer layer: Prepare a slurry according to the formulation of aerogel thermal resistance buffer layer in claim 1, apply it to the surface of interface sealing primer layer, and form aerogel thermal resistance buffer layer after curing. S4. Preparation of high-reflectivity, low-emissivity surface layer: Prepare a slurry according to the formula of the high-reflectivity, low-emissivity surface layer in claim 1, apply it to the surface of the aerogel thermal resistance buffer layer, and form a high-reflectivity, low-emissivity surface layer after curing.

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