A multi-layer structure material for reflective cooling pavement and its preparation method

Abstract

This invention relates to a multi-layered reflective cooling pavement structure material and its preparation method, belonging to the technical field of road engineering materials. The multi-layered reflective cooling pavement structure material comprises: a heat-insulating coating, a shielding coating, and a reflective coating layered sequentially. The heat-insulating coating is applied to the pavement. The raw materials for the heat-insulating coating include a coating matrix, a film-forming aid, and SiO2 aerogel. The raw materials for the shielding coating include a coating matrix, a film-forming aid, and cesium tungsten bronze. The raw materials for the reflective coating include a coating matrix, a film-forming aid, and lignin fiber. The multi-layered reflective cooling pavement structure material of this invention exhibits excellent optical properties, cooling performance, and road performance.

Description

Technical Field

[0001] This invention belongs to the field of road engineering materials technology, specifically relating to a multi-layer structure material for reflective cooling pavement and its preparation method. Background Technology

[0002] During the construction of highways and urban roads, asphalt pavement is widely used due to its advantages such as driving comfort, convenient construction and efficient maintenance, accounting for up to 90%. However, asphalt pavement is black in color and has a solar radiation absorption rate of 0.85~0.90. Its surface temperature is easily affected by solar radiation in the environment, which can cause the following hazards: (1) In summer or in high-altitude areas, asphalt pavement absorbs a lot of heat and accumulates in the pavement structure. The surface temperature can easily exceed 65°C, which reduces the load-bearing capacity of asphalt mixture and causes rutting under repeated vehicle loads, increasing road maintenance costs; (2) The natural ground covered by roads in the city gradually loses its climate regulation capacity. Asphalt pavement has a high paving rate and heat capacity, which can easily generate the urban heat island effect (UHI). Excessive urban temperature will increase cooling energy consumption, pollute the air and increase the health risks of urban residents.

[0003] To improve the structural stability of asphalt mixtures in high-temperature environments, the road sector has adopted various strategies, including material modification, structural optimization, improved construction techniques, and quality control. While these methods can significantly enhance the rutting resistance of asphalt mixtures and improve pavement performance under high-temperature conditions, their core function lies in passively adapting to high temperatures by improving the mechanical properties of the material itself, without fundamentally addressing the excessively high radiation absorption and heat storage characteristics of asphalt materials. Against the backdrop of intensifying urban heat island effects and increasingly deteriorating living environments, the limitations of these passive strategies are becoming increasingly apparent, necessitating the exploration of proactive control measures. In recent years, reflective cooling pavements have received widespread attention due to their significant effect on suppressing surface temperature. This technology enhances the pavement's ability to reflect solar radiation and reduces radiation absorption by coating the surface with a cooling material with high solar reflectivity, thereby suppressing the rise in pavement temperature. Unlike traditional methods, reflective pavement coating technology can not only improve the degradation of asphalt performance caused by high temperatures at the source but also promises to improve the pavement's thermal environment, demonstrating good engineering adaptability and development potential.

[0004] Currently, common road surface cooling coatings are generally single-layer structures with limited spatial constraints. The blended functional fillers often suffer from interference such as obstruction, misalignment, and agglomeration due to differences in density, hydrophilicity / hydrophobicity, and structural shape. This prevents them from fully realizing their cooling effect when applied to the road surface, thus hindering the improvement of coating performance. Furthermore, although newly prepared reflective coatings possess excellent optical properties, road surface cooling coatings need to withstand repeated friction from vehicle wheels. This repeated friction causes wear and tear on the coating material, reducing its cooling effect. Severely worn coatings may even lose their cooling function altogether. In addition, the high reflectivity of reflective coatings results in high visible light reflectivity, which can easily cause glare problems when applied to asphalt pavements, endangering traffic safety. These problems seriously hinder the widespread application of road surface cooling coatings. Summary of the Invention

[0005] To address the aforementioned problems in the existing technology, this invention provides a multi-layered reflective cooling pavement structure material and its preparation method. The technical problem to be solved by this invention is achieved through the following technical solution:

[0006] This invention provides a multi-layer structure material for reflective cooling pavement, comprising: a heat-insulating coating, a shielding coating, and a reflective coating stacked sequentially, wherein the heat-insulating coating is used to coat the pavement;

[0007] The raw materials for the heat-insulating coating include a coating substrate, a film-forming aid, and SiO2 aerogel;

[0008] The raw materials for the masking coating include the coating substrate, the film-forming aid, and cesium tungsten bronze;

[0009] The raw materials for the reflective coating include the coating substrate, the film-forming aid, and lignin fiber.

[0010] In one embodiment of the present invention, the coating substrate comprises, by weight, 100 parts of vinyl ester resin, 1-4 parts of curing agent and 0.6-1.4 parts of accelerator; the film-forming aid comprises 0.5 parts of defoamer and 0.5 parts of leveling agent.

[0011] In one embodiment of the present invention, the vinyl ester resin includes a bisphenol A type vinyl ester resin;

[0012] The curing agent includes methyl ethyl ketone peroxide;

[0013] The accelerator includes cobalt isooctanoate;

[0014] The defoamer includes silicone defoamers;

[0015] The leveling agent includes an organosilicon leveling agent.

[0016] In one embodiment of the present invention, the SiO2 aerogel in the heat insulation coating is 1.5 to 6 parts by weight;

[0017] The weight of cesium tungsten bronze in the shielding coating is 4 to 10 parts;

[0018] The lignin fiber in the reflective coating is 3 to 18 parts by weight.

[0019] Another embodiment of the present invention provides a method for preparing a multi-layered structure material for reflective cooling pavement, comprising the steps of:

[0020] A coating substrate, a film-forming aid, and different functional fillers are mixed to obtain coatings with different functions; wherein, the different functional fillers include heat-insulating filler SiO2 aerogel, shielding filler cesium tungsten bronze, or reflective filler lignin fiber, and correspondingly, the coatings with different functions include heat-insulating coatings, shielding coatings, or reflective coatings.

[0021] The heat-insulating coating is applied to the road surface and cured to form a heat-insulating coating.

[0022] The masking coating is applied onto the heat-insulating coating and cured to form a masking coating-heat-insulating coating.

[0023] The reflective coating is applied onto the shielding coating and cured to form a reflective coating-shielding coating-heat insulation coating, resulting in a multi-layer structure material for reflective cooling pavement.

[0024] In one embodiment of the present invention, a coating substrate, a film-forming aid, and different functional fillers are mixed to obtain a coating material with different functions, including:

[0025] 100 parts by weight of vinyl ester resin and 1 to 4 parts by weight of curing agent are mixed and sheared and stirred. During the stirring process, 0.5 parts by weight of defoamer are added to obtain the first mixture.

[0026] The functional filler is added to the first mixture and sheared and stirred to obtain a second mixture; wherein the SiO2 aerogel is 1.5 to 6 parts by weight, the cesium tungsten bronze is 4 to 10 parts by weight, and the reflective coating is 3 to 18 parts by weight.

[0027] Add 0.6 to 1.4 parts by weight of accelerator to the second mixture and shear and stir, and add 0.5 parts by weight of leveling agent during the stirring process to obtain the coating material.

[0028] In one embodiment of the present invention, the heat-insulating coating is applied to the road surface and cured to form a heat-insulating coating, comprising:

[0029] At room temperature, the heat-insulating coating is applied at a rate of 0.2~0.6 kg / m³. 2 The coating is applied to the road surface in the specified amount and cured at room temperature to form the heat insulation coating.

[0030] In one embodiment of the present invention, the masking coating is applied to the heat-insulating coating and cured to form a masking coating-heat-insulating coating, comprising:

[0031] After the heat-insulating coating has cured for at least 20 minutes, the masking coating is applied at room temperature at a rate of 0.2~0.6 kg / m². 2 The coating amount is applied to the heat insulation coating and cured at room temperature to form the shielding coating-heat insulation coating.

[0032] In one embodiment of the present invention, the reflective coating is applied onto the shielding coating and cured to form a reflective coating-shielding coating-heat insulation coating, resulting in a multi-layer structure material for reflective cooling pavement, comprising:

[0033] After the cured shielding-insulating coating has been cured for at least 20 minutes, the reflective coating is applied at room temperature at a rate of 0.2~0.6 kg / m². 2 The coating amount is applied to the masking coating and cured at room temperature to form a reflective coating-masking coating-heat insulation coating, thus obtaining the multi-layer structure material of the reflective cooling pavement.

[0034] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0035] This invention utilizes SiO2 aerogel as a functional filler in a heat-insulating coating. SiO2 aerogel is an amorphous solid material composed of nanoscale elementary particles and possessing a three-dimensional porous network framework. The resulting porous network can significantly block the heat transfer path of the resin matrix. Cesium tungsten bronze is used as a functional filler in a shielding coating. Cesium tungsten bronze achieves a heat-blocking effect through selective absorption, mitigating road glare caused by high reflectivity and enhancing the visual comfort of the multi-layered coating while achieving cooling. Lignin fiber is used as a functional filler in a reflective coating. Lignin fiber is composed of lignin, cellulose, and hemicellulose. Cellulose has high crystallinity and regular molecular arrangement, and its surface has high specular reflection. Hemicellulose has lower crystallinity and uneven distribution, forming a complex multi-layered structure in the whole fiber, which can promote multiple reflections and scattering of light. Therefore, the multi-layered structure material of the reflective cooling pavement of the present invention uses reflective coating, shielding coating and heat insulation coating as basic units. Through the functional allocation between layers, a system design of single-layer structure layer to multi-layer structure layer is realized, matching the optimal combination form of optical performance, maximizing the synergistic cooling effect of the three types of cooling coatings, and ensuring good road performance and mechanical properties of the multi-layer structure coating. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of a multi-layered reflective cooling pavement material provided in an embodiment of the present invention;

[0037] Figure 2 A schematic diagram of a multilayer structure material provided as a comparative example of the present invention;

[0038] Figure 3 A schematic diagram of another multilayer material provided as a comparative example of the present invention;

[0039] Figure 4 A structural schematic diagram of yet another multilayer material provided as a comparative example of the present invention;

[0040] Figure 5 A schematic diagram of another multilayer material provided as a comparative example of the present invention;

[0041] Figure 6 The indoor test cooling value diagram provided in the embodiments of the present invention;

[0042] Figure 7a The surface temperature and temperature difference curve of the specimen during a continuous 4-day outdoor cooling test provided in this embodiment of the invention;

[0043] Figure 7b The curves showing the changes in key environmental parameters during the 4-day continuous outdoor cooling test of the specimen provided in this embodiment of the invention. Detailed Implementation

[0044] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto.

[0045] Please see Figure 1 , Figure 1 This is a schematic diagram of a multi-layer reflective cooling pavement material provided in an embodiment of the present invention. The material includes a heat-insulating coating, a shielding coating, and a reflective coating stacked sequentially, wherein the heat-insulating coating is used to coat the pavement.

[0046] Specifically, the raw materials for heat-insulating coatings include coating substrate, film-forming aids, and SiO2 aerogel; the raw materials for shielding coatings include coating substrate, film-forming aids, and cesium tungsten bronze; and the raw materials for reflective coatings include coating substrate, film-forming aids, and lignin fibers.

[0047] It can be understood that the multi-layer structure material of reflective cooling pavement consists of a heat-insulating coating, a shielding coating, and a reflective coating as basic units. The heat-insulating coating, the shielding coating, and the reflective coating are all formed by mixing the coating matrix, film-forming aids, and functional fillers. The functional filler in the heat-insulating coating is SiO2 aerogel, the functional filler in the shielding coating is cesium tungsten bronze, and the functional filler in the reflective coating is lignin fiber.

[0048] In one specific embodiment, the coating matrix, film-forming aid components, and their weight parts are the same in the heat-insulating coating, masking coating, and reflective coating; the difference lies in the functional filler and its weight parts. By weight, the coating matrix includes 100 parts vinyl ester resin, 1-4 parts curing agent, and 0.6-1.4 parts accelerator; the film-forming aid includes 0.5 parts defoamer and 0.5 parts leveling agent. The heat-insulating coating contains 1.5-6 parts SiO2 aerogel by weight; the masking coating contains 4-10 parts cesium tungsten bronze by weight; and the reflective coating contains 3-18 parts lignin fiber by weight.

[0049] Specifically, the raw materials for the heat-insulating coating include 100 parts vinyl ester resin, 1-4 parts curing agent, 0.6-1.4 parts accelerator, 0.5 parts defoamer, 0.5 parts leveling agent, and 1.5-6 parts SiO2 aerogel. The raw materials for the masking coating include 100 parts vinyl ester resin, 1-4 parts curing agent, 0.6-1.4 parts accelerator, 0.5 parts defoamer, 0.5 parts leveling agent, and 4-10 parts cesium tungsten bronze. The raw materials for the reflective coating include 100 parts vinyl ester resin, 1-4 parts curing agent, 0.6-1.4 parts accelerator, 0.5 parts defoamer, 0.5 parts leveling agent, and 3-18 parts lignin fiber.

[0050] Vinyl ester resins include bisphenol A type vinyl ester resins. Bisphenol A type vinyl ester resins are transparent, slightly yellow liquids with an acid value of 11–19 mg KOH / g, a solid content of 56%–62%, and a viscosity of 0.35–0.58 Pa at 25°C. s, with a density of 1.15 g / ml.

[0051] The curing agent includes methyl ethyl ketone peroxide (MEKP). MEKP is a colorless and transparent liquid with a density of 1.16 g / ml, an active oxygen content of 9-10%, and a molecular weight of 210.22.

[0052] The accelerator includes cobalt isooctanoate. Cobalt isooctanoate is a uniform purple-blue liquid with a density of 1.01 g / ml, a metal content of 8 ± 0.2%, and a molecular weight of 345.34.

[0053] Defoamers include silicone defoamers. For example, a commercially available material, BYK-022, is used as the defoamer.

[0054] Leveling agents include silicone leveling agents. For example, a commercially available common material, BYK-333, is used as the leveling agent.

[0055] SiO2 aerogel is a commercially available material with a density of 0.08 g / cm³. 3 Porosity > 90%, specific surface area 800 m² 2 / g, thermal conductivity at 25℃ is 0.017W / (m K), with a primary particle size of 20 nm.

[0056] The molecular formula of cesium tungsten bronze is Cs 0.30 WO3 has a density of 7.1 g / cm³. 3 Specific surface area is 30~60m² 2 / g, with a particle size of 20~100nm and a band gap energy of 2~3eV.

[0057] Lignin fiber is a commercially available material. It has a white, fibrous appearance and a density of 1.5 ± 0.1 g / cm³. 3 Specific surface area 50m² 2 / g, thermal decomposition temperature is 300℃, and tensile strength is 300±50MPa. Lignin fiber is composed of lignin, cellulose, and hemicellulose.

[0058] This invention also provides a method for preparing a multi-layered reflective cooling pavement material. This method uses lignin fiber, cesium tungsten bronze, and SiO2 gel as functional fillers, vinyl ester resin, accelerator, and curing agent as coating matrix, and defoamer and leveling agent as film-forming aids. The multi-layered material is formed through high-speed shearing. The specific steps include:

[0059] S1. Mix the coating substrate, film-forming aid and different functional fillers to obtain coatings with different functions.

[0060] Specifically, different functional fillers include heat-insulating filler SiO2 aerogel, shielding filler cesium tungsten bronze or reflective filler lignin fiber, and correspondingly, different functional coatings include heat-insulating coatings, shielding coatings or reflective coatings.

[0061] Step S1 specifically includes:

[0062] S11. Mix 100 parts by weight of vinyl ester resin and 1 to 4 parts by weight of curing agent and then shear and stir. For example, the shear and stir rate is 600 r / min and the time is 5 min. Add 0.5 parts by weight of defoamer during the stirring process to obtain the first mixture.

[0063] S12. The functional filler is added to the first mixture and sheared and stirred. For example, the shearing and stirring rate is 800 r / min and the time is 15 min to obtain the second mixture. The weight parts of SiO2 aerogel are 1.5 to 6 parts, the weight parts of cesium tungsten bronze are 4 to 10 parts, and the weight parts of reflective coating are 3 to 18 parts.

[0064] In this embodiment, to ensure the dispersibility of the functional filler in the resin matrix, the functional filler needs to be added to the coating matrix material at a uniform rate within 5 minutes.

[0065] S13. Add 0.6 to 1.4 parts by weight of accelerator to the second mixture and shear stir. For example, the shear stirring rate is 600 r / min and the time is 1 min. Add 0.5 parts by weight of leveling agent during the stirring process. After shear stirring, the coating is obtained.

[0066] S2. Apply the heat insulation coating to the road surface and cure it to form a heat insulation coating.

[0067] Specifically, at room temperature, the heat insulation coating should be applied at a rate of 0.2~0.6 kg / m². 2 The coating is applied to the road surface and cured at room temperature to form a heat-insulating coating.

[0068] S3. Apply the masking coating onto the heat insulation coating and cure it to form a masking coating-heat insulation coating.

[0069] Specifically, after the cured heat-insulating coating has been cured for at least 20 minutes, the masking coating is applied at room temperature at a rate of 0.2~0.6 kg / m². 2 The coating amount is applied to the heat insulation coating and cured at room temperature to form a masking coating-heat insulation coating.

[0070] S4. Apply the reflective coating onto the masking coating and cure it to form a reflective coating-masking coating-heat insulation coating, thus obtaining a multi-layer structure material for reflective cooling pavement.

[0071] Specifically, after the cured masking / heat-insulating coating has been cured for at least 20 minutes, the reflective coating is applied at room temperature at a rate of 0.2~0.6 kg / m². 2 The coating amount is applied to the masking coating and cured at room temperature to form a reflective coating-masking coating-heat insulation coating, resulting in a multi-layer structure material for reflective cooling pavement.

[0072] It should be noted that all operations in the preparation method of this invention are performed at room temperature. Furthermore, this preparation method can be performed by first preparing the heat-insulating coating, the masking coating, and the reflective coating, and then sequentially applying the heat-insulating coating, the masking coating, and the reflective coating; or by proceeding in the order of preparing the heat-insulating coating, applying the heat-insulating coating, preparing the masking coating, applying the masking coating, preparing the reflective coating, and applying the reflective coating.

[0073] In this embodiment of the invention, vinyl ester resin possesses high strength, chemical resistance, and molding and processing properties. Its molecular structure contains vinyl double bonds. During curing, free radicals generated from the decomposition of peroxides can cause the vinyl double bonds to break and generate new free radicals, thereby initiating polymer chain growth and interconnection to form a highly cross-linked three-dimensional network structure. Because the free radical polymerization reaction rate is relatively fast and has no special temperature requirements, vinyl ester resin cures faster than conventional epoxy resins, undergoing curing reactions at room temperature, making it more suitable for the construction environment of road coatings. Under the synergistic effect of accelerators and curing agents, the resulting matrix material exhibits excellent tensile strength, possessing the dual functions of load-bearing filler and road surface bonding.

[0074] In this embodiment of the invention, the heat-insulating filler is SiO2 aerogel. SiO2 aerogel is an amorphous solid material composed of nanoscale basic particles and possessing a three-dimensional porous network framework. The porous network formed can significantly block the heat transfer path of the resin matrix. The primary particles contained in the three-dimensional framework of SiO2 aerogel are spherical particles with a particle size of about 20 nm in the microscopic morphology, forming an overall porous network structure with a high specific surface area. Due to the small particle size, the heat-insulating coating prepared from it can produce a heat-insulating effect with a relatively small coating thickness, and the coating thickness can be effectively controlled when used as a heat-insulating functional filler.

[0075] In this embodiment of the invention, the shielding filler uses cesium tungsten bronze, a nanomaterial with a band gap of approximately 2-3 eV. While transmitting visible light, it intrinsically absorbs and blocks ultraviolet light from solar radiation. Simultaneously, this nanomaterial, due to localized surface plasmon resonance and free carrier absorption mechanisms, can also absorb and block near-infrared light, effectively preventing heat generated by near-infrared light from entering the road structure. Unlike high-reflectivity materials that cool through reflection, cesium tungsten bronze achieves thermal blocking through selective absorption, mitigating road glare caused by high reflectivity and enhancing the visual comfort of the multi-layered coating while simultaneously reducing heat.

[0076] In this embodiment of the invention, the reflective filler is lignin fiber, which is composed of lignin, cellulose, and hemicellulose. Cellulose has high crystallinity and a regular molecular arrangement, resulting in high specular reflectivity. Hemicellulose has lower crystallinity and uneven distribution, forming a complex multi-layered structure within the fiber, which promotes multiple reflections and scattering of light. Furthermore, cellulose is a columnar structure with a relatively large aspect ratio, increasing the contact area between the functional filler and the resin matrix, allowing for mechanical bonding at the interface. Simultaneously, the chemical functional groups on the surface of the functional filler can form covalent bonds, hydrogen bonds, and van der Waals forces with the resin matrix. The larger surface area provides more surface functional groups, resulting in a stronger chemical bond between the lignin fiber and the resin matrix, giving the coating good toughness and strength. Therefore, the reflective coating formed by lignin fiber possesses both excellent reflective properties and high toughness and strength.

[0077] In this embodiment of the invention, the multi-layer structured coating for reflective cooling pavement consists of a reflective coating, a shielding coating, and a heat-insulating coating as basic units. The system design of single-layer to multi-layer structured layers is achieved through the functional allocation between layers, matching the optimal combination form for optical performance, maximizing the synergistic cooling effect of the three types of cooling coatings, and ensuring good road performance and mechanical properties of the multi-layer structured coating.

[0078] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be considered as specific limitations of the invention. Unless otherwise specified, the instruments and equipment involved in the following embodiments are conventional instruments and equipment; the industrial raw materials involved are commercially available conventional industrial raw materials; and the testing methods involved are conventional testing methods.

[0079] Example 1

[0080] This embodiment provides a method for preparing a multi-layer structure material for reflective cooling pavement, including the following steps:

[0081] S1. Mix vinyl ester resin (100 parts by weight) with curing agent (3 parts by weight), and shear and stir at a rate of 600 r / min for 5 min. During the stirring process, slowly and evenly add defoamer (0.5 parts by weight) to obtain the first mixture A.

[0082] S2. Add the functional filler SiO2 aerogel (3 parts by weight) to the first mixture A at a uniform rate, and then shear and stir at a high speed of 800 r / min for 15 min to obtain the second mixture B.

[0083] S3. Add the accelerator (1.0 part by weight) to the second mixture B, and quickly add the leveling agent (0.5 part by weight) during the stirring process. After high-speed shearing and stirring at a rate of 600 r / min for 1 min, the heat insulation coating is obtained.

[0084] S4. Apply the heat insulation coating at room temperature at a rate of 0.2 kg / m². 2 The coating is applied evenly and smoothly to the pretreated asphalt pavement and cured at room temperature to form a heat-insulating coating. The pretreated asphalt pavement has a clean and dry surface.

[0085] S5. Repeat steps S1 to S3 under the same process conditions, except that in step S2 the functional filler is replaced with cesium tungsten bronze, with a weight of 8 parts, to obtain the masking coating.

[0086] S6. After the heat insulation coating formed in step S4 has been cured for at least 20 minutes, apply the masking coating at room temperature at a rate of 0.4 kg / m². 2 The coating is evenly and smoothly applied to the heat insulation coating and cured at room temperature to form a masking coating-heat insulation coating.

[0087] S7. Repeat steps S1 to S3 under the same process conditions, except that in step S2, the functional filler is replaced with lignin fiber, with a weight of 8 parts, to obtain the reflective coating.

[0088] S8. After the masking coating-heat insulation coating formed in step S6 has been cured for at least 20 minutes, apply the reflective coating at room temperature at a rate of 0.4 kg / m². 2 The coating is evenly and smoothly applied onto the masking layer and cured at room temperature to form a multi-layered reflective and cooling pavement structure material with a spatial layering of reflective coating (top layer) - masking coating (intermediate layer) - heat insulation coating (bottom layer). This material is designated as M1, and its structure is as follows: Figure 1 As shown, the top and middle layers are optical layers, and the bottom layer is a heat-resistant layer.

[0089] Comparative Example 1

[0090] The comparative example uses the same process conditions as Example 1, except that the coating order is changed and the spatial arrangement of the single-layer coatings is different. From top to bottom, they are: masking coating (top layer) - reflective coating (intermediate layer) - heat insulation coating (bottom layer). This material is denoted as M2, and its structure is as follows: Figure 2 As shown, Figure 2 This is a schematic diagram of a multilayer material provided as a comparative example of the present invention, wherein the top layer and the middle layer are optical layers, and the bottom layer is a heat-insulating layer.

[0091] Comparative Example 2

[0092] The comparative example uses the same process conditions as Example 1, except that the coating order is changed and the spatial arrangement of the single-layer coatings is different. From top to bottom, they are: reflective coating (top layer) - reflective coating (intermediate layer) - heat-insulating coating (bottom layer). This material is designated M3, and its structure is as follows: Figure 3 As shown, Figure 3 This is a schematic diagram of another multilayer material provided as a comparative example of the present invention, wherein the top layer and the middle layer are optical layers, and the bottom layer is a heat-resistant layer.

[0093] Comparative Example 3

[0094] The comparative example uses the same process conditions as Example 1, except that the coating order is changed and the spatial arrangement of the single-layer coatings is different. From top to bottom, they are: masking coating (top layer) - masking coating (intermediate layer) - heat insulation coating (bottom layer). This material is designated M4, and its structure is as follows: Figure 4 Show, Figure 4 This is a schematic diagram of another multilayer material provided as a comparative example of the present invention, wherein the top layer and the middle layer are optical layers, and the bottom layer is a heat-insulating layer.

[0095] Comparative Example 4

[0096] This comparative example provides a method for preparing a multilayer structure material, including the following steps:

[0097] S1. Prepare the heat-insulating coating using the same process conditions as steps S1 to S4 of Example 1.

[0098] S2. Using the same process conditions as steps S1-S3 in Example 1, except that the functional filler is replaced with lignin fiber and cesium tungsten bronze, and a reflective coating and a masking coating are prepared simultaneously. The two coatings are mixed evenly, and then the heat insulation coating formed in step S1 is cured for at least 20 minutes, followed by curing at 0.4 kg / m³. 2 The coating is evenly applied onto the heat-insulating coating and allowed to fully cure at room temperature, forming a multi-layered structure with a spatial arrangement from top to bottom consisting of a reflective / shielding blend coating (top layer) and a heat-insulating coating (bottom layer). This material is designated M5, and its structure is as follows: Figure 5 Show, Figure 5This is a schematic diagram of another multilayer material provided as a comparative example of the present invention, wherein the top layer is an optical layer and the bottom layer is a heat-insulating layer.

[0099] The materials prepared in Example 1 and Comparative Examples 1-4 were subjected to full-spectrum reflectance testing using ultraviolet, visible, and near-infrared spectrophotometers, coating brightness testing using a colorimeter, and indoor cooling tests were conducted. The test results are shown in Table 1 and [Table data missing]. Figure 6 Table 1 shows the test results for full-spectrum reflectance, brightness, and maximum cooling value. Figure 6 The indoor test cooling value diagram provided in the embodiment of the present invention is as follows. Figure 6 The blue bars represent the maximum temperature drop, and the green bars represent the average temperature drop.

[0100] Table 1

[0101]

[0102] Combination Figures 1-6 As shown in Table 1, the optical layer of the M3 coating consists only of a reflective coating, and its maximum surface temperature drop is 3.7℃ lower than that of the M1 coating. It is speculated that the middle layer of the M3 coating is a reflective coating identical to the surface layer, thus only extending the optical path of the incident light wave, leading to increased internal scattering and hindering the transmission of secondary reflected light waves. In contrast, the middle layer of the M1 coating is a shielding coating that complements the surface layer. This shielding coating absorbs incident light waves that pass through the reflective coating, thus having a better effect on the incident light wave. The optical layer of the M4 coating consists only of a shielding coating, and its maximum surface temperature drop is 2.4℃ lower than that of the M2 coating. Because the middle layer of the M4 coating is a shielding coating identical to the surface layer, the increased cesium tungsten bronze nanoparticles per unit area crowd out the transmission channel of the incident light. Simultaneously, the cesium tungsten bronze in the surface layer saturates due to electronic transition saturation of the optical absorption channel, thus limiting the cooling of the M4 coating. The M2 coating, composed of a reflective coating layer and a top layer, has complementary functions. Light waves transmitted through the top layer are further reflected into the top layer and the external space, thus enhancing the cooling performance of the M2 coating. The results consistently show that the performance of the synergistic optical coating is significantly better than that of a single-function coating. Among the five combinations, the M5 coating, which uses a blend of reflective and shielding coatings to prepare the optical layer, exhibits the lowest cooling values ​​across all categories. This indicates that the blended lignin fibers and cesium tungsten bronze interfere with each other, hindering the full utilization of the optical layer's reflection and shielding functions. The slightly lower cooling performance of the M2 coating compared to the M1 coating is due to the limitations of using a shielding coating in the top layer. When the reflective coating in the intermediate layer reflects the incident light a second time, the cesium tungsten bronze in the top layer blocks part of the reflection path. Simultaneously, the cesium tungsten bronze in the top layer is already in a saturated absorption state and cannot continue to absorb the secondary reflected light waves, resulting in insufficient complementary reflective function of the intermediate layer.

[0103] Therefore, the preferred embodiment 1 has better reflective and cooling properties, and its brightness is lower than the high brightness value that causes glare. It is a multi-layered coating with reasonable spatial arrangement and excellent optical and cooling performance (reflective coating-masking coating-thermal insulation coating, functional filler weight parts: 8 parts lignin fiber, 8 parts cesium tungsten bronze, 3 parts SiO2 aerogel).

[0104] Furthermore, the adhesion, anti-slip, abrasion resistance, water resistance and alkali resistance of the material in Example 1 were tested, and the test results are shown in Table 2.

[0105] Table 2

[0106]

[0107] As shown in Table 2, the material of Example 1 exhibits good bonding strength, wear resistance, anti-skid properties, water resistance, and alkali resistance. Therefore, Example 1 is preferably a multi-layer road surface coating with balanced optical properties, cooling properties, road performance, and mechanical properties, and can be used in complex environments such as asphalt pavements.

[0108] Furthermore, the outdoor cooling performance of the material in Example 1 was tested. The test results can be found in [link to test results]. Figures 7a-7b , Figures 7a-7b This is a graph showing the test results of a specimen subjected to a continuous 4-day outdoor cooling test provided in an embodiment of the present invention. Figure 7a This is a curve showing the surface temperature of the specimen versus the temperature difference. Figure 7b The curves show the changes in the main environmental parameters during the experiment.

[0109] Figure 7a The effective solar radiation periods (daytime) are 09:21-18:24, 07:19-18:51, 07:18-18:48, and 07:20-17:58. It can be found that the temperature curves of the blank specimen and the coated specimen are highly consistent. In the 4-day continuous test, the maximum temperature drop was 11.6℃, which occurred around 14:05 on March 18. The calculated average daytime temperature drop of the coating was 4.65℃. Figure 7b The data for air temperature and solar radiation intensity were collected by a meteorological station during the experiment. The peak solar radiation intensity generally occurred between 12:30 and 13:00, while the peak values ​​for the specimen surface temperature and temperature difference occurred between 13:20 and 14:10, indicating a lag in the temperature change of the specimen, meaning that the transfer of solar radiation heat from the environment to the specimen surface requires conduction time. Additionally, Figure 7aThe negative temperature difference observed typically occurs between 1:00 AM and 5:00 AM, indicating that the coating prevents the specimen from releasing heat during this period. This results in the coated specimen having a higher surface temperature than the blank specimen. This pattern suggests that the cooling coating can prevent the asphalt pavement from transferring heat to the urban environment at night, effectively mitigating the urban heat island effect. In the multilayer structure material prepared in Example 1, the bottom layer is a heat-insulating coating. During the day, it can delay the transfer of solar radiation heat to the asphalt pavement, and at night, it can prevent the release of heat from the road structure to the environment, helping to alleviate fatigue damage to the pavement structure caused by diurnal temperature fluctuations.

[0110] Example 2

[0111] This embodiment provides a method for preparing a resin matrix in a multilayer structure material for reflective cooling pavement and its performance testing. The resin matrix consists of a coating matrix and a film-forming aid. The preparation method includes the following steps:

[0112] S1. Add curing agent (3 parts by weight) to vinyl ester resin (100 parts by weight) and stir evenly at 600 r / min for 5 min at room temperature to obtain solution A.

[0113] S2. Add accelerator (1 part by weight), defoamer (0.5 parts by weight) and leveling agent (0.5 parts by weight) dropwise to solution A. Stir evenly for 1 minute at 600 r / min using a stirrer to obtain solution B, which is the resin-based coating.

[0114] S3, respectively at 0.4 kg / m 2 0.2kg / m 2 The coating material is applied evenly to the resin matrix and cured at room temperature to form a resin matrix coating.

[0115] Furthermore, the coating dosage is 0.4 kg / m². 2 The reflectivity and cooling tests were performed on the coating resin matrix, with a coating amount of 0.2 kg / m². 2 The thermal conductivity of the coated resin matrix was tested.

[0116] Example 3

[0117] This embodiment provides a method for preparing a reflective coating in a multilayer structure material for reflective cooling pavement and its performance testing. The preparation method includes the following steps:

[0118] S1. Prepare reflective coating material.

[0119] S11. Weigh the raw materials: by weight, 100 parts vinyl ester resin, 3 parts curing agent, 1 part accelerator, 0.5 parts leveling agent, 0.5 parts defoamer, and 8 parts lignin fiber (functional filler).

[0120] S12. Mix the vinyl ester resin with the curing agent, and shear and stir at a rate of 600 r / min for 5 min. During the stirring process, slowly and evenly add the defoamer to obtain the first mixture A.

[0121] S13. Add 8 parts of lignin fiber to the first mixture A and shear and stir at a high speed of 800 r / min for 15 min to obtain the second mixture B.

[0122] S14. Add the accelerator to the second mixture B, and quickly add the leveling agent during the stirring process. After high-speed shearing and stirring at a rate of 600 r / min for 1 min, the third mixture C is obtained. The third mixture C is the reflective coating.

[0123] S2. Preparation of the reflective coating. Using a brush, apply the above-mentioned reflective coating material with reflective properties at a rate of 0.4 kg / m². 2 The coating amount is evenly applied to the pre-treated road rut slab.

[0124] S3. Curing. Allow to cure naturally outdoors. Once the coating is fully cured, check the surface smoothness. If it is not smooth, recoat.

[0125] Furthermore, pavement reflectivity and cooling tests were conducted on the reflective coating.

[0126] Example 4

[0127] The reflective coating was prepared using the same steps and process conditions as in Example 3, except that the lignin fiber content in step S11 was 3 parts by weight.

[0128] Example 5

[0129] The reflective coating was prepared using the same steps and process conditions as in Example 3, except that the lignin fiber content in step S11 was 13 parts by weight.

[0130] Example 6

[0131] The reflective coating was prepared using the same steps and process conditions as in Example 3, except that the lignin fiber content in step S11 was 18 parts by weight.

[0132] Example 7

[0133] The masking coating was prepared using the same steps and process conditions as in Example 3, except that in step S11, the functional filler was replaced by 8 parts by weight of cesium tungsten bronze, and the masking coating was subjected to road surface reflectivity test and cooling test.

[0134] Example 8

[0135] The masking coating was prepared using the same steps and process conditions as in Example 7, except that the weight of cesium tungsten bronze in step S11 was 4 parts.

[0136] Example 9

[0137] The masking coating was prepared using the same steps and process conditions as in Example 7, except that the weight of cesium tungsten bronze in step S11 was 6 parts.

[0138] Example 10

[0139] The masking coating was prepared using the same steps and process conditions as in Example 7, except that the weight of cesium tungsten bronze in step S11 was 10 parts.

[0140] Example 11

[0141] The thermal insulation coating was prepared using the same steps and process conditions as in Example 3, except that the functional filler in step S11 was replaced by 3 parts by weight of SiO2 aerogel, and the coating amount in step S2 was 0.2 kg / m². 2 The thermal conductivity and cooling value of the heat insulation coating were tested.

[0142] Example 12

[0143] The heat-insulating coating was prepared using the same steps and process conditions as in Example 11, except that the SiO2 aerogel in step S11 was 1.5 parts by weight.

[0144] Example 13

[0145] The heat-insulating coating was prepared using the same steps and process conditions as in Example 11, except that the SiO2 aerogel in step S11 was 4.5 parts by weight.

[0146] Example 14

[0147] The heat-insulating coating was prepared using the same steps and process conditions as in Example 11, except that the SiO2 aerogel in step S11 was 6 parts by weight.

[0148] The test results of Examples 2-14 are shown in Table 3.

[0149] Table 3

[0150]

[0151] As shown in Table 3, the coating dosage is 0.4 kg / m². 2The cooling value of the resin matrix coating is only 0.7℃, indicating that the cooling capacity of the resin matrix coating is extremely low. The reflective coating, composed of multi-layered structural units, shows significantly higher reflectivity than the pure resin matrix coating after the addition of lignin fibers, and reduces road surface temperature. This indicates that lignin fibers, as a functional filler in the reflective coating, can effectively reduce road surface radiation and achieve the goal of road surface cooling. Furthermore, due to the phenomenon of lignin fibers accumulating to form light-shielding areas after a certain dosage, the reflectivity of the reflective coating does not continuously increase with increasing dosage (Examples 3-6), but the cooling performance gradually improves. With increasing cesium tungsten bronze dosage, the cooling value of the shielding coating gradually increases, while the full-spectrum reflectivity gradually decreases, reaching a maximum of 3.3%, far lower than the 10%-15% full-spectrum reflectivity of asphalt pavement. This proves that the coating cannot actively reflect light waves and can effectively avoid road glare problems. In the heat-insulating coating, the thermal conductivity first decreases and then increases with the increase of SiO2 aerogel content. The incorporation of SiO2 aerogel forms a porous network structure inside the resin matrix, which blocks the heat transfer path of the coating. When the content is too high, the gaps between the aerogels decrease and continuous heat-conducting channels are formed, accelerating heat transfer. Based on the above analysis, Example 1 has the strongest cooling effect.

[0152] In summary, the multi-layered reflective cooling pavement material of this invention, through the synergistic design of three different cooling coatings—reflective, shielding, and heat-insulating—enhances the pavement's surface reflectivity, optical shielding performance, and heat-blocking performance, while maintaining good visual comfort. This reduces the amount of solar radiation absorbed by the asphalt pavement, blocks heat transfer to the pavement structure, and effectively lowers the pavement structure temperature. It provides a long-term solution to the heat storage problem of asphalt pavements, reduces energy consumption, extends pavement life, and improves urban climate. Furthermore, compared to existing reflective coatings, this coating exhibits less paint loss under wheel loads, better road performance, superior durability, and lower maintenance costs. The multi-layered structural material of this invention possesses excellent optical, cooling, and road performance properties.

[0153] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A multi-layered structure material for reflective cooling pavement, characterized in that, include: A heat-insulating coating, a masking coating, and a reflective coating are stacked in sequence, wherein the heat-insulating coating is used to apply to the road surface; The raw materials for the heat-insulating coating include a coating substrate, a film-forming aid, and SiO2 aerogel; The raw materials for the masking coating include the coating substrate, the film-forming aid, and cesium tungsten bronze; The raw materials for the reflective coating include the coating substrate, the film-forming aid, and lignin fiber.

2. The multi-layer structure material for reflective cooling pavement according to claim 1, characterized in that, By weight, the coating substrate comprises 100 parts vinyl ester resin, 1-4 parts curing agent and 0.6-1.4 parts accelerator; the film-forming aid comprises 0.5 parts defoamer and 0.5 parts leveling agent.

3. The multi-layer structure material for reflective cooling pavement according to claim 2, characterized in that, include: The vinyl ester resin includes bisphenol A type vinyl ester resin; The curing agent includes methyl ethyl ketone peroxide; The accelerator includes cobalt isooctanoate; The defoamer includes silicone defoamers; The leveling agent includes an organosilicon leveling agent.

4. The multi-layer structure material for reflective cooling pavement according to claim 2, characterized in that, The heat insulation coating contains 1.5 to 6 parts by weight of SiO2 aerogel. The weight of cesium tungsten bronze in the shielding coating is 4 to 10 parts; The lignin fiber in the reflective coating is 3 to 18 parts by weight.

5. A method for preparing a multi-layered structure material for reflective cooling pavement, characterized in that, Including the following steps: A coating substrate, a film-forming aid, and different functional fillers are mixed to obtain coatings with different functions; wherein, the different functional fillers include heat-insulating filler SiO2 aerogel, shielding filler cesium tungsten bronze, or reflective filler lignin fiber, and correspondingly, the coatings with different functions include heat-insulating coatings, shielding coatings, or reflective coatings. The heat-insulating coating is applied to the road surface and cured to form a heat-insulating coating. The masking coating is applied onto the heat-insulating coating and cured to form a masking coating-heat-insulating coating. The reflective coating is applied onto the shielding coating and cured to form a reflective coating-shielding coating-heat insulation coating, resulting in a multi-layer structure material for reflective cooling pavement.

6. The method for preparing the multi-layer structure material for reflective cooling pavement according to claim 5, characterized in that, Coatings with different functions are obtained by mixing the coating matrix, film-forming aids, and different functional fillers, including: 100 parts by weight of vinyl ester resin and 1 to 4 parts by weight of curing agent are mixed and sheared and stirred. During the stirring process, 0.5 parts by weight of defoamer are added to obtain the first mixture. The functional filler is added to the first mixture and sheared and stirred to obtain a second mixture; wherein the SiO2 aerogel is 1.5 to 6 parts by weight, the cesium tungsten bronze is 4 to 10 parts by weight, and the reflective coating is 3 to 18 parts by weight. Add 0.6 to 1.4 parts by weight of accelerator to the second mixture and shear and stir, and add 0.5 parts by weight of leveling agent during the stirring process to obtain the coating material.

7. The method for preparing the multi-layer structure material for reflective cooling pavement according to claim 5, characterized in that, Applying the heat-insulating coating to the road surface and curing it to form a heat-insulating coating includes: At room temperature, the heat-insulating coating is applied at a rate of 0.2~0.6 kg / m³. 2 The coating is applied to the road surface in the specified amount and cured at room temperature to form the heat insulation coating.

8. The method for preparing the multi-layer structure material for reflective cooling pavement according to claim 5, characterized in that, The masking coating is applied onto the heat-insulating coating and cured to form a masking coating-heat-insulating coating, comprising: After the heat-insulating coating has cured for at least 20 minutes, the masking coating is applied at room temperature at a rate of 0.2~0.6 kg / m². 2 The coating amount is applied to the heat insulation coating and cured at room temperature to form the shielding coating-heat insulation coating.

9. The method for preparing the multi-layer structure material for reflective cooling pavement according to claim 5, characterized in that, The reflective coating is applied onto the shielding coating and cured to form a reflective coating-shielding coating-heat insulation coating, resulting in a multi-layered reflective cooling pavement material, comprising: After the cured shielding-insulating coating has been cured for at least 20 minutes, the reflective coating is applied at room temperature at a rate of 0.2~0.6 kg / m². 2 The coating amount is applied to the masking coating and cured at room temperature to form a reflective coating-masking coating-heat insulation coating, thus obtaining the multi-layer structure material of the reflective cooling pavement.

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