Thermally-induced reversible color-changing composite coating capable of realizing visible-near infrared spectrum collaborative modulation and preparation method of thermally-induced reversible color-changing composite coating

Abstract

The invention discloses a thermally-induced reversible color-changing composite coating capable of realizing visible-near infrared spectrum collaborative modulation and a preparation method of the thermally-induced reversible color-changing composite coating. The composite temperature control coating is of a multi-layer composite structure composed of a solar spectrum high-reflection base layer, a near-infrared absorption layer, a near-infrared modulation layer and a thermochromic layer. Wherein each layer is prepared from a coating which takes rutile titanium dioxide, silicon dioxide aerogel modified cesium tungsten bronze, nano tin antimony oxide modified vanadium oxide and thermally induced reversible color change microcapsules as fillers. The coating ingeniously realizes high reflection of visible light-near infrared spectrum in sunlight under a high temperature condition and high absorption of visible light-near infrared spectrum in sunlight under a low temperature condition through a multi-layer composite structure design, and the overall modulation performance of the coating on the sunlight reflectance ratio is greatly improved. The coating is excellent in performance, is favorable for realizing the adaptability of a temperature control material to a complex temperature environment, and is of great significance to related technical progress and industrial development.

Description

Technical Field

[0002] The present invention belongs to the field of fine polymer materials, and particularly relates to the preparation of a thermally reversible color-changing composite coating capable of realizing visible-near infrared spectrum synergistic modulation and its application in structural temperature control in fields such as transportation, construction, machinery, and chemical engineering. Background Art

[0004] For engineering structures and space structures serving in an exposed environment, the atmospheric heat convection and solar thermal radiation of the external environment will have a greater impact on the structural temperature, resulting in a large day-night temperature difference or seasonal temperature difference, which will have a greater impact on the durability of the structure itself and the temperature comfort of the internal space environment. Therefore, it is essential to use relevant materials and technical means for structural temperature control.

[0005] Solar radiation is one of the main energy sources for heat exchange between the structure and the external environment. Different surface structures and materials have different response performances to the solar spectrum. If more spectral energy is reflected, the temperature rise under sunlight irradiation can be effectively prevented. If more spectral energy is absorbed, the structure will absorb sunlight and quickly heat up. Therefore, it can be seen that the photothermal conversion performance of the structure surface to sunlight is the most important factor affecting the structural temperature. In the solar spectrum, there is spectral energy in multiple bands, and the spectral energy in the visible light band (300 nm - 780 nm) and the near-infrared band (780 nm - 2500 nm) is the highest, having the greatest impact on the solar thermal effect. Therefore, the response performance of the structure surface to the spectra of these two bands is the key performance for structural temperature control. Conventional structural materials have a single response performance to the spectrum and are difficult to fully meet the complex temperature control requirements of the structure under different environmental conditions. For example, using temperature control materials with a high reflectivity can reduce the temperature rise of the structure under solar radiation in a high-temperature environment and reduce the energy consumption for structural cooling, but it may have a side effect on the structural temperature control load in a cold winter. Therefore, developing intelligent temperature control materials that can have different surface photothermal properties according to different environmental scenarios has important economic and social significance and also brings new development opportunities for the future application research of surface temperature control materials.

[0006] At present, relevant researchers have studied various intelligent surface temperature control materials that regulate surface photothermal properties through different methods. Among them, intelligent temperature control materials regulated by temperature have received a large amount of research attention due to their most direct design ideas and application methods. In Patent CN118638296B, an intelligent temperature control TPU material applied to automotive glass films is disclosed. Through in-situ synthesis technology, thermosensitive temperature control fillers are incorporated into the TPU molecular chain segments, which not only maintains its high light transmittance but also significantly improves its solar energy regulation efficiency. In Patent CN113419580B, an intelligent temperature control device based on passive radiative cooling and solar heating is disclosed. An intelligent temperature control device is prepared by sequentially arranging a passive radiative cooling layer, a thermochromic layer, and a solar heating layer from the outside to the inside, which can achieve passive temperature control with changes in environmental temperature and is applicable to a wide range of ambient air temperature changes. In Patent CN116285442B, a negative-carbon and self-regulating temperature thermochromic coating is disclosed. By modifying reversible color-changing microcapsules with titanium sol, its ultraviolet aging resistance is improved and its bonding force with other inorganic carbonized cementitious materials is enhanced, and the coating performance is excellent.

[0007] From the above description, it can be seen that the currently studied thermally regulated intelligent temperature control materials already have intelligent regulation characteristics and certain practical value. However, in terms of the overall development of technology, they still face some problems. Currently, thermally regulated intelligent temperature control materials mainly include thermochromic coating materials and thermochromic temperature control glass materials, etc. Among them, thermochromic coating materials that change color at room temperature usually use organic thermochromic materials, which have strong regulation performance for the absorption rate in the visible light band. However, due to molecular structure reasons, they usually have no regulation effect on the near-infrared band. Therefore, the total solar light modulation rate usually can only reach 30% at most and it is difficult to further improve. For thermochromic temperature control glass, although it can use the phase change of vanadium oxide materials to achieve regulation in the near-infrared band, in order to ensure the light transmittance, it usually has no regulation performance for visible light, and the regulation rate for sunlight is also within 20%. Moreover, its regulation is mainly for the transmittance, which is different from the reflectance and absorption rate regulation of the coating. Therefore, it can be seen that based on relevant research, further developing new thermally intelligent temperature control materials and improving the overall regulation performance of the materials in the solar spectrum are of great significance for promoting the further development of related technologies and the progress of the industry. Summary of the Invention

[0009] The purpose of the present invention is to solve the above problems and provide a thermally reversible color-changing composite coating capable of realizing synergistic modulation of visible-near infrared spectra and its preparation method.

[0010] A thermally reversible color-changing composite coating capable of realizing visible-near infrared spectrum collaborative modulation according to the present invention is a multi-layer composite structure temperature control coating composed of a solar spectrum high reflection layer, a near infrared absorption layer, a near infrared modulation layer, and a thermochromic layer; wherein the high performance solar light reflection base layer is prepared from a high performance solar light reflection coating added with rutile titanium dioxide; wherein the near infrared absorption layer is prepared from a high near infrared absorption coating added with silica aerogel modified cesium tungsten bronze; wherein the near infrared modulation layer is prepared from a near infrared modulation coating added with nano antimony tin oxide modified vanadium dioxide; wherein the thermochromic layer is prepared from a thermally reversible color-changing coating added with thermally reversible color-changing microcapsules; the dry film thicknesses of the solar spectrum high reflection layer, the near infrared absorption layer, the near infrared modulation layer, and the thermochromic layer are 40 μm to 60 μm, 15 μm to 25 μm, 10 μm to 20 μm, and 30 μm to 50 μm respectively in sequence.

[0011] The high performance solar light reflection coating is composed of a main agent A1 and a curing agent B1; wherein the main agent A1 is prepared from a matrix resin, rutile titanium dioxide filler, solvent, and functional additives; the mass contents of the matrix resin, rutile titanium dioxide filler, solvent, and functional additives are 55% to 72%, 22% to 33%, 3% to 10%, and 1% to 4% respectively based on the total mass of the main agent A1; the curing agent B1 is prepared from a curing agent and a solvent, and the mass contents of the curing agent and the solvent are 85% to 100% and 0 to 15% respectively; the mass ratio of the main agent A1 to the curing agent B1 is 1:(0.08 to 0.22).

[0012] The high near infrared absorption coating is composed of a main agent A2 and a curing agent B2; wherein the main agent A2 is prepared from a matrix resin, silica aerogel modified cesium tungsten bronze filler, solvent, and functional additives; the mass contents of the matrix resin, silica aerogel modified cesium tungsten bronze filler, solvent, and functional additives are 70% to 80%, 15% to 20%, 3% to 5%, and 1% to 3% respectively based on the total mass of the main agent A2; the curing agent B2 is prepared from a curing agent and a solvent, and the mass contents of the curing agent and the solvent are 85% to 100% and 0 to 15% respectively; the mass ratio of the main agent A2 to the curing agent B2 is 1:(0.12 to 0.25).

[0013] The preparation method of silica aerogel modified cesium tungsten bronze in a high near-infrared absorption coating is as follows: (1) Mix tungsten chloride with absolute ethanol and dissolve it completely, then add cesium hydroxide and stir for 5 min, and then add acetic acid and stir evenly; (2) Transfer the reaction precursor solution into a reactor, heat and react at 220°C to 240°C for 24 h, centrifuge, wash and vacuum dry the precipitate to obtain cesium tungsten bronze powder; (3) Then mix the cesium tungsten bronze powder and a certain amount of silica aerogel evenly in N,N-dimethylformamide and ball mill at a speed of 600 rpm for 30 min to obtain silica aerogel modified cesium tungsten bronze; the mass ratio of cesium tungsten bronze to silica aerogel is 1:(0.3 - 0.6).

[0014] The near-infrared modulation coating is composed of A3 main agent and B3 curing agent; the A3 main agent is prepared from matrix resin, nano-tin antimony oxide modified vanadium dioxide filler, solvent and functional additives; the mass contents of the matrix resin, nano-tin antimony oxide modified vanadium dioxide filler, solvent and functional additives are 75% - 85%, 10% - 15%, 3% - 5%, 1% - 3% respectively, based on the total mass of the A3 main agent; the B3 curing agent is prepared from curing agent and solvent, and the mass contents of the curing agent and solvent are 85% - 100% and 0 - 15% respectively; the mass ratio of the A3 main agent to the B3 curing agent is 1:(0.14 - 0.25).

[0015] The preparation method of nano-tin antimony oxide modified vanadium dioxide in the near-infrared modulation coating is as follows: (1) Dissolve vanadium pentoxide and oxalic acid dihydrate in deionized water in a molar ratio of 1:2, and after complete dissolution, add magnesium sulfate and stir for 30 min to obtain a reaction precursor solution; (2) Transfer the reaction precursor solution to a hydrothermal reactor, react at 240°C for 10 h, then ultrasonically clean three times with deionized water and absolute ethanol respectively, vacuum filter and dry at 60°C for 12 h, and grind to obtain magnesium-doped vanadium dioxide powder; (3) Then mix the vanadium dioxide powder and nano-tin antimony oxide evenly in water and ball mill at a speed of 400 rpm - 600 rpm for 30 min; (4) Under a nitrogen atmosphere, heat-treat the ball-milled powder at a temperature of 520°C - 600°C for 3 h to obtain nano-tin antimony oxide modified vanadium dioxide; the doping amount of magnesium element is 1.5% - 2.3% based on the mass of vanadium oxide; the mass ratio of vanadium dioxide to nano-tin antimony oxide is 1:(0.8 - 1.4).

[0016] The heat-induced reversible discoloration coating consists of A4 main agent and B4 curing agent; the A4 main agent is prepared from matrix resin, heat-induced reversible discoloration microcapsule filler, solvent and functional additives; the mass contents of the matrix resin, heat-induced reversible discoloration microcapsule filler, solvent and functional additives are 55% - 72%, 20% - 35%, 3% - 10%, 1% - 4% respectively, based on the total mass of the A4 main agent; the B4 curing agent is prepared from curing agent and solvent, and the mass contents of the curing agent and solvent are 85% - 100% and 0 - 15% respectively; the mass ratio of the A4 main agent to the B4 curing agent is 1:(0.09 - 0.22).

[0017] The preparation method of the heat-induced reversible discoloration microcapsules in the heat-induced reversible discoloration coating comprises the following steps: (1) Dissolve the ternary heat-induced reversible discoloration core material composed of pigment, developer and solvent, add it to the water containing emulsifier, and perform high-speed emulsification under the heating condition of 65°C to obtain the heat-induced reversible discoloration emulsion; (2) Under the condition of heating and stirring, drop the resin prepolymer into the reversible discoloration emulsion at a constant speed. After the dropping is completed, carry out in-situ polymerization at 85°C for 1 h. After filtering and drying the reaction suspension, the heat-induced reversible discoloration microcapsules can be obtained; wherein the pigment is at least one of crystal violet lactone, 2-phenylamino-3-methyl-6-dibutylamino fluorane, 3',6'-dimethoxy fluorane; the developer is at least one of bisphenol A, bisphenol F, bisphenol S; the solvent is at least one of tetradecyl alcohol, glyceryl tridecanoate, methyl stearate, ethyl stearate; the mass concentration of the pigment molecules is 0.8% - 6%, based on the total mass of the discoloration core material, and the mass ratio of the pigment to the developer is 1:(1.5 - 4); the emulsifier is at least one of sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, sodium salt of styrene maleic anhydride copolymer, and the mass concentration is 0.5 - 1%; the resin prepolymer is at least one of melamine resin prepolymer, urea formaldehyde resin prepolymer, methylated melamine formaldehyde resin prepolymer, and the dosage is 5% - 13% of the total mass of the capsules.

[0018] The preparation methods of the high-performance solar reflective coating, high near-infrared absorption coating, near-infrared modulation coating and heat-induced reversible discoloration coating are as follows: Weigh appropriate masses of each component. Disperse and mix the matrix resin and filler using a high-speed disperser under the conditions of 40 - 60°C and a linear velocity of 6 - 10 m / s for 15 min, and then perform ultrasonic treatment for 4 - 10 min. Then add the remaining components to the mixture and disperse for 30 min until the system is homogeneous and stable to obtain the main component of the coating; Disperse and mix the isocyanate and solvent using a high-speed disperser for 15 min until the system is homogeneous and stable to obtain the curing agent component.

[0019] Among them, the matrix resin is at least one of silicone resin, fluorocarbon resin, and polyurethane resin; the solvent is at least one of xylene, acetone, ethanol, isopropanol, butyl acetate, and propylene glycol monomethyl ether acetate; the functional additive is at least one of dispersant, defoamer, leveling agent, adhesion promoter, and thixotropic agent; the isocyanate is at least one of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, cyclohexane dimethylene diisocyanate, benzene dimethylene diisocyanate, polymethylene polyphenyl polyisocyanate, hexamethylene diisocyanate trimer, and hexamethylene diisocyanate biuret; the solvent is at least one of xylene, acetone, ethanol, isopropanol, butyl acetate, and propylene glycol monomethyl ether acetate.

[0020] The preparation method of the thermally reversible color-changing composite coating is that high-performance solar light-reflecting coating, high near-infrared absorption coating, near-infrared modulation coating, and thermally reversible color-changing coating are sequentially formed into coatings with appropriate thicknesses on the substrate; the forming method can be any one of screen printing, spraying, casting and scraping, and roll coating; after each coating is formed, it needs to be dried at room temperature for 24 h and then cured at 60 °C for 12 h before the next coating is formed.

[0021] The positive effect of a thermally reversible color-changing composite coating capable of realizing visible-near-infrared spectrum synergistic modulation in the present invention is that in the present invention, through the ingenious design of the multi-layer composite coating structure, high reflection of the visible-near-infrared spectrum of sunlight under high temperature conditions and high absorption of the visible-near-infrared spectrum of sunlight under low temperature conditions are achieved, thereby realizing a visible-near-infrared spectrum synergistic modulation material system applicable to the structural facade coating system. Among them, the regulation of visible spectrum energy is mainly achieved by means of the thermally reversible color-changing coating system, while the regulation of near-infrared spectrum energy mainly relies on the near-infrared regulation layer containing vanadium oxide. In view of the problem that the vanadium oxide layer cannot achieve near-infrared spectrum absorption at low temperature, a near-infrared absorption layer containing cesium tungsten bronze is introduced to facilitate the absorption of near-infrared spectrum energy passing through the vanadium oxide layer under low temperature conditions.

[0022] In addition, to further improve the coating performance, first, the phase transition point of vanadium oxide is regulated by introducing magnesium element doping, so that the regulation temperature is reduced from the original 68 °C to about 40 °C, achieving an appropriate transition temperature regulation. Secondly, aiming at the problem that the original vanadium oxide has a high absorption in the visible light band, nano-tin antimony oxide is introduced to modify vanadium oxide. Through the construction of a nano-composite structure and high-temperature thermal annealing conditions, a high tin concentration is obtained at the interface and diffused into vanadium oxide, broadening the energy band width of vanadium oxide and avoiding unnecessary defects, thereby effectively improving the visible light transmittance of the film layer and further enhancing its near-infrared modulation performance. In order to reduce the absorption of cesium tungsten bronze in the visible light band while enhancing its near-infrared absorption and temperature control effect, silica aerogel is used to modify cesium tungsten bronze. By ball milling, the cesium tungsten bronze component with a high surface energy will adsorb light silica aerogel particles. Due to the anti-reflection effect of silica, the visible light transmittance of the composite particles is higher than that of pure cesium tungsten bronze. In addition, silica aerogel particles with a diameter of 10 nm or even smaller undergo Rayleigh scattering, which can effectively reduce the scattering perpendicular to the incident light direction, so that the incident near-infrared light is fully absorbed by cesium tungsten bronze. Combined with the strong heat preservation effect of aerogel particles, its heat absorption capacity at low temperature is effectively enhanced.

[0023] As can be seen from the above, through ingenious design and material modification, the present invention prepares a composite coating structure system that can realize the coordinated regulation of visible light and near-infrared light of sunlight due to temperature self-sensing in a suitable environment, and can effectively achieve the effects of heat absorption and heat preservation at low temperature and reflection and cooling at high temperature. This invention patent is of great significance for the preparation and research and development of surface passive temperature control materials with intelligent temperature control functions and their promotion in related application fields. Detailed implementation mode

[0025] The following further describes the present invention in detail with specific examples.

[0026] Example 1: A thermally reversible color-changing composite coating I capable of realizing visible-near-infrared spectrum coordinated modulation, and its preparation process is as follows:

[0027] (1) Weigh 65 parts of fluorocarbon resin, 5 parts of xylene, 28.3 parts of rutile titanium dioxide, 0.5 part of dispersant, 0.5 part of leveling agent and 0.6 part of defoaming agent. Disperse and mix the fluorocarbon resin and rutile titanium dioxide with a high-speed disperser at a linear velocity of 50 °C and 8 m / s for 15 min, then perform ultrasonic treatment for 8 min, and then add the remaining components to the mixture and disperse for 30 min until the system is uniform and stable to obtain the main component AIa of the high-performance sunlight reflection coating.

[0028] (2) Weigh 80 parts of fluorocarbon resin, 3 parts of xylene, 15.3 parts of silica aerogel modified cesium tungsten bronze, 0.5 part of dispersant, 0.5 part of leveling agent, and 0.6 part of defoamer, and prepare the high near-infrared absorption coating AIb by a similar method as in (1).

[0029] (3) Weigh 79 parts of fluorocarbon resin, 7 parts of xylene, 12.4 parts of nano-tin antimony oxide modified vanadium oxide, 0.5 part of dispersant, 0.5 part of leveling agent, and 0.6 part of defoamer, and prepare the near-infrared modulation coating AIc by a similar method as in (1).

[0030] (4) Weigh 70 parts of fluorocarbon resin, 5.4 parts of xylene, 23 parts of thermochromic microcapsules, 0.5 part of dispersant, 0.5 part of leveling agent, and 0.6 part of defoamer, and prepare the thermally reversible color-changing coating AId by a similar method as in (1).

[0031] (5) Disperse and mix 30 parts of toluene diisocyanate, 65 parts of toluene diisocyanate trimer, and 5 parts of xylene using a high-speed disperser for 15 min until the system is homogeneous and stable, then the curing agent component BI of the above coatings can be obtained.

[0032] (6) Weigh the main agent AIa and the curing agent BI according to a mass ratio of 1:0.12, mix them evenly using mechanical stirring, and then prepare a solar spectral high-reflection base layer with a dry film thickness of 60 μm by spraying construction.

[0033] (7) Weigh the main agent AIb and the curing agent BI according to a mass ratio of 1:0.15, mix them evenly using mechanical stirring, and then prepare a near-infrared absorption layer with a dry film thickness of 25 μm by spraying construction after the solar spectral high-reflection base layer is dried and cured.

[0034] (8) Weigh the main agent AIc and the curing agent BI according to a mass ratio of 1:0.15, mix them evenly using mechanical stirring, and then prepare a near-infrared modulation layer with a dry film thickness of 15 μm by spraying construction after the near-infrared absorption layer is dried and cured.

[0035] (9) Weigh the main agent AId and the curing agent BI according to a mass ratio of 1:0.13, mix them evenly using mechanical stirring, and then prepare a thermochromic layer with a dry film thickness of 40 μm by spraying construction after the near-infrared modulation layer is dried and cured, thus obtaining the visible-near-infrared spectrum synergistic modulation thermally reversible color-changing coating I with a composite structure.

[0036] Example 2: A thermally reversible color-changing composite coating II capable of realizing visible-near-infrared spectrum synergistic modulation, and its preparation process is as follows:

[0037] (1) Weigh 65 parts of silicone resin, 6 parts of acetone, 28 parts of rutile titanium dioxide, 0.5 part of dispersant, 0.3 part of defoamer and 0.2 part of thixotropic agent. Use a high-speed disperser to disperse and mix the silicone resin and rutile titanium dioxide at 50 °C and a linear velocity of 8 m / s for 15 min, and then perform ultrasonic treatment for 8 min. Then add the remaining components to the mixture and disperse for 30 min until the system is homogeneous and stable to obtain the main component AIIa of the high-performance solar light-reflecting coating.

[0038] (2) Weigh 80 parts of silicone resin, 3 parts of acetone, 16 parts of silica aerogel-modified cesium tungsten bronze, 0.5 part of dispersant, 0.3 part of defoamer and 0.2 part of thixotropic agent. Prepare the high near-infrared absorption coating AIIb by a similar method as in (1).

[0039] (3) Weigh 79.5 parts of silicone resin, 5.5 parts of acetone, 14 parts of nano-tin antimony oxide-modified vanadium oxide, 0.5 part of dispersant, 0.3 part of defoamer and 0.2 part of thixotropic agent. Prepare the near-infrared modulation coating AIIc by a similar method as in (1).

[0040] (4) Weigh 70 parts of silicone resin, 3 parts of acetone, 26 parts of thermochromic microcapsules, 0.5 part of dispersant, 0.3 part of defoamer and 0.2 part of thixotropic agent. Prepare the thermally reversible color-changing coating AIId by a similar method as in (1).

[0041] (5) Use polymethylene polyphenyl polyisocyanate as the curing agent component BII of the above coatings.

[0042] (6) Weigh the main component AIIa and the curing agent BII according to a mass ratio of 1:0.11. After mixing evenly by mechanical stirring, prepare a solar spectrum high-reflecting base layer with a dry film thickness of 40 μm by spraying construction.

[0043] (7) Weigh the main component AIIb and the curing agent BII according to a mass ratio of 1:0.14. After mixing evenly by mechanical stirring, prepare a near-infrared absorption layer with a dry film thickness of 25 μm by spraying construction after the solar spectrum high-reflecting base layer is dried and cured.

[0044] (8) Weigh the main component AIIc and the curing agent BII according to a mass ratio of 1:0.14. After mixing evenly by mechanical stirring, prepare a near-infrared modulation layer with a dry film thickness of 20 μm by spraying construction after the near-infrared absorption layer is dried and cured.

[0045] (9) Weigh the AIId main agent and the BII curing agent according to a mass ratio of 1:0.12. After mixing them evenly by mechanical stirring, cure them by drying in the near-infrared modulation layer, and then prepare a thermochromic layer with a dry film thickness of 40 μm by spraying construction, thus obtaining the visible-near-infrared spectrum synergistic modulation thermoreversible discoloration coating II with a composite structure.

[0046] Example 3: A thermoreversible discoloration composite coating III capable of realizing visible-near-infrared spectrum synergistic modulation, and its preparation process is as follows:

[0047] (1) Weigh 67 parts of fluorocarbon resin, 5.5 parts of butyl acetate, 24.5 parts of rutile titanium dioxide, 1 part of dispersant, 1 part of defoamer and 1 part of leveling agent. Disperse and mix the fluorocarbon resin and rutile titanium dioxide with a high-speed disperser at 50 °C and a linear velocity of 8 m / s for 15 min, then perform ultrasonic treatment for 8 min, and then add the remaining components to the mixture and disperse for 30 min until the system is uniform and stable to obtain the main agent component AIIIa of the high-performance solar light reflecting coating.

[0048] (2) Weigh 74 parts of fluorocarbon resin, 8 parts of butyl acetate, 15 parts of cesium tungsten bronze modified by silica aerogel, 1 part of dispersant, 1 part of defoamer and 1 part of leveling agent, and prepare the high near-infrared absorption coating AIIIb by a similar method to (1).

[0049] (3) Weigh 75 parts of fluorocarbon resin, 7 parts of butyl acetate, 15 parts of vanadium oxide modified by antimony tin oxide nanometer, 1 part of dispersant, 1 part of defoamer and 1 part of leveling agent, and prepare the near-infrared modulation coating AIIIc by a similar method to (1).

[0050] (4) Weigh 62 parts of fluorocarbon resin, 4 parts of butyl acetate, 31 parts of thermochromic microcapsules, 1 part of dispersant, 1 part of defoamer and 1 part of leveling agent, and prepare the thermoreversible discoloration coating AIIId by a similar method to (1).

[0051] (5) Disperse and mix 85 parts of isophorone diisocyanate and 15 parts of butyl acetate with a high-speed disperser for 15 min until the system is uniform and stable, then the curing agent component BIII of the above coatings can be obtained.

[0052] (6) Weigh the AIIIa main agent and the BIII curing agent according to a mass ratio of 1:0.12. After mixing them evenly by mechanical stirring, prepare a high solar spectrum reflection base layer with a dry film thickness of 45 μm by spraying construction.

[0053] (7) Weigh the AIIIb main agent and the BIII curing agent according to a mass ratio of 1:0.14. After mixing them evenly by mechanical stirring, prepare a near-infrared absorption layer with a dry film thickness of 20 μm by spraying construction after the high solar spectrum reflection base layer is dried and cured.

[0054] (8) Weigh the main agent AIIIc and the curing agent BIII according to the mass ratio of 1:0.14. After mixing them evenly by mechanical stirring, dry and cure them in the near-infrared absorption layer, and then prepare a near-infrared modulation layer with a dry film thickness of 15 μm by spraying construction.

[0055] (9) Weigh the main agent AIIId and the curing agent BIII according to the mass ratio of 1:0.11. After mixing them evenly by mechanical stirring, dry and cure them in the near-infrared modulation layer, and then prepare a thermochromic layer with a dry film thickness of 35 μm by spraying construction, thus obtaining the visible-near-infrared spectrum synergistic modulation thermoreversible color-changing coating III with a composite structure.

[0056] Example 4: A thermoreversible color-changing composite coating IV capable of realizing visible-near-infrared spectrum synergistic modulation, and its preparation process is as follows:

[0057] (1) Weigh 66 parts of polyurethane resin, 3.8 parts of ethanol, 29 parts of rutile titanium dioxide, 0.6 part of dispersant and 0.6 part of leveling agent. Disperse and mix the polyurethane resin and rutile titanium dioxide with a high-speed disperser at 50 °C and a linear velocity of 8 m / s for 15 min, then perform ultrasonic treatment for 8 min, and then add the remaining components to the mixture and disperse for 30 min until the system is uniform and stable to obtain the main agent component AIVa of the high-performance sunlight-reflecting coating.

[0058] (2) Weigh 72.5 parts of polyurethane resin, 6.8 parts of ethanol, 19.5 parts of silica aerogel-modified cesium tungsten bronze, 0.6 part of dispersant and 0.6 part of leveling agent, and prepare the high near-infrared absorption coating AIVb by a similar method to (1).

[0059] (3) Weigh 84 parts of polyurethane resin, 3.8 parts of ethanol, 11 parts of nano-antimony-doped tin oxide-modified vanadium oxide, 0.6 part of dispersant and 0.6 part of leveling agent, and prepare the near-infrared modulation coating AIVc by a similar method to (1).

[0060] (4) Weigh 60 parts of polyurethane resin, 6.8 parts of ethanol, 32 parts of thermochromic microcapsules, 0.6 part of dispersant and 0.6 part of leveling agent, and prepare the thermoreversible color-changing coating AIVd by a similar method to (1).

[0061] (5) Use dicyclohexylmethane diisocyanate as the curing agent component BIV for the above coatings.

[0062] (6) Weigh the main agent AIVa and the curing agent BIV according to the mass ratio of 1:0.11. After mixing them evenly by mechanical stirring, prepare a high sunlight-spectrum reflection base layer with a dry film thickness of 45 μm by spraying construction.

[0063] (7) Weigh the main agent AIVb and the curing agent BIV according to a mass ratio of 1:0.12. After mixing them evenly by mechanical stirring, spray them on the dried and cured high-reflection base layer of the solar spectrum to prepare a near-infrared absorption layer with a dry film thickness of 18 μm.

[0064] (8) Weigh the main agent AIVc and the curing agent BIV according to a mass ratio of 1:0.14. After mixing them evenly by mechanical stirring, spray them on the dried and cured near-infrared absorption layer to prepare a near-infrared modulation layer with a dry film thickness of 15 μm.

[0065] (9) Weigh the main agent AIVd and the curing agent BIV according to a mass ratio of 1:0.09. After mixing them evenly by mechanical stirring, spray them on the dried and cured near-infrared modulation layer to prepare a thermochromic layer with a dry film thickness of 40 μm, and then a visible-near-infrared spectrum synergistic modulation thermoreversible color-changing coating IV with a composite structure can be obtained.

[0066] Example 5: A thermoreversible color-changing composite coating V capable of visible-near-infrared spectrum synergistic modulation, and its preparation process is as follows:

[0067] (1) Weigh 60 parts of silicone resin, 8.8 parts of butyl acetate, 30 parts of rutile titanium dioxide, 0.6 part of defoamer and 0.6 part of thixotropic agent. Disperse and mix the silicone resin and rutile titanium dioxide with a high-speed disperser at a linear velocity of 8 m / s at 50 °C for 15 min, then perform ultrasonic treatment for 8 min, and then add the remaining components to the mixture and disperse for 30 min until the system is homogeneous and stable to obtain the main agent component AVa of the high-performance solar light reflection coating.

[0068] (2) Weigh 77 parts of silicone resin, 5.8 parts of butyl acetate, 16 parts of silica aerogel modified cesium tungsten bronze, 0.6 part of defoamer and 0.6 part of thixotropic agent, and prepare the high near-infrared absorption coating AVb by a similar method to (1).

[0069] (3) Weigh 80 parts of silicone resin, 6.3 parts of butyl acetate, 12.5 parts of nano-antimony tin oxide modified vanadium oxide, 0.6 part of defoamer and 0.6 part of thixotropic agent, and prepare the near-infrared modulation coating AVc by a similar method to (1).

[0070] (4) Weigh 70 parts of silicone resin, 5.8 parts of butyl acetate, 23 parts of thermochromic microcapsules, 0.6 part of defoamer and 0.6 part of thixotropic agent, and prepare the thermoreversible color-changing coating AVd by a similar method to (1).

[0071] (5) Disperse and mix 35 parts of dicyclohexylmethane diisocyanate, 60 parts of hexamethylene diisocyanate biuret and 5 parts of butyl acetate with a high-speed disperser for 15 min until the system is homogeneous and stable, and then the curing agent component BV of the above coatings can be obtained.

[0072] (6) Weigh the main agent AVa and the curing agent BV according to a mass ratio of 1:0.09. After mixing them evenly by mechanical stirring, prepare a high solar spectrum reflective base layer with a dry film thickness of 50 μm through spraying construction.

[0073] (7) Weigh the main agent AVb and the curing agent BV according to a mass ratio of 1:0.12. After mixing them evenly by mechanical stirring, prepare a near-infrared absorption layer with a dry film thickness of 20 μm through spraying construction after the high solar spectrum reflective base layer is dried and cured.

[0074] (8) Weigh the main agent AVc and the curing agent BV according to a mass ratio of 1:0.12. After mixing them evenly by mechanical stirring, prepare a near-infrared modulation layer with a dry film thickness of 15 μm through spraying construction after the near-infrared absorption layer is dried and cured.

[0075] (9) Weigh the main agent AVd and the curing agent BV according to a mass ratio of 1:0.11. After mixing them evenly by mechanical stirring, prepare a thermochromic layer with a dry film thickness of 50 μm through spraying construction after the near-infrared modulation layer is dried and cured, and then a visible-near-infrared spectrum synergistic modulation thermoreversible color-changing coating V with a composite structure can be obtained.

[0076] Example 6: A thermoreversible color-changing composite coating VI capable of realizing visible-near-infrared spectrum synergistic modulation, and its preparation process is as follows:

[0077] (1) Weigh 70 parts of polyurethane resin, 4 parts of isopropanol, 24 parts of rutile titanium dioxide, 1 part of leveling agent and 1 part of adhesion promoter. Disperse and mix the polyurethane resin and rutile titanium dioxide with a high-speed disperser under the conditions of 50 °C and a linear velocity of 8 m / s for 15 min, and then perform ultrasonic treatment for 8 min. Then add the remaining components to the mixture and disperse for 30 min until the system is uniform and stable to obtain the main agent component AVIa of the high-performance sunlight reflective coating.

[0078] (2) Weigh 77 parts of polyurethane resin, 5 parts of isopropanol, 16 parts of silica aerogel modified cesium tungsten bronze, 1 part of leveling agent and 1 part of adhesion promoter, and prepare the high near-infrared absorption coating AVIb by a similar method to (1).

[0079] (3) Weigh 76.5 parts of polyurethane resin, 8.5 parts of isopropanol, 13 parts of nano-tin antimony oxide modified vanadium oxide, 1 part of leveling agent and 1 part of adhesion promoter, and prepare the near-infrared modulation coating AVIc by a similar method to (1).

[0080] (4) Weigh 56 parts of polyurethane resin, 9 parts of isopropanol, 33 parts of thermochromic microcapsules, 1 part of leveling agent and 1 part of adhesion promoter, and prepare the thermoreversible color-changing coating AVId by a similar method to (1).

[0081] (5) Disperse and mix 93 parts of cyclohexane dimethylene diisocyanate and 7 parts of isopropanol using a high-speed disperser for 15 min until the system is homogeneous and stable, then the curing agent component BVI of the above coating can be obtained.

[0082] (6) Weigh the main agent AVIa and the curing agent BVI according to a mass ratio of 1:0.13, mix them evenly using mechanical stirring, and then prepare a solar spectrum high-reflectivity base layer with a dry film thickness of 45 μm through spraying construction.

[0083] (7) Weigh the main agent AVIb and the curing agent BVI according to a mass ratio of 1:0.15, mix them evenly using mechanical stirring, and then prepare a near-infrared absorption layer with a dry film thickness of 22 μm through spraying construction after the solar spectrum high-reflectivity base layer is dried and cured.

[0084] (8) Weigh the main agent AVIc and the curing agent BVI according to a mass ratio of 1:0.15, mix them evenly using mechanical stirring, and then prepare a near-infrared modulation layer with a dry film thickness of 18 μm through spraying construction after the near-infrared absorption layer is dried and cured.

[0085] (9) Weigh the main agent AVID and the curing agent BVI according to a mass ratio of 1:0.09, mix them evenly using mechanical stirring, and then prepare a thermochromic layer with a dry film thickness of 40 μm through spraying construction after the near-infrared modulation layer is dried and cured, thus obtaining the visible-near-infrared spectrum synergistic modulation thermoreversible color-changing coating VI with a composite structure.

[0086] Example 7: A thermoreversible color-changing composite coating VII capable of realizing visible-near-infrared spectrum synergistic modulation, and its preparation process is as follows:

[0087] (1) Weigh 62 parts of fluorocarbon resin, 4.7 parts of xylene, 32 parts of rutile titanium dioxide, 0.4 part of dispersant, 0.4 part of leveling agent and 0.5 part of defoamer. Disperse and mix the fluorocarbon resin and rutile titanium dioxide using a high-speed disperser at a linear velocity of 8 m / s and a temperature of 50 °C for 15 min, then perform ultrasonic treatment for 8 min, and then add the remaining components to the mixture and disperse for 30 min until the system is homogeneous and stable to obtain the main agent component AVIIa of the high-performance sunlight-reflecting coating.

[0088] (2) Weigh 80 parts of fluorocarbon resin, 3.7 parts of xylene, 15 parts of silica aerogel-modified cesium tungsten bronze, 0.4 part of dispersant, 0.4 part of leveling agent and 0.5 part of defoamer, and prepare the high near-infrared absorption coating AVIIb through a method similar to that in (1).

[0089] (3) Weigh 75 parts of fluorocarbon resin, 9.2 parts of xylene, 14.5 parts of nano-tin antimony oxide modified vanadium oxide, 0.4 part of dispersant, 0.4 part of leveling agent and 0.5 part of defoamer, and prepare the near-infrared modulation coating AVIIc by a similar method as in (1).

[0090] (4) Weigh 68 parts of fluorocarbon resin, 6.7 parts of xylene, 24 parts of thermochromic microcapsules, 0.4 part of dispersant, 0.4 part of leveling agent and 0.5 part of defoamer, and prepare the thermally reversible color-changing coating AVIId by a similar method as in (1).

[0091] (5) Disperse and mix 92 parts of hexamethylene diisocyanate and 8 parts of xylene using a high-speed disperser for 15 min until the system is uniform and stable, and then the curing agent component BVII of the above coating can be obtained.

[0092] (6) Weigh the main agent AVIIa and the curing agent BVII according to a mass ratio of 1:0.11, mix them evenly using mechanical stirring, and then prepare a solar spectrum high-reflectivity base layer with a dry film thickness of 60 μm by spraying construction.

[0093] (7) Weigh the main agent AVIIb and the curing agent BVII according to a mass ratio of 1:0.15, mix them evenly using mechanical stirring, and then prepare a near-infrared absorption layer with a dry film thickness of 20 μm by spraying construction after the solar spectrum high-reflectivity base layer is dried and cured.

[0094] (8) Weigh the main agent AVIIc and the curing agent BVII according to a mass ratio of 1:0.14, mix them evenly using mechanical stirring, and then prepare a near-infrared modulation layer with a dry film thickness of 12 μm by spraying construction after the near-infrared absorption layer is dried and cured.

[0095] (9) Weigh the main agent AVIId and the curing agent BVII according to a mass ratio of 1:0.13, mix them evenly using mechanical stirring, and then prepare a thermochromic layer with a dry film thickness of 35 μm by spraying construction after the near-infrared modulation layer is dried and cured, and then the visible-near-infrared spectrum synergistic modulation thermally reversible color-changing coating VII with a composite structure can be obtained.

[0096] Comparative Example 1: Commercially available reflective heat-insulating coating

[0097] Take a commercially available reflective heat-insulating coating of a certain brand to prepare a reflective heat-insulating temperature control coating and compare its performance with that of the example.

[0098] Comparative Example 2: Commercially available thermochromic coating

[0099] Take a commercially available thermochromic coating of a certain brand to prepare a thermochromic coating and compare its performance with that of the example.

[0100] Comparative Example 3: Self-made thermochromic temperature control coating VIII, and its preparation process is as follows:

[0101] (1) Weigh the main agent AIIa and the curing agent BII according to a mass ratio of 1:0.11. After mixing them evenly by mechanical stirring, prepare a solar spectrum highly reflective base layer with a dry film thickness of 40 μm through spraying construction.

[0102] (2)Weigh the main agent AIId and the curing agent BII according to a mass ratio of 1:0.12. After mixing them evenly by mechanical stirring, prepare a thermochromic layer with a dry film thickness of 40 μm through spraying construction after the solar spectrum highly reflective base layer is dried and cured, and then the self-made thermochromic temperature control coating VIII can be obtained.

[0103] Comparative Example 4: Self-made thermally responsive coating IX, and its preparation process is as follows:

[0104] (1)Weigh the main agent AIIa and the curing agent BII according to a mass ratio of 1:0.11. After mixing them evenly by mechanical stirring, prepare a solar spectrum highly reflective base layer with a dry film thickness of 40 μm through spraying construction.

[0105] (2)Weigh the main agent AIIc and the curing agent BII according to a mass ratio of 1:0.14. After mixing them evenly by mechanical stirring, prepare a near-infrared modulation layer with a dry film thickness of 20 μm through spraying construction after the solar spectrum highly reflective base layer is dried and cured.

[0106] (9)Weigh the main agent AIId and the curing agent BII according to a mass ratio of 1:0.12. After mixing them evenly by mechanical stirring, prepare a thermochromic layer with a dry film thickness of 40 μm through spraying construction after the near-infrared modulation layer is dried and cured, and then the visible-near-infrared spectrum synergistic modulation thermally reversible color-changing coating IX with a composite structure can be obtained.

[0107] Comparative Example 5: Prepare a thermally reversible color-changing composite coating X with unmodified aerogel cesium tungsten bronze, and its preparation process is as follows:

[0108] (1)Weigh 72.5 parts of polyurethane resin, 6.8 parts of ethanol, 19.5 parts of cesium tungsten bronze (silica aerogel is not used for co-ball milling modification during the preparation process), 0.6 part of dispersant and 0.6 part of leveling agent. Use a high-speed disperser to disperse and mix the polyurethane resin and cesium tungsten bronze at 50 °C and a linear velocity of 8 m / s for 15 min, and then perform ultrasonic treatment for 8 min. Then add the remaining components to the mixture and disperse for 30 min until the system is uniform and stable to obtain the main agent component AXb of the coating.

[0109] (2)Weigh the main agent AIVa and the curing agent BIV according to a mass ratio of 1:0.11. After mixing them evenly by mechanical stirring, prepare a solar spectrum highly reflective base layer with a dry film thickness of 45 μm through spraying construction.

[0110] (7) Weigh the main agent AXb and the curing agent BIV according to the mass ratio of 1:0.12. After mixing them evenly by mechanical stirring, spray them on the dried and cured high-reflection base layer of the solar spectrum to prepare a near-infrared absorption layer with a dry film thickness of 18 μm.

[0111] (8) Weigh the main agent AIVc and the curing agent BIV according to the mass ratio of 1:0.14. After mixing them evenly by mechanical stirring, spray them on the dried and cured near-infrared absorption layer to prepare a near-infrared modulation layer with a dry film thickness of 15 μm.

[0112] (9) Weigh the main agent AIVd and the curing agent BIV according to the mass ratio of 1:0.09. After mixing them evenly by mechanical stirring, spray them on the dried and cured near-infrared modulation layer to prepare a thermochromic layer with a dry film thickness of 40 μm, and then the visible-near-infrared spectrum synergistic modulation thermochromic reversible coating X with a composite structure can be obtained.

[0113] Comparative Example 6: Preparation of the thermochromic reversible composite coating XI without the content of nano-antimony tin oxide modified vanadium oxide. The preparation process is as follows:

[0114] (1) Weigh 80 parts of silicone resin, 6.3 parts of butyl acetate, 12.5 parts of vanadium oxide (vanadium oxide prepared without adding nano-antimony tin oxide for modification annealing during the preparation process), 0.6 part of defoamer and 0.6 part of thixotropic agent. Disperse and mix the silicone resin and vanadium oxide with a high-speed disperser at 50 °C and a linear velocity of 8 m / s for 15 min, and then perform ultrasonic treatment for 8 min. Then add the remaining components to the mixture and disperse for 30 min until the system is homogeneous and stable to obtain the main agent component AXIc of the coating.

[0115] (2) Weigh the main agent AVa and the curing agent BV according to the mass ratio of 1:0.09. After mixing them evenly by mechanical stirring, spray them to prepare a high-reflection base layer of the solar spectrum with a dry film thickness of 50 μm.

[0116] (3) Weigh the main agent AVb and the curing agent BV according to the mass ratio of 1:0.12. After mixing them evenly by mechanical stirring, spray them on the dried and cured high-reflection base layer of the solar spectrum to prepare a near-infrared absorption layer with a dry film thickness of 20 μm.

[0117] (4) Weigh the main agent AXIc and the curing agent BV according to the mass ratio of 1:0.12. After mixing them evenly by mechanical stirring, spray them on the dried and cured near-infrared absorption layer to prepare a near-infrared modulation layer with a dry film thickness of 15 μm.

[0118] (5) Weigh the main agent AVd and the curing agent BV according to a mass ratio of 1:0.11. After mixing them evenly by mechanical stirring, a thermochromic layer with a dry film thickness of 50 μm is prepared by spraying construction after drying and curing in the near-infrared modulation layer, and then the visible-near-infrared spectrum synergistic modulation thermally reversible color-changing coating XI with a composite structure can be obtained.

[0119] Comparative Example 7: Thermally reversible color-changing composite coating XII, and its preparation process is as follows:

[0120] (6) Weigh the main agent AVIIa and the curing agent BVII according to a mass ratio of 1:0.11. After mixing them evenly by mechanical stirring, a solar spectrum high-reflectivity base layer with a dry film thickness of 20 μm is prepared by spraying construction.

[0121] (7) Weigh the main agent AVIIb and the curing agent BVII according to a mass ratio of 1:0.15. After mixing them evenly by mechanical stirring, a near-infrared absorption layer with a dry film thickness of 40 μm is prepared by spraying construction after drying and curing on the solar spectrum high-reflectivity base layer.

[0122] (8) Weigh the main agent AVIIc and the curing agent BVII according to a mass ratio of 1:0.14. After mixing them evenly by mechanical stirring, a near-infrared modulation layer with a dry film thickness of 40 μm is prepared by spraying construction after drying and curing on the near-infrared absorption layer.

[0123] (9) Weigh the main agent AVIId and the curing agent BVII according to a mass ratio of 1:0.13. After mixing them evenly by mechanical stirring, a thermochromic layer with a dry film thickness of 20 μm is prepared by spraying construction after drying and curing on the near-infrared modulation layer, and then the visible-near-infrared spectrum synergistic modulation thermally reversible color-changing coating XII with a composite structure can be obtained.

[0124] Effect description:

[0125] The visible-near-infrared spectrum synergistic modulation thermally reversible color-changing composite coatings prepared in Examples 1-7 of the present invention were used for performance test comparison with the comparative coatings of Comparative Examples 1-7. The solar light reflection spectra of the coatings at 5 °C and 50 °C were tested, and the visible light modulation ability (300 nm - 780 nm), near-infrared modulation ability (780 nm - 2500 nm) and solar light modulation ability (the difference in solar light reflectance) of the coatings at 5 °C and 50 °C were calculated. And the modulation performance stability after 200 high-low temperature cycles was tested, and the relevant test results were sorted into Table 1:

[0126] Table 1 Test results of the performance of the thermally reversible color-changing composite coating

[0127] Sample Modulation performance in the visible light band Modulation performance in the near-infrared band Modulation performance of solar reflectance Retention rate of modulation performance after 200 cycles Example 1 68% 40% 51% 95% Example 2 64% 38% 48% 98% Example 3 65% 45% 46% 97% Example 4 65% 42% 48% 98% Example 5 70% 36% 45% 97% Example 6 72% 38% 52% 96% Example 7 66% 42% 46% 98% Comparative Example 1 0% 0% 0% / Comparative Example 2 65% 1% 25% 68% Comparative Example 3 82% 1% 29% 95% Comparative Example 4 70% 1% 26% 95% Comparative Example 5 50% 23% 30% 96% Comparative Example 6 48% 20% 24% 95% Comparative Example 7 30% 33% 22% 96%

[0128] As can be seen from the data in Table 1, the thermally reversible color-changing composite coating with visible-near infrared spectrum co-modulation prepared in the examples can simultaneously achieve modulation performance at the level of 60% - 70% in the visible light band and 35% - 40% in the near infrared band under the low temperature condition of 5°C and the high temperature condition of 50°C. This enables the overall modulation rate of the solar reflectance ratio to reach nearly 50%, showing a significant improvement compared to traditional thermochromic temperature control coatings. This is achieved through the synergistic effect of multiple functional structures such as highly reflective, near infrared absorbing, near infrared modulating, and thermochromic structures that are ingeniously designed. Moreover, the system shows no significant degradation in modulation and temperature control performance after 200 color-changing cycles, indicating better long-term service performance. The test results confirm that the examples of the present invention have strong practical value.

[0129] Comparative Example 1 is a highly reflective heat-insulating coating without temperature response performance, which has the same spectral performance under different conditions, so it is only applicable to reflective cooling under high temperature conditions. Comparative Examples 2 and 3 are composite coatings of thermochromic coatings and highly reflective coatings. Since the room temperature color-changing substances in them are organic color-changing materials, they can only achieve the adjustment of the reflectance ratio in the visible light band and do not have the adjustment performance in the near infrared band. Even for the self-made color-changing coating, although it can achieve a modulation performance of more than 80% in the visible light band, its overall solar reflectance ratio modulation performance is still much lower than that of the examples.

[0130] In Comparative Example 4, the near infrared absorption layer prepared with cesium tungsten bronze-based raw materials as fillers is missing. Therefore, although there is a vanadium oxide layer to control the near infrared transmittance at different temperatures, the increased transmitted near infrared band is still reflected by the bottom layer. Thus, it also does not have near infrared modulation performance, and its modulation performance in the visible light band is lower than that of the pure reversible color-changing coating. This is because the vanadium oxide layer also absorbs a small part of visible light in the high temperature environment.

[0131] In Comparative Example 5, cesium tungsten bronze without silica aerogel modification is used as the filler for the near infrared absorption layer. It has a relatively obvious absorption of visible light at high temperature, and the absorption rate in the near infrared band at low temperature is also insufficient. Therefore, its modulation performance in both bands is significantly lower than that of the examples, and the modulation performance of the overall solar reflectance ratio is also insufficient. In Comparative Example 6, vanadium oxide without nano-antimony tin oxide modification is used as the filler for the near infrared modulation layer. It has a relatively obvious absorption of visible light at high temperature, and the difference in the transmittance of the near infrared band before and after phase change at different temperatures is small. Therefore, its modulation performance in both bands is also significantly lower than that of the examples, and the modulation performance of the overall solar reflectance ratio is insufficient.

[0132] In Comparative Example 7, the thicknesses of the high-reflection layer and the reversible color-changing layer are relatively low, while the thicknesses of the near-infrared absorption layer and the near-infrared modulation layer are relatively high. This results in a significant increase in the absorption in the visible light band and a significant decrease in the regulation performance. Moreover, the near-infrared modulation performance also decreases due to the thinning of the reflection layer. Therefore, the overall performance decreases significantly.

[0133] As described above, the above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A thermoreversible color-changing composite coating capable of realizing coordinated modulation of visible and near-infrared spectra, characterized in that The multilayer composite structure temperature control coating is composed of a solar spectrum high reflection layer, a near-infrared absorption layer, a near-infrared modulation layer and a thermochromic layer; wherein the solar light high reflection layer is prepared from a high-performance solar light reflection coating with a rutile titanium dioxide filler; wherein the near-infrared absorption layer is prepared from a high near-infrared absorption coating with a silica aerogel-modified cesium tungsten bronze filler; wherein the near-infrared modulation layer is prepared from a near-infrared modulation coating with a nano-tin oxide antimony-modified vanadium dioxide filler; wherein the thermochromic layer is prepared from a thermoreversible color-changing coating with a thermoreversible color-changing microcapsule filler; wherein the film thicknesses of the solar spectrum high reflection layer, the near-infrared absorption layer, the near-infrared modulation layer and the thermochromic layer are 40 μm-60 μm, 15 μm-25 μm, 10 μm-20 μm and 30 μm-50 μm, respectively.

2. A thermoreversible color-changing composite coating capable of realizing coordinated modulation of visible and near infrared spectra according to claim 1, characterized in that The high-performance sunlight reflective coating is composed of an A1 main agent and a B1 curing agent; wherein the A1 main agent is prepared by mixing a base resin, a rutile titanium dioxide filler, a solvent and a functional additive; the mass contents of the base resin, the rutile titanium dioxide filler, the solvent and the functional additive are 55%-72%, 22%-33%, 3%-10% and 1%-4% respectively, based on the total mass of the A1 main agent; the B1 curing agent is prepared from a curing agent and a solvent, and the mass contents of the curing agent and the solvent are 85%-100% and 0-15% respectively; the mass ratio of the A1 main agent to the B1 curing agent is 1:(0.08-0.22).

3. A thermoreversible color-changing composite coating capable of realizing coordinated modulation of visible and near infrared spectra according to claim 1, characterized in that The high near-infrared absorption coating is composed of an A2 main agent and a B2 curing agent; wherein the A2 main agent is prepared from a base resin, a silica aerogel-modified cesium tungsten bronze filler, a solvent and a functional additive; the mass contents of the base resin, the silica aerogel-modified cesium tungsten bronze filler, the solvent and the functional additive are 70%-80%, 15%-20%, 3%-10% and 1%-3%, respectively, based on the total mass of the A2 main agent; the B2 curing agent is prepared from a curing agent and a solvent, and the mass contents of the curing agent and the solvent are 85%-100% and 0-15%, respectively; the mass ratio of the A2 main agent to the B2 curing agent is 1:(0.12-0.25).

4. A thermoreversible color-changing composite coating capable of realizing coordinated modulation of visible and near infrared spectra according to claim 1, characterized in that The preparation method of the silica aerogel modified cesium tungsten bronze is as follows: (1) tungsten chloride and ethanol are mixed and completely dissolved, and then cesium hydroxide is added and stirred for 5 minutes, and finally acetic acid is added and stirred evenly to obtain a reaction precursor solution; (2) the reaction precursor solution is transferred into a reactor, heated at 220°C~240°C for 24 hours, and the precipitate is centrifuged, washed and vacuum dried to obtain cesium tungsten bronze powder; (3) the cesium tungsten bronze powder and a certain amount of silica aerogel are mixed evenly in N,N-dimethylformamide and ball milled at a speed of 600 rpm for 30 minutes to obtain silica aerogel modified cesium tungsten bronze; wherein the mass ratio of cesium tungsten bronze to silica aerogel is 1:(0.3~0.6).

5. A thermoreversible color-changing composite coating capable of realizing coordinated modulation of visible and near infrared spectra according to claim 1, characterized in that The near-infrared modulation coating is composed of an A3 main agent and a B3 curing agent; wherein the A3 main agent is prepared from a base resin, a nano-tin antimony oxide modified vanadium dioxide filler, a solvent and a functional additive; the mass contents of the base resin, the nano-tin antimony oxide modified vanadium dioxide filler, the solvent and the functional additive are 75%-85%, 10%-15%, 3%-10% and 1%-3% respectively, based on the total mass of the A3 main agent; the B3 curing agent is prepared from a curing agent and a solvent, and the mass contents of the curing agent and the solvent are 85%-100% and 0-15% respectively; the mass ratio of the A3 main agent to the B3 curing agent is 1:(0.14-0.25).

6. A thermoreversible color-changing composite coating capable of realizing coordinated modulation of visible and near infrared spectra according to claim 1, characterized in that The preparation method of nano-tin oxide antimony modified vanadium dioxide is as follows: (1) vanadium pentoxide and oxalic acid dihydrate are uniformly dissolved in deionized water in a ratio of 1:2 in terms of amount of substance, and after the dissolution is completed, magnesium sulfate is added and stirred for 30 minutes to obtain a reaction precursor solution; (2) the reaction precursor solution is transferred to a hydrothermal reactor, reacted at 240°C for 10 hours, and then ultrasonically cleaned three times with water and ethanol respectively, vacuum filtered at 60°C and dried for 12 hours, and ground to obtain magnesium-doped vanadium dioxide powder; (3) the vanadium dioxide powder and nano-tin oxide antimony are uniformly mixed in water and ball milled at a speed of 400rpm~600rpm for 30 minutes; (4) in a nitrogen atmosphere, the ball-milled powder is heat-treated at a temperature of 520℃~600℃ for 3 hours to obtain nano-tin oxide antimony modified vanadium dioxide; wherein the doping amount of magnesium element is 1.5%~2.3%, based on the mass of vanadium dioxide; the mass ratio of vanadium dioxide to nano-tin oxide antimony is 1:(0.8~1.4).

7. A thermoreversible color-changing composite coating capable of realizing coordinated modulation of visible and near infrared spectra according to claim 1, characterized in that The thermoreversible color-changing coating is composed of an A4 main agent and a B4 curing agent; wherein the A4 main agent is prepared from a base resin, a thermoreversible color-changing microcapsule filler, a solvent and a functional additive; the mass contents of the base resin, the thermoreversible color-changing microcapsule filler, the solvent and the functional additive are 55%-72%, 20%-35%, 3%-10% and 1%-4% respectively, based on the total mass of the A4 main agent; the B4 curing agent is prepared from a curing agent and a solvent, and the mass contents of the curing agent and the solvent are 85%-100% and 0-15% respectively; the mass ratio of the A4 main agent to the B4 curing agent is 1:(0.09-0.22).

8. The thermoreversible color-changing composite coating capable of realizing coordinated modulation of visible and near infrared spectra according to claim 1, characterized in that The preparation method of the thermoreversible color-changing microcapsules comprises the following steps: (1) dissolving a ternary thermoreversible color-changing core material consisting of a pigment, a color developer and a solvent, adding the solvent to water containing an emulsifier, and performing high-speed emulsification at 65°C under heating conditions to obtain a thermoreversible color-changing emulsion; (2) dripping a resin prepolymer into the reversible color-changing emulsion at a constant speed under heating and stirring conditions, and after the dripping is completed, in-situ polymerizing at 85°C for 1 hour, filtering and drying the suspension after the reaction to obtain a thermoreversible color-changing microcapsule; wherein the pigment is at least one of crystal violet lactone, 2-phenylamino-3-methyl-6-dibutylaminofluoran and 3',6'-dimethoxyfluoran; The developer is at least one of bisphenol A, bisphenol F, and bisphenol S; the solvent is at least one of tetradecanol, tricaprin, methyl octadecanoate, and ethyl octadecanoate; the mass concentration of the pigment molecule is 0.8%~6%, and the mass ratio of the pigment to the developer is 1:(1.5~4) based on the total mass of the color-changing core material; the emulsifier is at least one of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, and styrene maleic anhydride copolymer sodium salt, and the mass concentration is 0.5%~1%; the resin prepolymer is at least one of melamine resin prepolymer, urea-formaldehyde resin prepolymer, and methyl melamine formaldehyde resin prepolymer, and the amount used is 5~13% of the total mass of the thermoreversible color-changing microcapsules.

9. A thermoreversible color-changing composite coating capable of realizing coordinated modulation of visible and near infrared spectra according to claim 1, characterized in that The preparation methods of the high-performance sunlight reflective coating, high near-infrared absorption coating, near-infrared modulation coating and thermo-reversible color-changing coating are as follows: (1) Weigh appropriate amounts of each component, use a high-speed disperser to disperse and mix the base resin and filler for 15 min at 40°C to 60°C and a linear speed of 6 m / s to 10 m / s, then perform ultrasonic treatment for 4 min to 10 min, then add the remaining components to the mixture and disperse for 30 min until the system is uniform and stable to obtain the coating main agent component; (2) The isocyanate and the solvent are dispersed and mixed using a high-speed disperser for 15 minutes until the system is uniform and stable to obtain the curing agent component; The matrix resin is at least one of silicone resin, fluorocarbon resin and polyurethane resin; the solvent is at least one of xylene, acetone, ethanol, isopropanol, butyl acetate and propylene glycol methyl ether acetate; the functional additive is at least one of a dispersant, a defoamer, a leveling agent, an adhesion promoter and a thixotropic agent; the isocyanate is at least one of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, cyclohexane dimethylene diisocyanate, xylene diisocyanate, polymethylene polyphenyl polyisocyanate, hexamethylene diisocyanate trimer and hexamethylene diisocyanate biuret; the solvent is at least one of xylene, acetone, ethanol, isopropanol, butyl acetate and propylene glycol methyl ether acetate.

10. The thermoreversible color-changing composite coating capable of realizing coordinated modulation of visible and near infrared spectra according to claim 1, characterized in that The coating is prepared by using a relevant molding method to sequentially mold a high-performance solar reflective coating, a high near-infrared absorption coating, a near-infrared modulation coating, and a thermo-induced reversible color-changing coating into a film layer of suitable thickness on a substrate; wherein the molding method can be any one of screen printing, spraying, cast coating, and roller coating; each coating molding needs to be dried at room temperature for 24 hours and then placed at 60°C for curing for 12 hours, and the next coating molding is carried out after the previous coating molding is completed; The thermoreversible color-changing composite coating can be used as a surface temperature control material for structures such as houses, buildings, factories, cold storages, industrial storage tanks, transportation infrastructure, and small components.