A thermotropic reversible color-changing temperature-controlled coating based on hair structure microcapsules and its preparation method

Abstract

This invention discloses a thermotropic reversible color-changing temperature-controlled coating based on hair-structured microcapsules and its preparation method. This thermotropic reversible color-changing temperature-controlled coating is a two-layer structure consisting of a high-reflectivity heat-insulating layer and a high-thermal-conductivity thermotropic layer. The high-thermal-conductivity thermotropic layer is prepared using thermotropic reversible color-changing microcapsules with a hair-like surface structure and nano-silica as composite fillers. The hair fiber microcapsules, on the one hand, enhance its dispersibility, effectively preventing microcapsule aggregation during dispersion; on the other hand, the addition of nano-silica particles during surface fiber modification effectively improves heat conduction between the microcapsules, resulting in faster and more uniform temperature changes in the surface reversible color-changing layer, and significantly improving the uniformity of color change in the system. This coating exhibits excellent performance and is of great significance for related technological advancements and industrial development.

Description

Technical Field

[0001] This invention belongs to the field of fine polymer materials, specifically relating to the preparation of a thermotropic reversible color-changing temperature-controlled coating based on hair structure microcapsules and its application in structural temperature control in transportation, construction, machinery, chemical and other fields. Background Technology

[0002] For engineering structures operating in exposed environments, solar radiation is the primary external energy source, leading to significant temperature fluctuations. Therefore, using highly reflective temperature-controlling materials on the surface is a common measure to reduce the impact of solar radiation on structural temperature and lower energy consumption for temperature control. However, these highly reflective materials only have a cooling effect; in conditions such as winter when the structure requires solar irradiation for heating, they still reflect light, which has a significant negative impact on overall temperature control and energy efficiency, hindering the application prospects of this type of material in western and northern my country. Therefore, developing intelligent temperature-controlling materials with different surface photothermal properties for different scenarios is of significant economic and social importance and brings new development opportunities for the future application research of passive surface temperature control materials.

[0003] The photothermal properties of surface temperature-controlled materials are closely related to their appearance color. Therefore, adjusting the photothermal conversion performance of temperature-controlled materials under different conditions by changing their appearance color is highly feasible. Among these, thermochromic materials with temperature as the main color control factor have become an important research focus. Among numerous thermochromic materials, powder microcapsules prepared based on a ternary organic reversible thermochromic material system composed of pigments, color developers, and solvents have become one of the mainstream commercial products due to their advantages of sensitive color-changing reactions, narrow color-changing temperature range, high selectivity and adjustability of color and temperature range, low price, and long lifespan. Currently, researchers have used it as a pigment to prepare coatings with thermochromic properties and have applied it to areas such as intelligent temperature control, temperature monitoring, thermochromic anti-counterfeiting, and temperature-changing clothing.

[0004] Patent CN117801627A discloses a reversible thermochromic epoxy powder coating. By adding thermochromic pigments, the powder coating acquires thermochromic properties, exhibiting good leveling, no pinholes, uniform color distribution, and reversible temperature indication after film formation. Patent CN112980248B discloses a thermochromic liquid crystal microcapsule ink and color-changing coating. Using cholesteric liquid crystal as the core material and polyurethane resin as the wall material, thermochromic liquid crystal microcapsules are prepared, achieving color changes between 40-65℃ for direct temperature measurement. Patent CN117050654A discloses a reversible color-changing coating. Through component proportioning and screening, a color-changing coating with rich colors is prepared, exhibiting high color-changing sensitivity, a simple and convenient preparation process, good adhesion, and excellent coating effect, suitable for temperature detection of thermal defects in disconnector contacts. Patent CN116285442B discloses a carbon-negative, self-temperature-regulating thermochromic coating. By modifying the reversible color-changing microcapsules with titanium sol, its UV aging resistance is improved while enhancing the bonding force of other inorganic carbonized cementitious materials, resulting in excellent coating performance.

[0005] As can be seen from the above description, existing thermochromic coatings already possess color-changing properties and certain practical value. However, from the perspective of overall technological development, thermochromic coatings still face some challenges. Firstly, to ensure good temperature control, the thermal conductivity of the coating is typically low, leading to significant differences in heating and cooling rates at different locations. This can cause patchy phenomena during the color-changing process, affecting aesthetics and practicality. Secondly, the dispersion of color-changing microcapsules is often difficult. At low speeds, uniform dispersion is challenging, while at high speeds, microcapsules may rupture and leak, causing difficulties in coating production. Furthermore, the high cost and large quantity of microcapsules significantly increase coating costs, hindering widespread application. Therefore, based on relevant research, further development of novel thermochromic coatings to improve system dispersion uniformity, color-changing uniformity, and color-developing ability, while reducing preparation costs, is crucial for promoting the further development of related technologies and advancing the industry. Summary of the Invention

[0006] The purpose of this invention is to solve the above-mentioned problems and provide a thermotropic reversible color-changing temperature-controlled coating based on hair structure microcapsules and its preparation method.

[0007] The thermochromic temperature-controlled coating based on hair-structured microcapsules of this invention is a two-layer structure consisting of a high-reflectivity heat insulation layer and a high-thermal-conductivity thermochromic layer. The high-reflectivity heat insulation layer is prepared by a high-performance reflective heat insulation coating using rutile titanium dioxide and hollow glass microspheres as fillers. The high-thermal-conductivity thermochromic layer is prepared by a high-thermal-conductivity thermochromic coating using thermochromic microcapsules with hair-structured surfaces and nano-silica as composite fillers. The dry film thicknesses of the high-reflectivity heat insulation layer and the high-thermal-conductivity thermochromic layer are 80-120 μm and 30-50 μm, respectively.

[0008] The high thermal conductivity thermochromic coating in this thermochromic reversible color-controlling coating consists of component A1 (main agent) and component B1 (curing agent). Component A1 (main agent) is prepared from matrix resin, hair-structured microcapsules and nano-silica composite filler, solvent, functional additives and rheology modifier. Component B (curing agent) is prepared from curing agent and solvent. The mass ratio of hair-structured microcapsules to nano-silica in the composite filler is 1:(0.3~0.6); the mass ratio of component A1 (main agent) to component B (curing agent) is 1:(0.08~0.22).

[0009] The preparation method of the filler in the high thermal conductivity thermotropic reversible color-changing coating includes the following steps:

[0010] (1) A thermochromic emulsion is obtained by dissolving a ternary thermochromic core material composed of pigment, color developer and solvent and adding it to deionized water containing emulsifier and emulsifying it at high speed under heating conditions of 65°C.

[0011] (2) Under heating and stirring conditions, the resin prepolymer is added dropwise to the reversible color-changing emulsion at a constant rate. After the addition is complete, the mixture is polymerized in situ at 85°C for 1 hour. The suspension after the reaction is filtered and dried to obtain thermo-reversible color-changing microcapsules.

[0012] (3) Mix N,N-methylenebisacrylamide, ethanol, toluene, RAFT reagent and initiator until completely dissolved, add reversible color-changing microcapsules and nano silica to them and disperse them evenly by high-speed stirring, carry out in-situ RAFT precipitation polymerization in a nitrogen environment at 80℃ for 24h, and then filter and dry to obtain a mixed filler of reversible color-changing microcapsules and nano silica with nano hair structure on the surface.

[0013] In this preparation method, the pigment is at least one of crystal violet lactone, 2-phenylamino-3-methyl-6-dibutylaminofluorane, and 3',6'-dimethoxyfluorane; the color developer is at least one of bisphenol A, bisphenol F, and bisphenol S; the solvent contains at least one of tetradecyl alcohol, decanoic acid triglyceride, methyl stearate, and ethyl stearate; the mass concentration of the pigment molecules is 0.8-6%, and the mass ratio of pigment to color developer is 1:(1.5-4); the emulsifier is at least one of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, and sodium salt of styrene-maleic anhydride copolymer, with a mass concentration of 0.5-1%; the resin prepolymer is at least one of melamine resin prepolymer, urea-formaldehyde resin prepolymer, methyl melamine-formaldehyde resin prepolymer, polyurethane resin prepolymer, and acrylic resin, and the amount used is 5-13% of the total amount.

[0014] In this preparation method, the mass concentration of N,N-methylenebisacrylamide is 0.5-1.5%, the mass concentration of ethanol is 1.5-3%, the RAFT reagent is at least one of dithiobenzoate, trithiocarbonate, and dithiocarbamate, and its amount is 8-12% of the monomer amount; the initiator is at least one of azobisisobutyronitrile, azobisisoheptanenitrile, benzoyl peroxide, and lauroyl peroxide, and its amount is 1-2% of the monomer amount.

[0015] The high-performance reflective heat-insulating coating in this thermotropic reversible color-changing temperature-controlled coating consists of component A2 (main agent) and component B (curing agent). Component A2 (main agent) is prepared from a matrix resin, rutile titanium dioxide, hollow glass microspheres, solvent, functional additives, and rheology modifiers. The mass ratio of rutile titanium dioxide to hollow glass microspheres is 1:(0.8~1.2). The mass ratio of component A2 (main agent) to component B (curing agent) is 1:(0.08~0.22).

[0016] In the two main components of the thermotropic reversible color-changing temperature-controlled coating, the contents of the matrix resin, filler, solvent, functional additives, and rheology modifier are 50-72%, 22-33%, 3-10%, 0.5-3.5%, and 0.5-2.0%, respectively, based on the total mass of the main components; wherein the matrix resin is at least one of silicone resin, fluorocarbon resin, polyurethane resin, and acrylic modified polyurethane resin; wherein the solvent is at least one of xylene, methyl ethyl ketone, n-butanol, butyl acetate, dimethylformamide, propylene glycol methyl ether acetate, and water; wherein the functional additive is at least one of dispersant, defoamer, leveling agent, and adhesion promoter; wherein the rheology modifier is at least one of bentonite, hydrated magnesium silicate, fumed silica, and polymer wax.

[0017] In the curing agent of component B of the two coatings in this thermotropic reversible color-changing temperature-controlled coating, the content of isocyanate and solvent is 85%-100% and 0-15% respectively, based on the total mass of component B; wherein the isocyanate is at least one selected from toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, cyclohexane diisocyanate, phenyl diisocyanate, hydrophilic HDI polyisocyanate, polymethylene polyphenyl polyisocyanate, hexamethylene diisocyanate trimer and hexamethylene diisocyanate biuret; the solvent is at least one selected from xylene, methyl ethyl ketone, n-butanol, butyl acetate, dimethylformamide, propylene glycol methyl ether acetate and water.

[0018] The preparation method of the two coatings in the thermotropic reversible color-changing temperature-controlled coating includes the following steps: (1) Weigh the appropriate mass of each component, disperse and mix the matrix resin and filler using a high-speed disperser at 40~60℃ and a linear velocity of 6-10m / s for 15min, then perform ultrasonic treatment for 4~10min, and then add the remaining components to the mixture and disperse for 30min until the system is homogeneous and stable to obtain the coating main component; (2) Disperse and mix the isocyanate and solvent using a high-speed disperser for 15min until the system is homogeneous and stable to obtain the curing agent component.

[0019] The two coatings in this thermotropic reversible color-changing temperature-controlled coating can be applied in the field using any one of the following methods: spraying, dipping, roller coating, or brushing.

[0020] The positive effects of the thermotropic reversible color-changing temperature-controlled coating based on hair structure microcapsules of the present invention are:

[0021] The thermochromic color-changing temperature-controlling coating prepared in this invention is achieved through a double-layer structure. The bottom high-reflectivity heat-insulating layer has extremely strong reflective heat-insulating properties. The top thermochromic color-changing layer is colorless and transparent at high temperatures, fully demonstrating the reflective heat-insulating properties of the bottom layer, while it turns black at low temperatures, covering the bottom layer coating and exhibiting heat absorption and insulation properties. Compared with traditional thermochromic coatings, the double-layer design reduces the amount of reversible color-changing material used, significantly improves the color-changing ability and temperature control effect of the system, and has excellent technical and economic advantages.

[0022] Furthermore, in the surface thermotropic reversible color-changing layer, hair-like nanofibers are modified on the surface of traditional spherical microcapsules through RAFT precipitation polymerization. This not only gives it stronger dispersibility and effectively avoids microcapsule aggregation during the dispersion process, but also, due to the addition of nano-silica particles during the surface modification process, these particles can effectively improve the heat conduction between microcapsules distributed between different particles of the hair, making the temperature change of the surface reversible color-changing layer faster and more uniform, and significantly improving the uniformity of color change of the system.

[0023] As can be seen from the above description, the thermotropic reversible color-changing coating technology has a clear mechanism of action, a simple production process, excellent product performance, strong durability, low cost, and is suitable for large-scale production applications. It is of great significance for the preparation, research and development of surface passive temperature control materials with intelligent temperature control function and their promotion in related application fields. Attached Figure Description

[0024] Figure 1 This is a scanning electron microscope image of thermo-reversible color-changing microcapsules with hair-like fiber structures on their surface. Detailed Implementation

[0025] The present invention will now be described in further detail with reference to specific embodiments.

[0026] Example 1: A thermotropic reversible color-changing temperature-controlled coating A based on hair structure microcapsules, the preparation process of which is as follows:

[0027] (1) Under heating conditions, 3.5 parts crystal violet lactone, 7 parts bisphenol A and 89.5 parts tetradecyl alcohol were completely dissolved to prepare a clear ternary color-changing system oil phase. The oil phase was added to water containing 0.8% sodium dodecyl sulfate at 65°C to prepare a thermo-reversible color-changing emulsion. Then, 8 parts melamine resin prepolymer were added dropwise to the emulsion under heating conditions and polymerized in situ at 85°C for 1 hour. The suspension after the reaction was filtered and dried to obtain thermo-reversible color-changing microcapsules a1.

[0028] (2) 1.5 parts of N,N-methylenebisacrylamide, 4.5 parts of ethanol, 295 parts of toluene, 0.25 parts of trithiocarbonate and 0.035 parts of azobisisobutyronitrile were mixed evenly under ultrasonic conditions and completely dissolved at 80°C. 20 parts of thermochromic microcapsules a1 and 10 parts of nano silica particles were added to the mixture and dispersed evenly by high-speed stirring. After in-situ RAFT precipitation polymerization was carried out in a nitrogen environment at 80°C for 24 hours, the mixture was filtered and dried to obtain a mixed filler a of reversible color-changing microcapsules and nano silica with nano hair structure on the surface.

[0029] (3) Weigh 57 parts of fluorocarbon resin, 9 parts of xylene, 28 parts of mixed filler a, 0.5 parts of dispersant, 0.5 parts of leveling agent, 0.6 parts of defoamer and 0.9 parts of hydrated magnesium silicate. Use a high-speed disperser to disperse and mix the fluorocarbon resin and mixed filler a at 40~60℃ and a linear velocity of 6-10m / s for 15min. Then, perform ultrasonic treatment for 4~10min. Add the remaining components to the mixture and disperse for 30min until the system is homogeneous and stable to obtain the main component Aa1 of the high thermal conductivity thermo-reversible color-changing coating.

[0030] (4) 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 minutes until the system is homogeneous and stable to obtain the high thermal conductivity thermotropic reversible color-changing coating curing agent component Ab1.

[0031] (5) Weigh 62 parts of polyurethane resin, 7.3 parts of propylene glycol methyl ether acetate, 15 parts of rutile titanium dioxide, 13 parts of hollow glass microspheres, 0.4 parts of dispersant, 0.4 parts of leveling agent, 0.5 parts of defoamer and 1.35 parts of fumed silica. Use a high-speed disperser to disperse and mix the polyurethane resin, rutile titanium dioxide and hollow glass microspheres at 40~60℃ and a linear velocity of 6-10m / s for 15min. Then, perform ultrasonic treatment for 4~10min. Add the remaining components to the mixture and disperse for 30min until the system is homogeneous and stable to obtain the main component Aa2 of the high reflectivity heat insulation coating.

[0032] (6) Disperse and mix 30 parts of toluene diisocyanate, 65 parts of toluene diisocyanate trimer and 5 parts of propylene glycol methyl ether acetate using a high-speed disperser for 15 minutes until the system is homogeneous and stable to obtain curing agent component Ab2.

[0033] (7) Weigh Aa2 main agent and Ab2 curing agent at a mass ratio of 1:0.13, mix them evenly with mechanical stirring, and then prepare a high reflective heat insulation layer with a dry film thickness of 100μm by spraying.

[0034] (8) Weigh Aa1 main agent and Ab1 curing agent according to a mass ratio of 1:0.15, mix them evenly with mechanical stirring, and then prepare a high thermal conductivity thermo-reversible color-changing layer with a dry film thickness of 40μm by spraying after the high reflective heat insulation layer is dried. This will give you a double-layer thermo-reversible color-changing temperature control coating A.

[0035] Example 2: A thermotropic reversible color-changing temperature-controlled coating B based on hair structure microcapsules, the preparation process of which is as follows:

[0036] (1) Under heating conditions, 2.5 parts of 2-phenylamino-3-methyl-6-dibutylaminofluorane, 5.5 parts of bisphenol S and 92 parts of glyceryl tridecanoate were completely dissolved to prepare a clear ternary color-changing system oil phase. The oil phase was added to water containing 0.9% sodium salt of styrene-maleic anhydride copolymer at 65°C to prepare a thermo-reversible color-changing emulsion. Then, 12 parts of urea-formaldehyde resin prepolymer were added dropwise to the emulsion under heating conditions and polymerized in situ at 85°C for 1 hour. The thermo-reversible color-changing microcapsules b1 were obtained by filtering and drying the suspension after the reaction.

[0037] (2) 1.5 parts of N,N-methylenebisacrylamide, 4.5 parts of ethanol, 295 parts of toluene, 0.25 parts of trithiocarbonate and 0.035 parts of azobisisobutyronitrile were mixed evenly under ultrasonic conditions and completely dissolved at 80°C. 20 parts of thermochromic microcapsules b1 and 8 parts of nano silica particles were added to the mixture and dispersed evenly by high-speed stirring. After in-situ RAFT precipitation polymerization was carried out in a nitrogen environment at 80°C for 24 hours, the mixture was filtered and dried to obtain the mixed filler b of reversible color-changing microcapsules and nano silica with nano hair structure on the surface.

[0038] (3) Weigh 65 parts of waterborne polyurethane resin, 7 parts of water, 24 parts of mixed filler b, 0.5 parts of dispersant, 0.4 parts of defoamer and 0.6 parts of fumed silica. Use a high-speed disperser to disperse and mix the waterborne polyurethane resin and mixed filler b at 40~60℃ and a linear velocity of 6-10m / s for 15min. Then, perform ultrasonic treatment for 4~10min. Add the remaining components to the mixture and disperse for 30min until the system is homogeneous and stable to obtain the main component Ba1 of the high thermal conductivity thermo-reversible color-changing coating.

[0039] (4) Hydrophilic HDI polyisocyanate was used as component Bb1 of the curing agent for the high thermal conductivity thermo-reversible color-changing coating.

[0040] (5) The preparation process of the main component Aa2 and the curing agent component Ab2 of the high reflectivity heat insulation coating is as described in Example 1.

[0041] (6) Weigh Aa2 main agent and Ab2 curing agent at a mass ratio of 1:0.13, mix them evenly with mechanical stirring, and then prepare a high-reflectivity heat insulation layer with a dry film thickness of 100μm by spraying.

[0042] (7) Weigh Ba1 main agent and Bb1 curing agent according to a mass ratio of 1:0.11, mix them evenly with mechanical stirring, and then prepare a high thermal conductivity thermo-reversible color-changing layer with a dry film thickness of 40μm by spraying after the high reflective heat insulation layer is dried. This will give you a double-layer thermo-reversible color-changing temperature control coating B.

[0043] Example 3: A thermotropic reversible color-changing temperature-controlled coating C based on hair structure microcapsules, the preparation process of which is as follows:

[0044] (1) Under heating conditions, 3.2 parts of crystal violet lactone, 8 parts of bisphenol F and 88.8 parts of methyl stearate were completely dissolved to prepare a clear ternary color-changing system oil phase. The oil phase was added to water containing 0.75% sodium dodecyl sulfate at 65°C to prepare a thermo-reversible color-changing emulsion. Then, 8.4 parts of methyl melamine formaldehyde resin prepolymer were added dropwise to the emulsion under heating conditions and polymerized in situ at 85°C for 1 hour. The suspension after reaction was filtered and dried to obtain thermo-reversible color-changing microcapsules c1.

[0045] (2) 1.5 parts of N,N-methylenebisacrylamide, 4.5 parts of ethanol, 295 parts of toluene, 0.25 parts of trithiocarbonate and 0.035 parts of azobisisobutyronitrile were mixed evenly under ultrasonic conditions and completely dissolved at 80°C. 20 parts of thermochromic microcapsules c1 and 9 parts of nano silica particles were added to the mixture and dispersed evenly by high-speed stirring. After in-situ RAFT precipitation polymerization was carried out in a nitrogen environment at 80°C for 24 hours, the mixture was filtered and dried to obtain the mixed filler c of reversible color-changing microcapsules and nano silica with nano hair structure on the surface.

[0046] (3) Weigh 55 parts of fluorocarbon resin, 8.5 parts of acetone, 29 parts of mixed filler c, 1 part of dispersant, 1 part of leveling agent, 1 part of defoamer and 1.3 parts of bentonite. Use a high-speed disperser to disperse and mix the fluorocarbon resin and mixed filler c at 40~60℃ and a linear velocity of 6-10m / s for 15min. Then, perform ultrasonic treatment for 4~10min. Add the remaining components to the mixture and disperse for 30min until the system is homogeneous and stable to obtain the main component Ca1 of the high thermal conductivity thermo-reversible color-changing coating.

[0047] (4) Disperse and mix 85 parts of isophorone diisocyanate and 15 parts of acetone using a high-speed disperser for 15 minutes until the system is homogeneous and stable to obtain the high thermal conductivity thermotropic reversible color-changing coating curing agent component Cb1.

[0048] (5) The preparation process of the main component Aa2 and the curing agent component Ab2 of the high reflectivity heat insulation coating is as described in Example 1.

[0049] (6) Weigh Aa2 main agent and Ab2 curing agent at a mass ratio of 1:0.13, mix them evenly with mechanical stirring, and then prepare a high-reflectivity heat insulation layer with a dry film thickness of 100μm by spraying.

[0050] (7) Weigh Ca1 main agent and Cb1 curing agent according to a mass ratio of 1:0.12, mix them evenly with mechanical stirring, and then prepare a high thermal conductivity thermo-reversible color-changing layer with a dry film thickness of 40μm by spraying after the high reflective heat insulation layer is dried. This will give you a double-layer thermo-reversible color-changing temperature control coating C.

[0051] Example 4: A thermotropic reversible color-changing temperature-controlled coating D based on hair structure microcapsules, the preparation process of which is as follows:

[0052] (1) Under heating conditions, 2.2 parts of 3',6'-dimethoxyfluorane, 3.5 parts of bisphenol S and 94.3 parts of tetradecyl alcohol were completely dissolved to prepare a clear ternary color-changing system oil phase. The oil phase was added to water containing 0.9% sodium dodecylbenzenesulfonate at 65°C to prepare a thermo-reversible color-changing emulsion. Then, 11 parts of melamine resin prepolymer were added dropwise to the emulsion under heating conditions and polymerized in situ at 85°C for 1 hour. The suspension after reaction was filtered and dried to obtain thermo-reversible color-changing microcapsules d1.

[0053] (2) 1.5 parts of N,N-methylenebisacrylamide, 4.5 parts of ethanol, 295 parts of toluene, 0.25 parts of trithiocarbonate and 0.035 parts of azobisisobutyronitrile were mixed evenly under ultrasonic conditions and completely dissolved at 80°C. 20 parts of thermochromic microcapsules d1 and 10 parts of nano silica particles were added to the mixture and dispersed evenly by high-speed stirring. After in-situ RAFT precipitation polymerization was carried out in a nitrogen environment at 80°C for 24 hours, the mixture was filtered and dried to obtain the mixed filler d of reversible color-changing microcapsules and nano silica with nano hair structure on the surface.

[0054] (3) Weigh 60 parts of waterborne fluorocarbon resin, 5.6 parts of water, 30 parts of mixed filler c, 0.6 parts of dispersant, 0.6 parts of leveling agent and 1 part of polymer wax. Use a high-speed disperser to disperse and mix the waterborne fluorocarbon resin and mixed filler d at 40~60℃ and a linear velocity of 6-10m / s for 15min. Then, perform ultrasonic treatment for 4~10min. Add the remaining components to the mixture and disperse for 30min until the system is homogeneous and stable to obtain the main component Da1 of the high thermal conductivity thermo-reversible color-changing coating.

[0055] (4) Hydrophilic HDI polyisocyanate was used as component Db1 of the curing agent for the high thermal conductivity thermo-reversible color-changing coating.

[0056] (5) The preparation process of the main component Aa2 and the curing agent component Ab2 of the high reflectivity heat insulation coating is as described in Example 1.

[0057] (6) Weigh Aa2 main agent and Ab2 curing agent at a mass ratio of 1:0.13, mix them evenly with mechanical stirring, and then prepare a high-reflectivity heat insulation layer with a dry film thickness of 100μm by spraying.

[0058] (7) Weigh Da1 main agent and Db1 curing agent according to a mass ratio of 1:0.15, mix them evenly with mechanical stirring, and then prepare a high thermal conductivity thermo-reversible color-changing layer with a dry film thickness of 40μm by spraying after the high reflective heat insulation layer is dried. This will give you a double-layer thermo-reversible color-changing temperature control coating D.

[0059] Example 5: A thermotropic reversible color-changing temperature-controlled coating E based on hair structure microcapsules, the preparation process of which is as follows:

[0060] (1) Under heating conditions, 4 parts of 2-phenylamino-3-methyl-6-dibutylaminofluorane, 8 parts of bisphenol A and 88 parts of methyl octadecyl ester were completely dissolved to prepare a clear ternary color-changing system oil phase. The oil phase was added to water containing 0.7% sodium salt of styrene-maleic anhydride copolymer at 65°C to prepare a thermo-reversible color-changing emulsion. Then, 10 parts of methyl melamine formaldehyde resin prepolymer were added dropwise to the emulsion under heating conditions and polymerized in situ at 85°C for 1 hour. The suspension after reaction was filtered and dried to obtain thermo-reversible color-changing microcapsules e1.

[0061] (2) 1.5 parts of N,N-methylenebisacrylamide, 4.5 parts of ethanol, 295 parts of toluene, 0.25 parts of trithiocarbonate and 0.035 parts of azobisisobutyronitrile were mixed evenly under ultrasonic conditions and completely dissolved at 80°C. 20 parts of thermochromic microcapsules e1 and 11 parts of nano silica particles were added to the mixture and dispersed evenly by high-speed stirring. After in-situ RAFT precipitation polymerization was carried out in a nitrogen environment at 80°C for 24 hours, the mixture was filtered and dried to obtain the mixed filler e of reversible color-changing microcapsules and nano silica with nano hair structure on the surface.

[0062] (3) Weigh 58 parts of silicone resin, 9 parts of butyl acetate, 27 parts of mixed filler e, 0.6 parts of leveling agent and 0.6 parts of defoamer. Use a high-speed disperser to disperse and mix the silicone resin and mixed filler e at 40~60℃ and a linear velocity of 6-10m / s for 15min. Then, perform ultrasonic treatment for 4~10min. Add the remaining components to the mixture and disperse for 30min until the system is uniform and stable to obtain the main component Ea1 of the high thermal conductivity thermo-reversible color-changing coating.

[0063] (4) Disperse and mix 60 parts of dicyclohexylmethane diisocyanate, 35 parts of hexamethylene diisocyanate biuret and 5 parts of butyl acetate using a high-speed disperser for 15 minutes until the system is homogeneous and stable to obtain the high thermal conductivity thermotropic reversible color-changing coating curing agent component Eb1.

[0064] (5) The preparation process of the main component Aa2 and the curing agent component Ab2 of the high reflectivity heat insulation coating is as described in Example 1.

[0065] (6) Weigh Aa2 main agent and Ab2 curing agent at a mass ratio of 1:0.13, mix them evenly with mechanical stirring, and then prepare a high-reflectivity heat insulation layer with a dry film thickness of 100μm by spraying.

[0066] (7) Weigh Ea1 main agent and Eb1 curing agent according to a mass ratio of 1:0.09, mix them evenly with mechanical stirring, and then prepare a high thermal conductivity thermo-reversible color-changing layer with a dry film thickness of 40μm by spraying after the high reflective heat insulation layer is dried. This will give you a double-layer thermo-reversible color-changing temperature control coating E.

[0067] Example 6: A thermotropic reversible color-changing temperature-controlled coating F based on hair structure microcapsules, the preparation process of which is as follows:

[0068] (1) Under heating conditions, 5.4 parts crystal violet lactone, 10 parts bisphenol F and 84.6 parts glyceryl tridecanoate were completely dissolved to prepare a clear ternary color-changing system oil phase. The oil phase was added to water containing 0.8% sodium dodecylbenzenesulfonate at 65°C to prepare a thermo-reversible color-changing emulsion. Then, 7.5 parts phenolic resin prepolymer were added dropwise to the emulsion under heating conditions and polymerized in situ at 85°C for 1 hour. The suspension after reaction was filtered and dried to obtain thermo-reversible color-changing microcapsules f1.

[0069] (2) 1.5 parts of N,N-methylenebisacrylamide, 4.5 parts of ethanol, 295 parts of toluene, 0.25 parts of trithiocarbonate and 0.035 parts of azobisisobutyronitrile were mixed evenly under ultrasonic conditions and completely dissolved at 80°C. 20 parts of thermochromic microcapsules f1 and 10 parts of nano silica particles were added to the mixture and dispersed evenly by high-speed stirring. After in-situ RAFT precipitation polymerization was carried out in a nitrogen environment at 80°C for 24 hours, the mixture was filtered and dried to obtain the mixed filler f of reversible color-changing microcapsules and nano silica with nano hair structure on the surface.

[0070] (3) Weigh 63 parts of polyurethane resin, 3.2 parts of propylene glycol methyl ether acetate, 25 parts of mixed filler f, 1 part of leveling agent and 1 part of adhesion promoter. Use a high-speed disperser to disperse and mix the polyurethane resin and mixed filler f at 40~60℃ and a linear velocity of 6-10m / s for 15min. Then, perform ultrasonic treatment for 4~10min. Add the remaining components to the mixture and disperse for 30min until the system is homogeneous and stable to obtain the main component Fa1 of the high thermal conductivity thermo-reversible color-changing coating.

[0071] (4) Disperse and mix 93 parts of cyclohexanedimethyl diisocyanate and 7 parts of propylene glycol methyl ether acetate using a high-speed disperser for 15 minutes until the system is homogeneous and stable to obtain the high thermal conductivity thermotropic reversible color-changing coating curing agent component Fb1.

[0072] (5) The preparation process of the main component Aa2 and the curing agent component Ab2 of the high reflectivity heat insulation coating is as described in Example 1.

[0073] (6) Weigh Aa2 main agent and Ab2 curing agent at a mass ratio of 1:0.13, mix them evenly with mechanical stirring, and then prepare a high-reflectivity heat insulation layer with a dry film thickness of 100μm by spraying.

[0074] (7) Weigh Fa1 main agent and Fb1 curing agent according to a mass ratio of 1:0.09, mix them evenly with mechanical stirring, and then prepare a high thermal conductivity thermo-reversible color-changing layer with a dry film thickness of 40μm by spraying after the high reflective heat insulation layer is dried. This will give you a double-layer thermo-reversible color-changing temperature control coating F.

[0075] Comparative Example 1: Commercially available thermochromic pigments

[0076] A thermochromic coating was prepared using a commercially available brand of thermochromic paint and its performance was compared with that of the examples.

[0077] Comparative Example 2: The coating was prepared using conventional thermochromic microcapsules, and the preparation process is as follows:

[0078] (1) Under heating conditions, 3.2 parts of crystal violet lactone, 8 parts of bisphenol F and 88.8 parts of methyl stearate were completely dissolved to prepare a clear ternary color-changing system oil phase. The oil phase was added to water containing 0.75% sodium dodecyl sulfate at 65°C to prepare a thermo-reversible color-changing emulsion. Then, 8.4 parts of methyl melamine formaldehyde resin prepolymer were added dropwise to the emulsion under heating conditions and polymerized in situ at 85°C for 1 hour. The suspension after reaction was filtered and dried to obtain thermo-reversible color-changing microcapsules c1.

[0079] (2) Weigh 55 parts of fluorocarbon resin, 8.5 parts of acetone, 20 parts of thermochromic microcapsules c1, 1 part of dispersant, 1 part of leveling agent, 1 part of defoamer and 1.3 parts of bentonite. Disperse and mix the fluorocarbon resin and thermochromic microcapsules c1 using a high-speed disperser at 40~60℃ and a linear velocity of 6-10m / s for 15min. Then, perform ultrasonic treatment for 4~10min. Add the remaining components to the mixture and disperse for 30min to obtain the main component Ga1 of the thermochromic coating.

[0080] (3) Disperse and mix 85 parts of isophorone diisocyanate and 15 parts of acetone using a high-speed disperser for 15 minutes until the system is homogeneous and stable to obtain the high thermal conductivity thermotropic reversible color-changing coating curing agent component Gb1.

[0081] (4) The preparation process of the main component Aa2 and the curing agent component Ab2 of the high reflectivity heat insulation coating is as described in Example 1.

[0082] (5) Weigh Aa2 main agent and Ab2 curing agent according to a mass ratio of 1:0.13, mix them evenly with mechanical stirring, and then prepare a high reflective heat insulation layer with a dry film thickness of 100μm by spraying.

[0083] (6) Weigh Ga1 main agent and Gb1 curing agent according to a mass ratio of 1:0.12, mix them evenly by mechanical stirring, and then prepare a thermochromic reversible color-changing layer with a dry film thickness of 40μm by spraying after the high reflective heat insulation layer is dried. This will give you a thermochromic reversible color-changing coating G with a double-layer structure prepared by conventional thermochromic microcapsules.

[0084] Comparative Example 3: A coating was prepared by combining conventional thermochromic microcapsules with nano-silica. The preparation process is as follows:

[0085] (1) Under heating conditions, 3.2 parts of crystal violet lactone, 8 parts of bisphenol F and 88.8 parts of methyl stearate were completely dissolved to prepare a clear ternary color-changing system oil phase. The oil phase was added to water containing 0.75% sodium dodecyl sulfate at 65°C to prepare a thermo-reversible color-changing emulsion. Then, 8.4 parts of methyl melamine formaldehyde resin prepolymer were added dropwise to the emulsion under heating conditions and polymerized in situ at 85°C for 1 hour. The suspension after reaction was filtered and dried to obtain thermo-reversible color-changing microcapsules c1.

[0086] (2) Weigh 55 parts of fluorocarbon resin, 8.5 parts of acetone, 20 parts of thermochromic microcapsule C1, 9 parts of nano silica particles, 1 part of dispersant, 1 part of leveling agent, 1 part of defoamer and 1.3 parts of bentonite. Disperse and mix the fluorocarbon resin, thermochromic microcapsule C1 and nano silica particles using a high-speed disperser at 40~60℃ and a linear velocity of 6-10m / s for 15min. Then, perform ultrasonic treatment for 4~10min. Add the remaining components to the mixture and disperse for 30min to obtain the main component Ha1 of the thermochromic coating.

[0087] (3) Disperse and mix 85 parts of isophorone diisocyanate and 15 parts of acetone using a high-speed disperser for 15 minutes until the system is homogeneous and stable to obtain Hb1, a curing agent component for high thermal conductivity thermo-reversible color-changing coating.

[0088] (4) The preparation process of the main component Aa2 and the curing agent component Ab2 of the high reflectivity heat insulation coating is as described in Example 1.

[0089] (5) Weigh Aa2 main agent and Ab2 curing agent according to a mass ratio of 1:0.13, mix them evenly with mechanical stirring, and then prepare a high reflective heat insulation layer with a dry film thickness of 100μm by spraying.

[0090] (6) Weigh Ha1 main agent and Hb1 curing agent according to a mass ratio of 1:0.12, mix them evenly with mechanical stirring, and then prepare a thermochromic reversible color-changing layer with a dry film thickness of 40μm by spraying after the high reflective heat insulation layer is dried. This will give you a thermochromic reversible color-changing coating H with a double-layer structure prepared using only conventional thermochromic microcapsules.

[0091] Comparative Example 4: The coating was prepared using only hair thermochromic microcapsules, and the preparation process is as follows:

[0092] (1) Under heating conditions, 2.2 parts of 3',6'-dimethoxyfluorane, 3.5 parts of bisphenol S and 94.3 parts of tetradecyl alcohol were completely dissolved to prepare a clear ternary color-changing system oil phase. The oil phase was added to water containing 0.9% sodium dodecylbenzenesulfonate at 65°C to prepare a thermo-reversible color-changing emulsion. Then, 11 parts of melamine resin prepolymer were added dropwise to the emulsion under heating conditions and polymerized in situ at 85°C for 1 hour. The suspension after reaction was filtered and dried to obtain thermo-reversible color-changing microcapsules d1.

[0093] (2) 1.5 parts of N,N-methylenebisacrylamide, 4.5 parts of ethanol, 295 parts of toluene, 0.25 parts of trithiocarbonate and 0.035 parts of azobisisobutyronitrile were mixed evenly under ultrasonic conditions and completely dissolved at 80°C. 20 parts of thermochromic microcapsules d1 were added to the mixture and dispersed evenly by high-speed stirring. After in-situ RAFT precipitation polymerization was carried out in a nitrogen environment at 80°C for 24 hours, the mixture was filtered and dried to obtain reversible color-changing microcapsules i with nano-hair structures on the surface.

[0094] (3) Weigh 60 parts of waterborne fluorocarbon resin, 5.6 parts of water, 20 parts of reversible color-changing microcapsules i, 0.6 parts of dispersant, 0.6 parts of leveling agent and 1 part of polymer wax. Use a high-speed disperser to disperse and mix the waterborne fluorocarbon resin and reversible color-changing microcapsules i at 40~60℃ and a linear velocity of 6-10m / s for 15min. Then, perform ultrasonic treatment for 4~10min. Add the remaining components to the mixture and disperse for 30min until the system is homogeneous and stable to obtain the main component Ia1 of the high thermal conductivity thermo-induced reversible color-changing coating.

[0095] (4) Hydrophilic HDI polyisocyanate was used as component Ib1 of the curing agent for the high thermal conductivity thermo-reversible color-changing coating.

[0096] (5) The preparation process of the main component Aa2 and the curing agent component Ab2 of the high reflectivity heat insulation coating is as described in Example 1.

[0097] (6) Weigh Aa2 main agent and Ab2 curing agent at a mass ratio of 1:0.13, mix them evenly with mechanical stirring, and then prepare a high-reflectivity heat insulation layer with a dry film thickness of 100μm by spraying.

[0098] (7) Weigh Ia1 main agent and Ib1 curing agent according to a mass ratio of 1:0.15, mix them evenly with mechanical stirring, and then prepare a thermo-reversible color-changing layer with a dry film thickness of 40μm by spraying after the high reflective heat insulation layer is dried. This will give you a double-layer thermo-reversible color-changing coating I prepared by using only hair thermo-reversible color-changing microcapsules.

[0099] Comparative Example 5: A single-layer thermotropic reversible color-changing temperature-controlled coating, the preparation process of which is as follows:

[0100] (1) The preparation process of the main component Fa1 and the curing agent component Fb1 of the high thermal conductivity thermo-reversible color-changing coating is as described in Example 6.

[0101] (2) The preparation process of the main component Aa2 and the curing agent component Ab2 of the high reflectivity heat insulation coating is as described in Example 1.

[0102] (3) Weigh Fa1 main agent and Aa2 main agent at a mass ratio of 40:100 and mix them evenly to obtain thermochromic reversible color-changing coating main agent Ja. Weigh Fb1 curing agent and Ab2 curing agent at a mass ratio of 3.6:13 and mix them evenly to obtain thermochromic reversible color-changing coating main agent Jb.

[0103] (4) Weigh Ja main agent and Jb curing agent according to the mass ratio of 140:16.6, mix them evenly with mechanical stirring, and then prepare a high-reflectivity heat-insulating color-changing coating with a dry film thickness of 140μm by spraying.

[0104] Comparative Example 6: A thermotropic reversible color-changing temperature-controlled coating was prepared with a high nano-silica content. The preparation process is as follows:

[0105] (1) Under heating conditions, 4 parts of 2-phenylamino-3-methyl-6-dibutylaminofluorane, 8 parts of bisphenol A and 88 parts of methyl octadecyl ester were completely dissolved to prepare a clear ternary color-changing system oil phase. The oil phase was added to water containing 0.7% sodium salt of styrene-maleic anhydride copolymer at 65°C to prepare a thermo-reversible color-changing emulsion. Then, 10 parts of methyl melamine formaldehyde resin prepolymer were added dropwise to the emulsion under heating conditions and polymerized in situ at 85°C for 1 hour. The suspension after reaction was filtered and dried to obtain thermo-reversible color-changing microcapsules e1.

[0106] (2) 1.5 parts of N,N-methylenebisacrylamide, 4.5 parts of ethanol, 295 parts of toluene, 0.25 parts of trithiocarbonate and 0.035 parts of azobisisobutyronitrile were mixed evenly under ultrasonic conditions and completely dissolved at 80°C. 15 parts of thermochromic microcapsules e1 and 15 parts of nano silica particles were added to the mixture and dispersed evenly by high-speed stirring. After in-situ RAFT precipitation polymerization was carried out in a nitrogen environment at 80°C for 24 hours, the mixture was filtered and dried to obtain the mixed filler K of reversible color-changing microcapsules and nano silica with nano hair structure on the surface.

[0107] (3) Weigh 58 parts of silicone resin, 9 parts of butyl acetate, 27 parts of mixed filler K, 0.6 parts of leveling agent and 0.6 parts of defoamer. Use a high-speed disperser to disperse and mix the silicone resin and mixed filler e at 40~60℃ and a linear velocity of 6-10m / s for 15min. Then, perform ultrasonic treatment for 4~10min. Add the remaining components to the mixture and disperse for 30min until the system is uniform and stable to obtain the main component Ka1 of the high thermal conductivity thermo-reversible color-changing coating.

[0108] (4) Disperse and mix 60 parts of dicyclohexylmethane diisocyanate, 35 parts of hexamethylene diisocyanate biuret and 5 parts of butyl acetate using a high-speed disperser for 15 minutes until the system is homogeneous and stable to obtain Kb1, a curing agent component for high thermal conductivity thermo-reversible color-changing coating.

[0109] (5) The preparation process of the main component Aa2 and the curing agent component Ab2 of the high reflectivity heat insulation coating is as described in Example 1.

[0110] (6) Weigh Aa2 main agent and Ab2 curing agent at a mass ratio of 1:0.13, mix them evenly with mechanical stirring, and then prepare a high-reflectivity heat insulation layer with a dry film thickness of 100μm by spraying.

[0111] (7) Weigh Ka1 main agent and Kb1 curing agent according to a mass ratio of 1:0.09, mix them evenly with mechanical stirring, and then prepare a thermo-reversible color-changing layer with a dry film thickness of 40μm by spraying after the high reflective heat insulation layer has dried. This will give you a double-layer structure coating K.

[0112] The thermotropic reversible color-changing temperature-controlled coatings based on hair structure microcapsules prepared in Examples 1-6 of this invention were compared with the comparative coatings in Examples 1-6. The apparent brightness, solar reflectance, surface transverse thermal conductivity, color-changing distribution, and cycling stability of the coatings at different temperatures were tested, and the relevant test results are summarized in Table 1.

[0113] Table 1 Performance test results of color-changing temperature-controlled coating

[0114]

[0115] As can be seen from the data in Table 1, the thermotropic reversible color-changing temperature-controlled coating based on hair-structured microcapsules prepared in the examples exhibits significant differences in brightness and solar reflectance under low and high temperature conditions, with a more pronounced change in temperature control capability. Furthermore, it demonstrates faster lateral thermal conduction and more uniform overall color change, resulting in better performance under wide-ranging application conditions and a superior visual appearance. This is attributed to the synergistic effect of the hair-structured microcapsules and the uniformly distributed nano-silica within them. Moreover, the system shows no significant degradation in color-changing performance after 300 color-changing cycles, indicating better long-term service performance. These experimental results confirm the strong practical value of the embodiments of the present invention.

[0116] Comparative Example 1 is a commercially available thermochromic coating. The results show that the thermochromic coating has a relatively weak color-changing ability. Moreover, since it does not contain a high-reflectivity heat-insulating filler component, its reflectivity is very poor. Even under conditions with a high brightness value, the reflectivity is still relatively low. Therefore, it does not have the ability to control temperature through reflection. Furthermore, the thermochromic component in it has poor stability. After 300 color-changing cycles, its color-changing performance has significantly decreased.

[0117] Comparative Example 2 shows a double-layer thermochromic coating prepared using only conventional thermochromic microcapsules. It can be seen that the conventional microcapsules have poor dispersion properties, and their color-changing ability and temperature control are inferior to those of the previous examples. Furthermore, because they do not contain thermally conductive fillers, their surface thermal conductivity is low, resulting in poor color uniformity during the color-changing process. Comparative Example 3, although incorporating nano-silica as a thermally conductive filler, suffers from limited uniformity of distribution and relatively weak thermal bridging effect due to the lack of hair-like bonding structures, thus limiting its enhancement of thermal conductivity and resulting in a relatively weak effect.

[0118] Comparative Example 4 shows a bilayer thermochromic coating prepared using only hair-structured color-changing microcapsules. It exhibits relatively good dispersion performance, but also suffers from poor thermal conductivity due to the absence of heat-enhancing fillers, resulting in weak color uniformity. Comparative Example 5 shows a thermochromic coating prepared by mixing a high-reflectivity heat-insulating layer and a high-thermal-conductivity thermochromic layer into a single-layer structure. The results indicate that the low concentration of microcapsules and the strong tinting strength of rutile titanium dioxide significantly affect its color-changing performance, making intelligent temperature control difficult to achieve. Furthermore, the effect of enhancing thermal conductivity is significantly diluted, highlighting the importance of layered preparation. Example 6 shows a bilayer thermochromic coating prepared using a larger amount of nano-silica particles. It is evident that the increased nano-silica and decreased color-changing microcapsules significantly reduce its color-changing ability. Additionally, the relatively fewer hair channels and the reduced thermal conductivity enhancement effect are also negatively impacted.

[0119] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments without departing from the technical essence of the present invention shall still fall within the scope of the present invention.

Claims

1. A thermotropic reversible color-changing temperature-controlled coating based on hair structure microcapsules, characterized in that... It is a temperature-controlled coating with a dual-layer structure consisting of a high-reflectivity heat insulation layer and a high-thermal-conductivity thermochromic layer; The high-reflectivity heat insulation layer is prepared from a high-performance reflective heat insulation coating using rutile titanium dioxide and hollow glass microspheres as fillers; the high-thermal-conductivity thermochromic layer is prepared from a high-thermal-conductivity thermochromic coating using thermochromic microcapsules with hair-like surface structures and nano-silica as fillers; the dry film thicknesses of the high-reflectivity heat insulation layer and the high-thermal-conductivity thermochromic layer are 80-120 μm and 30-50 μm, respectively; the preparation method of the filler in the high-thermal-conductivity thermochromic coating includes the following steps: (1) The ternary thermochromic reversible color-changing core material composed of pigment, color developer and solvent is dissolved and added to water containing emulsifier. After high-speed emulsification under heating conditions of 65°C, a thermochromic reversible color-changing emulsion is obtained; (2) Under heating and stirring conditions, the resin prepolymer is added dropwise to the reversible color-changing emulsion at a constant rate. After the addition is completed, in-situ polymerization is carried out at 85°C for 1 hour. The suspension after reaction is filtered and dried to obtain thermochromic reversible color-changing microcapsules; (3) N,N-methylenebisacrylamide, ethanol, toluene, RAFT reagent and initiator are mixed and dissolved completely. The reversible color-changing microcapsules and nano silica are added to it and dispersed evenly by high-speed stirring. In-situ RAFT precipitation polymerization is carried out in a nitrogen environment of 80°C for 24 hours. After filtration and drying, a reversible color-changing microcapsule and nano silica mixed filler with nano hair structure on the surface is obtained; The mass ratio of hair-structured thermotropic color-changing microcapsules and nano-silica in the filler of the high thermal conductivity thermotropic reversible color-changing coating is 1:(0.3~0.6).

2. The thermotropic reversible color-changing temperature-controlled coating based on hair structure microcapsules as described in claim 1, characterized in that... The high thermal conductivity thermotropic reversible color-changing coating is composed of component A1 (main agent) and component B1 (curing agent). Component A1 is prepared from a matrix resin, hair-structured microcapsules, nano-silica composite filler, solvent, functional additives, and rheology modifier. Component B1 is prepared from a curing agent and a solvent. The mass ratio of component A1 to component B1 is 1:(0.08~0.22). The high-performance reflective heat-insulating coating is composed of component A2 (main agent) and component B2 (curing agent). Component A2 is prepared from a matrix resin, rutile titanium dioxide, hollow glass microspheres, solvent, functional additives, and rheology modifier. The mass ratio of rutile titanium dioxide to hollow glass microspheres is 1:(0.8~1.2). Component B2 is prepared from a curing agent and a solvent. The mass ratio of component A2 to component B2 is 1:(0.08~0.22).

3. The thermotropic reversible color-changing temperature-controlled coating based on hair structure microcapsules as described in claim 1, characterized in that... The pigment is at least one of crystal violet lactone, 2-phenylamino-3-methyl-6-dibutylaminofluorane, and 3',6'-dimethoxyfluorane; the color developer is at least one of bisphenol A, bisphenol F, and bisphenol S; the solvent contains at least one of tetradecyl alcohol, glyceryl tridecanoate, methyl octadecanoate, and ethyl octadecanoate; wherein the mass concentration of the pigment molecules is 0.8-6%, and the mass ratio of pigment to color developer is 1:(1.5-4) based on the mass of the ternary color-changing core material; wherein the emulsifier is at least one of sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, and sodium salt of styrene-maleic anhydride copolymer, with a mass concentration of 0.5-1%; wherein the resin prepolymer is at least one of melamine resin prepolymer, urea-formaldehyde resin prepolymer, methyl melamine-formaldehyde resin prepolymer, polyurethane resin prepolymer, and acrylic resin, and the amount used is 5-13% of the total amount.

4. The thermotropic reversible color-changing temperature-controlled coating based on hair structure microcapsules as described in claim 1, characterized in that... The N,N-methylenebisacrylamide has a mass concentration of 0.5-1.5%, the ethanol has a mass concentration of 1.5-3%, and the RAFT reagent is at least one of dithiobenzoate, trithiocarbonate, and dithiocarbamate, with an amount of 8-12% of the monomer; the initiator is at least one of azobisisobutyronitrile, azobisisoheptanenitrile, benzoyl peroxide, and lauroyl peroxide, with an amount of 1-2% of the monomer.

5. The thermotropic reversible color-changing temperature-controlled coating based on hair structure microcapsules according to claim 2, characterized in that... In the main components of the two coatings, the contents of the matrix resin, filler, solvent, functional additives, and rheology modifier are 50-72%, 22-33%, 3-10%, 0.5-3.5%, and 0.5-2.0%, respectively, based on the total mass of the main components; wherein the matrix resin is at least one of silicone resin, fluorocarbon resin, polyurethane resin, and acrylic-modified polyurethane resin; wherein the solvent is at least one of xylene, acetone, n-butanol, butyl acetate, dimethylformamide, propylene glycol methyl ether acetate, and water; wherein the functional additive is at least one of dispersant, defoamer, leveling agent, and adhesion promoter; wherein the rheology modifier is at least one of bentonite, hydrated magnesium silicate, fumed silica, and polymer wax.

6. The thermotropic reversible color-changing temperature-controlled coating based on hair structure microcapsules as described in claim 2, characterized in that... In the curing agent of component B of the two coatings, the content of isocyanate and solvent is 85%-100% and 0-15% respectively, based on the total mass of component B; wherein the isocyanate is at least one selected from toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, cyclohexane diisocyanate, phenyl diisocyanate, hydrophilic HDI polyisocyanate, polymethylene polyphenyl polyisocyanate, hexamethylene diisocyanate trimer, and hexamethylene diisocyanate biuret; the solvent is at least one selected from xylene, methyl ethyl ketone, ethanol, n-butanol, butyl acetate, dimethylformamide, propylene glycol methyl ether acetate, and water.

7. The thermotropic reversible color-changing temperature-controlled coating based on hair structure microcapsules as described in claim 2, characterized in that... The preparation methods of the two coatings mentioned above include the following steps: (1) Weigh out appropriate amounts of each component, disperse and mix the matrix resin and filler using a high-speed disperser at 40~60℃ and a linear velocity of 6-10m / s for 15min, then perform ultrasonic treatment for 4~10min, and then add the remaining components to the mixture and disperse for 30min until the system is homogeneous and stable to obtain the coating main component; (2) Disperse and mix the isocyanate and solvent using a high-speed disperser for 15min until the system is homogeneous and stable to obtain the curing agent component.

8. The thermotropic reversible color-changing temperature-controlled coating based on hair structure microcapsules as described in claim 1, characterized in that... The on-site application method for the two coatings mentioned above can be any one of spraying, dipping, rolling, and brushing.

9. The application of the thermotropic reversible color-changing temperature-controlling coating based on hair structure microcapsules as described in claim 1 as a surface temperature-controlling material for buildings, cold storage facilities, industrial storage tanks, and transportation infrastructure structures.

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