Infrared reflection composite heat insulation coating and preparation method thereof

Abstract

The invention relates to the technical field of coatings, and discloses an infrared reflection composite heat insulation coating and a preparation method thereof. Comprising the following raw materials in parts by weight: 10-20 parts of a pure acrylic emulsion, 10-20 parts of a silicone acrylic emulsion, 5-10 parts of a modified styrene-acrylic emulsion, 0.3-1 part of a dispersing agent, 0.1-0.5 part of a defoaming agent, 0.1-0.5 part of a wetting agent, 1-3 parts of a thickening agent, 0.1-0.5 part of a coalescing agent, 3-8 parts of titanium dioxide, 5-10 parts of modified hollow glass beads and 2 parts of far infrared ceramic powder. According to the invention, the modified styrene-acrylic emulsion is prepared, and the heat-insulating property, the mechanical property, the flame-retardant property and the antibacterial property of the coating are synergistically improved by utilizing the diene-containing gemini quaternary ammonium salt contained in the modified styrene-acrylic emulsion and the modified hollow glass beads.

Description

Technical Field

[0001] This invention relates to the field of coating technology, specifically to an infrared reflective composite heat-insulating coating and its preparation method. Background Technology

[0002] With the continuous development of the economy and the gradual improvement of people's living standards, the global energy demand is increasing year by year. Energy conservation and emission reduction have become the only way for the sustainable development of society. Among them, building energy conservation is an important measure for energy conservation and emission reduction. The use of heat insulation coatings to solve the problem of increased surface temperature of building exterior walls caused by solar radiation and reduce the impact of solar radiation has also become a hot topic in building energy conservation.

[0003] However, building exterior walls are exposed to humid environments and temperature fluctuations for extended periods, making them prone to the growth of microorganisms such as algae, mold, and fungi. The mycelium of these microorganisms may penetrate the coating, damaging the integrity of the paint film. Furthermore, the microbial community and its secretions may form a biofilm on the coating surface, altering its optical properties (such as reflectivity) and thermal resistance characteristics. This, in turn, affects the solar reflectivity and radiative heat dissipation efficiency of the thermal insulation coating. Therefore, keeping the surface clean helps ensure the long-term stable performance of the thermal insulation material.

[0004] For example, patent application publication number CN 120623841 A discloses a high-performance environmentally friendly coating for building exterior walls and its preparation method. The coating prepared by the patent using hollow glass microspheres, styrene-acrylic emulsion and other raw materials has excellent heat insulation performance, impact resistance and antibacterial performance, but does not improve the flame retardant performance of the coating. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] To address the shortcomings of existing technologies, this invention provides an infrared reflective composite heat-insulating coating and its preparation method. The prepared coating exhibits excellent heat insulation performance, mechanical properties, flame retardant properties, and antibacterial properties.

[0007] (II) Technical Solution

[0008] An infrared reflective composite heat-insulating coating, characterized in that the coating comprises the following raw materials in parts by weight: 10-20 parts by weight of pure acrylic emulsion, 10-20 parts by weight of silicone acrylic emulsion, 5-10 parts by weight of modified styrene-acrylic emulsion, 0.3-1 parts by weight of dispersant, 0.1-0.5 parts by weight of defoamer, 0.1-0.5 parts by weight of wetting agent, 1-3 parts by weight of thickener, 0.1-0.5 parts by weight of film-forming aid, 3-8 parts by weight of titanium dioxide, 5-10 parts by weight of modified hollow glass microspheres, 2 parts by weight of far-infrared ceramic powder, and the balance being deionized water;

[0009] The preparation method of the infrared reflective composite heat insulation coating includes the following steps:

[0010] Step A1: Dissolve the emulsifier in deionized water, stir and disperse, introduce nitrogen gas, heat to 50-60℃, add initiator, styrene, methyl methacrylate, acrylic acid, and diene-containing quaternary ammonium salt to the above solution, stir and react for 3-5 hours. After the reaction is completed, cool down and discharge to obtain modified styrene-acrylic emulsion. In this process, the diene-containing quaternary ammonium salt contains a diene structure, which can copolymerize with other monoene structures to form a nonlinear emulsion containing a large number of chemically cross-linked network structures. Adding it to the coating can improve the mechanical properties of the coating.

[0011] Step A2: Add the dispersant, defoamer, and wetting agent to deionized water and stir to mix evenly. Then add titanium dioxide and far-infrared ceramic powder and stir to disperse. Add pure acrylic emulsion, silicone acrylic emulsion, modified styrene acrylic emulsion, and film-forming aid and stir for 5-10 minutes. Finally, add modified hollow glass microspheres and thickener and continue stirring for 5-10 minutes to obtain infrared reflective composite heat insulation coating.

[0012] Preferably, in step A1, the mass ratio of emulsifier, initiator, styrene, methyl methacrylate, acrylic acid, and diene-containing quaternary ammonium salt is 10-15:1-3:100:10-30:20-40:10-30.

[0013] Preferably, the method for preparing the modified hollow glass microspheres includes the following steps:

[0014] Clean hollow glass microspheres were added to ethanol and stirred slowly for 10-12 hours. The mixture was then filtered, dried, and added to a cerium nitrate aqueous solution. The mixture was ultrasonically dispersed, stirred slowly for 10-12 hours, filtered, and dried to obtain modified hollow glass microspheres. During this process, rare earth ions could enter the surface layer through defects in the hollow glass microspheres and remain at the defect sites. Due to the strong electronegativity and reactivity of rare earth ions, the rare earth ions remaining at the defect sites could become active centers, forming coordination bonds with the oxygen on the hydroxyl groups of the hollow glass microspheres to generate Ce-O bonds, thus attaching to the surface of the hollow glass microspheres. On the one hand, rare earth ions... The carboxylate ions and hydroxyl groups in the substrate form chemical bonds, which act as a "bridge," improving the adhesion between the substrate and the hollow glass microspheres at the interface and enhancing the dispersibility of the hollow glass microspheres in the coating, ensuring their uniform dispersion. On the other hand, cerium nitrate generates cerium oxide during combustion, which has flame-retardant properties. It is uniformly dispersed on the surface of the hollow glass microspheres, forming a dense and continuous protective carbon layer that protects the hollow glass microspheres from losing their activity at high temperatures, blocks heat transfer, delays the entry of fire heat into the building interior, and improves the flame-retardant and heat-insulating performance of the building coating.

[0015] Preferably, the concentration of the cerium nitrate aqueous solution is 1-2%.

[0016] Preferably, the preparation method of the diene-containing gemini quaternary ammonium salt includes the following steps:

[0017] Step A11: Dissolve 1,4-piperazine diethylamine in ethanol, add 4-formylphenylboronic acid, and stir the reaction at room temperature for 10-12 hours. After the reaction is complete, filter, wash with ethanol, and dry to obtain intermediate 1. The molar ratio of 1,4-piperazine diethylamine to 4-formylphenylboronic acid is 1:2-2.1. In this step, 1,4-piperazine diethylamine and 4-formylphenylboronic acid are used as raw materials, and intermediate 1 is obtained through Schiff base reaction. The synthetic route is as follows:

[0018] ;

[0019] Step A12: Add intermediate 1 to acetone solvent, then add allyl chloride, stir to disperse, and reflux for 8-10 hours. After the reaction is complete, filter, wash the precipitate with acetone, and recrystallize to obtain a diene-containing quaternary ammonium salt. The molar ratio of intermediate 1 to allyl chloride is 1:2.5-3. In this step, intermediate 1 and allyl chloride are used as raw materials, and a quaternization reaction is carried out to obtain a diene-containing quaternary ammonium salt. The reaction synthesis route is as follows:

[0020] .

[0021] (iii) Beneficial technical effects

[0022] The heat-insulating coating prepared by this invention contains titanium dioxide, far-infrared ceramic powder, and hollow glass microspheres. Titanium dioxide has high reflectivity and scattering rate for light. Far-infrared ceramic powder can radiate absorbed heat in the form of far-infrared rays of a specific wavelength. Hollow glass microspheres are hollow, micron-sized spherical powders. When the hollow glass microspheres are uniformly dispersed in the coating, the "hollow spheres" form a complex "honeycomb" or "labyrinthine" heat-insulating layer containing a large amount of still air inside the material. The path of heat transfer in the material is continuously interrupted and extended by these "hollow spheres," achieving the purpose of heat insulation. In addition, the coating prepared by this invention contains a twin antibacterial quaternary ammonium salt structure and a titanium dioxide inorganic antibacterial structure. The use of two antibacterial structures with different antibacterial mechanisms achieves a synergistic antibacterial effect, preventing the growth of algae, mold, fungi, and other microorganisms, which could penetrate the coating and damage the integrity of the paint film, thereby improving the durability and structural protection of the building.

[0023] The coating prepared by this invention exhibits excellent flame-retardant properties for the following reasons: This invention prepares a diene-containing quaternary ammonium salt through simple steps, containing boron and nitrogen elements. In the initial stage of combustion, the boron compound absorbs heat, decomposes upon heating, and releases water of crystallization, lowering the surface temperature of the material. The released boron oxides (such as B2O3) melt at high temperatures, forming a viscous, dense, glassy coating layer that firmly adheres to the polymer or material surface, effectively isolating external oxygen from contact with internal combustibles. Nitrogen elements, upon heating, generate inert gas, diluting the concentration of flammable gases in the air, achieving a synergistic flame-retardant effect. Furthermore, it also contains a Schiff base structure, which absorbs heat upon heating. The ring-opening cross-linking forms a dense cross-linked network structure. Upon further combustion, a dense char layer is formed. During combustion, cerium nitrate forms cerium oxide on the surface of the hollow glass microspheres. The nano-CeO2 particles are uniformly dispersed in the polymer matrix. They can slow down heat conduction and the diffusion of combustible gases. At the same time, they are very stable at high temperatures and work together with the formed char layer to form a strong physical flame-retardant barrier, thus achieving the purpose of flame retardancy. In other words, this invention improves the flame-retardant performance of the coating through a double-layer flame-retardant structure. Furthermore, the double-layer flame-retardant layer can also protect the hollow glass microspheres and titanium dioxide from deactivation at high temperatures, thereby maintaining their heat insulation effect and slowing down heat transfer. This has significant implications for the multifunctional development of building heat insulation coatings. Detailed Implementation

[0024] The invention will now be described in further detail with reference to examples.

[0025] Example 1

[0026] This embodiment provides an infrared reflective composite heat insulation coating, which comprises the following raw materials in parts by weight: 15 parts by weight of pure acrylic emulsion, 20 parts by weight of silicone acrylic emulsion, 5 parts by weight of modified styrene-acrylic emulsion, 1 part by weight of dispersant, 0.4 parts by weight of defoamer, 0.1 parts by weight of wetting agent, 3 parts by weight of thickener, 0.5 parts by weight of film-forming aid, 3 parts by weight of titanium dioxide, 5 parts by weight of modified hollow glass microspheres, 2 parts by weight of far-infrared ceramic powder, and the balance being deionized water, for a total of 100 parts by weight;

[0027] The preparation method of the infrared reflective composite heat insulation coating includes the following steps:

[0028] Step A1: Dissolve 15 parts by weight of emulsifier SDS in deionized water, stir and disperse, introduce nitrogen gas, heat to 50°C, add 3 parts by weight of initiator, 100 parts by weight of styrene, 10 parts by weight of methyl methacrylate, 40 parts by weight of acrylic acid, and 10 parts by weight of diene-containing quaternary ammonium salt to the above solution, stir and react for 3 hours, after the reaction is completed, cool down, discharge the material, and obtain modified styrene-acrylic emulsion;

[0029] Step A2: According to the above formula by weight, add dispersant BYK-194, defoamer BYK-094, and wetting agent BYK-346 to deionized water and stir to mix evenly. Then add titanium dioxide and far-infrared ceramic powder and stir to disperse. Add pure acrylic emulsion, silicone acrylic emulsion, modified styrene acrylic emulsion, and film-forming aid propylene glycol butyl ether and stir for 5 minutes. Finally, add modified hollow glass microspheres and thickener RM-8W and continue stirring for 10 minutes to obtain infrared reflective composite heat insulation coating.

[0030] The method for preparing the modified hollow glass microspheres includes the following steps:

[0031] 10g of clean hollow glass microspheres were added to ethanol and stirred slowly for 12h. After filtration and drying, the microspheres were added to a 1% cerium nitrate aqueous solution, ultrasonically dispersed, stirred slowly for 10h, filtered, and dried to obtain modified hollow glass microspheres.

[0032] The preparation method of the diene-containing gemini quaternary ammonium salt includes the following steps:

[0033] Step A11: Dissolve 80 mmol of 1,4-piperazine diethylamine in ethanol, add 165 mmol of 4-formylphenylboronic acid, stir the reaction at room temperature for 11 h, filter, wash with ethanol, and dry to obtain intermediate 1.

[0034] Step A12: Add 50 mmol of intermediate 1 to acetone solvent, then add 130 mmol of allyl chloride, stir to disperse, reflux for 8 h, filter, wash the precipitate with acetone, recrystallize to obtain diene-containing quaternary ammonium salt.

[0035] Example 2

[0036] This embodiment provides an infrared reflective composite heat insulation coating, which comprises the following raw materials in parts by weight: 10 parts by weight of pure acrylic emulsion, 20 parts by weight of silicone acrylic emulsion, 8 parts by weight of modified styrene-acrylic emulsion, 0.5 parts by weight of dispersant, 0.5 parts by weight of defoamer, 0.5 parts by weight of wetting agent, 2 parts by weight of thickener, 0.3 parts by weight of film-forming aid, 5 parts by weight of titanium dioxide, 8 parts by weight of modified hollow glass microspheres, 2 parts by weight of far-infrared ceramic powder, and the balance being deionized water, for a total of 100 parts by weight.

[0037] The preparation method of the infrared reflective composite heat insulation coating includes the following steps:

[0038] Step A1: Dissolve 12 parts by weight of emulsifier SDS in deionized water, stir and disperse, introduce nitrogen gas, heat to 60°C, add 2 parts by weight of initiator, 100 parts by weight of styrene, 20 parts by weight of methyl methacrylate, 20 parts by weight of acrylic acid, and 20 parts by weight of diene-containing quaternary ammonium salt to the above solution, stir and react for 4 hours, after the reaction is completed, cool down, discharge the material, and obtain modified styrene-acrylic emulsion;

[0039] Step A2: According to the above formula by weight, add dispersant BYK-194, defoamer BYK-094, and wetting agent BYK-346 to deionized water and stir to mix evenly. Then add titanium dioxide and far-infrared ceramic powder and stir to disperse. Add pure acrylic emulsion, silicone acrylic emulsion, modified styrene acrylic emulsion, and film-forming aid propylene glycol butyl ether and stir for 10 minutes. Finally, add modified hollow glass microspheres and thickener RM-8W and continue stirring for 8 minutes to obtain infrared reflective composite heat insulation coating.

[0040] The method for preparing the modified hollow glass microspheres includes the following steps:

[0041] 10g of clean hollow glass microspheres were added to ethanol and stirred slowly for 11h. After filtration and drying, the microspheres were added to a 2% cerium nitrate aqueous solution, ultrasonically dispersed, stirred slowly for 12h, filtered, and dried to obtain modified hollow glass microspheres.

[0042] The preparation method of the diene-containing gemini quaternary ammonium salt includes the following steps:

[0043] Step A11: Dissolve 80 mmol of 1,4-piperazine diethylamine in ethanol, add 168 mmol of 4-formylphenylboronic acid, stir the reaction at room temperature for 10 h, filter, wash with ethanol, and dry to obtain intermediate 1.

[0044] Step A12: Add 50 mmol of intermediate 1 to acetone solvent, then add 150 mmol of allyl chloride, stir to disperse, reflux for 10 h, filter, wash the precipitate with acetone, recrystallize to obtain the diene-containing quaternary ammonium salt.

[0045] Example 3

[0046] This embodiment provides an infrared reflective composite heat insulation coating, which comprises the following raw materials in parts by weight: 20 parts by weight of pure acrylic emulsion, 10 parts by weight of silicone acrylic emulsion, 10 parts by weight of modified styrene-acrylic emulsion, 1 part by weight of dispersant, 0.1 part by weight of defoamer, 0.4 parts by weight of wetting agent, 1 part by weight of thickener, 0.1 part by weight of film-forming aid, 8 parts by weight of titanium dioxide, 10 parts by weight of modified hollow glass microspheres, 2 parts by weight of far-infrared ceramic powder, and the balance being deionized water, for a total of 100 parts by weight;

[0047] The preparation method of the infrared reflective composite heat insulation coating includes the following steps:

[0048] Step A1: Dissolve 10 parts by weight of emulsifier TX-10 in deionized water, stir and disperse, introduce nitrogen gas, heat to 55°C, add 3 parts by weight of initiator, 100 parts by weight of styrene, 30 parts by weight of methyl methacrylate, 30 parts by weight of acrylic acid, and 30 parts by weight of diene-containing quaternary ammonium salt to the above solution, stir and react for 5 hours, after the reaction is completed, cool down and discharge to obtain modified styrene-acrylic emulsion;

[0049] Step A2: According to the above formula by weight, add dispersant BYK-194, defoamer BYK-094, and wetting agent BYK-346 to deionized water and stir to mix evenly. Then add titanium dioxide and far-infrared ceramic powder and stir to disperse. Add pure acrylic emulsion, silicone acrylic emulsion, modified styrene acrylic emulsion, and film-forming aid propylene glycol butyl ether and stir for 10 minutes. Finally, add modified hollow glass microspheres and thickener RM-8W and continue stirring for 10 minutes to obtain infrared reflective composite heat insulation coating.

[0050] The method for preparing the modified hollow glass microspheres includes the following steps:

[0051] 10g of clean hollow glass microspheres were added to ethanol and stirred slowly for 10h. After filtration and drying, the microspheres were added to a 2% cerium nitrate aqueous solution, ultrasonically dispersed, stirred slowly for 12h, filtered, and dried to obtain modified hollow glass microspheres.

[0052] The preparation method of the diene-containing gemini quaternary ammonium salt includes the following steps:

[0053] Step A11: Dissolve 80 mmol of 1,4-piperazine diethylamine in ethanol, add 160 mmol of 4-formylphenylboronic acid, stir the reaction at room temperature for 12 h, filter, wash with ethanol, and dry to obtain intermediate 1.

[0054] Step A12: Add 50 mmol of intermediate 1 to acetone solvent, then add 140 mmol of allyl chloride, stir to disperse, reflux for 9 h, filter, wash the precipitate with acetone, recrystallize to obtain the diene-containing quaternary ammonium salt.

[0055] Comparative Example 1

[0056] The difference between this comparative example and Example 1 is that step A2 does not contain modified hollow glass microspheres, while the remaining steps are the same as in Example 1.

[0057] Comparative Example 2

[0058] The difference between this comparative example and Example 1 is that in step A2, hollow glass microspheres are used instead of modified hollow glass microspheres, while the remaining steps are the same as in Example 1.

[0059] Comparative Example 3

[0060] The difference between this comparative example and Example 1 is that step A1 does not contain diene-containing gemini quaternary ammonium salts, while the remaining steps are the same as in Example 1.

[0061] Comparative Example 4

[0062] The difference between this comparative example and Example 1 is that in step A1, a commercially available quaternary ammonium salt antibacterial agent is used instead of a diene-containing quaternary ammonium salt, while the remaining steps are the same as in Example 1.

[0063] A film is quickly and evenly formed along the longitudinal direction on a glass plate using a film-forming device. After the coating is dried, the film is repeated twice and allowed to dry naturally for 48 hours to obtain the final coating.

[0064] According to GB / T9271-2008, the thermal insulation temperature difference of the coating was tested;

[0065] The vertical flammability rating of the coating was tested using a vertical burner.

[0066] Table 1:

[0067]

[0068] The coatings prepared in the embodiments of this invention all meet the national standards for building thermal insulation coatings, namely, a thermal insulation temperature difference > 10℃. Comparative Example 2, which uses hollow glass microspheres instead of modified hollow glass microspheres, has a lower thermal insulation effect than the embodiments. This is because the unmodified hollow glass microspheres have poor compatibility with the coating substrate, cannot be uniformly dispersed in the substrate, and agglomerate within the substrate, affecting the thermal insulation and overall performance of the coating. Comparative Example 3, which does not contain diene-containing quaternary ammonium salt in step A1, has a lower thermal insulation effect than Example 1. The reason for this is likely that the diene-containing quaternary ammonium salt in the embodiments contains a B-OH structure, which can condense with the hydroxyl groups on the surface of titanium dioxide and hollow glass microspheres, thereby achieving the purpose of dispersing inorganic particles. Comparative Example 3 does not contain this structure, therefore its thermal insulation performance is inferior to that of the embodiments. Furthermore, the table above also shows that the coatings prepared by this invention have excellent flame retardant properties, and the synergistic flame retardant effect of coatings containing both modified hollow glass microspheres and diene-containing quaternary ammonium salts is even better.

[0069] The mechanical properties of the coating were tested using a paint film impact tester.

[0070] Table 2:

[0071]

[0072] As shown in Table 2, the coating prepared by this invention has excellent mechanical properties. Furthermore, the mechanical properties of the coating using unmodified hollow glass microspheres in Comparative Example 2 are inferior to those of the example containing modified hollow glass microspheres. Comparative Example 3 does not contain diene-containing quaternary ammonium salts. In Comparative Example 4, in step A1, a commercially available quaternary ammonium salt antibacterial agent was used instead of the diene-containing quaternary ammonium salt, and both examples exhibited poor mechanical properties. This indicates that the presence of diene-containing quaternary ammonium salts is beneficial for improving the mechanical properties of the coating.

[0073] The antibacterial properties of the coating were tested in accordance with GB / T21866-2008.

[0074] Table 3:

[0075]

[0076] As shown in Table 3, the coating prepared by the present invention has a better antibacterial effect. The antibacterial performance of Comparative Example 3, which does not contain diene-containing gemini quaternary ammonium salt, is poor. Comparative Example 4 uses a commercially available quaternary ammonium salt antibacterial agent instead of diene-containing gemini quaternary ammonium salt, and its antibacterial performance is not as good as that of the embodiments of the present invention. The possible reasons are: firstly, the antibacterial performance of mono-mer quaternary ammonium salt is not as good as that of gemini quaternary ammonium salt; secondly, small molecule quaternary ammonium salt antibacterial agents are easy to precipitate. Therefore, the coating of Comparative Example 4 precipitates during the preparation process, and its antibacterial performance is not as good as that of the embodiments of the present invention. In the embodiments of the present invention, the diene structure is used to confine the small molecule gemini quaternary ammonium salt into the macromolecule, and the larger crosslinking density restricts the precipitation of small molecules, thereby improving the antibacterial performance of the coating.

[0077] The above description of the embodiments is provided to enable those skilled in the art to understand and apply the present invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the embodiments described herein, and any modifications made to the present invention by those skilled in the art based on the disclosure thereof should be within the scope of protection of the present invention.

Claims

1. An infrared reflective composite thermal barrier coating, characterized in that, The coating comprises the following raw materials by weight: 10-20 parts by weight of pure acrylic emulsion, 10-20 parts by weight of silicone acrylic emulsion, 5-10 parts by weight of modified styrene-acrylic emulsion, 0.3-1 part by weight of dispersant, 0.1-0.5 part by weight of defoaming agent, 0.1-0.5 part by weight of wetting agent, 1-3 parts by weight of thickening agent, 0.1-0.5 part by weight of film-forming aid, 3-8 parts by weight of titanium white, 5-10 parts by weight of modified hollow glass microbeads, 2 parts by weight of far infrared ceramic powder, and the balance is deionized water; The preparation method of the infrared reflective composite thermal insulation coating comprises the following steps: Step A1, dissolve the emulsifier in deionized water, stir and disperse, pass nitrogen, heat to 50-60℃, add initiator, styrene, methyl methacrylate, acrylic acid, double-olefin double-quinolinium salt to the above solution, stir for 3-5h, after the reaction is completed, cool down, discharge, get modified styrene-acrylic emulsion; Step A2, add dispersant, defoaming agent, wetting agent to deionized water, stir and mix evenly, then add titanium white, far infrared ceramic powder, stir and disperse, add pure acrylic emulsion, silicone acrylic emulsion, modified styrene-acrylic emulsion, film-forming aid and stir for 5-10min, finally add modified hollow glass microbeads and thickening agent, continue to stir for 5-10min, get infrared reflective composite thermal insulation coating.

2. The infrared reflective composite thermal barrier coating of claim 1, wherein, In step A1, the mass ratio of emulsifier, initiator, styrene, methyl methacrylate, acrylic acid, double-olefin double-quinolinium salt is 10-15:1-3:100:10-30:20-40:10-30.

3. The infrared reflective composite thermal barrier coating of claim 1, wherein, The preparation method of the modified hollow glass microbeads comprises the following steps: Add clean hollow glass microbeads to ethanol, slowly stir for 10-12h, filter, dry, then add to cerium nitrate aqueous solution, ultrasonic dispersion, slowly stir for 10-12h, filter, dry, get modified hollow glass microbeads.

4. The infrared reflective composite thermal barrier coating of claim 3, wherein, The concentration of the cerium nitrate aqueous solution is 1-2%.

5. The infrared reflective composite thermal barrier coating of claim 1, wherein, The preparation method of the double-olefin double-quinolinium salt comprises the following steps: Step A11, dissolve 1,4-piperazine diethylamine in ethanol, add 4-formylphenylboronic acid, stir at room temperature for 10-12h, after the reaction is completed, filter, ethanol wash, dry, get intermediate 1; Step A12, add intermediate 1 to acetone solvent, then add allyl chloride, stir and disperse, reflux for 8-10h, after the reaction is completed, suction filter, acetone wash the precipitate, recrystallize, get double-olefin double-quinolinium salt.

6. The infrared reflective composite thermal barrier coating of claim 5, wherein, In step A11, the molar ratio of 1,4-piperazine diethylamine and 4-formylphenylboronic acid is 1:2-2.

1.

7. The infrared reflective composite thermal barrier coating of claim 5, wherein, In step A12, the molar ratio of intermediate 1 and allyl chloride is 1:2.5-3.

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