Aerogel thermal barrier coating and method of making same

Abstract

The present application relates to the technical field of paint, and proposes an aerogel heat-insulating paint and a preparation method thereof.The aerogel heat-insulating paint comprises the following components in parts by weight: 8-12 parts of water, 15-25 parts of waterborne silicone-acrylate emulsion, 12-20 parts of styrene-acrylate emulsion, 3-5 parts of chopped fiber, 12-16 parts of hollow glass microsphere, 12-18 parts of silica aerogel, 2.3-3.6 parts of filler, 4-7 parts of flame retardant, and 1.6-4 parts of additive; the filler is titanium dioxide, aluminum oxide and modified magnesium oxide in a mass ratio of 0.8:1.2:0.6-1.4; and the modified magnesium oxide is magnesium fluoride-coated magnesium oxide.The above technical solution solves the problem of insufficient heat insulation of the aerogel heat-insulating paint in the prior art.

Description

Technical Field

[0001] This invention relates to the field of coating technology, specifically to an aerogel thermal insulation coating and its preparation method. Background Technology

[0002] Existing technologies using traditional insulation materials (such as aluminum silicate wool, rock wool, glass panels, calcium silicate boards, and perlite pipe shells) have significant drawbacks. On the one hand, long-term use easily leads to cracking and water seepage, resulting in a decrease in insulation effectiveness. On the other hand, to meet basic insulation requirements, the materials need to be quite thick, consuming more raw materials, extending the construction period, and increasing construction costs. To overcome the shortcomings of these traditional insulation materials, thermal insulation coatings have been developed both domestically and internationally as alternatives in recent years. Traditional thermal insulation coatings have been widely used in various fields, but due to their high thermal conductivity and low surface strength, they cannot meet the ever-increasing insulation demands of various industries. Therefore, researching high-performance thermal insulation coatings is key to solving these problems and meeting the rapidly evolving technological requirements of various industries. Summary of the Invention

[0003] This invention proposes an aerogel thermal insulation coating and its preparation method, which solves the problem of insufficient thermal insulation performance of aerogel thermal insulation coatings in related technologies.

[0004] The technical solution of the present invention is as follows:

[0005] This invention proposes an aerogel thermal insulation coating, comprising the following components in parts by weight: 8-12 parts deionized water, 15-25 parts water-based silicone-acrylic emulsion, 12-20 parts styrene-acrylic emulsion, 3-5 parts chopped fibers, 12-16 parts hollow glass microspheres, 12-18 parts silica aerogel, 2.3-3.6 parts filler, 4-7 parts flame retardant, and 1.6-4 parts additives;

[0006] The filler comprises titanium dioxide, aluminum oxide, and modified magnesium oxide in a mass ratio of 0.8:1.2:0.6~1.4;

[0007] The modified magnesium oxide is magnesium oxide coated with magnesium fluoride.

[0008] As a further technical solution, the mass ratio of titanium dioxide, aluminum oxide and magnesium fluoride coated magnesium oxide is 0.8:1.2:1.0~1.2.

[0009] In the filler of the aerogel thermal insulation coating of the present invention, when the mass ratio of titanium dioxide, aluminum oxide and magnesium fluoride coated magnesium oxide is 0.8:1.2:1.0~1.2, the synergistic effect of the three is further enhanced, significantly improving the thermal insulation performance of the aerogel thermal insulation coating.

[0010] As a further technical solution, the chopped fibers include one or both of glass fibers and basalt fibers.

[0011] As a further technical solution, the flame retardant includes aluminum hydroxide and pretreated magnesium hydroxide in a mass ratio of 1:0.7~0.9.

[0012] As a further technical solution, the pretreated magnesium hydroxide is diatomaceous earth-loaded magnesium hydroxide.

[0013] In the flame retardant of the aerogel thermal insulation coating of the present invention, aluminum hydroxide produces an alumina protective film when heated, which hinders the contact between oxygen and combustible substances; diatomaceous earth loaded with magnesium hydroxide is used as a flame retardant. The porous structure of diatomaceous earth can absorb heat and slow down the rate at which heat is transferred to the coating matrix. Moreover, the porous structure helps the dispersion of magnesium hydroxide, allowing it to exert its flame retardant effect more fully. When aluminum hydroxide and diatomaceous earth loaded with magnesium hydroxide are used in a mass ratio of 1:0.7~0.9, a more perfect barrier layer is formed, thereby significantly improving the flame retardant performance of the aerogel thermal insulation coating.

[0014] As a further technical solution, the additives include the following components in parts by weight: 0.4 to 1.0 parts of dispersant, 0.2 to 1.0 parts of defoamer, and 1 to 2 parts of film-forming aid.

[0015] As a further technical solution, the dispersant includes polyphosphate dispersants.

[0016] As a further technical solution, the defoamer includes polyether-modified silicone defoamers.

[0017] As a further technical solution, the film-forming aid includes dodecyl alcohol ester.

[0018] As a further technical solution, the preparation process of the magnesium fluoride-coated magnesium oxide includes the following steps:

[0019] Water is added to magnesium oxide to obtain a magnesium oxide suspension; hydrogen fluoride solution is added to the magnesium oxide suspension, the mixture is dried, and calcined to obtain magnesium oxide coated with magnesium fluoride.

[0020] As a further technical solution, the mass ratio of magnesium oxide to water is 2:0.8~1.2.

[0021] As a further technical solution, the volume concentration of the hydrogen fluoride solution is 40%~50%.

[0022] As a further technical solution, the mass ratio of magnesium oxide to hydrogen fluoride solution is 1:1.6~3.0.

[0023] As a further technical solution, the drying temperature is 80~100℃ and the time is 8~10h.

[0024] As a further technical solution, the calcination temperature is 580~620℃, the time is 2.5~3.5h, and the atmosphere is nitrogen.

[0025] As a further technical solution, the preparation process of the diatomaceous earth-supported magnesium hydroxide includes the following steps:

[0026] Diatomaceous earth is calcined and ground for the first time to obtain diatomaceous earth powder. Water and magnesium chloride are added to the diatomaceous earth powder, stirred, and then sodium hydroxide is added. The mixture is reacted, aged, filtered, washed, dried, and ground for the second time to obtain diatomaceous earth-loaded magnesium hydroxide.

[0027] As a further technical solution, the calcination temperature is 425~475℃ and the time is 1.5~2.5h.

[0028] As a further technical solution, the particle size of the diatomaceous earth powder is 100~120μm.

[0029] As a further technical solution, the stirring rate is 300~400 rpm and the time is 10~12 min.

[0030] As a further technical solution, the mass ratio of the diatomaceous earth powder, water and magnesium chloride is 2:16:1~1.5.

[0031] As a further technical solution, the mass ratio of magnesium chloride to sodium hydroxide is 19:22~25.

[0032] As a further technical solution, the reaction temperature is 40~50℃ and the time is 25~35min.

[0033] As a further technical solution, the aging time is 55-65 minutes.

[0034] As a further technical solution, the washing solution is water.

[0035] As a further technical solution, the drying temperature is 100~110℃ and the time is 4~6h.

[0036] As a further technical solution, the particle size of the diatomaceous earth-loaded magnesium hydroxide is 50~80μm.

[0037] This invention also proposes a method for preparing an aerogel thermal insulation coating, comprising the following steps:

[0038] Water, dispersant, and defoamer are mixed, short-cut fibers are added and stirred, then silica aerogel is added and dispersed. Styrene-acrylic emulsion, water-based silicone-acrylic emulsion, film-forming aid, flame retardant, filler, and hollow glass microspheres are added in sequence and stirred to obtain an aerogel thermal insulation coating.

[0039] The working principle and beneficial effects of this invention are as follows:

[0040] In this invention, magnesium oxide coated with titanium dioxide, alumina, and magnesium fluoride is used as a filler, which significantly improves the thermal insulation of the aerogel thermal insulation coating. Titanium dioxide acts as a heat insulation agent, and the low thermal conductivity of alumina reduces heat conduction, further enhancing the thermal insulation effect. Magnesium oxide coated with magnesium fluoride is used as a filler. Magnesium oxide itself has certain thermal insulation properties, while the coating of magnesium fluoride improves the surface properties of magnesium oxide, reduces agglomeration, and makes the entire filler system more uniformly dispersed in the aerogel. Moreover, magnesium fluoride can effectively block infrared radiation heat transfer, further improving the thermal insulation performance of the coating. When titanium dioxide, alumina, and magnesium fluoride coated magnesium oxide are used in combination, the three produce a synergistic effect, comprehensively improving the thermal insulation performance of the aerogel thermal insulation coating. Detailed Implementation

[0041] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0042] In the following embodiments and comparative examples,

[0043] Water-based silicone-acrylic emulsion: Model number ZN, manufacturer is Zhongnuo Environmental Protection Technology (Guangdong) Co., Ltd.;

[0044] Styrene-acrylic emulsion: Manufacturer is Jinan Tiantan Chemical Co., Ltd.;

[0045] Hollow glass microspheres: Model CL100, manufactured by Shanghai Weiyi New Materials Co., Ltd.

[0046] Silica aerogel: Model MT1200, manufactured by Shanghai Zhenlishi Network Technology Co., Ltd.

[0047] Titanium dioxide: Model BT-FR203M, manufactured by Jinan Yongyue Chemical Co., Ltd.

[0048] Alumina: Model J600, manufactured by Lingshou County Jinyuan Mining Processing Plant;

[0049] Glass fiber: 3mm in length and 10μm in diameter;

[0050] Basalt fiber: 6mm in length and 1mm in thickness, manufactured by Shijiazhuang Chenjin Mineral Products Co., Ltd.

[0051] Polyphosphate dispersant: Model BG1900, manufactured by Nanjing Baiju Technology Co., Ltd.

[0052] Polyether-modified silicone defoamer: Model: TEGO FOAMEX, Manufacturer: Shanghai Zhenlishi Network Technology Co., Ltd.

[0053] Dodecyl alcohol ester: The manufacturer is Jiangyin Ourui Chemical New Material Co., Ltd.

[0054] Example 1

[0055] An aerogel thermal insulation coating comprises the following components in parts by weight: 8 parts deionized water, 15 parts water-based silicone-acrylic emulsion, 12 parts styrene-acrylic emulsion, 3 parts glass fiber, 12 parts hollow glass microspheres, 12 parts silica aerogel, 2.3 parts filler, 4 parts flame retardant, and 1.6 parts additives.

[0056] The filler is a mixture of titanium dioxide, alumina, and magnesium fluoride coated with magnesium oxide in a mass ratio of 0.8:1.2:0.6.

[0057] The flame retardant is diatomaceous earth-loaded magnesium hydroxide;

[0058] The additives include the following components in parts by weight: 0.4 parts of polyphosphate dispersant, 0.2 parts of polyether-modified silicone defoamer, and 1 part of dodecyl alcohol ester;

[0059] The preparation process of magnesium oxide coated with magnesium fluoride includes the following steps:

[0060] Water was added to magnesium oxide (mass ratio of magnesium oxide to water was 2:0.8) to obtain a magnesium oxide suspension; a 40% hydrogen fluoride solution (mass ratio of magnesium oxide to hydrogen fluoride solution was 1:1.6) was added to the magnesium oxide suspension, dried at 80℃ for 10h, and then calcined at 580℃ for 3.5h in a nitrogen atmosphere to obtain magnesium oxide coated with magnesium fluoride.

[0061] The preparation process of diatomaceous earth-supported magnesium hydroxide includes the following steps:

[0062] Diatomaceous earth was calcined at 425℃ for 2.5 h and then ground to a particle size of 100 μm to obtain diatomaceous earth powder. Water and magnesium chloride (mass ratio of diatomaceous earth powder, water and magnesium chloride was 2:16:1) were added to the diatomaceous earth powder and stirred at 300 rpm for 12 min. Then sodium hydroxide (mass ratio of magnesium chloride to sodium hydroxide was 19:22) was added, and the mixture was reacted at 40℃ for 35 min, aged for 55 min, filtered, washed with water 3 times, dried at 100℃ for 6 h, and ground again to obtain diatomaceous earth-loaded magnesium hydroxide with a particle size of 50 μm.

[0063] The preparation process of an aerogel thermal insulation coating includes the following steps:

[0064] Deionized water, polyphosphate dispersant, and polyether-modified silicone defoamer were mixed, glass fiber was added and stirred for 10 minutes, then silica aerogel was added and dispersed at 1200 r / min for 30 minutes. Styrene-acrylic emulsion, water-based silicone-acrylic emulsion, dodecyl alcohol ester, flame retardant, and hollow glass microspheres were added in sequence and stirred evenly to obtain aerogel thermal insulation coating.

[0065] Example 2

[0066] An aerogel thermal insulation coating comprises the following components in parts by weight: 12 parts deionized water, 25 parts water-based silicone-acrylic emulsion, 20 parts styrene-acrylic emulsion, 5 parts basalt fiber, 16 parts hollow glass microspheres, 18 parts silica aerogel, 3.6 parts filler, 7 parts flame retardant, and 4 parts additives.

[0067] The filler is a mixture of titanium dioxide, alumina, and magnesium fluoride coated with magnesium oxide in a mass ratio of 0.8:1.2:1.4.

[0068] The flame retardant is diatomaceous earth-loaded magnesium hydroxide;

[0069] The additives include the following components in parts by weight: 1.0 part of polyphosphate dispersant, 1.0 part of polyether-modified silicone defoamer, and 2 parts of dodecyl alcohol ester;

[0070] The preparation process of magnesium oxide coated with magnesium fluoride includes the following steps:

[0071] Water was added to magnesium oxide (mass ratio of magnesium oxide to water was 2:1.2) to obtain a magnesium oxide suspension; a 50% hydrogen fluoride solution (mass ratio of magnesium oxide to hydrogen fluoride solution was 1:3.0) was added to the magnesium oxide suspension, dried at 100℃ for 8 hours, and then calcined at 620℃ for 2.5 hours in a nitrogen atmosphere to obtain magnesium oxide coated with magnesium fluoride.

[0072] The preparation process of diatomaceous earth-supported magnesium hydroxide includes the following steps:

[0073] Diatomaceous earth was calcined at 475℃ for 1.5h and then ground to a particle size of 120μm to obtain diatomaceous earth powder. Water and magnesium chloride (mass ratio of diatomaceous earth powder, water and magnesium chloride was 2:16:1.5) were added to the diatomaceous earth powder and stirred at 400rpm for 10min. Then sodium hydroxide (mass ratio of magnesium chloride to sodium hydroxide was 19:25) was added, and the mixture was reacted at 50℃ for 25min, aged for 65min, filtered, washed three times with water, dried at 110℃ for 4h, and ground again to obtain diatomaceous earth-loaded magnesium hydroxide with a particle size of 80μm.

[0074] The preparation process of an aerogel thermal insulation coating includes the following steps:

[0075] Deionized water, polyphosphate dispersant, and polyether-modified silicone defoamer were mixed, basalt fiber was added and stirred for 10 min, then silica aerogel was added and dispersed at 1200 r / min for 30 min. Styrene-acrylic emulsion, water-based silicone-acrylic emulsion, dodecyl alcohol ester, flame retardant, and hollow glass microspheres were added in sequence and stirred evenly to obtain aerogel thermal insulation coating.

[0076] Example 3

[0077] An aerogel thermal insulation coating comprises the following components in parts by weight: 10 parts deionized water, 20 parts water-based silicone-acrylic emulsion, 15 parts styrene-acrylic emulsion, 4 parts basalt fiber, 14 parts hollow glass microspheres, 14 parts silica aerogel, 3.0 parts filler, 6 parts flame retardant, and 2.8 parts additives.

[0078] The filler is a mixture of titanium dioxide, alumina, and magnesium fluoride coated with magnesium oxide in a mass ratio of 0.8:1.2:1.3.

[0079] The flame retardant is aluminum hydroxide;

[0080] The additives include the following components in parts by weight: 0.6 parts of polyphosphate dispersant, 0.7 parts of polyether-modified silicone defoamer, and 1.5 parts of dodecyl alcohol ester;

[0081] The preparation process of magnesium oxide coated with magnesium fluoride includes the following steps:

[0082] Water was added to magnesium oxide (mass ratio of magnesium oxide to water was 2:1.0) to obtain a magnesium oxide suspension; a 45% hydrogen fluoride solution (mass ratio of magnesium oxide to hydrogen fluoride solution was 1:2.0) was added to the magnesium oxide suspension, dried at 90℃ for 9 hours, and then calcined at 600℃ for 3 hours in a nitrogen atmosphere to obtain magnesium oxide coated with magnesium fluoride.

[0083] The preparation process of an aerogel thermal insulation coating includes the following steps:

[0084] Deionized water, polyphosphate dispersant, and polyether-modified silicone defoamer were mixed, basalt fiber was added and stirred for 10 min, then silica aerogel was added and dispersed at 1200 r / min for 30 min. Styrene-acrylic emulsion, water-based silicone-acrylic emulsion, dodecyl alcohol ester, flame retardant, and hollow glass microspheres were added in sequence and stirred evenly to obtain aerogel thermal insulation coating.

[0085] Example 4

[0086] The only difference between this embodiment and Example 3 is that the mass ratio of titanium dioxide, aluminum oxide and magnesium fluoride coated magnesium oxide is 0.8:1.2:1.2.

[0087] Example 5

[0088] The only difference between this embodiment and Example 3 is that the mass ratio of titanium dioxide, aluminum oxide and magnesium fluoride coated magnesium oxide is 0.8:1.2:1.0.

[0089] Example 6

[0090] The only difference between this embodiment and Embodiment 3 is that the mass ratio of titanium dioxide, aluminum oxide, and magnesium oxide coated with magnesium fluoride is 0.8:1.2:0.8.

[0091] Example 7

[0092] The only difference between this embodiment and Embodiment 4 is that the flame retardant is diatomaceous earth-loaded magnesium hydroxide;

[0093] The preparation process of diatomaceous earth-supported magnesium hydroxide includes the following steps:

[0094] Diatomaceous earth was calcined at 450℃ for 2.0 h and then ground to a particle size of 110 μm to obtain diatomaceous earth powder. Water and magnesium chloride (mass ratio of diatomaceous earth powder, water and magnesium chloride was 2:16:1.5) were added to the diatomaceous earth powder and stirred at 350 rpm for 11 min. Then sodium hydroxide (mass ratio of magnesium chloride to sodium hydroxide was 19:23) was added, and the mixture was reacted at 45℃ for 30 min, aged for 60 min, filtered, washed with water 3 times, dried at 105℃ for 5 h, and ground again to obtain diatomaceous earth-loaded magnesium hydroxide with a particle size of 65 μm.

[0095] Example 8

[0096] The only difference between this embodiment and Embodiment 4 is that the flame retardant is aluminum hydroxide and magnesium hydroxide supported on diatomaceous earth in a mass ratio of 1:0.7;

[0097] The preparation process of diatomaceous earth-supported magnesium hydroxide includes the following steps:

[0098] Diatomaceous earth was calcined at 450℃ for 2.0 h and then ground to a particle size of 110 μm to obtain diatomaceous earth powder. Water and magnesium chloride (mass ratio of diatomaceous earth powder, water and magnesium chloride was 2:16:1.5) were added to the diatomaceous earth powder and stirred at 350 rpm for 11 min. Then sodium hydroxide (mass ratio of magnesium chloride to sodium hydroxide was 19:23) was added, and the mixture was reacted at 45℃ for 30 min, aged for 60 min, filtered, washed with water 3 times, dried at 105℃ for 5 h, and ground again to obtain diatomaceous earth-loaded magnesium hydroxide with a particle size of 65 μm.

[0099] Example 9

[0100] The only difference between this embodiment and Embodiment 4 is that the flame retardant is aluminum hydroxide and magnesium hydroxide supported on diatomaceous earth in a mass ratio of 1:0.9;

[0101] The preparation process of diatomaceous earth-supported magnesium hydroxide includes the following steps:

[0102] Diatomaceous earth was calcined at 450℃ for 2.0 h and then ground to a particle size of 110 μm to obtain diatomaceous earth powder. Water and magnesium chloride (mass ratio of diatomaceous earth powder, water and magnesium chloride was 2:16:1.5) were added to the diatomaceous earth powder and stirred at 350 rpm for 11 min. Then sodium hydroxide (mass ratio of magnesium chloride to sodium hydroxide was 19:23) was added, and the mixture was reacted at 45℃ for 30 min, aged for 60 min, filtered, washed with water 3 times, dried at 105℃ for 5 h, and ground again to obtain diatomaceous earth-loaded magnesium hydroxide with a particle size of 65 μm.

[0103] Comparative Example 1

[0104] The only difference between this comparative example and Example 3 is that the filler is titanium dioxide and aluminum oxide in a mass ratio of 0.8:1.2.

[0105] Comparative Example 2

[0106] The only difference between this comparative example and Example 3 is that the filler is titanium dioxide and magnesium fluoride coated magnesium oxide in a mass ratio of 0.8:1.3.

[0107] Comparative Example 3

[0108] The only difference between this comparative example and Example 3 is that the filler is magnesium oxide coated with alumina and magnesium fluoride in a mass ratio of 1.2:1.3.

[0109] The aerogel thermal insulation coatings prepared in Examples 1-9 and Comparative Examples 1-3 were tested according to the following method:

[0110] 1. Thermal conductivity: The test method specified in GB / T 22588-2008 "Measurement of thermal diffusivity or thermal conductivity by flash method" shall be followed.

[0111] 2. Ignition time: Tested according to the method specified in ISO 5660-1 "Test methods for heat release rate and smoke generation rate of building materials";

[0112] 3. Compatibility: In accordance with the standards specified in T / CECS 10126-2021 "Aerogel Insulation Thick Coating System";

[0113] The test results are shown in Table 1:

[0114] Table 1 Performance test results of aerogel thermal insulation coatings prepared in Examples 1-9 and Comparative Examples 1-3

[0115]

[0116] 1. Compared with Comparative Examples 1 to 3, the thermal conductivity of the aerogel insulation coatings prepared in Examples 1 to 9 is lower than that of the aerogel insulation coatings prepared in Comparative Examples 1 to 3, indicating that the combination of titanium dioxide, alumina and magnesium fluoride-coated magnesium oxide improves the insulation performance of the aerogel insulation coating; the aerogel insulation coatings prepared in the examples also show excellent performance in terms of water resistance and freeze-thaw resistance.

[0117] 2. Compared with Examples 3 to 6, the thermal conductivity of the aerogel insulation coatings prepared in Examples 4 to 5 is significantly lower than that of the aerogel insulation coatings prepared in Examples 3 and 6. This indicates that further limiting the mass ratio of titanium dioxide, aluminum oxide and magnesium fluoride coated magnesium oxide to 0.8:1.2:1.0~1.2 significantly improves the insulation performance of the aerogel insulation coating.

[0118] 3. Compared with Examples 8-9, the aerogel insulation coatings prepared in Examples 8-9 have a longer ignition time than those prepared in Examples 4 and 7. This indicates that using aluminum hydroxide and diatomaceous earth-loaded magnesium hydroxide as flame retardants can improve the flame retardant performance of aerogel insulation coatings.

[0119] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An aerogel thermal insulation coating, characterized in that, The product comprises the following components in parts by weight: 8-12 parts water, 15-25 parts water-based silicone-acrylic emulsion, 12-20 parts styrene-acrylic emulsion, 3-5 parts chopped fibers, 12-16 parts hollow glass microspheres, 12-18 parts silica aerogel, 2.3-3.6 parts filler, 4-7 parts flame retardant, and 1.6-4 parts additives; The filler is titanium dioxide, aluminum oxide and modified magnesium oxide in a mass ratio of 0.8:1.2:0.6~1.4; The modified magnesium oxide is magnesium oxide coated with magnesium fluoride; The preparation process of magnesium oxide coated with magnesium fluoride includes the following steps: Water is added to magnesium oxide to obtain a magnesium oxide suspension; hydrogen fluoride solution is added to the magnesium oxide suspension, the mixture is dried, and calcined to obtain magnesium oxide coated with magnesium fluoride.

2. The aerogel thermal insulation coating according to claim 1, characterized in that, The mass ratio of titanium dioxide, aluminum oxide and magnesium fluoride coated magnesium oxide is 0.8:1.2:1.0~1.

2.

3. The aerogel thermal insulation coating according to claim 1, characterized in that, The chopped fibers include one or both of glass fibers and basalt fibers.

4. The aerogel thermal insulation coating according to claim 1, characterized in that, The flame retardant comprises aluminum hydroxide and pretreated magnesium hydroxide in a mass ratio of 1:0.7~0.9; The pretreated magnesium hydroxide is diatomaceous earth-loaded magnesium hydroxide.

5. The aerogel thermal insulation coating according to claim 1, characterized in that, The additives comprise the following components in parts by weight: 0.4-1.0 parts of dispersant, 0.2-1.0 parts of defoamer, and 1-2 parts of film-forming aid; The dispersant includes polyphosphate dispersants; The defoamer includes polyether-modified silicone defoamers; The film-forming aid includes dodecyl alcohol ester.

6. The aerogel thermal insulation coating according to claim 1, characterized in that, In the preparation process of magnesium oxide coated with magnesium fluoride, the mass ratio of magnesium oxide to water is 2:0.8~1.2; The volume concentration of the hydrogen fluoride solution is 40%~50%; The mass ratio of magnesium oxide to hydrogen fluoride solution is 1:1.6~3.0; The calcination temperature is 580~620℃, the time is 2.5~3.5h, and the atmosphere is nitrogen.

7. The aerogel thermal insulation coating according to claim 4, characterized in that, The preparation process of the diatomaceous earth-supported magnesium hydroxide includes the following steps: Diatomaceous earth is calcined and ground for the first time to obtain diatomaceous earth powder. Water and magnesium chloride are added to the diatomaceous earth powder, stirred, and then sodium hydroxide is added. The mixture is reacted, aged, filtered, washed, dried, and ground for the second time to obtain diatomaceous earth-loaded magnesium hydroxide.

8. The aerogel thermal insulation coating according to claim 7, characterized in that, The roasting temperature is 425~475℃, and the time is 1.5~2.5h; The particle size of the diatomaceous earth powder is 100~120μm; The mass ratio of the diatomaceous earth powder, water, and magnesium chloride is 2:16:1~1.5; The mass ratio of magnesium chloride to sodium hydroxide is 19:22~25; The reaction is carried out at a temperature of 40-50°C for 25-35 minutes. The aging time is 55-65 minutes; The particle size of the diatomaceous earth-loaded magnesium hydroxide is 50~80μm.

9. A method for preparing an aerogel thermal insulation coating, used to prepare the aerogel thermal insulation coating according to any one of claims 5 to 8, characterized in that, Includes the following steps: Water, dispersant, and defoamer are mixed, short-cut fibers are added and stirred, then silica aerogel is added and dispersed. Styrene-acrylic emulsion, water-based silicone-acrylic emulsion, film-forming aid, flame retardant, filler, and hollow glass microspheres are added in sequence and stirred to obtain an aerogel thermal insulation coating.

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