Heat-insulating coating with high temperature resistance, high strength and low heat conductivity coefficient and preparation method of heat-insulating coating

Abstract

The invention belongs to the technical field of functional materials, and particularly relates to a high-temperature-resistant high-strength low-heat-conductivity-coefficient heat-insulating coating and a preparation method thereof.The heat-insulating coating takes phenylene organic silicon resin as a film forming matter, takes aminopropyl-terminated methyl phenyl silicone rubber as a toughening agent and takes aerogel powder and glass beads as heat-insulating filler. The aerogel heat insulation coating has the characteristics of high temperature resistance, low heat conductivity coefficient, high strength and the like, can be used for a long time in a high-temperature environment of 300 DEG C or above, and meets the requirements of high-temperature application scenes such as projectile weapons, ship equipment, industrial kilns, chemical pipe networks and the like on high-performance heat insulation coatings.

Description

Technical Field

[0001] The present invention belongs to the technical field of functional materials, and in particular relates to a high-temperature resistant, high-strength, low-thermal conductivity thermal insulation coating and a preparation method thereof. Background Art

[0002] Thermal insulation refers to the process of using technical means to hinder the transfer of heat flow in order to achieve temperature control. Depending on the intended use, thermal insulation technology can be divided into two main application scenarios. The first is to block the influx of external heat, preventing the external heat flow from causing a rapid increase in internal temperature, and playing a role in thermal shock protection, such as the thermal insulation protection of internal cables of missile weapons, rocket engine nozzles, ship launch silos, etc. The second is to prevent the outflow of internal heat when the internal temperature is significantly higher than the ambient temperature, and maintain internal temperature stability, such as thermal insulation in scenarios such as polar scientific research equipment, chemical high-temperature pipelines, and industrial kilns.

[0003] Thermal insulation is typically achieved through the use of insulating materials, including insulation foam, insulation fiber felt, insulation boards, and insulation coatings. Commonly used insulation materials include rock wool, phenolic foam, and polyurethane foam. Insulation coatings are functional coatings based on organic / inorganic polymers, achieving their thermal insulation properties through the addition of insulating fillers such as hollow glass microspheres and hollow phenolic microspheres. Compared to other insulation materials like insulation foam and insulation boards, insulation coatings offer superior construction processability, providing uniform insulation coverage for various irregular structures and preventing heat leakage caused by gaps in insulation boards.

[0004] Aerogel thermal insulation coating is a new type of thermal insulation coating that has developed rapidly in recent years. By adding aerogel powder with excellent thermal insulation properties to the polymer matrix, it can effectively reduce the thermal conductivity of the coating and greatly improve the thermal insulation effect of the material, such as invention patents CN2023117621963, CN202411074927X, CN2024105815765, etc. With the continuous development of the application scenarios of aerogel thermal insulation coatings, their operating temperature is gradually increasing. For example, in missile weapons, ship equipment, industrial kilns, chemical pipelines, etc., the coating is required to maintain stable thermal insulation performance for a long time in an environment of 300°C, but the current aerogel thermal insulation coatings are difficult to meet the relevant requirements: on the one hand, the operating temperature of existing aerogel thermal insulation coatings is generally within 200°C, which is difficult to adapt to long-term use temperatures above 300°C; on the other hand, the realization of low thermal conductivity requires the addition of a large amount of aerogel powder, but the addition of a large amount of aerogel powder is prone to uneven dispersion, agglomeration, etc., and greatly reduces the adhesion of the coating, making it difficult to achieve a balance between coating strength, thermal conductivity and adhesion; at the same time, in high-temperature use environments, aerogel thermal insulation coatings are prone to cracking or even falling off due to the thermal expansion of the base metal, resulting in failure of the thermal insulation function. These problems greatly limit the application of aerogel thermal insulation coatings in high-temperature scenarios. Summary of the Invention

[0005] The purpose of the present invention is to meet the demand for long-term stable thermal insulation in application scenarios above 300°C, and to propose a high-temperature resistant, high-strength, low thermal conductivity thermal insulation coating and its preparation method, so as to solve the problems of existing aerogel thermal insulation coatings such as low long-term use temperature, low thermal insulation efficiency, poor coating strength, and cracking at high temperatures, and to meet the urgent demand for high-performance thermal insulation coatings in high-temperature application scenarios such as missile weapons, ship equipment, industrial kilns, and chemical pipelines.

[0006] To solve the above technical problems, the present invention proposes a high-temperature resistant, high-strength, low-thermal-conductivity thermal insulation coating, the specific concept is as follows: Phenylene silicone resin is used as the polymer film-forming material. The presence of phenylene groups further enhances the heat resistance of silicone resin and greatly improves its mechanical strength. Compared with acrylic resin, alkyd resin, etc., aerogel thermal insulation coating made of phenylene silicone resin has outstanding high temperature resistance and can be used stably for a long time in an environment above 300℃, especially at 300℃-350℃.

[0007] Aminopropyl-terminated methylphenyl silicone rubber is used as a toughening agent, while aminopropylsilane is used to aminopropylate the phenylene silicone resin, and pentaerythrityl tetraacrylate is used as a crosslinker. This approach not only allows the aminopropyl groups to undergo an "amine-ene" click reaction with conjugated double bonds, enabling the coating to cure rapidly at room temperature, but also introduces low-molecular-weight silicone rubber into the resin's curing crosslinking network, effectively increasing its flexibility while maintaining the resin's heat resistance. This allows the coating to stretch and deform as the metal substrate expands, preventing cracking and shedding.

[0008] Using short-cut fibers to reinforce the coating can further improve the coating strength and prevent cracking; using large-particle aerogel powder and small-particle glass beads as thermal insulation fillers, the combination of large and small particle sizes makes the thermal insulation fillers more densely packed. At the same time, the addition of glass beads can reduce the use of aerogel powder and reduce the coating cost; using silane coupling agent KH-560 to modify the surface of aerogel powder and glass beads. The epoxy group of KH-560 can react with the hydroxyl and amino groups in phenylene silicone resin, which can effectively improve the compatibility of the thermal insulation filler, making it evenly dispersed in the coating and avoiding agglomeration.

[0009] The technical solution of this application solves the problems of low long-term use temperature, low thermal insulation efficiency, poor coating strength, and cracking at high temperatures of aerogel thermal insulation coatings, providing a high-performance thermal insulation coating for high-temperature application scenarios such as missile weapons, ship equipment, industrial kilns, and chemical pipelines.

[0010] Based on the above inventive concept, the present invention provides a high-temperature resistant, high-strength, low thermal conductivity thermal insulation coating, the raw material composition of which is divided into two components, A and B, by weight, respectively: Component A is composed of: silicone resin, 100 parts; aerogel powder, 15-40 parts; glass microspheres, 9-30 parts; reinforcing fiber, 1-3 parts; modifier, 3-7 parts; toughening agent, 3-7 parts; dispersant, 2-5 parts; diluent, 70-115 parts; Component B is a cross-linking agent.

[0011] When using, mix component A and component B in a mass ratio of 5:1 and spray them.

[0012] The organosilicon resin in component A is a phenylene organosilicon resin with a molecular weight Mw of 500 to 6000.

[0013] The aerogel powder is SiO2 aerogel powder with a particle size of 150 to 500 μm.

[0014] The glass microspheres are hollow glass microspheres with a particle size of 40 to 60 μm.

[0015] The reinforcing fiber is one of glass fiber, quartz fiber, aluminum silicate fiber, and mullite fiber, or a mixture of two thereof; further, the length of the reinforcing fiber is 5 to 10 mm.

[0016] The modifier is one of aminopropyltrimethoxysilane, aminopropyltriethoxysilane, aminopropylmethyldimethoxysilane and aminopropylmethyldiethoxysilane.

[0017] The toughening agent is aminopropyl-terminated methylphenyl silicone rubber with a molecular weight Mw of 500-2000.

[0018] The dispersant is one of BYK-333, HY-512, and MOK-5622.

[0019] The diluent is one of butanone, ethyl acetate and tetrahydrofuran.

[0020] The crosslinking agent of component B is a solution of isopentaerythritol tetraacrylate, and the solvent used is the same as the diluent in component A, with a mass fraction of 10-15%.

[0021] Furthermore, the inventors also provide a method for preparing the above-mentioned high-temperature resistant, high-strength, and low-thermal-conductivity thermal insulation coating, the specific steps of which are as follows: (1) Raw material preparation Weigh each raw material according to the ratio. Glass microspheres and aerogel powder are each soaked in a 30wt% KH-560 acetone solution for at least 24 hours. The solution is then filtered to remove the solution, and the powder is air-dried for later use. The silicone resin is first dissolved in toluene to prepare a 50wt% solution. The modifier is then added and stirred at 60°C for 1 hour. The solvent is then removed by vacuum distillation to obtain the modified silicone resin. (2) Preparation of aerogel thermal insulation coating The modified silicone resin and toughening agent are added to the diluent, stirred evenly, and then a dispersant is added and stirred thoroughly for 5 minutes; glass microspheres and aerogel powder are added and stirred thoroughly for 30 minutes; finally, reinforcing fibers are added and stirred thoroughly for 45 minutes to obtain component A of the aerogel thermal insulation coating; The isopentacryl tetraacrylate and the same solvent as the diluent in the A component are prepared into an isopentacryl tetraacrylate solution to obtain the aerogel thermal insulation coating component B; (3) Aerogel thermal insulation coating spraying Component A and component B are weighed respectively in a mass ratio of 5:1, and are fully stirred with a mixer; the coating is sprayed with a sprayer, and after spraying to a specified thickness, it is dried in a natural environment at room temperature for 24 hours to obtain an aerogel thermal insulation coating; wherein, the thickness of a single spraying does not exceed 2 mm, and the total thickness of multiple sprayings does not exceed 8 mm; when spraying multiple times, the coating after one spraying is surface dry (touch) before the next spraying.

[0022] Compared with the prior art, the above technical solution of the present invention has the following advantages: (1) High-temperature resistant phenylene silicone resin is used as the polymer film-forming material of the coating. The presence of phenylene groups further enhances the heat resistance of the silicone resin and greatly improves its mechanical strength, making the aerogel thermal insulation coating have outstanding high-temperature resistance and can be used stably for a long time in an environment above 300°C.

[0023] (2) High-temperature resistant methylphenyl silicone rubber is used as a toughening agent, and low molecular weight silicone rubber is introduced into the resin curing cross-linking network, which effectively increases the flexibility while ensuring the resin's heat resistance. It can make the coating stretch and deform as the metal substrate expands, avoiding cracking and falling off. At the same time, short-cut fibers are added to the coating components to further improve the strength of the coating and solve the problem of cracking of aerogel thermal insulation coatings at high temperatures.

[0024] (3) The present invention innovatively introduces click reaction into the curing mechanism of the coating. By constructing a large number of amino groups in the components and utilizing the "amine-ene" click reaction to achieve curing and cross-linking of the coating, the problem of high-temperature resistant resins being difficult to cure at room temperature is solved, thereby improving the processability of the coating.

[0025] (4) Silane coupling agent is used to modify the surface of the thermal insulation filler so that it can react chemically with the polymer or generate intermolecular forces, thereby solving the agglomeration problem of the thermal insulation filler and increasing the addition amount and dispersion uniformity of the thermal insulation filler.

[0026] In summary, the high-temperature resistant, high-strength, low-thermal-conductivity thermal insulation coating obtained by the above raw materials and preparation method has a density of 0.2 g / cm 3 ~0.5g / cm 3 , bonding strength ≥ 0.5MPa, room temperature thermal conductivity ≤ 0.035W / m·k, and thermal conductivity ≤ 0.06W / m·k at 300°C. Compared with aerogel thermal insulation coatings using acrylic resins, alkyd resins, and other film-forming materials, the aerogel thermal insulation coating of the present invention has the characteristics of high temperature resistance, low thermal conductivity, high strength, and good toughness. It can be used for a long time in high temperature environments above 300°C, especially 300°C-350°C, providing a high-performance thermal insulation coating for high-temperature applications such as missile weapons, ship equipment, industrial kilns, and chemical pipelines. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a photo of the cured product of the high-temperature resistant, high-strength, low-thermal-conductivity thermal insulation coating prepared in Example 1; Figure 2 This is a photo of the cured thermal insulation coating of high temperature resistance, high strength and low thermal conductivity prepared in Example 1 after being baked at 350° C. for 15 minutes; It can be seen that the prepared high-temperature resistant, high-strength, low thermal conductivity thermal insulation coating cured product did not experience cracking, falling off, coating decomposition and other problems after hot baking at 350°C, and has outstanding high-temperature resistance. DETAILED DESCRIPTION

[0028] The present invention will be further described below in conjunction with specific embodiments, which may enable those skilled in the art to more fully understand the present invention, but does not limit the present invention in any way. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of protection of the present invention.

[0029] The phenylene silicone resin used in the following examples was prepared by the hydrolysis-condensation method according to the scheme described in the literature (Z. Yang, S. Han, R. Zhang, S. Feng, C. Zhang, S. Zhang, Polymer Degradation and Stability, 2011, 96(12): 2145-2151); the aminopropyl-terminated methylphenyl silicone rubber was prepared according to the literature (Wang Gaiyun. Preparation and Performance Study of Polyimide-Siloxane Copolymers [D]. Shandong University, 2018.), and the molecular weights are all weight-average molecular weights; the remaining materials are all commercially available products.

[0030] Example 1 A method for preparing a high-temperature resistant, high-strength, low-thermal-conductivity thermal insulation coating, the specific steps are as follows: (1) Raw material preparation The raw materials used in component A are composed of the following by weight: phenylene silicone resin, molecular weight 6000, 100 parts; aminopropyl-terminated methylphenyl silicone rubber, molecular weight 2000, 3 parts; SiO2 aerogel powder, particle size 150-300 μm, 20 parts; glass microbeads, particle size 60 μm, 25 parts; glass fiber, length 7 mm, 2 parts; aminopropyltrimethoxysilane, 3 parts; BYK-333, 5 parts; butanone, 115 parts.

[0031] The component materials were weighed according to the above proportions, and the hollow glass microspheres and SiO2 aerogel powder were respectively placed in a 30wt% KH-560 acetone solution and soaked for 24 hours. The solution was filtered to remove the solution and then dried. Phenylene silicone resin was dissolved in toluene to prepare a 50wt% solution. After adding aminopropyltrimethoxysilane, the solution was stirred and reacted at 60°C for 1 hour. The solvent was removed by reduced pressure distillation to obtain a modified phenylene silicone resin.

[0032] (2) Preparation of aerogel thermal insulation coating Modified phenylene silicone resin and aminopropyl-terminated methylphenyl silicone rubber were added to butanone, stirred evenly, and then BYK-333 was added and stirred thoroughly for 5 minutes; hollow glass microspheres and SiO2 aerogel powder were added and stirred thoroughly for 30 minutes; finally, glass fiber was added and stirred thoroughly for 45 minutes to obtain component A of the aerogel thermal insulation coating; The aerogel thermal insulation coating component B was obtained by dissolving isopentamycin tetraacrylate in butanone to prepare an isopentamycin tetraacrylate solution with a concentration of 10 wt %.

[0033] (3) Aerogel thermal insulation coating spraying Component A and component B were weighed in a mass ratio of 5:1, and stirred thoroughly with an electric stirrer. The coating was sprayed with a pneumatic sprayer to a thickness of 1.5 mm. After drying at room temperature in a natural environment, the coating was sprayed to a thickness of 1.5 mm. Finally, the coating was dried at room temperature in a natural environment for 24 hours to obtain an aerogel thermal insulation coating. The properties of the coating are shown in Table 1.

[0034] Example 2 A method for preparing a high-temperature resistant, high-strength, low-thermal-conductivity thermal insulation coating, the specific steps are as follows: (1) Raw material preparation The raw materials used in component A are composed of the following by weight: phenylene silicone resin, molecular weight 3000, 100 parts; aminopropyl-terminated methylphenyl silicone rubber, molecular weight 500, 7 parts; SiO2 aerogel powder, particle size 250-400 μm, 15 parts; glass microbeads, particle size 40 μm, 30 parts; aluminum silicate fiber, length 10 mm, 1 part; aminopropyltriethoxysilane, 5 parts; HY-512, 5 parts; ethyl acetate, 115 parts.

[0035] The component materials were weighed according to the above proportions, and the hollow glass microspheres and SiO2 aerogel powder were respectively placed in a 30wt% KH-560 acetone solution and soaked for 24 hours. The solution was filtered to remove the solution and then dried. Phenylene silicone resin was dissolved in toluene to prepare a 50wt% solution, aminopropyltrimethoxysilane was added, and the solution was stirred at 60°C for 1 hour. The solvent was removed by reduced pressure distillation to obtain a modified phenylene silicone resin.

[0036] (2) Preparation of aerogel thermal insulation coating Modified phenylene silicone resin and aminopropyl-terminated methylphenyl silicone rubber were added to ethyl acetate, stirred evenly, and then HY-512 was added and stirred thoroughly for 5 minutes; hollow glass microspheres and SiO2 aerogel powder were added and stirred thoroughly for 30 minutes; finally, glass fiber was added and stirred thoroughly for 45 minutes to obtain component A of the aerogel thermal insulation coating; Pentaerythritol tetraacrylate was dissolved in ethyl acetate to prepare a 13.5 wt % pentaerythritol tetraacrylate solution to obtain component B of the aerogel thermal insulation coating.

[0037] (3) Aerogel thermal insulation coating spraying Components A and B were weighed in a 5:1 mass ratio and thoroughly stirred using an electric mixer. The coating was applied using a pneumatic sprayer to a thickness of 1.8 mm and dried at room temperature for 24 hours to obtain an aerogel thermal insulation coating. Its properties are shown in Table 1.

[0038] Example 3 A method for preparing a high-temperature resistant, high-strength, low-thermal-conductivity thermal insulation coating, the specific steps are as follows: (1) Raw material preparation The raw materials used in component A are composed of 100 parts by weight of phenylene silicone resin with a molecular weight of 500; 5 parts of aminopropyl-terminated methylphenyl silicone rubber with a molecular weight of 1500; 40 parts of SiO2 aerogel powder with a particle size of 350-500 μm; 15 parts of glass microbeads with a particle size of 50 μm; 3 parts of mullite fiber with a length of 5 mm; 6 parts of aminopropylmethyldimethoxysilane; 5 parts of MOK-5622; and 115 parts of butanone.

[0039] The component materials were weighed according to the above proportions, and the hollow glass microspheres and SiO2 aerogel powder were respectively placed in a 30wt% KH-560 acetone solution and soaked for 24 hours. The solution was filtered to remove the solution and then dried. Phenylene silicone resin was dissolved in toluene to prepare a 50wt% solution, aminopropylmethyldimethoxysilane was added, and the solution was stirred at 60°C for 1 hour. The solvent was removed by reduced pressure distillation to obtain a modified phenylene silicone resin.

[0040] (3) Aerogel thermal insulation coating spraying Modified phenylene silicone resin and aminopropyl-terminated methylphenyl silicone rubber were added to butanone, stirred evenly, and then MOK-5622 was added and stirred thoroughly for 5 minutes; hollow glass microspheres and SiO2 aerogel powder were added and stirred thoroughly for 30 minutes; finally, mullite fiber was added and stirred thoroughly for 45 minutes to obtain component A of the aerogel thermal insulation coating; The aerogel thermal insulation coating component B was obtained by dissolving isopentamycin tetraacrylate in butanone to prepare an isopentamycin tetraacrylate solution with a concentration of 12 wt %.

[0041] (3) Aerogel thermal insulation coating spraying Components A and B were weighed in a mass ratio of 5:1 and thoroughly stirred using an electric mixer. The coating was sprayed using a pneumatic sprayer to a thickness of 2 mm. After drying at room temperature, the coating was sprayed to a thickness of 2 mm. This was repeated three times, and the coating was dried at room temperature for 24 hours to obtain the aerogel thermal insulation coating. Its properties are shown in Table 1.

[0042] Example 4 A method for preparing a high-temperature resistant, high-strength, low-thermal-conductivity thermal insulation coating, the specific steps are as follows: (1) Raw material preparation The raw materials used in component A are composed of the following by weight: phenylene silicone resin, molecular weight 4500, 100 parts; aminopropyl-terminated methylphenyl silicone rubber, molecular weight 700, 4 parts; SiO2 aerogel powder, particle size 200-350 μm, 30 parts; glass microbeads, particle size 50 μm, 9 parts; glass fiber, length 9 mm, 1.5 parts; quartz fiber, length 5 mm, 1.5 parts; aminopropylmethyldiethoxysilane, 7 parts; BYK-333, 5 parts; tetrahydrofuran, 115 parts.

[0043] The component materials were weighed according to the above proportions, and the hollow glass microspheres and SiO2 aerogel powder were respectively placed in KH-560 acetone solution and soaked for 24 hours. The solution was filtered to remove the solution and then dried. Phenylene silicone resin was dissolved in toluene to prepare a 50wt% solution, and aminopropylmethyldiethoxysilane was added. The solution was stirred and reacted at 60°C for 1 hour. The solvent was removed by reduced pressure distillation to obtain a modified phenylene silicone resin.

[0044] (2) Preparation of aerogel thermal insulation coating Modified phenylene silicone resin and aminopropyl-terminated methylphenyl silicone rubber were added to tetrahydrofuran, stirred evenly, and then BYK-333 was added and stirred thoroughly for 5 minutes; hollow glass microspheres and SiO2 aerogel powder were added and stirred thoroughly for 30 minutes; finally, glass fiber and quartz fiber were added and stirred thoroughly for 45 minutes to obtain component A of the aerogel thermal insulation coating; Pentaerythritol tetraacrylate was dissolved in tetrahydrofuran to prepare a pentaerythritol tetraacrylate solution with a concentration of 15 wt % to obtain component B of the aerogel thermal insulation coating.

[0045] (3) Aerogel thermal insulation coating spraying Components A and B were weighed in a 5:1 mass ratio and thoroughly stirred using an electric mixer. The coating was applied using a pneumatic sprayer to a thickness of 0.7 mm and dried at room temperature for 24 hours to obtain an aerogel thermal insulation coating. Its properties are shown in Table 1.

[0046] Example 5 A method for preparing a high-temperature resistant, high-strength, low-thermal-conductivity thermal insulation coating, the specific steps are as follows: (1) Raw material preparation The raw materials used in component A are composed of the following by weight: phenylene silicone resin, molecular weight 1500, 100 parts; aminopropyl-terminated methylphenyl silicone rubber, molecular weight 1900, 6 parts; SiO2 aerogel powder, particle size 300-450 μm, 27 parts; glass microbeads, particle size 60 μm, 20 parts; quartz fiber, length 6 mm, 2.5 parts; aminopropyltrimethoxysilane, 3.8 parts; MOK-5622, 5 parts; ethyl acetate, 115 parts.

[0047] The component materials were weighed according to the above proportions, and the hollow glass microspheres and SiO2 aerogel powder were respectively placed in KH-560 acetone solution and soaked for 24 hours. The solution was filtered to remove the solution and then dried. Phenylene silicone resin was dissolved in toluene to prepare a 50wt% solution, aminopropyltrimethoxysilane was added, and the solution was stirred at 60°C for 1 hour. The solvent was removed by reduced pressure distillation to obtain a modified phenylene silicone resin.

[0048] (2) Preparation of aerogel thermal insulation coating Modified phenylene silicone resin and aminopropyl-terminated methylphenyl silicone rubber were added to ethyl acetate, stirred evenly, and then MOK-5622 was added and stirred thoroughly for 5 minutes; hollow glass microspheres and SiO2 aerogel powder were added and stirred thoroughly for 30 minutes; finally, quartz fiber was added and stirred thoroughly for 45 minutes to obtain component A of the aerogel thermal insulation coating; Pentaerythritol tetraacrylate was dissolved in ethyl acetate to prepare a pentaerythritol tetraacrylate solution with a concentration of 14.8 wt % to obtain component B of the aerogel thermal insulation coating.

[0049] (3) Aerogel thermal insulation coating spraying Components A and B were weighed in a mass ratio of 5:1 and thoroughly stirred using an electric mixer. The coating was sprayed using a pneumatic sprayer to a thickness of 1.5 mm. After drying at room temperature, the coating was sprayed to an additional 1.5 mm thickness. This was repeated four times. Finally, the coating was dried at room temperature for 24 hours to obtain the aerogel thermal insulation coating. Its properties are shown in Table 1.

[0050] Comparative Example A method for preparing an aerogel thermal insulation coating, the specific steps are as follows: (1) Raw material preparation The raw material composition is calculated as follows by weight: acrylic emulsion, 100 parts; SiO2 aerogel powder, with a particle size of 150 to 300 μm, 20 parts; glass microbeads, with a particle size of 60 μm, 25 parts; MOK-5622, 5 parts, and deionized water, 20 parts.

[0051] (2) Preparation of aerogel thermal insulation coating Weigh the components according to the above proportions, add deionized water to the acrylic emulsion, stir evenly, then add MOK-5622 and stir thoroughly for 5 minutes; add hollow glass microspheres and SiO2 aerogel powder and stir thoroughly for 30 minutes to obtain the aerogel thermal insulation coating.

[0052] (3) Aerogel thermal insulation coating spraying The aerogel thermal insulation coating was fully stirred with an electric stirrer, and the coating was sprayed with a pneumatic sprayer to a thickness of 2 mm. The aerogel thermal insulation coating was dried at room temperature for 24 h to obtain the aerogel thermal insulation coating. The properties of the aerogel thermal insulation coating are shown in Table 1.

[0053] Experimental example: Aerogel thermal insulation coating performance test The density, thermal conductivity, and temperature resistance of the aerogel thermal insulation coatings prepared in the above-mentioned embodiments and comparative examples were tested. The density was tested according to GB / T 533-2008; the thermal conductivity was tested according to GB / T 10295-2008; and the temperature resistance was tested using a muffle furnace. The coating sample was placed in a muffle furnace at a specific temperature and the temperature was kept constant. After a certain period of time, the sample was removed and its condition was observed. Specific performance test results are shown in Table 1. Figure 1 and 2 .

[0054] Table 1 Test items Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example <![CDATA[Density / (g / cm 3 )]]> 0.32 0.38 0.23 0.46 0.35 0.29 Thermal conductivity at room temperature / (W / m·k) 0.031 0.029 0.025 0.027 0.027 0.035 Bake at 300℃ for 30 minutes No change No change No change No change No change Surface cracking and peeling Bake at 350℃ for 15 minutes No change No change No change No change No change Surface cracking and peeling As can be seen from Table 1, using phenylene silicone resin as the coating film-forming substrate can effectively increase the operating temperature of the aerogel thermal insulation coating. At the same time, surface modification of the hollow glass microspheres and aerogel powder effectively improves the dispersion uniformity of the thermal insulation filler and increases the allowable usage of the thermal insulation filler, giving the aerogel thermal insulation coating a superior thermal insulation effect. The high-temperature-resistant, high-strength, low-thermal conductivity thermal insulation coating obtained in this application can be used for long periods of time in high-temperature environments of 300°C-350°C, providing a high-performance thermal insulation coating for high-temperature applications such as missile weapons, ship equipment, industrial kilns, and chemical pipelines.

[0055] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A high temperature resistant, high strength and low thermal conductivity thermal insulation coating, characterized in that: The raw material composition is calculated by weight: The thermal insulation coating is divided into two components, A and B, wherein the composition of component A is: silicone resin, 100 parts; aerogel powder, 15-40 parts; glass microspheres, 9-30 parts; reinforcing fiber, 1-3 parts; modifier, 3-7 parts; toughening agent, 3-7 parts; dispersant, 2-5 parts; diluent, 70-115 parts; Component B is a cross-linking agent. When using, mix components A and B in a mass ratio of 5:1 and spray them.

2. The high-temperature resistant, high-strength, low-thermal-conductivity thermal insulation coating according to claim 1, characterized in that: The organic silicone resin is phenylene organic silicone resin with a molecular weight Mw of 500-6000; the toughening agent is aminopropyl-terminated methylphenyl silicone rubber with a molecular weight Mw of 500-2000.

3. The high-temperature resistant, high-strength, low-thermal-conductivity thermal insulation coating according to claim 1, characterized in that: The aerogel powder is SiO2 aerogel powder with a particle size of 150 to 500 μm; the glass microspheres are hollow glass microspheres with a particle size of 40 to 60 μm.

4. The high-temperature resistant, high-strength, low-thermal-conductivity thermal insulation coating according to claim 1, characterized in that: The reinforcing fiber is one of glass fiber, quartz fiber, aluminum silicate fiber and mullite fiber or a mixture of two thereof; the length of the fiber is 5 to 10 mm.

5. The high-temperature resistant, high-strength, low-thermal-conductivity thermal insulation coating according to claim 1, characterized in that: The modifier is one of aminopropyltrimethoxysilane, aminopropyltriethoxysilane, aminopropylmethyldimethoxysilane and aminopropylmethyldiethoxysilane.

6. The high-temperature resistant, high-strength, low-thermal-conductivity thermal insulation coating according to claim 1, characterized in that: The dispersant is one of BYK-333, HY-512, and MOK-5622; and the diluent is one of butanone, ethyl acetate, and tetrahydrofuran.

7. The high-temperature resistant, high-strength, low-thermal-conductivity thermal insulation coating according to claim 1, characterized in that: The crosslinking agent of component B is a solution of isopentaerythritol tetraacrylate, and the solvent used is the same as the diluent in component A, with a mass fraction of 10-15%.

8. The high-temperature resistant, high-strength, low-thermal-conductivity thermal insulation coating according to any one of claims 1 to 7, characterized in that: The final coating density was 0.2 g / cm 3 ~0.5g / cm 3 , bonding strength ≥ 0.5MPa, room temperature thermal conductivity ≤ 0.035W / m·k, 300℃ thermal conductivity ≤ 0.06W / m·k.

9. The method for preparing the high-temperature resistant, high-strength, low-thermal-conductivity thermal insulation coating according to any one of claims 1 to 8, characterized in that: The steps include: (1) Raw material preparation Weigh each raw material according to the ratio. Glass microspheres and aerogel powder are each soaked in a 30wt% KH-560 acetone solution for at least 24 hours. The solution is then filtered to remove the solution, and the powder is air-dried for later use. The silicone resin is first dissolved in toluene to prepare a 50wt% solution. The modifier is then added and stirred at 60°C for 1 hour. The solvent is then removed by vacuum distillation to obtain the modified silicone resin. (2) Preparation of aerogel thermal insulation coating The modified silicone resin and toughening agent are added to the diluent, stirred evenly, and then a dispersant is added and stirred thoroughly for 5 minutes; glass microspheres and aerogel powder are added and stirred thoroughly for 30 minutes; finally, reinforcing fibers are added and stirred thoroughly for 45 minutes to obtain component A of the aerogel thermal insulation coating; The isopentacryl tetraacrylate and the same solvent as the diluent in the A component are prepared into an isopentacryl tetraacrylate solution to obtain the aerogel thermal insulation coating component B; (3) Aerogel thermal insulation coating spraying Component A and component B were weighed respectively in a mass ratio of 5:1, and were fully stirred with a mixer; the coating was sprayed with a sprayer, and after spraying to a specified thickness, it was dried in a natural environment at room temperature for 24 hours to obtain an aerogel thermal insulation coating.

10. The method for preparing a high-temperature resistant, high-strength, low-thermal-conductivity thermal insulation coating according to claim 9, characterized in that: The thickness of a single spray shall not exceed 2mm, and the total thickness of multiple sprays shall not exceed 8mm; when spraying multiple times, the next spraying shall be carried out after the surface of the coating after one spraying is dry.

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