Thermal barrier coating and method of making the same

Abstract

This invention relates to the field of coating preparation technology and discloses a heat-insulating coating comprising: 15-35 parts of rosin-based derivative, 10-25 parts of auxiliary heat-insulating filler, 8-18 parts of film-forming agent, 1-5 parts of dispersant, 0.5-3 parts of wetting agent, 0.3-2 parts of defoamer, 0.2-2 parts of thickener, 1-4 parts of film-forming aid, and 20-45 parts of deionized water. This invention improves the compatibility of the auxiliary heat-insulating filler through rosin-based maleic anhydride-aminosilane derivative, and forms a three-dimensional cross-linked network through the hydrolysis and condensation of aminosilane, reducing heat loss channels and achieving synergistic heat insulation. The modified derivative has a heat resistance temperature of over 250℃, and the siloxane structure delays aging, ensuring long-term heat insulation performance, thus solving the problems of poor compatibility, insufficient heat resistance, and easy attenuation of heat insulation in existing coatings.

Description

Technical Field

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

[0002] Thermal insulation coatings, as a highly efficient and convenient thermal insulation and protection material, can effectively block heat transfer and reduce energy consumption, and have broad application prospects in building energy conservation, industrial equipment insulation, and spacecraft thermal protection. Currently, commercially available thermal insulation coatings mainly use organic polymers and inorganic fillers (such as silica, alumina, and hollow glass microspheres) as their core insulation components. However, they have many shortcomings: organic polymer thermal insulation materials have poor heat resistance and are prone to aging and yellowing with long-term use, resulting in significant degradation of their thermal insulation performance; while inorganic filler-based thermal insulation coatings have better heat resistance, their thermal insulation efficiency is limited, and the coating system has poor compatibility, easily leading to delamination, peeling, and other problems, resulting in poor application performance.

[0003] Rosin is a natural renewable resource with abundant reserves in my country, with an annual output of over 600,000 tons. Its main component, resin acid, has a unique tricyclic phenanthrene skeleton structure containing one carboxyl group and two double bonds. This special structure endows rosin with excellent chemical reactivity and thermal stability, making it a high-quality raw material for the preparation of functional materials. However, unmodified rosin has inherent defects such as easy oxidation, easy crystallization, and dark color, which limit its application in the field of high-end thermal insulation coatings. By modifying the molecular structure of rosin through chemical modification and introducing functional groups with thermal insulation functions, rosin-based derivatives can be prepared. This can fully utilize the natural advantages of rosin, solve the shortcomings of existing thermal insulation coatings, achieve high-value-added utilization of natural resources, and align with the trend of green and environmentally friendly development.

[0004] While there are existing reports on the use of rosin in coating preparation, it is mostly used as a film-forming agent or thickener, rather than as a core thermal insulation component. Furthermore, the structural characteristics of rosin are not precisely modified to enhance its thermal insulation performance, resulting in poor insulation effects that fail to meet the thermal insulation requirements of high-end applications. Therefore, developing a thermal insulation coating with modified rosin-based derivatives as the core thermal insulation component, possessing excellent thermal insulation performance, heat resistance, compatibility, and application properties, has significant practical importance and application value. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the shortcomings of poor performance of heat insulation coatings in the prior art, thereby providing a heat insulation coating and its preparation method, using rosin, a natural product, as raw material to improve the heat insulation performance of the heat insulation coating.

[0006] To solve the above-mentioned technical problems, the present invention provides a heat-insulating coating, which, by weight, comprises: 15-35 parts of rosin-based derivative, 10-25 parts of auxiliary heat-insulating filler, 8-18 parts of film-forming agent, 1-5 parts of dispersant, 0.5-3 parts of wetting agent, 0.3-2 parts of defoamer, 0.2-2 parts of thickener, 1-4 parts of film-forming aid, and 20-45 parts of deionized water; The preparation method of the rosin-based derivative includes the following steps: (1) After pulverizing rosin, add it to the reaction vessel, heat it to 120-150℃, stir until completely melted, add hydroquinone as a polymerization inhibitor, the amount of hydroquinone being 0.1-0.3% of the rosin mass, slowly add maleic anhydride, the molar ratio of rosin to maleic anhydride is 1:1.05-1.2, after the addition is complete, keep it at 140-160℃ for 2-4 hours to obtain maleic anhydride modified rosin; (2) Cool the maleic anhydride modified rosin obtained in step (1) to 80-100℃, add xylene as solvent, stir to dissolve, then add an aminosilane coupling agent, wherein the aminosilane coupling agent is N-aminoethyl-γ-aminopropyltrimethoxysilane, the molar ratio of maleic anhydride modified rosin to aminosilane coupling agent is 1:0.8-1.1, add dibutyltin dilaurate as catalyst, wherein the amount of dibutyltin dilaurate is 0.2-0.5% of the mass of maleic anhydride modified rosin, heat to 110-130℃, and reflux for 3-6 hours; (3) After the reaction is complete, the solvent and unreacted impurities are removed by vacuum distillation, cooled to room temperature, and pulverized to obtain rosin-based maleic anhydride-aminosilane.

[0007] Preferably, the auxiliary heat insulation filler includes nano-silica, hollow glass microspheres, and aerogel; Preferably, the nano-silica has a particle size of 20-80 nm, the hollow glass microspheres have a particle size of 50-200 μm, and the aerogel is a silica aerogel with a particle size of 10-50 nm.

[0008] Preferably, the mass ratio of the nano-silica, hollow glass microspheres, and aerogel is 1:2-4:0.5-1.5.

[0009] Preferably, the film-forming agent is at least one of an aqueous acrylic emulsion or an aqueous polyurethane emulsion.

[0010] Preferably, the dispersant is at least one of sodium polyacrylate or polycarboxylate; The wetting agent is at least one of sodium dodecylbenzenesulfonate or fatty alcohol polyoxyethylene ether; The defoamer is at least one of an organosilicon defoamer or a polyether defoamer; The thickener is at least one of hydroxyethyl cellulose or sodium carboxymethyl cellulose; The film-forming aid is at least one of propylene glycol methyl ether acetate or ethylene glycol butyl ether.

[0011] This invention also provides a method for preparing a heat-insulating coating, comprising the following steps: S1: Add deionized water to the mixing tank, turn on the stirring, adjust the speed to 300-500r / min, add the dispersant, wetting agent and defoamer in sequence, stir for 10-20min until the system is uniform and transparent; S2: Keep the stirring speed constant, slowly add rosin-based maleic anhydride-aminosilane and auxiliary heat insulation filler. After the addition is complete, increase the speed to 800-1200 r / min, disperse at high speed for 30-60 min, and then grind with a sand mill to control the particle size of the system after grinding to 20-80 μm to obtain heat insulation slurry. S3: Adjust the rotation speed to 400-600 r / min, add the film-forming agent and film-forming aid to the heat insulation slurry in sequence, stir for 20-30 min to ensure the system is fully mixed; S4: Slowly add the thickener, stir for 10-15 minutes, adjust the viscosity to 2000-5000 mPa·s, then filter to remove impurities and large particles to obtain the heat insulation coating.

[0012] The technical solution of this invention has the following advantages: This invention provides a heat-insulating coating with rosin-based maleic anhydride-aminosilane derivatives as the core heat-insulating component. Through maleic anhydride addition and aminosilane modification of natural rosin, a rigid tricyclic phenanthrene backbone and siloxane groups are introduced into the rosin molecular structure, forming a molecular structure with excellent heat-insulating properties. This structure effectively blocks heat conduction, and its compact packing and weak molecular chain mobility significantly increase the resistance to heat transfer between molecules and reduce the vibrational thermal conductivity. After maleic anhydride addition and aminosilane grafting, stable amide bonds and siloxane groups are introduced into the molecule, synergistically forming a continuous phase with both rigidity and low thermal conductivity. This effectively blocks heat conduction through the coating, resulting in a significant decrease in the overall thermal conductivity of the coating.

[0013] This invention improves the compatibility of auxiliary heat-insulating fillers by using rosin-based maleic anhydride-aminosilane derivatives. The aminosilane hydrolysis and condensation form a three-dimensional cross-linked network, reducing heat loss channels and achieving synergistic heat insulation. The modified derivative has a heat resistance temperature of over 250℃, and the siloxane structure delays aging, ensuring long-term heat insulation performance. This invention solves the problems of poor compatibility, insufficient heat resistance, and easy attenuation of heat insulation in existing coatings. Detailed Implementation

[0014] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0015] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0016] The rosin of this invention uses dehydroabsic acid, and the other raw materials are all commercially available products.

[0017] The particle size of nano-silica is 20-80nm, the particle size of hollow glass microspheres is 50-200μm, and the particle size of silica aerogel is 10-50nm. Example

[0018] A heat-insulating coating, by mass parts, comprises: 150g of rosin-based maleic anhydride-aminosilane derivative, 100g of auxiliary heat-insulating filler (20g of nano-silica, 60g of hollow glass microspheres, 20g of silica aerogel), 80g of water-based acrylic emulsion, 10g of sodium polyacrylate, 5g of sodium dodecylbenzene sulfonate, 3g of organosilicon defoamer, 2g of hydroxyethyl cellulose, 10g of propylene glycol methyl ether acetate, and 450g of deionized water.

[0019] The preparation method of the above-mentioned heat-insulating coating includes the following steps: (1) Preparation of rosin-based maleic anhydride-aminosilane derivatives: ① Add 1 mol of rosin powder to a reaction vessel, heat to 120℃, stir until completely melted, add 0.1% (relative to the mass of rosin) of hydroquinone, slowly add 1.05 mol of maleic anhydride, and after the addition is complete, keep the temperature at 140℃ for 4 hours to obtain maleic anhydride modified rosin. ② Cool the maleic anhydride-modified rosin to 80°C, add xylene and stir to dissolve, then add 0.8 mol N-aminoethyl-γ-aminopropyltrimethoxysilane, add 0.2% (relative to the mass of maleic anhydride-modified rosin) of dibutyltin dilaurate, heat to 110°C, and reflux for 6 hours; ③ Remove the solvent and unreacted impurities by vacuum distillation, cool to room temperature, and pulverize to obtain rosin-based maleic anhydride-aminosilane derivative.

[0020] (2) Preparation of heat-insulating coating: S1: Add 450g of deionized water to the mixing tank, turn on the stirring and adjust the speed to 300r / min. Then add 10g of sodium polyacrylate, 5g of sodium dodecylbenzene sulfonate and 3g of organosilicon defoamer in sequence. Stir for 10min until the system is uniform and transparent. S2: Keep the rotation speed at 300 r / min, slowly add 150 g of rosin-based derivative and 100 g of auxiliary heat insulation filler. After the addition is complete, increase the rotation speed to 800 r / min and disperse at high speed for 60 min. Then grind with a sand mill to control the particle size of the system after grinding to 20-40 μm to obtain the heat insulation slurry. S3: Adjust the rotation speed to 400r / min, add 80g of water-based acrylic emulsion and 10g of propylene glycol methyl ether acetate to the heat insulation slurry, stir for 30min to ensure the system is fully mixed; S4: Slowly add 2g of hydroxyethyl cellulose, stir for 10min, adjust the viscosity of the system to 2000-3000mPa·s (25℃), filter to remove impurities and large particles, and obtain the heat insulation coating. Example

[0021] A heat-insulating coating, by mass parts, comprises: 250g of rosin-based maleic anhydride-aminosilane derivative, 180g of auxiliary heat-insulating filler (40g of nano-silica, 100g of hollow glass microspheres, and 40g of silica aerogel), 130g of waterborne polyurethane emulsion, 30g of polycarboxylate, 15g of fatty alcohol polyoxyethylene ether, 12g of polyether defoamer, 11g of sodium carboxymethyl cellulose, 25g of ethylene glycol butyl ether, and 327g of deionized water.

[0022] The preparation method of the above-mentioned heat-insulating coating includes the following steps: (1) Preparation of rosin-based maleic anhydride-aminosilane derivatives: ① Add 1 mol of rosin powder to a reaction vessel, heat to 135℃, stir until completely melted, add 0.2% (relative to the mass of rosin) of hydroquinone, slowly add 1.1 mol of maleic anhydride, and after the addition is complete, keep the temperature at 150℃ for 3 hours to obtain maleic anhydride modified rosin. ② Cool the maleic anhydride-modified rosin to 90°C, add xylene and stir to dissolve, then add 0.95 mol N-aminoethyl-γ-aminopropyltrimethoxysilane, add 0.35% (relative to the mass of maleic anhydride-modified rosin) of dibutyltin dilaurate, heat to 120°C, and reflux for 4.5 h; ③ Remove the solvent and unreacted impurities by vacuum distillation, cool to room temperature, and pulverize to obtain rosin-based maleic anhydride-aminosilane derivative.

[0023] (2) Preparation of heat-insulating coating: S1: Add 327g of deionized water to the mixing tank, turn on the stirring, adjust the speed to 400r / min, add 30g of polycarboxylate, 15g of fatty alcohol polyoxyethylene ether, and 12g of polyether defoamer in sequence, stir for 15min until the system is uniform and transparent. S2: Keep the rotation speed at 400 r / min, slowly add 250 g of rosin-based derivative and 180 g of auxiliary heat insulation filler. After the addition is complete, increase the rotation speed to 1000 r / min and disperse at high speed for 45 min. Then grind with a sand mill to control the particle size of the system after grinding to 40-60 μm to obtain the heat insulation slurry. S3: Adjust the rotation speed to 500 r / min, add 130 g of waterborne polyurethane emulsion and 25 g of ethylene glycol butyl ether to the heat insulation slurry, stir for 25 min to make the system fully mixed; S4: Slowly add 11g of sodium carboxymethyl cellulose, stir for 12min, adjust the viscosity of the system to 3000-4000mPa·s (25℃), filter to remove impurities and large particles, and obtain the heat insulation coating. Example

[0024] A heat-insulating coating, by weight, comprises: 350g of rosin-based maleic anhydride-aminosilane derivative, 250g of auxiliary heat-insulating filler (50g of nano-silica, 150g of hollow glass microspheres, and 50g of silica aerogel), 180g of a mixture of waterborne acrylic emulsion and waterborne polyurethane emulsion (weight ratio 1:1), 50g of sodium polyacrylate, 30g of fatty alcohol polyoxyethylene ether, 20g of silicone defoamer, 20g of hydroxyethyl cellulose, 40g of propylene glycol methyl ether acetate, and 200g of deionized water.

[0025] The preparation method of the above-mentioned heat-insulating coating includes the following steps: (1) Preparation of rosin-based maleic anhydride-aminosilane derivatives: ① Add 1 mol of rosin powder to a reaction vessel, heat to 150℃, stir until completely melted, add 0.3% (relative to the mass of rosin) of hydroquinone, slowly add 1.2 mol of maleic anhydride, and after the addition is complete, keep the temperature at 160℃ for 2 hours to obtain maleic anhydride modified rosin. ② Cool the maleic anhydride-modified rosin to 100°C, add xylene and stir to dissolve, then add 1.1 mol N-aminoethyl-γ-aminopropyltrimethoxysilane, add 0.5% (relative to the mass of maleic anhydride-modified rosin) of dibutyltin dilaurate, heat to 130°C, and reflux for 3 hours; ③ Remove the solvent and unreacted impurities by vacuum distillation, cool to room temperature, and pulverize to obtain rosin-based maleic anhydride-aminosilane derivative.

[0026] (2) Preparation of heat-insulating coating: S1: Add 200g of deionized water to the mixing tank, turn on the stirring, adjust the speed to 500r / min, add 50g of sodium polyacrylate, 30g of fatty alcohol polyoxyethylene ether, and 20g of silicone defoamer in sequence, stir for 20min until the system is uniform and transparent. S2: Keep the rotation speed at 500 r / min, slowly add 350 g of rosin-based derivative and 250 g of auxiliary heat insulation filler. After the addition is complete, increase the rotation speed to 1200 r / min and disperse at high speed for 30 min. Then grind with a sand mill to control the particle size of the system after grinding to 60-80 μm to obtain the heat insulation slurry. S3: Adjust the rotation speed to 600 r / min, add 180 g of compound film-forming agent (90 g of waterborne acrylic emulsion and 90 g of waterborne polyurethane emulsion) and 40 g of propylene glycol methyl ether acetate to the heat insulation slurry, stir for 20 min to make the system fully mixed; S4: Slowly add 20g of hydroxyethyl cellulose, stir for 15min, adjust the viscosity of the system to 4000-5000mPa·s (25℃), filter to remove impurities and large particles, and obtain the heat insulation coating.

[0027] A common heat-insulating coating, compared with Example 3, does not contain rosin-based maleic anhydride-aminosilane derivatives, but replaces them with hollow glass microspheres of equal mass, while the rest of the composition and preparation method are exactly the same as in Example 3.

[0028] A common heat-insulating coating, compared with Example 3, uses unmodified rosin instead of rosin-based maleic anhydride-aminosilane derivative, while the rest of the composition and preparation method are exactly the same as in Example 3.

[0029] The performance of the heat-insulating coatings prepared in Examples 1-3 and Comparative Examples 1-2 was tested. The test items included: thermal conductivity, solar reflectance, hemispherical emissivity, heat insulation temperature difference, heat resistance, adhesion, and weather resistance. The test methods and standards are as follows: Thermal conductivity: The laser flare method (ISO22007-4) was used with a Netzsch LFA 467 HyperFlash instrument at a temperature of 25℃, with an accuracy of ±3%. Solar reflectance: Ultraviolet-visible-near-infrared spectrophotometer (ASTM E903), referring to GB / T25261-2018 "Reflective Thermal Insulation Coatings for Buildings", using PerkinElmer Lambda 950 instrument, with a test wavelength range of 250~2500nm; Thermal insulation temperature difference: According to GB / T 25261—2018, set different temperatures (50℃, 80℃, 100℃, 120℃, 150℃), and test the temperature difference after the temperature stabilizes; Heat resistance: The coating samples were placed in a constant temperature oven and kept at 150℃, 200℃ and 250℃ for 24 hours respectively. The coating was observed to see if yellowing, cracking or peeling occurred, and the change rate of thermal conductivity of the coating after heat preservation was tested. Adhesion: The adhesion level between the coating and the steel substrate was tested using the cross-cut adhesion test (GB / T 9286-1998). Moisture and heat resistance: After being placed in an environment of 85℃ / 85%RH for 72 hours, observe whether the coating shows signs of blistering or peeling.

[0030]

[0031]

[0032] As shown in Table 1, the thermal conductivity of the heat-insulating coatings prepared in Examples 1-3 of this application is all below 0.032 W / (m·K), with Example 3 having the lowest thermal conductivity at only 0.025 W / (m·K); the solar reflectance is all above 88%; at 150℃, the heat insulation temperature difference of Example 3 reaches 61.2℃, which is 2.03 times that of Comparative Example 1 (30.1℃) and 1.81 times that of Comparative Example 2 (33.8℃); under natural conditions, the heat insulation temperature difference of Example 3 reaches 16.2℃, which is significantly better than the industry standard and the comparative example. This indicates that the rosin-based derivative of this invention, as the core heat-insulating main component, works synergistically with the auxiliary heat-insulating filler to effectively block heat transfer and achieve excellent heat insulation effect.

[0033] After being kept at 150℃, 200℃, and 250℃ for 24 hours, the coatings of Examples 1-3 showed no obvious cracking or peeling, and the change rate of thermal conductivity was less than 8.3%. Among them, the change rate of thermal conductivity of Example 3 at 250℃ was only 6.5%, which was much better than Comparative Examples 1-2. In contrast, Comparative Example 1 cracked and peeled at 250℃, and Comparative Example 2 cracked and peeled severely. This shows that the rosin-based derivative of the present invention has significantly improved heat resistance after modification and can meet the needs of use in high-temperature environments.

[0034] The adhesion grades of the coatings in Examples 1-3 are all below Grade 1, with the adhesion grades of Examples 2-3 being Grade 0, indicating good resistance to damp heat. In contrast, Comparative Examples 1-2 showed blistering or peeling, demonstrating that the coatings of the present invention have good adhesion and resistance to damp heat, and a longer service life.

[0035] Comparative Example 1, without the addition of rosin-based derivatives, used only hollow glass microspheres as the heat insulation filler, and its heat insulation performance and heat resistance were significantly lower than those of the Example. Comparative Example 2 used unmodified rosin, and due to its easy oxidation and poor thermal stability, the heat insulation performance and heat resistance of the coating were also inferior to those of the Example. This further proves that the rosin-based derivatives obtained by modifying rosin with maleic anhydride-aminosilane can significantly improve the overall performance of the coating and solve the shortcomings of the prior art.

[0036] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A heat-insulating coating, characterized in that, By weight, the composition includes: 15-35 parts of rosin-based derivatives, 10-25 parts of auxiliary heat-insulating filler, 8-18 parts of film-forming agent, 1-5 parts of dispersant, 0.5-3 parts of wetting agent, 0.3-2 parts of defoamer, 0.2-2 parts of thickener, 1-4 parts of film-forming aid, and 20-45 parts of deionized water; The preparation method of the rosin-based derivative includes the following steps: (1) After pulverizing rosin, add it to the reaction vessel, heat it to 120-150℃, stir until completely melted, add hydroquinone as a polymerization inhibitor, the amount of hydroquinone being 0.1-0.3% of the rosin mass, slowly add maleic anhydride, the molar ratio of rosin to maleic anhydride is 1:1.05-1.2, after the addition is complete, keep it at 140-160℃ for 2-4 hours to obtain maleic anhydride modified rosin; (2) Cool the maleic anhydride-modified rosin obtained in step (1) to 80-100℃, add xylene as solvent, stir to dissolve, then add an aminosilane coupling agent, wherein the aminosilane coupling agent is N-aminoethyl-γ-aminopropyltrimethoxysilane, and the molar ratio of maleic anhydride-modified rosin to aminosilane coupling agent is 1:0.8-1.

1. Add dibutyltin dilaurate as catalyst, wherein the amount of dibutyltin dilaurate is 0.2-0.5% of the mass of maleic anhydride-modified rosin, heat to 110-130℃, and reflux for 3-6 hours. (3) After the reaction is complete, the solvent and unreacted impurities are removed by vacuum distillation, cooled to room temperature, and pulverized to obtain rosin-based maleic anhydride-aminosilane.

2. The heat-insulating coating according to claim 1, characterized in that, The auxiliary heat insulation filler includes nano-silica, hollow glass microspheres, and aerogel.

3. The heat-insulating coating according to claim 2, characterized in that, The nano-silica has a particle size of 20-80 nm, the hollow glass microspheres have a particle size of 50-200 μm, and the aerogel is a silica aerogel with a particle size of 10-50 nm.

4. The heat-insulating coating according to claim 3, characterized in that, The mass ratio of the nano-silica, hollow glass microspheres, and aerogel is 1:2-4:0.5-1.

5.

5. The heat-insulating coating according to claim 1, characterized in that, The film-forming agent is at least one of an aqueous acrylic emulsion or an aqueous polyurethane emulsion.

6. The heat-insulating coating according to claim 1, characterized in that, The dispersant is at least one of sodium polyacrylate or polycarboxylate; The wetting agent is at least one of sodium dodecylbenzenesulfonate or fatty alcohol polyoxyethylene ether; The defoamer is at least one of an organosilicon defoamer or a polyether defoamer; The thickener is at least one of hydroxyethyl cellulose or sodium carboxymethyl cellulose; The film-forming aid is at least one of propylene glycol methyl ether acetate or ethylene glycol butyl ether.

7. The method for preparing the heat-insulating coating according to any one of claims 1-6, characterized in that, Includes the following steps: S1: Add deionized water to the mixing tank, turn on the stirring, adjust the speed to 300-500r / min, add the dispersant, wetting agent and defoamer in sequence, stir for 10-20min until the system is uniform and transparent; S2: Keep the stirring speed constant, slowly add rosin-based maleic anhydride-aminosilane and auxiliary heat insulation filler. After the addition is complete, increase the speed to 800-1200 r / min, disperse at high speed for 30-60 min, and then grind with a sand mill to control the particle size of the system after grinding to 20-80 μm to obtain heat insulation slurry. S3: Adjust the rotation speed to 400-600 r / min, add the film-forming agent and film-forming aid to the heat insulation slurry in sequence, stir for 20-30 min to ensure the system is fully mixed; S4: Slowly add the thickener, stir for 10-15 minutes, adjust the viscosity to 2000-5000 mPa·s, then filter to remove impurities and large particles to obtain the heat insulation coating.

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