A method for preparing insulating thermally conductive silicone coating

Abstract

The present invention relates to the technical field of organic silicon coatings, and discloses a method for preparing an insulating heat-conducting organic silicon coating, wherein the present invention uses N-(3-aminopropyl)acetamide, methacrylate-2-(perfluorooctyl)ethyl ester, (3-glycidoxypropyl)methyldiethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, glacial acetic acid, and modified silicon carbide as raw materials, and uses N-(3-aminopropyl)acetamide and methacrylate-2-(perfluorooctyl)ethyl ester to prepare intermediate 1, and prepares intermediate 2 by hydrolysis reaction, and then prepares intermediate 3 by ring-opening reaction with (3-glycidoxypropyl)methyldiethoxysilane, and finally prepares fluorinated organic silicon by co-hydrolysis-polycondensation method, and then mixes with modified silicon carbide to prepare insulating heat-conducting organic silicon coating. The insulating heat-conducting organic silicon coating prepared by the present invention has good insulation, flexibility, excellent thermal conductivity and corrosion resistance.

Description

Technical Field

[0001] The invention relates to the technical field of organic silicon coatings, in particular to a method for preparing an insulating and heat-conductive organic silicon coating. Background Art

[0002] Organic silicon coating is a coating with organic silicon polymer or its modified polymer as the main film-forming substance. This coating has many excellent properties, including heat and cold resistance, electrical insulation, corona resistance, radiation resistance, moisture resistance and water repellency, weather resistance, stain resistance and chemical corrosion resistance. These properties make organic silicon coatings stable in high and low temperature environments and have excellent gloss and color retention properties.

[0003] Silicone coatings are widely used in many fields, including defense industry, electrical industry, petrochemical industry, aerospace, rail transportation, etc. Especially, they are widely used in equipment under high temperature and corrosive media, such as furnace parts, steel component surfaces, and aircraft engine parts.

[0004] For example, the patent with the authorization announcement number WO2017024693A1 discloses an organosilicon coating, which uses methyl vinyl organosilicon polymer, 1-methylphenyl organosilicon polymer, hydrogenated silicone oil, fluorinated acrylate monomer, silicon dioxide, etc. as raw materials. An organosilicon coating is prepared, which has good adhesion to silicone rubber or fluororubber substrates that have not been surface treated, but the coating cannot be used in humid or highly corrosive environments, and its corrosion resistance is poor. Summary of the invention

[0005] 1. Technical issues to be resolved

[0006] In view of the deficiencies of the prior art, the present invention provides a method for preparing an insulating thermally conductive organic silicon coating. The prepared insulating thermally conductive organic silicon coating has good corrosion resistance and thermal conductivity.

[0007] (II) Technical solution

[0008] A method for preparing an insulating thermally conductive silicone coating, the preparation method being as follows:

[0009] Add modified silicon carbide and fluorinated silicone to tetrahydrofuran solvent, stir and mix evenly for 20-40 minutes, add dispersant (BYK-161), wetting agent (BYK-405) and leveling agent (BYK-306), stir for 10-30 minutes to obtain insulating thermal conductive silicone coating.

[0010] Preferably, the preparation method of the fluorine-containing organosilicon is as follows:

[0011] (1) Add N-(3-aminopropyl)acetamide to toluene solvent, heat to 20-30°C, stir and mix evenly, add 2-(perfluorooctyl)ethyl methacrylate at a rate of 30-50 drops / min, and after the addition is complete, heat to 50-70°C, let stand for 1-3 hours, and distill under reduced pressure to obtain intermediate 1;

[0012] (2) Add intermediate 1 to ethanol, stir and mix, then add 37.5% concentrated hydrochloric acid solution, heat to 75-85°C, react for 11-13h, distill under reduced pressure, add caustic soda to neutralize, extract with petroleum ether, wash with deionized water, dry with anhydrous sodium sulfate, filter and concentrate to obtain intermediate 2;

[0013] (3) Add intermediate 2, (3-glycidoxypropyl)methyldiethoxysilane to toluene solvent, raise the temperature to 70-90°C, stir for 10-14h, and distill under reduced pressure to obtain intermediate 3;

[0014] (4) Add intermediate 3, methyltriethoxysilane, dimethyldiethoxysilane and glacial acetic acid to tetrahydrofuran solvent, stir and mix evenly, raise the temperature to 60-70°C, react for 22-26 hours, cool to room temperature, distill under reduced pressure, add ethyl acetate, wash with deionized water, dry with anhydrous sodium sulfate, and distill under reduced pressure to obtain fluorinated organosilicon.

[0015] Preferably, in step (1), the mass ratio of N-(3-aminopropyl)acetamide to 2-(perfluorooctyl)ethyl methacrylate is 1:2.3-3.

[0016] Preferably, in step (3), the mass ratio of intermediate 2 to (3-glycidoxypropyl)methyldiethoxysilane is 1:0.327-0.491.

[0017] Preferably, in step (4), the mass ratio of intermediate 3, methyltriethoxysilane, dimethyldiethoxysilane, glacial acetic acid and ethyl acetate is 1:0.583-0.624:0.078-0.095:0.003-0.004:0.041-0.062.

[0018] Preferably, the amounts of the dispersant, lubricant and leveling agent used account for 1-3%, 1-4.6% and 0.9-3.4% of the total mass of the fluorinated organosilicon and the modified silicon carbide, respectively.

[0019] Preferably, the mass ratio of modified silicon carbide to fluorine-containing organosilicon is 0.1-0.3:1.

[0020] Preferably, the modified silicon carbide preparation method is as follows:

[0021] Add caustic soda to anhydrous ethanol, adjust the pH to 12.0, then add silicon carbide, then add silane coupling agent KH570, heat to 70°C, stir and react for 6 hours, vacuum filter, wash with deionized water until neutral, and dry to obtain modified silicon carbide.

[0022] Preferably, the mass ratio of KH570 to silicon carbide is 0.02-0.05:1.

[0023] 3. Beneficial technical effects

[0024] The invention uses N-(3-aminopropyl)acetamide, 2-(perfluorooctyl)ethyl methacrylate, (3-glycidoxypropyl)methyldiethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, glacial acetic acid and modified silicon carbide as raw materials, uses N-(3-aminopropyl)acetamide and 2-(perfluorooctyl)ethyl methacrylate to prepare intermediate 1, and then prepares intermediate 2 through hydrolysis reaction, and then prepares intermediate 3 through ring-opening reaction with (3-glycidoxypropyl)methyldiethoxysilane, and finally prepares fluorinated organic silicon through co-hydrolysis-polycondensation method, and then mixes with modified silicon carbide to prepare insulating thermal conductive organic silicon coating. The preparation method is simple and the structure is novel.

[0025] The insulating heat-conductive organic silicon coating prepared by the present invention contains fluorinated groups, alkyl groups and siloxy groups. The bond energy of the C—F bond in the fluorinated groups is strong and the breakdown field strength is high. At the same time, the fluorinated groups absorb electrons and form a charge shielding layer on the surface of the material, which plays a role in preventing incident electrons from bombarding the material. The alkyl group is a non-polar group and can effectively isolate the conductive group. The Si-O bond in the siloxy group has a high bond energy, so that the chemical property is stable and it is not easy to react with other chemical substances, so as to maintain good insulation performance. At the same time, the molecular structure of the group is relatively non-polar, which reduces the generation of free charges and reduces the conductivity.

[0026] The fluorinated groups in the insulating thermally conductive silicone coating prepared by the present invention have high chemical stability and can resist corrosion from a variety of chemical substances such as acids, alkalis and oxidants, thereby improving the corrosion resistance of the present invention. The fluorinated groups are long-chain groups, which can effectively absorb and disperse externally applied stress and reduce brittleness. At the same time, the van der Waals forces generated between the long-chain groups can improve the overall strength and toughness of the material and reduce the tendency to fracture.

[0027] The insulating thermally conductive silicone coating prepared by the present invention contains modified silicon carbide, which has a hexagonal crystal structure and a dense arrangement of atoms, which is conducive to the effective conduction of heat. At the same time, silicon carbide can obtain fewer crystal defects and impurities during the synthesis process, which is conducive to reducing thermal resistance and improving thermal conductivity. Silicon carbide has good insulation properties. The insulating thermally conductive silicone coating prepared by the present invention has good insulation properties, excellent thermal conductivity and corrosion resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a preparation route for fluorinated silicone. DETAILED DESCRIPTION

[0029] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Embodiment 1

[0030] (1) Add 11.6 g of N-(3-aminopropyl)acetamide to 100 ml of toluene solvent, heat to 30°C, stir and mix evenly, add 26.6 g of 2-(perfluorooctyl)ethyl methacrylate, and add dropwise at a rate of 50 drops / min. After the addition is complete, heat to 50°C, let stand for 1 hour, and distill under reduced pressure to obtain intermediate 1;

[0031] (2) Add 64.8 g of intermediate 1 to 100 ml of ethanol solvent, stir and mix, then add 6.84 g of 37.5% concentrated hydrochloric acid solution, heat to reflux, react for 13 h, distill under reduced pressure, add caustic soda to neutralize, extract with petroleum ether, wash with deionized water, dry with anhydrous sodium sulfate, filter and concentrate to obtain intermediate 2;

[0032] (3) Add 60.6 g of intermediate 2 and 24.8 g of (3-glycidoxypropyl)methyldiethoxysilane to 150 ml of toluene solvent, heat to 90 °C, stir for 14 h, and distill under reduced pressure to obtain intermediate 3;

[0033] (4) Add 85.47 g of intermediate 3, 49.84 g of methyltriethoxysilane, 7.4 g of dimethyldiethoxysilane and 0.36 g of glacial acetic acid into 200 ml of tetrahydrofuran solvent, stir and mix evenly, raise the temperature to reflux, react for 26 h, cool to room temperature, distill under reduced pressure, add 4.4 g of ethyl acetate, wash with deionized water, dry over anhydrous sodium sulfate, and distill under reduced pressure to obtain fluorinated organosilicon.

[0034] (5) Add caustic soda to 100 g of anhydrous ethanol, adjust the pH to 12.0, then add 10 g of silicon carbide, then add 0.2 g of silane coupling agent (KH570), raise the temperature to 70°C, stir and react for 6 h, vacuum filter, wash with deionized water until neutral, and dry to obtain modified silicon carbide.

[0035] (6) Add 3 g of modified silicon carbide and 10 g of fluorinated silicone into 50 ml of tetrahydrofuran solvent, stir and mix evenly for 40 min, add 0.285 g of dispersant, 0.57 g of wetting agent and 0.1855 g of leveling agent, stir for 30 min, and obtain an insulating thermally conductive silicone coating. Embodiment 2

[0036] (1) Add 11.6 g of N-(3-aminopropyl)acetamide to 100 ml of toluene solvent, heat to 20°C, stir and mix evenly, add 31.92 g of 2-(perfluorooctyl)ethyl methacrylate, and add at a rate of 30 drops / min. After the addition is complete, heat to 70°C, let react for 3 h, and distill under reduced pressure to obtain intermediate 1;

[0037] (2) Add 64.8 g of intermediate 1 to 150 ml of ethanol solvent, stir and mix, then add 6.84 g of 37.5% concentrated hydrochloric acid solution, heat to reflux, react for 11 h, distill under reduced pressure, add caustic soda to neutralize, extract with petroleum ether, wash with deionized water, dry with anhydrous sodium sulfate, filter and concentrate to obtain intermediate 2;

[0038] (3) Add 60.6 g of intermediate 2 and 19.84 g of (3-glycidoxypropyl)methyldiethoxysilane to 150 ml of toluene solvent, heat to 80 °C, stir for 10 h, and distill under reduced pressure to obtain intermediate 3;

[0039] (4) Add 84.47 g of intermediate 3, 53.4 g of methyltriethoxysilane, 6.66 g of dimethyldiethoxysilane, and 0.24 g of glacial acetic acid to 200 ml of tetrahydrofuran solvent, stir and mix evenly, raise the temperature to reflux, react for 22 h, cool to room temperature, distill under reduced pressure, add 5.28 g of ethyl acetate, wash with deionized water, dry over anhydrous sodium sulfate, and distill under reduced pressure to obtain fluorinated organosilicon;

[0040] (5) Add caustic soda to 100 g of anhydrous ethanol, adjust the pH to 12.0, then add 10 g of silicon carbide, then add 0.2 g of silane coupling agent (KH570), raise the temperature to 70°C, stir and react for 6 h, vacuum filter, wash with deionized water until neutral, and dry to obtain modified silicon carbide.

[0041] (6) Add 1 g of modified silicon carbide and 10 g of fluorinated silicone into 100 ml of tetrahydrofuran solvent, stir and mix evenly for 20 min, add 0.15 g of dispersant, 0.5 g of wetting agent and 0.1 g of leveling agent, stir for 10 min, and obtain an insulating thermally conductive silicone coating. Embodiment 3

[0042] (1) Add 11.6 g of N-(3-aminopropyl)acetamide to 100 ml of toluene solvent, heat to 25 °C, stir and mix evenly, add 37.24 g of 2-(perfluorooctyl)ethyl methacrylate, and add dropwise at a rate of 40 drops / min. After the addition is complete, heat to 60 °C, let stand for 2 h, and distill under reduced pressure to obtain intermediate 1;

[0043] (2) Add 64.8 g of intermediate 1 to 150 ml of ethanol solvent, stir and mix, then add 6.84 g of 37.5% concentrated hydrochloric acid solution, heat to reflux, react for 12 h, distill under reduced pressure, add caustic soda to neutralize, extract with petroleum ether, wash with deionized water, dry with anhydrous sodium sulfate, filter and concentrate to obtain intermediate 2;

[0044] (3) Add 60.6 g of intermediate 2 and 29.76 g of (3-glycidoxypropyl)methyldiethoxysilane to 150 ml of tetrahydrofuran solvent, heat to 70°C, stir for 12 h, and distill under reduced pressure to obtain intermediate 3;

[0045] (4) Add 85.47 g of intermediate 3, 51.62 g of methyltriethoxysilane, 8.14 g of dimethyldiethoxysilane, and 0.36 g of glacial acetic acid into 200 ml of tetrahydrofuran solvent, stir and mix evenly, raise the temperature to reflux, react for 25 h, cool to room temperature, distill under reduced pressure, add 3.52 g of ethyl acetate, wash with deionized water, dry over anhydrous sodium sulfate, and distill under reduced pressure to obtain fluorinated organosilicon;

[0046] (5) Add caustic soda to 100 g of anhydrous ethanol, adjust the pH to 12.0, then add 10 g of silicon carbide, then add 0.2 g of silane coupling agent (KH570), raise the temperature to 70°C, stir and react for 6 h, vacuum filter, wash with deionized water until neutral, and dry to obtain modified silicon carbide.

[0047] (6) Add 2 g of modified silicon carbide and 10 g of fluorinated silicone into tetrahydrofuran solvent, stir and mix evenly for 40 min, add 0.18 g of dispersant, 0.12 g of wetting agent and 0.4 g of leveling agent, stir for 20 min, and obtain an insulating thermally conductive silicone coating.

[0048] Comparative Example 1

[0049] The difference between this comparative example and Example 2 is that intermediate 3 is not contained in step (4).

[0050] Comparative Example 2

[0051] Add 10 g of SH-3021 silicone resin to 50 ml of tetrahydrofuran solvent, stir and mix evenly, stir for 40 minutes, add 0.285 g of dispersant, 0.57 g of wetting agent and 0.1855 g of leveling agent, stir for 30 minutes to obtain silicone coating.

[0052] After cleaning the surface of the carbon steel sheet, polish it with 300 mesh water-resistant sandpaper until there is no rust on the surface, then finely polish it with 500 mesh water-resistant sandpaper, sandblast and polish, clean it with deionized water, soak it in a 3-5% sodium hydroxide solution, heat it to 80°C, keep it warm for 20 minutes, ultrasonically clean it for 5 minutes, clean it with deionized water until it is neutral, dry it for 15 minutes, coat it with tetrahydrofuran solvent, and dry it for another 15 minutes. Then take 10g of silicone resin and apply it to the surface of the substrate with a nylon fine brush, dry it at room temperature for 12 hours, heat it in a muffle furnace to 300°C, and the heating rate is 5°C / min. Curing heat treatment is performed for 120 minutes, and it is cooled to room temperature and taken out to obtain a silicone coating.

[0053] Insulation performance test:

[0054] The dielectric constant of the coating was analyzed using the E4991A dielectric constant analyzer from Agilent Technologies Singapore. If the dielectric constant is less than 6, it can meet the insulation requirements.

[0055] Table 1: Test results of dielectric constants of various embodiments and comparative examples

[0056]

[0057] As can be seen from Table 1, the dielectric constants of Examples 1-3 and Comparative Examples 1-2 are all less than 6, and both meet the insulation requirements. The reason why the dielectric constants of Examples 1-3 and Comparative Example 1 are higher than those of Comparative Example 2 is that they contain fluorinated groups and filler silicon carbide. The energy band structure of silicon carbide enables it to have a high energy gap, so that it can withstand high electric fields without conductivity. The larger energy gap helps to inhibit the generation of carriers. At the same time, high-quality silicon carbide crystals usually have a lower defect density. The low defect density ensures a low recombination rate of electrons and holes, reducing conductivity. The fluorinated groups have a very high resistivity and can effectively prevent the free flow of electrons, thereby preventing the conduction of current, thereby improving insulation. The dielectric constant of Comparative Example 1 is higher than that of Comparative Example 2. The reason is that Comparative Example 1 contains silicon carbide, and the organic silicon coating prepared by the present invention has good insulation properties.

[0058] Thermal conductivity test: The thermal conductivity of the silicone coating samples prepared in Examples 1-3 and Comparative Examples 1-3 was tested using a TPS2200 thermal constant analyzer produced by HotDiSk, Sweden.

[0059] Table 2: Test results of thermal conductivity of various embodiments and comparative examples

[0060]

[0061] As can be seen from Table 2, the thermal conductivity of Comparative Example 2 is smaller than that of other embodiments, so its thermal conductivity is poor, because Examples 1-3 and Comparative Example 1 all contain silicon carbide filler. The reason is that the cubic or hexagonal crystal structure of silicon carbide makes the bonding force between atoms stronger, resulting in it being able to effectively transfer heat energy during heat conduction. This tight atomic arrangement helps to reduce phonon scattering, thereby improving thermal conductivity. At the same time, the silicon carbide content in Examples 1-3 is in the following order from large to small: Example 1> Example 3> Example 2. As can be seen from Table 2, as the content of silicon carbide increases, its thermal conductivity increases. The reason is that as the amount of filler increases, more filler particles will be dispersed between the silicone resin molecular chains, and its weakening effect on the intermolecular forces of silicone is enhanced, which is more conducive to achieving uniform distribution of filler particles in the silicone matrix. On this basis, as the number of added filler particles gradually increases, the effective contact between the fillers increases, and the probability and ability of forming a heat-conducting path in the silicone resin matrix will gradually increase. The thermal conductivity of Example 2 is lower than that of Comparative Example 1. The reason is that fluorine atoms, due to their larger electronegativity, can form strong covalent bonds, making the crystal structure of the material more stable, and the propagation of thermal vibrations is inhibited, thereby reducing the heat conduction efficiency.

[0062] Corrosion testing:

[0063] Electrochemical test: The instrument used for the electrochemical test in this work was a CHI660E electrochemical workstation from Shanghai Chenhua Instrument Co., Ltd. The electrolyte was a 3.5% NaCl solution. The working area of ​​the samples of Examples 1-3 and Comparative Examples 1-3 was 1.95 cm 2 , the sample thickness is 150μm±10μm, the scanning range is 100KHz-100mHz, the sinusoidal interference is ±0.5V, and the ZSimpW software package is used to analyze the EIS data. The larger the impedance modulus of the coating, the better the corrosion resistance of the coating.

[0064] Table 3: Test results of impedance modulus of embodiments and comparative examples

[0065]

[0066] As shown in Table 3, the impedance modulus of Comparative Example 1 and Comparative Example 2 is the smallest compared with other embodiments and comparative examples, so the corrosion resistance is poor. Because Examples 1-3 all contain fluorinated groups, the reason is that the fluorinated groups have high chemical stability and can resist corrosion from various chemical substances such as acids, alkalis and oxidants, thereby improving the corrosion resistance of the present invention. The impedance modulus value of Comparative Example 1 is larger than that of Comparative Example 2, because silicon carbide is an inorganic substance, its chemical properties are stable, and it has certain corrosion resistance. Therefore, the present invention has good corrosion resistance.

[0067] Flexibility test:

[0068] The test uses the QCJ paint film impactor produced by Tianjin Lida Material Testing Machine Factory for measurement. During the test, the carbon steel sheet is placed on the impact table, and the horizontal height of the impact load (1kg) is adjusted, starting from the highest 50cm, and the impact test is carried out. If the impact surface is not damaged, the impact resistance is good, and its impact resistance value is 50kg•cm. If damage occurs, the load horizontal height is lowered and the experiment is repeated until the coating surface is not damaged.

[0069] Table 4: Test results of impact resistance of examples and comparative examples

[0070]

[0071] As can be seen from Table 4, the impact resistance of Comparative Example 1-2 is smaller than that of other implementation values, indicating that its flexibility is poor. In contrast, the impact resistance values ​​of the coatings of Examples 1-3 are all 50kg•cm, and no cracks are observed on the surface of the coatings. The reason is that the long-chain fluorinated groups can effectively absorb and disperse the externally applied stress, reduce brittleness, and form van der Waals forces between the long chains, which can improve the strength of the organosilicon coating. Therefore, the introduction of long-chain fluorinated groups can effectively improve the flexibility of the organosilicon coating. The impact resistance value of Comparative Example 1 is greater than that of Comparative Example 2. The reason is that silicon carbide has a hexagonal crystal structure, the atoms are closely arranged, and it has a certain impact resistance.

[0072] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations within the meaning and scope of the equivalent elements of the claims be included in the invention. Any marking in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A method for preparing an insulating thermally conductive silicone coating, characterized in that: The preparation method is as follows: Add modified silicon carbide and fluorine-containing silicone to tetrahydrofuran solvent, stir and mix evenly for 20-40 minutes, add dispersant, wetting agent and leveling agent, stir for 10-30 minutes, and obtain insulating thermal conductive silicone coating; The preparation method of the fluorine-containing organosilicon is as follows: (1) Add N-(3-aminopropyl)acetamide to toluene solvent, heat to 20-30°C, stir and mix evenly, add 2-(perfluorooctyl)ethyl methacrylate at a rate of 30-50 drops / min, and after the addition is complete, heat to 50-70°C, let stand for 1-3 hours, and distill under reduced pressure to obtain intermediate 1; (2) Add intermediate 1 to ethanol, stir and mix, then add 37.5% concentrated hydrochloric acid solution, heat to 75-85°C, react for 11-13h, distill under reduced pressure, add caustic soda to neutralize, extract with petroleum ether, wash with deionized water, dry with anhydrous sodium sulfate, filter and concentrate to obtain intermediate 2; (3) Add intermediate 2, (3-glycidoxypropyl)methyldiethoxysilane to toluene solvent, raise the temperature to 70-90°C, stir for 10-14h, and distill under reduced pressure to obtain intermediate 3; (4) Add intermediate 3, methyltriethoxysilane, dimethyldiethoxysilane and glacial acetic acid to tetrahydrofuran solvent, stir and mix evenly, raise the temperature to 60-70°C, react for 22-26 hours, cool to room temperature, distill under reduced pressure, add ethyl acetate, wash with deionized water, dry with anhydrous sodium sulfate, and distill under reduced pressure to obtain fluorinated organosilicon.

2. The method for preparing the insulating thermally conductive silicone coating according to claim 1, characterized in that: In the step (1), the mass ratio of N-(3-aminopropyl)acetamide to 2-(perfluorooctyl)ethyl methacrylate is 1:2.3-3.

3. The method for preparing the insulating thermally conductive silicone coating according to claim 1, characterized in that: In the step (3), the mass ratio of the intermediate 2 to (3-glycidoxypropyl)methyldiethoxysilane is 1:0.327-0.

491.

4. The method for preparing the insulating thermally conductive silicone coating according to claim 1, characterized in that: In the step (4), the mass ratio of the intermediate 3, methyltriethoxysilane, dimethyldiethoxysilane, glacial acetic acid, and ethyl acetate is 1:0.583-0.624:0.078-0.095:0.003-0.004:0.041-0.

062.

5. The method for preparing the insulating thermally conductive silicone coating according to claim 1, characterized in that: The dosage of dispersant, wetting agent and leveling agent accounts for 1-3%, 1-4.6% and 0.9-3.4% of the total mass of fluorinated organosilicon and modified silicon carbide respectively.

6. The method for preparing the insulating thermally conductive silicone coating according to claim 1, characterized in that: The mass ratio of modified silicon carbide to fluorine-containing organic silicon is 0.1-0.3:

1.

7. The method for preparing the insulating thermally conductive silicone coating according to claim 1, characterized in that: The modified silicon carbide preparation method is as follows: Add caustic soda to anhydrous ethanol, adjust the pH to 12.0, then add silicon carbide, then add silane coupling agent KH570, heat to 70°C, stir and react for 6 hours, vacuum filter, wash with deionized water until neutral, and dry to obtain modified silicon carbide.

8. The method for preparing the insulating thermally conductive silicone coating according to claim 7, characterized in that: The mass ratio of KH570 and silicon carbide is 0.02-0.05:1.

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