High-temperature-resistant POSS (polyhedral oligomeric silsesquioxane) modified organic silicon ceramic coating and preparation method thereof

Abstract

The invention discloses a high-temperature-resistant POSS (Polyhedral Oligomeric Silsesquioxane) modified organic silicon-ceramic coating and a preparation method thereof. Amino POSS modified organic silicon resin and epoxy modified organic silicon resin are used as base materials, and high-temperature-resistant fillers such as zinc oxide, titanium dioxide, silicon nitride, low-melting-point glass powder and the like, auxiliaries and a solvent are matched, so that the high-temperature-resistant POSS modified organic silicon-ceramic coating is prepared. A paint film is converted into an inorganic ceramic coating from an organic ceramic coating at a high temperature, so that high-temperature protection on a base material is realized. During preparation, all the components are mixed and ground, the mixture is sprayed to a base material and then cured into a film at room temperature, and the formed coating is free of cracking after being subjected to heat preservation for 10 hours at the high temperature of 600 DEG C and is intact after being subjected to cyclic thermal shock for 20 times; the adhesive force is 0 grade at normal temperature and 1 grade after high temperature; no corrosion is generated in a salt spray experiment for 500 hours, and the performance is still stable after acid-base soaking for 72 hours; the flexible cupping depth is greater than or equal to 5mm, and the coating has the advantages of room-temperature curing and convenient construction of an organic silicon coating and the high-temperature resistance of an inorganic ceramic coating, is suitable for protection of high-temperature equipment, and solves the problem that the traditional high-temperature-resistant coating is insufficient in flexibility and temperature resistance.

Description

Technical Field

[0001] The invention relates to the field of coatings, and in particular to a high-temperature resistant POSS modified organosilicon ceramic coating and a preparation method thereof. Background Art

[0002] With the rapid advancement of science and technology, the level of innovation and manufacturing technology in industrial equipment is constantly improving, leading to a growing demand for specialty coatings, such as those that resist high temperatures. Protecting the exterior surfaces of exhaust equipment, chimneys, boiler heat exchanger tubes, heaters, high-temperature reactors, automotive turbocharger oil return line gaskets, and engine cylinder head gaskets, all used in high-temperature environments, is becoming increasingly important. Modern petrochemical, chlor-alkali, chemical fiber, pharmaceutical, and fertilizer production utilizes a wide variety of heat exchangers. In refineries, in particular, these heat exchangers can account for up to 40% of the total weight of process equipment and over 20% of investment. Heat exchangers are primarily constructed of carbon steel, with some also utilizing specialized materials such as stainless steel, copper, titanium, and graphite. Heat exchangers are more susceptible to corrosion than other equipment. This is because in chemical production, process media below 150°C are typically cooled using water circulation. This constant circulation of water leads to continuous evaporation, increasing the concentration of insoluble inorganic salts in the water. This leads to an accumulation of corrosive ions on the heat transfer surfaces of the heat exchanger. This leads to chemical and electrochemical corrosion of the metal surfaces in the complex environment of heat conduction, fluid erosion, material scaling, and medium corrosion, resulting in tube perforation and scaling blockage. As a result, some heat exchangers experience corrosion on their tube sheets after just a few months of operation, with severe rust pits reaching 3-4 mm in diameter. The most economical and feasible solution to this problem is protective coating. The research and development of heat exchanger coatings is a major topic worldwide, especially under high-temperature conditions, where meeting the stringent requirements for acid, alkali, organic solvent, and superheated steam purge resistance is challenging. Therefore, the design of high-temperature-resistant coatings must also consider the coating's mechanical properties, heat resistance, and corrosion resistance before and after high temperatures.

[0003] Silicone heat-resistant coatings have good heat resistance (pure silicone varnish can withstand 200-300°C, and coatings prepared with silicone as the base material and metal powder and appropriate fillers can withstand temperatures below 400°C. Although they have good water resistance, electrical insulation and mechanical properties, they have low hardness and poor flame retardancy. Inorganic high-temperature resistant coatings generally have problems with poor flexibility or poor adhesion. When used as coatings, they can easily cause cracking and peeling of the coating due to differences in thermal expansion coefficients. Polysiloxane resin has become the mainstream high-temperature resistant base resin due to its excellent flexibility and simple room temperature curing method. However, traditional polysiloxane silicone resins generally decompose in large quantities at 500°C due to insufficient -Si-O- bond energy, and lose their protective effect. Therefore, it is very important to further improve the high-temperature resistance of polysiloxane so that it can work for a long time in a temperature range above 500°C.

[0004] Whether it is a fully caged or partially caged silsesquioxane, the silicon atoms and oxygen atoms in its molecules form a cage-like rigid skeleton, and its size is at the nanometer level, which can be regarded as the smallest silica particle. Unlike traditional silica and silicone resins, each silsesquioxane molecule contains organic functional groups. Because of these organic functional groups, its nanostructure has excellent compatibility with polymers, biological systems, and material surfaces. The organic functional groups and Si-O-Si skeleton make POSS an organic-inorganic hybrid material. Due to its special structure, POSS has good compatibility with polymers and can be added to polymers in large quantities to significantly increase the strength and hardness of the polymer. In addition, POSS can also improve the toughness of polymers. The size of POSS molecules is comparable to the microscopic size of material cracks, and it has a certain healing effect on microscopic cracks, thereby terminating the cracks.

[0005] To sum up, the high temperature resistance limit of polysiloxane resin is difficult to exceed 500°C, and the brittleness problem of inorganic fillers has not been effectively solved. How to combine the advantages of organic-inorganic materials to achieve the transformation of "room temperature organic film formation and high temperature inorganic protection" is a technical problem that the industry urgently needs to overcome. Summary of the Invention

[0006] The purpose of the present invention is to provide a high-temperature resistant POSS modified organosilicon ceramic coating and a preparation method thereof. By using organic-inorganic hybrid technology, the coating can achieve long-term temperature resistance of 400-600°C. At the same time, by utilizing a flexible macromolecular structure transition, the brittleness and poor adhesion problems of inorganic fillers are overcome, room temperature curing is achieved, and no high-temperature pretreatment is required. The coating is suitable for coating large components.

[0007] To solve the above technical problems, the technical solution adopted by the present invention is to provide a high-temperature resistant POSS modified silicone ceramic coating, which is based on amino POSS modified silicone and epoxy modified silicone, and is composed of a high-temperature resistant filler, an auxiliary agent and a solvent. The weight ratio of each raw material is:

[0008] Amino POSS modified silicone 10-30%;

[0009] Epoxy modified silicone 5-30%;

[0010] High temperature resistant filler 30-70%;

[0011] The balance is solvent.

[0012] Preferably, an auxiliary agent is further added to the coating, and the auxiliary agent is one or more of a dispersant, a wetting agent, and a defoaming agent, and the amount of the auxiliary agent is ≤5%.

[0013] Preferably, the amino content of the amino POSS modified silicone is 5 to 30%, and the epoxy content of the epoxy modified silicone is 5 to 30%.

[0014] Preferably, the high-temperature resistant filler includes zinc oxide, titanium dioxide, silicon nitride, zirconium oxide, boron nitride, aluminum oxide, chromium oxide, and glass powder, wherein the weight ratio of each component is: zinc oxide 5-15%, titanium dioxide 5-30%, silicon nitride 5-30%, zirconium oxide 5-30%, boron nitride 5-15%, aluminum oxide 5-15%, chromium oxide 5-10%, and glass powder 1-8%.

[0015] Preferably, the solvent is a combination of one or more of xylene, toluene or ethanol.

[0016] Before coating, the surface of the substrate to be sprayed must be sandblasted and rust-removed to the Swedish standard SIS 05-5900Sa2.5 level, or manually rust-removed to the St3 level, and the surface must be kept clean, dry, and free of oil stains. Then, the POSS-modified organic silicon ceramic coating of the present invention is directly applied to the surface of the substrate by brushing or air spraying, and dried at room temperature for about 24 hours to form a high-temperature resistant coating.

[0017] The present invention also provides a method for preparing the POSS modified organosilicon ceramic coating, comprising the following steps:

[0018] (1) preparing an amino POSS modified silicone resin: subjecting amino POSS to a cross-linking reaction with an organosilicon prepolymer under the action of a cross-linking agent and / or a catalyst to obtain an amino POSS modified silicone resin;

[0019] (2) Preparation of epoxy-modified silicone resin: Add 5-30% of the weight of epoxy coupling agent to alkoxysilane monomer, mix evenly, add to anhydrous ethanol, adjust the pH to 3-4 at 60-90°C, add deionized water dropwise, and continue to heat and react for 3-8 hours to obtain epoxy-modified silicone resin;

[0020] (3) Mixing and dispersion: amino POSS modified silicone resin, epoxy modified silicone resin, high temperature resistant filler and solvent are mixed in proportion, and dispersed evenly by high-speed grinding equipment to obtain high temperature resistant POSS modified silicone-ceramic coating.

[0021] Specifically, the organosilicon prepolymer in step (1) is hydroxy silicone oil or hydrogen silicone oil; the crosslinking agent is isocyanate or silane coupling agent; and the catalyst is an organotin compound.

[0022] Specifically, the alkoxysilane monomer described in step (2) is a mixed monomer of ethyl orthosilicate, methyltriethoxysilane, and diethoxydimethylsilane in a molar ratio of (3-7): (1-2): (0.5-1); and the epoxy coupling agent is KH560, KH570 or γ-glycidoxypropyltrimethoxysilane.

[0023] Specifically, the rotation speed of the high-speed grinding equipment is 1500-3000 r / min, and the grinding time is 20-60 minutes.

[0024] The present invention realizes dynamic control of the performance of the coating in different temperature ranges through the synergistic effect of silicone resin and high-temperature resistant filler, and its beneficial effects are:

[0025] 1. At room temperature, the silicone resin, thanks to the flexibility of the -Si-O-Si- backbone and the compatibility of the side chain organic groups, can rapidly cure to form a film, forming an elastic organic protective layer. The coating has strong adhesion to the metal substrate (cross-hatch method ≤ level 1), can adapt to the thermal expansion and contraction of the substrate, and avoids low-temperature cracking, making it suitable for on-site coating of complex-shaped components. At high temperatures, after the side chain organic groups are thermally oxidized and broken, the remaining -Si-O-Si- backbone reacts with the metal oxides (such as ZnO, TiO2) and silicates (such as low-melting-point glass powder) of the high-temperature resistant filler to form a metal-silicon-oxygen network ceramic structure with a temperature resistance of over 600°C. A thin steel plate (50×120×0.45-0.55 mm) coated with the high-temperature resistant coating was tested in a muffle furnace at 600°C for 10 hours, and the coating remained intact with no significant changes.

[0026] 2. The rigid cage-type POSS skeleton is evenly dispersed throughout the coating. When microcracks propagate into the POSS particles, its elastic "cage" structure suppresses cracks by terminating crack tips, inducing crazing / shear banding, and rearranging molecular chains. Experiments have shown that the coating formed by the high-temperature coating of the present invention can withstand five cycles (room temperature to high temperature reciprocating) at temperatures above 400°C without cracking or blistering.

[0027] 3. The ceramic coating formed at high temperature has high density and can resist acid, alkali, organic solvents and high-temperature steam blowing. The hardness reaches 2H at room temperature and increases to 5H after ceramicization at high temperature. The wear resistance is 30% better than that of traditional silicone coatings. By adjusting the ratio of POSS and epoxy-modified silicone, both rigidity (anti-cracking) and flexibility (anti-deformation) can be taken into account to meet the needs of different substrates.

[0028] 4. The coating of the present invention can be directly brushed or sprayed on the surface of the substrate and can be put into use after curing at room temperature without pretreatment of curing by heating. It is particularly suitable for large devices that are inconvenient to paint with traditional heat-resistant coatings. It has good adhesion to metal substrates such as steel, stainless steel, and aluminum, and does not require a primer, which expands the application scenarios (such as engine components, missile launchers, etc.).

[0029] Through the dynamic protection mechanism of "organic film formation → high-temperature ceramicization", the present invention breaks through the bottleneck of the upper temperature resistance limit of silicone coatings and the brittleness of inorganic ceramic coatings, and achieves a multi-dimensional improvement of "convenient coating, high-temperature protection, and mechanical durability", providing a protection solution for the high-temperature industrial field with both technological innovation and engineering practicality. DETAILED DESCRIPTION

[0030] The technical solutions of the present invention are described clearly and completely below with reference to specific embodiments. Obviously, the embodiments described are only a portion of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are also within the scope of protection of the present invention.

[0031] Example 1

[0032] This embodiment provides a high-temperature resistant POSS-modified silicone ceramic coating, which is mixed and dispersed by the following components in percentage by mass: 19% amino POSS-modified silicone resin (amino content is 15%), 11% epoxy-modified silicone resin (epoxy content is 13%), 8% zinc oxide, 10% titanium dioxide, 9% silicon nitride, 12% zirconium oxide, 5% boron nitride, 6% aluminum oxide, 5% chromium oxide, 1% low-melting-point glass powder, and 14% xylene.

[0033] The above components were mixed in proportion, fed into a high-speed grinding device, and ground at a speed of 2000 r / min for 6 hours until they were uniformly dispersed to obtain a high-temperature resistant POSS modified silicone-ceramic coating.

[0034] Before coating, the surface of the substrate to be sprayed is sandblasted to Swedish standard SIS 05-5900Sa2.5 level, or manually rusted to St3 level, and the surface is kept clean, dry, and free of oil stains. Then, the POSS modified silicone ceramic coating of the present invention is directly applied to the surface of the substrate by brushing or air spraying, and dried at room temperature for about 24 hours to form a high-temperature resistant coating.

[0035] Wherein, amino POSS (amino cage-shaped polysilsesquioxane) is synthesized by the following method:

[0036] Add 30g of distilled water, 20g of ethanol and 10g of acetonitrile to a three-necked flask, stir evenly, add 0.3g of triethylamine to adjust the pH value, add 0.3g of tetramethylammonium hydroxide (TMAH, catalyst), and continue stirring for 5 minutes until completely dissolved; slowly add 20g of γ-aminopropyltriethoxysilane (APTES, monomer) by a peristaltic pump at a drop rate of about 1.5mL / min. During the addition, keep the system temperature at 70°C (oil bath heating) and continue reflux stirring; after the addition is complete, maintain reflux stirring at 70°C for 18 hours to ensure that the mixture is completely dissolved. The silane is completely hydrolyzed to form a stable T8 cage structure (the residual amount of the raw material is monitored by gas chromatography until the γ-aminopropyltriethoxysilane content is less than 2%). After the reaction, the system is transferred to a rotary evaporator and evaporated to remove volatile solvents such as ethanol and acetonitrile at 60°C under reduced pressure to obtain a crude product. 50 mL of toluene is added to the crude product, and the product is stirred and washed to remove water-soluble impurities. The toluene is then evaporated again under reduced pressure to remove the toluene. The washing-reduced pressure evaporation step is repeated twice to obtain a yellow, transparent, viscous, colloidal γ-aminopropyl POSS (amino POSS).

[0037] The preparation process of amino POSS modified silicone resin is as follows:

[0038] 10 g of γ-aminopropyl POSS and 20 g of hydroxyl-terminated polydimethylsiloxane (HT-PDMS) were added to a reaction flask, and 100 g of toluene and 0.1 g of dibutyltin dilaurate were added. Under nitrogen protection, the temperature was raised to 120°C with stirring for 4 hours. Isocyanate was added and the reaction was continued for 2 hours. After the reaction was completed, the mixture was cooled to room temperature and the toluene solvent was removed by vacuum distillation. The mixture was precipitated with n-hexane, filtered, and dried in vacuo to obtain an amino POSS-modified silicone resin with an amino content of 15% and a viscosity of 5000-10000 mPa·s at 25°C.

[0039] Preparation process of epoxy-modified silicone resin: 10.4g of tetraethyl orthosilicate (TEOS, 0.05mol), 3.6g of methyltriethoxysilane (MTES, 0.02mol) and 1.5g of diethoxydimethylsilane (DEDMS, 0.01mol) were weighed, 3.1g of KH560 (20% of the total weight of the monomers) was added, and magnetic stirring was performed for 10 minutes until the mixture was uniformly mixed to obtain a mixed monomer; 50g of anhydrous ethanol was added to a three-necked flask and heated to 80°C; the mixed monomer was poured into the three-necked flask, dilute hydrochloric acid was added dropwise to adjust the pH value to about 3-4, and 5g of deionized water was slowly added dropwise to the reaction system via a peristaltic pump (dropping rate 1.5r / s, dropping time 1h). After the dropwise addition was completed, the reaction was continued to be kept warm for 5 hours to obtain an epoxy-modified silicone with an epoxy group content of 13%.

[0040] Performance testing:

[0041] 1. High temperature resistance test:

[0042] Referring to GB / T 1735-2020 "Determination of Heat Resistance of Paint Films", thin steel plates (50×120×0.5 mm) coated with the high-temperature resistant coating of the present invention, traditional silicone coating, and inorganic ceramic coating were placed in a muffle furnace and heated continuously to 400°C, 500°C, and 600°C at a rate of 5°C / min. The coating conditions were observed after holding for 10 hours. The test results are shown in Table 1: the traditional silicone coating can withstand a temperature of 400°C and fails due to carbonization at high temperatures; the inorganic ceramic coating requires high-temperature curing, and because the thermal expansion coefficient is significantly different from that of the metal substrate (about 15×10 -6 / ℃vs steel 11×10 -6 / ℃), resulting in cracking; the high-temperature resistant coating of the present invention forms a stable ceramic layer at 600℃, which is attributed to the reaction of -Si-O-Si- chains generated by thermal oxidation of silicone with high-temperature resistant fillers (such as ZnO and glass powder) to form a Si-OM (M=metal) network, breaking the temperature resistance limit of traditional silicone.

[0043] Table 1 High temperature resistance test results

[0044]

[0045] 2. High temperature crack resistance test:

[0046] Cyclic thermal shock test: Thin steel plates (50×120×0.5mm) coated with the high-temperature resistant coating of the present invention, traditional silicone coating, and inorganic ceramic coating were cycled back and forth between room temperature and 600°C (each cycle included: standing at room temperature for 30 minutes → heating to 600°C (rate 10°C / min), keeping warm for 1 hour → cooling to room temperature in the furnace). The cracking and peeling of the coating were observed, and the number of cycles was recorded. The results showed that the high-temperature resistant coating of the present invention could withstand ≥20 cycles from room temperature to 600°C without obvious cracks; the traditional silicone coating developed a network of cracks after the third cycle; and the inorganic ceramic coating peeled off at the edge after the fifth cycle. The reason may be that the POSS nanoparticles (particle size ≈100nm) of the high-temperature resistant coating of the present invention act as "nanosprings", absorbing thermal stress through elastic deformation, while inducing silver cracks inside the coating to disperse energy and inhibit crack propagation.

[0047] 3. Adhesion test:

[0048] The cross-hatch method (GB / T 9286-1998) was used to scratch a 1 mm × 1 mm grid on the surface of a thin steel plate coated with the high-temperature resistant coating of the present invention, a traditional silicone coating, and an inorganic ceramic coating. 3M tape was attached and then vertically torn off. The coating peeling was observed at room temperature and after cooling from high temperature (600°C for 2 hours) to room temperature. The results are shown in Table 2. The high-temperature resistant coating of the present invention has excellent adhesion at room temperature, which is due to the formation of hydrogen bonds between amino POSS and hydroxyl groups on the substrate surface and the cross-linking effect of epoxy-modified silicone. The adhesion retention rate remains high after high temperature because the filler and the substrate form a mechanical bite and chemical anchoring during the ceramicization process (for example, ZnO reacts with Fe3O4 on the steel surface to form ZnFe2O4).

[0049] Table 2 Adhesion test results

[0050]

[0051] 4. Corrosion resistance test:

[0052] Salt spray test (GB / T 1771-2007): Thin steel plates having the high-temperature resistant coating of the present invention, a conventional organosilicon coating, and an inorganic ceramic coating were continuously sprayed in a 5% NaCl solution atomization environment for 500 hours. The corrosion spread was observed. The results showed that the coating of the present invention was free of rust, while the conventional organosilicon coating showed pitting (pore diameter ≈ 0.2 mm), and the inorganic ceramic coating showed rust due to microcrack penetration.

[0053] Acid-base immersion test: Thin steel plates with the high-temperature resistant coating of the present invention, a traditional silicone coating, and an inorganic ceramic coating were immersed in 10% HCl and 10% NaOH solutions, respectively. After being left at room temperature for 72 hours, the coating swelling and shedding were evaluated. The results showed that the coating thickness of the present invention changed by ≤2%, the swelling rate of the traditional silicone coating was >10%, and the edge of the inorganic ceramic coating collapsed.

[0054] The high-temperature resistant coating of the present invention forms a dense ceramic layer to isolate the corrosive medium. At the same time, the hydrophobic cage structure of POSS reduces the hygroscopicity of the coating and inhibits electrochemical corrosion. Traditional silicone coatings produce micropores due to high-temperature oxidation, and inorganic ceramic coatings become corrosion channels due to brittle cracks.

[0055] 5. Flexibility test:

[0056] Cupping test (GB / T 9753-2007): A cupping tester was used to apply pressure to thin steel plates having the high-temperature resistant coating of the present invention, a traditional organosilicon coating, and an inorganic ceramic coating. The maximum penetration depth (mm) at which the coating cracked was recorded. The results were: ≥5mm for the coating of the present invention, ≈4mm for the traditional organosilicon coating, and ≤2mm for the inorganic ceramic coating. This indicates that the flexibility of the organosilicon backbone of the coating of the present invention and the dispersibility of the POSS particles work synergistically, making the coating less susceptible to cracking during deformation and adapting to dynamic high-temperature environments (such as thermal expansion and contraction of pipelines).

[0057] It can be seen from the above performance test results that the high-temperature resistant POSS modified silicone ceramic coating of the present invention achieves long-term protection at 400-600°C through the "organic-inorganic dynamic transformation" mechanism, taking into account both the convenience of room temperature construction and the reliability of high-temperature protection; POSS nano-enhancement technology solves the core contradiction of traditional high-temperature resistant coatings being "hard, brittle and easy to crack" or "high-temperature failure". In high-temperature corrosion scenarios such as petrochemicals and energy equipment, the comprehensive performance is better than that of single organic or inorganic coatings, which can extend the life of equipment by 3-5 times and reduce maintenance costs by more than 50%; the room-temperature curing characteristics make it suitable for emergency repairs and on-site protection of large components, expanding the application boundaries of high-temperature resistant coatings and providing a solid performance basis for their promotion in high-temperature industrial fields.

[0058] The above is only the best embodiment of the present invention. It should be noted that, for those skilled in the art, without departing from the principles of the present invention, several modifications or equivalent substitutions can be made to the technical solution of the present invention, which can still achieve the technical effects of the present invention and should also be considered to fall within the scope of protection of the present invention.

Claims

1. A high temperature resistant POSS modified organosilicon ceramic coating, characterized in that, The base materials are amino POSS modified silicone resin and epoxy modified silicone resin, with high temperature resistant fillers and solvents. The weight ratio of each component is: Amino POSS modified silicone resin 10-30%; Epoxy modified silicone resin 5-30%; High temperature resistant filler 30-70%; The balance is solvent.

2. The POSS modified organosilicon ceramic coating according to claim 1, wherein: The invention also includes an auxiliary agent, which is one or more of a dispersant, a wetting agent, and a defoaming agent, and the weight ratio of the auxiliary agent is ≤5%.

3. The POSS modified organosilicon ceramic coating according to claim 1 or 2, characterized in that: The amino content of the amino POSS modified organic silicone resin is 5-30%, and the epoxy content of the epoxy modified organic silicone resin is 5-30%.

4. The POSS modified organosilicon ceramic coating according to claim 3, wherein: The high-temperature resistant filler includes zinc oxide, titanium dioxide, silicon nitride, zirconium oxide, boron nitride, aluminum oxide, chromium oxide, and glass powder, wherein the weight ratio of each component is: zinc oxide 5-15%, titanium dioxide 5-30%, silicon nitride 5-30%, zirconium oxide 5-30%, boron nitride 5-15%, aluminum oxide 5-15%, chromium oxide 5-10%, and glass powder 1-8%.

5. The POSS modified organosilicon ceramic coating according to claim 4, characterized in that: The solvent is a combination of one or more of xylene, toluene or ethanol.

6. The method for preparing the POSS modified organosilicon ceramic coating according to claim 5, characterized in that: The following steps are involved: (1) preparing an amino POSS modified silicone resin: subjecting amino POSS to a cross-linking reaction with an organosilicon prepolymer under the action of a cross-linking agent and / or a catalyst to obtain an amino POSS modified silicone resin; (2) Preparation of epoxy-modified silicone resin: Add 5-30% of the weight of epoxy coupling agent to alkoxysilane monomer, mix evenly, add to anhydrous ethanol, adjust the pH to 3-4 at 60-90°C, add deionized water dropwise, and continue to heat and react for 3-8 hours to obtain epoxy-modified silicone resin; (3) Mixing and dispersion: amino POSS modified silicone resin, epoxy modified silicone resin, high temperature resistant filler and solvent are mixed in proportion, and dispersed evenly by high-speed grinding equipment to obtain high temperature resistant POSS modified silicone-ceramic coating.

7. The preparation method according to claim 6, characterized in that The organosilicon prepolymer in step (1) is hydroxy silicone oil or hydrogen silicone oil; the cross-linking agent is isocyanate or silane coupling agent; and the catalyst is an organotin compound.

8. The preparation method according to claim 6, characterized in that: The alkoxysilane monomer described in step (2) is a mixed monomer of ethyl orthosilicate, methyltriethoxysilane, and diethoxydimethylsilane in a molar ratio of (3-7): (1-2): (0.5-1); and the epoxy coupling agent is KH560, KH570 or γ-glycidoxypropyltrimethoxysilane.

9. The preparation method according to claim 6, characterized in that: The rotation speed of the high-speed grinding equipment is 1500-3000 r / min, and the grinding time is 20-60 minutes.

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