High-temperature-resistant metal surface coating and preparation method thereof

Abstract

The invention discloses a high-temperature-resistant metal surface coating and a preparation method thereof, and the high-temperature-resistant metal surface coating comprises the following components in parts by weight: 40-60 parts of ceramic silicon resin, 20-30 parts of polyether sulfone modified organic fluorine resin, 8-10 parts of water-based polyimide resin, 10-15 parts of zinc chrome, 4-6 parts of boron nitride, 3-5 parts of a modified phenolic aldehyde amine curing agent, 8-15 parts of barium sulfate and 8-10 parts of short carbon fiber. The invention relates to the technical field of preparation of metal surface coatings. The metal surface coating is prepared from the following components in parts by weight: 5-8 parts of hollow glass beads, 2-4 parts of a silane coupling agent, 1-3 parts of an organic silicon defoaming agent, 8-12 parts of a dispersing agent, 1-2 parts of a thickening agent and 6-9 parts of a composite coating anti-aging agent. According to the high-temperature-resistant metal surface coating and the preparation method thereof, the ceramic silicon resin, the polyethersulfone modified organic fluororesin and the water-based polyimide resin are adopted as main resin components, a stable structure can be formed at high temperature, and the high-temperature-resistant metal surface coating can bear higher temperature.

Description

Technical Field

[0001] The present invention relates to the technical field of metal surface coating preparation, and specifically to a high-temperature resistant metal surface coating and a preparation method thereof. Background Art

[0002] In many industrial fields, high-temperature resistant metal surface coatings play a crucial role. For example, in the aerospace field, engine components, outer shells of aircraft, etc. need to withstand extreme high-temperature environments. Good high-temperature resistant coatings can protect metal components, ensure their stable performance and extended service life, and guarantee the safe operation of aircraft. In the energy industry, such as thermal power generation equipment and high-temperature reaction devices in petrochemical industry, the metal surface is in harsh working conditions such as high temperature and corrosion for a long time. High-temperature resistant coatings can effectively prevent metal corrosion and oxidation, improve the reliability and operation efficiency of equipment, and reduce maintenance costs.

[0003] At present, there are many problems with some existing high-temperature resistant coatings on the market. The anti-aging performance is insufficient. Under the action of environmental factors such as high temperature and light for a long time, phenomena such as aging and cracking are likely to occur, resulting in a decline in the protective performance of the coating. Their composition is not optimized enough to meet the requirements of high temperature resistance, good adhesion, mechanical properties, etc. simultaneously. Therefore, developing a metal surface coating with excellent high-temperature resistance and good anti-aging performance has become an urgent need in the current industrial field. Summary of the Invention

[0004] To achieve the above objectives, the present invention is realized through the following technical solutions: A high-temperature resistant metal surface coating, including the following weight components: ceramized silicone resin: 40 - 60 parts, polyethersulfone-modified organic fluororesin: 20 - 30 parts, waterborne polyimide resin: 8 - 10 parts, zinc chromate yellow: 10 - 15 parts, boron nitride: 4 - 6 parts, modified phenolic amine curing agent: 3 - 5 parts, barium sulfate: 8 - 15 parts, chopped carbon fiber: 8 - 10 parts, hollow glass microspheres: 5 - 8 parts, silane coupling agent: 2 - 4 parts, organic silicone defoamer: 1 - 3 parts, dispersant: 8 - 12 parts, thickener: 1 - 2 parts, composite coating anti-aging agent: 6 - 9 parts; Among them, the specific preparation method of the composite coating anti-aging agent is as follows: Step 1: Dry nano-zinc oxide in a vacuum drying oven at 80°C for 4 hours to remove moisture, and then perform ultra-fine pulverization treatment. Grind 4-hydroxybenzophenone, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole, and composite hindered amine light stabilizer in a ball mill respectively; Step 2: Add acrylic resin into the reaction kettle, add 5%-8% ethyl acetate as the solvent, stir, and heat up the temperature to 50℃-55℃. Then add the 4-hydroxybenzophenone, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole, composite hindered amine light stabilizer, nano-zinc oxide, antioxidant, and dispersant treated in Step 1 into the reaction kettle, and continue stirring with an interval of 15 minutes for each addition. Step 3: Use an ultrasonic disperser to perform ultrasonic dispersion treatment on the mixture in the reaction kettle, keep the temperature at 50℃±2℃ during the ultrasonic process, and control the temperature through a circulating water bath. Step 4: Remove the solvent from the ultrasonically dispersed mixture by vacuum distillation. Control the distillation temperature at 60-70℃ and the vacuum degree at -0.08MPa to -0.1MPa. After removing the solvent, cool to room temperature to obtain the composite coating anti-aging agent.

[0005] Preferably, the silane coupling agent is bis-[γ-(triethoxysilyl)propyl]tetrasulfide, and the thickener is fumed silica thickener.

[0006] Preferably, the specific preparation method of the composite hindered amine light stabilizer in Step 1 is as follows: Step A1: Add tetrahydrodicyclopentadienylamine and potassium carbonate catalyst into the reaction kettle. Under nitrogen protection, add bromoalkane, control the reaction temperature at 80-90℃, and react for 6-8 hours. After the reaction, cool, filter, and wash to obtain the hindered amine compound A. Step A2: Add hydrogen siloxane and tetramethylpiperidineamine derivative into the reaction vessel, add chloroplatinic acid catalyst, heat and stir, and react at 60-70℃ for 4-6 hours to obtain the hindered amine compound B. Step A3: First, add the carrier resin phenolic modified epoxy resin into the mixer, start stirring, set the rotation speed at 800-1000 revolutions per minute, add antioxidant 1010, ultraviolet absorber, and dispersant in sequence, mix for 15-20 minutes, reduce the stirring speed to 500-600 revolutions per minute, then add hindered amine compound A and hindered amine compound B in sequence. After the addition is completed, increase the stirring speed to 1200-1500 revolutions per minute and continue stirring for 30-40 minutes. Step A4: Extrude and pelletize the uniformly mixed material through a twin-screw extruder. Cool and pelletize the extruded material to obtain the composite hindered amine light stabilizer particles.

[0007] Preferably, the ultraviolet absorber in Step A3 is a triazine derivative, and the dispersant in Step A3 is polyethylene wax.

[0008] Preferably, the composite coating anti-aging agent comprises the following components by weight: 4-hydroxybenzophenone: 12-15 parts, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole 12-14 parts, hindered amine light stabilizer 18-20 parts, nano-zinc oxide 14-16 parts, acrylic resin 35-45 parts, antioxidant 1-2.5 parts, dispersant 0.8-1.6 parts.

[0009] A preparation method of a high-temperature resistant metal surface coating comprises the following preparation steps: Step S1: Put the ceramized silicone resin, polyethersulfone-modified organic fluororesin and waterborne polyimide resin into a reaction kettle, heat to 40-50 °C, and stir at 100-200 revolutions per minute for 30 minutes to obtain the mixed resin A; Put boron nitride, barium sulfate, and chopped carbon fiber into a vacuum drying oven respectively. After drying, grind them respectively with a grinding device, and reserve them after filtration. The hollow glass microspheres are first preheated at 80-100 °C for 1-2 hours; Step S2: In a reaction kettle equipped with a high-speed disperser, a heating device and a temperature control monitoring speed regulation system, xylene and n-butanol are mixed in a volume ratio of 3:1 to obtain a solvent, and the boron nitride, barium sulfate, chopped carbon fiber and hollow glass microspheres pretreated in Step S1 are added, and a dispersant is added; Step S3: Pour the mixed resin A pretreated in Step S1 into the reaction kettle; Step S4: In the reaction kettle, add a silane coupling agent, an organosilicon defoamer, and a composite coating anti-aging agent in sequence, and finally add a thickener, and stir to obtain a high-temperature resistant metal surface coating.

[0010] Preferably, the total amount of the mixed solvent of toluene and n-butanol in Step S2 is 15-20% of the total amount of the resin.

[0011] Preferably, the temperature control monitoring speed regulation system in Step S2 has the following control method: The first step: System initialization; (2), Set the temperature control parameters, the lower limit of the high-speed dispersion operation temperature is 40 °C, the upper limit is 50 °C, and the allowable range of temperature fluctuation is ±1 °C; (3), Set the speed regulation control parameters, the initial stirring speed is 500 revolutions per minute, the speed increase gradient during the filler addition process, and the final high-speed dispersion speed target value is 1800 revolutions per minute, and the allowable range of speed deviation is ±35 revolutions per minute.

[0012] The second step: Preheat the hollow glass microspheres; (1), The temperature sensor monitors the temperature in the reaction kettle in real time. When the hollow glass microspheres start to be preheated, the system records the initial temperature T0; (2) As the preheating process progresses, the temperature sensor continuously transmits temperature data to the control system, and the operator can view the temperature changes in real time through the display screen; (3) The lower limit of the preheating target temperature is 80°C, and the upper limit is 100°C. If the temperature is lower than the preheating target temperature range, the heating device control system is activated, and the heating power is gradually increased to raise the temperature; (4) When the temperature approaches or reaches the upper limit of the preheating target temperature of 100°C, the heating device control system reduces the power or stops heating, and maintains the temperature within the preheating target temperature range through feedback control, with the temperature fluctuation controlled within ±2°C; The third step: Filler addition and high-speed dispersion; (1) When starting to add the filler, the rotation speed monitoring device records the initial stirring speed as 500 revolutions per minute. As the filler is gradually added, the system increases the stirring speed in accordance with the preset speed increase gradient, monitors the change in the stirring speed in real time, and feeds the data back to the control system; (2) According to the preset program, the drive motor control system of the high-speed disperser increases the stirring speed by 100 revolutions per minute every 5 minutes during the filler addition process until the high-speed dispersion speed target value of 1800 revolutions per minute is reached. During the high-speed dispersion process, if there is a deviation between the actual rotation speed and the set target rotation speed, and the deviation exceeds ±35 revolutions per minute, the speed control system immediately makes fine adjustments to the drive motor, increasing or decreasing the motor power to restore the stirring speed to the target range; (3) The temperature sensor continuously monitors the temperature during the entire filler addition and high-speed dispersion process. Due to the change in the stirring speed and the material mixing reaction, the temperature changes. When the temperature is lower than the lower limit of the high-speed dispersion operation temperature of 40°C, the heating device is activated to raise the temperature. When the temperature is higher than the upper limit of 50°C, the cooling device is activated to lower the temperature, and the temperature fluctuation is always controlled within ±1°C.

[0013] Preferably, the working process of the heating device control system in the second step is as follows: Step B1: During the heating process, the high-precision temperature sensor monitors the temperature of the solvent and material mixing system in the reaction kettle. The temperature sensor transmits the temperature data collected in real time to the controller in the form of an electrical signal. After receiving the temperature data, the controller processes and analyzes it, and compares the actual temperature with the set target temperature range; Step B2: When the actual temperature is lower than the target temperature lower limit, the controller issues an instruction to increase the heating power. The heating device may use the method of resistance wire heating. The controller adjusts the heating power. As the temperature gradually approaches the target temperature range, the controller gradually reduces the increase amplitude of the heating power according to the preset algorithm; Step B3: When the temperature reaches the target temperature range, the heating device control system enters the temperature holding stage. At this time, the controller monitors the temperature change and finely adjusts the heating power to compensate for the slight temperature drop caused by heat dissipation and other factors. Step B4: The temperature sensor, as a feedback component, continuously feeds back the temperature information inside the reactor to the controller. The controller compares the temperature feedback data with the set temperature, calculates the temperature deviation, and if the temperature deviation exceeds ±2°C, the controller adjusts the heating power.

[0014] Preferably, the algorithm content preset by the controller in Step B2 is as follows: The temperature range of the entire heating process is divided into multiple intervals. Let the lower limit of the target temperature be T1 and the upper limit be T2, and the intervals can be divided as follows: Low-temperature interval: from T0 to T1 - T1; Medium-temperature interval: from T1 - T1 to T2 - T2; High-temperature interval: from T2 - T2 to T2; In the low-temperature interval, let the initial heating power be P0, and the increase amplitude of the heating power in this interval is P1, that is, the first heating power adjustment is P0 + P1, and the second heating power adjustment is P0 + 2 P1; In the medium-temperature interval, let the increase amplitude of the heating power decrease by P2 for every 1°C increase in temperature in the medium-temperature interval. When the temperature starts to rise from T1 - T1, the increase amplitude of the heating power at this time is = P1 - P2; As the temperature continues to rise, let the current temperature be T, where T1 - T1 < T < T2 - T2, the calculation formula for the increase amplitude of the heating power is = P1 - P2 × (T - (T1 - T1)); In the high-temperature interval, when the temperature enters the high-temperature interval, the increase amplitude of the heating power is extremely small and approaches zero. When the temperature reaches T2 - T2, the increase amplitude of the heating power decreases to P3; When the temperature rises from T2 - T2 rises to T2. Let the current temperature be T, T2 - T2 < T < T2, the increasing range of heating power further decreases, The calculation formula is = P3 - P4 (T - (T2 - T2)), where P4 is the further decreased amplitude value in the high temperature range.

[0015] The present invention provides a high temperature resistant metal surface coating and a preparation method thereof. It has the following beneficial effects: The high-temperature resistant metal surface coating and its preparation method use ceramized silicone resin, polyethersulfone-modified organic fluororesin, and waterborne polyimide resin as the main resin components. The ceramized silicone resin is a thermosetting polysiloxane polymer with a highly crosslinked structure. This crosslinked structure is like a three-dimensional network that tightly connects the molecules. At high temperatures, the crosslinked structure can prevent the free movement and slippage of molecular chains, keeping the resin in a stable form and enabling it to withstand higher temperatures. At the same time, the heat insulation effect of hollow glass microspheres and the strengthening effect of chopped carbon fibers reduce the transfer and accumulation of heat in the coating, further improving the high-temperature resistance of the coating. Compared with traditional coatings, it can maintain stability at higher temperatures. The oxide film formed by zinc chromate mainly fills the pores on the metal surface, while the flaky structure of boron nitride provides physical barrier on a larger scale. The flaky structure of boron nitride can cover the preliminary protective film formed by zinc chromate, further improving the integrity of the protective film. Through the synergistic effect of zinc chromate and boron nitride, a dense protective film is formed on the metal surface to prevent the erosion of corrosive media such as acids, alkalis, and salts. The good coating adhesion and barrier properties effectively isolate the metal from the external environment, reducing the probability of electrochemical corrosion. Through a specially prepared composite coating anti-aging agent, which contains components such as 4-hydroxybenzophenone, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole, hindered amine light stabilizer, and nano-zinc oxide. Both 4-hydroxybenzophenone and 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole belong to ultraviolet absorbers.Their molecular structures contain functional groups capable of absorbing ultraviolet energy. When the coating is exposed to ultraviolet light, these functional groups can absorb the energy of ultraviolet photons and undergo intramolecular electronic transitions. For example, an electronic transition occurs between the carbonyl group and the hydroxyl group in the 4-hydroxybenzophenone molecule, converting the ultraviolet energy into harmless heat energy and releasing it, thereby preventing the ultraviolet light from directly breaking the chemical bonds of the coating. 2-(2'-Hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole also absorbs ultraviolet light through a similar intramolecular energy conversion mechanism. These two components have a certain complementarity in the ultraviolet absorption spectrum. 4-Hydroxybenzophenone mainly absorbs ultraviolet light with a wavelength range of 280-340 nm, while 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole has a better absorption effect on ultraviolet light with a wavelength range of 300-380 nm. In the actual environment, the wavelength range of ultraviolet light is relatively wide. The combination of the two can absorb ultraviolet light more comprehensively, expand the wavelength range of ultraviolet protection, reduce the photoaging effect of ultraviolet light on the coating, effectively absorb ultraviolet light, capture free radicals, interrupt the photooxidation chain reaction, thereby delaying the aging process of the coating and extending the service life of the coating. Moreover, the precise temperature control and stable speed control work together, enabling the components in the coating preparation process to be fully and evenly mixed, and the chemical reaction to proceed under suitable conditions, ensuring the performance stability of the coating in different batch productions. Detailed implementation mode

[0016] The following will combine 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 a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0017] First embodiment, the present invention provides a technical solution: a high-temperature resistant metal surface coating, including the following weight components: ceramicized silicone resin: 40 parts, polyethersulfone-modified organic fluororesin: 20 parts, water-based polyimide resin: 8 parts, zinc chromate yellow: 10 parts, boron nitride: 4 parts, modified phenolic amine curing agent: 3 parts, barium sulfate: 8 parts, chopped carbon fiber: 8 parts, hollow glass microspheres: 5 parts, bis-[γ-(triethoxysilyl)propyl] tetrasulfide: 2 parts, silicone defoamer: 1 part, dispersant: 8 parts, fumed silica thickener: 1 part, composite coating anti-aging agent: 6 parts; Among them, the specific preparation method of the composite coating anti-aging agent is as follows: Step 1: Dry nano-zinc oxide in a vacuum drying oven at 80 °C for 4 hours to remove moisture, and then perform ultrafine grinding. Grind 4-hydroxybenzophenone, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole, and the composite hindered amine light stabilizer separately in a ball mill. Step 2: Add acrylic resin to a reaction kettle, add 5% ethyl acetate as a solvent, and stir. Raise the temperature to 50 °C and add the 4-hydroxybenzophenone, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole, composite hindered amine light stabilizer, nano-zinc oxide, antioxidant, and dispersant treated in Step 1 to the reaction kettle, and continue stirring, with a 15-minute interval for each addition. Step 3: Use an ultrasonic disperser to perform ultrasonic dispersion treatment on the mixture in the reaction kettle. Keep the temperature at 50 °C ± 2 °C during the ultrasonic process, and control the temperature through a circulating water bath. Step 4: Remove the solvent from the ultrasonically dispersed mixture by vacuum distillation. Control the distillation temperature at 60 °C and the vacuum degree at -0.08 MPa. After removing the solvent, cool to room temperature to obtain the composite coating anti-aging agent.

[0018] The specific preparation method of the composite hindered amine light stabilizer in Step 1 is as follows: Step A1: Add tetrahydrodicyclopentadienylamine and potassium carbonate catalyst to a reaction kettle. Under nitrogen protection, add bromoalkane, control the reaction temperature at 80 °C, and react for 6 hours. After the reaction, cool, filter, and wash to obtain the hindered amine compound A. Step A2: Add hydrosiloxane and tetramethylpiperidineamine derivative to a reaction vessel, add chloroplatinic acid catalyst, heat and stir, and react at 60 °C for 4 hours to obtain the hindered amine compound B. Step A3: First, add the carrier resin phenolic modified epoxy resin to a mixer, start stirring, set the rotation speed at 800 revolutions per minute, and sequentially add antioxidant 1010, triazine derivative, and polyethylene wax, and mix for 15 minutes. Then reduce the stirring speed to 500 revolutions per minute, and sequentially add hindered amine compound A and hindered amine compound B. After the addition is completed, increase the stirring speed to 1200 revolutions per minute and continue stirring for 30 minutes. Step A4: Extrude and pelletize the uniformly mixed material through a twin-screw extruder. Cool and pelletize the extruded material to obtain composite hindered amine light stabilizer particles.

[0019] The composite coating anti-aging agent includes the following weight components: 4-hydroxybenzophenone: 12 parts, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole 12 parts, hindered amine light stabilizer 18 parts, nano-zinc oxide 14 parts, acrylic resin 35 parts, antioxidant 1 part, dispersant 0.8 part.

[0020] A preparation method of a high-temperature resistant metal surface coating, comprising the following preparation steps: Step S1: Put the ceramized silicone resin, polyethersulfone-modified organic fluororesin and waterborne polyimide resin into a reaction kettle, heat to 40 °C, and stir at 100 revolutions per minute for 30 minutes to obtain a mixed resin A; Put boron nitride, barium sulfate, and chopped carbon fibers into a vacuum drying oven respectively. After drying, grind them respectively using a grinding device, and set aside after filtration. For hollow glass microspheres, first perform a preheating treatment, preheat at 80 °C for 1 hour; Step S2: In a reaction kettle equipped with a high-speed disperser, a heating device and a temperature control monitoring speed regulation system, mix xylene and n-butanol in a volume ratio of 3:1 to obtain a solvent, add the boron nitride, barium sulfate, chopped carbon fibers and hollow glass microspheres pretreated in Step S1, and add a dispersant; Step S3: Pour the mixed resin A pretreated in Step S1 into the reaction kettle; Step S4: In the reaction kettle, sequentially add bis-[γ-(triethoxysilyl)propyl]tetrasulfide, an organosilicon defoamer, a composite coating anti-aging agent, and finally add a fumed silica thickener, and stir to obtain a high-temperature resistant metal surface coating.

[0021] The temperature control monitoring speed regulation system in Step S2 has the following control method: The first step: System initialization; (2) Set the temperature control parameters. The lower limit of the high-speed dispersion operation temperature is 40 °C, the upper limit is 50 °C, and the allowable temperature fluctuation range is ±1 °C; (3) Set the speed regulation control parameters. The initial stirring speed is 500 revolutions per minute, the speed increase gradient during the filler addition process, and the final high-speed dispersion speed target value is 1800 revolutions per minute. The allowable range of rotational speed deviation is ±35 revolutions per minute.

[0022] The second step: Preheat the hollow glass microspheres; (1) The temperature sensor continuously monitors the temperature inside the reaction kettle. When the hollow glass microspheres start to be preheated, the system records the initial temperature T0; (2) As the preheating process progresses, the temperature sensor continuously transmits the temperature data to the control system, and the operator can view the temperature change in real time through the display screen; (3) The lower limit of the preheating target temperature is 80 °C, the upper limit is 100 °C. If the temperature is lower than the preheating target temperature range, the heating device control system is started, and the heating power is gradually increased to raise the temperature; (4) When the temperature approaches or reaches the preheating target temperature upper limit of 100 °C, the heating device control system reduces the power or stops heating, and maintains the temperature within the preheating target temperature range through feedback control, with the temperature fluctuation controlled within ±2 °C; Step 3: Filler addition and high-speed dispersion; (1) When starting to add the filler, the rotation speed monitoring device records the initial stirring speed as 500 revolutions per minute. As the filler is gradually added, the system increases the stirring speed in accordance with the preset speed increase gradient, monitors the change in the stirring speed in real time, and feeds the data back to the control system; (2) According to the preset program, the drive motor control system of the high-speed disperser increases the stirring speed by 100 revolutions per minute every 5 minutes during the filler addition process until the target value of the high-speed dispersion speed of 1800 revolutions per minute is reached. During the high-speed dispersion process, if there is a deviation between the actual rotation speed and the set target rotation speed, and the deviation exceeds ±35 revolutions per minute, the speed control system immediately makes fine adjustments to the drive motor, increasing or decreasing the motor power to restore the stirring speed to the target range; (3) The temperature sensor continuously monitors the temperature during the entire filler addition and high-speed dispersion process. Due to the change in the stirring speed and the material mixing reaction, when the temperature is lower than the lower limit of the high-speed dispersion operating temperature of 40°C, the heating device is started to raise the temperature. When the temperature is higher than the upper limit of 50°C, the cooling device is started to lower the temperature, and the temperature fluctuation is always controlled within ±1°C.

[0023] The working process of the heating device control system in Step 2 is as follows: Step B1: During the heating process, the high-precision temperature sensor monitors the temperature of the solvent and material mixing system in the reaction kettle. The temperature sensor transmits the temperature data collected in real time to the controller in the form of an electrical signal. After receiving the temperature data, the controller processes and analyzes it, and compares the actual temperature with the set target temperature range; Step B2: When the actual temperature is lower than the lower limit of the target temperature, the controller issues an instruction to increase the heating power. The heating device may use the method of resistance wire heating. The controller adjusts the heating power. As the temperature gradually approaches the target temperature range, the controller gradually reduces the increase amplitude of the heating power according to the preset algorithm; Step B3: When the temperature reaches the target temperature range, the heating device control system enters the temperature holding stage. At this time, the controller monitors the temperature change and makes fine adjustments to the heating power to compensate for the slight temperature drop caused by factors such as heat dissipation; Step B4: The temperature sensor, as a feedback element, continuously feeds back the temperature information in the reaction kettle to the controller. The controller compares the temperature feedback data with the set temperature, calculates the temperature deviation, and if the temperature deviation exceeds ±2°C, the controller adjusts the heating power.

[0024] The content of the algorithm preset by the controller in Step B2 is as follows: Divide the temperature range of the entire heating process into multiple intervals. Let the lower limit of the target temperature be T1 and the upper limit be T2. The intervals can be divided as follows: Low-temperature interval: from T0 to T1 - T1; Medium-temperature interval: from T1 - T1 to T2 - T2; High-temperature interval: from T2 - T2 to T2; In the low-temperature interval, let the initial heating power be P0. The increase amplitude of the heating power in this interval is P1 each time. That is, the heating power is adjusted to P0 + P1 for the first time, and the heating power is adjusted to P0 + 2 P1 for the second time; In the medium-temperature interval, let the increase amplitude of the heating power decrease by P2 for every 1°C increase in temperature. When the temperature starts to rise from T1 - T1, the increase amplitude of the heating power at this time is = P1 - P2; As the temperature continues to rise, let the current temperature be T, where T1 - T1 < T < T2 - T2. The calculation formula for the increase amplitude of the heating power is = P1 - P2 (T - (T1 - T1)); In the high-temperature interval, when the temperature enters the high-temperature interval, the increase amplitude of the heating power is extremely small and approaches zero. When the temperature reaches T2 - T2, the increase amplitude of the heating power decreases to P3; When the temperature rises from T2 - T2 to T2, let the current temperature be T, where T2 - T2 < T < T2. The increase amplitude of the heating power further decreases. The calculation formula is = P3 - P4 (T - (T2 - T2)), where P4 is the further decrease amplitude value in the high-temperature interval.

[0025] Second Embodiment, the present invention provides a technical solution: a high-temperature resistant metal surface coating, characterized by comprising the following components by weight: ceramized silicone resin: 50 parts, polyethersulfone modified organic fluororesin: 25 parts, waterborne polyimide resin: 9 parts, zinc chromate yellow: 12 parts, boron nitride: 5 parts, modified phenolic amine curing agent: 4 parts, barium sulfate: 11 parts, chopped carbon fiber: 9 parts, hollow glass microspheres: 6 parts, bis-[γ-(triethoxysilyl)propyl]tetrasulfide: 3 parts, organosilicon defoamer: 2 parts, dispersant: 10 parts, fumed silica thickener: 1.5 parts, composite coating anti-aging agent: 7 parts; Among them, the specific preparation method of the composite coating anti-aging agent is as follows: Step 1: Dry nano-zinc oxide in a vacuum drying oven at 80°C for 4 hours to remove moisture, and then perform ultrafine pulverization treatment. Grind 4-hydroxybenzophenone, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole, and the composite hindered amine light stabilizer in a ball mill respectively; Step 2: Add acrylic resin to the reaction kettle, add 6% ethyl acetate as a solvent, stir, and raise the temperature to 53°C. Add the 4-hydroxybenzophenone, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole, composite hindered amine light stabilizer, nano-zinc oxide, antioxidant, and dispersant treated in Step 1 to the reaction kettle, and continue to stir, with an interval of 15 minutes for each addition; Step 3: Use an ultrasonic disperser to perform ultrasonic dispersion treatment on the mixture in the reaction kettle. Keep the temperature at 50°C ± 2°C during the ultrasonic process, and control the temperature through a circulating water bath; Step 4: Remove the solvent from the ultrasonically dispersed mixture by vacuum distillation. Control the distillation temperature at 65°C and the vacuum degree at -0.09 MPa. After removing the solvent, cool to room temperature to obtain the composite coating anti-aging agent.

[0026] The specific preparation method of the composite hindered amine light stabilizer in Step 1 is as follows: Step A1: Add tetrahydrodicyclopentadienylamine and potassium carbonate catalyst to the reaction kettle. Under nitrogen protection, add bromoalkane, control the reaction temperature at 85°C, and react for 7 hours. After the reaction, cool, filter, and wash to obtain the hindered amine compound A; Step A2: Add hydrogen siloxane and tetramethylpiperidineamine derivative to the reaction vessel, add chloroplatinic acid catalyst, heat and stir, and react at 65°C for 5 hours to obtain the hindered amine compound B; Step A3: First, add the carrier resin phenolic modified epoxy resin into a mixer, start stirring, set the rotation speed at 900 revolutions per minute, sequentially add antioxidant 1010, triazine derivatives, and polyethylene wax, mix for 17 minutes, reduce the stirring speed to 550 revolutions per minute, then sequentially add amine blocker compound A and hindered amine compound B. After the addition is completed, increase the stirring speed to 1350 revolutions per minute and continue stirring for 35 minutes; Step A4: Extrude and pelletize the uniformly mixed material through a twin-screw extruder. The extruded material is cooled and pelletized to obtain composite hindered amine light stabilizer particles.

[0027] The composite coating anti-aging agent comprises the following weight components: 4-hydroxybenzophenone: 13 parts, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole 13 parts, hindered amine light stabilizer 19 parts, nano zinc oxide 15 parts, acrylic resin 40 parts, antioxidant 2 parts, dispersant 1.2 parts.

[0028] A preparation method of a high-temperature resistant metal surface coating comprises the following preparation steps: Step S1: Put the ceramized silicone resin, polyether sulfone modified organic fluororesin, and waterborne polyimide resin into a reaction kettle, heat to 45°C, and stir at 150 revolutions per minute for 30 minutes to obtain mixed resin A; Place boron nitride, barium sulfate, and chopped carbon fiber in a vacuum drying oven respectively. After drying, grind them respectively using a grinding device, filter, and reserve. For hollow glass microspheres, first perform a preheating treatment, preheat at 90°C for 1.5 hours; Step S2: In a reaction kettle equipped with a high-speed disperser, heating device, and temperature control monitoring speed regulation system, xylene and n-butanol are mixed at a volume ratio of 3:1 to obtain a solvent, add the boron nitride, barium sulfate, chopped carbon fiber, and hollow glass microspheres pretreated in Step S1, and add a dispersant; Step S3: Pour the mixed resin A pretreated in Step S1 into the reaction kettle; Step S4: In the reaction kettle, sequentially add bis-[γ-(triethoxysilyl)propyl] tetrasulfide, silicone defoamer, composite coating anti-aging agent, and finally add fumed silica thickener, and stir to obtain a high-temperature resistant metal surface coating.

[0029] Third Embodiment, the present invention provides a technical solution: a high-temperature resistant metal surface coating, characterized in that it comprises the following weight components: ceramized silicone resin: 60 parts, polyethersulfone-modified organic fluororesin: 30 parts, waterborne polyimide resin: 10 parts, zinc chromate yellow: 15 parts, boron nitride: 6 parts, modified phenolic amine curing agent: 5 parts, barium sulfate: 15 parts, chopped carbon fiber: 10 parts, hollow glass microspheres: 8 parts, bis-[γ-(triethoxysilyl)propyl]tetrasulfide: 4 parts, silicone defoamer: 3 parts, dispersant: 12 parts, fumed silica thickener: 2 parts, composite coating anti-aging agent: 9 parts; Among them, the specific preparation method of the composite coating anti-aging agent is as follows: Step 1: Dry nano-zinc oxide in a vacuum drying oven at 80°C for 4 hours to remove moisture, and then perform ultrafine pulverization treatment. Grind 4-hydroxybenzophenone, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole, and composite hindered amine light stabilizer in a ball mill respectively; Step 2: Add acrylic resin to a reaction kettle, add 8% ethyl acetate as a solvent, stir, and raise the temperature to 55°C. Add the 4-hydroxybenzophenone, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole, composite hindered amine light stabilizer, nano-zinc oxide, antioxidant, and dispersant treated in Step 1 to the reaction kettle, and continue to stir, with an interval of 15 minutes for each addition; Step 3: Use an ultrasonic disperser to perform ultrasonic dispersion treatment on the mixture in the reaction kettle. Keep the temperature at 50°C ± 2°C during the ultrasonic process, and control the temperature through a circulating water bath; Step 4: Remove the solvent from the ultrasonically dispersed mixture by vacuum distillation. Control the distillation temperature at 70°C and the vacuum degree at -0.1 MPa. The composite coating anti-aging agent after removing the solvent and cooling to room temperature.

[0030] The specific preparation method of the composite hindered amine light stabilizer in Step 1 is as follows: Step A1: Add tetrahydrodicyclopentadienylamine and potassium carbonate catalyst to a reaction kettle. Under nitrogen protection, add bromoalkane, control the reaction temperature at 90°C, and react for 8 hours. After the reaction is completed, cool, filter, and wash to obtain hindered amine compound A; Step A2: Add hydrogen siloxane and tetramethylpiperidineamine derivative to a reaction vessel, add chloroplatinic acid catalyst, heat and stir, and react at 70°C for 6 hours to obtain hindered amine compound B; Step A3: First, add the carrier resin phenolic modified epoxy resin into the mixer, start stirring, set the rotation speed to 1000 revolutions per minute, sequentially add antioxidant 1010, triazine derivatives, and polyethylene wax, mix for 20 minutes, reduce the stirring speed to 600 revolutions per minute, then sequentially add amine compound A and hindered amine compound B. After the addition is completed, increase the stirring speed to 1500 revolutions per minute and continue stirring for 40 minutes; Step A4: Extrude and pelletize the uniformly mixed material through a twin-screw extruder. The extruded material is cooled and pelletized to obtain composite hindered amine light stabilizer particles.

[0031] The composite coating anti-aging agent comprises the following weight components: 4-hydroxybenzophenone: 15 parts, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole 14 parts, hindered amine light stabilizer 20 parts, nano-zinc oxide 16 parts, acrylic resin 45 parts, antioxidant 2.5 parts, dispersant 1.6 parts.

[0032] A preparation method of a high-temperature resistant metal surface coating comprises the following preparation steps: Step S1: Put the ceramized silicone resin, polyethersulfone modified organic fluororesin, and waterborne polyimide resin into a reaction kettle, heat to 50 °C, and stir at 200 revolutions per minute for 30 minutes to obtain mixed resin A; Place boron nitride, barium sulfate, and chopped carbon fiber in a vacuum drying oven respectively. After drying, grind them respectively using a grinding device, filter, and reserve. For hollow glass microspheres, first perform preheating treatment, preheat at 100 °C for 2 hours; Step S2: In a reaction kettle equipped with a high-speed disperser, heating device, and temperature control monitoring and speed regulation system, mix xylene and n-butanol in a volume ratio of 3:1 to obtain a solvent, add the boron nitride, barium sulfate, chopped carbon fiber, and hollow glass microspheres pretreated in Step S1, and add a dispersant; Step S3: Pour the mixed resin A pretreated in Step S1 into the reaction kettle; Step S4: In the reaction kettle, sequentially add bis-[γ-(triethoxysilyl)propyl] tetrasulfide, silicone defoamer, composite coating anti-aging agent, and finally add fumed silica thickener, and stir to obtain a high-temperature resistant metal surface coating.

[0033] Regarding the high-temperature resistance test method of the high-temperature resistant metal surface coating prepared in the above respective embodiments, it comprises the following contents: Step 1: Thermogravimetric analysis. Place the metal specimen coated with the coating into the sample cell of a thermogravimetric analyzer, and conduct the test under a nitrogen atmosphere. Set the heating rate to 10 °C / min, and the temperature range to 30 - 800 °C. Record the weight change of the sample during the heating process, and focus on observing the initial decomposition temperature, decomposition rate, and the remaining weight percentage at the target high temperature. The higher the initial decomposition temperature, the slower the decomposition rate, and the higher the remaining weight percentage at the target high temperature, the better the high-temperature resistance performance of the coating.

[0034] Step 2: High-temperature hardness test. Place the metal specimen coated with the coating into a high-temperature furnace, and set the temperature gradients of the high-temperature furnace to 200 °C, 400 °C, 600 °C, and 800 °C. After the temperature stabilizes at the set value, use a high-temperature hardness tester (Rockwell hardness tester) to measure the hardness of the coating surface. Take the average value after measuring 5 times at each temperature point, and record the change of the hardness value with temperature. The smaller the decrease in the hardness value at high temperature, the better the structural stability of the coating at high temperature and the stronger the high-temperature resistance performance.

[0035] Regarding the test method for the anti-aging performance of the high-temperature resistant metal surface coatings prepared in the above embodiments, it includes the following content: Place the coated sample into a xenon lamp aging test chamber, set the light intensity to 0.55 W / m²・nm at a wavelength of 340 nm, the blackboard temperature to 63 °C, the relative humidity to 50%, and the rainfall cycle to spray water for 18 minutes every 120 minutes. Take out the sample every 200 hours, and observe the changes on the coating surface, such as color change, powdering, cracking, etc. At the same time, use a glossmeter to measure the glossiness change of the coating surface, a color difference meter to measure the color change, and an adhesion tester to measure the change of the coating adhesion. As the aging time increases, if the glossiness decreases slightly, the color change is small, and the adhesion remains good, it indicates that the anti-aging performance of the coating is excellent.

[0036] Regarding the test method for the anti-corrosion performance of the high-temperature resistant metal surface coatings prepared in the above embodiments, it includes the following content Place the treated specimen into a salt spray test chamber, and conduct a salt spray test according to the standard specified test cycles (such as 240 hours, 480 hours, 720 hours, etc.). After the test is completed, take out the specimen, rinse it clean with water, observe whether there are corrosion phenomena (such as rust spots, blisters, peeling, etc.) on the coating surface, and evaluate the anti-corrosion performance of the coating according to the corrosion degree (such as the percentage of the corrosion area in the total area). At the same time, an electrochemical workstation can be used to conduct electrochemical impedance spectroscopy (EIS) tests on the specimen, and the protective performance of the coating can be evaluated by analyzing the impedance spectrum diagram. The higher the impedance value, the better the anti-corrosion performance of the coating.

[0037] The performance comparison charts of the metal surface coatings prepared in the above three embodiments are as follows:

[0038] The high-temperature resistant and corrosion-resistant coating in the above chart is a common high-temperature resistant and corrosion-resistant coating on the market. According to the above test results, the coating prepared in this case has good performance in terms of high-temperature resistance, anti-aging and corrosion resistance, and among them, the metal surface coating prepared according to the preparation process in Example 3 has better performance in all aspects.

[0039] Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art and related fields without creative efforts shall fall within the scope of protection of the present invention. The structures, devices and operation methods not specifically described and explained in the present invention shall be implemented by conventional means in the art without special instructions and limitations.

Claims

1. A high temperature resistant metal surface coating, characterized in that: The invention comprises the following components by weight: ceramic silicone resin: 40-60 parts, polyethersulfone modified organic fluorine resin: 20-30 parts, water-based polyimide resin: 8-10 parts, zinc chrome yellow: 10-15 parts, boron nitride: 4-6 parts, modified phenolic amine curing agent: 3-5 parts, barium sulfate: 8-15 parts, short-cut carbon fiber: 8-10 parts, hollow glass microspheres: 5-8 parts, silane coupling agent: 2-4 parts, organic silicon defoaming agent: 1-3 parts, dispersant: 8-12 parts, thickener: 1-2 parts, composite coating anti-aging agent: 6-9 parts; The specific preparation method of the composite coating anti-aging agent is as follows: Step 1: Dry the nano zinc oxide in a vacuum drying oven to remove moisture, and then perform ultrafine grinding treatment, and grind 4-hydroxybenzophenone, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole and a composite hindered amine light stabilizer in a ball mill respectively; Step 2: Add acrylic resin into a reaction kettle, add 5%-8% ethyl acetate as a solvent, stir, add 4-hydroxybenzophenone, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole and composite hindered amine light stabilizer, nano zinc oxide, antioxidant and dispersant treated in step 1 into the reaction kettle, and continue stirring; Step 3: using an ultrasonic disperser to perform ultrasonic dispersion treatment on the mixture in the reaction kettle; Step 4: Remove the solvent from the ultrasonically dispersed mixture by vacuum distillation, and cool to room temperature to obtain a composite coating anti-aging agent after the solvent is removed.

2. A high temperature resistant metal surface coating according to claim 1, characterized in that: The silane coupling agent is bis-[γ-(triethoxysilyl)propyl]tetrasulfide, and the thickener is a fumed silica thickener.

3. The high temperature resistant metal surface coating according to claim 1, characterized in that: The specific preparation method of the composite hindered amine light stabilizer in step 1 is as follows: Step A1: adding tetrahydrodicyclopentadienylamine and potassium carbonate catalyst into a reaction kettle, and bromoalkane under nitrogen protection, and after the reaction is completed, cooling, filtering and washing to obtain hindered amine compound A; Step A2: adding hydrogen siloxane and tetramethylpiperidinamine derivative into a reaction container, adding chloroplatinic acid catalyst, heating and stirring to obtain hindered amine compound B; Step A3: first add the carrier resin phenolic modified epoxy resin into the mixer, start stirring, add antioxidant 1010, ultraviolet absorber and dispersant in sequence, then add hindered amine compound A and hindered amine compound B in sequence, and continue stirring after the addition is completed; Step A4: the uniformly mixed material is extruded and granulated through a twin-screw extruder, and the extruded material is cooled and pelletized to obtain composite hindered amine light stabilizer particles.

4. The high temperature resistant metal surface coating according to claim 3, characterized in that: The ultraviolet absorber in step A3 is a triazine derivative, and the dispersant in step A3 is polyethylene wax.

5. The high temperature resistant metal surface coating according to claim 1, characterized in that: The composite coating anti-aging agent comprises the following components by weight: 12-15 parts of 4-hydroxybenzophenone, 12-14 parts of 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole, 18-20 parts of hindered amine light stabilizer, 14-16 parts of nano zinc oxide, 35-45 parts of acrylic resin, 1-2.5 parts of antioxidant and 0.8-1.6 parts of dispersant.

6. A method for preparing a high temperature resistant metal surface coating, characterized in that: The method comprises the following preparation steps: Step S1: ceramic silicone resin, polyethersulfone modified organic fluorine resin and water-based polyimide resin are placed in a reaction kettle, heated, and stirred to obtain a mixed resin A; boron nitride, barium sulfate, and short-cut carbon fibers are placed in a vacuum drying oven respectively, and after drying, they are ground using a grinding device, filtered and set aside, and the hollow glass microspheres are preheated first; Step S2: In a reaction kettle equipped with a high-speed disperser, a heating device, and a temperature control monitoring and speed regulation system, xylene and n-butanol are mixed in a volume ratio of 3:1 to obtain a solvent, and the boron nitride, barium sulfate, chopped carbon fibers, and hollow glass microspheres pretreated in step S1 are added, and a dispersant is added; Step S3: pouring the mixed resin A pretreated in step S1 into the reaction kettle; Step S4: In a reaction kettle, a silane coupling agent, an organosilicon defoaming agent, and a composite coating anti-aging agent are added in sequence, and finally a thickener is added, and the mixture is stirred to obtain a high temperature resistant metal surface coating.

7. The method for preparing a high temperature resistant metal surface coating according to claim 6, characterized in that: The total amount of the mixed solvent of toluene and n-butanol in step S2 is 15-20% of the total amount of the resin.

8. The method for preparing a high temperature resistant metal surface coating according to claim 6, characterized in that: The temperature control monitoring and speed regulation system in step S2 has the following control method: Step 1: Initialize the system and set the temperature control parameters and speed control parameters; Step 2: Preheating of hollow glass microspheres; Step 3: Filler addition and high-speed dispersion.

9. The method for preparing a high temperature resistant metal surface coating according to claim 8, characterized in that: The working process of the heating device control system in the second step is as follows: Step B1: During the heating process, a high-precision temperature sensor monitors the temperature of the solvent and material mixture system in the reactor. The temperature sensor transmits the real-time collected temperature data to the controller in the form of an electrical signal. After receiving the temperature data, the controller processes and analyzes it and compares the actual temperature with the set target temperature range. Step B2: When the actual temperature is lower than the lower limit of the target temperature, the controller issues a command to increase the heating power. The heating device may use a resistance wire heating method, and the controller adjusts the heating power. Step B3: When the temperature reaches the target temperature range, the heating device control system enters the temperature maintenance stage, during which the controller monitors the temperature change and fine-tunes the heating power; Step B4, the temperature sensor is used as a feedback element to feed back the temperature information in the reactor to the controller in real time. The controller compares the temperature feedback data with the set temperature and calculates the temperature deviation. If the temperature deviation exceeds ±2°C, the controller adjusts the heating power.

10. The method for preparing a high temperature resistant metal surface coating according to claim 9, characterized in that: The algorithm preset by the controller in step B2 is as follows: The temperature range of the entire heating process is divided into multiple intervals. Assuming the lower limit of the target temperature is T1 and the upper limit is T2, the intervals can be divided as follows; Low temperature range: T0 to T1- T1; Medium temperature range: T1- T1 to T2 - T2; High temperature range: T2- T2 to T2; In the low temperature range, the initial heating power is set to P0, and the heating power in this range increases by P1, that is, the first heating power is adjusted to P0+ P1, the second heating power is adjusted to P0+2 P1; In the medium temperature range, if the temperature rises by 1°C, the increase in heating power decreases P2, when the temperature rises from T1- When T1 starts to rise, the heating power increases by = P1- P2; As the temperature continues to rise, let the current temperature be T, T1- T1<T<T2- T2, heating power increase The calculation formula is = P1- P2 (T-(T1- T1)); In the high temperature range, when the temperature enters the high temperature range, the increase in heating power is extremely small and approaches zero. At T2, the heating power increase rate decreases to P3; At temperatures from T2- T2 rises to T2, assuming the current temperature is T, T2- T2<T<T2, heating power increase Further reduce, The calculation formula is = P3- P4 (T-(T2- T2)), where P4 is the amplitude value that is further reduced in the high temperature range.

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