An insulating anti-pollution flashover coating and a preparation method thereof

Abstract

The application relates to the technical field of paint, and discloses an insulating anti-pollution flashover paint and a preparation method thereof.The paint comprises, by weight, 40-50 parts of hydroxyl-terminated polydimethylsiloxane, 10-15 parts of hydroxypropyl fluorosiloxane, 4-6 parts of imidazolyl phosphorus-containing polymer, 1-3 parts of silane coupling agent, 2-3 parts of talcum powder, 0.1-1 part of ultraviolet light absorber UV-327, 0.1-0.5 part of antioxidant 1010, 2-3 parts of methyl tributyl ketoxime silane, and 0.05-0.1 part of dibutyl tin dilaurate catalyst.The long-acting low-surface-energy hydrophobic system is constructed by using the hydroxypropyl fluorosiloxane, the self-made imidazolyl phosphorus-containing polymer is introduced to realize the multiple synergistic effects of halogen-free flame retardation, antibacterial and antifouling, weather resistance and reinforcement, and the prepared paint has the excellent hydrophobic antifouling performance, environmental protection flame retardation, weather resistance and aging resistance, electrical insulation and mechanical adhesion.

Description

Technical Field

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

[0002] The safe operation of power transmission and transformation equipment is directly related to the stability and reliability of the power system. Pollution flashover is one of the main causes of external insulation failure in power transmission and transformation equipment. In environments with industrial pollution, coastal salt spray, and sandstorms, a layer of contaminants adheres to the surface of insulators. When exposed to humid weather such as fog, dew, or drizzle, the electrolytes in the contaminant layer dissolve, leading to a significant decrease in the insulation performance of the insulator surface, an increase in leakage current, and ultimately, a pollution flashover trip, causing a large-scale power outage.

[0003] Currently, room temperature vulcanizing (RTV) silicone rubber coatings are the mainstream anti-flashover coatings for insulators. Due to their excellent hydrophobic properties and hydrophobic migration, they can effectively improve the flashover voltage of insulators and are widely used in the power industry. However, existing anti-flashover coatings still have many shortcomings: First, they lack long-term effectiveness. After long-term outdoor operation, the hydrophobic properties of the coating rapidly decline, hydrophobic migration decreases, and the anti-flashover effect is significantly reduced, typically requiring recoating every 3-5 years. Second, they have poor weather resistance. Under environments such as ultraviolet radiation, acid rain, and high / low temperature cycling, they are prone to problems such as chalking, cracking, peeling, and decreased adhesion, failing to meet the requirements of long-term outdoor operation. Third, they suffer from an imbalance in overall performance. Adding halogenated flame retardants to improve flame retardancy results in poor environmental performance, and the nanofillers are prone to agglomeration, leading to a mismatch between the coating's mechanical strength, insulation performance, and anti-pollution performance.

[0004] Therefore, developing an insulating and anti-fouling coating that combines long-lasting hydrophobicity and anti-fouling properties, excellent weather resistance and anti-aging properties, high insulation and arc resistance, strong mechanical adhesion, environmental friendliness and flame retardancy, and convenient construction is an urgent technical problem to be solved in this field. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art, the present invention aims to provide an insulating anti-pollution flashover coating and its preparation method, which has good anti-pollution, weather resistance and anti-aging, and high insulation effects.

[0006] To achieve the above objectives, the present invention provides the following technical solution: an insulating and anti-flashover coating, comprising the following weight components: 40-50 parts by weight of hydroxyl-terminated polydimethylsiloxane, 10-15 parts by weight of hydroxypropyl fluorosiloxane, 4-6 parts by weight of imidazole-based phosphorus-containing polymer, 1-3 parts by weight of silane coupling agent, 2-3 parts by weight of talc, 0.1-1 parts by weight of ultraviolet absorber UV-327, 0.1-0.5 parts by weight of antioxidant 1010, 2-3 parts by weight of methyl tributanone oxime silane, and 0.05-0.1 parts by weight of dibutyltin dilaurate catalyst;

[0007] The hydroxyl-terminated polydimethylsiloxane has a viscosity of 10,000-50,000 mPa at 25°C. s.

[0008] Preferably, the preparation method of the imidazole-based phosphorus-containing polymer is as follows: S1. Under a nitrogen atmosphere, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and 4-maleimide benzoic acid were added to N,N-dimethylformamide solvent, stirred and mixed, heated to 85-90℃ and kept at that temperature for 1-2 h, and then heated to 125-130℃ and reacted for 6-9 h. After the reaction was completed, the mixture was cooled to room temperature, and then distilled water was added and recrystallized in an ice-water bath for 10-12 h. The mixture was then filtered under reduced pressure, washed with petroleum ether, and dried to obtain intermediate 1. S2. Add undecenol and intermediate 1 to N,N-dimethylformamide solvent, stir to dissolve, continue to add p-toluenesulfonic acid catalyst, react at 90-95℃ for 4-6h, after which distill under reduced pressure, wash and dry to obtain alkenyl-modified phosphorus-containing maleimide; S3. Add bromododecane and N-vinylimidazole to a reactor containing ethyl acetate and reflux at 60-65°C for 20-24 h. After the reaction, wash the ethyl acetate precipitate, remove the solvent by vacuum distillation, and dry to obtain alkenylated quaternary ammonium salt imidazole. S4. Dissolve 2-3 mmol of alkenylated quaternary ammonium salt imidazole, 2-4 mmol of alkenyl-modified phosphorus-containing maleimide, 1-1.5 mmol of acrylic acid, 1-2 mmol of hexafluorobutyl methacrylate, 0.8-1 mmol of acryloyloxytriisopropylsilane, and 0.08-0.1 mmol of dodecathiol chain transfer agent in 40-55 mL of N,N-dimethylformamide solvent, stir and mix, add to a reactor, purge with nitrogen for protection, heat to 75-85 °C, then add 0.04-0.06 mmol of azobisisobutyronitrile initiator dropwise. After the addition is complete, maintain the temperature for reaction, and after completion, rotary evaporate to obtain imidazole-based phosphorus-containing polymer.

[0009] Preferably, in S1, the ratio of N,N-dimethylformamide, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and 4-maleimide benzoic acid is 30-40 mL: 5-7 mmol: 5-7 mmol.

[0010] Preferably, in S2, the ratio of undecenol, intermediate 1, N,N-dimethylformamide, and p-toluenesulfonic acid catalyst is 4-6 mmol: 5-8 mmol: 35-45 mL: 0.01-0.02 mmol.

[0011] Preferably, in S3, the ratio of bromododecane, N-vinylimidazole, and ethyl acetate is 4-7 mmol: 6-15 mmol: 40-50 mL.

[0012] Preferably, in step S4, the heat preservation reaction time is 4-6 hours.

[0013] Preferably, the silane coupling agent is one of KH-550, KH-560, and KH-570.

[0014] Preferably, it includes the following steps: Step 1: Add hydroxyl-terminated polydimethylsiloxane and hydroxypropyl fluorosiloxane to a sealed reactor. Stir at room temperature for 20-30 minutes under a vacuum of -0.06 to -0.08 MPa until homogeneous to obtain a base mixture. Continue to add imidazole-based phosphorus-containing polymer, silane coupling agent, talc, UV absorber UV-327, and antioxidant 1010 to the mixture and stir to obtain a slurry. Step 2: Add methyl tributanone oxime silane to the mixed slurry, stir for 20-30 minutes, then add dibutyltin dilaurate catalyst, continue vacuum stirring for 15-20 minutes, after which vacuum degassing, and vulcanize at room temperature for 24 hours to obtain an insulating anti-flashover coating.

[0015] Compared with the prior art, the present invention has the following beneficial technical effects: This invention uses hydroxyl-terminated polydimethylsiloxane as the base resin for the coating and combines it with hydroxypropyl fluorinated siloxane to construct a long-lasting low surface energy hydrophobic system. The low surface energy of fluorine and the flexible Si-O backbone of siloxane work together to form a stable hydrophobic interface on the coating surface, which greatly improves the water contact angle and hydrophobic migration of the coating. This solves the problem of rapid degradation of hydrophobic performance of traditional RTV coatings after long-term outdoor operation and extends the effective service life of the coating.

[0016] In the imidazole-based phosphorus-containing polymer of this invention, phosphaphenanthrene flame-retardant groups, maleimide heat-resistant groups, imidazole quaternary ammonium salt antibacterial groups, fluorinated hydrophobic groups, and siloxane adhesion-promoting groups are integrated into the same polymer molecular chain, achieving multiple synergistic effects of halogen-free flame retardancy, antibacterial and antifouling properties, weather resistance and reinforcement, and hydrophobic insulation. Firstly, the phosphaphenanthrene groups and maleimide groups work together to form a dense carbonized protective layer in the condensed phase, playing a flame-retardant role. Excellent flame-retardant effect can be achieved without adding halogenated flame retardants, taking into account both environmental protection and flame retardancy. Secondly, the imidazole quaternary ammonium salt cationic groups endow the coating with long-lasting antibacterial and antifouling properties, which can inhibit the growth of microorganisms and molds on the surface of insulators, reduce the adhesion of organic pollutants, and further enhance the anti-flashover effect. Thirdly, the siloxane groups and fluorocarbon groups in the polymer molecular chain can form good compatibility with the matrix resin, avoiding the problem of inorganic filler agglomeration, while improving the adhesion between the coating and the insulator substrate, high and low temperature resistance, and weather resistance and anti-aging properties.

[0017] This invention uses methyl tributanone oxime silane as a crosslinking agent, combined with dibutyltin dilaurate catalyst, to achieve room temperature curing of the coating. This allows for convenient application without the need for high-temperature curing, making it suitable for spraying applications on insulators of power transmission and transformation equipment. The insulating and anti-flashover coating prepared by this invention simultaneously possesses excellent long-lasting hydrophobic anti-flashover properties, environmentally friendly halogen-free flame retardant properties, excellent weather resistance and anti-aging properties, high electrical insulation properties, and strong mechanical adhesion. It overcomes the technical shortcomings of traditional anti-flashover coatings, such as insufficient long-term effectiveness, poor weather resistance, and unbalanced overall performance. It can be widely used for external insulation protection of insulators in power transmission and transformation equipment, significantly improving the safety and stability of power grid operation. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] 9,10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide: CAS, 35948-25-5.

[0020] 4-Maleiminobenzoic acid: CAS, 17057-04-4.

[0021] KH-550: 3-aminopropyltriethoxysilane.

[0022] KH-560: γ-glycidoxypropyltrimethoxysilane.

[0023] KH-570: γ-methacryloyloxypropyltrimethoxysilane.

[0024] Preparation of Hydroxypropyl Fluorinated Siloxanes: Zheng Chunsen et al., Coatings Industry, Vol. 46, No. 9, 2016, "Research on Waterborne Photocurable Polyurethane Emulsion Modified by Fluorinated Organosilicon and Epoxy Composites". 20g D4, 7g BHTS, and 0.02g dimethyl phthalate (DMT) were added to a four-necked flask equipped with a stirrer and thermometer. The mixture was stirred until homogeneous at a certain temperature (approximately 30 min). A certain amount of lithium silanol catalyst was added, and the temperature was raised to the reaction temperature. 11.95g D3F was slowly added dropwise, and the reaction was allowed to proceed for 5 h. A certain amount of phosphoric acid was added as a stop agent. After the reaction was completed, methanol was used as a precipitant for multiple extractions to remove small cyclic molecule byproducts from the product system, yielding hydroxypropyl fluorinated siloxanes.

[0025] Example 1 An insulating anti-flashover coating comprises the following components by weight: 40 parts by weight of hydroxyl-terminated polydimethylsiloxane, 10 parts by weight of hydroxypropyl fluorosiloxane, 4 parts by weight of imidazole-based phosphorus-containing polymer, 1 part by weight of silane coupling agent, 2 parts by weight of talc, 0.1 parts by weight of ultraviolet absorber UV-327, 0.1 parts by weight of antioxidant 1010, 2 parts by weight of methyl tributanone oxime silane, and 0.05 parts by weight of dibutyltin dilaurate catalyst; The silane coupling agent is KH-550.

[0026] The hydroxyl-terminated polydimethylsiloxane has a viscosity of 10000 mPa at 25°C. s.

[0027] The preparation method of the imidazole-based phosphorus-containing polymer is as follows: S1. Under a nitrogen atmosphere, 5 mmol of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and 5 mmol of 4-maleimide benzoic acid were added to 30 mL of N,N-dimethylformamide solvent. The mixture was stirred and heated to 85 °C for 1 h, and then heated to 125 °C for 6 h. After the reaction was completed, the mixture was cooled to room temperature, and then recrystallized in distilled water in an ice-water bath for 10 h. The mixture was then filtered under reduced pressure, washed with petroleum ether, and dried to obtain intermediate 1. S2. Add 4 mmol of undecenol and 5 mmol of intermediate 1 to 35 mL of N,N-dimethylformamide solvent, stir to dissolve, and continue to add 0.01 mmol of p-toluenesulfonic acid catalyst. React at 90 °C for 4 h. After the reaction is completed, distill under reduced pressure, wash and dry to obtain alkenyl-modified phosphorus-containing maleimide. S3. Add 4 mmol of bromododecane and 6 mmol of N-vinylimidazole to a reactor containing 40 mL of ethyl acetate, reflux at 60 °C for 20 h, wash the ethyl acetate precipitate after the reaction, remove the solvent by vacuum distillation, and dry to obtain alkenylated quaternary ammonium salt imidazole. S4. Dissolve 2 mmol of alkenylated quaternary ammonium salt imidazole, 2 mmol of alkenyl-modified phosphorus-containing maleimide, 1 mmol of acrylic acid, 1 mmol of hexafluorobutyl methacrylate, 0.8 mmol of acryloyloxytriisopropylsilane, and 0.08 mmol of dodecathiol chain transfer agent in 40 mL of N,N-dimethylformamide solvent, stir and mix, add to a reactor, purge with nitrogen for protection, heat to 75 °C, then add 0.04 mmol of azobisisobutyronitrile initiator dropwise. After the addition is complete, keep the reaction at this temperature for 4 h, and then rotary evaporate to obtain imidazole-based phosphorus-containing polymer.

[0028] Preparation method of insulating anti-flashover coating: Step 1: Add hydroxyl-terminated polydimethylsiloxane and hydroxypropyl fluorosiloxane to a sealed reactor. Stir at room temperature for 20 minutes under a vacuum of -0.06 MPa until homogeneous to obtain a base mixture. Continue to add imidazole-based phosphorus-containing polymer, silane coupling agent, talc, UV absorber UV-327, and antioxidant 1010 to the mixture and stir to obtain a slurry. Step 2: Add methyl tributanone oxime silane to the mixed slurry, stir for 20 minutes, then add dibutyltin dilaurate catalyst, continue vacuum stirring for 15 minutes, after which vacuum degassing, and vulcanize at room temperature for 24 hours to obtain an insulating anti-flashover coating.

[0029] Example 2 An insulating anti-flashover coating comprises the following components by weight: 45 parts by weight of hydroxyl-terminated polydimethylsiloxane, 12.5 parts by weight of hydroxypropyl fluorosiloxane, 5 parts by weight of imidazole-based phosphorus-containing polymer, 2 parts by weight of silane coupling agent, 2.5 parts by weight of talc, 0.55 parts by weight of UV absorber UV-327, 0.3 parts by weight of antioxidant 1010, 2.5 parts by weight of methyl tributanone oxime silane, and 0.075 parts by weight of dibutyltin dilaurate catalyst; The silane coupling agent is KH-560.

[0030] The hydroxyl-terminated polydimethylsiloxane has a viscosity of 30,000 mPa at 25°C. s.

[0031] The preparation method of the imidazole-based phosphorus-containing polymer is as follows: S1. Under a nitrogen atmosphere, 6 mmol of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and 6 mmol of 4-maleimide benzoic acid were added to 35 mL of N,N-dimethylformamide solvent. The mixture was stirred and heated to 87 °C for 2 h, and then heated to 128 °C for 7 h. After the reaction was completed, the mixture was cooled to room temperature, and then recrystallized in distilled water in an ice-water bath for 11 h. The mixture was then filtered under reduced pressure, washed with petroleum ether, and dried to obtain intermediate 1. S2. Add 5 mmol of undecenol and 6.5 mmol of intermediate 1 to 40 mL of N,N-dimethylformamide solvent, stir to dissolve, and continue to add 0.015 mmol of p-toluenesulfonic acid catalyst. React at 92 °C for 5 h. After the reaction is completed, distill under reduced pressure, wash and dry to obtain alkenyl-modified phosphorus-containing maleimide. S3. Add 5.5 mmol of bromododecane and 10.5 mmol of N-vinylimidazole to a reactor containing 45 mL of ethyl acetate, reflux at 62 °C for 22 h, wash the ethyl acetate precipitate after the reaction, remove the solvent by vacuum distillation, and dry to obtain alkenylated quaternary ammonium salt imidazole. S4. Dissolve 2.5 mmol of alkenylated quaternary ammonium salt imidazole, 3 mmol of alkenyl-modified phosphorus-containing maleimide, 1.2 mmol of acrylic acid, 1.5 mmol of hexafluorobutyl methacrylate, 0.9 mmol of acryloyloxytriisopropylsilane, and 0.09 mmol of dodecathiol chain transfer agent in 47 mL of N,N-dimethylformamide solvent, stir and mix, add to a reactor, purge with nitrogen for protection, heat to 80 °C, then add 0.056 mmol of azobisisobutyronitrile initiator dropwise. After the addition is complete, maintain the temperature for 5 h, and then rotary evaporate to obtain imidazole-based phosphorus-containing polymer.

[0032] Preparation method of insulating anti-flashover coating: Step 1: Add hydroxyl-terminated polydimethylsiloxane and hydroxypropyl fluorinated siloxane to a sealed reactor. Stir at room temperature for 25 minutes under a vacuum of -0.07 MPa until homogeneous to obtain a base mixture. Continue to add imidazole-based phosphorus-containing polymer, silane coupling agent, talc, UV absorber UV-327, and antioxidant 1010 to the mixture and stir to obtain a slurry. Step 2: Add methyl tributanone oxime silane to the mixed slurry, stir for 25 min, then add dibutyltin dilaurate catalyst, continue vacuum stirring for 17 min, after which vacuum degassing, and vulcanize at room temperature for 24 h to obtain an insulating anti-flashover coating.

[0033] Example 3 An insulating anti-flashover coating comprises the following components by weight: 50 parts by weight of hydroxyl-terminated polydimethylsiloxane, 15 parts by weight of hydroxypropyl fluorosiloxane, 6 parts by weight of imidazole-based phosphorus-containing polymer, 3 parts by weight of silane coupling agent, 3 parts by weight of talc, 1 part by weight of ultraviolet absorber UV-327, 0.5 parts by weight of antioxidant 1010, 3 parts by weight of methyl tributanone oxime silane, and 0.1 parts by weight of dibutyltin dilaurate catalyst; The silane coupling agent is KH-570.

[0034] The hydroxyl-terminated polydimethylsiloxane has a viscosity of 50,000 mPa at 25°C. s.

[0035] The preparation method of the imidazole-based phosphorus-containing polymer is as follows: S1. Under a nitrogen atmosphere, 7 mmol of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and 7 mmol of 4-maleimide benzoic acid were added to 40 mL of N,N-dimethylformamide solvent. The mixture was stirred and heated to 90 °C for 2 h, and then heated to 130 °C for 9 h. After the reaction was completed, the mixture was cooled to room temperature, and then recrystallized in distilled water in an ice-water bath for 12 h. The mixture was then filtered under reduced pressure, washed with petroleum ether, and dried to obtain intermediate 1. S2. Add 6 mmol of undecenol and 8 mmol of intermediate 1 to 45 mL of N,N-dimethylformamide solvent, stir to dissolve, and continue to add 0.02 mmol of p-toluenesulfonic acid catalyst. React at 95 °C for 6 h. After the reaction is completed, distill under reduced pressure, wash and dry to obtain alkenyl-modified phosphorus-containing maleimide. S3. Add 7 mmol of bromododecane and 15 mmol of N-vinylimidazole to a reactor containing 50 mL of ethyl acetate, reflux at 65 °C for 24 h, wash the ethyl acetate precipitate after the reaction, remove the solvent by vacuum distillation, and dry to obtain alkenylated quaternary ammonium salt imidazole. S4. Dissolve 3 mmol of alkenylated quaternary ammonium salt imidazole, 4 mmol of alkenyl-modified phosphorus-containing maleimide, 1.5 mmol of acrylic acid, 2 mmol of hexafluorobutyl methacrylate, 1 mmol of acryloyloxytriisopropylsilane, and 0.1 mmol of dodecathiol chain transfer agent in 55 mL of N,N-dimethylformamide solvent, stir and mix, add to a reactor, purge with nitrogen for protection, heat to 85 °C, then add 0.06 mmol of azobisisobutyronitrile initiator dropwise. After the addition is complete, maintain the temperature for 6 h, and then rotary evaporate to obtain imidazole-based phosphorus-containing polymer.

[0036] Preparation method of insulating anti-flashover coating: Step 1: Add hydroxyl-terminated polydimethylsiloxane and hydroxypropyl fluorosiloxane to a sealed reactor. Stir at room temperature for 30 minutes under a vacuum of -0.08 MPa until homogeneous to obtain a base mixture. Continue to add imidazole-based phosphorus-containing polymer, silane coupling agent, talc, UV absorber UV-327, and antioxidant 1010 to the mixture and stir to obtain a slurry. Step 2: Add methyl tributanone oxime silane to the mixed slurry, stir for 30 min, then add dibutyltin dilaurate catalyst, continue vacuum stirring for 20 min, after which vacuum degassing, and vulcanize at room temperature for 24 h to obtain an insulating anti-flashover coating.

[0037] Comparative Example 1 The difference between this comparative example and Example 3 is that hydroxypropyl fluorosiloxane is not added, and an equal amount of terminal hydroxyl polydimethylsiloxane is used instead.

[0038] Comparative Example 2 The difference between this comparative example and Example 3 is that 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is used instead of the imidazole-based phosphorus-containing polymer.

[0039] Comparative Example 3 The difference between this comparative example and Example 3 is that hexafluorobutyl methacrylate was not added in S4 during the preparation of the imidazole-based phosphorus-containing polymer, while the remaining preparation steps, material ratios, coating formulations, and preparation methods remained the same.

[0040] The performance tests of the embodiments and comparative samples of this invention were conducted using the following standards: 1. The hydrophobicity / hydrophobicity test of the coating surface shall be conducted in accordance with GB / T24622-2022 "Guideline for Measurement of Hydrophobicity of Insulator Surface"; 2. The artificial pollution flashover voltage test shall be conducted in accordance with GB / T4585-2024 "Artificial Pollution Test for High Voltage Porcelain and Glass Insulators for AC Systems"; 3. Volume resistivity testing shall be conducted in accordance with GB / T31838.5-2021 "Dielectric and resistive properties of solid insulating materials - Part 5: Resistive properties (DC method) - Volume resistivity and volume resistivity of impregnated and coated materials"; 4. Breakdown strength testing shall be conducted in accordance with GB / T1408.1-2016 "Electrical strength test methods for insulating materials - Part 1: Tests at power frequency"; 5. Adhesion testing shall be conducted in accordance with GB / T9286-2021 "Paints and Varnishes - Cross-cut Test"; 6. The limiting oxygen index test for flame retardant performance shall be conducted in accordance with GB / T2406.2-2009; 7. Artificial accelerated aging tests can refer to GB / T14522-2008 "Artificial Climate Aging Test Methods for Plastics, Coatings and Rubber Materials Used in Machinery Industry - Fluorescent Ultraviolet Lamp".

[0041] 8. Antibacterial testing shall be conducted in accordance with GB / T21866-2025.

[0042] Table 1: Performance Test Results of Coatings in Examples and Comparative Examples

[0043] As shown in Table 1, in Comparative Example 1, hydroxypropyl fluorosiloxane was replaced by an equal amount of terminal hydroxyl polydimethylsiloxane. Hydroxypropyl fluorosiloxane is the core of the coating's long-lasting low surface energy hydrophobic system. Its fluoroalkyl segments can significantly reduce the surface energy of the coating and form a stable hydrophobic interface. At the same time, the fluorine group can synergize with the fluorocarbon groups in the imidazole-based phosphorus-containing polymer to improve the coating's density and aging resistance. After the removal of hydroxypropyl fluorosiloxane, the coating relies solely on the weak hydrophobic properties of the matrix siloxane and cannot form an effective hydrophobic film. Not only is the hydrophobic and antifouling performance lost, but the coating density also decreases, making it easier for moisture and ultraviolet rays to penetrate, leading to a chain reaction of degradation in insulation, adhesion, aging resistance, flame retardancy, and other properties. Comparative Example 2: Replacing the imidazole-based phosphorus-containing polymer with DOPO. The imidazole-based phosphorus-containing polymer of the present invention is not a simple phosphorus-based flame retardant, but a multifunctional core component integrating halogen-free flame retardancy, antibacterial and antifouling properties, weather resistance and reinforcement, interfacial compatibility, and hydrophobic synergy. Its molecular chain integrates phosphorus phenanthrene flame retardant groups, imidazole quaternary ammonium salt antibacterial groups, maleimide heat-resistant groups, fluorinated hydrophobic groups, and siloxane adhesion groups. Each group works together to achieve multiple functions. In contrast, DOPO alone only has basic phosphorus-based flame retardant effects and lacks antibacterial, heat-resistant, interfacial bonding, and hydrophobic synergy functions. It cannot form synergy with the matrix resin and fluorine-based components, and therefore cannot achieve effective flame retardancy. In addition, due to the decrease in system compatibility, it will lead to microstructural defects in the coating, resulting in a comprehensive decline in hydrophobic, insulating, adhesion, and aging resistance properties. Comparative Example 3: In step S4 of the preparation of the imidazole-based phosphorus-containing polymer, hexafluorobutyl methacrylate was not added. Hexafluorobutyl methacrylate is a key raw material for introducing fluorinated hydrophobic groups into the imidazole-based phosphorus-containing polymer. It forms a synergistic effect of difluoro groups with hydroxypropyl fluorinated siloxane in the coating system, which jointly improves the hydrophobic properties of the coating surface and the internal density. After its removal, the imidazole-based phosphorus-containing polymer loses the hydrophobic function of the fluorinated group and relies only on the single fluorinated group effect of the hydroxypropyl fluorinated siloxane. The hydrophobic synergistic effect is lost, the surface energy of the coating increases, the hydrophobic and antifouling properties decrease, and the density of the coating decreases, making it easier for ultraviolet rays and moisture to penetrate, resulting in a slight decrease in insulation, flame retardancy, adhesion, and aging resistance. Since the other functional groups of the imidazole-based phosphorus-containing polymer are not changed, the antibacterial properties only decrease slightly and do not show the complete failure as in Comparative Example 2.

[0044] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0045] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An insulating and anti-flashover coating, characterized in that, It includes the following components by weight: 40-50 parts by weight of hydroxyl-terminated polydimethylsiloxane, 10-15 parts by weight of hydroxypropyl fluorosiloxane, 4-6 parts by weight of imidazole-based phosphorus-containing polymer, 1-3 parts by weight of silane coupling agent, 2-3 parts by weight of talc, 0.1-1 parts by weight of ultraviolet absorber UV-327, 0.1-0.5 parts by weight of antioxidant 1010, 2-3 parts by weight of methyl tributanone oxime silane, and 0.05-0.1 parts by weight of dibutyltin dilaurate catalyst; The hydroxyl-terminated polydimethylsiloxane has a viscosity of 10,000-50,000 mPa at 25°C. s.

2. The insulating and anti-flashover coating according to claim 1, characterized in that, The preparation method of the imidazole-based phosphorus-containing polymer is as follows: S1. Under a nitrogen atmosphere, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and 4-maleimide benzoic acid were added to N,N-dimethylformamide solvent, stirred and mixed, heated to 85-90℃ and kept at that temperature for 1-2 h, and then heated to 125-130℃ and reacted for 6-9 h. After the reaction was completed, the mixture was cooled to room temperature, and then distilled water was added and recrystallized in an ice-water bath for 10-12 h. The mixture was then filtered under reduced pressure, washed with petroleum ether, and dried to obtain intermediate 1. S2. Add undecenol and intermediate 1 to N,N-dimethylformamide solvent, stir to dissolve, continue to add p-toluenesulfonic acid catalyst, react at 90-95℃ for 4-6h, after which distill under reduced pressure, wash and dry to obtain alkenyl-modified phosphorus-containing maleimide; S3. Add bromododecane and N-vinylimidazole to a reactor containing ethyl acetate and reflux at 60-65°C for 20-24 h. After the reaction, wash the ethyl acetate precipitate, remove the solvent by vacuum distillation, and dry to obtain alkenylated quaternary ammonium salt imidazole. S4. Dissolve 2-3 mmol of alkenylated quaternary ammonium salt imidazole, 2-4 mmol of alkenyl-modified phosphorus-containing maleimide, 1-1.5 mmol of acrylic acid, 1-2 mmol of hexafluorobutyl methacrylate, 0.8-1 mmol of acryloyloxytriisopropylsilane, and 0.08-0.1 mmol of dodecathiol chain transfer agent in 40-55 mL of N,N-dimethylformamide solvent, stir and mix, add to a reactor, purge with nitrogen for protection, heat to 75-85 °C, then add 0.04-0.06 mmol of azobisisobutyronitrile initiator dropwise. After the addition is complete, maintain the temperature for reaction, and after completion, rotary evaporate to obtain imidazole-based phosphorus-containing polymer.

3. The insulating and anti-flashover coating according to claim 2, characterized in that, In S1, the ratio of N,N-dimethylformamide, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and 4-maleimide benzoic acid is 30-40 mL: 5-7 mmol: 5-7 mmol.

4. The insulating and anti-flashover coating according to claim 2, characterized in that, In S2, the ratio of undecenol, intermediate 1, N,N-dimethylformamide, and p-toluenesulfonic acid catalyst is 4-6 mmol: 5-8 mmol: 35-45 mL: 0.01-0.02 mmol.

5. The insulating and anti-flashover coating according to claim 2, characterized in that, In S3, the ratio of bromododecane, N-vinylimidazole, and ethyl acetate is 4-7 mmol: 6-15 mmol: 40-50 mL.

6. The insulating and anti-flashover coating according to claim 2, characterized in that, In the S4 process, the heat preservation reaction time is 4-6 hours.

7. The insulating and anti-flashover coating according to claim 1, characterized in that, The silane coupling agent is one of KH-550, KH-560, and KH-570.

8. A method for preparing an insulating anti-flashover coating as described in any one of claims 1-7, characterized in that, Includes the following steps: Step 1: Add hydroxyl-terminated polydimethylsiloxane and hydroxypropyl fluorosiloxane to a sealed reactor. Stir at room temperature for 20-30 minutes under a vacuum of -0.06 to -0.08 MPa until homogeneous to obtain a base mixture. Continue to add imidazole-based phosphorus-containing polymer, silane coupling agent, talc, UV absorber UV-327, and antioxidant 1010 to the mixture and stir to obtain a slurry. Step 2: Add methyl tributanone oxime silane to the mixed slurry, stir for 20-30 minutes, then add dibutyltin dilaurate catalyst, continue vacuum stirring for 15-20 minutes, after which vacuum degassing, and vulcanize at room temperature for 24 hours to obtain an insulating anti-flashover coating.

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