A high solid content high dielectric performance charged spray insulation coating and a preparation method and application thereof

Abstract

The application discloses a kind of high solid content high dielectric performance charged spray insulating paint and preparation method and application, the paint includes: polysiloxane 70-100 parts, reinforcing filler 20-30 parts, calcium carbonate 20-40 parts, mercapto boron nitride 10-30 parts, alumina 10-20 parts, flame retardant 30-50 parts, catalyst 0.3-1 part, curing agent 3-10 parts, coupling agent 1-5 parts, solvent 20-100 parts, liquid reinforcing agent 5-15 parts;Polysiloxane includes mass ratio 1-1.5:3-9 of high, low viscosity polysiloxane.The preparation method is as follows: after high, low viscosity polysiloxane and reinforcing filler, calcium carbonate, mercapto boron nitride, alumina, flame retardant are mixed, curing agent, coupling agent, solvent, liquid reinforcing agent are added, finally catalyst is added and filtered, and it is prepared.The application improves the thermal conductivity of silicone rubber, dielectric property and insulating property, and has better part corner coverage.

Description

Technical Field

[0001] This invention relates to an insulating coating for electrical equipment, its preparation method, and its application, and more particularly to a high-solids-content, high-dielectric-performance electrically conductive sprayable insulating coating, its preparation method, and its application. Background Technology

[0002] In the power system, due to the wide range and long duration of power outages caused by grid pollution flashover accidents, the safe operation of transmission and transformation equipment is seriously threatened, resulting in huge economic losses. Therefore, grid pollution flashover has always been an important issue that has hindered the development of the power industry. How to effectively solve the problem of grid pollution flashover has become an important task to ensure the safe production of the power system.

[0003] Live-line spraying, because it can be performed while the equipment is energized, does not rely on power outage windows like traditional maintenance. Therefore, its scheduling is independent of other projects that require power outages, avoiding the strain on limited power outage resources. Furthermore, the work area is located within the operating equipment zone, avoiding overlap with the densely packed space of power-outage maintenance sites. This effectively isolates the work from other trades in both time and space, greatly improving the flexibility and safety of maintenance work. Moreover, live-line spraying can be carried out under favorable weather conditions, ensuring the quality of the coating.

[0004] In power systems, composite external insulation refers to an external insulation structure that uses organic polymer materials (mainly silicone rubber) as the core insulating component, replacing traditional porcelain or glass insulators. In existing technologies, anti-flashover coatings are applied to the composite external insulation via live-line spraying, serving to protect and enhance insulation performance. Therefore, the promotion and application of live-line spraying anti-flashover coating technology has broad social benefits and significant economic value.

[0005] However, silicone rubber is prone to aging, and its dielectric properties decline with age. Current anti-flashover coatings suffer from core defects such as poor mechanical properties, easy aging, and slow recovery of hydrophobicity. The matrix material itself has low strength, requiring reinforcement with fillers, but this easily leads to filler agglomeration and cracking. In harsh environments such as high humidity and heavy industrial areas, the coating is prone to adhesion failure, acid and alkali corrosion, and hardening and brittleness. After long-term operation, under the influence of ultraviolet radiation and thermal shock, peeling, powdering, and loss of hydrophobicity occur, with slow recovery and decreased dielectric strength after aging. Furthermore, existing coatings have low solids content, and low-solids coatings, after gelation, cannot effectively cover the edges and corners of components, resulting in exposed metal and reduced insulation. Summary of the Invention

[0006] Purpose of the invention: The purpose of this invention is to provide a high-dielectric-content, high-dielectric-performance sprayable insulating coating that effectively covers the edges and corners of components;

[0007] The second objective of this invention is to provide a method for preparing the above-mentioned high-solids-content, high-dielectric-performance electrically conductive sprayable insulating coating; the third objective of this invention is to provide the application of the above-mentioned high-solids-content, high-dielectric-performance electrically conductive sprayable insulating coating.

[0008] Technical Solution: The high-solids-content, high-dielectric-performance electrostatic sprayable insulating coating of the present invention comprises, by weight, the following components: 70-100 parts polysiloxane, 20-30 parts reinforcing filler, 20-40 parts calcium carbonate, 10-30 parts mercapto-boron nitride, 10-20 parts alumina, 30-50 parts flame retardant, 0.3-1 part catalyst, 3-10 parts curing agent, 1-5 parts coupling agent, 20-100 parts solvent, and 5-15 parts liquid reinforcing agent; the polysiloxane is a high-viscosity polysiloxane with a viscosity of 5000-7000 cs and a low-viscosity polysiloxane with a viscosity of 500-1000 cs, and the mass ratio of the high-viscosity polysiloxane to the low-viscosity polysiloxane is 1-1.5:3-9. The polysiloxane is at least one of hydrogen-terminated polysiloxane, methoxyvinyl polysiloxane, methoxyfluorinated polysiloxane, methoxydimethylsiloxane, and hydroxyl-terminated polydimethylsiloxane; more preferably, it is at least one of methoxydimethylsiloxane, hydroxyl-terminated polydimethylsiloxane, and methoxyvinyl polysiloxane.

[0009] The reinforcing filler is at least one of titanium dioxide, aluminum hydroxide, iron hydroxide, silica, silicon carbide, alumina, aluminum nitride, calcined gypsum, boron nitride, silicon carbide, kaolin, silica fume, asbestos wool, or calcium carbonate.

[0010] The flame retardant is preferably aluminum hydroxide.

[0011] The curing agent is one or more of methyltrimethoxysilane, methyltributyl ketone oxime silane, ethyltrimethoxysilane, phenyltrimethoxysilane, vinyltrimethoxysilane, aniline methyltrimethoxysilane, diethylamine methyltrimethoxysilane, and propyltrimethoxysilane.

[0012] The coupling agent is one or more of γ-aminopropyltriethoxysilane, mercaptosilane coupling agent, γ-glycidoxypropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane.

[0013] The catalyst is at least one of platinum catalyst, titanate, dibutyltin dilaurate, and stannous octoate.

[0014] The solvent is a composite solvent HY-Z, manufactured by Jinan Huaying Chemical Co., Ltd.

[0015] The liquid reinforcing agent is at least one of methyl MQ silicone resin, methyl vinyl MQ silicone resin, methyl phenyl MQ silicone resin, and long-chain alkyl MQ silicone resin.

[0016] The preparation method of the above-mentioned high-solids-content, high-dielectric-performance electrically sprayable insulating coating includes the following steps:

[0017] The polysiloxane is a mixture of high-viscosity polysiloxane with a viscosity of 5000-7000 cs and low-viscosity polysiloxane with a viscosity of 500-1000 cs.

[0018] Add reinforcing filler, calcium carbonate, mercapto-boron nitride, aluminum oxide, and flame retardant to the uniformly mixed polysiloxane, and knead and stir under heating conditions;

[0019] Add curing agent, coupling agent, solvent, and liquid reinforcing agent to the well-stirred mixture, stir, and obtain the initial mixed adhesive;

[0020] The catalyst was added to the initial mixed adhesive, stirred, and a composite adhesive was obtained. After filtration, a high-solids-content, high-dielectric-performance electrostatic spray anti-flashover coating was obtained.

[0021] The mass ratio of high-viscosity polysiloxane to low-viscosity polysiloxane is 1-1.5:3-9.

[0022] Among them, the mixture is kneaded and stirred for 4-6 hours under heating conditions of 80-100℃.

[0023] The thiolized boron nitride is obtained through the following steps:

[0024] Boron nitride was hydroxylated in a sodium hydroxide solution or a concentrated nitric acid solution, washed until neutral, and dried to obtain hydroxylated boron nitride.

[0025] The solution of ethanol and water was adjusted to acidity, then mercaptosilane coupling agent was added, heated, and refluxed. After cooling, hydroxylated boron nitride was added, stirred, filtered, and washed to obtain mercaptolated boron nitride.

[0026] In this process, boron nitride is mixed with a sodium hydroxide solution with a concentration of 1.5-3 mol / L at a ratio of m:V = 1:20-1:50, and the mixture is melted and reacted at a temperature of 80-100℃ for 8-12 hours.

[0027] Acetic acid is added to a mixture of ethanol and water to adjust the pH of the solution to 4-5. Then, a mercaptosilane coupling agent is added, and the mixture is heated to 60-80℃ and refluxed for 2-3 hours. After cooling, hydroxylated boron nitride is added, and the mixture is ultrasonically dispersed in a nitrogen atmosphere and stirred for 4-8 hours. The mixture is then filtered and washed to obtain mercaptolated boron nitride.

[0028] The mercaptosilane coupling agent is at least one selected from mercaptoethyltriethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-mercaptopropylmethyldimethoxysilane. The above-mentioned high-solids-content, high-dielectric-performance electrically conductive sprayable insulating coating is used in power system insulation equipment.

[0029] Invention Principle: Under high electric fields, many breakdowns are "thermal breakdowns," caused by localized overheating. Based on this principle, improving thermal conductivity can improve dielectric properties and breakdown resistance. Boron nitride has excellent thermal conductivity and resistivity, making it a good material; however, boron nitride has poor interfacial compatibility with silicone rubber, easily leading to agglomeration and accumulation. This not only fails to effectively utilize the reinforcing effect of boron nitride but also severely affects the mechanical strength and performance of silicone rubber. This invention improves the thermal conductivity, dielectric properties, and insulation properties of silicone rubber by grafting mercapto-modified boron nitride onto it.

[0030] Beneficial effects: Compared with the prior art, the present invention achieves the following significant effects:

[0031] (1) This invention combines high-viscosity polysiloxane, low-viscosity polysiloxane and mercapto boron nitride to graft mercapto boron nitride onto silicone rubber, thereby improving the thermal conductivity, dielectric properties and insulation properties of silicone rubber. Moreover, the formulation of this coating reduces the proportion of reinforcing filler while increasing the proportion of calcium carbonate, which can reduce the overall viscosity with less impact on performance, thereby reducing the proportion of solvent and increasing the solid content of the coating, thus effectively covering the edges and corners of the components and extending the external insulation life of power equipment. (2) In terms of preparation process, the surface of boron nitride is first pretreated with hydroxylation to introduce reactive sites, and then chemical grafting is carried out using silane coupling agent as "molecular bridge": firstly, hydroxyl groups are introduced on the surface and edges of boron nitride by strong alkaline treatment, and then reacted with a specific silane coupling agent to graft organic functional groups onto the surface of boron nitride, which can undergo co-vulcanization reaction with silicone rubber matrix to form the strongest interfacial bond, significantly improving thermal conductivity and tensile strength; by enhancing the interfacial compatibility and chemical bonding between filler and matrix, uniform dispersion of boron nitride in silicone rubber is achieved, so that the composite material achieves synergistic improvement in thermal conductivity, mechanical and hydrophobic properties. (3) The coating of the present invention improves the rheological properties of the system, and the material exhibits good thixotropy and wettability during construction or molding. This allows the coating or potting compound to adhere tightly to the surface of power equipment, especially at sharp points, corners and edges, forming a uniform and air-gap-free protective layer, which greatly improves the risk of local defects caused by uneven physical blending. Detailed Implementation

[0032] The present invention will now be described in further detail.

[0033] Example 1

[0034] The high-solids-content, high-dielectric-performance sprayable insulating coating provided in this embodiment comprises, by weight, the components shown in Table 1:

[0035] Table 1 Specific components of Example 1

[0036]

[0037] This thiolized boron nitride was prepared by the following steps:

[0038] (1) Nano-sized boron nitride (hereinafter referred to as BN) with a size of about 500 nm was placed in a 2 mol / L sodium hydroxide solution for hydroxylation modification. The specific process is as follows: BN and 2 mol / L NaOH solution were mixed at a mass:volume ratio of 1:30 and melted at a temperature of 90℃ for 10 h; then washed with deionized water until neutral, and baked at a high temperature of 105℃ to remove moisture, so as to obtain hydroxylated boron nitride.

[0039] (2) Mix ethanol and deionized water in a mass ratio of 9:1 and add them to a flask. Then add acetic acid to adjust the pH of the solution to 4-5, and then add 3-mercaptopropyltrimethoxysilane. Heat to 80°C and reflux for 2 hours. After cooling, add hydroxylated boron nitride. After ultrasonic dispersion in a nitrogen atmosphere, stir for 4 hours. Filter the solvent, wash with ethanol and distilled water to obtain mercaptolated boron nitride.

[0040] The preparation method of this high-solids-content, high-dielectric-performance electrically sprayable insulating coating includes the following steps:

[0041] (1) Take high-viscosity polysiloxane with a viscosity of 5000-7000cs and low-viscosity polysiloxane with a viscosity of 500-1000cs and mix them in a mass ratio of 1.5:8.5;

[0042] (2) Take 100 parts of the mixed polysiloxane, add 25 parts of reinforcing filler silica, 30 parts of calcium carbonate, 15 parts of mercapto boron nitride, 15 parts of alumina and 50 parts of aluminum hydroxide, and knead and stir at 100℃ for 4 hours.

[0043] (3) Add 6 parts of methyl tributanone oxime silane, 1.5 parts of γ-glycidyl etheroxypropyltrimethoxysilane, 0.75 parts of γ-aminopropyltriethoxysilane, 150 parts of high flash point composite solvent HY-Z purchased from Jinan Huaying Chemical Co., Ltd., and 5 parts of methyl MQ silicone resin to the mixture after stirring, and stir evenly.

[0044] (4) Add 0.3 parts of dibutyltin dilaurate to the initial mixed glue, stir, and obtain composite glue. Finally, filter to obtain a charged spray anti-flashover coating with high solid content and high dielectric properties.

[0045] Example 2

[0046] The high-solids-content, high-dielectric-performance sprayable insulating coating provided in this embodiment comprises, by weight, the components shown in Table 2:

[0047] Table 2 Specific components of Example 2

[0048]

[0049] This thiolized boron nitride was prepared by the following steps:

[0050] (1) The boron nitride nanoparticles with a size of about 500 nm were placed in a 2 mol / L sodium hydroxide solution for hydroxylation modification. The specific process was as follows: BN was mixed with 2 mol / L NaOH solution at a mass:volume ratio of 1:30 and melted at a temperature of 90 °C for 10 h; then washed with deionized water until neutral, and then baked at a high temperature of 105 °C to remove moisture, thus obtaining hydroxylated boron nitride.

[0051] (2) Mix ethanol and deionized water in a mass ratio of 9:1 and add them to a flask. Then add acetic acid to adjust the pH of the solution to 4-5, and then add 3-mercaptopropyltrimethoxysilane. Heat to 80°C and reflux for 2 hours. After cooling, add hydroxylated boron nitride. After ultrasonic dispersion in a nitrogen atmosphere, stir for 4 hours. Filter the solvent, wash with ethanol and distilled water to obtain mercaptolated boron nitride.

[0052] The preparation method of this high-solids-content, high-dielectric-performance electrically sprayable insulating coating includes the following steps:

[0053] (1) Take high-viscosity polysiloxane with a viscosity of 5000-7000cs and low-viscosity polysiloxane with a viscosity of 500-1000cs and mix them in a mass ratio of 1.5:8.5;

[0054] (2) Take 100 parts of the mixed polysiloxane, add 25 parts of reinforcing filler silica, 30 parts of calcium carbonate, 20 parts of mercapto boron nitride, 15 parts of alumina and 50 parts of aluminum hydroxide, and knead and stir at 100℃ for 4 hours.

[0055] (3) Add 6 parts of methyl tributanone oxime silane, 1.5 parts of γ-glycidyl etheroxypropyltrimethoxysilane, 0.75 parts of γ-aminopropyltriethoxysilane, 150 parts of high flash point composite solvent HY-Z purchased from Jinan Huaying Chemical Co., Ltd., and 5 parts of methyl MQ silicone resin to the mixture after stirring, and stir evenly.

[0056] (4) Add 0.3 parts of dibutyltin dilaurate to the initial mixed glue, stir, and obtain composite glue. Finally, filter to obtain a charged spray anti-flashover coating with high solid content and high dielectric properties.

[0057] Example 3

[0058] The high-solids-content, high-dielectric-performance sprayable insulating coating provided in this embodiment comprises, by weight, the components shown in Table 3:

[0059] Table 3 Specific components of Example 3

[0060]

[0061] This thiolized boron nitride was prepared by the following steps:

[0062] (1) The boron nitride nanoparticles with a size of about 500 nm were placed in a 2 mol / L sodium hydroxide solution for hydroxylation modification. The specific process was as follows: BN was mixed with 2 mol / L NaOH solution at a mass:volume ratio of 1:30 and melted at a temperature of 90 °C for 10 h; then washed with deionized water until neutral, and then baked at a high temperature of 105 °C to remove moisture, thus obtaining hydroxylated boron nitride.

[0063] (2) Mix ethanol and deionized water in a mass ratio of 9:1 and add them to a flask. Then add acetic acid to adjust the pH of the solution to 4-5, and then add 3-mercaptopropyltrimethoxysilane. Heat to 80°C and reflux for 2 hours. After cooling, add hydroxylated boron nitride. After ultrasonic dispersion in a nitrogen atmosphere, stir for 4 hours. Filter the solvent, wash with ethanol and distilled water to obtain mercaptolated boron nitride.

[0064] The preparation method of this high-solids-content, high-dielectric-performance electrically sprayable insulating coating includes the following steps:

[0065] (1) Take high-viscosity polysiloxane with a viscosity of 5000-7000cs and low-viscosity polysiloxane with a viscosity of 500-1000cs and mix them in a mass ratio of 1.5:8.5;

[0066] (2) Take 100 parts of the mixed polysiloxane, add 25 parts of reinforcing filler silica, 30 parts of calcium carbonate, 25 parts of mercapto boron nitride, 15 parts of alumina and 50 parts of aluminum hydroxide, and knead and stir at 100℃ for 4 hours.

[0067] (3) Add 6 parts of methyl tributanone oxime silane, 1.5 parts of γ-glycidyl etheroxypropyltrimethoxysilane, 0.75 parts of γ-aminopropyltriethoxysilane, 150 parts of high flash point composite solvent HY-Z purchased from Jinan Huaying Chemical Co., Ltd., and 5 parts of methyl MQ silicone resin to the mixture after stirring, and stir evenly.

[0068] (4) Add 0.3 parts of dibutyltin dilaurate to the initial mixed adhesive, stir for 5 minutes to obtain the composite adhesive, and finally filter to obtain a charged spray anti-flashover coating with high solid content and high dielectric properties.

[0069] Example 4

[0070] The high-solids-content, high-dielectric-performance sprayable insulating coating provided in this embodiment comprises, by weight, the components shown in Table 4:

[0071] Table 4 Specific components of Example 4

[0072]

[0073] This thiolized boron nitride was prepared by the following steps:

[0074] (1) The boron nitride nanoparticles with a size of about 500 nm were placed in a 2 mol / L sodium hydroxide solution for hydroxylation modification. The specific process was as follows: BN was mixed with 2 mol / L NaOH solution at a mass:volume ratio of 1:30 and melted at a temperature of 90 °C for 10 h; then washed with deionized water until neutral, and then baked at a high temperature of 105 °C to remove moisture, thus obtaining hydroxylated boron nitride.

[0075] (2) Mix ethanol and deionized water in a mass ratio of 9:1 and add them to a flask. Then add acetic acid to adjust the pH of the solution to 4-5, and then add 3-mercaptopropyltrimethoxysilane. Heat to 80°C and reflux for 2 hours. After cooling, add hydroxylated boron nitride. After ultrasonic dispersion in a nitrogen atmosphere, stir for 4 hours. Filter the solvent, wash with ethanol and distilled water to obtain mercaptolated boron nitride.

[0076] The preparation method of this high-solids-content, high-dielectric-performance electrically sprayable insulating coating includes the following steps:

[0077] (1) Take high-viscosity polysiloxane with a viscosity of 5000-7000cs and low-viscosity polysiloxane with a viscosity of 500-1000cs and mix them in a mass ratio of 1.5:8.5.

[0078] (2) Take 100 parts of the mixed polysiloxane, add 25 parts of reinforcing filler silica, 30 parts of calcium carbonate, 30 parts of mercapto boron nitride, 15 parts of alumina and 50 parts of aluminum hydroxide, and knead and stir at 100℃ for 4 hours.

[0079] (3) Add 6 parts of methyl tributanone oxime silane, 1.5 parts of γ-glycidyl etheroxypropyltrimethoxysilane, 0.75 parts of γ-aminopropyltriethoxysilane, 150 parts of high flash point composite solvent HY-Z purchased from Jinan Huaying Chemical Co., Ltd., and 5 parts of methyl MQ silicone resin to the mixture after stirring, and stir evenly.

[0080] (4) Add 0.3 parts of dibutyltin dilaurate to the initial mixed glue, stir, and obtain composite glue. Finally, filter to obtain a charged spray anti-flashover coating with high solid content and high dielectric properties.

[0081] Example 5

[0082] The high-solids-content, high-dielectric-performance sprayable insulating coating provided in this embodiment comprises, by weight, the components shown in Table 5:

[0083] Table 5 Specific components of Example 5

[0084]

[0085] This thiolized boron nitride was prepared by the following steps:

[0086] (1) The boron nitride nanoparticles with a size of about 500 nm were placed in a 2 mol / L sodium hydroxide solution for hydroxylation modification. The specific process was as follows: BN was mixed with 2 mol / L NaOH solution at a mass:volume ratio of 1:30 and melted at a temperature of 90 °C for 10 h; then washed with deionized water until neutral, and then baked at a high temperature of 105 °C to remove moisture, thus obtaining hydroxylated boron nitride.

[0087] (2) Mix ethanol and deionized water at a mass ratio of 9:1 and add them to a flask. Add acetic acid to adjust the pH of the solution to 4-5, then add 3-mercaptopropyltrimethoxysilane, heat to 80°C, reflux for 2 hours, cool, and then add hydroxylated boron nitride. After ultrasonic dispersion in a nitrogen atmosphere, stir for 4 hours, filter, wash with solvent, ethanol and distilled water to obtain mercaptolated boron nitride.

[0088] The preparation method of this high-solids-content, high-dielectric-performance electrically sprayable insulating coating includes the following steps:

[0089] (1) Take high-viscosity polysiloxane with a viscosity of 5000-7000cs and low-viscosity polysiloxane with a viscosity of 500-1000cs and mix them in a mass ratio of 1.5:8.5.

[0090] (2) Take 100 parts of the mixed polysiloxane, add 25 parts of reinforcing filler silica, 30 parts of calcium carbonate, 25 parts of mercapto boron nitride, 15 parts of alumina and 50 parts of aluminum hydroxide, and knead and stir at 100℃ for 4 hours.

[0091] (3) Add 9 parts of methyl tributanone oxime silane, 1.5 parts of γ-glycidyl etheroxypropyltrimethoxysilane, 0.75 parts of γ-aminopropyltriethoxysilane, 150 parts of high flash point composite solvent HY-Z purchased from Jinan Huaying Chemical Co., Ltd., and 5 parts of methyl MQ silicone resin to the mixture after stirring, and stir evenly.

[0092] (4) Add 0.3 parts of dibutyltin dilaurate to the initial mixed glue, stir, and obtain composite glue. Finally, filter to obtain a charged spray anti-flashover coating with high solid content and high dielectric properties.

[0093] Comparative Example 1

[0094] Unlike Example 3, thiolized boron nitride was omitted.

[0095] Comparative Example 2

[0096] Unlike Example 3, the mercaptolated boron nitride and aluminum oxide are omitted, and the aluminum hydroxide is changed from 50 parts to 35 parts.

[0097] Comparative Example 3

[0098] Unlike Example 3, the viscosity of the polysiloxane is 5000-7000 cs.

[0099] Comparative Example 4

[0100] Unlike Example 3, the viscosity of the polysiloxane is 500-1000 cs.

[0101] Comparative Example 5

[0102] Unlike Example 3, the boron nanonitride is not modified; that is, the mercapto boron nitride is replaced with boron nanonitride.

[0103] Comparative Example 6

[0104] Unlike Example 3, the thiolized boron nitride was replaced with modified boron nitride obtained by ball milling boron nitride with glucose as the medium. In this modification process, mechanical force induces the breakage of B-N bonds at the edge of boron nitride, generating active sites that react with the hydroxyl groups of glucose. Glucose molecules are covalently grafted onto the surface of boron nitride through B-O chemical bonds, transforming the surface functional groups of boron nitride into hydroxyl / glycosylated functional groups.

[0105] Comparative Example 7

[0106] Unlike Example 3, the amount of mercaptolated boron nitride was changed to 50 parts.

[0107] The test data for the above embodiments and comparative examples are shown in Table 6 below.

[0108] Table 6 Test data for each embodiment and comparative example

[0109]

[0110] Based on the results in Table 1 above, Comparative Example 1 shows that without the addition of mercapto-boron nitride, the overall performance is relatively low; Comparative Example 2 shows that without the addition of mercapto-boron nitride and with a reduction in filler, the overall performance is relatively low, and the dielectric properties are not improved; Comparative Example 3 shows that using only high-viscosity polysiloxane adhesive results in slightly lower overall performance, a slight increase in coating viscosity, and a 14% decrease in dielectric properties; Comparative Example 4 shows that using only low-viscosity polysiloxane adhesive results in a significant decrease in overall performance; Comparative Example 5 shows that using unmodified boron nitride results in a significant decrease in elongation; Comparative Example 6 shows that using glucose ball milling to obtain hydroxyl / glycosylated modified boron nitride does not show a significant improvement in overall performance; and Comparative Example 7 shows that an excessively high proportion of mercapto-boron nitride significantly reduces overall performance.

Claims

1. A high-solids-content, high-dielectric-performance electrically conductive sprayable insulating coating, characterized in that, The product comprises, by weight, the following components: 70-100 parts polysiloxane, 20-30 parts reinforcing filler, 20-40 parts calcium carbonate, 10-30 parts mercaptolated boron nitride, 10-20 parts alumina, 30-50 parts flame retardant, 0.3-1 part catalyst, 3-10 parts curing agent, 1-5 parts coupling agent, 20-100 parts solvent, and 5-15 parts liquid reinforcing agent; wherein the polysiloxane is a high-viscosity polysiloxane with a viscosity of 5000-7000 cs and a low-viscosity polysiloxane with a viscosity of 500-1000 cs, and the mass ratio of the high-viscosity polysiloxane to the low-viscosity polysiloxane is 1-1.5:3-9.

2. The high-solids-content, high-dielectric-performance electrically conductive sprayable insulating coating according to claim 1, characterized in that, The polysiloxane is at least one of the following: hydrogen-terminated polysiloxane, methoxyvinyl polysiloxane, methoxyfluorinated polysiloxane, methoxydimethylsiloxane, and hydroxyl-terminated polydimethylsiloxane.

3. The high-solids-content, high-dielectric-performance electrically conductive sprayable insulating coating according to claim 1, characterized in that, The reinforcing filler is at least one of titanium dioxide, aluminum hydroxide, iron hydroxide, silica, silicon carbide, alumina, aluminum nitride, calcined gypsum, boron nitride, silicon carbide, kaolin, silica fume, asbestos wool, or calcium carbonate; the curing agent is one or more of methyltrimethoxysilane, methyltributyl ketone oxime silane, ethyltrimethoxysilane, phenyltrimethoxysilane, vinyltrimethoxysilane, anilinemethyltrimethoxysilane, diethylaminemethyltrimethoxysilane, and propyltrimethoxysilane; the liquid reinforcing agent is at least one of methylMQ silicone resin, methylvinylMQ silicone resin, methylphenylMQ silicone resin, and long-chain alkylMQ silicone resin.

4. The high-solids-content, high-dielectric-performance electrically conductive sprayable insulating coating according to claim 1, characterized in that, The coupling agent is one or more of γ-aminopropyltriethoxysilane, mercaptosilane coupling agent, γ-glycidoxypropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, and N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane; the catalyst is at least one of platinum catalyst, titanate, dibutyltin dilaurate, and stannous octoate.

5. A method for preparing a high-solids-content, high-dielectric-performance electrically conductive sprayable insulating coating as described in any one of claims 1-4, characterized in that, Includes the following steps: The polysiloxane is a mixture of high-viscosity polysiloxane with a viscosity of 5000-7000 cs and low-viscosity polysiloxane with a viscosity of 500-1000 cs. Add reinforcing filler, calcium carbonate, mercapto-boron nitride, aluminum oxide, and flame retardant to the uniformly mixed polysiloxane, and knead and stir under heating conditions; Add curing agent, coupling agent, solvent, and liquid reinforcing agent to the well-stirred mixture, stir, and obtain the initial mixed adhesive; The catalyst was added to the initial mixed adhesive, stirred, and a composite adhesive was obtained. After filtration, a high-solids-content, high-dielectric-performance electrostatic spray anti-flashover coating was obtained.

6. The method for preparing the high-solids-content, high-dielectric-performance electrically sprayable insulating coating according to claim 5, characterized in that, The thiolized boron nitride is obtained through the following steps: Boron nitride was hydroxylated in sodium hydroxide solution or concentrated nitric acid solution, washed until neutral, and dried to obtain hydroxylated boron nitride. The solution of ethanol and water was adjusted to acidity, then mercaptosilane coupling agent was added, heated, and refluxed. After cooling, hydroxylated boron nitride was added, stirred, filtered, and washed to obtain mercaptolated boron nitride.

7. The high-solids-content, high-dielectric-performance electrically conductive sprayable insulating coating according to claim 6, characterized in that, The mercaptosilane coupling agent is at least one of mercaptoethyltriethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-mercaptopropylmethyldimethoxysilane.

8. The method for preparing the high-solids-content, high-dielectric-performance electrically sprayable insulating coating according to claim 6, characterized in that, Boron nitride was mixed with a sodium hydroxide solution with a concentration of 1.5–3 mol / L at a ratio of m:V = 1:20–1:50 and reacted with the solution at a temperature of 80–100℃ for 8–12 hours.

9. The method for preparing the high-solids-content, high-dielectric-performance electrically sprayable insulating coating according to claim 6, characterized in that, Acetic acid was added to a mixture of ethanol and water to adjust the pH of the solution to 4-5. Then, mercaptosilane coupling agent was added, and the mixture was heated to 60-80℃ and refluxed for 2-3 hours. After cooling, hydroxylated boron nitride was added, and the mixture was stirred for 4-8 hours. The mixture was then filtered and washed to obtain mercaptolated boron nitride.

10. The application of a high-solids-content, high-dielectric-performance sprayable insulating coating as described in any one of claims 1-4 in electrical system insulation equipment.

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