Silicone rubber-based composite insulator for high voltage power transmission and preparation method thereof

Abstract

The present invention relates to the field of rubber materials, specifically a silicone rubber-based composite insulator for high-voltage power transmission and a preparation method thereof. A silicone rubber-based composite insulator for high-voltage power transmission and a preparation method thereof, comprising the following steps: preparation of SiC-azodicarbonamide multilayer composite filler; preparation of silicone oil stabilizer; modification of SiC-azodicarbonamide multilayer composite filler; compounding and vulcanization of methylvinylphenyl silicone rubber. The present invention uses the characteristic that dopamine forms a polydopamine film when it meets an alkali, controls the time of adding SiC after adding a sodium hydroxide solution, so that azodicarbonamide adheres to the SiC surface during the formation of the polydopamine film, and then obtains a SiC-azodicarbonamide multilayer composite filler with many pores and a large specific surface area after a layer of SiC is attached by polydopamine, which can be better filled and compounded with methylvinylphenyl silicone rubber, so that the two are fully in contact and tightly connected, and the mechanical properties and thermal conductivity of the silicone rubber composite material are improved as a whole.

Description

Technical Field

[0001] The invention relates to the field of rubber materials, in particular to a silicone rubber-based composite insulator for high-voltage power transmission and a preparation method thereof. Background Art

[0002] Silicone rubber insulator is a composite device composed of a core rod, an umbrella skirt sheath and end fittings. It is installed between conductors and grounding components at different potentials. It has the advantages of ozone resistance, corona resistance, weather resistance, electrical insulation performance, good hydrophobicity, etc. Therefore, it is often used in overhead transmission lines to increase the creepage distance of overhead transmission lines.

[0003] The shed sheath in the silicone rubber insulator is made of silicone rubber material. Silicone rubber material has excellent hydrophobicity and high insulation, and can protect the insulator well. However, during the use of silicone rubber insulators, leakage tracking will occur, causing the temperature of the silicone rubber material to be too high and carbonized. In addition, due to the low mechanical strength of silicone rubber itself, it is easy to cause the material to be damaged, endangering the safety of equipment. Therefore, people often compound silicone rubber materials with other materials to improve their resistance to leakage tracking and mechanical properties.

[0004] At present, aluminum hydroxide is widely used as a flame retardant at home and abroad to improve the tracking resistance of silicone rubber composites. However, it is often necessary to fill a large amount of aluminum hydroxide in the silicone rubber composite to achieve a better effect, which also seriously affects the mechanical properties of the material. When aluminum hydroxide decomposes under heat, it often causes defects in the structure of the silicone rubber composite, which greatly reduces the durability of the silicone rubber composite.

[0005] In order to solve the above technical defects, the present invention has developed a durable silicone rubber-based composite insulator for high-voltage power transmission with excellent mechanical properties and anti-leakage tracking performance and a preparation method thereof. Summary of the invention

[0006] In order to solve the above technical defects, the present invention has developed a durable silicone rubber-based composite insulator for high-voltage power transmission with excellent mechanical properties and anti-leakage tracking performance and a preparation method thereof.

[0007] A method for preparing a silicone rubber-based composite insulator for high voltage power transmission comprises the following steps:

[0008] S1: Preparation of SiC-azodicarbonamide multilayer composite fillers;

[0009] S2: Preparation of silicone oil stabilizer;

[0010] S3: Modification of SiC-azodicarbonamide multilayer composite fillers;

[0011] S4: Compounding and vulcanization of methyl vinyl phenyl silicone rubber.

[0012] Furthermore, the preparation of the SiC-azodicarbonamide multilayer composite filler in step S1 comprises the following steps:

[0013] S1.1: Place 2-3 parts by weight of dopamine and 4-5 parts by weight of azodicarbonamide in a planetary ball mill, adjust the ball mill speed to 450-500 rpm, and ball mill for 4-6 hours to obtain a mixed material, place the mixed material in a container, add 15-20 parts by weight of deionized water, and stir for 10-15 minutes to obtain a mixed solution;

[0014] S1.2: Add sodium hydroxide solution to the mixed solution, adjust the pH to 8-9, let it stand for 4-5 minutes, then add 8-10 parts by weight of SiC powder, place the container in a vibrator, adjust the oscillation frequency to 100-120 times / minute, oscillate for 30-35 minutes, filter to obtain solid material I, rinse the solid material with deionized water 2-3 times, and then place it in an oven to dry at 85-90°C to obtain a preliminary composite filler;

[0015] S1.3: 18-20 parts by weight of deionized water are placed in a container, tris(hydroxymethyl)aminomethane is added until the pH value of the solution is 8.5-8.7 to obtain an alkaline buffer solution, 4-5 parts by weight of SiC powder and 0.8-1 parts by weight of sodium alginate are added to the alkaline buffer solution, stirred for 15-20 minutes, placed in an ultrasonic disperser, and subjected to ultrasonic treatment at a frequency of 60-80KHz for 25-30 minutes, then a preliminary composite filler and 1-2 parts by weight of dopamine are added, and then subjected to ultrasonic treatment at a frequency of 35-40KHz for 30-35 minutes, the container is sealed and placed in an oven, heated at a temperature of 70-75°C for 40-45 minutes, filtered, rinsed with deionized water 4-5 times, and dried at a temperature of 85-90°C to obtain a SiC-azodicarbonamide multilayer composite filler.

[0016] Furthermore, the preparation of the silicone oil stabilizer in step S2 comprises the following steps:

[0017] S2.1: Tetraethoxysilane, polydimethylsiloxane, vinyloxytrimethylsilane and hydrogen-containing double head are added into a container in a mass ratio of 1: (0.5-0.6): (0.8-1): (0.1-0.2), nitrogen is continuously introduced into the container for 10-15 minutes, and then toluene is added in a mass ratio of 1: (4-5) to the mixture in the container, stirred for 15-20 minutes, and then heated to 80-90 ° C, continued to stir for 3-4 hours, and filtered to obtain a filtrate;

[0018] S2.2: Place the filtrate in a vacuum distiller, control the vacuum pressure to 8000-10000 Pa, the distillation temperature to 55-60° C., and distill for 25-30 minutes to obtain a silicone oil stabilizer.

[0019] Furthermore, step S3, modification of SiC-azodicarbonamide multilayer composite filler, comprises the following steps:

[0020] S3.1: Add the silane coupling agent and deionized water to a container, stir and let stand for 40-45 minutes for hydrolysis to prepare a silane coupling agent aqueous solution with a concentration of 1-2%;

[0021] S3.2: Immerse the SiC-azodicarbonamide multilayer composite filler in the silane coupling agent aqueous solution for 8-10 minutes, filter and dry to obtain the silane-modified SiC-azodicarbonamide multilayer composite filler.

[0022] Further, step S4, compounding and vulcanization of methyl vinyl phenyl silicone rubber, comprises the following steps:

[0023] S4.1: 50-60 parts by weight of methyl vinyl phenyl silicone rubber are put into a kneader, 20-25 parts by weight of fumed silica, 6-8 parts by weight of silicone oil stabilizer and 0.02-0.03 parts by weight of 1-butynyl cyclohexanol are added, and the mixture is mixed evenly to obtain a mixed material;

[0024] S4.2: Add SiC-azodicarbonamide multilayer composite filler and 0.1-0.2 parts by weight of catalyst to the mixture, mix for 20-25 minutes, heat to 120-125°C, adjust the vacuum degree to 0.1-0.15Mpa for kneading and discharging to obtain a rubber material, place the rubber material in an open mill for open mixing for 1-2 hours, let it stand for 5-6 hours, add a vulcanizing agent for roller wrapping, pass it through 4-6 times, place it in a flat vulcanizer, adjust the temperature to 160-180°C, the pressure to 10-12Mpa, and vulcanize it for 2-3 hours to obtain a silicone rubber composite material;

[0025] S4.3: The hardware and epoxy glass fiber core rod are crimped, dried and preheated, and then coated with a coupling agent. The silicone rubber composite material is then molded, subjected to secondary vulcanization and quality inspection to obtain a silicone rubber-based composite insulator.

[0026] Furthermore, the particle size of the mixed material in step S1.1 is 50-100 nm.

[0027] Furthermore, the particle sizes of the SiC powder in step S1.2 and step S1.3 are 0.5-1 μm and 50-100 nm, respectively.

[0028] Furthermore, the model of the silane coupling agent in step S3.2 is KH-550.

[0029] Furthermore, the catalyst in step S4.2 is platinum.

[0030] A silicone rubber-based composite insulator for high-voltage power transmission is prepared by the above-mentioned method for preparing a silicone rubber-based composite insulator for high-voltage power transmission.

[0031] The beneficial effects are:

[0032] 1. The present invention uses the characteristic that dopamine forms a polydopamine film when it meets an alkali, controls the time of adding SiC after adding a sodium hydroxide solution, so that azodicarbonamide adheres to the SiC surface during the formation of the polydopamine film, and then obtains a SiC-azodicarbonamide multilayer composite filler with many pores and a large specific surface area after a layer of SiC is attached by polydopamine. The SiC-azodicarbonamide multilayer composite filler can be better filled and composited with methyl vinyl phenyl silicone rubber, so that the two are fully in contact and tightly connected, thereby improving the mechanical properties and thermal conductivity of the silicone rubber composite material as a whole;

[0033] 2. The present invention obtains a silicone rubber composite material by compounding SiC-azodicarbonamide multilayer composite filler with methyl vinyl phenyl silicone rubber, wherein azodicarbonamide has the characteristics of self-extinguishing and non-combustibility, good stability, and can decompose when the silicone rubber-based composite insulator reaches a certain temperature to generate a large amount of gas, thereby performing arc extinguishing and flame retardancy, thereby ensuring the tracking resistance of the silicone rubber composite material, and because azodicarbonamide is intercalated between SiC, the internal structure of the silicone rubber composite material will not be destroyed after decomposition, thereby ensuring that its mechanical properties and thermal conductivity will not decrease, making the material more durable;

[0034] 3. The present invention improves the compatibility of fumed silica and methyl vinyl phenyl silicone rubber by preparing a silicone oil stabilizer and adding it to the compounding process of methyl vinyl phenyl silicone rubber, thereby preventing the hydroxyl groups on the surface of fumed silica from reacting with the methyl vinyl phenyl silicone rubber during the compounding process, thereby hardening the rubber material and enhancing the mechanical properties of the silicone rubber composite material;

[0035] 4. By subjecting the SiC-azodicarbonamide multilayer composite filler to silane coupling treatment, a large number of amino groups are introduced on its surface, thereby reducing the hydrophilicity of the SiC-azodicarbonamide multilayer composite filler, greatly improving its compatibility with methyl vinyl phenyl silicone rubber, and further improving the structural stability of the silicone rubber composite material, making it more durable. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The present invention is a flow chart of a method for preparing a silicone rubber-based composite insulator for high-voltage power transmission adopted in an embodiment of the present invention. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Example 1

[0038] A method for preparing a silicone rubber-based composite insulator for high voltage power transmission, such as Figure 1 As shown, the following steps are included:

[0039] S1: The preparation of SiC-azodicarbonamide multilayer composite filler includes:

[0040] S1.1: 2 parts by weight of dopamine and 4 parts by weight of azodicarbonamide were placed in a planetary ball mill, the ball milling speed was adjusted to 450 rpm, and the ball milling was performed for 4 hours to obtain a mixture with a particle size of 50 nm. The mixture was placed in a container, 15 parts by weight of deionized water was added, and the mixture was stirred for 10 minutes to obtain a mixed solution;

[0041] S1.2: Add sodium hydroxide solution to the mixed solution, adjust the pH to 8, let it stand for 4 minutes, add 8 parts by weight of SiC powder with a particle size of 0.5 μm, place the container in a vibrator, adjust the oscillation frequency to 100 times / minute, oscillate for 30 minutes, filter to obtain solid material I, rinse the solid material twice with deionized water, and then place it in an oven for drying at a temperature of 85°C to obtain a preliminary composite filler;

[0042] S1.3: 18 parts by weight of deionized water are placed in a container, and tris(hydroxymethyl)aminomethane is added until the pH value of the solution is 8.5 to obtain an alkaline buffer solution. 4 parts by weight of SiC powder with a particle size of 50 nm and 0.8 parts by weight of sodium alginate are added to the alkaline buffer solution. After stirring for 15 minutes, the mixture is placed in an ultrasonic disperser and ultrasonically treated at a frequency of 60 kHz for 25 minutes. Then, a preliminary composite filler and 1 part by weight of dopamine are added, and ultrasonically treated at a frequency of 35 kHz for 30 minutes. The container is sealed and placed in an oven, and heated at a temperature of 70°C for 40 minutes. After filtering, the mixture is rinsed with deionized water 4 times, and dried at a temperature of 85°C to obtain a SiC-azodicarbonamide multilayer composite filler. The obtained SiC-azodicarbonamide multilayer composite filler has many gaps and a large specific surface area, and can be better filled and compounded with methyl vinyl phenyl silicone rubber, thereby improving the mechanical properties and thermal conductivity of the silicone rubber composite material as a whole.

[0043] S2: The preparation of silicone oil stabilizer includes:

[0044] S2.1: Tetraethoxysilane, polydimethylsiloxane, vinyloxytrimethylsilane and hydrogen-containing double head are added into a container in a mass ratio of 1:0.5:0.8:0.1, nitrogen is continuously introduced into the container for 10 minutes, and then toluene is added in a mass ratio of 1:5 to the mixture in the container, stirred for 15 minutes, and then heated to 80°C, stirred for 3 hours, and filtered to obtain a filtrate;

[0045] S2.2 Place the filtrate in a vacuum distiller, control the vacuum pressure to 8000Pa, the distillation temperature to 55°C, and distill for 25 minutes to obtain a silicone oil stabilizer, which is added to the compounding process of methyl vinyl phenyl silicone rubber to improve the compatibility of fumed silica and methyl vinyl phenyl silicone rubber, avoid the reaction of hydroxyl groups on the surface of fumed silica with methyl vinyl phenyl silicone rubber during the compounding process, harden the rubber, and enhance the mechanical properties of the silicone rubber composite material.

[0046] S3: Modification of SiC-azodicarbonamide multilayer composite filler includes:

[0047] S3.1: Mix KH-550 silane coupling agent and deionized water into a container, stir and let stand for 40 minutes for hydrolysis to prepare a 1.5% silane coupling agent aqueous solution;

[0048] S3.2: Immerse the SiC-azodicarbonamide multilayer composite filler in an aqueous solution of a silane coupling agent for 8 minutes, introduce a large number of amino groups on its surface, reduce the hydrophilicity of the SiC-azodicarbonamide multilayer composite filler, greatly improve its compatibility with methyl vinyl phenyl silicone rubber, further improve the structural stability of the silicone rubber composite material, and make it more durable. After filtering and drying, the silane-modified SiC-azodicarbonamide multilayer composite filler is obtained.

[0049] S4: Compounding and vulcanization of methyl vinyl phenyl silicone rubber includes:

[0050] S4.1: 50 parts by weight of methyl vinyl phenyl silicone rubber are put into a kneader, 20 parts by weight of fumed silica, 6 parts by weight of silicone oil stabilizer and 0.02 parts by weight of 1-butynyl cyclohexanol are added, and the mixture is mixed evenly to obtain a mixed material;

[0051] S4.2: Add SiC-azodicarbonamide multilayer composite filler and 0.1 parts by weight of platinum catalyst to the mixture, heat to 120°C after mixing for 20 minutes, adjust the vacuum degree to 0.1Mpa for kneading and discharging to obtain rubber, place the rubber in an open mill for 1 hour, let it stand for 5 hours, add dipentadienyl vulcanizer for roller coating, pass it through the thin mill 4 times, place it in a flat vulcanizer, adjust the temperature to 160°C, the pressure to 10Mpa, and vulcanize it for 2 hours to obtain a silicone rubber composite material, wherein azodicarbonamide has the characteristics of self-extinguishing and non-combustible, good stability, and can decompose when the silicone rubber-based composite insulator reaches a certain temperature to produce a large amount of gas, thereby extinguishing arc and flame retardant, ensuring the silicone rubber composite material's resistance to leakage tracking, and because azodicarbonamide is interspersed between SiC, it will not destroy the internal structure of the silicone rubber composite material after decomposition, thereby ensuring that its mechanical properties and thermal conductivity will not decrease, making the material more durable;

[0052] S4.3: The hardware and epoxy glass fiber core rod are crimped, dried and preheated, and then coated with a coupling agent. The silicone rubber composite material is then molded, subjected to secondary vulcanization and quality inspection to obtain a silicone rubber-based composite insulator. Example 2

[0053] A method for preparing a silicone rubber-based composite insulator for high voltage power transmission, such as Figure 1 As shown, the following steps are included:

[0054] S1: The preparation of SiC-azodicarbonamide multilayer composite filler includes:

[0055] S1.1: 3 parts by weight of dopamine and 5 parts by weight of azodicarbonamide were placed in a planetary ball mill, the ball milling speed was adjusted to 450 rpm, and the ball milling was performed for 4 hours to obtain a mixture with a particle size of 50 nm. The mixture was placed in a container, 20 parts by weight of deionized water were added, and the mixture was stirred for 10 minutes to obtain a mixed solution;

[0056] S1.2: Add sodium hydroxide solution to the mixed solution, adjust the pH to 8, let it stand for 4 minutes, add 10 parts by weight of SiC powder with a particle size of 0.5 μm, place the container in a vibrator, adjust the oscillation frequency to 100 times / minute, oscillate for 30 minutes, filter to obtain solid material I, rinse the solid material twice with deionized water, and then place it in an oven for drying at a temperature of 85°C to obtain a preliminary composite filler;

[0057] S1.3: Place 20 parts by weight of deionized water in a container, add tris(hydroxymethyl)aminomethane until the pH value of the solution is 8.5 to obtain an alkaline buffer solution, add 5 parts by weight of SiC powder with a particle size of 50 nm and 1 part by weight of sodium alginate to the alkaline buffer solution, stir for 15 minutes, place in an ultrasonic disperser, perform ultrasonic treatment at a frequency of 60 kHz for 25 minutes, then add preliminary composite filler and 2 parts by weight of dopamine, and perform ultrasonic treatment at a frequency of 35 kHz for 30 minutes, seal the container and place in an oven, heat at a temperature of 70°C for 40 minutes, filter, rinse with deionized water 4 times, and dry at a temperature of 85°C to obtain a SiC-azodicarbonamide multilayer composite filler. The obtained SiC-azodicarbonamide multilayer composite filler has many gaps and a large specific surface area, can be better filled and compounded with methyl vinyl phenyl silicone rubber, and the mechanical properties and thermal conductivity of the silicone rubber composite material are improved as a whole.

[0058] S2: The preparation of silicone oil stabilizer includes:

[0059] S2.1: Tetraethoxysilane, polydimethylsiloxane, vinyloxytrimethylsilane and hydrogen-containing double head are added into a container in a mass ratio of 1:0.6:1:0.2, nitrogen is continuously introduced into the container for 10 minutes, and then toluene is added in a mass ratio of 1:4 to the mixture in the container, stirred for 15 minutes, and then heated to 80°C, stirred for 3 hours, and filtered to obtain a filtrate;

[0060] S2.2: Place the filtrate in a vacuum distiller, control the vacuum pressure to 8000Pa, the distillation temperature to 55°C, and distill for 25 minutes to obtain a silicone oil stabilizer, which is added to the compounding process of methyl vinyl phenyl silicone rubber to improve the compatibility of fumed silica and methyl vinyl phenyl silicone rubber, avoid the reaction of hydroxyl groups on the surface of fumed silica with methyl vinyl phenyl silicone rubber during the compounding process, harden the rubber, and enhance the mechanical properties of the silicone rubber composite material.

[0061] S3: Modification of SiC-azodicarbonamide multilayer composite filler includes:

[0062] S3.1: Mix KH-550 silane coupling agent and deionized water into a container, stir and let stand for 40 minutes for hydrolysis to prepare a 2% silane coupling agent aqueous solution;

[0063] S3.2: Immerse the SiC-azodicarbonamide multilayer composite filler in an aqueous solution of a silane coupling agent for 8 minutes, introduce a large number of amino groups on its surface, reduce the hydrophilicity of the SiC-azodicarbonamide multilayer composite filler, greatly improve its compatibility with methyl vinyl phenyl silicone rubber, further improve the structural stability of the silicone rubber composite material, and make it more durable. After filtering and drying, the silane-modified SiC-azodicarbonamide multilayer composite filler is obtained.

[0064] S4: Compounding and vulcanization of methyl vinyl phenyl silicone rubber includes:

[0065] S4.1: 60 parts by weight of methyl vinyl phenyl silicone rubber are put into a kneader, 25 parts by weight of fumed silica, 8 parts by weight of silicone oil stabilizer and 0.03 parts by weight of 1-butynyl cyclohexanol are added, and the mixture is mixed evenly to obtain a mixed material;

[0066] S4.2: Add SiC-azodicarbonamide multilayer composite filler and 0.2 parts by weight of platinum catalyst to the mixture, heat to 120°C after mixing for 20 minutes, adjust the vacuum degree to 0.1Mpa for kneading and discharging to obtain rubber, place the rubber in an open mill for 1 hour, let it stand for 5 hours, add dipentadienyl vulcanizer for roller coating, thin pass 4 times, place in a flat vulcanizer, adjust the temperature to 160°C, the pressure to 10Mpa, and vulcanize for 2 hours to obtain a silicone rubber composite material, wherein azodicarbonamide has the characteristics of self-extinguishing and non-combustible, good stability, and can decompose when the silicone rubber-based composite insulator reaches a certain temperature to produce a large amount of gas, thereby extinguishing arc and flame retardant, ensuring the silicone rubber composite material's resistance to leakage tracking, and because azodicarbonamide is interspersed between SiC, it will not destroy the internal structure of the silicone rubber composite material after decomposition, thereby ensuring that its mechanical properties and thermal conductivity will not decrease, making the material more durable;

[0067] S4.3: The hardware and epoxy glass fiber core rod are crimped, dried and preheated, and then coated with a coupling agent. The silicone rubber composite material is then molded, subjected to secondary vulcanization and quality inspection to obtain a silicone rubber-based composite insulator. Example 3

[0068] A method for preparing a silicone rubber-based composite insulator for high voltage power transmission, such as Figure 1 As shown, the following steps are included:

[0069] S1: The preparation of SiC-azodicarbonamide multilayer composite filler includes:

[0070] S1.1: 2 parts by weight of dopamine and 4 parts by weight of azodicarbonamide were placed in a planetary ball mill, the ball milling speed was adjusted to 500 rpm, and the ball milling was performed for 6 hours to obtain a mixture with a particle size of 100 nm. The mixture was placed in a container, 15 parts by weight of deionized water were added, and the mixture was stirred for 15 minutes to obtain a mixed solution;

[0071] S1.2: Add sodium hydroxide solution to the mixed solution, adjust the pH to 9, let it stand for 5 minutes, add 8 parts by weight of SiC powder with a particle size of 1 μm, place the container in a vibrator, adjust the oscillation frequency to 120 times / minute, oscillate for 35 minutes, filter to obtain solid material I, rinse the solid material with deionized water 3 times, and then place it in an oven for drying at a temperature of 90°C to obtain a preliminary composite filler;

[0072] S1.3: 18 parts by weight of deionized water are placed in a container, tris(hydroxymethyl)aminomethane is added until the pH value of the solution is 8.7 to obtain an alkaline buffer solution, 4 parts by weight of SiC powder with a particle size of 100 nm and 0.8 parts by weight of sodium alginate are added to the alkaline buffer solution, the mixture is stirred for 20 minutes and then placed in an ultrasonic disperser, ultrasonically treated at a frequency of 80 kHz for 30 minutes, and then a preliminary composite filler and 1 part by weight of dopamine are added, and ultrasonically treated at a frequency of 40 kHz for 35 minutes, the container is sealed and placed in an oven, heated at a temperature of 75°C for 45 minutes, filtered, rinsed with deionized water 5 times, and dried at a temperature of 90°C to obtain a SiC-azodicarbonamide multilayer composite filler. The obtained SiC-azodicarbonamide multilayer composite filler has many gaps and a large specific surface area, and can be better filled and composited with methyl vinyl phenyl silicone rubber, thereby improving the mechanical properties and thermal conductivity of the silicone rubber composite material as a whole.

[0073] S2: The preparation of silicone oil stabilizer includes:

[0074] S2.1: Tetraethoxysilane, polydimethylsiloxane, vinyloxytrimethylsilane and hydrogen-containing double head are added into a container in a mass ratio of 1:0.5:0.8:0.1, nitrogen is continuously introduced into the container for 15 minutes, and then toluene is added in a mass ratio of 1:5 to the mixture in the container, stirred for 15 minutes, and then heated to 80°C, stirred for 4 hours, and filtered to obtain a filtrate;

[0075] S2.2: Place the filtrate in a vacuum distiller, control the vacuum pressure to 10000Pa, the distillation temperature to 60℃, and distill for 30 minutes to obtain a silicone oil stabilizer, which is added to the compounding process of methyl vinyl phenyl silicone rubber to improve the compatibility of fumed silica and methyl vinyl phenyl silicone rubber, avoid the reaction of hydroxyl groups on the surface of fumed silica with methyl vinyl phenyl silicone rubber during the compounding process, harden the rubber, and enhance the mechanical properties of the silicone rubber composite material.

[0076] S3: Modification of SiC-azodicarbonamide multilayer composite filler includes:

[0077] S3.1: Mix KH-550 silane coupling agent and deionized water into a container, stir and let stand for 45 minutes for hydrolysis to prepare a 2% silane coupling agent aqueous solution;

[0078] S3.2: Immerse the SiC-azodicarbonamide multilayer composite filler in an aqueous solution of a silane coupling agent for 10 minutes, introduce a large number of amino groups on its surface, reduce the hydrophilicity of the SiC-azodicarbonamide multilayer composite filler, greatly improve its compatibility with methyl vinyl phenyl silicone rubber, further improve the structural stability of the silicone rubber composite material, and make it more durable. After filtering and drying, the silane-modified SiC-azodicarbonamide multilayer composite filler is obtained.

[0079] S4: Compounding and vulcanization of methyl vinyl phenyl silicone rubber includes:

[0080] S4.1: 50 parts by weight of methyl vinyl phenyl silicone rubber are put into a kneader, 20 parts by weight of fumed silica, 6 parts by weight of silicone oil stabilizer and 0.02 parts by weight of 1-butynyl cyclohexanol are added, and the mixture is mixed evenly to obtain a mixed material;

[0081] S4.2: Add SiC-azodicarbonamide multilayer composite filler and 0.1 parts by weight of platinum catalyst to the mixture, heat to 125°C after mixing for 25 minutes, adjust the vacuum degree to 0.15Mpa for kneading and discharging to obtain rubber, place the rubber in an open mill for 2 hours, let it stand for 6 hours, add dipentadienyl vulcanizer for roller wrapping, thin pass 6 times, place in a flat vulcanizer, adjust the temperature to 180°C, the pressure to 12Mpa, and vulcanize for 3 hours to obtain a silicone rubber composite material, wherein azodicarbonamide has the characteristics of self-extinguishing and non-combustible, good stability, can decompose when the silicone rubber-based composite insulator reaches a certain temperature, produce a large amount of gas, thereby extinguishing arc and flame retardant, and ensure the silicone rubber composite material's resistance to leakage tracking. In addition, since azodicarbonamide is interspersed between SiC, it will not destroy the internal structure of the silicone rubber composite material after decomposition, thereby ensuring that its mechanical properties and thermal conductivity will not decrease, making the material more durable;

[0082] S4.3: The hardware and epoxy glass fiber core rod are crimped, dried and preheated, and then coated with a coupling agent. The silicone rubber composite material is then molded, subjected to secondary vulcanization and quality inspection to obtain a silicone rubber-based composite insulator.

[0083] Comparative Example 1:

[0084] Compared with Example 1, the difference of Comparative Example 1 is that Comparative Example 1 is a silicone rubber composite material prepared by the AC-ATH system, specifically a silicone rubber composite material prepared by the optimal process in the journal "Influence of AC / ATH System on the Performance of Silicone Rubber Composite Materials for Insulators".

[0085] The silicone rubber composite materials prepared in Example 1, Example 2, and Example 3 and Comparative Example 1 were taken, and their tensile strength was tested by the method in the national standard "GB / T528-2009 Vulcanized rubber or thermoplastic rubber-Determination of tensile stress-strain properties", and the test was performed three times respectively. The obtained data were recorded and tabulated, as shown in Table 1. It can be seen that the tensile strength of the silicone rubber composite materials prepared in Example 1, Example 2 and Example 3 is better than that in Comparative Example 1, which can prove that the embodiment prepares a silicone rubber composite material with excellent mechanical properties;

[0086] ;

[0087] Then, the silicone rubber composite materials prepared in Example 1, Example 2, and Example 3 and Comparative Example 1 were taken, and after being subjected to high temperature treatment at 200°C for 20 minutes, the tensile strength was tested using the method in the national standard "GB / T528-2009 Vulcanized rubber or thermoplastic rubber-Determination of tensile stress-strain properties", and the test was performed three times respectively. The obtained data were recorded and tabulated, as shown in Table 2. Compared with Table 1, it can be seen that the tensile strength of the silicone rubber composite materials prepared in Example 1, Example 2 and Example 3 did not change much, while the tensile strength of Comparative Example 1 was greatly reduced, which can prove that the silicone rubber composite materials prepared in the examples have good durability;

[0088] .

[0089] Comparative Example 2:

[0090] Compared with Example 1, the difference of Comparative Example 2 is that step 1 is removed in Comparative Example 2, and the remaining steps are the same as those of Example 1.

[0091] The tracking resistance of Example 1 and Comparative Example 2 was tested by the inclined plate method. The high voltage tracking tester (AST-LDQ-06, Shanghai Etisen Instrument Co., Ltd.) was used based on the national standard "GB / T6553-2014 Test Method for Evaluating Tracking Resistance and Corrosion Resistance of Electrical Insulating Materials Used under Severe Environmental Conditions" using a constant tracking voltage method. The test voltage was 4.5 kV. The test was repeated 3 times. The time when the holes or fires occurred in Example 1 and Comparative Example 2 was recorded and tabulated, as shown in Table 3. It can be seen that the hole time of Example 1 is much longer than that of Comparative Example 2, which proves that azodicarbonamide can ensure the tracking resistance of the silicone rubber composite material.

[0092] .

[0093] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A method for preparing a silicone rubber-based composite insulator for high voltage power transmission, characterized in that: The following steps are involved: S1: Preparation of SiC-azodicarbonamide multilayer composite fillers; S2: Preparation of silicone oil stabilizer; S3: Modification of SiC-azodicarbonamide multilayer composite fillers; S4: Compounding and vulcanization of methyl vinyl phenyl silicone rubber; Step S1 specifically includes the following steps: S1.1: Place 2-3 parts by weight of dopamine and 4-5 parts by weight of azodicarbonamide in a planetary ball mill, adjust the ball mill speed to 450-500 rpm, and ball mill for 4-6 hours to obtain a mixed material, place the mixed material in a container, add 15-20 parts by weight of deionized water, and stir for 10-15 minutes to obtain a mixed solution; S1.2: Add sodium hydroxide solution to the mixed solution, adjust the pH to 8-9, let it stand for 4-5 minutes, then add 8-10 parts by weight of SiC powder, place the container in a vibrator, adjust the oscillation frequency to 100-120 times / minute, oscillate for 30-35 minutes, filter to obtain solid material I, rinse the solid material with deionized water 2-3 times, and then place it in an oven to dry at 85-90°C to obtain a preliminary composite filler; S1.3: 18-20 parts by weight of deionized water are placed in a container, tris(hydroxymethyl)aminomethane is added until the pH value of the solution is 8.5-8.7 to obtain an alkaline buffer solution, 4-5 parts by weight of SiC powder and 0.8-1 parts by weight of sodium alginate are added to the alkaline buffer solution, stirred for 15-20 minutes, placed in an ultrasonic disperser, and subjected to ultrasonic treatment at a frequency of 60-80KHz for 25-30 minutes, then a preliminary composite filler and 1-2 parts by weight of dopamine are added, and then subjected to ultrasonic treatment at a frequency of 35-40KHz for 30-35 minutes, the container is sealed and placed in an oven, heated at a temperature of 70-75°C for 40-45 minutes, filtered, rinsed with deionized water 4-5 times, and dried at a temperature of 85-90°C to obtain a SiC-azodicarbonamide multilayer composite filler; Step S2 specifically includes the following steps: S2.1: Tetraethoxysilane, polydimethylsiloxane, vinyloxytrimethylsilane and hydrogen-containing double head are added into a container in a mass ratio of 1: (0.5-0.6): (0.8-1): (0.1-0.2), nitrogen is continuously introduced into the container for 10-15 minutes, and then toluene is added in a mass ratio of 1: (4-5) to the mixture in the container, stirred for 15-20 minutes, and then heated to 80-90 ° C, continued to stir for 3-4 hours, and filtered to obtain a filtrate; S2.2: placing the filtrate in a vacuum distiller, controlling the vacuum pressure to 8000-10000 Pa, the distillation temperature to 55-60° C., and distilling for 25-30 minutes to obtain a silicone oil stabilizer; Step S3 specifically includes the following steps: S3.1: Add the silane coupling agent and deionized water to a container, stir and let stand for 40-45 minutes for hydrolysis to prepare a silane coupling agent aqueous solution with a concentration of 1-2%; S3.2: immersing the SiC-azodicarbonamide multilayer composite filler in a silane coupling agent aqueous solution for 8-10 minutes, filtering and drying to obtain a silane-modified SiC-azodicarbonamide multilayer composite filler; Step S4 specifically includes the following steps: S4.1: 50-60 parts by weight of methyl vinyl phenyl silicone rubber are put into a kneader, 20-25 parts by weight of fumed silica, 6-8 parts by weight of silicone oil stabilizer and 0.02-0.03 parts by weight of 1-butynyl cyclohexanol are added, and the mixture is mixed evenly to obtain a mixed material; S4.2: Add SiC-azodicarbonamide multilayer composite filler and 0.1-0.2 parts by weight of catalyst to the mixture, mix for 20-25 minutes, heat to 120-125°C, adjust the vacuum degree to 0.1-0.15Mpa for kneading and discharging to obtain a rubber material, place the rubber material in an open mill for open mixing for 1-2 hours, let it stand for 5-6 hours, add a vulcanizing agent for roller wrapping, pass it through 4-6 times, place it in a flat vulcanizer, adjust the temperature to 160-180°C, the pressure to 10-12Mpa, and vulcanize it for 2-3 hours to obtain a silicone rubber composite material; S4.3: The hardware and epoxy glass fiber core rod are crimped, dried and preheated, and then coated with a coupling agent. The silicone rubber composite material is then molded, subjected to secondary vulcanization and quality inspection to obtain a silicone rubber-based composite insulator.

2. The method for preparing a silicone rubber-based composite insulator for high voltage power transmission according to claim 1, characterized in that: The particle size of the mixed material in step S1.1 is 50-100 nm.

3. The method for preparing a silicone rubber-based composite insulator for high voltage power transmission according to claim 1, characterized in that: The particle sizes of SiC powder in step S1.2 and step S1.3 are 0.5-1 μm and 50-100 nm, respectively.

4. The method for preparing a silicone rubber-based composite insulator for high voltage power transmission according to claim 1, characterized in that: The model of the silane coupling agent in step S3.2 is KH-550.

5. The method for preparing a silicone rubber-based composite insulator for high voltage power transmission according to claim 1, characterized in that: The catalyst in step S4.2 is platinum.

6. A silicone rubber-based composite insulator for high voltage power transmission, characterized in that: The insulator is prepared by the method for preparing a silicone rubber-based composite insulator for high-voltage power transmission according to any one of claims 1 to 5.

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