Composite insulator and preparation method thereof

Abstract

The present invention relates to the field of insulator technology, and in particular to a composite insulator and a preparation method thereof. The composite insulator of the present invention comprises an insulator body and a vulcanized silicone rubber coating the insulator body; the vulcanized silicone rubber comprises the following components in parts by weight: 60-70 parts of methyl vinyl silicone rubber, 10-20 parts of ethylene propylene diene monomer rubber, 5-10 parts of modified glass fiber, 20-30 parts of filler, 0.3-0.5 parts of dimethyl silicone oil, 1-5 parts of a compatibilizer, 3-5 parts of stearic acid, and 1-3 parts of a vulcanizing agent; the preparation process of the modified glass fiber is as follows: polyimide, a silane coupling agent, and humic acid are added to anhydrous ethanol, mixed evenly, and then glass fiber is added. After heating and reacting, the modified glass fiber is calcined to obtain the modified glass fiber. The composite insulator obtained by the present invention has good mechanical properties, corona resistance, and anti-pollution flashover performance.

Description

Technical Field

[0001] The present invention relates to the technical field of insulators, and in particular to a composite insulator and a preparation method thereof. Background Art

[0002] Insulators are electrical components used to isolate and support conductors, primarily in transmission lines and substations. They are a key component in insulating power equipment and transmission lines. Their primary function is to isolate the conductors or equipment from the supporting structure or ground, preventing current leakage and arcing. Insulators are categorized as porcelain insulators and composite insulators.

[0003] High-voltage transmission line insulators are crucial components for maintaining the normal operation of transmission lines. Insulators are susceptible to aging in outdoor environments. For example, existing vulcanized silicone rubber substrates generally lack sufficient thermal conductivity, making it difficult to effectively dissipate the transient high heat energy generated by discharges, resulting in poor corona resistance. Existing technologies often employ the addition of inorganic fillers (such as SiO2) or surface coatings with silicone oil or fluorine. This can lead to poor mechanical properties and potential environmental accumulation risks. Furthermore, in outdoor service, composite insulators are susceptible to the deposition of pollutants from natural sources, inevitably causing partial discharge on or within the surface of composite insulators. This can lead to contamination flashover, causing insulator aging and damage, seriously threatening the safe operation of transmission lines, creating significant safety hazards and causing significant economic losses. Currently, preventing insulator contamination flashover relies primarily on manual cleaning using high-pressure water guns to remove contaminants from the insulator surface. This method is inefficient, risky, and expensive.

[0004] Therefore, in order to solve the above technical problems, it is urgent to develop a composite insulator with good mechanical properties, corona resistance and anti-pollution flashover performance. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, the primary purpose of the present invention is to provide a composite insulator. The present invention introduces modified glass fiber and a new type of filler to form a vulcanized silicone rubber with excellent mechanical properties, corona resistance, and pollution flashover resistance on the surface of the insulator.

[0006] Another object of the present invention is to provide a method for preparing a composite insulator, which is simple and efficient, is beneficial to industrial production, and improves production efficiency.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] The present invention provides a composite insulator, comprising an insulator body and vulcanized silicone rubber covering the insulator body;

[0009] The vulcanized silicone rubber comprises the following components in parts by weight: 60-70 parts of methyl vinyl silicone rubber, 10-20 parts of EPDM rubber, 5-10 parts of modified glass fiber, 20-30 parts of filler, 0.3-0.5 parts of dimethyl silicone oil, 1-5 parts of compatibilizer, 3-5 parts of stearic acid, and 1-3 parts of vulcanizing agent;

[0010] The preparation process of the modified glass fiber is as follows:

[0011] Polyimide, silane coupling agent and humic acid are added to anhydrous ethanol, mixed evenly, and then glass fiber is added. After heating for reaction, the mixture is calcined to obtain modified glass fiber.

[0012] Furthermore, the mass ratio of the polyimide, silane coupling agent, humic acid, glass fiber, and anhydrous ethanol is 1: (1-2): (15-20): (5-9): 100; the silane coupling agent is any one of KH550, KH560, and γ-methacryloxypropyltrimethoxysilane; and the glass fiber has a diameter of 9-13 μm and a length of 1-6 mm.

[0013] Furthermore, the temperature of the heating reaction is 80-90° C., and the time is 3-5 hours; the temperature of the calcination is 450-500° C., and the time is 30-60 minutes.

[0014] Furthermore, the preparation process of the filler is as follows:

[0015] (1) adding potassium titanate whiskers to a mixed solution of ethanol and water, then adding vinyltrimethoxysilane, reacting at room temperature, filtering, and drying to obtain potassium titanate whiskers pretreated with a silane coupling agent;

[0016] (2) Potassium titanate whiskers pretreated with a silane coupling agent are added to dimethylformamide, and then trifluoroethyl methacrylate and azobisisobutyronitrile are added, heated for reaction, and the filler is obtained after filtering, washing, and drying.

[0017] Furthermore, in step (1), the mass ratio of the potassium titanate whiskers, vinyltrimethoxysilane, and the mixed solution is 1: (0.08-0.12): 10; the mass ratio of the ethanol to water is (7-9): 1; the reaction time at room temperature is 30-90 min; and the diameter of the potassium titanate whiskers is 3-5 µm and the length is 10-30 µm.

[0018] Furthermore, in step (2), the mass ratio of the potassium titanate whiskers pretreated with the silane coupling agent, trifluoroethyl methacrylate, and azobisisobutyronitrile is 100:(20-40):(0.5-1.2), and the amount ratio of the potassium titanate whiskers pretreated with the silane coupling agent and dimethylformamide is 1 g:10 mL.

[0019] Furthermore, in step (2), the heating reaction temperature is 50-60°C and the time is 3-5h.

[0020] Furthermore, the insulator body is a porcelain insulator or a glass insulator; the compatibilizer is ethylene vinyl acetate, and the vulcanizing agent is dicumyl peroxide.

[0021] The present invention provides a method for preparing the composite insulator, comprising the following steps:

[0022] a. Weigh methyl vinyl silicone rubber, EPDM rubber, modified glass fiber, filler, dimethyl silicone oil, compatibilizer, stearic acid, and vulcanizing agent in parts by weight, mix the methyl vinyl silicone rubber, EPDM rubber, modified glass fiber, filler, dimethyl silicone oil, compatibilizer, and stearic acid, and then cool to room temperature and vulcanize by adding a vulcanizing agent to obtain a vulcanized silicone rubber;

[0023] b. Coat the surface of the insulator with a silane coupling agent solution, then mold it with vulcanized silicone rubber and perform secondary vulcanization to obtain a composite insulator.

[0024] Furthermore, the temperature of the banburying is 50-60° C., and the stirring time is 9-11 hours; the temperature of the vulcanization is 100-120° C., and the time is 1.5-2.5 hours; and the pressure during vulcanization is 10-20 MPa.

[0025] Furthermore, the temperature of the secondary vulcanization is 100-120° C., the time is 1.5-2.5 hours, and the pressure during the secondary vulcanization is 10-20 MPa.

[0026] The present invention has the following effects compared to the prior art:

[0027] 1. The present invention provides a composite insulator. By introducing modified glass fiber and a new filler, a vulcanized silicone rubber with excellent corona resistance and anti-pollution flashover performance is formed on the surface of the insulator, while also ensuring the good mechanical properties of the vulcanized silicone rubber. Specifically, humic acid, polyimide, and silane coupling agent are introduced into the modified glass fiber. After calcination, the humic acid forms a porous carbon layer on the surface of the glass fiber. The addition of the silane coupling agent and polyimide further hybridizes the porous carbon layer. The silica reinforcement layer formed by calcination and the polyimide form a cross-linked network structure with good thermal conductivity, improving the composite insulator's dispersibility of energy generated by partial discharge and improving the corona resistance of the vulcanized silicone rubber. The surface roughness of the modified glass fiber is increased, improving the bonding strength with other components and improving the mechanical properties of the insulator. The filler of the present invention is modified by grafting potassium titanate whiskers to introduce hydrophobic fluorine atoms on their surface, so that the vulcanized silicone rubber has good anti-pollution ability and improves the anti-pollution flashover performance of the composite insulator.

[0028] 2. The present invention provides a method for preparing a composite insulator, which is simple and efficient, is beneficial to industrial production, and improves production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is an electron microscope image of the modified glass fiber obtained in Example 1 of the present invention;

[0030] Figure 2 This is an electron microscope image of the filler obtained in Example 1 of the present invention. DETAILED DESCRIPTION

[0031] The present invention will be described in further detail below in conjunction with the examples, but embodiments of the present invention are not limited thereto. Unless otherwise stated, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art. The test methods for which specific experimental conditions are not specified in the following examples are usually based on conventional experimental conditions or the experimental conditions recommended by the manufacturer. Unless otherwise stated, the reagents and raw materials used in the present invention can be obtained commercially.

[0032] In the embodiment of the present invention, the diameter of the glass fiber is 9-13 μm and the length is 1-6 mm. The diameter of the potassium titanate whisker is 3-5 μm and the length is 10-30 μm.

[0033] Example 1

[0034] A composite insulator, comprising an insulator body and a vulcanized silicone rubber covering the insulator body; the vulcanized silicone rubber comprises the following components, measured in parts by weight: 65 parts of methyl vinyl silicone rubber, 15 parts of EPDM rubber, 8 parts of modified glass fiber, 25 parts of filler, 0.4 parts of dimethyl silicone oil, 3 parts of ethylene vinyl acetate, 4 parts of stearic acid, and 2 parts of dicumyl peroxide;

[0035] Among them, the preparation process of modified glass fiber is as follows:

[0036] Add polyimide, KH550, and humic acid to anhydrous ethanol, mix well, and then add glass fiber. The mass ratio of polyimide, KH550, humic acid, glass fiber, and anhydrous ethanol is 1:1.5:18:7:100. After heating at 85℃ for 4 hours, calcination at 470℃ for 40 minutes under N2 atmosphere was performed to obtain modified glass fiber. The electron microscope image of the modified glass fiber is shown below. Figure 1 shown.

[0037] The preparation process of the filler is as follows:

[0038] (1) Anhydrous ethanol and water are mixed uniformly in a mass ratio of 9:1 to prepare a mixed solution of anhydrous ethanol and water, potassium titanate whiskers are added to the mixed solution of anhydrous ethanol and water, and then vinyl trimethoxysilane is added, wherein the mass ratio of potassium titanate whiskers, vinyl trimethoxysilane and the mixed solution is 1:0.1:10; the reaction is carried out at room temperature for 60 minutes, and the reaction solution is filtered and dried to obtain potassium titanate whiskers pretreated with a silane coupling agent;

[0039] (2) Add potassium titanate whiskers pretreated with silane coupling agent to dimethylformamide, with the ratio of potassium titanate whiskers pretreated with silane coupling agent to dimethylformamide being 1g:10mL; then add trifluoroethyl methacrylate and azobisisobutyronitrile, with the mass ratio of potassium titanate whiskers pretreated with silane coupling agent, trifluoroethyl methacrylate and azobisisobutyronitrile being 100:30:1; heat the reaction at 55℃ for 4h, filter, wash and dry to obtain the filler. The electron microscope image of the filler is shown in the figure below. Figure 2 shown.

[0040] The preparation method of the composite insulator comprises the following steps:

[0041] a. Weigh methyl vinyl silicone rubber, EPDM rubber, modified glass fiber, filler, dimethyl silicone oil, ethylene vinyl acetate, stearic acid, and dicumyl peroxide according to the parts by weight. Mix the methyl vinyl silicone rubber, EPDM rubber, modified glass fiber, filler, dimethyl silicone oil, ethylene vinyl acetate, and stearic acid and stir at 55 ° C for 10 h, then cool to room temperature, add dicumyl peroxide, adjust the temperature to 110 ° C and the pressure to 15 MPa, and vulcanize for 2 h to obtain vulcanized silicone rubber;

[0042] b. Add KH550 to deionized water, stir and let it stand for 60 minutes to prepare a KH550 aqueous solution with a mass concentration of 2%. Coat the surface of the glass insulator with the KH550 aqueous solution, and then mold it with vulcanized silicone rubber. Adjust the temperature to 110°C and the pressure to 15 MPa for secondary vulcanization for 2 hours to obtain a composite insulator.

[0043] Example 2

[0044] A composite insulator, comprising an insulator body and a vulcanized silicone rubber covering the insulator body; the vulcanized silicone rubber comprises the following components, measured in parts by weight: 60 parts of methyl vinyl silicone rubber, 10 parts of EPDM rubber, 5 parts of modified glass fiber, 20 parts of filler, 0.3 parts of dimethyl silicone oil, 1 part of ethylene vinyl acetate, 3 parts of stearic acid, and 1 part of dicumyl peroxide;

[0045] The preparation process of the modified glass fiber is as follows:

[0046] Polyimide, KH550, and humic acid were added to anhydrous ethanol and mixed evenly, and then glass fiber was added. The mass ratio of polyimide, KH550, humic acid, glass fiber, and anhydrous ethanol was 1:1:15:5:100. After heating at 80°C for 5 hours, the mixture was calcined at 450°C for 60 minutes under a nitrogen atmosphere to obtain modified glass fiber.

[0047] The preparation process of the filler is as follows:

[0048] (1) Anhydrous ethanol and water are mixed uniformly in a mass ratio of 9:1 to prepare a mixed solution of anhydrous ethanol and water, potassium titanate whiskers are added to the mixed solution of anhydrous ethanol and water, and then vinyl trimethoxysilane is added, wherein the mass ratio of potassium titanate whiskers, vinyl trimethoxysilane and the mixed solution is 1:0.08:10; the reaction is carried out at room temperature for 50 minutes, and the reaction solution is filtered and dried to obtain potassium titanate whiskers pretreated with a silane coupling agent;

[0049] (2) Potassium titanate whiskers pretreated with silane coupling agent were added to dimethylformamide, with the amount ratio of potassium titanate whiskers pretreated with silane coupling agent and dimethylformamide being 1 g:10 mL; trifluoroethyl methacrylate and azobisisobutyronitrile were then added, with the mass ratio of potassium titanate whiskers pretreated with silane coupling agent, trifluoroethyl methacrylate and azobisisobutyronitrile being 100:20:0.5; the mixture was heated at 50°C for 5 h, and the filler was obtained after filtration, washing and drying.

[0050] The preparation method of the composite insulator comprises the following steps:

[0051] a. Weigh methyl vinyl silicone rubber, EPDM rubber, modified glass fiber, filler, dimethyl silicone oil, ethylene - vinyl acetate, stearic acid, and dicumyl peroxide according to the weight parts, and mix the methyl vinyl silicone rubber, EPDM rubber, modified glass fiber, filler, dimethyl silicone oil, ethylene - vinyl acetate, and stearic acid at 50 ° C with stirring for 11 hours, then cool to room temperature, add dicumyl peroxide, adjust the temperature to 100 ° C and the pressure to 10 MPa, and vulcanize for 1.5 hours to obtain vulcanized silicone rubber;

[0052] b. Add KH550 to deionized water, stir, and let it stand for 60 minutes to prepare a KH550 aqueous solution with a mass concentration of 2%. Coat the surface of the glass insulator with the KH550 aqueous solution, then mold it with vulcanized silicone rubber. Adjust the temperature to 100°C and the pressure to 10 MPa for secondary vulcanization for 1.5 hours to obtain a composite insulator.

[0053] Example 3

[0054] A composite insulator, comprising an insulator body and a vulcanized silicone rubber covering the insulator body; the vulcanized silicone rubber comprises the following components, measured in parts by weight: 70 parts of methyl vinyl silicone rubber, 20 parts of EPDM rubber, 10 parts of modified glass fiber, 30 parts of filler, 0.5 parts of dimethyl silicone oil, 5 parts of ethylene vinyl acetate, 5 parts of stearic acid, and 3 parts of dicumyl peroxide;

[0055] The preparation process of the modified glass fiber is as follows:

[0056] Polyimide, KH550, and humic acid were added to anhydrous ethanol and mixed evenly, and then glass fiber was added. The mass ratio of polyimide, KH550, humic acid, glass fiber, and anhydrous ethanol was 1:2:20:9:100. After heating at 90°C for 3 hours, the modified glass fiber was calcined at 500°C for 30 minutes under a nitrogen atmosphere to obtain the modified glass fiber.

[0057] The preparation process of the filler is as follows:

[0058] (1) Anhydrous ethanol and water are mixed uniformly in a mass ratio of 9:1 to prepare a mixed solution of anhydrous ethanol and water, potassium titanate whiskers are added to the mixed solution of anhydrous ethanol and water, and then vinyl trimethoxysilane is added, wherein the mass ratio of potassium titanate whiskers, vinyl trimethoxysilane and the mixed solution is 1:0.12:10; the reaction is carried out at room temperature for 90 minutes, and the reaction solution is filtered and dried to obtain potassium titanate whiskers pretreated with a silane coupling agent;

[0059] (2) Potassium titanate whiskers pretreated with silane coupling agent were added to dimethylformamide, with the amount ratio of potassium titanate whiskers pretreated with silane coupling agent and dimethylformamide being 1 g:10 mL; trifluoroethyl methacrylate and azobisisobutyronitrile were then added, with the mass ratio of potassium titanate whiskers pretreated with silane coupling agent, trifluoroethyl methacrylate and azobisisobutyronitrile being 100:40:1.2; the mixture was heated at 60°C for 3 h, and the filler was obtained after filtration, washing and drying.

[0060] The preparation method of the composite insulator comprises the following steps:

[0061] a. Weigh methyl vinyl silicone rubber, EPDM rubber, modified glass fiber, filler, dimethyl silicone oil, ethylene - vinyl acetate, stearic acid, and dicumyl peroxide according to the weight parts, and mix the methyl vinyl silicone rubber, EPDM rubber, modified glass fiber, filler, dimethyl silicone oil, ethylene - vinyl acetate, and stearic acid at 60 ° C and stir for 11 hours, then cool to room temperature, add dicumyl peroxide, adjust the temperature to 120 ° C and the pressure to 20 MPa, and vulcanize for 2.5 hours to obtain vulcanized silicone rubber;

[0062] b. Add KH550 to deionized water, stir and let it stand for 60 minutes to prepare a KH550 aqueous solution with a mass concentration of 2%. Coat the surface of the glass insulator with the KH550 aqueous solution, and then mold it with vulcanized silicone rubber. Adjust the temperature to 120°C and the pressure to 20 MPa for secondary vulcanization for 2.5 hours to obtain a composite insulator.

[0063] Comparative Example 1

[0064] Comparative Example 1 is basically the same as Example 1, except that the modified glass fiber is replaced by glass fiber, and the rest is consistent with Example 1.

[0065] Comparative Example 2

[0066] Comparative Example 2 is basically the same as Example 1, except that the addition of humic acid is omitted during the preparation of the modified glass fiber, and the rest is consistent with Example 1.

[0067] Comparative Example 3

[0068] Comparative Example 3 is basically the same as Example 1, except that the filler is replaced by potassium titanate whiskers pretreated with silane coupling agent obtained in step (1) of Example 1, and the rest are the same as Example 1.

[0069] Test Case

[0070] (1) According to the test standard of GB / T22689-2008, the corona resistance performance of the vulcanized silicone rubber coated insulator bodies obtained in Examples 1-3 and Comparative Examples 1-3 was tested at pulse amplitudes of 2 kV and 3 kV. The test results are shown in Table 1.

[0071] (2) The tear strength and tensile strength of the vulcanized silicone rubber covering the insulator body were tested according to the standard GB / T528-2009. The test results are shown in Table 2.

[0072] (3) The contact angles of the vulcanized silicone rubbers of Examples 1-3 and Comparative Examples 1-3 were tested. The test results are shown in Table 2.

[0073] Table 1

[0074]

[0075] As shown in Table 1, as the pulse amplitude increases, the corona resistance time of the electromagnetic insulators obtained in Examples 1-3 is longer than that of Comparative Examples 1-3, demonstrating that the composite insulators obtained in accordance with the present invention have excellent corona resistance, which helps extend the service life of the composite insulators. Comparative Examples 1 and 2, respectively, replace the modified glass fiber with glass fiber and omit the addition of humic acid during the preparation of the modified glass fiber. The corona resistance time is significantly shorter than that of Example 1. This demonstrates that the modified glass fiber of the present invention helps improve the composite insulator's ability to disperse the energy generated by partial discharge, thereby enhancing the corona resistance of the vulcanized silicone rubber.

[0076] Table 2

[0077]

[0078] As shown in Table 2, the vulcanized silicone rubber obtained in Examples 1-3 of the present invention exhibited excellent mechanical strength, all maintained between 56 and 60 MPa, and tensile strengths maintained between 17 and 20 MPa. Furthermore, the water contact angles of the vulcanized silicone rubber obtained in Examples 1-3 were all greater than 150°, indicating excellent hydrophobicity. In operating environments, water droplets sliding off the surface of the composite insulators remove dust and stains, providing excellent self-cleaning properties and improving the composite insulator's pollution flashover resistance, thereby reducing economic losses caused by pollution flashover, ice flashover, and other factors.

[0079] The above embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and replacements made by technicians in this field on the basis of the present invention fall within the scope of protection required by the present invention.

Claims

1. A composite insulator, characterized in that: comprising an insulator body and vulcanized silicone rubber covering the insulator body; The vulcanized silicone rubber comprises the following components in parts by weight: 60-70 parts of methyl vinyl silicone rubber, 10-20 parts of EPDM rubber, 5-10 parts of modified glass fiber, 20-30 parts of filler, 0.3-0.5 parts of dimethyl silicone oil, 1-5 parts of compatibilizer, 3-5 parts of stearic acid, and 1-3 parts of vulcanizing agent; The preparation process of the modified glass fiber is as follows: Adding polyimide, silane coupling agent and humic acid to anhydrous ethanol, mixing evenly, then adding glass fiber, heating and reacting, and calcining to obtain modified glass fiber; The preparation process of the filler is as follows: (1) adding potassium titanate whiskers to a mixed solution of ethanol and water, then adding vinyltrimethoxysilane, reacting at room temperature, filtering, and drying to obtain potassium titanate whiskers pretreated with a silane coupling agent; (2) Potassium titanate whiskers pretreated with a silane coupling agent are added to dimethylformamide, and then trifluoroethyl methacrylate and azobisisobutyronitrile are added, heated for reaction, and the filler is obtained after filtering, washing, and drying.

2. A composite insulator according to claim 1, characterized in that: The mass ratio of the polyimide, silane coupling agent, humic acid, glass fiber, and anhydrous ethanol is 1:(1-2):(15-20):(5-9):100; the silane coupling agent is any one of KH550, KH560, and γ-methacryloxypropyltrimethoxysilane; and the glass fiber has a diameter of 9-13 μm and a length of 1-6 mm.

3. The composite insulator according to claim 1, characterized in that: During the preparation of the modified glass fiber, the heating reaction temperature is 80-90° C. and the time is 3-5 hours; the calcination temperature is 450-500° C. and the time is 30-60 minutes.

4. The composite insulator according to claim 1, characterized in that: In step (1), the mass ratio of the potassium titanate whiskers, vinyltrimethoxysilane, and the mixed solution is 1: (0.08-0.12): 10; the mass ratio of the ethanol to water is (7-9): 1; the reaction time at room temperature is 30-90 minutes; the diameter of the potassium titanate whiskers is 3-5 μm, and the length is 10-30 μm.

5. The composite insulator according to claim 1, characterized in that: In step (2), the mass ratio of the potassium titanate whiskers pretreated with the silane coupling agent, trifluoroethyl methacrylate, and azobisisobutyronitrile is 100:(20-40):(0.5-1.2), and the amount ratio of the potassium titanate whiskers pretreated with the silane coupling agent and dimethylformamide is 1 g:10 mL.

6. The composite insulator according to claim 1, characterized in that: In step (2), the heating reaction temperature is 50-60°C and the time is 3-5 hours.

7. The composite insulator according to claim 1, characterized in that: The insulator body is a porcelain insulator or a glass insulator; the compatibilizer is ethylene vinyl acetate, and the vulcanizing agent is dicumyl peroxide.

8. The method for preparing a composite insulator according to any one of claims 1 to 7, characterized in that: The method comprises the following preparation steps: a. Weigh methyl vinyl silicone rubber, EPDM rubber, modified glass fiber, filler, dimethyl silicone oil, compatibilizer, stearic acid, and vulcanizing agent in parts by weight, mix the methyl vinyl silicone rubber, EPDM rubber, modified glass fiber, filler, dimethyl silicone oil, compatibilizer, and stearic acid, and then cool to room temperature and vulcanize by adding a vulcanizing agent to obtain a vulcanized silicone rubber; b. Coat the surface of the insulator with a silane coupling agent solution, then mold it with vulcanized silicone rubber and perform secondary vulcanization to obtain a composite insulator.

9. The method for preparing a composite insulator according to claim 8, characterized in that: The temperature of the banburying is 50-60° C., and the stirring time is 9-11 hours; the temperature of the vulcanization is 100-120° C., and the time is 1.5-2.5 hours. The pressure during vulcanization is 10-20 MPa.

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