Insulating silicone rubber composite material for composite insulator and preparation method thereof

Abstract

The present disclosure relates to the technical field of composite insulator materials, and particularly relates to an insulating silicone rubber composite material for composite insulators and a preparation method thereof. The raw materials of the insulating silicone rubber composite material for composite insulators include, in terms of weight fractions, 100-120 parts of raw silicone rubber, 25-30 parts of plasma-modified white carbon black, 90-110 parts of aluminum hydroxide, 2-5 parts of hydroxyl silicone oil, 0.2-0.3 parts of vulcanizing agent, 0.5-1 part of coupling agent, 2-3 parts of iron oxide, 3-5 parts of zinc oxide, 3-5 parts of aluminum oxide, and 0.1-3 parts of methyl silicone oil. The insulating silicone rubber composite material for composite insulators prepared by the present disclosure has significant improvements in mechanical properties (tensile strength, tear strength), electrical insulation properties (breakdown voltage, tracking resistance grade), heat aging resistance, and hydrophobicity, and does not need to use organic solvents, has no waste liquid discharge, and meets the green environmental protection requirements.

Description

Technical Field

[0001] This disclosure relates to the field of composite insulator materials technology, and in particular to an insulating silicone rubber composite material for composite insulators and its preparation method. Background Technology

[0002] Composite insulators possess advantages such as light weight, high mechanical strength, strong hydrophobicity and hydrophobic migration, and high resistance to pollution flashover voltage, and are widely used in transmission lines both domestically and internationally. The skirts of composite insulators are primarily made of silicone rubber, while silica (fumed silica or precipitated silica) is an indispensable reinforcing filler in silicone rubber composites, significantly improving the mechanical properties of silicone rubber.

[0003] However, the application of silica in silicone rubber in existing technologies still faces the following technical problems: poor compatibility between silica and the silicone rubber matrix. During the mixing process, silica nanoparticles are prone to agglomeration through hydrogen bonding, forming secondary aggregates, resulting in uneven dispersion in the silicone rubber. This agglomeration not only weakens the reinforcing effect but also creates stress concentration points and electrical defects in the composite material, affecting the mechanical and electrical insulation properties of the silicone rubber.

[0004] Currently, the surface modification of silica mainly adopts wet chemical modification methods such as silane coupling agents. This method usually includes the following steps: dispersing silica in an ethanol / water mixed solvent, adding a coupling agent, heating the reaction for several hours, and then filtering, washing, and drying. This traditional method has the following shortcomings: (1) it requires the use of a large amount of organic solvent, resulting in high waste liquid treatment costs and serious environmental pollution; (2) the reaction conditions are not easy to control, and the coupling agent is prone to self-polymerization, leading to unstable modification effects; (3) nanoparticles are prone to re-aggregate during the drying process, affecting the dispersion effect.

[0005] Composite insulators are exposed to outdoor environments for extended periods, facing the combined effects of multiple aging factors, including high temperatures, ultraviolet radiation, pollution, humidity, and electric fields. Existing silicone rubber materials for composite insulators exhibit the following performance shortcomings during long-term operation: insufficient heat aging resistance; at high temperatures, silicone rubber is prone to oxidation, cross-linking, or chain breakage, leading to hardening and brittleness; arc resistance needs improvement; under polluted and humid conditions, localized arc discharge easily corrodes the silicone rubber surface; and the dispersion of multiple fillers is difficult, as silica and various powders such as iron oxide, zinc oxide, and aluminum oxide tend to agglomerate within the same matrix, resulting in deterioration of overall performance.

[0006] In summary, developing a high-performance composite insulator silicone rubber material based on plasma-modified silica and synergistic with multiple functional fillers, while establishing a matching optimized mixing process, has significant technical value and market prospects. Summary of the Invention

[0007] To address the aforementioned technical problems, this disclosure provides an insulating silicone rubber composite material for composite insulators and its preparation method, thereby resolving the technical issues of poor dispersion of silica in silicone rubber, significant environmental pollution from traditional modification methods, and insufficient overall performance of silicone rubber in composite insulators in the prior art.

[0008] In a first aspect, this disclosure provides an insulating silicone rubber composite material for composite insulators, the raw materials of which, by weight, include: 100-120 parts of raw silicone rubber, 25-30 parts of plasma-modified silica, 90-110 parts of aluminum hydroxide, 2-5 parts of hydroxyl silicone oil, 0.2-0.3 parts of vulcanizing agent, 0.5-1 part of coupling agent, 2-3 parts of iron oxide, 3-5 parts of zinc oxide, 3-5 parts of aluminum oxide, and 0.1-3 parts of methyl silicone oil.

[0009] The preparation method of plasma-modified silica includes the following steps: placing silica in a low-temperature plasma treatment device and performing plasma modification treatment for 10 min to 40 min (e.g., 10 Pa, 20 Pa, 30 Pa, 40 Pa, 50 Pa) under the conditions of a background vacuum of 10 Pa-50 Pa (e.g., 10 Pa, 20 Pa, 30 Pa, 40 Pa, 50 Pa), a working pressure of 20 Pa-100 Pa (e.g., 20 Pa, 40 Pa, 60 Pa, 80 Pa, 100 Pa), and a discharge power of 50 W-200 W (e.g., 50 W, 100 W, 150 W, 200 W) (e.g., 10 min, 15 min, 20 min, 25 min, 30 min, 35 min, 40 min).

[0010] Low-temperature plasma technology is a dry, solvent-free, and green surface treatment technology. However, there are currently no reports on the application of silica treated with this technology specifically to composite insulator silicone rubber, nor on the systematic study of its synergistic dispersion mechanism with multifunctional filler systems such as iron oxide, zinc oxide, and alumina under plasma modification conditions, as well as its comprehensive impact on electrical insulation performance, heat aging resistance, and hydrophobic properties. Therefore, this disclosure proposes a composite silicone rubber insulating material for composite insulators based on research, which can overcome at least one of the shortcomings of the aforementioned background technology. The composite silicone rubber insulating material for composite insulators prepared by plasma polymerization modification of silica using RH171 monomers has a tensile strength of 5.8 MPa, a tear strength of 29.7 kN / m, an elongation at break of 257%, a water contact angle of 120°, a thermal conductivity of 0.92 W / (m·K), and a tensile strength retention rate of more than 80% after heat aging at 200 ℃ for 72 h.

[0011] In some embodiments, the processing gas for the plasma modification treatment is one or more of argon, nitrogen, and oxygen. Argon or nitrogen is preferred.

[0012] In some embodiments, the silica is phase-processed silica or precipitated silica, with a specific surface area of ​​200 m². 2 / g-225 m 2 / g.

[0013] In other embodiments, instead of using plasma pretreatment of silica, plasma polymerization is employed to modify silica. Specifically, the plasma modification treatment is performed under conditions of a mixed gas of silane monomer gas and carrier gas. The monomers undergo a polymerization reaction on the silica surface under plasma excitation, forming a polymer coating layer, thus obtaining plasma-modified silica.

[0014] The silane monomer in the silane monomer gas is one or more of RH171 (vinyltrimethoxysilane), RH151 (vinyltriethoxysilane), and KH550 (γ-aminopropyltriethoxysilane). The carrier gas is argon or nitrogen. The volume ratio of the silane monomer gas to the carrier gas is 1:(15-20), for example, 1:15, 1:16, 1:17, 1:18, 1:19, or 1:20.

[0015] In some embodiments, the raw silicone rubber is methyl vinyl silicone rubber with a number average molecular weight of 4.5 × 10⁻⁶. 5 -8.5×10 5 The vinyl content is 0.07 wt%-0.12 wt%.

[0016] In some embodiments, the vulcanizing agent comprises one or both of 1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane and 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane. The coupling agent is a silane coupling agent, such as KH-550. The iron oxide is ferric oxide; and / or, the aluminum hydroxide is activated aluminum hydroxide powder with an average particle size of 1 μm-5 μm.

[0017] Secondly, this disclosure provides a method for preparing the insulating silicone rubber composite material for composite insulators as described in the first aspect, comprising the following steps: Step 1, Internal mixing: The raw silicone rubber and the plasma-modified silica are internally mixed to obtain the first compound. Then, the remaining raw materials except the vulcanizing agent are added in batches and internally mixed to obtain the second compound. Step 2, Kneading: The rubber compound is kneaded in a kneader and vacuumed at 140 ℃-145 ℃ for 30 min-40 min (e.g., 30 min, 32 min, 34 min, 36 min, 38 min, 40 min), and then left to stand for 20 h-30 h (e.g., 20 h, 22 h, 24 h, 26 h, 28 h, 30 h) to obtain rubber; Step 3, thin pass: Place the rubber on a two-roll mill, add vulcanizing agent, and stir to disperse it evenly to obtain vulcanized rubber; Step 4, High-temperature vulcanization: The vulcanized rubber is subjected to hot-press vulcanization treatment to obtain the insulating silicone rubber composite material for composite insulators.

[0018] In some preferred embodiments, in step 1, the raw silicone rubber and the plasma-modified silica are first kneaded for 5 min-7 min (e.g., 5 min, 6 min, 7 min), then the iron oxide, zinc oxide, aluminum oxide and part of the aluminum hydroxide are added, and kneaded for 10 min-15 min (e.g., 10 min, 11 min, 12 min, 13 min, 14 min, 15 min), then the remaining aluminum hydroxide, hydroxyl silicone oil and methyl silicone oil are added, and kneaded for 10 min-15 min (e.g., 10 min, 11 min, 12 min, 13 min, 14 min, 15 min).

[0019] In some preferred embodiments, in step 3, the number of times the object is turned over is not less than 6.

[0020] In some embodiments, step 4 involves hot-press vulcanization at 150 ℃-170 ℃ (e.g., 150 ℃, 155 ℃, 160 ℃, 165 ℃, 170 ℃) and 13 MPa-20 MPa (e.g., 13 MPa, 15 MPa, 18 MPa, 20 MPa) for 10 min-15 min (e.g., 10 min, 11 min, 12 min, 13 min, 14 min, 15 min).

[0021] Thirdly, this disclosure provides a composite insulator, comprising the insulating silicone rubber composite material for composite insulators described in the first aspect.

[0022] The technical solution provided in this disclosure has the following advantages compared with the prior art: (1) Significantly improved dispersion of silica: Low-temperature plasma treatment can introduce polar groups or form a polymer coating layer on the surface of silica, increasing surface roughness. Combined with a stepwise mixing process (first plasticizing the raw rubber and silica, then adding the powder in batches), the dispersion of silica in the silicone rubber matrix is ​​effectively improved, and agglomeration is reduced.

[0023] (2) Environmentally friendly: Plasma treatment is a dry process that does not require the use of organic solvents and has no waste liquid discharge, which meets the requirements of green environmental protection.

[0024] (3) Precise process control: The temperature (140-145℃) and vacuuming time (30 minutes) are precisely controlled during the kneading stage to effectively remove low molecular weight substances and bubbles; the vulcanizing agent is evenly dispersed by strictly turning the material through the open mill (no less than 6 times).

[0025] (4) Improved overall performance: Compared with unmodified silica, the composite silicone rubber composite material for composite insulators prepared in this disclosure has significant improvements in mechanical properties (tensile strength, tear strength), electrical insulation properties (breakdown voltage, tracking resistance) and heat aging resistance.

[0026] (5) Improved hydrophobicity: The static water contact angle can reach 120° due to the synergistic effect of plasma polymerization modification and coupling agent. Detailed Implementation

[0027] To better understand the above-mentioned objectives, features, and advantages of this disclosure, the solutions disclosed herein will be further described below. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0028] Numerous specific details are set forth in the following description in order to provide a full understanding of this disclosure, but this disclosure may also be implemented in other ways different from those described herein; obviously, the embodiments in the specification are only some, and not all, of the embodiments of this disclosure.

[0029] Example 1 A composite insulating silicone rubber material for composite insulators comprises the following raw materials by weight: 110 parts of methyl vinyl silicone rubber raw rubber, 28 parts of plasma-modified silica, 100 parts of aluminum hydroxide, 3.5 parts of hydroxyl silicone oil, 0.25 parts of vulcanizing agent, 0.8 parts of coupling agent, 2.5 parts of iron oxide, 4 parts of zinc oxide, 4 parts of aluminum oxide, and 1.5 parts of methyl silicone oil.

[0030] The average molecular weight of the methyl vinyl silicone rubber raw rubber is 4.5 × 10⁻⁶. 5 -8.5×10 5The vinyl content is 0.07 wt%-0.12 wt%. The aluminum hydroxide is activated aluminum hydroxide powder with an average particle size of 1.25 μm. The iron oxide is ferric oxide. The coupling agent is KH-550. The vulcanizing agent is 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane.

[0031] The preparation method of plasma-modified silica includes the following steps: With a specific surface area of ​​200 m² 2 / g-225 m 2 / g of fumed silica was placed in a low-temperature plasma treatment device and evacuated to 30 Pa. RH171 (vinyltrimethoxysilane) was mixed with argon at a volume ratio of 1:15 and then introduced to 50 Pa. The mixture was treated at 120 W power for 25 minutes to obtain RH171 plasma-modified silica.

[0032] The preparation method of the insulating silicone rubber composite material for composite insulators in this embodiment includes the following steps: Step 1, Internal mixing: Add the raw silicone rubber and plasma-modified silica to the hopper of the internal mixer and mix for 5 minutes; then add the coupling agent, iron oxide, zinc oxide, aluminum oxide and 40 parts of aluminum hydroxide and mix for 12 minutes; then add the remaining 60 parts of aluminum hydroxide, hydroxyl silicone oil and methyl silicone oil and mix for 12 minutes; to obtain the compound. Step 2, Kneading: Pour the mixed rubber into the hopper of the kneader and knead continuously for 2 hours. When the temperature of the rubber reaches 142 ℃, vacuum for 30 minutes and then let it stand for 24 hours to obtain rubber. Step 3, Thin pass: Place the rubber on the rollers of the open mill, distribute the vulcanizing agent evenly on the rubber, and turn the rubber on the rollers to make the vulcanizing agent and coupling agent evenly dispersed in the rubber. Step 4, High-temperature vulcanization: Place the vulcanized rubber in a mold and perform hot-press vulcanization treatment on a flat vulcanizing machine at 165 ℃ and 15 MPa to obtain the insulating silicone rubber composite material for composite insulators.

[0033] Example 2 An insulating silicone rubber composite material for composite insulators differs from Example 1 in that: Replace RH171 with KH550 (γ-aminopropyltriethoxysilane). The rest is the same as in Example 1.

[0034] Example 3 An insulating silicone rubber composite material for composite insulators differs from Example 1 in that: Replace RH171 with RH151 (vinyltriethoxysilane); The rest is the same as in Example 1.

[0035] Example 4 An insulating silicone rubber composite material for composite insulators differs from Example 1 in that: The raw materials, by weight, include: 120 parts of raw silicone rubber, 30 parts of plasma-modified silica, 110 parts of aluminum hydroxide, 5 parts of hydroxyl silicone oil, 0.3 parts of vulcanizing agent, 1 part of coupling agent, 3 parts of iron oxide, 5 parts of zinc oxide, 5 parts of aluminum oxide, and 3 parts of methyl silicone oil. The rest is the same as in Example 1.

[0036] Example 5 An insulating silicone rubber composite material for composite insulators differs from Example 1 in that: The raw materials, by weight, include: 100 parts of raw silicone rubber, 25 parts of plasma-modified silica, 90 parts of aluminum hydroxide, 2 parts of hydroxyl silicone oil, 0.2 parts of vulcanizing agent, 0.5 parts of coupling agent, 2 parts of iron oxide, 3 parts of zinc oxide, 3 parts of aluminum oxide, and 0.1 parts of methyl silicone oil. The rest is the same as in Example 1.

[0037] Example 6 An insulating silicone rubber composite material for composite insulators differs from Example 1 in that: In the preparation method of plasma-modified silica, no silane monomer was introduced, and the silica was treated at 100 W power for 15 min. The rest is the same as in Example 1.

[0038] Example 7 An insulating silicone rubber composite material for composite insulators differs from Example 1 in that: The coupling agent KH-550 was replaced with KH-570; The rest is the same as in Example 1.

[0039] Comparative Example 1 An insulating silicone rubber composite material for composite insulators differs from Example 1 in that: Unmodified fumed silica was used to replace plasma-modified silica; The rest is the same as in Example 1.

[0040] Comparative Example 2 An insulating silicone rubber composite material for composite insulators differs from Example 1 in that: The plasma-modified silica was replaced with a first type of silica. The preparation method of the first type of silica includes the following steps: dispersing fumed silica in an ethanol / water mixed solvent, adding 5% RH171, reacting at 60 °C for 4 hours, filtering, washing, and drying.

[0041] The rest is the same as in Example 1.

[0042] Performance testing The performance of the silicone rubber composite materials for composite insulators prepared in Examples 1-7 and Comparative Examples 1-2 was tested according to the following standards: Tensile strength: Tested in accordance with GB / T 528-2009 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber", each sample was tested 3 times and the average value was taken.

[0043] Tear strength: Tested according to GB / T 529-2008 "Determination of tear strength of vulcanized rubber or thermoplastic rubber", each sample was tested 3 times and the average value was taken.

[0044] Elongation at break: Tested in accordance with GB / T 528-2009 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber", and measured simultaneously with tensile strength.

[0045] Water contact angle: The test was conducted in accordance with GB / T 30693-2014 "Measurement of water contact angle of plastic film". A static contact angle measuring instrument was used, and the test temperature was room temperature. Three different positions were tested for each sample, and the average value was taken.

[0046] Thermal conductivity: Tested according to GB / T 10297-2015 "Determination of thermal conductivity of non-metallic solid materials by hot wire method" at room temperature.

[0047] Thermal aging performance: Tested according to GB / T 3512-2014 "Accelerated aging and heat resistance test of vulcanized rubber or thermoplastic rubber in hot air", with aging conditions of 200 ℃×72 h.

[0048] The results are shown in Table 1.

[0049] Table 1. Performance test results of silicone rubber composite materials for composite insulators

[0050] The data from Comparative Example 1 show that when unmodified silica is directly filled into silicone rubber, the tensile strength, tear strength, thermal conductivity, and heat aging retention rate of the resulting silicone rubber composite for composite insulators are significantly lower than those of the examples due to severe hydroxyl aggregation on the silica surface and poor compatibility with the matrix. This indicates that surface modification of silica is a necessary prerequisite for improving the overall performance of silicone rubber composites for composite insulators.

[0051] The data from Comparative Example 2 show that the tensile strength, tear strength, and thermal conductivity of the silicone rubber composite material for composite insulators prepared by traditional wet-process modified silica are significantly lower than those prepared by plasma polymerization of silica in this disclosure. This indicates that the plasma dry modification process is superior to the wet modification process and avoids the use of organic solvents.

[0052] Data from Example 6 shows that the overall performance of the silicone rubber composite material for composite insulators prepared by pretreating silica with argon plasma without introducing silane monomers for polymerization modification is lower than that of Example 1, indicating that the construction of a polymer coating layer on the surface of silica is the key to improving material performance.

[0053] Data from Example 7 shows that when KH-570 coupling agent was used instead of KH-550 in the formulation, the tensile strength, tear strength, and water contact angle of the resulting silicone rubber composite material for composite insulators were all lower than those in Example 1, indicating that the synergistic effect of KH-550 coupling agent was better than that of KH-570.

[0054] This disclosure uses RH171 plasma-modified silica, combined with KH-550 coupling agent and a stepwise mixing process, to prepare a silicone rubber composite material for composite insulators. The resulting material significantly outperforms the comparative examples in terms of mechanical properties, hydrophobic properties, thermal conductivity, and heat aging resistance, thus verifying the advanced nature and effectiveness of the technical solution disclosed herein.

[0055] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0056] The above description is merely a specific embodiment of this disclosure, enabling those skilled in the art to understand or implement it. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not to be limited to the embodiments described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An insulating silicone rubber composite material for composite insulators, characterized in that, The raw materials, by weight, include: 100-120 parts of raw silicone rubber, 25-30 parts of plasma-modified silica, 90-110 parts of aluminum hydroxide, 2-5 parts of hydroxyl silicone oil, 0.2-0.3 parts of vulcanizing agent, 0.5-1 part of coupling agent, 2-3 parts of iron oxide, 3-5 parts of zinc oxide, 3-5 parts of aluminum oxide, and 0.1-3 parts of methyl silicone oil.

2. The insulating silicone rubber composite material for composite insulators according to claim 1, characterized in that, The preparation method of plasma-modified silica includes the following steps: placing silica in a low-temperature plasma treatment device and performing plasma modification treatment for 10 min to 40 min under the conditions of background vacuum of 10 Pa-50 Pa, working pressure of 20 Pa-100 Pa, and discharge power of 50 W-200 W.

3. The insulating silicone rubber composite material for composite insulators according to claim 2, characterized in that, The processing gas for the plasma modification treatment is one or more of argon, nitrogen, and oxygen.

4. The insulating silicone rubber composite material for composite insulators according to claim 2, characterized in that, The plasma modification treatment is carried out under the condition of introducing a mixture of silane monomer gas and carrier gas.

5. The insulating silicone rubber composite material for composite insulators according to claim 4, characterized in that, The silane monomer in the silane monomer gas is one or more of RH171 (vinyltrimethoxysilane), RH151 (vinyltriethoxysilane), and KH550 (γ-aminopropyltriethoxysilane); and / or, the carrier gas is argon or nitrogen; and / or, the volume ratio of the silane monomer gas to the carrier gas is 1:(15-20).

6. The insulating silicone rubber composite material for composite insulators according to any one of claims 1 to 5, characterized in that, The raw silicone rubber is methyl vinyl silicone rubber with a number average molecular weight of 4.5 × 10⁻⁶. 5 -8.5×10 5 The vinyl content is 0.07 wt%-0.12 wt%.

7. The insulating silicone rubber composite material for composite insulators according to any one of claims 1 to 5, characterized in that, The vulcanizing agent includes one or two of 1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane and 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane; and / or, the coupling agent is silane coupling agent KH550; and / or, the iron oxide is ferric oxide; and / or, the aluminum hydroxide is active aluminum hydroxide powder with an average particle size of 1 μm-5 μm.

8. A method for preparing an insulating silicone rubber composite material for composite insulators according to any one of claims 1 to 7, characterized in that, Includes the following steps: Step 1, Internal mixing: The raw silicone rubber and the plasma-modified silica are subjected to internal mixing for the first time to obtain the first compound. Then, the remaining raw materials except the vulcanizing agent are added in batches and internally mixed to obtain the second compound. Step 2, Kneading: Knead the rubber compound in a kneader and vacuum it at 140 ℃-145 ℃ for 30 min-40 min, then let it stand for 20 h-30 h to obtain rubber. Step 3, thin pass: Place the rubber on a two-roll mill, add vulcanizing agent, and stir to disperse it evenly to obtain vulcanized rubber; Step 4, High-temperature vulcanization: The vulcanized rubber is subjected to hot-press vulcanization treatment to obtain the insulating silicone rubber composite material for composite insulators.

9. The preparation method according to claim 8, characterized in that, In step 1, the raw silicone rubber and the plasma-modified silica are first mixed in an intensive kneading process for 5-7 minutes, then the iron oxide, zinc oxide, aluminum oxide, and part of the aluminum hydroxide are added, and the mixture is mixed in an intensive kneading process for 10-15 minutes. Then the remaining aluminum hydroxide, hydroxyl silicone oil, and methyl silicone oil are added, and the mixture is mixed in an intensive kneading process for 10-15 minutes. And / or, in step 3, the mixture is turned over at least 6 times. And / or, in step 4, the mixture is hot-pressed and vulcanized at 150 ℃-170 ℃ and 13 MPa-20 MPa for 10-15 minutes.

10. A composite insulator, characterized in that, Including the insulating silicone rubber composite material for composite insulators as described in any one of claims 1 to 7.

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