Silicone rubber for composite insulator and preparation method thereof

Abstract

The invention provides silicone rubber for a composite insulator and a preparation method of the silicone rubber for the composite insulator. The silicone rubber composition is prepared from the following raw materials in parts by weight: 20 to 80 parts of first methyl vinyl silicone rubber raw rubber, 10 to 50 parts of second methyl vinyl silicone rubber raw rubber, 20 to 60 parts of white carbon black, 1 to 15 parts of hydroxyl silicone oil, 80 to 120 parts of aluminum hydroxide, 1 to 10 parts of P-N-Si tracking-resistant auxiliary agent, 0.1 to 2.2 parts of first silane coupling agent, 1 to 4 parts of dimethyl silicone oil and 0.01 to 1 part of release agent. The preparation raw materials of the P-N-Si tracking resistant auxiliary agent comprise a second silane coupling agent, phytic acid and melamine, the aluminum hydroxide is silane modified aluminum hydroxide, and the particle size D50 of the aluminum hydroxide is 1-5 [mu] m. Through cooperation of the P-N-Si anti-tracking auxiliary agent and the silane modified aluminum hydroxide, the filling amount of the aluminum hydroxide can be reduced while the anti-tracking performance of the composite insulator silicon rubber is improved, and the problems of processability and poor mechanical performance are effectively solved.

Description

Technical Field

[0001] The invention relates to the field of silicone rubber materials, and in particular to silicone rubber for composite insulators and a preparation method thereof. Background Art

[0002] Composite insulators are light in weight, easy to transport and install, easy to process and shape, and have good seismic resistance. They are widely used in the power field at home and abroad. They are mainly composed of three parts: silicone rubber shed sheath, glass core rod and end fittings. Among them, the shed sheath made of silicone rubber material will gradually age due to long-term exposure to corona discharge, ultraviolet radiation, high temperature and humidity, and dirt. As time goes by, the aging effect will cause the insulation performance, mechanical properties, hydrophobicity and anti-fouling performance of the composite insulator to decline, and cracking, powdering, flashover, heating and other problems will occur, which seriously threaten the safe and stable operation of the power grid.

[0003] The widely used silicone rubber shed material is mainly composed of methyl vinyl silicone rubber, fumed silica and aluminum hydroxide. Aluminum hydroxide is the most commonly used inorganic filler in the production of silicone rubber shed materials. It can give the insulator better electrical corrosion resistance, tracking resistance and insulation performance. However, in order to achieve satisfactory electrical performance, a large amount of aluminum hydroxide is often needed, which will damage the mechanical properties and processing properties of silicone rubber.

[0004] Chinese patent CN111808429A discloses a silicone rubber material for composite insulators and its preparation method, which improves the tracking resistance of the silicone rubber of the composite insulator by adding 100 to 300 parts of active aluminum hydroxide, but a large amount of inorganic fillers makes the material's processing performance poor. In addition, the low rubber content will also lead to the occurrence of powdering problems.

[0005] Therefore, there is an urgent need for a silicone rubber for composite insulators and a preparation method thereof to solve the above problems. Summary of the invention

[0006] The object of the present invention is to provide a silicone rubber for composite insulators and a preparation method thereof, which can reduce the filling amount of aluminum hydroxide while improving the tracking resistance of the insulator silicone rubber through the synergistic combination between a PN-Si anti-tracking aid and a silane-modified aluminum hydroxide, thereby effectively solving the problems of processability and poor mechanical properties.

[0007] To achieve the above-mentioned purpose, the present invention provides a silicone rubber for a composite insulator. The raw materials for preparation include, by weight, 20 to 80 parts of a first methyl vinyl silicone rubber raw rubber, 10 to 50 parts of a second methyl vinyl silicone rubber raw rubber, 20 to 60 parts of white carbon black, 1 to 15 parts of hydroxy silicone oil, 80 to 120 parts of aluminum hydroxide, 1 to 10 parts of PN-Si anti-leakage current tracking aid, 0.1 to 2.2 parts of a first silane coupling agent, 1 to 4 parts of dimethyl silicone oil and 0.01 to 1 part of a release agent. The raw materials for preparation of the PN-Si anti-leakage current tracking aid include a second silane coupling agent, phytic acid and melamine. The aluminum hydroxide is silane-modified aluminum hydroxide, and the particle size D50 of the aluminum hydroxide is 1 μm to 5 μm.

[0008] Compared with the prior art, the PN-Si anti-leakage tracking agent is a nano-scale non-polar material with an outer layer coated with a silane structure, which is prepared from raw materials including a second silane coupling agent, phytic acid and melamine. It has good affinity with silicone rubber, and contains three main elements, P, N, and Si, which are important for improving the anti-leakage tracking performance, and has a nano-scale layered microstructure. The present invention uses silane-modified aluminum hydroxide to cooperate with the PN-Si anti-leakage tracking agent, and combines aluminum hydroxide, a micron-scale material with a spherical particle size D50 of 2.5μm to 5μm, with the nano-scale PN-Si anti-leakage tracking agent, so that the insulator composite material can obtain better performance. First of all, this combination of micro-nano structures fills the gaps between the micron spherical structures, improves the thermal conductivity of the material, and makes it easier to diffuse the heat generated inside the insulator to the surface, which plays a role in slowing down thermal aging. Secondly, the nanosheet structure can play a very good barrier role. On the one hand, it can block the erosion of internal materials by external dirt and rainwater, so that the insulator can maintain stable hydrophobicity and hydrophobic migration performance. On the other hand, it can increase the path of water release during the thermal decomposition of aluminum hydroxide, prolong the time for water vapor to cool down and play a cooling function, and play a better role in electrical corrosion resistance. At the same time, PN-Si leakage current tracking additive can catalyze carbonization under high temperature environment to form a protective layer of Si-OC, which can block external heat and obtain a better leakage current tracking resistance grade. Finally, the synergistic effect of the two can effectively reduce the amount of aluminum hydroxide used, while ensuring qualified leakage current tracking resistance performance, and solve the problem of high filling amount, poor processing performance and mechanical properties when aluminum hydroxide is used alone.

[0009] As a preferred technical solution, the molecular weight of the first methyl vinyl silicone rubber raw rubber of the present invention is 600,000 to 700,000, and the vinyl content is 0.15% to 0.32%. The molecular weight of the second methyl vinyl silicone rubber raw rubber of the present invention is 550,000 to 650,000, and the vinyl content is 0.03% to 0.12%.

[0010] As a preferred technical solution, the white carbon black of the present invention is gas phase white carbon black, and the specific surface area of ​​the white carbon black is 200m 2 / g~300m 2 / g.

[0011] As a preferred technical solution, the viscosity of the hydroxy silicone oil of the present invention is 20 mm 2 / s~60mm 2 / s, and the hydroxyl content is 4% to 9%.

[0012] As a preferred technical solution, the release agent of the present invention is selected from at least one of magnesium stearate, zinc stearate and calcium stearate.

[0013] As a preferred technical solution, the first silane coupling agent and the second silane coupling agent of the present invention are independently selected from at least one of silane coupling agents A151, A171, A172, KH-560, KH-550, KH-570 and KH-560.

[0014] Another aspect of the present invention provides a method for preparing the aforementioned silicone rubber for composite insulators, comprising:

[0015] S1 In an inert atmosphere, the first methyl vinyl silicone rubber raw rubber, the second methyl vinyl silicone rubber raw rubber, hydroxy silicone oil and part of white carbon black are put into an internal mixer and kneaded into a mass, and then the remaining part of white carbon black is added in batches and kneaded into a mass, and then the temperature is raised to 80℃~110℃ and kneaded for 0.5h~1h, and then the temperature is raised to 155℃~165℃ under vacuum conditions and kneaded for 1h~3h to obtain the first mixed material, and the temperature is lowered for standby use;

[0016] S2: In an inert atmosphere, PN-Si anti-tracking agent, a first silane coupling agent, a release agent and a portion of aluminum hydroxide are added to the first mixed material to mix into a mass, and then the remaining portion of aluminum hydroxide is added in batches and mixed into a mass, and then the temperature is raised to 100° C. to 130° C. under vacuum conditions and mixed for 0.5 h to 1 h to obtain a second mixed material;

[0017] S3: cool the second mixed material to room temperature, then perform back-mixing and filtering.

[0018] As a preferred technical solution, the vacuum degree of the vacuum condition is 0.06MPa to 0.08MPa.

[0019] As a preferred technical solution, the preparation of the PN-Si anti-leakage tracking agent of the present invention includes: mixing the second silane coupling agent and ethanol in a molar ratio of 1:4 to 10 under a pH condition of 3 to 5 to obtain a silane hydrolyzate; mixing the phytic acid and the melamine in a molar ratio of 1:4 to 12 to obtain a mixed solution; slowly dropping the silane hydrolyzate into the mixed solution and reacting at 70°C to 90°C for 24h to 72h, then washing with water and alcohol until the filtrate is neutral and then drying to obtain the PN-Si anti-leakage tracking agent.

[0020] As a preferred technical solution, the mass fraction of ethanol in the present invention is 95%, and the phytic acid is a phytic acid aqueous solution with a mass fraction of 75%. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a scanning electron microscope image of the PN-Si anti-tracking additive prepared in Example 1 of the present invention.

[0022] Figure 2 This is a transmission electron micrograph of the PN-Si anti-tracking agent prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0023] The present invention first provides a silicone rubber for a composite insulator. The raw materials for preparation include, by weight, 20 to 80 parts of a first methyl vinyl silicone rubber raw rubber, 10 to 50 parts of a second methyl vinyl silicone rubber raw rubber, 20 to 60 parts of white carbon black, 1 to 15 parts of hydroxy silicone oil, 80 to 120 parts of aluminum hydroxide, 1 to 10 parts of PN-Si leakage current anti-tracking additive, 0.1 to 2.2 parts of a first silane coupling agent, 1 to 4 parts of dimethyl silicone oil and 0.01 to 1 part of a demolding agent.

[0024] The weight percentage of the first methyl vinyl silicone rubber raw rubber of the present invention can be, but is not limited to, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, 75 parts, and 80 parts. In some embodiments, the weight percentage of the first methyl vinyl silicone rubber raw rubber of the present invention is 50 parts to 70 parts. The molecular weight of the first methyl vinyl silicone rubber raw rubber is 600,000 to 700,000, and the vinyl content is 0.15% to 0.32%. As an example, the molecular weight of the first methyl vinyl silicone rubber raw rubber can be, but is not limited to, 600,000, 610,000, 620,000, 630,000, 640,000, 650,000, 660,000, 670,000, 680,000, 690,000, and 700,000, and the vinyl content can be, but is not limited to, 0.15%, 0.16%, 0.18%, 0.20%, 0.22%, 0.24%, 0.26%, 0.28%, 0.30%, and 0.32%. In some embodiments, the molecular weight of the first methyl vinyl silicone rubber raw rubber is 640,000, and the vinyl content is 0.21%. It is necessary to explain that the present invention has no special restrictions on the source of the first methyl vinyl silicone rubber raw rubber, and it can be purchased on the market or prepared according to conventional methods well known to those skilled in the art.

[0025] The weight proportion of the second methyl vinyl silicone rubber raw rubber of the present invention can be, but is not limited to, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, 45 parts, and 50 parts. In some embodiments, the weight proportion of the second methyl vinyl silicone rubber raw rubber of the present invention is 30 to 50 parts. The molecular weight of the second methyl vinyl silicone rubber raw rubber is 550,000 to 650,000, and the content of vinyl is 0.03% to 0.12%. As an example, the molecular weight of the second methyl vinyl silicone rubber raw rubber can be, but is not limited to, 550,000, 560,000, 570,000, 580,000, 590,000, 600,000, 610,000, 620,000, 630,000, 640,000, and 650,000, and the content of vinyl can be, but is not limited to, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.11%, and 0.12%. In some embodiments, the molecular weight of the second methyl vinyl silicone rubber is 620,000, and the vinyl content is 0.04%. It is necessary to explain that the present invention has no special restrictions on the source of the second methyl vinyl silicone rubber, which can be purchased on the market or prepared according to conventional methods known to those skilled in the art.

[0026] The weight percentage of the white carbon black of the present invention can be, but is not limited to, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, and 60 parts. In some embodiments, the weight percentage of the white carbon black of the present invention is 30 parts to 60 parts. The white carbon black can be specifically fumed white carbon black, and the specific surface area of ​​the white carbon black is 200m 2 / g~300m 2As an example, the specific surface area of ​​white carbon black can be, but is not limited to, 200 m 2 / g, 210m 2 / g, 220m 2 / g, 230m 2 / g, 240m 2 / g, 250m 2 / g, 260m 2 / g, 270m 2 / g, 280m 2 / g, 290m 2 / g、300m 2 In some embodiments, the white carbon black may be selected from HL200.

[0027] The invention comprises compounding a first methyl vinyl silicone rubber raw rubber with a high vinyl content and a second methyl vinyl silicone rubber raw rubber with a low vinyl content, and adding a methyl vinyl silicone rubber raw rubber with a specific surface area of ​​200 m 2 / g~300m 2 / g of white carbon black is used as a reinforcing filler, so that the composite insulator can obtain better mechanical properties.

[0028] The weight percentage of the hydroxy silicone oil of the present invention can be, but is not limited to, 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, and 15 parts. In some embodiments, the weight percentage of the hydroxy silicone oil of the present invention is 6 to 10 parts. The viscosity of the hydroxy silicone oil is 20 mm 2 / s~60mm 2 / s, the hydroxyl content is 4% to 9%. As an example, the viscosity of the hydroxy silicone oil can be but is not limited to 20 mm 2 / s, 25mm 2 / s, 30mm 2 / s, 35mm 2 / s, 40mm 2 / s, 45mm 2 / s, 50mm 2 / s, 55mm 2 / s, 60mm 2 / s, the hydroxyl content can be but not limited to 4%, 5%, 6%, 7%, 8%, 9%. As an example, the viscosity of hydroxy silicone oil is 30mm 2 / s, and the hydroxyl content is 9%. It is necessary to explain that the present invention has no special restrictions on the source of hydroxy silicone oil, and any hydroxy silicone oil purchased on the market or prepared according to conventional methods known to those skilled in the art can be used.

[0029] The weight proportions of the aluminum hydroxide of the present invention can be, but are not limited to, 80 parts, 90 parts, 100 parts, 110 parts, and 120 parts. The aluminum hydroxide of the present invention is silane-modified aluminum hydroxide, and the particle size D50 of the aluminum hydroxide is 1 μm to 5 μm. As an example, the particle size D50 of the aluminum hydroxide is 1 μm, 2 μm, 3 μm, 4 μm, and 5 μm. It is necessary to explain that the present invention does not have any special restrictions on the source of silane-modified aluminum hydroxide, and it can be purchased on the market or prepared according to conventional methods well known to those skilled in the art. As an example, the silane-modified aluminum hydroxide of the present invention can be at least one of IF-6, H-WF-1ST of Zibo Ruixing New Materials Co., Ltd. and HX-2 of Shandong Shibang Chemical Technology Co., Ltd.

[0030] The weight proportions of the PN-Si anti-leakage tracking agent of the present invention can be, but are not limited to, 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, and 10 parts. In some embodiments, the weight proportions of the PN-Si anti-leakage tracking agent of the present invention are 3 to 10 parts. The raw materials for preparing the PN-Si anti-leakage tracking agent of the present invention include a second silane coupling agent, phytic acid, and melamine. Specifically, the second silane coupling agent can be selected from at least one of silane coupling agents A151, A171, A172, KH-560, KH-550, KH-570, and KH-560. As an example, the second silane coupling agent can be selected from silane coupling agent A171. The PN-Si anti-leakage tracking additive prepared from the above raw materials has a nano-scale flake structure, and is used in conjunction with the micron-scale spherical silane-modified aluminum hydroxide with a particle size of 1μm to 5μm of the present invention to reduce the amount of silane-modified aluminum hydroxide used and obtain excellent anti-leakage tracking effect.

[0031] The weight proportion of the first silane coupling agent of the present invention may be, but is not limited to, 0.1, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6, 1.8, 2.0, and 2.2. In some embodiments, the weight proportion of the first silane coupling agent is 0.8 to 1.2. The first silane coupling agent may be selected from at least one of silane coupling agents A151, A171, A172, KH-560, KH-550, KH-570, and KH-560. As an example, the first silane coupling agent of the present invention is selected from A171. The specific types of the first silane coupling agent and the second silane coupling agent of the present invention may be the same or different.

[0032] The weight parts of the dimethyl silicone oil of the present invention can be, but are not limited to, 1 part, 1.1 parts, 1.2 parts, 1.3 parts, 1.4 parts, 1.5 parts, 1.6 parts, 1.7 parts, 1.8 parts, 1.9 parts, 2 parts, 3 parts, and 4 parts. The weight parts of the release agent of the present invention can be, but are not limited to, 0.01 parts, 0.05 parts, 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, and 1 part. In some embodiments, the weight parts of the release agent are 0.5 to 1 parts. The release agent can be selected from at least one of magnesium stearate, zinc stearate, and calcium stearate. As an example, the release agent of the present invention is zinc stearate.

[0033] The present invention also provides a method for preparing the aforementioned silicone rubber for composite insulators, comprising:

[0034] S1 In an inert atmosphere, the first methyl vinyl silicone rubber raw rubber, the second methyl vinyl silicone rubber raw rubber, hydroxy silicone oil and part of white carbon black are put into an internal mixer and mixed into a mass, and then the remaining part of white carbon black is added in batches and mixed into a mass, and then the temperature is raised to 80℃~110℃ and mixed for 0.5h~1h, and then the temperature is raised to 155℃~165℃ under vacuum conditions and mixed for 1h~3h to obtain the first mixed material, and the temperature is lowered for standby use, wherein the vacuum degree of the vacuum condition is 0.06MPa~0.08MPa;

[0035] S2: In an inert atmosphere, PN-Si anti-tracking agent, a first silane coupling agent, a release agent, dimethyl silicone oil and part of aluminum hydroxide are added to the first mixed material to mix into a mass, and then the remaining part of aluminum hydroxide is added in batches and mixed into a mass, and then the temperature is raised to 100° C. to 130° C. under vacuum conditions and mixed for 0.5 h to 1 h to obtain a second mixed material, wherein the vacuum degree of the vacuum condition is 0.06 MPa to 0.08 MPa;

[0036] S3: cool the second mixed material to room temperature, then perform back-mixing and filtering.

[0037] In some embodiments, part of the white carbon black may be 40% white carbon black, and the remaining white carbon black may be put into the internal mixer in batches of 30%, 15%, and 15%, but is not limited thereto. In some embodiments, part of the aluminum hydroxide may be 30% aluminum hydroxide, and the remaining aluminum hydroxide may be put into the internal mixer in batches of 30%, 20%, 10%, and 10%, but is not limited thereto.

[0038] The preparation of the PN-Si anti-leakage tracking aid of the present invention comprises: mixing a second silane coupling agent and ethanol at a molar ratio of 1:4-10 under a pH value of 3-5 to obtain a silane hydrolyzate, wherein the mass fraction of the ethanol is 95%; mixing phytic acid and melamine at a molar ratio of 1:4-12 to obtain a mixed solution, wherein the phytic acid is a phytic acid aqueous solution with a mass fraction of 75%; slowly dropping the siloxane hydrolyzate into the mixed solution and reacting at 70-90°C for 24-72 hours, then washing with water and alcohol until the filtrate is neutral, and then drying to obtain the PN-Si anti-leakage tracking aid.

[0039] Specifically, the molar ratio of the second silane coupling agent to ethanol can be, but is not limited to, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10. In some embodiments, the molar ratio of the second silane coupling agent to ethanol is 1:8. The molar ratio of phytic acid to melamine can be, but is not limited to, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:11, 1:12. In some embodiments, the molar ratio of phytic acid to melamine is 1:6.

[0040] In order to better illustrate the purpose, technical scheme and beneficial effects of the present invention, the present invention will be further described below in conjunction with specific embodiments. It should be noted that the following implementation method is a further explanation of the present invention and should not be used as a limitation of the present invention.

[0041] Among the raw materials used in the embodiment of the present invention, the molecular weight of the first methyl vinyl silicone rubber raw rubber A is 640,000, and the vinyl content is 0.21%; the molecular weight of the first methyl vinyl silicone rubber raw rubber B is 680,000, and the vinyl content is 0.28%; the molecular weight of the second methyl vinyl silicone rubber raw rubber A is 620,000, and the vinyl content is 0.04%; the molecular weight of the second methyl vinyl silicone rubber raw rubber B is 580,000, and the vinyl content is 0.06%; the viscosity of the hydroxy silicone oil is 30mm 2 / s, hydroxyl content is 9%; silane-modified aluminum hydroxide A is IF-6 from Zibo Ruixing New Materials Co., Ltd., and silane-modified aluminum hydroxide B is HX-2 from Shandong Shibang Chemical Technology Co., Ltd. The other raw materials not described here can be obtained from common commercial sources.

[0042] Example 1

[0043] The present embodiment provides a silicone rubber for a composite insulator. The raw materials for preparing the silicone rubber include, by weight, 60 parts of a first methyl vinyl silicone rubber raw rubber A, 40 parts of a second methyl vinyl silicone rubber raw rubber A, 35 parts of fumed silica HL200, 7 parts of hydroxy silicone oil, 80 parts of silane-modified aluminum hydroxide A, 9 parts of a PN-Si anti-leakage tracking agent, 0.8 parts of a silane coupling agent A171, 1 part of dimethyl silicone oil and 1 part of zinc stearate. The raw materials for preparing the PN-Si anti-leakage tracking agent include a silane coupling agent A171, phytic acid and melamine.

[0044] This embodiment also provides a method for preparing the silicone rubber, comprising:

[0045] S1 In an inert atmosphere, 60 parts of the first methyl vinyl silicone rubber raw rubber A, 40 parts of the second methyl vinyl silicone rubber raw rubber A, 7 parts of hydroxy silicone oil and 14 parts of fumed silica HL200 are put into an internal mixer and mixed into a mass, and then the remaining part of the fumed silica HL200 is added in batches according to 10.5 parts, 5.25 parts and 5.25 parts and mixed into a mass, and then the temperature is raised to 80°C to 110°C and mixed for 1h, and then the temperature is raised to 155°C to 165°C under a vacuum degree of 0.06MPa to 0.08MPa and mixed for 3h to obtain a first mixed material, and the temperature is lowered for standby use;

[0046] S2: In an inert atmosphere, 9 parts of PN-Si anti-tracking agent, 0.8 parts of silane coupling agent A171, 1 part of zinc stearate, 1 part of dimethyl silicone oil and 24 parts of silane-modified aluminum hydroxide A are added to the first mixed material to mix into a mass, and then the remaining part of the silane-modified aluminum hydroxide A is added in batches according to 24 parts, 16 parts, 8 parts and 8 parts and mixed into a mass, and then the temperature is raised to 100°C to 130°C under a vacuum degree of 0.06MPa to 0.08MPa and mixed for 1h to obtain a second mixed material;

[0047] S3 cools the second mixed material to room temperature, then performs back-mixing and filtering to obtain the silicone rubber for composite insulators.

[0048] In this embodiment, the preparation of the PN-Si anti-leakage tracking agent includes: mixing the silane coupling agent A171 and the ethanol solution with a mass fraction of 95% at a molar ratio of 1:8 under the condition of pH 4 to obtain a silane hydrolyzate; mixing the phytic acid aqueous solution with a mass fraction of 75% and melamine at a molar ratio of 1:6 to obtain a mixed solution; slowly dropping the siloxane hydrolyzate into the mixed solution, stirring and mixing thoroughly, reacting at 80° C. for 48 hours, and then washing with water and alcohol until the filtrate is neutral and then drying to obtain the PN-Si anti-leakage tracking agent, wherein, Figure 1 and Figure 2 The scanning electron microscope image and transmission electron microscope image of the PN-Si anti-tracking agent prepared in this example are respectively shown, proving that it has a nano-scale flaky structure.

[0049] Example 2

[0050] The present embodiment provides a silicone rubber for a composite insulator. The raw materials for preparing the silicone rubber include, by weight, 60 parts of a first methyl vinyl silicone rubber raw rubber A, 40 parts of a second methyl vinyl silicone rubber raw rubber A, 35 parts of fumed silica HL200, 7 parts of hydroxy silicone oil, 90 parts of silane-modified aluminum hydroxide A, 7 parts of PN-Si anti-leakage tracking agent, 0.9 parts of silane coupling agent A171, 1.2 parts of dimethyl silicone oil and 1 part of zinc stearate. The raw materials for preparing the PN-Si anti-leakage tracking agent include silane coupling agent A171, phytic acid and melamine.

[0051] The preparation method of the composite insulator silicone rubber and the PN-Si anti-tracking agent in this embodiment is prepared by referring to the preparation method in Example 1.

[0052] Example 3

[0053] The present embodiment provides a silicone rubber for a composite insulator. The raw materials for preparation include, by weight, 60 parts of a first methyl vinyl silicone rubber raw rubber A, 40 parts of a second methyl vinyl silicone rubber raw rubber A, 35 parts of fumed silica HL200, 7 parts of hydroxy silicone oil, 100 parts of silane-modified aluminum hydroxide A, 5 parts of PN-Si anti-leakage tracking agent, 1 part of silane coupling agent A171, 1.4 parts of dimethyl silicone oil and 1 part of zinc stearate. The raw materials for preparation of the PN-Si anti-leakage tracking agent include silane coupling agent A171, phytic acid and melamine.

[0054] The preparation method of the composite insulator silicone rubber and the PN-Si anti-tracking agent in this embodiment is prepared by referring to the preparation method in Example 1.

[0055] Example 4

[0056] The present embodiment provides a silicone rubber for a composite insulator. The raw materials for preparation include, by weight, 60 parts of a first methyl vinyl silicone rubber raw rubber A, 40 parts of a second methyl vinyl silicone rubber raw rubber A, 35 parts of fumed silica HL200, 7 parts of hydroxy silicone oil, 120 parts of silane-modified aluminum hydroxide A, 5 parts of PN-Si anti-leakage tracking agent, 1.2 parts of silane coupling agent A171, 1.8 parts of dimethyl silicone oil and 1 part of zinc stearate. The raw materials for preparing the PN-Si anti-leakage tracking agent include silane coupling agent A171, phytic acid and melamine.

[0057] The preparation method of the composite insulator silicone rubber and the PN-Si anti-tracking agent in this embodiment is prepared by referring to the preparation method in Example 1.

[0058] Example 5

[0059] The present embodiment provides a silicone rubber for a composite insulator. The raw materials for preparation include, by weight, 60 parts of a first methyl vinyl silicone rubber raw rubber A, 40 parts of a second methyl vinyl silicone rubber raw rubber A, 35 parts of fumed silica HL200, 7 parts of hydroxy silicone oil, 120 parts of silane-modified aluminum hydroxide A, 3 parts of PN-Si anti-leakage tracking agent, 1.2 parts of silane coupling agent A171, 1.8 parts of dimethyl silicone oil and 1 part of zinc stearate. The raw materials for preparing the PN-Si anti-leakage tracking agent include silane coupling agent A171, phytic acid and melamine.

[0060] The preparation method of the composite insulator silicone rubber and the PN-Si anti-tracking agent in this embodiment is prepared by referring to the preparation method in Example 1.

[0061] Example 6

[0062] The present embodiment provides a silicone rubber for a composite insulator. The raw materials for preparing the silicone rubber include, by weight, 50 parts of a first methyl vinyl silicone rubber raw rubber B, 50 parts of a second methyl vinyl silicone rubber raw rubber B, 45 parts of fumed silica HL200, 9 parts of hydroxy silicone oil, 80 parts of silane-modified aluminum hydroxide B, 7 parts of a PN-Si anti-leakage tracking agent, 0.8 parts of a silane coupling agent A172, 1 part of dimethyl silicone oil and 1 part of calcium stearate. The raw materials for preparing the PN-Si anti-leakage tracking agent include a silane coupling agent A171, phytic acid and melamine.

[0063] The preparation method of the composite insulator silicone rubber and the PN-Si anti-tracking agent in this embodiment is prepared by referring to the preparation method in Example 1.

[0064] Comparative Example 1

[0065] This comparative example provides a silicone rubber for a composite insulator. The preparation raw materials include, by weight, 60 parts of a first methyl vinyl silicone rubber raw rubber A, 40 parts of a second methyl vinyl silicone rubber raw rubber A, 35 parts of fumed silica HL200, 7 parts of hydroxy silicone oil, 120 parts of silane-modified aluminum hydroxide A, 1.2 parts of silane coupling agent A171, 1.8 parts of dimethyl silicone oil and 1 part of zinc stearate.

[0066] The preparation method of the composite insulator silicone rubber in this comparative example is prepared by referring to the preparation method of Example 1.

[0067] Comparative Example 2

[0068] This comparative example provides a silicone rubber for a composite insulator. The preparation raw materials include, by weight, 60 parts of a first methyl vinyl silicone rubber raw rubber A, 40 parts of a second methyl vinyl silicone rubber raw rubber A, 35 parts of fumed silica HL200, 7 parts of hydroxy silicone oil, 170 parts of silane-modified aluminum hydroxide A, 1.7 parts of silane coupling agent A171, 2.8 parts of dimethyl silicone oil and 1 part of zinc stearate.

[0069] The preparation method of the composite insulator silicone rubber in this comparative example is prepared by referring to the preparation method of Example 1.

[0070] Comparative Example 3

[0071] This comparative example provides a silicone rubber for a composite insulator. The preparation raw materials include, by weight, 60 parts of a first methyl vinyl silicone rubber raw rubber A, 40 parts of a second methyl vinyl silicone rubber raw rubber A, 35 parts of fumed silica HL200, 7 parts of hydroxy silicone oil, 210 parts of silane-modified aluminum hydroxide A, 2.1 parts of silane coupling agent A171, 3.6 parts of dimethyl silicone oil and 1 part of zinc stearate.

[0072] The preparation method of the composite insulator silicone rubber in this comparative example is prepared by referring to the preparation method of Example 1.

[0073] Comparative Example 4

[0074] The comparative example provides a silicone rubber for a composite insulator. The raw materials for preparing the silicone rubber include, by weight, 60 parts of a first methyl vinyl silicone rubber raw rubber A, 40 parts of a second methyl vinyl silicone rubber raw rubber A, 35 parts of fumed silica HL200, 7 parts of hydroxy silicone oil, 120 parts of aluminum hydroxide, 3 parts of PN-Si anti-leakage tracking agent, 1.2 parts of silane coupling agent A171, 1.8 parts of dimethyl silicone oil and 1 part of zinc stearate. The raw materials for preparing the PN-Si anti-leakage tracking agent include silane coupling agent A171, phytic acid and melamine.

[0075] The preparation method of the composite insulator silicone rubber and the PN-Si anti-tracking agent in this comparative example is prepared by referring to the preparation method in Example 1.

[0076] 1% of di-2-pentane vulcanizing agent was added to the silicone rubber for composite insulators prepared in Examples 1 to 6 and Comparative Examples 1 to 4, respectively, and vulcanized at 170° C. to prepare samples. Performance tests were performed according to the standards in Table 1. The test results are shown in Table 2.

[0077] Table 1 Performance test standards of silicone rubber for composite insulators prepared in Examples 1 to 6 and Comparative Examples 1 to 4

[0078]

[0079]

[0080] Table 2 Performance test results of silicone rubber for composite insulators prepared in Examples 1 to 6 and Comparative Examples 1 to 4

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[0082] Specifically, see the performance test results in Table 2. From the performance test results of Examples 1 to 4, it can be found that with the increase in the filling amount of silane-modified aluminum hydroxide, the mechanical properties of the composite insulator glue decrease. From Comparative Examples 1 to 3, it can be seen that when silane-modified aluminum hydroxide is used alone, Comparative Example 3 needs to add 210 parts to meet the TMA4.5 level of resistance to leakage current tracking. Further comparing Comparative Example 3 with Example 2, when reaching the same level of resistance to leakage current tracking, the tensile strength, elongation, and tear strength of Comparative Example 3 decreased by 42.2%, 34.1%, and 35.5%, respectively, and the plasticity increased by 46.8%, indicating that the addition of the PN-Si leakage current tracking aid of the present invention can significantly improve the resistance to leakage current tracking of the composite insulator glue, and can achieve the effect of reducing the filling amount of aluminum hydroxide, thereby enabling the silicone rubber for composite insulators to obtain better processing performance. By comparing Example 4, Example 5 and Comparative Example 1, it can be seen that when the filling amount of aluminum hydroxide is the same, the addition of PN-Si anti-leakage tracking aid can improve the thermal conductivity of the composite insulator glue. At the same time, as the amount of PN-Si anti-leakage tracking aid added increases, the thermal conductivity increases and the electrocorrosion depth decreases, indicating that the PN-Si anti-leakage tracking aid plays an important role in improving the anti-leakage tracking performance of the composite insulator glue. By comparing the performance of Example 5 and Comparative Example 4, it can be seen that when silane-modified aluminum hydroxide is replaced with ordinary aluminum hydroxide, the tensile strength of the composite insulator glue decreases by 22.7%, the breakdown strength decreases by 16.3%, and it cannot pass the anti-leakage tracking TMA4.5 grade test, indicating that compared with ordinary aluminum hydroxide, silane-modified aluminum hydroxide exhibits better anti-leakage tracking performance.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention is described in detail with reference to the preferred embodiments, it is not limited to those listed in the embodiments. Those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. Silicone rubber for composite insulators, characterized in that: The raw materials for preparation include 20 to 80 parts of a first methyl vinyl silicone rubber raw rubber, 10 to 50 parts of a second methyl vinyl silicone rubber raw rubber, 20 to 60 parts of white carbon black, 1 to 15 parts of hydroxy silicone oil, 80 to 120 parts of aluminum hydroxide, 1 to 10 parts of PN-Si anti-leakage current tracking agent, 0.1 to 2.2 parts of a first silane coupling agent, 1 to 4 parts of dimethyl silicone oil and 0.01 to 1 part of a demolding agent. The raw materials for preparation of the PN-Si anti-leakage current tracking agent include a second silane coupling agent, phytic acid and melamine. The aluminum hydroxide is silane-modified aluminum hydroxide, and the particle size D50 of the aluminum hydroxide is 1 μm to 5 μm.

2. The silicone rubber for composite insulator according to claim 1, characterized in that: The molecular weight of the first methyl vinyl silicone rubber raw rubber is 600,000-700,000, and the vinyl content is 0.15%-0.32%. The molecular weight of the second methyl vinyl silicone rubber raw rubber is 550,000-650,000, and the vinyl content is 0.03%-0.12%.

3. The silicone rubber for composite insulator according to claim 1, characterized in that: The white carbon black is gas phase white carbon black, and the specific surface area of ​​the white carbon black is 200m 2 / g~300m 2 / g.

4. The silicone rubber for composite insulator according to claim 1, characterized in that: The viscosity of the hydroxy silicone oil is 20 mm 2 / s~60mm 2 / s, and the hydroxyl content is 4% to 9%.

5. The silicone rubber for composite insulator according to claim 1, characterized in that: The release agent is selected from at least one of magnesium stearate, zinc stearate and calcium stearate.

6. The silicone rubber for composite insulator according to claim 1, characterized in that: The first silane coupling agent and the second silane coupling agent are each independently selected from at least one of silane coupling agents A151, A171, A172, KH-560, KH-550, KH-570 and KH-580.

7. The method for preparing the silicone rubber for composite insulator according to any one of claims 1 to 6, comprising: S1: In an inert atmosphere, the first methyl vinyl silicone rubber raw rubber, the second methyl vinyl silicone rubber raw rubber, the hydroxy silicone oil and part of the white carbon black are put into an internal mixer and kneaded into a mass, and then the remaining part of the white carbon black is added in batches and kneaded into a mass, and then the temperature is raised to 80°C to 110°C and kneaded for 0.5h to 1h, and then the temperature is raised to 155°C to 165°C under vacuum conditions and kneaded for 1h to 3h to obtain a first mixed material, and the temperature is lowered for standby use; S2: In an inert atmosphere, the PN-Si anti-tracking agent, the first silane coupling agent, the release agent, dimethyl silicone oil and part of the aluminum hydroxide are added to the first mixed material to mix into a mass, and then the remaining part of the aluminum hydroxide is added in batches and mixed into a mass, and then the temperature is raised to 100° C. to 130° C. under vacuum conditions and mixed for 0.5 h to 1 h to obtain a second mixed material; S3: cool the second mixed material to room temperature, then perform back-mixing and filtering.

8. The method for preparing silicone rubber for composite insulators according to claim 7, characterized in that: The vacuum degree of the vacuum condition is 0.06MPa to 0.08MPa.

9. The method for preparing silicone rubber for composite insulators according to claim 7, characterized in that: The preparation of the PN-Si anti-leakage tracking agent includes: mixing the second silane coupling agent and ethanol in a molar ratio of 1:4-10 under a pH condition of 3-5 to obtain a silane hydrolyzate; mixing the phytic acid and the melamine in a molar ratio of 1:4-12 to obtain a mixed solution; slowly dropping the silane hydrolyzate into the mixed solution and reacting at 70°C-90°C for 24h-72h, then washing with water and alcohol until the filtrate is neutral and then drying to obtain the PN-Si anti-leakage tracking agent.

10. The method for preparing silicone rubber for composite insulators according to claim 9, characterized in that: The mass fraction of the ethanol is 95%, and the phytic acid is a phytic acid aqueous solution with a mass fraction of 75%.

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