Htv silicone rubber material and its use
By adjusting the composition and filler ratio of HTV silicone rubber material, the thermal conductivity and dielectric properties were optimized, solving the problem of abnormal heating of composite insulators under high humidity and heat conditions, and achieving better aging resistance and mechanical strength.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- TSINGHUA SHENZHEN INTERNATIONAL GRADUATE SCHOOL
- Filing Date
- 2023-11-29
- Publication Date
- 2026-07-14
AI Technical Summary
Existing high-temperature vulcanized silicone rubber materials are prone to abnormal heating and surface deterioration in high humidity and heat environments, leading to a decline in the performance of composite insulators.
By adjusting the blending of methyl vinyl silicone rubber with aluminum hydroxide of different particle sizes and surface activities, the types and ratios of fillers are optimized, the amount of inorganic fillers is reduced, a thermally conductive path is built, the rubber content and dielectric properties are increased, and specific additives are added to improve the resistance to humid heat aging.
It significantly reduces water absorption and dielectric loss, improves resistance to damp heat aging, prevents abnormal heating of composite insulators in high humidity and heat environments, and maintains good electromechanical performance.
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Figure CN117417639B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of high voltage external insulation technology, and in particular to an HTV silicone rubber material and its applications. Background Technology
[0002] Composite insulators possess excellent resistance to flashover and can adapt well to various polluted environments, leading to their widespread application throughout China. However, with the dramatic increase in usage, reports of defects such as abnormal overheating and surface powdering in composite insulators are becoming increasingly common, especially in southern regions with higher temperatures and humidity, where the overheating phenomenon is more severe. Currently operating composite insulators are mostly high-temperature vulcanized silicone rubber insulators (HTV), with their skirts and sheaths made of high-temperature vulcanized silicone rubber. The materials of the skirts and sheaths have a significant impact on the operating characteristics of composite insulators.
[0003] Abnormal heating and aging performance are mainly related to the microstructure of HTV silicone rubber materials and the type and proportion of fillers. Preliminary research indicates that compared to normally operating insulators, the surface microstructure of the HTV silicone rubber shed material in line heating composite insulators is loose and porous, and the dielectric loss power increases significantly after silicone rubber absorbs moisture. Experiments have found that HTV silicone rubber materials with low rubber content are more prone to aging, exhibiting filler precipitation and a loose structure on the surface. Preliminary research also found that the HTV silicone rubber material used in heating composite insulators has a higher water absorption rate, leading to a significant increase in dielectric loss power after moisture absorption, resulting in abnormal heating and surface deterioration of the HTV silicone rubber material under high temperature and high humidity environments. Summary of the Invention
[0004] To address the technical problem of abnormal heating and surface deterioration of HTV silicone rubber materials in existing ultra-high voltage composite insulators under high humidity and heat environments, the primary objective of this invention is to provide an HTV silicone rubber material with low dielectric loss and excellent resistance to humid heat aging.
[0005] Another object of the present invention is to provide the application of the above-mentioned HTV silicone rubber material.
[0006] This invention is achieved through the following technical solution:
[0007] An HTV silicone rubber material, by weight, comprises the following components:
[0008]
[0009]
[0010] In some embodiments, the product comprises, by weight, the following components:
[0011]
[0012] In some embodiments, the methyl vinyl silicone rubber is composed of two base rubbers with vinyl contents of 0.04% and 0.22%, and the vinyl content of the compounded methyl vinyl silicone rubber reaches 0.12-0.15%.
[0013] In some embodiments, the reinforcing agent is selected from one or more combinations of nano-silica and vinyl MQ silicone resin.
[0014] In some embodiments, the aluminum hydroxide is selected from aluminum hydroxide A with untreated surface and a particle size D50 of 1 to 2 μm and aluminum hydroxide B with surface silanization treatment and a particle size D50 of 3 to 5 μm.
[0015] In some embodiments, the weight ratio of aluminum hydroxide A to aluminum hydroxide B is 5:1 to 8:1.
[0016] In some embodiments, the other additives, by weight, include 2 to 4 parts coupling agent, 4 to 8 parts colorant, 1 to 3 parts vulcanizing agent and 4 to 8 parts silicone oil.
[0017] In some embodiments, the coupling agent is selected from silane coupling agents containing amino, methoxy, and vinyl functional groups; the colorant is selected from silica gel with an iron oxide content of more than 70% by mass; the vulcanizing agent is selected from bis(2,5-dimethyl)sulfide; and the silicone oil is selected from a compound of hydroxyl silicone oil and hydrogen-containing silicone oil.
[0018] This invention also proposes the application of the above-mentioned HTV silicone rubber material in ultra-high voltage composite insulators under high humidity and heat conditions.
[0019] The beneficial effects of this invention compared to the prior art include:
[0020] This invention prepares an HTV silicone rubber material by compounding aluminum hydroxide with specific amounts and different particle sizes and surface activities with specific amounts of methyl vinyl silicone rubber and reinforcing agents, and supplementing with specific amounts of other additives. Compared with existing HTV silicone rubber materials used in UHV composite insulators under high humidity and heat conditions, the prepared HTV silicone rubber material has a significantly higher rubber content, significantly lower water absorption and dielectric loss, and excellent resistance to humid heat aging, effectively preventing abnormal heating phenomena in UHV composite insulators under high humidity and heat conditions.
[0021] Other beneficial effects of the embodiments of the present invention will be further described below. Attached Figure Description
[0022] Figure 1a This is a schematic diagram showing the water absorption rate and boiling time of commercially available HTV silicone rubber materials.
[0023] Figure 1bThis is a schematic diagram showing the water absorption rate and boiling time of the HTV silicone rubber material in an embodiment of the present invention.
[0024] Figure 2a This is a schematic diagram of the surface morphology of the HTV silicone rubber material before aging in an embodiment of the present invention.
[0025] Figure 2b This is a schematic diagram of the surface morphology of HTV silicone rubber material after water boiling and aging in an embodiment of the present invention.
[0026] Figure 3a This is a schematic diagram of the surface morphology of commercially available HTV silicone rubber material before aging.
[0027] Figure 3b This is a schematic diagram of the surface morphology of commercially available HTV silicone rubber material after boiling and aging.
[0028] Figure 4 This is a schematic diagram comparing the tensile strength and boiling time data of HTV silicone rubber material and commercially available HTV silicone rubber material in the embodiments of the present invention.
[0029] Figure 5 This is a schematic diagram comparing the elongation at break and boiling time data of HTV silicone rubber material and commercially available HTV silicone rubber material in the embodiments of the present invention.
[0030] Figure 6 This is a schematic diagram comparing the dielectric loss tangent of HTV silicone rubber material and commercially available HTV silicone rubber material in the embodiments of the present invention with the data of boiling time.
[0031] Figure 7 This is a schematic diagram of the HTV silicone rubber material after the tracking resistance test in an embodiment of the present invention.
[0032] Figure 8 This is a schematic diagram of the tracking resistance test results of commercially available HTV silicone rubber material. Detailed Implementation
[0033] The present invention will be further described below with reference to the accompanying drawings and preferred embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.
[0034] It should be noted that the directional terms such as left, right, up, down, top, and bottom used in this embodiment are only relative concepts or are based on the normal use of the product, and should not be considered as restrictive.
[0035] Traditional HTV silicone rubber is made from methyl vinyl siloxane as raw rubber, with added reinforcing agents (such as silica), flame retardants (ATH, aluminum hydroxide), and colorants, and crosslinked with peroxide as a crosslinking agent through high-temperature vulcanization. ATH is the most abundant inorganic filler. To ensure that HTV silicone rubber materials for composite insulators pass the tracking resistance test, the amount of ATH added is often more than 120 phr (parts per hundred grams). However, excessive ATH can affect the stable structure and hydrophobic properties of the silicone rubber matrix. In high-temperature and high-humidity environments, the microscopic interface between ATH and silicone rubber significantly impacts the dielectric loss of the composite material, leading to abnormal heating and surface deterioration of the HTV silicone rubber material under these conditions.
[0036] Therefore, improving the thermal conductivity and reducing dielectric loss of HTV silicone rubber materials used in composite insulators can effectively suppress abnormal heating. Simultaneously, reducing the amount of flame retardant ATH to increase the rubber content of the HTV silicone rubber material can effectively improve its aging resistance and prevent surface structure deterioration and moisture intrusion. This invention proposes an HTV silicone rubber material that solves the problems of abnormal heating and surface deterioration in HTV insulation materials under high humidity and heat conditions. While ensuring the electromechanical properties of the composite material, it reduces the amount of ATH used and reduces interface effects. While meeting the requirements for resistance to electrolytic corrosion, the inorganic filler ratio is optimized by reducing inorganic fillers, resulting in a composite material with low dielectric loss and excellent resistance to humid heat aging. Compared to traditional HTV silicone rubber materials for special insulation, the HTV silicone rubber material of this invention has a 29% higher rubber content and excellent resistance to humid heat aging, effectively preventing abnormal heating in ultra-high voltage composite insulators under high humidity and heat conditions.
[0037] The working principle is as follows: This invention improves upon the HTV silicone rubber material used in existing composite insulators for external insulation. Its purpose is to meet the electromechanical performance requirements of composite insulator skirt sheath materials, especially in terms of resistance to electrical erosion. Based on the synergistic effect of silica and alumina at high temperatures, the rubber content is increased, and the type and ratio of fillers are optimized to improve the internal structure of the composite material. This achieves the suppression of deterioration and abnormal heating of composite insulators in high humidity and heat environments from three aspects: inhibiting moisture intrusion, reducing dielectric loss, and improving heat dissipation characteristics.
[0038] In this invention, by compounding ATH with different particle sizes and surface activities, a thermally conductive pathway is effectively built inside the composite material, thereby improving the thermal conductivity. By controlling the ratio of the main filler silica and ATH and applying additives such as iron oxide, the heat resistance and electrolytic corrosion resistance of silicone rubber are improved, thereby reducing the application of inorganic fillers.
[0039] Water absorption rate test method: The water absorption rate test refers to GB / T 1034-2008. The test sample is a circular disc with a diameter of 50 mm and a thickness of 2 mm. Before the test, the test samples of both materials are dried in an oven at 50℃ until the sample mass no longer changes, then immersed in deionized water at room temperature. After the test time is reached, the samples are removed and weighed using a balance with an accuracy of 0.1 mg. The water absorption rate w(t) is defined as:
[0040]
[0041] In the formula, m0 is the mass of the sample before water absorption, m t Let t be the mass of the sample after it absorbs water.
[0042] Example 1:
[0043] The HTV silicone rubber material in Example 1 of this invention is composed of the following raw materials by mass fraction: 100 parts of compounded methyl vinyl silicone rubber, 30 parts of reinforcing agent, 80 parts of compounded aluminum hydroxide, and 18 parts of other additives, including 3 parts of silane coupling agent, 6 parts of colorant, 2 parts of vulcanizing agent, and 6 parts of silicone oil. The methyl vinyl silicone rubber is composed of two base rubbers with vinyl contents of 0.04% and 0.22%, respectively, resulting in a vinyl content of 0.12%-0.15%. The reinforcing agent is a combination of nano-silica and nano-fumed silica (nano-silica). The aluminum hydroxide is a mixture of type A (untreated with a particle size D50 of 1 μm) and type B (silylated with a particle size D50 of 4 μm). The weight ratio of aluminum hydroxide A to aluminum hydroxide B is 6:1. The compounded silane coupling agent contains functional groups such as amino, methoxy, and vinyl groups, with a specific composition and ratio of A151:A171:KH550:KH560 = 1.5:1:1.2:1.1. The colorant is a red masterbatch, which is a silica gel with an iron oxide content of over 70% and good dispersibility. The vulcanizing agent is a bis(2,5)vulcanizing agent, and the silicone oil is a mixture of hydroxyl silicone oil and hydrogen-containing silicone oil.
[0044] This invention also provides the application of the above-mentioned HTV silicone rubber material in ultra-high voltage composite insulators under high humidity and heat conditions.
[0045] The method for preparing HTV silicone rubber material suitable for high humidity and heat environments according to embodiments of the present invention includes the following steps:
[0046] (1) Place various untreated powders in a vacuum drying oven and bake at a high temperature of 100°C or above for 3-4 hours. The powders are specifically reinforcing agents nano-silica and aluminum hydroxide.
[0047] (2) The weighed methyl vinyl silicone rubber raw rubber, nano silica and compound aluminum hydroxide are kneaded in a kneader in a certain proportion; the powder should be added in batches to ensure that the base rubber and powder are fully integrated. After the feeding process is completed, knead for another 0.5 to 1 hour; then add other additives (red masterbatch, silane coupling agent) to the kneader, vacuum knead at a vacuum degree of 0.15 MPa and a temperature of 150°C for 2.5 hours to obtain the compound rubber;
[0048] (3) Wrap the compound rubber on the open mill, add other additives (vulcanizing agent), pass through thin mill, and then place the sheet on the flat vulcanizing machine for vulcanization. At 175°C and 11MPa pressure, the vulcanization time is 12min to obtain silicone rubber material.
[0049] (4) The above-mentioned silicone rubber material and the pre-baked core rod coated with adhesive are placed in a vulcanizing mold and molded at 180°C and 15MPa for 18 minutes to obtain the required silicone rubber shed for ultra-high voltage composite insulators.
[0050] Performance tests and accelerated aging tests were conducted on the prepared samples, and the results were compared with those of commercially available ordinary UHV HTV silicone rubber materials. The water absorption rate and boiling time data are as follows: Figure 1a and Figure 1b As shown in Table 1.
[0051] Example 2:
[0052] The HTV silicone rubber material in Example 2 of this invention is composed of the following raw materials by mass fraction: 100 parts of compounded methyl vinyl silicone rubber, 25 parts of reinforcing agent, 90 parts of compounded aluminum hydroxide, and 11 parts of other additives, including 4 parts of silane coupling agent, 4 parts of colorant, 3 parts of vulcanizing agent, and 4 parts of silicone oil. The methyl vinyl silicone rubber is composed of two base rubbers with vinyl contents of 0.04% and 0.22%, respectively, resulting in a vinyl content of 0.15%. The reinforcing agent is a combination of nano-silica and nano-fumed silica (nano-silica). The aluminum hydroxide is a mixture of type A (untreated with a particle size D50 of 2 μm) and type B (silylated with a particle size D50 of 3 μm). The weight ratio of aluminum hydroxide A to aluminum hydroxide B is 5:1. The compounded silane coupling agent contains functional groups such as amino, methoxy, and vinyl groups. The colorant is a red masterbatch, which is silica gel with an iron oxide content of over 70% and good dispersibility. The vulcanizing agent is a bis(2,5)vulcanizing agent, and the silicone oil is a mixture of hydroxyl silicone oil and hydrogen-containing silicone oil. The preparation method is the same as in Example 1. Performance tests and artificial accelerated aging tests were carried out on the prepared samples, and the results were compared with those of commercially available ordinary UHV HTV silicone rubber materials. The water absorption rate and boiling time data are shown in Table 1.
[0053] Example 3:
[0054] The HTV silicone rubber material in Example 3 of this invention is composed of the following raw materials by mass fraction: 100 parts of compounded methyl vinyl silicone rubber, 40 parts of reinforcing agent, 70 parts of compounded aluminum hydroxide, and 23 parts of other additives, including 2 parts of silane coupling agent, 8 parts of colorant, 1 part of vulcanizing agent, and 8 parts of silicone oil. The methyl vinyl silicone rubber is composed of two base rubbers with vinyl contents of 0.04% and 0.22%, respectively, resulting in a vinyl content of 0.12%. The reinforcing agent is a combination of nano-silica and nano-fumed silica (nano-silica). The aluminum hydroxide is a combination of type A (untreated with a particle size D50 of 1 μm) and type B (silylated with a particle size D50 of 5 μm). The weight ratio of aluminum hydroxide A to aluminum hydroxide B is 8:1. The compounded silane coupling agent contains functional groups such as amino, methoxy, and vinyl groups. The colorant is a red masterbatch, which is silica gel with an iron oxide content of over 70% and good dispersibility. The vulcanizing agent is a bis(2,5-dimethyl)vulcanizing agent, and the silicone oil is a compound of hydroxyl silicone oil and hydrogen-containing silicone oil. The preparation method is the same as in Example 1. Performance tests and accelerated aging tests were conducted on the prepared samples, and the results were compared with those of commercially available ordinary UHV HTV silicone rubber materials. The water absorption rate and boiling time data are shown in Table 1.
[0055] Example 4:
[0056] The HTV silicone rubber material in Example 4 of this invention is composed of the following raw materials by mass fraction: 100 parts of compounded methyl vinyl silicone rubber, 30 parts of reinforcing agent, 80 parts of aluminum hydroxide, and 18 parts of other additives, including 3 parts of silane coupling agent, 6 parts of colorant, 2 parts of vulcanizing agent, and 6 parts of silicone oil. The aluminum hydroxide is only type B with surface silanization treatment and a particle size D50 of 4 μm; other components are the same as in Example 1. Performance tests and accelerated aging tests were conducted on the prepared samples, and the results were compared with those of commercially available ordinary ultra-high voltage HTV silicone rubber material. The water absorption rate and boiling time data are shown in Table 1.
[0057] Comparative Example 1:
[0058] The HTV silicone rubber material in Comparative Example 1 of this invention is composed of the following raw materials by mass fraction: 100 parts of compounded methyl vinyl silicone rubber, 30 parts of reinforcing agent, 60 parts of compounded aluminum hydroxide, and 18 parts of other additives, including 3 parts of silane coupling agent, 6 parts of colorant, 2 parts of vulcanizing agent, and 6 parts of silicone oil. The aluminum hydroxide is composed of untreated type A with a particle size D50 of 1 μm and surface-silanized type B with a particle size D50 of 4 μm; the weight ratio of aluminum hydroxide A to aluminum hydroxide B is 6:1. Other properties are the same as in Example 1. Performance tests and accelerated aging tests were conducted on the prepared samples, and the results were compared with those of commercially available ordinary ultra-high voltage HTV silicone rubber materials. The water absorption rate was lower, but other properties did not meet product requirements, i.e., it failed the tracking resistance test.
[0059] Comparative Example 2:
[0060] The HTV silicone rubber material in Comparative Example 2 of this invention is composed of the following raw materials by mass fraction: 100 parts of compounded methyl vinyl silicone rubber, 30 parts of reinforcing agent, 100 parts of compounded aluminum hydroxide, and 18 parts of other additives, including 3 parts of silane coupling agent, 6 parts of colorant, 2 parts of vulcanizing agent, and 6 parts of silicone oil. The aluminum hydroxide is composed of type A (untreated, particle size D50 of 1 μm) and type B (surface-silanized, particle size D50 of 4 μm); the weight ratio of aluminum hydroxide A to aluminum hydroxide B is 6:1. Other aspects are the same as in Example 1. Performance tests and accelerated aging tests were conducted on the prepared samples, and the results were compared with those of commercially available ordinary ultra-high voltage HTV silicone rubber material. The water absorption rate and boiling time data are shown in Table 1.
[0061] Table 1
[0062]
[0063]
[0064] contrast Figure 1a and Figure 1b As shown in Table 1, the HTV silicone rubber materials, after being boiled in water for 28 days, exhibited a water absorption rate of 1.47% for commercially available products after 500 hours. In contrast, the HTV silicone rubber materials of Examples 1-3 of this invention had water absorption rates of 0.61%, 0.62%, and 0.74% respectively after 500 hours. Not only after 28 days of boiling, but also after 0 days (no aging), 4 days, 8 days, and 20 days of boiling, the HTV silicone rubber materials of Examples 1-3 of this invention still demonstrated superior water absorption resistance compared to commercially available ordinary ultra-high voltage HTV silicone rubber materials.
[0065] The water absorption test showed that the HTV silicone rubber samples prepared according to Examples 1-3 of the present invention had a water absorption rate that was nearly 60% lower than that of commercially available traditional formulations. The lower water absorption rate can inhibit the aging of silicone rubber materials in a humid and hot environment, that is, inhibit the occurrence of aging phenomena such as main chain hydrolysis and polarization heating.
[0066] Experimental Example 1:
[0067] By observing the surface morphology of the HTV silicone rubber material of Example 1 of the present invention and the commercially available ultra-high voltage HTV silicone rubber material using SEM (scanning electron microscopy), it can be found that when the HTV silicone rubber material has not been aged, the HTV silicone rubber material of Example 1 of the present invention is as follows: Figure 2a As shown, commercially available HTV silicone rubber material for ultra-high voltage applications includes... Figure 3a As shown, both have relatively smooth surface morphology, without pores or cracks, and no filler leakage was observed; after artificial accelerated aging, the HTV silicone rubber material of Example 1 of this invention is as follows: Figure 2b As shown, although there are a few large voids on the surface, the overall surface still maintains a certain degree of flatness; commercially available HTV silicone rubber material for ultra-high voltage applications, such as... Figure 3b As shown, its surface has lost its smoothness, the aging phenomenon is obvious, and a large number of small-diameter fillers have precipitated on the surface. The main reason is that the HTV silicone rubber of Example 1 of this invention uses two types of ATH with different particle sizes. Under the same mass fraction, the large-diameter ATH with surface silanization has a smaller specific surface area than the small-diameter ATH, which can effectively reduce the microscopic interface between silicone and inorganic fillers. Surface silanization treatment can effectively improve the dispersion characteristics of large-diameter fillers and improve the interface strength, enhance the binding adhesive content around inorganic particles, inhibit the precipitation of fillers after aging, and ensure that the material still has a good surface structure after aging, effectively inhibiting moisture intrusion. Among them, the artificial accelerated aging is to wipe the surface of the test sample clean with anhydrous ethanol and non-woven cloth, and then put it into a constant temperature digital display water bath containing 0.1% (by weight) NaCl deionized water and heat it at a constant temperature for 100h. The temperature of the constant temperature digital display water bath is set at 100℃. The conductivity of the aqueous solution should be controlled at (1750±80) μS / cm. If there are differences in water temperature, the conductivity should be corrected according to Chapter 7 of GB / T4585-2004. After boiling, the sample is allowed to cool and should be kept in water until the test is conducted.
[0068] Experimental Example 2:
[0069] The mechanical properties of the HTV silicone rubber material of Embodiment 1 of this invention and commercially available UHV HTV silicone rubber material were evaluated. Tensile strength and elongation at break are important indicators for evaluating the mechanical properties of composite insulator skirts and sheath materials. Silicone rubber materials with substandard mechanical properties are prone to damage during grid operation due to mechanical stress of the line and external forces such as bird pecks, thereby increasing the risk of exposure of the internal interface of the insulator. Therefore, it is necessary to test the change of mechanical strength of the insulator silicone rubber material with accelerated aging.
[0070] like Figure 4 and Figure 5 As shown, a comparison of the tensile strength and elongation at break of the HTV silicone rubber material in Example 1 of this invention and the commercially available HTV silicone rubber material with boiling time data reveals that the HTV silicone rubber material in Example 1 of this invention possesses better mechanical properties than traditional commercially available HTV silicone rubber materials, and its mechanical properties remain excellent even with prolonged boiling and damp heat aging time. The main reason for this is the lower ATH content in the HTV silicone rubber material of this formulation, which avoids the consequence of uneven dispersion and decreased mechanical strength caused by excessive ATH.
[0071] Experimental Example 3:
[0072] The dielectric loss performance of the HTV silicone rubber material of Example 1 of this invention and a commercially available ultra-high voltage HTV silicone rubber material was evaluated. Under the action of a strong electric field, heat is generated inside the composite material due to dielectric loss. The dielectric loss P at this time can be expressed as P = 2πfU²Ctanδ. In the formula, f is the frequency of the voltage, C is the capacitance of the composite material, U is the effective value of the voltage applied to the sample, and tanδ represents the dielectric loss tangent of the composite material. It can be seen that the dielectric loss tangent has an important influence on dielectric loss heating. Figure 6 As shown, the dielectric loss tangent of the HTV silicone rubber material in Example 1 of this invention is lower than that of commercially available ordinary HTV silicone rubber material for ultra-high voltage external insulation, and its increase with water boiling and damp heat aging is relatively slow. The main reason is that the amount of ATH in the HTV silicone rubber material of Example 1 of this invention is less than that in traditional formulations. ATH has a higher dielectric constant and dielectric loss than silicone rubber, and its presence in the composite material will lead to a deterioration in the dielectric properties of the composite material.
[0073] Experiment Example 4:
[0074] The electro-erosion resistance of the HTV silicone rubber material of Example 1 of this invention and commercially available ultra-high voltage HTV silicone rubber material were evaluated. The HTV silicone rubber material of Example 1 of this invention significantly reduces the amount of ATH (Al₂O₃) used. The biggest potential negative impact of this measure is a decrease in electro-erosion resistance. However, by adjusting the ratio of Si, Al, and Fe oxides, the HTV silicone rubber material of Example 1 of this invention can effectively pass the tracking resistance level 4.5 test. Specifically, as shown below... Figure 7 As shown, the commercially available ultra-high voltage HTV silicone rubber material, after testing for tracking resistance level 4.5, is as follows: Figure 8 As shown, the HTV silicone rubber material of Embodiment 1 of the present invention has the same resistance to electro-erosion as commercially available HTV silicone rubber materials for ultra-high voltage applications, and even better resistance. The principle of adjusting the ratio of Si, Al, and Fe oxides in the HTV silicone rubber material of Embodiment 1 of the present invention is as follows: by promoting the formation of a chemically stable mullite ceramic layer at high temperatures by SiO2, Al2O3, and Fe2O3 oxides, the heat from the electric arc is blocked, ensuring that the internal material of the silicone rubber is not further damaged.
[0075] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, several equivalent substitutions or obvious modifications can be made without departing from the concept of the present invention, and all such modifications, achieving the same performance or purpose, should be considered within the scope of protection of the present invention.
Claims
1. An HTV silicone rubber material, characterized in that, By weight, it includes the following components: 100 parts of methyl vinyl silicone rubber; 25-40 parts of reinforcing agent; 70-90 parts of aluminum hydroxide; Other additives: 11-23 parts; The aluminum hydroxide is selected from aluminum hydroxide A with untreated surface and particle size D50 of 1~2μm and aluminum hydroxide B with surface silanization treatment and particle size D50 of 3~5μm, and the weight ratio of aluminum hydroxide A to aluminum hydroxide B is 5:1~8:
1. The prepared HTV silicone rubber material is used to prevent abnormal heating and deterioration of UHV composite insulators under high humidity and heat conditions.
2. The HTV silicone rubber material as described in claim 1, characterized in that, The methyl vinyl silicone rubber is composed of two base rubbers with vinyl contents of 0.04% and 0.22%, and the vinyl content of the compounded methyl vinyl silicone rubber reaches 0.12~0.15%.
3. The HTV silicone rubber material as described in claim 1, characterized in that, The reinforcing agent is selected from one or more of nano-silica and vinyl MQ silicone resin.
4. The HTV silicone rubber material as described in claim 1, characterized in that, By weight, the other additives include 2-4 parts coupling agent, 4-8 parts colorant, 1-3 parts vulcanizing agent and 4-8 parts silicone oil.
5. The HTV silicone rubber material as described in claim 4, characterized in that, The coupling agent is selected from silane coupling agents containing amino, methoxy, and vinyl functional groups; the colorant is selected from silica gel with an iron oxide content of more than 70% by mass; the vulcanizing agent is selected from bis(2,5-dimethyl)sulfide; and the silicone oil is selected from a compound of hydroxyl silicone oil and hydrogen-containing silicone oil.
6. The application of the HTV silicone rubber material as described in any one of claims 1 to 5 in ultra-high voltage composite insulators under high humidity and heat conditions.