Silicone rubber composition as well as preparation method and application thereof in insulating sleeve

Abstract

The invention discloses a silicone rubber composition as well as a preparation method and application thereof in an insulating sleeve, and belongs to the technical field of silicone rubber materials. The silicone rubber composition comprises the following raw materials in parts by weight: 35-55 parts of vinyl silicone rubber, 20-35 parts of a reinforcing agent, 7-10 parts of polyimide, 8-18 parts of a modifier, 1-2 parts of a vulcanizing agent and 4-9 parts of a cross-linking agent. 0-23 parts of an auxiliary agent; the modifier comprises graphene oxide, boron nitride, barium titanate, an antioxidant, a dispersing agent and a solvent. The silicon rubber is modified by compounding the modifier composed of the graphene and the positive temperature coefficient material and the polyimide, so that the silicon rubber is endowed with a spontaneous heating characteristic on the basis of not degrading the mechanical strength and the insulating property, a good heat preservation effect can be achieved, and the application requirements of insulating sleeves in cold regions are met.

Description

Technical Field

[0001] The present application relates to the technical field of silicone rubber materials, in particular to a silicone rubber composition, a preparation method thereof, and an application in an insulating sleeve. Background Art

[0002] With the rapid development of power engineering and industrial technologies, wire and cable systems are increasingly widely used in infrastructure. At low temperatures, the resistance of the conductor will increase, resulting in a decrease in power transmission efficiency. At the same time, the cable material may harden and become brittle, making it prone to breakage or damage. In cold regions, the anti-freezing and heat preservation problems of wires and cables have become key problems that need to be solved urgently.

[0003] Insulating sleeves can effectively isolate wires and cables from the outside, prevent current leakage, and ensure the safe operation of the electrical system. However, ordinary insulating sleeves mostly use thermal insulation materials such as polyurethane foam, polyethylene foam, glass wool, and asbestos, which do not have good waterproof performance, are prone to water penetration, have poor heat preservation effects, and do not have a self-heating function. They cannot heat wires and cables in low-temperature environments, affecting their normal operation and even causing damage, and require regular inspection and maintenance, resulting in high operation and maintenance costs.

[0004] Therefore, it is particularly important to develop a silicone rubber composition that can self-heat and can be used in insulating sleeves. Summary of the Invention

[0005] Based on this, the main purpose of the present application is to provide a silicone rubber composition that can self-heat and can be used in insulating sleeves to meet the application requirements of insulating sleeves in cold regions.

[0006] In the first aspect of the present application, a silicone rubber composition is provided, which includes the following raw materials by weight parts:

[0007] 35-55 parts of vinyl silicone rubber, 20-35 parts of reinforcing agent, 7-10 parts of polyimide, 8-18 parts of modifier, 1-2 parts of vulcanizing agent, 4-9 parts of cross-linking agent; 0-23 parts of auxiliary agent;

[0008] The modifier includes: graphene oxide, boron nitride, barium titanate, antioxidant, dispersant, and solvent;

[0009] The mass ratio of graphene oxide, boron nitride, barium titanate, antioxidant, dispersant, and solvent is 44:20-40:5-15:1-5:2-8:20-50.

[0010] In some embodiments, the solid content of the modifier is 50wt%-80wt%.

[0011] In some embodiments, the silicone rubber composition satisfies one or more of the following conditions:

[0012] (1) The vinyl silicone rubber includes methyl vinyl silicone rubber;

[0013] (2) The reinforcing agent includes silica;

[0014] (3) The vulcanizing agent includes 2,4-dichlorobenzoyl peroxide;

[0015] (4) The crosslinking agent includes methyl hydrogen silicone oil.

[0016] In some embodiments, the auxiliary agent includes at least one of water, coupling agent, and release agent;

[0017] The solvent includes at least one of dimethylacetamide and water.

[0018] In some embodiments, the silicone rubber composition satisfies one or more of the following conditions:

[0019] (1) The amount of the water is 5-12 parts;

[0020] (2) The amount of the coupling agent is 3-8 parts;

[0021] (3) The amount of the release agent is 1-3 parts;

[0022] (4) The coupling agent includes at least one of vinyl silazane, γ-glycidoxypropyltrimethoxysilane, hexamethyldisilazane, and vinyl tris(2-methoxyethoxy)silane;

[0023] (5) The release agent includes stearic acid;

[0024] (6) The silica includes precipitated silica and / or fumed silica.

[0025] In the second aspect of the present application, there is provided a method for preparing the silicone rubber composition described in the first aspect, including the following steps:

[0026] First mix the raw materials other than the reinforcing agent and the vulcanizing agent, and then perform a second mixing with the reinforcing agent to prepare a mixed rubber compound;

[0027] Perform a third mixing of the mixed rubber compound with the vulcanizing agent to prepare the silicone rubber composition.

[0028] In some embodiments, the preparation method satisfies one or more of the following conditions:

[0029] (1) The conditions for the first mixing include: kneading at 60°C - 80°C for 0.5 h - 2 h;

[0030] (2) The conditions for the second mixing include: kneading at 160°C - 180°C for 1 h - 3 h;

[0031] (3) The third mixing includes open mill mixing and / or internal mixer mixing.

[0032] In the third aspect of the present application, there is provided an application of the silicone rubber composition described in the first aspect in an insulating sleeve.

[0033] In the fourth aspect of the present application, there is provided an insulating sleeve, the raw materials of which include the silicone rubber composition described in the first aspect.

[0034] In the fifth aspect of the present application, there is provided a method for preparing the insulating sleeve described in the fourth aspect, including the following steps:

[0035] Vulcanizing and molding the silicone rubber composition to prepare the insulating sleeve.

[0036] The beneficial effects of the present application:

[0037] 1. The present application uses a modifier composed of graphene and a positive temperature coefficient material in combination with polyimide to modify silicone rubber, which can endow silicone rubber with self-heating characteristics without deteriorating mechanical strength and insulation performance, achieving a good heat preservation effect and meeting the application requirements of insulating sleeves in cold regions.

[0038] 2. The silicone rubber composition of the present application is used in an insulating sleeve. When the wire and cable operate at low temperatures, the insulating sleeve can "automatically heat up", reducing energy loss, having a good heat preservation effect, preventing the pipeline from freezing, and having excellent waterproof performance. Moreover, it has a simple structure, convenient installation, and low maintenance cost. Specific Embodiments

[0039] To make the objectives, technical solutions, and advantages of the present application clearer and the understanding of the disclosed content of the present application more thorough and comprehensive, the technical solutions of the present application will be clearly and completely described below in conjunction with specific embodiments of the present application. The described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments.

[0040] The following is a detailed description of the implementation of the present application. This embodiment is implemented on the premise of the technical solution of the present application, and detailed implementation methods and specific operation processes are given, but the protection scope of the present application is not limited to the following embodiments.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs. The terms used in the specification of this application herein are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0042] Terms

[0043] Unless otherwise specified or there is a contradiction, the terms or phrases used in this article have the following meanings:

[0044] In this application, when it comes to "multiple", "multiple types", etc., without special limitations, it means greater than 2 or equal to 2 in quantity. For example, "one or more types", "at least one type" means one type or greater than or equal to two types.

[0045] In this application, "further", "especially", etc. are used for descriptive purposes, indicating differences in content, but should not be understood as limiting the scope of protection of this application.

[0046] In this application, among the technical features described in an open-ended manner, it includes a closed technical solution composed of the listed features, and also includes an open technical solution containing the listed features.

[0047] In this application, when it comes to a numerical interval (that is, a numerical range), without special instructions, the distribution of the optional numerical values within this numerical interval is regarded as continuous, and includes the two numerical endpoints of this numerical interval (that is, the minimum value and the maximum value), as well as each numerical value between these two numerical endpoints. Without special instructions, when the numerical interval only refers to the integers within this numerical interval, it includes the two endpoint integers of this numerical range, as well as each integer between the two endpoints, which is equivalent to directly listing each integer. When providing multiple numerical ranges to describe features or characteristics, these numerical ranges can be combined. In other words, unless otherwise specified, the numerical ranges disclosed in this article should be understood to include any and all sub-ranges subsumed therein. The "numerical value" in this numerical interval can be any quantitative value, such as a number, a percentage, a ratio, etc. The "numerical interval" allows for a broad inclusion of numerical interval types such as a percentage interval, a ratio interval, a ratio value interval, etc.

[0048] In this application, without special limitations, the temperature parameter allows both for isothermal treatment and for variation within a certain temperature interval. It should be understood that the so-called isothermal treatment allows the temperature to fluctuate within the accuracy range controlled by the instrument. Fluctuations within ranges such as ±5°C, ±4°C, ±3°C, ±2°C, and ±1°C are allowed.

[0049] The term "and / or" used in this article includes any and all combinations of one or more of the related listed items.

[0050] In this application, for the temperature parameter, without special limitations, it allows both for isothermal treatment and for treatment within a certain temperature interval. The so-called isothermal treatment allows the temperature to fluctuate within the accuracy range controlled by the instrument.

[0051] In the first aspect of this application, there is provided a silicone rubber composition, by weight parts, comprising the following raw materials:

[0052] 35 - 55 parts of vinyl silicone rubber, 20 - 35 parts of reinforcing agent, 7 - 10 parts of polyimide, 8 - 18 parts of modifier, 1 - 2 parts of vulcanizing agent, 4 - 9 parts of crosslinking agent; 0 - 23 parts of auxiliary agent;

[0053] The modifier includes: graphene oxide, boron nitride, barium titanate, antioxidant, dispersant and solvent;

[0054] The mass ratio of graphene oxide, boron nitride, barium titanate, antioxidant, dispersant and solvent is 44:20 - 40:5 - 15:1 - 5:2 - 8:20 - 50.

[0055] Silicone rubber has excellent electrical insulation performance, with a volume resistivity as high as 4×10 14 Ω·cm, and excellent performance in dielectric loss, breakdown voltage, arc resistance, corona resistance, volume resistivity and surface resistivity, etc.; The main molecular chain is composed of alternating silicon atoms and oxygen atoms (-Si-O-Si-), with extremely high thermal stability and can be used for a long time in the temperature range of -90°C to +300°C; There are no double bonds in the main chain structure, with excellent weather resistance and aging resistance, and the service life in the natural environment can reach several decades; It has good waterproof performance and can effectively prevent moisture from penetrating. The above characteristics of silicone rubber make it an ideal material for preparing insulating sleeves. However, silicone rubber does not have the self-heating characteristic and cannot effectively protect the pipeline at low temperatures.

[0056] Positive temperature coefficient (PTC) materials are a type of thermosensitive materials whose resistivity increases sharply with the increase of temperature and can achieve self-regulation during the self-heating process. When the temperature of the PTC material rises, its resistance value also increases, which leads to a decrease in the current passing through the material, thereby reducing the generated heat. On the contrary, when the temperature decreases, the resistance value decreases, the current increases, and the generated heat increases. This mechanism enables the PTC material to maintain its temperature at a relatively stable level to a certain extent.

[0057] As a positive temperature coefficient material, graphene oxide generates heat due to resistance when current passes through, achieving the function of self-heating. Boron nitride has excellent thermal conductivity, insulation performance and low thermal expansion coefficient, which can improve the insulation performance and thermal conductivity of the material and adjust the thermal expansion coefficient; Polyimide has low thermal conductivity, high mechanical strength and good insulation, which can reduce heat loss and play a heat preservation role.

[0058] This application uses a modifier composed of graphene and boron nitride in combination with polyimide to modify silicone rubber. Without degrading the mechanical strength and insulation performance, it can endow silicone rubber with self-heating characteristics, achieving a good heat preservation effect and meeting the application requirements of insulating sleeves in cold regions.

[0059] In a specific example, the dispersant includes at least one of polyvinylpyrrolidone, polyacrylate dispersants, cellulose dispersants, sodium dodecylbenzenesulfonate, and sodium dodecylsulfonate.

[0060] In a specific example, the antioxidant includes at least one of antioxidant 1010, antioxidant 1035, and antioxidant 1076.

[0061] In a specific example, the solvent includes at least one of dimethylacetamide and water; a mixed solvent of dimethylacetamide and water is optional; further optionally, the mass ratio of dimethylacetamide to water is 8:20 - 40, such as 8:20, 8:25, 8:30, 8:35, 8:40, etc.

[0062] In a specific example, the preparation method of the modifier includes the following steps:

[0063] Mix and disperse the raw materials except water, grind them to a fineness ≤ 20μm, and add water to dilute to a viscosity of 500mPa.s - 1500mPa.s.

[0064] In a specific example, the grinding time is 2h - 4h.

[0065] In a specific example, after adding water to dilute to a viscosity of 500mPa.s - 1500mPa.s, a filtration step is further included. Optionally, a 400 - 600 mesh filter screen is used for filtration.

[0066] In a specific example, the addition amount of the modifier can specifically be 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, etc.

[0067] In a specific example, the solid content of the modifier is 50wt% - 80wt%, such as 50wt%, 55wt%, 60wt%, 65wt%, 70wt%, 75wt%, 80wt%, etc.

[0068] In a specific example, the viscosity of the modifier is 500mPa.s - 1500mPa.s, such as 500mPa.s, 700mPa.s, 900mPa.s, 1000mPa.s, 1200mPa.s, 1500mPa.s, etc.

[0069] In this application, vinyl silicone rubber is used as the matrix material, and there are no special requirements for its specific type and parameters. The addition amount can specifically be 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, etc.

[0070] In a specific example, the vinyl silicone rubber includes methyl vinyl silicone rubber.

[0071] In a specific example, the vinyl content of the methyl vinyl silicone rubber is 0.1% - 0.3%, preferably 0.16% - 0.22%.

[0072] In a specific example, the addition amount of the reinforcing agent can specifically be 20 parts, 25 parts, 30 parts, 35 parts, etc.

[0073] In a specific example, the reinforcing agent includes silica.

[0074] In a specific example, the silica includes precipitated silica and / or fumed silica; preferably precipitated silica.

[0075] In a specific example, the addition amount of the polyimide can specifically be 7 parts, 8 parts, 9 parts, 10 parts, etc.

[0076] In a specific example, the addition amount of the vulcanizing agent can specifically be 1 part, 1.2 parts, 1.4 parts, 1.6 parts, 1.8 parts, etc.

[0077] In a specific example, the vulcanizing agent includes 2,4-dichlorobenzoyl peroxide.

[0078] In a specific example, the addition amount of the crosslinking agent can specifically be 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, etc.

[0079] In a specific example, the crosslinking agent includes methyl hydrogen silicone oil.

[0080] In a specific example, the auxiliary agent includes at least one of water, coupling agent, and mold release agent.

[0081] In a specific example, the amount of water used is 5 - 12 parts, such as 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, etc.

[0082] In a specific example, the amount of the coupling agent used is 3 - 8 parts, such as 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, etc.

[0083] In a specific example, the coupling agent includes at least one of vinyl silazane, γ-glycidoxypropyltrimethoxysilane, hexamethyldisilazane, and vinyltris(2-methoxyethoxy)silane.

[0084] In a specific example, the dosage of the mold release agent is 1 - 3 parts, such as 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, etc.

[0085] In a specific example, the mold release agent includes stearic acid.

[0086] In a specific example, by weight parts, the silicone rubber composition includes the following raw materials:

[0087] 35 - 55 parts of vinyl silicone rubber, 20 - 35 parts of reinforcing agent, 7 - 10 parts of polyimide, 8 - 18 parts of modifier, 1 - 2 parts of vulcanizing agent, 4 - 9 parts of crosslinking agent, 5 - 12 parts of water, 3 - 8 parts of coupling agent, and 1 - 3 parts of mold release agent.

[0088] In a second aspect of the present application, there is provided a preparation method of the silicone rubber composition described in the first aspect, including the following steps:

[0089] Perform a first mixing on the raw materials other than the reinforcing agent and the vulcanizing agent, and then perform a second mixing with the reinforcing agent to prepare a mixed rubber compound;

[0090] Perform a third mixing on the mixed rubber compound with the vulcanizing agent to prepare the silicone rubber composition.

[0091] In a specific example, the conditions of the first mixing include: kneading at 60°C - 80°C for 0.5 h - 2 h; wherein, the mixing temperature can specifically be 60°C, 65°C, 70°C, 75°C, 80°C, etc.; the mixing time can be 0.5 h, 1 h, 1.5 h, 2 h, etc.

[0092] In a specific example, the conditions of the second mixing include: kneading at 160°C - 180°C for 1 h - 3 h; wherein, the mixing temperature can specifically be 160°C, 165°C, 170°C, 175°C, 180°C, etc.; the mixing time can be 1 h, 1.5 h, 2 h, 2.5 h, 3 h, etc.

[0093] In a specific example, the third mixing includes open mill mixing and / or internal mixer mixing; preferably open mill mixing.

[0094] In a specific example, it further includes the steps of vacuumizing and / or pressure filtering the mixed rubber compound.

[0095] In a specific example, the conditions of the vacuumizing include: vacuumizing at 150°C - 180°C for 1 h - 3 h.

[0096] The third aspect of the present application provides the use of the silicone rubber composition described in the first aspect in an insulating sleeve.

[0097] A fourth aspect of the present application provides an insulating sleeve, the raw materials of which include the silicone rubber composition described in the first aspect.

[0098] The fifth aspect of the present application provides a method for preparing the insulating sleeve according to the fourth aspect, comprising the following steps:

[0099] The insulating sleeve is prepared by vulcanizing and molding the silicone rubber composition.

[0100] Unless otherwise specified, the raw materials used in the following experiments can be purchased from the market.

[0101] The exemplary descriptions of the raw materials used in the examples and comparative examples are as follows:

[0102] Methyl vinyl silicone rubber: model 110-2, vinyl content 0.16%, purchased from Dongjue Silicone;

[0103] White carbon black: Model A200, purchased from Evonik Degussa;

[0104] Polyimide: Model 308, purchased from DuPont;

[0105] Graphene oxide: purchased from Henan Liugong Graphite Co., Ltd.

[0106] Boron nitride: model BNH01, purchased from Beasley;

[0107] Barium titanate: purchased from Wuhan Jiyesheng Chemical Co., Ltd.;

[0108] Antioxidant: 1035, purchased from BASF;

[0109] Dispersant: sodium polyacrylate, purchased from Dongguan Shuangling New Materials Co., Ltd.;

[0110] Methyl hydrogen silicone oil: Model AK350, purchased from Wacker Chemical (China) Co., Ltd.;

[0111] Curing agent: 2,4-dichlorobenzoyl peroxide (DCBP), commercially available;

[0112] Coupling agent: vinyl silazane, commercially available;

[0113] Release agent: stearic acid, commercially available;

[0114] Other raw materials are commercially available.

[0115] The following are specific embodiments.

[0116] Preparation Example 1

[0117] Preparation of Modifier

[0118] Graphene oxide, boron nitride, barium titanate, antioxidant (1035), dispersant (sodium polyacrylate) and solvent (dimethylacetamide) were mixed at a mass ratio of 44:32:9.5:2.5:4:8, dispersed by high-speed stirring, and then ground with a three-roll mill for 2 - 4 hours until the fineness was ≤ 20 μm. 30 parts of solvent (water) was added with low-speed stirring to adjust the viscosity to 1000 mPa·s, and impurities were removed by filtration (500 mesh), followed by vacuum degassing to obtain the modifier.

[0119] Examples 1 - 6

[0120] Preparation of Silicone Rubber Composition:

[0121] The formulations of the silicone rubber compositions of Examples 1 - 6 are shown in Table 1:

[0122] Table 1 Formulations of Silicone Rubber Compositions of Examples 1 - 6

[0123]

[0124] The preparation method is as follows:

[0125] 1) Raw materials other than the reinforcing agent and vulcanizing agent were added together to a kneader, kneaded at 70 °C for 1 h under constant temperature; the temperature was raised to 165 °C, and the reinforcing agent was added in 3 portions, and kneaded under constant temperature for 2 h to obtain a mixed rubber compound;

[0126] 2) The mixed slurry was evacuated at 160 - 170 °C for 1 h and filtered by pressure filtration to obtain the evacuated mixed rubber compound;

[0127] 3) The vulcanizing agent was added to the evacuated mixed rubber compound, and kneaded and mixed on an open mill to obtain the silicone rubber composition.

[0128] The prepared silicone rubber composition was extruded and vulcanized into a specific shape according to the test requirements for performance testing.

[0129] Comparative Example 1

[0130] Compared with Example 5, the difference was only that the modifier (graphene PTC insulating paste) was not added, and the others were the same as Example 5.

[0131] Comparative Example 2

[0132] Compared with Example 6, the difference was only that the modifier (graphene PTC insulating paste) was not added, and the others were the same as Example 6.

[0133] Test Example

[0134] After the silicone rubber compositions of the examples and comparative examples are extruded by an extruder and vulcanized into a specific shape according to the test requirements, the following performance tests are carried out:

[0135] 1. Hardness: Shore A, and the test standard is "GB / T531.1 - 2008";

[0136] 2. Density: Density after vulcanization, and the test standard is "GB / T533 - 1991";

[0137] 3. Tensile strength, elongation at break, and tear strength: The test standard is "GB / T528 - 2009";

[0138] 4. Dielectric breakdown strength: The test standard is "ASTM - D - 4325";

[0139] 5. Heating rate test: After covering the bare wire with an insulating sleeve, use an infrared thermal imager to test the temperature change rate of the material. Preheat the instrument for 15 - 30 minutes, calibrate the instrument using a blackbody radiation source to ensure the detector is stable. Set the emissivity, adjust the test distance and angle from the insulating sleeve, and test the heating rate.

[0140] The results are shown in Table 2.

[0141] Table 2 Summary of the performance of the examples and comparative examples

[0142]

[0143] As can be seen from Table 2, Examples 1 - 6 have good mechanical strength and insulation performance, and the heating rate > 1.5 °C / min, showing good self - heating performance during heating.

[0144] By comparing Example 5 and Comparative Example 1, and Example 6 and Comparative Example 2, it can be seen that the addition of the modifier (graphene PTC insulating paste) does not lead to the deterioration of mechanical strength and insulation performance. On the basis of maintaining mechanical strength and insulation performance, it greatly improves the self - heating performance during heating.

[0145] The technical features of the above - described examples can be combined arbitrarily. For the sake of brevity in description, not all possible combinations of the technical features in the above - described examples are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0146] The above-described embodiments merely represent several implementation manners of the present application. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all fall within the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims.

Claims

1. A silicone rubber composition, characterized in that, By weight parts, it comprises the following raw materials: 35 - 55 parts of vinyl silicone rubber, 20 - 35 parts of reinforcing agent, 7 - 10 parts of polyimide, 8 - 18 parts of modifier, 1 - 2 parts of vulcanizing agent, 4 - 9 parts of crosslinking agent; 0 - 23 parts of auxiliary agent; The modifier comprises: graphene oxide, boron nitride, barium titanate, antioxidant, dispersant and solvent; The mass ratio of graphene oxide, boron nitride, barium titanate, antioxidant, dispersant and solvent is 44:20 - 40:5 - 15:1 - 5:2 - 8:20 - 50.

2. The silicone rubber composition according to claim 1, characterized in that, The solid content of the modifier is 50wt% - 80wt%.

3. The silicone rubber composition according to claim 1 or 2, characterized in that, Meet one or more of the following conditions: (1) The vinyl silicone rubber comprises methyl vinyl silicone rubber; (2) The reinforcing agent comprises silica; (3) The vulcanizing agent comprises 2,4 - dichlorobenzoyl peroxide; (4) The crosslinking agent comprises methyl hydrogen silicone oil.

4. The silicone rubber composition according to claim 1 or 2, characterized in that, The auxiliary agent comprises at least one of water, coupling agent and release agent; The solvent comprises at least one of dimethylacetamide and water.

5. The silicone rubber composition according to claim 4, wherein Meet one or more of the following conditions: (1) The dosage of the water is 5 - 12 parts; (2) The dosage of the coupling agent is 3 - 8 parts; (3) The dosage of the release agent is 1 - 3 parts; (4) The coupling agent comprises at least one of vinyl silazane, γ - glycidoxypropyltrimethoxysilane, hexamethyldisilazane and vinyl tris(2 - methoxyethoxy)silane; (5) The release agent comprises stearic acid; (6) The silica comprises precipitated silica and / or fumed silica.

6. The preparation method of the silicone rubber composition according to any one of claims 1-5, characterized in that, It comprises the following steps: Mix the raw materials other than the reinforcing agent and the vulcanizing agent for the first time, and then mix with the reinforcing agent for the second time to prepare a mixed rubber compound; Mix the mixed rubber compound with the vulcanizing agent for the third time to prepare the silicone rubber composition.

7. The preparation method according to claim 6, wherein Meet one or more of the following conditions: (1) The conditions for the first mixing include: kneading at 60°C - 80°C for 0.5h - 2h; (2) The conditions for the second mixing include: kneading at 160°C - 180°C for 1h - 3h; (3) The third mixing includes open mill mixing and / or internal mixer mixing.

8. The application of the silicone rubber composition according to any one of claims 1 - 5 in an insulating sleeve.

9. An insulating sleeve, characterized in that, The raw materials comprise the silicone rubber composition according to any one of claims 1 - 5.

10. The manufacturing method of the insulating sleeve according to claim 9, characterized in that, It comprises the following steps: Vulcanize and mold the silicone rubber composition to prepare the insulating sleeve.

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