Self-lubricating silicone rubber and method for producing the same

Abstract

This invention discloses a self-lubricating silicone rubber and its preparation method, belonging to the field of polymer materials technology. The self-lubricating silicone rubber, by mass parts, comprises: 100 parts methyl vinyl silicone rubber, 5-10 parts hydroxyl fluorosilicone oil, 25-60 parts silica, 1-5 parts vinyl fluorosilicone oil, 0.5-1.5 parts treatment agent, 2-5 parts heat resistant agent, 4-6 parts self-lubricating additive, 0.02-0.05 parts low-pressure modifier, and 1-2 parts vulcanizing agent. The self-lubricating additive is newly synthesized; its addition in small amounts enables the rubber compound to achieve self-lubricating function with minimal impact on the mechanical properties of the compound, effectively avoiding excessive oil seepage. The low-pressure modifier is also newly synthesized; its addition in small amounts significantly improves the compression set performance of the rubber compound. Combined with components such as hydroxyl fluorosilicone oil and vinyl fluorosilicone oil, it effectively improves the acid and oil resistance of the rubber compound. Furthermore, the preparation process is simple and can effectively improve production efficiency.

Description

Technical Field

[0001] This invention relates to a silicone rubber and its preparation method, specifically to a self-lubricating silicone rubber and its preparation method, belonging to the field of polymer materials technology. Background Technology

[0002] Silicone rubber is a high-molecular polymer with (-Si-O-)n as the main chain and organic side groups. It possesses excellent heat resistance, low-temperature resistance, weather resistance, UV resistance, and biological properties. The high flexibility of the silicone rubber molecular chain and the weak intermolecular forces result in soft and elastic silicone rubber after vulcanization. Furthermore, because it does not contain softeners, plasticizers, or antioxidants, it does not cause environmental pollution. Therefore, it is widely used in various fields such as power batteries, connectors, and charging equipment for new energy vehicles.

[0003] Self-lubricating silicone rubber, due to the oil droplets that seep out from its cured surface, effectively reduces surface friction and achieves lubrication. Therefore, it is widely used in components such as wire harnesses, cables, and connectors that require insertion, removal, and sealing. With the development of new energy vehicle technology, battery pack energy density has increased, charging voltage has risen, transmission current has increased, and the operating temperature of components has risen. The material operating environment has become more complex. At high temperatures, the material may come into contact with acidic substances, lubricating oils, transmission fluids, gear oils, and other substances, placing higher and more demanding requirements on the performance of self-lubricating silicone rubber used as a sealing material.

[0004] Although the prior art CN110922763A discloses a high-temperature resistant, low-compression-set self-oil-extracting compound and its preparation method, the preparation process of this scheme is complex. The mixing process requires multiple heating and cooling cycles, and the self-oil-extracting additive also needs to be added in multiple stages, which is time-consuming. Moreover, the amount of the self-oil-extracting additive, methylphenyl silicone oil, added is relatively large, at 5-10 parts. This silicone oil acts as a plasticizer in the compound, affecting the product's compression set and long-term heat aging performance. It also leads to low Mooney viscosity in the compound, resulting in poor processing performance in actual use. Furthermore, this technology does not mention how to improve acid and oil resistance. CN115558300B discloses a compounded silicone rubber. The invention relates to a rubber compound, its preparation method, and its applications. The preparation method is complex, requiring staged heating and cooling. Diphenyl silicone oil and anti-dissolving agents are added after the base rubber is mixed, resulting in a complex and inefficient mixing process. Furthermore, it uses 6-12 parts of diphenyl silicone oil, combined with modified aluminum hydroxide, kaolin, and calcium carbonate as anti-dissolving agents to achieve self-lubrication and resistance to phosphoric acid during heat aging. However, the large amount of diphenyl silicone oil still results in a low Mooney viscosity and poor processing performance. The use of fillers such as modified aluminum hydroxide, kaolin, and calcium carbonate also increases product density and reduces tensile strength, tensile strength, and tear strength. The invention also fails to address how to improve oil resistance.

[0005] It is evident that none of the aforementioned existing technologies have improved the oil resistance of self-lubricating silicone rubber materials.

[0006] Therefore, there is an urgent need to develop a self-lubricating silicone rubber with good self-lubricating properties, resistance to long-term thermal aging, oil resistance, low compression set, and mechanical properties. Summary of the Invention

[0007] To overcome the shortcomings of existing technologies, a self-lubricating silicone rubber and its preparation method are proposed. Specifically, by providing a self-synthesized self-lubricating agent, the resulting compound is guaranteed to possess self-lubricating properties, low compression set, heat aging resistance, and acid resistance, thus meeting the requirements for connector applications. Furthermore, the preparation method for this silicone rubber is simple; the resulting silicone rubber has moderate Mooney viscosity, facilitating injection molding and exhibiting good processing performance.

[0008] To achieve the above technical objectives, the following technical solution is proposed:

[0009] The primary objective of this technical solution is to provide: a self-lubricating silicone rubber, comprising the following components by weight:

[0010] 100 parts of methyl vinyl silicone rubber (raw rubber), 5-10 parts of hydroxyl fluorosilicone oil, 25-60 parts of silica, 1-5 parts of vinyl fluorosilicone oil, 0.5-1.5 parts of treatment agent, 2-5 parts of heat resistant agent, 4-6 parts of self-lubricating agent, 0.02-0.05 parts of low-pressure modifier, and 1-2 parts of vulcanizing agent.

[0011] Furthermore, the methyl vinyl silicone rubber is composed of two methyl vinyl silicone rubbers with different vinyl contents, specifically including 50-100 parts of methyl vinyl silicone rubber raw rubber A and 0-50 parts of methyl vinyl silicone rubber raw rubber B.

[0012] Among them, the molecular weight of methyl vinyl silicone rubber raw material A is 650,000 to 1,000,000, and the vinyl content is 0.07% to 0.1%; the molecular weight of methyl vinyl silicone rubber raw material B is 650,000 to 1,000,000, and the vinyl content is 0.15% to 0.23%.

[0013] Furthermore, the hydroxyl content in the hydroxyl fluorosilicone oil is ≥7%.

[0014] Furthermore, the specific surface area of ​​the silica is 100–250 m². 2 / g.

[0015] Furthermore, the vinyl fluorosilicone oil contains 5-15% vinyl content.

[0016] Furthermore, the treatment agent is one or a mixture of any two or more of vinyltriethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, and vinyltrimethoxysilane.

[0017] Furthermore, the heat-resistant agent is one or a mixture of any two or more of titanium dioxide, cerium oxide, ferric oxide, and lanthanum oxide.

[0018] Furthermore, the structural formula of the self-lubricating agent is:

[0019]

[0020] Wherein, R1 is methyl, ethyl, phenyl, or a straight-chain structure with the same structure as the other three arms in the self-lubricating agent's structural formula. R2 is n-butyl, ethyl, propyl, isopropyl, sec-butyl, pentyl, hexyl, or trimethylsilyl ether, m is an integer from 0 to 5, n is an integer from 0 to 5, and m+n≤5.

[0021] Furthermore, the preparation method of the self-lubricating agent is as follows:

[0022] Under a nitrogen atmosphere, hexaphenylcyclotrisiloxane, trimethyltriphenylcyclotrisiloxane, lithium silanolate with R2 group and toluene were added to a three-necked flask and stirred at 0–40 °C for 8–24 h. Then, methyltrichlorosilane or tetrachlorosilane was slowly added dropwise to the reaction system. After the addition was complete, the reaction was continued at 25 °C for 2–8 h. After the reaction was completed, the solvent was removed by vacuum distillation and the lithium chloride was removed by filtration to obtain the branched self-lubricating agent.

[0023] Furthermore, the structural formula of the low-pressure variable agent is:

[0024]

[0025] Where R3 is hydrogen, fluorine, methyl or methoxy, and z is an integer from 4 to 12.

[0026] Furthermore, the preparation method of the low-pressure transformer is as follows:

[0027] Phenylacetazole carboxylic acid containing the R3 group and an alkyl alcohol containing 4 to 12 carbon atoms are dissolved in a solvent, added to a reactor and mixed thoroughly. The mixture is stirred at room temperature, and then 1-ethyl-(3-dimethylaminopropyl)carbodiimide and (4-dimethylaminopyridine) are added. The mixture is stirred at 0 to 40 °C for 12 to 48 h. The mixture is filtered, the filtrate is concentrated and dissolved in ethyl acetate, and purified by silica gel chromatography to obtain a low-pressure modifier.

[0028] Furthermore, the vulcanizing agent is 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane.

[0029] The second objective of this technical solution is to provide a method for preparing self-lubricating silicone rubber, comprising the following steps:

[0030] S1: Add methyl vinyl silicone rubber, hydroxyl fluorosilicone oil, vinyl fluorosilicone oil, heat resistant agent, self-lubricating agent and low pressure modifier to the kneader;

[0031] S2: Add the silica and treatment agent to the kneader in 3 to 5 batches, with an interval of 30 to 45 minutes between each addition;

[0032] S3: Then, mix for 30-50 minutes, heat to 140-185℃, vacuum for 2-4 hours, vacuum degree ≥0.08MPa, and discharge the adhesive to obtain the base rubber compound.

[0033] S4: After the base rubber compound has cooled for 12 hours, filter it; then, add the vulcanizing agent on the double roller and pass it through 20 times to obtain the rubber compound containing the vulcanizing agent, and set it aside.

[0034] S5: The rubber compound containing the vulcanizing agent is molded at a temperature of 165-185℃ for 10-15 minutes to obtain primary vulcanized silicone rubber; the primary vulcanized silicone rubber is vulcanized at a temperature of 180-200℃ for 2-5 hours to obtain secondary vulcanization, thus obtaining silicone rubber.

[0035] The beneficial technical effects of adopting this technical solution are as follows:

[0036] I. In this invention, a self-made self-lubricating agent is used. A small amount can achieve a good self-lubricating effect, which can avoid the pollution and swelling of other parts caused by excessive oil seepage. It has little impact on the mechanical properties and thermal aging properties of silicone rubber, and can also improve the compression set properties of the rubber compound. When used in combination with hydroxyl fluorosilicone oil and vinyl fluorosilicone oil, it will not affect its acid and solvent resistance.

[0037] Second, in this invention, the combined use of hydroxyl fluorosilicone oil and vinyl fluorosilicone oil effectively improves the acid and oil resistance of the rubber compound, and can effectively improve the service life of silicone rubber products in high-temperature and complex environments.

[0038] Third, in this invention, a low-pressure modifier is used, and a small amount can effectively improve the compression set performance of the rubber compound, and the method of use is simple.

[0039] Fourth, the preparation process involved in this invention is simple and can be achieved using mature and conventional silicone rubber production equipment in the field, which can effectively improve production efficiency. Attached Figure Description

[0040] Figure 1 This is a physical image of a connector for new energy vehicles assembled using this self-lubricating silicone rubber material (sealing ring) in an application example;

[0041] Figure 2 This is a photograph of a sealing ring made of this self-lubricating silicone rubber material after long-term thermal aging, as shown in an application example. Detailed Implementation

[0042] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0043] Example 1

[0044] This embodiment provides a self-lubricating silicone rubber, which, by weight, comprises the following components:

[0045]

[0046] Of the above components, the molecular weight of methyl vinyl silicone rubber raw rubber A is 1 million, and the vinyl content is 0.07%; the hydroxyl content of the hydroxyl fluorosilicone oil is 7%; and the specific surface area of ​​the silica is 250 m². 2 / g; the vinyl content in the vinyl fluorosilicone oil is 5%; the treatment agent is a mixture of vinyltriethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, and vinyltrimethoxysilane; the heat resistant agent is a mixture of titanium dioxide and cerium oxide; the vulcanizing agent is 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane; the self-lubricating aid is a compound having the following structural formula:

[0047]

[0048] The following NMR characterization data are available for this self-lubricating agent: 1 H NMR (400MHz, CDCl3), δ (ppm): 7.75-7.25 (150H,-Si- Ph ),1.45(6H,-Si(-Ph)2-C H 2-CH2-CH2-CH3),1.40-1.10(12H,-Si(-Ph)2-CH2-C H 2-C H 2-CH3),0.89(9H,-Si(-Ph)2-CH2-CH2-CH2-C H 3), 0.19(3H,-Si-C H 3).

[0049] The preparation method of the self-lubricating agent in this embodiment includes the following steps:

[0050] Under a nitrogen atmosphere, 595 g of hexaphenylcyclotrisiloxane (1 mol), 240 mL of n-butyllithium solution (2.5 M n-hexane solution) and 300 mL of tetrahydrofuran were added to a three-necked flask and stirred at 25 °C for 24 h. Then, 30 g (0.2 mol) of methyltrichlorosilane was slowly added dropwise to the reaction system. After the addition was complete, the reaction was continued at 25 °C for 12 h. After the reaction was completed, the solvent was removed by vacuum distillation and the lithium chloride salt was removed by filtration to obtain the self-lubricating agent (1000 mPa·s).

[0051] Low-pressure transformer additives are compounds having the following structural formula:

[0052]

[0053] The following NMR characterization data are available for this low-pressure transformer aid: 1 H NMR (400MHz, DMSO), δ (ppm): 1.5 (1H,- NH -N=N), 2.9-3.1(2H,-NH-C H 2-CH), 5.44(H, -N=NC H -CH2), 7.26-7.87(3H,- Ph -CH3), 4.15-4.35(2H,-COO-C H 2-), 1.01-1.91(9H,-C H 2-C H2 -C H2 -C H 3).

[0054] The preparation method of the low-pressure transformer in this embodiment includes the following steps:

[0055] 441g of methylphenyltriazole carboxylic acid and 167g of hexanol were dissolved in tetrahydrofuran, added to a reactor and mixed thoroughly. The mixture was stirred at room temperature, and then 261g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 24.1g of 4-dimethylaminopyridine were added. The mixture was stirred at 0–40°C for 24 h. After the reaction was completed, the mixture was filtered, the filtrate was concentrated, dissolved in 150ml of ethyl acetate, and purified by silica gel chromatography to obtain a low-pressure modifier (475g).

[0056] Then, this embodiment provides a method for preparing a suitable self-lubricating silicone rubber, including the following steps:

[0057] Step A: Add all of the methyl vinyl silicone rubber raw rubber A, hydroxyl fluorosilicone oil, vinyl fluorosilicone oil, heat resistant agent, self-lubricating agent and low-pressure modifier to the kneader;

[0058] Step B: Add the silica and treatment agent to the kneader in 3 batches, with an interval of 30 minutes between each addition;

[0059] Step C: After adding all the silica and treatment agent, mix for 30 minutes, heat to 140℃, start vacuuming, vacuum time for 4 hours, vacuum degree 0.08MPa, and then discharge the adhesive to obtain the mixed rubber base.

[0060] Step D: After the mixed rubber base has cooled for 12 hours, filter it, then add the vulcanizing agent on a double roller, and pass it through a thin pass 20 times. Set aside for later use.

[0061] Step E: The rubber compound containing the vulcanizing agent is molded at 165℃ for 10 minutes to obtain primary vulcanized silicone rubber. The primary vulcanized silicone rubber is then subjected to secondary vulcanization at 180℃ for 2 hours to obtain self-lubricating silicone rubber. The performance test results are shown in Table 1 below.

[0062] Example 2

[0063] This embodiment provides a self-lubricating silicone rubber, which, by weight, comprises the following components:

[0064]

[0065] Of the above components, methyl vinyl silicone rubber raw material A has a molecular weight of 650,000 and a vinyl content of 0.08%; methyl vinyl silicone rubber raw material B has a molecular weight of 1,000,000 and a vinyl content of 0.22%; the hydroxyl content in the hydroxyl fluorosilicone oil is 9%; and the specific surface area of ​​the silica is 200 m². 2 / g; the vinyl content in the vinyl fluorosilicone oil is 6%; the treatment agent is γ-methacryloyloxypropyltrimethoxysilane; the heat resistant agent is titanium dioxide; the vulcanizing agent is 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane; the self-lubricating aid is a compound having the following structural formula:

[0066]

[0067] The following NMR characterization data are available for this self-lubricating agent: 1 H NMR (400MHz, CDCl3), δ (ppm): 7.75-7.25 (60H,-Si- Ph ),0.20(30H,-Si-C H 3).

[0068] The preparation method of the self-lubricating agent in this embodiment includes the following steps:

[0069] Under a nitrogen atmosphere, 595 g (1 mol) of hexaphenylcyclotrisiloxane, 144 g (1.5 mol) of lithium trimethylsilanolate and 500 mL of tetrahydrofuran were added to a three-necked flask and stirred at 25 °C for 24 h. Then, 75 g (0.5 mol) of methyltrichlorosilane was slowly added dropwise to the reaction system. After the addition was complete, the reaction was continued at 25 °C for 12 h. After the reaction was completed, the solvent was removed by vacuum distillation and the lithium chloride salt was removed by filtration to obtain the self-lubricating agent (400 mPa·s).

[0070] Low-pressure transformer additives are compounds having the following structural formula:

[0071]

[0072] The following NMR characterization data are available for this low-pressure transformer aid: 1 H NMR (400MHz, DMSO), δ (ppm): 1.5 (1H,- NH -N=N), 2.9-3.1(2H,-NH-C H 2-CH), 5.44(H, -N=NC H -CH2), 7.31-7.93(4H,- Ph -CH3), 4.01-4.30(2H,-COO-C H 2-), 1.30(3H,-C H 3).

[0073] The preparation method of the low-pressure transformer in this embodiment includes the following steps:

[0074] 425g of phenyltriazole carboxylic acid and 96g of ethanol were dissolved in tetrahydrofuran, added to a reactor, and mixed thoroughly. The mixture was stirred at room temperature, and then 261g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 24.1g of 4-dimethylaminopyridine were added. The mixture was stirred at 0–40°C for 24 h. After the reaction was complete, the mixture was filtered, the filtrate was concentrated, dissolved in 150ml of ethyl acetate, and purified by silica gel column chromatography to obtain 401g of the low-pressure modifier.

[0075] Then, this embodiment provides a method for preparing a suitable self-lubricating silicone rubber, including the following steps:

[0076] Step A: Add methyl vinyl silicone rubber raw A, methyl vinyl silicone rubber raw B, hydroxyl fluorosilicone oil, vinyl fluorosilicone oil, heat resistant agent, self-lubricating agent and low pressure modifier to the kneader;

[0077] Step B: Add the silica and treatment agent to the kneader in 5 batches, with an interval of 45 minutes between each addition;

[0078] Step C: After adding all the silica and treatment agent, mix for 30 minutes, heat to 185℃, start vacuuming, vacuum time for 2 hours, vacuum degree 0.1MPa, and then discharge the adhesive to obtain the mixed rubber base.

[0079] Step D: After the mixed rubber base has cooled for 12 hours, filter it, then add the vulcanizing agent on a double roller, and pass it through a thin pass 20 times. Set aside for later use.

[0080] Step E: The rubber compound containing the vulcanizing agent is molded at 185℃ for 15 minutes to obtain primary vulcanized silicone rubber. The primary vulcanized silicone rubber is then subjected to secondary vulcanization at 200℃ for 5 hours to obtain self-lubricating silicone rubber. The performance test results are shown in Table 1 below.

[0081] Example 3

[0082] This embodiment provides a self-lubricating silicone rubber, which, by weight, comprises the following components:

[0083]

[0084] Of the above components, methyl vinyl silicone rubber raw material A has a molecular weight of 700,000 and a vinyl content of 0.1%; methyl vinyl silicone rubber raw material B has a molecular weight of 650,000 and a vinyl content of 0.18%; the hydroxyl content in the hydroxyl fluorosilicone oil is 8%; and the specific surface area of ​​the silica is 130 m². 2 / g; the vinyl content in the vinyl fluorosilicone oil is 8%; the treatment agent is vinyltriethoxysilane; the heat resistant agent is a mixture of titanium dioxide and lanthanum oxide; the vulcanizing agent is 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane; the self-lubricating aid is a compound having the following structural formula:

[0085]

[0086] The following NMR characterization data are available for this self-lubricating agent: 1 H NMR (400MHz, CDCl3), δ (ppm): 7.75-7.25 (45H,-Si- Ph ),0.98(30H,-Si-C-(C H 3)3,-Si-CH2-C H 3), 0.68-0.60(29H,-Si-C) H 3,-Si-C H 2-CH3).

[0087] The preparation method of the self-lubricating agent in this embodiment includes the following steps:

[0088] Under a nitrogen atmosphere, 408 g (1 mol) of 2,4,6-trimethyl-2,4,6-triphenylcyclotrisiloxane, 526 mL of tert-butyllithium (1.9 M pentane solution), and 200 mL of tetrahydrofuran were added to a three-necked flask and stirred at 25 °C for 24 h. Then, 54.7 g (0.33 mol) of ethyltrichlorosilane was slowly added dropwise to the reaction system. After the addition was complete, the reaction was continued at 25 °C for 12 h. After the reaction was completed, the solvent was removed by vacuum distillation, and the lithium chloride salt was removed by filtration to obtain the self-lubricating agent (500 mPa·s).

[0089] Low-pressure transformer additives are compounds having the following structural formula:

[0090]

[0091] The following NMR characterization data are available for this low-pressure transformer aid: 1 H NMR (400MHz, DMSO), δ (ppm): 1.5 (1H,- NH -N=N), 2.9-3.1(2H,-NH-C H 2-CH), 5.44(H, -N=NC H -CH2), 7.46-7.87(3H,- Ph -CH3), 2.44-2.59(2H,-Ph-C H 2-CH3), 1.21-1.38(3H,-Ph-CH2-C H3 ), 4.15-4.35(2H,-COO-C H 2-), 0.88-1.78(19H,-C H 2-C H2 -C H2 -C H 3).

[0092] The preparation method of the low-pressure transformer in this embodiment includes the following steps:

[0093] 463g of ethylphenyltriazole carboxylic acid and 372g of nonanol were dissolved in tetrahydrofuran, added to a reactor and mixed thoroughly. The mixture was stirred at room temperature, and then 261g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 24.1g of 4-dimethylaminopyridine were added. The mixture was stirred at 0–40°C for 48 h. After the reaction was completed, the mixture was filtered, the filtrate was concentrated, dissolved in 200ml of ethyl acetate, and purified by silica gel chromatography to obtain a low-pressure modifier (695g).

[0094] Then, this embodiment provides a method for preparing a suitable self-lubricating silicone rubber, including the following steps:

[0095] Step A: Add methyl vinyl silicone rubber raw A, methyl vinyl silicone rubber raw B, hydroxyl fluorosilicone oil, vinyl fluorosilicone oil, heat resistant agent, self-lubricating agent, and low-pressure modifier to the kneader;

[0096] Step B: Add the silica and treatment agent to the kneader in 5 batches, with an interval of 40 minutes between each addition;

[0097] Step C: After adding all the silica and treatment agent, mix for 50 minutes, heat to 170℃, start vacuuming, vacuum time for 3.5 hours, vacuum degree 0.09MPa, and then discharge the rubber to obtain the mixed rubber base.

[0098] Step D: After the mixed rubber base has cooled for 12 hours, filter it, then add the vulcanizing agent on a double roller, and pass it through a thin pass 20 times. Set aside for later use.

[0099] Step E: The rubber compound containing the vulcanizing agent is molded at 175℃ for 12 minutes to obtain primary vulcanized silicone rubber. The primary vulcanized silicone rubber is then subjected to secondary vulcanization at 200℃ for 3 hours to obtain self-lubricating silicone rubber. The performance test results are shown in Table 1 below.

[0100] Example 4

[0101] This embodiment provides a self-lubricating silicone rubber, which, by weight, comprises the following components:

[0102]

[0103] Of the above components, methyl vinyl silicone rubber raw material A has a molecular weight of 700,000 and a vinyl content of 0.08%; methyl vinyl silicone rubber raw material B has a molecular weight of 750,000 and a vinyl content of 0.16%; the hydroxyl content in the hydroxyl fluorosilicone oil is 7%; and the specific surface area of ​​the silica is 200 m². 2 / g; the vinyl content in the vinyl fluorosilicone oil is 6%; the treatment agent is vinyltrimethoxysilane; the heat resistant agent is a mixture of titanium dioxide and cerium oxide; the vulcanizing agent is 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane; the self-lubricating aid is a compound having the following structural formula:

[0104]

[0105] The following NMR characterization data are available for this self-lubricating agent: 1 H NMR (400MHz, CDCl3), δ (ppm): 7.75-7.25 (45H,-Si- Ph ),1.43(6H,-Si(-Ph)(-CH3)-C H2-CH2-CH2-CH3),1.40-1.10(12H,-Si(-Ph)(-CH3)-CH2-C H 2-C H 2-CH3),0.90(12H,-Si(-Ph)(-CH3)-CH2-CH2-CH2-C H 3,-Si-CH2-C H 3), 0.68-0.60(11H,-Si-C) H 3,-Si-C H 2-CH3).

[0106] The preparation method of the self-lubricating agent in this embodiment includes the following steps:

[0107] Under a nitrogen atmosphere, 298 g (0.5 mol) of hexaphenylcyclotrisiloxane, 204 g (0.5 mol) of 2,4,6-trimethyl-2,4,6-triphenylcyclotrisiloxane, 600 mL of n-butyllithium solution (2.5 M n-hexane solution) and 200 mL of toluene were added to a three-necked flask and stirred at 25 °C for 24 h. Then, 82 g (0.5 mol) of ethyltrichlorosilane was slowly added dropwise to the reaction system. After the addition was complete, the reaction was continued at 25 °C for 12 h. After the reaction was completed, the solvent was removed by vacuum distillation and the lithium chloride salt was removed by filtration to obtain the self-lubricating agent (300 mPa·s).

[0108] Low-pressure transformer additives are compounds having the following structural formula:

[0109]

[0110] The following NMR characterization data are available for this low-pressure transformer aid: 1 H NMR (400MHz, DMSO), δ (ppm): 1.5 (1H,- NH -N=N), 2.9-3.1(2H,-NH-C H 2-CH), 5.44(H, -N=NC H -CH2), 7.46-7.87(3H,- Ph -CH3), 2.44-2.59(2H,-Ph-C H 2-CH3), 1.21-1.38(3H,-Ph-CH2-C H3 ), 4.15-4.35(2H,

[0111] -COO-C H 2-), 0.88-1.78(15H,-C H 2-C H2 -C H2 -CH 3).

[0112] The preparation method of the low-pressure transformer in this embodiment includes the following steps:

[0113] 463g of phenyltriazole carboxylic acid and 340g of octanol were dissolved in tetrahydrofuran, added to a reactor and mixed thoroughly. The mixture was stirred at room temperature, and then 261g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 24.1g of 4-dimethylaminopyridine were added. The mixture was stirred at 0–40°C for 36 h. After the reaction was completed, the mixture was filtered, the filtrate was concentrated, dissolved in 150ml of ethyl acetate, and purified by silica gel chromatography to obtain a low-pressure modifier (695g).

[0114] Then, this embodiment provides a method for preparing a suitable self-lubricating silicone rubber, including the following steps:

[0115] Step A: Add methyl vinyl silicone rubber raw A, methyl vinyl silicone rubber raw B, hydroxyl fluorosilicone oil, vinyl fluorosilicone oil, heat resistant agent, self-lubricating agent, and low-pressure modifier to the kneader;

[0116] Step B: Add the silica and treatment agent to the kneader in 4 batches, with an interval of 35 minutes between each addition;

[0117] Step C: After adding all the silica and treatment agent, mix for 30 minutes, heat to 180℃, start vacuuming, vacuum time for 4 hours, vacuum degree 0.1MPa, and then discharge the rubber to obtain the mixed rubber base.

[0118] Step D: After the mixed rubber base has cooled for 12 hours, filter it, then add the vulcanizing agent on a double roller and pass it through 20 times for later use.

[0119] Step E: The rubber compound containing the vulcanizing agent is molded at 175℃ for 13 minutes to obtain primary vulcanized silicone rubber. The primary vulcanized silicone rubber is then subjected to secondary vulcanization at 200℃ for 4 hours to obtain self-lubricating silicone rubber. The performance test results are shown in Table 1 below.

[0120] Example 5

[0121] This embodiment provides a self-lubricating silicone rubber, which, by weight, comprises the following components:

[0122]

[0123] Of the above components, methyl vinyl silicone rubber raw material A has a molecular weight of 780,000 and a vinyl content of 0.09%; methyl vinyl silicone rubber raw material B has a molecular weight of 700,000 and a vinyl content of 0.18%; the hydroxyl content in the hydroxyl fluorosilicone oil is 8%; and the specific surface area of ​​the silica is 160 m².2 / g; the vinyl content in the vinyl fluorosilicone oil is 7%; the treatment agent is vinyltrimethoxysilane; the heat resistant agent is a mixture of cerium oxide and lanthanum oxide; the vulcanizing agent is 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane; the self-lubricating aid is a compound having the following structural formula:

[0124]

[0125] The following NMR characterization data are available for this self-lubricating agent: 1 H NMR (400MHz, CDCl3), δ (ppm): 7.75-7.25 (80H,-Si- Ph ),0.98(27H,-Si-C-(C H 3)3),0.66(45H,-Si-C H 3).

[0126] The preparation method of the self-lubricating agent in this embodiment includes the following steps:

[0127] Under a nitrogen atmosphere, 408 g (1 mol) of 2,4,6-trimethyl-2,4,6-triphenylcyclotrisiloxane, 316 mL of tert-butyllithium (1.9 M pentane solution), and 500 mL of tetrahydrofuran were added to a three-necked flask and stirred at 25 °C for 24 h. Then, 42.4 g (0.2 mol) of phenyltrichlorosilane was slowly added dropwise to the reaction system. After the addition was complete, the reaction was continued at 25 °C for 12 h. After the reaction was completed, the solvent was removed by vacuum distillation, and the lithium chloride salt was removed by filtration to obtain the self-lubricating agent (800 mPa·s).

[0128] Low-pressure transformer additives are compounds having the following structural formula:

[0129]

[0130] The following NMR characterization data are available for this low-pressure transformer aid: 1 H NMR (400MHz, DMSO), δ (ppm): 1.5 (1H,- NH -N=N), 2.9-3.1(2H,-NH-C H 2-CH), 5.44(H, -N=NC H -CH2), 7.31-7.61(3H,- Ph -O-CH3), 3.44-3.72(3H,-Ph-OC) H 3), 4.22-4.35(2H,-COO-C H 2-), 1.05-1.78(5H,-C H 2-CH 3).

[0131] The preparation method of the low-pressure transformer in this embodiment includes the following steps:

[0132] 466g of methoxyphenyltriazole carboxylic acid and 112g of propanol were dissolved in tetrahydrofuran, added to a reactor and mixed thoroughly. The mixture was stirred at room temperature, and then 261g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 24.1g of 4-dimethylaminopyridine were added. The mixture was stirred at 0–40°C for 12 h. After the reaction was completed, the mixture was filtered, the filtrate was concentrated and dissolved in 150ml of ethyl acetate, and purified by silica gel chromatography to obtain a low-pressure modifier (498g).

[0133] Then, this embodiment provides a method for preparing a suitable self-lubricating silicone rubber, including the following steps:

[0134] Step A: Add methyl vinyl silicone rubber raw A, methyl vinyl silicone rubber raw B, hydroxyl fluorosilicone oil, vinyl fluorosilicone oil, heat resistant agent, self-lubricating agent and low pressure modifier to the kneader.

[0135] Step B: Add the silica and treatment agent to the kneader in 4 batches, with an interval of 40 minutes between each addition.

[0136] Step C: After adding all the silica and treatment agent, mix for 30 minutes, heat to 165℃, start vacuuming, vacuum time for 3 hours, vacuum degree 0.09MPa, and then discharge the adhesive to obtain the mixed rubber base.

[0137] Step D: After the mixed rubber base has cooled for 12 hours, filter it, then add the vulcanizing agent on a double roller, and pass it through 20 times in a thin pass for later use;

[0138] Step E: The rubber compound containing the vulcanizing agent is molded at 175℃ for 12 minutes to obtain primary vulcanized silicone rubber. The primary vulcanized silicone rubber is then subjected to secondary vulcanization at 190℃ for 4 hours to obtain self-lubricating silicone rubber. The performance test results are shown in Table 1 below.

[0139] Example 6

[0140] This embodiment provides a self-lubricating silicone rubber, which, by weight, comprises the following components:

[0141]

[0142]

[0143] Of the above components, methyl vinyl silicone rubber raw material A has a molecular weight of 750,000 and a vinyl content of 0.07%; methyl vinyl silicone rubber raw material B has a molecular weight of 750,000 and a vinyl content of 0.2%; the hydroxyl content in the hydroxyl fluorosilicone oil is 9%; and the specific surface area of ​​the silica is 210 m². 2 / g; Vinyl content in vinyl fluorosilicone oil is 6%; Treatment agent is vinyltrimethoxysilane; Heat resistant agent is a mixture of titanium dioxide, cerium oxide and ferric oxide; Vulcanizing agent is 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane; Self-lubricating agent is a compound having the following structural formula:

[0144]

[0145] The following NMR characterization data are available for this self-lubricating agent: 1 H NMR (400MHz, CDCl3), δ (ppm): 7.75-7.25 (35H,-Si- Ph ),0.66(18H,-Si-C H 3), 0.20(27H,-Si-(C H 3)3).

[0146] The preparation method of the self-lubricating agent in this embodiment includes the following steps:

[0147] Under a nitrogen atmosphere, 408 g (1 mol) of 2,4,6-trimethyl-2,4,6-triphenylcyclotrisiloxane, 144 g (1.5 mol) of lithium trimethylsilanolate and 600 mL of tetrahydrofuran were added to a three-necked flask and stirred at 25 °C for 24 h. Then, 106 g (0.5 mol) of phenyltrichlorosilane was slowly added dropwise to the reaction system. After the addition was complete, the reaction was continued at 25 °C for 12 h. After the reaction was completed, the solvent was removed by vacuum distillation and the lithium chloride salt was removed by filtration to obtain the self-lubricating agent (200 mPa·s).

[0148] Low-pressure transformer additives are compounds having the following structural formula:

[0149]

[0150] The following NMR characterization data are available for this low-pressure transformer aid: 1 H NMR (400MHz, DMSO), δ (ppm): 1.5 (1H,- NH -N=N), 2.9-3.1(2H,-NH-C H 2-CH), 5.44(H, -N=NC H -CH2), 7.31-7.61(3H,- Ph-O-CH3), 3.44-3.72(3H,-Ph-OC) H 3), 4.22-4.35(2H,-COO-C H 2-), 0.90-1.74(11H,-C H 2-C H 3).

[0151] The preparation method of the low-pressure transformer in this embodiment includes the following steps:

[0152] 466g of methoxyphenyltriazole carboxylic acid and 156g of pentanol were dissolved in tetrahydrofuran, added to a reactor and mixed thoroughly. The mixture was stirred at room temperature, and then 261g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 24.1g of 4-dimethylaminopyridine were added. The mixture was stirred at 0–40°C for 24 h. After the reaction was completed, the mixture was filtered, the filtrate was concentrated and dissolved in 150ml of ethyl acetate, and purified by silica gel chromatography to obtain a low-pressure modifier (523g).

[0153] Then, this embodiment provides a method for preparing a suitable self-lubricating silicone rubber, including the following steps:

[0154] Step A: Add methyl vinyl silicone rubber raw A, methyl vinyl silicone rubber raw B, hydroxyl fluorosilicone oil, vinyl fluorosilicone oil, heat resistant agent, self-lubricating agent and low pressure modifier to the kneader;

[0155] Step B: Add the silica and treatment agent to the kneader in 4 batches, with an interval of 40 minutes between each addition;

[0156] Step C: After adding all the silica and treatment agent, mix for 30 minutes, heat to 175℃, start vacuuming, vacuum time for 3 hours, vacuum degree 0.09MPa, and then discharge the adhesive to obtain the mixed rubber base.

[0157] Step D: After the mixed rubber base has cooled for 12 hours, filter it, then add the vulcanizing agent on a double roller, and pass it through a thin pass 20 times. Set aside for later use.

[0158] Step E: The rubber compound containing the vulcanizing agent is molded at 175℃ for 12 minutes to obtain primary vulcanized silicone rubber. The primary vulcanized silicone rubber is then subjected to secondary vulcanization at 190℃ for 4 hours to obtain self-lubricating silicone rubber. The performance test results are shown in Table 1 below.

[0159] Example 7

[0160] This embodiment provides a self-lubricating silicone rubber, which, by weight, comprises the following components:

[0161]

[0162]

[0163] Of the above components, methyl vinyl silicone rubber raw material A has a molecular weight of 650,000 and a vinyl content of 0.08%; methyl vinyl silicone rubber raw material B has a molecular weight of 800,000 and a vinyl content of 0.21%; the hydroxyl content in the hydroxyl fluorosilicone oil is 9%; and the specific surface area of ​​the silica is 180m². 2 / g; the vinyl content in the vinyl fluorosilicone oil is 7%; the treatment agent is vinyltrimethoxysilane; the heat resistant agent is a mixture of titanium dioxide and ferric oxide; the vulcanizing agent is 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane; the self-lubricating aid is a compound having the following structural formula:

[0164]

[0165] The following NMR characterization data are available for this self-lubricating agent: 1 H NMR (400MHz, CDCl3), δ (ppm): 7.75-7.25 (100H,-Si- Ph ),1.43(8H,-Si(-Ph)(-CH3)-C H 2-CH2-CH2-CH3),1.40-1.10(16H,-Si(-Ph)(-CH3)-CH2-C H 2-C H 2-CH3),0.90(12H,-Si(-Ph)(-CH3)-CH2-CH2-CH2-C H 3), 0.66(12H,-Si-C H 3).

[0166] The preparation method of the self-lubricating agent in this embodiment includes the following steps:

[0167] Under a nitrogen atmosphere, 298 g (0.5 mol) of hexaphenylcyclotrisiloxane, 102 g (0.25 mol) of 2,4,6-trimethyl-2,4,6-triphenylcyclotrisiloxane, 300 mL of n-butyllithium solution (2.5 M n-hexane solution) and 300 mL of tetrahydrofuran were added to a three-necked flask and stirred at 25 °C for 24 h. Then, 32 g (0.19 mol) of tetrachlorosilane was slowly added dropwise to the reaction system. After the addition was complete, the reaction was continued at 25 °C for 12 h. After the reaction was completed, the solvent was removed by vacuum distillation and the lithium chloride salt was removed by filtration to obtain the self-lubricating agent (700 mPa·s).

[0168] Low-pressure transformer additives are compounds having the following structural formula:

[0169]

[0170] The following NMR characterization data are available for this low-pressure transformer aid: 1 H NMR (400MHz, DMSO), δ (ppm): 1.5 (1H,- NH -N=N), 2.9-3.1(2H,-NH-C H 2-CH), 5.44(H, -N=NC H -CH2), 7.29-7.71(3H,- Ph -O-CH3), 4.18-4.35(2H,-COO-C H 2-), 1.20-1.34(3H,-C H 3).

[0171] The preparation method of the low-pressure transformer in this embodiment includes the following steps:

[0172] 472g of fluorophenyltriazole carboxylic acid and 98g of ethanol were dissolved in tetrahydrofuran, added to a reactor and mixed thoroughly. The mixture was stirred at room temperature, and then 261g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 24.1g of 4-dimethylaminopyridine were added. The mixture was stirred at 0-40℃ for 24h. After the reaction was completed, the mixture was filtered, the filtrate was concentrated, dissolved in 150ml of ethyl acetate, and purified by silica gel chromatography to obtain a low-pressure modifier (398g).

[0173] Then, this embodiment provides a method for preparing a suitable self-lubricating silicone rubber, including the following steps:

[0174] Step A: Add methyl vinyl silicone rubber raw A, methyl vinyl silicone rubber raw B, hydroxyl fluorosilicone oil, vinyl fluorosilicone oil, heat resistant agent, self-lubricating agent and low pressure modifier to the kneader;

[0175] Step B: Add the silica and treatment agent to the kneader in 4 batches, with an interval of 40 minutes between each addition;

[0176] Step C: After adding all the silica and treatment agent, mix for 30 minutes, heat to 175℃, start vacuuming, vacuum time for 3 hours, vacuum degree 0.09MPa, and then discharge the adhesive to obtain the mixed rubber base.

[0177] Step D: After the mixed rubber base has cooled for 12 hours, filter it, then add the vulcanizing agent on a double roller, and pass it through a thin pass 20 times. Set aside for later use.

[0178] Step E: The rubber compound containing the vulcanizing agent is molded at 175℃ for 12 minutes to obtain primary vulcanized silicone rubber. The primary vulcanized silicone rubber is then subjected to secondary vulcanization at 190℃ for 4 hours to obtain self-lubricating silicone rubber. The performance test results are shown in Table 1 below.

[0179] Comparative Example 1

[0180] Based on Example 4, this comparative example mainly examines the compression set, acid resistance, long-term heat aging resistance and oil resistance of the rubber compound when hydroxyl fluorosilicone oil is not used.

[0181] In this comparative example, hydroxyl silicone oil, a common structure control agent, was used instead of hydroxyl fluorosilicone oil (i.e., no hydroxyl fluorosilicone oil was added), and the rest was the same as in Example 4. The performance test results are shown in Table 2 below.

[0182] Comparative Example 2

[0183] Based on Example 4, this comparative example mainly examines the compression set, acid resistance, long-term heat aging resistance and oil resistance of the rubber compound when vinyl fluorosilicone oil is not used.

[0184] In this comparative example, no vinyl fluorosilicone oil was added; otherwise, it was the same as in Example 4. The performance test results are shown in Table 2 below.

[0185] Comparative Example 3

[0186] Based on Example 4, this comparative example mainly examines the compression set, acid resistance, long-term heat aging resistance and oil resistance of the rubber compound when no self-lubricating agent is used.

[0187] In this comparative example, no self-lubricating agent was added; otherwise, it was the same as in Example 4. The performance test results are shown in Table 2 below.

[0188] Comparative Example 4

[0189] Based on Example 4, this comparative example mainly examines the compression set and acid and alkali resistance of the rubber compound when the order of adding hydroxyl fluorosilicone oil and vinyl fluorosilicone oil is changed during the preparation of self-lubricating silicone rubber.

[0190] In this comparative example, hydroxyl fluorosilicone oil and vinyl fluorosilicone oil were mixed for 30 minutes in step C, heated to 180°C, and then added; the rest was the same as in Example 4. The performance test results are shown in Table 2 below.

[0191] Comparative Example 5

[0192] Based on Example 4, this comparative example mainly examines the compression set, acid resistance, long-term heat aging resistance and oil resistance of the rubber compound when no low-pressure modifier is used.

[0193] In this comparative example, no low-voltage transformer additive was added; otherwise, it was the same as in Example 4. The performance test results are shown in Table 2 below.

[0194] Comparative Example 6

[0195] Based on Example 4, this comparative example mainly examines the effect of the synergistic effect of self-lubricating agent, vinyl fluorosilicone oil, and hydroxyl fluorosilicone on the acid resistance and oil resistance of the rubber compound.

[0196] In this comparative example, 9 parts of benzyl silicone oil were used to replace 5 parts of the self-lubricating agent, and the rest were the same as in Example 4. The performance test results are shown in Table 2 below.

[0197] Table 1

[0198]

[0199] Table 2

[0200]

[0201] As shown in Table 1, the self-lubricating silicone rubber prepared from the raw material components in Examples 1-7 of this invention can be oiled within 0.5 hours; the compression set (177℃*24h) is ≤9%, which shows excellent compression set performance.

[0202] In the acid resistance test at 5% sodium hypochlorite solution, 25℃*240h, the hardness of the rubber compound changed from -1 to -2, the tensile strength changed from -1.05 to -3.19%, the elongation at break changed from -0.18 to -3.99%, and the tear strength changed from -2.46 to -4.72%. This rubber compound has excellent acid resistance.

[0203] Under long-term heat aging test at 140℃*1008h, the hardness of the rubber compound changed by 1~2, the tensile strength changed by -3.1~-6.2%, the elongation at break changed by -5.3~-4.9%, the tear strength changed by -3.2~3.5%, and the compression set of the rubber compound was ≤14%. This rubber compound product has excellent resistance to long-term heat aging.

[0204] In the oil resistance test at "Mobil ATF220, 180℃*24h", the hardness change rate of the rubber compound was -3 to -1, the volume change rate was 4.1 to 6.2%, and the mass change rate was 3.5 to 4.3%. This rubber compound has excellent oil resistance.

[0205] As shown in Table 2, in Comparative Example 1, without the addition of hydroxyl fluorosilicone oil and instead using hydroxyl silicone oil, compared to Example 4, the compression set of the rubber compound deteriorated by 14.3%, the acid resistance decreased significantly, the hardness changed by -5, the tensile strength changed by -25.97%, the elongation at break changed by -37.43%, and the tear strength changed by -10.16%; the oil resistance also decreased significantly, with the hardness changing by -5, the volume change rate by 17.2%, and the mass change rate by 10.3%.

[0206] In Comparative Example 2, without the addition of vinyl fluorosilicone oil, compared to Example 4, the compression set of the rubber compound deteriorated by 18.1%, acid resistance decreased, tensile strength changed by -12.68%, elongation at break changed by -10.75%, long-term heat aging resistance decreased significantly, oil resistance decreased significantly, hardness changed by -6, volume change by 14.1%, and mass change by 8.5%.

[0207] In Comparative Example 3, no self-lubricating agent was added, and the rubber compound did not leak oil, thus failing to provide self-lubrication and not meeting the requirements of this invention. The compression set was 13.8%. Compared to Example 4, the compression set was worse, indicating that the self-lubricating agent of this invention can improve the compression set performance.

[0208] In Comparative Example 4, the order of adding hydroxyl fluorosilicone oil and vinyl fluorosilicone oil was changed. Compared with Example 4, the compression set of the rubber compound deteriorated by 20%, and the acid resistance and oil resistance decreased significantly.

[0209] In Comparative Example 5, no low-pressure modifier was added, and the compression set was significantly worse than in Example 4, with a compression set of 14.5%.

[0210] In Comparative Example 6, 9 parts of benzyl silicone oil were used to replace 5 parts of the self-lubricating agent. Compared with Comparative Example 4 and Comparative Example 3, the compression set deteriorated by 19%, mechanical properties decreased, acid resistance decreased, long-term heat aging resistance decreased, and oil resistance decreased. This indicates that the self-lubricating agent, hydroxyl fluorosilicone oil and vinyl fluorosilicone oil have a good synergistic effect.

[0211] Application examples

[0212] The self-lubricating silicone rubber material obtained in Example 4 is used as a sealing material (e.g., a sealing ring) and specifically assembled into a connector for new energy vehicles (e.g., Figure 1 (As shown).

[0213] Currently, connectors using the self-lubricating silicone rubber material obtained in Example 4 as sealing material have been actually installed and used in vehicles. A total of 5,000 vehicles were randomly selected for installation, and no quality failure complaints have occurred. The operation is in good condition.

[0214] The connectors assembled at the same time underwent thermal aging simulation in the laboratory. The simulation environment included: 150℃*128h, 177℃*72h, 140℃*1008h, high and low temperature cycling test of -40℃~140℃ for 1008h, and 30℃*365d. The sealing ring was assembled together with the PA66 component, which is a phosphorus-based flame retardant. After thermal aging, the material maintained good self-lubricating properties, and there were no obvious oil stains on other parts. However, the surface of the material showed obvious oil droplets after thermal aging (e.g., ...). Figure 2 As shown, after long-term thermal aging, no deformation occurred, and there was no swelling or cracking in the appearance, maintaining good sealing performance;

[0215] The above applications demonstrate that the self-lubricating silicone rubber of this invention possesses excellent self-lubricating properties, compression set properties, heat aging properties, acid resistance, and oil resistance.

[0216] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all the implementation methods here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A self-lubricating silicone rubber, characterized in that, Based on parts by mass, it includes the following components: 100 parts of methyl vinyl silicone rubber, 5-10 parts of hydroxyl fluorosilicone oil, 25-60 parts of silica, 1-5 parts of vinyl fluorosilicone oil, 0.5-1.5 parts of treatment agent, 2-5 parts of heat resistant agent, 4-6 parts of self-lubricating agent, 0.02-0.05 parts of low-pressure modifier, and 1-2 parts of vulcanizing agent; The structural formula of the self-lubricating agent is as follows: Wherein, R1 is methyl, ethyl, phenyl or R2 is n-butyl, ethyl, propyl, isopropyl, sec-butyl, pentyl, hexyl or trimethylsilyl ether, m is an integer from 0 to 5, n is an integer from 0 to 5, and m+n≤5; The structural formula of the low-pressure variable additive is: Where R3 is hydrogen, fluorine, methyl or methoxy, and z is an integer from 4 to 12.

2. The self-lubricating silicone rubber according to claim 1, characterized in that, The methyl vinyl silicone rubber comprises 50-100 parts of methyl vinyl silicone rubber raw material A and 0-50 parts of methyl vinyl silicone rubber raw material B; The molecular weight of methyl vinyl silicone rubber raw rubber A is 650,000 to 1,000,000, and the vinyl content is 0.07% to 0.1%. The molecular weight of methyl vinyl silicone rubber raw rubber B is 650,000 to 1,000,000, and the vinyl content is 0.15% to 0.23%.

3. The self-lubricating silicone rubber according to claim 1, characterized in that, The hydroxyl content in the hydroxyl fluorosilicone oil is ≥7%.

4. The self-lubricating silicone rubber according to claim 1, characterized in that, The specific surface area of ​​the silica is 100-250 m². 2 / g.

5. The self-lubricating silicone rubber according to claim 1, characterized in that, The vinyl fluorosilicone oil contains 5-15% vinyl content.

6. The self-lubricating silicone rubber according to claim 1, characterized in that, The treatment agent is one or a mixture of any two or more of vinyltriethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, and vinyltrimethoxysilane.

7. The self-lubricating silicone rubber according to claim 1, characterized in that, The heat-resistant agent is one or a mixture of any two or more of titanium dioxide, cerium oxide, ferric oxide, and lanthanum oxide.

8. The self-lubricating silicone rubber according to claim 1, characterized in that, The vulcanizing agent is 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane.

9. The self-lubricating silicone rubber according to any one of claims 1-8, characterized in that, The preparation method of the self-lubricating agent is as follows: Under a nitrogen atmosphere, hexaphenylcyclotrisiloxane, trimethyltriphenylcyclotrisiloxane, lithium silanolate with an R2 group, and toluene were added to a reactor and stirred at 0–40 °C for 8–24 h. Then, methyltrichlorosilane or tetrachlorosilane was added to the reaction system, and after the addition was complete, the reaction was continued at 25 °C for 2–8 h. The mixture was then distilled under reduced pressure and filtered to obtain a self-lubricating agent. The preparation method of the low-pressure transformer additive is as follows: Phenylacetazole carboxylic acid containing the R3 group and an alkyl alcohol containing 4 to 12 carbon atoms are dissolved in a solvent, added to a reactor and mixed thoroughly. The mixture is stirred at room temperature, and then 1-ethyl-(3-dimethylaminopropyl)carbodiimide and (4-dimethylaminopyridine) are added. The mixture is stirred at 0 to 40 °C for 12 to 48 h. The mixture is filtered, the filtrate is concentrated and dissolved in ethyl acetate, and purified by silica gel chromatography to obtain a low-pressure modifier.

10. A method for preparing self-lubricating silicone rubber, characterized in that, The preparation method for the self-lubricating silicone rubber according to any one of claims 1-8, the preparation method comprising the following steps: S1: Add methyl vinyl silicone rubber, hydroxyl fluorosilicone oil, vinyl fluorosilicone oil, heat resistant agent, self-lubricating agent and low pressure modifier to the kneader; S2: Add the silica and treatment agent to the kneader in 3 to 5 batches, with an interval of 30 to 45 minutes between each addition; S3: Then, mix for 30-50 minutes, heat to 140-185℃, vacuum for 2-4 hours, vacuum degree ≥0.08MPa, and discharge the adhesive to obtain the base rubber compound. S4: After the base rubber compound has cooled for 12 hours, filter it; then, add the vulcanizing agent on the double roller, pass it through 20 times in a thin pass, and perform the first vulcanization to obtain the rubber compound containing the vulcanizing agent for later use. S5: The rubber compound containing the vulcanizing agent is molded at a temperature of 165-185℃ for 10-15 minutes to obtain primary vulcanized silicone rubber; the primary vulcanized silicone rubber is vulcanized at a temperature of 180-200℃ for 2-5 hours to obtain silicone rubber.

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