Anti-aging relaxation-resistant insulating silicone rubber and preparation method thereof

Abstract

The invention relates to the technical field of silicone rubber, and particularly discloses anti-aging and relaxation-resistant insulating silicone rubber and a preparation method thereof. The anti-aging relaxation-resistant insulating silicone rubber is prepared from the following raw material components in parts by weight: 90 to 110 parts of a silicone rubber matrix, 5 to 8 parts of polyethylene, 30 to 40 parts of a reinforcing agent, 3.1 to 6 parts of a structure control agent, 0.9 to 1.3 parts of a structure adjusting agent, 2 to 6 parts of a cross-linking agent, 0.1 to 1 part of a vulcanizing aid and 1.5 to 2.5 parts of an antioxidant, the cross-linking agent is prepared from silicon dicumyl peroxide, triallyl cyanurate, a platinum vulcanizing agent and triallyl isocyanurate. The composite cross-linking agent is utilized to form a three-dimensional network structure, so that the mechanical property of the obtained insulating silicone rubber is more stable, and aging resistance and stress relaxation resistance are facilitated; and the problems of excessive crosslinking and mechanical property reduction of the insulating silicone rubber are solved.

Description

Technical Field

[0001] The present application relates to the technical field of silicone rubber, and particularly relates to an anti-aging and relaxation-resistant insulating silicone rubber and a preparation method thereof. Background Art

[0002] Due to its excellent high-temperature resistance, electrical insulation and flexibility, silicone rubber is widely used in the insulation of power cable accessories, insulation protection of electronic components and aerospace fields. However, under long-term dynamic stress or high-temperature service environments, traditional silicone rubber insulation materials are prone to problems such as stress relaxation and increased compression set, resulting in seal failure, increased contact resistance or decline in mechanical support performance, severely restricting its reliability in scenarios such as precision connectors and high-voltage cable accessories. Summary of the Invention

[0003] In order to improve the relaxation resistance of insulating silicone rubber, the present application provides an anti-aging and relaxation-resistant insulating silicone rubber and a preparation method thereof.

[0004] In the first aspect, an anti-aging and relaxation-resistant insulating silicone rubber provided by the present application adopts the following technical solution: An anti-aging and relaxation-resistant insulating silicone rubber, the raw materials of the insulating silicone rubber include the following components in parts by weight: 90-110 parts of silicone rubber matrix, 5-8 parts of polyethylene, 30-40 parts of reinforcing agent, 3.1-6 parts of structure control agent, 0.9-1.3 parts of structure adjusting agent, 2-6 parts of crosslinking agent, 0.1-1 part of vulcanization assistant, 1.5-2.5 parts of antioxidant; the crosslinking agent includes dicumyl peroxide, triallyl cyanurate, platinum curing agent, triallyl isocyanurate.

[0005] By adopting the above technical solution, the platinum curing agent in the crosslinking agent plays an addition vulcanization catalytic role. After dicumyl peroxide is decomposed by heat, it undergoes a hydrogen abstraction reaction with polyethylene molecules. Triallyl isocyanurate binds to the polyethylene molecular chain with free radicals by covalent bonds. Since there are three "-CH=CH2" groups in one molecule of triallyl isocyanurate, and each "-CH=CH2" group can bind to the polyethylene molecule with free radicals, the same molecule of triallyl isocyanurate can undergo multiple crosslinking reactions with polyethylene molecules, and the connection between molecules after its crosslinking is three-dimensional. It is difficult for silicone rubber molecular chains to move in this multi-dimensional complex structure. Therefore, the crosslinked structure formed is a stable three-dimensional network. Due to the synergistic effect of the above-mentioned dicumyl peroxide and triallyl isocyanurate, the crosslinking mode of silicone rubber molecules and the entanglement between molecules are changed, and the crosslinking degree increases with the increase of the dosage of dicumyl peroxide, and it is not easy to appear the state of "over-crosslinking". Triallyl cyanurate releases active free radicals at high temperature and synergistically constructs a heat-resistant network with triallyl isocyanurate, thereby improving the relaxation resistance and anti-aging performance of the obtained insulating silicone rubber.

[0006] In a specific feasible embodiment, the weight ratio of dicumyl peroxide, triallyl cyanurate, platinum vulcanizing agent, and triallyl isocyanurate in the crosslinking agent is (1.5 - 2.5):1:(0.3 - 0.5):(0.4 - 0.8).

[0007] By adopting the above technical solution, the ratio of dicumyl peroxide, triallyl cyanurate, platinum vulcanizing agent, and triallyl isocyanurate in the crosslinking agent is further defined, thereby improving the crosslinking effect of silicone rubber insulation.

[0008] In a specific feasible embodiment, the structure modifier includes a mixture composed of a terminal hydrogen-containing or side hydrogen-containing silicone oil with a viscosity of 5 - 15 mPa·s and a hydrogen content of 0.1 - 2.0% and a terminal hydrogen-containing or side hydrogen-containing silicone oil with a viscosity of 30 - 50 mPa·s and a hydrogen content of 0.1 - 2.0%.

[0009] By adopting the above technical solution, selecting two silicone oils with different viscosities can play a better lubricating role.

[0010] In a specific feasible embodiment, the silicone rubber matrix includes methyl vinyl silicone rubber.

[0011] In a specific feasible embodiment, the reinforcing agent includes fumed silica.

[0012] In a specific feasible embodiment, the structure control agent includes a mixture composed of methyl disiloxane and tetramethyltetravinylcyclotetrasiloxane.

[0013] By adopting the above technical solution, using the structure control agent composed of methyl disiloxane and tetramethyltetravinylcyclotetrasiloxane makes the molecular chain structure more uniform and controls the chain length.

[0014] In a specific feasible embodiment, the vulcanization aid includes a mixture composed of vinyltriethoxysilane and zinc stearate.

[0015] By adopting the above technical solution, vinyltriethoxysilane can further enhance the crosslinking strength, and zinc stearate complements chemical crosslinking and maintains the elastic recovery rate at high temperatures.

[0016] In a specific feasible embodiment, the antioxidant includes a mixture composed of high molecular weight hindered phenol, phosphite, ultraviolet absorber, and nano cerium oxide.

[0017] By adopting the above technical solution, high molecular weight hindered phenol can resist thermal oxygen aging, phosphite can decompose peroxides, ultraviolet absorber provides ultraviolet protection, and nano cerium oxide synergistically resists oxidation, thus improving the anti-aging performance of silicone rubber insulation.

[0018] In a second aspect, a preparation method of an anti-aging and stress-relaxation-resistant insulating silicone rubber provided by the present application adopts the following technical solutions: A preparation method of an anti-aging and stress-relaxation-resistant insulating silicone rubber includes the following steps: First, stir and disperse a silicone rubber matrix, polyethylene, a reinforcing agent, a structure control agent, a structure modifier, a cross-linking agent, a vulcanization aid, and an antioxidant, and perform vacuum degassing to obtain a mixture; Cure the mixture at 150 °C for 20 min, and then perform secondary vulcanization at 200 °C for 4 h to obtain an anti-aging and stress-relaxation-resistant insulating silicone rubber.

[0019] By adopting the above technical solutions, first stir and disperse a silicone rubber matrix, polyethylene, a reinforcing agent, a structure control agent, a structure modifier, a cross-linking agent, a vulcanization aid, and an antioxidant, perform vacuum degassing, and then carry out heat curing and vulcanization to obtain an anti-aging and stress-relaxation-resistant insulating silicone rubber.

[0020] In summary, the present application includes at least one of the following beneficial technical effects: In the present application, a composite cross-linking agent is used to form a three-dimensional network structure, making the obtained insulating silicone rubber have more stable mechanical properties, which is beneficial to anti-aging and stress relaxation resistance; moreover, there will be no problem of excessive cross-linking and decreased mechanical properties in the silicone rubber insulation; In the present application, the high molecular weight hindered phenol in the antioxidant can resist thermal oxygen aging, the phosphite can decompose peroxides, the ultraviolet absorber provides ultraviolet protection, and nano-ceria synergistically resists oxidation, so the anti-aging performance of the insulating silicone rubber is improved; In the method of the present application, first stir and disperse a silicone rubber matrix, polyethylene, a reinforcing agent, a structure control agent, a structure modifier, a cross-linking agent, a vulcanization aid, and an antioxidant, perform vacuum degassing, and then carry out heat vulcanization to obtain an anti-aging and stress-relaxation-resistant insulating silicone rubber. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram showing the cross-linking of dicumyl peroxide, polyethylene, and triallyl isocyanurate in Example 1. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] The following further elaborates the present application in detail with reference to the embodiments.

[0023] All raw materials in the embodiments can be obtained commercially. Among them, methyl vinyl silicone rubber CAS: 67762-94-1; the high molecular weight hindered phenol is Irganox1010, the phosphite is Irgafos168, the ultraviolet absorber is Tinuvin326; the platinum vulcanizing agent is provided by Ningbo DaRuo Silicone Co., Ltd.

[0024] Example 1 Example 1 provides a preparation method of an anti-aging and relaxation-resistant insulating silicone rubber, comprising the following steps: First, 90 kg of silicone rubber matrix, 5 kg of polyethylene, 30 kg of reinforcing agent, 3.1 kg of structure control agent, 0.9 kg of structure modifier, 2 kg of crosslinking agent, 0.1 kg of vulcanization aid, and 1.5 kg of antioxidant are stirred and dispersed for 40 min, and then degassed under vacuum to obtain a mixture; wherein the silicone rubber matrix is methyl vinyl silicone rubber; the reinforcing agent is fumed silica with a specific surface area of 300 m 2 / g; the structure control agent is a mixture composed of methyldisiloxane and tetramethyltetravinylcyclotetrasiloxane, and the weight ratio of methyldisiloxane to tetramethyltetravinylcyclotetrasiloxane is 1.5:4; the crosslinking agent is a mixture composed of dicumyl peroxide, triallyl cyanurate, platinum vulcanizing agent, and triallyl isocyanurate, and the weight ratio of dicumyl peroxide, triallyl cyanurate, platinum vulcanizing agent, and triallyl isocyanurate is 1:1:0.2:0.2; the structure modifier is a mixture composed of end-hydrogen-containing or side-hydrogen-containing silicone oil with a viscosity of 5-15 mPa·s and a hydrogen content of 0.1-2.0% and end-hydrogen-containing or side-hydrogen-containing silicone oil with a viscosity of 30-50 mPa·s and a hydrogen content of 0.1-2.0%, and the ratio of the two is 1:1; the vulcanization aid is a mixture composed of vinyltriethoxysilane and zinc stearate, and the weight ratio of vinyltriethoxysilane to zinc stearate is 1:2; the antioxidant is a mixture composed of high molecular weight hindered phenol, phosphite, ultraviolet absorber, and nano-cerium oxide, and the weight ratio of high molecular weight hindered phenol, phosphite, ultraviolet absorber, and nano-cerium oxide is 0.75:0.5:0.8:2; The mixture is first cured at 150 °C for 20 min, and then post-cured at 200 °C for 4 h to obtain the anti-aging and relaxation-resistant insulating silicone rubber; the crosslinking principle refers to Figure 1 .

[0025] Example 2 Example 2 provides a preparation method of an anti-aging and relaxation-resistant insulating silicone rubber, comprising the following steps: First, 100 kg of silicone rubber matrix, 6.5 kg of polyethylene, 35 kg of reinforcing agent, 4.5 kg of structure control agent, 1.1 kg of structure modifier, 4 kg of crosslinking agent, 0.5 kg of vulcanization aid, and 2 kg of antioxidant are stirred and dispersed for 40 min, and then degassed under vacuum to obtain a mixture; wherein the silicone rubber matrix is methyl vinyl silicone rubber; the reinforcing agent is fumed silica with a specific surface area of 300 m 2Fumed silica of / g; the structure control agent is a mixture composed of methyldisiloxane and tetramethyltetravinylcyclotetrasiloxane, and the weight ratio of methyldisiloxane to tetramethyltetravinylcyclotetrasiloxane is 1.5:4; the crosslinking agent is a mixture composed of dicumyl peroxide, triallyl cyanurate, platinum vulcanizing agent, and triallyl isocyanurate, and the weight ratio of dicumyl peroxide, triallyl cyanurate, platinum vulcanizing agent, and triallyl isocyanurate is 1:1:0.2:0.2; the structure modifier is a mixture composed of a terminal hydrogen-containing or side hydrogen-containing silicone oil with a viscosity of 5-15 mPa·s and a hydrogen content of 0.1-2.0% and a terminal hydrogen-containing or side hydrogen-containing silicone oil with a viscosity of 30-50 mPa·s and a hydrogen content of 0.1-2.0%, and the ratio of the two is 1:1; the vulcanization aid is a mixture composed of vinyltriethoxysilane and zinc stearate, and the weight ratio of vinyltriethoxysilane to zinc stearate is 1:2; the antioxidant is a mixture composed of high molecular weight hindered phenol, phosphite, ultraviolet absorber, and nano cerium oxide, and the weight ratio of high molecular weight hindered phenol, phosphite, ultraviolet absorber, and nano cerium oxide is 0.75:0.5:0.8:2; The mixture is first cured at 150°C for 20 min, and then secondarily vulcanized at 200°C for 4 h to obtain an anti-aging and relaxation-resistant insulating silicone rubber.

[0026] Example 3 Example 3 provides a preparation method of an anti-aging and relaxation-resistant insulating silicone rubber, including the following steps: First, 110 kg of silicone rubber matrix, 8 kg of polyethylene, 40 kg of reinforcing agent, 6 kg of structure control agent, 1.3 kg of structure modifier, 6 kg of crosslinking agent, 1 kg of vulcanization aid, and 2.5 kg of antioxidant are stirred and dispersed for 40 min, and then vacuum degassed to obtain a mixture; where the silicone rubber matrix is methyl vinyl silicone rubber; the reinforcing agent has a specific surface area of 300 m 2Fumed silica of / g; the structure control agent is a mixture composed of methyldisiloxane and tetramethyltetravinylcyclotetrasiloxane, and the weight ratio of methyldisiloxane to tetramethyltetravinylcyclotetrasiloxane is 1.5:4; the crosslinking agent is a mixture composed of dicumyl peroxide, triallyl cyanurate, platinum vulcanizing agent, and triallyl isocyanurate, and the weight ratio of dicumyl peroxide, triallyl cyanurate, platinum vulcanizing agent, and triallyl isocyanurate is 1:1:0.2:0.2; the structure modifier is a mixture composed of terminal hydrogen-containing or side hydrogen-containing silicone oil with a viscosity of 5-15 mPa·s and a hydrogen content of 0.1-2.0% and terminal hydrogen-containing or side hydrogen-containing silicone oil with a viscosity of 30-50 mPa·s and a hydrogen content of 0.1-2.0%, and the ratio of the two is 1:1; the vulcanization assistant is a mixture composed of vinyltriethoxysilane and zinc stearate, and the weight ratio of vinyltriethoxysilane to zinc stearate is 1:2; the antioxidant is a mixture composed of high molecular weight hindered phenol, phosphite, ultraviolet absorber, and nano cerium oxide, and the weight ratio of high molecular weight hindered phenol, phosphite, ultraviolet absorber, and nano cerium oxide is 0.75:0.5:0.8:2; The mixed material is first cured at 150°C for 20 min, and then secondarily vulcanized at 200°C for 4 h to obtain an anti-aging and relaxation-resistant insulating silicone rubber.

[0027] Example 4 The difference between Example 4 and Example 2 is that the weight ratio of dicumyl peroxide, triallyl cyanurate, platinum vulcanizing agent, and triallyl isocyanurate in the crosslinking agent is 1.5:1:0.3:0.4; the remaining steps are the same as those in Example 2.

[0028] Example 5 The difference between Example 5 and Example 2 is that the weight ratio of dicumyl peroxide, triallyl cyanurate, platinum vulcanizing agent, and triallyl isocyanurate in the crosslinking agent is 2:1:0.4:0.6; the remaining steps are the same as those in Example 2.

[0029] Example 6 The difference between Example 6 and Example 2 is that the weight ratio of dicumyl peroxide, triallyl cyanurate, platinum vulcanizing agent, and triallyl isocyanurate in the crosslinking agent is 2.5:1:0.5:0.8; the remaining steps are the same as those in Example 2.

[0030] Example 7 The difference between Example 7 and Example 2 is that the weight ratio of dicumyl peroxide, triallyl cyanurate, platinum vulcanizing agent, and triallyl isocyanurate in the crosslinking agent is 3:1:0.6:1; the remaining steps are the same as those in Example 2.

[0031] Example 8 Example 8 is different from Example 5 in that the vulcanization aid is vinyltriethoxysilane; the remaining steps are the same as those in Example 5.

[0032] Example 9 Example 9 is different from Example 5 in that the vulcanization aid is zinc stearate; the remaining steps are the same as those in Example 5.

[0033] Example 10 Example 10 is different from Example 5 in that the antioxidant is a mixture composed of high molecular weight hindered phenol and phosphite, and the weight ratio of high molecular weight hindered phenol to phosphite is 0.75:0.5; the remaining steps are the same as those in Example 5.

[0034] Example 11 Example 11 is different from Example 5 in that the antioxidant is a mixture composed of high molecular weight hindered phenol, phosphite and ultraviolet absorber, and the weight ratio of high molecular weight hindered phenol, phosphite and ultraviolet absorber is 0.75:0.5:0.8; the remaining steps are the same as those in Example 5.

[0035] Comparative Example 1 Comparative Example 1 is different from Example 1 in that 90 kg of silicone rubber matrix, 5 kg of polyethylene, 30 kg of reinforcing agent, 3.1 kg of structure control agent, 0.9 kg of structure modifier, 2 kg of platinum vulcanizing agent, 0.1 kg of vulcanization aid, and 1.5 kg of antioxidant are first stirred and dispersed for 40 min and then vacuum degassed to obtain a mixture; the silicone rubber matrix is methyl vinyl silicone rubber; the reinforcing agent is fumed silica with a specific surface area of 300 m 2 / g; the structure modifier is a mixture composed of methyldisiloxane and tetramethyltetravinylcyclotetrasiloxane, and the weight ratio of methyldisiloxane to tetramethyltetravinylcyclotetrasiloxane is 1.5:4; the structure control agent is a mixture composed of end-hydrogenated or side-hydrogenated silicone oil with a viscosity of 5-15 mPa·s and a hydrogen content of 0.1-2.0% and end-hydrogenated or side-hydrogenated silicone oil with a viscosity of 30-50 mPa·s and a hydrogen content of 0.1-2.0%, and the ratio of the two is 1:1; the vulcanization aid is a mixture composed of vinyltriethoxysilane and zinc stearate, and the weight ratio of vinyltriethoxysilane to zinc stearate is 1:2; the antioxidant is a mixture composed of high molecular weight hindered phenol, phosphite, ultraviolet absorber and nano-ceria, and the weight ratio of high molecular weight hindered phenol, phosphite, ultraviolet absorber and nano-ceria is 0.75:0.5:0.8:2; the remaining steps are the same as those in Example 1.

[0036] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that first, 95 kg of silicone rubber matrix, 30 kg of reinforcing agent, 3.1 kg of structure control agent, 0.9 kg of structure modifier, 2 kg of crosslinking agent, 0.1 kg of vulcanization aid, and 1.5 kg of antioxidant are stirred and dispersed for 40 min and then degassed under vacuum to obtain a mixture; the silicone rubber matrix is methyl vinyl silicone rubber; the reinforcing agent is fumed silica with a specific surface area of 300 m 2 / g; the structure control agent is a mixture composed of methyldisiloxane and tetramethyltetravinylcyclotetrasiloxane, and the weight ratio of methyldisiloxane to tetramethyltetravinylcyclotetrasiloxane is 1.5:4; the crosslinking agent is a mixture composed of dicumyl peroxide, triallyl cyanurate, platinum vulcanizing agent, and triallyl isocyanurate, and the weight ratio of dicumyl peroxide, triallyl cyanurate, platinum vulcanizing agent, and triallyl isocyanurate is 1:1:0.2:0.2; the structure modifier is a mixture composed of terminal hydrogen-containing or side hydrogen-containing silicone oil with a viscosity of 5-15 mPa·s and a hydrogen content of 0.1-2.0% and terminal hydrogen-containing or side hydrogen-containing silicone oil with a viscosity of 30-50 mPa·s and a hydrogen content of 0.1-2.0%, and the ratio of the two is 1:1; the vulcanization aid is a mixture composed of vinyltriethoxysilane and zinc stearate, and the weight ratio of vinyltriethoxysilane to zinc stearate is 1:2; the antioxidant is a mixture composed of high molecular weight hindered phenol, phosphite, ultraviolet absorber, and nano-cerium oxide, and the weight ratio of high molecular weight hindered phenol, phosphite, ultraviolet absorber, and nano-cerium oxide is 0.75:0.5:0.8:2; the remaining steps are the same as those in Example 1.

[0037] Relaxation resistance: According to the time-temperature equivalence principle and referring to Test Scheme C in Standard GB / T 9871-2008 "Determination of Aging Properties of Vulcanized Rubber or Thermoplastic Rubber - Tensile Stress Relaxation Test", the specimens are tested. The insulating silicone rubber in each example and comparative example is prepared into the required dumbbell-shaped silicone rubber specimens, and then placed on the gripper of the tensile testing machine. The separation speed of the gripper of the tensile testing machine is adjusted to 50 mm / min. After stretching to a fixed length, the specimen is relaxed, and the strain cycle is quickly repeated 5 times. The initial tensile force (F0) is recorded during the 5th cycle. After the experiment is completed, the specimen is removed from the tensile testing machine and placed in an aging oven at 70°C for accelerated aging. After 24 h, the specimen is taken out and left to stand at standard laboratory temperature for (30±5) min. Subsequently, the specimen is installed on the gripper of the tensile testing machine, and the tensile test is quickly cycled 5 times again, and the tensile force (Ft) during the 5th cycle is recorded. The removed specimen is put back into the aging oven within 2 h, and after an interval of 24 h, the above measurement is repeated. The experimental period is 13 days × 24 h, that is, the duration is 312 h. Calculate the stress retention rate c = Ft / F0 * 100%, where Ft is the tensile force value of the last time within the experimental period. The higher the stress retention rate, the better the relaxation resistance of the product.

[0038] Table 1 Performance test results of insulating silicone rubber

[0039] Combined with Example 1 and Comparative Examples 1-2, the insulating silicone rubber in Example 1 has the best relaxation resistance. It can be seen that when preparing the mixture, a composite crosslinking agent composed of dicumyl peroxide, triallyl cyanurate, platinum vulcanizing agent, and triallyl isocyanurate is selected, and polyethylene is added. After dicumyl peroxide decomposes by heat, it undergoes a hydrogen abstraction reaction with polyethylene molecules. Triallyl isocyanurate combines with the polyethylene molecular chain with free radicals through covalent bonds; since there are three "-CH=CH2" groups in one molecule of triallyl isocyanurate, and each "-CH=CH2" group can combine with the polyethylene molecular chain with free radicals, the same molecule of triallyl isocyanurate can undergo multiple crosslinking reactions with polyethylene molecules, and the connection between molecules after crosslinking is three-dimensional. It is difficult for silicone rubber molecular chains to move in this multi-dimensional complex structure. Therefore, the crosslinked structure formed is a stable three-dimensional network; due to the synergistic effect of the above-mentioned dicumyl peroxide and triallyl isocyanurate, the crosslinking method of silicone rubber molecules and the entanglement between molecules are changed, so that the crosslinking degree increases with the increase of the dosage of dicumyl peroxide, and the "over-crosslinking" state is not likely to occur; triallyl cyanurate releases active free radicals at high temperature and synergistically constructs a heat-resistant network with triallyl isocyanurate. Therefore, the relaxation resistance of the insulating silicone rubber is improved.

[0040] Combined with Examples 1-3, it can be seen that according to the raw material ratios in Examples 1-3, the prepared insulating silicone rubber has good relaxation resistance.

[0041] Combined with Example 2 and Examples 4-7, the insulating silicone rubber in Examples 4-6 has good relaxation resistance. It can be seen that when preparing the mixture, the preferred ratio of dicumyl peroxide, triallyl cyanurate, platinum vulcanizing agent, and triallyl isocyanurate in the crosslinking agent is (1.5-2.5):1:(0.3-0.5):(0.4-0.8), and the performance of the obtained insulating silicone rubber is better.

[0042] Combined with Example 5, Example 8 and Example 9, the insulating silicone rubber in Example 5 has the best relaxation resistance. It can be seen that when preparing the mixture, the preferred vulcanization aid is a mixture composed of vinyltriethoxysilane and zinc stearate, and the obtained insulating silicone rubber has good relaxation resistance.

[0043] Combined with Example 5, Example 10 and Example 11, the relaxation resistance performance of the insulating silicone rubber in Example 5 is the best. It can be seen that when preparing the mixture, the antioxidant is preferably a mixture composed of high molecular weight hindered phenol, phosphite, ultraviolet absorber and nano-cerium oxide, which improves the aging resistance performance of the insulating silicone rubber, and thus further improves the relaxation resistance performance of the insulating silicone rubber.

[0044] This specific embodiment is only an interpretation of the present application, and it is not a limitation of the present application. Those skilled in the art can make modifications to this embodiment without creative contributions according to needs after reading this specification, but as long as it is within the scope of the claims of the present application, it is protected by the patent law.

Claims

1. An anti-aging and relaxation-resistant insulating silicone rubber, characterized in that: The raw materials of the insulating silicone rubber include the following components in parts by weight: 90 - 110 parts of silicone rubber matrix, 5 - 8 parts of polyethylene, 30 - 40 parts of reinforcing agent, 3.1 - 6 parts of structure control agent, 0.9 - 1.3 parts of structure modifier, 2 - 6 parts of crosslinking agent, 0.1 - 1 part of vulcanization assistant, and 1.5 - 2.5 parts of antioxidant; the crosslinking agent includes dicumyl peroxide, triallyl cyanurate, platinum vulcanizing agent, and triallyl isocyanurate.

2. An anti-aging and relaxation-resistant insulating silicone rubber according to claim 1, characterized in that: The weight ratio of dicumyl peroxide, triallyl cyanurate, platinum vulcanizing agent, and triallyl isocyanurate in the crosslinking agent is (1.5 - 2.5):1:(0.3 - 0.5):(0.4 - 0.8).

3. An anti-aging and relaxation-resistant insulating silicone rubber according to claim 2, characterized in that: The structure modifier includes a mixture composed of end - hydrogen - containing or side - hydrogen - containing silicone oil with a viscosity of 5 - 15 mPa·s and a hydrogen content of 0.1 - 2.0% and end - hydrogen - containing or side - hydrogen - containing silicone oil with a viscosity of 30 - 50 mPa·s and a hydrogen content of 0.1 - 2.0%.

4. An anti-aging and relaxation-resistant insulating silicone rubber according to claim 1, characterized in that: The silicone rubber matrix includes methyl vinyl silicone rubber.

5. An anti-aging and relaxation-resistant insulating silicone rubber according to claim 1, characterized in that: The reinforcing agent includes fumed silica.

6. An anti-aging and relaxation-resistant insulating silicone rubber according to claim 1, characterized in that: The structure control agent includes a mixture composed of methyl disiloxane and tetramethyltetravinylcyclotetrasiloxane.

7. An anti-aging and relaxation-resistant insulating silicone rubber according to claim 1, characterized in that: The vulcanization assistant includes a mixture composed of vinyltriethoxysilane and zinc stearate.

8. An anti-aging and relaxation-resistant insulating silicone rubber according to claim 1, characterized in that: The antioxidant includes a mixture composed of high - molecular - weight hindered phenol, phosphite, ultraviolet absorber, and nano - cerium oxide.

9. A preparation method of the anti-aging and relaxation-resistant insulating silicone rubber according to any one of claims 1-8, characterized in that: It includes the following steps: First, stir and disperse the silicone rubber matrix, polyethylene, reinforcing agent, structure control agent, structure modifier, crosslinking agent, vulcanization assistant, and antioxidant, and then conduct vacuum degassing to obtain a mixed material. Cure the mixed material at 150°C for 20 min, and then conduct secondary vulcanization at 200°C for 4 h to obtain the anti - aging and relaxation - resistant insulating silicone rubber.

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