Uv-resistant silicone rubber composition, silicone rubber and method of preparation and use thereof

Abstract

This invention relates to the field of rubber, and discloses an anti-UV silicone rubber composition, silicone rubber, its preparation method, and its applications. The composition comprises methyl vinylsiloxane raw rubber, titanium dioxide, zinc oxide, fumed silica, aluminum hydroxide micron powder, α-alumina, silicone oil, coupling agent, vulcanizing agent, defoamer, and iron oxide. This invention can produce silicone rubber with high surface integrity, excellent mechanical and electrical properties, high heat resistance, strong stability, and excellent resistance to UV aging.

Description

Technical Field

[0001] This invention relates to the field of rubber, specifically to an anti-ultraviolet silicone rubber composition, silicone rubber, its preparation method, and its application. Background Technology

[0002] The main molecular chain of silicone rubber is composed of alternating silicon and oxygen atoms, while the side chains are typically methyl groups or a small number of vinyl groups. Due to its excellent mechanical strength and electrical insulation properties, silicone rubber is widely used in the manufacture of composite insulators and composite jackets for electrical equipment.

[0003] Ultraviolet (UV) light causes surface aging of silicone rubber, roughening its smooth surface and creating physical defects such as voids and cracks. This damages the mechanical strength and electrical insulation properties of silicone rubber, reduces its hydrophobicity, and leads to flashover in insulators and electrical equipment composite jackets, brittle fracture of composite insulator core rods, and other phenomena, shortening the insulator's lifespan. Currently, the normal lifespan of composite insulators is only 10-12 years, far shorter than that of porcelain and glass insulators. Therefore, improving the UV resistance of silicone rubber materials is crucial for extending its service life.

[0004] CN115873412A discloses an electron beam irradiation crosslinked silicone rubber and its preparation process. The electron beam irradiation crosslinked silicone rubber prepared by this technical solution has good insulation and sealing properties; however, its resistance to ultraviolet aging needs to be further improved. Summary of the Invention

[0005] The purpose of this invention is to overcome the problem of poor UV aging resistance of silicone rubber in the prior art, and to provide a silicone rubber composition, silicone rubber, its preparation method and application.

[0006] To achieve the above objectives, a first aspect of the present invention provides a silicone rubber composition comprising methyl vinyl siloxane raw rubber, titanium dioxide, zinc oxide, fumed silica, aluminum hydroxide micron powder, α-alumina, silicone oil, coupling agent, vulcanizing agent, defoamer, and iron oxide. Relative to 100 parts by weight of the methyl vinyl siloxane raw rubber, the content of titanium dioxide is 2.5-7.5 parts by weight, the content of zinc oxide is 3.5-8.5 parts by weight, the content of fumed silica is 31-53 parts by weight, the content of aluminum hydroxide micron powder is 72.5-91 parts by weight, the content of α-alumina is 3.5-8.5 parts by weight, the content of silicone oil is 5-12 parts by weight, the content of coupling agent is 13.5-30 parts by weight, the content of vulcanizing agent is 0.5-1.0 parts by weight, the content of defoamer is 0.2-0.5 parts by weight, and the content of iron oxide is 1.5-2.5 parts by weight.

[0007] The average particle diameter of the titanium dioxide is no greater than 100 nm, the average particle diameter of the zinc oxide is no greater than 100 nm, and the average particle diameter of the α-alumina is no greater than 50 μm.

[0008] The silicone oil contains at least one of hydrosilicone oil, methyl silicone oil, and hydroxyl silicone oil.

[0009] Preferably, the hydroxyl content in the hydroxyl silicone oil is 3wt%-8wt% by mass fraction.

[0010] Preferably, the methyl content in the methyl silicone oil is 95wt%-99wt% by mass fraction.

[0011] Preferably, the hydrogen content in the hydrogen-containing silicone oil is 1.0 wt% to 3 wt% by mass fraction.

[0012] More preferably, in the silicone oil, the mass ratio of the hydrogen-containing silicone oil, the methyl silicone oil, and the hydroxyl silicone oil is 1:1-5:10-20.

[0013] Preferably, the aluminum hydroxide micro powder comprises aluminum hydroxide micro powder I and aluminum hydroxide micro powder II, wherein the average particle diameter of aluminum hydroxide micro powder I is 2.6 μm-4.0 μm, and the average particle diameter of aluminum hydroxide micro powder II is 1.6 μm-2.0 μm.

[0014] Preferably, in the aluminum hydroxide micro powder, the mass ratio of aluminum hydroxide micro powder I to aluminum hydroxide micro powder II is 1:3-5.

[0015] Preferably, the molecular weight of the methyl vinyl siloxane raw rubber is 600,000 to 700,000, and the vinyl content in the methyl vinyl siloxane raw rubber is 0.15 wt% to 0.20 wt% by mass fraction.

[0016] Preferably, the specific surface area of ​​the fumed silica is 180 m². 3 / g-250m 3 / g.

[0017] Preferably, the vulcanizing agent is 1,1-di-tert-butadiene-3,3,5-trimethylcyclohexane.

[0018] Preferably, the defoamer is triethanolamine.

[0019] Preferably, the average diameter of the iron oxide particles is 50μm-150μm.

[0020] A second aspect of the present invention provides a method for preparing silicone rubber, wherein the silicone rubber composition provided in the first aspect of the present invention is processed according to the following steps:

[0021] S1: A portion of methyl vinyl siloxane raw rubber, a portion of silicone oil, and aluminum hydroxide micro powder are subjected to a first kneading treatment to obtain flame-retardant raw rubber; and,

[0022] The remaining methyl vinyl siloxane raw rubber, the remaining silicone oil, and fumed silica are subjected to a second kneading treatment to obtain reinforcing raw rubber.

[0023] S2: The flame-retardant raw rubber, the reinforcing raw rubber, titanium dioxide, zinc oxide, α-alumina, coupling agent, defoamer and iron oxide are subjected to intensive mixing to obtain pre-vulcanized silicone rubber;

[0024] S3: The pre-vulcanized silicone rubber is vulcanized with a vulcanizing agent to obtain silicone rubber;

[0025] In step S1, the mass ratio of the portion of the methyl vinyl siloxane raw rubber undergoing the first kneading treatment to the remaining portion of the methyl vinyl siloxane raw rubber undergoing the second kneading treatment is 1:0.5-0.9; the mass ratio of the portion of the silicone oil undergoing the first kneading treatment to the remaining portion of the silicone oil undergoing the second kneading treatment is 1:2.5-9.

[0026] Preferably, in step S1, the temperature of the first kneading treatment is 140℃-160℃, and the kneading time is 0.5h-2h.

[0027] Preferably, in step S1, the temperature of the second kneading treatment is 140℃-160℃, and the kneading time is 1h-2h.

[0028] Preferably, in step S2, the mixing temperature is 140℃-160℃, the vacuum degree is 0.07MPa-0.1MPa, and the mixing time is 30min-90min.

[0029] Preferably, in step S3, the vulcanization temperature is 140℃-160℃ and the vulcanization time is 10min-30min.

[0030] A third aspect of the present invention provides a silicone rubber made from the silicone rubber composition provided in the first aspect of the present invention, or made from the preparation method provided in the second aspect of the present invention.

[0031] The fourth aspect of the present invention provides the application of the silicone rubber provided in the third aspect of the present invention in the preparation of composite insulators or composite jackets for power equipment.

[0032] The silicone rubber composition provided by the first aspect of the present invention can produce silicone rubber materials with high surface integrity, excellent mechanical and electrical properties, high heat resistance, strong stability, and excellent resistance to ultraviolet aging.

[0033] The preparation method provided by the second aspect of the present invention utilizes the silicone rubber composition provided by the first aspect of the present invention to obtain silicone rubber with high surface integrity, excellent mechanical and electrical properties, high heat resistance, strong stability, excellent UV aging resistance, and long service life. Moreover, the preparation process is simple, the parameters are easy to control, and the obtained silicone rubber has high economic benefits.

[0034] The silicone rubber provided by the third aspect of the present invention has high surface integrity, excellent mechanical and electrical properties, high heat resistance, strong stability, and excellent resistance to ultraviolet aging.

[0035] The fourth aspect of this invention provides composite insulators or composite jackets for power equipment made of silicone rubber with excellent mechanical and electrical properties, high heat resistance, strong stability, excellent resistance to ultraviolet aging, long service life, and high economic benefits. Attached Figure Description

[0036] Figure 1 This is a SEM image of the surface microstructure of silicone rubber L1 provided in Embodiment 1 of the present invention;

[0037] Figure 2 This is a SEM image of the surface microstructure of silicone rubber DL1 provided in Comparative Example 1 of this invention. Detailed Implementation

[0038] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0039] As previously described, a first aspect of the present invention provides a silicone rubber composition comprising methyl vinyl siloxane raw rubber, titanium dioxide, zinc oxide, fumed silica, aluminum hydroxide micron powder, α-alumina, silicone oil, coupling agent, vulcanizing agent, defoamer, and iron oxide. Relative to 100 parts by weight of the methyl vinyl siloxane raw rubber, the content of titanium dioxide is 2.5-7.5 parts by weight, the content of zinc oxide is 3.5-8.5 parts by weight, the content of fumed silica is 31-53 parts by weight, the content of aluminum hydroxide micron powder is 72.5-91 parts by weight, the content of α-alumina is 3.5-8.5 parts by weight, the content of silicone oil is 5-12 parts by weight, the content of coupling agent is 13.5-30 parts by weight, the content of vulcanizing agent is 0.5-1.0 parts by weight, the content of defoamer is 0.2-0.5 parts by weight, and the content of iron oxide is 1.5-2.5 parts by weight.

[0040] The average particle diameter of the titanium dioxide is no greater than 100 nm, the average particle diameter of the zinc oxide is no greater than 100 nm, and the average particle diameter of the α-alumina is no greater than 50 μm.

[0041] The silicone oil contains at least one of hydrosilicone oil, methyl silicone oil, and hydroxyl silicone oil.

[0042] The silicone rubber composition provided by this invention can produce silicone rubber materials with excellent UV aging resistance, high surface integrity, high heat resistance, strong stability, and good mechanical and electrical properties.

[0043] According to a particularly preferred embodiment of the present invention, the titanium dioxide is rutile titanium dioxide, and the average particle diameter of the titanium dioxide is 20nm-50nm. Under these preferred conditions, the silicone rubber obtained has better anti-aging properties, and the raw materials are inexpensive to obtain.

[0044] According to a particularly preferred embodiment of the present invention, the average particle diameter of the zinc oxide is 50nm-100nm. Under this preferred condition, the silicone rubber obtained has better anti-aging properties and the raw materials are inexpensive to obtain.

[0045] According to a preferred embodiment of the present invention, the hydroxyl content in the hydroxyl silicone oil is 3wt%-8wt% by mass fraction.

[0046] According to a preferred embodiment of the present invention, the methyl content in the methyl silicone oil is 95wt%-99wt% by mass fraction.

[0047] According to a preferred embodiment of the present invention, the hydrogen content in the hydrogen-containing silicone oil is 1.0 wt% to 3 wt% by mass fraction.

[0048] According to a more preferred embodiment of the present invention, the mass ratio of the hydrogen-containing silicone oil, the methyl silicone oil, and the hydroxyl silicone oil in the silicone oil is 1:1-5:10-20. Under these preferred conditions, the resulting silicone rubber exhibits superior resistance to ultraviolet aging.

[0049] According to a preferred embodiment of the present invention, the aluminum hydroxide micro powder comprises aluminum hydroxide micro powder I and aluminum hydroxide micro powder II, wherein the average particle diameter of aluminum hydroxide micro powder I is 2.6 μm-4.0 μm, and the average particle diameter of aluminum hydroxide micro powder II is 1.6 μm-2.0 μm.

[0050] According to a preferred embodiment of the present invention, the mass ratio of aluminum hydroxide micropowder I to aluminum hydroxide micropowder II in the aluminum hydroxide micropowder is 1:3-5. The silicone rubber prepared under these preferred conditions exhibits superior UV aging resistance and is inexpensive.

[0051] According to a preferred embodiment of the present invention, the molecular weight of the methyl vinyl siloxane raw rubber is 600,000 to 700,000, and the vinyl content in the methyl vinyl siloxane raw rubber is 0.15 wt% to 0.20 wt% by mass fraction.

[0052] According to a preferred embodiment of the present invention, the specific surface area of ​​the fumed silica is 180 m². 3 / g-250m 3 / g.

[0053] According to a preferred embodiment of the present invention, the vulcanizing agent is 1,1-di-tert-butadiene-3,3,5-trimethylcyclohexane.

[0054] According to a preferred embodiment of the present invention, the defoamer is triethanolamine.

[0055] According to a preferred embodiment of the present invention, the average diameter of the iron oxide particles is 50 μm-150 μm.

[0056] A second aspect of the present invention provides a method for preparing silicone rubber, wherein the silicone rubber composition provided in the first aspect of the present invention is processed according to the following steps:

[0057] S1: A portion of methyl vinyl siloxane raw rubber, a portion of silicone oil, and aluminum hydroxide micro powder are subjected to a first kneading treatment to obtain flame-retardant raw rubber; and,

[0058] The remaining methyl vinyl siloxane raw rubber, the remaining silicone oil, and fumed silica are subjected to a second kneading treatment to obtain reinforcing raw rubber.

[0059] S2: The flame-retardant raw rubber, the reinforcing raw rubber, titanium dioxide, zinc oxide, α-alumina, coupling agent, defoamer and iron oxide are subjected to intensive mixing to obtain pre-vulcanized silicone rubber;

[0060] S3: The pre-vulcanized silicone rubber is vulcanized with a vulcanizing agent to obtain silicone rubber;

[0061] In step S1, the mass ratio of the portion of the methyl vinyl siloxane raw rubber undergoing the first kneading treatment to the remaining portion of the methyl vinyl siloxane raw rubber undergoing the second kneading treatment is 1:0.5-0.9; the mass ratio of the portion of the silicone oil undergoing the first kneading treatment to the remaining portion of the silicone oil undergoing the second kneading treatment is 1:2.5-9.

[0062] The preparation method provided by the present invention utilizes the silicone rubber composition provided in the first aspect of the present invention to prepare silicone rubber. The silicone rubber obtained has an intact surface, excellent mechanical and electrical properties, high heat resistance, strong performance stability, excellent resistance to ultraviolet aging, and long service life.

[0063] According to a preferred embodiment of the present invention, in step S1, the temperature of the first kneading treatment is 140℃-160℃, and the kneading time is 0.5h-2h.

[0064] According to a preferred embodiment of the present invention, in step S1, the temperature of the second kneading treatment is 140℃-160℃, the vacuum degree is 0.07MPa-0.1MPa, and the kneading time is 30min-90min. According to a preferred embodiment of the present invention, in step S2, the temperature of the kneading treatment is 140℃-160℃, the vacuum degree is 0.07MPa-0.1MPa, and the kneading time is 30min-90min.

[0065] According to a preferred embodiment of the present invention, in step S3, the temperature of the vulcanization treatment is 140℃-160℃, and the vulcanization time is 10min-30min.

[0066] According to a preferred embodiment of the present invention, in step S3, before vulcanization, the pre-vulcanized silicone rubber is injected into a mold at an injection pressure of 8 MPa-12 MPa and an injection temperature of 140°C-160°C.

[0067] A third aspect of the present invention provides a silicone rubber made from the silicone rubber composition provided in the first aspect of the present invention, or made from the preparation method provided in the second aspect of the present invention.

[0068] The silicone rubber provided by this invention has high surface integrity, excellent mechanical and electrical properties, high heat resistance, strong stability, and excellent resistance to ultraviolet aging.

[0069] The fourth aspect of this invention provides the application of the silicone rubber provided in the third aspect of this invention in the preparation of composite insulators or composite jackets for power equipment. Composite insulators or composite jackets for power equipment prepared using the silicone rubber provided by this invention exhibit excellent mechanical and electrical properties, high heat resistance, strong stability, excellent resistance to ultraviolet aging, long service life, and high economic benefits.

[0070] The present invention will be described in detail below through examples. In the following examples, unless otherwise specified, all raw materials used are commercially available products.

[0071] Methyl vinyl siloxane raw rubber: brand name GX-172, purchased from Anhui Sibao Organosilicon New Materials Co., Ltd., with main parameters of molecular weight of 660,000 and vinyl content of 0.16wt%.

[0072] Fumed silica: Grade HS-200, purchased from Hoshine Silicon Industry Co., Ltd., with a specific surface area of ​​200m². 3 / g;

[0073] Coupling agent: KH560 coupling agent was selected and purchased from Jiangxi Chenguang New Materials Co., Ltd.

[0074] Vulcanizing agent: 1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane (TMCH), purchased from Jiangsu Qiangsheng Functional Chemical Co., Ltd.

[0075] Defoamer: Triethanolamine was selected and purchased from Jianglong Chemical Co., Ltd.

[0076] Iron oxide: purity 86.0 wt%, average particle diameter 100 μm, purchased from Shanghai Yipin Pigment Co., Ltd.

[0077] Titanium dioxide A: Grade FR-767, purchased from Zhejiang Fangyuan Titanium Dioxide Co., Ltd., with main parameters of rutile type, purity 95.0wt%, and average particle diameter of 50nm;

[0078] Titanium dioxide B: Grade R-298, purchased from Shijiazhuang Shengpeng Chemical Co., Ltd., main parameters: rutile type, purity 97%, average particle diameter 300 nm;

[0079] Zinc oxide A: grade HN-J30, purchased from Hangzhou Hengna New Materials Co., Ltd., with main parameters of purity 99.0wt% and average particle diameter of 30nm;

[0080] Zinc oxide B: The grade is Yaohong Micro-Nano Zinc Oxide, purchased from Hunan Yaohong Nanotechnology Co., Ltd. The main parameters are purity 99.7wt% and average particle diameter 0.44μm;

[0081] Aluminum hydroxide micro powder A: It is composed of aluminum hydroxide micro powder I and aluminum hydroxide micro powder II in a mass ratio of 1:4. The purity of aluminum hydroxide micro powder I is 99.9 wt% and the average particle diameter is 3.0 μm. The purity of aluminum hydroxide micro powder II is 99.9 wt% and the average particle diameter is 1.8 μm.

[0082] Aluminum hydroxide micro powder B: namely, aluminum hydroxide micro powder I with a purity of 99.9 wt% and an average particle diameter of 3.0 μm;

[0083] α-alumina A: Grade AC-30, purchased from Chalco Shandong Co., Ltd., with main parameters: purity 99.0 wt% and average particle diameter 3.0 μm;

[0084] α-alumina B: Grade Xianfeng 200 mesh, purchased from Gongyi Xianfeng Refractory Co., Ltd., with main parameters of purity 99.9wt% and average particle diameter of 75μm;

[0085] Silicone oil A: Composed of hydrogen-containing silicone oil, methyl silicone oil, and hydroxyl silicone oil in a mass ratio of 1:2:15. The hydrogen-containing silicone oil is brand QL-202, purchased from Jiangsu Quanli Chemical Co., Ltd., with a hydrogen content of 1wt%-1.6wt%. The methyl silicone oil is brand QL-201, purchased from Jiangsu Quanli Chemical Co., Ltd., with a methyl content of 98wt%-99wt%. The hydroxyl silicone oil is brand QL-203D, purchased from Jiangsu Quanli Chemical Co., Ltd., with a hydroxyl content of 4wt%-5wt%.

[0086] Silicone oil B: namely, grade QL-202, purchased from Jiangsu Quanli Chemical Co., Ltd., is a hydrogen-containing silicone oil with a hydrogen content of 1wt%-1.6wt%.

[0087] In the following examples, the total mass of the rubber composition in each example is 15 kg.

[0088] Example 1

[0089] The silicone rubber composition is processed according to the following steps:

[0090] S1: A portion of methyl vinyl siloxane raw rubber, a portion of silicone oil, and aluminum hydroxide micro powder are subjected to a first kneading treatment to obtain flame-retardant raw rubber; and,

[0091] The remaining methyl vinyl siloxane raw rubber, the remaining silicone oil, and fumed silica are subjected to a second kneading treatment to obtain reinforcing raw rubber.

[0092] S2: The flame-retardant raw rubber, the reinforcing raw rubber, titanium dioxide, zinc oxide, α-alumina, coupling agent, defoamer and iron oxide are subjected to intensive mixing to obtain pre-vulcanized silicone rubber;

[0093] S3: The pre-vulcanized silicone rubber is vulcanized with a vulcanizing agent to obtain silicone rubber L1;

[0094] In step S1, the mass ratio of the portion of the methyl vinyl siloxane raw rubber undergoing the first kneading treatment to the remaining portion of the methyl vinyl siloxane raw rubber undergoing the second kneading treatment is 3:2; the mass ratio of the portion of the silicone oil undergoing the first kneading treatment to the remaining portion of the silicone oil undergoing the second kneading treatment is 1:5.

[0095] In step S1, the temperature of the first kneading process is 150°C and the kneading time is 1 hour.

[0096] In step S1, the temperature of the second kneading treatment is 150°C, and the kneading time is 1.5 hours.

[0097] In step S2, the mixing temperature is 145°C, the vacuum degree is 0.1 MPa, and the mixing time is 40 min.

[0098] In step S3, the vulcanization temperature is 150°C, the vulcanization pressure is 10 MPa, and the vulcanization time is 15 min.

[0099] The component proportions of the rubber composition are shown in Table 1 below in parts by weight.

[0100] The surface microstructure SEM image of the prepared silicone rubber L1 is shown below. Figure 1 As shown, from Figure 1 It can be seen that the surface structure of silicone rubber L1 is uniform and has excellent density.

[0101] Example 2

[0102] Silicone rubber L2 was prepared according to the method of Example 1, except that the component ratio of the silicone rubber composition was changed, as shown in Table 1.

[0103] Example 3

[0104] Silicone rubber L3 was prepared according to the method of Example 1, except that the composition ratio of the silicone rubber composition was changed, as shown in Table 1.

[0105] Example 4

[0106] Silicone rubber L4 was prepared according to the method of Example 1, except that the composition ratio of the silicone oil was changed, as shown in Table 1.

[0107] Example 5

[0108] Silicone rubber L5 was prepared according to the method in Example 1, except that the composition ratio of aluminum hydroxide micro powder was changed, as shown in Table 1.

[0109] Example 6

[0110] Silicone rubber L6 was prepared according to the method in Example 1, except that the ratio of methyl vinyl siloxane raw rubber and silicone oil in the first kneading treatment and the second kneading treatment was changed. Specifically, the preparation steps are as follows:

[0111] S1: A portion of methyl vinyl siloxane raw rubber, a portion of silicone oil, and aluminum hydroxide micro powder are subjected to a first kneading treatment to obtain flame-retardant raw rubber; and,

[0112] The remaining methyl vinyl siloxane raw rubber, the remaining silicone oil, and fumed silica are subjected to a second kneading treatment to obtain reinforcing raw rubber.

[0113] S2: The flame-retardant raw rubber, the reinforcing raw rubber, titanium dioxide, zinc oxide, α-alumina, coupling agent, defoamer and iron oxide are subjected to intensive mixing to obtain pre-vulcanized silicone rubber;

[0114] S3: The pre-vulcanized silicone rubber is vulcanized with a vulcanizing agent to obtain silicone rubber L1;

[0115] In step S1, the mass ratio of the portion of the methyl vinyl siloxane raw rubber undergoing the first kneading treatment to the remaining portion of the methyl vinyl siloxane raw rubber undergoing the second kneading treatment is 1:1; the mass ratio of the portion of the silicone oil undergoing the first kneading treatment to the remaining portion of the silicone oil undergoing the second kneading treatment is 1:1.

[0116] In step S1, the temperature of the first kneading process is 150°C and the kneading time is 1 hour.

[0117] In step S1, the temperature of the second kneading process is 150°C and the kneading time is 1 hour.

[0118] In step S2, the mixing temperature is 145°C, the vacuum degree is 0.1 MPa, and the mixing time is 40 min.

[0119] In step S3, the vulcanization temperature is 150°C, the vulcanization pressure is 10 MPa, and the vulcanization time is 15 min.

[0120] Comparative Example 1

[0121] Silicone rubber DL1 was prepared according to the method of Example 1, except that the component ratios in the silicone rubber composition were changed, as shown in Table 1.

[0122] The surface microstructure SEM image of the prepared silicone rubber DL1 is shown below. Figure 2 As shown, from Figure 2 It can be seen that the surface particles are unevenly distributed and have poor density.

[0123] Comparative Example 2

[0124] Silicone rubber DL2 was prepared according to the method of Example 1, except that the average particle diameter of titanium dioxide, zinc oxide and α-alumina in the silicone rubber composition was changed, as shown in Table 1.

[0125] Table 1

[0126]

[0127]

[0128] Test Example 1

[0129] The silicone rubber prepared in the examples and comparative examples was cut into silicone rubber samples of 14mm×12mm×2mm. The samples were then tested for electrical and mechanical properties according to the methods in the industry standard "DL / T376-2019 General Technical Conditions for Insulating Materials for Sheaths and Jackets of Polymer Insulators". The test results are shown in Table 2.

[0130] Test Example 2

[0131] The silicone rubber prepared in the examples and comparative examples was cut into 14mm × 12mm × 2mm silicone rubber samples, and then the samples were irradiated at 50°C with a 313UVB light source irradiation intensity of 0.79W / m². 2 The silicone rubber samples were subjected to ultraviolet aging treatment under the following conditions for 500 hours. The performance of the silicone rubber samples after ultraviolet aging treatment was tested according to the method described in Test Example 1. The test results are shown in Table 2 below.

[0132] Table 2

[0133]

[0134] As can be seen from the above comparison, the silicone rubber composition and preparation method provided by the present invention can produce silicone rubber with strong stability and excellent UV resistance.

[0135] Furthermore, as shown in Table 2, the silicone rubber composition and preparation method provided in the embodiments of the present invention produce silicone rubber with excellent properties, and its anti-ultraviolet aging performance is significantly better than that of the silicone rubber prepared in the comparative example.

[0136] Compared with existing technologies, the silicone rubber formulation and preparation process of this invention for resisting ultraviolet aging can produce silicone rubber materials with very good anti-ultraviolet effects. Composite insulators or composite jackets for power equipment made using this material have better performance and service life, and significantly improve the economic performance of the products.

[0137] The silicone rubber composition and preparation method provided in this invention produce silicone rubber with good surface integrity, high heat resistance, strong stability, and excellent mechanical properties, as well as very good resistance to ultraviolet aging. Composite insulators or composite jackets for power equipment made using this silicone rubber material have better performance and longer service life.

[0138] The silicone rubber exhibits low performance degradation and high retention rate under ultraviolet aging. Compared with the silicone rubber provided in the comparative example, the silicone rubber provided in this embodiment of the invention has significantly stronger resistance to ultraviolet aging and a longer service life.

[0139] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A silicone rubber composition, characterized in that, The product comprises methyl vinyl siloxane raw rubber, titanium dioxide, zinc oxide, fumed silica, aluminum hydroxide micron powder, α-alumina, silicone oil, coupling agent, vulcanizing agent, defoamer, and iron oxide. Relative to 100 parts by weight of the methyl vinyl siloxane raw rubber, the content of titanium dioxide is 2.5-7.5 parts by weight, the content of zinc oxide is 3.5-8.5 parts by weight, the content of fumed silica is 31-53 parts by weight, the content of aluminum hydroxide micron powder is 72.5-91 parts by weight, the content of α-alumina is 3.5-8.5 parts by weight, the content of silicone oil is 5-12 parts by weight, the content of coupling agent is 13.5-30 parts by weight, the content of vulcanizing agent is 0.5-1.0 parts by weight, the content of defoamer is 0.2-0.5 parts by weight, and the content of iron oxide is 1.5-2.5 parts by weight. The titanium dioxide is rutile titanium dioxide with an average particle diameter of no more than 100 nm, the zinc oxide has an average particle diameter of no more than 100 nm, and the α-alumina has an average particle diameter of no more than 50 μm. The silicone oil includes: hydrogen-containing silicone oil, methyl silicone oil, and hydroxyl silicone oil; and the mass ratio of the hydrogen-containing silicone oil, the methyl silicone oil, and the hydroxyl silicone oil is 1:1-5:10-20; The aluminum hydroxide micro powder comprises aluminum hydroxide micro powder I and aluminum hydroxide micro powder II. The average particle diameter of aluminum hydroxide micro powder I is 2.6 μm-4.0 μm, and the average particle diameter of aluminum hydroxide micro powder II is 1.6 μm-2.0 μm.

2. The silicone rubber composition according to claim 1, characterized in that, The hydroxyl content in the hydroxyl silicone oil is 3wt%-8wt% by mass fraction. And / or, the methyl content in the methyl silicone oil is 95wt%-99wt% by mass fraction; And / or, the hydrogen content in the hydrogen-containing silicone oil is 1.0wt%-3wt% by mass fraction.

3. The silicone rubber composition according to claim 1 or 2, characterized in that, In the aluminum hydroxide micro powder, the mass ratio of aluminum hydroxide micro powder I to aluminum hydroxide micro powder II is 1:3-5.

4. The silicone rubber composition according to claim 1 or 2, characterized in that, The molecular weight of the methyl vinyl siloxane raw rubber is 600,000-700,000, and the vinyl content in the methyl vinyl siloxane raw rubber is 0.15wt%-0.20wt% by mass fraction. And / or, the specific surface area of ​​the fumed silica is 180 m². 3 / g-250m 3 / g; And / or, the vulcanizing agent is 1,1-di-tert-butadiene-3,3,5-trimethylcyclohexane; And / or, the defoamer is triethanolamine; And / or, the average diameter of the iron oxide particles is 50 μm-150 μm.

5. A method for preparing silicone rubber, characterized in that, The silicone rubber composition according to any one of claims 1-4 is processed according to the following steps: S1: A portion of methyl vinyl siloxane raw rubber, a portion of silicone oil, and aluminum hydroxide micro powder are subjected to a first kneading treatment to obtain flame-retardant raw rubber; and, The remaining methyl vinyl siloxane raw rubber, the remaining silicone oil, and fumed silica are subjected to a second kneading treatment to obtain reinforcing raw rubber. S2: The flame-retardant raw rubber, the reinforcing raw rubber, titanium dioxide, zinc oxide, α-alumina, coupling agent, defoamer and iron oxide are subjected to intensive mixing to obtain pre-vulcanized silicone rubber; S3: The pre-vulcanized silicone rubber is vulcanized with a vulcanizing agent to obtain silicone rubber; In step S1, the mass ratio of the portion of the methyl vinyl siloxane raw rubber undergoing the first kneading treatment to the remaining portion of the methyl vinyl siloxane raw rubber undergoing the second kneading treatment is 1:0.5-0.9; the mass ratio of the portion of the silicone oil undergoing the first kneading treatment to the remaining portion of the silicone oil undergoing the second kneading treatment is 1:2.5-9.

6. The preparation method according to claim 5, characterized in that, In step S1, the temperature of the first kneading treatment is 140℃-160℃, and the kneading time is 0.5h-2h; And / or, in step S1, the temperature of the second kneading treatment is 140℃-160℃, and the kneading time is 1h-2h; And / or, in step S2, the mixing temperature is 140℃-160℃, the vacuum degree is 0.07MPa-0.1MPa, and the mixing time is 30min-90min; And / or, in step S3, the vulcanization temperature is 140℃-160℃ and the vulcanization time is 10min-30min.

7. A silicone rubber, characterized in that, Made from the silicone rubber composition according to any one of claims 1-4, or made by the preparation method according to claim 5 or 6.

8. The application of the silicone rubber according to claim 7 in the preparation of composite insulators or composite jackets for power equipment.

Images