Insulating ultraviolet-resistant EPDM ternary composite material, preparation method and application thereof

Abstract

The application discloses an insulating anti-ultraviolet EPDM rubber composite material and a preparation method and application thereof. The material comprises the following preparation raw materials in parts by weight: 100 parts of EPDM rubber, 10-30 parts of titanium white powder, 30-80 parts of nano insulating filler, 2-5 parts of vulcanizing agent, 1-4 parts of vulcanization accelerator, 0.5-2 parts of antioxidant, 2-5 parts of nano cerium oxide, 0.5-2.5 parts of ultraviolet absorber, and 0.5-2 parts of light stabilizer. The antioxidant comprises a hindered phenol type antioxidant and a phosphite antioxidant. The ultraviolet absorber is a benzotriazole ultraviolet absorber. The vulcanization accelerator comprises triallyl isocyanurate and sulfur. The material has excellent mechanical properties and electrical insulation properties, and can still maintain high stability of mechanical properties and electrical properties under the conditions of thermal oxygen aging and ultraviolet aging. The material is particularly suitable for the field of outdoor cable accessories such as cable joints and terminals which have high reliability requirements.

Description

Technical Field

[0001] This invention relates to the field of rubber technology, and in particular to an insulating and UV-resistant EPDM rubber composite material, its preparation method, and its application. Background Technology

[0002] With the continuous expansion and upgrading of power networks, cable joints, terminals, and other accessories, as key components of power cable lines, directly affect the safety and stability of the entire power grid due to their operational reliability. Ethylene propylene diene monomer (EPDM) rubber, with its excellent electrical insulation properties, weather resistance, ozone aging resistance, and good flexibility, has become the preferred elastomer material for manufacturing cable accessories.

[0003] In long-term outdoor operating environments, especially under ultraviolet radiation from sunlight, cable accessories need to possess good resistance to ultraviolet aging to maintain stable mechanical and electrical properties. Simultaneously, to ensure insulation performance, insulating rubber, such as insulating EPDM, should be selected for the accessory materials. However, existing insulating EPDM materials undergo photo-oxidative degradation of their molecular chains under prolonged ultraviolet irradiation, leading to surface powdering and cracking. Since joints and terminals may be subjected to tensile, bending, and torsional mechanical stresses during operation, the tensile strength and elongation of the material significantly decrease after ultraviolet aging, shortening the service life of cable accessories. Furthermore, ultraviolet aging may also cause a decline in the electrical properties of the material, increasing the risk of power system failures.

[0004] As cable voltage levels gradually increase, developing an EPDM composite material that combines long-term UV aging resistance with durable electrical insulation properties to meet the high reliability requirements of cable accessories such as joints and terminals has become an urgent technical problem to be solved in the industry. Summary of the Invention

[0005] The present invention aims to solve at least one of the aforementioned technical problems existing in the prior art. To this end, the present invention proposes an insulating and UV-resistant EPDM rubber composite material.

[0006] The present invention also proposes a method for preparing the aforementioned insulating and UV-resistant EPDM rubber composite material.

[0007] The present invention also proposes the application of the aforementioned insulating and UV-resistant EPDM rubber composite material.

[0008] The first aspect of this invention relates to an insulating and UV-resistant EPDM rubber composite material, comprising the following raw materials in parts by weight: 100 parts of EPDM rubber 10-30 parts titanium dioxide 30-80 parts of nano-insulating filler 2-5 parts of vulcanizing agent 1-4 parts of vulcanization accelerator Antioxidant 0.5-2 parts, 2-5 parts of nano-cerium oxide, 0.5-2.5 parts of ultraviolet absorber, Light stabilizer 0.5-2 parts; The antioxidants include hindered phenolic antioxidants and phosphite antioxidants; The ultraviolet absorber is a benzotriazole ultraviolet absorber; The vulcanization accelerator includes triallyl isocyanurate and sulfur.

[0009] The insulating and UV-resistant EPDM rubber composite material according to the first aspect of the present invention has at least the following beneficial effects: By rationally proportioning titanium dioxide, nano-insulating fillers, vulcanizing agents and accelerators, antioxidants, nano-cerium oxide, ultraviolet absorbers and light stabilizers, a synergistic system of high-density cross-linked network and multi-level aging protection is formed, which significantly improves the material's resistance to ultraviolet aging and heat aging while ensuring mechanical and electrical insulation properties.

[0010] Specifically, sulfur works together with vulcanizing agents and triallyl isocyanurate to construct a polysulfide bond complex crosslinking network, which significantly improves the crosslinking density and uniformity of the rubber, thereby maintaining high mechanical properties and good electrical insulation properties under heat-oxidation and ultraviolet aging conditions.

[0011] The antioxidants are a combination of hindered phenols and phosphites. In the early stages of vulcanization, the hindered phenol antioxidants, with their large molecular weight and slow migration, have limited inhibition of free radicals, ensuring the full progress of the cross-linking reaction. The phosphite antioxidants decompose vulcanization byproducts and peroxides generated in the early stages of aging, inhibiting the aging reaction at its source. During long-term aging, the hindered phenols continuously capture free radicals, and the phosphites decompose peroxides, thereby effectively slowing down the degradation of the rubber molecular chains.

[0012] Benzotriazole UV absorbers do not interfere with the sulfidation process. They absorb ultraviolet light and convert it into heat energy, thus preventing the generation of photo-initiated free radicals. When combined with light stabilizers, they significantly reduce the rate of photo-oxidative degradation.

[0013] Nano-insulating fillers can improve mechanical and electrical properties; the combination of nano-cerium oxide and titanium dioxide enhances resistance to thermal and photo-oxidative aging. In particular, titanium dioxide acts as a UV shield, further strengthening the material's resistance to thermal and photo-oxidative aging. Specifically, as a UV shielding agent, titanium dioxide effectively mitigates the direct effects of UV light on the rubber backbone, reducing the burden on the antioxidant system.

[0014] In summary, this invention, through multi-component synergistic design, enables the resulting EPDM rubber composite material to possess both excellent mechanical and electrical insulation properties, while maintaining high stability of these properties under thermo-oxidative and UV aging conditions. This material is particularly suitable for outdoor cable accessories with high reliability requirements, such as cable joints and terminals.

[0015] According to some embodiments of the present invention, the EPDM rubber has a Mooney viscosity of ≥60 at ML1+4 / 125°C, an ethylene content of ≥66%, and an ENB content of ≤4.5%.

[0016] The high viscosity and high vinyl content of EPDM rubber are beneficial for improving mechanical properties. However, excessive ENB content may affect heat resistance. By controlling the ENB content, ethylene content, and viscosity of EPDM rubber, the rubber material can possess better mechanical properties, electrical insulation properties, heat aging resistance, and resistance to photo-oxidative degradation.

[0017] According to some preferred embodiments of the present invention, the EPDM rubber has an ENB content of 3.8%-4.5%.

[0018] According to some preferred embodiments of the present invention, the Mooney viscosity of the EPDM rubber at ML1+4 / 125°C is 60-65.

[0019] According to some preferred embodiments of the present invention, the ethylene content of the EPDM rubber is 66%-72%.

[0020] According to some embodiments of the present invention, the titanium dioxide crystal form is rutile.

[0021] According to some embodiments of the present invention, the titanium dioxide is 10-25 parts by weight, for example 10 parts by weight, 15 parts by weight, 20 parts by weight or 25 parts by weight.

[0022] Unless otherwise specified, "parts by weight" of a component indicates the relative mass ratio between the components, rather than specifying a particular unit of mass. When the content of a component is expressed as xy parts by weight, it means that the amount of that component used in the raw materials is xy parts by relative mass. In this embodiment, the amount of titanium dioxide used is 10-25 parts by weight. This value is determined based on the relative proportions of the raw materials. For example, taking 100 parts by weight of EPDM rubber as a reference, the amount of titanium dioxide used is 10-25 parts by weight.

[0023] According to some preferred embodiments of the present invention, the titanium dioxide is 15-25 parts.

[0024] According to some embodiments of the present invention, the titanium dioxide has an average particle size of 0.1-0.5 μm, for example 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm or 0.5 μm.

[0025] According to some embodiments of the present invention, the nano-insulating filler includes at least one of nano-silica, nano-montmorillonite, nano-magnesium oxide, nano-alumina, nano-boron nitride, and nano-silicon nitride.

[0026] According to some embodiments of the present invention, the nano-insulating filler is 30-60 parts, for example 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts or 60 parts.

[0027] According to some preferred embodiments of the present invention, the nano-insulating filler is 40-50 parts.

[0028] According to some embodiments of the present invention, the average particle size of the nano-insulating filler is 10-100 nm, for example 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 55 nm, 60 nm, 65 nm, 70 nm, 75 nm, 80 nm, 85 nm, 90 nm, 95 nm or 100 nm.

[0029] According to some preferred embodiments of the present invention, the average particle size of the nano-insulating filler is 10-50 nm.

[0030] According to some preferred embodiments of the present invention, the nano-insulating filler comprises nano-silica and nano-boron nitride, wherein the mass ratio of the nano-silica to the nano-boron nitride is 1:0.5-2, for example 1:0.5, 1:0.75, 1:1, 1:1.25, 1:1.5, 1:1.75 or 1:2.

[0031] More preferably, the mass ratio of the nano-silica to the nano-boron nitride is 1:0.5-1.5, and even more preferably 1:1-1.5.

[0032] More preferably, the nano-silica has an average particle size of 10-20 nm and a specific surface area of ​​220-380 m². 2 / g.

[0033] More preferably, the average particle size of the boron nitride nanoparticles is 20-50 nm, and the specific surface area is 40-50 m². 2 / g.

[0034] According to some embodiments of the present invention, the vulcanizing agent is a peroxide vulcanizing agent.

[0035] According to some preferred embodiments of the present invention, the vulcanizing agent is selected from at least one of dicumyl peroxide and bis-tert-butyldicumyl peroxide.

[0036] According to some embodiments of the present invention, the vulcanizing agent is 2-4 parts, for example, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, or any value between them. Preferably, the vulcanizing agent is 3-4 parts.

[0037] According to some embodiments of the present invention, the sulfur is insoluble sulfur.

[0038] According to some embodiments of the present invention, the mass ratio of the triallyl isocyanurate to sulfur is 1:0.2-0.5, for example 1:0.2, 1:0.25, 1:0.3, 1:0.35, 1:0.4, 1:0.45 or 1:0.5.

[0039] According to some preferred embodiments of the present invention, the mass ratio of triallyl isocyanurate to sulfur is 1:0.25-0.5, more preferably 1:0.25-0.4.

[0040] According to some embodiments of the present invention, the vulcanization accelerator is 1-3 parts, for example, 1 part, 2 parts, 3 parts or any value between them.

[0041] According to some preferred embodiments of the present invention, the vulcanization accelerator is 1-2 parts.

[0042] According to some embodiments of the present invention, the hindered phenolic antioxidant is selected from at least one of antioxidant 1010, antioxidant 1076, and antioxidant 1024; the phosphite antioxidant is antioxidant 168.

[0043] According to some embodiments of the present invention, the mass ratio of the hindered phenolic antioxidant to the phosphite antioxidant is 1:0.4-0.8, for example 1:0.4, 1:0.45, 1:0.5, 1:0.55, 1:0.6, 1:0.65, 1:0.7, 1:0.75 or 1:0.8.

[0044] According to some preferred embodiments of the present invention, the mass ratio of the hindered phenolic antioxidant to the phosphite antioxidant is 1:0.4-0.75, more preferably 1:0.5-0.7.

[0045] According to some embodiments of the present invention, the total amount of the antioxidant is 0.5-1.5 parts, for example 0.5 parts, 0.8 parts, 1 part, 1.2 parts or 1.5 parts.

[0046] According to some embodiments of the present invention, the nano-cerium oxide is modified with a silane coupling agent.

[0047] According to some embodiments of the present invention, the average particle size of the nano-cerium oxide is 15-30 nm, and the specific surface area is 30-60 m². 2 / g.

[0048] According to some embodiments of the present invention, the nano-cerium oxide is 2-4 parts, for example, 2 parts, 3 parts or 4 parts.

[0049] According to some embodiments of the present invention, the light stabilizer is selected from at least one of HALS944, HALS770, HALS622, HALS119, HALS123, HALS791, and HALS5230.

[0050] According to some preferred embodiments of the present invention, the light stabilizer includes HALS622 and HALS123, wherein the mass ratio of HALS622 to HALS123 is 1:0.4-0.6, for example 1:0.4, 1:0.5 or 1:0.6.

[0051] According to some embodiments of the present invention, the light stabilizer is 0.5-1.5 parts, for example, 0.5 parts, 1 part or 1.5 parts.

[0052] According to some embodiments of the present invention, the ultraviolet absorber is selected from at least one of UV326, UV328, UV329, and UV1164.

[0053] According to some embodiments of the present invention, the ultraviolet absorber is 0.5-2 parts, for example, 0.5 parts, 1 part, 1.5 parts or 2 parts.

[0054] According to some preferred embodiments of the present invention, the ultraviolet absorber is 0.5-1.5 parts.

[0055] According to some embodiments of the present invention, the raw materials for preparation also include other additives.

[0056] According to some preferred embodiments of the present invention, the other additives are selected from at least one of plasticizers, antioxidants, activators, and coupling agents.

[0057] According to some preferred embodiments of the present invention, the other adjuvants are 16-45 parts, for example 16 parts, 17 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts or 45 parts.

[0058] More preferably, the other additives are 17-30 parts.

[0059] More preferably, the plasticizer is selected from at least one of paraffin oil, naphthenic oil, and white oil.

[0060] More preferably, the plasticizer is 12-30 parts, specifically 12 parts, 15 parts, 20 parts, 25 parts, 30 parts or any value between them.

[0061] More preferably, the plasticizer is 15-25 parts.

[0062] More preferably, the antioxidant is selected from at least one of antioxidant RD, antioxidant MB, antioxidant TMQ, antioxidant DMQ, and antioxidant MBZ.

[0063] More preferably, the antioxidant is 1-2 parts, specifically 1 part, 1.2 parts, 1.4 parts, 1.6 parts, 1.8 parts, 2 parts or any value between them.

[0064] More preferably, the activator is selected from at least one of zinc oxide, stearic acid, and zinc stearate.

[0065] More preferably, the active agent is 2-6 parts, specifically 2 parts, 3 parts, 4 parts, 5 parts, 6 parts or any value between them.

[0066] More preferably, the active agent is 4-6 parts.

[0067] More preferably, the coupling agent is selected from at least one of bis-(γ-triethoxysilylpropyl)tetrasulfide and vinyltris(β-methoxyethoxy)silane.

[0068] More preferably, the coupling agent is 1-3 parts, for example, 1 part, 2 parts or 3 parts.

[0069] More preferably, the additives include: 15-25 parts plasticizer, 1-2 parts antioxidant, 2-6 parts activator, and 1-3 parts coupling agent.

[0070] The second aspect of the present invention relates to a method for preparing the aforementioned insulating and UV-resistant EPDM rubber composite material, comprising: mixing the EPDM rubber, titanium dioxide, nano-insulating filler, nano-cerium oxide, antioxidant, UV absorber, light stabilizer, and optionally plasticizer, antioxidant, activator, and coupling agent under heating conditions for a first stage of mixing, followed by cooling, and then adding the vulcanizing agent and vulcanization accelerator for a second stage of mixing.

[0071] The above preparation method is used to prepare the above-mentioned insulating and UV-resistant EPDM rubber composite material. Therefore, it has at least all the beneficial effects of the above-mentioned embodiments of the insulating and UV-resistant EPDM rubber composite material. The preparation process of this method is simple and easy to produce and apply.

[0072] Mixing is usually carried out using an internal mixer, which is a plasticizing system consisting of two relatively rotating rotors, a mixing chamber, and an upper jack. The temperature can be adjusted. In the plasticizing system, the material is subjected to repeated shearing, tearing, stirring, and friction under the pressure of the upper jack and the friction of the two relatively rotating rotors, which increases the plasticity of the material and makes it more evenly dispersed.

[0073] According to some embodiments of the present invention, the heating temperature is 180-210°C.

[0074] According to some embodiments of the present invention, the first mixing step includes: performing a first mixing of the EPDM rubber at 180-210°C, adding the nano-cerium oxide, antioxidant, ultraviolet absorber, light stabilizer, and optionally anti-aging agent, activator and coupling agent, performing a second mixing, adding the titanium dioxide and nano-insulating filler, and optionally plasticizer, and performing a third mixing.

[0075] According to some embodiments of the present invention, the first mixing time is 1-2 minutes.

[0076] According to some embodiments of the present invention, the second mixing time is 2-5 minutes.

[0077] According to some embodiments of the present invention, the third mixing is either a one-step mixing or a multi-step mixing. Multi-step mixing refers to adding the raw materials in stages, which can be two or more stages. The amount of material added in each stage can be the same or different, and the composition of the raw materials added in each stage can be the same or different.

[0078] According to some embodiments of the present invention, the third mixing time is 5-10 minutes.

[0079] According to some embodiments of the present invention, the temperature of the second mixing stage is 50-70°C.

[0080] According to some embodiments of the present invention, the second mixing time is 2-5 minutes.

[0081] According to some embodiments of the present invention, after cooling and before the second stage of mixing, the process further includes: pre-mixing the rubber compound obtained from the first stage of mixing.

[0082] According to some embodiments of the present invention, the premixing time is 1-2 minutes.

[0083] The third aspect of the present invention relates to the application of the aforementioned insulating and UV-resistant EPDM rubber composite material in the preparation of cable accessories.

[0084] Given the advantages of the aforementioned insulating and UV-resistant EPDM rubber composite material, it is possible to improve the performance and service life of cable accessories made using this insulating and UV-resistant EPDM rubber composite material.

[0085] According to some embodiments of the present invention, the cable accessory includes a connector or a terminal.

[0086] In this article, "multiple times" means more than twice, and "more than" includes the number itself. For example, "more than twice" includes two times.

[0087] The numerical ranges involved all include endpoint values ​​and cover any subranges within that range, such as the ranges obtained by arbitrarily combining the specifically listed numerical values.

[0088] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Detailed Implementation

[0089] The embodiments of the present invention are described in detail below. These embodiments are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0090] The raw materials used in the following examples and comparative examples are described below: Ethylene propylene diene monomer (EPDM) rubber: Shaanxi Yanchang Petroleum Yan'an Energy and Chemical Co., Ltd., grade EPDM-Y-06H2D4, Mooney viscosity ML (1+4, 125℃) is 64.9, ethylene content is 71%, and ENB content is 4.2%; Arlanxnetech, grade 5467C, ML (1+4, 125℃) is 52.0, ethylene content is 58%, and ENB content is 4.5%; China National Petroleum Corporation Jilin Petrochemical Branch, grade J-4045, Mooney viscosity ML (1+4, 100℃) is 45.0, ethylene content is 52.9%, and ENB content is 7.6%.

[0091] Nano-cerium oxide: Hangzhou Hengge Nanotechnology Co., Ltd., brand name HN-Ce01GH, silane coupling agent K550 modified nano-cerium oxide, cerium oxide content ≥99.99%, average particle size 30nm, specific surface area 30-60m² 2 / g.

[0092] Titanium dioxide: Shandong Dongjia Group Co., Ltd., grade SR-2377, TiO2 content ≥93%, rutile crystal content ≥98%, average particle size 0.3μm, oil absorption value 16-20g / 100g.

[0093] Antioxidant: Tianjin Lianlong New Materials Co., Ltd., brand name RIANOX ®1010, a macromolecular multi-functional hindered phenolic antioxidant; Suqian Liansheng Group, brand name AO 168, a phosphite antioxidant.

[0094] UV absorber: Tianjin Lianlong New Materials Co., Ltd., brand name RIASORB ® UV-329, a benzotriazole ultraviolet absorber; Cytec Corporation, USA, brand name UV-531.

[0095] Light stabilizers: Suqian Liansheng Group, brand name HALS 622, a polymeric high molecular weight, highly efficient hindered amine light stabilizer; brand name HALS 123, a liquid hindered amine light stabilizer.

[0096] Insoluble sulfur: Jiangsu Ruiba New Material Technology Co., Ltd., grade IS-75GE.

[0097] Nano-silica: average particle size 10-20nm, purity ≥99.9%, specific surface area 220-380m² 2 / g.

[0098] Nano-sized boron nitride: average particle size 20-50 nm, purity ≥99.9%, specific surface area 40-50 m² 2 / g.

[0099] Internal mixer: Manufactured by Guangdong Lina Industrial Co., Ltd., model LN-LT-1L.

[0100] Unless otherwise specified, all raw materials or equipment mentioned are commercially available and readily available.

[0101] Example 1 This embodiment prepares an insulating and UV-resistant EPDM rubber composite material, comprising the following raw materials: 100 kg EPDM rubber (EPDM-Y-06H2D4), 25 kg titanium dioxide (SR-2377), 0.8 kg antioxidant (RIANOX®1010), 3 kg silane coupling agent modified nano-cerium oxide, 0.5 kg antioxidant (AO 168), 1.6 kg UV absorber (UV-329), 1 kg light stabilizer (HALS 622), 0.5 kg light stabilizer (HALS 123), 20 kg nano-silica, 25 kg nano-boron nitride, 15 kg paraffin oil, 1 kg antioxidant DMQ, 5 kg zinc oxide (purity ≥95.5 wt%), 1 kg stearic acid, 2 kg silane coupling agent, 4 kg vulcanizing agent DCP, 1.5 kg vulcanization accelerator (TAIC, triallyl isocyanurate), and 0.5 kg insoluble sulfur.

[0102] The preparation steps are as follows: (1) Heat the internal mixer to 180-210℃ and put in 100kg of EPDM-Y-06H2D4 for plasticizing for 1min; (2) Add 5kg zinc oxide (purity above 95.5wt%), 1kg stearic acid, 2kg silane coupling agent, 1kg antioxidant DMQ, 0.8kg antioxidant (RIANOX® 1010), 0.5kg antioxidant (AO 168), 3kg silane coupling agent modified nano cerium oxide, 1.6kg ultraviolet absorber (UV-329), 1kg light stabilizer (HALS 622), and 0.5kg light stabilizer (HALS 123) and mix for 2 minutes. After mixing evenly, proceed to the following steps. (3) Add 7.5kg paraffin oil, 12.5kg titanium dioxide (SR-2377), 10kg nano silica, and 12.5kg nano boron nitride and mix for 3 minutes. After mixing evenly, proceed to the following steps. (4) Add 7.5kg paraffin oil, 12.5kg titanium dioxide (SR-2377), 10kg nano silica, and 12.5kg nano boron nitride and mix for 3 minutes. After mixing evenly, proceed to the following steps. (5) Remove the mixed rubber blocks from the internal mixer; (6) Cool the internal mixer to 50-70℃, and put the rubber block prepared in the above steps into the internal mixer and mix for 1 minute; (7) Add 4 kg of vulcanizing agent DCP, 1.5 kg of vulcanization accelerator (TAIC) and 0.5 kg of insoluble sulfur and mix for 3 min; (8) Take the mixed rubber block out of the internal mixer to obtain the insulating and UV-resistant EPDM rubber composite material.

[0103] Example 2 This embodiment prepares an insulating and UV-resistant EPDM rubber composite material, comprising the following raw materials: 100 kg EPDM rubber (5467C), 25 kg titanium dioxide (SR-2377), 0.8 kg antioxidant (RIANOX® 1010), 0.5 kg antioxidant (AO 168), 3 kg silane coupling agent modified nano-cerium oxide, 1.6 kg UV absorber (UV-329), 1 kg light stabilizer (HALS 622), 0.5 kg light stabilizer (HALS 123), 20 kg nano-silica, 25 kg nano-boron nitride, 15 kg paraffin oil, 1 kg antioxidant DMQ, 5 kg zinc oxide (purity above 95.5 wt%), 1 kg stearic acid, 2 kg silane coupling agent, 4 kg vulcanizing agent DCP, 1.5 kg vulcanization accelerator (TAIC, triallyl isocyanurate), and 0.5 kg insoluble sulfur.

[0104] The preparation steps are as follows: (1) Heat the internal mixer to 180-210℃ and put in 100kg of EPDM rubber (5467C) for plasticizing for 1min; (2) Add 5kg zinc oxide (purity above 95.5wt%), 1kg stearic acid, 2kg silane coupling agent, 1kg antioxidant DMQ, 0.8kg antioxidant (RIANOX® 1010), 0.5kg antioxidant (AO 168), 3kg silane coupling agent modified nano cerium oxide, 1.6kg ultraviolet absorber (UV-329), 1kg light stabilizer (HALS 622), and 0.5kg light stabilizer (HALS 123) and mix for 2 minutes. After mixing evenly, proceed to the following steps. (3) Add 7.5kg paraffin oil, 12.5kg titanium dioxide (SR-2377), 10kg nano silica, and 12.5kg nano boron nitride and mix for 3 minutes. After mixing evenly, proceed to the following steps. (4) Add 7.5kg paraffin oil, 12.5kg titanium dioxide (SR-2377), 10kg nano silica, and 12.5kg nano boron nitride and mix for 3 minutes. After mixing evenly, proceed to the following steps. (5) Remove the mixed rubber blocks from the internal mixer; (6) Cool the internal mixer to 50-70℃, and put the rubber block prepared in the above steps into the internal mixer and mix for 1 minute; (7) Add 4 kg of vulcanizing agent DCP, 1.5 kg of vulcanization accelerator (TAIC) and 0.5 kg of insoluble sulfur and mix for 3 min; (8) Take the mixed rubber block out of the internal mixer to obtain the insulating and UV-resistant EPDM rubber composite material.

[0105] Example 3 This embodiment prepares an insulating and UV-resistant EPDM rubber composite material, comprising the following raw materials: 100 kg EPDM rubber (J-4045), 25 kg titanium dioxide (SR-2377), 0.8 kg antioxidant (RIANOX® 1010), 0.5 kg antioxidant (AO 168), 3 kg silane coupling agent modified nano-cerium oxide, 1.6 kg UV absorber (UV-329), 1 kg light stabilizer (HALS 622), 0.5 kg light stabilizer (HALS 123), 20 kg nano-silica, 25 kg nano-boron nitride, 15 kg paraffin oil, 1 kg antioxidant DMQ, 5 kg zinc oxide (purity ≥ 95.5 wt%), 1 kg stearic acid, 2 kg silane coupling agent, 4 kg vulcanizing agent DCP, 1.5 kg vulcanization accelerator (TAIC, triallyl isocyanurate), and 0.5 kg insoluble sulfur.

[0106] The preparation steps are as follows: (1) Heat the internal mixer to 180-210℃ and put in 100kg of EPDM rubber (J-4045) for plasticizing for 1min; (2) Add 5kg zinc oxide (purity above 95.5wt%), 1kg stearic acid, 2kg silane coupling agent, 1kg antioxidant DMQ, 0.8kg antioxidant (RIANOX® 1010), 0.5kg antioxidant (AO 168), 3kg silane coupling agent modified nano cerium oxide, 1.6kg ultraviolet absorber (UV-329), 1kg light stabilizer (HALS 622), and 0.5kg light stabilizer (HALS 123) and mix for 2 minutes. After mixing evenly, proceed to the following steps. (3) Add 7.5kg paraffin oil, 12.5kg titanium dioxide (SR-2377), 10kg nano silica, and 12.5kg nano boron nitride and mix for 3 minutes. After mixing evenly, proceed to the following steps. (4) Add 7.5kg paraffin oil, 12.5kg titanium dioxide (SR-2377), 10kg nano silica, and 12.5kg nano boron nitride and mix for 3 minutes. After mixing evenly, proceed to the following steps. (5) Remove the mixed rubber blocks from the internal mixer; (6) Cool the internal mixer to 50-70℃, and put the rubber block prepared in the above steps into the internal mixer and mix for 1 minute; (7) Add 4 kg of vulcanizing agent DCP, 1.5 kg of vulcanization accelerator (TAIC) and 0.5 kg of insoluble sulfur and mix for 3 min; (8) Take the mixed rubber block out of the internal mixer to obtain the insulating and UV-resistant EPDM rubber composite material.

[0107] Example 4 This embodiment prepares an insulating and UV-resistant EPDM rubber composite material, comprising the following raw materials: 100 kg EPDM rubber (EPDM-Y-06H2D4), 25 kg titanium dioxide (SR-2377), 0.8 kg antioxidant (RIANOX®1010), 0.5 kg antioxidant (AO 168), 3 kg silane coupling agent modified nano-cerium oxide, 1.6 kg UV absorber (UV-329), 1 kg light stabilizer (HALS 622), 0.5 kg light stabilizer (HALS 123), 30 kg nano-silica, 15 kg nano-boron nitride, 15 kg paraffin oil, 1 kg antioxidant DMQ, 5 kg zinc oxide (purity above 95.5 wt%), 1 kg stearic acid, 2 kg silane coupling agent, 4 kg vulcanizing agent DCP, 1.5 kg vulcanization accelerator (TAIC, triallyl isocyanurate), and 0.5 kg insoluble sulfur.

[0108] The preparation steps are the same as in Example 1.

[0109] Comparative Example 1 This comparative example prepared an insulating and UV-resistant EPDM rubber composite material, comprising the following raw materials: 100 kg EPDM rubber (EPDM-Y-06H2D4), 25 kg titanium dioxide (SR-2377), 0.5 kg antioxidant (AO 168), 3 kg silane coupling agent modified nano-cerium oxide, 1.6 kg UV absorber (UV-329), 1 kg light stabilizer (HALS 622), 0.5 kg light stabilizer (HALS 123), 20 kg nano-silica, 25 kg nano-boron nitride, 15 kg paraffin oil, 1 kg antioxidant DMQ, 5 kg zinc oxide (purity ≥ 95.5 wt%), 1 kg stearic acid, 2 kg silane coupling agent, 4 kg vulcanizing agent DCP, 1.5 kg vulcanization accelerator (TAIC, triallyl isocyanurate), and 0.5 kg insoluble sulfur.

[0110] The preparation steps are as follows: (1) Heat the internal mixer to 180-210℃ and put in 100kg of EPDM-Y-06H2D4 for plasticizing for 1min; (2) Add 5kg zinc oxide (purity above 95.5wt%), 1kg stearic acid, 2kg silane coupling agent, 1kg antioxidant DMQ, 1.3kg antioxidant (AO 168), 3kg silane coupling agent modified nano cerium oxide, 1.6kg ultraviolet absorber (UV-329), 1kg light stabilizer (HALS 622), and 0.5kg light stabilizer (HALS 123) and mix for 2 minutes. After mixing evenly, proceed to the following steps. (3) Add 7.5kg paraffin oil, 12.5kg titanium dioxide (SR-2377), 10kg nano silica, and 12.5kg nano boron nitride and mix for 3 minutes. After mixing evenly, proceed to the following steps. (4) Add 7.5kg paraffin oil, 12.5kg titanium dioxide (SR-2377), 10kg nano silica, and 12.5kg nano boron nitride and mix for 3 minutes. After mixing evenly, proceed to the following steps. (5) Remove the mixed rubber blocks from the internal mixer; (6) Cool the internal mixer to 50-70℃, and put the rubber block prepared in the above steps into the internal mixer and mix for 1 minute; (7) Add 4 kg of vulcanizing agent DCP, 1.5 kg of vulcanization accelerator (TAIC) and 0.5 kg of insoluble sulfur and mix for 3 min; (8) Take the mixed rubber block out of the internal mixer to obtain the insulating and UV-resistant EPDM rubber composite material.

[0111] Comparative Example 2 This comparative example prepared an insulating and UV-resistant EPDM rubber composite material, comprising the following raw materials: 100 kg EPDM rubber (EPDM-Y-06H2D4), 25 kg titanium dioxide (SR-2377), 1.3 kg antioxidant (RIANOX®1010), 3 kg silane coupling agent modified nano-cerium oxide, 1.6 kg UV absorber (UV-329), 1 kg light stabilizer (HALS622), 0.5 kg light stabilizer (HALS 123), 20 kg nano-silica, 25 kg nano-boron nitride, 15 kg paraffin oil, 1 kg antioxidant DMQ, 5 kg zinc oxide (purity ≥95.5 wt%), 1 kg stearic acid, 2 kg silane coupling agent, 4 kg vulcanizing agent DCP, 1.5 kg vulcanization accelerator (TAIC, triallyl isocyanurate), and 0.5 kg insoluble sulfur.

[0112] The preparation steps are as follows: (1) Heat the internal mixer to 180-210℃ and put in 100kg of EPDM-Y-06H2D4 for plasticizing for 1min; (2) Add 5kg zinc oxide (purity above 95.5wt%), 1kg stearic acid, 2kg silane coupling agent, 1kg antioxidant DMQ, 0.8kg antioxidant (RIANOX® 1010), 3kg silane coupling agent modified nano cerium oxide, 1.6kg ultraviolet absorber (UV-329), 1kg light stabilizer (HALS 622), and 0.5kg light stabilizer (HALS 123) and mix for 2 minutes. After mixing evenly, proceed to the following steps. (3) Add 7.5kg paraffin oil, 12.5kg titanium dioxide (SR-2377), 10kg nano silica, and 12.5kg nano boron nitride and mix for 3 minutes. After mixing evenly, proceed to the following steps. (4) Add 7.5kg paraffin oil, 12.5kg titanium dioxide (SR-2377), 10kg nano silica, and 12.5kg nano boron nitride and mix for 3 minutes. After mixing evenly, proceed to the following steps. (5) Remove the mixed rubber blocks from the internal mixer; (6) Cool the internal mixer to 50-70℃, and put the rubber block prepared in the above steps into the internal mixer and mix for 1 minute; (7) Add 4 kg of vulcanizing agent DCP, 1.5 kg of vulcanization accelerator (TAIC) and 0.5 kg of insoluble sulfur and mix for 3 min; (8) Take the mixed rubber block out of the internal mixer to obtain the insulating and UV-resistant EPDM rubber composite material.

[0113] Comparative Example 3 This comparative example prepared an insulating and UV-resistant EPDM rubber composite material, comprising the following raw materials: 100 kg EPDM rubber (EPDM-Y-06H2D4), 25 kg titanium dioxide (SR-2377), 0.8 kg antioxidant (RIANOX®1010), 0.5 kg antioxidant (AO 168), 3 kg silane coupling agent modified nano-cerium oxide, 1.6 kg UV absorber (UV-329), 20 kg nano-silica, 25 kg nano-boron nitride, 15 kg paraffin oil, 1 kg antioxidant DMQ, 5 kg zinc oxide (purity ≥95.5 wt%), 1 kg stearic acid, 2 kg silane coupling agent, 4 kg vulcanizing agent DCP, 1.5 kg vulcanization accelerator (TAIC, triallyl isocyanurate), and 0.5 kg insoluble sulfur.

[0114] The preparation steps are the same as in Example 1, except that the light stabilizers HALS 622 and HALS123 were not added in step (2).

[0115] Comparative Example 4 This comparative example prepared an insulating and UV-resistant EPDM rubber composite material, comprising the following raw materials: 100 kg EPDM rubber (EPDM-Y-06H2D4), 25 kg titanium dioxide (SR-2377), 0.8 kg antioxidant (RIANOX®1010), 0.5 kg antioxidant (AO 168), 3 kg silane coupling agent modified nano-cerium oxide, 1.6 kg UV absorber (UV-531), 1 kg light stabilizer (HALS 622), 0.5 kg light stabilizer (HALS 123), 20 kg nano-silica, 25 kg nano-boron nitride, 15 kg paraffin oil, 1 kg antioxidant DMQ, 5 kg zinc oxide (purity ≥95.5 wt%), 1 kg stearic acid, 2 kg silane coupling agent, 4 kg vulcanizing agent DCP, 1.5 kg vulcanization accelerator (TAIC, triallyl isocyanurate), and 0.5 kg insoluble sulfur.

[0116] The preparation steps are the same as in Example 1, except that the UV absorber in step (2) is UV-531.

[0117] Comparative Example 5 This comparative example prepared an insulating and UV-resistant EPDM rubber composite material, comprising the following raw materials: 100 kg EPDM rubber (EPDM-Y-06H2D4), 25 kg titanium dioxide (SR-2377), 0.8 kg antioxidant (RIANOX®1010), 0.5 kg antioxidant (AO 168), 1.6 kg UV absorber (UV-329), 1 kg light stabilizer (HALS 622), 0.5 kg light stabilizer (HALS 123), 20 kg nano silica, 25 kg nano boron nitride, 15 kg paraffin oil, 1 kg antioxidant DMQ, 5 kg zinc oxide (purity above 95.5 wt%), 1 kg stearic acid, 2 kg silane coupling agent, 4 kg vulcanizing agent DCP, 1.5 kg vulcanization accelerator (TAIC, triallyl isocyanurate), and 0.5 kg insoluble sulfur.

[0118] The preparation steps are the same as in Example 1, except that no silane coupling agent was added to modify the nano-cerium oxide in step (2).

[0119] Comparative Example 6 This embodiment prepares an insulating and UV-resistant EPDM rubber composite material, comprising the following raw materials: 100 kg EPDM rubber (EPDM-Y-06H2D4), 25 kg titanium dioxide (SR-2377), 0.8 kg antioxidant (RIANOX®1010), 0.5 kg antioxidant (AO 168), 3 kg silane coupling agent modified nano-cerium oxide, 1.6 kg UV absorber (UV-329), 1 kg light stabilizer (HALS 622), 0.5 kg light stabilizer (HALS 123), 20 kg nano-silica, 25 kg nano-boron nitride, 15 kg paraffin oil, 1 kg antioxidant DMQ, 5 kg zinc oxide (purity above 95.5 wt%), 1 kg stearic acid, 2 kg silane coupling agent, 4 kg yellowing resistant curing accelerator (zinc dialkyl dithiophosphate), and 0.5 kg insoluble sulfur.

[0120] The preparation steps are as follows: (1) Heat the internal mixer to 180-210℃ and put in 100kg of EPDM-Y-06H2D4 for plasticizing for 1min; (2) Add 5kg zinc oxide (purity above 95.5wt%), 1kg stearic acid, 2kg silane coupling agent, 1kg antioxidant DMQ, 0.8kg antioxidant (RIANOX® 1010), 0.5kg antioxidant (AO 168), 3kg silane coupling agent modified nano cerium oxide, 1.6kg ultraviolet absorber (UV-329), 1kg light stabilizer (HALS 622), and 0.5kg light stabilizer (HALS 123) and mix for 2 minutes. After mixing evenly, proceed to the following steps. (3) Add 7.5kg paraffin oil, 12.5kg titanium dioxide (SR-2377), 10kg nano silica, and 12.5kg nano boron nitride and mix for 3 minutes. After mixing evenly, proceed to the following steps. (4) Add 7.5kg paraffin oil, 12.5kg titanium dioxide (SR-2377), 10kg nano silica, and 12.5kg nano boron nitride and mix for 3 minutes. After mixing evenly, proceed to the following steps. (5) Remove the mixed rubber blocks from the internal mixer; (6) Cool the internal mixer to 50-70℃, and put the rubber block prepared in the above steps into the internal mixer and mix for 1 minute; (7) Add 4 kg of yellowing-resistant sulfurization accelerator (zinc dialkyl dithiophosphate) and 0.5 kg of insoluble sulfur and mix for 3 min; (8) Take the mixed rubber block out of the internal mixer to obtain the insulating and UV-resistant EPDM rubber composite material.

[0121] Comparative Example 7 This embodiment prepares an insulating and UV-resistant EPDM rubber composite material, comprising the following raw materials: 100 kg EPDM rubber (EPDM-Y-06H2D4), 0.8 kg antioxidant (RIANOX® 1010), 0.5 kg antioxidant (AO168), 3 kg silane coupling agent modified nano-cerium oxide, 1.6 kg UV absorber (UV-329), 1 kg light stabilizer (HALS622), 0.5 kg light stabilizer (HALS 123), 20 kg nano-silica, 25 kg nano-boron nitride, 15 kg paraffin oil, 1 kg antioxidant DMQ, 5 kg zinc oxide (purity ≥ 95.5 wt%), 1 kg stearic acid, 2 kg silane coupling agent, 4 kg vulcanizing agent DCP, 1.5 kg vulcanization accelerator (TAIC, triallyl isocyanurate), and 0.5 kg insoluble sulfur.

[0122] The preparation steps are as follows: (1) Heat the internal mixer to 180-210℃ and put in 100kg of EPDM-Y-06H2D4 for plasticizing for 1min; (2) Add 5kg zinc oxide (purity above 95.5wt%), 1kg stearic acid, 2kg silane coupling agent, 1kg antioxidant DMQ, 0.8kg antioxidant (RIANOX® 1010), 0.5kg antioxidant (AO 168), 3kg silane coupling agent modified nano cerium oxide, 1.6kg ultraviolet absorber (UV-329), 1kg light stabilizer (HALS 622), and 0.5kg light stabilizer (HALS 123) and mix for 2 minutes. After mixing evenly, proceed to the following steps. (3) Add 7.5kg paraffin oil, 10kg nano silica, and 12.5kg nano boron nitride and mix for 3 minutes. After mixing evenly, proceed to the following steps; (4) Add 7.5kg paraffin oil, 10kg nano silica, and 12.5kg nano boron nitride and mix for 3 minutes. After mixing evenly, proceed to the following steps. (5) Remove the mixed rubber blocks from the internal mixer; (6) Cool the internal mixer to 50-70℃, and put the rubber block prepared in the above steps into the internal mixer and mix for 1 minute; (7) Add 4 kg of vulcanizing agent DCP, 1.5 kg of vulcanization accelerator (TAIC) and 0.5 kg of insoluble sulfur and mix for 3 min; (8) Take the mixed rubber block out of the internal mixer to obtain the insulating and UV-resistant EPDM rubber composite material.

[0123] Comparative Example 8 This comparative example prepared an insulating and UV-resistant EPDM rubber composite material, comprising the following raw materials: 100 kg EPDM rubber (EPDM-Y-06H2D4), 25 kg titanium dioxide (SR-2377), 0.8 kg antioxidant (RIANOX®1010), 3 kg silane coupling agent modified nano-cerium oxide, 0.5 kg antioxidant (AO 168), 1.6 kg UV absorber (UV-329), 1 kg light stabilizer (HALS 622), 0.5 kg light stabilizer (HALS 123), 20 kg nano-silica, 25 kg nano-boron nitride, 15 kg paraffin oil, 1 kg antioxidant DMQ, 5 kg zinc oxide (purity above 95.5 wt%), 1 kg stearic acid, 2 kg silane coupling agent, 4 kg vulcanizing agent DCP, and 2 kg vulcanization accelerator (TAIC, triallyl isocyanurate).

[0124] The preparation steps are the same as in Example 1, except that the 1.5 kg of TAIC accelerator and 0.5 kg of insoluble sulfur in step (7) are replaced with 2 kg of TAIC accelerator.

[0125] Comparative Example 9 Commercially available insulating EPDM.

[0126] Test case The test pieces were 115mm×115mm×2mm and 100mm×100mm×1mm in size. The vulcanization process parameters for the test pieces were: temperature 180±2℃, time 12min, and pressure 10MPa.

[0127] Tensile strength and elongation at break were determined according to GB / T 528-2009 standard. Type I dumbbell specimens were used as samples, and the tensile speed was 500 mm / min.

[0128] Volume resistivity was measured according to GB / T 1692-2008 standard, with an electrode diameter of 50 mm and a test piece size of 100 mm × 100 mm × 1 mm.

[0129] The breakdown strength was determined according to GB / T 1695-2005 standard, with an electrode diameter of 25 mm and a test piece size of 100 mm × 100 mm × 1 mm.

[0130] The dielectric constant and dielectric loss tangent were determined according to Method A of GB / T 1693-2007, with a measuring electrode diameter of 50 mm and a test piece size of 100 mm × 100 mm × 1 mm.

[0131] The UV aging performance was tested according to ASTM G154-2025 standard, using a UVA-340 lamp with an irradiance of 0.89 W / (m²). 2(@340nm) The test cycle conditions were: alternating between 8h of light exposure (temperature 60±3℃) and 4h of condensation (temperature 50±3℃), with a total aging time of 3000h.

[0132] The test results are shown in Table 1.

[0133] Table 1

[0134] As can be seen, the overall performance of the embodiments of the present invention is superior compared with commercially available products (Comparative Example 9). Comparative Example 9 exhibited cracking after thermal and photo-aging, resulting in a significant decrease in its overall performance.

[0135] Compared with Example 1, Examples 2 and 3 show that by using the EPDM rubber employed in Example 1 and controlling the rubber viscosity, ethylene content, and ENB content within suitable ranges, superior overall mechanical properties can be obtained. Furthermore, the higher viscosity of the EPDM rubber in Example 1 facilitates uniform dispersion of the filler, enhances its reinforcing effect, and promotes the construction of the insulation network, thereby improving the insulation performance of the material.

[0136] Example 4, compared to Example 1, shows that adjusting the ratio of nano-boron nitride to nano-silica can further improve the material's resistance to ultraviolet radiation and thermo-oxidative aging. SiO2 has a high specific surface area, allowing it to form more hydrogen bonds with EPDM rubber molecular chains, creating a denser polymer-filler network; however, excessive content may affect dispersibility. Nano-boron nitride possesses excellent thermal conductivity, insulation, and lubricity, reducing the resistance to rubber molecular chain movement. Its overlapping within the composite material forms a continuous and effective thermally conductive network and physical barrier, effectively blocking oxygen and ultraviolet radiation.

[0137] Compared with Example 1, Comparative Examples 1-3 show that adding only antioxidant AO168 (Comparative Example 1), adding only RIANOX®1010 (Comparative Example 2), or not adding light stabilizers HALS 622 and HALS 123 (Comparative Example 3) all reduce the heat aging resistance and UV aging resistance of the materials.

[0138] Comparative Example 4, compared to Example 1, shows that when the UV absorber was replaced by UV-531 instead of UV-329, the resulting material exhibited incomplete vulcanization. This is because UV-531 (2-hydroxy-4-n-octyloxybenzophenone) has a benzophenone structure, which can capture free radicals, while the DCP vulcanization system relies on free radical reactions, thereby inhibiting the crosslinking reaction.

[0139] Comparative Example 5, compared to Example 1, shows that after modifying nano-cerium oxide with a silane coupling agent, the mechanical and electrical properties of the material are significantly better than those of the system without this component, as demonstrated in the UV aging test. This is mainly attributed to the absorption of ultraviolet light by nano-cerium oxide, thereby improving the material's UV resistance.

[0140] Comparative Example 6, compared to Example 1, shows that after replacing dicumyl peroxide and triallyl isocyanurate with zinc dialkyl dithiophosphate, a yellowing resistance accelerator, the material exhibited significant yellowing after UV aging tests, along with a marked decrease in mechanical and electrical properties. This may be because zinc dialkyl dithiophosphate is unstable under UV light, and the active substances generated by its photolysis can destroy the cross-linked network and generate polar degradation products.

[0141] Comparative Example 7, compared to Example 1, shows that the system without added titanium dioxide exhibits significantly inferior mechanical and electrical properties after UV aging compared to Example 1. This is because titanium dioxide can absorb some ultraviolet light, thereby improving the material's resistance to UV aging.

[0142] Comparative Example 8, compared with Example 1, shows that if no sulfur is added and only TAIC accelerator is used, the crosslinking mainly relies on the formation of carbon-carbon bonds by peroxide free radicals, resulting in a low crosslinking density and an uneven network. At the same time, the flexibility and stabilizing effect of sulfur bridges on free radicals are lacking, so the mechanical properties, heat aging resistance and UV aging resistance are significantly reduced.

[0143] Given that the UV-resistant EPDM rubber composite material provided in this embodiment possesses both excellent mechanical and electrical insulation properties, as well as good resistance to UV aging and heat aging, it meets the requirements for cable accessories and is suitable for joints, terminations, and other applications. This material can be used as insulation for cable accessories such as 0-500kV cable joints and terminations. Under long-term UV irradiation and thermal conditions, this material maintains stable electrical and mechanical properties, thereby helping to improve the stability of cable operation and extend the service life of cable accessories.

[0144] The present invention has been described in detail above with reference to the embodiments. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. An insulating and UV-resistant EPDM rubber composite material, characterized in that, The following raw materials are included in the preparation by weight: 100 parts of EPDM rubber 10-30 parts titanium dioxide 30-80 parts of nano-insulating filler 2-5 parts of vulcanizing agent 1-4 parts of vulcanization accelerator Antioxidant 0.5-2 parts, 2-5 parts of nano-cerium oxide, 0.5-2.5 parts of ultraviolet absorber, Light stabilizer 0.5-2 parts; The antioxidants include hindered phenolic antioxidants and phosphite antioxidants; The ultraviolet absorber is a benzotriazole ultraviolet absorber; The vulcanization accelerator includes triallyl isocyanurate and sulfur.

2. The insulating and UV-resistant EPDM rubber composite material according to claim 1, characterized in that, The EPDM rubber has a Mooney viscosity ML(1+4, 125℃) ≥ 60, an ethylene content ≥ 70%, and an ENB content ≤ 4.5%.

3. The insulating and UV-resistant EPDM rubber composite material according to claim 1, characterized in that, The titanium dioxide crystal form is rutile; and / or, the titanium dioxide content is 10-25 parts; and / or, the average particle size of the titanium dioxide is 0.1-0.3 μm; And / or, the nano-insulating filler comprises nano-silica and nano-boron nitride, wherein the mass ratio of nano-silica to nano-boron nitride is 1:0.5-2; and / or, the average particle size of the nano-insulating filler is 10-100 nm; and / or, the nano-insulating filler is 30-60 parts. And / or, the nano-cerium oxide is modified with a silane coupling agent; and / or, the nano-cerium oxide has an average particle size of 15-30 nm and a specific surface area of ​​30-60 m². 2 / g.

4. The insulating and UV-resistant EPDM rubber composite material according to claim 1, characterized in that, The vulcanizing agent is a peroxide vulcanizing agent; and / or, the vulcanizing agent is 2-4 parts; And / or, the sulfur is insoluble sulfur; and / or, the mass ratio of the triallyl isocyanurate to sulfur is 1:0.2-0.5; and / or, the vulcanization accelerator is 1-3 parts.

5. The insulating and UV-resistant EPDM rubber composite material according to claim 1, characterized in that, The hindered phenolic antioxidant is selected from at least one of antioxidant 1010, antioxidant 1076, and antioxidant 1024; and / or, the phosphite antioxidant is antioxidant 168; and / or, the mass ratio of the hindered phenolic antioxidant to the phosphite antioxidant is 1:0.4-0.8; and / or, the total amount of the antioxidant is 0.5-1.5 parts. And / or, the ultraviolet absorber is selected from at least one of UV326, UV328, UV329, and UV1164.

6. The insulating and UV-resistant EPDM rubber composite material according to claim 1, characterized in that, The light stabilizer is selected from at least one of HALS944, HALS770, HALS622, HALS119, HALS123, HALS791, and HALS5230; optionally, the light stabilizer includes HALS622 and HALS123, wherein the mass ratio of HALS622 to HALS123 is 1:0.4-0.

6.

7. The insulating and UV-resistant EPDM rubber composite material according to claim 1, characterized in that, The raw materials for preparation also include other additives, which are selected from at least one of plasticizers, antioxidants, activators, and coupling agents; optionally, the other additives are 16-45 parts.

8. The insulating and UV-resistant EPDM rubber composite material according to claim 7, characterized in that, The plasticizer is selected from at least one of paraffin oil, naphthenic oil, and white oil; and / or, the plasticizer is 12-30 parts; and / or, the antioxidant is selected from at least one of antioxidant RD, antioxidant MB, antioxidant TMQ, antioxidant DMQ, and antioxidant MBZ; and / or, the antioxidant is 1-2 parts; and / or, the activator is selected from at least one of zinc oxide, stearic acid, and zinc stearate; and / or, the activator is 2-6 parts; and / or, the coupling agent is selected from at least one of bis-(γ-triethoxysilylpropyl)tetrasulfide and vinyltris(β-methoxyethoxy)silane; and / or, the coupling agent is 1-3 parts.

9. A method for preparing the insulating and UV-resistant EPDM rubber composite material according to any one of claims 1-8, characterized in that, Includes the following steps: The EPDM rubber, titanium dioxide, nano-insulating filler, nano-cerium oxide, antioxidant, ultraviolet absorber, light stabilizer, and optionally plasticizer, antioxidant, activator and coupling agent are mixed under heating conditions for the first stage, then cooled, and the vulcanizing agent and vulcanization accelerator are added for the second stage of mixing to obtain the final product.

10. The use of the insulating and UV-resistant EPDM rubber composite material according to any one of claims 1-8 in the preparation of cable accessories.

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