Anti-aging aerial cable

Abstract

The invention relates to the technical field of cable materials, and provides an anti-aging aerial cable. The anti-aging aerial cable comprises conductor wire cores and an outer sheath layer, the outer sheath layer is prepared from the following raw materials in parts by weight: 60 to 70 parts of ethylene propylene diene monomer, 15 to 18 parts of fluorine-doped titanium dioxide supported anti-aging agent, 7 to 10 parts of aluminum hydroxide, 4 to 6 parts of montmorillonite, 2.5 to 3.5 parts of silane coupling agent, 0.8 to 1.2 parts of hindered amine light stabilizer, 0.5 to 0.8 part of phosphite ester antioxidant, 0.6 to 1.0 part of ultraviolet absorbent, 1.5 to 2 parts of cross-linking agent and 0.5 to 1 part of assistant cross-linking agent. According to the anti-aging aerial cable prepared in the invention, the anti-aging aerial cable is improved, and the capability of a traditional aerial cable in coping with multi-factor coupling aging is improved, so that the problem of aging failure caused by a multi-factor coupling effect is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of cable materials, and in particular to an aging-resistant overhead cable. Background Art

[0002] As critical infrastructure for power transmission and communications networks, overhead cables play an irreplaceable role in urban and rural power grid construction, railway electrification, and the integration of new energy sources. In this area, overhead cables, with their relatively low cost and convenient construction, have become a crucial component of urban and rural power distribution networks. Whether it's grid renovations in older urban communities or upgrading rural areas from no electricity to electricity and from low voltage to high voltage, overhead cables shoulder the crucial task of efficiently and stably transmitting electricity from substations to every household, supporting the electricity needs of residents, businesses, and various public facilities.

[0003] However, with the rapid development of power grids towards high voltage and intelligentization, as well as the frequent occurrence of extreme climate events, the aging resistance of overhead cables has become a core issue that restricts their service life and system reliability. Traditional overhead cables are susceptible to the coupling effects of multiple factors such as ultraviolet rays, ozone, thermal oxygen, and acid rain in long-term outdoor environments, leading to aging failures such as cracking of the insulation layer, oxidation of the conductor, and loss of mechanical strength, causing power outages and economic losses. Existing technologies are mostly designed for a single aging factor and are difficult to resist the synergistic effects of ultraviolet rays, thermal oxygen, and acid rain. Currently, common aging-resistant overhead cable technologies on the market mainly focus on protecting against a single aging factor. For example, in order to resist ultraviolet aging, some cables use the method of adding ultraviolet absorbers or light stabilizers. These additives can absorb or shield ultraviolet rays and reduce the damage of ultraviolet rays to cable materials. However, this method can only delay the process of ultraviolet aging to a certain extent, and has limited effect on other aging factors such as thermal oxygen and acid rain.

[0004] In order to solve the above technical problems, the present invention proposes a new aging-resistant overhead cable. Summary of the Invention

[0005] The present invention proposes an aging-resistant overhead cable, which improves the ability of traditional overhead cables in coping with multi-factor coupling aging, so as to solve the problem of aging failure caused by multi-factor coupling; it improves the situation that the existing aging-resistant overhead cable technology only protects against a single aging factor, and is difficult to fully resist the aging factors in complex outdoor environments, thereby affecting the cable service life and system reliability.

[0006] The technical solutions of the present invention are as follows: In the first aspect, the present invention proposes an aging-resistant overhead cable, comprising a conductor core and an outer sheath layer, wherein the outer sheath layer is composed of the following raw materials in parts by weight: 60-70 parts of ethylene propylene diene monomer rubber, 15-18 parts of fluorine-doped titanium dioxide-loaded antioxidant, 7-10 parts of aluminum hydroxide, 4-6 parts of montmorillonite, 2.5-3.5 parts of silane coupling agent, 0.8-1.2 parts of hindered amine light stabilizer, 0.5-0.8 parts of phosphite antioxidant, 0.6-1.0 parts of ultraviolet absorber, 1.5-2 parts of crosslinking agent, and 0.5-1 parts of auxiliary crosslinking agent.

[0007] As a further technical solution, the preparation method of the fluorine-doped titanium dioxide-supported antioxidant includes: dissolving N-isopropyl-N'-phenyl-p-phenylenediamine and 2,6-di-tert-butyl-4-methylphenol in toluene, adding silane coupling agent KH-550, heating to 75-85°C under nitrogen protection, stirring and reacting for 5-6 hours, adjusting the pH to 6-7 with acetic acid, and removing the solvent by reduced pressure distillation to obtain an IPPD-BHT complex containing a silane bond; mixing the prepared IPPD-BHT complex and fluorine-doped titanium dioxide, adding ethanol for ultrasonic dispersion, stirring at a temperature of 55-65°C for 3.5-4.5 hours, centrifuging, washing, and drying to obtain the fluorine-doped titanium dioxide-supported antioxidant.

[0008] As a further technical solution, the weight ratio of N-isopropyl-N'-phenyl-p-phenylenediamine, 2,6-di-tert-butyl-4-methylphenol, toluene and silane coupling agent is 1.2-1.5:0.3-0.5:6-8:0.2-0.3.

[0009] As a further technical solution, the weight ratio of the IPPD-BHT composite, fluorine-doped titanium dioxide and ethanol is 1.5-2:0.5-0.8:8-12.

[0010] As a further technical solution, the preparation method of fluorine-doped titanium dioxide includes: dissolving tetrabutyl titanate in acetic acid, adding polyethyleneimine, grinding for 20-30 minutes to form a gel-like mixture, controlling the heating rate to 5-10°C / min, heating to 400-500°C and calcining for 4-8 hours to form a mesoporous titanium dioxide matrix, mixing with ammonium fluoride, and calcining again at 400-600°C for 6-10 hours. After washing with ethanol and deionized water, the mixture is dried.

[0011] As a further technical solution, the weight ratio of tetrabutyl titanate, acetic acid and polyethyleneimine is 10-15:2-4:0.5-1, wherein the volume concentration of acetic acid is 30-50%.

[0012] As a further technical solution, the weight ratio of the titanium dioxide matrix to ammonium fluoride is 1:0.05-0.1.

[0013] As a further technical solution, the ultraviolet absorber includes Tinuvin 326 and nano-cerium dioxide (particle size 20 nm) in a weight ratio of 1-2:1.

[0014] In a second aspect, the present invention provides a method for preparing an aging-resistant overhead cable, comprising the steps of: S1. Internal mixing and blending: adding EPDM rubber to an internal mixer and mixing for 5-6 minutes; adding fluorine-doped titanium dioxide-supported antioxidant, aluminum hydroxide, montmorillonite, hindered amine light stabilizer, phosphite antioxidant, ultraviolet absorber, crosslinking agent, and auxiliary crosslinking agent and continuing mixing for 5-6 minutes to obtain a rubber compound; S2. Extrusion vulcanization: transfer the rubber material to a vulcanizer and vulcanize it at 160-170°C for 20-30 minutes, then leave it for 20-24 hours to obtain an outer sheath layer, which is then extruded and coated on the surface of the conductor core through a twin-screw extruder to obtain an aging-resistant overhead cable.

[0015] As a further technical solution, the mixing temperature is 122-126°C; and the temperature of the twin-screw extruder is 170-180°C.

[0016] The working principle and beneficial effects of the present invention are: The fluorine-doped titanium dioxide used in the preparation of the fluorine-doped titanium dioxide-supported antioxidant in this invention possesses unique electronic structure and optical properties. Under ultraviolet light irradiation, the fluorine-doped titanium dioxide absorbs a significant amount of ultraviolet light, with an absorption rate exceeding 95%. This is because the introduction of fluorine modifies the band structure of titanium dioxide, broadening its light absorption range and enhancing its response to ultraviolet light. Furthermore, the fluorine defect sites on the surface of the fluorine-doped titanium dioxide are capable of capturing hydroxyl radicals (·OH). When materials are exposed to aging factors such as heat, oxygen, and humidity, free radicals are generated. These radicals can trigger polymer chain breakage, leading to material performance degradation. The fluorine defect sites on the surface of the fluorine-doped titanium dioxide can rapidly capture ·OH radicals, thereby inhibiting the free radical chain reaction, delaying polymer chain breakage, and improving the material's tensile strength retention. This, in turn, enhances the material's synergistic protection against aging factors such as ultraviolet light, oxygen, and humidity.

[0017] The IPPD-BHT complex and fluorine-doped titanium dioxide loading in this invention exhibit a synergistic effect. N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD) and 2,6-di-tert-butyl-4-methylphenol (BHT) are coupled with a silane coupling agent to form an IPPD-BHT complex containing silane bonds, which is then loaded onto the fluorine-doped titanium dioxide. IPPD exhibits excellent dynamic resistance to ozone aging. It preferentially reacts with ozone in an ozone environment, inhibiting ozone attack on the polymer chains and preventing crack propagation. BHT primarily provides static antioxidant protection, reacting with free radicals to terminate free radical chain reactions and protect the polymer chains from oxidation. The two are combined and loaded onto the fluorine-doped titanium dioxide, providing an excellent dispersion carrier for the IPPD-BHT complex, allowing it to be evenly distributed throughout the material and fully exerting its synergistic anti-aging effect. At the same time, the UV shielding and free radical quenching effects of fluorine-doped titanium dioxide cooperate with the anti-ozone and antioxidant effects of the IPPD-BHT complex to jointly improve the material's ability to retain elongation at break.

[0018] The UV absorber Tinuvin 326 and nano-cerium dioxide in this invention exhibit complementary absorption characteristics. Tinuvin 326 is an organic UV absorber that absorbs UV light within a specific wavelength range, but its absorption band is relatively narrow. Nano-cerium dioxide (particle size 20 nm) is an inorganic UV absorber with a different absorption band. When combined in a specific weight ratio (1-2:1), Tinuvin 326 and nano-cerium dioxide can cover the entire UV absorption range of 290-400 nm. This is due to their different molecular structures and electronic transition energy levels, resulting in different absorption characteristics for UV light of different wavelengths. The synergistic effect of the organic and inorganic UV absorbers can reduce the generation of photooxidation initiation sites and minimize UV damage to polymer molecular chains, thereby improving the material's aging resistance.

[0019] The outer sheath layer formula of the present invention includes multiple antioxidants such as fluorine-doped titanium dioxide-loaded antioxidant, hindered amine light stabilizer, phosphite antioxidant and ultraviolet absorber. These antioxidants have different anti-aging mechanisms, and they work together to improve the aging resistance of the material. Fluorine-doped titanium dioxide-loaded antioxidant mainly delays the aging of the material through ultraviolet shielding and free radical quenching; hindered amine light stabilizer can capture free radicals, decompose peroxides, and inhibit the progress of photooxidation reaction; phosphite antioxidant can react with hydroperoxide and decompose it into stable products, thereby protecting the polymer molecular chain; ultraviolet absorber can absorb ultraviolet rays and reduce the damage of ultraviolet rays to the material. The synergistic effect of multiple antioxidants can protect the material from different angles and mechanisms, comprehensively resisting various aging factors in complex outdoor environments, such as ultraviolet rays, thermal oxygen, humidity, ozone, etc., and significantly improving the material's tensile strength retention rate and elongation at break retention ability. DETAILED DESCRIPTION

[0020] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0021] It should be noted that the silane coupling agent in the present invention is KH-560; the hindered amine light stabilizer is light stabilizer 770 (LS-770); the phosphite antioxidant is Irganox 168; the crosslinking agent is dicumyl peroxide (DCP); and the co-crosslinking agent is triallyl isocyanurate (TAIC).

[0022] Example 1 This embodiment provides an aging-resistant overhead cable, including a conductor core and an outer sheath layer, wherein the outer sheath layer is composed of the following raw materials in parts by weight: 65 parts of ethylene propylene diene monomer rubber, 16 parts of fluorine-doped titanium dioxide-loaded antioxidant, 8 parts of aluminum hydroxide, 5 parts of montmorillonite, 6 parts of silane coupling agent, 1 part of hindered amine light stabilizer, 0.6 parts of phosphite antioxidant, 0.8 parts of ultraviolet absorber, 1.8 parts of crosslinking agent, and 0.7 parts of auxiliary crosslinking agent.

[0023] The preparation method of the fluorine-doped titanium dioxide-supported antioxidant includes: dissolving N-isopropyl-N'-phenyl-p-phenylenediamine and 2,6-di-tert-butyl-4-methylphenol in toluene, adding a silane coupling agent KH-550, heating to 80°C under nitrogen protection, stirring and reacting for 5.5 hours, adjusting the pH to 6.5 with acetic acid, and removing the solvent by reduced pressure distillation to obtain an IPPD-BHT complex containing a silane bond; the weight ratio of N-isopropyl-N'-phenyl-p-phenylenediamine, 2,6-di-tert-butyl-4-methylphenol, toluene and the silane coupling agent is 1.3:0.4:7:0.25; Tetrabutyl titanate was dissolved in acetic acid with a volume concentration of 4%, polyethyleneimine was added, and the mixture was ground for 25 minutes to form a gel-like mixture. The mixture was then heated to 450°C at a heating rate of 8°C / min and calcined for 6 hours to form a mesoporous titanium dioxide matrix, which was then mixed with ammonium fluoride and calcined again at 500°C for 8 hours. After washing with ethanol and deionized water, the mixture was dried to obtain fluorine-doped titanium dioxide. The weight ratio of tetrabutyl titanate, acetic acid, and polyethyleneimine was 12:3:0.8, and the weight ratio of the titanium dioxide matrix to ammonium fluoride was 1:0.07. The prepared IPPD-BHT composite and fluorine-doped titanium dioxide were mixed, ethanol was added for ultrasonic dispersion, and the mixture was stirred at 60°C for 4 hours. The mixture was centrifuged, washed, and dried to obtain a fluorine-doped titanium dioxide-supported antioxidant. The weight ratio of the IPPD-BHT composite, fluorine-doped titanium dioxide, and ethanol was 1.8:0.7:10. The ultraviolet absorber comprises Tinuvin 326 and nano-cerium dioxide in a weight ratio of 1.5:1; The preparation method of the aging-resistant overhead cable comprises the following steps: S1. Internal mixing and blending: add EPDM rubber to an internal mixer and mix for 5.5 min; add fluorine-doped titanium dioxide-supported antioxidant, aluminum hydroxide, montmorillonite, hindered amine light stabilizer, phosphite antioxidant, ultraviolet absorber, crosslinking agent, and auxiliary crosslinking agent and continue mixing for 5.5 min to obtain a rubber compound; the mixing temperature is 124°C; S2. Extrusion vulcanization: The rubber material is transferred to a vulcanizer and vulcanized at 165° C. for 25 minutes, and then allowed to stand for 22 hours to obtain an outer sheath layer. The outer sheath layer is extruded through a twin-screw extruder at 175° C. and coated on the surface of the conductor core to obtain an aging-resistant overhead cable.

[0024] Example 2 This embodiment provides an aging-resistant overhead cable, including a conductor core and an outer sheath layer, wherein the outer sheath layer is composed of the following raw materials in parts by weight: 60 parts of ethylene propylene diene monomer rubber, 15 parts of fluorine-doped titanium dioxide-loaded antioxidant, 7 parts of aluminum hydroxide, 4 parts of montmorillonite, 2.5 parts of silane coupling agent, 0.8 parts of hindered amine light stabilizer, 0.5 parts of phosphite antioxidant, 0.6 parts of ultraviolet absorber, 1.5 parts of crosslinking agent, and 0.5 parts of co-crosslinking agent.

[0025] The preparation method of the fluorine-doped titanium dioxide-supported antioxidant includes: dissolving N-isopropyl-N'-phenyl-p-phenylenediamine and 2,6-di-tert-butyl-4-methylphenol in toluene, adding a silane coupling agent KH-550, heating to 75°C under nitrogen protection, stirring and reacting for 5 hours, adjusting the pH to 6 with acetic acid, and removing the solvent by reduced pressure distillation to obtain an IPPD-BHT complex containing a silane bond; the weight ratio of N-isopropyl-N'-phenyl-p-phenylenediamine, 2,6-di-tert-butyl-4-methylphenol, toluene and the silane coupling agent is 1.2:0.3:6:0.2; Tetrabutyl titanate was dissolved in acetic acid with a volume concentration of 30%, polyethyleneimine was added, and the mixture was ground for 20 minutes to form a gel-like mixture. The mixture was then heated to 400°C at a heating rate of 5°C / min and calcined for 4 hours to form a mesoporous titanium dioxide matrix, which was then mixed with ammonium fluoride and calcined again at 400°C for 6 hours. After washing with ethanol and deionized water, the mixture was dried to obtain fluorine-doped titanium dioxide. The weight ratio of tetrabutyl titanate, acetic acid, and polyethyleneimine was 10:2:0.5, and the weight ratio of the titanium dioxide matrix to ammonium fluoride was 1:0.05. The prepared IPPD-BHT composite and fluorine-doped titanium dioxide were mixed, ethanol was added for ultrasonic dispersion, and the mixture was stirred at 55°C for 3.5 hours. The mixture was centrifuged, washed, and dried to obtain a fluorine-doped titanium dioxide-supported antioxidant. The weight ratio of the IPPD-BHT composite, fluorine-doped titanium dioxide, and ethanol was 1.5:0.5:8. The ultraviolet absorber comprises Tinuvin 326 and nano-cerium dioxide in a weight ratio of 1:1; The preparation method of the aging-resistant overhead cable comprises the following steps: S1. Internal mixing and blending: add EPDM rubber to an internal mixer and mix for 5 minutes; add fluorine-doped titanium dioxide-supported antioxidant, aluminum hydroxide, montmorillonite, hindered amine light stabilizer, phosphite antioxidant, ultraviolet absorber, crosslinking agent, and auxiliary crosslinking agent and continue mixing for 5 minutes to obtain a rubber compound; the mixing temperature is 122°C; S2. Extrusion vulcanization: The rubber material is transferred to a vulcanizer and vulcanized at 160° C. for 20 minutes, and then allowed to stand for 20 hours to obtain an outer sheath layer. The outer sheath layer is extruded through a twin-screw extruder at 170° C. and coated on the surface of the conductor core to obtain an aging-resistant overhead cable.

[0026] Example 3 This embodiment provides an aging-resistant overhead cable, including a conductor core and an outer sheath layer, wherein the outer sheath layer is composed of the following raw materials in parts by weight: 70 parts of ethylene propylene diene monomer rubber, 18 parts of fluorine-doped titanium dioxide-loaded antioxidant, 10 parts of aluminum hydroxide, 6 parts of montmorillonite, 3.5 parts of silane coupling agent, 1.2 parts of hindered amine light stabilizer, 0.8 parts of phosphite antioxidant, 1.0 part of ultraviolet absorber, 2 parts of crosslinking agent, and 1 part of auxiliary crosslinking agent.

[0027] The preparation method of the fluorine-doped titanium dioxide-supported antioxidant includes: dissolving N-isopropyl-N'-phenyl-p-phenylenediamine and 2,6-di-tert-butyl-4-methylphenol in toluene, adding a silane coupling agent KH-550, heating to 85°C under nitrogen protection, stirring and reacting for 6 hours, adjusting the pH to 7 with acetic acid, and removing the solvent by reduced pressure distillation to obtain an IPPD-BHT complex containing a silane bond; the weight ratio of N-isopropyl-N'-phenyl-p-phenylenediamine, 2,6-di-tert-butyl-4-methylphenol, toluene and the silane coupling agent is 1.5:0.5:8:0.3; Tetrabutyl titanate was dissolved in acetic acid with a volume concentration of 50%, polyethyleneimine was added, and the mixture was ground for 30 minutes to form a gel-like mixture. The mixture was then heated to 500°C at a heating rate of 10°C / min and calcined for 8 hours to form a mesoporous titanium dioxide matrix, which was then mixed with ammonium fluoride and calcined again at 600°C for 10 hours. After washing with ethanol and deionized water, the mixture was dried to obtain fluorine-doped titanium dioxide. The weight ratio of tetrabutyl titanate, acetic acid, and polyethyleneimine was 15:4:1, and the weight ratio of the titanium dioxide matrix to ammonium fluoride was 1:0.1. The prepared IPPD-BHT composite and fluorine-doped titanium dioxide were mixed, ethanol was added for ultrasonic dispersion, and the mixture was stirred at 65°C for 4.5 hours. The mixture was centrifuged, washed, and dried to obtain a fluorine-doped titanium dioxide-supported antioxidant. The weight ratio of the IPPD-BHT composite, fluorine-doped titanium dioxide, and ethanol was 2:0.8:12. The ultraviolet absorber comprises Tinuvin 326 and nano-cerium dioxide in a weight ratio of 2:1; The preparation method of the aging-resistant overhead cable comprises the following steps: S1. Internal mixing and blending: add EPDM rubber to an internal mixer and mix for 6 minutes; add fluorine-doped titanium dioxide-supported antioxidant, aluminum hydroxide, montmorillonite, hindered amine light stabilizer, phosphite antioxidant, ultraviolet absorber, crosslinking agent, and auxiliary crosslinking agent and continue mixing for 6 minutes to obtain a rubber compound; the mixing temperature is 126°C; S2. Extrusion vulcanization: The rubber material is transferred to a vulcanizer and vulcanized at 170°C for 30 minutes, and then left for 24 hours to obtain an outer sheath layer. The outer sheath layer is extruded through a twin-screw extruder at 180°C and coated on the surface of the conductor core to obtain an aging-resistant overhead cable.

[0028] Comparative Example 1 Comparative Example 1 In the preparation of the fluorine-doped titanium dioxide-supported antioxidant, the ammonium fluoride calcination step was omitted, and the undoped mesoporous titanium dioxide matrix was directly used to support the IPPD-BHT composite. The rest was the same as in Example 1, and the preparation steps were the same as in Example 1.

[0029] Comparative Example 2 In the preparation of the fluorine-doped titanium dioxide-supported antioxidant in Comparative Example 2, the IPPD-BHT complex was first loaded onto undoped mesoporous titanium dioxide by an impregnation method, and then calcined with ammonium fluoride. The rest was the same as in Example 1, and the preparation steps were the same as in Example 1.

[0030] The preparation method of the antioxidant is as follows: the preparation method of the fluorine-doped titanium dioxide-supported antioxidant comprises: dissolving N-isopropyl-N'-phenyl-p-phenylenediamine and 2,6-di-tert-butyl-4-methylphenol in toluene, adding a silane coupling agent KH-550, heating to 80° C. under nitrogen protection, stirring and reacting for 5.5 hours, adjusting the pH to 6.5 with acetic acid, and removing the solvent by reduced pressure distillation to obtain an IPPD-BHT complex containing a silane bond; the weight ratio of N-isopropyl-N'-phenyl-p-phenylenediamine, 2,6-di-tert-butyl-4-methylphenol, toluene and the silane coupling agent is 1.3:0.4:7:0.25; Tetrabutyl titanate was dissolved in acetic acid with a volume concentration of 4%, polyethyleneimine was added, and the mixture was ground for 25 minutes to form a gel-like mixture. The mixture was then heated to 450°C at a heating rate of 8°C / min and calcined for 6 hours to form a mesoporous titanium dioxide matrix. The weight ratio of tetrabutyl titanate, acetic acid, and polyethyleneimine was 12:3:0.8. The prepared IPPD-BHT complex and titanium dioxide matrix were mixed, ethanol was added for ultrasonic dispersion, stirred at 60°C for 4 hours, centrifuged, washed and dried; then mixed with 0.07wt% ammonium fluoride relative to the above product, calcined again at 500°C for 8 hours, washed with ethanol and deionized water, and dried to obtain a fluorine-doped titanium dioxide-loaded antioxidant; the weight ratio of the IPPD-BHT complex, titanium dioxide matrix and ethanol was 1.8:0.7:10.

[0031] Comparative Example 3 In Comparative Example 3, the fluorine-doped titanium dioxide-supported antioxidant was replaced with an antioxidant 4010NA of equal mass, and the rest was the same as in Example 1, and the preparation steps were the same as in Example 1.

[0032] Comparative Example 4 In Comparative Example 4, the fluorine-doped titanium dioxide-supported antioxidant was replaced by an antioxidant of equal mass, DTPD. The rest was the same as in Example 1, and the preparation steps were the same as in Example 1.

[0033] Comparative Example 5 In Comparative Example 5, Tinuvin 326 was replaced by an equal mass of nano-cerium dioxide, and the rest was the same as in Example 1, and the preparation steps were the same as in Example 1.

[0034] Comparative Example 6 In Comparative Example 6, nano-cerium dioxide was replaced by an equal mass of Tinuvin 326, and the rest was the same as in Example 1, and the preparation steps were the same as in Example 1.

[0035] Test Example: The outer sheaths of the aging-resistant overhead cables prepared in Examples 1-3 and Comparative Examples 1-6 were subjected to the following tests: Tensile strength and elongation at break: tested in accordance with GB / T2951.11-2008; UV aging: Place the sample in a xenon lamp aging chamber (wavelength 340nm, irradiation intensity 0.35W / m², black mark temperature 60℃, relative humidity 50%) and irradiate it in a cycle; Thermal oxidative aging: Place the sample in a hot air aging box at 100°C; Hygrothermal aging: place the sample in an environment of 85℃ / 85%RH; Ozone aging: The samples were placed in an ozone environment at 40°C and a concentration of 50 pphm.

[0036] The samples were subjected to UV aging for 500 hours, thermal oxygen aging for 100 hours, damp heat aging for 360 hours, and ozone aging for 60 hours. After the tests, the tensile strength and elongation at break were tested again, and the tensile strength retention rate was calculated according to the following formula: Tensile strength retention rate (%) = tensile strength after aging / tensile strength before heat aging × 100%; The test results are shown in Table 1 below: Table 1

[0037] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An aging-resistant overhead cable, characterized in that: The invention comprises a conductor core and an outer sheath layer, wherein the outer sheath layer is composed of the following raw materials in parts by weight: 60-70 parts of EPDM rubber, 15-18 parts of fluorine-doped titanium dioxide-loaded antioxidant, 7-10 parts of aluminum hydroxide, 4-6 parts of montmorillonite, 2.5-3.5 parts of silane coupling agent, 0.8-1.2 parts of hindered amine light stabilizer, 0.5-0.8 parts of phosphite antioxidant, 0.6-1.0 parts of ultraviolet absorber, 1.5-2 parts of crosslinking agent, and 0.5-1 parts of auxiliary crosslinking agent.

2. The aging-resistant overhead cable according to claim 1, characterized in that: The preparation method of the fluorine-doped titanium dioxide supported antioxidant comprises: dissolving N-isopropyl-N'-phenyl-p-phenylenediamine and 2,6-di-tert-butyl-4-methylphenol in toluene, adding a silane coupling agent KH-550, heating to 75-85°C under nitrogen protection, stirring and reacting for 5-6 hours, adjusting the pH to 6-7 with acetic acid, and removing the solvent by reduced pressure distillation to obtain an IPPD-BHT complex containing a silane bond; mixing the prepared IPPD-BHT complex and fluorine-doped titanium dioxide, adding ethanol for ultrasonic dispersion, stirring at a temperature of 55-65°C for 3.5-4.5 hours, centrifuging, washing, and drying to obtain the fluorine-doped titanium dioxide supported antioxidant.

3. The aging-resistant overhead cable according to claim 2, characterized in that: The weight ratio of the N-isopropyl-N'-phenyl-p-phenylenediamine, 2,6-di-tert-butyl-4-methylphenol, toluene and silane coupling agent is 1.2-1.5:0.3-0.5:6-8:0.2-0.

3.

4. The aging-resistant overhead cable according to claim 2, characterized in that: The weight ratio of the IPPD-BHT composite, fluorine-doped titanium dioxide and ethanol is 1.5-2:0.5-0.8:8-12.

5. The aging-resistant overhead cable according to claim 2, characterized in that: The preparation method of fluorine-doped titanium dioxide includes: dissolving tetrabutyl titanate in acetic acid, adding polyethyleneimine, grinding for 20-30 minutes to form a gel-like mixture, controlling the heating rate to 5-10°C / min, heating to 400-500°C, calcining for 4-8 hours to form a mesoporous titanium dioxide matrix, mixing with ammonium fluoride, calcining again at 400-600°C for 6-10 hours, washing with ethanol and deionized water, and drying to obtain the obtained product.

6. The aging-resistant overhead cable according to claim 5, characterized in that: The weight ratio of tetrabutyl titanate, acetic acid and polyethyleneimine is 10-15:2-4:0.5-1, wherein the volume concentration of acetic acid is 30-50%.

7. The aging-resistant overhead cable according to claim 5, characterized in that: The weight ratio of the titanium dioxide matrix to ammonium fluoride is 1:0.05-0.

1.

8. The aging-resistant overhead cable according to claim 1, characterized in that: The ultraviolet absorber comprises Tinuvin 326 and nano-cerium dioxide in a weight ratio of 1-2:

1.

9. The method for preparing an aging-resistant overhead cable according to any one of claims 1 to 8, characterized in that the steps include: S1. Internal mixing and blending: adding EPDM rubber to an internal mixer and mixing for 5-6 minutes; adding fluorine-doped titanium dioxide-supported antioxidant, aluminum hydroxide, montmorillonite, hindered amine light stabilizer, phosphite antioxidant, ultraviolet absorber, crosslinking agent, and auxiliary crosslinking agent and continuing mixing for 5-6 minutes to obtain a rubber compound; S2. Extrusion vulcanization: transfer the rubber material to a vulcanizer and vulcanize it at 160-170°C for 20-30 minutes, then leave it for 20-24 hours to obtain an outer sheath layer, which is then extruded and coated on the surface of the conductor core through a twin-screw extruder to obtain an aging-resistant overhead cable.

10. The method for preparing an aging-resistant overhead cable according to claim 9, characterized in that: The mixing temperature is 122-126°C; the extrusion temperature of the twin-screw extruder is 170-180°C.

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