High performance polypropylene cable material and process for its preparation

Abstract

The application provides a high-performance polypropylene cable material and a preparation method thereof, and belongs to the technical field of polypropylene cable materials.The polypropylene cable material comprises the following raw materials: polypropylene, a master batch, PP-g-MAH, Tinuvin 622, antioxidant 1010, antioxidant 168 and zinc stearate.The master batch comprises the following raw materials: polypropylene, PP-g-MAH, a composite hybrid material, antioxidant 1010, antioxidant 168 and zinc stearate.The composite hybrid material is prepared by modifying modified magnesium oxide and modified carbon nanotubes deposited with silver as a matrix, stirring in dark under the action of hydrochloric acid dopamine, and modifying 4,4'-dihydroxymethyl glycidyl oxydiphenyl, 4-amino-2,2,6,6-tetramethylpiperidine and nitroxide free radical piperidinol.The polypropylene cable material prepared by the preparation method has high heat conduction performance and insulation performance.

Description

Technical Field

[0001] This invention belongs to the field of polypropylene cable material technology, and in particular relates to a high-performance polypropylene cable material and its preparation method. Background Technology

[0002] Polypropylene (PP), with its low density, non-toxicity, excellent processing performance, and balanced mechanical properties, has become a key material widely used in cable insulation sheathing. However, conventional PP materials have poor thermal conductivity, causing the heat generated by the cable during operation to be unable to dissipate effectively and promptly. Prolonged exposure to high-temperature environments not only significantly accelerates the aging process of PP materials but also affects the cable's conductivity, thus shortening its overall service life. More importantly, current modification methods for improving PP performance often struggle to achieve an ideal balance between thermal conductivity and insulation. Some modification methods aimed at enhancing thermal conductivity often sacrifice the material's insulation resistance, which undoubtedly affects the safety and reliability of the cable, making it unsuitable for applications with stringent performance requirements, such as high-voltage cables.

[0003] Chinese patent application CN113861559A discloses a thermally conductive polypropylene material, its preparation method, and its application. The thermally conductive polypropylene material comprises the following components by weight: 60-83 parts of a first polypropylene resin, 4-10 parts of a second polypropylene resin, 2-10 parts of a polyethylene resin, 1-5 parts of a compatibilizer, 3-8 parts of foam metal, 10-20 parts of a thermally conductive filler, and 0.2-1 parts of a passivating agent. This application modifies the polypropylene material by simultaneously adding foam metal, thermally conductive filler, and meltblown polypropylene. The synergistic effect of these three components not only significantly improves the material's thermal conductivity but also achieves lightweighting, while simultaneously possessing superior electrical insulation and mechanical properties. Although this patent can improve thermal conductivity and lightweighting to a certain extent and claims to have superior electrical insulation properties, in reality, the material's thermal conductivity and insulation properties are mutually restrictive. Increasing the amount of foam metal can enhance thermal conductivity but easily forms conductive pathways, reducing insulation; reducing the amount results in insufficient thermal network construction, and the improvement in thermal conductivity has a clear upper limit. Therefore, developing a high-performance polypropylene cable material that can simultaneously possess high thermal conductivity and high insulation is of great practical significance and application value for ensuring the safe and stable operation of the power system. Summary of the Invention

[0004] This invention provides a high-performance polypropylene cable material and its preparation method, overcoming the shortcomings of the prior art and effectively improving the thermal conductivity and insulation performance of the finished polypropylene cable material.

[0005] The technical solution of the present invention is achieved through the following measures: The first aspect of this invention provides a high-performance polypropylene cable material, comprising the following raw materials in parts by weight: Polypropylene 70-75 parts by weight, masterbatch 16-20 parts by weight, PP-g-MAH 5-5.5 parts by weight, Tinuvin 622 0.25-0.3 parts by weight, antioxidant 1010 0.3-0.5 parts by weight, antioxidant 168 0.15-0.2 parts by weight, zinc stearate 0.1-0.15 parts by weight; The masterbatch comprises the following raw materials in parts by weight: 70-72 parts by weight of polypropylene, 5.5-6 parts by weight of PP-g-MAH, 15-18 parts by weight of composite hybrid, 0.8-1 parts by weight of antioxidant 1010, 0.4-0.6 parts by weight of antioxidant 168, and 0.6-1 parts by weight of zinc stearate; The composite hybrid material is prepared by stirring with dopamine hydrochloride in the dark, and then modifying it with 4,4'-diglycidoxybiphenyl, 4-amino-2,2,6,6-tetramethylpiperidine and nitroxide free radical piperinol.

[0006] This invention constructs a thermally conductive network by depositing silver on the surface of magnesium oxide and combining it with polydopamine formed by the self-polymerization of dopamine hydrochloride, thus bonding modified magnesium oxide and modified carbon nanotubes into a core-shell composite hybrid. Simultaneously, magnesium oxide provides shallow traps, while polydopamine, 4,4'-diglycidoxybiphenyl, and 4-amino-2,2,6,6-tetramethylpiperidine form gradient deep traps, effectively suppressing carrier migration and space charge accumulation. Furthermore, nitroxide free radical piperidinol and Tinuvin 622 synergistically resist thermo-oxidative and photo-oxidative aging. This achieves high insulation and high thermal conductivity in polypropylene cable materials.

[0007] As a preferred embodiment of the present invention, the specific preparation method of the modified magnesium oxide includes the following steps: Magnesium oxide and anhydrous ethanol were mixed and ultrasonically dispersed, then centrifuged and dried to obtain pretreated magnesium oxide. Pretreated magnesium oxide and N,N-dimethylformamide were mixed and ultrasonically dispersed, polyvinylpyrrolidone was added and stirred, silver nitrate solution was added dropwise under nitrogen atmosphere, the temperature was raised and the stirring speed was controlled, cooled, centrifuged, washed and dried to obtain dry intermediate material; The dried intermediate material was added to an ethanol solution, the pH was adjusted, and silane coupling agent KH-560 was added dropwise under reflux and stirring. After centrifugation, washing, and drying, modified magnesium oxide was obtained.

[0008] This invention uses N,N-dimethylformamide as a reducing agent and solvent to uniformly deposit silver nitrate on the surface of magnesium oxide, forming a relatively continuous thermally conductive path. At this time, magnesium oxide provides a highly insulating substrate and good thermal conductivity, while silver acts as a "thermally conductive solder joint" to promote the formation of thermally conductive channels and to some extent compensate for possible thermal breakpoints between adjacent magnesium oxide particles, significantly reducing interfacial thermal resistance and phonon scattering. At the same time, the modification of the silane coupling agent KH-560 further isolates the modified magnesium oxide, reducing the formation of conductive channels, and achieving a synergistic improvement in insulation and thermal conductivity.

[0009] Furthermore, in the preparation process of pretreated magnesium oxide: the ratio of magnesium oxide to anhydrous ethanol is 8.5-10g:100-120mL; In the preparation of the dried intermediate material: the ratio of the pretreated magnesium oxide, N,N-dimethylformamide, polyvinylpyrrolidone, and silver nitrate solution is 9-10g:500-540mL:2-2.4g:0.34-0.4g; In the preparation of modified magnesium oxide: the ratio of the dry intermediate material, ethanol solution and silane coupling agent KH-560 is 9-10g:400-420mL:0.3-0.5g.

[0010] Furthermore, the concentration of the silver nitrate solution is 0.1-0.2 mol / L.

[0011] Furthermore, in the preparation process of pretreated magnesium oxide: the ultrasonic dispersion power is 200-220W and the time is 20-30min; the centrifugation speed is 6000-8000rpm and the time is 10-15min; the drying temperature is 55-60℃ and the time is 8-10h. In the preparation of the dried intermediate material: the ultrasonic dispersion time is 30-35 min; the stirring time for adding polyvinylpyrrolidone is 20-30 min; the temperature-controlled stirring is carried out by heating to 65-70℃ and stirring at 250-300 rpm for 3-4 h; the centrifugation speed is 6000-8000 rpm and the time is 8-10 min; the washing is carried out by washing 2-3 times each with anhydrous ethanol and deionized water preheated to 45-50℃; the drying temperature is 55-60℃ and the time is 6-8 h. In the preparation process of modified magnesium oxide: the pH is adjusted to 4-4.5 using glacial acetic acid; the reflux stirring temperature is 55-60℃ and the time is 1.5-2h; the centrifugation speed is 5500-6000rpm and the time is 8-10min; the washing is performed 2-3 times with anhydrous ethanol; and the drying temperature is 55-60℃ and the time is 8-10h.

[0012] Furthermore, the volume concentration of the ethanol solution is 90-95 wt%.

[0013] As a preferred embodiment of the present invention, the specific preparation method of the modified carbon nanotubes includes the following steps: The mixture and multi-walled carbon nanotubes were mixed and sonicated, centrifuged, washed and dried to obtain acidified carbon nanotubes. The acidified carbon nanotubes were mixed with an ethanol solution, the pH was adjusted, the mixture was ultrasonically dispersed, and silane coupling agent KH-550 was added dropwise under reflux and stirring. The mixture was then centrifuged, washed, and dried to obtain modified carbon nanotubes.

[0014] Furthermore, in the preparation process of acidified carbon nanotubes: the ratio of the mixture to multi-walled carbon nanotubes is 250-270 mL: 4.5-5 g; In the preparation of modified carbon nanotubes: the ratio of the acidified carbon nanotubes, ethanol solution and silane coupling agent KH-550 is 5-5.5g:300-350mL:0.25-0.3g.

[0015] Furthermore, the mixture comprises concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 2.8-3:1, and the ethanol solution has a volume concentration of 90-95 wt%.

[0016] Furthermore, in the preparation process of acidified carbon nanotubes: the ultrasonic power is 150-160W, the temperature is 65-70℃, and the time is 2-3h; the centrifugation speed is 6000-8000rpm, and the time is 10-15min; the washing is performed with deionized water until the pH of the filtrate is 6.5-7.0; the drying temperature is 55-60℃, and the time is 8-10h. In the preparation process of modified carbon nanotubes: the pH is adjusted to 4-4.5 using glacial acetic acid; the ultrasonic power is 250-300W for 50-60 min; the reflux stirring temperature is 55-60℃ for 1.5-2 h; the centrifugation speed is 6000-8000 rpm for 8-10 min; the washing is performed 2-3 times with anhydrous ethanol; and the drying temperature is 70-80℃ for 6-8 h.

[0017] As a preferred embodiment of the present invention, the specific preparation method of the composite hybrid material includes the following steps: Tris-HCl buffer, modified magnesium oxide and modified carbon nanotubes were mixed and ultrasonically dispersed, dopamine hydrochloride was added and stirred in the dark, centrifuged, washed and dried to obtain intermediate modified material; N,N-dimethylformamide was preheated, and 4,4'-diglycidyloxybiphenyl and intermediate modified material were added and ultrasonically dispersed. Triethylamine was then added and stirred under controlled temperature. After cooling, 4-amino-2,2,6,6-tetramethylpiperidine was added dropwise and stirred in the dark for the first time. Nitrogen oxide free radical piperidinol was added and stirred in the dark for the second time. After cooling, centrifugation, washing, and drying, the composite hybrid material was obtained.

[0018] Under weakly alkaline conditions, dopamine hydrochloride undergoes oxidative self-polymerization to generate polydopamine, effectively bonding modified carbon nanotubes treated with KH-550 and modified magnesium oxide treated with KH-560 to construct a composite hybrid material with a core-shell multi-level structure. In this composite hybrid material, modified magnesium oxide acts as a node, modified carbon nanotubes act as a bridge to provide a heat conduction path, while polydopamine plays a connecting role and reduces the interfacial thermal resistance of the system, enabling modified magnesium oxide and modified carbon nanotubes to form a stable composite hybrid thermally conductive material. Therefore, adding the composite hybrid material to the system can significantly improve the thermal conductivity of cable material particles, showing obvious advantages compared to single filler systems. In addition, magnesium oxide can form a large number of shallow traps in the matrix, which enhances the carrier diffusion ability and prevents local charge accumulation. The catechol or quinone structure and π electron conjugation system in the polydopamine layer on the surface of the composite hybrid material can provide deeper traps to capture migrating carriers. 4,4'-diglycidoxybiphenyl provides a local barrier with its rigid benzene ring structure, which increases the tortuosity of the carrier diffusion path. The lone pair electrons in 4-amino-2,2,6,6-tetramethylpiperidine can capture injected electrons. The obstructed space structure forms a deep and stable electron trap, which further suppresses the accumulation of space charge, thereby greatly improving the insulation performance of the finished product. Nitrogen oxide free radical piperidinol can bond to the shell surface of the system to form local antioxidant protection, and quickly capture alkyl and peroxide free radicals generated by thermo-oxidative aging. At the same time, compared with adding it in the subsequent cable material preparation process, adding nitroxide free radical piperidinol at this time can avoid the problems of subsequent migration and precipitation and poor long-term effectiveness.

[0019] Furthermore, in the preparation of the intermediate modified material: the ratio of the Tris-HCl buffer solution, modified magnesium oxide, modified carbon nanotubes and dopamine hydrochloride is 500-520mL:9.5-10g:0.7-1g:0.7-1.0g; In the preparation of the composite hybrid material: the ratio of N,N-dimethylformamide, 4,4'-diglycidoxybiphenyl, intermediate modifier, triethylamine, 4-amino-2,2,6,6-tetramethylpiperidine and nitroxide free radical piperidinol is 200-230mL:1.8-2g:10-10.7g:0.2-0.25mL:0.5-0.6g:0.15-0.18g.

[0020] Furthermore, in the preparation process of the intermediate modified material: The ultrasonic dispersion is performed at a power of 180-200W for 60-70 minutes; the light-protected stirring is performed at a speed of 280-300 rpm for 12-15 hours; the centrifugation is performed at a speed of 7000-8000 rpm for 10-15 minutes; and the drying is performed under vacuum at 55-60°C for 20-24 hours. In the preparation process of composite hybrid materials: The preheating temperature is 55-60℃; the ultrasonic dispersion time is 20-30 min; the temperature for temperature-controlled stirring is 75-80℃ for 3-3.5 h; the cooling temperature is 60-70℃; the first stirring in the dark is 60-65℃ for 3-3.5 h; the heating temperature is 68-72℃; the second stirring in the dark is 2-2.5 h; the cooling temperature is room temperature; the centrifugation speed is 6000-8000 rpm for 8-10 min; the washing process involves washing 2-3 times each with N,N-dimethylformamide and anhydrous ethanol, then washing with deionized water until neutral, and finally washing 2-3 times with anhydrous ethanol; the drying process involves vacuum drying at 55-60℃ for 8-10 h.

[0021] Furthermore, the Tris-HCl buffer is a 10mM Tris-HCl buffer with pH=8.5.

[0022] A second aspect of this invention provides a method for preparing a high-performance polypropylene cable material, comprising the following steps: (1) Preparation of masterbatch: Polypropylene, PP-g-MAH, composite hybrid material, antioxidant 1010, antioxidant 168 and zinc stearate are mixed evenly, and then melt-extruded, cooled and pelletized by twin-screw extruder to obtain masterbatch; (2) Preparation of cable material particles: Polypropylene, the masterbatch obtained in step (1), PP-g-MAH, Tinuvin 622, antioxidant 1010, antioxidant 168 and zinc stearate are mixed evenly, and then melt-extruded, cooled and pelletized by twin-screw extruder to obtain cable material particles. (3) Preparation of cable material: The cable material particles are extruded through a die in an extruder and coated on the outside of the conductor. After cooling, shaping and winding, the cable material is obtained.

[0023] This invention first prepares the composite hybrid material into masterbatch, and then blends it with raw materials such as polypropylene matrix, PP-g-MAH, Tinuvin 622 and antioxidants. This ensures the uniform dispersion of the composite hybrid material in the system and further ensures the stability of the insulation and thermal conductivity of the cable material, making it suitable for the continuous production of high-performance cables.

[0024] As a preferred technical solution of the present invention, the temperatures of each section of the twin-screw extruder from the feeding section to the die head section in step (1) are as follows: 75-80℃, 150-160℃, 170-180℃, 190-195℃, 195-200℃, 200-205℃, 200-205℃, 195-200℃, 190-195℃, 190-195℃; the screw speed of the twin-screw extruder is 230-250 rpm.

[0025] As a preferred technical solution of the present invention, the temperatures of each section of the twin-screw extruder from the feeding section to the die head section in step (2) are as follows: 75-80℃, 165-170℃, 180-190℃, 190-200℃, 200-205℃, 200-205℃, 195-200℃, 190-195℃, 190-195℃; the screw speed of the twin-screw extruder is 260-280 rpm.

[0026] As a preferred technical solution of the present invention, the conductor in step (3) includes, but is not limited to, copper core wire or aluminum core wire.

[0027] The beneficial effects of this invention are: (1) In this invention, silver is deposited on the surface of magnesium oxide. Magnesium oxide provides a high insulating substrate and good thermal conductivity, while silver acts as a "thermal conductive solder joint" to promote the formation of thermal conductive channels and to a certain extent compensate for the possible thermal conductivity breaks between adjacent magnesium oxide particles. The modification of silane coupling agent KH-560 further isolates the modified magnesium oxide, reduces the formation of conductive channels, and achieves a synergistic improvement in the insulation and thermal conductivity of magnesium oxide. At the same time, this invention also adds dopamine hydrochloride to the system to oxidize and self-polymerize into polydopamine, which bonds the modified carbon nanotubes and modified magnesium oxide to construct a multi-level core-shell composite hybrid material, which significantly improves the thermal conductivity of the obtained cable material and has obvious advantages compared with a single filler system.

[0028] (2) Magnesium oxide can form shallow traps in the matrix, the polydopamine layer on the surface of the composite hybrid material can provide deeper traps to capture migrating charge carriers, 4,4'-diglycidoxybiphenyl can increase the tortuosity of the charge carrier diffusion path, and 4-amino-2,2,6,6-tetramethylpiperidine can form deep stable electron traps to further suppress space charge accumulation. Therefore, the cable material made in this way can have excellent insulation properties.

[0029] (3) The present invention innovatively incorporates nitroxide free radical piperidinol to rapidly capture alkyl and peroxide free radicals generated by thermo-oxidative aging, and disperses Tinuvin 622 inside the polypropylene matrix to provide ultraviolet absorption and capture of free radicals generated by ultraviolet photoaging, thus providing long-term protection for the matrix. Therefore, nitroxide free radical piperidinol and Tinuvin 622 can provide anti-aging protection to maintain the stability of long-term insulation and thermal conductivity. Detailed Implementation

[0030] The present invention is not limited to the following embodiments, and the specific implementation can be determined according to the technical solution of the present invention and the actual situation.

[0031] The polypropylene used in this invention, model HP510M, was purchased from CNOOC Shell Petrochemicals Co., Ltd. The PP-g-MAH used, model: CMG9801, was purchased from: Jia Yi Rong Polymer (Shanghai) Co., Ltd. The magnesium oxide used, model: ZH-MgO50N, with an average particle size (nm) of 50, was purchased from Anhui Zhonghang Nanotechnology Development Co., Ltd. The multi-walled carbon nanotubes used had a diameter of 10-20 nm, item number 100252, and were purchased from Jiangsu Xianfeng Nanomaterials Technology Co., Ltd. The Tinuvin 622 used was purchased from Wuhan Jinqu New Materials Co., Ltd. The above will not be repeated hereafter.

[0032] The present invention will be further described below with reference to embodiments: Preparation Example 1 This preparation example demonstrates the preparation of a composite hybrid material using the following steps: S1. Mix 9.3g of magnesium oxide and 110mL of anhydrous ethanol, then ultrasonically disperse at 200W for 20min, centrifuge at 7000rpm for 10min, and then dry at 55℃ for 8h to obtain pretreated magnesium oxide. 9g of pretreated magnesium oxide and 520mL of N,N-dimethylformamide were mixed and ultrasonically dispersed for 30min. 2g of polyvinylpyrrolidone was added and stirred for 20min. 0.34g of 0.1mol / L silver nitrate solution was added dropwise under nitrogen atmosphere. The mixture was heated to 65℃ and stirred at 300rpm for 3h. After cooling to room temperature, it was centrifuged at 7500rpm for 8min. The mixture was washed twice with anhydrous ethanol and twice with deionized water preheated to 45℃. It was then dried at 55℃ for 7.5h to obtain the dried intermediate material. Take 9g of dried intermediate material and add it to 400mL of 90wt% ethanol solution. Adjust the pH to 4.1 with glacial acetic acid. Add 0.4g of silane coupling agent KH-560 and reflux at 60℃ for 1.5h. Centrifuge at 5750rpm for 8min. Wash twice with anhydrous ethanol and dry at 60℃ for 9h to obtain modified magnesium oxide. S2. Mix 265 mL of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 2.8:1 with 4.5 g of multi-walled carbon nanotubes, sonicate at 66 °C for 3 h at 150 W power, centrifuge at 7000 rpm for 10 min, wash with deionized water until the pH of the filtrate is 6.5, and dry at 55 °C for 10 h to obtain acidified carbon nanotubes. 5g of acidified carbon nanotubes were mixed with 300mL of 90wt% ethanol solution, the pH was adjusted to 4.1 with glacial acetic acid, and the mixture was ultrasonically dispersed at 250W for 50min. 0.3g of silane coupling agent KH-550 was added dropwise and refluxed at 55℃ for 1.5h. The mixture was then centrifuged at 6000rpm for 8min, washed three times with anhydrous ethanol, and dried at 70℃ for 7.5h to obtain modified carbon nanotubes. S3. Mix 500 mL of 10 mM Tris-HCl buffer (pH=8.5), 9.7 g of modified magnesium oxide and 0.85 g of modified carbon nanotubes, and ultrasonically disperse at 180 W for 60 min. Add 0.7 g of dopamine hydrochloride, stir at 280 rpm in the dark for 12 h, centrifuge at 7000 rpm for 10 min, take the precipitate, wash it three times with deionized water, and vacuum dry at 55 ℃ for 23 h to obtain the intermediate modified material. Preheat 200 mL of N,N-dimethylformamide to 57.5 °C, add 1.95 g of 4,4'-diglycidyloxybiphenyl and 10.7 g of intermediate modifier, and ultrasonically disperse for 20 min. Then add 0.2 mL of triethylamine and stir at 75 °C for 3 h. Cool down to 60 °C, add 0.5 g of 4-amino-2,2,6,6-tetramethylpiperidine, and stir for the first time in the dark at 60 °C for 3 h. Raise the temperature to 68 °C, add 0.15 g of nitric oxide free radical piperidinol, and stir for the second time in the dark for 2 h. Cool to room temperature, centrifuge at 6000 rpm for 8 min, and take the precipitate. Wash it three times each with N,N-dimethylformamide and anhydrous ethanol, then wash it with deionized water until neutral, and finally wash it twice with anhydrous ethanol. Dry it under vacuum at 55 °C for 9 h to obtain the composite hybrid material.

[0033] Preparation Example 2 This preparation example demonstrates the preparation of a composite hybrid material using the following steps: S1. Mix 8.5g of magnesium oxide and 100mL of anhydrous ethanol, then ultrasonically disperse at 210W for 25min, centrifuge at 6000rpm for 12min, and then dry at 57.5℃ for 9h to obtain pretreated magnesium oxide. 9.3g of pretreated magnesium oxide and 500mL of N,N-dimethylformamide were mixed and ultrasonically dispersed for 31min. 2.3g of polyvinylpyrrolidone was added and stirred for 25min. 0.39g of 0.2mol / L silver nitrate solution was added dropwise under nitrogen atmosphere. The mixture was heated to 68℃ and stirred at 250rpm for 3h. After cooling to room temperature, it was centrifuged at 6000rpm for 8min. The mixture was washed three times each with anhydrous ethanol and preheated to 50℃ deionized water. It was then dried at 60℃ for 6.5h to obtain the dried intermediate material. Take 9.5g of dried intermediate material and add it to 415mL of 95wt% ethanol solution. Adjust the pH to 4.3 with glacial acetic acid. Add 0.3g of silane coupling agent KH-560 dropwise and reflux at 57.5℃ for 2h. Centrifuge at 5500rpm for 9min. Wash three times with anhydrous ethanol and dry at 55℃ for 10h to obtain modified magnesium oxide. S2. Mix 255 mL of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1 with 4.9 g of multi-walled carbon nanotubes, sonicate at 155 W power and 65 °C for 3 h, centrifuge at 6000 rpm for 15 min, wash with deionized water until the pH of the filtrate is 7.0, and dry at 60 °C for 9.5 h to obtain acidified carbon nanotubes. 5.4 g of acidified carbon nanotubes were mixed with 325 mL of 90 wt% ethanol solution, the pH was adjusted to 4.0 with glacial acetic acid, and the mixture was ultrasonically dispersed at 275 W for 55 min. 0.25 g of silane coupling agent KH-550 was added dropwise and refluxed at 60 °C for 2 h. The mixture was then centrifuged at 7000 rpm for 8 min, washed three times with anhydrous ethanol, and dried at 78 °C for 6 h to obtain modified carbon nanotubes. S3. Mix 515 mL of 10 mM Tris-HCl buffer (pH=8.5), 9.6 g of modified magnesium oxide and 0.93 g of modified carbon nanotubes, and ultrasonically disperse at 180 W for 65 min. Add 0.93 g of dopamine hydrochloride, stir at 295 rpm in the dark for 14 h, centrifuge at 7750 rpm for 10 min, take the precipitate, wash twice with deionized water, and vacuum dry at 55 °C for 24 h to obtain intermediate modified material. 223 mL of N,N-dimethylformamide was preheated to 55 °C. 1.85 g of 4,4'-diglycidyloxybiphenyl and 10.2 g of intermediate modifier were added and ultrasonically dispersed for 25 min. Then, 0.25 mL of triethylamine was added and stirred at 75 °C for 3.5 h. The mixture was then cooled to 65 °C, and 0.55 g of 4-amino-2,2,6,6-tetramethylpiperidine was added dropwise and stirred for 3.5 h in the dark at 60 °C. The mixture was then heated to 71 °C, and 0.17 g of nitric oxide free radical piperidinol was added and stirred for 2.5 h in the dark. The mixture was cooled to room temperature and centrifuged at 7000 rpm for 9 min. The precipitate was washed three times each with N,N-dimethylformamide and anhydrous ethanol, then washed with deionized water until neutral, and finally washed three times with anhydrous ethanol. The mixture was then vacuum dried at 57.5 °C for 8 h to obtain the composite hybrid material.

[0034] Preparation Example 3 This preparation example demonstrates the preparation of a composite hybrid material using the following steps: S1. Mix 9.6g of magnesium oxide and 120mL of anhydrous ethanol, then ultrasonically disperse at 210W for 25min, centrifuge at 7500rpm for 10min, and then dry at 55℃ for 9h to obtain pretreated magnesium oxide. 9.5g of pretreated magnesium oxide and 530mL of N,N-dimethylformamide were mixed and ultrasonically dispersed for 32min. 2.1g of polyvinylpyrrolidone was added and stirred for 25min. 0.36g of 0.2mol / L silver nitrate solution was added dropwise under nitrogen atmosphere. The mixture was heated to 67℃ and stirred at 275rpm for 3.5h. After cooling to room temperature, it was centrifuged at 7000rpm for 9min. The mixture was washed twice with anhydrous ethanol and twice with deionized water preheated to 47℃. It was then dried at 56℃ for 6h to obtain the dried intermediate material. Take 9.3g of dried intermediate material and add it to 405mL of 90wt% ethanol solution. Adjust the pH to 4.5 with glacial acetic acid. Add 0.5g of silane coupling agent KH-560 dropwise and reflux at 57.5℃ for 1.5h. Centrifuge at 5800rpm for 9min. Wash three times with anhydrous ethanol and dry at 57℃ for 8h to obtain modified magnesium oxide. S2. Mix 250 mL of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1 with 4.6 g of multi-walled carbon nanotubes, sonicate at 70 °C for 2 h at 155 W power, centrifuge at 7500 rpm for 12.5 min, wash with deionized water until the pH of the filtrate is 6.5, and dry at 57.5 °C for 8 h to obtain acidified carbon nanotubes. 5.2 g of acidified carbon nanotubes were mixed with 325 mL of 93 wt% ethanol solution, the pH was adjusted to 4.4 with glacial acetic acid, and the mixture was ultrasonically dispersed at 300 W for 60 min. 0.28 g of silane coupling agent KH-550 was added dropwise, and the mixture was refluxed and stirred at 57.5 °C for 1.5 h. The mixture was then centrifuged at 7500 rpm for 9 min, washed twice with anhydrous ethanol, and dried at 75 °C for 7 h to obtain modified carbon nanotubes. S3. Mix 510 mL of 10 mM Tris-HCl buffer (pH=8.5), 9.5 g of modified magnesium oxide and 0.7 g of modified carbon nanotubes, and ultrasonically disperse at 190 W for 65 min. Add 0.78 g of dopamine hydrochloride, stir at 290 rpm in the dark for 12 h, centrifuge at 7250 rpm for 12 min, take the precipitate, wash twice with deionized water, and vacuum dry at 57.5 ℃ for 20 h to obtain intermediate modified material. Preheat 230 mL of N,N-dimethylformamide to 57.5 °C, add 1.8 g of 4,4'-diglycidyloxybiphenyl and 10.4 g of intermediate modifier, and ultrasonically disperse for 25 min. Then add 0.23 mL of triethylamine and stir at 77.5 °C for 3 h. Cool down to 65 °C, add 0.55 g of 4-amino-2,2,6,6-tetramethylpiperidine, and stir for the first time in the dark at 62.5 °C for 3 h. Raise the temperature to 70 °C, add 0.16 g of nitric oxide free radical piperidinol, and stir for the second time in the dark for 2 h. Cool to room temperature, centrifuge at 6500 rpm for 8 min, and take the precipitate. Wash twice each with N,N-dimethylformamide and anhydrous ethanol, then wash with deionized water until neutral, and finally wash three times with anhydrous ethanol. Dry under vacuum at 57.5 °C for 8.5 h to obtain the composite hybrid material.

[0035] Preparation Example 4 This preparation example demonstrates the preparation of a composite hybrid material using the following steps: S1. Mix 8.9g of magnesium oxide and 105mL of anhydrous ethanol, then ultrasonically disperse at 220W for 30min, centrifuge at 8000rpm for 15min, and then dry at 60℃ for 10h to obtain pretreated magnesium oxide. 9.7g of pretreated magnesium oxide and 510mL of N,N-dimethylformamide were mixed and ultrasonically dispersed for 34min. 2.4g of polyvinylpyrrolidone was added and stirred for 28min. 0.4g of 0.1mol / L silver nitrate solution was added dropwise under nitrogen atmosphere. The mixture was heated to 70℃ and stirred at 275rpm for 4h. After cooling to room temperature, it was centrifuged at 6500rpm for 9min. The mixture was washed three times each with anhydrous ethanol and preheated to 46℃ deionized water. It was then dried at 59℃ for 7h to obtain the dried intermediate material. Take 10g of dried intermediate material and add it to 420mL of 95wt% ethanol solution. Adjust the pH to 4.2 with glacial acetic acid. Add 0.35g of silane coupling agent KH-560 and reflux at 55℃ for 2h. Centrifuge at 5600rpm for 10min. Wash twice with anhydrous ethanol and dry at 60℃ for 8.5h to obtain modified magnesium oxide. S2. Mix 260 mL of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 2.9:1 with 5 g of multi-walled carbon nanotubes, sonicate at 67 °C for 2 h at 160 W power, centrifuge at 8000 rpm for 10 min, wash with deionized water until the pH of the filtrate is 6.8, and dry at 55 °C for 8.5 h to obtain acidified carbon nanotubes. 5.5g of acidified carbon nanotubes were mixed with 350mL of 95wt% ethanol solution, the pH was adjusted to 4.5 with glacial acetic acid, and the mixture was ultrasonically dispersed at 300W for 55min. 0.29g of silane coupling agent KH-550 was added dropwise and refluxed at 60℃ for 2h. The mixture was then centrifuged at 6500rpm for 9min, washed three times with anhydrous ethanol, and dried at 75℃ for 6.5h to obtain modified carbon nanotubes. S3. Mix 505 mL of 10 mM Tris-HCl buffer (pH=8.5), 9.9 g of modified magnesium oxide and 0.78 g of modified carbon nanotubes, and sonicate at 200 W for 67 min. Add 1.0 g of dopamine hydrochloride, stir at 285 rpm in the dark for 13 h, centrifuge at 8000 rpm for 15 min, take the precipitate, wash it three times with deionized water, and vacuum dry it at 60 ℃ for 21 h to obtain the intermediate modified material. Preheat 207 mL of N,N-dimethylformamide to 60 °C, add 1.9 g of 4,4'-diglycidyloxybiphenyl and 10.5 g of intermediate modifier, and ultrasonically disperse for 30 min. Then add 0.21 mL of triethylamine and stir at 80 °C for 3.5 h. Cool down to 60 °C, add 0.6 g of 4-amino-2,2,6,6-tetramethylpiperidine, and stir for 3.5 h in the dark at 65 °C for the first time. Raise the temperature to 69 °C, add 0.17 g of nitric oxide free radical piperidinol, and stir for 2.5 h in the dark for the second time. Cool to room temperature, centrifuge at 8000 rpm for 9 min, and take the precipitate. Wash it three times each with N,N-dimethylformamide and anhydrous ethanol, then wash it with deionized water until neutral, and finally wash it twice with anhydrous ethanol. Dry it under vacuum at 55 °C for 10 h to obtain the composite hybrid material.

[0036] Preparation Example 5 This preparation example demonstrates the preparation of a composite hybrid material using the following steps: S1. Mix 10g of magnesium oxide and 115mL of anhydrous ethanol, then ultrasonically disperse at 220W for 30min, centrifuge at 6500rpm for 15min, and then dry at 60℃ for 10h to obtain pretreated magnesium oxide. 10g of pretreated magnesium oxide and 540mL of N,N-dimethylformamide were mixed and ultrasonically dispersed for 35min. 2.2g of polyvinylpyrrolidone was added and stirred for 30min. 0.37g of 0.2mol / L silver nitrate solution was added dropwise under nitrogen atmosphere. The mixture was heated to 67℃ and stirred at 300rpm for 4h. After cooling to room temperature, it was centrifuged at 8000rpm for 10min. The mixture was washed three times each with anhydrous ethanol and preheated to 49℃ deionized water. It was then dried at 57℃ for 8h to obtain the dried intermediate material. Take 9.8g of dried intermediate material and add it to 410mL of 95wt% ethanol solution. Adjust the pH to 4.5 with glacial acetic acid. Add 0.45g of silane coupling agent KH-560 dropwise and reflux at 60℃ for 2h. Centrifuge at 6000rpm for 10min. Wash three times with anhydrous ethanol and dry at 60℃ for 9.5h to obtain modified magnesium oxide. S2. Mix 270 mL of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1 with 4.8 g of multi-walled carbon nanotubes, sonicate at 68 °C for 2.5 h at 160 W power, centrifuge at 6500 rpm for 15 min, wash with deionized water until the pH of the filtrate is 7.0, and dry at 60 °C for 9 h to obtain acidified carbon nanotubes. 5.3 g of acidified carbon nanotubes were mixed with 350 mL of 95 wt% ethanol solution, the pH was adjusted to 4.3 with glacial acetic acid, and the mixture was ultrasonically dispersed at 275 W for 58 min. 0.26 g of silane coupling agent KH-550 was added dropwise and refluxed at 60 °C for 2 h. The mixture was then centrifuged at 8000 rpm for 10 min, washed twice with anhydrous ethanol, and dried at 80 °C for 8 h to obtain modified carbon nanotubes. S3. Mix 520 mL of 10 mM Tris-HCl buffer (pH=8.5), 10 g of modified magnesium oxide and 1 g of modified carbon nanotubes, and sonicate at 200 W for 70 min. Add 0.85 g of dopamine hydrochloride, stir at 300 rpm in the dark for 15 h, centrifuge at 7500 rpm for 15 min, take the precipitate, wash it three times with deionized water, and vacuum dry it at 60 ℃ for 22 h to obtain the intermediate modified material. Preheat 215 mL of N,N-dimethylformamide to 60 °C, add 2 g of 4,4'-diglycidyloxybiphenyl and 10 g of intermediate modifier, and ultrasonically disperse for 30 min. Then add 0.24 mL of triethylamine and stir at 80 °C for 3.5 h. Cool down to 70 °C, add 0.6 g of 4-amino-2,2,6,6-tetramethylpiperidine, and stir for the first time in the dark at 65 °C for 3.5 h. Raise the temperature to 72 °C, add 0.18 g of nitric oxide free radical piperidinol, and stir for the second time in the dark for 2.5 h. Cool to room temperature, centrifuge at 7500 rpm for 10 min, and take the precipitate. Wash twice each with N,N-dimethylformamide and anhydrous ethanol, then wash with deionized water until neutral, and finally wash three times with anhydrous ethanol. Dry under vacuum at 60 °C for 9.5 h to obtain the composite hybrid material.

[0037] Example 1 (1) Preparation of masterbatch: 70 parts by weight of polypropylene, 5.5 parts by weight of PP-g-MAH, 15 parts by weight of the composite hybrid material prepared in Example 5, 0.8 parts by weight of antioxidant 1010, 0.4 parts by weight of antioxidant 168 and 0.6 parts by weight of zinc stearate were mixed evenly and then melted, extruded, cooled and pelletized in a twin-screw extruder with the following temperatures from the feeding section to the die head section: 75℃, 150℃, 175℃, 190℃, 195℃, 200℃, 200℃, 195℃, 190℃ and 190℃ respectively, and the screw speed was 230 rpm. (2) Preparation of cable material particles: 70 parts by weight of polypropylene, 19 parts by weight of the masterbatch obtained in step (1), 5.3 parts by weight of PP-g-MAH, 0.25 parts by weight of Tinuvin 622, 0.3 parts by weight of antioxidant 1010, 0.15 parts by weight of antioxidant 168 and 0.1 parts by weight of zinc stearate are mixed and then melted, extruded, cooled and pelletized in a twin-screw extruder with the following temperatures from the feeding section to the die head section: 75℃, 165℃, 180℃, 190℃, 200℃, 200℃, 195℃, 190℃, 190℃, and screw speed of 260 rpm. (3) Preparation of cable material: The cable material particles are extruded through a die in an extruder and coated on the outside of the conductor. After cooling, shaping and winding, the cable material is obtained.

[0038] Example 2 (1) Preparation of masterbatch: 71.5 parts by weight of polypropylene, 5.7 parts by weight of PP-g-MAH, 16 parts by weight of the composite hybrid material prepared in Example 2, 1 part by weight of antioxidant 1010, 0.4 parts by weight of antioxidant 168 and 0.9 parts by weight of zinc stearate were mixed evenly and then melted, extruded, cooled and pelletized in a twin-screw extruder with the following temperatures from the feeding section to the die head section: 80℃, 155℃, 170℃, 195℃, 200℃, 200℃, 205℃, 200℃, 190℃ and 190℃ respectively, and the screw speed was 240 rpm. (2) Preparation of cable material particles: 73 parts by weight of polypropylene, 16 parts by weight of the masterbatch obtained in step (1), 5 parts by weight of PP-g-MAH, 0.3 parts by weight of Tinuvin 622, 0.45 parts by weight of antioxidant 1010, 0.17 parts by weight of antioxidant 168 and 0.15 parts by weight of zinc stearate were mixed and then melted, extruded, cooled and pelletized in a twin-screw extruder with the following temperatures from the feeding section to the die head section: 80℃, 165℃, 185℃, 195℃, 200℃, 205℃, 200℃, 195℃, 190℃, 190℃, and screw speed of 270 rpm. (3) Preparation of cable material: The cable material particles are extruded through a die in an extruder and coated on the outside of the conductor. After cooling, shaping and winding, the cable material is obtained.

[0039] Example 3 (1) Preparation of masterbatch: 72 parts by weight of polypropylene, 5.6 parts by weight of PP-g-MAH, 16.5 parts by weight of the composite hybrid material prepared in Example 1, 0.9 parts by weight of antioxidant 1010, 0.5 parts by weight of antioxidant 168 and 0.8 parts by weight of zinc stearate were mixed evenly and then melted, extruded, cooled and pelletized in a twin-screw extruder with the following temperatures from the feeding section to the die head section: 80℃, 155℃, 175℃, 195℃, 200℃, 205℃, 200℃, 200℃, 195℃ and 195℃ respectively, and the screw speed was 240 rpm. (2) Preparation of cable material particles: 71 parts by weight of polypropylene, 18 parts by weight of the masterbatch obtained in step (1), 5.2 parts by weight of PP-g-MAH, 0.27 parts by weight of Tinuvin 622, 0.35 parts by weight of antioxidant 1010, 0.16 parts by weight of antioxidant 168 and 0.12 parts by weight of zinc stearate were mixed and then melted, extruded, cooled and pelletized in a twin-screw extruder with the following temperatures from the feeding section to the die head section: 80℃, 165℃, 185℃, 200℃, 200℃, 205℃, 200℃, 200℃, 195℃, 195℃, and screw speed of 280 rpm. (3) Preparation of cable material: The cable material particles are extruded through a die in an extruder and coated on the outside of the conductor. After cooling, shaping and winding, the cable material is obtained.

[0040] Example 4 (1) Preparation of masterbatch: 70.5 parts by weight of polypropylene, 5.8 parts by weight of PP-g-MAH, 17 parts by weight of the composite hybrid material prepared in Example 3, 0.8 parts by weight of antioxidant 1010, 0.5 parts by weight of antioxidant 168 and 0.7 parts by weight of zinc stearate were mixed evenly and then melted, extruded, cooled and pelletized in a twin-screw extruder with the following temperatures from the feeding section to the die head section: 75℃, 150℃, 170℃, 195℃, 200℃, 205℃, 205℃, 200℃, 195℃ and 195℃ respectively, and the screw speed was 230 rpm. (2) Preparation of cable material particles: 75 parts by weight of polypropylene, 17 parts by weight of the masterbatch obtained in step (1), 5.1 parts by weight of PP-g-MAH, 0.26 parts by weight of Tinuvin 622, 0.5 parts by weight of antioxidant 1010, 0.2 parts by weight of antioxidant 168 and 0.15 parts by weight of zinc stearate are mixed and then melted, extruded, cooled and pelletized in a twin-screw extruder with the following temperatures from the feeding section to the die head section: 80℃, 170℃, 185℃, 195℃, 205℃, 205℃, 195℃, 195℃, 195℃, and screw speed of 270 rpm. (3) Preparation of cable material: The cable material particles are extruded through a die in an extruder and coated on the outside of the conductor. After cooling, shaping and winding, the cable material is obtained.

[0041] Example 5 (1) Preparation of masterbatch: 71 parts by weight of polypropylene, 6 parts by weight of PP-g-MAH, 18 parts by weight of the composite hybrid material prepared in Example 4, 0.9 parts by weight of antioxidant 1010, 0.6 parts by weight of antioxidant 168, and 1 part by weight of zinc stearate were mixed evenly and then melted, extruded, cooled, and pelletized in a twin-screw extruder with the following temperatures from the feeding section to the die head section: 80℃, 160℃, 180℃, 190℃, 195℃, 205℃, 205℃, 200℃, 195℃, and 195℃, and the screw speed was 250 rpm. (2) Preparation of cable material particles: 72 parts by weight of polypropylene, 20 parts by weight of the masterbatch obtained in step (1), 5.5 parts by weight of PP-g-MAH, 0.28 parts by weight of Tinuvin 622, 0.4 parts by weight of antioxidant 1010, 0.18 parts by weight of antioxidant 168 and 0.15 parts by weight of zinc stearate are mixed and then melted, extruded, cooled and pelletized in a twin-screw extruder with the following temperatures from the feeding section to the die head section: 75℃, 170℃, 190℃, 195℃, 205℃, 205℃, 200℃, 195℃, 195℃, and screw speed of 270 rpm. (3) Preparation of cable material: The cable material particles are extruded through a die in an extruder and coated on the outside of the conductor. After cooling, shaping and winding, the cable material is obtained.

[0042] Comparative Example 1 Compared with Example 1, the difference is that a composite hybrid without silver nitrate solution was used instead of the composite hybrid prepared in Example 5 of Example 1, while all other aspects remained the same.

[0043] Comparative Example 2 Compared with Example 1, the difference is that a composite hybrid without modified carbon nanotubes was used instead of the composite hybrid prepared in Example 5 of Example 1, while all other aspects remained the same.

[0044] Comparative Example 3 Compared with Example 1, the difference is that a composite hybrid without added dopamine hydrochloride was used instead of the composite hybrid prepared in Example 5 of Example 1, while all other aspects remained the same.

[0045] Comparative Example 4 Compared with Example 1, the difference is that a composite hybrid without the addition of 4,4'-diglycidoxybiphenyl was used instead of the composite hybrid prepared in Example 5 of Example 1, while all other aspects remained the same.

[0046] Comparative Example 5 Compared with Example 1, the difference is that a composite hybrid without the addition of 4-amino-2,2,6,6-tetramethylpiperidine was used instead of the composite hybrid prepared in Example 5 of Example 1, while all other aspects remained the same.

[0047] Comparative Example 6 Compared with Example 1, the difference is that a composite hybrid without the addition of silane coupling agent KH-560 is used instead of the composite hybrid prepared in Example 5 of Example 1, while all other aspects remain the same.

[0048] Comparative Example 7 Compared with Example 1, the difference is that a composite hybrid without the addition of nitric oxide free radical piperidinol is used instead of the composite hybrid prepared in Example 5 of Example 1, while all other aspects remain unchanged.

[0049] Comparative Example 8 Compared with Example 1, the difference is that Tinuvin 622 is not added, while everything else remains the same.

[0050] Test Example 1 According to GB / T 10297-2015 and GB / T 2951.12-2008, the thermal conductivity and thermal conductivity after aging of the cable material particles prepared in Examples 1-5, Comparative Examples 1-3 and Comparative Examples 1-8 were tested, and the results are shown in Table 1.

[0051] Table 1

[0052] As can be clearly seen from the data comparison in Table 1, the thermal conductivity of the cable material particles prepared in Examples 1-5 of the present invention is significantly higher than that of the cable material particles in Comparative Examples 1-3 and 7-8. This indicates that the cable material prepared by the process of the present invention has outstanding thermal conductivity and superior heat conduction capability. The changes in thermal conductivity before aging and after aging at 158°C for 168 hours also clearly show that the nitrile free radical piperidine alcohol and Tinuvin 622 added in the present invention can provide anti-aging protection to maintain long-term thermal conductivity stability.

[0053] Test Example 2 According to GB / T 1410-2006, the volume resistivity and aging volume resistivity of the cable material particles prepared in Examples 1-5 and Comparative Examples 3-8 were tested, and the results are shown in Table 2.

[0054] Table 2

[0055] As can be clearly seen from the volume resistivity test data in Table 2, the volume resistivity values ​​of the cable material particles prepared in Examples 1-5 of this invention are significantly higher than those of Comparative Examples 3-5. This indicates that the dopamine hydrochloride, 4,4'-diglycidoxybiphenyl, and 4-amino-2,2,6,6-tetramethylpiperidine added in this invention all significantly help to improve the insulation performance of the cable. As can be seen from Comparative Example 6, the composite hybrid material without the addition of silane coupling agent KH-560 may have a small number of conductive channels, and its volume resistivity value is poor. This indicates that the silane coupling agent KH-560 added in this invention can further isolate and modify magnesium oxide, reduce the formation of its conductive channels, and achieve a synergistic improvement in insulation and thermal conductivity. It is also easy to see from the changes in volume resistivity of Comparative Examples 7-8 before aging and after aging at 158°C for 168 hours that the nitroxide free radical piperidinol and Tinuvin 622 added in this invention can effectively maintain the long-term high insulation requirements of the prepared cable material.

[0056] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the present invention.

Claims

1. A high-performance polypropylene cable material, characterized in that, Including the following parts by weight of raw materials: Polypropylene 70-75 parts by weight, masterbatch 16-20 parts by weight, PP-g-MAH 5-5.5 parts by weight, Tinuvin 622 0.25-0.3 parts by weight, antioxidant 1010 0.3-0.5 parts by weight, antioxidant 168 0.15-0.2 parts by weight, zinc stearate 0.1-0.15 parts by weight; The masterbatch comprises the following raw materials in parts by weight: 70-72 parts by weight of polypropylene, 5.5-6 parts by weight of PP-g-MAH, 15-18 parts by weight of composite hybrid, 0.8-1 parts by weight of antioxidant 1010, 0.4-0.6 parts by weight of antioxidant 168, and 0.6-1 parts by weight of zinc stearate; The composite hybrid material is prepared by stirring with dopamine hydrochloride in the dark, and then modifying it with 4,4'-diglycidoxybiphenyl, 4-amino-2,2,6,6-tetramethylpiperidine and nitroxide free radical piperinol.

2. The high-performance polypropylene cable material according to claim 1, characterized in that, The specific preparation method of the modified magnesium oxide includes the following steps: Magnesium oxide and anhydrous ethanol were mixed and ultrasonically dispersed, then centrifuged and dried to obtain pretreated magnesium oxide. Pretreated magnesium oxide and N,N-dimethylformamide were mixed and ultrasonically dispersed, polyvinylpyrrolidone was added and stirred, silver nitrate solution was added dropwise under nitrogen atmosphere, the temperature was raised and the stirring speed was controlled, cooled, centrifuged, washed and dried to obtain dry intermediate material; The dried intermediate material was added to an ethanol solution, the pH was adjusted, and silane coupling agent KH-560 was added dropwise under reflux and stirring. After centrifugation, washing, and drying, modified magnesium oxide was obtained.

3. The high-performance polypropylene cable material according to claim 2, characterized in that, In the preparation of pretreated magnesium oxide: the ratio of magnesium oxide to anhydrous ethanol is 8.5-10g:100-120mL; In the preparation of the dried intermediate material: the ratio of the pretreated magnesium oxide, N,N-dimethylformamide, polyvinylpyrrolidone, and silver nitrate solution is 9-10g:500-540mL:2-2.4g:0.34-0.4g; In the preparation of modified magnesium oxide: the ratio of the dry intermediate material, ethanol solution and silane coupling agent KH-560 is 9-10g:400-420mL:0.3-0.5g.

4. The high-performance polypropylene cable material according to claim 1, characterized in that, The specific preparation method of the modified carbon nanotubes includes the following steps: The mixture and multi-walled carbon nanotubes were mixed and sonicated, centrifuged, washed and dried to obtain acidified carbon nanotubes. The acidified carbon nanotubes were mixed with an ethanol solution, the pH was adjusted, the mixture was ultrasonically dispersed, and silane coupling agent KH-550 was added dropwise under reflux and stirring. The mixture was then centrifuged, washed, and dried to obtain modified carbon nanotubes.

5. The high-performance polypropylene cable material according to claim 4, characterized in that, In the preparation of acidified carbon nanotubes: the ratio of the mixture to multi-walled carbon nanotubes is 250-270 mL: 4.5-5 g; In the preparation of modified carbon nanotubes: the ratio of the acidified carbon nanotubes, ethanol solution and silane coupling agent KH-550 is 5-5.5g:300-350mL:0.25-0.3g.

6. The high-performance polypropylene cable material according to claim 1, characterized in that, The specific preparation method of the composite hybrid material includes the following steps: Tris-HCl buffer, modified magnesium oxide and modified carbon nanotubes were mixed and ultrasonically dispersed, dopamine hydrochloride was added and stirred in the dark, centrifuged, washed and dried to obtain intermediate modified material; N,N-dimethylformamide was preheated, and 4,4'-diglycidyloxybiphenyl and intermediate modified material were added and ultrasonically dispersed. Triethylamine was then added and stirred under controlled temperature. After cooling, 4-amino-2,2,6,6-tetramethylpiperidine was added dropwise and stirred in the dark for the first time. Nitrogen oxide free radical piperidinol was added and stirred in the dark for the second time. After cooling, centrifugation, washing, and drying, the composite hybrid material was obtained.

7. The high-performance polypropylene cable material according to claim 6, characterized in that, In the preparation of the intermediate modified material: the ratio of Tris-HCl buffer, modified magnesium oxide, modified carbon nanotubes and dopamine hydrochloride is 500-520mL:9.5-10g:0.7-1g:0.7-1.0g; In the preparation of the composite hybrid material: the ratio of N,N-dimethylformamide, 4,4'-diglycidoxybiphenyl, intermediate modifier, triethylamine, 4-amino-2,2,6,6-tetramethylpiperidine and nitroxide free radical piperidinol is 200-230mL:1.8-2g:10-10.7g:0.2-0.25mL:0.5-0.6g:0.15-0.18g.

8. The high-performance polypropylene cable material according to claim 6, characterized in that, In the preparation process of intermediate modified materials: The ultrasonic dispersion is performed at a power of 180-200W for 60-70 minutes; the light-protected stirring is performed at a speed of 280-300 rpm for 12-15 hours; the centrifugation is performed at a speed of 7000-8000 rpm for 10-15 minutes; and the drying is performed under vacuum at 55-60°C for 20-24 hours. In the preparation process of composite hybrid materials: The preheating temperature is 55-60℃; the ultrasonic dispersion time is 20-30 min; the temperature for temperature-controlled stirring is 75-80℃ and the time is 3-3.5 h; the cooling temperature is reduced to 60-70℃; the temperature for the first light-protected stirring is 60-65℃ and the time is 3-3.5 h; the heating temperature is 68-72℃; the time for the second light-protected stirring is 2-2.5 h; the washing process involves washing 2-3 times each with N,N-dimethylformamide and anhydrous ethanol, then washing with deionized water until neutral, and finally washing 2-3 times with anhydrous ethanol; the drying process involves vacuum drying at a controlled temperature of 55-60℃ for 8-10 h.

9. A method for preparing a high-performance polypropylene cable material as described in any one of claims 1-8, characterized in that, Includes the following steps: (1) Preparation of masterbatch: Polypropylene, PP-g-MAH, composite hybrid material, antioxidant 1010, antioxidant 168 and zinc stearate are mixed evenly, and then melt-extruded, cooled and pelletized by twin-screw extruder to obtain masterbatch; (2) Preparation of cable material particles: Polypropylene, the masterbatch obtained in step (1), PP-g-MAH, Tinuvin 622, antioxidant 1010, antioxidant 168 and zinc stearate are mixed evenly, and then melt-extruded, cooled and pelletized by twin-screw extruder to obtain cable material particles. (3) Preparation of cable material: The cable material particles are extruded through a die in an extruder and coated on the outside of the conductor. After cooling, shaping and winding, the cable material is obtained.

10. The method for preparing high-performance polypropylene cable material according to claim 9, characterized in that, The temperatures of each section of the twin-screw extruder from the feeding section to the die head section in step (1) are as follows: 75-80℃, 150-160℃, 170-180℃, 190-195℃, 195-200℃, 200-205℃, 200-205℃, 195-200℃, 190-195℃, 190-195℃; the screw speed of the twin-screw extruder is 230-250 rpm. The temperatures of each section of the twin-screw extruder from the feeding section to the die head section in step (2) are as follows: 75-80℃, 165-170℃, 180-190℃, 190-200℃, 200-205℃, 200-205℃, 200-205℃, 195-200℃, 190-195℃, 190-195℃; the screw speed of the twin-screw extruder is 260-280 rpm. The conductor mentioned in step (3) includes, but is not limited to, copper core wire or aluminum core wire.

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