High-temperature-resistant power cable

Abstract

The invention relates to the technical field of cables, and provides a high-temperature-resistant power cable. The high-temperature-resistant power cable comprises a conductor and a high-temperature-resistant outer sheath, the high-temperature-resistant outer sheath is prepared from the following raw materials in parts by weight: 80 to 90 parts of linear low-density polyethylene, 10 to 15 parts of ethylene-vinyl acetate copolymer, 20 to 25 parts of polyurethane grafted aluminum borate whisker, 12 to 15 parts of polyolefin elastomer, 0.5 to 1 part of antioxidant, 0.8 to 1 part of dicumyl peroxide, 1.0 to 1.2 parts of crosslinking aid TAIC, 0.3 to 0.8 part of stabilizer, 0.5 to 1 part of calcium stearate and 0.2 to 0.5 part of polyethylene wax. According to the cable prepared in the invention, the stability of the interlayer structure of the high-temperature-resistant power cable during long-term high-temperature operation is improved, and the anti-degradation performance of the material of the high-temperature-resistant power cable in a long-term high-temperature environment is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cables, in particular, relates to a kind of high temperature resistant power cable. BACKGROUND

[0002] The existing high temperature resistant power cable is widely used in many high temperature industrial fields due to its specific performance advantages.In the metallurgical industry, it is used for power transmission of high temperature equipment such as blast furnace, converter and electric furnace, to ensure the normal operation of the equipment in high temperature environment. In the chemical industry, it provides power support for high temperature reaction kettle, distillation column and other equipment, while resisting the corrosion of chemical medium. In the field of aerospace, high temperature resistant cable is used for electrical connection of high temperature parts such as aircraft engine and rocket, to meet the use requirements in extreme environment. In addition, it also has important application in the field of nuclear power plant and high temperature geothermal power generation in power industry.

[0003] During long-term high temperature operation, the existing high temperature resistant power cable is prone to performance instability. On the one hand, due to the difference in thermal expansion coefficient of materials, stress may occur between the insulation layer and the conductor, and between the insulation layer and the sheath layer when the temperature changes, which may cause interlayer peeling, cracking and other problems, affecting the overall performance of the cable. On the other hand, high temperature can accelerate the chemical reaction and physical change inside the material, such as oxidation and decomposition, which may gradually deteriorate the performance of the material and reduce the reliability and service life of the cable. In order to solve the above technical problems, the present application proposes a new high temperature resistant power cable. SUMMARY

[0004] The present application proposes a kind of high temperature resistant power cable, which improves the stability of interlayer structure of high temperature resistant power cable under long-term high temperature operation, and improves the anti-deterioration performance of material of high temperature resistant power cable in long-term high temperature environment.

[0005] The technical scheme of the present application is as follows: In a first aspect, the present application proposes a kind of high temperature resistant power cable, which includes conductor and high temperature resistant outer sheath, the high temperature resistant outer sheath is composed of the following weight parts of raw materials: linear low density polyethylene 80-90 parts, ethylene-vinyl acetate copolymer 10-15 parts, polyurethane grafted aluminum borate whisker 20-25 parts, polyolefin elastomer 12-15 parts, antioxidant 0.5-1 part, dicumyl peroxide 0.8-1 part, crosslinking aid TAIC 1.0-1.2 parts, stabilizer 0.3-0.8 parts, calcium stearate 0.5-1 parts, polyethylene wax 0.2-0.5 parts.

[0006] The application utilizes a "peroxide-triazine ring" synergistic crosslinking system, in which dicumyl peroxide (DCP) is used as the main crosslinking agent to generate free radicals at high temperature, initiating carbon-carbon crosslinking of polyethylene chains; the triazine ring structure of the crosslinking co-agent TAIC has a unique electronic effect, which can stabilize the free radicals generated by DCP decomposition and participate in the formation of more stable C-N crosslinking bonds. This dual crosslinking agent system not only improves the crosslinking density, but also optimizes the uniformity of the crosslinking network. During the thermal aging process, the traditional single crosslinking system is prone to stress concentration due to excessive local crosslinking density, accelerating the polymer chain rupture; while the synergistic crosslinking system of the application absorbs ultraviolet light and thermal energy through the aromatic structure of the triazine ring, inhibits the free radical chain reaction, and at the same time its rigid structure restricts the movement of polymer chain segments, slowing down the rate of oxidative degradation. The complementary effect of "physical crosslinking-chemical crosslinking" makes the material still maintain excellent mechanical properties and electrical properties at high temperature for a long time.

[0007] As a further technical solution, the preparation method of the polyurethane grafted aluminum borate whisker comprises: after vacuum dehydration pretreatment of polyether glycol, mixing with toluene diisocyanate and dibutyltin dilaurate at 75±5 DEG C, and after 2-3 hours of reaction, polyurethane prepolymer is obtained; then the polyurethane prepolymer is added into a N,N-dimethylformamide solution containing silanized aluminum borate whisker, and the reaction is carried out at a temperature of 85±2 DEG C, 250-350 rpm, under nitrogen protection for 4-5 hours, the moisture content of the reaction system is controlled to be less than or equal to 0.05%, methanol is added to terminate the reaction, centrifugal separation is carried out, and the precipitate is obtained, which is washed and dried to obtain the polyurethane grafted aluminum borate whisker.

[0008] The application adopts a "calcination activation-silane coupling-polyurethane grafting" three-stage surface treatment process to construct a multi-scale interface strengthening system. First, high-temperature calcination removes the adsorbed water and organic impurities on the surface of the whisker, and increases the density of the surface hydroxyl group, providing active sites for subsequent silanization; second, the silane coupling agent KH-550 forms an organic monolayer on the surface of the whisker through hydrolysis and condensation reaction, reducing the surface polarity; finally, the polyurethane prepolymer reacts with the amino / hydroxyl groups on the surface of the silanized whisker to form a chemically bonded polyurethane grafting layer. This hierarchical treatment process has a dual synergistic effect: on the one hand, the silanized layer acts as a "molecular bridge" to alleviate the modulus mismatch between inorganic whiskers and organic polymers; on the other hand, the polyurethane grafting layer enhances the physical interlocking with the matrix resin through chain entanglement. Experiments show that omitting any treatment step will significantly reduce the interface bonding strength, verifying the necessity of the three-stage treatment process.

[0009] As a further technical solution, the vacuum dehydration pretreatment step is: vacuum dehydration of polyether glycol at 100-110 DEG C, -0.095±0.005 MPa for 120-140 min.

[0010] As a further technical scheme, the configuration method of the N,N-dimethylformamide solution containing the silanized aluminum borate whisker is as follows: the silanized aluminum borate whisker is added into N,N-dimethylformamide, and after ultrasonic dispersion for 30-40 min under 450-550 W, the N,N-dimethylformamide solution containing the silanized aluminum borate whisker is obtained.

[0011] As a further technical scheme, the weight ratio of the silanized aluminum borate whisker and N,N-dimethylformamide is 2-3:10.

[0012] As a further technical scheme, the preparation method of the silanized aluminum borate whisker comprises the following steps: calcining aluminum borate whisker at a temperature of 450-550 ℃ for 2-3 h, then uniformly mixing the calcined whisker, silane coupling agent KH-550 and ethanol, refluxing and stirring at 75-85 ℃ for 3-4 h, and filtering, washing and drying to obtain the silanized aluminum borate whisker.

[0013] As a further technical scheme, the weight ratio of the calcined whisker and silane coupling agent KH-550 is 100:1-2.

[0014] As a further technical scheme, the weight ratio of the polyether glycol, toluene diisocyanate and dibutyl tin dilaurate is 10-15:15-20:0.1-0.3.

[0015] As a further technical scheme, the antioxidant comprises at least one of antioxidant 1010 and antioxidant 168; and the stabilizer comprises at least one of UV-531, UV-326 and hindered amine light stabilizer 770.

[0016] In the second aspect, the application provides a preparation method of a high-temperature-resistant power cable, which comprises the following steps: weighing raw materials according to a formula, mixing linear low-density polyethylene, ethylene-vinyl acetate copolymer and polyolefin elastomer, and melting for 4-6 min at 145-155 ℃, mixing calcium stearate and polyethylene wax for 2-4 min, mixing an antioxidant and a stabilizer for 1-2 min, adding polyurethane grafted aluminum borate whisker in 2-3 times, and mixing at 50-60 rpm and 155-165 ℃ for 8-10 min, finally mixing dicumyl peroxide and crosslinking aid TAIC at 100-110 ℃ for 3-5 min; and extruding the high-temperature-resistant power cable by a double-screw extruder, wherein the temperature of a first zone of the double-screw extruder is 125-135 ℃, the temperature of a second zone is 145-155 ℃, the temperature of a third zone is 155-165 ℃, and the temperature of a die head is 145-155 ℃.

[0017] The working principle and beneficial effects of the application are as follows: The present application grafts polyurethane segments chemically on the surface of aluminum borate whiskers, and constructs a "rigid whisker-flexible polymer" core-shell structure. This structure forms a synergistic effect between gas-phase flame retardation and condensed-phase flame retardation: when the material is decomposed by heat, the polyurethane segments decompose first to produce inert gas, diluting the concentration of combustible gas; at the same time, the aluminum borate whisker, as an inorganic nano filler, promotes the formation of a dense carbon layer, effectively blocking the transmission of heat and oxygen. The synergistic effect of the two significantly improves the limiting oxygen index of the material, breaking through the limitations of traditional inorganic fillers which simply physically block. In terms of mechanical reinforcement, the polyurethane grafting layer significantly improves the interfacial compatibility of the whisker and the polymer matrix through the dual action of chemical bonding and physical entanglement. Traditional unmodified whiskers easily agglomerate due to differences in surface energy, forming stress concentration points; while the grafted whiskers can be uniformly dispersed in the matrix, realizing the synchronous improvement of tensile strength and fracture toughness through the rigidity of the whisker and the flexibility of the polyurethane. This "hard-soft" gradient transition structure effectively solves the brittleness problem caused by inorganic filler reinforcement. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor also fall within the scope of protection of the present application.

[0019] It should be noted that in the present application, the linear low density polyethylene is model DFDA-8320; the ethylene-vinyl acetate copolymer is model WV1055; the polyolefin elastomer is purchased from Tuoshou (Suzhou) New Material Co., Ltd., and the brand is 8411; the polyethylene wax is purchased from Qingdao Haijiao Chemical Co., Ltd., and the model is H100.

[0020] Embodiment 1 The present embodiment provides a high-temperature-resistant power cable, which comprises a conductor and a high-temperature-resistant outer sheath, and the high-temperature-resistant outer sheath is composed of the following raw materials in parts by weight: linear low density polyethylene 85 parts, ethylene-vinyl acetate copolymer 12 parts, polyurethane grafted aluminum borate whisker 22 parts, polyolefin elastomer 13 parts, antioxidant 1010 0.8 parts, dicumyl peroxide 0.9 parts, crosslinking aid TAIC 1.1 parts, stabilizer UV-531 0.5 parts, calcium stearate 0.8 parts, and polyethylene wax 0.3 parts. The preparation method of the polyurethane grafted aluminum borate whisker comprises the following steps: 12 parts of polyether diol are pretreated by dehydration at 105℃ under a vacuum of-0.095MPa for 130min, mixed with 18 parts of toluene diisocyanate and 0.2 parts of dibutyltin dilaurate at 75℃, and reacted for 2.5h to obtain a polyurethane prepolymer; The aluminum borate whisker is calcined at 500℃ for 2.5h, then 100 parts of the calcined whisker, 1.5 parts of silane coupling agent KH-550 and 120 parts of ethanol are uniformly mixed, refluxed and stirred at 80℃ for 3.5h, filtered, washed with ethanol for 3 times, and vacuum dried at 110℃ for 6h to obtain the silanized aluminum borate whisker; The prepared silanized aluminum borate whisker is added into N,N-dimethylformamide, and an N,N-dimethylformamide solution containing the silanized aluminum borate whisker is obtained by ultrasonic dispersion at 500W for 35min; the weight ratio of the silanized aluminum borate whisker to N,N-dimethylformamide is 2.5:10; Then, the above polyurethane prepolymer is added into the above N,N-dimethylformamide solution containing the silanized aluminum borate whisker, and reacted at 85℃ under nitrogen protection at 300rpm for 4.5h, with the moisture content of the reaction system controlled at 0.05%, and the reaction is terminated by adding methanol; after centrifugal separation, washing and drying, the polyurethane grafted aluminum borate whisker is obtained; The preparation method of the high-temperature-resistant power cable comprises the following steps: weighing raw materials according to a formula, mixing linear low-density polyethylene, ethylene-vinyl acetate copolymer and polyolefin elastomer, melting at 150℃ for 5min, mixing calcium stearate and polyethylene wax for 3min, mixing antioxidant 1010 and stabilizer UV-531 for 1.5min, adding polyurethane grafted aluminum borate whisker in two times, mixing at 55rpm and 160℃ for 9min, and finally mixing benzoyl peroxide and crosslinking aid TAIC at 105℃ for 4min; the high-temperature-resistant power cable is formed by extruding the conductor through a double-screw extruder, wherein the temperature of the first zone of the double-screw extruder is 130℃, the temperature of the second zone is 150℃, the temperature of the third zone is 160℃, and the temperature of the die head is 150℃.

[0021] Example 2 The present embodiment provides a high-temperature-resistant power cable, which comprises a conductor and a high-temperature-resistant outer sheath, and the high-temperature-resistant outer sheath is composed of the following raw materials by weight: linear low-density polyethylene 80 parts, ethylene-vinyl acetate copolymer 10 parts, polyurethane grafted aluminum borate whisker 20 parts, polyolefin elastomer 12 parts, antioxidant 1010 0.5 parts, benzoyl peroxide 0.8 parts, crosslinking aid TAIC 1.0 parts, stabilizer UV-531 0.3 parts, calcium stearate 0.5 parts, and polyethylene wax 0.2 parts. The preparation method of the polyurethane grafted aluminum borate whisker comprises the following steps: 10 parts of polyether diol is pretreated by dehydration at 100℃ under a vacuum of-0.095MPa for 120min, mixed with 15 parts of toluene diisocyanate and 0.1 part of dibutyltin dilaurate at 75℃, and reacted for 2h to obtain a polyurethane prepolymer; The aluminum borate whisker is calcined at 450℃ for 2h, then 100 parts of the calcined whisker, 1 part of silane coupling agent KH-550 and 120 parts of ethanol are uniformly mixed, refluxed and stirred at 75℃ for 3h, filtered, washed with ethanol for 3 times, and vacuum dried at 110℃ for 6h to obtain the silanized aluminum borate whisker; The prepared silanized aluminum borate whisker is added into N,N-dimethylformamide, and an N,N-dimethylformamide solution containing the silanized aluminum borate whisker is obtained by ultrasonic dispersion at 450W for 30min; the weight ratio of the silanized aluminum borate whisker to N,N-dimethylformamide is 2:10; Then, the polyurethane prepolymer is added into the aforementioned N,N-dimethylformamide solution containing the silanized aluminum borate whisker, and reacted at 85℃ under nitrogen protection at 250rpm for 4h, while the moisture content of the reaction system is controlled at 0.05%, and the reaction is terminated by adding methanol; after centrifugal separation, washing and drying, the polyurethane grafted aluminum borate whisker is obtained; The preparation method of the high-temperature-resistant power cable includes the following steps: weighing the raw materials according to the formula, mixing the linear low-density polyethylene, ethylene-vinyl acetate copolymer and polyolefin elastomer, melting at 145℃ for 4min, mixing the calcium stearate and polyethylene wax for 2min, mixing the antioxidant 1010 and stabilizer UV-531 for 1min, mixing the polyurethane grafted aluminum borate whisker in two times at 50rpm and 155℃ for 8min, and finally mixing the dicumyl peroxide and crosslinking aid TAIC at 100℃ for 3min; the high-temperature-resistant power cable is formed by extruding the conductor through a double-screw extruder, wherein the temperature of the first zone is 125℃, the temperature of the second zone is 145℃, the temperature of the third zone is 155℃, and the temperature of the die head is 145℃.

[0022] Example 3 The present embodiment provides a high-temperature-resistant power cable, which includes a conductor and a high-temperature-resistant outer sheath, and the high-temperature-resistant outer sheath is composed of the following raw materials by weight: linear low-density polyethylene 90 parts, ethylene-vinyl acetate copolymer 15 parts, polyurethane grafted aluminum borate whisker 25 parts, polyolefin elastomer 15 parts, antioxidant 1010 1 part, dicumyl peroxide 1 part, crosslinking aid TAIC 1.2 parts, stabilizer UV-531 0.8 parts, calcium stearate 1 part, and polyethylene wax 0.5 part. The preparation method of the polyurethane grafted aluminum borate whisker includes the following steps: The polyurethane prepolymer is obtained by mixing 15 parts of polyether diol, 20 parts of toluene diisocyanate and 0.3 parts of dibutyltin dilaurate at 75℃ for 3h after dehydration at 110℃ and -0.095MPa vacuum for 140min; The aluminum borate whisker is calcined at 550℃ for 3h, then 100 parts of the calcined whisker, 2 parts of silane coupling agent KH-550 and 120 parts of ethanol are uniformly mixed, refluxed and stirred at 85℃ for 4h, filtered, washed with ethanol for 3 times, and vacuum dried at 110℃ for 6h to obtain the silanized aluminum borate whisker; The prepared silanized aluminum borate whisker is added into N,N-dimethylformamide, and an N,N-dimethylformamide solution containing the silanized aluminum borate whisker is obtained by ultrasonic dispersion at 550W for 40min; the weight ratio of the silanized aluminum borate whisker to N,N-dimethylformamide is 3:10; Then, the polyurethane prepolymer is added into the aforementioned N,N-dimethylformamide solution containing the silanized aluminum borate whisker, and reacted at 85℃ under nitrogen protection at 350rpm for 5h, with the moisture content of the reaction system being controlled at 0.05%, and the reaction is terminated by adding methanol; after centrifugal separation, washing and drying, the polyurethane grafted aluminum borate whisker is obtained; The preparation method of the high-temperature-resistant power cable includes the following steps: weighing raw materials according to the formula, mixing linear low-density polyethylene, ethylene-vinyl acetate copolymer and polyolefin elastomer, melting at 155℃ for 6min, mixing calcium stearate and polyethylene wax for 4min, mixing antioxidant 1010 and stabilizer UV-531 for 2min, mixing the polyurethane grafted aluminum borate whisker in three times at 60rpm and 165℃ for 10min, and finally mixing dicumyl peroxide and crosslinking aid TAIC at 110℃ for 5min; the high-temperature-resistant power cable is formed by extruding the conductor through a double-screw extruder, wherein the temperature of the first zone is 135℃, the temperature of the second zone is 155℃, the temperature of the third zone is 165℃, and the temperature of the die head is 155℃.

[0023] Example 4 In the preparation of the polyurethane grafted aluminum borate whisker in this example, the aluminum borate whisker is not silanized, and the preparation method includes: adding the prepared polyurethane prepolymer into the aforementioned N,N-dimethylformamide solution containing the aluminum borate whisker, and reacting at 85℃ under nitrogen protection at 300rpm for 4.5h, with the moisture content of the reaction system being controlled at 0.05%, and the reaction is terminated by adding methanol; after centrifugal separation, washing and drying, the polyurethane grafted aluminum borate whisker is obtained, and the rest is the same as in Example 1.

[0024] Example 5 In this example, the aluminum borate whisker is calcined at 500℃, and the rest is the same as in Example 1.

[0025] Comparative Example 1 In this comparative example, the polyurethane grafted aluminum borate whisker is completely removed, and the rest is the same as in Example 1.

[0026] Comparative Example 2 In the present comparative example, the polyurethane grafted aluminum borate whisker is replaced by equal amount of aluminum borate whisker, and the rest is the same as example 1.

[0027] Comparative Example 3 In the present comparative example, the polyurethane grafted aluminum borate whisker is replaced by equal amount of silanized aluminum borate whisker, and the rest is the same as example 1.

[0028] Comparative Example 4 In the present comparative example, the amount of polyurethane grafted aluminum borate whisker is reduced to 11 parts, and the rest is the same as example 1.

[0029] Comparative Example 5 In the present comparative example, the crosslinking coagent TAIC is replaced by trimethylolpropane triacrylate, and the rest is the same as example 1.

[0030] Test Example 1: The high temperature resistant power cable prepared in the foregoing examples 1-5 and comparative examples 1-5 is subjected to the following tests: Limiting Oxygen Index (LOI) test: The test is carried out in accordance with GB / T 2406.1-2008 “Plastics-Determination of the flammability of plastics-Part 1: Ignition time (vertical method) ”; Tensile strength: The test is carried out in accordance with GB / T 1040.1-2018 “Plastics-Determination of the tensile properties-Part 1: General test methods ”; Heat aging resistance: The test is carried out in accordance with GB / T 2951.12-2008 “Cables and optical fibers-Determination of the flammability of plastics-Part 1: Ignition time (vertical method) ”; the sample is placed in an oven at 200℃ for aging for 168 hours, the tensile strength after aging is tested, and the heat aging tensile strength retention rate is calculated; Hygrothermal aging resistance: After aging in a constant temperature and humidity chamber at 85℃ / 85%RH for 30 days, the tensile strength after aging is tested, and the hygrothermal aging tensile strength retention rate is calculated; Thermal cycle delamination: the cable sample is subjected to-40℃ for 2h, then raised to 85℃ for 2h, and the cycle is repeated for 20 times, and the cross section is observed; The test results are shown in Table 1 below: Table 1

[0031] In combination with the above, the flame retardancy improvement in examples 1-3 of the present application proves that the polyurethane grafted aluminum borate whisker achieves synergistic effect through dual mechanisms: aluminum borate decomposes and absorbs heat, reducing the combustion temperature; polyurethane forms carbon to cover the surface and isolate oxygen. The mechanical property strengthening is attributed to the rigid enhancement of the whisker; the polyurethane flexible chain improves the interface stress transfer and inhibits stress concentration. The grafting structure shields water and oxygen erosion, inhibits polymer chain scission, and achieves aging resistance optimization, and the whisker grafting is chemically bonded with the matrix, resisting cold and heat stress and achieving thermal cycle stability.

[0032] In addition, the performance of Comparative Example 2 was significantly lower than that of Example 1 due to weak agglomeration and interfacial bonding, and the tensile strength decreased by 21%. The performance of Comparative Example 3 was better than that of Comparative Example 2 but lower than that of Examples 1-3, proving that the grafted polyurethane can further improve the dispersibility and interfacial strength. The performance of Example 4 was lower than that of Examples 1-3, indicating that silanization is a prerequisite for ensuring grafting rate. The performance of Comparative Example 4 decreased overall after the amount of whiskers was reduced to 11 parts, verifying that 20-25 parts is the optimal range. The performance of Example 5 decreased due to the residual hydroxyl groups on the surface of the whiskers after calcination at 300°C, reducing the efficiency of the coupling agent. Although Comparative Example 5 had no delamination and acceptable performance, its aging resistance was slightly lower than that of the examples, indicating that the triazine ring structure of TAIC is more suitable for this system.

[0033] Only Examples 1-3 and Comparative Example 5 had no delamination, proving that whisker grafting or a strong crosslinking system can resist interfacial peeling caused by thermal stress. The present application builds a thermal cycle stable system from both material design and process control dimensions. At the material level, polyurethane grafted whiskers significantly enhance the interfacial adhesion of fillers and matrix through chemical bonding and mechanical interlocking; at the process level, a segmented temperature control extrusion process is used to ensure that the polymer melt undergoes a gradual process of "melting-plasticizing-crosslinking" during extrusion, avoiding structural defects caused by local overheating. Thermal cycle tests show that traditional materials are prone to microcracks at the whisker / matrix interface due to the mismatch of thermal expansion coefficients; the grafted structure of the present application buffers thermal stress through a flexible polyurethane layer, while the crosslinking network limits molecular chain slipping, effectively inhibiting crack propagation. In addition, the strong shearing action of the twin-screw extruder promotes the directional arrangement of the whiskers along the extrusion direction, forming an "oriented reinforcement" structure that further resists interfacial peeling caused by thermal stress.

[0034] The above is only a preferred embodiment of the present application and does not limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A high temperature resistant power cable, characterized in that, The high-temperature-resistant outer sheath is composed of the following raw materials in parts by weight: linear low-density polyethylene 80-90 parts, ethylene-vinyl acetate copolymer 10-15 parts, polyurethane grafted aluminum borate whisker 20-25 parts, polyolefin elastomer 12-15 parts, antioxidant 0.5-1 part, dicumyl peroxide 0.8-1 part, crosslinking aid TAIC 1.0-1.2 parts, stabilizer 0.3-0.8 parts, calcium stearate 0.5-1 part, and polyethylene wax 0.2-0.5 part.

2. A high temperature resistant power cable according to claim 1, characterized in that The preparation method of the polyurethane grafted aluminum borate whisker comprises the following steps: after vacuum dehydration pretreatment of polyether glycol, the polyether glycol is mixed with toluene diisocyanate and dibutyltin dilaurate at 75±5 DEG C, and a polyurethane prepolymer is obtained after reaction for 2-3 h; then the polyurethane prepolymer is added into a N,N-dimethylformamide solution containing silanized aluminum borate whisker, and reaction is carried out at a temperature of 85±2 DEG C, 250-350 rpm and under nitrogen protection for 4-5 h, with the moisture content of the reaction system being controlled to be less than or equal to 0.05%, methanol is added to terminate the reaction, centrifugal separation is carried out, and then the precipitate is washed and dried to obtain the polyurethane grafted aluminum borate whisker.

3. A high temperature resistant power cable according to claim 2, characterized in that The vacuum dehydration pretreatment step is vacuum dehydration of the polyether glycol at 100-110 DEG C and under a pressure of-0.095±0.005 MPa for 120-140 min.

4. A high temperature resistant power cable according to claim 2, characterized in that, The N,N-dimethylformamide solution containing silanized aluminum borate whisker is prepared by adding the silanized aluminum borate whisker into N,N-dimethylformamide and ultrasonic dispersion at 450-550 W for 30-40 min.

5. A high temperature resistant power cable according to claim 4, characterized in that The weight ratio of the silanized aluminum borate whisker to N,N-dimethylformamide is 2-3:

10.

6. A high temperature resistant power cable according to claim 5, characterized in that The preparation method of the silanized aluminum borate whisker comprises the following steps: calcination of aluminum borate whisker at a temperature of 450-550 DEG C for 2-3 h, then uniform mixing of the calcined whisker, silane coupling agent KH-550 and ethanol, reflux stirring at 75-85 DEG C for 3-4 h, and then filtration, washing and drying.

7. A high temperature resistant power cable according to claim 6, characterized in that The weight ratio of the calcined whisker to silane coupling agent KH-550 is 100:1-2.

8. A high temperature resistant power cable according to claim 2, characterized in that, The weight ratio of the polyether glycol, toluene diisocyanate and dibutyltin dilaurate is 10-15:15-20:0.1-0.

3.

9. A high temperature resistant power cable according to claim 1, characterized in that, The antioxidant comprises at least one of antioxidant 1010 and antioxidant 168; and the stabilizer comprises at least one of UV-531, UV-326 and hindered amine light stabilizer 770.

10. A process for the production of a high temperature resistant power cable according to any one of claims 1-9, characterized by the steps The high-temperature-resistant outer sheath is composed of the following raw materials in parts by weight: linear low-density polyethylene 80-90 parts, ethylene-vinyl acetate copolymer 10-15 parts, polyurethane grafted aluminum borate whisker 20-25 parts, polyolefin elastomer 12-15 parts, antioxidant 0.5-1 part, dicumyl peroxide 0.8-1 part, crosslinking aid TAIC 1.0-1.2 parts, stabilizer 0.3-0.8 parts, calcium stearate 0.5-1 part, and polyethylene wax 0.2-0.5 part. The raw materials are weighed according to the formula, the linear low-density polyethylene, ethylene-vinyl acetate copolymer and polyolefin elastomer are mixed and then melted at 145-155 DEG C for 4-6 min, the calcium stearate and polyethylene wax are mixed for 2-4 min, the antioxidants and stabilizers are mixed for 1-2 min, the polyurethane grafted aluminum borate whiskers are added in 2-3 times and mixed at 50-60 rpm and 155-165 DEG C for 8-10 min, finally the dicumyl peroxide and crosslinking aid TAIC are added and mixed at 100-110 DEG C for 3-5 min; the high-temperature-resistant power cable is formed by extruding the conductor outside layer through a double-screw extruder, the temperature of the first zone of the double-screw extruder is 125-135 DEG C, the temperature of the second zone is 145-155 DEG C, the temperature of the third zone is 155-165 DEG C, and the temperature of the die head is 145-155 DEG C.

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