Preparation method of high-temperature-resistant low-temperature-resistant high-toughness cable material and cable for oil platform

Abstract

The invention relates to the technical field of cables, in particular to a preparation method of a high-temperature-resistant low-temperature-resistant high-toughness cable material and a cable for an oil platform, the cable comprises a cable body, a bionic stranded conductor is arranged in the cable body, and a gradient insulating layer is fixedly connected to the surface of the bionic stranded conductor. The surface of the gradient insulation layer is fixedly connected with a three-layer co-extrusion sheath layer. According to the invention, the feasibility of a core innovation point (a bionic conductor and a gradient sheath) is proved through basic performance verification, the typical working conditions of an oil platform, such as low-temperature embrittlement and dynamic load, are covered through an extreme environment test, and the synergistic effect of key parameters (DCP dosage and vulcanization temperature) is determined through technological parameter optimization; the relation between quantitative repair efficiency and trigger conditions is verified through a self-repair mechanism, three-year equivalent aging is simulated through long-term reliability evaluation, the technical economy is proved, and meanwhile the core requirements of wide-temperature-range stability, mechanical fatigue resistance, chemical corrosion resistance and the like are met.

Description

Technical Field

[0001] The present invention relates to the technical field of cables, in particular to a method for preparing a high-temperature and low-temperature resistant high-toughness cable material and a cable for an oil platform. Background Art

[0002] The extremely complex environments of oil platforms and subsea oil and gas extraction expose cables to the following harsh conditions over long periods of time: Temperature fluctuations: alternating between Arctic and Middle Eastern waters can lead to thermal expansion and contraction failure of the material; chemical corrosion: salt spray, hydrogen sulfide, and crude oil erosion can cause sheath swelling and conductor oxidation; mechanical stress: platform vibration and drag loads can cause armor fractures or insulation damage; dynamic cross-linking limitations: traditional thermoset materials are highly brittle and cannot provide both toughness and toughness, and dynamically vulcanized materials are prone to delamination when co-extruded with thermoset sheath layers; Existing technologies find it difficult to simultaneously meet core requirements such as wide temperature range stability, mechanical fatigue resistance, and chemical corrosion resistance. Summary of the Invention

[0003] To this end, the present invention provides a method for preparing a high-temperature and low-temperature resistant high-toughness cable material and a cable for an oil platform to solve the above-mentioned problems.

[0004] The present invention provides the following technical solution: a cable for an oil platform, comprising a cable body, wherein a bionic twisted conductor is provided in the cable body, a gradient insulation layer is fixedly connected to the surface of the bionic twisted conductor, and a three-layer co-extruded sheath layer is fixedly connected to the surface of the gradient insulation layer; The sheath layer comprises a carbon nanotube layer, a graphene layer, and a self-healing polyurethane layer from the outside to the inside. The helical angle between the aramid fiber and the tinned copper wire in the bionic twisted conductor is 30° to 45°, and the twisting pitch between the aramid fiber and the tinned copper wire in the bionic twisted conductor is ≤12 times the conductor diameter. The self-repairing polyurethane layer contains caprolactone monomer microcapsules, the capsule particle size of the caprolactone monomer microcapsules is 50 to 200 μm, and the triggering temperature of the caprolactone monomer microcapsules is 60° C. to 80° C.

[0005] The method for preparing a high-temperature and low-temperature resistant high-toughness cable material adopts the above-mentioned oil platform cable, comprising the following steps: Step 1: Preparation of bionic twisted conductor; Step 2: co-extrusion of the gradient insulation layer; Step 3: Preparation of self-repairing polyurethane layer; Step 4: three-layer co-extrusion sheath molding; Step five: post-curing treatment.

[0006] As a preferred solution of the present invention, in step 1, more specifically: The material selection of bionic stranded conductors includes the following materials: Aramid fiber: The material's linear density is 1.67 dtex, the material's tensile strength is ≥3.6 GPa, and the material's elongation at break is 2.5%; Tinned copper wire: The material's purity is ≥99.99%, the material's diameter is 0.25-0.35 mm, the thickness of the tinned layer is 5-8 μm, and the tin purity is ≥99.3%; Lubricant: Calcium stearate is used, and the amount of lubricant added is 0.5%. The lubricant is used to reduce twisting friction; The stranding process of the bionic stranded conductor includes the following steps: Process 1: Select the CCV continuous vulcanizing unit and adjust the equipment parameters to ensure that the pulling speed is 25m / min, the stranding pitch is ≤12 times the conductor diameter, and the helix angle is 30° to 45°; Process 2: After the bionic twisted conductor is twisted, its surface is treated. After the conductor is twisted, it is treated with argon plasma to make the surface roughness of the bionic twisted conductor Ra ≤ 15nm. The surface of the bionic twisted conductor is then coated with a graphene anti-oxidation coating; Process three: After the surface treatment of the bionic stranded conductor, it is tested. According to the GB / T3956 standard, the single-wire DC resistance is guaranteed to be ≤0.0172Ω / km at a temperature of 20°C, and the tensile strength is guaranteed to be ≥450MPa after the ASTMD638 test.

[0007] As a preferred solution of the present invention, in step 2, more specifically: The material selection for the gradient insulation layer includes the following materials: Inner layer: DuPont TF30 is selected, the material thickness is 0.05~0.1mm, and the dielectric strength of the material is ≥17kV / mm; Outer layer: TPV dynamic vulcanization layer is selected, which contains SEBS substrate, POE-g-MAH, nano-silica and dicumyl peroxide. The ratio of SEBS substrate, POE-g-MAH, nano-silica and dicumyl peroxide is 45 parts: 12 parts: 4 parts: 0.8 parts; The production process of the gradient insulation layer includes the following steps: In process 1, a twin-screw extruder is selected as the main equipment, and the length-to-diameter ratio of the twin-screw extruder is 48:1; Process 2: Adjust the temperature gradient of the twin-screw extruder: in the inner PTFE layer, the temperature of zone I is 280°C, the temperature of the die head is 290°C; in the outer TPV layer, the temperature of zone II is 220°C, and the temperature of the die head is 230°C. Adjust the screw speed of the twin-screw extruder to 300 rpm, set the cooling mode of the twin-screw extruder to segmented water cooling, control the temperature of the first segment to 40°C and the second segment to 30°C, and adjust the traction speed of the twin-screw extruder to 30 m / min. In process three, the gradient insulation layer is subjected to interface treatment. Plasma activation is used between the inner and outer layers using oxygen plasma with an activation power of 150W and an activation time of 5s. The peeling force is tested using ASTM D1876 to ensure that the peeling force is ≥50N / cm.

[0008] As a preferred solution of the present invention, in step three, more specifically: The preparation of the self-healing polyurethane layer includes the synthesis of microcapsules: the core material of the microcapsules is caprolactone monomer and initiator BPO, with the ratio of caprolactone monomer and initiator BPO being 95:5, and the wall material of the microcapsules is polyurethane prepolymer and emulsifier Span80, with the ratio of polyurethane prepolymer and emulsifier Span80 being 90:10; The preparation process of microcapsules is as follows: The oil phase and the water phase are stirred at high speed at 50°C, and the emulsion is separated by centrifugation to obtain microcapsules with a particle size of 50 to 200 μm; The spraying process of microcapsules is as follows: The microcapsules were sprayed using an electrostatic sprayer, the equipment model was Wagner ProX 3000; Adjust the equipment parameters of the electrostatic sprayer to 15 kV, flow rate 20 mL / min, and spray gun distance 20 cm; The microcapsules were cured at room temperature for 24 hours, and the humidity was ensured to be ≤40% RH; The performance of the microcapsules was verified as follows: SEM detection showed that the capsules had no agglomeration and the coverage was >95%. The microcapsules were placed in a 60°C constant temperature box for 24 hours, and the crack width recovered from 50μm to <5μm, resulting in a repair rate of >90%.

[0009] As a preferred solution of the present invention, in step 4, more specifically: The material selection of the three-layer co-extruded sheath includes the following materials: The outer layer is made of carbon nanotubes and PI powder, with a ratio of 95:5. The materials of the middle layer are VitonA and graphene, and the ratio of VitonA to graphene is 90:10; The inner layer is made of polyurethane prepolymer and microcapsules, with a ratio of 85:15. The production process of three-layer co-extrusion sheath includes the following processes; Process 1: Select three series extruders as the main equipment; In process 2, the temperature gradient of the three extruders in series was set as follows: outer layer zone I was 160°C, middle layer zone II was 180°C, and inner layer zone III was 200°C; In process 3, the die of the three series extruders is selected as a spiral die head with a compression ratio of 1:1.5 and an aperture of Φ50 mm; Process 4: vacuum shaping is performed at a pressure of -0.09 MPa and a cooling water temperature of 25°C; In process 5, the pulling speed of the three series extruders is set to 20m / min, and the total thickness of the sheath is ≥2.5mm; In process six, the interface fusion of the three-layer co-extruded jacket is completed. The temperature gradient between the layers is increased from 160°C to 200°C through the die head to eliminate delamination. The peel strength is tested using ASTM D1876 to ensure that the peel force is ≥40N / cm.

[0010] As a preferred solution of the present invention, in step five, more specifically: The post-curing heat treatment process includes the following steps: Process 1: Select hot air circulation oven as the main equipment; Process 2: Adjust the parameters of the hot air circulation oven to make the temperature 180℃, the time 2h, and the oxygen content <50ppm; Process 3: Perform cross-linking, self-healing and salt spray resistance tests on the cured material: Cross-linking degree: DSC test shows that the cross-linking degree is ≥85%; Self-repair verification: After SEM observation, the scratched area was heated at 60°C for 2 hours, and the crack repair rate was >90%; Salt spray resistance test: No corrosion for 22,000 hours under ASTM B117 standard.

[0011] Compared with the prior art, the present invention has the following beneficial effects: In the present invention, the feasibility of the core innovation (bionic conductor + gradient sheath) is demonstrated through basic performance verification, and extreme environment tests are conducted to cover typical operating conditions of oil platforms such as low-temperature embrittlement and dynamic loads. The synergistic effect of key parameters (DCP dosage, vulcanization temperature) is clarified through process parameter optimization. The relationship between the quantitative repair efficiency and the triggering conditions is verified through the self-repair mechanism. The technical and economic feasibility is demonstrated through long-term reliability evaluation simulating 3 years of equivalent aging, while meeting core requirements such as wide temperature range stability, mechanical fatigue resistance and chemical corrosion resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a schematic diagram of the components of the cable body of the present invention; Figure 2 This is a flow chart of the preparation method of the high-temperature and low-temperature resistant high-toughness cable material of the present invention. DETAILED DESCRIPTION

[0013] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0014] See also Figure 1-Figure 2 The technical solution provided by the present invention specifically includes the following embodiments: Example: A cable for an oil platform includes a cable body, a bionic twisted conductor is provided in the cable body, a gradient insulation layer is fixedly connected to the surface of the bionic twisted conductor, and a three-layer co-extruded sheath layer is fixedly connected to the surface of the gradient insulation layer; The sheath layer is composed of a carbon nanotube layer, a graphene layer, and a self-healing polyurethane layer from the outside to the inside. The helix angle of the aramid fiber and the tinned copper wire in the bionic twisted conductor is 30° to 45°, and the twisting pitch of the aramid fiber and the tinned copper wire in the bionic twisted conductor is ≤12 times the conductor diameter. The self-repairing polyurethane layer contains caprolactone monomer microcapsules, the capsule particle size of the caprolactone monomer microcapsules is 50 to 200 μm, and the triggering temperature of the caprolactone monomer microcapsules is 60° C. to 80° C.

[0015] The preparation method of high-temperature and low-temperature resistant high-toughness cable material adopts oil platform cable, comprising the following steps: Step 1: Preparation of bionic twisted conductor. In step 1, more specifically: The material selection of bionic stranded conductors includes the following materials: Aramid fiber: DuPont K49 is selected, the linear density of the material is 1.67dtex, the tensile strength of the material is ≥3.6GPa, and the elongation at break of the material is 2.5%; Tinned copper wire: the purity of the material is ≥99.99%, the diameter of the material is 0.25-0.35mm, the thickness of the tin coating is 5-8μm, and the purity of tin is ≥99.3%; Lubricant: Calcium stearate is used, and the amount of lubricant added is 0.5%. The lubricant is used to reduce twisting friction; The stranding process of the bionic stranded conductor includes the following steps: Process 1: Select the CCV continuous vulcanizing unit and adjust the equipment parameters to ensure that the pulling speed is 25m / min, the stranding pitch is ≤12 times the conductor diameter, and the helix angle is 30° to 45°; Process 2: After the bionic twisted conductor is twisted, its surface is treated. After the conductor is twisted, it is treated with argon plasma to make the surface roughness of the bionic twisted conductor Ra ≤ 15nm. The surface of the bionic twisted conductor is then coated with a graphene anti-oxidation coating; Process 3: After the surface treatment of the bionic stranded conductor, it is tested. According to the GB / T3956 standard, the single-wire DC resistance is guaranteed to be ≤0.0172Ω / km at a temperature of 20°C, and the tensile strength is guaranteed to be ≥450MPa after the ASTMD638 test; Step 2: co-extrusion of the gradient insulation layer. In step 2, more specifically: The material selection for the gradient insulation layer includes the following materials: Inner layer: DuPont TF30 is selected, the material thickness is 0.05~0.1mm, and the dielectric strength of the material is ≥17kV / mm; Outer layer: TPV dynamic vulcanization layer is selected, which contains SEBS substrate, POE-g-MAH, nano-silica and dicumyl peroxide. The ratio of SEBS substrate, POE-g-MAH, nano-silica and dicumyl peroxide is 45 parts: 12 parts: 4 parts: 0.8 parts; The production process of the gradient insulation layer includes the following steps: In process 1, a twin-screw extruder is selected as the main equipment. The equipment model is Coperion ZSK32, and the length-to-diameter ratio of the twin-screw extruder is 48:1. Process 2: Adjust the temperature gradient of the twin-screw extruder: in the inner PTFE layer, the temperature of zone I is 280°C, the temperature of the die head is 290°C; in the outer TPV layer, the temperature of zone II is 220°C, and the temperature of the die head is 230°C. Adjust the screw speed of the twin-screw extruder to 300 rpm, set the cooling mode of the twin-screw extruder to segmented water cooling, control the temperature of the first segment to 40°C and the second segment to 30°C, and adjust the traction speed of the twin-screw extruder to 30 m / min. Process three: perform interface treatment on the gradient insulation layer, use plasma activation between the inner and outer layers, use oxygen plasma, activation power of 150W, activation time of 5s, and use ASTMD1876 to test the peel force to ensure that the peel force is ≥50N / cm; Step three: prepare the self-healing polyurethane layer. In step three, more specifically: The preparation of the self-healing polyurethane layer includes the synthesis of microcapsules: the core material of the microcapsules is caprolactone monomer and initiator BPO, with the ratio of caprolactone monomer and initiator BPO being 95:5, and the wall material of the microcapsules is polyurethane prepolymer and emulsifier Span80, with the ratio of polyurethane prepolymer and emulsifier Span80 being 90:10; The preparation process of microcapsules is as follows: The oil phase and the water phase are stirred at high speed at 50°C, and the emulsion is separated by centrifugation to obtain microcapsules with a particle size of 50 to 200 μm; The spraying process of microcapsules is as follows: The microcapsules were sprayed using an electrostatic sprayer, the equipment model was WagnerProX3000; Adjust the equipment parameters of the electrostatic sprayer to 15 kV, flow rate 20 mL / min, and spray gun distance 20 cm; The microcapsules were cured at room temperature for 24 hours, and the humidity was ensured to be ≤40% RH; The performance of the microcapsules was verified as follows: SEM examination showed no agglomeration of the capsules and a coverage rate of >95%. The microcapsules were placed in a 60°C incubator for 24 hours, and the crack width recovered from 50 μm to <5 μm, resulting in a repair rate of >90%. Step 4: forming a three-layer co-extruded sheath. In step 4, more specifically: The material selection of the three-layer co-extruded sheath includes the following materials: The outer layer is made of carbon nanotubes and PI powder, with a ratio of 95:5. The materials of the middle layer are VitonA and graphene, and the ratio of VitonA to graphene is 90:10; The inner layer is made of polyurethane prepolymer and microcapsules, with a ratio of 85:15. The production process of three-layer co-extrusion sheath includes the following processes; In process 1, three series extruders are selected as the main equipment, and the equipment model is CoperionZSK32; In process 2, the temperature gradient of the three extruders in series was set as follows: outer layer zone I was 160°C, middle layer zone II was 180°C, and inner layer zone III was 200°C; In process 3, the die of the three series extruders is selected as a spiral die head with a compression ratio of 1:1.5 and an aperture of Φ50 mm; Process 4: vacuum shaping is performed at a pressure of -0.09 MPa and a cooling water temperature of 25°C; In process 5, the pulling speed of the three series extruders is set to 20m / min, and the total thickness of the sheath is ≥2.5mm; Process 6: Complete the interface fusion of the three-layer co-extruded jacket. Eliminate delamination between layers by adjusting the die temperature gradient from 160°C to 200°C. Test the peel strength using ASTM D1876 to ensure the peel strength is ≥40N / cm. Step five, post-curing treatment, in step five, more specifically: The post-curing heat treatment process includes the following steps: In process 1, the hot air circulation oven is selected as the main equipment, and the equipment model is ESPECSH-261; Process 2: Adjust the parameters of the hot air circulation oven to make the temperature 180℃, the time 2h, and the oxygen content <50ppm; Process 3: Perform cross-linking, self-healing and salt spray resistance tests on the cured material: Cross-linking degree: DSC test shows that the cross-linking degree is ≥85%; Self-repair verification: After SEM observation, the scratched area was heated at 60°C for 2 hours, and the crack repair rate was >90%; Salt spray resistance test: No corrosion for 22,000 hours under ASTM B117 standard.

[0016] Verification 1, basic performance verification (original example): Test conditions: Temperature cycle: -70℃→200℃ cycle 50 times (ASTM E642); Salt spray test: ASTM B117 standard, Cl - Concentration is 5mg / m 3 , lasting 20,000 hours; Tensile strength: ASTM D638 standard, tensile rate is 500 mm / min; Comparing with the existing cables, we get the following comparison table; Verification 2, extreme low temperature performance test: Test conditions: Arctic working condition simulation: -70℃ for 24 hours, superimposed vibration load (5-20Hz, amplitude ±5mm); Adjustment of material ratio: the amount of nano-SiO2 added increased from 4 parts to 6 parts (in SEBS substrate); Comparing with the existing cables, we get the following comparison table; index Measured value <![CDATA[Comparative example (without SiO2)]]> Low temperature brittle temperature -85℃ -60℃ Vibration fatigue life 10,000 times without cracks 2000 cracks Tensile strength retention rate 98％ 75％ Conclusion: Nano-SiO2 improves the low-temperature toughness of the material and reduces the risk of embrittlement.

[0017] Verification three, dynamic vulcanization process optimization: Variable Control: Dosage of curing agent DCP: 0.5% vs 1.0%; Dynamic vulcanization temperature: 180℃ vs 200℃; Comparing with the existing cables, we get the following comparison table; Conclusion: The amount of DCP and the vulcanization temperature need to be optimized synergistically, as excessive DCP will increase the brittleness of the material.

[0018] Verification 4: Self-healing layer trigger temperature verification: Experimental design: Microcapsule triggering temperature: 60℃, 70℃, 80℃; Repair efficiency test: scratch width 50μm, heating time 2h; Comparing with the existing cables, we get the following comparison table; Trigger temperature Repair rate Crack recovery width (μm) 60℃ 92％ 4.5 70℃ 96％ 2.1 80℃ 98％ 0.8 Conclusion: The higher the trigger temperature, the faster the repair efficiency, but too high a temperature (>80℃) may cause local softening of the material.

[0019] Verification 5: Long-term aging performance test: Test conditions: Salt spray + mechanical stress combined aging: Cl - Concentration 10mg / m 3 + Vibration load (20Hz, amplitude ±5mm), lasting for 3 years equivalent time; Sheath material: with self-repairing layer vs traditional polyurethane layer; Comparing with the existing cables, we get the following comparison table; Conclusion: The repair layer significantly delays material aging failure.

[0020] This proposal's preparation method for high-temperature and low-temperature resistant high-toughness cable materials and cables for oil platforms demonstrate the feasibility of the core innovation (bionic conductor + gradient sheath) through basic performance verification during operation. Extreme environment testing covers typical oil platform operating conditions such as low-temperature embrittlement and dynamic loads. Process parameter optimization identifies the synergistic effect of key parameters (DCP dosage, vulcanization temperature). The relationship between the quantitative repair efficiency and triggering conditions is verified through the self-repair mechanism. Long-term reliability evaluation simulates 3 years of equivalent aging to demonstrate the technical and economic feasibility.

[0021] While the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations can be made to the embodiments without departing from the principles and spirit of the invention.

Claims

1. Cable for oil platform, characterized by: The cable comprises a cable body, wherein a bionic twisted conductor is provided in the cable body, a gradient insulation layer is fixedly connected to the surface of the bionic twisted conductor, and a three-layer co-extruded sheath layer is fixedly connected to the surface of the gradient insulation layer; The sheath layer comprises a carbon nanotube layer, a graphene layer, and a self-healing polyurethane layer from the outside to the inside. The helical angle between the aramid fiber and the tinned copper wire in the bionic twisted conductor is 30° to 45°, and the twisting pitch between the aramid fiber and the tinned copper wire in the bionic twisted conductor is ≤12 times the conductor diameter. The self-repairing polyurethane layer contains caprolactone monomer microcapsules, the capsule particle size of the caprolactone monomer microcapsules is 50-200 μm, and the triggering temperature of the caprolactone monomer microcapsules is 60° C.-80° C.

2. A method for preparing a high-temperature and low-temperature resistant high-toughness cable material, using the oil platform cable described in claim 1, characterized in that: The following steps are involved: Step 1: Preparation of bionic twisted conductor; Step 2: co-extrusion of the gradient insulation layer; Step 3: Preparation of self-repairing polyurethane layer; Step 4: three-layer co-extrusion sheath molding; Step five: post-curing treatment.

3. The method for preparing a high-temperature and low-temperature resistant high-toughness cable material according to claim 2, characterized in that: In step one, more specifically: The material selection of bionic stranded conductors includes the following materials: Aramid fiber: The linear density of the material is 1.67dtex, the tensile strength of the material is ≥3.6GPa, and the elongation at break of the material is 2.5%; Tinned copper wire: the purity of the material is ≥99.99%, the diameter of the material is 0.25~0.35mm, the thickness of the tin coating is 5~8μm, and the purity of tin is ≥99.3%; Lubricant: Calcium stearate is used, and the amount of lubricant added is 0.5%. The lubricant is used to reduce twisting friction; The stranding process of the bionic stranded conductor includes the following steps: Process 1: Select the CCV continuous vulcanizing unit and adjust the equipment parameters to ensure that the pulling speed is 25m / min, the stranding pitch is ≤12 times the conductor diameter, and the helix angle is 30°~45°; Process 2: After the bionic twisted conductor is twisted, its surface is treated. After the conductor is twisted, it is treated with argon plasma to make the surface roughness of the bionic twisted conductor Ra ≤ 15nm. The surface of the bionic twisted conductor is then coated with a graphene anti-oxidation coating; Process three: After the surface treatment of the bionic twisted conductor, it is tested. According to the GB / T 3956-2021 standard, the single-line DC resistance is guaranteed to be ≤0.0172Ω / km at a temperature of 20°C, and the tensile strength is guaranteed to be ≥450MPa after ASTMD638 testing.

4. The method for preparing a high-temperature and low-temperature resistant high-toughness cable material according to claim 2, characterized in that: In step 2, more specifically: The material selection for the gradient insulation layer includes the following materials: Inner layer: The thickness of the material is 0.05~0.1mm, and the dielectric strength of the material is ≥17kV / mm; Outer layer: TPV dynamic vulcanization layer is selected, which contains SEBS substrate, POE-g-MAH, nano-silica and dicumyl peroxide. The ratio of SEBS substrate, POE-g-MAH, nano-silica and dicumyl peroxide is 45 parts: 12 parts: 4 parts: 0.8 parts; The production process of the gradient insulation layer includes the following steps: In process 1, a twin-screw extruder is selected as the main equipment, and the length-to-diameter ratio of the twin-screw extruder is 48:1; Process 2: Adjust the temperature gradient of the twin-screw extruder: in the inner PTFE layer, the temperature of zone I is 280°C, the temperature of the die head is 290°C; in the outer TPV layer, the temperature of zone II is 220°C, and the temperature of the die head is 230°C. Adjust the screw speed of the twin-screw extruder to 300 rpm, set the cooling mode of the twin-screw extruder to segmented water cooling, control the temperature of the first segment to 40°C and the second segment to 30°C, and adjust the traction speed of the twin-screw extruder to 30 m / min. In process three, the gradient insulation layer is subjected to interface treatment. Plasma activation is used between the inner and outer layers using oxygen plasma with an activation power of 150W and an activation time of 5s. The peeling force is tested using ASTM D1876 to ensure that the peeling force is ≥50N / cm.

5. The method for preparing a high-temperature and low-temperature resistant high-toughness cable material according to claim 2, characterized in that: In step three, more specifically: The preparation of the self-healing polyurethane layer includes the synthesis of microcapsules: the core material of the microcapsules is caprolactone monomer and initiator BPO, with the ratio of caprolactone monomer and initiator BPO being 95:5, and the wall material of the microcapsules is polyurethane prepolymer and emulsifier Span80, with the ratio of polyurethane prepolymer and emulsifier Span80 being 90:10; The preparation process of microcapsules is as follows: The oil phase and the water phase are stirred at high speed at 50°C, and the emulsion is separated by centrifugation to obtain microcapsules with a particle size of 50-200 μm; The spraying process of microcapsules is as follows: The microcapsules are sprayed using an electrostatic sprayer; Adjust the equipment parameters of the electrostatic sprayer to 15 kV, flow rate 20 mL / min, and spray gun distance 20 cm; The microcapsules were cured at room temperature for 24 hours, ensuring that the humidity was ≤40% RH; The performance of the microcapsules was verified as follows: SEM detection showed that the capsules had no agglomeration and the coverage was >95%. The microcapsules were placed in a 60°C constant temperature box for 24 hours, and the crack width recovered from 50μm to <5μm, resulting in a repair rate of >90%.

6. The method for preparing a high-temperature and low-temperature resistant high-toughness cable material according to claim 2, characterized in that: In step 4, more specifically: The material selection of the three-layer co-extruded sheath includes the following materials: The outer layer is made of carbon nanotubes and PI powder, with a ratio of 95:

5. The materials of the middle layer are VitonA and graphene, and the ratio of VitonA to graphene is 90:10; The inner layer is made of polyurethane prepolymer and microcapsules, with a ratio of 85:

15. The production process of three-layer co-extrusion sheath includes the following processes; Process 1: Select three series extruders as the main equipment; In process 2, the temperature gradient of the three extruders in series was set as follows: outer layer zone I was 160°C, middle layer zone II was 180°C, and inner layer zone III was 200°C; In process 3, the die of the three series extruders is selected as a spiral die head with a compression ratio of 1:1.5 and an aperture of Φ50 mm; Process 4: vacuum shaping is performed at a pressure of -0.09 MPa and a cooling water temperature of 25°C; In process 5, the pulling speed of the three series extruders is set to 20m / min, and the total thickness of the sheath is ≥2.5mm; In process six, the interface fusion of the three-layer co-extruded jacket is completed. The temperature gradient between the layers is increased from 160°C to 200°C through the die head to eliminate delamination. The peel strength is tested using ASTM D1876 to ensure that the peel force is ≥40N / cm.

7. The method for preparing a high-temperature and low-temperature resistant high-toughness cable material according to claim 2, characterized in that: In step five, more specifically: The post-curing heat treatment process includes the following steps: Process 1: Select hot air circulation oven as the main equipment; Process 2: Adjust the parameters of the hot air circulation oven to make the temperature 180℃, the time 2h, and the oxygen content <50ppm; Process 3: Perform cross-linking, self-healing and salt spray resistance tests on the cured material: Cross-linking degree: DSC test shows that the cross-linking degree is ≥85%; Self-repair verification: After SEM observation, the scratch area was heated at 60°C for 2 hours, and the crack repair rate was >90%; Salt spray resistance test: No corrosion for 22,000 hours under ASTM B117 standard.

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