High temperature resistant and bending resistant ethylene propylene rubber insulated cable for rail transit, preparation method and insulating material

Abstract

The invention discloses a high temperature resistant and bending resistant ethylene propylene rubber insulated cable for rail transit and a preparation method thereof, comprising a conductor, wherein the first polyetheretherketone film sheath and the second polyetheretherketone film sheath are sequentially wrapped around the conductor, a 150°C low smoke halogen-free flame retardant modified irradiated ethylene propylene rubber insulation layer is extruded between the first polyetheretherketone film sheath and the second polyetheretherketone film sheath, a polyimide film sheath is wrapped after a Twaron aramid fiber yarn braided reinforcement layer is woven outside the second polyetheretherketone film sheath, a ZS-322 transparent high temperature resistant heat insulation coating is coated on the outer surface of the polyimide film sheath and dried to form a high temperature resistant heat insulation coating layer, and a high toughness heat resistant and wear resistant polyvinylidene fluoride outer sheath is extruded outside the high temperature resistant heat insulation coating layer. The cable has excellent mechanical properties, electrical properties, high temperature resistance, and good flame retardant properties.

Description

Technical Field

[0001] The invention relates to the field of cables and cable materials, and in particular to a high-temperature resistant and bending resistant ethylene-propylene rubber insulated cable for rail transit, a preparation method of the cable and an insulating material. Background Art

[0002] The 21st century is a period of rapid development of urban rail transit in my country (including subways, ground light rails, and elevated light rails). Compared with other means of transportation, subways have the characteristics of fast driving speed, large passenger transport volume, no ground space occupation, environmental protection and no exhaust emissions. It is an effective way to solve the current urban traffic congestion and air pollution caused by exhaust emissions. With the rapid development of cities, the increasing complexity of functions and the sharp increase in population, it is urgent to build a fast underground rail transit network. Cables for 1500V and below DC traction systems of rail transit have been widely used as important supporting products. At present, the rail transit DC traction cable used in rail transit traction system is mainly cross-linked polyethylene insulated cable. The main problems exposed by this cable during use are: the insulation is made of cross-linked polyethylene, the material is relatively hard, and cross-linked polyethylene is not water-resistant. If it is exposed to water vapor for a long time, it is easy to cause water tree breakdown. Therefore, in order to prevent water vapor from entering, an aluminum-plastic composite tape polyethylene waterproof layer is used on the outside of the cable core, making the cable more difficult to bend. The laying environment of rail transit cables is generally relatively narrow, especially in subway tunnels. This will inevitably cause the cable to bend excessively when used in a small space, causing damage to the internal insulation and components of the cable. Finally, after the cable has been running for a period of time, various accidents such as breakdown will occur, and the reliability and service life of the cable will be greatly reduced.

[0003] However, due to the large passenger flow in rail transit and the limited volume inside the carriage, the cables used in rail transit will be entangled, pulled, and bent during laying. When the vehicle is in operation, the cables are entangled together, which is not conducive to heat dissipation. When the outside temperature is high, the cables are prone to aging, breakage, and deformation, which seriously affects the electrical performance and service life of the cables.

[0004] Since the advent of EPDM in 1962, it has been valued by the cable industry for its excellent resistance to ozone, weathering and heat aging, good electrical insulation, heat deformation and chemical corrosion, low relative density and large filling volume. At present, it has replaced traditional styrene-butadiene, natural and butyl rubbers and has been widely used in medium and high voltage cables for ships and mobile use. However, like most hydrocarbon polymer compounds, EPDM is also very flammable, and the oxygen index of pure rubber is only about 19. In addition, the current cables generally have poor cold resistance and are easy to become brittle. Therefore, the development of highly cold-resistant and flame-retardant EPDM cable materials has received attention from the cable industry. EPDM is a polymer composed of propylene, ethylene and conjugated diene. Since the carbon atoms on its main chain are in a saturated structure and only a few unsaturated carbon atoms on the side chain, it has many excellent processing properties and use properties, such as low density, weather resistance, heat resistance and ozone resistance, excellent mechanical properties, etc.; but EPDM also has disadvantages such as oil resistance, poor adhesion, and slow vulcanization speed. With the rapid development of the world's industry, the requirements for the quantity and especially the quality of EPDM are getting higher and higher. Modifying EPDM to meet the actual technical requirements of modern society is a hot topic of current research. EPDM (EPDM) is widely used as insulation or sheath material for wires and cables due to its excellent electrical properties, excellent heat resistance and aging resistance, and good low-temperature flexibility. The traditional cross-linking methods for the insulation or sheath layer of EPDM wires and cables mainly include peroxide chemical cross-linking method, high-energy radiation cross-linking method and silane cross-linking method.

[0005] European patent EP1453866 discloses the preparation of cross-linked EPDM rubber soft cable under chemical cross-linking conditions initiated by heat from diisopropylbenzene peroxide using a material system consisting of EPDM, calcined kaolin, low-density polyethylene, silane coupling agent and paraffin. The tensile strength of the product is greater than 8.2MPa and the elongation at break is greater than 250%. U.S. Patent US2004242781 discloses the preparation of EPDM rubber cable by chemical cross-linking using EPDM, kaolin, organic peroxide, zinc oxide, paraffin oil and antioxidant. The tensile strength of the product is greater than 9MPa and the elongation at break is greater than 200%.

[0006] Chinese patent publication number CN1783356 discloses a composite material system of EPDM, calcined clay, antioxidant, organic peroxide, coupling agent and paraffin wax, which is prepared by chemical crosslinking method for medium-voltage EPDM rubber insulated cable, and the product has a tensile strength greater than 6MPa and an elongation at break greater than 300%.

[0007] China's "Elastomer" magazine (Issue 5, 2006, page 51) described the preparation of EPDM rubber cable by chemical cross-linking method using EPDM, calcium carbonate, kaolin, talcum powder, diisopropylbenzene peroxide, softener and antioxidant. The tensile strength of the product is greater than 5MPa and the elongation at break is higher than 350%.

[0008] The Chinese magazine "New Chemical Materials" (Volume 34, Issue 1, Page 57, 2006) reported that EPDM rubber materials were prepared using nano-silicon dioxide and nano-calcium carbonate as reinforcing fillers and a high-energy radiation cross-linking method. The tensile strength of the resulting product can reach a maximum of 12 MPa, and the elongation at break is greater than 400%.

[0009] Radiation Physics Chemistry (Radiation Physics Chemistry, 1983, 22 (3-5), 564-74) describes a rubber insulating material composed of high-ethylene-content EPDM rubber, ethylene-vinyl acetate copolymer and antioxidant, which is cross-linked by electron beam irradiation, and the product has excellent aging resistance and electrical properties.

[0010] Chinese patent publication number CN1058507C discloses the preparation of cross-linked mining rubber soft cable by radiation cross-linking method using EPDM rubber, low-density polyethylene, light calcium carbonate, decabromodiphenyl ether, molybdenum oxide, radiation cross-linking agent, etc. The product has high temperature resistance and excellent mechanical and electrical properties.

[0011] Chinese patent application No. 200910172429 discloses a method for preparing cross-linked EPDM cable material by using EPDM, compound silane, catalyst, lubricant, etc., and adopting silane cross-linking method. The cable material can be cross-linked at a relatively fast speed in 90°C water, and the thermal elongation is ≤80%.

[0012] However, the disadvantages of the peroxide chemical crosslinking method for preparing EPDM rubber cables in the above-mentioned various methods are low production efficiency and complex process flow. It needs to be crosslinked for a long time through a high-pressure and high-temperature steam vulcanization pipeline of several tens of meters, which consumes a lot of energy and has a very low energy efficiency. The effective utilization rate of its heat energy is only about 10%, etc., and it has very high requirements for plant design, manufacturing equipment, etc., and the investment is also large, especially the technical level of the manufacturing personnel is extremely high. Since the sulfur-linking pipeline is closed when the machine is turned on, the appearance of the cable cannot be observed intuitively, so the product quality is difficult to control, the yield is low, the manufacturing waste is large, and the production of small-section cables is even more difficult. Moreover, the temperature resistance level can only reach 90°C, which is not conducive to the production of EPDM rubber insulated rail transit vehicle cables; the high-energy radiation crosslinking method has a high equipment investment, complex operation and maintenance, and harsh protection conditions. In addition, due to its process characteristics, it is only suitable for making wires with smaller wire diameters but not for cables with larger wire diameters; and the silane crosslinking method involves a hydrolysis reaction, and the stability of the product is poor, and the pressure and temperature resistance level is also low. Summary of the invention

[0013] In order to solve the problems existing in the prior art, the present invention provides a high temperature resistant and bending resistant ethylene propylene rubber insulated cable for rail transit, a preparation method of the cable and an insulating material.

[0014] The high-temperature-resistant and bending-resistant EPDM insulated cable for rail transit described in the present invention comprises a conductor, a first polyetheretherketone film sheath and a second polyetheretherketone film sheath are sequentially wrapped around the outside of the conductor, a 150°C low-smoke halogen-free flame-retardant modified irradiated EPDM insulation layer is extruded between the first polyetheretherketone film sheath and the second polyetheretherketone film sheath, a Twaron aramid fiber woven reinforcement layer is woven outside the second polyetheretherketone film sheath and then wrapped with a polyimide film sheath, a ZS-322 transparent high-temperature-resistant heat-insulating coating is coated on the outer surface of the polyimide film sheath and dried to form a high-temperature-resistant heat-insulating coating layer, and a high-toughness, heat-resistant and wear-resistant polyvinylidene fluoride outer sheath is extruded outside the high-temperature-resistant heat-insulating coating layer.

[0015] As a further improvement, the conductor is a Category 6 soft copper conductor.

[0016] A method for preparing a high temperature resistant and bending resistant ethylene propylene rubber insulated cable for rail transit, comprising the following steps:

[0017] 1) Preparation of conductor:

[0018] 1-1) Wire drawing: First, a copper rod with a diameter of 3mm is drawn into a copper wire with a diameter of 0.99mm on a LT2-15 / 350 copper wire drawing machine. The sizes of the wire drawing dies are: 2.76, 2.55, 2.35, 2.16, 1.99, 1.83, 1.69, 1.56, 1.43, 1.32, 1.02mm; the copper wire outlet speed is 10-20m / s, and the maximum annealing voltage is The current is 1200A; then the copper wire with a diameter of 0.99mm is drawn into a copper wire with a diameter of 0.3-0.5mm on the LHT-200 / 17 copper small drawing machine wire. The sizes of the wire drawing dies can be: 0.83, 0.74, 0.65, 0.59, 0.52, 0.46, 0.40, 0.35, 0.31mm, the copper wire emergence speed is 8-16m / s, and the maximum annealing current is 600A;

[0019] 1-2) Wire bundling: 23 to 63 copper wires with a diameter of 0.3 to 0.5 mm are bundled into strands by a DF-GJ / 500 type wire bundling machine, the bundle pitch ratio range is 20 to 30, the bundle outer diameter is 1.15 to 3.26 mm, the gear shift range is Z1: 33 to 50, Z2: 30 to 47, and the bundle speed is 5 to 45 m / min;

[0020] 1-3) Strand re-twisting: The 7 to 61 strands of wire are re-twisted on a LLY500 / 30 cage stranding machine in a 1+6+12+18+24 arrangement to form a soft copper conductor of the sixth category structure in accordance with the standard GB / T3956-2008. The re-twisted outer diameter is 3.4 to 29.6 mm. When the structure is 1+6+12, the ratio of the second and third layer diameters is set to be no more than 25 and 14; when the structure is 1+6+12+18, the ratio of the second, third, and fourth layer diameters is set to be no more than 25, 20, and 14;

[0021] 2) The first polyetheretherketone film wrapping process: directly wrap the polyetheretherketone film with a thickness of 0.1-0.2mm and a width of 35-55mm on the outside of the conductor through an LLY500 / 30 type cage stranding machine, and then wind it up on the coil, using a single-layer overlapping wrapping method, with the overlap rate controlled at 15-30%, and the wrapping angle at 15-45°. The outer diameter of the cable core after wrapping is calculated according to the formula "outer diameter before wrapping + number of layers × 3 × wrapping tape thickness", and is controlled at 3.7-30.2mm;

[0022] 3) 150℃ low-smoke halogen-free flame-retardant modified irradiated EPDM rubber insulation layer extrusion process: The cable conductor wrapped with polyetheretherketone film is extruded through SJ-45 / 25~120 / 25 type extruder to complete the 150℃ low-smoke halogen-free flame-retardant modified irradiated EPDM rubber insulation layer and obtain the insulated wire core. The heating temperature of the extruder barrel in the first to sixth zones is 100±5℃, 110±5℃, 115±5℃, 125±5℃, 135±5℃, 140±5℃ respectively; the head flange heating temperature is 145±5℃; the mold heating temperature in the first to third zones is 155±5℃, 165±5℃, 175 ±5℃; 150℃ low smoke halogen-free flame retardant modified irradiated EPDM insulation material is melted to molten state and filtered through two layers of filter screens with 60 mesh and 120 mesh; the mold adopts an extrusion tube mold, which can make full use of the stretchability of the modified EPDM insulation material to improve the extrusion quality. The mold core matching range is 5-35mm, and the mold sleeve matching range is 10-45mm; the nominal insulation thickness is 0.7-2.0mm, and the thinnest point is not less than 90%-0.1mm of the nominal value according to the formula, and is controlled at 0.53-1.7mm; the outer diameter of the insulation core ranges from 5.5 to 34.5mm; the traction speed is controlled at 20-80m / min;

[0023] 3-1) The surface of the extruded insulated wire core should be smooth without pores and impurities and be water-cooled in a 25-meter-long constant temperature water tank. After the insulated wire core exits the water tank, it is dried with a hot air drying device, and then passes a 10-25kV spark test as an intermediate inspection. It is then pulled to the cable drum to complete the 150°C low-smoke, halogen-free, flame-retardant, modified irradiated ethylene-propylene rubber insulation layer extrusion process;

[0024] 3-2) Winding the insulated wire core on the inner traction in a racetrack winding manner, and completing electron beam irradiation through a CELV-8 electron accelerator in a circular irradiation process to obtain an irradiated insulated wire core; the accelerator energy range is 1.0 to 2.5 MeV, the beam current range is 10 to 60 mA, and the power range is 60 to 100 kW;

[0025] 4) Wrapping process of the second polyetheretherketone film: Wrap the insulated wire core with a polyetheretherketone film with a thickness of 0.1-0.2 mm and a width of 35-55 mm on a JLC-500 / 1+12 type fork twisting machine or a CLY-1250 / 1+6 type cabling machine, using a double-layer gap wrapping mode, the first layer gap type is left-handed, the second layer gap type is right-handed, the gap rate is 2-5%, the wrapping angle is 15-45°, and the outer diameter after wrapping is calculated according to the formula "outer diameter before wrapping + number of layers × 2 × wrapping tape thickness", and is controlled within 5.9-35.3 mm;

[0026] 5) Weaving process of Twaron aramid fiber braided reinforcement layer: twist 4 to 9 Twaron aramid fiber strands with a diameter of 0.1 to 0.2 mm into strands, and then weave the strands on a HGSB-16 spindle braiding machine or a GSB-1A / 24 spindle braiding machine to form a Twaron aramid fiber braided reinforcement layer. The braided reinforcement layer is not allowed to be welded as a whole, the braiding should be uniform, the surface broken wires should be trimmed, and the fiber spindles should not be replaced more than once per meter length; the braiding density is controlled at 75 to 85%, the pitch is 10 to 40 mm, the braiding angle is 15 to 45°, and the outer diameter of the cable core after braiding is calculated according to the formula "outer diameter before braiding + 4×fiber monofilament diameter" and is controlled at 6.3 to 36.1 mm;

[0027] 6) Wrapping process of polyimide film: After the Twaron aramid fiber filament braided reinforcement layer, directly wrap the polyimide film with a thickness of 0.04-0.08 mm and a width of 35-60 mm, using a single-layer overlapping wrapping mode, with the overlap rate controlled at 20-35%, and the reference outer diameter after wrapping is calculated according to the formula "outer diameter before wrapping + number of layers × 3 × wrapping tape thickness", and is controlled at 6.5-36.4 mm;

[0028] 7) Process of ZS-322 transparent high temperature resistant heat insulation coating: The cable core wrapped with polyimide film is passed through the 360° automatic spraying equipment horizontally and slowly at a uniform speed. A hot air drying device is placed in front of the equipment to clean the dust, grease, moisture and other impurities on the surface of the cable core to ensure balanced coating. The overall spraying thickness is 100-150μm;

[0029] 7-1) After spraying, the cable enters the drying device, the drying temperature is 60-70℃, the oven length is 2 meters, and the drying speed is 2m / min, so that the cable can stay in the drying device for 1 minute to ensure that the coating is dry and no impurities adhere to it;

[0030] 7-2) After coating, the cable core will be sent to a constant temperature drying room at 50°C and placed for 24 hours;

[0031] 8) Extrusion process of high-toughness, heat-resistant and wear-resistant polyvinylidene fluoride outer sheath: After drying, the cable core is extruded through a SJ-90 / 25~150 / 25 extruder to complete the extrusion of the high-toughness, heat-resistant and wear-resistant polyvinylidene fluoride outer sheath, wherein the heating temperatures of the extruder barrel in the first to sixth zones are 180±5℃, 180±5℃, 185±5℃, 190±5℃, 195±5℃, 200±5℃ respectively; the heating temperature of the head flange is 205±5℃; the heating temperature of the mold in the first to third zones is 205±5℃, 210±5℃, 215±5℃ respectively; The olefin sheath material needs to be filtered through three layers of 40 mesh, 60 mesh and 100 mesh when it is melted to a molten state; the screw speed is 30-40r / min, and the extrusion speed is controlled at 10-30m / min; the mold core matching range is 10-40mm, and the mold sleeve matching range is 20-50mm; the nominal thickness of the sheath should be calculated according to the formula "0.035× cable core outer diameter before extrusion + 1.0mm", and controlled at 1.4-3.0mm, and the thinnest point should be no less than 80%-0.2mm of the nominal value according to the formula, and controlled at 0.92-2.2mm; the cable outer diameter range is 9.5-43mm;

[0032] 8-1) The surface of the extruded cable should be smooth without pores and impurities and be cooled by water in a 25-meter-long constant temperature water tank. After the cable comes out of the water tank, it should be dried by a hot air drying device and then pass a 15-25kV spark test as an intermediate inspection;

[0033] 8-3) Finally, the product logo is sprayed on the surface of the cable outer sheath by a printer, and then the finished cable is pulled onto the cable drum by a crawler tractor to complete the outer sheath extrusion process.

[0034] A 150°C low-smoke halogen-free flame-retardant modified irradiated ethylene-propylene rubber insulation material, comprising the following components in parts by mass:

[0035] EPDM rubber: 45-55 parts

[0036] Ultrafine polyimide resin powder: 18-25 parts

[0037] Plasticizer: 5-10 parts

[0038] Graphene: 1-5 parts

[0039] White oil: 3-8 parts

[0040] Maleic anhydride: 1-2 parts

[0041] Cross-linking agent: 1-3 parts

[0042] Magnesium hydroxide inorganic flame retardant: 5-10 parts

[0043] Surface treatment agent: 0.1-0.5 parts

[0044] Antioxidant and anti-copper agent 1024: 0.3-0.8 parts

[0045] Lubricant: 0.5-1 part.

[0046] According to a further improvement, the plasticizer is dioctyl phthalate.

[0047] In a further improvement, the cross-linking aid is trimethylolpropane trimethacrylate.

[0048] Further improvement, the surface treatment agent is RCA aluminate coupling agent.

[0049] Further improvement, the lubricant is zinc stearate.

[0050] Compared with the prior art, the present invention has the following beneficial effects:

[0051] Compared with the existing structure, the structure of the present invention has the following advantages:

[0052] 1. Use Category 6 soft copper conductor, which is resistant to bending and has a large bending radius;

[0053] 2. The conductor is wrapped with polyetheretherketone film, which makes the cable have excellent mechanical properties, electrical properties, high temperature resistance (mechanical strength does not decrease at a high temperature of 240°C), good flame retardancy: high flame retardancy without the use of flame retardant additives, excellent electrical insulation performance: high dielectric strength, stable dielectric properties under various temperatures, frequencies and temperature conditions, radiation resistance, hydrolysis resistance and wide chemical resistance: insoluble in all common solvents - excellent acid, alkali resistance, lubricating oil resistance, excellent barrier properties and low moisture absorption;

[0054] 3. The 150℃ low-smoke halogen-free flame-retardant modified irradiated EPDM rubber insulation layer is made of EPDM rubber resin combined with ultra-fine polyimide resin, so that the long-term heat resistance level of the insulation material can be increased to above 150℃, and it has excellent electrical insulation, flame retardancy, flexibility (bending resistance), heat resistance, wear resistance, melt fluidity, and resistance to mineral oil and fuel oil;

[0055] 4. The Twaron aramid fiber braided reinforcement layer has high strength (excellent strength-to-weight ratio), high modulus, high dimensional stability, excellent heat resistance, chemical resistance, no melting point (degradation only occurs when the temperature reaches 500°C), and is non-flammable;

[0056] 5. The polyimide film sheath has excellent high temperature resistance, radiation resistance, chemical corrosion resistance and mechanical properties. It can be used for a long time in air at 250-280°C, and polyimide can prevent combustion without adding flame retardants. It forms an inner, middle and outer three-layer flame retardant structure with two layers of polyetheretherketone film, making the flame retardant performance of the cable dozens or even hundreds of times better than the existing ones.

[0057] 6. Apply ZS-322 transparent high temperature resistant heat insulation coating to form a coating layer, which increases the temperature resistance of the cable by more than 10%, making the cable resistant to open flames, and the fire retardant grade reaches Class A, with good acid and alkali resistance, antioxidant performance and good adhesion;

[0058] 7. The outermost layer of the cable adopts high-toughness, heat-resistant and wear-resistant polyvinylidene fluoride outer sheath, which makes the cable have excellent heat resistance, strongest toughness, low friction coefficient, strong corrosion resistance, aging resistance, weather resistance, and good radiation resistance.

[0059] Compared with the existing technology, the technology of the present invention has the following advantages:

[0060] 1. The long-term rated heat resistance level of this cable can be increased to 150℃ and above, breaking through the limitation of the maximum heat resistance level of 90℃ in the steam vulcanization process, and the cable has a wider range of adaptation; at the same time, the cable with the same cross-section conductor allows a larger current carrying capacity, more room for maximum operating temperature surplus, more reliable operation, longer service life, bending resistance, and a large bending radius; when the conductor adopts a 1+6+12 stranded wire double-twisted structure, the second and third layer pitch ratios are set to be no more than 25 and 14; when the stranded wire double-twisted structure is 1+6+12+18, the second, third, and fourth layer pitch ratios are set to be no more than 25, 20, and 14;

[0061] 2. The product quality of the cable can be controlled continuously and economically during the production process. Compared with the production process using continuous steam vulcanization pipelines, this set of manufacturing process for producing EPDM insulated cables uses ordinary low-compression ratio extrusion equipment, which has very low energy consumption itself, and the entire production process is completed in a visible environment. If an abnormality occurs, the machine can be shut down, and production can be quickly resumed after the abnormality is eliminated, without batch scrapping or even missing quality risks. The continuous steam vulcanization pipeline production process completes the EPDM extrusion and vulcanization process in a fully closed state, and the state after molding can only be confirmed at the pipeline outlet. Once an abnormality occurs, the machine must be shut down and wait for cooling before finding the cause and eliminating the abnormality. Not only is working time wasted, but the semi-finished products in the nearly 100-meter pipeline will become waste. The most critical thing is that a lot of preparation work must be done before production can be resumed, not to mention the energy consumption of steam boilers that have no output value during the production suspension process, and all of these will be in this set. The process method is controlled to the greatest extent and in the most economical way. The steam boiler uses coal to burn water to produce water vapor, and the coal will then produce sulfur dioxide, nitrogen oxidation, etc. in the process. These gases dissolve in water to form acid rain, which will corrode forests and buildings. When the coal is burning, small solid particles will also be produced, causing dust pollution in the air. This process uses an extruder for extrusion, and does not require steam vulcanization, thus avoiding the impact of steam pipe vulcanization on insulation performance, and does not require high-temperature steam and long continuous vulcanization pipelines. The manufacturing process is simple and uses less equipment, saving resources such as water, electricity, and gas, with almost no impact on the environment and low production cost. In the step process, a hot air drying device is used to dry the insulated wire core after it comes out of the water tank, and then a 10-25kV spark test is used as an intermediate inspection to determine whether the thinnest point of the insulation and the sheath is damaged, and whether there is a problem of non-compliance, thereby avoiding subsequent detection of problems and greater economic losses.

[0062] 3. Streamlining the process flow, doubling the production efficiency, and significantly reducing labor costs; the continuous steam vulcanization pipeline production process requires at least 6 people including the captain, assistant operator, glue feeder, wire laying worker, wire take-up worker, boiler operator, etc., and 10 people are needed to complete the insulation and sheathing; in comparison, this set of technology reduces labor costs by at least 50%.

[0063] 4. Improve the design of conductors and wrapping processes to improve efficiency while reducing costs and energy consumption; the cable conductor adopts a bundled wire + double-twisted structure, which enlarges the pitch while meeting the conductor DC resistance, and reduces the conductor cross-section by 0.2% to 0.9%; the production speed can be increased by 6% at the same cage speed, and the efficiency is improved; the cage speed is reduced by 6 to 7% at the same production speed, and energy consumption is reduced; the wrapping tape adopts a single-layer overlap and double-layer gap wrapping process, and the outer diameter after wrapping is slightly smaller than the outer diameter after double-layer overlap wrapping in the past, which directly reduces the material consumption of the subsequent processes.

[0064] The 150°C low-smoke halogen-free flame-retardant modified irradiated ethylene-propylene rubber insulation material developed by the present invention has the following advantages compared with the existing ones:

[0065] Ultrafine polyimide resin powder is used, which is a flame-retardant polymer that does not burn at high temperatures. It has excellent thermal properties and a long-term use temperature of -200 to 426°C. When combined with EPDM rubber resin, the long-term heat resistance level of the insulation material can be increased to above 150°C. It has excellent electrical insulation, flame retardancy, flexibility (bending resistance), heat resistance, wear resistance, melt fluidity, and resistance to mineral oil and fuel. The polymer of EPDM rubber resin and ultrafine polyimide resin powder is combined with dioctyl phthalate to reduce the flow viscosity of the polymer at high temperatures, increase plasticity and elasticity, and improve low-temperature brittleness. Increase softness, improve physical and mechanical properties, chemical properties, dielectric properties and processing performance; Graphene combined with white oil allows graphene to be evenly dispersed in the insulating material, improving the mechanical properties of the insulating material. Because graphene has thermal stability, the mechanical properties of the insulating material can be kept stable under high temperature conditions. If it is not combined with white oil, the graphene added alone cannot be evenly dispersed in the insulating material, which will make the later insulating material unstable in mechanical properties, poor color and easy to crack under high temperature conditions. On the basis of combining graphene with white oil, combined with trimethylolpropane trimethacrylate, the thermal stability of the insulating material can be improved. The corrosion resistance and aging resistance of the insulating material after the introduction of graphene are improved, and the hardness and heat resistance are improved, the radiation dose is reduced, the radiation time is shortened, the cross-linking density is increased, and it has the characteristics of low viscosity, high cross-linking degree, low steam pressure and fast curing speed; maleic anhydride is used as the grafting monomer, and the EPDM rubber is grafted and modified by irradiation technology to increase its polarity, thereby improving its compatibility with polar polymers; magnesium hydroxide inorganic flame retardant is added, and magnesium hydroxide has the triple functions of flame retardant, smoke elimination and filling, which makes the insulating material smokeless and non-corrosive, and can obtain better flame retardant and smoke elimination effects. It can show good Good flame retardant synergistic effect; adding RCA aluminate coupling agent (surface treatment agent) to use the groups of the coupling agent molecules to react with the surface of magnesium hydroxide to form chemical bonds, thereby improving the compatibility with high molecular polymers; adding antioxidants and anti-copper agents to have a synergistic effect with other materials, which can prevent the oxidation and decomposition of insulating materials, and effectively inhibit the catalytic aging of heavy metal ions on polymer materials, thereby extending the service life of insulating materials; zinc stearate is added to the insulating material to form a smooth interface during the processing of the insulating material, thereby reducing friction, while reducing the melt viscosity of the insulating material and improving the processing performance of the insulating material. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figure 1 It is a structural schematic diagram of the present invention;

[0067] Figure 2This is an electron microscope image at 5 μm without adding graphene to the insulating material;

[0068] Figure 3 This is an electron microscope image of graphene added to insulating material at 5μm;

[0069] Figure 4 This is an electron microscope image of graphene added to insulating material at 10μm;

[0070] Figure 5 This is an electron microscope image at 100μm showing graphene added to insulating material. DETAILED DESCRIPTION

[0071] The present invention will be further described below in conjunction with the accompanying drawings.

[0072] Embodiment 1:

[0073] like Figure 1The high temperature and bending resistant EPDM insulated cable for rail transit shown in the figure comprises a conductor 1, which is a Class VI soft copper conductor, resistant to bending and with a large bending radius; the first polyetheretherketone film sheath 2 and the second polyetheretherketone film sheath 4 are sequentially wrapped around the outside of the conductor, so that the cable has excellent mechanical properties, electrical properties, high temperature resistance (mechanical strength does not decrease at a high temperature of 240°C), good flame retardancy: high flame retardancy without the use of flame retardant additives, excellent electrical insulation performance: high dielectric strength, stable dielectric properties, radiation resistance, hydrolysis resistance and wide chemical resistance under various clock temperatures, frequencies and temperature conditions: insoluble in all common solvents - excellent acid and alkali resistance, lubricating oil resistance, excellent barrier properties and low moisture absorption properties; a 150°C low-smoke and halogen-free flame retardant modified irradiated EPDM insulation layer 3 is extruded between the first polyetheretherketone film sheath and the second polyetheretherketone film sheath, and a Twaron aramid fiber braided reinforcement layer 5 is woven outside the second polyetheretherketone film sheath, which has high strength (excellent Strength-to-weight ratio characteristics), high modulus, high dimensional stability, excellent heat resistance, chemical corrosion resistance, no melting point (degradation only occurs when the temperature reaches 500°C), non-flammable; the polyimide film wrapping layer 6 is wrapped around the Twaron aramid fiber braided reinforcement layer 5, so that the cable has excellent high temperature resistance, radiation resistance, chemical corrosion resistance and mechanical properties. It can be used for a long time in the air at 250-280°C, and polyimide can prevent combustion without adding flame retardants; in the polyimide film The outer surface of the sheath is coated with ZS-322 transparent high-temperature resistant heat-insulating and thermal insulation coating, which is dried to form a high-temperature resistant heat-insulating and thermal insulation coating layer 7, which increases the temperature resistance of the cable by more than 10%, can withstand open flame roasting, and has a fire retardant grade of A. It is acid and alkali resistant, has good antioxidant properties, and has good adhesion. A high-toughness, heat-resistant, and wear-resistant polyvinylidene fluoride outer sheath 8 is extruded outside the high-temperature resistant heat-insulating and thermal insulation coating layer, so that the cable has excellent heat resistance, strongest toughness, low friction coefficient, strong corrosion resistance, aging resistance, weather resistance, and good radiation resistance.

[0074] Embodiment 2:

[0075] A method for preparing a high temperature resistant and bending resistant ethylene propylene rubber insulated cable for rail transit, comprising the following steps:

[0076] 1) Preparation of conductor:

[0077] 1-1) Wire drawing: First, a copper rod with a diameter of 3mm is drawn into a copper wire with a diameter of 0.99mm on a LT2-15 / 350 copper wire drawing machine. The sizes of the wire drawing dies are: 2.76, 2.55, 2.35, 2.16, 1.99, 1.83, 1.69, 1.56, 1.43, 1.32, 1.02mm; the copper wire outlet speed is 10-20m / s, and the maximum annealing voltage is The current is 1200A; then the copper wire with a diameter of 0.99mm is drawn into a copper wire with a diameter of 0.3-0.5mm on the LHT-200 / 17 copper small drawing machine wire. The sizes of the wire drawing dies can be: 0.83, 0.74, 0.65, 0.59, 0.52, 0.46, 0.40, 0.35, 0.31mm, the copper wire emergence speed is 8-16m / s, and the maximum annealing current is 600A;

[0078] 1-2) Wire bundling: 23 to 63 copper wires with a diameter of 0.3 to 0.5 mm are bundled into strands by a DF-GJ / 500 type wire bundling machine, the bundle pitch ratio range is 20 to 30, the bundle outer diameter is 1.15 to 3.26 mm, the gear shift range is Z1: 33 to 50, Z2: 30 to 47, and the bundle speed is 5 to 45 m / min;

[0079] 1-3) Strand re-twisting: The 7 to 61 strands of wire are re-twisted on a LLY500 / 30 cage stranding machine in a 1+6+12+18+24 arrangement to form a soft copper conductor of the sixth category structure in accordance with the standard GB / T3956-2008. The re-twisted outer diameter is 3.4 to 29.6 mm. When the structure is 1+6+12, the ratio of the second and third layer diameters is set to be no more than 25 and 14; when the structure is 1+6+12+18, the ratio of the second, third, and fourth layer diameters is set to be no more than 25, 20, and 14;

[0080] 2) The first polyetheretherketone film wrapping process: directly wrap the polyetheretherketone film with a thickness of 0.1-0.2mm and a width of 35-55mm on the outside of the conductor through an LLY500 / 30 type cage stranding machine, and then wind it up on the coil, using a single-layer overlapping wrapping method, with the overlap rate controlled at 15-30%, and the wrapping angle at 15-45°. The outer diameter of the cable core after wrapping is calculated according to the formula "outer diameter before wrapping + number of layers × 3 × wrapping tape thickness", and is controlled at 3.7-30.2mm;

[0081] 3) 150℃ low-smoke halogen-free flame-retardant modified irradiated EPDM rubber insulation layer extrusion process: The cable conductor wrapped with polyetheretherketone film is extruded through SJ-45 / 25~120 / 25 type extruder to complete the 150℃ low-smoke halogen-free flame-retardant modified irradiated EPDM rubber insulation layer and obtain the insulated wire core. The heating temperature of the extruder barrel in the first to sixth zones is 100±5℃, 110±5℃, 115±5℃, 125±5℃, 135±5℃, 140±5℃ respectively; the head flange heating temperature is 145±5℃; the mold heating temperature in the first to third zones is 155±5℃, 165±5℃, 175 ±5℃; 150℃ low smoke halogen-free flame retardant modified irradiated EPDM insulation material is melted to molten state and filtered through two layers of filter screens with 60 mesh and 120 mesh; the mold adopts an extrusion tube mold, which can make full use of the stretchability of the modified EPDM insulation material to improve the extrusion quality. The mold core matching range is 5-35mm, and the mold sleeve matching range is 10-45mm; the nominal insulation thickness is 0.7-2.0mm, and the thinnest point is not less than 90%-0.1mm of the nominal value according to the formula, and is controlled at 0.53-1.7mm; the outer diameter of the insulation core ranges from 5.5 to 34.5mm; the traction speed is controlled at 20-80m / min;

[0082] 3-1) The surface of the extruded insulated wire core should be smooth without pores and impurities and be water-cooled in a 25-meter-long constant temperature water tank. After the insulated wire core exits the water tank, it is dried with a hot air drying device, and then passes a 10-25kV spark test as an intermediate inspection. It is then pulled to the cable drum to complete the 150°C low-smoke, halogen-free, flame-retardant, modified irradiated ethylene-propylene rubber insulation layer extrusion process;

[0083] 3-2) Winding the insulated wire core on the inner traction in a racetrack winding manner, and completing electron beam irradiation through a CELV-8 electron accelerator in a circular irradiation process to obtain an irradiated insulated wire core; the accelerator energy range is 1.0 to 2.5 MeV, the beam current range is 10 to 60 mA, and the power range is 60 to 100 kW;

[0084] 4) Wrapping process of the second polyetheretherketone film: Wrap the insulated wire core with a polyetheretherketone film with a thickness of 0.1-0.2 mm and a width of 35-55 mm on a JLC-500 / 1+12 type fork twisting machine or a CLY-1250 / 1+6 type cabling machine, using a double-layer gap wrapping mode, the first layer gap type is left-handed, the second layer gap type is right-handed, the gap rate is 2-5%, the wrapping angle is 15-45°, and the outer diameter after wrapping is calculated according to the formula "outer diameter before wrapping + number of layers × 2 × wrapping tape thickness", and is controlled within 5.9-35.3 mm;

[0085] 5) Weaving process of Twaron aramid fiber braided reinforcement layer: twist 4 to 9 Twaron aramid fiber strands with a diameter of 0.1 to 0.2 mm into strands, and then weave the strands on a HGSB-16 spindle braiding machine or a GSB-1A / 24 spindle braiding machine to form a Twaron aramid fiber braided reinforcement layer. The braided reinforcement layer is not allowed to be welded as a whole, the braiding should be uniform, the surface broken wires should be trimmed, and the fiber spindles should not be replaced more than once per meter length; the braiding density is controlled at 75 to 85%, the pitch is 10 to 40 mm, the braiding angle is 15 to 45°, and the outer diameter of the cable core after braiding is calculated according to the formula "outer diameter before braiding + 4×fiber monofilament diameter" and is controlled at 6.3 to 36.1 mm;

[0086] 6) Wrapping process of polyimide film: After the Twaron aramid fiber filament braided reinforcement layer, directly wrap the polyimide film with a thickness of 0.04-0.08 mm and a width of 35-60 mm, using a single-layer overlapping wrapping mode, with the overlap rate controlled at 20-35%, and the outer diameter after wrapping is calculated according to the formula "outer diameter before wrapping + number of layers × 3 × wrapping tape thickness", and is controlled at 6.5-36.4 mm;

[0087] 7) Process of ZS-322 transparent high temperature resistant heat insulation coating: The cable core wrapped with polyimide film is passed through the 360° automatic spraying equipment horizontally and slowly at a uniform speed. A hot air drying device is placed in front of the equipment to clean the dust, grease, moisture and other impurities on the surface of the cable core to ensure balanced coating. The overall spraying thickness is 100-150μm;

[0088] 7-1) After spraying, the cable enters the drying device, the drying temperature is 60-70℃, the oven length is 2 meters, and the drying speed is 2m / min, so that the cable can stay in the drying device for 1 minute to ensure that the coating is dry and no impurities adhere to it;

[0089] 7-2) After coating, the cable core will be sent to a constant temperature drying room at 50°C and placed for 24 hours;

[0090] 8) Extrusion process of high-toughness, heat-resistant and wear-resistant polyvinylidene fluoride outer sheath: After drying, the cable core is extruded through a SJ-90 / 25~150 / 25 extruder to complete the extrusion of the high-toughness, heat-resistant and wear-resistant polyvinylidene fluoride outer sheath, wherein the heating temperatures of the extruder barrel in the first to sixth zones are 180±5℃, 180±5℃, 185±5℃, 190±5℃, 195±5℃, 200±5℃ respectively; the heating temperature of the head flange is 205±5℃; the heating temperature of the mold in the first to third zones is 205±5℃, 210±5℃, 215±5℃ respectively; The olefin sheath material needs to be filtered through three layers of 40 mesh, 60 mesh and 100 mesh when it is melted to a molten state; the screw speed is 30-40r / min, and the extrusion speed is controlled at 10-30m / min; the mold core matching range is 10-40mm, and the mold sleeve matching range is 20-50mm; the nominal thickness of the sheath should be calculated according to the formula "0.035× cable core outer diameter before extrusion + 1.0mm", and controlled at 1.4-3.0mm, and the thinnest point should be no less than 80%-0.2mm of the nominal value according to the formula, and controlled at 0.92-2.2mm; the cable outer diameter range is 9.5-43mm;

[0091] 8-1) The surface of the extruded cable should be smooth without pores and impurities and be cooled by water in a 25-meter-long constant temperature water tank. After the cable comes out of the water tank, it should be dried by a hot air drying device and then pass a 15-25kV spark test as an intermediate inspection;

[0092] 8-3) Finally, the product logo is sprayed on the surface of the cable outer sheath by a printer, and then the finished cable is pulled onto the cable drum by a crawler tractor to complete the outer sheath extrusion process.

[0093] The present invention improves the structure of Example 1 and the preparation method of Example 2, and the properties of the cable prepared are as follows:

[0094]

[0095] Embodiment 3:

[0096] A 150°C low-smoke halogen-free flame-retardant modified irradiated ethylene-propylene rubber insulation material, comprising the following components in parts by mass:

[0097] EPDM rubber: 45 parts, ultrafine polyimide resin powder: 18 parts, dioctyl phthalate: 5 parts, graphene: 1 part, white oil: 3 parts, maleic anhydride: 1 part, trimethylolpropane trimethacrylate: 1 part, magnesium hydroxide inorganic flame retardant: 5 parts, RCA aluminate coupling agent: 0.1 parts, antioxidant and anti-copper agent 1024: 0.3 parts, zinc stearate: 0.5 parts.

[0098] Embodiment 4:

[0099] A 150°C low-smoke halogen-free flame-retardant modified irradiated ethylene-propylene rubber insulation material, comprising the following components in parts by mass:

[0100] EPDM rubber: 50 parts, ultrafine polyimide resin powder: 21.5 parts, dioctyl phthalate: 7.5 parts, graphene: 3 parts, white oil: 5.5 parts, maleic anhydride: 1.5 parts, trimethylolpropane trimethacrylate: 2 parts, magnesium hydroxide inorganic flame retardant: 7.5 parts, RCA aluminate coupling agent: 0.3 parts, antioxidant and anti-copper agent 1024: 0.55 parts,

[0101]

[0102]

[0103] Zinc stearate: 0.75 parts.

[0104] Embodiment 5:

[0105] A 150°C low-smoke halogen-free flame-retardant modified irradiated ethylene-propylene rubber insulation material, comprising the following components in parts by mass:

[0106] EPDM rubber: 55 parts, ultrafine polyimide resin powder: 25 parts, dioctyl phthalate: 10 parts, graphene: 5 parts, white oil: 8 parts, maleic anhydride: 2 parts, trimethylolpropane trimethacrylate: 3 parts, magnesium hydroxide inorganic flame retardant: 10 parts, RCA aluminate coupling agent: 0.5 parts, antioxidant and anti-copper agent 1024: 0.8 parts, zinc stearate: 1 part.

[0107] Embodiment 6:

[0108] A 150°C low-smoke halogen-free flame-retardant modified irradiated ethylene-propylene rubber insulation material, comprising the following components in parts by mass:

[0109] EPDM rubber: 53 parts, ultrafine polyimide resin powder: 22 parts, dioctyl phthalate: 8 parts, graphene: 4 parts, white oil: 6 parts, maleic anhydride: 2 parts, trimethylolpropane trimethacrylate: 2 parts, magnesium hydroxide inorganic flame retardant: 8 parts, RCA aluminate coupling agent: 0.4 parts, antioxidant and anti-copper agent 1024: 0.7 parts, zinc stearate: 0.9 parts.

[0110] The performance indicators of the insulating materials prepared by the components of Examples 3-6 are shown in the following table:

[0111] Recombination Figure 2-5 Electron microscopy images were compared. Figure 2 The figure shows the insulating material without graphene. It can be seen from the figure that the insulating material has poor color and gloss, and the insulating material has poor thermal stability and mechanical properties under high temperature environment. Figure 3-5The figure shows the insulating material with graphene added and white oil added, so that the graphene can be evenly dispersed in the insulating material, making the insulating material have better thermal stability. Figure 2 In comparison, the color and gloss are obviously better than before adding graphene, which can keep the mechanical properties of the insulation material stable in high temperature environment; if it is not combined with white oil, the graphene added alone cannot be evenly dispersed in the insulation material, which will make the later insulation material in a high temperature environment. The mechanical properties are unstable, the color is poor, and it is easy to crack;

[0112] As an indispensable transmission link in the electrical system of rail vehicles, the requirements for cable reliability and durability are becoming higher and higher under the trend of accelerating technological updates in rail transit. Compared with polyolefins, TPV, TPE, TPU and other materials, the EPDM rubber of the present invention has better electrical insulation performance, weather resistance, high temperature resistance and ozone resistance, and is also soft and resistant to bending. It is one of the ideal materials for cable insulation and is suitable for use in rail transit traction systems.

[0113] The present invention has many specific application paths. The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements can be made without departing from the principle of the present invention. These improvements should also be regarded as the protection scope of the present invention.

Claims

1. A high temperature resistant and bending resistant ethylene propylene rubber insulated cable for rail transit, comprising a conductor, characterized in that: The conductor is wrapped with a first polyetheretherketone film wrapping layer and a second polyetheretherketone film wrapping layer in sequence, a 150°C low-smoke halogen-free flame-retardant modified irradiated ethylene-propylene rubber insulation layer is extruded between the first polyetheretherketone film wrapping layer and the second polyetheretherketone film wrapping layer, a polyimide film wrapping layer is wrapped after a Twaron aramid fiber braided reinforcement layer is woven outside the second polyetheretherketone film wrapping layer, a ZS-322 transparent high-temperature resistant heat-insulating coating is coated on the outer surface of the polyimide film wrapping layer and dried to form a high-temperature resistant heat-insulating coating layer, and a high-toughness, heat-resistant and wear-resistant polyvinylidene fluoride outer sheath is extruded outside the high-temperature resistant heat-insulating coating layer; wherein: the 150°C low-smoke halogen-free flame-retardant modified irradiated ethylene-propylene rubber insulation material includes the following components in parts by mass: EPDM rubber: 45-55 parts Ultrafine polyimide resin powder: 18-25 parts Plasticizer: 5-10 parts Graphene: 1-5 parts White oil: 3-8 parts Maleic anhydride: 1-2 parts Cross-linking agent: 1-3 parts Magnesium hydroxide inorganic flame retardant: 5-10 parts Surface treatment agent: 0.1-0.5 parts Antioxidant and anti-copper agent 1024: 0.3-0.8 parts Lubricant: 0.5-1 part.

2. The high temperature and bending resistant EPDM insulated cable for rail transit according to claim 1, characterized in that: The conductor is a Category 6 soft copper conductor.

3. The 150°C low-smoke halogen-free flame-retardant modified irradiated ethylene-propylene rubber insulation material according to claim 2, characterized in that: The plasticizer is dioctyl phthalate.

4. The 150°C low-smoke halogen-free flame-retardant modified irradiated ethylene-propylene rubber insulation material according to claim 3, characterized in that: The cross-linking auxiliary agent is trimethylolpropane trimethacrylate.

5. The 150°C low-smoke halogen-free flame-retardant modified irradiated ethylene-propylene rubber insulation material according to claim 4, characterized in that: The surface treatment agent is RCA aluminate coupling agent.

6. The 150°C low-smoke halogen-free flame-retardant modified irradiated ethylene-propylene rubber insulation material according to claim 5, characterized in that: The lubricant is zinc stearate.

7. A method for preparing a high temperature resistant and bending resistant EPDM insulated cable for rail transit as claimed in any one of claims 1 to 6, characterized in that: The following steps are involved: 1) Preparation of conductor: 1-1) Wire drawing: First, a copper rod with a diameter of 3mm is drawn into a copper wire with a diameter of 0.99mm on a LT2-15 / 350 copper wire drawing machine. The sizes of the wire drawing dies are: 2.76, 2.55, 2.35, 2.16, 1.99, 1.83, 1.69, 1.56, 1.43, 1.32, 1.02mm; the copper wire outlet speed is 10-20m / s, and the maximum annealing voltage is 2.5V. The current is 1200A; then the copper wire with a diameter of 0.99mm is drawn into a copper wire with a diameter of 0.3-0.5mm on the LHT-200 / 17 copper small drawing machine wire. The sizes of the wire drawing dies can be: 0.83, 0.74, 0.65, 0.59, 0.52, 0.46, 0.40, 0.35, 0.31mm, the copper wire emergence speed is 8-16m / s, and the maximum annealing current is 600A; 1-2) Wire bundling: 23 to 63 copper wires with a diameter of 0.3 to 0.5 mm are bundled into strands by a DF-GJ / 500 type wire bundling machine, the bundle pitch ratio range is 20 to 30, the bundle outer diameter is 1.15 to 3.26 mm, the gear shift range is Z1: 33 to 50, Z2: 30 to 47, and the bundle speed is 5 to 45 m / min; 1-3) Strand re-twisting: The 7 to 61 strands of wire are re-twisted on the LLY500 / 30 cage stranding machine in the arrangement of 1+6+12+18+24 to form a soft copper conductor of the sixth category structure in accordance with the standard GB / T3956-2008. The outer diameter of the re-twisted wire is 3.4 to 29.6 mm. When the structure is 1+6+12, the ratio of the second and third layer diameters is set to be no more than 25 and 14; when the structure is 1+6+12+18, the ratio of the second, third and fourth layer diameters is set to be no more than 25, 20 and 14; 2) The first polyetheretherketone film wrapping process: directly wrap the polyetheretherketone film with a thickness of 0.1-0.2mm and a width of 35-55mm on the outside of the conductor through the LLY500 / 30 cage stranding machine, and then wind it up on the coil. Use a single-layer overlapping wrapping method, the overlap rate is controlled at 15-30%, the wrapping angle is 15-45°, and the outer diameter of the cable core after wrapping is calculated according to the formula "outer diameter before wrapping + number of layers × 3 × wrapping tape thickness", which is controlled at 3.7-30.2mm; 3) 150℃ low-smoke halogen-free flame-retardant modified irradiated EPDM rubber insulation layer extrusion process: The cable conductor wrapped with polyetheretherketone film is extruded through SJ-45 / 25~120 / 25 extruder to complete the 150℃ low-smoke halogen-free flame-retardant modified irradiated EPDM rubber insulation layer and obtain the insulated wire core. The heating temperature of the extruder barrel in the first to sixth zones is 100±5℃, 110±5℃, 115±5℃, 125±5℃, 135±5℃, 140±5℃ respectively; the head flange heating temperature is 145±5℃; the mold heating temperature in the first to third zones is 155±5℃, 165±5℃, 175 ±5℃; 150℃ low smoke halogen-free flame retardant modified irradiated EPDM insulation material is melted to molten state and filtered through two layers of filter screens with 60 mesh and 120 mesh; the mold adopts an extrusion tube mold, which can make full use of the stretchability of the modified EPDM insulation material to improve the extrusion quality. The mold core matching range is 5-35mm, and the mold sleeve matching range is 10-45mm; the nominal insulation thickness is 0.7-2.0mm, and the thinnest point is not less than 90%-0.1mm of the nominal value according to the formula, and is controlled at 0.53-1.7mm; the outer diameter of the insulation core ranges from 5.5 to 34.5mm; the traction speed is controlled at 20-80m / min; 3-1) The surface of the extruded insulated wire core should be smooth without pores and impurities and be cooled by water in a 25-meter-long constant temperature water tank. After the insulated wire core comes out of the water tank, it should be dried by a hot air drying device, and then pass a 10-25kV spark test as an intermediate inspection. Then, it is pulled to the cable drum to complete the 150℃ low-smoke halogen-free flame-retardant modified irradiated ethylene-propylene rubber insulation layer extrusion process; 3-2) Winding the insulated wire core on the inner traction in a racetrack winding manner, and completing electron beam irradiation through a CELV-8 electron accelerator in a circular irradiation process to obtain an irradiated insulated wire core; the accelerator energy range is 1.0 to 2.5 MeV, the beam current range is 10 to 60 mA, and the power range is 60 to 100 kW; 4) Wrapping process of the second polyetheretherketone film: Wrap the insulated wire core with a polyetheretherketone film with a thickness of 0.1-0.2mm and a width of 35-55mm on a JLC-500 / 1+12 fork twisting machine or a CLY-1250 / 1+6 cabling machine, using a double-layer gap wrapping mode, with the first layer of gap type left-handed and the second layer of gap type right-handed, with a gap rate of 2-5%, a wrapping angle of 15-45°, and the outer diameter after wrapping is calculated according to the formula "outer diameter before wrapping + number of layers × 2 × wrapping tape thickness", and controlled within 5.9-35.3mm; 5) Weaving process of Twaron aramid fiber braided reinforcement layer: twist 4 to 9 Twaron aramid fiber strands with a diameter of 0.1 to 0.2 mm into strands, and then weave the strands on a HGSB-16 spindle braiding machine or a GSB-1A / 24 spindle braiding machine to form a Twaron aramid fiber braided reinforcement layer. The braided reinforcement layer is not allowed to be welded as a whole, the braiding should be uniform, the surface broken wires should be trimmed, and the fiber spindles should not be replaced more than once per meter length; the braiding density is controlled at 75-85%, the pitch is 10-40 mm, the braiding angle is 15-45°, and the outer diameter of the cable core after braiding is calculated according to the formula "outer diameter before braiding + 4×fiber monofilament diameter", and is controlled at 6.3-36.1 mm; 6) Wrapping process of polyimide film: After the Twaron aramid fiber woven reinforcement layer is directly wrapped with a polyimide film with a thickness of 0.04-0.08mm and a width of 35-60mm, a single-layer overlapping wrapping mode is adopted, and the overlap rate is controlled at 20-35%. The reference outer diameter after wrapping is calculated according to the formula "outer diameter before wrapping + number of layers × 3 × wrapping tape thickness", and is controlled at 6.5-36.4mm; 7) Process of ZS-322 transparent high temperature resistant heat insulation coating: The cable core wrapped with polyimide film is passed through the 360° automatic spraying equipment horizontally and slowly at a uniform speed. A hot air drying device is placed in front of the equipment to clean the dust, grease, moisture and other impurities on the surface of the cable core to ensure balanced coating. The overall spraying thickness is 100-150μm; 7-1) After spraying, the cable enters the drying device, the drying temperature is 60-70℃, the oven length is 2 meters, and the drying speed is 2m / min, so that the cable can stay in the drying device for 1 minute to ensure that the coating is dry and no impurities adhere to it; 7-2) After coating, the cable core will be sent to a constant temperature drying room at 50°C and placed for 24 hours; 8) Extrusion process of high-toughness, heat-resistant and wear-resistant polyvinylidene fluoride outer sheath: After drying, the cable core is extruded through a SJ-90 / 25~150 / 25 extruder to complete the extrusion of the high-toughness, heat-resistant and wear-resistant polyvinylidene fluoride outer sheath. The heating temperatures of the extruder barrel in the first to sixth zones are 180±5℃, 180±5℃, 185±5℃, 190±5℃, 195±5℃, 200±5℃ respectively; the heating temperature of the head flange is 205±5℃; the heating temperature of the mold in the first to third zones is 205±5℃, 210±5℃, 215±5℃ respectively; The olefin sheath material needs to be filtered through three layers of 40 mesh, 60 mesh and 100 mesh when it is melted to a molten state; the screw speed is 30-40r / min, and the extrusion speed is controlled at 10-30m / min; the mold core matching range is 10-40mm, and the mold sleeve matching range is 20-50mm; the nominal thickness of the sheath should be calculated according to the formula "0.035× cable core outer diameter before extrusion + 1.0mm", and controlled at 1.4-3.0mm, and the thinnest point should not be less than 80%-0.2mm of the nominal value according to the formula, and controlled at 0.92-2.2mm; the cable outer diameter range is 9.5-43mm; 8-1) The surface of the extruded cable should be smooth without pores and impurities and be cooled by water in a 25-meter-long constant temperature water tank. After the cable comes out of the water tank, it should be dried by a hot air drying device and then pass a 15-25kV spark test as an intermediate inspection; 8-3) Finally, the product logo is sprayed on the surface of the cable outer sheath by a printer, and then the finished cable is pulled onto the cable drum by a crawler tractor to complete the outer sheath extrusion process.

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