A double-core cable for a photovoltaic power generation system and a method for manufacturing the same

Abstract

The present application relates to the technical field of cable, especially to a double-core cable for photovoltaic power generation system and a preparation method thereof.The double-core cable comprises a tie, a sheath layer and two cable cores, each of the cable cores is wrapped with a sheath layer, the two sheath layers are integrally connected with the tie, the sheath layer and the tie are made of weather-resistant and anti-fracture sheath material, the weather-resistant and anti-fracture sheath material comprises the following components in parts by weight: EVA masterbatch 70-88 parts, HDPE resin 20-36 parts, PVB resin 15-25 parts, toughening fiber 5-10 parts, nano carbon black 25-45 parts, epoxy soybean oil 3-7 parts and processing aid 5-30 parts.The double-core cable of the present application is not prone to fracture after exposure or low-temperature freezing, and has better performance.

Description

Technical Field

[0001] This invention relates to the technical field of cables, and in particular to a dual-core cable for photovoltaic power generation systems and its manufacturing method. Background Technology

[0002] Photovoltaic power generation is a technology that directly converts light energy into electrical energy using the photovoltaic effect at semiconductor interfaces. China is one of the countries with the fastest growth in photovoltaic power generation installations globally. Photovoltaic power generation systems require cables to transmit electricity. Because photovoltaic power generation systems need to be installed outdoors in direct sunlight, the cables used in these systems must withstand exposure to intense sunlight and extremely low outdoor temperatures.

[0003] In related technologies, a dual-core cable is disclosed, comprising a connecting rib and two cable cores. Each cable core includes a conductor, an insulation layer, and a sheath layer arranged sequentially from the inside out, with the connecting rib connecting the two sheath layers. Each cable core of the dual-core cable has the same structure, mechanical properties, electrical properties, and environmental resistance as a single-core cable. The price of a dual-core cable is twice that of a single-core cable; the price increase is not due to the addition of the connecting rib, as the material cost of the connecting rib is borne by the manufacturer. The installation workload of a dual-core cable is less than that of a single-core cable, about half that of a single-core cable, making laying quick and convenient and reducing construction time. Dual-core cables do not require bundling, reducing construction costs and time. Because there are no gaps between the cables, the appearance is aesthetically pleasing. Therefore, it has gained widespread acceptance.

[0004] Regarding the aforementioned technology, the inventors believe that the contact area at the connection between the reinforcing rib and the sheath layer is small, and multiple bends occur during production, storage, transportation, and installation, making the surface prone to creases or cracks. After exposure to sunlight or freezing at low temperatures, the connection between the reinforcing rib and the sheath layer is prone to breakage. Summary of the Invention

[0005] To address the issue of twin-core cables used in photovoltaic power generation systems being prone to breakage after exposure to sunlight or freezing temperatures, this application provides a twin-core cable for photovoltaic power generation systems and its manufacturing method.

[0006] This application provides a dual-core cable for a photovoltaic power generation system, employing the following technical solution: A dual-core cable for a photovoltaic power generation system includes a connecting rod, a sheath layer, and two cable cores. Each cable core is wrapped with a sheath layer, and both sheath layers are integrally connected to the connecting rod. Both the sheath layer and the connecting rod are made of weather-resistant and fracture-resistant sheath material, which comprises the following components in parts by weight: 70-88 parts of EVA masterbatch, 20-36 parts of HDPE resin, 15-25 parts of PVB resin, 5-10 parts of toughening fiber, 25-45 parts of nano carbon black, 3-7 parts of epoxidized soybean oil, and 5-30 parts of processing aids.

[0007] By adopting the above technical solution, EVA masterbatch can be used as a raw material for cable sheathing materials applied outdoors. This application also uses HDPE resin, PVB resin, toughening fiber, nano carbon black and epoxidized soybean oil. Through experiments, this application found that when the above raw material ratio is used, EVA masterbatch, HDPE resin and PVB resin can form a weather-resistant and fracture-resistant sheathing material. It not only has excellent heat resistance and cold resistance, but also excellent light aging resistance, oil resistance and solvent resistance. It also has excellent fracture resistance and electrical insulation. Therefore, the sheathing layer and connecting ribs with an integral molding structure made of the above sheathing material are not easy to break after exposure to the sun and low temperature freezing. It also has good flexibility, aging resistance, oil resistance and solvent resistance. After being subjected to multiple bends or aging by oil and solvents, it is not easy to crack. It can adapt to the working environment of photovoltaic power generation system and extend the service life of dual-core cable.

[0008] The improved performance of the weather-resistant and fracture-resistant sheathing material prepared using the above-mentioned raw material ratio may be due to the following reasons: the crystallinity of HDPE resin is 80%-90%, the molecular weight range is 40,000-300,000, and the softening temperature is 125-135℃; the relative density of PVB resin is 1.08-1.10, the molecular weight range is 30k-45k, and the softening temperature is 60-65℃; the toughening fibers dispersed in the sheathing material can act as bridges, connecting the sheathing materials and enhancing their toughness; and the nano carbon black can not only improve the wear resistance of the sheathing material, but also improve its high-temperature resistance and light aging resistance. Therefore, by blending EVA masterbatch, HDPE resin, PVB resin, toughening fiber, and nano carbon black in the above proportions, a sheathing material with high softening temperature, good toughness, and excellent heat resistance, cold resistance, and light aging resistance can be obtained. At the same time, epoxidized soybean oil has a plasticizing effect and helps to improve the solvent resistance of the sheathing material. Processing aids give the sheathing material good processing performance, which can be smoothly processed into an integrally molded sheathing layer and connecting ribs. The integrally molded structure further enhances the toughness at the connection between the connecting ribs and the sheathing layer, thus helping to reduce the breakage at the connection between the connecting ribs and the sheathing layer.

[0009] In one specific implementation, the toughening fiber is an aramid fiber.

[0010] By adopting the above technical solutions, aramid fibers possess excellent properties such as ultra-high strength, high modulus, high temperature resistance, and flame retardancy. Using aramid fibers not only enhances the toughness of the sheath material, but also prevents cracks from expanding or prolonging when cracks occur at the connection between the sheath layer and the connecting reinforcement, thus preventing breakage of the sheath layer and the connecting reinforcement. Furthermore, aramid fibers can further enhance the heat resistance and flame retardant properties of the sheath layer, thereby extending the service life of the dual-core cable.

[0011] In one specific implementation, the processing aid includes a silane coupling agent.

[0012] By adopting the above technical solutions, the dispersibility of aramid fibers in the sheath material and their adhesion to other components have a significant impact on the effectiveness of the aramid fibers. Pre-treating aramid fibers with silane coupling agents can improve their dispersibility in the sheath material and enhance their adhesion to components such as EVA masterbatch, HDPE resin, and PVB resin, thereby further strengthening the toughness, heat resistance, and flame retardant properties of the sheath material.

[0013] In one specific implementation, the processing aid includes at least one of talc, heavy calcium carbonate, and nano-titanium dioxide.

[0014] By adopting the above technical solutions, talc, heavy calcium carbonate, and nano-titanium dioxide can all play roles in filling, cost reduction, reinforcement, and weather resistance in the sheathing material. Furthermore, talc possesses lubricating, anti-sticking, flow-aiding, fire-resistant, insulating, and flexible properties, which help improve the processing performance, flame retardant properties, and insulation performance of the sheathing material. Heavy calcium carbonate adsorbs ions in the sheathing material, reducing the free ionization of conductive ions and improving the insulation performance, heat and oxygen aging resistance, and mechanical properties of the sheathing material. Nano-titanium dioxide can both reflect and scatter ultraviolet rays, and also absorb ultraviolet rays, exhibiting stronger UV blocking capabilities, which helps reduce the damage to dual-core cables caused by sunlight exposure.

[0015] In one specific implementation, the processing aid includes a composite flame retardant comprising aluminum hydroxide, ammonium octamolate, antimony trioxide, and zinc stannate in a weight ratio of (40-50):(10-15):(8-12):(23-33).

[0016] By adopting the above technical solutions, different flame retardants can be used in combination to achieve effects beyond those of a single flame retardant. However, the type and ratio of flame retardants need to be adjusted according to the other components contained in the sheath material; otherwise, the flame retardant effect of the sheath material will decrease. This application has found through experiments that when using the above-mentioned component ratio of the sheath material, controlling the component ratio of the composite flame retardant within the above-mentioned range can result in a sheath material with significantly improved flame retardant effect, which helps to improve the safety of dual-core cables.

[0017] In one specific implementation, the processing aid includes a lubricant, which is at least one of petrolatum or stearic acid.

[0018] By adopting the above technical solutions, both petrolatum and stearic acid possess excellent lubricity, which helps improve the processing performance of the sheathing material and facilitates its fabrication into a structure where two sheathing layers are integrally connected to a reinforcing rib. Furthermore, stearic acid helps prevent "charring" of the sheathing material during processing, while petrolatum can improve its insulation properties.

[0019] In one specific implementation, the HDPE resin is an HDPE resin with the designation H112PC or an HDPE resin with the designation HE1105.

[0020] By adopting the above technical solutions, HDPE resin with grade H112PC or HDPE resin with grade HE1105 both have excellent wear resistance, electrical insulation, toughness and cold resistance, which helps to further reduce the breakage of dual-core cables.

[0021] Secondly, this application provides a method for manufacturing a dual-core cable for a photovoltaic power generation system, employing the following technical solution: A method for manufacturing a two-core cable for a photovoltaic power generation system comprises the following steps: Cable core manufacturing: An insulating layer is wrapped around the outer peripheral wall of a conductor to obtain the cable core; Preparation of weather-resistant and fracture-resistant sheath material: EVA masterbatch, HDPE resin, PVB resin and nano carbon black are mixed according to the formula to obtain mixture A. Toughening fiber, epoxidized soybean oil and processing aids are mixed to obtain mixture B. Mixture A is heated to 110-115℃ and mixed at a constant temperature for 10-15 minutes. Then mixture B is added and mixed at a constant temperature for 5-8 minutes. Then the temperature is lowered to 40-45℃ to obtain the total mixture. The total mixture is extruded and granulated to obtain the weather-resistant and fracture-resistant sheath material. Manufacturing a two-core cable: The weather-resistant and fracture-resistant sheath material is continuously extruded and formed, and the weather-resistant and fracture-resistant sheath material is wrapped around the two cable cores to form a structure in which the two sheath layers are integrally connected with the same connecting rib. After natural cooling, a two-core cable is obtained.

[0022] By adopting the above technical solutions and methods, the components of the cable can be more evenly dispersed, improving the material uniformity of the sheath material and further enhancing the fracture resistance of the dual-core cable.

[0023] In summary, this application includes at least one of the following beneficial technical effects: 1. This application helps to simultaneously improve the heat resistance, cold resistance and mechanical properties of dual-core cables, and reduce the breakage of dual-core cables after exposure to sunlight and low-temperature freezing; 2. The use of aramid fiber in this application helps to enhance the toughness of the sheath material, prevent cracks from expanding or extending, prevent the sheath layer from breaking with the reinforcing ribs, and further enhance the heat resistance and flame retardant properties of the sheath layer, thereby extending the service life of the dual-core cable; 3. The use of silane coupling agent in this application can improve the dispersibility of aramid fiber in the sheath material and enhance the adhesion effect of aramid fiber with components such as EVA masterbatch, HDPE resin, and PVB resin. Detailed Implementation

[0024] The present application will be further described in detail below with reference to embodiments and comparative examples. Example

[0025] Example 1 This embodiment provides a dual-core cable, including a connecting rib, a sheath layer, and two cable cores. Each cable core includes a conductor and an insulation layer arranged sequentially from the inside out. Each cable core's insulation layer is wrapped with a sheath layer. The connecting rib is located between the two sheath layers. The length direction of the connecting rib is the same as the circumferential direction of the sheath layer. Both sheath layers are integrally connected to the connecting rib. Both the sheath layer and the connecting rib are made of weather-resistant and fracture-resistant sheath material.

[0026] The weather-resistant and fracture-resistant sheath material consists of the following components: 79 kg of EVA masterbatch (Arkema, grade 28-25), 28 kg of HDPE resin (grade H112PC), 20 kg of PVB resin (MowitalPVBB20H), 7 kg of aramid fiber (Yaobang, 1-3 mm), 35 kg of nano carbon black, 5 kg of epoxidized soybean oil, 1.5 kg of silane coupling agent (KH-560), 10.5 kg of talc, 2 kg of petrolatum, 1 kg of stearic acid, and 15 kg of composite flame retardant. The composite flame retardant is a mixture of aluminum hydroxide, ammonium octamolate, antimony trioxide, and zinc stannate in a weight ratio of 47:13:10:30.

[0027] The manufacturing method of a two-core cable is as follows: First, the cable core is made: a layer of insulating material is wrapped around the outer wall of the conductor. After the insulating material cools naturally, the insulating layer is obtained. The conductor and the insulating layer together form the cable core. Preparation of weather-resistant and fracture-resistant sheathing material: According to the above proportions, EVA masterbatch, HDPE resin, PVB resin, and nano carbon black are added to the same mixer and stirred until homogeneous to obtain mixture A. Aramid fiber, epoxidized soybean oil, and processing aids are added to the same mixer and stirred until homogeneous to obtain mixture B. Then, mixture A is added to a mixer, heated to 113℃, and stirred at a constant temperature for 13 minutes. Then, mixture B is added, and the temperature is maintained at 113℃ for 6 minutes. The material is then transferred to a cold mixer and cooled to 43℃ to obtain the final mixture. The final mixture is then transferred to a 75 / 180 two-stage granulation extruder for extrusion granulation to obtain the weather-resistant and fracture-resistant sheathing material.

[0028] Manufacturing a dual-core cable: Weather-resistant and fracture-resistant sheath material is added to a cable forming extruder and continuously extruded at a barrel temperature of 165±5℃ and a die temperature of 190℃. The weather-resistant and fracture-resistant sheath material wraps around the two cable cores and forms a structure in which the two sheath layers are integrally connected with the same connecting rib. After natural cooling, a dual-core cable is obtained.

[0029] Example 2 This embodiment provides a dual-core cable. The only difference between this embodiment and Embodiment 1 is that the weather-resistant and fracture-resistant sheath material uses the following components: 70kg of EVA masterbatch (Arkema, grade 28-25), 20kg of HDPE resin (grade H112PC), 15kg of PVB resin (MowitalPVBB20H), 5kg of aramid fiber (Yaobang, specification 1-3mm), 25kg of nano carbon black, 3kg of epoxidized soybean oil, 0.5kg of silane coupling agent (KH-560), 2.5kg of talc, 0.5kg of petrolatum, 0.5kg of stearic acid, and 6kg of composite flame retardant.

[0030] Example 3 This embodiment provides a dual-core cable. The only difference between this embodiment and Embodiment 1 is that the weather-resistant and fracture-resistant sheath material uses the following components: 88 kg of EVA masterbatch (Arkema, grade 28-25), 36 kg of HDPE resin (grade H112PC), 25 kg of PVB resin (MowitalPVBB20H), 10 kg of aramid fiber (Yaobang, specification 1-3mm), 45 kg of nano carbon black, 7 kg of epoxidized soybean oil, 2 kg of silane coupling agent (KH-560), 11 kg of talc, 2 kg of petrolatum, 2 kg of stearic acid, and 13 kg of composite flame retardant.

[0031] Example 4 This embodiment provides a dual-core cable. The only difference between this embodiment and Embodiment 1 is that an equal amount of carbon fiber (Toray, specification 1-3mm) is used to replace the aramid fiber.

[0032] Example 5 This embodiment provides a dual-core cable. The only difference between this embodiment and Embodiment 1 is that an equal amount of talc powder is used to replace the silane coupling agent.

[0033] Example 6 This embodiment provides a dual-core cable. The only difference between this embodiment and Embodiment 1 is that an equal amount of heavy calcium carbonate is used to replace talc powder.

[0034] Example 7 This embodiment provides a dual-core cable. The only difference between this embodiment and Embodiment 1 is that an equal amount of nano-titanium dioxide is used to replace talc powder.

[0035] Example 8 This embodiment provides a dual-core cable. The only difference between this embodiment and Embodiment 1 is that an equal amount of composite flame retardant is used to replace talc powder.

[0036] Example 9 This embodiment provides a dual-core cable. The only difference between this embodiment and Embodiment 1 is that an equal amount of aluminum hydroxide is used to replace the composite flame retardant.

[0037] Example 10 This embodiment provides a dual-core cable. The only difference between this embodiment and Embodiment 1 is that an equal amount of ammonium octamolate is used to replace the composite flame retardant.

[0038] Example 11 This embodiment provides a dual-core cable. The only difference between this embodiment and Embodiment 1 is that an equal amount of antimony trioxide is used to replace the composite flame retardant.

[0039] Example 12 This embodiment provides a dual-core cable. The only difference between this embodiment and Embodiment 1 is that an equal amount of zinc stannate is used to replace the composite flame retardant.

[0040] Example 13 This embodiment provides a dual-core cable. The only difference between this embodiment and Embodiment 1 is that the composite flame retardant is a mixture of aluminum hydroxide, ammonium octamolate, antimony trioxide and zinc stannate in a weight ratio of 50:10:8:32.

[0041] Example 14 This embodiment provides a dual-core cable. The only difference between this embodiment and Embodiment 1 is that the composite flame retardant is a mixture of aluminum hydroxide, ammonium octamolate, antimony trioxide and zinc stannate in a weight ratio of 40:15:12:33.

[0042] Example 15 This embodiment provides a dual-core cable. The only difference between this embodiment and Embodiment 1 is that the composite flame retardant is a mixture of aluminum hydroxide, ammonium octamolate, antimony trioxide and zinc stannate in a weight ratio of 38:17:10:35.

[0043] Example 16 This embodiment provides a dual-core cable. The only difference between this embodiment and Embodiment 1 is that the composite flame retardant is a mixture of aluminum hydroxide, ammonium octamolate, antimony trioxide and zinc stannate in a weight ratio of 52:8:16:24.

[0044] Example 17 This embodiment provides a dual-core cable. The only difference between this embodiment and Embodiment 1 is that an equal amount of talc powder is used to replace the composite flame retardant.

[0045] Example 18 This embodiment provides a dual-core cable. The only difference between this embodiment and Embodiment 1 is that talc powder is used to replace petroleum jelly and stearic acid in equal amounts.

[0046] Example 19 This embodiment provides a two-core cable. The only difference between this embodiment and Embodiment 1 is that an equal amount of HDPE resin (grade HE1105) is used to replace HDPE resin (grade H112PC).

[0047] Example 20 This embodiment provides a two-core cable. The only difference between this embodiment and Embodiment 1 is that an equal amount of HDPE resin (grade 5000S) is used to replace HDPE resin (grade H112PC).

[0048] Example 21 This embodiment provides a dual-core cable. The only difference between this embodiment and Embodiment 1 is the preparation of the weather-resistant and fracture-resistant sheath material: EVA masterbatch, HDPE resin, PVB resin, and nano-carbon black are added to the same mixer according to the above proportions and stirred until homogeneous to obtain mixture A. Aramid fiber, epoxidized soybean oil, and processing aids are added to the same mixer and stirred until homogeneous to obtain mixture B. Then, mixture A is added to a mixer, heated to 110°C, and then stirred at a constant temperature for 15 minutes. Mixture B is then added, and the temperature is maintained at 110°C for 8 minutes. The material is then introduced into a cold mixer to cool it to 40°C to obtain the final mixture. The final mixture is then introduced into a 75 / 180 two-stage granulation extruder for extrusion granulation to obtain the weather-resistant and fracture-resistant sheath material.

[0049] Example 22 This embodiment provides a dual-core cable. The only difference between this embodiment and Embodiment 1 is the preparation of the weather-resistant and fracture-resistant sheath material: EVA masterbatch, HDPE resin, PVB resin, and nano-carbon black are added to the same mixer according to the above proportions and stirred until homogeneous to obtain mixture A. Aramid fiber, epoxidized soybean oil, and processing aids are added to the same mixer and stirred until homogeneous to obtain mixture B. Then, mixture A is added to a mixer, heated to 115°C, and then stirred at a constant temperature for 10 minutes. Mixture B is then added, and the temperature is maintained at 115°C for 5 minutes. The material is then introduced into a cold mixer to cool it to 45°C to obtain the final mixture. The final mixture is then introduced into a 75 / 180 two-stage granulation extruder for extrusion granulation to obtain the weather-resistant and fracture-resistant sheath material.

[0050] Comparative Example Comparative Example 1 This comparative example provides a two-core cable. The only difference between this comparative example and Example 1 is that an equal amount of EVA masterbatch is used to replace HDPE resin.

[0051] Comparative Example 2 This comparative example provides a two-core cable. The only difference between this comparative example and Example 1 is that an equal amount of EVA masterbatch is used to replace the PVB resin.

[0052] Comparative Example 3 This comparative example provides a dual-core cable. The only difference between this comparative example and Example 1 is that the toughening fibers are replaced with an equal amount of nano carbon black.

[0053] Comparative Example 4 This comparative example provides a two-core cable. The only difference between this comparative example and Example 1 is that an equal amount of silane coupling agent is used to replace the epoxidized soybean oil.

[0054] Comparative Example 5 This comparative example provides a dual-core cable. The only difference between this comparative example and Example 1 is that an equal amount of toughening fibers are used to replace the nano-carbon black.

[0055] Performance testing The following performance tests were conducted on the two-core cables provided in Examples 1-22 and Comparative Examples 1-5: Mechanical properties: The tensile strength and elongation at break of the two-core cable are tested in accordance with the provisions of GB / T2951.11—2008.

[0056] Flame retardant performance: The flame retardant rating of the two-core cable was tested according to the provisions of GB / T19666—2019, and the results are shown in Table 1.

[0057] Cold resistance: According to the provisions of GB / T5013.4-2008, the elongation at break of the double-core cable after being treated at a low temperature of -35±2℃ for 16 hours was tested, and the results are shown in Table 1.

[0058] Heat resistance: According to the test specifications in GB / T2951.31—2008, the test temperature is specified and the treatment time is 1 hour. The elongation at break of the double-core cable after being treated at a high temperature of 150℃ for 1 hour was tested. The results are shown in Table 1.

[0059] Table 1 Based on Example 1 and Comparative Examples 1-5 and Table 1, it can be seen that, compared with Example 1, the tensile strength, elongation at break, elongation at break after low-temperature treatment, and elongation at break after high-temperature treatment of Comparative Examples 1-5 are all smaller. This indicates that, under the raw material ratio and process conditions of Example 1, it is helpful to improve the mechanical properties, heat resistance, and cold resistance of the twin-core cable, thereby helping to reduce the breakage of the twin-core cable after exposure to sunlight or low-temperature freezing.

[0060] As can be seen from Examples 1-22 and Table 1, the tensile strength, elongation at break, elongation at break after low-temperature treatment, and elongation at break after high-temperature treatment of Examples 1-22 did not change significantly. However, the flame retardant rating of Examples 9-12 and Examples 15-17 decreased. This indicates that the raw material ratios and process conditions of Examples 1-8, Examples 13-14, and Examples 18-22 are conducive to the preparation of dual-core cables with excellent mechanical properties, heat resistance, cold resistance, and flame retardant properties.

[0061] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A dual-core cable for a photovoltaic power generation system, characterized in that: The cable includes a connecting reinforcement, a sheath layer, and two cable cores. Each cable core is covered with a sheath layer, and both sheath layers are integrally connected to the connecting reinforcement. Both the sheath layer and the connecting reinforcement are made of weather-resistant and fracture-resistant sheath material, which includes the following components by weight: 70-88 parts of EVA masterbatch, 20-36 parts of HDPE resin, 15-25 parts of PVB resin, 5-10 parts of toughening fiber, 25-45 parts of nano carbon black, 3-7 parts of epoxidized soybean oil, and 5-30 parts of processing aids. The toughening fiber is aramid fiber; The processing aids include silane coupling agents, inorganic fillers, composite flame retardants, and lubricants. The inorganic fillers are at least one of talc, heavy calcium carbonate, and nano titanium dioxide. The composite flame retardants include aluminum hydroxide, ammonium octamolate, antimony trioxide, and zinc stannate in a weight ratio of (40-50):(10-15):(8-12):(23-33). The lubricant is at least one of petrolatum or stearic acid.

2. The dual-core cable for a photovoltaic power generation system according to claim 1, characterized in that: The silane coupling agent is KH-560 silane coupling agent.

3. The dual-core cable for a photovoltaic power generation system according to claim 1, characterized in that: The HDPE resin is either HDPE resin with the grade H112PC or HDPE resin with the grade HE1105.

4. A dual-core cable for a photovoltaic power generation system as described in any one of claims 1-3, characterized in that, The following steps are used: Cable core manufacturing: An insulating layer is wrapped around the outer wall of a conductor to obtain the cable core; Preparation of weather-resistant and fracture-resistant sheath material: EVA masterbatch, HDPE resin, PVB resin and nano carbon black are mixed according to the formula to obtain mixture A. Toughening fiber, epoxidized soybean oil and processing aids are mixed to obtain mixture B. Mixture A is heated to 110-115℃ and mixed at a constant temperature for 10-15 minutes. Then mixture B is added and mixed at a constant temperature for 5-8 minutes. Then the temperature is lowered to 40-45℃ to obtain the total mixture. The total mixture is extruded and granulated to obtain the weather-resistant and fracture-resistant sheath material. Manufacturing a two-core cable: The weather-resistant and fracture-resistant sheath material is continuously extruded and formed, and the weather-resistant and fracture-resistant sheath material is wrapped around the two cable cores to form a structure in which the two sheath layers are integrally connected with the same connecting rib. After natural cooling, a two-core cable is obtained.

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