Corrosion-resistant polyvinyl chloride insulated cable for aluminum alloy conductors and method for producing the same

Abstract

The application discloses an anti-corrosion polyvinyl chloride insulated cable for aluminum alloy conductors and a production method thereof, and belongs to the technical field of fireproof cables. A flame-retardant encapsulated hollow carbon fiber ternary synergistic flame-retardant system is formed by a cobalt metal framework, ammonium polyphosphate and hollow carbon fibers. The cobalt metal framework is a high-efficiency Lewis acid catalyst, which can quickly catalyze ammonium polyphosphate to form a continuous and high-temperature-resistant composite carbon layer at high temperatures, thereby avoiding acid-base neutralization. The flame-retardant encapsulated hollow carbon fiber has the cobalt metal framework encapsulated in the hollow carbon fiber and the surface coated with ammonium polyphosphate. The special structure can make the hollow carbon fiber simultaneously serve as a physical barrier and a carrier, encapsulate the cobalt metal framework in the cavity, always maintain the catalytic activity of cobalt ions, fix the ammonium polyphosphate on the surface of the hollow carbon fiber by chemical bonds as the carrier, prevent the ammonium polyphosphate from being easily precipitated and migrated, and avoid the problems that the ammonium polyphosphate as a filler is easy to absorb moisture, easy to hydrolyze and poor in compatibility with a matrix.

Description

Technical Field

[0001] This invention belongs to the field of fire-resistant cable technology, specifically a corrosion-resistant polyvinyl chloride insulated cable for aluminum alloy conductors and its production method. Background Technology

[0002] Fire-resistant cables are crucial components that ensure the normal operation of power transmission under extreme conditions such as fires, and their applications are extremely widespread. Although there are many types of fire-resistant cables on the market, numerous problems have been exposed in practical applications. Regarding flame-retardant performance, some fire-resistant cables fail to meet increasingly stringent safety standards.

[0003] Polyvinyl chloride (PVC) is widely used in the sheathing of fire-resistant cables due to its inherent flame-retardant properties. However, PVC has poor stability at high temperatures. When the temperature is too high, PVC will decompose rapidly, releasing a large amount of smoke and dienes containing double bonds. Dienes containing double bonds are highly flammable substances, which will significantly accelerate the spread of flames, seriously affecting the flame-retardant performance of fire-resistant cables. In addition, the smoke produced will also have a strong irritant effect on the human respiratory system, affecting personnel evacuation and rescue work.

[0004] Chinese patent application CN120708988B discloses an aluminum alloy core fireproof cable and its preparation process. The flame retardant in this solution is prepared by mixing a solid solution composed of calcium oxide, magnesium oxide and zinc oxide with a complex of aluminum hydroxide, ammonium polyphosphate and metal acetylacetonate. This effectively inhibits the smoke released by the combustion of polyvinyl chloride and improves the flame retardant performance of the fireproof cable. However, calcium oxide, magnesium oxide and zinc oxide in this solution are alkaline solid solutions, which are prone to acid-base neutralization with ammonium polyphosphate, directly destroying the expansion flame retardant system. Summary of the Invention

[0005] The purpose of this invention is to provide a corrosion-resistant polyvinyl chloride insulated cable for aluminum alloy conductors and its production method. The invention utilizes a flame-retardant encapsulated hollow carbon fiber ternary synergistic flame-retardant system formed by a cobalt metal skeleton, ammonium polyphosphate, and hollow carbon fibers. The cobalt metal skeleton is a highly efficient Lewis acid catalyst that rapidly catalyzes the decomposition of ammonium polyphosphate at high temperatures to generate polyphosphoric acid and metaphosphoric acid, thereby promoting the rapid dehydration and condensation of polyvinyl chloride and carbon fibers to form a continuous, high-temperature resistant composite carbon layer. This effectively blocks heat and oxygen transfer at the source and avoids acid-base neutralization.

[0006] The objective of this invention can be achieved through the following technical solutions: A method for producing a corrosion-resistant polyvinyl chloride insulated cable with an aluminum alloy conductor includes the following steps: Step 1: Using 2-methylimidazole as an organic ligand and cobalt nitrate hexahydrate as a metal source, a coordination self-assembly reaction is carried out to generate a cobalt metal skeleton; using polystyrene and polyacrylonitrile as raw materials, a hollow structure is formed by electrospinning, and then the cobalt metal skeleton is encapsulated in the hollow structure to obtain encapsulated hollow carbon fiber.

[0007] Step 2: The encapsulated hollow carbon fiber is oxidized and etched using a strong oxidizing mixed acid to obtain pretreated encapsulated hollow carbon fiber; flame-retardant encapsulated hollow carbon fiber is obtained by reacting the pretreated encapsulated hollow carbon fiber with ammonium polyphosphate through an amidation reaction.

[0008] Step 3: Mix polyvinyl chloride, dioctyl phthalate, ethylene-vinyl acetate copolymer, flame-retardant encapsulated hollow carbon fiber, antioxidant 1010, talc, and zinc stearate evenly, and extrude the mixture onto the semi-finished product to obtain corrosion-resistant polyvinyl chloride insulated cable for aluminum alloy conductors.

[0009] Furthermore, the mass ratio of polyvinyl chloride, dioctyl phthalate, ethylene-vinyl acetate copolymer, flame-retardant encapsulated hollow carbon fiber, antioxidant 1010, talc, and zinc stearate is 100-110:10-12:10-12:15-17:0.5-0.7:10-12:0.5-0.7.

[0010] Furthermore, the specific preparation steps of the cobalt metal framework are as follows: 2-Methylimidazole and methanol were added to a reaction vessel and stirred for 20-30 min at 20-25℃ and 500-600 r / min. Then, cobalt nitrate hexahydrate was added and stirring was continued for 20-30 min. The mixture was then heated to 80-90℃ and stirred for 5-7 h. The mixture was centrifuged at 8000-9000 r / min for 8-10 min, and the precipitate was collected and washed 2-4 times with methanol to remove impurities. The precipitate was then dried at 60-70℃ for 12-14 h to obtain the cobalt metal framework.

[0011] Furthermore, the ratio of 2-methylimidazole, methanol, and cobalt nitrate hexahydrate used is 19.7-20g: 900-1000mL: 17-18g.

[0012] Furthermore, the specific preparation steps for encapsulated hollow carbon fibers are as follows: Cobalt metal skeleton, polystyrene powder, polyacrylonitrile powder, and N,N-dimethylformamide were added to a reaction vessel and stirred for 20-30 minutes at 20-25℃ and 500-600 r / min until a microemulsion was formed. The microemulsion was then loaded into a syringe equipped with a No. 20 needle and spun under the following conditions: temperature 20-25℃, humidity 55-60%RH, distance between the needle tip and the receiving plate 15-17 cm, spinning voltage 10-15 kV, and syringe advance rate 0.2-0.3 mm / min. The spinning solution was collected on a receiving plate covered with aluminum foil and dried in a constant temperature drying oven at 60-70℃ for 24-26 hours. It was then transferred to a muffle furnace and heated to 800-900℃ in a nitrogen atmosphere and held at that temperature for 2-3 hours to obtain encapsulated hollow carbon fibers with an average length of 50 μm and an average diameter of 500 nm.

[0013] Furthermore, the ratio of cobalt metal skeleton, polystyrene powder, polyacrylonitrile powder and N,N-dimethylformamide is 12-14g: 40-50g: 200-300g: 800-900mL.

[0014] Furthermore, the specific preparation steps for pretreated encapsulated hollow carbon fibers are as follows: The encapsulated hollow carbon fiber was placed in a mixture of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1 and stirred for 15-20 min at 60-70℃ and 50-60 r / min. After filtration, the product was washed with deionized water and anhydrous ethanol until the filtrate was neutral and then vacuum dried at 60-70℃ for 2-4 h to obtain the pretreated encapsulated hollow carbon fiber.

[0015] Furthermore, the ratio of encapsulated hollow carbon fiber to the mixed liquid is 37-40g:800-900mL.

[0016] Furthermore, the specific preparation steps for flame-retardant encapsulated hollow carbon fiber are as follows: Pretreated encapsulated hollow carbon fibers and anhydrous ethanol were added to a reaction vessel and stirred for 20-30 min at 20-25℃ and 500 r / min. Then, ammonium polyphosphate and N,N'-dicyclohexylcarbodiimide were added, heated to 80-90℃, and stirred for 12-14 h. After filtration, the precipitate was washed 2-4 times with deionized water and anhydrous ethanol and dried under vacuum at 60-70℃ for 2-4 h to obtain flame-retardant encapsulated hollow carbon fibers.

[0017] Furthermore, the ratio of pretreated encapsulated hollow carbon fiber, anhydrous ethanol, ammonium polyphosphate, and N,N'-dicyclohexylcarbodiimide is 20-25g: 700-800mL: 5-7g: 100-120mg.

[0018] Furthermore, the specific preparation steps for the semi-finished product are as follows: The aluminum alloy conductor is first wrapped with 2-4 layers of mica tape, then wrapped with 2-4 layers of silicone tape to form an insulation layer. After that, a rock wool rope filling layer, a fiberglass tape binding insulation layer, a corrugated aluminum isolation layer and a fireproof mud fireproof layer are sequentially set on the outside of the insulation layer to obtain a semi-finished product.

[0019] The beneficial effects of this invention are: 1. The corrosion-resistant polyvinyl chloride insulated cable for aluminum alloy conductors prepared by this invention utilizes a flame-retardant encapsulated hollow carbon fiber ternary synergistic flame-retardant system formed by a cobalt metal skeleton, ammonium polyphosphate, and hollow carbon fibers. The cobalt metal skeleton is a highly efficient Lewis acid catalyst that rapidly catalyzes the decomposition of ammonium polyphosphate at high temperatures to generate polyphosphoric acid and metaphosphoric acid, thereby promoting the rapid dehydration and condensation of polyvinyl chloride and carbon fibers to form a continuous, high-temperature resistant composite carbon layer. This effectively blocks heat and oxygen transfer at the source and avoids acid-base neutralization.

[0020] 2. The flame-retardant encapsulated hollow carbon fiber of the present invention has a cobalt metal skeleton encapsulated inside the hollow carbon fiber, with the surface coated with ammonium polyphosphate. This special structure allows the hollow carbon fiber to simultaneously act as a physical barrier and a carrier, encapsulating the cobalt metal skeleton in the cavity to prevent it from agglomerating, oxidizing, and collapsing during high-temperature processing and long-term use, thus maintaining the catalytic activity of cobalt ions. As a carrier, the ammonium polyphosphate is chemically bonded to the surface of the hollow carbon fiber, making it difficult for the ammonium polyphosphate to precipitate and migrate, while avoiding the problems of ammonium polyphosphate as a filler being hygroscopic, hydrolyzed, and having poor compatibility with the matrix.

[0021] 3. This invention significantly improves the tensile strength, impact resistance, and abrasion resistance of PVC insulated cables through the skeletal reinforcement effect of hollow carbon fibers, overcoming the defects of traditional flame-retardant cables that suffer from decreased mechanical properties, easy cracking, and easy wear due to the addition of large amounts of flame retardants, thus extending the service life of the cables. This invention adopts a multi-level synergistic mode of cobalt metal skeleton catalytic carbonization, hollow carbon fiber physical barrier, and ammonium polyphosphate expansion flame retardancy. Utilizing the large specific surface area and porous properties of hollow carbon fibers, it can significantly suppress the release of smoke and toxic gases during combustion, reduce the generation of molten droplets, and greatly improve the safety of the cables in fire scenarios and the safety of escape. Detailed Implementation

[0022] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0023] Example 1: A method for producing a corrosion-resistant polyvinyl chloride insulated cable for aluminum alloy conductors, comprising the following steps: S1: Add 19.7g of 2-methylimidazole and 900mL of methanol to the reaction vessel, stir for 20min at 20℃ and 500r / min, then add 17g of cobalt nitrate hexahydrate and continue stirring for 20min, then heat to 80℃ and continue stirring for 5h, centrifuge at 8000r / min for 8min, collect the precipitate, wash twice with methanol to remove impurities, and dry at 60℃ for 12h to obtain the cobalt metal framework.

[0024] S2: 12g of cobalt metal skeleton, 40g of polystyrene powder, 200g of polyacrylonitrile powder and 800mL of N,N-dimethylformamide were added to a reaction vessel and stirred for 20min at 20℃ and 500r / min to form a microemulsion. The microemulsion was then loaded into a syringe equipped with a No. 20 needle and spun under the following conditions: temperature 20℃, humidity 55%RH, distance between the needle tip and the receiving plate 15cm, spinning voltage 10kV and syringe advance rate 0.2mm / min. The spinning solution was collected on a receiving plate covered with aluminum foil and dried in a 60℃ constant temperature drying oven for 24h. It was then transferred to a muffle furnace and heated to 800℃ in a nitrogen atmosphere and held at that temperature for 2h to obtain encapsulated hollow carbon fibers with an average length of 50μm and an average diameter of 500nm.

[0025] S3: Place 37g of encapsulated hollow carbon fiber in 800mL of a mixture of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1, stir for 15min at 60℃ and 50r / min, filter, wash the product with deionized water and anhydrous ethanol until the filtrate is neutral, and vacuum dry at 60℃ for 2h to obtain pretreated encapsulated hollow carbon fiber.

[0026] S4: Add 20g of pretreated encapsulated hollow carbon fiber and 700mL of anhydrous ethanol to a reaction vessel, stir for 20min at 20℃ and 500r / min, then add 5g of ammonium polyphosphate and 100mg of N,N'-dicyclohexylcarbodiimide, heat to 80℃, continue stirring for 12h, filter, wash the precipitate twice with deionized water and anhydrous ethanol, and vacuum dry at 60℃ for 2h to obtain flame-retardant encapsulated hollow carbon fiber.

[0027] S5: First, wrap two layers of mica tape around the aluminum alloy conductor, then wrap two layers of silicone tape to form an insulation layer. After that, a rock wool rope filling layer, a fiberglass tape binding insulation layer, a corrugated aluminum isolation layer, and a fireproof mud fireproof layer are sequentially set on the outside of the insulation layer to obtain a semi-finished product. Mix 100g of polyvinyl chloride, 10g of dioctyl phthalate, 10g of ethylene-vinyl acetate copolymer, 15g of flame-retardant encapsulated hollow carbon fiber, 0.5g of antioxidant 1010, 10g of talc powder, and 0.5g of zinc stearate evenly, and extrude it on the outside of the semi-finished product to obtain a corrosion-resistant polyvinyl chloride insulated cable for aluminum alloy conductors.

[0028] Example 2: A method for producing a corrosion-resistant polyvinyl chloride insulated cable for aluminum alloy conductors, comprising the following steps: S1: Add 19.85 g of 2-methylimidazole and 950 mL of methanol to a reaction vessel and stir for 25 min at 22.5 °C and 550 r / min. Then add 17.5 g of cobalt nitrate hexahydrate and continue stirring for 25 min. Then heat to 85 °C and continue stirring for 6 h. Centrifuge at 8500 r / min for 9 min, collect the precipitate, wash it three times with methanol to remove impurities, and dry it at 65 °C for 13 h to obtain the cobalt metal framework.

[0029] S2: 13g of cobalt metal skeleton, 45g of polystyrene powder, 250g of polyacrylonitrile powder and 850mL of N,N-dimethylformamide were added to a reaction vessel and stirred for 25min at 22.5℃ and 550r / min until a microemulsion was formed. The microemulsion was then loaded into a syringe equipped with a No. 20 needle and spun under the following conditions: temperature 22.5℃, humidity 57.5%RH, distance between the needle tip and the receiving plate 16cm, spinning voltage 12.5kV and syringe advance rate 0.25mm / min. The spinning solution was collected on a receiving plate covered with aluminum foil and dried in a 65℃ constant temperature drying oven for 25h. It was then transferred to a muffle furnace and heated to 850℃ in a nitrogen atmosphere and held at that temperature for 2.5h to obtain encapsulated hollow carbon fibers with an average length of 50μm and an average diameter of 500nm.

[0030] S3: Place 38.5g of encapsulated hollow carbon fiber in 850mL of a mixture of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1. Stir for 17.5min at 65℃ and 55r / min. Filter the mixture and wash the product with deionized water and anhydrous ethanol until the filtrate is neutral. Dry the product under vacuum at 65℃ for 3h to obtain pretreated encapsulated hollow carbon fiber.

[0031] S4: Add 22.5g of pretreated encapsulated hollow carbon fiber and 750mL of anhydrous ethanol to a reaction vessel, stir for 25min at 22.5℃ and 500r / min, then add 6g of ammonium polyphosphate and 110mg of N,N'-dicyclohexylcarbodiimide, heat to 85℃, continue stirring for 13h, filter, wash the precipitate three times with deionized water and anhydrous ethanol, and vacuum dry at 65℃ for 3h to obtain flame-retardant encapsulated hollow carbon fiber.

[0032] S5: First, wrap 3 layers of mica tape around the aluminum alloy conductor, then wrap 3 layers of silicone tape to form an insulation layer. After that, set a rock wool rope filling layer, a fiberglass tape binding insulation layer, a corrugated aluminum isolation layer and a fireproof mud fireproof layer in sequence to obtain a semi-finished product. Mix 105g of polyvinyl chloride, 11g of dioctyl phthalate, 11g of ethylene-vinyl acetate copolymer, 16g of flame-retardant encapsulated hollow carbon fiber, 0.6g of antioxidant 1010, 11g of talc powder and 0.6g of zinc stearate evenly, and extrude it over the semi-finished product to obtain a corrosion-resistant polyvinyl chloride insulated cable for aluminum alloy conductors.

[0033] Example 3: A method for producing a corrosion-resistant polyvinyl chloride insulated cable for aluminum alloy conductors, comprising the following steps: S1: Add 20g of 2-methylimidazole and 1000mL of methanol to the reaction vessel, stir for 30min at 25℃ and 600r / min, then add 18g of cobalt nitrate hexahydrate and continue stirring for 30min, then heat to 90℃ and continue stirring for 7h, centrifuge at 9000r / min for 10min, collect the precipitate, wash it 4 times with methanol to remove impurities, and dry it at 70℃ for 14h to obtain the cobalt metal framework.

[0034] S2: 14g of cobalt metal skeleton, 50g of polystyrene powder, 300g of polyacrylonitrile powder and 900mL of N,N-dimethylformamide were added to a reaction vessel and stirred at 25℃ and 600r / min for 30min to form a microemulsion. The microemulsion was then loaded into a syringe equipped with a No. 20 needle and spun at 25℃, 60%RH, a distance of 17cm between the needle tip and the receiving plate, a spinning voltage of 15kV and a syringe advance rate of 0.3mm / min. The spinning solution was collected on a receiving plate covered with aluminum foil and dried in a 70℃ constant temperature drying oven for 26h. It was then transferred to a muffle furnace and heated to 900℃ in a nitrogen atmosphere and held at that temperature for 3h to obtain encapsulated hollow carbon fibers with an average length of 50μm and an average diameter of 500nm.

[0035] S3: Place 40g of encapsulated hollow carbon fiber in 900mL of a mixture of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1, stir for 20min at 70℃ and 60r / min, filter, wash the product with deionized water and anhydrous ethanol until the filtrate is neutral, and vacuum dry at 70℃ for 4h to obtain pretreated encapsulated hollow carbon fiber.

[0036] S4: Add 25g of pretreated encapsulated hollow carbon fiber and 800mL of anhydrous ethanol to a reaction vessel, stir for 30min at 25℃ and 500r / min, then add 7g of ammonium polyphosphate and 120mg of N,N'-dicyclohexylcarbodiimide, heat to 90℃, continue stirring for 14h, filter, wash the precipitate 4 times with deionized water and anhydrous ethanol, and vacuum dry at 70℃ for 4h to obtain flame-retardant encapsulated hollow carbon fiber.

[0037] S5: First, wrap 4 layers of mica tape around the aluminum alloy conductor, then wrap 4 layers of silicone tape to form an insulation layer. After that, a rock wool rope filling layer, a fiberglass tape binding heat insulation layer, a corrugated aluminum isolation layer, and a fireproof mud fireproof layer are sequentially set on the outside of the insulation layer to obtain a semi-finished product. Mix 110g of polyvinyl chloride, 12g of dioctyl phthalate, 12g of ethylene-vinyl acetate copolymer, 17g of flame-retardant encapsulated hollow carbon fiber, 0.7g of antioxidant 1010, 12g of talc powder, and 0.7g of zinc stearate evenly, and extrude it on the outside of the semi-finished product to obtain a corrosion-resistant polyvinyl chloride insulated cable for aluminum alloy conductors.

[0038] Comparative Example 1: Based on Example 3, the cobalt metal skeleton in step S2 was removed, while the rest remained unchanged, and a corrosion-resistant polyvinyl chloride insulated cable for aluminum alloy conductors was prepared.

[0039] Comparative Example 2: Based on Example 3, the encapsulated hollow carbon fiber in step S3 was replaced with a mixture of cobalt metal skeleton and commercially available carbon fiber, while the rest remained unchanged, to prepare a corrosion-resistant polyvinyl chloride insulated cable for aluminum alloy conductors.

[0040] Comparative Example 3: Based on Example 3, the flame-retardant encapsulated hollow carbon fiber in step S5 was replaced with a mixture of pretreated encapsulated hollow carbon fiber and ammonium polyphosphate at a mass ratio of 25:7, while the rest remained unchanged, to prepare a corrosion-resistant polyvinyl chloride insulated cable for aluminum alloy conductors.

[0041] Performance tests were conducted on Examples 1-3 and Comparative Examples 1-3. The limiting oxygen index of the corrosion-resistant PVC insulated cable was determined according to GB / T2406.2-2009 "Determination of Combustion Behavior by Oxygen Index Method for Plastics". Tensile strength was tested according to GB / T2951.11-2008 "General Test Methods for Insulation and Sheath Materials of Cables and Optical Fibers". The corrosion-resistant PVC insulated cable was immersed in a 25 wt% hydrochloric acid solution at 25°C for 30 days, and the tensile strength was tested again. The corrosion-resistant PVC insulated cable was then immersed in a 25 wt% hydrochloric acid solution, a 25 wt% sodium hydroxide solution, a 25 wt% sodium chloride solution, and an aqueous solution under the same conditions for 200 hours. The surface corrosion was observed after immersion, and the corrosion resistance was tested. The results are shown in Table 1. Table 1

[0042] As shown in Table 1, the cobalt-free metal skeleton in Comparative Example 1 provides efficient Lewis acid catalysis, but it cannot quickly catalyze the decomposition of ammonium polyphosphate and promote the dehydration of the matrix into carbon. It is difficult to form a continuous and dense high-temperature resistant carbon layer, the limiting oxygen index decreases, and the fire barrier ability is significantly weakened. The hollow carbon fiber is supported and reinforced by the cobalt-free metal skeleton, but the fiber structure stability decreases, the skeleton reinforcement effect weakens, the initial tensile strength and the strength after hydrochloric acid immersion are significantly reduced, and the lack of a dense protective layer formed by catalytic carbonization makes the insulation layer easy to be corroded in acid, alkali and salt environments, resulting in poor long-term stability.

[0043] In Comparative Example 2, without hollow carbon fiber encapsulation and protection, the cobalt metal skeleton is directly exposed during processing and use, making it prone to agglomeration, oxidation, and structural collapse. The catalytic activity is rapidly lost, and it cannot stably play a role in carbonization. Physical mixing leads to uneven dispersion of the cobalt metal skeleton and carbon fiber, resulting in numerous interface defects and significant stress concentration. The initial tensile strength and the strength after acid corrosion resistance are the lowest among the three comparative examples, and the cable is prone to cracking and wear.

[0044] In Comparative Example 3, the ammonium polyphosphate was only physically mixed without chemical bonding. It was prone to moisture absorption, hydrolysis, migration, and precipitation, and could not form a stable synergy with the hollow carbon fiber and cobalt metal skeleton. With long-term use, its flame retardant performance deteriorated. The free ammonium polyphosphate was a polar filler with poor compatibility with the PVC matrix and was prone to agglomeration, which led to a decrease in tensile strength and acid corrosion resistance. The easy loss of ammonium polyphosphate resulted in an incomplete char system, discontinuous protective layer, poor acid, alkali and salt resistance, and slight corrosion.

[0045] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the invention.

Claims

1. A method for producing a corrosion-resistant polyvinyl chloride insulated cable with an aluminum alloy conductor, characterized in that, Includes the following steps: Step 1: Using 2-methylimidazole as an organic ligand and cobalt nitrate hexahydrate as a metal source, a coordination self-assembly reaction is carried out to generate a cobalt metal skeleton; using polystyrene and polyacrylonitrile as raw materials, a hollow structure is formed by electrospinning, and then the cobalt metal skeleton is encapsulated in the hollow structure to obtain encapsulated hollow carbon fiber. Step 2: Use strong oxidizing mixed acid to oxidize and acidify the encapsulated hollow carbon fiber to obtain pretreated encapsulated hollow carbon fiber. Flame-retardant encapsulated hollow carbon fibers are obtained by reacting pretreated encapsulated hollow carbon fibers with ammonium polyphosphate through an amidation reaction. Step 3: Mix polyvinyl chloride, dioctyl phthalate, ethylene-vinyl acetate copolymer, flame-retardant encapsulated hollow carbon fiber, antioxidant 1010, talc, and zinc stearate evenly, and extrude the mixture onto the semi-finished product to obtain corrosion-resistant polyvinyl chloride insulated cable for aluminum alloy conductors.

2. The method for producing a corrosion-resistant polyvinyl chloride insulated cable for aluminum alloy conductors according to claim 1, characterized in that, The mass ratio of polyvinyl chloride, dioctyl phthalate, ethylene-vinyl acetate copolymer, flame-retardant encapsulated hollow carbon fiber, antioxidant 1010, talc, and zinc stearate is 100-110:10-12:10-12:15-17:0.5-0.7:10-12:0.5-0.

7.

3. The method for producing a corrosion-resistant polyvinyl chloride insulated cable for aluminum alloy conductors according to claim 1, characterized in that, The specific preparation steps for the cobalt metal framework are as follows: 2-Methylimidazole and methanol were added to a reaction vessel and stirred for 20-30 min at 20-25℃ and 500-600 r / min. Then, cobalt nitrate hexahydrate was added and stirring was continued for 20-30 min. The mixture was then heated to 80-90℃ and stirred for 5-7 h. The mixture was centrifuged at 8000-9000 r / min for 8-10 min, and the precipitate was collected and washed 2-4 times with methanol to remove impurities. The precipitate was then dried at 60-70℃ for 12-14 h to obtain the cobalt metal framework.

4. The method for producing a corrosion-resistant polyvinyl chloride insulated cable for aluminum alloy conductors according to claim 3, characterized in that, The ratio of 2-methylimidazole, methanol, and cobalt nitrate hexahydrate used is 19.7-20g: 900-1000mL: 17-18g.

5. The method for producing a corrosion-resistant polyvinyl chloride insulated cable for aluminum alloy conductors according to claim 1, characterized in that, The specific preparation steps of the encapsulated hollow carbon fiber are as follows: Cobalt metal skeleton, polystyrene powder, polyacrylonitrile powder, and N,N-dimethylformamide were added to a reaction vessel and stirred for 20-30 minutes at 20-25℃ and 500-600 r / min until a microemulsion was formed. The microemulsion was then loaded into a syringe equipped with a No. 20 needle and spun under the following conditions: temperature 20-25℃, humidity 55-60%RH, distance between the needle tip and the receiving plate 15-17 cm, spinning voltage 10-15 kV, and syringe advance rate 0.2-0.3 mm / min. The spinning solution was collected on a receiving plate covered with aluminum foil and dried in a constant temperature drying oven at 60-70℃ for 24-26 hours. It was then transferred to a muffle furnace and heated to 800-900℃ in a nitrogen atmosphere and held at that temperature for 2-3 hours to obtain encapsulated hollow carbon fibers with an average length of 50 μm and an average diameter of 500 nm.

6. The method for producing a corrosion-resistant polyvinyl chloride insulated cable for aluminum alloy conductors according to claim 5, characterized in that, The ratio of the cobalt metal skeleton, polystyrene powder, polyacrylonitrile powder and N,N-dimethylformamide is 12-14g: 40-50g: 200-300g: 800-900mL.

7. The method for producing a corrosion-resistant polyvinyl chloride insulated cable for aluminum alloy conductors according to claim 1, characterized in that, The specific preparation steps for the pretreated encapsulated hollow carbon fiber are as follows: Encapsulated hollow carbon fibers are placed in a mixture of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1, stirred for 15-20 min at 60-70℃ and 50-60 r / min, filtered, and the product is washed with deionized water and anhydrous ethanol until the filtrate is neutral. The product is then vacuum dried at 60-70℃ for 2-4 h to obtain pretreated encapsulated hollow carbon fibers. The ratio of the encapsulated hollow carbon fiber to the mixed liquid is 37-40g:800-900mL.

8. The method for producing a corrosion-resistant polyvinyl chloride insulated cable for aluminum alloy conductors according to claim 1, characterized in that, The specific preparation steps of the flame-retardant encapsulated hollow carbon fiber are as follows: Pretreated encapsulated hollow carbon fibers and anhydrous ethanol were added to a reaction vessel and stirred for 20-30 min at 20-25℃ and 500 r / min. Then, ammonium polyphosphate and N,N'-dicyclohexylcarbodiimide were added, heated to 80-90℃, and stirred for 12-14 h. After filtration, the precipitate was washed 2-4 times with deionized water and anhydrous ethanol and dried under vacuum at 60-70℃ for 2-4 h to obtain flame-retardant encapsulated hollow carbon fibers. The ratio of the pretreated encapsulated hollow carbon fiber, anhydrous ethanol, ammonium polyphosphate, and N,N'-dicyclohexylcarbodiimide is 20-25g: 700-800mL: 5-7g: 100-120mg.

9. The method for producing a corrosion-resistant polyvinyl chloride insulated cable for aluminum alloy conductors according to claim 1, characterized in that, The specific preparation steps for the semi-finished product are as follows: The aluminum alloy conductor is first wrapped with 2-4 layers of mica tape, then wrapped with 2-4 layers of silicone tape to form an insulation layer. After that, a rock wool rope filling layer, a fiberglass tape binding insulation layer, a corrugated aluminum isolation layer and a fireproof mud fireproof layer are sequentially set on the outside of the insulation layer to obtain a semi-finished product.

10. A corrosion-resistant polyvinyl chloride insulated cable for aluminum alloy conductors, characterized in that, It is produced by the production method described in any one of claims 1-9.

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