Flame-retardant cross-linked cable material for charging pile cable and preparation method of flame-retardant cross-linked cable material

Abstract

The invention relates to a flame-retardant cross-linked cable material for a charging pile cable and a preparation method of the flame-retardant cross-linked cable material, and belongs to the technical field of cable materials. The plasticizer with a fat long chain in the structure is prepared, the tail end of the fat long chain of the plasticizer is provided with double bonds, the plasticizer can normally play a plasticizing role before initiation of crosslinking, the acting force between molecular chains is reduced, the processing difficulty of polyvinyl chloride is reduced, and in the crosslinking process after extrusion and plasticization, the strength of polyvinyl chloride is improved. A double bond at the tail end of a fat long chain of the plasticizer and a polyvinyl chloride molecular chain can be cross-linked and bonded in a cross-linked network under the action of an initiator, so that the migration risk of the plasticizer is eliminated, the durability and the environmental protection property of the polyvinyl chloride cable are improved, the strength influence of the cross-linked network due to the addition of the plasticizer is reduced, and the service life of the cable is prolonged. By using the plasticizer disclosed by the invention, polyvinyl chloride can have better strength after crosslinking while having good processing flowability and flexibility in a processing stage.

Description

Technical Field

[0001] This invention belongs to the field of cable material technology, specifically, it relates to a flame-retardant cross-linked cable material for charging pile cables and its preparation method, and more specifically, it relates to a flame-retardant cross-linked cable material for the outer sheath of charging pile cables and its preparation method. Background Technology

[0002] Polyvinyl chloride (PVC) cable materials are widely used in the wire and cable industry due to their excellent mechanical properties, electrical insulation, chemical corrosion resistance, and cost advantages. With the rapid development of the electric vehicle industry, charging pile cables face increasingly demanding operating environments. These cables need to withstand high-temperature operating conditions under high current loads for extended periods. However, PVC has poor aging resistance, and under long-term high-temperature operating conditions, the tensile strength and elongation at break of PVC cables will decrease to varying degrees. Furthermore, to ensure sufficient safety performance, a large amount of flame retardant needs to be added during the preparation of PVC cables. While these flame retardants provide protection, they also significantly increase the processing difficulty of PVC cables. Although the processing difficulty of PVC can be reduced by adding plasticizers, this also leads to a decrease in the mechanical properties of PVC. To address these technical deficiencies, this invention provides a flame-retardant cross-linked cable material for charging pile cables and its preparation method. Summary of the Invention

[0003] The purpose of this invention is to provide a flame-retardant cross-linked cable material for charging pile cables and its preparation method, in order to solve the problems mentioned in the background art.

[0004] The objective of this invention can be achieved through the following technical solutions:

[0005] A method for preparing a flame-retardant cross-linked cable material for charging pile cables includes the following steps:

[0006] The first step involves esterifying 4-chloromethyl phthalic acid with 2-ethyl-5-hexen-1-ol to obtain a reactive plasticizer.

[0007] The reaction process is as follows: 4-chloromethylphthalic acid, 2-ethyl-5-hexen-1-ol, dicyclohexylcarbodiimide, 4-dimethylaminopyridine, and tetrahydrofuran are mixed in a reaction vessel and reacted at a temperature of 20-50℃ for 4-10 hours. After the reaction is completed, the reaction solution is poured into deionized water, the solid is separated by filtration, and the obtained solid is washed with deionized water and dried to obtain a reactive plasticizer.

[0008] The second step involves reacting the reactive plasticizer with sodium disulfide via a nucleophilic substitution reaction to obtain a heat-repairing modifier with plasticizing function.

[0009] The reaction process is as follows: Sodium sulfide, sulfur, and deionized water are mixed in a reaction vessel and reacted at 60-80℃ for 1-2 hours to obtain sodium disulfide. Then, a reactive plasticizer, tetrabutylammonium bromide, and toluene are added to the system, and the reaction is continued at 45-65℃ for 2-4 hours. After the reaction is completed, the organic phase is separated and the solvent is removed by rotary evaporation. The remaining solid is eluted by silica gel column chromatography to obtain a heat-repairing modifier with plasticizing function.

[0010] The third step involves mixing polyvinyl chloride, flame retardant, initiator, crosslinking agent, lubricant, stabilizer, antioxidant, and heat-repairing modifier with plasticizing function, and then melting and extruding the mixture through a twin-screw extruder to obtain flame-retardant crosslinked cable material.

[0011] Furthermore, the flame retardant is at least one of aluminum hydroxide and magnesium hydroxide.

[0012] Furthermore, the initiator is at least one of dicumyl peroxide and bis(tert-butylperoxyisopropyl)benzene.

[0013] Furthermore, the crosslinking agent is triallyl isocyanurate.

[0014] Furthermore, the lubricant is at least one of calcium stearate and polyethylene wax.

[0015] Furthermore, the stabilizer is a calcium-zinc stabilizer.

[0016] Furthermore, the antioxidant is at least one of antioxidant 1010, antioxidant 1076, and antioxidant 168.

[0017] Furthermore, the temperature of the melt extrusion is 150–160°C.

[0018] Furthermore, the mass ratio of polyvinyl chloride, flame retardant, initiator, crosslinking agent, lubricant, stabilizer, antioxidant, and heat-repairing modifier with plasticizing function is 100:40~60:2~4:1~2:0.5~2:3~6:0.3~1:20~30.

[0019] A flame-retardant cross-linked cable material for charging pile cables, which is prepared by any of the above steps.

[0020] The beneficial effects of this invention are:

[0021] 1) This invention prepares a plasticizer with long aliphatic chains in its structure, and the ends of the long aliphatic chains of the plasticizer have double bonds. Before cross-linking is initiated, the plasticizer can normally play a plasticizing role, reducing the interaction forces between molecular chains and reducing the processing difficulty of polyvinyl chloride. During the cross-linking process after extrusion plasticization, the double bonds at the ends of the long aliphatic chains of the plasticizer can cross-link and bond with the polyvinyl chloride molecular chains in the cross-linking network under the action of the initiator. This not only eliminates the migration risk of the plasticizer and improves the durability and environmental friendliness of polyvinyl chloride cables, but also reduces the influence of the added plasticizer on the strength of the cross-linking network. Using the plasticizer of this invention enables polyvinyl chloride to have good processing fluidity and flexibility during the processing stage, while having better strength after cross-linking.

[0022] 2) After initiating crosslinking, the plasticizer of the present invention can also introduce disulfide bonds into the polyvinyl chloride molecular chain. The introduced disulfide bonds can not only improve the toughness of polyvinyl chloride cables and achieve a balance between rigidity and flexibility, but also spontaneously break and reorganize under high temperature working conditions, eliminate the aging stress generated by polyvinyl chloride cables, and reduce the impact of long-term high temperature environment on the tensile strength and elongation at break of polyvinyl chloride cables. Detailed Implementation

[0023] The technical solution 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.

[0024] It should be understood that the expression “one or more of…” individually includes each of the objects described after the expression, as well as various different combinations of two or more of the described objects, unless otherwise understood from the context and usage. The expression “and / or” combined with three or more described objects should be understood to have the same meaning, unless otherwise understood from the context.

[0025] It should be understood that the use of “including,” “having,” or “containing,” including its grammatical synonyms, should generally be understood as open-ended and non-restrictive, for example, not excluding other unstated elements or steps, unless otherwise specifically stated or understood from the context.

[0026] It should be understood that the order of the steps or the order in which certain actions are performed is not important as long as the invention remains operational. Furthermore, two or more steps or actions can be performed simultaneously.

[0027] Furthermore, the numerical ranges and parameters used to define the present invention are approximate values, and the relevant values ​​in the specific embodiments have been presented as precisely as possible. However, any value inevitably contains standard deviations due to individual test methods. Therefore, unless explicitly stated otherwise, it should be understood that all ranges, quantities, values, and percentages used in this disclosure are modified with the word "approximately". Here, "approximately" generally means that the actual value is within plus or minus 10%, 5%, 1%, or 0.5% of a specific value or range.

[0028] Example 1

[0029] A method for preparing a flame-retardant cross-linked cable material for charging pile cables includes the following steps:

[0030] Step 1: According to the mass fractions, 20 parts of 4-chloromethylphthalic acid, 26 parts of 2-ethyl-5-hexen-1-ol, 40 parts of dicyclohexylcarbodiimide, 0.4 parts of 4-dimethylaminopyridine, and 320 parts of tetrahydrofuran are mixed in a reaction vessel and reacted at 20°C for 10 hours. After the reaction is completed, the reaction solution is poured into deionized water, the solid is filtered to separate the solid, and the obtained solid is washed with deionized water and dried to obtain the reactive plasticizer.

[0031] Step 2: By mass, 7.8 parts sodium sulfide, 3.8 parts sulfur, and 45 parts deionized water are mixed in a reaction vessel and reacted at 60°C for 2 hours to obtain sodium disulfide. Then, 30 parts reactive plasticizer, 0.4 parts tetrabutylammonium bromide, and 120 parts toluene are added to the system, and the reaction is continued at 45°C for 4 hours. After the reaction is completed, the organic phase is separated and the solvent is removed by rotary evaporation. The remaining solid is eluted by silica gel column chromatography to obtain a heat-repairing modifier with plasticizing function.

[0032] The third step involves mixing 100 parts polyvinyl chloride, 40 parts aluminum hydroxide, 2 parts dicumyl peroxide, 1 part triallyl isocyanurate, 0.5 parts calcium stearate, 3 parts calcium-zinc stabilizer CZ-113, 0.3 parts antioxidant 1010, and 20 parts heat-repairing modifier with plasticizing function by weight. The mixture is then melt-extruded through a twin-screw extruder at an extrusion temperature of 150°C to obtain flame-retardant cross-linked cable material.

[0033] A flame-retardant cross-linked cable material for charging pile cables, which is prepared by the above steps.

[0034] Example 2

[0035] A method for preparing a flame-retardant cross-linked cable material for charging pile cables includes the following steps:

[0036] Step 1: According to the mass fractions, 20 parts of 4-chloromethylphthalic acid, 26 parts of 2-ethyl-5-hexen-1-ol, 40 parts of dicyclohexylcarbodiimide, 0.4 parts of 4-dimethylaminopyridine, and 320 parts of tetrahydrofuran are mixed in a reaction vessel and reacted at 20°C for 10 hours. After the reaction is completed, the reaction solution is poured into deionized water, the solid is filtered to separate the solid, and the obtained solid is washed with deionized water and dried to obtain the reactive plasticizer.

[0037] Step 2: By mass, 7.8 parts sodium sulfide, 3.8 parts sulfur, and 45 parts deionized water are mixed in a reaction vessel and reacted at 60°C for 2 hours to obtain sodium disulfide. Then, 30 parts reactive plasticizer, 0.4 parts tetrabutylammonium bromide, and 120 parts toluene are added to the system, and the reaction is continued at 45°C for 4 hours. After the reaction is completed, the organic phase is separated and the solvent is removed by rotary evaporation. The remaining solid is eluted by silica gel column chromatography to obtain a heat-repairing modifier with plasticizing function.

[0038] The third step involves mixing 100 parts polyvinyl chloride, 40 parts magnesium hydroxide, 2 parts dicumyl peroxide, 1 part triallyl isocyanurate, 0.5 parts calcium stearate, 3 parts calcium-zinc stabilizer CZ-113, 0.3 parts antioxidant 1010, and 20 parts heat-repairing modifier with plasticizing function by weight. The mixture is then melt-extruded through a twin-screw extruder at an extrusion temperature of 150°C to obtain flame-retardant cross-linked cable material.

[0039] A flame-retardant cross-linked cable material for charging pile cables, which is prepared by the above steps.

[0040] Example 3

[0041] A method for preparing a flame-retardant cross-linked cable material for charging pile cables includes the following steps:

[0042] Step 1: According to the mass fractions, 20 parts of 4-chloromethylphthalic acid, 26 parts of 2-ethyl-5-hexen-1-ol, 40 parts of dicyclohexylcarbodiimide, 0.4 parts of 4-dimethylaminopyridine, and 320 parts of tetrahydrofuran are mixed in a reaction vessel and reacted at 35°C for 6 hours. After the reaction is completed, the reaction solution is poured into deionized water, the solid is filtered to separate the solid, and the obtained solid is washed with deionized water and dried to obtain the reactive plasticizer.

[0043] Step 2: By mass, 7.8 parts sodium sulfide, 3.8 parts sulfur, and 45 parts deionized water are mixed in a reaction vessel and reacted at 70°C for 1.5 hours to obtain sodium disulfide. Then, 30 parts reactive plasticizer, 0.4 parts tetrabutylammonium bromide, and 120 parts toluene are added to the system, and the reaction is continued at 55°C for 3 hours. After the reaction is completed, the organic phase is separated and the solvent is removed by rotary evaporation. The remaining solid is eluted by silica gel column chromatography to obtain a heat-repairing modifier with plasticizing function.

[0044] The third step involves mixing 100 parts by weight of polyvinyl chloride, 50 parts of aluminum hydroxide, 3 parts of bis(tert-butylperoxyisopropyl)benzene, 1.5 parts of triallyl isocyanurate, 1.25 parts of polyethylene wax, 4.5 parts of calcium-zinc stabilizer CZ-116, 0.5 parts of antioxidant 1076, 0.15 parts of antioxidant 168, and 25 parts of a heat-repairing modifier with plasticizing function. The mixture is then melt-extruded through a twin-screw extruder at an extrusion temperature of 155°C to obtain flame-retardant cross-linked cable material.

[0045] A flame-retardant cross-linked cable material for charging pile cables, which is prepared by the above steps.

[0046] Example 4

[0047] A method for preparing a flame-retardant cross-linked cable material for charging pile cables includes the following steps:

[0048] Step 1: According to the mass fractions, 20 parts of 4-chloromethylphthalic acid, 26 parts of 2-ethyl-5-hexen-1-ol, 40 parts of dicyclohexylcarbodiimide, 0.4 parts of 4-dimethylaminopyridine, and 320 parts of tetrahydrofuran are mixed in a reaction vessel and reacted at 35°C for 6 hours. After the reaction is completed, the reaction solution is poured into deionized water, the solid is filtered to separate the solid, and the obtained solid is washed with deionized water and dried to obtain the reactive plasticizer.

[0049] Step 2: By mass, 7.8 parts sodium sulfide, 3.8 parts sulfur, and 45 parts deionized water are mixed in a reaction vessel and reacted at 70°C for 1.5 hours to obtain sodium disulfide. Then, 30 parts reactive plasticizer, 0.4 parts tetrabutylammonium bromide, and 120 parts toluene are added to the system, and the reaction is continued at 55°C for 3 hours. After the reaction is completed, the organic phase is separated and the solvent is removed by rotary evaporation. The remaining solid is eluted by silica gel column chromatography to obtain a heat-repairing modifier with plasticizing function.

[0050] The third step involves mixing 100 parts by weight of polyvinyl chloride, 50 parts by weight of magnesium hydroxide, 3 parts by weight of bis(tert-butylperoxyisopropyl)benzene, 1.5 parts by weight of triallyl isocyanurate, 1.25 parts by weight of polyethylene wax, 4.5 parts by weight of calcium-zinc stabilizer CZ-116, 0.5 parts by weight of antioxidant 1076, 0.15 parts by weight of antioxidant 168, and 25 parts by weight of heat-repairing modifier with plasticizing function. The mixture is then melt-extruded through a twin-screw extruder at an extrusion temperature of 155°C to obtain flame-retardant cross-linked cable material.

[0051] A flame-retardant cross-linked cable material for charging pile cables, which is prepared by the above steps.

[0052] Example 5

[0053] A method for preparing a flame-retardant cross-linked cable material for charging pile cables includes the following steps:

[0054] Step 1: According to the mass fractions, 20 parts of 4-chloromethylphthalic acid, 26 parts of 2-ethyl-5-hexen-1-ol, 40 parts of dicyclohexylcarbodiimide, 0.4 parts of 4-dimethylaminopyridine, and 320 parts of tetrahydrofuran are mixed in a reaction vessel and reacted at 50°C for 4 hours. After the reaction is completed, the reaction solution is poured into deionized water, the solid is filtered to separate the solid, and the obtained solid is washed with deionized water and dried to obtain the reactive plasticizer.

[0055] Step 2: By mass, 7.8 parts sodium sulfide, 3.8 parts sulfur, and 45 parts deionized water are mixed in a reaction vessel and reacted at 80°C for 1 hour to obtain sodium disulfide. Then, 30 parts reactive plasticizer, 0.4 parts tetrabutylammonium bromide, and 120 parts toluene are added to the system, and the reaction is continued at 65°C for 2 hours. After the reaction is completed, the organic phase is separated and the solvent is removed by rotary evaporation. The remaining solid is eluted by silica gel column chromatography to obtain a heat-repairing modifier with plasticizing function.

[0056] The third step involves mixing 100 parts polyvinyl chloride, 60 parts aluminum hydroxide, 4 parts dicumyl peroxide, 2 parts triallyl isocyanurate, 2 parts polyethylene wax, 6 parts calcium-zinc stabilizer CZ-113, 0.9 parts antioxidant 1010, 0.1 parts antioxidant 168, and 30 parts heat-repairing modifier with plasticizing function by weight. The mixture is then melt-extruded through a twin-screw extruder at an extrusion temperature of 160°C to obtain flame-retardant cross-linked cable material.

[0057] A flame-retardant cross-linked cable material for charging pile cables, which is prepared by the above steps.

[0058] Example 6

[0059] A method for preparing a flame-retardant cross-linked cable material for charging pile cables includes the following steps:

[0060] Step 1: According to the mass fractions, 20 parts of 4-chloromethylphthalic acid, 26 parts of 2-ethyl-5-hexen-1-ol, 40 parts of dicyclohexylcarbodiimide, 0.4 parts of 4-dimethylaminopyridine, and 320 parts of tetrahydrofuran are mixed in a reaction vessel and reacted at 50°C for 4 hours. After the reaction is completed, the reaction solution is poured into deionized water, the solid is filtered to separate the solid, and the obtained solid is washed with deionized water and dried to obtain the reactive plasticizer.

[0061] Step 2: By mass, 7.8 parts sodium sulfide, 3.8 parts sulfur, and 45 parts deionized water are mixed in a reaction vessel and reacted at 80°C for 1 hour to obtain sodium disulfide. Then, 30 parts reactive plasticizer, 0.4 parts tetrabutylammonium bromide, and 120 parts toluene are added to the system, and the reaction is continued at 65°C for 2 hours. After the reaction is completed, the organic phase is separated and the solvent is removed by rotary evaporation. The remaining solid is eluted by silica gel column chromatography to obtain a heat-repairing modifier with plasticizing function.

[0062] The third step involves mixing 100 parts polyvinyl chloride, 60 parts magnesium hydroxide, 4 parts dicumyl peroxide, 2 parts triallyl isocyanurate, 2 parts polyethylene wax, 6 parts calcium-zinc stabilizer CZ-113, 0.9 parts antioxidant 1010, 0.1 parts antioxidant 168, and 30 parts heat-repairing modifier with plasticizing function by weight. The mixture is then melt-extruded through a twin-screw extruder at an extrusion temperature of 160°C to obtain flame-retardant cross-linked cable material.

[0063] A flame-retardant cross-linked cable material for charging pile cables, which is prepared by the above steps.

[0064] Comparative Example 1

[0065] The difference between this comparative example and Example 5 is that, instead of preparing a separate heat-repairing modifier with plasticizing function, an equal mass of commercially available di(2-ethylhexyl) phthalate was used to replace the heat-repairing modifier with plasticizing function in Example 5.

[0066] A method for preparing a flame-retardant cross-linked cable material for charging pile cables includes the following steps:

[0067] By weight, 100 parts of polyvinyl chloride, 60 parts of aluminum hydroxide, 4 parts of dicumyl peroxide, 2 parts of triallyl isocyanurate, 2 parts of polyethylene wax, 6 parts of calcium-zinc stabilizer CZ-113, 0.9 parts of antioxidant 1010, 0.1 parts of antioxidant 168, and 30 parts of di(2-ethylhexyl) phthalate are mixed and then melt-extruded through a twin-screw extruder at an extrusion temperature of 160℃ to obtain flame-retardant cross-linked cable material.

[0068] A flame-retardant cross-linked cable material for charging pile cables, which is prepared by the above steps.

[0069] Comparative Example 2

[0070] The difference between this comparative example and Example 6 is that, instead of preparing a separate heat-repairing modifier with plasticizing function, an equal mass of commercially available di(2-ethylhexyl) phthalate was used to replace the heat-repairing modifier with plasticizing function in Example 6.

[0071] A method for preparing a flame-retardant cross-linked cable material for charging pile cables includes the following steps:

[0072] By weight, 100 parts of polyvinyl chloride, 60 parts of magnesium hydroxide, 4 parts of dicumyl peroxide, 2 parts of triallyl isocyanurate, 2 parts of polyethylene wax, 6 parts of calcium-zinc stabilizer CZ-113, 0.9 parts of antioxidant 1010, 0.1 parts of antioxidant 168, and 30 parts of di(2-ethylhexyl) phthalate are mixed and then melt-extruded through a twin-screw extruder at an extrusion temperature of 160℃ to obtain flame-retardant cross-linked cable material.

[0073] A flame-retardant cross-linked cable material for charging pile cables, which is prepared by the above steps.

[0074] Comparative Example 3

[0075] The difference between this comparative example and Example 5 is that only a reactive plasticizer was prepared, and an equal mass of the reactive plasticizer was used to replace the heat-repairing modifier with plasticizing function in Example 5.

[0076] A method for preparing a flame-retardant cross-linked cable material for charging pile cables includes the following steps:

[0077] Step 1: According to the mass fractions, 20 parts of 4-chloromethylphthalic acid, 26 parts of 2-ethyl-5-hexen-1-ol, 40 parts of dicyclohexylcarbodiimide, 0.4 parts of 4-dimethylaminopyridine, and 320 parts of tetrahydrofuran are mixed in a reaction vessel and reacted at 50°C for 4 hours. After the reaction is completed, the reaction solution is poured into deionized water, the solid is filtered to separate the solid, and the obtained solid is washed with deionized water and dried to obtain the reactive plasticizer.

[0078] The second step involves mixing 100 parts polyvinyl chloride, 60 parts aluminum hydroxide, 4 parts dicumyl peroxide, 2 parts triallyl isocyanurate, 2 parts polyethylene wax, 6 parts calcium-zinc stabilizer CZ-113, 0.9 parts antioxidant 1010, 0.1 parts antioxidant 168, and 30 parts reactive plasticizer by weight, and then melting and extruding the mixture through a twin-screw extruder at an extrusion temperature of 160℃ to obtain flame-retardant cross-linked cable material.

[0079] A flame-retardant cross-linked cable material for charging pile cables, which is prepared by the above steps.

[0080] Comparative Example 4

[0081] The difference between this comparative example and Example 6 is that only a reactive plasticizer was prepared, and an equal mass of the reactive plasticizer was used to replace the heat-repairing modifier with plasticizing function in Example 6.

[0082] A method for preparing a flame-retardant cross-linked cable material for charging pile cables includes the following steps:

[0083] Step 1: According to the mass fractions, 20 parts of 4-chloromethylphthalic acid, 26 parts of 2-ethyl-5-hexen-1-ol, 40 parts of dicyclohexylcarbodiimide, 0.4 parts of 4-dimethylaminopyridine, and 320 parts of tetrahydrofuran are mixed in a reaction vessel and reacted at 50°C for 4 hours. After the reaction is completed, the reaction solution is poured into deionized water, the solid is filtered to separate the solid, and the obtained solid is washed with deionized water and dried to obtain the reactive plasticizer.

[0084] The second step involves mixing 100 parts by weight of polyvinyl chloride, 60 parts of magnesium hydroxide, 4 parts of dicumyl peroxide, 2 parts of triallyl isocyanurate, 2 parts of polyethylene wax, 6 parts of calcium-zinc stabilizer CZ-113, 0.9 parts of antioxidant 1010, 0.1 parts of antioxidant 168, and 30 parts of reactive plasticizer, and then melting and extruding the mixture through a twin-screw extruder at an extrusion temperature of 160°C to obtain flame-retardant cross-linked cable material.

[0085] A flame-retardant cross-linked cable material for charging pile cables, which is prepared by the above steps.

[0086] Experimental Example 1

[0087] The flame-retardant cross-linked cable materials obtained in Examples 1-6 and Comparative Examples 1-4 were extruded and plasticized, and then placed in a high-temperature cross-linking pipe for cross-linking and molding. The cross-linking conditions for the flame-retardant cross-linked cable materials obtained in Examples 1-2 were cross-linking at 180°C for 30 min, and the cross-linking conditions for the flame-retardant cross-linked cable materials obtained in Examples 3-4 were cross-linking at 185°C for 25 min. The flame-retardant cross-linked cable materials obtained in Examples 5-6 and Comparative Examples 1-4 were cross-linked at 190℃ for 20 min. Afterwards, the performance of each component sample was tested. The tensile strength and elongation at break of each component sample were tested according to GB / T 1040.1-2018. The hot air accelerated aging test was conducted on each component sample according to GB / T 3512-2014, with accelerated aging at 135±2℃ for 168 h. The tensile strength and elongation at break of each component sample were then tested after aging. The tensile strength retention rate was obtained by dividing the aging tensile strength by the aging tensile strength, and the elongation at break retention rate was obtained by dividing the aging elongation at break by the aging elongation at break. The oxygen limiting index of each component sample was tested according to GB / T 2406.2-2009. The test results are shown in Table 1.

[0088] Table 1

[0089] project Tensile strength / MPa Tensile strength retention rate / % Elongation at break / % Elongation at break retention rate / % Limiting oxygen index / % Example 1 18.2 87 280 82 30.1 Example 2 17.8 88 273 83 30.7 Example 3 19.3 89 272 85 31.2 Example 4 18.7 89 264 86 31.9 Example 5 20.2 90 257 87 32.4 Example 6 19.4 91 251 87 33.2 Comparative Example 1 14.4 71 320 49 33.1 Comparative Example 2 14.1 70 311 47 33.8 Comparative Example 3 21.4 80 224 67 31.4 Comparative Example 4 20.8 81 217 63 32.0

[0090] As can be seen from Table 1, the heat-repairing modifier with plasticizing function of the present invention can ensure that the PVC cable has good processing performance before the crosslinking stage. The oxygen limiting index of each component sample is above 30%. After the crosslinking stage, the heat-repairing modifier of the present invention can also ensure that the PVC cable has good tensile properties and elongation at break. When heat-resistant, it can improve the aging resistance of the PVC cable by continuously breaking and recombining disulfide bonds.

[0091] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention, including the best mode, and also to enable any person skilled in the art to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing a flame-retardant cross-linked cable material for charging pile cables, characterized in that, Includes the following steps: The first step involves esterifying 4-chloromethyl phthalic acid with 2-ethyl-5-hexen-1-ol to obtain a reactive plasticizer. The second step involves reacting the reactive plasticizer with sodium disulfide via a nucleophilic substitution reaction to obtain a heat-repairing modifier with plasticizing function. The third step involves mixing polyvinyl chloride, flame retardant, initiator, crosslinking agent, lubricant, stabilizer, antioxidant, and heat-repairing modifier with plasticizing function, and then melting and extruding the mixture through a twin-screw extruder to obtain flame-retardant crosslinked cable material.

2. The method for preparing a flame-retardant cross-linked cable material for charging pile cables according to claim 1, characterized in that, The flame retardant is at least one of aluminum hydroxide and magnesium hydroxide.

3. The method for preparing a flame-retardant cross-linked cable material for charging pile cables according to claim 1, characterized in that, The initiator is at least one of dicumyl peroxide and bis(tert-butylperoxyisopropyl)benzene.

4. The method for preparing a flame-retardant cross-linked cable material for charging pile cables according to claim 1, characterized in that, The crosslinking agent is triallyl isocyanurate.

5. The method for preparing a flame-retardant cross-linked cable material for charging pile cables according to claim 1, characterized in that, The lubricant is at least one of calcium stearate and polyethylene wax.

6. The method for preparing a flame-retardant cross-linked cable material for charging pile cables according to claim 1, characterized in that, The stabilizer is a calcium-zinc stabilizer.

7. The method for preparing a flame-retardant cross-linked cable material for charging pile cables according to claim 1, characterized in that, Furthermore, the antioxidant is at least one of antioxidant 1010, antioxidant 1076, and antioxidant 168.

8. The method for preparing a flame-retardant cross-linked cable material for charging pile cables according to claim 1, characterized in that, The temperature of the melt extrusion is 150–160°C.

9. The method for preparing a flame-retardant cross-linked cable material for charging pile cables according to claim 1, characterized in that, The mass ratio of polyvinyl chloride, flame retardant, initiator, crosslinking agent, lubricant, stabilizer, antioxidant, and heat-repairing modifier with plasticizing function is 100:40~60:2~4:1~2:0.5~2:3~6:0.3~1:20~30.

10. The flame-retardant cross-linked cable material for charging pile cables obtained by the preparation method of claim 1.