Temperature-resistant cable material and new energy charging cable

Abstract

This invention discloses a high-temperature resistant cable material and a new energy charging cable, belonging to the field of polymer materials. It comprises the following components by weight: 30-50 parts of maleic anhydride-grafted styrene-ethylene-butene-styrene copolymer, 15-40 parts of maleic anhydride-grafted copolymer polypropylene, 0.5-2 parts of melamine borate, 0.1-3 parts of filler, 5-15 parts of naphthenic oil, 10-30 parts of flame retardant, 1-5 parts of zinc borate, and 0.1-3 parts of antioxidant. This invention uses maleic anhydride-grafted polypropylene and maleic anhydride-grafted styrene-ethylene-butene-styrene copolymer as base materials, forming a continuous phase with melamine borate, effectively improving system compatibility, reducing the amount of naphthenic oil, and improving the performance of the cable material. It solves the problems of poor mechanical properties and poor temperature resistance in existing technologies caused by the high modulus, poor flexibility, and poor aging resistance of conventional polypropylene, and has the potential to be applied to the preparation of new energy fast charging cables.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to a heat-resistant cable material and a new energy charging cable. Background Technology

[0002] New energy charging cables are responsible for power transmission and signal control, and typically need to maintain stable operation for extended periods under high voltage and high current conditions. Therefore, high requirements are placed on the mechanical properties, flame retardancy, insulation properties, and temperature resistance of the cable materials.

[0003] Cable materials, namely the materials used for cable insulation and sheathing, mainly include natural rubber, polyvinyl chloride, synthetic rubber, polyethylene, and polypropylene. However, traditional cable materials generally suffer from poor temperature resistance. In actual use, high temperatures soften the cable insulation sheath, reducing its mechanical strength. Simultaneously, repeated charging and discharging cause temperature cycling, leading to thermal fatigue and thus affecting cable lifespan.

[0004] Polypropylene (PP) is considered a highly promising recyclable high-voltage DC cable insulation material. Among its components, thermoplastic insulation materials have attracted significant attention due to their high-temperature stability and excellent recyclability. Compared to traditional cross-linked polyethylene insulation materials, polypropylene not only has a higher operating temperature but also offers advantages such as simpler manufacturing processes and lower costs. However, conventional polypropylene suffers from high modulus, poor flexibility, and poor aging resistance. Therefore, while cables made directly from it may be slightly superior to those made from traditional cable materials, they still exhibit poor mechanical properties and temperature resistance. Thus, a high-temperature resistant cable material is urgently needed to address these issues in the production of new energy charging cables. Summary of the Invention

[0005] Therefore, the present invention provides a heat-resistant cable material and a new energy charging cable to solve the problems of poor mechanical properties and poor temperature resistance of cables in the prior art due to the high modulus, poor flexibility, and poor aging resistance of conventional polypropylene.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] According to a first aspect of the present invention, a heat-resistant cable material is provided, comprising the following components in parts by weight: 30-50 parts of maleic anhydride-grafted styrene-ethylene-butene-styrene copolymer, 15-40 parts of maleic anhydride-grafted copolymer polypropylene, 0.5-2 parts of melamine borate, 0.1-3 parts of filler, 5-15 parts of naphthenic oil, 10-30 parts of flame retardant, 1-5 parts of zinc borate, and 0.1-3 parts of antioxidant.

[0008] Preferably, the composition comprises the following components in parts by weight: 41 parts maleic anhydride-grafted styrene-ethylene-butene-styrene copolymer, 23 parts maleic anhydride-grafted copolymer polypropylene, 1 part melamine borate, 1 part filler, 10 parts naphthenic oil, 20 parts flame retardant, 3 parts zinc borate, and 1 part antioxidant.

[0009] Furthermore, the maleic anhydride-grafted copolymer polypropylene has a melt index of 5.0 g / 10 min and a density of 0.9 g / cm³. 3 The Shore hardness is 63D; the grafting rate of the maleic anhydride-grafted styrene-ethylene-butene-styrene copolymer is 1.7%, and the Shore hardness is 71A.

[0010] Preferably, the filler is a silicone masterbatch, the antioxidant is one or more of antioxidant 1010, antioxidant 168 or antioxidant DLTP, and the flame retardant is melamine cyanurate.

[0011] According to a second aspect of the present invention, a method for preparing a heat-resistant cable material is provided, which specifically includes the following steps:

[0012] S1. Maleic anhydride-grafted styrene-ethylene-butene-styrene copolymer, maleic anhydride-grafted copolymer polypropylene, and naphthenic oil are mixed in a mixer at 50-100 rpm and 120°C for 30 min.

[0013] S2. Add flame retardant, zinc borate, antioxidant, filler and melamine borate, and continue stirring;

[0014] S3. After mixing, the mixture is processed by a twin-screw extruder, cooled, pelletized, and dried to obtain heat-resistant cable material.

[0015] Furthermore, in step S2, the stirring rate is 100-300 rpm, the temperature is 80°C, and the time is 3-5 min.

[0016] Further, the parameters for processing the twin-screw extruder in step S3 are set as follows: the length-to-diameter ratio of the twin screws is 48:1; the twin screw temperatures are: 150-160℃ in zone 1, 160-170℃ in zone 2, 170-180℃ in zone 3, 170-180℃ in zone 4, 170-180℃ in zone 5, 170-180℃ at the die head, and 200-300 rpm.

[0017] According to a third aspect of the present invention, a new energy charging cable is provided, comprising a core, an insulation layer, a shielding layer, and a sheath layer, wherein the sheath layer is prepared from the aforementioned heat-resistant cable material.

[0018] Furthermore, the method for preparing the sheath layer is as follows: heat-resistant cable material is wrapped onto the cable semi-finished product through a single-screw cable extruder, and then passed through a heat-insulated shaping pipe with a length of 10-20m and a temperature of 150-180℃. The cable traction speed is 10m / min. After the cable leaves the pipe, it immediately enters a water tank at 15-25℃ for cooling. After cooling, the cable sheath layer is obtained.

[0019] Furthermore, the parameters for the heat-resistant cable material coating are: Zone 1 160-170℃, Zone 2 170-180℃, Zone 3 180-190℃, Zone 4 180-190℃, and head section 170-180℃.

[0020] The present invention has the following advantages:

[0021] 1. This invention forms a continuous phase by grafting maleic anhydride onto styrene-ethylene-butene-styrene copolymer (SEBS-g-MA), maleic anhydride onto copolymer polypropylene (MA-g-PP), and melamine borate (MB) in a specific ratio. Combined with an optimized preparation process, this allows the cable material to maintain good mechanical and physical properties even at high temperatures. At the same time, using maleic anhydride-grafted polymers as base materials effectively improves the compatibility of the system, reduces the amount of naphthenic oil used, and enhances the performance of the cable material.

[0022] 2. Melamine cyanurate (MCA) is used as a flame retardant and zinc borate as a synergist. Melamine borate is added to the base material crosslinking system to fundamentally improve the flame retardancy and temperature resistance of the system. At the same time, zinc borate as a synergist can effectively reduce the amount of melamine cyanurate added and improve the system compatibility.

[0023] 3. The addition of silicone masterbatch filler to the system improves the fluidity of the system while maintaining good flexibility and impact resistance. The resulting sheath layer is not only temperature resistant and flame retardant, but also has good electrical insulation and environmental adaptability, making it suitable for high-end application scenarios such as charging cables for new energy vehicles. Detailed Implementation

[0024] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] According to a first aspect of the present invention, a heat-resistant cable material is provided, comprising the following components in parts by weight: 30-50 parts of maleic anhydride-grafted styrene-ethylene-butene-styrene copolymer, 15-40 parts of maleic anhydride-grafted copolymer polypropylene, 0.5-2 parts of melamine borate, 0.1-3 parts of filler, 5-15 parts of naphthenic oil, 10-30 parts of flame retardant, 1-5 parts of zinc borate, and 0.1-3 parts of antioxidant.

[0026] The product comprises the following components by weight: 41 parts maleic anhydride-grafted styrene-ethylene-butene-styrene copolymer, 23 parts maleic anhydride-grafted copolymer polypropylene, 1 part melamine borate, 1 part filler, 10 parts naphthenic oil, 20 parts flame retardant, 3 parts zinc borate, and 1 part antioxidant.

[0027] The melt flow index of the maleic anhydride-grafted copolymer polypropylene is 5.0 g / 10 min, and the density is 0.9 g / cm³. 3 The Shore hardness is 63D; the grafting rate of maleic anhydride-grafted styrene-ethylene-butene-styrene copolymer is 1.7%, and the Shore hardness is 71A.

[0028] The filler is a silicone masterbatch, the antioxidant is one or more of antioxidant 1010, antioxidant 168 or antioxidant DLTP, and the flame retardant is melamine cyanurate.

[0029] According to a second aspect of the present invention, a method for preparing a heat-resistant cable material is provided, which specifically includes the following steps:

[0030] S1. Maleic anhydride-grafted styrene-ethylene-butene-styrene copolymer, maleic anhydride-grafted copolymer polypropylene and naphthenic oil are mixed in a mixer at 50-100 rpm and 120℃ for 30 min.

[0031] S2. Add flame retardant, zinc borate, antioxidant, filler and melamine borate, and continue stirring;

[0032] S3. After mixing, the mixture is processed by a twin-screw extruder, cooled, pelletized, and dried to obtain heat-resistant cable material.

[0033] In step S2, the stirring rate is 100-300 rpm, the temperature is 80℃, and the time is 3-5 min.

[0034] In step S3, the parameters for processing the twin-screw extruder are set as follows: the length-to-diameter ratio of the twin screws is 48:1; the twin screw temperatures are: zone 1 150-160℃, zone 2 160-170℃, zone 3 170-180℃, zone 4 170-180℃, zone 5 170-180℃, die head 170-180℃, and screw speed 200-300 rpm.

[0035] According to a third aspect of the present invention, a new energy charging cable is provided, comprising a core, an insulation layer, a shielding layer, and a sheath layer, wherein the sheath layer is prepared from the aforementioned heat-resistant cable material.

[0036] The preparation method of the sheath layer is as follows: heat-resistant cable material is wrapped on the cable semi-finished product through a single screw cable extruder, and then passed through a heat-insulated shaping pipe with a length of 10-20m and a temperature of 150-180℃. The cable traction speed is 10m / min. After the cable leaves the pipe, it immediately enters a water tank at 15-25℃ for cooling. After cooling, the cable sheath layer is obtained.

[0037] The parameters for the heat-resistant cable material coating are: Zone 1 160-170℃, Zone 2 170-180℃, Zone 3 180-190℃, Zone 4 180-190℃, and head section 170-180℃.

[0038] To better illustrate the inventiveness of the present invention, the following embodiments and comparative examples are provided, and a new energy charging cable sheath layer based on cable material is provided.

[0039] Example 1

[0040] S1. Place 4.1 kg of maleic anhydride-grafted styrene-ethylene-butene-styrene copolymer (purchased from Mitsui Chemicals, Japan), 2.3 kg of maleic anhydride-grafted copolymer polypropylene (purchased from Kraton Polymers, USA) and 1 kg of naphthenic oil in a mixer and stir at 75 rpm and 120°C for 30 min.

[0041] S2. Add 2 kg of melamine cyanurate (purchased from Guangzhou Yinyuan New Material Co., Ltd.), 0.3 kg of zinc borate, 0.1 kg of antioxidant 1010, 0.1 kg of silicone masterbatch and 0.1 kg of melamine borate (purchased from Shandong Lifan Chemical Co., Ltd.), and stir for 5 min at 200 rpm and 80°C.

[0042] S3. After mixing, the mixture is processed through a twin-screw extruder with a length-to-diameter ratio of 48:1. The twin-screw temperatures are set as follows: Zone 1 150-160℃, Zone 2 160-170℃, Zone 3 170-180℃, Zone 4 170-180℃, Zone 5 170-180℃, Die head 170-180℃, and screw speed 200-300 rpm. After cooling, the mixture is pelletized and dried to obtain heat-resistant cable material.

[0043] S4. Set the parameters of the single-screw cable extruder as follows: Zone 1 160-170℃, Zone 2 170-180℃, Zone 3 180-190℃, Zone 4 180-190℃, and die head 170-180℃. Wrap the heat-resistant cable material on the cable semi-finished product, and then pass it through a 20m long heat-insulating and shaping pipe with a temperature of 150-180℃. The cable pulling speed is 10m / min. After the cable leaves the pipe, it immediately enters a water tank at 15-25℃ for cooling. After cooling, the cable sheath layer is obtained.

[0044] Example 2

[0045] This embodiment is based on Example 1, except that the mass of each component is as follows: 4.9 kg maleic anhydride-grafted styrene-ethylene-butene-styrene copolymer, 1.5 kg maleic anhydride-grafted copolymer polypropylene, 0.1 kg melamine borate, 0.1 kg silicone masterbatch, 1 kg naphthenic oil, 2 kg melamine cyanurate, 0.3 kg zinc borate, and 0.1 kg antioxidant 1010. The other specific processing parameters are the same as in Example 1.

[0046] Example 3

[0047] This embodiment is based on Example 1, except that the mass of each component is as follows: 3 kg maleic anhydride-grafted styrene-ethylene-butene-styrene copolymer, 3.4 kg maleic anhydride-grafted copolymer polypropylene, 0.1 kg melamine borate, 0.1 kg silicone masterbatch, 1 kg naphthenic oil, 2 kg melamine cyanurate, 0.3 kg zinc borate, and 0.1 kg antioxidant 1010. The other specific processing parameters are the same as in Example 1.

[0048] Example 4

[0049] This embodiment is based on Example 1, except that the mass of each component is as follows: 4 kg maleic anhydride-grafted styrene-ethylene-butene-styrene copolymer, 2.3 kg maleic anhydride-grafted copolymer polypropylene, 0.2 kg melamine borate, 0.1 kg silicone masterbatch, 1 kg naphthenic oil, 2 kg melamine cyanurate, 0.3 kg zinc borate, and 0.1 kg antioxidant 1010. The other specific processing parameters are the same as in Example 1.

[0050] Example 5

[0051] This embodiment is based on Example 1, except that the mass of each component is as follows: 3.6 kg maleic anhydride-grafted styrene-ethylene-butene-styrene copolymer, 1.8 kg maleic anhydride-grafted copolymer polypropylene, 0.1 kg melamine borate, 0.1 kg silicone masterbatch, 1 kg naphthenic oil, 3 kg melamine cyanurate, 0.3 kg zinc borate, and 0.1 kg antioxidant 1010. The other specific processing parameters are the same as in Example 1.

[0052] Example 6

[0053] This embodiment is based on Example 1, except that the mass of each component is as follows: 4.6 kg maleic anhydride-grafted styrene-ethylene-butene-styrene copolymer, 2.8 kg maleic anhydride-grafted copolymer polypropylene, 0.1 kg melamine borate, 0.1 kg silicone masterbatch, 1 kg naphthenic oil, 1 kg melamine cyanurate, 0.3 kg zinc borate, and 0.1 kg antioxidant 1010. The other specific processing parameters are the same as in Example 1.

[0054] Comparative Example 1

[0055] This comparative example is based on Example 1, except that the mass of each component is as follows: 4.1 kg maleic anhydride-grafted styrene-ethylene-butene-styrene copolymer, 2.3 kg maleic anhydride-grafted copolymer polypropylene, 0.1 kg melamine borate, 0.1 kg silicone masterbatch, 1 kg cycloalkane oil, 2 kg melamine cyanurate, and 0.1 kg antioxidant 1010. That is, zinc borate is not added. The other specific processing parameters are the same as in Example 1.

[0056] Comparative Example 2

[0057] This comparative example is based on Example 1, except that the mass of each component is: 4.1 kg maleic anhydride-grafted styrene-ethylene-butene-styrene copolymer, 2.3 kg maleic anhydride-grafted copolymer polypropylene, 0.1 kg melamine borate, 0.1 kg silicone masterbatch, 2 kg melamine cyanurate, 0.3 kg zinc borate, and 0.1 kg antioxidant 1010. That is, no naphthenic oil is added, and the other specific processing parameters are the same as in Example 1.

[0058] Comparative Example 3

[0059] This comparative example is based on Example 1, except that the mass of each component is as follows: 4.1 kg maleic anhydride-grafted styrene-ethylene-butene-styrene copolymer, 2.3 kg maleic anhydride-grafted copolymer polypropylene, 0.1 kg silicone masterbatch, 1 kg naphthenic oil, 2 kg melamine cyanurate, 0.3 kg zinc borate, and 0.1 kg antioxidant 1010, i.e., no melamine borate is added. The other specific processing parameters are the same as in Example 1.

[0060] Comparative Example 4

[0061] This comparative example is based on Example 1, except that the mass of each component is: 4.1 kg maleic anhydride-grafted styrene-ethylene-butene-styrene copolymer, 0.1 kg melamine borate, 0.1 kg silicone masterbatch, 1 kg naphthenic oil, 2 kg melamine cyanurate, 0.3 kg zinc borate, and 0.1 kg antioxidant 1010. That is, maleic anhydride-grafted copolymer polypropylene is not added. The other specific processing parameters are the same as in Example 1.

[0062] Comparative Example 5

[0063] This comparative example is based on Example 1, except that the mass of each component is: 2.3 kg maleic anhydride-grafted copolymer polypropylene, 0.1 kg melamine borate, 0.1 kg silicone masterbatch, 1 kg naphthenic oil, 2 kg melamine cyanurate, 0.3 kg zinc borate, and 0.1 kg antioxidant 1010. That is, maleic anhydride-grafted styrene-ethylene-butene-styrene copolymer is not added. The other specific processing parameters are the same as in Example 1.

[0064] Comparative Example 6

[0065] This embodiment is based on Example 1, except that the mass of each component is: 4.1 kg maleic anhydride-grafted styrene-ethylene-butene-styrene copolymer, 2.3 kg maleic anhydride-grafted copolymer polypropylene, 0.1 kg melamine borate, 0.1 kg silicone masterbatch, 1 kg naphthenic oil, 0.3 kg zinc borate, and 0.1 kg antioxidant 1010, i.e., no melamine cyanurate is added. The other specific processing parameters are the same as in Example 1.

[0066] Test Example 1

[0067] The tensile properties of the sheath layer of new energy charging cables were determined according to the method of GB / T1040.1-2025. The tensile strength and elongation at break of the sheath layer are shown in Table 1.

[0068] Table 1 Tensile strength and elongation at break of the sheath layer

[0069] It can be seen that the complete component groups of the examples exhibit better tensile strength and elongation at break than the comparative examples; among them, Example 1 showed the highest tensile strength, reaching 18.6 MPa, and an elongation at break of 520.4%. Compared with Example 1, the tensile strength of Comparative Examples 1-6 decreased by 33.9%, 54.3%, 45.7%, 50.5%, 58.1%, and 47.3%, respectively, and the elongation at break decreased by 37.8%, 63.5%, 51.5%, 59.5%, 69.3%, and 45.9%, respectively. This indicates that a suitable component ratio is crucial for the high-temperature resistant cable material and its prepared sheath layer to achieve good mechanical properties. Meanwhile, the tensile strength and elongation at break of Comparative Examples 1-6, which lacked a single component, were significantly lower than those of the complete example groups. In particular, Comparative Example 2, which did not add naphthenic oil, had a tensile strength of only 8.5 MPa and an elongation at break of only 189.7%. Comparative Example 5, which lacked maleic anhydride-grafted styrene-ethylene-butene-styrene copolymer, had a tensile strength of only 7.8 MPa and an elongation at break of only 160.0%. This indicates that maleic anhydride-grafted styrene-ethylene-butene-styrene copolymer and naphthenic oil are important components contributing to the mechanical strength of this system. Among them, maleic anhydride-grafted styrene-ethylene-butene-styrene copolymer is an important base material; naphthenic oil can improve the dispersibility of fillers in the system, eliminate internal stress, and reduce microcracks, system agglomeration, and interfacial voids after molding. Therefore, the absence of these two components leads to the collapse of the system's mechanical properties. The tensile strengths of Comparative Examples 1, 3, 4, and 6, which lacked zinc borate, melamine borate, maleic anhydride-grafted copolymer polypropylene, and melamine cyanurate, were 12.3 MPa, 10.1 MPa, 9.2 MPa, and 9.8 MPa, respectively, with elongations at break of 320.7%, 250.5%, 210.8%, and 281.6%, respectively, significantly lower than those of the Example Group. This is because the absence of zinc borate leads to the failure of interfacial bridging in the system; the absence of melamine borate causes the disappearance of the continuous phase formed by the two base materials (SEBS-g-MA and MA-g-PP) in the system, weakening interfacial compatibility and resulting in a decrease in mechanical properties; the absence of MA-g-PP in Comparative Example 4 results in the lack of a hard phase in the system, thus significantly reducing mechanical strength; and melamine cyanurate, in this system, not only acts as a flame retardant but also serves as a nucleating agent and interfacial reinforcing agent to some extent, therefore its absence leads to a slight decrease in mechanical strength.

[0070] Test Example 2

[0071] The mechanical properties of the cable sheath layer after hot air aging and low temperature treatment were determined according to GB / T 2951.12-2008 and GB / T 2951.14-2008, respectively, to evaluate its temperature resistance. The specific results are shown in Table 2.

[0072] Table 2. Retention rate of tensile strength and elongation at break of the sheath layer after high-temperature aging and low-temperature treatment.

[0073] As shown in Table 2, the tensile strength retention and elongation at break of the Example Group after high-temperature and low-temperature treatments were significantly better than those of the Comparative Example Group, both exceeding 80%, indicating that the cable sheath prepared based on the complete components of the present invention has excellent temperature resistance. Among them, Example 1 showed the best temperature resistance, with tensile strength retention and elongation at break exceeding 88% after both high-temperature and low-temperature treatments. Compared with Example 1, which had the best temperature resistance, the retention rates of tensile strength and elongation at break of Comparative Examples 2 and 3 after high- and low-temperature treatments were significantly reduced, indicating that the wide temperature stability of the temperature-resistant cable material prepared by the present invention depends on the synergistic effect of each component. Comparative Example 1, which lacked zinc borate, showed the best temperature resistance among the comparative examples, indicating that zinc borate is only an auxiliary component rather than a core component for the temperature resistance of the system. Comparative Examples 4 and 5, which lack both base materials, showed only about 50% retention of tensile strength and elongation at break after high-temperature aging and low-temperature treatment, indicating that the synergistic effect of the two base materials helps to improve the temperature resistance of the system. Among them, Comparative Example 5 showed the lowest temperature resistance, indicating that maleic anhydride-grafted styrene-ethylene-butene-styrene copolymer is one of the core components for the wide temperature stability of this temperature-resistant cable material.

[0074] Test Example 3

[0075] Breakdown strength test:

[0076] Five 50mm × 50mm × 2mm samples were cut for each embodiment and fixed between the electrodes, ensuring the electrodes were aligned with the center of the sample. The voltage was increased uniformly at a rate of 1kV / s until the sample broke down, and the breakdown voltage value was recorded. Three different points were tested on each sample, and the average value was taken. The breakdown strength was calculated using the formula... Calculate; where E U represents the breakdown strength, U represents the breakdown voltage, and d represents the sample thickness. The breakdown strength of the charging cable sheath layer prepared from the heat-resistant cable material is shown in Table 3.

[0077] Table 3. Breakdown strength of charging cable sheath layers prepared from heat-resistant cable materials

[0078] As can be seen, the example groups exhibited good insulation performance, with breakdown strengths all exceeding 28 kV / mm. In contrast, the comparative example groups lacking certain components had an average breakdown strength of 23.63 kV / mm. Comparative Example 5 showed the lowest breakdown strength at only 19.5 kV / mm, failing to meet the ≥20 kV / mm requirement for typical cable sheath materials, indicating that SEBS-g-MA is the core insulation component in the cable material system. This may be because SEBS-g-MA has better flexibility, while MA-g-PP is relatively more rigid; brittle materials are more prone to electrical breakdown, reducing the system's insulation capacity. Comparative Example 1 showed the highest breakdown strength among the comparative example groups, indicating that zinc borate only serves as an auxiliary component for the system's insulation performance. Compared with Example 1, the breakdown strength of Comparative Examples 2, 3, 4, and 6 decreased by 40.5%, 27.2%, 31.1%, and 28.7%, respectively. This may be because the absence of naphthenic oil in the system reduces the system compatibility, leading to filler agglomeration and the formation of a large number of undispersed particles, which significantly reduces the breakdown strength. The absence of melamine borate prevents SEBS-g-MA and MA-g-PP from forming a continuous phase, deteriorating interfacial compatibility, forming more microphase separation regions, reducing the density of the cable material, and thus affecting insulation. The absence of MA-g-PP leaves only the soft SEBS-g-MA elastomer in the system, which cannot form a rigid skeleton, making the molecular chains more mobile and more prone to electron collision ionization. The absence of melamine cyanurate causes the system to lose its interfacial reinforcing agent, resulting in an imperfect crystalline structure of the material, thereby reducing the insulation of the material. The results above show that the insulation performance of the heat-resistant cable material prepared by the present invention and the charging cable prepared based thereon depends on the continuous phase formed by SEBS-g-MA, MA-g-PP and melamine borate, as well as the synergistic effect of each component.

[0079] Test Example 4

[0080] The flame retardancy of the charging cable sheath layer prepared from the heat-resistant cable material was tested by the limiting index oxygen test method, specifically referring to GB / T 2406.2-2009, and the results are shown in Table 4.

[0081] Table 4 Flame retardancy of charging cable sheaths made from heat-resistant cable materials

[0082] As shown in Table 4, the limiting oxygen index (LOI) of Examples 1-6 is higher than 30%. Generally, an LIO above 27% is considered flame-retardant, while the minimum requirement for flame-retardant cables is 30%. This indicates that the heat-resistant cable material prepared by this invention has good flame retardancy and meets industry standards. Among them, Example 5 has the highest LIO at 33.1%, followed by Example 1 at 32.8%, indicating that the flame retardant in Example 1 may have reached saturation, and further addition of flame retardant did not significantly improve the flame-retardant performance of the cable material. In contrast, Example 6 exhibits the lowest LIO among the example groups, while Comparative Example 6 exhibits the lowest LIO among all groups, at 30.3% and 22.3% respectively, indicating that the flame retardant melamine cyanurate is the core component for the flame-retardant performance of the heat-resistant cable material prepared by this invention. The limiting oxygen index (LOI) of Comparative Example 1 was the highest among the comparative examples, indicating that zinc borate only acts as an enhancer of flame retardant performance. Adding a small amount can improve the flame retardant properties of the system, but it is not a core component that performs the function. Its main role is to improve the flame retardant performance of the system while limiting the amount of melamine cyanurate flame retardant, thus improving system compatibility. Compared with Example 1, the LIOs of Comparative Examples 2-5 decreased by 19.2%, 15.9%, 18.0%, and 21.3%, respectively, all falling within the category of combustible materials. The reason may be that although naphthenic oil is flammable, it improves the compatibility of the system, reduces voids and cracks in the material, and reduces the contact between flammable organic matter and oxygen, thus affecting the flame retardant performance of the material; melamine borate itself, as a nitrogen-boron flame retardant, can synergistically retard flame with zinc borate and melamine cyanurate, and can also synergistically form a continuous phase with SEBS-g-MA and MA-g-PP, improving the compatibility of the system and thus improving the flame retardant performance; SEBS-g-MA and MA-g-PP themselves are flammable organic matter, and the system cannot effectively form a continuous phase without either phase, and cannot effectively form a carbon layer during combustion, making the cable material easier to burn.

[0083] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A heat-resistant cable material, characterized in that, It includes the following components by weight: 30-50 parts of maleic anhydride-grafted styrene-ethylene-butene-styrene copolymer, 15-40 parts of maleic anhydride-grafted copolymer polypropylene, 0.5-2 parts of melamine borate, 0.1-3 parts of filler, 5-15 parts of naphthenic oil, 10-30 parts of flame retardant, 1-5 parts of zinc borate, and 0.1-3 parts of antioxidant.

2. The heat-resistant cable material as described in claim 1, characterized in that, The product comprises the following components by weight: 41 parts maleic anhydride-grafted styrene-ethylene-butene-styrene copolymer, 23 parts maleic anhydride-grafted copolymer polypropylene, 1 part melamine borate, 1 part filler, 10 parts naphthenic oil, 20 parts flame retardant, 3 parts zinc borate, and 1 part antioxidant.

3. The heat-resistant cable material as described in claim 1, characterized in that, The maleic anhydride-grafted copolymer polypropylene has a melt flow index of 5.0 g / 10 min and a density of 0.9 g / cm³. 3 The Shore hardness is 63D; the grafting rate of the maleic anhydride-grafted styrene-ethylene-butene-styrene copolymer is 1.7%, and the Shore hardness is 71A.

4. The heat-resistant cable material as described in claim 1, characterized in that, The filler is a silicone masterbatch, the antioxidant is one or more of antioxidant 1010, antioxidant 168 or antioxidant DLTP, and the flame retardant is melamine cyanurate.

5. A method for preparing a heat-resistant cable material, used to prepare the heat-resistant cable material according to any one of claims 1-4, characterized in that, Specifically, the following steps are included: S1. Maleic anhydride-grafted styrene-ethylene-butene-styrene copolymer, maleic anhydride-grafted copolymer polypropylene and naphthenic oil are mixed in a mixer at 50-100 rpm and 120℃ for 30 min. S2. Add flame retardant, zinc borate, antioxidant, filler and melamine borate, and continue stirring; S3. After mixing, the mixture is processed by a twin-screw extruder, cooled, pelletized, and dried to obtain heat-resistant cable material.

6. The method for preparing the heat-resistant cable material as described in claim 5, characterized in that, The stirring speed in step S2 is 100-300 rpm, the temperature is 80℃, and the time is 3-5 min.

7. The method for preparing the heat-resistant cable material as described in claim 5, characterized in that, The parameters for processing the twin-screw extruder in step S3 are set as follows: the length-to-diameter ratio of the twin screws is 48:1; the twin screw temperatures are: zone 1 150-160℃, zone 2 160-170℃, zone 3 170-180℃, zone 4 170-180℃, zone 5 170-180℃, die head 170-180℃, and screw speed 200-300 rpm.

8. A new energy charging cable, characterized in that, It includes a conductor, an insulation layer, a shielding layer, and a sheath layer, wherein the sheath layer is prepared from the heat-resistant cable material according to any one of claims 1-4.

9. The new energy charging cable as described in claim 8, characterized in that, The method for preparing the sheath layer is as follows: heat-resistant cable material is wrapped onto the cable semi-finished product using a single-screw cable extruder, and then passed through a heat-insulated shaping pipe with a length of 10-20m and a temperature of 150-180℃. The cable traction speed is 10m / min. After the cable leaves the pipe, it immediately enters a water tank at 15-25℃ for cooling. After cooling, the cable sheath layer is obtained.

10. The new energy charging cable as described in claim 8, characterized in that, The parameters for the heat-resistant cable material coating are: Zone 1 160-170℃, Zone 2 170-180℃, Zone 3 180-190℃, Zone 4 180-190℃, and head section 170-180℃.

Images