Composite cable and method for manufacturing the same

Abstract

The application relates to the technical field of cables, and discloses a composite cable and a preparation method thereof, which comprises a power supply wire, a communication wire and an outer sheath, the surfaces of the power supply wire and the communication wire are covered by an inner sheath, and the outer sheath covers the power supply wire and the communication wire simultaneously; the application range of the composite cable prepared by the application is greatly widened; the heat resistance and the aging resistance of the inner sheath material and the outer sheath material of the composite cable are obviously improved by greatly improving the performance of the inner sheath material and the outer sheath material of the composite cable, so that the service life of the composite cable is improved.

Description

Technical Field

[0001] This invention relates to the field of cable technology, specifically to a composite cable. Background Technology

[0002] With the rapid development of data communication and information technology, the performance requirements for transmission cables are becoming increasingly stringent. Currently, there are composite cables that integrate signal lines and power lines. For such composite cables, effective shielding is required between the power transmitted by the power lines and the signals transmitted by the signal lines. External interference signals must also be shielded during signal transmission, while simultaneously preventing signals in the line from interfering with the external environment.

[0003] For example, prior art publication number CN 210429379 U discloses a composite cable, including: a node device, a transition component, a base cable, and an outer sheath; the two ends of the node device are connected to the transition component, which is made of a buffer material; the base cable is connected to the transition component, and the node device, transition component, and base cable form a cable body, with the outer sheath covering the outside of the cable body, and a node protection layer is provided on the outside of the node device. The transition component can act as a buffer, reducing the bending radius of the composite cable, avoiding stress concentration, and preventing the node device from being damaged by external forces; during the extrusion molding process of the composite cable, the transition component can act as a transition, preventing the node device from jamming the extrusion mold and improving manufacturing efficiency; the transition component can also act as a protector, reducing the impact of external forces on the pads of the node device, preventing the pads from detaching, and reducing the failure rate of the composite cable. However, the flame retardant and aging resistance properties of the composite cable prepared by this method are relatively average, which limits its development.

[0004] Based on this, we propose a composite cable in the hope of addressing the shortcomings of existing technologies. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] To address the shortcomings of existing technologies, this invention provides a composite cable and its preparation method.

[0007] (II) Technical Solution

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] A composite cable includes a power supply line, a communication line, and an outer sheath. The surfaces of the power supply line and the communication line are covered by the inner sheath, and the outer sheath covers both the power supply line and the communication line simultaneously.

[0010] The inner sheath material is made of the following components by weight: 70-80 parts EVA resin, 21-25 parts high-density polyethylene resin, 15-18 parts calcium carbonate, 1-2 parts flame retardant, and 6-12 parts intercalated bentonite.

[0011] The outer sheath material is made of the following components by weight: 85-90 parts EVA resin, 18-24 parts high-density polyethylene resin, 6-15 parts calcium carbonate, 3-5 parts dioctyl phthalate, 1-2 parts flame retardant, 0.5-2 parts zinc oxide, 8-12 parts modified hexagonal boron nitride particles, 1-3 parts sodium stearate, 0.3-0.8 parts N,N-methylenebisacrylamide, and 1-1.6 parts polyethylene wax.

[0012] As a further technical solution, the method for preparing the flame retardant is as follows:

[0013] Weigh the zinc salt and magnesium salt separately, then mix them together and add them to deionized water. Stir the solution to obtain a mixed solution.

[0014] Add sodium hydroxide solution dropwise to the above mixed solution while stirring. After the addition is complete, adjust the temperature to 80°C, keep it warm and stir for 2 hours, then filter, wash until neutral, dry, pulverize and grind to obtain the flame retardant.

[0015] As a further technical solution, the zinc salt is zinc sulfate, and the magnesium salt is magnesium chloride;

[0016] The zinc sulfate and magnesium chloride are mixed in a mass ratio of 1:5.

[0017] The mixed solution contains 3% zinc sulfate and 15% magnesium chloride by mass.

[0018] As a further technical solution: the mass ratio of the mixed solution to the sodium hydroxide solution is 1:1;

[0019] The concentration of the sodium hydroxide solution is 1.8 mol / L.

[0020] As a further technical solution, the method for preparing the intercalated bentonite is as follows:

[0021] Bentonite was evenly dispersed in deionized water and stirred until homogeneous. Sodium citrate was then added and stirred until homogeneous. The pH was adjusted to 10.5 and the temperature was adjusted to 75°C. The mixture was kept at this temperature to obtain a bentonite dispersion.

[0022] Ethanol was added to the bentonite dispersion and stirred until homogeneous. Then, trimethyl phosphonite and trimethylolphosphine oxide were added. The temperature was adjusted to 80°C and the mixture was stirred and kept at this temperature for 2 hours. After stirring, the mixture was filtered, washed, and dried to constant weight to obtain intercalated bentonite.

[0023] As a further technical solution, the mass ratio of bentonite, deionized water and sodium citrate is 10:50:3.

[0024] The mass ratio of the bentonite dispersion, ethanol, trimethyl phosphonite and trimethylolphosphine oxide is 35:10:3:1.

[0025] As a further technical solution: the method for preparing the modified hexagonal boron nitride particles is as follows:

[0026] Pre-modification treatment of hexagonal boron nitride particles:

[0027] Hexagonal boron nitride particles were uniformly dispersed in isopropanol solution, and then the pH was adjusted to 5.5 and the temperature was adjusted to 72℃. The mixture was kept warm and stirred for 30 min. Then, silane coupling agent solution was added and the mixture was stirred for 1 hour. The mixture was then filtered, washed, and dried to obtain pre-modified hexagonal boron nitride particles.

[0028] Pre-modified hexagonal boron nitride particles and polyvinyl chloride resin were mixed in a 3:2 mass ratio and added to a twin-screw extruder for melt extrusion to obtain composite particles.

[0029] The composite particles obtained above were added to an ultrasonic pulverizer and ultrasonically pulverized for 15 minutes to obtain modified hexagonal boron nitride particles.

[0030] As a further technical solution: the mass ratio of the hexagonal boron nitride particles to the isopropanol solution is 1:12;

[0031] The isopropanol solution has a mass fraction of 20%.

[0032] The silane coupling agent solution and isopropanol solution are mixed in a mass ratio of 1:10, and the silane coupling agent solution has a mass fraction of 7.5%.

[0033] The ultrasonic pulverizer has a power of 300W.

[0034] A method for preparing a composite cable includes the following steps:

[0035] (1) EVA resin, high-density polyethylene resin, calcium carbonate, flame retardant and intercalated bentonite are heated in a reactor at a temperature of 500°C for 2 hours until they are heated to become molten fluid materials.

[0036] (2) Place the required metal wires of the power supply line and communication line into the mold in sequence, extrude the molten fluid material into the mold through the extruder, and then perform cooling annealing on the mold. The cooling temperature is 55℃ and the duration is 1h to form the inner sheath.

[0037] (3) Place the wrapped power supply line and communication line together, heat and melt the outer sheath material with an injection molding machine, and then evenly attach it to the outer surface of the power supply line and communication line. After cooling and shaping, the outer sheath is formed.

[0038] By introducing intercalated bentonite, the inner sheath material has a higher melt crystallization temperature. Its introduction can positively promote the aggregation behavior and dispersion state of the particles inside the material. The modification treatment of the intercalation method of bentonite can cause changes in the surface chemical properties of the particles, thereby improving its reinforcing effect and significantly improving the mechanical properties.

[0039] The introduction of modified hexagonal boron nitride reduces the size of the filler aggregates, allowing particle clusters to be distributed in the continuous phase of the matrix material with a smaller volume. Simultaneously, the interaction between inorganic particles is significantly weakened, resulting in a marked improvement in the filler's dispersion performance. Furthermore, the increased specific surface area leads to a significant increase in surface energy. In the composite system, the modified hexagonal boron nitride dispersed phase is provided with more heterogeneous nucleation sites by the chemical network molecular chain segments, thereby increasing the nucleation rate of EVA and significantly improving the performance of the outer sheath material, particularly its thermal stability and volume resistivity.

[0040] EVA molecular chains can be more easily adsorbed onto the surface of modified hexagonal boron nitride, and the interfacial adhesion between polymer molecules and modified hexagonal boron nitride particles is significantly enhanced, forming a relatively dense polymer-filler network. This allows the polymer molecular chains to be fixed to the surface of inorganic particles, making it difficult for them to loosen. As a result, the thermal stability of the material is greatly improved.

[0041] (III) Beneficial Effects

[0042] Compared with the prior art, the present invention provides a composite cable with the following advantages:

[0043] The application range of the composite cable prepared by this invention has been greatly expanded. By significantly improving the performance of the inner and outer sheath materials of the composite cable, this invention significantly improves the heat resistance and aging resistance of the inner and outer sheath materials, thereby increasing their service life. Attached Figure Description

[0044] Figure 1 A graph showing the effect of different amounts of intercalated bentonite on the flame retardant properties of the inner sheath material;

[0045] Figure 2 The graph shows the effect of different amounts of modified hexagonal boron nitride on the tensile properties of the outer sheath. Detailed Implementation

[0046] 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.

[0047] The following are specific examples:

[0048] Example 1

[0049] A composite cable includes a power supply line, a communication line, and an outer sheath. The surfaces of the power supply line and the communication line are covered by the inner sheath, and the outer sheath covers both the power supply line and the communication line simultaneously.

[0050] The inner sheath material is made of the following components by weight: 70 parts EVA resin, 21 parts high-density polyethylene resin, 15 parts calcium carbonate, 1 part flame retardant, and 6 parts intercalated bentonite.

[0051] The outer sheath material is made of the following components by weight: 85 parts EVA resin, 18 parts high-density polyethylene resin, 6 parts calcium carbonate, 3 parts dioctyl phthalate, 1 part flame retardant, 0.5 parts zinc oxide, 8 parts modified hexagonal boron nitride particles, 1 part sodium stearate, 0.3 parts N,N-methylenebisacrylamide, and 1 part polyethylene wax.

[0052] As a further technical solution, the method for preparing the flame retardant is as follows:

[0053] Weigh the zinc salt and magnesium salt separately, then mix them together and add them to deionized water. Stir the solution to obtain a mixed solution.

[0054] Add sodium hydroxide solution dropwise to the above mixed solution while stirring. After the addition is complete, adjust the temperature to 80°C, keep it warm and stir for 2 hours, then filter, wash until neutral, dry, pulverize and grind to obtain the flame retardant.

[0055] As a further technical solution, the zinc salt is zinc sulfate, and the magnesium salt is magnesium chloride;

[0056] The zinc sulfate and magnesium chloride are mixed in a mass ratio of 1:5.

[0057] The mixed solution contains 3% zinc sulfate and 15% magnesium chloride by mass.

[0058] As a further technical solution: the mass ratio of the mixed solution to the sodium hydroxide solution is 1:1;

[0059] The concentration of the sodium hydroxide solution is 1.8 mol / L.

[0060] As a further technical solution, the method for preparing the intercalated bentonite is as follows:

[0061] Bentonite was evenly dispersed in deionized water and stirred until homogeneous. Sodium citrate was then added and stirred until homogeneous. The pH was adjusted to 10.5 and the temperature was adjusted to 75°C. The mixture was kept at this temperature to obtain a bentonite dispersion.

[0062] Ethanol was added to the bentonite dispersion and stirred until homogeneous. Then, trimethyl phosphonite and trimethylolphosphine oxide were added. The temperature was adjusted to 80°C and the mixture was stirred and kept at this temperature for 2 hours. After stirring, the mixture was filtered, washed, and dried to constant weight to obtain intercalated bentonite.

[0063] As a further technical solution, the mass ratio of bentonite, deionized water and sodium citrate is 10:50:3.

[0064] The mass ratio of the bentonite dispersion, ethanol, trimethyl phosphonite and trimethylolphosphine oxide is 35:10:3:1.

[0065] As a further technical solution: the method for preparing the modified hexagonal boron nitride particles is as follows:

[0066] Pre-modification treatment of hexagonal boron nitride particles:

[0067] Hexagonal boron nitride particles were uniformly dispersed in isopropanol solution, and then the pH was adjusted to 5.5 and the temperature was adjusted to 72℃. The mixture was kept warm and stirred for 30 min. Then, silane coupling agent solution was added and the mixture was stirred for 1 hour. The mixture was then filtered, washed, and dried to obtain pre-modified hexagonal boron nitride particles.

[0068] Pre-modified hexagonal boron nitride particles and polyvinyl chloride resin were mixed in a 3:2 mass ratio and added to a twin-screw extruder for melt extrusion to obtain composite particles.

[0069] The composite particles obtained above were added to an ultrasonic pulverizer and ultrasonically pulverized for 15 minutes to obtain modified hexagonal boron nitride particles.

[0070] As a further technical solution: the mass ratio of the hexagonal boron nitride particles to the isopropanol solution is 1:12;

[0071] The isopropanol solution has a mass fraction of 20%.

[0072] The silane coupling agent solution and isopropanol solution are mixed in a mass ratio of 1:10, and the silane coupling agent solution has a mass fraction of 7.5%.

[0073] The ultrasonic pulverizer has a power of 300W.

[0074] A method for preparing a composite cable includes the following steps:

[0075] (1) EVA resin, high-density polyethylene resin, calcium carbonate, flame retardant and intercalated bentonite are heated in a reactor at a temperature of 500°C for 2 hours until they are heated to become molten fluid materials.

[0076] (2) Place the required metal wires of the power supply line and communication line into the mold in sequence, extrude the molten fluid material into the mold through the extruder, and then perform cooling annealing on the mold. The cooling temperature is 55℃ and the duration is 1h to form the inner sheath.

[0077] (3) Place the wrapped power supply line and communication line together, heat and melt the outer sheath material with an injection molding machine, and then evenly attach it to the outer surface of the power supply line and communication line. After cooling and shaping, the outer sheath is formed.

[0078] Example 2

[0079] A composite cable includes a power supply line, a communication line, and an outer sheath. The surfaces of the power supply line and the communication line are covered by the inner sheath, and the outer sheath covers both the power supply line and the communication line simultaneously.

[0080] The inner sheath material is made of the following components by weight: 80 parts EVA resin, 25 parts high-density polyethylene resin, 18 parts calcium carbonate, 2 parts flame retardant, and 12 parts intercalated bentonite.

[0081] The outer sheath material is made of the following components by weight: 90 parts EVA resin, 24 parts high-density polyethylene resin, 15 parts calcium carbonate, 5 parts dioctyl phthalate, 2 parts flame retardant, 2 parts zinc oxide, 12 parts modified hexagonal boron nitride particles, 3 parts sodium stearate, 0.8 parts N,N-methylenebisacrylamide, and 1.6 parts polyethylene wax.

[0082] As a further technical solution, the method for preparing the flame retardant is as follows:

[0083] Weigh the zinc salt and magnesium salt separately, then mix them together and add them to deionized water. Stir the solution to obtain a mixed solution.

[0084] Add sodium hydroxide solution dropwise to the above mixed solution while stirring. After the addition is complete, adjust the temperature to 80°C, keep it warm and stir for 2 hours, then filter, wash until neutral, dry, pulverize and grind to obtain the flame retardant.

[0085] As a further technical solution, the zinc salt is zinc sulfate, and the magnesium salt is magnesium chloride;

[0086] The zinc sulfate and magnesium chloride are mixed in a mass ratio of 1:5.

[0087] The mixed solution contains 3% zinc sulfate and 15% magnesium chloride by mass.

[0088] As a further technical solution: the mass ratio of the mixed solution to the sodium hydroxide solution is 1:1;

[0089] The concentration of the sodium hydroxide solution is 1.8 mol / L.

[0090] As a further technical solution, the method for preparing the intercalated bentonite is as follows:

[0091] Bentonite was evenly dispersed in deionized water and stirred until homogeneous. Sodium citrate was then added and stirred until homogeneous. The pH was adjusted to 10.5 and the temperature was adjusted to 75°C. The mixture was kept at this temperature to obtain a bentonite dispersion.

[0092] Ethanol was added to the bentonite dispersion and stirred until homogeneous. Then, trimethyl phosphonite and trimethylolphosphine oxide were added. The temperature was adjusted to 80°C and the mixture was stirred and kept at this temperature for 2 hours. After stirring, the mixture was filtered, washed, and dried to constant weight to obtain intercalated bentonite.

[0093] As a further technical solution, the mass ratio of bentonite, deionized water and sodium citrate is 10:50:3.

[0094] The mass ratio of the bentonite dispersion, ethanol, trimethyl phosphonite and trimethylolphosphine oxide is 35:10:3:1.

[0095] As a further technical solution: the method for preparing the modified hexagonal boron nitride particles is as follows:

[0096] Pre-modification treatment of hexagonal boron nitride particles:

[0097] Hexagonal boron nitride particles were uniformly dispersed in isopropanol solution, and then the pH was adjusted to 5.5 and the temperature was adjusted to 72℃. The mixture was kept warm and stirred for 30 min. Then, silane coupling agent solution was added and the mixture was stirred for 1 hour. The mixture was then filtered, washed, and dried to obtain pre-modified hexagonal boron nitride particles.

[0098] Pre-modified hexagonal boron nitride particles and polyvinyl chloride resin were mixed in a 3:2 mass ratio and added to a twin-screw extruder for melt extrusion to obtain composite particles.

[0099] The composite particles obtained above were added to an ultrasonic pulverizer and ultrasonically pulverized for 15 minutes to obtain modified hexagonal boron nitride particles.

[0100] As a further technical solution: the mass ratio of the hexagonal boron nitride particles to the isopropanol solution is 1:12;

[0101] The isopropanol solution has a mass fraction of 20%.

[0102] The silane coupling agent solution and isopropanol solution are mixed in a mass ratio of 1:10, and the silane coupling agent solution has a mass fraction of 7.5%.

[0103] The ultrasonic pulverizer has a power of 300W.

[0104] A method for preparing a composite cable includes the following steps:

[0105] (1) EVA resin, high-density polyethylene resin, calcium carbonate, flame retardant and intercalated bentonite are heated in a reactor at a temperature of 500°C for 2 hours until they are heated to become molten fluid materials.

[0106] (2) Place the required metal wires of the power supply line and communication line into the mold in sequence, extrude the molten fluid material into the mold through the extruder, and then perform cooling annealing on the mold. The cooling temperature is 55℃ and the duration is 1h to form the inner sheath.

[0107] (3) Place the wrapped power supply line and communication line together, heat and melt the outer sheath material with an injection molding machine, and then evenly attach it to the outer surface of the power supply line and communication line. After cooling and shaping, the outer sheath is formed.

[0108] Example 3

[0109] A composite cable includes a power supply line, a communication line, and an outer sheath. The surfaces of the power supply line and the communication line are covered by the inner sheath, and the outer sheath covers both the power supply line and the communication line simultaneously.

[0110] The inner sheath material is made of the following components by weight: 76 parts EVA resin, 23 parts high-density polyethylene resin, 17 parts calcium carbonate, 1.5 parts flame retardant, and 8 parts intercalated bentonite.

[0111] The outer sheath material is made of the following components by weight: 88 parts EVA resin, 21 parts high-density polyethylene resin, 12 parts calcium carbonate, 4 parts dioctyl phthalate, 1.5 parts flame retardant, 1 part zinc oxide, 11 parts modified hexagonal boron nitride particles, 2 parts sodium stearate, 0.5 parts N,N-methylenebisacrylamide, and 1.2 parts polyethylene wax.

[0112] As a further technical solution, the method for preparing the flame retardant is as follows:

[0113] Weigh the zinc salt and magnesium salt separately, then mix them together and add them to deionized water. Stir the solution to obtain a mixed solution.

[0114] Add sodium hydroxide solution dropwise to the above mixed solution while stirring. After the addition is complete, adjust the temperature to 80°C, keep it warm and stir for 2 hours, then filter, wash until neutral, dry, pulverize and grind to obtain the flame retardant.

[0115] As a further technical solution, the zinc salt is zinc sulfate, and the magnesium salt is magnesium chloride;

[0116] The zinc sulfate and magnesium chloride are mixed in a mass ratio of 1:5.

[0117] The mixed solution contains 3% zinc sulfate and 15% magnesium chloride by mass.

[0118] As a further technical solution: the mass ratio of the mixed solution to the sodium hydroxide solution is 1:1;

[0119] The concentration of the sodium hydroxide solution is 1.8 mol / L.

[0120] As a further technical solution, the method for preparing the intercalated bentonite is as follows:

[0121] Bentonite was evenly dispersed in deionized water and stirred until homogeneous. Sodium citrate was then added and stirred until homogeneous. The pH was adjusted to 10.5 and the temperature was adjusted to 75°C. The mixture was kept at this temperature to obtain a bentonite dispersion.

[0122] Ethanol was added to the bentonite dispersion and stirred until homogeneous. Then, trimethyl phosphonite and trimethylolphosphine oxide were added. The temperature was adjusted to 80°C and the mixture was stirred and kept at this temperature for 2 hours. After stirring, the mixture was filtered, washed, and dried to constant weight to obtain intercalated bentonite.

[0123] As a further technical solution, the mass ratio of bentonite, deionized water and sodium citrate is 10:50:3.

[0124] The mass ratio of the bentonite dispersion, ethanol, trimethyl phosphonite and trimethylolphosphine oxide is 35:10:3:1.

[0125] As a further technical solution: the method for preparing the modified hexagonal boron nitride particles is as follows:

[0126] Pre-modification treatment of hexagonal boron nitride particles:

[0127] Hexagonal boron nitride particles were uniformly dispersed in isopropanol solution, and then the pH was adjusted to 5.5 and the temperature was adjusted to 72℃. The mixture was kept warm and stirred for 30 min. Then, silane coupling agent solution was added and the mixture was stirred for 1 hour. The mixture was then filtered, washed, and dried to obtain pre-modified hexagonal boron nitride particles.

[0128] Pre-modified hexagonal boron nitride particles and polyvinyl chloride resin were mixed in a 3:2 mass ratio and added to a twin-screw extruder for melt extrusion to obtain composite particles.

[0129] The composite particles obtained above were added to an ultrasonic pulverizer and ultrasonically pulverized for 15 minutes to obtain modified hexagonal boron nitride particles.

[0130] As a further technical solution: the mass ratio of the hexagonal boron nitride particles to the isopropanol solution is 1:12;

[0131] The isopropanol solution has a mass fraction of 20%.

[0132] The silane coupling agent solution and isopropanol solution are mixed in a mass ratio of 1:10, and the silane coupling agent solution has a mass fraction of 7.5%.

[0133] The ultrasonic pulverizer has a power of 300W.

[0134] A method for preparing a composite cable includes the following steps:

[0135] (1) EVA resin, high-density polyethylene resin, calcium carbonate, flame retardant and intercalated bentonite are heated in a reactor at a temperature of 500°C for 2 hours until they are heated to become molten fluid materials.

[0136] (2) Place the required metal wires of the power supply line and communication line into the mold in sequence, extrude the molten fluid material into the mold through the extruder, and then perform cooling annealing on the mold. The cooling temperature is 55℃ and the duration is 1h to form the inner sheath.

[0137] (3) Place the wrapped power supply line and communication line together, heat and melt the outer sheath material with an injection molding machine, and then evenly attach it to the outer surface of the power supply line and communication line. After cooling and shaping, the outer sheath is formed.

[0138] Comparative Example 1: The difference from Example 1 is that no intercalated bentonite was added;

[0139] Comparative Example 2: The difference from Example 1 is that no modified hexagonal boron nitride particles were added;

[0140] test:

[0141] Thermal stability performance testing:

[0142] Take 10 mg of the inner sheath sample from the example and comparative examples and place it in a crucible. Under a nitrogen atmosphere, the initial equilibrium temperature is 40°C, and then the temperature is increased to 800°C at a rate of 10°C / min.

[0143] Table 1

[0144]

[0145] As can be seen from Table 1, the thermal stability of the inner sheath material prepared by the present invention is greatly increased.

[0146] Oil resistance test:

[0147] The sheath samples of the examples and comparative exceptions were subjected to an oil aging test at 70°C for 160 hours. The tensile properties before and after the aging test were tested using a universal testing machine in accordance with GB / T528-2009.

[0148] Table 2

[0149]

[0150] As can be seen from Table 2, the outer sheath material of the composite cable prepared by the present invention has excellent oil aging resistance, thereby extending its service life, especially when working in environments with high oil pollution.

[0151] The limiting oxygen index tests of the sheath materials in the examples and comparative examples were conducted according to ISO 4589-2 requirements:

[0152] Table 3

[0153]

[0154] As can be seen from Table 3, the inner sheath material prepared by the present invention has a high limiting oxygen index. By increasing the limiting oxygen index, the flame retardant performance of the material can be significantly improved.

[0155] The volume resistivity of the sheath materials in the examples and comparative exceptions was tested in accordance with GB / T 1410-2006.

[0156] Table 4

[0157]

[0158] As can be seen from Table 4, the volume resistivity of the outer sheath material of the present invention is significantly improved, indicating that the electrical insulation performance of the outer sheath material is greatly enhanced.

[0159] Using Example 1 as the base sample, the effects of different amounts of intercalated bentonite added on the flame retardant properties of the inner sheath material were compared. Figure 1 .

[0160] Using Example 1 as the base sample, the effects of different amounts of modified hexagonal boron nitride on the tensile properties of the outer sheath were compared. Figure 2 .

[0161] 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 alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A composite cable, characterized in that, It includes a power supply line, a communication line, and an outer sheath. The surface of the power supply line and the communication line is covered by the inner sheath, and the outer sheath covers both the power supply line and the communication line. The inner sheath material is made of the following components by weight: 70-80 parts EVA resin, 21-25 parts high-density polyethylene resin, 15-18 parts calcium carbonate, 1-2 parts flame retardant, and 6-12 parts intercalated bentonite. The outer sheath material is made of the following components by weight: 85-90 parts EVA resin, 18-24 parts high-density polyethylene resin, 6-15 parts calcium carbonate, 3-5 parts dioctyl phthalate, 1-2 parts flame retardant, 0.5-2 parts zinc oxide, 8-12 parts modified hexagonal boron nitride particles, 1-3 parts sodium stearate, 0.3-0.8 parts N,N-methylenebisacrylamide, and 1-1.6 parts polyethylene wax; The method for preparing the intercalated bentonite is as follows: Bentonite is uniformly dispersed in deionized water, stirred evenly, and then sodium citrate is added and stirred evenly. The pH is adjusted to 10.5, the temperature is adjusted to 75°C, and the mixture is kept at this temperature to obtain a bentonite dispersion. Ethanol is added to the bentonite dispersion, stirred evenly, and then trimethyl phosphonite and trimethylolphosphatidylcholine are added. The temperature is adjusted to 80°C, and the mixture is kept at this temperature and stirred for 2 hours. After stirring, the mixture is filtered, washed, and dried to constant weight to obtain the intercalated bentonite. The mass ratio of bentonite, deionized water, and sodium citrate is 10:50:

3. The mass ratio of the bentonite dispersion, ethanol, trimethyl phosphonite, and trimethylolphosphatidylcholine is 35:10:3:

1. The method for preparing the modified hexagonal boron nitride particles is as follows: Pre-modification treatment of hexagonal boron nitride particles: Hexagonal boron nitride particles are uniformly dispersed in isopropanol solution, then the pH is adjusted to 5.5, the temperature is adjusted to 72℃, and the mixture is kept warm and stirred for 30 min. Then, silane coupling agent solution is added, and the mixture is stirred and reacted for 1 hour. Then, the mixture is filtered, washed, and dried to obtain pre-modified hexagonal boron nitride particles. Pre-modified hexagonal boron nitride particles and polyvinyl chloride resin were mixed in a 3:2 mass ratio and added to a twin-screw extruder for melt extrusion to obtain composite particles. The composite particles obtained above were added to an ultrasonic pulverizer and ultrasonically pulverized for 15 minutes to obtain modified hexagonal boron nitride particles.

2. The composite cable according to claim 1, characterized in that, The method for preparing the flame retardant is as follows: Weigh the zinc salt and magnesium salt separately, then mix them together and add them to deionized water. Stir the solution to obtain a mixed solution. Add sodium hydroxide solution dropwise to the above mixed solution while stirring. After the addition is complete, adjust the temperature to 80°C, keep it warm and stir for 2 hours, then filter, wash until neutral, dry, pulverize and grind to obtain the flame retardant.

3. The composite cable according to claim 2, characterized in that, The zinc salt is zinc sulfate, and the magnesium salt is magnesium chloride; The zinc sulfate and magnesium chloride are mixed in a mass ratio of 1:

5. The mixed solution contains 3% zinc sulfate and 15% magnesium chloride by mass.

4. A composite cable according to claim 2, characterized in that: The mass ratio of the mixed solution to the sodium hydroxide solution is 1:

1. The concentration of the sodium hydroxide solution is 1.8 mol / L.

5. A composite cable according to claim 1, characterized in that: The mass ratio of the hexagonal boron nitride particles to the isopropanol solution is 1:

12. The isopropanol solution has a mass fraction of 20%. The silane coupling agent solution and isopropanol solution are mixed in a mass ratio of 1:10, and the silane coupling agent solution has a mass fraction of 7.5%. The ultrasonic pulverizer has a power of 300W.

6. The method for preparing a composite cable according to claim 1, characterized in that: Includes the following steps: (1) EVA resin, high-density polyethylene resin, calcium carbonate, flame retardant and intercalated bentonite are heated in a reactor at a temperature of 500°C for 2 hours until they are heated to become molten fluid materials. (2) Place the required metal wires of the power supply line and communication line into the mold in sequence, extrude the molten fluid material into the mold through the extruder, and then perform cooling annealing on the mold. The cooling temperature is 55°C and the duration is 1 hour to form the inner sheath. (3) Place the wrapped power supply line and communication line together, heat and melt the outer sheath material with an injection molding machine, and then evenly apply it to the outer surface of the power supply line and communication line. After cooling and shaping, the outer sheath is formed.

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