Stretch-resistant insulated cable layer and preparation method thereof

Abstract

The invention discloses a tensile insulated cable layer and a preparation method thereof, solves the problem that low-temperature embrittlement and mechanical properties of a traditional insulated cable layer are difficult to synergistically improve, and constructs a high-elasticity and high-toughness base material taking an ethylene-vinyl acetate copolymer and an acrylonitrile-butadiene-styrene copolymer as cores. Glass fibers are synchronously introduced to construct a three-dimensional rigid reinforced network, and mica powder is added to optimize the interlaminar shear performance. According to the material system, the cable layer can still keep excellent impact resistance at extremely low temperature, the impact brittle temperature is reduced compared with the prior art, meanwhile, the tensile strength is improved by means of the macromolecular chain entanglement effect of the ethylene-vinyl acetate copolymer and the acrylonitrile-butadiene-styrene copolymer and the load transmission effect of the glass fiber, and the service life of the cable layer is prolonged. And the reliability and the service life of the cable in harsh scenes such as new energy power transmission and polar scientific investigation are remarkably improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cable manufacturing, in particular to a tensile-resistant insulating cable layer and a preparation method thereof. BACKGROUND

[0002] Cable manufacturing technology is a multi-disciplinary field integrating material science, precision machining and electrical engineering, and its core process includes four links: conductor processing, insulation layer forming, structure compounding and function strengthening. The conductor processing takes copper or aluminum as the base material, and realizes the balance between electrical conductivity and flexibility through multi-pass wire drawing and annealing treatment, and then forms a multi-core structure through bunching or concentric stranding. Some products use compacting technology to compress the circular conductor into a semicircular or fan-shaped structure to reduce the geometric size. The insulation layer forming uses thermoplastic materials such as polyvinyl chloride and cross-linked polyethylene, and forms a continuous insulation layer through high-temperature extrusion process. The key parameters include eccentricity, surface roughness and pinhole rate to ensure stable electrical insulation performance. In the structure compounding stage, the multi-core insulated wire core is stranded into a circular shape by a cable forming machine, and polypropylene ropes or glass fiber ropes are filled simultaneously to maintain the circularity, and non-woven fabric is wrapped to prevent loosening. The outer sheath is made of polyethylene or flame-retardant polyvinyl chloride material, and a mechanical protection layer is formed by extrusion coating. Some products add steel belt armor or aluminum plastic composite belt shielding layer to improve the anti-interference ability. In the function strengthening link, flame retardation is realized by adding aluminum hydroxide or magnesium hydroxide.

[0003] However, the existing technical system has significant performance conflicts. A single matrix material cannot balance tensile strength and flexibility. For example, although polyvinyl chloride has high hardness, its low-temperature embrittlement temperature is low, which leads to brittle fracture under complex stress conditions. The compatibility of functional fillers and organic matrix is poor. Although aluminum hydroxide flame retardant can form a ceramic layer to resist fire, the Al2O3 generated by its decomposition can increase the porosity of the material, reducing the volume resistivity and significantly increasing the risk of electric leakage. The adaptability to extreme environments is insufficient. Traditional materials have low impact strength in low-temperature environments, and the structure is prone to thermal aging in high-temperature environments, which makes it difficult to meet the needs of harsh scenarios such as new energy power transmission or rail transportation, restricting the large-scale application of cable products in high-end fields. Traditional flame-retardant cable layers require additional reinforcing agents or insulation aids, resulting in complex processes and high costs.

[0004] Therefore, it is of great significance to provide a tensile-resistant insulating cable layer and a preparation method thereof. SUMMARY

[0005] The present application aims to provide a tensile-resistant insulating cable layer and a preparation method thereof to solve the problems raised in the background.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical solutions: A tensile-resistant insulating cable layer prepared from the following components: 50-70 parts by weight of polyvinyl chloride, 20-40 parts by weight of cross-linked polyethylene, 5-20 parts by weight of aluminum hydroxide, 5-15 parts by weight of calcium carbonate, 5-15 parts by weight of ethylene-vinyl acetate copolymer, 3-10 parts by weight of acrylonitrile-butadiene-styrene copolymer, 5-15 parts by weight of glass fiber, 0.5-2 parts by weight of silane coupling agent, and 5-12 parts by weight of mica powder.

[0007] A tensile-resistant insulating cable layer and a preparation method thereof, comprising the following preparation steps: Step one, plasticizing: 50-70 parts by weight of polyvinyl chloride and 20-40 parts by weight of cross-linked polyethylene are put into a mixer, the temperature is 90-100℃, the rotating speed is 50-100rpm, and after stirring for 15-20 minutes, the temperature is raised to 110-120℃, the rotating speed is 500-800rpm, and stirring is performed for 15-20 minutes to obtain a mixture.

[0008] Step two, primary mixing: 5-15 parts by weight of ethylene-vinyl acetate copolymer, 3-10 parts by weight of acrylonitrile-butadiene-styrene copolymer, and 0.5-2 parts by weight of silane coupling agent are added for low-speed stirring, the rotating speed is 100-150rpm, the mixing temperature is 120-130℃, and the mixing time is 5-10 minutes, then 5-15 parts by weight of calcium carbonate and 5-20 parts by weight of aluminum hydroxide are added for high-speed stirring, the rotating speed is 400-600rpm, the mixing temperature is 120-130℃, and the mixing time is 5-10 minutes to prepare a mixed rubber material.

[0009] Step three, cooling: the mixed rubber material is laid flat on a cooling conveyor belt and then slowly cooled in a cooling water tank at 20-30℃, the cooling speed is 3-5℃ / min, and a cooled rubber material is obtained.

[0010] Step four, secondary mixing: the cooled rubber material is put into a double-screw extruder, 5-15 parts by weight of glass fiber and 5-12 parts by weight of mica powder with a flake diameter of 50-150μm are added from the side feeding port, the feeding section temperature is 140-150℃, the melting section temperature is 160-170℃, the metering section temperature is 175-185℃, and the screw rotating speed is 200-300rpm to obtain a pre-product.

[0011] Step five, molding: the pre-product is subjected to a molding process using a molding machine, the molding machine is set at a temperature of 170-180℃, a pressure of 10-15MPa, and a holding time of 5-10 minutes, and after demolding, natural cooling is performed to room temperature to obtain a finished product.

[0012] As a preferred technical solution of the present application, the mica powder needs to be selected in a specification with a flake diameter of 50-150μm.

[0013] As a preferred technical solution of the present application, the temperature of the first stirring mixer in step one is 90-100℃, the rotating speed is 50-100rpm, and the stirring time is 15-20 minutes.

[0014] As a preferred technical solution of the present application, the rotating speed of the low-speed stirring in step two is 100-150rpm, the temperature is 120-130℃, and the time is 5-10 minutes; the rotating speed of the high-speed stirring is 400-600rpm, the temperature is 120-130℃, and the time is 5-10 minutes.

[0015] As a preferred technical solution of the present application, the temperature of the feeding section of the double-screw extruder in step four is set to 140-150℃, the temperature of the melting section is set to 160-170℃, the temperature of the metering section is set to 175-185℃, and the rotating speed of the screw is set to 200-300rpm.

[0016] As a preferred technical solution of the present application, the temperature of the molding machine in step five is set to 170-180℃, the pressure is set to 10-15MPa, and the time is 5-10 minutes.

[0017] Compared with the prior art, the present application has the following beneficial effects: 1. The present application forms a "hard-soft-tough" gradient transition structure through the multi-blending design of polyvinyl chloride, cross-linked polyethylene, ethylene-vinyl acetate copolymer, and acrylonitrile-butadiene-styrene copolymer, and the molecular-level modification of the interface by a silane coupling agent. The tensile strength is significantly improved compared with a single polyvinyl chloride matrix, the low-temperature embrittlement temperature is reduced, and it is suitable for power transmission in extremely cold regions.

[0018] 2. The present application adopts a synergistic reinforcement strategy of glass fiber and mica powder: the glass fiber is arranged in the axial direction of the cable to form a "linear reinforcing rib" to improve the axial tensile strength; the mica powder is randomly distributed in the radial direction to form a "sheet-shaped barrier layer" to improve the transverse tear strength; and the two form a chemical bond with the matrix through a silane coupling agent to improve the interfacial shear strength and avoid the performance degradation caused by the pulling out of traditional fillers. Compared with a single glass fiber reinforced system, the fatigue resistance is improved, the wear resistance is reduced, and the long-term stability of the cable layer in a complex stress environment is significantly improved.

[0019] 3. The present application realizes the integration of three major functions through the composite modification technology of aluminum hydroxide, calcium carbonate, and silane coupling agent, improves the material density, and significantly reduces the risk of partial discharge. Compared with the traditional halogen flame-retardant system, the smoke density grade is reduced, which provides a reliable guarantee for the fire safety of personnel-intensive places. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work belong to the protection scope of the present application.

[0021] Polyvinyl chloride is a thermoplastic polymer material polymerized by chloroethylene monomer. Because of the high content of chlorine atoms in the molecular chain, it has excellent flame retardance, electrical insulation and chemical corrosion resistance. In the tensile-resistant insulation cable layer of the present patent, it is used as the core matrix material. It not only provides basic tensile strength and hardness support through its rigid skeleton structure, but also forms chemical bonding with silane coupling agent by using its polarity characteristics to enhance the interfacial compatibility with cross-linked polyethylene and aluminum hydroxide. In addition, the heat absorption characteristics of chlorine atoms at high temperature can cooperate with the flame retardant effect of aluminum hydroxide to reduce the material heat release rate. Furthermore, the processing fluidity of polyvinyl chloride enables it to effectively wrap rigid fillers such as glass fibers and mica powder during the mixing process, preventing stress concentration caused by filler aggregation, and ultimately achieving comprehensive improvement of the cable layer in terms of tensile strength, flame retardance, insulation reliability and processing stability.

[0022] Ethylene-vinyl acetate copolymer is a copolymer of ethylene and vinyl acetate, and its vinyl acetate content can be adjusted to give the material softness, elasticity and low temperature resistance. Its rubber-like elasticity can absorb impact energy and improve the flexibility of the cable layer; low-temperature flexibility prevents low-temperature embrittlement; at the same time, ethylene-vinyl acetate copolymer forms chemical bonding with silane coupling agent to enhance interfacial compatibility, avoid delamination defects of traditional blends, and synergistically improve tensile strength and wear resistance.

[0023] Acrylonitrile-butadiene-styrene copolymer is a thermoplastic plastic copolymerized by acrylonitrile, butadiene and styrene, which has chemical resistance, toughness and processability. In the present patent, acrylonitrile-butadiene-styrene copolymer is used as an impact modifier. Its butadiene rubber phase absorbs impact energy to improve elongation at break, while the acrylonitrile phase enhances surface hardness and chemical resistance, and the styrene phase optimizes processing fluidity, synergistically improving fatigue resistance with glass fiber and mica powder, and solving the brittleness problem caused by traditional filler reinforcement.

[0024] Aluminum hydroxide decomposes and absorbs heat and releases water vapor to dilute oxygen, and cooperates with the CO2 generated by the decomposition of calcium carbonate to increase the oxygen index; silane coupling agent changes the surface of aluminum hydroxide / calcium carbonate from hydrophilic to hydrophobic, reduces the leakage current channel caused by filler aggregation, and improves the volume resistivity; the nanoscale dispersion of calcium carbonate fills the pores between glass fibers and mica, making the material denser and significantly reducing the risk of partial discharge.

[0025] When preparing the stretch-resistant cable insulation layer through plastication, low-speed stirring (90-100°C, 50-100 rpm, 15-20 minutes) is initially performed. Polyvinyl chloride and cross-linked polyethylene are in solid or semi-solid form. Low-speed stirring allows the two materials to slowly contact and penetrate each other in the mixer. Slow stirring at this stage avoids excessive shear forces generated by high-speed stirring, preventing undesirable effects such as excessive dispersion and localized overheating before the materials are fully contacted. This ensures a gentle and uniform initial mixing of the two materials, laying the foundation for subsequent, more in-depth mixing reactions. Initial high-speed stirring may cause localized temperature increases while other areas remain cool, resulting in uneven mixing and affecting the quality of the final product. High-speed stirring is then applied (110-120°C, 500-800 rpm, 15-20 minutes). After this period of low-speed stirring, the materials are initially evenly mixed. At this point, the temperature rises to 110-120°C, increasing the material's mobility. High-speed stirring provides greater shear force, intensifying the interaction between the material molecules and further promoting in-depth mixing of the two materials. Simultaneously, high-speed stirring helps break down the internal microstructure of the materials, allowing the polyvinyl chloride and cross-linked polyethylene to blend better and achieve more complete plasticization, resulting in a uniform and stable mixture that meets the material performance requirements of the tensile-resistant insulation cable layer, improving production efficiency and reducing production costs.

[0026] If no specific techniques or conditions are specified in the examples, the experiments were carried out according to the techniques or conditions described in the literature in the field or according to the product instructions. All reagents or instruments used without specifying the manufacturer are commercially available conventional products.

[0027] Example 1

[0028] The present invention provides a tensile-resistant insulating cable layer, which is prepared from the following components: 60 parts by weight of polyvinyl chloride, 30 parts by weight of cross-linked polyethylene, 15 parts by weight of aluminum hydroxide, 10 parts by weight of calcium carbonate, 10 parts by weight of ethylene-vinyl acetate copolymer, 7 parts by weight of acrylonitrile-butadiene-styrene copolymer, 10 parts by weight of glass fiber, 1.2 parts by weight of a silane coupling agent, and 8 parts by weight of mica powder.

[0029] A tensile-resistant insulating cable layer and a preparation method thereof, comprising the following preparation steps: Step 1, plasticizing: 60 parts by weight of polyvinyl chloride and 30 parts by weight of cross-linked polyethylene are put into a mixer at 95°C and a rotation speed of 75 rpm. After stirring for 17 minutes, the temperature is raised to 115°C and the rotation speed is 650 rpm. Stir for 17 minutes to obtain a mixed material.

[0030] Step two, primary mixing: 10 parts by weight of ethylene-vinyl acetate copolymer, 7 parts by weight of acrylonitrile-butadiene-styrene copolymer, 1.2 parts by weight of silane coupling agent are added for low-speed stirring, the rotation speed is 125 rpm, the mixing temperature is 125°C, and the mixing time is 7 minutes, then 10 parts by weight of calcium carbonate, 15 parts by weight of aluminum hydroxide are added for high-speed stirring, the rotation speed is 500 rpm, the mixing temperature is 125°C, and the mixing time is 7 minutes, to obtain a mixed rubber.

[0031] Step three, cooling: the mixed rubber is laid flat on a cooling conveyor belt and then slowly cooled in a 25°C cooling water tank at a cooling rate of 4°C / min to obtain a cooled rubber.

[0032] Step four, secondary mixing: the cooled rubber is put into a twin-screw extruder, and 10 parts by weight of glass fiber and 8 parts by weight of mica powder with a flake diameter of 100 μm are added from the side feeding port, the feeding section temperature is 145°C, the melting section temperature is 165°C, the metering section temperature is 180°C, and the screw rotation speed is 250 rpm to obtain a pre-product.

[0033] Step five, molding: the pre-product is subjected to a molding process using a molding machine, the molding machine is set to a temperature of 175°C, a pressure of 12 MPa, and a holding time of 7 minutes, and then naturally cooled to room temperature after demolding to obtain a finished product.

[0034] Example two

[0035] A tensile-resistant insulating cable layer is prepared from the following components: 50 parts by weight of polyvinyl chloride, 20 parts by weight of crosslinked polyethylene, 5 parts by weight of aluminum hydroxide, 5 parts by weight of calcium carbonate, 5 parts by weight of ethylene-vinyl acetate copolymer, 3 parts by weight of acrylonitrile-butadiene-styrene copolymer, 5 parts by weight of glass fiber, 0.5 parts by weight of silane coupling agent, and 5 parts by weight of mica powder.

[0036] A tensile-resistant insulating cable layer and a preparation method thereof, comprising the following preparation steps: Step one, plastication: 50 parts by weight of polyvinyl chloride and 20 parts by weight of crosslinked polyethylene are put into a mixer, the temperature is 90°C, the rotation speed is 50 rpm, and stirring is performed for 15 minutes, then the temperature is raised to 110°C, the rotation speed is 500 rpm, and stirring is performed for 15 minutes to obtain a mixture.

[0037] Step 2, primary mixing: adding 5 parts by weight of ethylene-vinyl acetate copolymer, 3 parts by weight of acrylonitrile-butadiene-styrene copolymer, and 0.5 parts by weight of a silane coupling agent and stirring at low speed at a speed of 100 rpm, a mixing temperature of 120° C., and a mixing time of 5 minutes, then adding 5 parts by weight of calcium carbonate and 5 parts by weight of aluminum hydroxide and stirring at high speed at a speed of 400 rpm, a mixing temperature of 120° C., and a mixing time of 5 minutes to obtain a mixed rubber material.

[0038] Step 3: Cooling: Spread the mixed rubber material on a cooling conveyor belt, and then immerse it in a cooling water tank at 20°C for slow cooling at a cooling rate of 3°C / min to obtain a cooled rubber material.

[0039] Step 4, secondary mixing: feed the cooled rubber material into a twin-screw extruder, and at the same time add 5 parts by weight of glass fiber and 5 parts by weight of mica powder with a flake diameter of 50 μm from the side feeding port, the feeding section temperature is 140°C, the melting section temperature is 160°C, the metering section temperature is 175°C, and the screw speed is 200 rpm to obtain a pre-finished product.

[0040] Step 5: Molding: Use a molding machine to mold the pre-finished product. The molding machine is set to a temperature of 170° C. and a pressure of 10 MPa for 5 minutes. After demolding, it is naturally cooled to room temperature to obtain a finished product.

[0041] Example 3

[0042] A tensile-resistant insulating cable layer is prepared from the following components: 70 parts by weight of polyvinyl chloride, 30 parts by weight of cross-linked polyethylene, 20 parts by weight of aluminum hydroxide, 15 parts by weight of calcium carbonate, 15 parts by weight of ethylene-vinyl acetate copolymer, 10 parts by weight of acrylonitrile-butadiene-styrene copolymer, 15 parts by weight of glass fiber, 2 parts by weight of a silane coupling agent, and 12 parts by weight of mica powder.

[0043] A tensile-resistant insulating cable layer and a preparation method thereof, comprising the following preparation steps: Step 1, plasticizing: 70 parts by weight of polyvinyl chloride and 40 parts by weight of cross-linked polyethylene are put into a mixer at a temperature of 100°C and a rotation speed of 100 rpm. After stirring for 20 minutes, the temperature is raised to 120°C and the rotation speed is 800 rpm. Stir for 20 minutes to obtain a mixed material.

[0044] Step two, primary mixing: 15 parts by weight of ethylene-vinyl acetate copolymer, 10 parts by weight of acrylonitrile-butadiene-styrene copolymer, and 2 parts by weight of silane coupling agent were added and stirred at a low speed of 150 rpm, and the mixing temperature was 130°C and the mixing time was 10 minutes. Then 15 parts by weight of calcium carbonate and 20 parts by weight of aluminum hydroxide were added and stirred at a high speed of 600 rpm, and the mixing temperature was 130°C and the mixing time was 10 minutes, to obtain a mixed rubber.

[0045] Step three, cooling: the mixed rubber was laid flat on a cooling conveyor belt and then slowly cooled in a 30°C cooling water tank at a cooling rate of 5°C / min to obtain a cooled rubber.

[0046] Step four, secondary mixing: the cooled rubber was put into a double screw extruder, and 15 parts by weight of glass fiber and 12 parts by weight of mica powder with a flake diameter of 150 μm were added from the side feeding port. The feeding section temperature was 150°C, the melting section temperature was 170°C, the metering section temperature was 185°C, and the screw rotation speed was 300 rpm to obtain a pre-product.

[0047] Step five, molding: the pre-product was molded using a molding machine, and the molding machine was set at a temperature of 180°C, a pressure of 15 MPa, and a holding time of 10 minutes. After demolding, the product was naturally cooled to room temperature to obtain a finished product.

[0048] Comparative Example One, The difference from Example One is that the prepared tensile-resistant insulation cable layer does not introduce ethylene-vinyl acetate copolymer.

[0049] Comparative Example Two, The difference from Example One is that the prepared tensile-resistant insulation cable layer does not introduce acrylonitrile-butadiene-styrene copolymer.

[0050] Comparative Example Three, The difference from Example One is that the prepared tensile-resistant insulation cable layer does not introduce glass fiber and mica powder.

[0051] Comparative Example Four, The difference from Example One is that the prepared tensile-resistant insulation cable layer does not introduce polyvinyl chloride.

[0052] Performance Test: I. Tensile Property Test: The tensile strength and elongation at break of the sample were measured, and a universal electronic testing machine was usually used to measure the solid material, and the results are shown in Table 1.

[0053] II. Low-temperature brittle fracture resistance test: The sample was placed in a low-temperature environmental test chamber and gradually cooled to the target test temperature at a preset cooling rate. After the sample temperature stabilized, it was quickly removed and subjected to impact testing using an impact tester with a specified pendulum energy. The brittle fracture of the sample was observed and recorded to determine the low-temperature brittle impact temperature. The results are shown in Table 1.

[0054] III. Insulation Performance Test: The insulation resistance was tested according to the standard GB / T 16927.3-2011 "General Specification for Insulation Resistance Test". The specific test conditions were as follows: a 500V DC voltage was applied, and the insulation resistance value was read after 1 minute. The dielectric strength was tested according to the standard GB / T 1408.1-2016 "Insulating Materials - Electric Strength Test Methods - Part 1: Test at Power Frequency". The results are shown in Table 2.

[0055] Table 1

[0056] As shown in the results of Table 1, compared with Comparative Examples 1, 2, 3, and 4, the low-temperature brittle temperature of the tensile-resistant insulation cable layer of the present patent was significantly reduced, and the tensile strength and elongation were significantly increased. The addition of glass fiber and mica powder also affected these properties. It can be concluded that the tensile-resistant insulation cable layer of the present patent can still maintain toughness in extremely low-temperature environments, effectively avoiding cable failure due to brittle fracture.

[0057] Table 2

[0058] As shown in the results of Table 2, Examples 1, 2, and 3 used a complete material formula, and the components synergistically interacted to make the cable layer have good insulation resistance and high dielectric strength. Compared with Examples 1, 2, and 3, the insulation resistance and dielectric strength of Comparative Examples 1, 2, and 3 also decreased. Ethylene-vinyl acetate copolymer plays a role in improving the intermolecular structure and increasing the density of the material. Its absence leads to a certain impact on the insulation performance of the cable layer. Acrylonitrile-butadiene-styrene copolymer may help enhance the overall performance of the material, including insulation performance. Its absence makes the insulation properties of the material worse. Glass fiber and mica powder may play a role in enhancing the insulation barrier and improving the electric field distribution in the material. This shows that ethylene-vinyl acetate copolymer, acrylonitrile-butadiene-styrene copolymer, glass fiber, and mica powder also play a certain role in improving the insulation performance of the cable layer. Compared with Examples 1, 2, and 3, the insulation resistance and dielectric strength of Comparative Example 4 significantly decreased. Polyvinyl chloride is one of the main insulation components of the cable layer. Its absence greatly damages the insulation foundation of the material, making it unable to provide sufficient insulation performance. This proves that polyvinyl chloride can significantly enhance the insulation performance of the cable layer.

[0059] The above merely illustrates the specific embodiments of the present application, but the technical features of the present application are not limited thereto. Any simple change, equivalent replacement or modification made on the basis of the present application to solve the basically same technical problem and realize the basically same technical effect shall be included in the protection scope of the present application.

Claims

1. A tensile-resistant insulating cable layer, characterized in that: The invention is prepared from the following components: 50-70 parts by weight of polyvinyl chloride, 20-40 parts by weight of cross-linked polyethylene, 5-20 parts by weight of aluminum hydroxide, 5-15 parts by weight of calcium carbonate, 5-15 parts by weight of ethylene-vinyl acetate copolymer, 3-10 parts by weight of acrylonitrile-butadiene-styrene copolymer, 5-15 parts by weight of glass fiber, 0.5-2 parts by weight of silane coupling agent, and 5-12 parts by weight of mica powder.

2. The method for preparing a tensile-resistant insulated cable layer according to claim 1, characterized in that: The method comprises the following preparation steps: Step 1, plasticizing: 50-70 parts by weight of polyvinyl chloride and 20-40 parts by weight of cross-linked polyethylene are put into a mixer, stirred evenly for the first time, then heated to 110-120°C, rotated at 500-800 rpm, and stirred for 15-20 minutes to obtain a mixed material; Step 2, primary mixing: adding 5-15 parts by weight of ethylene-vinyl acetate copolymer, 3-10 parts by weight of acrylonitrile-butadiene-styrene copolymer, and 0.5-2 parts by weight of a silane coupling agent to the mixture and stirring at a low speed, then adding 5-15 parts by weight of calcium carbonate and 5-20 parts by weight of aluminum hydroxide and stirring at a high speed to obtain a mixed rubber material; Step 3: Cooling: Spread the mixed rubber material on the cooling conveyor belt, and then immerse it in a cooling water tank at 20-30℃ to slowly cool it to obtain a cooled rubber material; Step 4, secondary mixing: feeding the cooled rubber material into a twin-screw extruder, and simultaneously adding 5-15 parts by weight of glass fiber and 5-12 parts by weight of mica powder from a side feed port to obtain a pre-finished product; Step 5: Molding: Use a molding machine to mold the pre-finished product, and then naturally cool it to room temperature after demoulding to obtain a finished product.

3. The method for preparing a tensile-resistant insulated cable layer according to claim 1 or 2, characterized in that: The mica powder should have a particle size of 50-150 μm.

4. The method for preparing a tensile-resistant insulated cable layer according to claim 2, characterized in that: In the first step, the temperature of the mixer is 90-100° C., the rotation speed is 50-100 rpm, and the stirring is performed for 15-20 minutes.

5. The method for preparing a tensile-resistant insulated cable layer according to claim 2, characterized in that: In the step 2, the low-speed stirring speed is 100-150 rpm, the temperature is 120-130° C., and the time is 5-10 minutes. The high-speed stirring speed is 400-600 rpm, the temperature is 120-130° C., and the time is 5-10 minutes.

6. The method for preparing a tensile-resistant insulated cable layer according to claim 2, characterized in that: In the step 4, the feeding section temperature of the twin-screw extruder is set to 140-150° C., the melting section temperature is set to 160-170° C., the metering section temperature is set to 175-185° C., and the screw speed is set to 200-300 rpm.

7. The method for preparing a tensile-resistant insulated cable layer according to claim 2, characterized in that: In the step 5, the temperature of the molding machine is set to 170-180° C., the pressure is set to 10-15 MPa, and the time is 5-10 minutes.

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