Aerial insulated cable skin material and preparation method thereof

Abstract

The invention relates to the field of adhesives, in particular to an aerial insulated cable skin material and a preparation method thereof. The overhead insulated cable skin material is prepared from the following raw materials: an ethylene-vinyl acetate copolymer, a temperature-resistant combination agent, an antioxidant, an ultraviolet absorbent, a flame retardant, functional resin and the like. The overhead insulated cable skin material prepared by the invention not only has excellent temperature resistance to cope with application in specific regional environments, but also can keep good weather resistance, aging resistance, moisture resistance, water resistance and the like at the same time, the comprehensive performance of the overhead insulated cable skin material is greatly improved, the application environment of the material is expanded, and on the other hand, the overhead insulated cable skin material has good application prospects. The electrical insulation performance of the prepared skin material is further improved, so that the skin material can cope with higher-grade and more complex working environments possibly facing in the future, and the skin material has an excellent application effect.

Description

Technical Field

[0001] The present application relates to the field of adhesives, and more specifically to an overhead insulated cable sheath material and a preparation method thereof. Background Art

[0002] With the continued growth of electricity demand and the acceleration of urbanization, the requirements for the safety, reliability, and environmental friendliness of power transmission equipment are becoming increasingly stringent. As an essential component of power transmission, overhead insulated cables play a vital role in modern power grids. As the outermost protective structure of the cable, the cable sheath material must not only provide physical protection to prevent the external environment from affecting the internal conductors, but also possess excellent electrical insulation properties to ensure safe and stable power transmission. Therefore, the development of high-performance cable sheath materials is of great significance for improving the operating efficiency and safety of the entire power system.

[0003] Currently, the sheath materials used in the widespread use of overhead insulated cables are primarily composed of polymers such as polyethylene (PE), cross-linked polyethylene (XLPE), and polyvinyl chloride (PVC). These materials, with their excellent mechanical properties, weather resistance, and electrical insulation, meet the basic requirements for cable use to a certain extent. For example, PE is widely used in harsh environments due to its excellent flexibility and impact resistance. XLPE is commonly used in high-voltage cable manufacturing due to its excellent heat aging resistance and high operating temperature range. PVC, due to its low cost and ease of processing and molding, has a broad application base in the low-voltage cable sector.

[0004] However, although the above materials have achieved good results in practical applications, with the development of power systems towards higher voltage levels and larger transmission capacities, existing cable sheath materials have gradually exposed some limitations. For example, the performance of existing material systems in cold and high temperature areas may be significantly affected by insufficient environmental adaptability, resulting in shortened cable life. Insufficient weather resistance, aging resistance and waterproof properties also further limit the application environment of such materials. On the other hand, although existing PE, XLPE and PVC materials already have certain electrical insulation properties, their insulation performance still needs to be further improved in the face of possible higher voltage levels and more complex working environments in the future. Summary of the Invention

[0005] Therefore, in order to effectively solve the above-mentioned problems, the applicant, after long-term research and development in this field, has proposed a surface material for an overhead insulated cable and a preparation method thereof. The surface material for an overhead insulated cable prepared by the present application not only has excellent temperature resistance to cope with applications in specific regional environments, but also maintains good weather resistance, aging resistance, moisture resistance and waterproofing properties, significantly improving its overall performance and expanding the application environment of this type of material. On the other hand, the surface material prepared by the present application further improves its electrical insulation performance to cope with higher-level and more complex working environments that may be encountered in the future, and has excellent application effects.

[0006] The surface material of the overhead insulated cable is composed of the following raw materials, calculated by mass: 40 to 60 parts of ethylene-vinyl acetate copolymer, 8 to 16 parts of heat-resistant combination agent, 0.6 to 1.2 parts of antioxidant, 1 to 1.8 parts of ultraviolet absorber, 6 to 10 parts of flame retardant, 1 to 2.5 parts of lubricant, 0.3 to 0.8 parts of coupling agent, 0.4 to 0.8 parts of anti-hydrolysis agent, and 20 to 35 parts of functional resin.

[0007] As a preferred solution, the melt index of the ethylene-vinyl acetate copolymer is 1.5-3 g / 10 min, under the conditions of 2.16 kg and 190°C.

[0008] As a preferred solution, the melt index of the ethylene-vinyl acetate copolymer is 2-2.3 g / 10 min, under the conditions of 2.16 kg and 190° C.

[0009] As a preferred solution, the vinyl acetate content of the ethylene-vinyl acetate copolymer is 20 to 35 wt%.

[0010] As a preferred solution, the vinyl acetate content of the ethylene-vinyl acetate copolymer is 25-30 wt%.

[0011] As a preferred solution, the mass ratio of the ethylene-vinyl acetate copolymer, the heat-resistant composite agent and the functional resin is (45-56): (10-14): (25-32).

[0012] As a preferred solution, the mass ratio of the ethylene-vinyl acetate copolymer, the heat-resistant composite agent and the functional resin is (48-52): (11-13): (26-30).

[0013] As a preferred solution, the temperature-resistant composition is a composition of polyimide, boron nitride and SEBS.

[0014] As a preferred solution, the mass ratio of the polyimide powder, boron nitride and SEBS is (3-4): (4-4.5): (5-7).

[0015] As a preferred solution, the mass ratio of the polyimide powder, boron nitride and SEBS is (3.3-3.5): (4.2-4.5): (6-6.5).

[0016] As a preferred solution, the average flake diameter of the boron nitride is 150 to 300 nm.

[0017] As a preferred solution, the average particle size of the polyimide powder is 2 to 4 μm.

[0018] As a preferred solution, the antioxidant is at least one of antioxidant DLTP, antioxidant 168, antioxidant 1010 and antioxidant 1076.

[0019] As a preferred solution, the antioxidant is the antioxidant DLTP.

[0020] As a preferred solution, the ultraviolet absorber is at least one of Tinuvin 329, UV-3853 and Tinuvin 1577.

[0021] As a preferred solution, the ultraviolet absorber is Tinuvin 329 or Tinuvin 1577.

[0022] As a preferred solution, the ultraviolet absorber is Tinuvin 329.

[0023] As a preferred solution, the flame retardant is at least one of magnesium hydroxide, aluminum hypophosphite, triphenyl phosphate and zinc borate.

[0024] As a preferred solution, the flame retardant is magnesium hydroxide, and its average particle size is 0.5 to 1.5 μm.

[0025] As a preferred solution, the lubricant is at least one of calcium stearate, oxidized polyethylene wax, pentaerythritol stearate and sodium stearate.

[0026] As a preferred solution, the lubricant is calcium stearate or oxidized polyethylene wax.

[0027] As a preferred solution, the coupling agent is at least one of a titanate coupling agent, an aluminate coupling agent and a phosphate coupling agent.

[0028] As a preferred solution, the coupling agent is titanate coupling agent KR-TTS.

[0029] As a preferred solution, the anti-hydrolysis agent is at least one of phenyl glycidyl ether, triphenyl phosphite and oxazoline derivatives.

[0030] As a preferred solution, the anti-hydrolysis agent is phenyl glycidyl ether.

[0031] As a preferred solution, the preparation method of the functional resin specifically comprises the following steps: S1: adding the base resin to an organic solvent and stirring to swell it, then sequentially adding trifluoroethyl acrylate, N-acryloylmorpholine and trimethylolpropane triacrylate, and passing nitrogen protection; S2: heating and adding dicumyl peroxide, and keeping the temperature to react; S3: after the reaction is completed, cooling the reaction solution and adding methanol for precipitation, filtering, washing with acetone and deionized water in a cycle, and vacuum drying until the moisture content is ≤0.2wt%, thereby obtaining the functional resin.

[0032] As a preferred solution, the preparation method of the functional resin specifically comprises the following steps: S1: adding a base resin to xylene, stirring and swelling at 70-75°C and 100-150 rpm for 2-3 hours, then sequentially adding trifluoroethyl acrylate, N-acryloylmorpholine and trimethylolpropane triacrylate, and introducing nitrogen for protection; S2: heating to 85-90°C, adding dicumyl peroxide, and then keeping the temperature to react for 7-8 hours; S3: after the reaction is completed, cooling the reaction solution to 45-50°C, adding methanol for precipitation, filtering, washing with acetone and deionized water 2-3 times each, and drying in vacuo at 60-70°C until the moisture content is ≤0.2wt%.

[0033] As a preferred solution, the matrix resin is an ethylene-vinyl acetate copolymer resin with a vinyl acetate content of 12 to 18 wt%.

[0034] As a preferred solution, the mass ratio of the base resin, trifluoroethyl acrylate, N-acryloylmorpholine and trimethylolpropane triacrylate is (6-8): (1.2-1.8): (1-1.2): (0.3-0.6).

[0035] As a preferred solution, the mass ratio of the base resin, trifluoroethyl acrylate, N-acryloylmorpholine and trimethylolpropane triacrylate is (6.5-7): (1.4-1.6): (1-1.1): (0.5-0.6).

[0036] In this application, by adding the above-mentioned functional resin, the heat resistance of the surface material can be greatly improved, and good weather resistance, aging resistance and moisture resistance can be maintained at the same time. By introducing N-acryloylmorpholine, the glass transition temperature of the material is significantly reduced. The morpholine ring structure provides molecular chain flexibility. At the same time, the acrylate side chain forms an entanglement with the EVA main chain, and at low temperatures, impact energy can still be absorbed through segment movement. On the other hand, the three functional cross-linking points of trimethylolpropane triacrylate form a three-dimensional network with the EVA molecular chain, limiting the molecular chain slippage at high temperatures. The cross-linking density is more suitable, ensuring the storage modulus of the material at high temperatures. At the same time, the fluorine groups in trifluoroethyl acrylate are enriched on the surface of the material to form a dense fluorinated layer, which reduces the surface energy and improves the barrier effect of the surface material on water molecules and corrosion molecules. The tertiary amine structure and the fluorocarbon chain synergistically absorb ultraviolet wavelengths, thereby greatly improving the weather resistance, moisture resistance and aging resistance of the surface material.

[0037] Furthermore, the addition of the functional resin in this application works together with the heat-resistant composite agent to not only promote internal covalent cross-linking and hydrogen bond formation, but also use polyimide powder as a rigid reinforcement island to improve the modulus through a mechanical interlocking effect. At the same time, through the action of boron nitride and SEBS, they are oriented along the extrusion direction to form a heat conduction path, thereby helping to improve the temperature resistance and increase the diffusion resistance and path of water molecules and corrosion molecules inside the surface material, thereby comprehensively improving the overall material performance.

[0038] The preparation method of the overhead insulated cable sheath material in the present application specifically includes the following steps: S1: putting ethylene-vinyl acetate copolymer, functional resin and heat-resistant composite agent into a high-speed mixer, controlling the speed to 1000-1200 rpm, and then adding the remaining raw materials in sequence, with an interval of 2-3 minutes each time, and mixing for 10-15 minutes each time; S2: adding to an internal mixer and mixing at 120-125°C for 4-6 minutes in the first stage, and at 140-145°C for 10-12 minutes in the second stage; S3: after the internal mixing is completed, adding to a twin-screw extruder for extrusion, the temperature range is 130-140°C, and the speed is 100-150 rpm. After completion, the product is calendered and formed using a three-roll calender to obtain the product.

[0039] This application has the following beneficial effects:

[0040] 1. The surface material of the overhead insulated cable finally prepared by the present application not only has excellent temperature resistance to cope with the application in specific regional environments, but also can maintain good weather resistance, aging resistance, moisture resistance and waterproof properties at the same time, greatly improving its comprehensive performance and expanding the application environment of this type of material. On the other hand, the surface material prepared by the present application further improves its electrical insulation performance to cope with higher-level and more complex working environments that may be faced in the future, and has excellent application effects.

[0041] 2. The surface material of the overhead insulated cable finally obtained in this application significantly reduces the glass transition temperature of the material by adding functional resin. The morpholine ring structure provides molecular chain flexibility. At the same time, the acrylate side chain forms an entanglement with the EVA main chain, and can still absorb impact energy through chain segment movement at low temperatures. On the other hand, the trifunctional cross-linking points of trimethylolpropane triacrylate form a three-dimensional network with the EVA molecular chain, which limits the slippage of the molecular chain at high temperature, and the cross-linking density is more appropriate, ensuring the storage modulus of the material at high temperature; at the same time, the fluorine groups in trifluoroethyl acrylate are enriched on the surface of the material to form a dense fluorinated layer, which reduces the surface energy and improves the barrier effect of the surface material on water molecules and corrosion molecules, thereby improving the heat resistance, weather resistance, moisture resistance and waterproof performance.

[0042] 3. The overhead insulated cable skin material finally obtained by the present application, the addition of functional resin and the heat-resistant combination agent work together, which can not only promote internal covalent cross-linking and hydrogen bond formation, but also use polyimide powder as a rigid reinforcement island to improve the modulus through the mechanical interlocking effect, and at the same time, through the action of boron nitride and SEBS, it is directional arranged along the extrusion direction to form a heat conduction path, thereby helping to improve the temperature resistance, and increase the diffusion resistance and path of water molecules and corrosion molecules inside the skin material, comprehensively improving the overall material performance. DETAILED DESCRIPTION

[0043] Example 1

[0044] The surface material of the overhead insulated cable is composed of the following raw materials, calculated by mass: 51.5 parts of ethylene-vinyl acetate copolymer, 12.2 parts of heat-resistant combination agent, 0.8 parts of antioxidant, 1.2 parts of ultraviolet absorber, 9.2 parts of flame retardant, 1.8 parts of lubricant, 0.4 parts of coupling agent, 0.5 parts of anti-hydrolysis agent, and 28.8 parts of functional resin.

[0045] The melt index of ethylene-vinyl acetate copolymer is 2 g / 10 min, the conditions are: 2.16 kg, 190° C., the content of vinyl acetate is 28 wt %, and the product of corresponding specifications is purchased from Sinopec.

[0046] The heat-resistant composite agent is a composition of polyimide, boron nitride and SEBS, with a mass ratio of 3.4:4.4:6.2.

[0047] The average flake diameter of boron nitride is 200 nm; the average particle size of polyimide powder is 3 μm, and they were purchased from Dongguan Caihua Plastic Technology Co., Ltd., China, and the corresponding specification products were sold. SEBS was purchased from the G1652 model product sold by Kraton Chemical in the United States.

[0048] The antioxidant is DLTP; the ultraviolet absorber is Tinuvin 329; the flame retardant is magnesium hydroxide with an average particle size of 1.2 μm; the lubricant is calcium stearate; the coupling agent is titanate coupling agent KR-TTS; and the anti-hydrolysis agent is phenyl glycidyl ether.

[0049] The preparation method of the functional resin specifically comprises the following steps, calculated by mass: S1: adding 6.8 parts of a base resin to 30 parts of xylene, stirring and swelling at 75°C and 120 rpm for 3 hours, then sequentially adding 1.5 parts of trifluoroethyl acrylate, 1.1 parts of N-acryloylmorpholine and 0.5 parts of trimethylolpropane triacrylate, and introducing nitrogen for protection; S2: heating to 90°C, adding 0.05 parts of diisopropylbenzene oxide, and then keeping the temperature for reaction for 7 hours; S3: after the reaction is completed, cooling the reaction solution to 50°C, adding methanol 6 times the volume of the reaction solution for precipitation, filtering, washing with acetone and deionized water 3 times each, and vacuum drying at 70°C to obtain the product.

[0050] The matrix resin is an ethylene-vinyl acetate copolymer resin with a vinyl acetate content of 16 wt %, which is purchased from Sinopec and sold with corresponding specifications.

[0051] The preparation method of the overhead insulated cable sheath material in this embodiment specifically includes the following steps: S1: putting ethylene-vinyl acetate copolymer, functional resin and heat-resistant combination agent into a high-speed mixer, controlling the speed to 1000 rpm, and then adding the remaining raw materials in sequence, with an interval of 2 minutes each time, and mixing for 12 minutes each time; S2: adding to an internal mixer and mixing for 4 minutes in the first stage at 120°C and 11 minutes in the second stage at 140°C; S3: after the internal mixing is completed, adding to a twin-screw extruder for extrusion, the temperature range is 130°C to 140°C, and the speed is 1200 rpm. After completion, the product is calendered and formed using a three-roll calender to obtain the product.

[0052] Example 2

[0053] The only difference between this embodiment and embodiment 1 is as follows:

[0054] The surface material of the overhead insulated cable is composed of the following raw materials, calculated by mass: 45.5 parts of ethylene-vinyl acetate copolymer, 10.5 parts of heat-resistant combination agent, 0.7 parts of antioxidant, 1.1 parts of ultraviolet absorber, 9.2 parts of flame retardant, 1.6 parts of lubricant, 0.4 parts of coupling agent, 0.6 parts of anti-hydrolysis agent, and 31.5 parts of functional resin.

[0055] The heat-resistant composite agent is a composition of polyimide, boron nitride and SEBS, with a mass ratio of 4:4.5:5.

[0056] Example 3

[0057] The only difference between this embodiment and embodiment 1 is as follows:

[0058] The surface material of the overhead insulated cable is composed of the following raw materials, calculated by mass: 55.5 parts of ethylene-vinyl acetate copolymer, 14 parts of heat-resistant combination agent, 0.8 parts of antioxidant, 1.3 parts of ultraviolet absorber, 9.1 parts of flame retardant, 1.5 parts of lubricant, 0.4 parts of coupling agent, 0.5 parts of anti-hydrolysis agent, and 25.3 parts of functional resin.

[0059] The heat-resistant composite agent is a composition of polyimide, boron nitride and SEBS, with a mass ratio of 3:4:7.

[0060] Comparative Example 1

[0061] This comparative example differs from Example 1 only in the following ways:

[0062] The surface material of the overhead insulated cable is composed of the following raw materials, calculated by mass: 65 parts of ethylene-vinyl acetate copolymer, 15.5 parts of heat-resistant combination agent, 0.8 parts of antioxidant, 1.2 parts of ultraviolet absorber, 9.2 parts of flame retardant, 1.8 parts of lubricant, 0.4 parts of coupling agent, 0.5 parts of anti-hydrolysis agent, and 10.5 parts of functional resin.

[0063] Comparative Example 2

[0064] This comparative example differs from Example 1 only in the following ways:

[0065] The surface material of the overhead insulated cable is composed of the following raw materials, calculated by mass: 75 parts of ethylene-vinyl acetate copolymer, 3.5 parts of heat-resistant combination agent, 0.8 parts of antioxidant, 1.2 parts of ultraviolet absorber, 9.2 parts of flame retardant, 1.8 parts of lubricant, 0.4 parts of coupling agent, 0.5 parts of anti-hydrolysis agent, and 25 parts of functional resin.

[0066] Comparative Example 3

[0067] This comparative example differs from Example 1 only in the following ways:

[0068] The heat-resistant composite agent is a composition of polyimide, boron nitride and SEBS, with a mass ratio of 1:1:8.

[0069] Comparative Example 4

[0070] This comparative example differs from Example 1 only in the following ways:

[0071] The heat-resistant composite agent is a composition of polyimide, boron nitride and SEBS, with a mass ratio of 8:0.5:1.5.

[0072] Comparative Example 5

[0073] This comparative example differs from Example 1 only in the following ways:

[0074] The preparation method of the functional resin specifically comprises the following steps, calculated by mass: S1: adding 6.8 parts of a base resin to 30 parts of xylene, stirring and swelling at 75°C and 120 rpm for 3 hours, then sequentially adding 1.5 parts of trifluoroethyl acrylate and 1.2 parts of butyl acrylate, and introducing nitrogen for protection; S2: heating to 90°C, adding 0.05 parts of diisopropylbenzene oxide, and then keeping the temperature for reaction for 7 hours; S3: after the reaction is completed, cooling the reaction solution to 50°C, adding methanol 6 times the volume of the reaction solution for precipitation, filtering, washing with acetone and deionized water 3 times each, and vacuum drying at 70°C until the moisture content is ≤0.2wt%.

[0075] Comparative Example 6

[0076] This comparative example differs from Example 1 only in the following ways:

[0077] The preparation method of the functional resin specifically comprises the following steps, calculated by mass: S1: adding 10.5 parts of a base resin to 30 parts of xylene, stirring and swelling at 75°C and 120 rpm for 3 hours, then sequentially adding 0.4 parts of trifluoroethyl acrylate, 1.8 parts of N-acryloylmorpholine and 0.2 parts of trimethylolpropane triacrylate, and introducing nitrogen for protection; S2: heating to 90°C, adding 0.05 parts of diisopropylbenzene oxide, and then keeping the temperature for reaction for 7 hours; S3: after the reaction is completed, cooling the reaction solution to 50°C, adding methanol 6 times the volume of the reaction solution for precipitation, filtering, washing with acetone and deionized water 3 times each, and vacuum drying at 70°C to obtain the product.

[0078] Performance Testing

[0079] 1. Electrical insulation: Test reference standard GB / T 1410, sample thickness:

[0080] 2.0±0.1mm, test voltage: 500V DC, environment: 23℃ / 50%RH, the test results are the average of 10 tests and recorded in Table 1.

[0081] 2. Temperature resistance: The test reference standard is ASTM D648, load: 1.82 MPa, heating rate: 2°C / min, and the test results are the average of 10 tests and recorded in Table 1.

[0082] 3. Aging resistance: The test reference standard IEC 60216-2, temperature: 150 ° C, time: 1000 h, obtain the tensile strength of the surface material before and after the test, calculate the tensile strength retention rate after the test, and take the average of 10 tests as the test results and record them in Table 1.

[0083] 4. Waterproofness: Test reference standard ASTM D570, immersion time: 96h, 23-26℃ deionized water, sample thickness: 2.0±0.1mm, obtain water absorption rate, and take the average value of 10 tests and record it in Table 1.

[0084] Table 1 Performance test results of embodiments and comparative examples

[0085]

[0086] Judging from the final performance test results of the embodiments and comparative examples, comparative examples 1 to 6 achieved worse performance results than the embodiments, while the embodiments, through a better technical solution, produced a functional resin with better performance and worked together with a heat-resistant composite agent, which not only promoted internal covalent cross-linking and hydrogen bond formation, but also used polyimide powder as a rigid reinforcement island to improve the modulus through a mechanical interlocking effect, and at the same time, through the action of boron nitride and SEBS, orientedly arranged along the extrusion direction to form a heat conduction path, thereby helping to improve the temperature resistance, and increasing the diffusion resistance and path of water molecules and corrosion molecules inside the surface material, thereby comprehensively improving the overall material performance.

Claims

1. An overhead insulated cable sheath material, characterized by: Calculated by mass, the raw materials include: 40 to 60 parts of ethylene-vinyl acetate copolymer, 8 to 16 parts of heat-resistant combination agent, and 20 to 35 parts of functional resin; The preparation method of the functional resin comprises the following steps: S1: adding a base resin to an organic solvent, stirring and swelling the base resin, and sequentially adding trifluoroethyl acrylate, N-acryloylmorpholine, and trimethylolpropane triacrylate; S2: heating the base resin and adding dicumyl peroxide, and then maintaining the temperature for reaction; S3: after the reaction is completed, cooling the reaction solution, adding methanol for precipitation, filtering, washing, and drying the base resin; The mass ratio of the base resin, trifluoroethyl acrylate, N-acryloylmorpholine and trimethylolpropane triacrylate is (6-8): (1.2-1.8): (1-1.2): (0.3-0.6).

2. The overhead insulated cable sheath material according to claim 1, characterized in that: The melt index of the ethylene-vinyl acetate copolymer is 1.5-3 g / 10 min, and the conditions are: 2.16 kg, 190° C.

3. The surface material of the overhead insulated cable according to claim 2, characterized in that: The vinyl acetate content of the ethylene-vinyl acetate copolymer is 20-35 wt%.

4. The overhead insulated cable sheath material according to claim 3, characterized in that: The mass ratio of the ethylene-vinyl acetate copolymer, the heat-resistant composite agent and the functional resin is (45-56): (10-14): (25-32).

5. The surface material of the overhead insulated cable according to claim 4, characterized in that: The matrix resin is an ethylene-vinyl acetate copolymer resin with a vinyl acetate content of 12 to 18 wt%.

6. The overhead insulated cable sheath material according to claim 5, characterized in that: The heat-resistant composite agent is a composition of polyimide, boron nitride and SEBS, with a mass ratio of (3-4): (4-4.5): (5-7).

7. The overhead insulated cable sheath material according to claim 6, characterized in that: The average flake diameter of the boron nitride is 150-300 nm; the average particle diameter of the polyimide powder is 2-4 μm.

8. The overhead insulated cable sheath material according to claim 7, characterized in that: Calculated by mass, the raw materials also include: 0.6 to 1.2 parts of antioxidant, 1 to 1.8 parts of ultraviolet absorber, 6 to 10 parts of flame retardant, 1 to 2.5 parts of lubricant, 0.3 to 0.8 parts of coupling agent, and 0.4 to 0.8 parts of anti-hydrolysis agent.

9. The overhead insulated cable sheath material according to claim 8, characterized in that: The coupling agent is at least one of a titanate coupling agent, an aluminate coupling agent and a phosphate coupling agent; and the anti-hydrolysis agent is at least one of phenyl glycidyl ether, triphenyl phosphite and an oxazoline derivative.

10. A method for preparing the surface material of an overhead insulated cable according to any one of claims 1 to 9, characterized in that: The specific steps include: S1: Add ethylene-vinyl acetate copolymer, functional resin and heat-resistant combination agent into a high-speed mixer, control the speed to 1000-1200 rpm, and then add the remaining raw materials in sequence, with an interval of 2-3 minutes each time, and mix for 10-15 minutes each time; S2: Add to an internal mixer and mix at 120-125℃ for 4-6 minutes in the first stage, and at 140-145℃ for 10-12 minutes in the second stage; S3: After the internal mixing is completed, add to a twin-screw extruder for extrusion, with a temperature range of 130-140℃ and a speed of 100-150 rpm. After completion, the product is calendered and formed using a three-roll calender to obtain the product.

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