A heat-resistant aerial insulated cable and a preparation process thereof

Abstract

This invention relates to the field of cable technology and proposes a heat-resistant overhead insulated cable and its manufacturing process. The heat-resistant overhead insulated cable includes a conductor, a shielding layer, and an insulation layer arranged sequentially from the inside out. The insulation layer comprises the following components by weight: 100 parts polyvinyl chloride, 5-8 parts chlorinated polyethylene, 30-40 parts plasticizer, 4-5 parts stabilizer, 10-15 parts filler, 1-3 parts antioxidant, 2-4 parts lubricant, and 8-10 parts phenylmaleimide compound. The phenylmaleimide compound is composed of 2,4,6-trichlorophenylmaleimide and N-phenylmaleimide in a mass ratio of 1:1.5-2. The heat-resistant overhead insulated cable provided by this invention solves the technical problems of insufficient heat resistance, easy softening and deformation at high temperatures, low mechanical property retention after long-term thermal aging, and easy brittle fracture in existing overhead insulated cables.

Description

Technical Field

[0001] This invention relates to the field of cable technology, specifically to a heat-resistant overhead insulated cable and its manufacturing process. Background Technology

[0002] Overhead insulated cables are widely used in urban power distribution networks, rural power grid upgrades, and regional power supply networks for industrial and mining enterprises. Compared to traditional conductors, overhead insulated cables have advantages such as convenient installation and less space occupation, making them an important carrier on the distribution side of modern power systems.

[0003] Currently, the insulation layers of most overhead insulated cables on the market are made of polyvinyl chloride (PVC) or polyethylene (PE), with PVC being widely used due to its low cost, good flame retardancy, and excellent electrical properties. However, with the increase in urban and rural power grid loads and the increasing complexity of the operating environment, traditional PVC insulated cables have revealed shortcomings in heat resistance in practical applications.

[0004] Overhead insulated cables with insufficient heat resistance are prone to softening and deformation of the insulation layer during high-temperature periods in summer or under overload conditions, resulting in thinning of the insulation thickness or even cracking, which seriously threatens the safety of power grid operation. Under long-term thermo-oxidative aging, the polyvinyl chloride molecular chains are prone to releasing hydrogen chloride, causing the material to harden and become brittle, making it prone to powdering and cracking, which significantly shortens the service life of the cable.

[0005] Therefore, improving the temperature resistance of overhead insulated cables is an urgent problem to be solved. Summary of the Invention

[0006] To address the above technical problems, this invention provides a heat-resistant overhead insulated cable and its manufacturing process. The overhead insulated cable provided by this invention has excellent temperature resistance, solving the problems of insufficient heat resistance, easy softening and deformation at high temperatures, low mechanical property retention rate after long-term thermal aging, and easy brittle fracture of existing cables.

[0007] The specific technical solution of the present invention is as follows: According to one aspect of the present invention, a heat-resistant overhead insulated cable is provided, comprising a conductor, a shielding layer, and an insulation layer arranged sequentially from the inside out. The insulation layer comprises the following components in parts by weight: 100 parts polyvinyl chloride, 5-8 parts chlorinated polyethylene, 30-40 parts plasticizer, 4-5 parts stabilizer, 10-15 parts filler, 1-3 parts antioxidant, 2-4 parts lubricant, and 8-10 parts phenylmaleimide compound, wherein the phenylmaleimide compound is composed of 2,4,6-trichlorophenylmaleimide and N-phenylmaleimide in a mass ratio of 1:1.5-2.

[0008] In the above technical solution, the material of the conductor includes one of copper and aluminum alloy.

[0009] In the above technical solution, the chlorine content of the chlorinated polyethylene is 35wt%~36wt%.

[0010] In the above technical solution, the plasticizer includes one or two of tricresyl phosphate and trioctyl trimellitate.

[0011] In the above technical solution, the stabilizer is a calcium-zinc stabilizer.

[0012] In the above technical solution, the antioxidant includes one or more of antioxidant 1010, antioxidant 168, and antioxidant 1076.

[0013] In the above technical solution, the lubricant includes one or more of stearic acid, polyethylene wax, and oxidized polyethylene wax.

[0014] In the above technical solution, the raw materials of the filler include 4-6 parts of carbon black, 80-90 parts of calcined kaolin, 4-5 parts of N-(4-hydroxyphenyl)maleimide, and 2-3 parts of γ-aminopropyltriethoxysilane.

[0015] In the above technical solution, the preparation process of the filler includes the following steps: dispersing N-(4-hydroxyphenyl)maleimide and γ-aminopropyltriethoxysilane in a solvent, adding the carbon black and the calcined kaolin, mixing and drying to obtain the filler.

[0016] According to another aspect of the present invention, the present invention also provides a manufacturing process for the above-mentioned heat-resistant overhead insulated cable, comprising the following steps: S1. The shielding layer is wrapped around the conductor to obtain a semi-finished product; S2. The polyvinyl chloride, chlorinated polyethylene, plasticizer, stabilizer, filler, antioxidant, lubricant, and phenylmaleimide compound are mixed and extruded onto the semi-finished product to obtain the heat-resistant overhead insulated cable.

[0017] Compared with existing technologies, this invention provides a heat-resistant overhead insulated cable. By compounding 2,4,6-trichlorophenylmaleimide and N-phenylmaleimide in a mass ratio of 1:1.5~2, and synergistically combining them with chlorinated polyethylene, the heat resistance of the overhead insulated cable is improved. Specifically, the use of 2,4,6-trichlorophenylmaleimide and N-phenylmaleimide introduces a five-membered imide ring and benzene ring structure into the polyvinyl chloride matrix, increasing the rigidity of the molecular chain and raising the starting temperature for chain segment movement. The added chlorinated polyethylene molecular chain contains both flexible segments and polar chlorine atoms similar to polyvinyl chloride, which can effectively restrain the slippage of the molecular chain, inhibit the thermal deformation of the material, and enhance the interaction force between the components, reducing interface defects caused by high temperatures, thereby improving the heat resistance of the overhead insulated cable. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention more apparent, the invention is described in detail below. It should be understood that the invention is not limited to the description herein.

[0019] Polyvinyl chloride The polyvinyl chloride used in this invention is the polyvinyl chloride known in the art that can be used in cables. In the heat-resistant overhead insulated cable of this invention, polyvinyl chloride serves as the base resin of the insulation layer. Plasticizers, stabilizers, fillers, etc., all need to be dispersed in the polyvinyl chloride matrix. Polyvinyl chloride also provides the necessary melt strength and plasticizing properties to ensure that the cable can be formed through the extrusion process.

[0020] Chlorinated polyethylene The chlorinated polyethylene used in this invention is a known type of chlorinated polyethylene that can be used in cables. In the heat-resistant overhead insulated cable of this invention, the role of chlorinated polyvinyl chloride is as a toughening modifier and a heat-resistant synergistic component of the insulation layer. Its core function is to solve the material embrittlement problem caused by the introduction of rigid heat-resistant monomers into polyvinyl chloride without sacrificing heat resistance, thereby achieving a balance between rigidity and toughness of the insulation layer in high-temperature environments.

[0021] plasticizer The plasticizer used in this invention is a plasticizer known in the art that can be used in cables, and this invention is not limited to the plasticizers listed below. For example, the plasticizer may be one or two of tricresyl phosphate and trioctyl trimellitate. In the heat-resistant overhead insulated cable of this invention, the role of the plasticizer is to reduce the melt viscosity to promote processing, and through its high boiling point and low migration characteristics, it imparts flexibility to the insulation layer while ensuring that the material does not volatilize or leach under long-term high-temperature operating conditions, thereby maintaining the mechanical integrity, heat resistance stability and electrical insulation performance of the insulation layer.

[0022] stabilizer The stabilizer used in this invention is a stabilizer known in the art that can be used in cables, and this invention is not limited to the stabilizers listed below. For example, the stabilizer may be one or two of organotin stabilizers and calcium-zinc stabilizers. In the heat-resistant overhead insulated cable of this invention, the stabilizer plays a role in inhibiting the thermal degradation reaction of polyvinyl chloride at high temperatures, preventing material discoloration, brittleness and deterioration of electrical properties caused by molecular chain breakage, thereby ensuring the reliability of the cable in long-term high-temperature operating environments.

[0023] filler The filler used in this invention is a filler known in the art that can be used in cables, and this invention is not limited to the fillers listed below. For example, the filler may be one or more of carbon black, calcined kaolin, talc, and calcium carbonate. In the heat-resistant overhead insulated cable of this invention, the filler includes carbon black, calcined kaolin, N-(4-hydroxyphenyl)maleimide, and γ-aminopropyltriethoxysilane. Carbon black and kaolin provide a rigid and thermally stable skeleton. N-(4-hydroxyphenyl)maleimide and γ-aminopropyltriethoxysilane can improve the dispersion uniformity of kaolin and carbon black, and also enhance the interfacial adhesion between the filler and the resin. At the same time, N-(4-hydroxyphenyl)maleimide can also introduce heat-resistant groups, further improving the heat resistance of the overhead insulated cable.

[0024] The preparation process of the filler in this invention includes the following steps: dispersing N-(4-hydroxyphenyl)maleimide and γ-aminopropyltriethoxysilane in a solvent, the solvent being composed of water and ethanol in a mass ratio of 1:10, adding carbon black and calcined kaolin, mixing for 2-3 hours and then drying, the mass ratio of carbon black and calcined kaolin to the solvent being 5:1, to obtain the filler.

[0025] antioxidants The antioxidant used in this invention is an antioxidant known in the art that can be used in cables. However, this invention is not limited to the antioxidants listed below. For example, the antioxidant may be one or more of antioxidants 1010, antioxidant 168, and antioxidant 1076. In the heat-resistant overhead insulated cable of this invention, the antioxidant's role is to capture and remove free radical intermediates initiated by heat or light, block free radical chain reactions, prevent molecular chain breakage, cross-linking and discoloration, and inhibit the thermo-oxidative aging and ultraviolet oxidative degradation of polyvinyl chloride and chlorinated polyethylene matrix under high-temperature processing and long-term overhead operation environment, thereby maintaining the service life of the insulation layer under long-term high-temperature environment.

[0026] lubricant The lubricant used in this invention is a lubricant known in the art that can be used for cables, and this invention is not limited to the lubricants listed below. For example, the lubricant may be one or more of stearic acid, polyethylene wax, and oxidized polyethylene wax. In the heat-resistant overhead insulated cable of this invention, the function of the lubricant is to adjust the melt rheology of the polyvinyl chloride and chlorinated polyethylene blend system during the processing, reduce the frictional resistance between the melt and the metal surface of the equipment, prevent thermal degradation and melt fracture under high temperature shear, ensure that the surface of the insulation layer is smooth and dense, and at the same time avoid the decrease in insulation strength caused by excessive lubricant.

[0027] A heat-resistant overhead insulated cable The heat-resistant overhead insulated cable of the present invention comprises a conductor, a shielding layer, and an insulation layer arranged sequentially from the inside to the outside; In the insulation layer, the weight percentage of polyvinyl chloride is 100 parts; The chlorinated polyethylene is in the form of 5 to 8 parts by weight, preferably 6 to 7 parts; The plasticizer is present in 30 to 40 parts by weight, preferably 32 to 38 parts, and more preferably 34 to 36 parts by weight. The stabilizer is present in 4 to 5 parts by weight, preferably 4.4 to 4.6 parts by weight; The filler is 10 to 15 parts by weight, preferably 11 to 14 parts, and more preferably 12 to 13 parts; The antioxidant is present in 1 to 3 parts by weight, preferably 1.5 to 2.5 parts; The lubricant is present in 2 to 4 parts by weight, preferably 2.5 to 3.5 parts by weight; The phenylmaleimide compound is present in 8 to 10 parts by weight, preferably 8.5 to 9.5 parts by weight.

[0028] Manufacturing process of heat-resistant overhead insulated cables The present invention also provides a method for preparing the aforementioned heat-resistant overhead insulated cable, comprising: S1. Wrap the shielding layer around the conductor to obtain a semi-finished product; S2. Mix polyvinyl chloride, chlorinated polyethylene, plasticizer, stabilizer, filler, antioxidant, lubricant, and phenylmaleimide compound, and extrude the mixture onto the semi-finished product to obtain a heat-resistant overhead insulated cable.

[0029] To further illustrate the present invention, the following examples will provide a detailed description. The raw materials used in the following examples and comparative examples of the present invention are all commercially available products. Specifically, the polyvinyl chloride (PVC) is type S-70; the chlorinated polyethylene (CPE) is type CPE CM3630E with a chlorine content of 36 wt%; the carbon black has an average particle size of 800 mesh; the calcined kaolin has an average particle size of 400 mesh; and the calcium-zinc stabilizer is type SONGSTAB CZ-SC490.

[0030] Example 1 A method for producing a heat-resistant overhead insulated cable includes the following steps: S1. Wrap the shielding layer around the copper conductor to obtain a semi-finished product; S2. Mix 100 parts of polyvinyl chloride, 5 parts of chlorinated polyethylene, 30 parts of trioctyl trimellitate, 4 parts of calcium zinc stabilizer, 10 parts of filler, 1 part of antioxidant 1010, 2 parts of stearic acid, and 8 parts of phenylmaleimide compound, and extrude the mixture onto the semi-finished product to obtain a heat-resistant overhead insulated cable. The preparation process of the filler includes the following steps: 6 parts of γ-aminopropyltriethoxysilane are dispersed in 420 parts of solvent, the solvent is composed of water and ethanol in a mass ratio of 1:10, 4 parts of carbon black and 80 parts of calcined kaolin are added, and after mixing for 2 hours, the mixture is dried to obtain the filler; The phenylmaleimide compound is composed of 2,4,6-trichlorophenylmaleimide and N-phenylmaleimide in a mass ratio of 1:2.

[0031] Example 2 A method for producing a heat-resistant overhead insulated cable includes the following steps: S1. Wrap the shielding layer around the copper conductor to obtain a semi-finished product; S2. Mix 100 parts of polyvinyl chloride, 6 parts of chlorinated polyethylene, 35 parts of trioctyl trimellitate, 4.5 parts of calcium zinc stabilizer, 12 parts of filler, 2 parts of antioxidant 168, 3 parts of stearic acid, and 9 parts of phenyl maleimide compound, and extrude the mixture onto the semi-finished product to obtain a heat-resistant overhead insulated cable. The preparation process of the filler includes the following steps: 6 parts of γ-aminopropyltriethoxysilane are dispersed in 450 parts of solvent, the solvent is composed of water and ethanol in a mass ratio of 1:10, 5 parts of carbon black and 85 parts of calcined kaolin are added, and after mixing for 2 hours, the mixture is dried to obtain the filler. The phenylmaleimide compound is composed of 2,4,6-trichlorophenylmaleimide and N-phenylmaleimide in a mass ratio of 1:2.

[0032] Example 3 A method for producing a heat-resistant overhead insulated cable includes the following steps: S1. Wrap the shielding layer around the copper conductor to obtain a semi-finished product; S2. Mix 100 parts of polyvinyl chloride, 8 parts of chlorinated polyethylene, 40 parts of trioctyl trimellitate, 5 parts of calcium zinc stabilizer, 15 parts of filler, 3 parts of antioxidant 1076, 4 parts of stearic acid, and 10 parts of phenyl maleimide compound, and extrude the mixture onto the semi-finished product to obtain a heat-resistant overhead insulated cable. The preparation process of the filler includes the following steps: 7 parts of γ-aminopropyltriethoxysilane are dispersed in 480 parts of solvent, the solvent is composed of water and ethanol in a mass ratio of 1:10, 6 parts of carbon black and 90 parts of calcined kaolin are added, and after mixing for 3 hours, the mixture is dried to obtain the filler; The phenylmaleimide compound is composed of 2,4,6-trichlorophenylmaleimide and N-phenylmaleimide in a mass ratio of 1:2.

[0033] Example 4 A method for producing a heat-resistant overhead insulated cable includes the following steps: S1. Wrap the shielding layer around the copper conductor to obtain a semi-finished product; S2. Mix 100 parts of polyvinyl chloride, 6 parts of chlorinated polyethylene, 35 parts of trioctyl trimellitate, 4.5 parts of calcium zinc stabilizer, 12 parts of filler, 2 parts of antioxidant 168, 3 parts of stearic acid, and 9 parts of phenyl maleimide compound, and extrude the mixture onto the semi-finished product to obtain a heat-resistant overhead insulated cable. The preparation process of the filler includes the following steps: 6 parts of γ-aminopropyltriethoxysilane are dispersed in 450 parts of solvent, the solvent is composed of water and ethanol in a mass ratio of 1:10, 5 parts of carbon black and 85 parts of calcined kaolin are added, and after mixing for 2 hours, the mixture is dried to obtain the filler. The phenylmaleimide compound consists of 2,4,6-trichlorophenylmaleimide and N-phenylmaleimide in a mass ratio of 1.5:2.

[0034] Example 5 A method for producing a heat-resistant overhead insulated cable includes the following steps: S1. Wrap the shielding layer around the copper conductor to obtain a semi-finished product; S2. Mix 100 parts of polyvinyl chloride, 6 parts of chlorinated polyethylene, 35 parts of trioctyl trimellitate, 4.5 parts of calcium zinc stabilizer, 12 parts of filler, 2 parts of antioxidant 168, 3 parts of stearic acid, and 9 parts of phenyl maleimide compound, and extrude the mixture onto the semi-finished product to obtain a heat-resistant overhead insulated cable. The preparation process of the filler includes the following steps: 6 parts of N-(4-hydroxyphenyl)maleimide are dispersed in 450 parts of solvent, the solvent is composed of water and ethanol in a mass ratio of 1:10, 5 parts of carbon black and 85 parts of calcined kaolin are added, and the mixture is dried after 2 hours to obtain the filler; The phenylmaleimide compound consists of 2,4,6-trichlorophenylmaleimide and N-phenylmaleimide in a mass ratio of 1.5:2.

[0035] Example 6 A method for producing a heat-resistant overhead insulated cable includes the following steps: S1. Wrap the shielding layer around the copper conductor to obtain a semi-finished product; S2. Mix 100 parts of polyvinyl chloride, 6 parts of chlorinated polyethylene, 35 parts of trioctyl trimellitate, 4.5 parts of calcium zinc stabilizer, 12 parts of filler, 2 parts of antioxidant 168, 3 parts of stearic acid, and 9 parts of phenyl maleimide compound, and extrude the mixture onto the semi-finished product to obtain a heat-resistant overhead insulated cable. The preparation process of the filler includes the following steps: 2 parts of γ-aminopropyltriethoxysilane and 4 parts of N-(4-hydroxyphenyl)maleimide are dispersed in 450 parts of solvent, the solvent is composed of water and ethanol in a mass ratio of 1:10, 5 parts of carbon black and 85 parts of calcined kaolin are added, and after mixing for 2 hours, the mixture is dried to obtain the filler. The phenylmaleimide compound consists of 2,4,6-trichlorophenylmaleimide and N-phenylmaleimide in a mass ratio of 1.5:2.

[0036] Example 7 A method for producing a heat-resistant overhead insulated cable includes the following steps: S1. Wrap the shielding layer around the copper conductor to obtain a semi-finished product; S2. Mix 100 parts of polyvinyl chloride, 6 parts of chlorinated polyethylene, 35 parts of trioctyl trimellitate, 4.5 parts of calcium zinc stabilizer, 12 parts of filler, 2 parts of antioxidant 168, 3 parts of stearic acid, and 9 parts of phenyl maleimide compound, and extrude the mixture onto the semi-finished product to obtain a heat-resistant overhead insulated cable. The preparation process of the filler includes the following steps: 3 parts of γ-aminopropyltriethoxysilane and 5 parts of N-(4-hydroxyphenyl)maleimide are dispersed in 450 parts of solvent, the solvent is composed of water and ethanol in a mass ratio of 1:10, 5 parts of carbon black and 85 parts of calcined kaolin are added, and after mixing for 2 hours, the mixture is dried to obtain the filler. The phenylmaleimide compound consists of 2,4,6-trichlorophenylmaleimide and N-phenylmaleimide in a mass ratio of 1.5:2.

[0037] Example 8 A method for producing a heat-resistant overhead insulated cable includes the following steps: S1. Wrap the shielding layer around the copper conductor to obtain a semi-finished product; S2. Mix 100 parts of polyvinyl chloride, 6 parts of chlorinated polyethylene, 35 parts of trioctyl trimellitate, 4.5 parts of calcium zinc stabilizer, 12 parts of filler, 2 parts of antioxidant 168, 3 parts of stearic acid, and 9 parts of phenyl maleimide compound, and extrude the mixture onto the semi-finished product to obtain a heat-resistant overhead insulated cable. The preparation process of the filler includes the following steps: 3 parts of γ-aminopropyltriethoxysilane and 5 parts of N-(2-hydroxyethyl)maleimide are dispersed in 450 parts of solvent, the solvent is composed of water and ethanol in a mass ratio of 1:10, 5 parts of carbon black and 85 parts of calcined kaolin are added, and after mixing for 2 hours, the mixture is dried to obtain the filler. The phenylmaleimide compound consists of 2,4,6-trichlorophenylmaleimide and N-phenylmaleimide in a mass ratio of 1.5:2.

[0038] Comparative Example 1 A method for producing a heat-resistant overhead insulated cable includes the following steps: S1. Wrap the shielding layer around the copper conductor to obtain a semi-finished product; S2. Mix 100 parts of polyvinyl chloride, 6 parts of chlorinated polyethylene, 35 parts of trioctyl trimellitate, 4.5 parts of calcium zinc stabilizer, 12 parts of filler, 2 parts of antioxidant 168, 3 parts of stearic acid, and 9 parts of phenyl maleimide compound, and extrude the mixture onto the semi-finished product to obtain a heat-resistant overhead insulated cable. The preparation process of the filler includes the following steps: 6 parts of γ-aminopropyltriethoxysilane are dispersed in 450 parts of solvent, the solvent is composed of water and ethanol in a mass ratio of 1:10, 5 parts of carbon black and 85 parts of calcined kaolin are added, and after mixing for 2 hours, the mixture is dried to obtain the filler. The phenylmaleimide compound is 2,4,6-trichlorophenylmaleimide.

[0039] Comparative Example 2 A method for producing a heat-resistant overhead insulated cable includes the following steps: S1. Wrap the shielding layer around the copper conductor to obtain a semi-finished product; S2. Mix 100 parts of polyvinyl chloride, 6 parts of chlorinated polyethylene, 35 parts of trioctyl trimellitate, 4.5 parts of calcium zinc stabilizer, 12 parts of filler, 2 parts of antioxidant 168, 3 parts of stearic acid, and 9 parts of phenyl maleimide compound, and extrude the mixture onto the semi-finished product to obtain a heat-resistant overhead insulated cable. The preparation process of the filler includes the following steps: 6 parts of γ-aminopropyltriethoxysilane are dispersed in 450 parts of solvent, the solvent is composed of water and ethanol in a mass ratio of 1:10, 5 parts of carbon black and 85 parts of calcined kaolin are added, and after mixing for 2 hours, the mixture is dried to obtain the filler. The phenylmaleimide compound is N-phenylmaleimide.

[0040] Comparative Example 3 A method for producing a heat-resistant overhead insulated cable includes the following steps: S1. Wrap the shielding layer around the copper conductor to obtain a semi-finished product; S2. Mix 100 parts of polyvinyl chloride, 6 parts of chlorinated polyethylene, 35 parts of trioctyl trimellitate, 4.5 parts of calcium zinc stabilizer, 12 parts of filler, 2 parts of antioxidant 168, 3 parts of stearic acid, and 9 parts of phenyl maleimide compound, and extrude the mixture onto the semi-finished product to obtain a heat-resistant overhead insulated cable. The preparation process of the filler includes the following steps: 6 parts of γ-aminopropyltriethoxysilane are dispersed in 450 parts of solvent, the solvent is composed of water and ethanol in a mass ratio of 1:10, 5 parts of carbon black and 85 parts of calcined kaolin are added, and after mixing for 2 hours, the mixture is dried to obtain the filler. The phenylmaleimide compound is composed of N-(4-hydroxyphenyl)maleimide and N-phenylmaleimide in a mass ratio of 1:2.

[0041] Performance testing After conducting the heat aging test according to GB / T 7141-2008 "Plastics - Test Method for Heat Aging", the tensile strength before and after heat aging was tested according to the test method specified in GB / T1040.1-2018 "Determination of Tensile Properties of Plastics - Part 1: General". The average value of 5 samples was used as the result value, and the test speed was 200 mm / min. The heat aging test was conducted using Method B, with a temperature of 90℃ and a time of 128 h.

[0042] The performance of each embodiment and comparative example after testing is shown in Table 1.

[0043] Table 1 Performance test results of the examples and comparative examples

[0044] As shown in Table 1, comparing Example 2 with Comparative Examples 1 and 2, it can be seen that when the phenylmaleimide compound is composed of 2,4,6-trichlorophenylmaleimide and N-phenylmaleimide, the two work synergistically to improve the heat resistance of overhead insulated cables. In Comparative Example 3, 2,4,6-trichlorophenylmaleimide was replaced with an equal amount of N-(4-hydroxyphenyl)maleimide. As a result, the performance of Comparative Example 3 was lower than that of Example 2, indicating that the addition of chlorine in 2,4,6-trichlorophenylmaleimide played a role in improving the heat resistance.

[0045] A comparison of Examples 6, 7, and 4 shows that when the filler contains both γ-aminopropyltriethoxysilane and N-(4-hydroxyphenyl)maleimide, the heat resistance of overhead insulated cables can be improved. In Example 8, N-(4-hydroxyphenyl)maleimide was replaced with an equal amount of N-(2-hydroxyethyl)maleimide. As a result, the heat resistance of Example 8 was lower than that of Example 7, indicating that the phenyl group in N-(4-hydroxyphenyl)maleimide contributed to the improvement of heat resistance.

[0046] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A heat-resistant overhead insulated cable, comprising a conductor, a shielding layer, and an insulation layer arranged sequentially from the inside out, characterized in that, The insulating layer comprises the following components in parts by weight: 100 parts polyvinyl chloride, 5-8 parts chlorinated polyethylene, 30-40 parts plasticizer, 4-5 parts stabilizer, 10-15 parts filler, 1-3 parts antioxidant, 2-4 parts lubricant, and 8-10 parts phenylmaleimide compound, wherein the phenylmaleimide compound is composed of 2,4,6-trichlorophenylmaleimide and N-phenylmaleimide in a mass ratio of 1:1.5-2.

2. The heat-resistant overhead insulated cable according to claim 1, characterized in that, The conductor is made of either copper or aluminum alloy.

3. The heat-resistant overhead insulated cable according to claim 1, characterized in that, The chlorine content of the chlorinated polyethylene is 35wt%~36wt%.

4. The heat-resistant overhead insulated cable according to claim 1, characterized in that, The plasticizer includes one or both of tricresyl phosphate and trioctyl trimellitate.

5. A heat-resistant overhead insulated cable according to claim 1, characterized in that, The stabilizer is a calcium-zinc stabilizer.

6. A heat-resistant overhead insulated cable according to claim 1, characterized in that, The antioxidant includes one or more of antioxidant 1010, antioxidant 168, and antioxidant 1076.

7. A heat-resistant overhead insulated cable according to claim 1, characterized in that, The lubricant includes one or more of stearic acid, polyethylene wax, and oxidized polyethylene wax.

8. A heat-resistant overhead insulated cable according to claim 1, characterized in that, The raw materials for the filler include 4-6 parts of carbon black, 80-90 parts of calcined kaolin, 4-5 parts of N-(4-hydroxyphenyl)maleimide, and 2-3 parts of γ-aminopropyltriethoxysilane.

9. A heat-resistant overhead insulated cable according to claim 8, characterized in that, The preparation process of the filler includes the following steps: dispersing N-(4-hydroxyphenyl)maleimide and γ-aminopropyltriethoxysilane in a solvent, adding the carbon black and the calcined kaolin, mixing and drying to obtain the filler.

10. A manufacturing process for a heat-resistant overhead insulated cable, used to manufacture the heat-resistant overhead insulated cable according to any one of claims 1 to 9, characterized in that, Includes the following steps: S1. The shielding layer is wrapped around the conductor to obtain a semi-finished product; S2. The polyvinyl chloride, chlorinated polyethylene, plasticizer, stabilizer, filler, antioxidant, lubricant, and phenylmaleimide compound are mixed and extruded onto the semi-finished product to obtain the heat-resistant overhead insulated cable.

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