An aging-resistant power cable

Abstract

This invention relates to the field of cable technology and proposes an aging-resistant power cable. From the inside out, it comprises a cable core and a sheath layer. The cable core is formed by stranding multiple insulated wires, and the insulated wires include a conductor bundle and an insulating layer covering the outside of the conductor bundle. The sheath layer comprises the following raw materials: polyethylene, inorganic filler, flame retardant, and compatibilizer. The aging-resistant power cable provided by this invention has high mechanical properties and good aging resistance in its sheath layer, solving the technical problem that the aging resistance effect of existing power cable sheath layers is not as expected.

Description

Technical Field

[0001] This invention relates to the field of cable technology, and more specifically, to an aging-resistant power cable. Background Technology

[0002] As the carrier of electrical energy, the long-term reliability of power cables is crucial. The cable sheath is the first line of defense protecting the internal conductive cores and insulation from external environmental factors such as sunlight, ozone, heat, chemical agents, and mechanical stress. Therefore, the aging resistance of the sheath directly determines the cable's service life and long-term safety.

[0003] To improve the aging resistance of the sheath layer, the industry commonly uses the method of adding various functional fillers to the polymer matrix. For example, carbon black is added to improve aging resistance.

[0004] However, in actual production and use, it has been found that the long-term aging resistance performance of cable sheaths prepared by existing technologies is often not as good as expected. The core reason is that the functional inorganic fillers in the sheath material are difficult to achieve uniform and stable dispersion in the polymer matrix, which leads to the aging resistance performance of power cables being less than expected.

[0005] Therefore, it is necessary to develop a power cable that is resistant to aging. Summary of the Invention

[0006] To address the above technical problems, this invention provides an aging-resistant power cable. The inorganic filler in the sheath layer of the aging-resistant power cable provided by this invention has good dispersion, which greatly improves the aging resistance of the sheath layer and solves the problem that the aging resistance is not as expected due to the poor dispersion of inorganic fillers.

[0007] The specific technical solution of the present invention is as follows: According to one aspect of the present invention, an aging-resistant power cable is provided, comprising, from the inside out, a cable core and a sheath layer. The cable core is formed by stranding multiple insulated wire cores, and the insulated wire core includes a conductor bundle and an insulating layer covering the outside of the conductor bundle. The sheath layer comprises raw materials with the following components: polyethylene, inorganic filler, flame retardant, and compatibilizer.

[0008] In the above technical solution, the conductor bundle is made of 18 to 20 metal wires twisted together.

[0009] In the above technical solution, the insulating layer is a cross-linked polyethylene insulating layer.

[0010] In the above technical solution, the gaps between the insulating wire cores of the cable core are filled with a filling material.

[0011] In the above technical solution, a wrapping layer is provided between the cable core and the sheath layer.

[0012] In the above technical solution, the sheath layer comprises the following raw materials in parts by weight: 100 parts polyethylene, 15-20 parts inorganic filler, 4-6 parts flame retardant, and 6-8 parts compatibilizer; The inorganic filler is composed of carboxylated styrene-butadiene latex modified inorganic filler and hydroxyl acrylic emulsion modified inorganic filler in a mass ratio of 2:1~3.

[0013] In the above technical solution, the preparation method of the carboxylated styrene-butadiene latex modified inorganic filler includes the following steps: after adding carboxylated styrene-butadiene latex to a solvent and dispersing it evenly, adding inorganic filler A and mixing, and then drying to obtain carboxylated styrene-butadiene latex modified inorganic filler; The preparation method of the hydroxy acrylic emulsion modified inorganic filler includes the following steps: after the hydroxy acrylic emulsion is added to a solvent and dispersed evenly, inorganic filler B is added and mixed, and then dried to obtain the hydroxy acrylic emulsion modified inorganic filler.

[0014] In the above technical solution, the melt index of the polyethylene is 2~10g / 10min, and the test conditions are 190℃ and 2.16kg load.

[0015] In the above technical solution, the polyethylene is a composite polyethylene, which is composed of polyethylene with a melt index of 2 to 2.6 g / 10 min and polyethylene with a melt index of 5 to 10 g / 10 min in a mass ratio of 1:2 to 4. The test conditions for the melt index are 190°C and 2.16 kg load.

[0016] In the above technical solution, the inorganic filler includes one or more of montmorillonite, carbon black, and titanium dioxide.

[0017] Compared with existing technologies, this invention provides an aging-resistant power cable. First, the power cable of this invention consists of a cable core and a sheath layer from the inside out. The cable core is composed of multiple strands of insulated wires twisted together, with an insulation layer covering the conductor bundle. The outer layer is a dedicated sheath layer, forming a double barrier of inner insulation protection and outer weather-resistant protection. The inner insulation layer isolates the conductor from external moisture, oxygen, etc. Second, the inorganic filler in the sheath layer acts as a physical shield, absorbing ultraviolet rays and reducing the photodegradation of polyethylene molecular chains by ultraviolet light, thereby improving the aging resistance of the sheath layer. 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] polyethylene The polyethylene used in this invention is the type of polyethylene known in the art for use in cable sheathing layers, and this invention is not limited to the polyethylene listed below. As an example, the polyethylene may be one or both of polyethylene with a melt flow index of 2.6 g / 10 min and polyethylene with a melt flow index of 5 g / 10 min. In the sheathing layer of this invention, the polyethylene serves as the substrate of the sheathing layer, isolating the internal conductors of the power cable from the external environment, preventing leakage and short circuits, providing a certain degree of mechanical protection, and improving the adaptability of the power cable to the application environment.

[0020] Inorganic packing The inorganic filler used in this invention is an inorganic filler known in the art for use in cable sheath layers, and this invention is not limited to the inorganic fillers listed below. As an example, the inorganic filler may be one or more of montmorillonite, carbon black, and titanium dioxide. In the sheath layer of this invention, the inorganic filler serves to improve resistance to ultraviolet aging, enhance the UV resistance of the sheath layer, and further improve the aging resistance of the power cable.

[0021] Flame retardant The flame retardant used in this invention is a known flame retardant in the art that can be used for cable sheathing layers, and this invention is not limited to the flame retardants listed below. As an example, the flame retardant may be one or both of magnesium hydroxide and aluminum hydroxide. In the sheathing layer of this invention, the role of the flame retardant is to improve the flame retardant performance of the sheathing layer and improve the safety level of the power cable.

[0022] compatibilizer The compatibilizer used in this invention is a known compatibilizer in the art for use in cable sheath layers, and this invention is not limited to the compatibilizers listed below. As an example, the compatibilizer can be maleic anhydride-grafted polyethylene. In the sheath layer of this invention, the role of the compatibilizer is to improve the compatibilization between polyethylene and flame retardant in the sheath layer, enhance the tensile strength of the sheath layer, and thus help improve the aging resistance of the power cable.

[0023] An aging-resistant power cable includes, from the inside out, a cable core and a sheath layer. The cable core is made of multiple strands of insulated wire cores twisted together. The insulated wire core includes a conductor bundle and an insulation layer covering the outside of the conductor bundle.

[0024] The sheath layer contains 100 parts by weight of polyethylene and 15-20 parts by weight of inorganic filler, preferably 16-18 parts by weight. The flame retardant contains 4-6 parts by weight, preferably 4.5-5 parts by weight. The compatibilizer contains 6-8 parts by weight, preferably 7-7.5 parts by weight.

[0025] The inorganic filler in the sheath layer consists of carboxylated styrene-butadiene latex modified inorganic filler and hydroxyl acrylic emulsion modified inorganic filler in a mass ratio of 2:1~3, preferably 2:1.5~2.5.

[0026] In the sheath layer, carboxylated styrene-butadiene latex and hydroxyl acrylic emulsion can form hydrogen bonds with the hydroxyl groups on the surface of the inorganic filler. Among them, carboxylated styrene-butadiene latex has excellent compatibility with the polyethylene matrix, while hydroxyl acrylic emulsion has stronger bonding force with the surface of the inorganic filler. However, if the proportion of hydroxyl acrylic emulsion-modified inorganic filler is too low, the surface of the inorganic filler will not be fully coated, and the exposed active groups will easily lead to filler agglomeration, resulting in a decrease in the aging resistance of the sheath layer. If its proportion is too high, the system polarity will be too large, and the compatibility with the non-polar polyethylene matrix will become poor, which will easily lead to interfacial phase separation, resulting in deterioration of the mechanical properties and aging resistance of the sheath. Therefore, the mass ratio of carboxylated styrene-butadiene latex-modified inorganic filler to hydroxyl acrylic emulsion-modified inorganic filler is limited to 2:1~3, which can further improve the mechanical properties and aging resistance of the sheath layer.

[0027] The polyethylene in the sheath layer is a composite polyethylene, which is composed of polyethylene with a melt index of 2 to 2.6 g / 10 min and polyethylene with a melt index of 5 to 10 g / 10 min in a mass ratio of 1:2 to 4. The melt index test conditions are 190℃ and 2.16 kg load.

[0028] The inventors discovered that defining the composition of the composite polyethylene in the sheath layer can better improve the processing performance. Specifically, defining the two types of polyethylene with different melt indices can further improve the mechanical properties of the sheath layer.

[0029] The preparation method of carboxylated styrene-butadiene latex modified inorganic filler in the sheath layer includes the following steps: carboxylated styrene-butadiene latex is added to a solvent and dispersed evenly, then inorganic filler A is added and mixed, and then dried to obtain carboxylated styrene-butadiene latex modified inorganic filler; The preparation method of hydroxy acrylic emulsion modified inorganic filler in the sheath layer includes the following steps: after adding hydroxy acrylic emulsion to a solvent and dispersing it evenly, adding inorganic filler B and mixing, and then drying to obtain hydroxy acrylic emulsion modified inorganic filler.

[0030] 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, including: carboxylated styrene-butadiene latex, product number H-2103, manufactured by Guangzhou Huaweike New Materials Co., Ltd.; hydroxyl acrylic emulsion, product number KL-6650, manufactured by Zhaoqing Xinguangli Chemical Industry Co., Ltd.; polyethylene, model: 608A, low-density polyethylene, melt index 2.6 g / 10 min, Dow Chemical, USA; polyethylene, model: 4206, low-density polyethylene, melt index 5 g / 10 min, Dow Chemical, USA; carbon black, model N330; magnesium hydroxide, average particle size 800 mesh; and maleic anhydride grafted polyethylene, model AMPLIFY™ TY 1053H, Dow Chemical, USA.

[0031] Example 1 A method for preparing an aging-resistant power cable includes the following steps: Twenty copper wires are twisted together to obtain a conductor bundle; an insulation layer is wrapped around the outside of the conductor bundle to obtain an insulated core; four insulated cores are twisted together to obtain a cable core; the gaps between the insulated cores of the cable core are filled with polypropylene filler rope; a wrapping layer is set on the outer layer of the cable core to obtain a semi-finished power cable. A method for preparing carboxylated styrene-butadiene latex modified inorganic filler includes the following steps: Carboxylated styrene-butadiene latex (the amount of carboxylated styrene-butadiene latex added is 6% of the mass of carbon black) is added to 5 times its mass of water and dispersed evenly; carbon black is added and mixed at 40℃ for 1.5 h; after drying, carboxylated styrene-butadiene latex modified inorganic filler is obtained. A method for preparing hydroxyl acrylic emulsion modified inorganic filler includes the following steps: Hydroxy acrylic emulsion (the amount of hydroxyl acrylic emulsion added is 6% of the mass of carbon black) is added to 5 times its mass of water and dispersed evenly; carbon black is added and mixed at 40℃ for 1.5 h; after drying, hydroxyl acrylic emulsion modified inorganic filler is obtained. 100 parts of polyethylene (model: 4206), 15 parts of inorganic filler (composed of carboxylated styrene-butadiene latex modified inorganic filler and hydroxyl acrylic emulsion modified inorganic filler in a mass ratio of 2:1), 4 parts of magnesium hydroxide, and 6 parts of maleic anhydride-grafted polyethylene were mixed evenly to obtain a mixture. The mixture was then melt-extruded in a twin-screw extruder to coat the outside of the semi-finished power cable to form a sheath layer, resulting in an aging-resistant power cable. The operating parameters of the twin-screw extruder were: Zone 1 145℃, Zone 2 155℃, Zone 3 155℃, Zone 4 160℃, Zone 5 160℃, Zone 6 160℃, Zone 7 160℃, Zone 8 155℃, and the screw speed was 110 r / min.

[0032] Example 2 Twenty copper wires are twisted together to obtain a conductor bundle; an insulation layer is wrapped around the outside of the conductor bundle to obtain an insulated core; four insulated cores are twisted together to obtain a cable core; the gaps between the insulated cores of the cable core are filled with polypropylene filler rope; a wrapping layer is set on the outer layer of the cable core to obtain a semi-finished power cable. A method for preparing carboxylated styrene-butadiene latex modified inorganic filler includes the following steps: Carboxylated styrene-butadiene latex (the amount of carboxylated styrene-butadiene latex added is 6% of the mass of carbon black) is added to 5 times its mass of water and dispersed evenly; carbon black is added and mixed at 40℃ for 1.5 h; after drying, carboxylated styrene-butadiene latex modified inorganic filler is obtained. A method for preparing hydroxyl acrylic emulsion modified inorganic filler includes the following steps: Hydroxy acrylic emulsion (the amount of hydroxyl acrylic emulsion added is 6% of the mass of carbon black) is added to 5 times its mass of water and dispersed evenly; carbon black is added and mixed at 40℃ for 1.5 h; after drying, hydroxyl acrylic emulsion modified inorganic filler is obtained. 100 parts of polyethylene (model: 4206), 20 parts of inorganic filler (composed of carboxylated styrene-butadiene latex modified inorganic filler and hydroxyl acrylic emulsion modified inorganic filler in a mass ratio of 2:1), 6 parts of magnesium hydroxide, and 8 parts of maleic anhydride-grafted polyethylene were mixed evenly to obtain a mixture. The mixture was then melt-extruded in a twin-screw extruder to coat the outside of the semi-finished power cable to form a sheath layer, thus obtaining an aging-resistant power cable. The operating parameters of the twin-screw extruder were: Zone 1 145℃, Zone 2 155℃, Zone 3 155℃, Zone 4 160℃, Zone 5 160℃, Zone 6 160℃, Zone 7 160℃, Zone 8 155℃, and the screw speed was 110 r / min.

[0033] Example 3 Twenty copper wires are twisted together to obtain a conductor bundle; an insulation layer is wrapped around the outside of the conductor bundle to obtain an insulated core; four insulated cores are twisted together to obtain a cable core; the gaps between the insulated cores of the cable core are filled with polypropylene filler rope; a wrapping layer is set on the outer layer of the cable core to obtain a semi-finished power cable. A method for preparing carboxylated styrene-butadiene latex modified inorganic filler includes the following steps: Carboxylated styrene-butadiene latex (the amount of carboxylated styrene-butadiene latex added is 6% of the mass of carbon black) is added to 5 times its mass of water and dispersed evenly; carbon black is added and mixed at 40℃ for 1.5 h; after drying, carboxylated styrene-butadiene latex modified inorganic filler is obtained. A method for preparing hydroxyl acrylic emulsion modified inorganic filler includes the following steps: Hydroxy acrylic emulsion (the amount of hydroxyl acrylic emulsion added is 6% of the mass of carbon black) is added to 5 times its mass of water and dispersed evenly; carbon black is added and mixed at 40℃ for 1.5 h; after drying, hydroxyl acrylic emulsion modified inorganic filler is obtained. 100 parts of polyethylene (model: 4206), 20 parts of inorganic filler (composed of carboxylated styrene-butadiene latex modified inorganic filler and hydroxyl acrylic emulsion modified inorganic filler in a mass ratio of 2:3), 6 parts of magnesium hydroxide, and 8 parts of maleic anhydride-grafted polyethylene were mixed evenly to obtain a mixture. The mixture was then melt-extruded in a twin-screw extruder to coat the outside of the semi-finished power cable to form a sheath layer, thus obtaining an aging-resistant power cable. The operating parameters of the twin-screw extruder were: Zone 1 145℃, Zone 2 155℃, Zone 3 155℃, Zone 4 160℃, Zone 5 160℃, Zone 6 160℃, Zone 7 160℃, Zone 8 155℃, and the screw speed was 110 r / min.

[0034] Example 4 Twenty copper wires are twisted together to obtain a conductor bundle; an insulation layer is wrapped around the outside of the conductor bundle to obtain an insulated core; four insulated cores are twisted together to obtain a cable core; the gaps between the insulated cores of the cable core are filled with polypropylene filler rope; a wrapping layer is set on the outer layer of the cable core to obtain a semi-finished power cable. A method for preparing carboxylated styrene-butadiene latex modified inorganic filler includes the following steps: Carboxylated styrene-butadiene latex (the amount of carboxylated styrene-butadiene latex added is 6% of the mass of carbon black) is added to 5 times its mass of water and dispersed evenly; carbon black is added and mixed at 40℃ for 1.5 h; after drying, carboxylated styrene-butadiene latex modified inorganic filler is obtained. A method for preparing hydroxyl acrylic emulsion modified inorganic filler includes the following steps: Hydroxy acrylic emulsion (the amount of hydroxyl acrylic emulsion added is 6% of the mass of carbon black) is added to 5 times its mass of water and dispersed evenly; carbon black is added and mixed at 40℃ for 1.5 h; after drying, hydroxyl acrylic emulsion modified inorganic filler is obtained. 100 parts of polyethylene (model: 4206), 20 parts of inorganic filler (composed of carboxylated styrene-butadiene latex modified inorganic filler and hydroxyl acrylic emulsion modified inorganic filler with a mass ratio of 2:0.5), 6 parts of magnesium hydroxide, and 8 parts of maleic anhydride-grafted polyethylene were mixed evenly to obtain a mixture. The mixture was then melt-extruded in a twin-screw extruder to coat the outside of the semi-finished power cable to form a sheath layer, thus obtaining an aging-resistant power cable. The operating parameters of the twin-screw extruder were: Zone 1 145℃, Zone 2 155℃, Zone 3 155℃, Zone 4 160℃, Zone 5 160℃, Zone 6 160℃, Zone 7 160℃, Zone 8 155℃, and the screw speed was 110 r / min.

[0035] Example 5 Twenty copper wires are twisted together to obtain a conductor bundle; an insulation layer is wrapped around the outside of the conductor bundle to obtain an insulated core; four insulated cores are twisted together to obtain a cable core; the gaps between the insulated cores of the cable core are filled with polypropylene filler rope; a wrapping layer is set on the outer layer of the cable core to obtain a semi-finished power cable. A method for preparing carboxylated styrene-butadiene latex modified inorganic filler includes the following steps: Carboxylated styrene-butadiene latex (the amount of carboxylated styrene-butadiene latex added is 6% of the mass of carbon black) is added to 5 times its mass of water and dispersed evenly; carbon black is added and mixed at 40℃ for 1.5 h; after drying, carboxylated styrene-butadiene latex modified inorganic filler is obtained. A method for preparing hydroxyl acrylic emulsion modified inorganic filler includes the following steps: Hydroxy acrylic emulsion (the amount of hydroxyl acrylic emulsion added is 6% of the mass of carbon black) is added to 5 times its mass of water and dispersed evenly; carbon black is added and mixed at 40℃ for 1.5 h; after drying, hydroxyl acrylic emulsion modified inorganic filler is obtained. 100 parts of polyethylene (model: 4206), 20 parts of inorganic filler (composed of carboxylated styrene-butadiene latex modified inorganic filler and hydroxyl acrylic emulsion modified inorganic filler in a mass ratio of 1:2), 6 parts of magnesium hydroxide, and 8 parts of maleic anhydride-grafted polyethylene were mixed evenly to obtain a mixture. The mixture was then melt-extruded in a twin-screw extruder to coat the outside of the semi-finished power cable to form a sheath layer, thus obtaining an aging-resistant power cable. The operating parameters of the twin-screw extruder were: Zone 1 145℃, Zone 2 155℃, Zone 3 155℃, Zone 4 160℃, Zone 5 160℃, Zone 6 160℃, Zone 7 160℃, Zone 8 155℃, and the screw speed was 110 r / min.

[0036] Example 6 A method for preparing an aging-resistant power cable includes the following steps: Twenty copper wires are twisted together to obtain a conductor bundle; an insulation layer is wrapped around the outside of the conductor bundle to obtain an insulated core; four insulated cores are twisted together to obtain a cable core; the gaps between the insulated cores of the cable core are filled with polypropylene filler rope; a wrapping layer is set on the outer layer of the cable core to obtain a semi-finished power cable. A method for preparing carboxylated styrene-butadiene latex modified inorganic filler includes the following steps: Carboxylated styrene-butadiene latex (the amount of carboxylated styrene-butadiene latex added is 6% of the mass of carbon black) is added to 5 times its mass of water and dispersed evenly; carbon black is added and mixed at 40℃ for 1.5 h; after drying, carboxylated styrene-butadiene latex modified inorganic filler is obtained. A method for preparing hydroxyl acrylic emulsion modified inorganic filler includes the following steps: Hydroxy acrylic emulsion (the amount of hydroxyl acrylic emulsion added is 6% of the mass of carbon black) is added to 5 times its mass of water and dispersed evenly; carbon black is added and mixed at 40℃ for 1.5 h; after drying, hydroxyl acrylic emulsion modified inorganic filler is obtained. 100 parts of polyethylene (model: 608A), 15 parts of inorganic filler (composed of carboxylated styrene-butadiene latex modified inorganic filler and hydroxyl acrylic emulsion modified inorganic filler in a mass ratio of 2:1), 4 parts of magnesium hydroxide, and 6 parts of maleic anhydride-grafted polyethylene were mixed evenly to obtain a mixture. The mixture was then melt-extruded in a twin-screw extruder to coat the outside of the semi-finished power cable to form a sheath layer, thus obtaining an aging-resistant power cable. The operating parameters of the twin-screw extruder were: Zone 1 145℃, Zone 2 155℃, Zone 3 155℃, Zone 4 160℃, Zone 5 160℃, Zone 6 160℃, Zone 7 160℃, Zone 8 155℃, and the screw speed was 110 r / min.

[0037] Example 7 A method for preparing an aging-resistant power cable includes the following steps: Twenty copper wires are twisted together to obtain a conductor bundle; an insulation layer is wrapped around the outside of the conductor bundle to obtain an insulated core; four insulated cores are twisted together to obtain a cable core; the gaps between the insulated cores of the cable core are filled with polypropylene filler rope; a wrapping layer is set on the outer layer of the cable core to obtain a semi-finished power cable. A method for preparing carboxylated styrene-butadiene latex modified inorganic filler includes the following steps: Carboxylated styrene-butadiene latex (the amount of carboxylated styrene-butadiene latex added is 6% of the mass of carbon black) is added to 5 times its mass of water and dispersed evenly; carbon black is added and mixed at 40℃ for 1.5 h; after drying, carboxylated styrene-butadiene latex modified inorganic filler is obtained. A method for preparing hydroxyl acrylic emulsion modified inorganic filler includes the following steps: Hydroxy acrylic emulsion (the amount of hydroxyl acrylic emulsion added is 6% of the mass of carbon black) is added to 5 times its mass of water and dispersed evenly; carbon black is added and mixed at 40℃ for 1.5 h; after drying, hydroxyl acrylic emulsion modified inorganic filler is obtained. 100 parts of polyethylene (composed of polyethylene 608A and polyethylene 4206 in a mass ratio of 1:2), 15 parts of inorganic filler (composed of carboxylated styrene-butadiene latex modified inorganic filler and hydroxyl acrylic emulsion modified inorganic filler in a mass ratio of 2:1), 4 parts of magnesium hydroxide, and 6 parts of maleic anhydride-grafted polyethylene were mixed evenly to obtain a mixture. The mixture was then melt-extruded in a twin-screw extruder to coat the outside of the semi-finished power cable to form a sheath layer, resulting in an aging-resistant power cable. The operating parameters of the twin-screw extruder were: Zone 1 145℃, Zone 2 155℃, Zone 3 155℃, Zone 4 160℃, Zone 5 160℃, Zone 6 160℃, Zone 7 160℃, Zone 8 155℃, and the screw speed was 110 r / min.

[0038] Example 8 A method for preparing an aging-resistant power cable includes the following steps: Twenty copper wires are twisted together to obtain a conductor bundle; an insulation layer is wrapped around the outside of the conductor bundle to obtain an insulated core; four insulated cores are twisted together to obtain a cable core; the gaps between the insulated cores of the cable core are filled with polypropylene filler rope; a wrapping layer is set on the outer layer of the cable core to obtain a semi-finished power cable. A method for preparing carboxylated styrene-butadiene latex modified inorganic filler includes the following steps: Carboxylated styrene-butadiene latex (the amount of carboxylated styrene-butadiene latex added is 6% of the mass of carbon black) is added to 5 times its mass of water and dispersed evenly; carbon black is added and mixed at 40℃ for 1.5 h; after drying, carboxylated styrene-butadiene latex modified inorganic filler is obtained. A method for preparing hydroxyl acrylic emulsion modified inorganic filler includes the following steps: Hydroxy acrylic emulsion (the amount of hydroxyl acrylic emulsion added is 6% of the mass of carbon black) is added to 5 times its mass of water and dispersed evenly; carbon black is added and mixed at 40℃ for 1.5 h; after drying, hydroxyl acrylic emulsion modified inorganic filler is obtained. 100 parts of polyethylene (composed of polyethylene 608A and polyethylene 4206 in a mass ratio of 1:4), 15 parts of inorganic filler (composed of carboxylated styrene-butadiene latex modified inorganic filler and hydroxyl acrylic emulsion modified inorganic filler in a mass ratio of 2:1), 4 parts of magnesium hydroxide, and 6 parts of maleic anhydride-grafted polyethylene were mixed evenly to obtain a mixture. The mixture was then melt-extruded in a twin-screw extruder to coat the outside of the semi-finished power cable to form a sheath layer, resulting in an aging-resistant power cable. The operating parameters of the twin-screw extruder were: Zone 1 145℃, Zone 2 155℃, Zone 3 155℃, Zone 4 160℃, Zone 5 160℃, Zone 6 160℃, Zone 7 160℃, Zone 8 155℃, and the screw speed was 110 r / min.

[0039] Example 9 A method for preparing an aging-resistant power cable includes the following steps: Twenty copper wires are twisted together to obtain a conductor bundle; an insulation layer is wrapped around the outside of the conductor bundle to obtain an insulated core; four insulated cores are twisted together to obtain a cable core; the gaps between the insulated cores of the cable core are filled with polypropylene filler rope; a wrapping layer is set on the outer layer of the cable core to obtain a semi-finished power cable. A method for preparing carboxylated styrene-butadiene latex modified inorganic filler includes the following steps: Carboxylated styrene-butadiene latex (the amount of carboxylated styrene-butadiene latex added is 6% of the mass of carbon black) is added to 5 times its mass of water and dispersed evenly; carbon black is added and mixed at 40℃ for 1.5 h; after drying, carboxylated styrene-butadiene latex modified inorganic filler is obtained. A method for preparing hydroxyl acrylic emulsion modified inorganic filler includes the following steps: Hydroxy acrylic emulsion (the amount of hydroxyl acrylic emulsion added is 6% of the mass of carbon black) is added to 5 times its mass of water and dispersed evenly; carbon black is added and mixed at 40℃ for 1.5 h; after drying, hydroxyl acrylic emulsion modified inorganic filler is obtained. 100 parts of polyethylene (composed of polyethylene 608A and polyethylene 4206 in a 1:1 mass ratio), 15 parts of inorganic filler (composed of carboxylated styrene-butadiene latex modified inorganic filler and hydroxyl acrylic emulsion modified inorganic filler in a 2:1 mass ratio), 4 parts of magnesium hydroxide, and 6 parts of maleic anhydride-grafted polyethylene were mixed evenly to obtain a mixture. The mixture was then melt-extruded in a twin-screw extruder to coat the outside of the semi-finished power cable to form a sheath layer, resulting in an aging-resistant power cable. The operating parameters of the twin-screw extruder were: Zone 1 145℃, Zone 2 155℃, Zone 3 155℃, Zone 4 160℃, Zone 5 160℃, Zone 6 160℃, Zone 7 160℃, Zone 8 155℃, and the screw speed was 110 r / min.

[0040] Example 10 A method for preparing an aging-resistant power cable includes the following steps: Twenty copper wires are twisted together to obtain a conductor bundle; an insulation layer is wrapped around the outside of the conductor bundle to obtain an insulated core; four insulated cores are twisted together to obtain a cable core; the gaps between the insulated cores of the cable core are filled with polypropylene filler rope; a wrapping layer is set on the outer layer of the cable core to obtain a semi-finished power cable. A method for preparing carboxylated styrene-butadiene latex modified inorganic filler includes the following steps: Carboxylated styrene-butadiene latex (the amount of carboxylated styrene-butadiene latex added is 6% of the mass of carbon black) is added to 5 times its mass of water and dispersed evenly; carbon black is added and mixed at 40℃ for 1.5 h; after drying, carboxylated styrene-butadiene latex modified inorganic filler is obtained. A method for preparing hydroxyl acrylic emulsion modified inorganic filler includes the following steps: Hydroxy acrylic emulsion (the amount of hydroxyl acrylic emulsion added is 6% of the mass of carbon black) is added to 5 times its mass of water and dispersed evenly; carbon black is added and mixed at 40℃ for 1.5 h; after drying, hydroxyl acrylic emulsion modified inorganic filler is obtained. 100 parts of polyethylene (composed of polyethylene 608A and polyethylene 4206 in a mass ratio of 1:5), 15 parts of inorganic filler (composed of carboxylated styrene-butadiene latex modified inorganic filler and hydroxyl acrylic emulsion modified inorganic filler in a mass ratio of 2:1), 4 parts of magnesium hydroxide, and 6 parts of maleic anhydride-grafted polyethylene were mixed evenly to obtain a mixture. The mixture was then melt-extruded in a twin-screw extruder to coat the outside of the semi-finished power cable to form a sheath layer, resulting in an aging-resistant power cable. The operating parameters of the twin-screw extruder were: Zone 1 145℃, Zone 2 155℃, Zone 3 155℃, Zone 4 160℃, Zone 5 160℃, Zone 6 160℃, Zone 7 160℃, Zone 8 155℃, and the screw speed was 110 r / min.

[0041] Comparative Example 1 Twenty copper wires are twisted together to obtain a conductor bundle; an insulation layer is wrapped around the outside of the conductor bundle to obtain an insulated core; four insulated cores are twisted together to obtain a cable core; the gaps between the insulated cores of the cable core are filled with polypropylene filler rope; a wrapping layer is set on the outer layer of the cable core to obtain a semi-finished power cable. The preparation method of carboxylated styrene-butadiene latex modified inorganic filler includes the following steps: carboxylated styrene-butadiene latex (the amount of carboxylated styrene-butadiene latex added is 6% of the mass of carbon black) is added to 5 times the mass of water and dispersed evenly, then carbon black is added and mixed at 40℃ for 1.5h, and then dried to obtain carboxylated styrene-butadiene latex modified inorganic filler. 100 parts of polyethylene (model: 4206), 15 parts of carboxylated styrene-butadiene latex modified inorganic filler, 4 parts of magnesium hydroxide, and 6 parts of maleic anhydride grafted polyethylene were mixed evenly to obtain a mixture. The mixture was then melt-extruded in a twin-screw extruder to coat the outside of the semi-finished power cable to form a sheath layer, thus obtaining an aging-resistant power cable. The operating parameters of the twin-screw extruder were: Zone 1 145℃, Zone 2 155℃, Zone 3 155℃, Zone 4 160℃, Zone 5 160℃, Zone 6 160℃, Zone 7 160℃, Zone 8 155℃, and the screw speed was 110 r / min.

[0042] Comparative Example 2 Twenty copper wires are twisted together to obtain a conductor bundle; an insulation layer is wrapped around the outside of the conductor bundle to obtain an insulated core; four insulated cores are twisted together to obtain a cable core; the gaps between the insulated cores of the cable core are filled with polypropylene filler rope; a wrapping layer is set on the outer layer of the cable core to obtain a semi-finished power cable. The preparation method of hydroxy acrylic emulsion modified inorganic filler includes the following steps: adding hydroxy acrylic emulsion (the amount of hydroxy acrylic emulsion added is 6% of the mass of carbon black) to 5 times the mass of water and dispersing it evenly, then adding carbon black and mixing at 40℃ for 1.5h, and then drying to obtain hydroxy acrylic emulsion modified inorganic filler. 100 parts of polyethylene (model: 4206), 15 parts of hydroxyl acrylic emulsion modified inorganic filler, 4 parts of magnesium hydroxide, and 6 parts of maleic anhydride grafted polyethylene were mixed evenly to obtain a mixture. The mixture was then melt-extruded in a twin-screw extruder to coat the outside of the semi-finished power cable to form a sheath layer, thus obtaining an aging-resistant power cable. The operating parameters of the twin-screw extruder were: Zone 1 145℃, Zone 2 155℃, Zone 3 155℃, Zone 4 160℃, Zone 5 160℃, Zone 6 160℃, Zone 7 160℃, Zone 8 155℃, and the screw speed was 110 r / min.

[0043] Comparative Example 3 Twenty copper wires are twisted together to obtain a conductor bundle; an insulation layer is wrapped around the outside of the conductor bundle to obtain an insulated core; four insulated cores are twisted together to obtain a cable core; the gaps between the insulated cores of the cable core are filled with polypropylene filler rope; a wrapping layer is set on the outer layer of the cable core to obtain a semi-finished power cable. 100 parts of polyethylene (model: 4206), 15 parts of carbon black, 4 parts of magnesium hydroxide, and 6 parts of maleic anhydride-grafted polyethylene are mixed evenly to obtain a mixture. The mixture is then melt-extruded in a twin-screw extruder to coat the outside of the semi-finished power cable to form a sheath layer, resulting in an aging-resistant power cable. The operating parameters of the twin-screw extruder are: Zone 1 145℃, Zone 2 155℃, Zone 3 155℃, Zone 4 160℃, Zone 5 160℃, Zone 6 160℃, Zone 7 160℃, Zone 8 155℃, and the screw speed is 110 r / min.

[0044] Performance testing The tensile strength was tested according to the test method specified in GB / T 1040.1-2018 "Determination of tensile properties of plastics - Part 1: General rules"; the test speed was 200 mm / min. Following the fluorescent ultraviolet aging treatment according to GB / T 16422.3-2022 "Laboratory Light Source Exposure Test Methods for Plastics Part 3: Fluorescent Ultraviolet Lamps", the tensile strength after the fluorescent ultraviolet aging treatment was determined. The fluorescent ultraviolet aging test method was Method A: Cycle 1 of artificial accelerated climate aging using a UVA-340 lamp, with a test time of 720 hours (60 cycles).

[0045] The performance of the power cable sheath in each embodiment and comparative example was tested and is shown in Tables 1 and 2.

[0046] Table 1. Results of sheath performance tests in Examples 1-5 and Comparative Examples 1-3

[0047] In Table 1, the tensile strength and aging resistance of the sheath layer in Examples 1-5 are higher than those in Comparative Examples 1-3. Therefore, the inorganic filler composed of carboxylated styrene-butadiene latex modified inorganic filler and hydroxyl acrylic emulsion modified inorganic filler in this invention can improve the tensile strength and aging resistance of the sheath layer.

[0048] Table 2 Results of sheath layer performance testing in Examples 6-10

[0049] In Table 2, the tensile strength of the sheath layer in Examples 7-8 is higher than that in Examples 6 and 9-10. Therefore, the addition of composite polyethylene composed of polyethylene with a melt index of 2.6 g / 10 min and polyethylene with a melt index of 5 g / 10 min in this invention can synergistically improve the tensile strength of the sheath layer.

[0050] 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. An aging-resistant power cable, characterized in that, From the inside out, it includes a cable core and a sheath layer. The cable core is made of multiple strands of insulated wire cores twisted together. The insulated wire core includes a conductor bundle and an insulating layer covering the outside of the conductor bundle. The sheath layer includes the following raw materials: polyethylene, inorganic filler, flame retardant, and compatibilizer.

2. The aging-resistant power cable according to claim 1, characterized in that, The conductor bundle is made of 18 to 20 strands of metal wire twisted together.

3. The aging-resistant power cable according to claim 1, characterized in that, The insulation layer is a cross-linked polyethylene insulation layer.

4. The aging-resistant power cable according to claim 1, characterized in that, The gaps between the insulated wires of the cable core are filled with a filler material.

5. The aging-resistant power cable according to claim 1, characterized in that, A wrapping layer is provided between the cable core and the sheath layer.

6. The aging-resistant power cable according to claim 1, characterized in that, The sheath layer comprises the following raw materials in parts by weight: 100 parts polyethylene, 15-20 parts inorganic filler, 4-6 parts flame retardant, and 6-8 parts compatibilizer; The inorganic filler is composed of carboxylated styrene-butadiene latex modified inorganic filler and hydroxyl acrylic emulsion modified inorganic filler in a mass ratio of 2:1~3.

7. The aging-resistant power cable according to claim 6, characterized in that, The preparation method of the carboxylated styrene-butadiene latex modified inorganic filler includes the following steps: after adding carboxylated styrene-butadiene latex into a solvent and dispersing it evenly, adding inorganic filler A and mixing, and then drying to obtain carboxylated styrene-butadiene latex modified inorganic filler; The preparation method of the hydroxy acrylic emulsion modified inorganic filler includes the following steps: after the hydroxy acrylic emulsion is added to a solvent and dispersed evenly, inorganic filler B is added and mixed, and then dried to obtain the hydroxy acrylic emulsion modified inorganic filler.

8. The aging-resistant power cable according to claim 1, characterized in that, The polyethylene has a melt index of 2~10 g / 10 min, and the test conditions are 190℃ and 2.16 kg load.

9. The aging-resistant power cable according to claim 8, characterized in that, The polyethylene is a composite polyethylene, which is composed of polyethylene with a melt index of 2 to 2.6 g / 10 min and polyethylene with a melt index of 5 to 10 g / 10 min in a mass ratio of 1:2 to 4. The melt index test conditions are 190°C and 2.16 kg load.

10. The aging-resistant power cable according to claim 1, characterized in that, The inorganic filler includes one or more of montmorillonite, carbon black, and titanium dioxide.

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