Aging-resistant overhead insulated cable

Abstract

The application relates to the technical field of cables, and discloses an anti-aging overhead insulated cable, which comprises, from inside to outside, a conductor, a shielding layer, an insulation layer and a sheath layer; the conductor is formed by twisting a plurality of wires; the raw material of the sheath layer comprises the following components in parts by weight: butadiene styrene rubber 70-80 parts, butyronitrile rubber 20-30 parts, polycarbonate 15-20 parts, filler 30-40 parts, anti-aging agent 2-4 parts, aromatic oil 3-5 parts, vulcanizing agent 1-3 parts, activator 3-5 parts and accelerator 2-4 parts. The above technical scheme solves the problem of insufficient anti-aging property of the sheath layer in the related art.

Description

Technical Field

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

[0002] Overhead insulated cables have advantages such as small laying spacing, high safety and reliability, and less susceptibility to external environmental influences. They are widely used in urban and rural power grid transformation, forest areas, mining areas, and densely built-up areas. The reliability, stability, and durability of their performance are directly related to the safe operation of the entire system. Therefore, higher requirements are placed on the performance of overhead insulated cables.

[0003] During use, overhead insulation inevitably experiences thermal effects. These thermal effects accelerate the thermal movement of the molecular chains in the sheath material of overhead insulated cables, leading to molecular chain breakage and subsequent embrittlement, cracking, and pulverization of the sheath. Therefore, developing an aging-resistant overhead insulated cable is of great significance. Summary of the Invention

[0004] This invention proposes an aging-resistant overhead insulated cable, which solves the problem of insufficient aging resistance of the sheath layer in related technologies.

[0005] The technical solution of the present invention is as follows: This invention proposes an aging-resistant overhead insulated cable, comprising, from the inside out, a conductor, a shielding layer, an insulation layer, and a sheath layer; the conductor is composed of multiple stranded wires; the raw materials of the sheath layer include the following components by weight: 70-80 parts styrene-butadiene rubber, 20-30 parts nitrile rubber, 15-20 parts polycarbonate, 30-40 parts filler, 2-4 parts antioxidant, 3-5 parts aromatic oil, 1-3 parts vulcanizing agent, 3-5 parts activator, and 2-4 parts accelerator.

[0006] As a further technical solution, the conductor includes an aluminum alloy conductor or a copper alloy conductor.

[0007] As a further technical solution, the shielding layer is a metal shielding layer.

[0008] As a further technical solution, the insulation layer is a cross-linked polyethylene insulation layer.

[0009] As a further technical solution, the filler is calcium silicate composite zirconium dioxide.

[0010] As a further technical solution, the preparation method of the calcium silicate composite zirconium dioxide includes the following steps: A1. After dispersing calcium silicate evenly in a solvent, add a surfactant and mix to obtain premixed solution I; A2. After adding zirconium oxychloride octahydrate to the premixed solution I and mixing, premixed solution II is obtained; A3. After adjusting the pH of the premixed solution II to 10-11, continue mixing, and then aging, filtering, and drying to obtain the calcium silicate composite zirconium dioxide.

[0011] This invention improves the aging resistance of the sheath layer of overhead insulated cables by adding calcium silicate composite zirconium dioxide as a filler. The reason is that calcium silicate itself has excellent heat aging resistance, but it is prone to agglomeration, which makes it difficult to fully exert its heat aging resistance performance and thus cannot effectively improve the aging resistance of the sheath layer. After the composite treatment of zirconium dioxide and calcium silicate, physical isolation between calcium silicate can be achieved, thereby effectively preventing secondary agglomeration of calcium silicate. At the same time, zirconium dioxide also has excellent thermal stability, which works synergistically with calcium silicate to further improve the aging resistance of the sheath layer of overhead insulated cables.

[0012] As a further technical solution, the mass ratio of calcium silicate to zirconium oxychloride octahydrate is 7:3~4, for example, it can be 7:3, 7:3.5, or 7:4, preferably 7:3.5.

[0013] As a further technical solution, in step A1, the mixing temperature is 35~45℃ and the mixing time is 1.5~2.5h.

[0014] As a further technical solution, in step A1, the solvent is water.

[0015] As a further technical solution, in step A2, the mixing temperature is 35~45℃ and the mixing time is 1~2h.

[0016] As a further technical solution, the mass ratio of calcium silicate to surfactant is 100:5~7.

[0017] As a further technical solution, in step A3, the aging time is 1~2 hours.

[0018] As a further technical solution, the polycarbonate is composed of a first polycarbonate and a second polycarbonate, wherein the first polycarbonate and the second polycarbonate have different melt indices.

[0019] As a further technical solution, the melt index of the first polycarbonate is 9 cm⁻¹. 3 / 10min; the melt index of the second polycarbonate is 34cm. 3 / 10min; the test conditions for the melt index of the first and second polycarbonates were both 300℃ / 1.2kg.

[0020] This invention improves the mechanical properties of the sheath layer of overhead insulated cables by using polycarbonates with different melt indices. The first polycarbonate with a lower melt index provides good structural stability and molding density for the sheath layer, reducing problems such as internal porosity and defects caused by excessively fast melt flow during processing. The second polycarbonate with a higher melt index improves the overall processing fluidity of the sheath layer raw material system, improves the dispersion uniformity of raw materials during mixing and extrusion molding, and avoids problems such as uneven component dispersion and poor interfacial bonding caused by insufficient system fluidity. Thus, the mechanical properties of the sheath layer of overhead insulated cables are synergistically improved.

[0021] As a further technical solution, the mass ratio of the first polycarbonate and the second polycarbonate is 7:5 to 6, for example, it can be 7:5, 7:5.5, or 7:6, preferably 7:5.5.

[0022] As a further technical solution, the antioxidant includes one or more of antioxidant 4010NA, antioxidant RD, and antioxidant 2246.

[0023] As a further technical solution, the vulcanizing agent is sulfur.

[0024] As a further technical solution, the activator includes zinc oxide and stearic acid.

[0025] As a further technical solution, the accelerator includes one or more of accelerator M, accelerator CZ, and accelerator DM.

[0026] The working principle and beneficial effects of this invention are as follows: This invention improves the aging resistance of the sheath layer of overhead insulated cables by using a combination of styrene-butadiene rubber (SBR), nitrile rubber (NBR), and polycarbonate. SBR serves as the main base material, providing the sheath layer with basic aging resistance. Polycarbonate, with its high heat distortion temperature, acts as a heat-resistant reinforcing phase. The polarity of NBR acts as a compatibilizer, improving the dispersion of polycarbonate within SBR. The synergistic effect of these three materials effectively inhibits chain breakage and phase separation caused by heat aging, thereby enhancing the aging resistance of the overhead insulated cable sheath layer. Detailed Implementation

[0027] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0028] In the following examples and comparative examples: The melt index of the first polycarbonate is 9 cm⁻¹. 3 / 10min, test conditions: 300℃ / 1.2kg, model: 2805; the melt index of the second polycarbonate is 34cm. 3 / 10min, test conditions are 300℃ / 1.2kg, model: M204LF; styrene-butadiene rubber, model: 1502; acrylonitrile rubber, model: 3305E; aromatic oil, model: s-1000; sulfur, model: S-80; calcium silicate, average particle size: 100nm.

[0029] Example 1 An aging-resistant overhead insulated cable comprises, from the inside out, a conductor, a shielding layer, an insulation layer, and a sheath layer; the raw materials of the sheath layer include the following components by weight: 70 parts styrene-butadiene rubber, 20 parts nitrile rubber, 15 parts polycarbonate, 30 parts calcium silicate composite zirconium dioxide, 2 parts antioxidant RD, 3 parts aromatic oil, 1 part sulfur, 2 parts zinc oxide, 1 part stearic acid, and 2 parts accelerator DM, wherein the polycarbonate is the first polycarbonate; The preparation method of calcium silicate composite zirconium dioxide includes the following steps: A1. After dispersing calcium silicate evenly in water (the mass-volume ratio of calcium silicate to water is 1g:10mL), add Tween 80 and mix at 35℃ for 2.5h to obtain premixed solution I, wherein the mass ratio of calcium silicate to Tween 80 is 100:5. A2. Add zirconium oxychloride octahydrate to premix solution I and mix at 35°C for 2 hours to obtain premix solution II; A3. Add 25% ammonia water to premixed solution II to adjust the pH value to 10, continue mixing for 1 hour, then age for 1 hour, filter and dry to obtain calcium silicate composite zirconium dioxide, wherein the mass ratio of calcium silicate to zirconium oxychloride octahydrate is 7:3. A method for preparing an aging-resistant overhead insulated cable includes the following steps: S1. The shielding material is wrapped around the outside of a conductor made of 7 stranded aluminum alloy wires to form a shielding layer; S2. Extrude the insulating material onto the outside of the shielding layer to form an insulating layer; S3. After the raw materials of the sheath layer are mixed evenly, they are extruded and wrapped on the outside of the insulation layer, vulcanized, and a sheath layer is formed to obtain an aging-resistant overhead insulated cable.

[0030] Example 2 An aging-resistant overhead insulated cable comprises, from the inside out, a conductor, a shielding layer, an insulation layer, and a sheath layer; the raw materials of the sheath layer include the following components by weight: 75 parts styrene-butadiene rubber, 25 parts nitrile rubber, 17 parts polycarbonate, 35 parts calcium silicate composite zirconium dioxide, 3 parts antioxidant RD, 4 parts aromatic oil, 2 parts sulfur, 3 parts zinc oxide, 1 part stearic acid, and 3 parts accelerator DM, wherein the polycarbonate is the first polycarbonate; The preparation method of calcium silicate composite zirconium dioxide includes the following steps: A1. After dispersing calcium silicate evenly in water (the mass-volume ratio of calcium silicate to water is 1g:10mL), add Tween 80 and mix at 40℃ for 2h to obtain premixed solution I, wherein the mass ratio of calcium silicate to Tween 80 is 100:6. A2. Add zirconium oxychloride octahydrate to premix solution I and mix at 40°C for 1.5 h to obtain premix solution II; A3. Add 25% ammonia water to premixed solution II to adjust the pH value to 11, continue mixing for 1.5 hours, then age for 1.5 hours, filter and dry to obtain calcium silicate composite zirconium dioxide, wherein the mass ratio of calcium silicate to zirconium oxychloride octahydrate is 7:3. A method for preparing an aging-resistant overhead insulated cable includes the following steps: S1. The shielding material is wrapped around the outside of a conductor made of 7 stranded aluminum alloy wires to form a shielding layer; S2. Extrude the insulating material onto the outside of the shielding layer to form an insulating layer; S3. After the raw materials of the sheath layer are mixed evenly, they are extruded and wrapped on the outside of the insulation layer, vulcanized, and a sheath layer is formed to obtain an aging-resistant overhead insulated cable.

[0031] Example 3 An aging-resistant overhead insulated cable comprises, from the inside out, a conductor, a shielding layer, an insulation layer, and a sheath layer; the raw materials of the sheath layer include the following components by weight: 80 parts styrene-butadiene rubber, 30 parts nitrile rubber, 20 parts polycarbonate, 40 parts calcium silicate composite zirconium dioxide, 4 parts antioxidant RD, 5 parts aromatic oil, 3 parts sulfur, 3 parts zinc oxide, 2 parts stearic acid, and 4 parts accelerator DM, wherein the polycarbonate is the first polycarbonate; The preparation method of calcium silicate composite zirconium dioxide includes the following steps: A1. After dispersing calcium silicate evenly in water (the mass-volume ratio of calcium silicate to water is 1g:10mL), add Tween 80 and mix at 45℃ for 1.5h to obtain premixed solution I, wherein the mass ratio of calcium silicate to Tween 80 is 100:7. A2. Add zirconium oxychloride octahydrate to premix solution I and mix at 45°C for 1 hour to obtain premix solution II; A3. Add 25% ammonia water to premixed solution II to adjust the pH value to 11, continue mixing for 2 hours, then age for 2 hours, filter and dry to obtain calcium silicate composite zirconium dioxide, wherein the mass ratio of calcium silicate to zirconium oxychloride octahydrate is 7:3. A method for preparing an aging-resistant overhead insulated cable includes the following steps: S1. The shielding material is wrapped around the outside of a conductor made of 7 stranded aluminum alloy wires to form a shielding layer; S2. Extrude the insulating material onto the outside of the shielding layer to form an insulating layer; S3. After the raw materials of the sheath layer are mixed evenly, they are extruded and wrapped on the outside of the insulation layer, vulcanized, and a sheath layer is formed to obtain an aging-resistant overhead insulated cable.

[0032] Example 4 An aging-resistant overhead insulated cable comprises, from the inside out, a conductor, a shielding layer, an insulation layer, and a sheath layer; the raw materials of the sheath layer include the following components by weight: 75 parts styrene-butadiene rubber, 25 parts nitrile rubber, 17 parts polycarbonate, 35 parts calcium silicate composite zirconium dioxide, 3 parts antioxidant RD, 4 parts aromatic oil, 2 parts sulfur, 3 parts zinc oxide, 1 part stearic acid, and 3 parts accelerator DM, wherein the polycarbonate is the first polycarbonate; The preparation method of calcium silicate composite zirconium dioxide includes the following steps: A1. After dispersing calcium silicate evenly in water (the mass-volume ratio of calcium silicate to water is 1g:10mL), add Tween 80 and mix at 40℃ for 2h to obtain premixed solution I, wherein the mass ratio of calcium silicate to Tween 80 is 100:6. A2. Add zirconium oxychloride octahydrate to premix solution I and mix at 40°C for 1.5 h to obtain premix solution II; A3. Add 25% ammonia water to premixed solution II to adjust the pH value to 11, continue mixing for 1.5 hours, then age for 1.5 hours, filter and dry to obtain calcium silicate composite zirconium dioxide, wherein the mass ratio of calcium silicate to zirconium oxychloride octahydrate is 7:3.5. A method for preparing an aging-resistant overhead insulated cable includes the following steps: S1. The shielding material is wrapped around the outside of a conductor made of 7 stranded aluminum alloy wires to form a shielding layer; S2. Extrude the insulating material onto the outside of the shielding layer to form an insulating layer; S3. After the raw materials of the sheath layer are mixed evenly, they are extruded and wrapped on the outside of the insulation layer, vulcanized, and a sheath layer is formed to obtain an aging-resistant overhead insulated cable.

[0033] Example 5 An aging-resistant overhead insulated cable comprises, from the inside out, a conductor, a shielding layer, an insulation layer, and a sheath layer; the raw materials of the sheath layer include the following components by weight: 75 parts styrene-butadiene rubber, 25 parts nitrile rubber, 17 parts polycarbonate, 35 parts calcium silicate composite zirconium dioxide, 3 parts antioxidant RD, 4 parts aromatic oil, 2 parts sulfur, 3 parts zinc oxide, 1 part stearic acid, and 3 parts accelerator DM, wherein the polycarbonate is the first polycarbonate; The preparation method of calcium silicate composite zirconium dioxide includes the following steps: A1. After dispersing calcium silicate evenly in water (the mass-volume ratio of calcium silicate to water is 1g:10mL), add Tween 80 and mix at 40℃ for 2h to obtain premixed solution I, wherein the mass ratio of calcium silicate to Tween 80 is 100:6. A2. Add zirconium oxychloride octahydrate to premix solution I and mix at 40°C for 1.5 h to obtain premix solution II; A3. Add 25% ammonia water to premixed solution II to adjust the pH value to 11, continue mixing for 1.5 hours, then age for 1.5 hours, filter and dry to obtain calcium silicate composite zirconium dioxide, wherein the mass ratio of calcium silicate to zirconium oxychloride octahydrate is 7:4. A method for preparing an aging-resistant overhead insulated cable includes the following steps: S1. The shielding material is wrapped around the outside of a conductor made of 7 stranded aluminum alloy wires to form a shielding layer; S2. Extrude the insulating material onto the outside of the shielding layer to form an insulating layer; S3. After the raw materials of the sheath layer are mixed evenly, they are extruded and wrapped on the outside of the insulation layer, vulcanized, and a sheath layer is formed to obtain an aging-resistant overhead insulated cable.

[0034] Example 6 An aging-resistant overhead insulated cable comprises, from the inside out, a conductor, a shielding layer, an insulation layer, and a sheath layer; the raw materials of the sheath layer include the following components by weight: 75 parts styrene-butadiene rubber, 25 parts nitrile rubber, 17 parts polycarbonate, 35 parts calcium silicate composite zirconium dioxide, 3 parts antioxidant RD, 4 parts aromatic oil, 2 parts sulfur, 3 parts zinc oxide, 1 part stearic acid, and 3 parts accelerator DM, wherein the polycarbonate is a second type of polycarbonate; The preparation method of calcium silicate composite zirconium dioxide includes the following steps: A1. After dispersing calcium silicate evenly in water (the mass-volume ratio of calcium silicate to water is 1g:10mL), add Tween 80 and mix at 40℃ for 2h to obtain premixed solution I, wherein the mass ratio of calcium silicate to Tween 80 is 100:6. A2. Add zirconium oxychloride octahydrate to premix solution I and mix at 40°C for 1.5 h to obtain premix solution II; A3. Add 25% ammonia water to premixed solution II to adjust the pH value to 11, continue mixing for 1.5 hours, then age for 1.5 hours, filter and dry to obtain calcium silicate composite zirconium dioxide, wherein the mass ratio of calcium silicate to zirconium oxychloride octahydrate is 7:3. A method for preparing an aging-resistant overhead insulated cable includes the following steps: S1. The shielding material is wrapped around the outside of a conductor made of 7 stranded aluminum alloy wires to form a shielding layer; S2. Extrude the insulating material onto the outside of the shielding layer to form an insulating layer; S3. After the raw materials of the sheath layer are mixed evenly, they are extruded and wrapped on the outside of the insulation layer, vulcanized, and a sheath layer is formed to obtain an aging-resistant overhead insulated cable.

[0035] Example 7 An aging-resistant overhead insulated cable comprises, from the inside out, a conductor, a shielding layer, an insulation layer, and a sheath layer. The raw materials of the sheath layer include the following components by weight: 75 parts styrene-butadiene rubber, 25 parts nitrile rubber, 17 parts polycarbonate, 35 parts calcium silicate composite zirconium dioxide, 3 parts antioxidant RD, 4 parts aromatic oil, 2 parts sulfur, 3 parts zinc oxide, 1 part stearic acid, and 3 parts accelerator DM. The polycarbonate is composed of a first polycarbonate and a second polycarbonate in a mass ratio of 7:5. The preparation method of calcium silicate composite zirconium dioxide includes the following steps: A1. After dispersing calcium silicate evenly in water (the mass-volume ratio of calcium silicate to water is 1g:10mL), add Tween 80 and mix at 40℃ for 2h to obtain premixed solution I, wherein the mass ratio of calcium silicate to Tween 80 is 100:6. A2. Add zirconium oxychloride octahydrate to premix solution I and mix at 40°C for 1.5 h to obtain premix solution II; A3. Add 25% ammonia water to premixed solution II to adjust the pH value to 11, continue mixing for 1.5 hours, then age for 1.5 hours, filter and dry to obtain calcium silicate composite zirconium dioxide, wherein the mass ratio of calcium silicate to zirconium oxychloride octahydrate is 7:3. A method for preparing an aging-resistant overhead insulated cable includes the following steps: S1. The shielding material is wrapped around the outside of a conductor made of 7 stranded aluminum alloy wires to form a shielding layer; S2. Extrude the insulating material onto the outside of the shielding layer to form an insulating layer; S3. After the raw materials of the sheath layer are mixed evenly, they are extruded and wrapped on the outside of the insulation layer, vulcanized, and a sheath layer is formed to obtain an aging-resistant overhead insulated cable.

[0036] Example 8 An aging-resistant overhead insulated cable comprises, from the inside out, a conductor, a shielding layer, an insulation layer, and a sheath layer. The raw materials of the sheath layer include the following components by weight: 75 parts styrene-butadiene rubber, 25 parts nitrile rubber, 17 parts polycarbonate, 35 parts calcium silicate composite zirconium dioxide, 3 parts antioxidant RD, 4 parts aromatic oil, 2 parts sulfur, 3 parts zinc oxide, 1 part stearic acid, and 3 parts accelerator DM. The polycarbonate is composed of a first polycarbonate and a second polycarbonate in a mass ratio of 7:5.5. The preparation method of calcium silicate composite zirconium dioxide includes the following steps: A1. After dispersing calcium silicate evenly in water (the mass-volume ratio of calcium silicate to water is 1g:10mL), add Tween 80 and mix at 40℃ for 2h to obtain premixed solution I, wherein the mass ratio of calcium silicate to Tween 80 is 100:6. A2. Add zirconium oxychloride octahydrate to premix solution I and mix at 40°C for 1.5 h to obtain premix solution II; A3. Add 25% ammonia water to premixed solution II to adjust the pH value to 11, continue mixing for 1.5 hours, then age for 1.5 hours, filter and dry to obtain calcium silicate composite zirconium dioxide, wherein the mass ratio of calcium silicate to zirconium oxychloride octahydrate is 7:3. A method for preparing an aging-resistant overhead insulated cable includes the following steps: S1. The shielding material is wrapped around the outside of a conductor made of 7 stranded aluminum alloy wires to form a shielding layer; S2. Extrude the insulating material onto the outside of the shielding layer to form an insulating layer; S3. After the raw materials of the sheath layer are mixed evenly, they are extruded and wrapped on the outside of the insulation layer, vulcanized, and a sheath layer is formed to obtain an aging-resistant overhead insulated cable.

[0037] Example 9 An aging-resistant overhead insulated cable comprises, from the inside out, a conductor, a shielding layer, an insulation layer, and a sheath layer. The raw materials of the sheath layer include the following components by weight: 75 parts styrene-butadiene rubber, 25 parts nitrile rubber, 17 parts polycarbonate, 35 parts calcium silicate composite zirconium dioxide, 3 parts antioxidant RD, 4 parts aromatic oil, 2 parts sulfur, 3 parts zinc oxide, 1 part stearic acid, and 3 parts accelerator DM. The polycarbonate is composed of a first polycarbonate and a second polycarbonate in a mass ratio of 7:6. The preparation method of calcium silicate composite zirconium dioxide includes the following steps: A1. After dispersing calcium silicate evenly in water (the mass-volume ratio of calcium silicate to water is 1g:10mL), add Tween 80 and mix at 40℃ for 2h to obtain premixed solution I, wherein the mass ratio of calcium silicate to Tween 80 is 100:6. A2. Add zirconium oxychloride octahydrate to premix solution I and mix at 40°C for 1.5 h to obtain premix solution II; A3. Add 25% ammonia water to premixed solution II to adjust the pH value to 11, continue mixing for 1.5 hours, then age for 1.5 hours, filter and dry to obtain calcium silicate composite zirconium dioxide, wherein the mass ratio of calcium silicate to zirconium oxychloride octahydrate is 7:3. A method for preparing an aging-resistant overhead insulated cable includes the following steps: S1. The shielding material is wrapped around the outside of a conductor made of 7 stranded aluminum alloy wires to form a shielding layer; S2. Extrude the insulating material onto the outside of the shielding layer to form an insulating layer; S3. After the raw materials of the sheath layer are mixed evenly, they are extruded and wrapped on the outside of the insulation layer, vulcanized, and a sheath layer is formed to obtain an aging-resistant overhead insulated cable.

[0038] Example 10 An aging-resistant overhead insulated cable comprises, from the inside out, a conductor, a shielding layer, an insulation layer, and a sheath layer; the raw materials of the sheath layer include the following components by weight: 75 parts styrene-butadiene rubber, 25 parts nitrile rubber, 17 parts polycarbonate, 35 parts calcium silicate, 3 parts antioxidant RD, 4 parts aromatic oil, 2 parts sulfur, 3 parts zinc oxide, 1 part stearic acid, and 3 parts accelerator DM, wherein the polycarbonate is the first polycarbonate; A method for preparing an aging-resistant overhead insulated cable includes the following steps: S1. The shielding material is wrapped around the outside of a conductor made of 7 stranded aluminum alloy wires to form a shielding layer; S2. Extrude the insulating material onto the outside of the shielding layer to form an insulating layer; S3. After the raw materials of the sheath layer are mixed evenly, they are extruded and wrapped on the outside of the insulation layer, vulcanized, and a sheath layer is formed to obtain an aging-resistant overhead insulated cable.

[0039] Comparative Example 1 An aging-resistant overhead insulated cable comprises, from the inside out, a conductor, a shielding layer, an insulation layer, and a sheath layer; the raw materials of the sheath layer include the following components by weight: 75 parts styrene-butadiene rubber, 25 parts nitrile rubber, 35 parts calcium silicate composite zirconium dioxide, 3 parts antioxidant RD, 4 parts aromatic oil, 2 parts sulfur, 3 parts zinc oxide, 1 part stearic acid, and 3 parts accelerator DM. The preparation method of calcium silicate composite zirconium dioxide includes the following steps: A1. After dispersing calcium silicate evenly in water (the mass-volume ratio of calcium silicate to water is 1g:10mL), add Tween 80 and mix at 40℃ for 2h to obtain premixed solution I, wherein the mass ratio of calcium silicate to Tween 80 is 100:6. A2. Add zirconium oxychloride octahydrate to premix solution I and mix at 40°C for 1.5 h to obtain premix solution II; A3. Add 25% ammonia water to premixed solution II to adjust the pH value to 11, continue mixing for 1.5 hours, then age for 1.5 hours, filter and dry to obtain calcium silicate composite zirconium dioxide, wherein the mass ratio of calcium silicate to zirconium oxychloride octahydrate is 7:3. A method for preparing an aging-resistant overhead insulated cable includes the following steps: S1. The shielding material is wrapped around the outside of a conductor made of 7 stranded aluminum alloy wires to form a shielding layer; S2. Extrude the insulating material onto the outside of the shielding layer to form an insulating layer; S3. After the raw materials of the sheath layer are mixed evenly, they are extruded and wrapped on the outside of the insulation layer, vulcanized, and a sheath layer is formed to obtain an aging-resistant overhead insulated cable.

[0040] Test case The sheath layers of the aging-resistant overhead insulated cables prepared in Examples 1-10 and Comparative Example 1 were tested according to the following method: 1. Tensile strength: The tensile strength of the specimen shall be tested in accordance with the method specified in GB / T 528-2009 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber", wherein the specimen shall be a type 1 dumbbell-shaped specimen and the test speed shall be 500 mm / min. 2. Aging resistance: The aging resistance test was conducted according to the method specified in GB / T 3512-2014 "Accelerated aging and heat resistance test of vulcanized rubber or thermoplastic rubber in hot air". During the aging resistance test, a cabinet-type hot air aging chamber as described in Method A was used, with 5 air changes per hour, a temperature of 200℃, and a time of 72 hours. After the heat aging test, the tensile strength of the specimen was tested according to the method specified in GB / T 528-2009 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber". The specimen was a type 1 dumbbell-shaped specimen, and the test speed was 500 mm / min. The change rate of tensile strength under aging resistance (%) = (tensile strength before aging resistance test - tensile strength after aging resistance test) / tensile strength before aging resistance test × 100%.

[0041] The test results are shown in Tables 1 and 2 below.

[0042] Table 1 Performance test results of overhead insulated cable sheaths in Examples 1-5, Example 10, and Comparative Example 1

[0043] As shown in Table 1, the change rate of tensile strength under aging in Examples 1-5 is lower than that in Example 10, indicating that the present invention improves the aging resistance of the overhead insulated cable sheath by adding calcium silicate composite zirconium dioxide as a filler; the change rate of tensile strength under aging in Examples 1-5 is lower than that in Comparative Example 1, indicating that the present invention improves the aging resistance of the overhead insulated cable sheath by adding polycarbonate.

[0044] Table 2 Performance test results of overhead insulated cable sheaths in Examples 2 and 6-9

[0045] As can be seen from the data in Table 2, the tensile strength of Examples 7-9 is higher than that of Examples 2 and 6, indicating that the present invention improves the tensile strength of the overhead insulated cable sheath layer by compounding the first polycarbonate and the second polycarbonate.

[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. An aging-resistant overhead insulated cable, characterized in that, From the inside out, it includes a conductor, a shielding layer, an insulation layer, and a sheath layer; the conductor is made of multiple stranded wires; the raw materials of the sheath layer include the following components by weight: 70-80 parts styrene-butadiene rubber, 20-30 parts nitrile rubber, 15-20 parts polycarbonate, 30-40 parts filler, 2-4 parts antioxidant, 3-5 parts aromatic oil, 1-3 parts vulcanizing agent, 3-5 parts activator, and 2-4 parts accelerator.

2. The aging-resistant overhead insulated cable according to claim 1, characterized in that, The conductor may be an aluminum alloy conductor or a copper alloy conductor.

3. The aging-resistant overhead insulated cable according to claim 1, characterized in that, The shielding layer is a metal shielding layer.

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

5. The aging-resistant overhead insulated cable according to claim 1, characterized in that, The filler is calcium silicate composite zirconium dioxide.

6. The aging-resistant overhead insulated cable according to claim 5, characterized in that, The preparation method of the calcium silicate composite zirconium dioxide includes the following steps: A1. After dispersing calcium silicate evenly in a solvent, add a surfactant and mix to obtain premixed solution I; A2. After adding zirconium oxychloride octahydrate to the premixed solution I and mixing, premixed solution II is obtained; A3. After adjusting the pH of the premixed solution II to 10-11, continue mixing, and then aging, filtering, and drying to obtain the calcium silicate composite zirconium dioxide.

7. The aging-resistant overhead insulated cable according to claim 6, characterized in that, The mass ratio of calcium silicate to zirconium oxychloride octahydrate is 7:3~4.

8. The aging-resistant overhead insulated cable according to claim 6, characterized in that, In step A1, the mixing temperature is 35~45℃ and the mixing time is 1.5~2.5h; in step A2, the mixing temperature is 35~45℃ and the mixing time is 1~2h.

9. The aging-resistant overhead insulated cable according to claim 6, characterized in that, The mass ratio of calcium silicate to surfactant is 100:5~7.

10. An aging-resistant overhead insulated cable according to claim 6, characterized in that, In step A3, the aging time is 1 to 2 hours.

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