High-strength Z-shaped expanded-diameter overhead insulated cable

Abstract

The invention relates to the technical field of cables, and provides a high-strength Z-shaped expanded-diameter aerial insulated cable which sequentially comprises a Z-shaped expanded-diameter conductor, a shielding layer, an insulating layer and a sheath layer from inside to outside. The Z-shaped diameter-expanded conductor comprises a diameter-expanded aluminum tube and a Z-shaped wire conductive layer twisted on the outer side of the diameter-expanded aluminum tube. According to the technical scheme, the problem that the mechanical property of the aerial insulated cable is insufficient in the related technology is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cable, in particular, it relates to a high-strength Z-shaped expanding overhead insulated cable. BACKGROUND

[0002] The core feature of the Z-shaped expanding overhead insulated cable is that through the Z-shaped conductor structure and the expanding design, the transmission efficiency and the insulation performance are ensured, and the weight of the cable itself and the line loss are significantly reduced, so that the Z-shaped expanding overhead insulated cable is widely applied in overhead transmission lines.

[0003] At present, there are many sheath layer materials for overhead insulated cables, such as chlorosulfonated polyethylene, silicone rubber, polyvinyl chloride or cross-linked polyethylene, etc. Among them, cross-linked polyethylene is a high-performance high molecular material with three-dimensional network cross-linked structure. This kind of material not only has high heat deformation resistance and mechanical strength, but also has excellent electrical insulation performance and good chemical corrosion resistance, and has become a commonly used sheath layer material in this field.

[0004] However, when the overhead cable bears overhead tension, the Z-shaped expanding conductor structure of the overhead insulated cable will transmit greater mechanical stress to the whole cable, and the sheath layer is easy to produce micro-cracks and stress damage, so higher requirements are put forward for the mechanical properties of the sheath layer. Therefore, it is of great significance to prepare a high-strength Z-shaped expanding overhead insulated cable for promoting the development of Z-shaped expanding overhead cable. SUMMARY

[0005] The present application provides a high-strength Z-shaped expanding overhead insulated cable, which solves the problem of insufficient mechanical properties of the overhead insulated cable in the related art.

[0006] The technical scheme of the present application is as follows: The present application provides a high-strength Z-shaped expanding overhead insulated cable, which is sequentially arranged from inside to outside as a Z-shaped expanding conductor, a shielding layer, an insulation layer and a sheath layer. The Z-shaped expanding conductor comprises an expanding aluminum pipe and a Z-shaped wire conductive layer twisted outside the expanding aluminum pipe.

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

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

[0009] As a further technical solution, the raw materials of the sheath layer include the following components by weight: 80-90 parts of polyethylene, 25-35 parts of ethylene-vinyl acetate copolymer, 15-20 parts of nanofiller masterbatch, 5-7 parts of flame retardant, 3-5 parts of plasticizer, 1-2 parts of crosslinking agent, 1-2 parts of antioxidant, and 0.5-2.5 parts of lubricant. The raw materials of the nanofiller masterbatch include polyethylene, nano-graphene, carboxylated cellulose nanocrystals, titanate coupling agent, and methoxy polyethylene glycol amine.

[0010] This invention prepares a high-strength Z-type expanded diameter overhead insulated cable. The addition of nanofiller masterbatch improves the mechanical properties of the sheath layer of the Z-type expanded diameter overhead insulated cable. In related technologies, to improve the mechanical properties of the sheath layer, nanofillers are often directly added to the sheath layer material. However, direct addition of nanofillers can lead to agglomeration and uneven dispersion, resulting in unsatisfactory improvement in the mechanical properties of the sheath layer. The nanofiller masterbatch of this invention includes polyethylene, nano-graphene, carboxylated cellulose nanowhiskers, titanate coupling agent, and methoxy polyethylene glycol amine. The titanate coupling agent can effectively improve the compatibility between nano-graphene and polyethylene. The amino groups of methoxy polyethylene glycol amine can form hydrogen bonds with nano-graphene and carboxylated cellulose nanowhiskers, further improving the dispersion of nanofillers and the compatibility between the nanofiller masterbatch and the matrix. Therefore, the nanofiller masterbatch in this invention can fully exert the reinforcing effect of nanofillers, thereby improving the mechanical properties of the sheath layer and meeting the long-term operation requirements of Z-type expanded diameter overhead insulated cables.

[0011] The overhead insulated cable of this invention incorporates plasticizers into the raw materials of the sheath layer, which can act as lubricants and spacers between polymer molecules, effectively reducing the interaction forces between molecular chains and making the material easier to plasticize and mold during processing. At the same time, it can also alleviate the internal stress caused by temperature fluctuations and slight external disturbances during overhead laying and long-term use, thereby ensuring the insulation reliability and overall structural stability of the overhead insulated cable and extending its service life.

[0012] This invention relates to an overhead insulated cable that, by adding antioxidants to the raw materials of the sheath layer, effectively inhibits the thermo-oxidative aging of polyethylene and ethylene-vinyl acetate copolymer during processing and use. Under extrusion and long-term operating conditions, it can capture free radicals and decompose hydrogen peroxides, preventing the insulation material from becoming brittle, cracking, or experiencing a decline in electrical performance due to oxidation. This ensures that the overhead insulated cable maintains excellent mechanical strength and insulation stability even when subjected to heat, oxygen, and ultraviolet radiation in outdoor environments for extended periods, thereby extending the cable's service life.

[0013] As a further technical solution, the Z-shaped wire used in the Z-shaped conductive layer is an aluminum alloy Z-shaped wire.

[0014] As a further technical solution, the mass ratio of polyethylene, nanographene, carboxylated cellulose nanocrystals, titanate coupling agent and methoxy polyethylene glycol amine is 15:7:5:2:0.8~1.5, for example, it can be 15:7:5:2:0.8, 15:7:5:2:1, 15:7:5:2:1.2, 15:7:5:2:1.5, preferably 15:7:5:2:1.2.

[0015] In the sheath layer of the overhead insulated cable of this invention, the raw materials of the nanofiller masterbatch are limited to a mass ratio of polyethylene, nanographene, carboxylated cellulose nanofibers, titanate coupling agent, and methoxy polyethylene glycol amine of 65:7:5:2:0.8~1.5. This can further improve the mechanical properties of the overhead insulated cable sheath layer. If the amount of methoxy polyethylene glycol amine added is insufficient, its modifying effect on the nanofiller cannot be fully utilized, resulting in uneven dispersion of the filler in the masterbatch and the polymer matrix of the sheath layer, thereby reducing the mechanical properties of the sheath layer. If the amount added is too much, it may cause the filler to agglomerate again, resulting in poor dispersibility, which will reduce the mechanical properties of the overhead insulated cable sheath layer.

[0016] As a further technical solution, the preparation method of the nanofiller masterbatch includes the following steps: A1. After dispersing the titanate coupling agent and methoxy polyethylene glycol amine evenly in a solvent, add the nano-graphene, mix, and dry to obtain modified nano-graphene. A2. The modified graphene nanoparticles, polyethylene and carboxylated cellulose nanofibers are mixed and then melt-extruded to obtain nanofiller masterbatch.

[0017] As a further technical solution, in step A1, the solvent is anhydrous ethanol.

[0018] As a further technical solution, in step A1, the mixing temperature is 50°C and the mixing time is 2 hours.

[0019] As a further technical solution, the flame retardant includes one or both of magnesium hydroxide and aluminum hydroxide.

[0020] As a further technical solution, the plasticizer includes one or more of dioctyl phthalate, dioctyl adipate, and dibutyl phthalate.

[0021] As a further technical solution, the crosslinking agent includes dicumyl peroxide and tert-butyl peroxide.

[0022] In the sheath layer of the overhead insulated cable of this invention, dicumyl peroxide and tert-butyl peroxylaurate are used as a composite crosslinking agent to synergistically enhance the mechanical properties of the sheath layer. Due to their different activation temperatures, the two form a staged crosslinking. Tert-butyl peroxylaurate initiates crosslinking at a lower temperature, while dicumyl peroxide ensures deep crosslinking at a higher temperature to form a stable network. The synergy between the two results in a more uniform, dense, and perfect three-dimensional network structure between polyethylene molecular chains, which greatly improves the crosslinking density and crosslinking uniformity, thereby enhancing the mechanical properties of the sheath layer.

[0023] As a further technical solution, the mass ratio of dicumyl peroxide to tert-butyl peroxylaurate is 7:1 to 3, for example, it can be 7:1, 7:1.5, 7:2, or 7:3, preferably 7:2.

[0024] As a further technical solution, the antioxidant includes one or more of antioxidant 1010, antioxidant 1076, and antioxidant 168.

[0025] As a further technical solution, the lubricant includes one or more of polyethylene wax, butyl stearate, and ethylene bis-stearamide.

[0026] The working principle and beneficial effects of this invention are as follows: This invention produces a high-strength Z-shaped expanded-diameter overhead insulated cable. The synergistic effect of each layer enhances the overall mechanical strength. The Z-shaped expanded-diameter conductor serves as the core, with the expanded-diameter aluminum tube providing robust internal support, effectively resisting external pressure and bending deformation. The Z-shaped conductive layer stranded on its outer side enhances the conductor's tensile strength and stability through tight stranding, reducing loosening and thus improving the conductor's overall durability. The shielding layer not only provides electromagnetic shielding but also acts as an intermediate protective layer, preventing damage to the internal conductor from mechanical stress or environmental influences. The insulation layer provides reliable electrical insulation while buffering external impacts and resisting tearing, preventing mechanical weaknesses caused by insulation failure. The sheath layer, as the outermost protective layer, ensures the cable maintains high strength during long-term use. These layers work together to improve the cable's mechanical strength, making it suitable for high-intensity overhead environments. 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 embodiments: The polyethylene is low-density polyethylene, model: LB7000, manufacturer: LG Korea; Ethylene-vinyl acetate copolymer, model: 28400, manufacturer: LG Korea; Polyethylene wax, model: AC-6A, manufacturer: Honeywell, USA; Nano-graphene, average particle size, 100nm; Methoxylated polyethylene glycolamine, with a weight-average molecular weight of 5000; Carboxylated cellulose nanofibers, average diameter 5nm, average length 100nm, manufacturer: Guilin Qihong Technology Co., Ltd., model: C-CNCP99F.

[0029] Example 1 A high-strength Z-type expanded diameter overhead insulated cable comprises, from the inside out, a Z-type expanded diameter conductor, a shielding layer, an insulation layer, and a sheath layer; wherein the raw materials of the sheath layer include the following components by weight: 80 parts polyethylene, 25 parts ethylene-vinyl acetate copolymer, 15 parts nano-filler masterbatch, 5 parts magnesium hydroxide, 3 parts dioctyl phthalate, 1 part dicumyl peroxide, 1 part antioxidant 1010, and 0.5 parts polyethylene wax; The preparation method of nanofiller masterbatch includes the following steps: A1. Add titanate coupling agent NDZ-201 and methoxy polyethylene glycol amine to anhydrous ethanol and disperse evenly. Then add nano-graphene and mix at 50°C for 2 hours. After drying, modified nano-graphene is obtained. A2. Modified nano-graphene, polyethylene and carboxylated cellulose nanofibers are mixed and then melt-extruded to obtain nanofiller masterbatch, wherein the mass ratio of polyethylene, nano-graphene, carboxylated cellulose nanofibers, titanate coupling agent NDZ-201 and methoxy polyethylene glycol amine is 15:7:5:2:0.8. A method for manufacturing a high-strength Z-type expanded diameter overhead insulated cable includes the following steps: S1. Twisting aluminum alloy Z-shaped wires onto the outside of an expanded diameter aluminum tube to form a Z-shaped wire conductive layer, thus obtaining a Z-shaped expanded diameter conductor. S2. Wrap the copper strip braided shielding layer around the outside of the Z-shaped expanded diameter conductor to form a shielding layer; S3. Extruding the cross-linked polyethylene insulation layer onto the outside of the shielding layer to form an insulation layer; S4. After the raw materials of the sheath layer are mixed evenly, they are melt-blended and extruded through a twin-screw extruder to cover the outside of the insulation layer, thus obtaining a high-strength Z-type expanded diameter overhead insulated cable.

[0030] Example 2 A high-strength Z-type expanded diameter overhead insulated cable comprises, from the inside out, a Z-type expanded diameter conductor, a shielding layer, an insulation layer, and a sheath layer; wherein the raw materials of the sheath layer include the following components by weight: 85 parts polyethylene, 30 parts ethylene-vinyl acetate copolymer, 17 parts nanofiller masterbatch, 6 parts magnesium hydroxide, 4 parts dioctyl phthalate, 1.5 parts dicumyl peroxide, 1.5 parts antioxidant 1010, and 1.3 parts polyethylene wax; The preparation method of nanofiller masterbatch includes the following steps: A1. Add titanate coupling agent NDZ-201 and methoxy polyethylene glycol amine to anhydrous ethanol and water at a mass ratio of 7:1 and disperse evenly. Then add nano-graphene and mix at 50℃ for 2 hours. After drying, modified nano-graphene is obtained. A2. Modified nano-graphene, polyethylene and carboxylated cellulose nanofibers are mixed and then melt-extruded to obtain nanofiller masterbatch, wherein the mass ratio of polyethylene, nano-graphene, carboxylated cellulose nanofibers, titanate coupling agent NDZ-201 and methoxy polyethylene glycol amine is 15:7:5:2:0.8. A method for manufacturing a high-strength Z-type expanded diameter overhead insulated cable includes the following steps: S1. Twisting aluminum alloy Z-shaped wires onto the outside of an expanded diameter aluminum tube to form a Z-shaped wire conductive layer, thus obtaining a Z-shaped expanded diameter conductor. S2. Wrap the copper strip braided shielding layer around the outside of the Z-shaped expanded diameter conductor to form a shielding layer; S3. Extruding the cross-linked polyethylene insulation layer onto the outside of the shielding layer to form an insulation layer; S4. After the raw materials of the sheath layer are mixed evenly, they are melt-blended and extruded through a twin-screw extruder to cover the outside of the insulation layer, thus obtaining a high-strength Z-type expanded diameter overhead insulated cable.

[0031] Example 3 A high-strength Z-type expanded diameter overhead insulated cable comprises, from the inside out, a Z-type expanded diameter conductor, a shielding layer, an insulation layer, and a sheath layer; wherein the raw materials of the sheath layer include the following components by weight: 90 parts polyethylene, 35 parts ethylene-vinyl acetate copolymer, 20 parts nano-filler masterbatch, 7 parts magnesium hydroxide, 5 parts dioctyl phthalate, 2 parts dicumyl peroxide, 2 parts antioxidant 1010, and 2.5 parts polyethylene wax; The preparation method of nanofiller masterbatch includes the following steps: A1. Add titanate coupling agent NDZ-201 and methoxy polyethylene glycol amine to anhydrous ethanol and water at a mass ratio of 7:1 and disperse evenly. Then add nano-graphene and mix at 50℃ for 2 hours. After drying, modified nano-graphene is obtained. A2. Modified nano-graphene, polyethylene and carboxylated cellulose nanofibers are mixed and then melt-extruded to obtain nanofiller masterbatch, wherein the mass ratio of polyethylene, nano-graphene, carboxylated cellulose nanofibers, titanate coupling agent NDZ-201 and methoxy polyethylene glycol amine is 15:7:5:2:0.8. A method for manufacturing a high-strength Z-type expanded diameter overhead insulated cable includes the following steps: S1. Twisting aluminum alloy Z-shaped wires onto the outside of an expanded diameter aluminum tube to form a Z-shaped wire conductive layer, thus obtaining a Z-shaped expanded diameter conductor. S2. Wrap the copper strip braided shielding layer around the outside of the Z-shaped expanded diameter conductor to form a shielding layer; S3. Extruding the cross-linked polyethylene insulation layer onto the outside of the shielding layer to form an insulation layer; S4. After the raw materials of the sheath layer are mixed evenly, they are melt-blended and extruded through a twin-screw extruder to cover the outside of the insulation layer, thus obtaining a high-strength Z-type expanded diameter overhead insulated cable.

[0032] Example 4 The only difference between this embodiment and Example 1 is that the mass ratio of polyethylene, nanographene, carboxylated cellulose nanocrystals, titanate coupling agent NDZ-201, and methoxy polyethylene glycol amine is 15:7:5:2:1.2.

[0033] Example 5 The only difference between this embodiment and Example 1 is that the mass ratio of polyethylene, nanographene, carboxylated cellulose nanowhiskers, titanate coupling agent NDZ-201, and methoxy polyethylene glycol amine is 15:7:5:2:1.5.

[0034] Example 6 The only difference between this embodiment and Embodiment 1 is that dicumyl peroxide is replaced with an equal mass of tert-butyl peroxide.

[0035] Example 7 The only difference between this embodiment and Example 1 is that dicumyl peroxide is replaced with equal amounts of dicumyl peroxide and tert-butyl peroxylaurate in a mass ratio of 7:1.

[0036] Example 8 The only difference between this embodiment and Example 1 is that dicumyl peroxide is replaced with equal amounts of dicumyl peroxide and tert-butyl peroxylaurate in a mass ratio of 7:2.

[0037] Example 9 The only difference between this embodiment and Embodiment 1 is that dicumyl peroxide is replaced with equal amounts of dicumyl peroxide and tert-butyl peroxylaurate in a mass ratio of 7:3.

[0038] Example 10 The only difference between this embodiment and Example 1 is that the titanate coupling agent NDZ-201 is replaced with an equal mass of methoxy polyethylene glycol amine.

[0039] Example 11 The only difference between this embodiment and Example 1 is that the methoxy polyethylene glycolamine is replaced with an equal mass of titanate coupling agent NDZ-201.

[0040] Example 12 The only difference between this comparative example and Example 1 is that the preparation method of the nanofiller masterbatch includes the following steps: mixing and melt-extruding nanographene, polyethylene and carboxylated cellulose nanocrystals to obtain nanofiller masterbatch, wherein the mass ratio of polyethylene, nanographene and carboxylated cellulose nanocrystals is 15:7:5.

[0041] Experimental Example 1 The Z-type expanded diameter overhead insulated cable sheaths obtained in Examples 1-12 were tested according to the following method: Tensile strength and elongation at break: The tensile strength and elongation at break of the sheath layer were determined according to the methods in GB / T 2951.11-2008 "General Test Methods for Insulation and Sheath Materials of Cables and Optical Fibers - Part 11: General Test Methods - Thickness and Dimensional Measurement - Mechanical Properties Test". The test specimen was a dumbbell specimen with a thickness of 1.3 mm. The test results are shown in Tables 1 and 2 below. Table 1 Performance test results of Examples 1-5 and Examples 10-12

[0042] As shown in Table 1, the tensile strength and elongation at break of the sheath layer in Examples 1-5 are higher than those in Comparative Examples 1-3, indicating that the present invention can improve the mechanical properties of the sheath layer of Z-type expanded diameter overhead insulated cable by adding nanofiller masterbatch (the raw materials are composed of polyethylene, nano-graphene, carboxylated cellulose nanofibers, titanate coupling agent and methoxy polyethylene glycol amine) to the sheath layer.

[0043] Table 2 Performance test results of Examples 1 and 6-9

[0044] As shown in Table 2, the tensile strength of the sheath layer in Examples 7-9 is higher than that in Examples 1 and 6, indicating that the mechanical properties of the sheath layer of Z-type expanded diameter overhead insulated cable can be improved by adding diisopropylbenzene oxide and tert-butyl peroxylaurate to the sheath layer.

[0045] 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 high-strength Z-type expanded diameter overhead insulated cable, characterized in that, From the inside out, the structure consists of a Z-shaped expanded diameter conductor, a shielding layer, an insulating layer, and a sheath layer. The Z-shaped expanded diameter conductor includes an expanded diameter aluminum tube and a Z-shaped conductive layer stranded on the outside of the expanded diameter aluminum tube.

2. The high-strength Z-type expanded diameter overhead insulated cable according to claim 1, characterized in that, The shielding layer is a metal shielding layer.

3. A high-strength Z-type expanded diameter overhead insulated cable according to claim 1, characterized in that, The insulation layer is a cross-linked polyethylene insulation layer.

4. A high-strength Z-type expanded diameter overhead insulated cable according to claim 1, characterized in that, The raw materials of the sheath layer include the following components by weight: 80-90 parts of polyethylene, 25-35 parts of ethylene-vinyl acetate copolymer, 15-20 parts of nanofiller masterbatch, 5-7 parts of flame retardant, 3-5 parts of plasticizer, 1-2 parts of crosslinking agent, 1-2 parts of antioxidant, and 0.5-2.5 parts of lubricant. The raw materials of the nanofiller masterbatch include polyethylene, nano-graphene, carboxylated cellulose nanofibers, titanate coupling agent, and methoxy polyethylene glycol amine.

5. A high-strength Z-type expanded diameter overhead insulated cable according to claim 4, characterized in that, The mass ratio of polyethylene, nanographene, carboxylated cellulose nanofibers, titanate coupling agent, and methoxy polyethylene glycol amine in the nanofiller masterbatch raw material is 15:7:5:2:0.8~1.

5.

6. A high-strength Z-type expanded diameter overhead insulated cable according to claim 4, characterized in that, The preparation method of the nanofiller masterbatch includes the following steps: A1. After dispersing the titanate coupling agent and methoxy polyethylene glycol amine evenly in a solvent, add the nano-graphene, mix, and dry to obtain modified nano-graphene. A2. The modified graphene nanoparticles, polyethylene and carboxylated cellulose nanofibers are mixed and then melt-extruded to obtain nanofiller masterbatch.

7. A high-strength Z-type expanded diameter overhead insulated cable according to claim 4, characterized in that, The crosslinking agent includes dicumyl peroxide and tert-butyl peroxide.

8. A high-strength Z-type expanded diameter overhead insulated cable according to claim 7, characterized in that, The mass ratio of dicumyl peroxide to tert-butyl peroxide is 7:1~3.

9. A high-strength Z-type expanded diameter overhead insulated cable according to claim 4, characterized in that, The antioxidants include one or more of antioxidants 1010, antioxidant 1076, and antioxidant 168.

10. A high-strength Z-type expanded diameter overhead insulated cable according to claim 4, characterized in that, The lubricant includes one or more of polyethylene wax, butyl stearate, and ethylene bis-stearamide.

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