Recyclable polyethylene cable sheath material, recyclable polyethylene cable as well as preparation method and application of recyclable polyethylene cable

Abstract

According to the recoverable polyethylene cable sheath material, the recoverable polyethylene cable and the preparation method and application of the recoverable polyethylene cable sheath material, the recoverable polyethylene cable sheath material has the advantages that the obtained recoverable polyethylene cable sheath material has excellent mechanical performance, processing performance, weather resistance and corrosion resistance, and can meet IEC and HD standards at the same time; the environment pollution caused by waste discharge is reduced, the raw material cost of cable production is reduced, and the resource utilization efficiency is improved; the aluminum-plastic composite tape with radial water-blocking performance is matched, so that water can be prevented from permeating along the radial direction of the cable in a limited manner, and the possibility that the water enters the cable is greatly reduced, so that the influence of the water on the internal structure of the cable is reduced, and electrical parameters such as insulation resistance of the cable are kept in a relatively stable state; the probability of electrical faults caused by damp is reduced, the safety and reliability of the cable are improved, and the service life of the cable is prolonged.

Description

Technical Field

[0001] The invention belongs to the technical field of power cables, and in particular relates to a recyclable polyethylene cable sheath material, a recyclable polyethylene cable, and a preparation method and application thereof. Background Art

[0002] With the increasing awareness of environmental protection, the sustainable use of resources and the effective recycling of waste have become hot issues of global concern. In the cable manufacturing industry, polyethylene (PE) is widely used due to its excellent electrical, mechanical and chemical properties; however, improper disposal of polyethylene waste will not only cause environmental pollution, but also waste precious resources; therefore, the development of cable preparation technology with recyclable polyethylene sheath is of great significance to promote the green and sustainable development of the cable industry.

[0003] At present, recyclable polyethylene mainly comes from waste materials in the cable production process, dismantling of waste cables and polyethylene waste collected by recycling stations (such as beverage bottles, pipes and greenhouse films, etc.). After pre-treatment steps such as classification, cleaning and crushing, these wastes can be used to prepare recyclable polyethylene sheaths. The recycling methods of recyclable polyethylene include physical recycling and chemical recycling. Among them, physical recycling mainly reprocesses recycled polyethylene waste into new polyethylene materials through processes such as melting, filtering and extrusion; while chemical recycling converts polyethylene waste into monomers or oligomers through chemical reactions, and then further synthesizes new polyethylene materials.

[0004] However, there are a series of problems in the process of preparing cable sheaths from recyclable polyethylene; the first is the complex composition of waste polyethylene. Due to the wide range of sources of waste polyethylene, its composition and performance may vary greatly. In order to obtain recyclable polyethylene materials with stable performance, waste polyethylene needs to be strictly screened and classified to ensure the consistency of its composition; the second is quality control during the processing. During the processing of cable sheaths, the control of process parameters such as temperature, pressure, and speed is crucial to the quality and performance of the product; the last is the performance stability of the product. Cables with recyclable polyethylene sheaths may be affected by various factors such as temperature, humidity, and mechanical stress during long-term use, resulting in changes in their performance.

[0005] Due to the existence of the above-mentioned series of problems, it is difficult to meet the IEC and HD standards when using recyclable polyethylene resin as the sheath. Therefore, there are few reports on cables using recycled polyethylene as the sheath layer material.

[0006] Therefore, in response to the above problems, it is urgent to develop a recyclable polyethylene cable sheath material with excellent mechanical properties, weather resistance and corrosion resistance. Summary of the invention

[0007] In view of the deficiencies in the prior art, the object of the present invention is to provide a recyclable polyethylene cable sheath material, a recyclable polyethylene cable and a preparation method and application thereof. The recyclable polyethylene cable sheath material has excellent mechanical properties, processing properties, weather resistance and corrosion resistance, meets IEC and HD standards, and can ensure the safety, reliability and service life of the recyclable polyethylene cable further manufactured.

[0008] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a recyclable polyethylene cable sheath material, wherein the recyclable polyethylene cable sheath material comprises the following components in parts by weight:

[0010] 70-80 parts by weight of recyclable polyethylene resin;

[0011] 20-35 parts by weight of ethylene-vinyl acetate copolymer;

[0012] 2.5-3 parts by weight of carbon black;

[0013] 0.5-1 parts by weight of lubricant;

[0014] Antioxidant 0.2-0.7 parts by weight.

[0015] The recyclable polyethylene cable sheath material provided by the present invention comprises specific portions of recyclable polyethylene resin, ethylene-vinyl acetate copolymer, carbon black, lubricant and antioxidant. The above components are matched so that the obtained recyclable polyethylene cable sheath material can have excellent mechanical properties, processing properties, weather resistance and corrosion resistance, can meet IEC and HD standards at the same time, and can ensure the service life and safety and reliability of the recyclable polyethylene cable further manufactured.

[0016] Wherein, the amount of the recyclable polyethylene resin can be 70 parts by weight, 72 parts by weight, 74 parts by weight, 76 parts by weight, 78 parts by weight or 80 parts by weight, etc.

[0017] The amount of the ethylene-vinyl acetate copolymer can be 20 parts by weight, 22 parts by weight, 24 parts by weight, 26 parts by weight, 28 parts by weight, 30 parts by weight, 32 parts by weight, 34 parts by weight or 35 parts by weight.

[0018] The amount of carbon black can be 2.5 parts by weight, 2.6 parts by weight, 2.7 parts by weight, 2.8 parts by weight, 2.9 parts by weight or 3 parts by weight.

[0019] The amount of the lubricant can be 0.5 parts by weight, 0.6 parts by weight, 0.7 parts by weight, 0.8 parts by weight, 0.9 parts by weight or 1 part by weight, etc.

[0020] The antioxidant may be used in an amount of 0.2 parts by weight, 0.3 parts by weight, 0.4 parts by weight, 0.5 parts by weight, 0.6 parts by weight, or 0.7 parts by weight.

[0021] Preferably, the recyclable polyethylene resin is recovered from polyethylene plastic bottles and / or polyethylene greenhouse films.

[0022] In the present invention, there is no special requirement for the types of the lubricant and antioxidant, and conventional substances in the art may be selected.

[0023] In a second aspect, the present invention provides a method for preparing the recyclable polyethylene cable sheath material as described in the first aspect, the preparation method comprising: uniformly mixing recyclable polyethylene resin, ethylene-vinyl acetate copolymer, carbon black, lubricant and antioxidant to obtain the recyclable polyethylene cable sheath material.

[0024] In a third aspect, the present invention provides a recyclable polyethylene cable, the recyclable polyethylene cable comprising a conductor;

[0025] The conductor is sequentially coated with a conductor shielding layer, an insulating layer, an insulating shielding layer, a semiconductor water-resistant tape layer, an aluminum-plastic composite tape layer and a sheath layer;

[0026] The material of the sheath layer is the recyclable polyethylene cable sheath material as described in the first aspect.

[0027] The material of the sheath layer of the recyclable polyethylene cable provided by the present invention is the recyclable polyethylene cable sheath material as described in the first aspect, which has excellent weather resistance, corrosion resistance and mechanical properties, can meet the IEC and HD standards at the same time, and thus can ensure that the cable can pass the 3000h corrosion resistance test of HD 605 5.5; and when combined with the aluminum-plastic composite tape layer, it can not only effectively improve the electric field distribution, but also has excellent longitudinal water blocking function, meeting the requirements of IEC 60502-2 Appendix F experiment and radial water blocking performance.

[0028] Preferably, the conductor comprises a stranded aluminium conductor.

[0029] Preferably, the cross-sectional area of ​​the stranded aluminum conductor is 50 to 800 mm 2 , for example 50mm 2 , 100mm 2 , 200mm 2 、300mm 2 , 400mm 2 , 500mm 2 、600mm 2 、700mm 2 or 800mm 2Etc. Preferably, the material of the conductor shielding layer comprises a peroxide cross-linked semi-conductive polyolefin shielding material for conductors.

[0030] Preferably, the thickness of the conductor shielding layer is 0.5-1.2 mm, for example, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm or 1.2 mm.

[0031] Preferably, the material of the insulating layer includes cross-linked polyethylene.

[0032] Preferably, the thickness of the insulating layer is 2.5-8 mm, for example, 2.5 mm, 3.4 mm, 4.5 mm or 8 mm.

[0033] Preferably, the material of the insulating shielding layer includes a peroxide cross-linked strippable semi-conductive polyolefin shielding material for insulation.

[0034] Preferably, the thickness of the insulating shielding layer is 0.5-1.2 mm, for example, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm or 1.2 mm.

[0035] Preferably, the material of the semi-conductive tape layer includes a semi-conductive double-sided water-blocking tape.

[0036] Preferably, the thickness of the semiconductive tape layer is 0.25-0.35 mm, for example, 0.25 mm, 0.27 mm, 0.29 mm, 0.31 mm, 0.33 mm or 0.35 mm.

[0037] Preferably, the material of the aluminum-plastic composite tape layer is an aluminum-plastic composite tape.

[0038] Preferably, the thickness of the aluminum-plastic composite tape layer is 0.3-0.35 mm, for example, 0.3 mm, 0.31 mm, 0.32 mm, 0.33 mm, 0.34 mm or 0.35 mm.

[0039] Preferably, the thickness of the recyclable polyethylene sheath layer is 1.5-5 mm, for example, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm or 5 mm.

[0040] In a fourth aspect, the present invention provides a method for preparing the recyclable polyethylene cable as described in the third aspect, the preparation method comprising the following steps:

[0041] (1) Extruding the material of the conductor shielding layer, the material of the insulating layer and the material of the insulating shielding layer on the outside of the conductor in sequence to obtain a wire core;

[0042] (2) Wrapping the semi-conductive water-resistant tape around the cable core to obtain the cable core;

[0043] (3) longitudinally wrapping an aluminum-plastic composite tape around the cable core and extruding a recyclable polyethylene cable sheath material to obtain the recyclable polyethylene cable.

[0044] Preferably, step (3) specifically includes the following steps: converting the aluminum-plastic composite tape from an original flat plate to a tubular shape through a longitudinal wrapping airplane mold, thereby longitudinally wrapping the cable core, and then forming a flat and smooth structure through a shaping mold at the overlapping edges of the aluminum-plastic composite tape, thereby eliminating the "ruffles" at the longitudinal wrapping, and avoiding problems such as bulging on the surface of the subsequent sheath layer during extrusion; finally, extruding the recyclable polyethylene cable sheath material through an extruder to form a sheath layer; the recyclable polyethylene cable can be obtained through a one-step production, and the longitudinally wrapped aluminum-plastic composite tape and the outer sheath are continuously completed in the same process, so that the aluminum tape and the outer sheath are tightly bonded to achieve a better radial water-blocking effect.

[0045] Preferably, the extrusion of the recyclable polyethylene cable sheath material in step (3) is carried out during extrusion.

[0046] Preferably, the extruder adopts a long separated BM screw.

[0047] Preferably, the temperature of extruding the recyclable polyethylene cable sheath material in step (3) is 100-190°C, for example, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C or 190°C, etc.

[0048] In a fifth aspect, the present invention provides a use of the recyclable polyethylene cable as described in the third aspect in subway equipment, high-rise buildings or tunnels.

[0049] Compared with the prior art, the present invention has the following beneficial effects:

[0050] (1) The recyclable polyethylene cable sheath material provided by the present invention comprises a specific amount of recyclable polyethylene resin, ethylene-vinyl acetate copolymer, carbon black, lubricant and antioxidant; the above components are combined to make the obtained recyclable polyethylene cable sheath material have excellent mechanical properties, processing properties, weather resistance and corrosion resistance, and can meet IEC and HD standards at the same time;

[0051] (2) The recyclable polyethylene cable provided by the present invention adopts recyclable polyethylene cable sheath material as the material of the sheath layer, which not only has excellent wear resistance, corrosion resistance and weather resistance, but also can reduce environmental pollution, reduce the cost of raw materials for cable production, and improve resource utilization efficiency by recycling and reusing polyethylene waste; in addition, the excellent radial water-blocking performance of the aluminum-plastic composite tape layer can ensure the service life and safety and reliability of the cable. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 A schematic diagram of the cross-sectional structure of the recyclable polyethylene cable provided by the present invention;

[0053] Among them, 1-conductor, 2-conductor shielding layer, 3-insulating layer, 4-insulating shielding layer, 5-semiconductor water-blocking tape layer, 6-aluminum-plastic composite tape layer, 7-sheath layer. DETAILED DESCRIPTION

[0054] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0055] Unless otherwise specified, the raw materials involved in the following specific embodiments are all conventional materials in the art and can be purchased commercially;

[0056] In particular, some of the raw material information involved is as follows:

[0057] (1) Recyclable polyethylene resin A: recovered from polyethylene plastic bottles;

[0058] (2) Recyclable polyethylene resin B: recovered from polyethylene greenhouse film;

[0059] (3) Lubricant: purchased from Nanjing Tianshi, brand PEW-0319;

[0060] (4) Antioxidant: purchased from Beijing Jiyi, brand name AT-10.

[0061] Examples 1 to 4 and Comparative Examples 1 to 4

[0062] Examples 1 to 4 and Comparative Examples 1 to 4 respectively provide a recyclable polyethylene cable sheath material, the components included and the amounts of the components are shown in Table 1. In Table 1, the amount range of each component is "parts by weight";

[0063] Table 1

[0064]

[0065] The preparation method of the recyclable polyethylene cable sheath material provided in Examples 1 to 4 and Comparative Examples 1 to 4 comprises: mixing recyclable polyethylene resin, ethylene-vinyl acetate copolymer, carbon black, lubricant and antioxidant to obtain the recyclable polyethylene cable sheath material.

[0066] Comparative Example 5

[0067] A polyethylene cable sheath material, which differs from Example 1 only in that ordinary polyethylene resin is used to replace recyclable polyethylene resin A and ethylene-vinyl acetate copolymer, and other substances, amounts and preparation methods are the same as those in Example 1.

[0068] Application Example 1

[0069] A recyclable polyethylene cable, the cross-sectional structure diagram of which is as follows Figure 1 As shown, it comprises a conductor 1, and a conductor shielding layer 2, an insulating layer 3, an insulating shielding layer 4, a semi-conductive water-resistant tape layer 5, an aluminum-plastic composite tape layer 6 and a sheath layer 7 which are sequentially coated outside the conductor 1;

[0070] Among them, the cross-sectional area of ​​conductor 1 is 100mm 2 , is a stranded aluminum conductor;

[0071] The conductor shielding layer 2 has a thickness of 1.0 mm and is made of a peroxide cross-linked semi-conductive polyolefin shielding material for conductors;

[0072] The thickness of the insulating layer 3 is 5.5 mm, and the material is cross-linked polyethylene;

[0073] The thickness of the insulating shielding layer 4 is 1.0 mm, and the material is a peroxide cross-linked strippable semi-conductive polyolefin shielding material for insulation;

[0074] The thickness of the semi-conductive water-blocking tape layer 5 is 0.3 mm, and the material is a semi-conductive double-sided water-blocking tape;

[0075] The thickness of the aluminum-plastic composite tape layer 6 is 0.32 mm, and the material is an aluminum-plastic composite tape;

[0076] The thickness of the sheath layer 7 is 2.0 mm, and the material is the recyclable polyethylene cable sheath material provided in Example 1;

[0077] The preparation method of the recyclable polyethylene cable provided in this application example comprises the following steps:

[0078] (1) Extruding the material of the conductor shielding layer, the material of the insulating layer and the material of the insulating shielding layer on the outside of the conductor in sequence to obtain a wire core;

[0079] (2) Wrapping the semi-conductive water-resistant tape around the cable core to obtain the cable core;

[0080] (3) The aluminum-plastic composite tape is changed from the original flat plate to a tubular shape by a longitudinally wrapped airplane mold, and the cable core is longitudinally wrapped. Then, the overlapping edges of the aluminum-plastic composite tape are formed into a flat and smooth structure by a shaping die, and finally, the recyclable polyethylene cable sheath material is extruded by an extruder;

[0081] Among them, the temperature of the feeding port of the extruder is 100°C, the temperature of body zone 1 is 135°C, the temperature of body zone 2 is 170°C, the temperature of body zone 3 is 175°C, the temperature of body zone 4 is 175°C, the temperature of body zone 5 is 180°C, the temperature of flange zone is 190°C, the temperature of mold zone 1 is 180°C, the temperature of mold zone 2 is 185°C, the temperature of mold zone 3 is 185°C, and a long separation type BM screw is used.

[0082] Application Examples 2 to 4

[0083] A recyclable polyethylene cable, which differs from Application Example 1 in that the recyclable polyethylene cable sheath material provided by Examples 2 to 4 is used to replace the recyclable polyethylene cable sheath material provided by Example 1, and other structures, materials and preparation methods are the same as those of Application Example 1.

[0084] Comparative Application Examples 1 to 4

[0085] A recyclable polyethylene cable, which differs from Application Example 1 in that the recyclable polyethylene cable sheath material provided by Comparative Examples 1 to 4 is used to replace the recyclable polyethylene cable sheath material provided by Example 1, and other structures, materials and preparation methods are the same as those of Application Example 1.

[0086] Comparative Application Example 5

[0087] A polyethylene cable, which differs from Application Example 1 in that the polyethylene cable sheath material provided in Comparative Example 5 is used to replace the recyclable polyethylene cable sheath material provided in Example 1, and other structures, materials and preparation methods are the same as those in Application Example 1.

[0088] Comparative Application Example 6

[0089] A polyethylene cable, which differs from Application Example 1 in that a copper wire sparsely wound shield plus a conventional water-blocking tape metal shield is used to replace the aluminum-plastic composite tape, and other structures, materials and preparation methods are the same as those of Application Example 1.

[0090] Performance Testing:

[0091] (1) Performance test of cable sheath material

[0092] ①Tensile strength and elongation at break: Tested according to the method provided in GB / T 1040.3.

[0093] ② Weather resistance: Test according to the UV resistance test method provided in HD 605 2.4.23.

[0094] ③Alkali corrosion resistance: Tested with reference to the 3000h corrosion resistance test of HD 605 5.5.

[0095] ④ Sheath wear resistance: Refer to the wear resistance test provided in HD 605 2.4.22 for testing.

[0096] The cable sheath materials provided by Examples 1 to 4 and Comparative Examples 1 to 5 were tested according to the above test method, and the test results are shown in Table 2:

[0097] Table 2

[0098]

[0099] From the data in Table 2, we can see that:

[0100] The cable sheath materials provided in Examples 1 to 4 have excellent mechanical properties, weather resistance, corrosion resistance and wear resistance.

[0101] By comparing the data of Example 1 and Comparative Examples 1 to 2, it can be seen that excessive addition of recyclable polyethylene resin A (Comparative Example 1) will not further improve the performance of the obtained cable sheath material, but will cause its tensile strength to decrease; while too low an addition of recyclable polyethylene resin A (Comparative Example 2) will cause the mechanical properties of the obtained cable sheath material to decrease significantly, and the corrosion resistance and wear resistance tests will fail.

[0102] Comparing the data of Example 1 and Comparative Examples 3 to 4, it can be seen that too low or too high a dosage of carbon black will lead to a decrease in the mechanical properties of the resulting cable sheath material, and too low a dosage of carbon black will also cause the resulting cable sheath material to fail the weather resistance test.

[0103] Finally, by comparing the data of Example 1 and Comparative Example 5, it can be seen that the performance of the cable sheath material prepared by using the recyclable polyethylene resin is not much different from that of the cable sheath material prepared by using the ordinary polyethylene resin, and is even superior in mechanical properties.

[0104] (2) Performance test of the cable

[0105] ① Longitudinal water barrier: Test according to the method provided in Appendix F of IEC 60502-2.

[0106] ② Radial watertightness: Test according to the method provided in the 3000h radial watertightness test of HD 605 5.5.

[0107] ③ Partial discharge performance: Tested according to the method provided in GB / T 3048.12 partial discharge test.

[0108] According to the above test method, the cables provided in the corresponding application example 1 and the comparative application example 6 were tested. The test results are shown in Table 3:

[0109] Table 3

[0110]

[0111] According to the data in Table 3, we can see that:

[0112] Compared with the copper wire sparsely wound shielded cable provided in the comparative application 6, the longitudinally wrapped aluminum-plastic composite tape metal shielded cable provided in the application example 1 is superior in water blocking and partial discharge performance. The main reasons are as follows: the longitudinally wrapped metal shield is longitudinally wrapped with continuous aluminum foil to form a relatively seamless continuous structure; this is like a solid "wall" that can effectively prevent moisture from entering the cable from the radial direction, providing a more reliable radial water barrier for the cable; in addition, a relatively complete and seamless metal shielding layer also allows the electric field to be more effectively confined to a specific area inside the cable, and it is difficult for the electric field lines to pass through or penetrate from the gaps in the shielding layer. However, the copper wire sparsely wound shield is made of multiple copper wires, and there are many tiny gaps between the copper wires. These gaps provide possible channels for moisture to enter the cable, making it easier for external water to penetrate into the cable through these gaps, thereby reducing the water-blocking performance of the cable. Due to the gaps between the copper wires and the relatively loose structure, the ability to regulate the electric field distribution is relatively limited. It is difficult to efficiently disperse the concentrated electric field area like the longitudinal metal shield, so that the electric field strength may be high in some local areas, thereby increasing the possibility of partial discharge.

[0113] The applicant declares that the present invention illustrates a recyclable polyethylene cable sheath material, a recyclable polyethylene cable and its preparation method and application through the above embodiments, but the present invention is not limited to the above process steps, that is, it does not mean that the present invention must rely on the above process steps to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the raw materials selected by the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A recyclable polyethylene cable sheath material, characterized in that: The recyclable polyethylene cable sheath material comprises the following components in parts by weight: 70-80 parts by weight of recyclable polyethylene resin; 20-35 parts by weight of ethylene-vinyl acetate copolymer; 2.5-3 parts by weight of carbon black; 0.5-1 parts by weight of lubricant; Antioxidant 0.2-0.7 parts by weight.

2. The recyclable polyethylene cable sheath material according to claim 1, characterized in that: The recyclable polyethylene resin is recovered from polyethylene plastic bottles and / or polyethylene greenhouse films.

3. A method for preparing the recyclable polyethylene cable sheath material as claimed in claim 1 or 2, characterized in that: The preparation method comprises: uniformly mixing recyclable polyethylene resin, ethylene-vinyl acetate copolymer, carbon black, lubricant and antioxidant to obtain the recyclable polyethylene cable sheath material.

4. A recyclable polyethylene cable, characterized in that: The recyclable polyethylene cable comprises a conductor; The conductor is sequentially coated with a conductor shielding layer, an insulating layer, an insulating shielding layer, a semiconductor water-resistant tape layer, an aluminum-plastic composite tape layer and a sheath layer; The material of the sheath layer is the recyclable polyethylene cable sheath material as claimed in claim 1 or 2.

5. The recyclable polyethylene cable according to claim 4, characterized in that: The conductor comprises a stranded aluminum conductor; Preferably, the cross-sectional area of ​​the stranded aluminum conductor is 50 to 800 mm 2 ; Preferably, the material of the conductor shielding layer comprises a peroxide cross-linked semi-conductive polyolefin shielding material for conductors; Preferably, the thickness of the conductor shielding layer is 0.5 to 1.2 mm; Preferably, the material of the insulating layer includes cross-linked polyethylene; Preferably, the thickness of the insulating layer is 2.5-8.0 mm.

6. The recyclable polyethylene cable according to claim 4 or 5, characterized in that: The material of the insulating shielding layer includes a peroxide cross-linked strippable semi-conductive polyolefin shielding material for insulation; Preferably, the thickness of the insulating shielding layer is 0.5 to 1.2 mm; Preferably, the material of the semi-conductive tape layer comprises a semi-conductive double-sided water-blocking tape; Preferably, the thickness of the semi-conductive tape layer is 0.25 to 0.35 mm; Preferably, the material of the aluminum-plastic composite tape layer is an aluminum-plastic composite tape; Preferably, the thickness of the aluminum-plastic composite tape layer is 0.3 to 0.35 mm; Preferably, the thickness of the sheath layer is 1.5-5 mm.

7. A method for preparing a recyclable polyethylene cable as claimed in any one of claims 4 to 6, characterized in that: The preparation method comprises the following steps: (1) Extruding the material of the conductor shielding layer, the material of the insulating layer and the material of the insulating shielding layer on the outside of the conductor in sequence to obtain a wire core; (2) Wrapping the semi-conductive water-resistant tape around the cable core to obtain the cable core; (3) longitudinally wrapping an aluminum-plastic composite tape around the cable core and extruding a recyclable polyethylene cable sheath material to obtain the recyclable polyethylene cable.

8. The preparation method according to claim 7, characterized in that: Step (3) specifically includes the following steps: converting the aluminum-plastic composite tape from an original flat plate into a tubular shape by longitudinally wrapping an airplane mold, and longitudinally wrapping the cable core; then forming a flat and smooth structure at the overlapping edges of the aluminum-plastic composite tape by a shaping mold; and finally extruding the recyclable polyethylene cable sheath material by an extruder to obtain the recyclable polyethylene cable.

9. The preparation method according to claim 7 or 8, characterized in that: The temperature of extruding the recyclable polyethylene cable sheath material in step (3) is 100-190°C.

10. Use of the recyclable polyethylene cable according to any one of claims 1 to 6 in subway equipment, high-rise buildings, tunnels, photovoltaic power stations or wind power stations.

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