A waterproof and corrosion-resistant cable and a preparation method and application thereof

Abstract

The application relates to the technical field of cables, and discloses a waterproof and corrosion-resistant cable as well as a preparation method and application thereof. The waterproof and corrosion-resistant cable comprises a conductor, an insulating layer and a sheath layer which are sequentially arranged outside the conductor; the insulating layer comprises the following raw materials in parts by weight: 80-90 parts of low-density polyethylene and 20-30 parts of hydrophobic modified composite powder; the sheath layer comprises the following raw materials in parts by weight: 90-100 parts of PVC resin and 35-45 parts of hydrophobic modified composite powder; the raw materials of the hydrophobic modified composite powder comprise core-shell structure powder and hydrophobic silane in a mass ratio of 1:0.05-0.1; the shell of the core-shell structure powder is nano calcium carbonate, and the core is magnesium hydroxide. Through the technical scheme, the problem of poor waterproofness of the corrosion-resistant cable in the related art is solved.

Description

Technical Field

[0001] This invention relates to the field of cable technology, specifically to a waterproof and corrosion-resistant cable, its preparation method, and its application. Background Technology

[0002] Corrosion-resistant insulated power cables are important products in the power transmission field, especially suitable for corrosive environments such as chemical plants and coastal areas. By adding an anti-corrosion layer or spraying anti-corrosion paint on the outer sheath surface, or by introducing corrosion-resistant materials into the raw materials of the insulation and sheath layers to enhance corrosion resistance, the problem of ordinary cables easily expanding and cracking in corrosive environments has been solved to some extent. For example, invention patent application CN120809347A discloses a corrosion-resistant insulated power cable that improves the corrosion resistance of the power cable in strong acid and strong alkali environments by introducing magnesium hydroxide@calcium carbonate composite powder into the sheath and insulation layers.

[0003] However, in practical applications, many corrosive environments are often accompanied by high humidity, moisture penetration, and even underwater conditions (such as the ocean). While existing corrosion-resistant cables can resist chemical erosion, their water resistance is poor, allowing moisture to easily penetrate the interior through the micropores of the sheath, leading to conductor oxidation and corrosion, and reducing conductivity. Moisture also works synergistically with corrosive media to accelerate the aging and degradation of the insulation and sheath layers, shortening the cable's lifespan. Therefore, there is an urgent need to develop a cable that combines excellent water resistance and corrosion resistance. Summary of the Invention

[0004] This invention proposes a waterproof and corrosion-resistant cable, its preparation method, and its application, which solves the problem of poor waterproof performance of corrosion-resistant cables in related technologies.

[0005] The technical solution of the present invention is as follows: This invention proposes a waterproof and corrosion-resistant cable, comprising a conductor and an insulation layer and a sheath layer sequentially disposed outside the conductor; The insulating layer comprises the following raw materials in parts by weight: 80-90 parts of low-density polyethylene, 20-30 parts of hydrophobic modified composite powder, and 1.5-3 parts of crosslinking agent; The sheath layer comprises the following raw materials in parts by weight: 90-100 parts of PVC resin and 35-45 parts of hydrophobic modified composite powder; The raw materials for the hydrophobic modified composite powder include core-shell structured powder and hydrophobic silane in a mass ratio of 1:0.05~0.1. The outer shell of the core-shell structured powder is nano-calcium carbonate, and the core is magnesium hydroxide.

[0006] In this invention, the preparation method of the hydrophobic modified composite powder is as follows: hydrophobic silane is added to anhydrous ethanol, stirred evenly, and then core-shell structured powder is added. After ultrasonic treatment, the powder is dried to obtain the hydrophobic modified composite powder.

[0007] In this invention, the core-shell structured powder uses magnesium hydroxide as the core and nano-calcium carbonate as the shell. The two work together to improve the corrosion resistance of the cable. After modification with hydrophobic silane, the waterproof performance of the cable is improved.

[0008] Furthermore, the core-shell structured powder is prepared by the following method: silane coupling agent is added twice to zinc stearate-coated magnesium hydroxide to modify nano-calcium carbonate, and after grinding, it is passed through a 325-mesh sieve to obtain composite powder.

[0009] Furthermore, the preparation method of zinc stearate coated magnesium hydroxide is as follows: zinc stearate is heated to melt, and then preheated and dried magnesium hydroxide is added. After mixing, the mixture is cooled and sieved to obtain zinc stearate coated magnesium hydroxide.

[0010] The preparation method of silane coupling agent modified nano-calcium carbonate is as follows: add silane coupling agent KH560 to anhydrous ethanol, stir evenly, add nano-calcium carbonate, and then sonicate to obtain silane coupling agent modified nano-calcium carbonate.

[0011] As a further technical solution, the hydrophobic silane includes methyltrimethoxysilane, heptadecafluorodecyltrimethoxysilane, 3-aminopropyltriethoxysilane, or 3-aminopropyltrimethoxysilane or γ-methacryloyloxypropyltrimethoxysilane.

[0012] As a further technical solution, the hydrophobic silane includes γ-methacryloyloxypropyltrimethoxysilane.

[0013] In this invention, γ-methacryloxypropyltrimethoxysilane is used as a hydrophobic silane, which works synergistically with the silane coupling agent in the core-shell structure powder to not only improve the waterproofness of the cable, but also improve its corrosion resistance.

[0014] As a further technical solution, the insulating layer also includes the following raw materials in parts by weight: 10-20 parts of linear low-density polyethylene and 0.6-1 part of polyethylene wax.

[0015] In this invention, linear low-density polyethylene (LDPE) and polyethylene wax are introduced into the insulation layer. The linear LDPE, which has good compatibility with LDPE, is used to optimize the crystalline structure and crystalline integrity of LDPE and reduce micropores. The introduction of polyethylene wax improves the compatibility of the hydrophobic modified composite powder in the LDPE matrix and reduces the macropores at the interface between the hydrophobic modified composite powder and LDPE. The two work together to form a dense barrier layer in the insulation layer, thereby further improving the waterproof performance of the corrosion-resistant cable.

[0016] As a further technical solution, the linear low-density polyethylene has a melt index of ≤20g / 10min at 190℃ and 2.16kg.

[0017] In this invention, when the melt index of linear low-density polyethylene at 190℃ and 2.16kg is ≤20g / 10min, the waterproof performance of the corrosion-resistant cable is further improved. The melt index of linear low-density polyethylene at 190℃ and 2.16kg is ≤20g / 10min, for example, it can be 1g / 10min, 2g / 10min, 5g / 10min, 7g / 10min, 10g / 10min, or 20g / 10min.

[0018] As a further technical solution, the linear low-density polyethylene has a melt index of 2~5 g / 10 min at 190℃ and 2.16 kg.

[0019] As a further technical solution, the insulating layer also includes the following raw materials in parts by weight: 0.5-1 parts antioxidant, 0.5-1 parts zinc stearate, and 0.4-0.6 parts polyethylene wax.

[0020] In this invention, in order to improve the antioxidant and processability of the insulation layer, antioxidants, zinc stearate and polyethylene wax are also added to the insulation layer.

[0021] As a further technical solution, the sheath layer also includes the following raw materials in parts by weight: 1-2 parts antioxidant, 3-5 parts stabilizer, 15-20 parts plasticizer and 1-1.5 parts lubricant.

[0022] In this invention, in order to improve the antioxidant properties, processing properties and toughness of the sheath layer, antioxidants, stabilizers, lubricants and plasticizers are also added to the sheath layer.

[0023] Furthermore, the antioxidants include antioxidant 1010 and antioxidant 168 in a mass ratio of 2:1; the lubricant includes polyethylene wax containing calcium stearate in a mass ratio of 1:1; and the plasticizers include diisononyl phthalate and trioctyl acetyl citrate in a mass ratio of 3:1. The introduction of trioctyl acetyl citrate into the plasticizer further improves the waterproof performance of the sheath layer.

[0024] The present invention also proposes a method for preparing the aforementioned waterproof and corrosion-resistant cable, comprising the following steps: S1. Plasticize low-density polyethylene, add hydrophobic modified composite powder and knead, then add crosslinking agent and knead to obtain insulation layer masterbatch. S2. Preheat the conductor to 75~85°C, and extrude the insulating layer masterbatch to coat the surface of the conductor to form an insulating layer; S3. After mixing PVC resin and hydrophobic modified composite powder, the mixture is extruded and coated onto the outside of the insulation layer to obtain a waterproof and corrosion-resistant cable.

[0025] The present invention also proposes the application of the aforementioned waterproof and corrosion-resistant cable for use as an underwater cable.

[0026] The working principle and beneficial effects of this invention are as follows: This invention significantly improves the waterproof performance of corrosion-resistant cables by optimizing the raw materials of the insulation and sheath layers, as detailed below: (1) Hydrophobic modified composite powder is obtained by hydrophobic modification of core-shell structure powder with hydrophobic silane. The hydrophobic modified composite powder is added to both the insulation layer and the sheath layer, so that the cable is not only corrosion resistant, but also has good waterproof performance. (2) By adding hydrophobically modified composite powder in the insulation layer and the sheath layer in a gradient manner, that is, the amount of hydrophobically modified composite powder added in the sheath layer is greater than that in the insulation layer, the sheath layer not only has high strength, but also forms the first waterproof and corrosion resistant barrier in corrosive environments such as water and salt spray. The insulation layer not only has good electrical insulation performance, but also effectively blocks the corrosive medium from penetrating into the conductor when the sheath layer is damaged or the seal fails. The sheath layer and the insulation layer work together to form a double waterproof and corrosion resistant guarantee, which improves the service life and operational reliability of the cable in the corrosive environment of the load. 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] Unless otherwise specified in the following embodiments, The conductor is an aluminum conductor; The grade of low-density polyethylene is DFDA-7042; The PVC resin grade is SG5; The core-shell structured powder was prepared by the following method: 100 parts of magnesium hydroxide were preheated to 100℃ and dried for 10 min to obtain dried magnesium hydroxide; 30 parts of zinc stearate were heated to melt and then added to magnesium hydroxide, mixed at 350 rpm for 30 min, cooled and passed through a 200-mesh sieve to obtain zinc stearate-coated magnesium hydroxide; the mass ratio of magnesium hydroxide to zinc stearate was 10:3; 0.24 parts of silane coupling agent KH560 were added to 24 parts of anhydrous ethanol, dissolved, and then 12 parts of nano-calcium carbonate were added, and ultrasonically treated at 300W and 55℃ for 20 min to obtain silane coupling agent modified nano-calcium carbonate; half the mass of silane coupling agent modified nano-calcium carbonate was added to zinc stearate-coated magnesium hydroxide, ground at 30 Hz for 12 min, and then the remaining silane coupling agent modified nano-calcium carbonate was added, ground at 40 Hz for 18 min, and after discharge, passed through a 325-mesh sieve to obtain the core-shell structured powder; The antioxidants are antioxidant 1010 and antioxidant 168 in a mass ratio of 2:1; The lubricant is polyethylene wax containing calcium stearate in a 1:1 mass ratio, and the polyethylene wax type is D1100. The plasticizers are diisononyl phthalate and trioctyl acetyl citrate in a mass ratio of 3:1; The crosslinking agent is dicumyl peroxide; The stabilizer is a calcium-zinc composite stabilizer; Linear low-density polyethylene includes the following grades: LLDPE M500026 has a melt index of 50 g / 10 min at 190℃ and 2.16 kg. LLDPE LL6101 has a melt index of 20 g / 10 min at 190℃ and 2.16 kg. LLDPE YR644 has a melt index of 5 g / 10 min at 190℃ and 2.16 kg. LLDPE7042N has a melt index of 2 g / 10 min at 190℃ and 2.16 kg. The InnoPlus LL7810A has a melt flow index of 1 g / 10 min at 190°C and 2.16 kg.

[0029] Example 1 A waterproof and corrosion-resistant cable includes a conductor and an insulation layer and a sheath layer sequentially disposed outside the conductor; The insulation layer comprises the following raw materials in parts by weight: 80 parts low-density polyethylene, 20 parts hydrophobically modified composite powder, 0.5 parts antioxidant, 1.5 parts crosslinking agent, 0.4 parts polyethylene wax, and 0.5 parts zinc stearate; The sheath layer comprises the following raw materials in parts by weight: 90 parts PVC resin, 35 parts hydrophobic modified composite powder, 1 part antioxidant, 3 parts stabilizer, 15 parts plasticizer and 1 part lubricant; The raw materials for the hydrophobic modified composite powder include core-shell structured powder and hydrophobic silane in a mass ratio of 1:0.05. The outer shell of the core-shell structured powder is nano-calcium carbonate, the core is magnesium hydroxide, and the hydrophobic silane is methyltrimethoxysilane.

[0030] The preparation method of hydrophobic modified composite powder is as follows: 0.05 parts of hydrophobic silane are added to 5 parts of anhydrous ethanol, stirred evenly, and then 1 part of core-shell structure powder is added. After ultrasonic treatment at 300W and 55℃ for 20 minutes, the powder is dried to obtain hydrophobic modified composite powder.

[0031] A method for preparing a waterproof and corrosion-resistant cable includes the following steps: S1. After plasticizing low-density polyethylene at 110℃, add antioxidant, polyethylene wax, zinc stearate and hydrophobic modified composite powder and mix for 9 minutes. Cool down to 100℃, add crosslinking agent, mix for 4 minutes and discharge. Extrude and granulate at 120℃ to obtain insulation layer masterbatch. S2. Preheat the conductor copper to 75°C, extrude the insulating masterbatch to coat the surface of the conductor copper to form an insulating layer, cool it with water at 60°C, then treat it with saturated steam at 165°C for 12 minutes to crosslink it, and then cool it to room temperature. S3. Mix PVC resin with hydrophobic modified composite powder, antioxidant, stabilizer, plasticizer and lubricant at 110℃ for 15 minutes, cool and discharge to obtain sheath layer mixture. Extrude the sheath layer mixture to cover the outside of the insulation layer to obtain waterproof and corrosion resistant cable.

[0032] Example 2 A waterproof and corrosion-resistant cable includes a conductor and an insulation layer and a sheath layer sequentially disposed outside the conductor; The insulation layer comprises the following raw materials in parts by weight: 90 parts low-density polyethylene, 30 parts hydrophobic modified composite powder, 1 part antioxidant, 3 parts crosslinking agent, 0.6 parts polyethylene wax, and 1 part zinc stearate; The sheath layer comprises the following raw materials in parts by weight: 100 parts PVC resin, 45 parts hydrophobic modified composite powder, 2 parts antioxidant, 5 parts stabilizer, 20 parts plasticizer, and 1.5 parts lubricant; The raw materials for the hydrophobic modified composite powder include core-shell structured powder and hydrophobic silane in a mass ratio of 1:0.1. The outer shell of the core-shell structured powder is nano-calcium carbonate, the core is magnesium hydroxide, and the hydrophobic silane is methyltrimethoxysilane.

[0033] The preparation method of hydrophobic modified composite powder is as follows: 0.1 parts of hydrophobic silane are added to 5 parts of anhydrous ethanol, stirred evenly, and then 1 part of core-shell structured powder is added. After ultrasonic treatment at 300W and 55℃ for 20 minutes, the powder is dried to obtain hydrophobic modified composite powder.

[0034] The preparation method of the waterproof and corrosion-resistant cable is the same as in Example 1.

[0035] Example 3 The only difference between this embodiment and Example 1 is that the hydrophobic silane is 3-aminopropyltrimethoxysilane.

[0036] Example 4 The only difference between this embodiment and Example 1 is that the hydrophobic silane is γ-methacryloyloxypropyltrimethoxysilane.

[0037] Example 5 A waterproof and corrosion-resistant cable includes a conductor and an insulation layer and a sheath layer sequentially disposed outside the conductor; The insulation layer comprises the following raw materials in parts by weight: 80 parts low-density polyethylene, 10 parts linear low-density polyethylene, 20 parts hydrophobically modified composite powder, 0.5 parts antioxidant, 1.5 parts crosslinking agent, 1 part polyethylene wax, and 0.5 parts zinc stearate; the linear low-density polyethylene is LLDPE M500026. The sheath layer comprises the following raw materials in parts by weight: 90 parts PVC resin, 35 parts hydrophobic modified composite powder, 1 part antioxidant, 3 parts stabilizer, 15 parts plasticizer and 1 part lubricant; The raw materials for the hydrophobic modified composite powder include core-shell structured powder and hydrophobic silane in a mass ratio of 1:0.05. The outer shell of the core-shell structured powder is nano-calcium carbonate, the core is magnesium hydroxide, and the hydrophobic silane is γ-methacryloyloxypropyltrimethoxysilane.

[0038] The preparation method of hydrophobic modified composite powder is as follows: 0.05 parts of hydrophobic silane are added to 5 parts of anhydrous ethanol, stirred evenly, and then 1 part of core-shell structure powder is added. After ultrasonic treatment at 300W and 55℃ for 20 minutes, the powder is dried to obtain hydrophobic modified composite powder.

[0039] A method for preparing a waterproof and corrosion-resistant cable includes the following steps: S1. After plasticizing low-density polyethylene at 110℃, add linear low-density polyethylene, antioxidant, polyethylene wax, zinc stearate and hydrophobic modified composite powder and mix for 9 minutes. Cool down to 100℃, add crosslinking agent, mix for 4 minutes and discharge. Extrude and granulate at 120℃ to obtain insulation layer masterbatch. S2. Preheat the conductor copper to 75°C, extrude the insulating masterbatch to coat the surface of the conductor copper to form an insulating layer, cool it with water at 60°C, then treat it with saturated steam at 165°C for 12 minutes to crosslink it, and then cool it to room temperature. S3. Mix PVC resin with hydrophobic modified composite powder, antioxidant, stabilizer, plasticizer and lubricant at 110℃ for 15 minutes, cool and discharge to obtain sheath layer mixture. Extrude the sheath layer mixture to cover the outside of the insulation layer to obtain waterproof and corrosion resistant cable.

[0040] Example 6 A waterproof and corrosion-resistant cable includes a conductor and an insulation layer and a sheath layer sequentially disposed outside the conductor; The insulation layer comprises the following raw materials in parts by weight: 90 parts low-density polyethylene, 20 parts linear low-density polyethylene, 30 parts hydrophobic modified composite powder, 1 part antioxidant, 3 parts crosslinking agent, 1.6 parts polyethylene wax, and 1 part zinc stearate; the linear low-density polyethylene is LLDPE M500026. The sheath layer comprises the following raw materials in parts by weight: 100 parts PVC resin, 45 parts hydrophobic modified composite powder, 2 parts antioxidant, 3 parts stabilizer, 20 parts plasticizer, and 1.5 parts lubricant; The raw materials for the hydrophobically modified composite powder include a core-shell structure powder and a hydrophobic silane in a mass ratio of 1:0.1. The outer shell of the core-shell structure powder is nano-calcium carbonate, the core is magnesium hydroxide, and the hydrophobic silane is γ-methacryloyloxypropyltrimethoxysilane.

[0041] The preparation method of hydrophobic modified composite powder is as follows: 0.1 parts of hydrophobic silane are added to 5 parts of anhydrous ethanol, stirred evenly, and then 1 part of core-shell structured powder is added. After ultrasonic treatment at 300W and 55℃ for 20 minutes, the powder is dried to obtain hydrophobic modified composite powder.

[0042] The preparation method of the waterproof and corrosion-resistant cable is the same as in Example 5.

[0043] Example 7 The only difference between this embodiment and Embodiment 6 is that 0.6 parts of polyethylene wax are added to the insulating layer.

[0044] Example 8 The only difference between this embodiment and Embodiment 6 is that the linear low-density polyethylene is LLDPE LL6101.

[0045] Example 9 The only difference between this embodiment and Embodiment 6 is that the linear low-density polyethylene is LLDPE YR644.

[0046] Example 10 The only difference between this embodiment and Embodiment 6 is that the linear low-density polyethylene is model LLDPE7042N.

[0047] Example 11 The only difference between this embodiment and Embodiment 6 is that the linear low-density polyethylene is InnoPlus LL7810A.

[0048] Comparative Example 1 The only difference between this comparative example and Example 1 is that the hydrophobic modified composite powder of the insulating layer and the sheath layer is replaced with an equal amount of core-shell structure powder.

[0049] The waterproof and corrosion resistance properties of the cable sheaths in Examples 1-4 and Comparative Example 1 were tested using the following methods: (1) Waterproof performance: The waterproof performance of the sheath layer was tested according to the electrical test methods in GB / T2951.13-2008 "General Test Methods for Insulation and Sheath Materials of Cables and Optical Cables Part 13: General Test Methods - Density Determination Methods - Water Absorption Test - Shrinkage Test"; (2) Corrosion resistance: The sheath sheet (100mm×100mm×2mm) was placed in 20% H2SO4 and 20% NaOH solution, soaked at 23℃ for 168h, rinsed with clean water, and dried with filter paper. The mass change rate was then tested. The test results are shown in Table 1 below: Table 1. Waterproof and corrosion-resistant properties of cable sheaths in Examples 1-4 and Comparative Example 1

[0050] As can be seen from Table 1, compared with Comparative Example 1, the waterproof performance of the cable sheath layer in Examples 1-4 is significantly improved, indicating that the use of hydrophobic modified composite powder in this invention significantly improves the waterproof performance of the cable. Compared with Examples 1-3, the corrosion resistance of the cable sheath layer in Example 4 is improved, indicating that the use of γ-methacryloyloxypropyltrimethoxysilane as a hydrophobic silane not only improves the waterproof performance of the cable but also improves its corrosion resistance, reducing the mass change rate of the cable after immersion in acidic and alkaline solutions to below 1.0%.

[0051] Water resistance performance tests were conducted on the cable insulation layers of Examples 1-11. The water resistance performance of the insulation layers was tested according to the weight water absorption test method in GB / T2951.13-2008 "General Test Methods for Insulation and Sheath Materials of Cables and Optical Fibers Part 13: General Test Methods—Density Determination Methods—Water Absorption Test—Shrinkage Test". The test results are characterized by water absorption, as shown in Table 2 below: Table 2. Test results of waterproof performance of cable insulation layers in Examples 1-11

[0052] Compared with Example 1, the water absorption of the cable insulation layer in Example 5 is reduced. Compared with Example 2, the water absorption of the cable insulation layer in Example 6 is reduced. This indicates that, based on Examples 1 and 2, increasing the content of polyethylene wax and adding linear low-density polyethylene in the insulation layer significantly improves the waterproof performance of the cable.

[0053] Compared with Example 7, the water absorption of the cable insulation layer in Example 6 was reduced, indicating that by adding the content of polyethylene wax to the insulation layer in addition to linear low-density polyethylene, the waterproof performance of the cable was further improved.

[0054] Compared to Example 6, the water absorption of the cable insulation layer in Examples 8-11 decreased, indicating that linear low-density polyethylene with a melt index ≤20g / 10min at 190℃ and 2.16kg further improved the waterproof performance of the cable. The water absorption of the cable insulation layer in Examples 9-10 decreased to 1mg / cm³. 2The following conditions apply: when the melt index of linear low-density polyethylene at 190℃ and 2.16kg is 2~5g / 10min, the cable has better waterproof performance.

[0055] 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 waterproof and corrosion-resistant cable, characterized in that, It includes a conductor and an insulating layer and a sheath layer sequentially disposed outside the conductor; The insulating layer comprises the following raw materials in parts by weight: 80-90 parts of low-density polyethylene, 20-30 parts of hydrophobic modified composite powder, and 1.5-3 parts of crosslinking agent; The sheath layer comprises the following raw materials in parts by weight: 90-100 parts of PVC resin and 35-45 parts of hydrophobic modified composite powder; The raw materials for the hydrophobic modified composite powder include core-shell structured powder and hydrophobic silane in a mass ratio of 1:0.05~0.

1. The outer shell of the core-shell structured powder is nano-calcium carbonate, and the core is magnesium hydroxide.

2. The waterproof and corrosion-resistant cable according to claim 1, characterized in that, The hydrophobic silanes include methyltrimethoxysilane, heptadecafluorodecyltrimethoxysilane, 3-aminopropyltriethoxysilane, or 3-aminopropyltrimethoxysilane or γ-methacryloyloxypropyltrimethoxysilane.

3. The waterproof and corrosion-resistant cable according to claim 1, characterized in that, The hydrophobic silane includes γ-methacryloyloxypropyltrimethoxysilane.

4. The waterproof and corrosion-resistant cable according to claim 1, characterized in that, The insulating layer also includes the following raw materials in parts by weight: 10-20 parts of linear low-density polyethylene and 0.6-1 part of polyethylene wax.

5. A waterproof and corrosion-resistant cable according to claim 4, characterized in that, The linear low-density polyethylene has a melt index of ≤20g / 10min at 190℃ and 2.16kg.

6. A waterproof and corrosion-resistant cable according to claim 5, characterized in that, The linear low-density polyethylene has a melt index of 2~5 g / 10 min at 190℃ and 2.16 kg.

7. A waterproof and corrosion-resistant cable according to any one of claims 1 to 6, characterized in that, The insulating layer also includes the following raw materials in parts by weight: 0.5 to 1 part antioxidant, 0.5 to 1 part zinc stearate, and 0.4 to 0.6 parts polyethylene wax.

8. A waterproof and corrosion-resistant cable according to any one of claims 1 to 6, characterized in that, The sheath layer also includes the following raw materials in parts by weight: 1-2 parts antioxidant, 3-5 parts stabilizer, 15-20 parts plasticizer and 1-1.5 parts lubricant.

9. A method for preparing a waterproof and corrosion-resistant cable according to any one of claims 1 to 6, characterized in that, Includes the following steps: S1. Plasticize low-density polyethylene, add hydrophobic modified composite powder and knead, then add crosslinking agent and knead to obtain insulation layer masterbatch. S2. The conductor is preheated to 75~85°C, and the insulating layer masterbatch is extruded and coated on the surface of the conductor to form an insulating layer. S3. After mixing PVC resin and hydrophobic modified composite powder, the mixture is extruded and coated onto the outside of the insulation layer to obtain a waterproof and corrosion-resistant cable.

10. The application of a waterproof and corrosion-resistant cable according to any one of claims 1 to 8 or a waterproof and corrosion-resistant cable prepared by the method according to claim 9, characterized in that, Used for underwater cables.

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