Salt-fog-resistant island cable and preparation method thereof

Abstract

The invention discloses a salt-fog-resistant island cable and a preparation method thereof, and belongs to the technical field of cables, the salt-fog-resistant island cable sequentially comprises a conductor, an insulating layer, a sheath layer, an armor layer and an outer sheath layer from inside to outside, the insulating layer comprises the following preparation raw materials: 100 parts of ethylene propylene diene monomer, 12-25 parts of modified sepiolite, 1-6 parts of a vulcanizing agent and 0.5-2 parts of a mildew preventive; and the outer sheath layer comprises the following preparation raw materials: 50-70 parts of polyarylene ether nitrile, 30-50 parts of TPU, 5-15 parts of nano boron nitride, 8-16 parts of modified montmorillonite, 4-12 parts of a light stabilizing aid and 0.3-2.5 parts of a lubricant. According to the invention, the insulation performance, mechanical strength and weather resistance of the cable in the island high salt mist and strong ultraviolet environment are synergistically improved, and the technical problems that a traditional cable is easy to corrode and the performance attenuation is fast are solved.

Description

Technical Field

[0001] This invention belongs to the field of cable technology, specifically a salt fog resistant island and reef cable and its preparation method. Background Technology

[0002] Tropical island and reef environments are characterized by high temperatures, high humidity, high salt spray, and strong solar radiation. These environmental factors pose a severe challenge to the durability of cables. Salt spray environments accelerate the corrosion of cable metal components, leading to decreased cable insulation performance, sheath aging, weakened mechanical strength, and even electrical faults.

[0003] Currently, conventional salt spray resistant cables mostly use simple galvanized steel wire armor and ordinary rubber sheaths. However, when these cables are exposed to the extreme environment of tropical islands and reefs for a long time, they still have problems such as insufficient resistance of metal components to salt spray corrosion, and the polymer sheath material is prone to aging and cracking under the combined action of strong ultraviolet rays and salt spray. Therefore, there is a need to develop a cable specifically designed for tropical island and reef environments with excellent salt spray resistance. Summary of the Invention

[0004] To overcome the aforementioned technical problems, this invention provides a salt spray resistant cable for islands and reefs, and its preparation method. This invention achieves a synergistic improvement in the cable's insulation performance, mechanical strength, and weather resistance under high salt spray and strong ultraviolet radiation environments on islands and reefs through a composite formulation of stearic acid-modified sepiolite and EPDM rubber in the insulation layer, and a synergistic system of polyarylene ether nitrile-TPU-nano boron nitride / modified montmorillonite in the outer sheath. This solves the technical problems of traditional cables being prone to corrosion and experiencing rapid performance degradation.

[0005] The present invention solves the above-mentioned technical problems through the following technical solutions.

[0006] This invention discloses a salt spray resistant island and reef cable, which comprises, from the inside out: a conductor, an insulation layer, a sheath layer, an armor layer, and an outer sheath layer. The insulation layer comprises the following raw materials in parts by weight: 100 parts EPDM rubber, 12-25 parts modified sepiolite, 1-6 parts vulcanizing agent, and 0.5-2 parts mildew inhibitor. The modified sepiolite is sepiolite treated with stearic acid coupling agent; The outer sheath layer comprises the following raw materials in parts by weight: 50-70 parts polyarylene ether nitrile, 30-50 parts TPU (thermoplastic polyurethane elastomer), 5-15 parts nano boron nitride, 8-16 parts modified montmorillonite, 4-12 parts light stabilizer and 0.3-2.5 parts lubricant. The modified montmorillonite is ammonium salt modified montmorillonite.

[0007] According to some embodiments of the present invention, the insulating layer comprises the following raw materials in parts by weight: 100 parts EPDM rubber, 15-20 parts modified sepiolite, 2-5 parts vulcanizing agent and 0.8-1.5 parts mildew inhibitor.

[0008] According to some embodiments of the present invention, the outer sheath layer comprises the following raw materials in parts by weight: 50-60 parts polyarylene ether nitrile, 30-40 parts TPU, 6-12 parts nano boron nitride, 10-15 parts modified montmorillonite, 5-10 parts light stabilizer and 0.5-2 parts lubricant.

[0009] According to some embodiments of the present invention, the density of the EPDM rubber is 1.8~1.9 g / cm³. 3 The optimal value is 1.85 g / cm³. 3 .

[0010] According to some embodiments of the present invention, the modified montmorillonite is at least one of octadecyl dimethyl benzyl ammonium chloride modified montmorillonite, octadecyl dimethyl ammonium chloride modified montmorillonite, bis(octadecyl dimethyl ammonium chloride) modified montmorillonite, octadecyl-2-ethylhexyl dimethyl ammonium chloride modified montmorillonite, and octadecyl dihydroxyethyl methyl ammonium chloride modified montmorillonite; preferably, it is octadecyl dimethyl benzyl ammonium chloride modified montmorillonite, octadecyl dimethyl ammonium chloride modified montmorillonite, or octadecyl-2-ethylhexyl dimethyl ammonium chloride modified montmorillonite.

[0011] According to some embodiments of the present invention, the vulcanization aid comprises 2.0 to 3.0 parts of peroxide vulcanizing agent and 1.0 to 2.0 parts of crosslinking accelerator; Further, the peroxide vulcanizing agent is at least one of dicumyl peroxide (DCP, CAS No.: 80-43-3) and 2,5-dimethyl-2,5-di-tert-butylperoxide (DBPMH, CAS No.: 78-63-7); Further, the crosslinking promoter is at least one of triallyl isocyanurate (TAIC, CAS No.: 1025-15-6) and trimethylolpropane triacrylate (TMPTA, CAS No.: 3290-92-4).

[0012] According to some embodiments of the present invention, the average particle size of the sepiolite is 2~10 μm.

[0013] According to some embodiments of the present invention, the antifungal agent is at least one of iodopropynyl butylcarbamate (IPBC, CAS No.: 55406-53-6) or 2-n-octyl-4-isothiazolin-3-one (OIT, CAS No.: 26530-20-1).

[0014] According to some embodiments of the present invention, the density of the TPU is 1.0~1.3 g / cm³. 3 The preferred concentration is 1.1~1.2 g / cm³. 3 .

[0015] According to some embodiments of the present invention, the diameter of the nano-boron nitride is 1~50nm, preferably 8~30nm.

[0016] According to some embodiments of the present invention, the light stabilizing agent is 2-4 parts of benzotriazole derivative, 2-4 parts of ultraviolet absorber, and 1-2 parts of light stabilizer.

[0017] Further, the benzotriazole derivative is at least one of benzotriazole (BTA, CAS: 95-14-7), methylbenzotriazole (TTA, CAS: 29385-43-1), and 5-carboxybenzotriazole (BTA-COOH, CAS: 23814-12-2).

[0018] Further, the ultraviolet absorber is at least one of 2-(2'-hydroxy-5'-methylphenyl)benzotriazole (UV-P, CAS: 2440-22-4), 2-hydroxy-4-n-octyloxybenzophenone (UV-531, CAS: 1843-05-6), and 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole (UV-326, CAS: 3896-11-5).

[0019] Further, the light stabilizer is at least one of bis(2,2,6,6-tetramethylpiperidinol) sebacate (light stabilizer 770, CAS No.: 52829-07-9), poly[[6-[(1,1,3,3-tetramethylbutyl)amino]-1,3,5-triazine-2,4-diyl][(2,2,6,6-tetramethyl-4-piperidinyl)imino]-1,6-hexadiyl[(2,2,6,6-tetramethyl-4-piperidinyl)imino]] (light stabilizer 944, CAS No.: 70624-18-9), and bis(2,2,6,6-tetramethylpiperidinyl) sebacate (light stabilizer 622, CAS No.: 70198-29-7).

[0020] According to some embodiments of the present invention, the lubricant is at least one of zinc stearate, calcium stearate, magnesium stearate, low molecular weight polyethylene wax, paraffin wax, and ethylene bis-stearamide (EBS), preferably zinc stearate.

[0021] According to some embodiments of the present invention, the volume resistivity of the insulating layer is ≥1×10⁻⁶. 15 Ω·m, preferably 1.0×10 15 ~1.3×1015 Ω·m.

[0022] According to some embodiments of the present invention, the elongation at break of the insulating layer is ≥200%, preferably 220~280%.

[0023] According to some embodiments of the present invention, the tensile strength of the insulating layer is ≥6.5MPa, preferably 6.5~8MPa.

[0024] According to some embodiments of the present invention, the elongation at break of the outer sheath layer is ≥280%, preferably 300~350%.

[0025] According to some embodiments of the present invention, the tensile strength of the outer sheath layer is ≥18.0 MPa, preferably 18~21 MPa.

[0026] According to some embodiments of the present invention, the conductor is made of multiple strands of tin-plated copper wire twisted together, and water-blocking paste may be filled between the strands.

[0027] Furthermore, the dropping point of the water-resistant paste is ≥150℃.

[0028] According to some embodiments of the present invention, the diameter of the tin-plated copper wire is 0.2~0.8mm, preferably 0.2~0.4mm.

[0029] According to some embodiments of the present invention, the pitch ratio of the stranding is 14.5 to 15.5 times.

[0030] According to some embodiments of the present invention, the sheath layer includes an inner aluminum-plastic composite strip longitudinal wrapping layer and an outer TPU inner sheath.

[0031] According to some embodiments of the present invention, the armor layer is composed of two galvanized steel wire layers, namely an inner galvanized steel wire layer and an outer galvanized steel wire layer.

[0032] According to some embodiments of the present invention, the twisting directions of the inner galvanized steel wire layer and the outer galvanized steel wire layer are opposite.

[0033] According to some embodiments of the present invention, the twisting pitch ratio of the inner galvanized steel wire layer is 14 to 15 times and the wire tension is 10 to 12 N.

[0034] According to some embodiments of the present invention, the twisting pitch ratio of the outer galvanized steel wire layer is 12 to 13 times and the wire tension is 12 to 15 N.

[0035] This invention also discloses a method for preparing salt spray resistant cables for islands and reefs, comprising the following steps: S1. After mixing and granulating the raw materials for preparing the insulating layer, the insulating layer is extruded onto the surface of the conductor and vulcanized to obtain a preform; S2. Aluminum-plastic composite strip is longitudinally wrapped around the surface of the preform to form an aluminum-plastic composite strip longitudinal wrapping layer; then TPU is extruded onto the surface of the aluminum-plastic composite strip longitudinal wrapping layer to form a TPU inner sheath; the two together constitute the sheath layer. S3. Two layers of galvanized steel wire with opposite twisting directions are wrapped around the surface of the sheath layer to form an armor layer; S4. After mixing the raw materials for the outer sheath layer, extrude them onto the surface of the armor layer to obtain a salt spray resistant island and reef cable.

[0036] S1 also includes the preparation process of the modified sepiolite, namely, dissolving stearic acid in ethanol to form a stearic acid coupling agent solution, and then stirring and modifying the sepiolite powder in the stearic acid coupling agent solution.

[0037] In further step S1, the mass fraction of the stearic acid coupling agent solution is 3-7%.

[0038] In further step S1, the mass ratio of sepiolite powder to stearic acid coupling agent solution is 1 to 3 / 1.

[0039] In S1, the mixing is carried out using an internal mixer at a temperature of 110~120℃, a pressure of 0.3~0.5MPa, and a rotation speed of 30~40r / min for 10~30min. Then, it is fed into a granulator and granulated at an extrusion temperature of 110~150℃ and a screw rotation speed of 25~35r / min to obtain insulating particles. In S1, the thickness of the extruded material is 1.5~2.0mm.

[0040] In S1, the extruded material is cooled in cooling water at 20~30℃ for 10~15 minutes.

[0041] In S1, the vulcanization is carried out at 160~170℃ for 15~20 minutes.

[0042] In S2, the vertical overlap rate is 15-20%.

[0043] In S2, the TPU extrusion is performed using an extruder with a barrel temperature of 170~180℃, a screw speed of 30~40r / min, and an extrusion thickness of 1.5~2.0mm. After extrusion, the TPU is cooled with 20~30℃ cooling water for 10~15min to form a TPU inner sheath.

[0044] In S4, the mixing process is as follows: polyarylene ether nitrile is vacuum plasticized at 168~172℃ for 10~15min, and the moisture content after plasticization is controlled to be ≤0.1%; then the other raw materials for the preparation of the outer sheath layer are added to a twin-screw extruder and mixed for 15~20min at a barrel temperature of 190~195℃, a screw speed of 40~50r / min, and a feeding speed of 20~30kg / h to obtain outer sheath granules; In step S4, the outer sheath particles are extruded onto the outside of the armor layer, with the extrusion thickness controlled at 2.5~3.5mm and the linear speed at 5~8m / min. After extrusion, the material is air-cooled at 20~30℃ for 10~15min.

[0045] Based on common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.

[0046] Compared with the prior art, the beneficial effects of the present invention are: Existing technologies mostly use EPDM rubber or ordinary inorganic fillers, which are insufficient in terms of salt spray resistance and mildew resistance. This invention utilizes a stearic acid-coupled modified sepiolite composite with EPDM rubber. The stearic acid coupling agent improves the interfacial compatibility between the filler and the rubber, while the layered structure of the sepiolite forms a physical barrier layer, blocking Cl- from salt spray. - penetration.

[0047] Existing cables designed for salt spray environments typically use single-layer PE, PVC, or ordinary TPU outer sheaths, which struggle to simultaneously achieve good weather resistance, mechanical strength, and chemical corrosion resistance. This invention employs a blend of chemically resistant and high-temperature resistant polyarylene ether nitrile (PAHNI) with TPU, further incorporating thermally conductive nano-boron nitride and ammonium salt-modified montmorillonite for interlayer barrier properties. This forms an organic / inorganic barrier network, which, combined with composite light-stabilizing agents, resists aging caused by strong ultraviolet radiation on islands and reefs. Attached Figure Description

[0048] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings.

[0049] Figure 1 This is a schematic diagram of the salt fog resistant island and reef cable structure of Example 1.

[0050] Explanation of reference numerals in the attached diagram: 1. Conductor; 2. Water-blocking compound; 3. Insulating layer; 4. Sheath layer; 5. Armor layer; 6. Outer sheath layer. Detailed Implementation

[0051] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0052] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0053] The raw material information used in the following examples is as follows: The grade of ethylene propylene diene monomer (EPDM) rubber is SK S6090F from South Korea, and its density is 1.85 g / cm³. 3 ; The grade of stearic acid is Wilmar Stearic Acid 1801; The dropping point of the water-resistant paste is 160℃; Polyarylene ether nitrile was purchased from Shandong Zengyi Biotechnology Co., Ltd. The modified montmorillonite was purchased from Zhejiang Fenghong New Materials Co., Ltd. Preparation process of modified sepiolite: Stearic acid coupling agent was dissolved in ethanol to prepare a 5% stearic acid coupling agent solution. Dry sepiolite powder was added to a constant-temperature stirred tank along with the sepiolite:stearic acid coupling agent solution:deionized water at a mass ratio of 100:53:200. The order of addition was as follows: sepiolite was added to the deionized water in batches and dispersed evenly. The stearic acid coupling agent solution was then slowly added to the dispersion tank at a flow rate of 5 L / min. The mixture was stirred at 85℃ (1000 r / min) for 30 min. After modification, the filter cake was collected by filtration, washed with deionized water, dried, and pulverized to obtain modified sepiolite with an average particle size of 8 μm. The TPU grade is BASF Elastollan 1185 A; This includes, but is not limited to, the models from the above manufacturers.

[0054] Example 1 The structure of the salt fog resistant island / reef cable in this embodiment is shown in [reference]. Figure 1 From the inside out, it includes: conductor 1, insulation layer 3, sheath layer 4, armor layer 5 and outer sheath layer 6, with water-blocking paste 2 filling the spaces between conductors 1.

[0055] Specifically, the structural layers are configured as follows: The conductor is made of 19 strands of tinned copper wire with a diameter of 0.3mm, with water-blocking paste filling the spaces between the strands; The insulation layer comprises the following raw materials in parts by weight: 100 parts EPDM rubber, 18 parts modified sepiolite, 4 parts vulcanizing aids (2.5 parts DCP and 1.5 parts TAIC) and 1.2 parts antifungal agent (IPBC). The sheath layer consists of an inner aluminum-plastic composite strip longitudinal wrapping layer and an outer TPU inner sheath; The armor layer consists of two layers of galvanized steel wire: a 1.2mm inner galvanized steel wire layer and a 1.4mm outer galvanized steel wire layer; the strands of the two galvanized steel wire layers are twisted in opposite directions. The outer sheath layer comprises the following raw materials in parts by weight: 65 parts polyarylene ether nitrile, 35 parts TPU, 8 parts nano boron nitride (20 nm in diameter), 10 parts modified montmorillonite (octadecyl dimethyl ammonium chloride modified montmorillonite), 7 parts light stabilizer (3 parts BTA, 3 parts UV-531 and 1 part light stabilizer 770) and 1.2 parts lubricant (zinc stearate).

[0056] The method for preparing the salt spray resistant island / reef cable in this embodiment is as follows: S1. Select tin-plated copper wire with a single wire diameter of 0.3mm, clean it with ultrasonic cleaning to remove surface oil, and dry it for later use; use 19 strands of tin-plated copper wire to strand together, with the stranding direction being right-handed, a pitch ratio of 15 (stretching length = 15 × conductor outer diameter), a pay-off tension of 8N, a take-up tension of 10N, and a stranding speed of 20m / min; uniformly fill the strands of the stranded conductor with water-blocking paste using a pressure-type paste injection machine at a pressure of 0.3MPa to ensure that the water-blocking paste completely covers each single wire without any gaps or residues; after take-up, let it stand for 24 hours to allow the water-blocking paste to fully impregnate it; The dried EPDM rubber, modified sepiolite, mildew inhibitor, and vulcanizing agent were sequentially added to a mixer and mixed. The mixture was then kneaded for 15 minutes at 110℃, 0.4MPa, and 35r / min. The mixture was then fed into a granulator and granulated at an extrusion temperature of 120-130℃ (barrel temperature settings: zone 1 120℃, zone 2 125℃, zone 3 130℃) and a screw speed of 30r / min to obtain insulating granules. The insulating granules are produced by extruding an insulating layer onto the conductor surface using an extruder. The barrel temperature is divided into sections: zone 1 115℃, zone 2 125℃, zone 3 130℃, and the die head 135℃. The screw speed is 30 r / min, the die head pressure is 18 MPa, and the extrusion thickness is 1.8 mm. After extrusion, the granules are first cooled with 25℃ cooling water for 12 minutes, and then sent to a vulcanizing tank for vulcanization at 165℃ and 0.7 MPa pressure for 18 minutes. After vulcanization, the granules are naturally cooled to room temperature to obtain the preform. S2. The prefabricated part is longitudinally wrapped with aluminum-plastic composite tape on the surface of the insulation layer with an overlap rate of 18% using a longitudinal wrapping machine. After longitudinal wrapping, it is shaped by hot press roller (temperature 120℃, pressure 0.2MPa) to ensure that the overlap is tightly attached without bubbles or wrinkles, forming an aluminum-plastic composite tape longitudinal wrapping layer. A TPU inner sheath is extruded onto the longitudinal wrapping layer of an aluminum-plastic composite strip using an extruder. The barrel temperature is divided into three zones: 170℃ in zone 1, 175℃ in zone 2, 180℃ in zone 3, and 185℃ at the die head. The screw speed is 35 r / min, and the extrusion thickness is 1.8 mm. After extrusion, the material is cooled with 25℃ cooling water for 10 minutes to form the TPU inner sheath. At this point, the sheath-covered part is obtained.

[0057] S3. Inner galvanized steel wire armor: The sheath layer covering is fed into the armoring machine, using 16 galvanized steel wires with a diameter of 1.2mm, twisted in the right direction, with a pitch ratio of 14.5 times, a wire tension of 11N, and a twisting speed of 8m / min, to ensure that the steel wires are evenly arranged and without crossing or loosening. Outer galvanized steel wire armor: 24 galvanized steel wires with a diameter of 1.4mm are used on the surface of the inner armor layer, twisted to the left (opposite to the inner layer), with a pitch ratio of 12.5, a wire tension of 13N, a twisting speed of 6m / min, and fixed with binding straps (500mm apart) after twisting to prevent the steel wires from shifting.

[0058] S4. Polyarylene ether nitrile was plasticized in a vacuum oven at 170℃ for 12 min (vacuum degree -0.095MPa), and the moisture content after plasticization was controlled to be ≤0.1%. Then, the raw materials for the outer sheath layer were added to a twin-screw extruder according to the other preparation methods. The barrel temperature was divided into three zones: Zone 1 190℃, Zone 2 192℃, Zone 3 195℃, and Die head 198℃. The screw speed was 45 r / min, the feeding speed was 25 kg / h, and after mixing for 18 min, the mixture was extruded and granulated to obtain outer sheath granules. The outer sheath granules were then extruded onto the surface of the armor layer using an extruder. The barrel temperature was divided into three zones: Zone 1 190℃, Zone 2 195℃, Zone 3 200℃, and Die head 205℃. The screw speed was 25 r / min, and the extrusion thickness was 3.0 mm. After extrusion, the mixture was cooled at 28℃ for 15 min and then kept at a constant temperature for 24 h to obtain a salt spray resistant cable for islands and reefs.

[0059] The volume resistivity of the insulating layer is 1.2 × 10⁻⁶. 15 Ω·m (test method refers to GB / T 1410-2006), elongation at break 220% (test method refers to GB / T 1040.2-2022), tensile strength 7.5MPa (test method refers to GB / T 1040.2-2022); The elongation at break of the outer sheath is 350% (test method refers to GB / T 1040.2-2022), and the tensile strength of the outer sheath is 18MPa (test method refers to GB / T 1040.2-2022).

[0060] Example 2 The difference between this embodiment and Embodiment 1 is as follows: The insulation layer comprises the following raw materials in parts by weight: 100 parts EPDM rubber, 13 parts modified sepiolite, 4 parts vulcanizing agent and 1.2 parts mildew inhibitor; The volume resistivity of the insulating layer is 1.1 × 10⁻⁶. 15 Ω·m, elongation at break 250%, tensile strength 6.8MPa; The other raw materials, steps and parameters are the same as in Example 1.

[0061] Example 3 The difference between this embodiment and Embodiment 1 is as follows: The outer sheath layer comprises the following raw materials in parts by weight: 70 parts polyarylene ether nitrile, 30 parts TPU, 8 parts nano boron nitride, 16 parts modified montmorillonite (octadecyl dimethyl benzyl ammonium chloride modified montmorillonite), 7 parts light stabilizer and 1.2 parts lubricant; The other raw materials, steps and parameters are the same as in Example 1.

[0062] The elongation at break of the outer sheath is 285%, and the tensile strength of the outer sheath is 20.2 MPa.

[0063] Example 4 The difference between this embodiment and Embodiment 1 is as follows: The outer sheath layer comprises the following raw materials in parts by weight: 70 parts polyarylene ether nitrile, 30 parts TPU, 15 parts nano boron nitride, 10 parts modified montmorillonite (octadecyl dimethyl ammonium chloride modified montmorillonite), 7 parts light stabilizer and 1.2 parts lubricant; The other raw materials, steps and parameters are the same as in Example 1.

[0064] The elongation at break of the outer sheath is 320%, and the tensile strength of the outer sheath is 19.5 MPa.

[0065] Example 5 The difference between this embodiment and Embodiment 1 is as follows: The modified montmorillonite used in this embodiment is octadecylbis(hydroxyethyl)methylammonium chloride modified montmorillonite; The other raw materials, steps and parameters are the same as in Example 1.

[0066] The elongation at break of the outer sheath is 342%, and the tensile strength of the outer sheath is 18.8 MPa.

[0067] Comparative Example 1 The difference between this comparative example and Example 1 is as follows: In this comparative example, sepiolite was used without modification, that is, sepiolite was used directly to replace modified sepiolite. The volume resistivity of the insulating layer is 5×10⁻⁶. 13 Ω·m, elongation at break 180%, tensile strength 5.2MPa; The other raw materials, steps and parameters are the same as in Example 1.

[0068] Comparative Example 2 The difference between this comparative example and Example 1 is as follows: In this comparative example, montmorillonite was used without modification, that is, montmorillonite was used directly to replace modified montmorillonite. The other raw materials, steps and parameters are the same as in Example 1.

[0069] The elongation at break of the outer sheath is 260%, and the tensile strength of the outer sheath is 14.3 MPa.

[0070] Comparative Example 3 The difference between this comparative example and Example 1 is as follows: The outer sheath layer of this comparative example does not contain nano boron nitride. Specifically, the outer sheath layer includes the following raw materials in parts by weight: 55 parts polyarylene ether nitrile, 35 parts TPU, 12 parts modified montmorillonite, 7 parts light stabilizer and 1.2 parts lubricant. The other raw materials, steps and parameters are the same as in Example 1.

[0071] The elongation at break of the outer sheath is 282%, and the tensile strength of the outer sheath is 10.5 MPa.

[0072] Test case The salt spray resistant island and reef cables prepared in the above embodiments and comparative examples were subjected to the following tests, and the test results are shown in Table 1. Salt spray resistance: Refer to GB / T 10125-2021; 1. Take a 1m long cable sample, remove the seals at both ends, and place it in a salt spray chamber; 2. Set a 10% NaCl solution, temperature 35℃, and spray continuously for 1000h; 3. After the test, observe the appearance (no cracking, corrosion, or delamination). Finally, test the insulation resistance retention rate (retention rate = resistance after test / initial resistance × 100%), requiring no abnormalities in appearance and an insulation resistance retention rate ≥ 85%; UV aging resistance: Following ASTM G154-2021, cable samples were subjected to UVA-340 lamp irradiation at an intensity of 0.89 W / (m²). 2 •nm), blackboard temperature 60℃, condensation cycle 4h (1h irradiation + 3h condensation); after 1500h, the tensile strength attenuation rate of the outer sheath layer is tested = (initial strength - strength after aging) / initial strength × 100%.

[0073] Table 1

[0074] It is important to note that in Comparative Example 1, the sepiolite without stearic acid coupling agent treatment has poor compatibility with EPDM rubber, and it is prone to agglomeration during the mixing process, resulting in pores and interface defects within the insulation layer. Salt spray can quickly penetrate through these defects, causing corrosion of the tin plating layer on the conductor surface and damaging the structural integrity of the insulation layer, leading to localized cracking and a significant decrease in volume resistivity. In Comparative Example 2, the unmodified montmorillonite has strong interlayer forces, making it difficult to disperse uniformly in the polyarylene ether nitrile-TPU system and unable to form an effective barrier network. Salt spray gradually penetrates into the outer sheath layer, reacting with the galvanized steel wire of the armor layer to generate corrosion products, causing localized bulging of the outer sheath layer; however, because the insulation layer is still a modified sepiolite composite system, it is not significantly affected. Comparative Example 3 did not contain nano-boron nitride. However, nano-boron nitride not only enhances the mechanical strength of the outer sheath layer, but also synergistically forms a dense barrier network with modified montmorillonite. Without nano-boron nitride, the structural density of the outer sheath layer decreases, and salt spray can easily penetrate the outer sheath layer to corrode the armor layer, while also causing delamination between the outer sheath layer and the armor layer. In addition, without the support of nano-boron nitride, the corrosion resistance and structural stability of the outer sheath layer are insufficient, resulting in large-area bulging, and salt spray indirectly affects the performance of the insulation layer.

[0075] Unless otherwise specified, all raw materials, reagents, instruments, and equipment used in this invention can be purchased commercially or prepared using existing methods. The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this invention. It should be understood that the above descriptions are merely specific embodiments of this invention and are not intended to limit the invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A salt spray resistant cable for islands and reefs, comprising, from the inside out: The conductor, insulation layer, sheath layer, armor layer and outer sheath layer are characterized in that the insulation layer comprises the following raw materials in parts by weight: 100 parts EPDM rubber, 12-25 parts modified sepiolite, 1-6 parts vulcanizing agent and 0.5-2 parts mildew inhibitor; The modified sepiolite is sepiolite treated with stearic acid coupling agent; The outer sheath layer comprises the following raw materials in parts by weight: 50-70 parts polyarylene ether nitrile, 30-50 parts TPU, 5-15 parts nano boron nitride, 8-16 parts modified montmorillonite, 4-12 parts light stabilizer and 0.3-2.5 parts lubricant; The modified montmorillonite is ammonium salt modified montmorillonite.

2. The salt spray resistant cable for islands and reefs as described in claim 1, characterized in that, The insulating layer comprises the following raw materials in parts by weight: 100 parts EPDM rubber, 15-20 parts modified sepiolite, 2-5 parts vulcanizing agent and 0.8-1.5 parts mildew inhibitor; And / or, the outer sheath layer comprises the following raw materials in parts by weight: 50-60 parts polyarylene ether nitrile, 30-40 parts TPU, 6-12 parts nano boron nitride, 10-15 parts modified montmorillonite, 5-10 parts light stabilizer and 0.5-2 parts lubricant.

3. The salt spray resistant cable for islands and reefs as described in claim 1, characterized in that, The modified montmorillonite is at least one of octadecyl dimethyl benzyl ammonium chloride modified montmorillonite, octadecyl dimethyl ammonium chloride modified montmorillonite, dioctadecyl dimethyl ammonium chloride modified montmorillonite, octadecyl-2-ethylhexyl dimethyl ammonium chloride modified montmorillonite, and octadecyl dihydroxyethyl methyl ammonium chloride modified montmorillonite. And / or, the vulcanization aid comprises 2.0 to 3.0 parts of peroxide vulcanizing agent and 1.0 to 2.0 parts of crosslinking accelerator; And / or, the antifungal agent is at least one of iodopropynyl butylcarbamate or 2-n-octyl-4-isothiazolin-3-one; And / or, the diameter of the nano-boron nitride is 1~50 nm; And / or, the light-stabilizing agent is 2-4 parts of benzotriazole derivative, 2-4 parts of ultraviolet absorber, and 1-2 parts of light stabilizer; And / or, the lubricant is selected from at least one of zinc stearate, calcium stearate, magnesium stearate, low molecular weight polyethylene wax, paraffin wax, and ethylene bis-stearamide.

4. The salt spray resistant cable for islands and reefs as described in claim 3, characterized in that, The peroxide sulfiding agent is at least one of dicumyl peroxide and bis(2,5-dimethyl-2,5-ditert-butylperoxide); And / or, the crosslinking accelerator is at least one of triallyl isocyanurate and trimethylolpropane triacrylate; And / or, the benzotriazole derivative is at least one of benzotriazole, methylbenzotriazole, and carboxybenzotriazole; And / or, the ultraviolet absorber is at least one of 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-hydroxy-4-n-octyloxybenzophenone, and 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole; And / or, the light stabilizer is at least one of bis(2,2,6,6-tetramethylpiperidinol) sebacate, poly[[6-[(1,1,3,3-tetramethylbutyl)amino]-1,3,5-triazine-2,4-diyl][(2,2,6,6-tetramethyl-4-piperidinyl)imino]-1,6-hexadiyl[(2,2,6,6-tetramethyl-4-piperidinyl)imino]], and bis(2,2,6,6-tetramethylpiperidinol) sebacate.

5. The salt spray resistant cable for islands and reefs as described in claim 1, characterized in that, The conductor is made of multiple strands of tin-plated copper wire, and water-blocking paste can be filled between the strands. And / or, the diameter of the tin-plated copper wire is 0.2~0.8mm; And / or, the pitch ratio of the strand is 14.5 to 15.5 times; And / or, the armor layer consists of two galvanized steel wire layers, namely an inner galvanized steel wire layer and an outer galvanized steel wire layer.

6. The salt spray resistant cable for islands and reefs as described in claim 5, characterized in that, The inner galvanized steel wire layer and the outer galvanized steel wire layer have opposite twisting directions; And / or, the twisting pitch ratio of the inner galvanized steel wire layer is 14 to 15 times, and the wire tension is 10 to 12 N; And / or, the twisting pitch ratio of the outer galvanized steel wire layer is 12 to 13 times, and the wire tension is 12 to 15 N.

7. The method for preparing the salt spray resistant island / reef cable according to any one of claims 1 to 6, characterized in that, Includes the following steps: S1. The raw materials for preparing the insulating layer are mixed, granulated, and then the insulating layer is extruded onto the surface of the conductor. After vulcanization, a preform is obtained. S2. Aluminum-plastic composite strip is longitudinally wrapped around the surface of the preform to form an aluminum-plastic composite strip longitudinal wrapping layer; then TPU is extruded onto the surface of the aluminum-plastic composite strip longitudinal wrapping layer to form a TPU inner sheath; the two together constitute the sheath layer. S3. Two layers of galvanized steel wire with opposite twisting directions are wrapped around the surface of the sheath layer to form an armor layer; S4. After mixing the raw materials for the outer sheath layer, extrude them onto the surface of the armor layer to obtain a salt spray resistant island and reef cable.

8. The method for preparing the salt fog resistant island / reef cable as described in claim 7, characterized in that, In S1, the mixing is carried out using an internal mixer at a temperature of 110~120℃, a pressure of 0.3~0.5MPa, and a rotation speed of 30~40r / min for 10~30min. Then, it is fed into a granulator and granulated at an extrusion temperature of 110~150℃ and a screw rotation speed of 25~35r / min to obtain insulating particles. And / or, in S1, the thickness of the extrusion is 1.5~2.0mm; And / or, in S1, the extruded material is cooled in water at 20~30℃ for 10~15 minutes; And / or, in S1, the vulcanization is carried out at 160~170°C for 15~20 min.

9. The method for preparing the salt spray resistant island / reef cable as described in claim 7, characterized in that, In S2, the vertical overlap rate is 15-20%; And / or, in S2, the extruded TPU is produced using an extruder with a barrel temperature of 170~180℃, a screw speed of 30~40r / min, and an extrusion thickness of 1.5~2.0mm. After extrusion, the TPU is cooled by cooling water at 20~30℃ for 10~15min to form a TPU inner sheath.

10. The method for preparing the salt fog resistant island / reef cable as described in claim 7, characterized in that, In S4, the mixing process is as follows: polyarylene ether nitrile is vacuum plasticized at 168~172℃ for 10~15min, and the moisture content after plasticization is controlled to be ≤0.1%; then the other raw materials for the preparation of the outer sheath layer are added to a twin-screw extruder and mixed for 15~20min at a barrel temperature of 190~195℃, a screw speed of 40~50r / min, and a feeding speed of 20~30kg / h to obtain outer sheath granules; And / or, in S4, the outer sheath particles are extruded onto the outside of the armor layer, with the extrusion thickness controlled at 2.5~3.5mm and the linear speed at 5~8m / min. After extrusion, the material is air-cooled at 20~30℃ for 10~15min.

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