Waterproof marine communication cable and preparation method thereof

Abstract

The invention provides a waterproof marine communication cable and a preparation method thereof, and belongs to the technical field of cable processing, the waterproof marine communication cable comprises a conductor and the following functional layers sequentially coating the conductor from inside to outside: a polyethylene composite insulating layer, a rubber composite waterproof layer, a modified filling layer, a compatible flame-retardant layer, a low-temperature toughening lining layer and a salt mist resistant outer sheath layer; the method comprises the following steps: respectively performing premixing and secondary blending granulation on raw materials of each functional layer, and then performing synchronous co-extrusion coating, vacuum filling compaction, hot-pressing compounding, layered coating, segmented cooling and performance testing, and screening to obtain a qualified cable. The marine communication cable effectively solves the problems of moisture invasion, interlayer stripping, structural deformation, low-temperature embrittlement, salt mist resistance, imbalance in flame retardance and the like of an existing marine communication cable, the comprehensive service performance and reliability of the cable are remarkably improved, and the marine communication cable adapts to the harsh use environment of a ship.

Description

Technical Field

[0001] This invention relates to the field of cable processing technology, and in particular to a waterproof marine communication cable and its preparation method. Background Technology

[0002] Marine communication cables are a crucial component of shipboard communication systems, used to transmit various signals and ensure the normal operation of navigation, maneuvering, and monitoring functions. In the complex environment of a ship, communication cables need to possess multiple properties such as waterproofing, salt spray resistance, low-temperature resistance, vibration resistance, and flame retardancy. However, existing marine communication cables still present some problems in practical use.

[0003] On the one hand, traditional marine communication cables lack sufficient waterproof reliability. Ships are constantly immersed in seawater and surrounded by salt spray. Ordinary insulation layers lack effective hydrophobic design, easily absorbing moisture and leading to a decline in insulation performance. Furthermore, the adhesion between the insulation layer and the water-blocking layer is weak, easily creating gaps under ship vibration, becoming channels for moisture intrusion and causing signal transmission failures. On the other hand, the sealing effect of existing water-blocking layers is difficult to maintain in the long term. Traditional water-blocking layers mostly rely on the elastic seal of single rubber without targeted adhesive additives, resulting in weak bonding with adjacent structural layers. After long-term use, they are prone to delamination and failure. Some water-blocking layers age rapidly, hardening and becoming brittle under long-term environmental influences, losing their sealing function.

[0004] Furthermore, existing filler layers are prone to absorbing water and swelling, leading to structural damage. Traditional filler materials are mostly ordinary water-absorbing resins or inorganic fillers, lacking hydrophobic modification and structural constraints. After absorbing water, their volume expands significantly, squeezing the wire core and surrounding functional layers, causing cable structural deformation, water-blocking layer rupture, and compromising the overall waterproof system. Moreover, existing flame-retardant layers suffer from an imbalance between hydrophobicity and compatibility. The hydrophilic fillers used in traditional flame-retardant layers easily absorb moisture from salt spray, reducing flame-retardant efficiency while accelerating moisture penetration; furthermore, the polarity of the raw materials in the flame-retardant layer differs greatly from that of adjacent layers, lacking compatibility design, making interlayer peeling easy and further exacerbating the risk of moisture intrusion.

[0005] Meanwhile, existing inner linings have poor low-temperature adaptability. Traditional inner lining materials focus on strength enhancement, but are prone to brittleness and cracking in the extreme low-temperature environments encountered by ships at sea, and the broken protective barrier cannot prevent the intrusion of external corrosive media. In addition, the existing outer sheath lacks sufficient salt spray resistance and functional synergy, and is prone to aging and cracking under long-term salt spray corrosion; moreover, the inorganic flame-retardant fillers are unevenly dispersed, causing flame-retardant performance and mechanical properties to mutually restrict each other, making it difficult to meet the requirements of long-term use. Summary of the Invention

[0006] In order to overcome the shortcomings of the prior art, the purpose of this invention is to provide a waterproof marine communication cable and its preparation method, which effectively solves the problems of water intrusion, interlayer peeling, structural deformation, low temperature brittleness, and imbalance between salt spray resistance and flame retardant performance in existing marine communication cables, significantly improving the overall service performance and reliability of the cable and making it suitable for the harsh operating environment of ships.

[0007] To achieve the above objectives, the present invention provides the following solution: On one hand, the present invention provides a waterproof marine communication cable, comprising a conductor, and the following functional layers sequentially wrapped around the conductor from the inside out: a polyethylene composite insulation layer, a rubber composite water-blocking layer, a modified filler layer, a compatibility flame-retardant layer, a low-temperature toughening inner liner layer, and a salt spray resistant outer sheath layer; wherein, the polyethylene composite insulation layer is made of raw materials including low-density polyethylene, ethylene-vinyl acetate copolymer, and hydrophobic modified nanofiller; the rubber composite water-blocking layer is made of raw materials including rubber, compatibilizer, and vulcanizing agent; the modified filler layer is made of raw materials including hydrophobic modified diatomaceous earth and water-absorbing resin; the compatibility flame-retardant layer is made of raw materials including resin matrix, hydrophobic modified flame-retardant filler, and halogen-free intumescent flame retardant; the low-temperature toughening inner liner layer is made of raw materials including rubber matrix and polyolefin elastomer; and the salt spray resistant outer sheath layer is made of raw materials including rubber, salt spray resistant modifier, and inorganic flame-retardant filler.

[0008] Preferably, the weight parts of each raw material in the polyethylene composite insulation layer are: 73-77 parts of low-density polyethylene, 13-15 parts of ethylene-vinyl acetate copolymer, 4.5-5.5 parts of hydrophobic modified nanofiller, 2.2-2.8 parts of compatibilizer, 0.35-0.45 parts of antioxidant, and 0.25-0.35 parts of ultraviolet absorber; The weight parts of each raw material in the rubber composite water-blocking layer are as follows: 66-69 parts butyl rubber, 16-19 parts compatibilizer, 3.5-4.5 parts talc, 3.2-3.8 parts tackifier, 1.3-1.4 parts sulfur, and 0.6-0.7 parts antioxidant.

[0009] Preferably, the weight parts of each raw material in the modified filler layer are: 62-68 parts of hydrophobic modified diatomaceous earth, 21-24 parts of polypropylene fiber, 6-7 parts of fumed silica, and 3.5-4.5 parts of water-absorbing resin. The weight proportions of each raw material in the compatibility flame retardant layer are as follows: 46-49 parts phenolic resin, 26-29 parts hydrophobically modified flame retardant filler, 36-39 parts high-density polyethylene, 3.2-3.8 parts melamine cyanurate, 4.5-5.5 parts compatibilizer, 13-14 parts halogen-free intumescent flame retardant, 6.5-7.5 parts antimony trioxide, 2.2-2.8 parts zinc borate, and 5.2-5.8 parts Ca / Zn composite stabilizer.

[0010] Preferably, the weight proportions of each raw material in the low-temperature toughened liner are: 41-44 parts of nitrile rubber, 26-29 parts of polyolefin elastomer, 16-19 parts of light calcium carbonate, 5.5-6.5 parts of talc, 2.2-2.8 parts of antioxidant, 3.2-3.8 parts of plasticizer, and 4.2-4.8 parts of stabilizer; The weight proportions of each raw material in the salt spray resistant outer sheath layer are as follows: 23-24 parts styrene-butadiene rubber, 19.5-23.5 parts salt spray resistant modifier, 41-44 parts low-density polyethylene, 17-19 parts nylon, 18.5-19.5 parts magnesium hydroxide, 26-29 parts aluminum hydroxide, 1.2-1.8 parts filler dispersant, 2.2-2.8 parts antioxidant, and 8.5-9.5 parts vulcanizing agent.

[0011] Preferably, the hydrophobic modified nanofiller is stearic acid modified nano-silica with a particle size range of 100-200 nm; the hydrophobic modified flame retardant filler in the compatible flame retardant layer is stearic acid modified magnesium hydroxide with a particle size range of 5-10 μm.

[0012] Preferably, the compatibilizer in the rubber composite water-blocking layer is chlorinated polyethylene, and the tackifier is polyisobutylene; the salt spray resistant modifier in the salt spray resistant outer sheath layer is a mixture of chlorosulfonated polyethylene and zinc powder in a weight ratio of 4-5:1.

[0013] On the other hand, the present invention also provides a method for preparing the above-mentioned waterproof marine communication cable, comprising the following steps: S1. The raw materials of each functional layer are premixed and secondary blended and then granulated to obtain raw material particles of each layer. Then, the raw material particles of polyethylene composite insulation layer and rubber composite water-blocking layer are simultaneously co-extruded and coated on the outside of the conductor to form the wire core. S2. Inject the raw material particles of the modified filling layer into the gap of the wire core and compact them. Then, wrap the raw material particles of the compatible flame retardant layer on the outside and perform hot pressing composite. After that, co-extrude the raw material particles of the low temperature toughening inner lining layer and the salt spray resistant outer sheath layer on the outside of the compatible flame retardant layer to form the cable intermediate. S3. The intermediate body of the cable is cooled in sections, and then water pressure test and low temperature aging pretreatment are carried out in sequence to obtain waterproof marine communication cable.

[0014] Preferably, in S1, the premixing process parameters are: temperature 165-175℃, rotation speed 260-290rpm, and time 15-20min; the secondary blending process parameters are: temperature 170-180℃, rotation speed 280-300rpm, and time 20-25min; the particle size of the raw material particles after granulation is 2-3mm; and the simultaneous co-extrusion coating process parameters are: temperature 175-185℃, die pressure 16-17MPa, and extrusion speed 8-10m / min.

[0015] Preferably, in step S2, the raw material particles are injected using a vacuum filling method, with the vacuum degree controlled at -0.065 to -0.075 MPa; the compaction pressure is 6-7 MPa, and the compacted filling density is ≥1.2 g / cm³. 3 The hot-pressing composite process parameters are: temperature 145-155℃, pressure 8.5-9.5MPa, and hot-pressing time 35-50 seconds; the co-extrusion temperature of the low-temperature toughened inner liner is 165-175℃, the co-extrusion temperature of the salt spray resistant outer sheath is 180-190℃, and the die pressure of both co-extrusions is 15-17MPa.

[0016] Preferably, in S3, the segmented cooling includes sequential water cooling and air cooling, wherein the water cooling temperature is 22-28℃ and the cooling time is 3-5 min, and the air cooling is room temperature cooling and the cooling time is 5-8 min; the process parameters for the water pressure test are: pressure 1.2 MPa, pressure holding time 2 hours, and leakage ≤0.01 mL / min; the process parameters for the low temperature aging pretreatment are: temperature -30℃, time 48 hours, and the screening criteria are no interlayer delamination, no cracks, and no deformation.

[0017] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects: This invention effectively solves the problems of insufficient waterproof reliability and easy water intrusion in traditional marine communication cables through the synergistic protection of a polyethylene composite insulation layer, a rubber composite water-blocking layer, and a modified filler layer. The polyethylene composite insulation layer uses low-density polyethylene and ethylene-vinyl acetate copolymer as the base material, combining excellent insulation and flexibility. The hydrophobic modified nanofiller blocks the water adsorption path, preventing insulation performance degradation due to moisture absorption. The rubber composite water-blocking layer, mainly composed of butyl rubber, forms a dense molecular structure under the action of a vulcanizing agent. Combined with a compatibilizer, it strengthens the interfacial bonding with adjacent layers, preventing gaps under vibration. The modified filler layer uses a combination of hydrophobic modified diatomaceous earth and water-absorbing resin. The water-absorbing resin locks in trace amounts of internal moisture, while the hydrophobic modified diatomaceous earth blocks external water intrusion. Simultaneously, polypropylene fibers constrain water absorption and expansion, preventing structural deformation. This forms a triple protection of insulation and hydrophobicity, sealing and water blocking, and filling and water locking, overcoming the contradiction of easy failure in traditional single waterproof structures and ensuring long-term waterproofing of the cable in seawater immersion and salt spray environments.

[0018] (2) This invention relies on the complementary functions of the compatible flame-retardant layer, the low-temperature toughening inner lining layer and the salt spray resistant outer sheath layer to effectively solve the problems of poor adaptability to extreme environments and difficulty in achieving both flame retardancy and weather resistance in traditional marine communication cables. The compatibility flame-retardant layer uses phenolic resin and high-density polyethylene as a composite matrix, which uniformly disperses the hydrophobic modified flame-retardant filler and halogen-free intumescent flame retardant. This achieves high-efficiency flame retardancy while avoiding the performance degradation caused by moisture absorption of traditional hydrophilic fillers. The compatibility agent also optimizes the bonding with adjacent layers. The low-temperature toughening inner lining layer blends nitrile rubber and polyolefin elastomer. The branched structure of the polyolefin elastomer enhances low-temperature toughness, allowing the material to maintain good mechanical properties and prevent brittleness even at extreme low temperatures of -30℃. The salt spray resistant outer sheath layer uses styrene-butadiene rubber and low-density polyethylene as the base material, with the addition of a salt spray resistant modifier composed of chlorosulfonated polyethylene and zinc powder to resist salt spray corrosion and seawater erosion. Combined with a silane coupling agent to improve the dispersion of inorganic flame-retardant fillers, it balances flame retardancy and aging resistance, thus giving the cable comprehensive capabilities of flame retardancy, safety, low-temperature resistance, and salt spray resistance. This breaks the contradiction that optimizing a single performance of traditional cables may sacrifice other performances, making it suitable for the complex and harsh environment of ships.

[0019] (3) This invention effectively solves the problems of weak interlayer bonding and insufficient structural density caused by traditional preparation processes through the synergistic process of premixing and secondary blending, synchronous co-extrusion coating, vacuum filling and compaction, and hot-pressing composite. In the premixing stage, the base material of each functional layer is fused with the compatibilizer in advance, and the remaining components are added in the secondary blending to ensure uniform dispersion of raw materials and avoid local performance defects; the synchronous co-extrusion coating technology realizes the integrated molding of polyethylene composite insulation layer and rubber composite water-blocking layer, low-temperature toughening inner lining layer and salt spray resistant outer sheath layer, promotes the mutual penetration of interlayer molecular chains, significantly improves bonding strength, and prevents delamination under long-term vibration; the vacuum filling and compaction process injects modified filler layer raw materials and compacts them in a vacuum environment of -0.065~-0.075MPa to eliminate internal voids; the hot-pressing composite process allows the compatible flame retardant layer to be tightly bonded to the adjacent layers, optimizing the overall structural stability. Thus, the preparation method of this invention solves the problem of interlayer gaps and loose structure that are easily generated by traditional segmented preparation, and finally forms a waterproof marine communication cable with a tight structure and synergistic performance, which greatly improves the overall service reliability and service life. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a flowchart of a method for preparing a waterproof marine communication cable according to the present invention. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] like Figure 1 As shown, the present invention provides a method for preparing a waterproof marine communication cable, comprising the following steps: S1. The raw materials of each functional layer are premixed and then granulated to obtain raw material particles of each layer. Subsequently, the raw material particles of polyethylene composite insulation layer and rubber composite water-blocking layer are co-extruded and coated on the outside of the conductor to form the wire core.

[0025] Specifically, the premixing process parameters are: temperature 165-175℃, rotation speed 260-290rpm, and time 15-20min. First, the base material and compatibilizer are fully melted and mixed at this temperature and rotation speed, allowing the compatibilizer molecular chains to be uniformly dispersed in the base material. This pre-constructs the base material-compatible interface system to avoid the agglomeration of compatibilizer and filler, which could lead to local performance defects.

[0026] The process parameters for secondary blending are: temperature 170-180℃, rotation speed 280-300rpm, and time 20-25min. By increasing the temperature and rotation speed based on the premixed system, the shear force of the materials is enhanced, allowing the inorganic fillers and functional additives to fully embed into the gaps between the matrix and compatibilizer system. Simultaneously, high temperatures prevent raw material degradation, ensuring that all components work synergistically.

[0027] After granulation, the particle size of the raw material is 2-3 mm. The process parameters for simultaneous co-extrusion coating are: temperature 175-185℃, die pressure 16-17MPa, and extrusion speed 8-10m / min. This temperature ensures that both the polyethylene composite insulation layer and the rubber composite water-blocking layer raw materials are in their optimal molten state. The die pressure ensures that the two molten materials are tightly bonded and that the molecular chains interpenetrate. The extrusion speed is matched with the material flowability to avoid air residue between layers, thereby improving the interlayer bonding strength from the source.

[0028] S2. Inject the raw material particles of the modified filling layer into the gap of the wire core and compact them. Then, wrap the raw material particles of the compatible flame retardant layer on the outside and perform hot pressing composite. After that, co-extrude the raw material particles of the low temperature toughening inner lining layer and the salt spray resistant outer sheath layer on the outside of the compatible flame retardant layer to form the cable intermediate.

[0029] Specifically, the raw material particles are injected using a vacuum filling method, with the vacuum level controlled at -0.065 to -0.075 MPa. The negative pressure environment can expel air from the gaps between the wire cores, preventing residual air from forming moisture adsorption channels. At the same time, it allows the modified filler material to fully fill the tiny gaps under the action of pressure difference, ensuring that there are no dead corners in the filling.

[0030] The compaction pressure is 6-7 MPa, and the compacted filling density is ≥1.2 g / cm³. 3 By appropriately compacting the filling particles to create a tight packing, combined with the three-dimensional network constraint of polypropylene fibers, the subsequent water absorption and expansion of the water-absorbing resin is suppressed, thus avoiding the squeezing of the core.

[0031] The process parameters for hot-pressing composite are: temperature 145-155℃, pressure 8.5-9.5MPa, and hot-pressing time 35-50 seconds. High temperature promotes the diffusion and fusion of molecular chains between the compatible flame-retardant layer and the adjacent layer, high pressure eliminates micro gaps between layers, and hot-pressing time ensures that the interface bonding reaches a stable state, thereby improving the interlayer peel strength.

[0032] The co-extrusion temperature for the low-temperature toughened inner liner is 165-175℃, and the co-extrusion temperature for the salt spray resistant outer sheath is 180-190℃. The die pressure for both co-extrusions is 15-17MPa. The purpose is to match the melting characteristics of the two materials to avoid uneven coating due to different melting temperatures. The die pressure ensures a tight bond between the inner liner and the outer sheath, and between the inner liner and the flame-retardant layer, forming a continuous protective structure.

[0033] S3. The intermediate body of the cable is cooled in sections, and then water pressure test and low temperature aging pretreatment are carried out in sequence to obtain waterproof marine communication cable.

[0034] Specifically, the segmented cooling includes sequential water cooling and air cooling. The water cooling temperature is 22-28℃ and the cooling time is 3-5 minutes, while the air cooling is room temperature cooling and the cooling time is 5-8 minutes. First, water cooling is used to quickly reduce the surface temperature of the cable to achieve preliminary shaping, and then air cooling is used to slowly release internal stress, so as to avoid cracks or interlayer separation caused by sudden cooling and ensure structural stability.

[0035] The hydrostatic test parameters are: pressure 1.2 MPa, pressure holding time 2 hours, and leakage ≤0.01 mL / min. The principle of this test is to simulate the pressure environment of seawater to verify the sealing integrity of the cable, and to ensure no moisture penetration channels by controlling the leakage rate. The low-temperature aging pretreatment parameters are: temperature -30℃, time 48 hours, and the screening criteria are no interlayer delamination, no cracks, and no deformation. Its principle is to simulate the extreme low-temperature environment of a ship in the open ocean, accelerating the degradation of material properties, and screening out products that can maintain structural and performance stability at low temperatures, avoiding low-temperature brittle fracture failure in actual use.

[0036] The waterproof marine communication cable prepared according to the above preparation method includes a conductor and the following functional layers wrapped on the conductor from the inside out: a polyethylene composite insulation layer, a rubber composite water-blocking layer, a modified filler layer, a compatible flame-retardant layer, a low-temperature toughening inner lining layer, and a salt spray resistant outer sheath layer.

[0037] The polyethylene composite insulation layer is made from raw materials including low-density polyethylene, ethylene-vinyl acetate copolymer, and hydrophobically modified nanofillers. Low-density polyethylene provides excellent insulation and processing fluidity, while ethylene-vinyl acetate copolymer enhances the material's flexibility and water resistance through polar groups. The hydrophobically modified nanofillers (stearic acid modified nano silica, particle size 100-200nm) reduce moisture absorption by covering the hydrophilic groups on the filler surface with hydrophobic segments of stearic acid. At the same time, the nanoparticle size fills the gaps in the substrate, further improving the synergistic performance of insulation and water resistance.

[0038] The rubber composite water-blocking layer is made of raw materials including rubber, compatibilizer, and vulcanizing agent. Butyl rubber has dense molecular chains and low air permeability, serving as the core of water blocking. The vulcanizing agent sulfur cross-links the rubber molecules to form a dense network, enhancing sealing stability. The compatibilizer chlorinated polyethylene adjusts the polarity difference between butyl rubber and adjacent layer materials, improving interfacial compatibility. The tackifier polyisobutylene enhances the material's adhesion through molecular chain entanglement, ensuring that the water-blocking layer is tightly bonded to adjacent layers and blocking the path of water penetration.

[0039] The modified filler layer is made from raw materials including hydrophobically modified diatomaceous earth and water-absorbing resin. The hydrophobically modified diatomaceous earth (modified with cetyltrimethylammonium bromide) forms a hydrophobic film on the surface of the diatomaceous earth through cationic surfactants, which reduces water adsorption. At the same time, the porous structure can adsorb trace amounts of water. The water-absorbing resin actively captures the intruding water. Polypropylene fibers form a three-dimensional network structure, which constrains the expansion space of the water-absorbing resin. Fumed silica enhances the structural stability of the filler layer through nanoparticle aggregation, preventing the filler layer from collapsing.

[0040] The compatible flame retardant layer is made from raw materials including a resin matrix, hydrophobically modified flame retardant fillers, and halogen-free intumescent flame retardants. Phenolic resin and high-density polyethylene form a composite matrix that balances rigidity and processability. The hydrophobically modified flame retardant fillers (stearic acid modified magnesium hydroxide, particle size 5-10μm) reduce moisture absorption through hydrophobic modification and decompose to absorb heat and cool down during combustion. The halogen-free intumescent flame retardant forms an expanded char layer during combustion, which blocks oxygen and heat. Melamine cyanurate, antimony trioxide, and zinc borate synergistically improve the flame retardant efficiency. The compatibilizer ethylene-acrylate copolymer improves the dispersibility of different polar substrates and fillers, avoiding an imbalance between flame retardant performance and compatibility.

[0041] The low-temperature toughened inner liner is made of raw materials including a rubber matrix and a polyolefin elastomer. Nitrile rubber provides basic mechanical strength, while the branched structure of the polyolefin elastomer can maintain the flexibility of the molecular chain at low temperatures, alleviating the problem of low-temperature embrittlement of nitrile rubber. Light calcium carbonate and talc are used as rigid fillers to balance toughening and structural strength, avoiding excessive toughening that would reduce the protective ability of the inner liner.

[0042] The salt spray resistant outer sheath is made from raw materials including rubber, salt spray resistant modifier, and inorganic flame retardant filler. Styrene-butadiene rubber provides excellent mechanical properties and ductility. In the salt spray resistant modifier (chlorosulfonated polyethylene and zinc powder mixed at a weight ratio of 4-5:1), the chlorosulfonyl groups of chlorosulfonated polyethylene enhance weather resistance and salt spray resistance. Zinc powder acts as a sacrificial anode, preferentially corroding and protecting the substrate from salt spray erosion. The inorganic flame retardant filler (magnesium hydroxide, aluminum hydroxide) undergoes endothermic combustion decomposition. Combined with the filler dispersant silane coupling agent KH-550, it improves filler dispersibility, prevents filler agglomeration that could lead to cracking of the outer sheath, and balances salt spray resistance, flame retardancy, and aging resistance.

[0043] Furthermore, in the above-mentioned content, the weight parts of each raw material in the polyethylene composite insulation layer are as follows: 73-77 parts of low-density polyethylene, 13-15 parts of ethylene-vinyl acetate copolymer, 4.5-5.5 parts of hydrophobic modified nanofiller, 2.2-2.8 parts of compatibilizer, 0.35-0.45 parts of antioxidant, and 0.25-0.35 parts of ultraviolet absorber. This ratio ensures that the base material dominates, guaranteeing insulation and processing performance. The ratio of hydrophobic modified nanofiller to compatibilizer is matched, which not only gives full play to the hydrophobic and compatibility effects, but also does not affect the performance of the base material itself. The addition of antioxidant and ultraviolet absorber can effectively inhibit material aging and extend service life.

[0044] The weight proportions of each raw material in the rubber composite water-blocking layer are as follows: 66-69 parts butyl rubber, 16-19 parts compatibilizer, 3.5-4.5 parts talc, 3.2-3.8 parts tackifier, 1.3-1.4 parts sulfur, and 0.6-0.7 parts antioxidant. This formulation uses butyl rubber as the main component to ensure the core water-blocking performance; the compatibilizer and tackifier are appropriately proportioned to ensure a balance between interlayer adhesion and self-adhesion; talc optimizes processing fluidity; the amount of sulfur controls the degree of cross-linking to avoid excessive cross-linking leading to rubber embrittlement; and the antioxidant delays material aging.

[0045] The weight proportions of each raw material in the modified filler layer are as follows: 62-68 parts of hydrophobic modified diatomaceous earth, 21-24 parts of polypropylene fiber, 6-7 parts of fumed silica, and 3.5-4.5 parts of water-absorbing resin. This ratio uses hydrophobic modified diatomaceous earth as the main filler material, the amount of polypropylene fiber ensures the formation of an effective three-dimensional network, fumed silica enhances the stability of the system, and the amount of water-absorbing resin can fully absorb water without causing excessive expansion due to excess.

[0046] The weight proportions of each raw material in the compatibility flame-retardant layer are as follows: 46-49 parts phenolic resin, 26-29 parts hydrophobically modified flame-retardant filler, 36-39 parts high-density polyethylene, 3.2-3.8 parts melamine cyanurate, 4.5-5.5 parts compatibilizer, 13-14 parts halogen-free intumescent flame retardant, 6.5-7.5 parts antimony trioxide, 2.2-2.8 parts zinc borate, and 5.2-5.8 parts Ca / Zn composite stabilizer. This formulation ensures a proper match between the composite matrix and the flame-retardant filler, balancing flame-retardant efficiency with the material's mechanical properties. The compatibilizer ensures uniform dispersion of all components, and the stabilizer inhibits material degradation during processing.

[0047] The weight proportions of each raw material in the low-temperature toughened inner liner are as follows: 41-44 parts nitrile rubber, 26-29 parts polyolefin elastomer, 16-19 parts light calcium carbonate, 5.5-6.5 parts talc, 2.2-2.8 parts antioxidant, 3.2-3.8 parts plasticizer, and 4.2-4.8 parts stabilizer. This ratio optimizes the low-temperature toughness and strength by adjusting the ratio of nitrile rubber to polyolefin elastomer, balances the performance of rigid fillers, improves processability with plasticizer, and extends service life with antioxidant and stabilizer.

[0048] The weight proportions of each raw material in the salt spray resistant outer sheath layer are as follows: 23-24 parts styrene-butadiene rubber, 19.5-23.5 parts salt spray resistant modifier, 41-44 parts low-density polyethylene, 17-19 parts nylon, 18.5-19.5 parts magnesium hydroxide, 26-29 parts aluminum hydroxide, 1.2-1.8 parts filler dispersant, 2.2-2.8 parts antioxidant, and 8.5-9.5 parts vulcanizing agent. This formulation ensures the mechanical properties of the composite substrate, guarantees corrosion resistance with the amount of salt spray resistant modifier, matches the flame retardant requirements with the proportion of flame retardant filler, ensures uniform dispersion of the filler with the dispersant, controls the degree of crosslinking with the vulcanizing agent, and delays aging with the antioxidant.

[0049] The above content will be further explained below through specific implementation methods. The described embodiments are only some embodiments of the present invention.

[0050] Example 1 In this embodiment, a waterproof marine communication cable is prepared, and the raw materials for each functional layer are proportioned by weight as follows: Polyethylene composite insulation layer: 75 parts low-density polyethylene, 14 parts ethylene-vinyl acetate copolymer, 5 parts stearic acid modified nano silica (particle size 150nm), 2.5 parts maleic anhydride grafted polyethylene, 0.4 parts antioxidant 1010, and 0.3 parts ultraviolet absorber UV-326. Rubber composite water-blocking layer: 67.5 parts butyl rubber, 17.5 parts chlorinated polyethylene, 4 parts talc, 3.5 parts polyisobutylene, 1.35 parts sulfur, and 0.65 parts antioxidant MB; Modified filler layer: 65 parts of hexadecyltrimethylammonium bromide modified diatomaceous earth (hydrophobicity 92%), 22.5 parts of polypropylene fiber (length 4mm), 6.5 parts of fumed silica, and 4 parts of water-absorbing resin; Compatible flame retardant layer: 47.5 parts phenolic resin, 27.5 parts stearic acid modified magnesium hydroxide (particle size 8μm), 37.5 parts high-density polyethylene, 3.5 parts melamine cyanurate, 5 parts ethylene-acrylate copolymer, 13.5 parts halogen-free intumescent flame retardant, 7 parts antimony trioxide, 2.5 parts zinc borate, and 5.5 parts Ca / Zn composite stabilizer; Low-temperature toughened inner lining: 42.5 parts nitrile rubber, 27.5 parts polyolefin elastomer, 17.5 parts light calcium carbonate, 6 parts talc, 2.5 parts antioxidant MB, 3.5 parts epoxidized soybean oil, and 4.5 parts stabilizer; Salt spray resistant outer sheath layer: 23.5 parts styrene-butadiene rubber, 21.5 parts salt spray resistant modifier (chlorosulfonated polyethylene and zinc powder weight ratio 4.5:1), 42.5 parts low density polyethylene, 18 parts nylon, 19 parts magnesium hydroxide, 27.5 parts aluminum hydroxide, 1.5 parts silane coupling agent KH-550, 2.5 parts antioxidant 1010, and 9 parts dicumyl peroxide.

[0051] The cable manufacturing steps are as follows: The raw materials for each functional layer were premixed and then granulated after secondary blending. The premixing process parameters were 170℃, 275rpm, and 18min, in which the base substrates of each layer were melt-mixed with the compatibilizer. The secondary blending process parameters were 175℃, 290rpm, and 22min, in which inorganic fillers and functional additives were added to the premixed system. After blending, the raw material particles with a particle size of 2.5mm were obtained. Subsequently, the raw material particles of the polyethylene composite insulation layer and the rubber composite water-blocking layer were simultaneously co-extruded and coated onto the outside of the conductor. The conductor was made of 35 strands of oxygen-free copper wire with a diameter of 0.175mm, which were annealed at 365℃ for 1.25h and had an elongation of 32%. The co-extrusion process parameters were 180℃, die pressure of 16.5MPa, and extrusion speed of 9m / min to form the wire core.

[0052] Modified filler particles are injected into the gaps between the wire cores using a vacuum filling method, with the vacuum level controlled at -0.07 MPa. After injection, the filler is compacted under a pressure of 6.5 MPa to ensure a filling density ≥1.2 g / cm³. 3 The raw material particles of the compatible flame retardant layer are coated on the outside of the filler layer and then hot-pressed together. The process parameters are: temperature 150℃, pressure 9MPa, and hot-pressing time 40 seconds. Then, the raw material particles of the low-temperature toughening inner lining layer and the salt spray resistant outer sheath layer are co-extruded and coated on the outside of the compatible flame retardant layer. The co-extrusion temperature of the inner lining layer is 170℃ and the co-extrusion temperature of the outer sheath layer is 185℃. The die pressure is 16MPa for both layers, forming the cable intermediate.

[0053] The cable intermediate body is cooled in sections, first by water cooling at 25℃ for 4 minutes, and then by air cooling at room temperature for 6 minutes. After cooling, it is subjected to water pressure test and low temperature aging pretreatment in sequence: water pressure test pressure is 1.2MPa, pressure holding for 2 hours, and leakage is ≤0.01mL / min; low temperature aging pretreatment temperature is -30℃ and time is 48 hours. Finished products without interlayer peeling, cracks and deformation are selected to obtain waterproof marine communication cables.

[0054] Example 2 In this embodiment, a waterproof marine communication cable is prepared, and the raw materials for each functional layer are proportioned by weight as follows: Polyethylene composite insulation layer: 73 parts low-density polyethylene, 13 parts ethylene-vinyl acetate copolymer, 4.5 parts stearic acid modified nano silica (particle size 100nm), 2.2 parts maleic anhydride grafted polyethylene, 0.35 parts antioxidant 1010, and 0.25 parts ultraviolet absorber UV-326; Rubber composite water-blocking layer: 66 parts butyl rubber, 16 parts chlorinated polyethylene, 3.5 parts talc, 3.2 parts polyisobutylene, 1.3 parts sulfur, and 0.6 parts antioxidant MB; Modified filler layer: 62 parts of hexadecyltrimethylammonium bromide modified diatomaceous earth (90% hydrophobicity), 21 parts of polypropylene fiber (3mm length), 6 parts of fumed silica, and 3.5 parts of water-absorbing resin; Compatible flame retardant layer: 46 parts phenolic resin, 26 parts stearic acid modified magnesium hydroxide (particle size 5μm), 36 parts high-density polyethylene, 3.2 parts melamine cyanurate, 4.5 parts ethylene-acrylate copolymer, 13 parts halogen-free intumescent flame retardant, 6.5 parts antimony trioxide, 2.2 parts zinc borate, and 5.2 parts Ca / Zn composite stabilizer; Low-temperature toughened inner lining: 41 parts nitrile rubber, 26 parts polyolefin elastomer, 16 parts light calcium carbonate, 5.5 parts talc, 2.2 parts antioxidant MB, 3.2 parts epoxidized soybean oil, and 4.2 parts stabilizer; Salt spray resistant outer sheath layer: 23 parts styrene-butadiene rubber, 19.5 parts salt spray resistant modifier (chlorosulfonated polyethylene and zinc powder weight ratio 4:1), 41 parts low-density polyethylene, 17 parts nylon, 18.5 parts magnesium hydroxide, 26 parts aluminum hydroxide, 1.2 parts silane coupling agent KH-550, 2.2 parts antioxidant 1010, and 8.5 parts dicumyl peroxide.

[0055] The cable manufacturing steps in this embodiment are the same as in Embodiment 1, only the process parameters are adjusted as follows: The premixing temperature was 165℃, the rotation speed was 260 rpm, and the time was 15 min; the secondary blending temperature was 170℃, the rotation speed was 280 rpm, and the time was 20 min; the particle size after granulation was 2 mm; the synchronous co-extrusion temperature was 175℃, the die pressure was 16 MPa, and the extrusion speed was 8 m / min; the conductor was 32 strands of oxygen-free copper wire with a diameter of 0.16 mm, which was annealed at 360℃ for 1.1 h and had an elongation of 30%.

[0056] Vacuum filling vacuum degree -0.065MPa; compaction pressure 6MPa; hot pressing composite temperature 145℃, pressure 8.5MPa, hot pressing time 35 seconds; inner liner co-extrusion temperature 165℃, outer sheath co-extrusion temperature 180℃, die head pressure 15MPa.

[0057] Water cooling temperature 22℃, time 3min; air cooling time 5min; water pressure test leakage ≤0.01mL / min; low temperature aging screening criteria are the same as in Example 1.

[0058] Example 3 In this embodiment, a waterproof marine communication cable is prepared, and the raw materials for each functional layer are proportioned by weight as follows: Polyethylene composite insulation layer: 77 parts low-density polyethylene, 15 parts ethylene-vinyl acetate copolymer, 5.5 parts stearic acid modified nano silica (particle size 200nm), 2.8 parts maleic anhydride grafted polyethylene, 0.45 parts antioxidant 1010, and 0.35 parts ultraviolet absorber UV-326; Rubber composite water-blocking layer: 69 parts butyl rubber, 19 parts chlorinated polyethylene, 4.5 parts talc, 3.8 parts polyisobutylene, 1.4 parts sulfur, and 0.7 parts antioxidant MB; Modified filler layer: 68 parts of hexadecyltrimethylammonium bromide modified diatomaceous earth (95% hydrophobicity), 24 parts of polypropylene fiber (5mm length), 7 parts of fumed silica, and 4.5 parts of water-absorbing resin. Compatible flame retardant layer: 49 parts phenolic resin, 29 parts stearic acid modified magnesium hydroxide (particle size 10μm), 39 parts high-density polyethylene, 3.8 parts melamine cyanurate, 5.5 parts ethylene-acrylate copolymer, 14 parts halogen-free intumescent flame retardant, 7.5 parts antimony trioxide, 2.8 parts zinc borate, and 5.8 parts Ca / Zn composite stabilizer; Low-temperature toughened inner lining: 44 parts nitrile rubber, 29 parts polyolefin elastomer, 19 parts light calcium carbonate, 6.5 parts talc, 2.8 parts antioxidant MB, 3.8 parts epoxidized soybean oil, and 4.8 parts stabilizer; Salt spray resistant outer sheath layer: 24 parts styrene-butadiene rubber, 23.5 parts salt spray resistant modifier (chlorosulfonated polyethylene and zinc powder weight ratio 5:1), 44 parts low-density polyethylene, 19 parts nylon, 19.5 parts magnesium hydroxide, 29 parts aluminum hydroxide, 1.8 parts silane coupling agent KH-550, 2.8 parts antioxidant 1010, and 9.5 parts dicumyl peroxide.

[0059] The cable manufacturing steps in this embodiment are the same as in Embodiment 1, only the process parameters are adjusted as follows: The premixing temperature was 175℃, the rotation speed was 290 rpm, and the time was 20 min; the secondary blending temperature was 180℃, the rotation speed was 300 rpm, and the time was 25 min; the particle size after granulation was 3 mm; the synchronous co-extrusion temperature was 185℃, the die pressure was 17 MPa, and the extrusion speed was 10 m / min; the conductor was 38 strands of oxygen-free copper wire with a diameter of 0.19 mm, which was annealed at 370℃ for 1.4 h and had an elongation of 33%.

[0060] Vacuum filling vacuum degree -0.075MPa; compaction pressure 7MPa; hot pressing composite temperature 155℃, pressure 9.5MPa, hot pressing time 50 seconds; inner liner co-extrusion temperature 175℃, outer sheath co-extrusion temperature 190℃, die head pressure 17MPa.

[0061] Water cooling temperature 28℃, time 5min; air cooling time 8min; water pressure test leakage ≤0.008mL / min; low temperature aging screening criteria are the same as in Example 1.

[0062] Comparative Example 1 The only difference between this comparative example and Example 1 is that the stearic acid-modified nano-silica in the polyethylene composite insulation layer is replaced with ordinary nano-silica (unmodified), the stearic acid-modified magnesium hydroxide in the compatible flame retardant layer is replaced with ordinary magnesium hydroxide (unmodified), and the cetyltrimethylammonium bromide-modified diatomaceous earth in the modified filler layer is replaced with ordinary diatomaceous earth (unmodified); the remaining raw material ratios, preparation steps, and process parameters are the same as in Example 1.

[0063] Comparative Example 2 The only difference between this comparative example and Example 1 is that the raw materials for each functional layer are not distinguished between premixing and secondary blending, but are used in a one-time blending process, that is, all raw materials of each layer are directly put into the mixing equipment and mixed at 175°C and 290 rpm for 30 minutes before granulation; the other raw material ratios, preparation steps and process parameters are the same as those in Example 1.

[0064] Comparative Example 3 The only difference between this comparative example and Example 1 is that maleic anhydride-grafted polyethylene is removed from the polyethylene composite insulation layer, ethylene-acrylate copolymer is removed from the compatibility flame retardant layer, and chlorinated polyethylene is removed from the rubber composite water-blocking layer; the remaining raw material ratios, preparation steps, and process parameters are the same as in Example 1.

[0065] Comparative Example 4 The only difference between this comparative example and Example 1 is the preparation process: the modified filler layer is filled under normal pressure (without vacuum environment) and is not compacted after filling; the compatible flame retardant layer is not hot-pressed after coating and is directly cooled; the segmented cooling is changed to single water cooling (25°C, 8 min) and there is no subsequent air cooling step; the remaining raw material ratios, functional layer structures and other process parameters are the same as those in Example 1.

[0066] The waterproof marine communication cables prepared in Examples 1-3 and Comparative Examples 1-4 were subjected to performance tests in accordance with relevant cable standards (GB / T 12706.1-2022, GB / T 10125-2021, GB / T 2408-2021). The test results are shown in Table 1.

[0067] Table 1 Cable performance test results

[0068] Table 1 shows that the waterproof marine communication cables prepared in Examples 1-3 exhibit excellent and stable core performance, with a water absorption rate of only 0.015%~0.018%, an interlayer peel strength of 2.8~3.1 N / mm, and a low-temperature impact strength of 11.0~12.5 kJ / m at -30℃. 2 The filler's water absorption and swelling rate is ≤4.0%. Furthermore, after 5000 hours of salt spray testing, there was no cracking or peeling, and the flame retardant rating reached UL94 V-0. The water pressure test leakage was ≤0.01mL / min, fully meeting the requirements of the harsh marine environment. In contrast, the performance of the four comparative examples was significantly inferior. Comparative Example 1 had a water absorption rate as high as 0.088%, the flame retardant layer slightly powdered after the salt spray test, and the flame retardant rating dropped to UL94 V-1. Comparative Example 2 had an interlaminar peel strength of only 1.5N / mm and a water pressure test leakage of 0.015mL / min. Comparative Example 3 had an interlaminar peel strength of 1.4N / mm, a flame retardant rating of UL94 V-1, and a water pressure leakage of 0.020mL / min. Comparative Example 4 had a low-temperature impact strength of only 4.8kJ / m at -30℃. 2 The filler has a water absorption expansion rate of 20.5%, the sheath cracks and delaminates after salt spray testing, and the water pressure leakage is 0.035 mL / min. This fully demonstrates the significant advantages of the technical solution of this invention in simultaneously improving the waterproof sealing performance, interlayer structural stability, low temperature environment adaptability, salt spray corrosion resistance and flame retardant reliability of marine communication cables. It fundamentally solves the problems of water intrusion, interlayer delamination, structural deformation and insufficient tolerance to extreme environments in the existing technology.

[0069] Therefore, the above-mentioned waterproof marine communication cable and its preparation method effectively solve the problems of water intrusion, interlayer peeling, structural deformation, low-temperature brittleness, and imbalance between salt spray resistance and flame retardancy in existing marine communication cables, significantly improving the overall service performance and reliability of the cable and making it suitable for the harsh operating environment of ships.

[0070] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0071] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A waterproof marine communication cable, comprising a conductor, characterized in that, The following functional layers are sequentially coated on the conductor from the inside out: a polyethylene composite insulation layer, a rubber composite water-blocking layer, a modified filler layer, a compatibility flame-retardant layer, a low-temperature toughening inner liner layer, and a salt spray resistant outer sheath layer; wherein, the polyethylene composite insulation layer is made of raw materials including low-density polyethylene, ethylene-vinyl acetate copolymer, and hydrophobic modified nanofillers; the rubber composite water-blocking layer is made of raw materials including rubber, compatibilizer, and vulcanizing agent; the modified filler layer is made of raw materials including hydrophobic modified diatomaceous earth and water-absorbing resin; the compatibility flame-retardant layer is made of raw materials including resin matrix, hydrophobic modified flame-retardant filler, and halogen-free intumescent flame retardant; the low-temperature toughening inner liner layer is made of raw materials including rubber matrix and polyolefin elastomer; and the salt spray resistant outer sheath layer is made of raw materials including rubber, salt spray resistant modifier, and inorganic flame-retardant filler.

2. The waterproof marine communication cable according to claim 1, characterized in that, The weight proportions of each raw material in the polyethylene composite insulation layer are as follows: 73-77 parts low-density polyethylene, 13-15 parts ethylene-vinyl acetate copolymer, 4.5-5.5 parts hydrophobic modified nanofiller, 2.2-2.8 parts compatibilizer, 0.35-0.45 parts antioxidant, and 0.25-0.35 parts ultraviolet absorber. The weight parts of each raw material in the rubber composite water-blocking layer are as follows: 66-69 parts butyl rubber, 16-19 parts compatibilizer, 3.5-4.5 parts talc, 3.2-3.8 parts tackifier, 1.3-1.4 parts sulfur, and 0.6-0.7 parts antioxidant.

3. The waterproof marine communication cable according to claim 1, characterized in that, The weight parts of each raw material in the modified filler layer are: 62-68 parts of hydrophobic modified diatomaceous earth, 21-24 parts of polypropylene fiber, 6-7 parts of fumed silica, and 3.5-4.5 parts of water-absorbing resin. The weight proportions of each raw material in the compatibility flame retardant layer are as follows: 46-49 parts phenolic resin, 26-29 parts hydrophobically modified flame retardant filler, 36-39 parts high-density polyethylene, 3.2-3.8 parts melamine cyanurate, 4.5-5.5 parts compatibilizer, 13-14 parts halogen-free intumescent flame retardant, 6.5-7.5 parts antimony trioxide, 2.2-2.8 parts zinc borate, and 5.2-5.8 parts Ca / Zn composite stabilizer.

4. A waterproof marine communication cable according to claim 1, characterized in that, The weight proportions of each raw material in the low-temperature toughened inner liner are as follows: 41-44 parts of nitrile rubber, 26-29 parts of polyolefin elastomer, 16-19 parts of light calcium carbonate, 5.5-6.5 parts of talc, 2.2-2.8 parts of antioxidant, 3.2-3.8 parts of plasticizer, and 4.2-4.8 parts of stabilizer; The weight proportions of each raw material in the salt spray resistant outer sheath layer are as follows: 23-24 parts styrene-butadiene rubber, 19.5-23.5 parts salt spray resistant modifier, 41-44 parts low-density polyethylene, 17-19 parts nylon, 18.5-19.5 parts magnesium hydroxide, 26-29 parts aluminum hydroxide, 1.2-1.8 parts filler dispersant, 2.2-2.8 parts antioxidant, and 8.5-9.5 parts vulcanizing agent.

5. A waterproof marine communication cable according to claim 1, characterized in that, The hydrophobic modified nanofiller is stearic acid modified nano-silica with a particle size range of 100-200 nm; the hydrophobic modified flame retardant filler in the compatible flame retardant layer is stearic acid modified magnesium hydroxide with a particle size range of 5-10 μm.

6. A waterproof marine communication cable according to claim 1, characterized in that, The compatibilizer in the rubber composite water-blocking layer is chlorinated polyethylene, and the tackifier is polyisobutylene; the salt spray resistant modifier in the salt spray resistant outer sheath layer is a mixture of chlorosulfonated polyethylene and zinc powder in a weight ratio of 4-5:

1.

7. A method for preparing a waterproof marine communication cable according to any one of claims 1 to 6, characterized in that, Includes the following steps: S1. The raw materials of each functional layer are premixed and secondary blended and then granulated to obtain raw material particles of each layer. Then, the raw material particles of polyethylene composite insulation layer and rubber composite water-blocking layer are simultaneously co-extruded and coated on the outside of the conductor to form the wire core. S2. Inject the raw material particles of the modified filling layer into the gap of the wire core and compact them. Then, wrap the raw material particles of the compatible flame retardant layer on the outside and perform hot pressing composite. After that, co-extrude the raw material particles of the low temperature toughening inner liner and the salt spray resistant outer sheath layer on the outside of the compatible flame retardant layer to form the cable intermediate. S3. The intermediate body of the cable is cooled in sections, and then water pressure test and low temperature aging pretreatment are carried out in sequence to obtain waterproof marine communication cable.

8. The method for preparing a waterproof marine communication cable according to claim 7, characterized in that, In S1, the premixing process parameters are: temperature 165-175℃, rotation speed 260-290rpm, and time 15-20min; the secondary blending process parameters are: temperature 170-180℃, rotation speed 280-300rpm, and time 20-25min; the particle size of the raw material after granulation is 2-3mm; the simultaneous co-extrusion coating process parameters are: temperature 175-185℃, die pressure 16-17MPa, and extrusion speed 8-10m / min.

9. The method for preparing a waterproof marine communication cable according to claim 7, characterized in that, In S2, the raw material particles are injected using a vacuum filling method, with the vacuum level controlled between -0.065 and -0.075 MPa; the compaction pressure is 6-7 MPa, and the compacted filling density is ≥1.2 g / cm³. 3 The hot-pressing composite process parameters are: temperature 145-155℃, pressure 8.5-9.5MPa, and hot-pressing time 35-50 seconds; the co-extrusion temperature of the low-temperature toughened inner liner is 165-175℃, the co-extrusion temperature of the salt spray resistant outer sheath is 180-190℃, and the die pressure of both co-extrusions is 15-17MPa.

10. The method for preparing a waterproof marine communication cable according to claim 7, characterized in that, In S3, segmented cooling includes sequential water cooling and air cooling. The water cooling temperature is 22-28℃ and the cooling time is 3-5 min, while the air cooling is room temperature cooling and the cooling time is 5-8 min. The process parameters for water pressure testing are: pressure 1.2 MPa, pressure holding time 2 hours, and leakage ≤0.01 mL / min. The process parameters for low-temperature aging pretreatment are: temperature -30℃, time 48 hours, and the screening criteria are no interlayer delamination, no cracks, and no deformation.

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