Solvent-resistant and corrosion-resistant cable and method of making same

Abstract

This invention relates to the field of corrosion-resistant special cables, specifically to a solvent-resistant and corrosion-resistant cable and its manufacturing method, comprising a conductor unit, an insulation protection unit, a shielding unit, a barrier protection unit, and an outer sheath unit arranged sequentially. The conductor unit is made of oxygen-free copper wire stranded together, with gaps filled with fluoroether-based corrosion-resistant sealant and cured at high temperature. The insulation protection unit is a three-layer co-extruded structure of modified cross-linked polyethylene with added nano-montmorillonite. The shielding unit is a double-layer reverse braided tin-plated copper wire with a polyurethane corrosion-resistant passivation coating on the surface. The barrier protection unit is a double-layer overlapping wrapping of aluminum-plastic composite tape and water-blocking and corrosion-resistant composite tape. This invention significantly improves the service stability and service life of the cable in complex corrosive environments, eliminates the need for additional corrosion-resistant outer sheath structures, reduces engineering application costs, and is suitable for power transmission needs in various scenarios such as chemical, marine, and new energy industries, possessing high application value.

Description

Technical Field

[0001] This invention relates to the field of corrosion-resistant special cable technology, and more particularly to a solvent-resistant and corrosion-resistant cable and its preparation method. Background Technology

[0002] Currently, the mainstream solvent-resistant and corrosion-resistant cables in the industry mainly fall into two technical categories. The first is a single-layer special polymer sheath solution, typically using polyvinyl chloride, neoprene rubber, or ordinary polytetrafluoroethylene as the outer sheath material, combined with a conventional cross-linked polyethylene insulation layer and a single-layer copper wire shielding structure. The advantage of this solution is its simple manufacturing process and low cost, which can meet the short-term use requirements in environments with mild acids and alkalis and ordinary mineral oils. It is currently widely used in indoor wiring in ordinary chemical workshops and in the support of conventional equipment. Its protection principle relies on the chemical stability of the single polymer material itself to achieve dielectric barrier. To improve weather resistance, a small amount of antioxidants, ultraviolet absorbers, and other additives are usually added to the sheath material. The service life can reach 3 to 5 years in non-severe corrosive environments.

[0003] The second type is a multi-layer simplified composite structure. This involves adding an aluminum-plastic composite tape wrapping barrier layer to the conventional cable structure. The outer sheath uses chlorinated polyethylene or fluororubber-modified polyolefin material, and the insulation layer uses ethylene propylene rubber. This type of solution offers significantly improved solvent resistance compared to a single-layer structure, and can withstand intermittent contact with moderate concentrations of acids and alkalis, as well as common organic solvents. It accounts for over 60% of applications in outdoor chemical pipelines and offshore equipment. Its core improvement lies in the physical barrier formed by the aluminum layer, which slows down the penetration rate of corrosive media into the internal structure. Simultaneously, the swelling resistance of the modified polyolefin material is improved by approximately 30% compared to traditional polymers, making it suitable for most low- to medium-intensity corrosion scenarios.

[0004] However, the two existing technical solutions still have significant shortcomings under long-term high-intensity corrosion conditions. On the one hand, the material system's resistance to media penetration is insufficient. Existing polytetrafluoroethylene (PTFE) sheath materials have not undergone molecular chain cross-linking modification and surface fluorination treatment. When exposed to strong polar organic solvents such as xylene and acetone for a long time, swelling is likely to occur, leading to an expansion of the molecular chain gaps. Corrosive media can gradually penetrate the sheath layer and invade the interior, causing insulation layer aging, shielding layer corrosion, and ultimately resulting in the failure of the cable's electrical performance. The continuous service life in strong solvent environments is usually no more than one year.

[0005] On the other hand, the structural protection system suffers from a lack of in-depth defense. Existing solutions only focus on the outer sheath and a single barrier layer design, failing to provide specific protection for vulnerable areas such as conductor gaps, interlayer interfaces, and shielding surface, which are susceptible to corrosive media penetration. Conductor stranding gaps lack anti-corrosion filling, interlayer interfaces lack sealing and corrosion-resistant structures, and the shielding layer lacks a corrosion-resistant coating. Once the outer sheath experiences minor damage or media penetration breaches the barrier layer, corrosion rapidly spreads inward, leading to cable failures such as localized breakdown and signal attenuation within 3 to 6 months. Furthermore, existing solutions lack performance adaptability. Most products are designed for only a single corrosive medium and cannot withstand mixed corrosive environments of strong solvents, strong acids, and strong alkalis simultaneously. Moreover, the corrosion resistance and insulation performance of high-voltage products are difficult to balance synergistically. High-corrosion resistant cables of 10kV and above have long relied on imports, with procurement costs 3 to 5 times higher than ordinary domestic cables, and long maintenance response times, severely hindering the localization process of related industries.

[0006] The industry urgently needs to develop a new type of solvent-resistant and corrosion-resistant cable with multi-level collaborative protection capabilities, tolerance to various types of complex corrosive media, and adaptability to high-voltage transmission requirements. This is to address the pain points of existing technologies, such as short service life, insufficient protection reliability, and high overall cost in high-intensity corrosion scenarios, and to meet the long-term stable operation requirements of extreme industrial scenarios. Summary of the Invention

[0007] To address the shortcomings of existing solvent-resistant and corrosion-resistant cables, such as easy swelling and penetration, easy corrosion intrusion between layers, and inability to adapt to mixed corrosion conditions, this invention provides a solvent-resistant and corrosion-resistant cable and its preparation method.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A solvent-resistant and corrosion-resistant cable comprises, from the inside out, a conductor, an insulation layer, a sealing and corrosion-resistant layer, a shielding layer, a buffer layer, a barrier and protective layer, and an outer sheath; The conductor is made of multi-strand stranded tin-plated oxygen-free copper wire. The surface of each copper wire is pre-coated with a nano-silane passivation film. The tin plating layer thickness is 1μm to 3μm. The conductor stranding pitch ratio is controlled to be 12 to 18. The stranding gap is filled with corrosion-resistant and alkali-free glass fiber rope. The surface of the filling rope is impregnated with a fluorine anti-corrosion coating. The filling density is not less than 95%. The insulating layer is made of cross-linked modified silicone rubber material, with a thickness of 0.8 mm to 1.5 mm. The interface between the insulating layer and the conductor is coated with an organosilicon adhesive, and the interlayer peel strength is not less than 3 N / mm. The sealing and corrosion-resistant layer adopts a structure of overlapping and wrapping water-swellable waterproof tape and polytetrafluoroethylene film, with a wrapping overlap rate of 20% to 30% and a total thickness of 0.12 mm to 0.2 mm. The shielding layer adopts a composite structure of tin-plated copper wire braiding and aluminum foil wrapping. The diameter of a single tin-plated copper wire is 0.1 mm to 0.2 mm, the braiding density is not less than 95%, the aluminum foil overlap rate is not less than 40%, and the surface of the shielding layer is coated with an oil-resistant and corrosion-resistant coating with a coating thickness of 5 μm to 10 μm. The buffer layer adopts a fluororubber modified polyimide film wrapping structure with a wrapping overlap rate of 25% to 35%, a film thickness of 0.05 mm to 0.1 mm, and 2 to 3 wrapping layers. The barrier protective layer adopts a metallized aramid fabric weaving structure with a weaving density of not less than 85%, and the metal plating layer is a nickel-chromium alloy with a plating thickness of 2μm to 5μm. The outer sheath is made of modified polytetrafluoroethylene composite material, with a thickness of 1.2 mm to 2.5 mm. The surface of the outer sheath is subjected to plasma fluorination treatment with a treatment depth of 100 nm to 300 nm.

[0009] Preferably, the crosslinked modified silicone rubber material is prepared by radiation crosslinking of a mixture of methyl vinyl silicone rubber, fumed silica, vinyltriethoxysilane, dicumyl peroxide, nano titanium dioxide, fluorosilane coupling agent, and anti-aging additive; wherein the mass fraction of methyl vinyl silicone rubber is 70 to 85 parts, the mass fraction of fumed silica is 15 to 25 parts, the mass fraction of vinyltriethoxysilane is 2 to 5 parts, the mass fraction of dicumyl peroxide is 0.5 to 1.5 parts, the mass fraction of nano titanium dioxide is 3 to 8 parts, the mass fraction of fluorosilane coupling agent is 1 to 3 parts, and the mass fraction of anti-aging additive is 0.5 to 2 parts. The anti-aging additive is obtained by mixing nickel dibutyldithiocarbamate and hindered phenolic antioxidant at a mass ratio of 1:1 to 2. After the cross-linked modified silicone rubber is heat-aged at 200°C for 168 hours, the mechanical property retention rate is not less than 90%, and after being soaked in 10% hydrochloric acid solution for 72 hours, the volume change rate is not more than 2%.

[0010] Preferably, the modified polytetrafluoroethylene composite material is prepared by mixing polytetrafluoroethylene, perfluoropropyl vinyl ether, polyphenylene sulfide, nano boron nitride, graphite powder, polyimide micro powder and compatibilizer and then molding and sintering. The components are: polytetrafluoroethylene (PTFE) in the amount of 65 to 80 parts by mass, perfluoropropyl vinyl ether in the amount of 8 to 15 parts by mass, polyphenylene sulfide in the amount of 5 to 10 parts by mass, nano boron nitride in the amount of 2 to 6 parts by mass, graphite powder in the amount of 1 to 4 parts by mass, polyimide micro powder in the amount of 3 to 7 parts by mass, and compatibilizer in the amount of 1 to 3 parts by mass. The compatibilizer is maleic anhydride-grafted polytetrafluoroethylene. After being immersed in a mixed organic solvent of xylene, acetone and ethyl acetate for 72 hours, the volume change rate of the modified polytetrafluoroethylene composite material does not exceed 1%, the Shore hardness is not lower than Shore D65, and the wear resistance is improved by more than 40% compared with pure polytetrafluoroethylene.

[0011] Preferably, the tin-plated oxygen-free copper wire of the conductor is subjected to plasma surface activation treatment before stranding, with an activation power of 300W to 500W and a treatment time of 10s to 30s; The nano-silane passivation film was prepared by coating with a fluorinated silane hydrolysate. After coating, the drying temperature was 80℃ to 100℃ and the drying time was 5 min to 10 min. The fluorine anti-corrosion coating of the corrosion-resistant and alkali-free glass fiber rope is prepared by impregnation with perfluoropolyether coating. The curing temperature after impregnation is 120℃ to 150℃, the curing time is 20min to 30min, and the coating thickness is 10μm to 20μm.

[0012] Preferably, the surface of the polytetrafluoroethylene film of the sealing and corrosion-resistant layer is corona treated, the surface tension is not less than 42 dyn / cm, the expansion ratio of the water-resistant tape that expands when exposed to water is not less than 20 times, the polytetrafluoroethylene film is located on the outside when it is stacked and wrapped, the wrapping tension is controlled at 2N to 6N, and after wrapping, it is ironed and shaped by hot rollers at a temperature of 60°C to 80°C and an ironing pressure of 0.1MPa to 0.3MPa.

[0013] Preferably, the tin-plated copper wire braiding pitch of the shielding layer is 10mm to 20mm, the aluminum foil is double-sided tin-plated aluminum foil with a thickness of 0.03mm to 0.05mm, and the oil-resistant and anti-corrosion coating is prepared by spraying epoxy resin-based oil-resistant coating. The curing temperature after spraying is 100℃ to 120℃, the curing time is 15min to 25min, and the coating adhesion is not lower than level 1.

[0014] Preferably, the fluororubber-modified polyimide film of the buffer layer is prepared by composite of polyimide substrate and fluororubber coating, the thickness of fluororubber coating is 20% to 30% of the total thickness of film, the tensile strength of film is not less than 150 MPa, the heat shrinkage rate at 150°C is not more than 0.5%, and the interlayer bonding strength after wrapping is not less than 2 N / mm.

[0015] Preferably, the metallized aramid fabric of the barrier protective layer has a basis weight of 80 g / m² to 120 g / m², the nickel-chromium alloy plating has a nickel content of 70% to 80% and a chromium content of 20% to 30%, and the surface is coated with fluorine conformal paint after weaving, with a coating thickness of 3 μm to 8 μm. After curing, the surface resistance is not higher than 10 Ω / □, and it can withstand immersion in 10% sodium hydroxide solution for 72 hours without rust.

[0016] A preferred method for preparing a solvent-resistant and corrosion-resistant cable includes the following steps: S1. Conductor preparation: Select oxygen-free copper wire with a tin-plated layer thickness of 1μm to 3μm, first perform plasma surface activation treatment at a power of 300W to 500W for 10s to 30s, then coat it with a fluorinated silane hydrolysate and dry it at 80℃ to 100℃ for 5min to 10min to form a nano-silane passivation film; then strand the treated tin-plated oxygen-free copper wire with a pitch ratio of 12 to 18, and simultaneously fill it with corrosion-resistant alkali-free glass fiber rope with a fluorine anti-corrosion coating on the surface during the stranding process, with a filling density of not less than 95%, and control the stranding tension at 5N to 15N to obtain the shaped conductor; S2. Insulation layer extrusion: Crosslinked modified silicone rubber material is coated onto the surface of the molded conductor using an extruder. Before extrusion, an organosilicon binder is uniformly coated on the surface of the molded conductor. The extrusion temperature is controlled at 120℃ to 160℃, the screw speed is controlled at 20r / min to 50r / min, and the extrusion die stretch ratio is 1.2 to 1.8. After extrusion, electron beam radiation crosslinking is performed with a radiation dose of 150kGy to 250kGy and a crosslinking degree controlled at 80% to 90%, to obtain the insulated wire core. S3. Sealing and corrosion-resistant layer wrapping: Water-swellable waterproof tape and polytetrafluoroethylene film are overlapped and wrapped around the surface of the insulated wire core, with the polytetrafluoroethylene film on the outside. The wrapping overlap rate is controlled at 20% to 30%, and the wrapping tension is 2N to 6N. After wrapping, the wire core is ironed and shaped with a hot roller at 60℃ to 80℃ and 0.1MPa to 0.3MPa to obtain the wire core with a sealing and corrosion-resistant layer. S4. Shielding layer preparation: First, double-sided tin-plated aluminum foil is wrapped around the surface of the wire core with the sealing and corrosion-resistant layer, with an overlap rate of not less than 40%. Then, tin-plated copper wire with a single wire diameter of 0.1 mm to 0.2 mm is used for braiding, with a braiding density of not less than 95% and a braiding pitch of 10 mm to 20 mm. After braiding, an epoxy resin-based oil-resistant coating is sprayed onto the surface of the shielding layer and cured at 100°C to 120°C for 15 min to 25 min to form an oil-resistant and corrosion-resistant coating with a thickness of 5 μm to 10 μm, thus obtaining the wire core with the shielding layer. S5. Buffer layer wrapping: A fluororubber modified polyimide film is wrapped around the surface of the shielded core with an overlap rate of 25% to 35%. The number of wrapping layers is 2 to 3, and the wrapping tension is controlled at 3N to 8N. After wrapping, the core is heat-dried at 80℃ to 100℃ for 10 to 20 minutes to obtain a core with a buffer layer. S6. Barrier protective layer braiding: Metallized aramid cloth is braided on the surface of the core with buffer layer, with a braiding density of not less than 85% and a braiding tension controlled at 4N to 10N. After braiding, the surface is sprayed with fluorine three-proof paint and cured at room temperature for 24 hours to form a protective coating with a thickness of 3μm to 8μm, thus obtaining a core with barrier protective layer. S7. Outer Sheath Extrusion and Post-treatment: Modified polytetrafluoroethylene composite material is coated onto the surface of the wire core with a barrier protective layer using a plunger extruder. The extrusion temperature is controlled at 330℃ to 380℃. After extrusion, segmented sintering is performed at 200℃ to 250℃, 300℃ to 350℃, and 380℃ to 420℃, with each segment sintering for 10 to 20 minutes. After sintering, stepped cooling is adopted, with the cooling temperature decreasing to 250℃ to 300℃, 150℃ to 200℃, and room temperature, respectively. After cooling, the outer sheath surface is subjected to plasma fluorination treatment with a treatment power of 500W to 800W, a treatment time of 30s to 60s, and a treatment depth controlled at 100nm to 300nm, to obtain a solvent-resistant and corrosion-resistant cable.

[0017] Preferably, in step S1, the preparation process of the fluorine anti-corrosion coating of the corrosion-resistant and alkali-free glass fiber rope is as follows: the alkali-free glass fiber rope is immersed in the perfluoropolyether coating for 10 to 20 seconds, and then cured at 120°C to 150°C for 20 to 30 minutes. The coating thickness is controlled to be 10 μm to 20 μm, and the coating adhesion after curing is not lower than grade 0.

[0018] Preferably, in step S5, the preparation process of the fluororubber modified polyimide film is as follows: a fluororubber emulsion is uniformly coated on the surface of the polyimide film, with a coating thickness of 10 μm to 30 μm. After coating, the film is vulcanized at 150°C to 180°C for 20 min to 30 min to obtain a composite film with a fluororubber coating thickness accounting for 20% to 30% of the total thickness and a tensile strength of not less than 150 MPa.

[0019] Preferably, after step S7, the finished cable is subjected to air tightness test, solvent immersion test and electrical performance test in sequence; the air tightness test pressure is 0.2MPa to 0.5MPa, the pressure holding time is 5min to 10min, and the pressure drop is not more than 0.02MPa to be qualified; the solvent immersion test uses a mixed medium of xylene, acetone, 10% hydrochloric acid and 10% sodium hydroxide, and the sheath volume change rate is not more than 1% after immersion for 72h to be qualified; the electrical performance test includes insulation resistance of not less than 100MΩ·km and power frequency withstand voltage of 2500V AC for 1min without breakdown.

[0020] The present invention has the following beneficial effects: This invention utilizes a cross-linked modified fluoropolymer outer sheath combined with surface fluorination treatment technology to achieve a dual improvement in the molecular chain density and solvent resistance of the outer sheath material. This effectively reduces the penetration rate of highly polar organic solvents, preventing swelling and cracking of the sheath after prolonged contact with corrosive media. Compared to traditional PTFE sheaths, the solvent penetration resistance is significantly enhanced, greatly slowing down the intrusion rate of corrosive media into the cable's internal structure. This technological improvement directly addresses the shortcomings of existing single sheath materials, such as insufficient solvent resistance and susceptibility to media penetration, significantly enhancing the long-term reliability of the cable's outer protective layer.

[0021] This invention employs a multi-layered, collaborative protection structure. Corrosion-resistant sealant is filled between conductor strands, a water- and corrosion-resistant composite tape is wrapped around the insulation layer, and a corrosion-resistant passivation layer is plated on the shielding layer. Simultaneously, hot-melt adhesive bonding and sealing structures are used between each structural layer, constructing a complete corrosion protection barrier from the inside out. Even if the outer sheath suffers minor damage, it can effectively prevent corrosive media from spreading layer by layer inward, avoiding problems such as conductor corrosion, insulation failure, and shielding layer performance degradation. This structural design fills the gaps in existing technologies where interlayer protection is lacking and weak points are easily corroded, achieving corrosion risk control throughout the cable structure and significantly improving operational stability under complex operating conditions.

[0022] This invention, through synergistic optimization of the material system and structure, enables the cable to withstand the combined effects of multiple types of corrosive media, including highly polar organic solvents, strong acids, strong alkalis, and salt spray. It also adapts to transmission requirements across all voltage levels from 1kV to 35kV, eliminating the need for customized products for different corrosive scenarios. This makes it widely applicable to various high-intensity corrosive industrial environments such as petrochemicals, marine engineering, metallurgy, and new energy power generation. Its applicability covers the vast majority of industrial corrosion applications, eliminating the need for additional protective sleeves or other auxiliary facilities. This effectively reduces procurement and maintenance costs for downstream users, possessing significant industry promotion value and contributing to the domestic substitution process of special cables in related fields. Attached Figure Description

[0023] Figure 1 This is a schematic flowchart of a method for preparing a solvent-resistant and corrosion-resistant cable proposed in this invention. Figure 2 This is a bar chart comparing the aging rate of cable sheaths under different corrosive environments according to the present invention. Figure 3 This is a line graph showing the change in cable insulation performance under different service durations according to the present invention. Detailed Implementation

[0024] The following will refer to the appendices in the embodiments of the present invention. Figure 1-3The technical solutions in the embodiments of the present invention are clearly and completely described herein. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] This invention discloses a solvent-resistant and corrosion-resistant cable, comprising a conductor unit, an insulation protection unit, a shielding unit, a barrier protection unit, and an outer sheath unit.

[0026] The conductor unit is formed by stranding multiple strands of high-purity oxygen-free copper wire. During the stranding process, fluoroether-based corrosion-resistant sealant is evenly filled between the copper wires. After filling, the sealant is completely cured by high-temperature setting at 120℃ for 30 minutes, and the filling density reaches more than 98%. This prevents corrosive media from penetrating into the conductor stranding gaps and solves the defects of existing cable conductors that lack anti-corrosion filling and are prone to longitudinal corrosion diffusion.

[0027] The insulation protection unit is co-extruded and wrapped around the outside of the conductor unit. It is made of modified cross-linked polyethylene material with 2% to 5% nano-montmorillonite filler added to the material to improve the solvent penetration resistance and electrical insulation strength of the insulation layer. The volume resistivity is not less than 1×10^16 Ω·cm, which can withstand long-term stable transmission of voltage levels of 10kV and above, while preventing corrosive media from contacting the conductor unit.

[0028] The shielding unit is located outside the insulating protection unit and adopts a double-layer reverse braided structure of tin-plated copper wire with a braiding density of not less than 90% and a tin plating layer thickness of not less than 8μm on the surface of the copper wire. At the same time, a polyurethane corrosion-resistant passivation coating is applied to the surface of the braided layer with a coating thickness of not less than 15μm. This not only meets the electromagnetic shielding requirements but also prevents corrosive media from directly contacting the copper wire and causing corrosion. This solves the defects of existing shielding layers that lack corrosion-resistant treatment and are prone to oxidation failure.

[0029] The barrier protection unit wraps around the outside of the shielding unit, using a double-layer overlapping wrapping structure of aluminum-plastic composite tape and water- and corrosion-resistant composite tape. The wrapping overlap rate is not less than 25%, the aluminum layer thickness of the aluminum-plastic composite tape is not less than 0.05mm, and the water- and corrosion-resistant composite tape contains super absorbent resin particles. When it comes into contact with water or corrosive media, the expansion ratio is not less than 300 times, forming a radial physical barrier to block the inward penetration path of corrosive media.

[0030] The outer sheath unit is extruded onto the outside of the barrier protection unit and is made of cross-linked modified ethylene-tetrafluoroethylene copolymer material. The material is cross-linked by electron beam irradiation, with a cross-linking degree of not less than 80%. The thickness of the outer sheath layer is set to 1.5mm~3.5mm according to the voltage level. The surface of the outer sheath is treated with gas phase fluorination, and the fluorine content of the surface layer is not less than 65%, forming a dense fluorinated passivation layer with a surface energy of less than 18mN / m. It can effectively resist the swelling and penetration of strong polar organic solvents and withstand immersion in strong solvents such as toluene and acetone for 30 days with a volume change rate of less than 0.8%, which solves the defects of existing sheath materials that are easy to swell and easy to penetrate by the medium. This invention also discloses that the stranding pitch ratio of the conductor unit is controlled between 12 and 16 times, and tension closed-loop control is adopted during the stranding process. The tension deviation of a single copper wire is controlled within ±5%, ensuring that the roundness of the conductor surface is not less than 95%, avoiding insufficient local thickness of the insulation layer due to conductor surface protrusion, while improving the filling uniformity of the corrosion-resistant sealant, avoiding filling gaps, and further enhancing the longitudinal corrosion resistance of the conductor unit.

[0031] This invention also discloses an insulation protection unit formed by a three-layer co-extrusion process. The inner layer is a semi-conductive resistive water buffer layer with a thickness of 0.5mm to 0.8mm, the middle layer is a cross-linked polyethylene main insulation layer, and the outer layer is a semi-conductive shielding layer with a thickness of 0.3mm to 0.5mm. During the three-layer co-extrusion process, the temperature gradient is controlled within 10℃ to ensure that there is no obvious interface between the layers, avoid the penetration of corrosive media along the interlayer gaps, and at the same time increase the partial discharge initiation voltage of the insulation layer, thereby reducing the insulation aging rate during long-term operation.

[0032] This invention also discloses that the inner layer of the shielding unit has a braiding pitch of 8 to 10 times the outer diameter of the braiding layer, and the outer layer has a braiding pitch of 10 to 12 times the outer diameter of the braiding layer. The two layers are braided in opposite directions, which can offset the torsional stress during operation, prevent the braiding layer from loosening or breaking, and improve the electromagnetic shielding effectiveness. The shielding effectiveness is not less than 60dB in the frequency range of 10MHz to 1GHz, taking into account both electromagnetic shielding performance and structural stability.

[0033] In this invention, the wrapping tension of the barrier protection unit is also disclosed to be controlled between 10N and 15N. After wrapping, hot melt adhesive is sprayed to ensure that the overlap of the composite tape is completely bonded to the outside of the shielding unit, with a bonding strength of not less than 1.2N / mm. This avoids the composite tape from warping or gaps, ensuring the continuity of radial barrier. Even if the outer sheath is slightly damaged, it can slow down the penetration rate of corrosive media.

[0034] This invention also discloses that the extrusion temperature of the outer sheath unit is controlled between 280℃ and 320℃, an online thickness measuring device is used during the extrusion process, the thickness deviation is controlled within ±0.1mm, the gas phase fluorination treatment time is controlled between 10min and 15min, and the treatment temperature is between 50℃ and 60℃, ensuring that the fluorinated layer depth is not less than 20μm, so that the outer sheath has both excellent solvent resistance and mechanical strength, tensile strength not less than 15MPa, elongation at break not less than 200%, and can adapt to bending and tensile stress during installation.

[0035] This invention also discloses that each structural layer is coated with a fluororubber adhesive, and the peel strength of the adhesive after curing is not less than 0.8 N / mm, so that the entire cable structure forms a continuous sealed whole, eliminating interlayer gaps, preventing the spread of corrosive media along the interlayer interface, and achieving a synergistic anti-corrosion effect of the entire structure.

[0036] Experimental Materials and General Methods Reagents and raw materials: high-purity oxygen-free copper wire, fluoroether-based corrosion-resistant sealant, modified cross-linked polyethylene material (with 3% nano montmorillonite added, melt index 1.8g / 10min), tin-plated copper wire, polyurethane corrosion-resistant coating, aluminum-plastic composite tape (aluminum layer thickness 0.05mm, PET layer thickness 0.05mm), water-blocking and corrosion-resistant composite tape, cross-linked modified ethylene-tetrafluoroethylene copolymer (ETFE, grade ETFE-850, melt index 3.2g / 10min), fluororubber adhesive (grade FKM-G, curing temperature 100℃), toluene, acetone, 5% sodium chloride salt spray solution, 10% sulfuric acid solution, 10% sodium hydroxide solution.

[0037] General manufacturing process: All cables in the examples and comparative examples were manufactured using the same cabling equipment. The conductor stranding speed was 50 rpm, the insulation co-extrusion temperature was 180℃~220℃, the shielding braiding speed was 120 rpm, the wrapping tension was 12N, the outer sheath extrusion temperature was 280℃~320℃, and the gas phase fluorination treatment was carried out in a closed reactor with a fluorine concentration of 20% and nitrogen as the balance gas.

[0038] Performance testing methods: (1) Solvent immersion test: According to GB / T9345.4-2008, the cable sample was immersed in a mixed solution of toluene / acetone of equal volume and soaked at 25°C for 30 days. The sheath volume change rate and tensile strength retention rate before and after immersion were tested.

[0039] (2) Salt spray corrosion test: According to GB / T10124-2022, a neutral salt spray test was adopted at a temperature of 35℃, a spray volume of 1~2mL / 80cm²·h, and continuous spraying for 1000h. The shielding layer resistance change rate and insulation resistance retention rate were tested.

[0040] (3) Interlayer bond strength test: Using an electronic universal testing machine, adjacent structural layers are peeled off at a rate of 50 mm / min, the peel force per unit length is recorded, and the bond strength is calculated.

[0041] (4) Permeability coefficient test: The solvent permeability coefficient of the sheath material was tested using the cup method at a temperature of 25°C for 72 hours.

[0042] (5) High and low temperature cycle test: According to GB / T2423.1-2008, cycle 100 times between -40℃ and 60℃, each cycle lasting 4 hours, observe whether the sheath cracks, and test the change in insulation resistance.

[0043] Example 1: Low-fluorine content sheath, low filler density parameter group Sample preparation Conductor unit preparation: Take 56 high-purity oxygen-free copper wires with a diameter of 0.2 mm and strand them together using a stranding process with a stranding pitch ratio of 12. During the stranding process, fill with fluoroether-based corrosion-resistant sealant, and control the filling density to 98%. After filling, place them in a 120℃ forced-air drying oven for 30 min to cure, and obtain conductor units with a diameter of 1.8 mm and a conductor surface roundness of 95%.

[0044] Insulation protection unit preparation: An insulation layer is wrapped around the outside of the conductor unit using a three-layer co-extrusion process. The inner semi-conductive resistive water buffer layer has a thickness of 0.5 mm, the middle modified cross-linked polyethylene main insulation layer has a thickness of 1.0 mm, and the outer semi-conductive shielding layer has a thickness of 0.3 mm. The co-extrusion temperatures from the barrel to the die are set to 180℃, 190℃, 200℃, and 210℃ respectively, with the temperature gradient controlled within 8℃. After cooling, the insulated wire core is obtained, and the volume resistivity of the insulation layer is measured to be 1.2×10^16 Ω·cm.

[0045] Shielding unit fabrication: A tin-plated copper wire shielding layer is braided on the outside of the insulated core. The inner braiding pitch is 8 times the outer diameter of the braiding layer, and the outer braiding pitch is 10 times the outer diameter of the braiding layer. The braiding density is 90%, and the tin plating layer on the copper wire surface is 8μm thick. After braiding, a polyurethane corrosion-resistant passivation coating is applied online with a coating thickness of 15μm. The coating is then cured in an 80℃ oven for 20min. The shielding effectiveness of the shielding layer at 100MHz is 62dB.

[0046] Preparation of the barrier protection unit: An aluminum-plastic composite tape and a water-blocking and corrosion-resistant composite tape are overlapped and wrapped around the outside of the shielding unit. The aluminum layer thickness of the aluminum-plastic composite tape is 0.05mm, the surface density of the water-blocking and corrosion-resistant composite tape is 120g / m², the wrapping overlap rate is 25%, the wrapping tension is controlled at 10N, and hot melt adhesive is sprayed after wrapping. The bonding strength test after the hot melt adhesive is cured is 1.2N / mm.

[0047] Outer sheath unit preparation: Cross-linked modified ETFE material was extruded onto the outside of the barrier protection unit using an extruder. The extrusion temperatures from the barrel to the die were set to 280℃, 290℃, 300℃, and 310℃ respectively. The outer sheath thickness was controlled at 1.5mm with a thickness deviation of ±0.08mm. After extrusion, the material was cross-linked by electron beam irradiation at a dose of 150kGy, and the degree of cross-linking was tested to be 80%. Subsequently, the cable sample was placed in a gas phase fluorination reactor, and a 20% concentration of fluorine-nitrogen mixed gas was introduced. The treatment temperature was 50℃, and the treatment time was 10min, resulting in an outer sheath with a surface fluorinated layer depth of 20μm. The surface fluorine content was tested to be 65%, and the surface energy was 17.8mN / m.

[0048] Interlayer bonding treatment: Fluororubber adhesive is applied between every two layers of the structure with a coating thickness of 0.05 mm. It is cured at 100°C for 10 min. The interlayer peel strength test result is 0.8 N / mm. Finally, the solvent-resistant and corrosion-resistant cable sample of this embodiment is obtained.

[0049] Performance testing The samples in this embodiment were subjected to performance tests according to general testing methods, and the results were recorded in the subsequent data table. This embodiment verifies the effectiveness of the lower limit parameters of the technical solution by setting minimum fluorine content sheath and minimum filler density parameters, which can solve the defects of existing cable sheaths being prone to swelling and conductor gaps being prone to penetration.

[0050] Example 2: Medium fluorine content sheath, medium filler density parameter group Sample preparation Conductor unit preparation: 56 high-purity oxygen-free copper wires with a diameter of 0.2 mm were taken and stranded using a stranding process with a stranding pitch ratio of 14. During the stranding process, fluoroether-based corrosion-resistant sealant was filled, and the filling density was controlled to be 98.5%. After filling, the conductor unit was placed in a 120℃ forced-air drying oven for 30 min to cure, resulting in a conductor unit with a diameter of 1.8 mm and a conductor surface roundness of 96%.

[0051] Insulation protection unit preparation: An insulation layer is wrapped around the outside of the conductor unit using a three-layer co-extrusion process. The inner semi-conductive resistive water buffer layer has a thickness of 0.6 mm, the middle modified cross-linked polyethylene main insulation layer has a thickness of 1.0 mm, and the outer semi-conductive shielding layer has a thickness of 0.4 mm. The co-extrusion temperatures from the barrel to the die are set to 185℃, 195℃, 205℃, and 215℃ respectively, with the temperature gradient controlled within 7℃. After cooling, the insulated wire core is obtained, and the volume resistivity of the insulation layer is measured to be 1.5×10^16 Ω·cm.

[0052] Shielding unit fabrication: A tin-plated copper wire shielding layer is braided on the outside of the insulated core. The inner braiding pitch is 9 times the outer diameter of the braiding layer, and the outer braiding pitch is 11 times the outer diameter of the braiding layer. The braiding density is 92%, and the tin plating layer on the copper wire surface is 9μm thick. After braiding, a polyurethane corrosion-resistant passivation coating is applied online with a coating thickness of 18μm. The coating is then cured in an 80℃ oven for 20min. The shielding effectiveness of the shielding layer at 100MHz is 65dB.

[0053] Preparation of the barrier protection unit: An aluminum-plastic composite tape and a water-blocking and corrosion-resistant composite tape are overlapped and wrapped around the outside of the shielding unit. The aluminum layer thickness of the aluminum-plastic composite tape is 0.07mm, the surface density of the water-blocking and corrosion-resistant composite tape is 150g / m², the wrapping overlap rate is 30%, the wrapping tension is controlled at 12N, and hot melt adhesive is sprayed after wrapping. The bonding strength test after the hot melt adhesive is cured is 1.5N / mm.

[0054] Outer sheath unit preparation: Cross-linked modified ETFE material was extruded onto the outside of the barrier protection unit using an extruder. The extrusion temperatures from the barrel to the die were set to 290℃, 300℃, 310℃, and 315℃ respectively. The outer sheath thickness was controlled at 2.0mm with a thickness deviation of ±0.07mm. After extrusion, the material was cross-linked by electron beam irradiation at a dose of 180kGy, and the degree of cross-linking was tested to be 85%. Subsequently, the cable sample was placed in a gas phase fluorination reactor, and a 20% concentration of fluorine-nitrogen mixed gas was introduced. The treatment temperature was 55℃, and the treatment time was 12min, resulting in an outer sheath with a surface fluorinated layer depth of 25μm. The surface fluorine content was tested to be 68%, and the surface energy was 17.2mN / m.

[0055] Interlayer bonding treatment: A fluororubber adhesive with a thickness of 0.06 mm is applied between every two layers of the structure and cured at 100°C for 10 min. The interlayer peel strength test result is 1.0 N / mm, and the solvent-resistant and corrosion-resistant cable sample of this embodiment is finally obtained.

[0056] Performance testing The samples in this embodiment were tested for performance according to general testing methods, and the results were recorded in the subsequent data table. This embodiment verifies the stability of the technical solution under normal operating conditions by setting medium parameter levels, which can solve the defects of existing cables that are prone to interlayer corrosion and shielding layer corrosion.

[0057] Example 3: High fluoride content sheath, high filler density parameter group Sample preparation Conductor unit preparation: Take 56 high-purity oxygen-free copper wires with a diameter of 0.2 mm and strand them together using a stranding process with a stranding pitch ratio of 16. During the stranding process, fill with fluoroether-based corrosion-resistant sealant, and control the filling density to 99%. After filling, place them in a 120℃ forced-air drying oven for 30 min to cure, and obtain conductor units with a diameter of 1.8 mm and a conductor surface roundness of 97%.

[0058] Insulation protection unit preparation: An insulation layer is wrapped around the outside of the conductor unit using a three-layer co-extrusion process. The inner semi-conductive resistive water buffer layer has a thickness of 0.8 mm, the middle modified cross-linked polyethylene main insulation layer has a thickness of 1.0 mm, and the outer semi-conductive shielding layer has a thickness of 0.5 mm. The co-extrusion temperatures from the barrel to the die are set to 190℃, 200℃, 210℃, and 220℃ respectively, with the temperature gradient controlled within 6℃. After cooling, the insulated wire core is obtained, and the volume resistivity of the insulation layer is measured to be 1.8×10^16 Ω·cm.

[0059] Shielding unit fabrication: A tin-plated copper wire shielding layer is braided on the outside of the insulated core. The inner braiding pitch is 10 times the outer diameter of the braiding layer, and the outer braiding pitch is 12 times the outer diameter of the braiding layer. The braiding density is 95%, and the tin plating layer on the copper wire surface is 10μm thick. After braiding, a polyurethane corrosion-resistant passivation coating is applied online with a coating thickness of 20μm. The coating is then cured in an 80℃ oven for 20min. The shielding effectiveness of the shielding layer at 100MHz is 68dB.

[0060] Preparation of the barrier protection unit: An aluminum-plastic composite tape and a water-blocking and corrosion-resistant composite tape are overlapped and wrapped around the outside of the shielding unit. The aluminum layer thickness of the aluminum-plastic composite tape is 0.1mm, the surface density of the water-blocking and corrosion-resistant composite tape is 180g / m², the wrapping overlap rate is 35%, the wrapping tension is controlled at 15N, and hot melt adhesive is sprayed after wrapping. The bonding strength test after the hot melt adhesive is cured is 1.8N / mm.

[0061] Outer sheath unit preparation: Cross-linked modified ETFE material was extruded onto the outside of the barrier protection unit using an extruder. The extrusion temperatures were set sequentially from the barrel to the die: 300℃, 310℃, 315℃, and 320℃. The outer sheath thickness was controlled at 3.5mm with a thickness deviation of ±0.05mm. After extrusion, the material was cross-linked by electron beam irradiation at a dose of 200kGy, and the degree of cross-linking was tested to be 90%. Subsequently, the cable sample was placed in a gas-phase fluorination reactor, and a 20% concentration of fluorine-nitrogen mixed gas was introduced. The treatment temperature was 60℃, and the treatment time was 15min, resulting in an outer sheath with a surface fluorinated layer depth of 30μm. The surface fluorine content was tested to be 70%, and the surface energy was 16.5mN / m.

[0062] Interlayer bonding treatment: A fluororubber adhesive with a thickness of 0.07 mm is applied between every two layers of the structure and cured at 100°C for 10 min. The interlayer peel strength test result is 1.2 N / mm, and the solvent-resistant and corrosion-resistant cable sample of this embodiment is finally obtained.

[0063] Performance testing The samples in this embodiment were subjected to performance tests according to general testing methods, and the results were recorded in the subsequent data table. This embodiment verifies the ultimate protection capability of the technical solution under highly corrosive conditions by setting the highest parameter level, which can solve the defects of existing cables in highly corrosive scenarios, such as short service life and easy failure.

[0064] Example 4: Parameter set for acid and alkali corrosion environments Sample preparation Conductor unit preparation: 56 high-purity oxygen-free copper wires with a diameter of 0.2 mm were taken and stranded using a stranding process with a stranding pitch ratio of 15. During the stranding process, 2% nano-titanium dioxide modified fluoroether corrosion-resistant sealant was added and the filling density was controlled to 98.8%. After filling, the conductor unit was placed in a 120℃ forced-air drying oven for 30 min to cure, resulting in a conductor unit with a diameter of 1.8 mm and a conductor surface roundness of 96.5%.

[0065] Insulation protection unit preparation: An insulation layer is wrapped around the outside of the conductor unit using a three-layer co-extrusion process. The inner semi-conductive resistive water buffer layer has a thickness of 0.7 mm, the middle modified cross-linked polyethylene main insulation layer with 4% nano-montmorillonite has a thickness of 1.2 mm, and the outer semi-conductive shielding layer has a thickness of 0.4 mm. The co-extrusion temperatures from the barrel to the die are set to 188℃, 198℃, 208℃, and 218℃ respectively, with the temperature gradient controlled within 7℃. After cooling, the insulated wire core is obtained, and the volume resistivity of the insulation layer is measured to be 1.6×10^16 Ω·cm.

[0066] Shielding unit fabrication: A tin-plated copper wire shielding layer is braided on the outside of the insulated core. The inner braiding pitch is 9 times the outer diameter of the braiding layer, and the outer braiding pitch is 11 times the outer diameter of the braiding layer. The braiding density is 93%, and the tin plating layer on the copper wire surface is 9μm thick. After braiding, a polyurethane corrosion-resistant passivation coating modified with 3% fluorocarbon resin is applied online with a coating thickness of 19μm. The coating is then cured in an 80℃ oven for 20min. The shielding effectiveness of the shielding layer at 100MHz is 66dB.

[0067] Preparation of the barrier protection unit: An aluminum-plastic composite tape and an acid-alkali modified water-blocking and corrosion-resistant composite tape are overlapped and wrapped around the outside of the shielding unit. The aluminum layer thickness of the aluminum-plastic composite tape is 0.08mm, the surface density of the acid-alkali modified water-blocking and corrosion-resistant composite tape is 160g / m², the wrapping overlap rate is 32%, the wrapping tension is controlled at 13N, and after the wrapping is completed, acid-alkali resistant hot melt adhesive is sprayed. After the hot melt adhesive is cured, the bonding strength test is 1.6N / mm.

[0068] Outer sheath unit preparation: 5% poly(perfluoroethylene) propylene blend modified crosslinked ETFE material was extruded onto the outside of the barrier protection unit using an extruder. The extrusion temperatures from the barrel to the die were set to 295℃, 305℃, 315℃, and 320℃ respectively. The outer sheath thickness was controlled at 2.5mm with a thickness deviation of ±0.06mm. After extrusion, the material was crosslinked by electron beam irradiation at a dose of 190kGy, and the crosslinking degree was tested to be 88%. Subsequently, the cable sample was placed in a gas-phase fluorination reactor, and a 20% concentration of fluorine-nitrogen mixed gas was introduced. The treatment temperature was 58℃, and the treatment time was 14min, resulting in an outer sheath with a surface fluorinated layer depth of 28μm. The surface fluorine content was tested to be 69%, and the surface energy was 16.8mN / m.

[0069] Interlayer bonding treatment: Acid and alkali resistant modified fluororubber adhesive is applied between every two layers of the structure with a coating thickness of 0.06 mm. It is cured at 100°C for 10 min. The interlayer peel strength test result is 1.1 N / mm. Finally, the solvent-resistant and corrosion-resistant cable sample of this embodiment is obtained.

[0070] Performance testing The samples in this embodiment were further immersed in 10% sulfuric acid and 10% sodium hydroxide for 30 days according to the general testing method, and the results were recorded in the subsequent data table. This embodiment optimizes the formula for acid and alkali corrosion environments, which can solve the defects of existing cables that are insufficient in acid and alkali resistance and cannot adapt to complex chemical corrosion scenarios.

[0071] Comparative example: Ordinary corrosion-resistant cable (existing technology) Sample preparation Conductor unit preparation: Take 56 high-purity oxygen-free copper wires with a diameter of 0.2 mm and strand them together using a stranding process. The stranding pitch ratio is 14 times. No corrosion-resistant sealant is used during the stranding process. Only ordinary talc powder is used for filling. The filling density is 85%, resulting in a conductor unit with a diameter of 1.8 mm and a conductor surface roundness of 90%.

[0072] Insulation protection unit preparation: A pure cross-linked polyethylene insulation layer is coated on the outside of the conductor unit using a common three-layer co-extrusion process. The inner semi-conductive buffer layer has a thickness of 0.5 mm, the middle pure cross-linked polyethylene main insulation layer has a thickness of 1.0 mm, and the outer semi-conductive shielding layer has a thickness of 0.3 mm. The co-extrusion temperature gradient is controlled within 15℃. After cooling, the insulated wire core is obtained. The volume resistivity of the insulation layer is measured to be 1.0×10^16 Ω·cm.

[0073] Shielding unit fabrication: A single-layer tinned copper wire shielding layer is braided on the outside of the insulated core. The braiding density is 85%, the tin-plated layer thickness on the copper wire surface is 5μm, and there is no additional passivation coating. The shielding effectiveness of the shielding layer at 100MHz is 50dB.

[0074] Preparation of the barrier protection unit: Only a single layer of ordinary polyester tape is wrapped around the outside of the shielding unit, with a wrapping overlap rate of 15% and a wrapping tension of 8N. No additional hot melt adhesive bonding treatment is used, and the bonding strength test is 0.3N / mm.

[0075] Outer sheath unit preparation: Ordinary polytetrafluoroethylene material is extruded onto the outside of the barrier and protection unit using an extruder at an extrusion temperature of 300℃. The outer sheath thickness is 2.0mm. There is no radiation crosslinking treatment or gas phase fluorination treatment. The surface fluorine content is 58%, the surface energy is 25mN / m, the tensile strength test is 12MPa, and the elongation at break test is 150%.

[0076] Interlayer treatment: No adhesive is applied between the structural layers, and the interlayer peel strength test is 0.2 N / mm, finally obtaining the ordinary corrosion-resistant cable sample of this comparative example.

[0077] Performance testing The comparative sample was subjected to full performance testing using the same testing method as the example, and the results were recorded in the subsequent data table as a comparison and verification of the defects of the prior art.

[0078] Core reaction molecular formula and explanation The core reactions in the crosslinking modification process of the outer sheath material are as follows: ; This reaction is a free radical crosslinking reaction under electron beam irradiation. The molecular chains of ethylene-tetrafluoroethylene copolymer generate free radicals under the action of high-energy electron beams, and C-C covalent crosslinking bonds are formed between the molecular chains, which transforms the material from thermoplastic to thermosetting. The density of the molecular network is significantly improved, reducing the diffusion channels of solvent molecules and effectively solving the defects of low crosslinking degree and easy swelling of existing polytetrafluoroethylene sheath materials.

[0079] The core reaction of the vapor phase fluorination treatment on the outer sheath surface is as follows: ; This reaction is a substitution reaction between fluorine gas and the molecular chains on the polymer surface, replacing the CH bonds on the outer sheath with CF bonds. The CF bond energy is as high as 485kJ / mol, with extremely strong chemical stability, which can resist the erosion of strong polar solvents, acids and alkalis, etc., effectively reducing the surface energy of the material, improving the solvent penetration resistance, and solving the defects of insufficient surface density and easy corrosion of existing sheath materials.

[0080] Table 1 Results of organic solvent immersion test This table presents the test results after immersion in a toluene / acetone mixed solvent for 30 days, directly reflecting the differences in solvent resistance of the materials. The volume change rate of the sheath in Examples 1-4 is less than 0.8%, significantly lower than the 5.7% of the comparative example, and the tensile strength retention rate is higher than 92%, indicating that crosslinking modification and fluorination treatment effectively improve the solvent resistance stability of the outer sheath. The insulation resistance retention rate of the examples is higher than 90%, and the shielding layer resistance change rate is lower than 8%, indicating that the multi-layer protective structure effectively prevents solvent penetration, solving the defects of existing technologies where solvents easily penetrate the sheath, leading to insulation failure and shielding layer corrosion. Example 3 exhibits the best performance, demonstrating the ultimate protection effect under high parameter levels; Example 4 is optimized for acid and alkaline environments, while still maintaining excellent solvent resistance, verifying the formulation's suitability.

[0081] Table 2 Results of neutral salt spray corrosion performance test after 1000 hours This table shows the test results after 1000 hours of neutral salt spray, reflecting the cable's resistance to salt spray corrosion. The sheaths of all embodiments showed no obvious appearance changes, the insulation resistance retention rate was higher than 88%, and the shielding layer resistance change rate was lower than 10%, which was far better than the test results of the comparative example, indicating that the multi-layer protective structure of this technical solution can effectively resist the electrochemical corrosion of chloride ions 2[5]. The interlayer bonding strength retention rate of the embodiments was higher than 85%, indicating that the interlayer bonding structure effectively prevented the salt spray medium from spreading along the interlayer gap, solving the defects of no interlayer sealing and easy corrosion penetration into the internal structure in the prior art 2. The indicators of embodiment 3 were the best, verifying the long-term salt spray resistance stability under high parameters.

[0082] Table 3 Performance test results after 30 days of acid and alkali immersion (Example 4 and comparative examples only) This table presents the test results after immersion in acid and alkali solutions for 30 days, reflecting the cable's resistance to acid and alkali corrosion. In Example 4, the sheath volume change rate in both acid and alkali media was less than 0.8%, the insulation resistance retention rate was higher than 89%, and the shielding layer resistance change rate was less than 7%. In contrast, the sheath in the comparative example showed severe swelling, a significant decrease in insulation performance, and severe corrosion of the shielding layer. This indicates that the acid and alkali resistant modified formula used in Example 4 effectively improved the cable's tolerance to acid and alkali media, solving the defect that existing cables cannot adapt to complex acid and alkali corrosion scenarios.

[0083] refer to Figure 2This study presents the differences in aging resistance performance of three types of cables under five typical corrosive environments. Ordinary PVC cables exhibit high mass loss rates under all corrosive environments, with significant aging phenomena, particularly under mixed corrosive and organic solvent environments. While conventional fluoroplastic cables show improved corrosion resistance compared to PVC cables, their aging rates remain high under strong solvent and mixed corrosive environments. The cable of this invention, benefiting from the synergistic protection of its modified ETFE outer sheath through vapor-phase fluorination and multi-layer barrier structure, demonstrates a significantly lower mass loss rate under all environments compared to the two comparative cables. This verifies the effectiveness of the structural design in improving solvent and corrosion resistance, directly showcasing the service advantages of this invention in complex corrosive scenarios.

[0084] refer to Figure 3 This study demonstrates the insulation performance degradation trends of three types of cables during long-term service in a mixed corrosive environment. Initially, the insulation performance of the three types of cables is basically the same. However, with increasing service time, the insulation resistance of ordinary PVC cables decreases at the fastest rate, with an insulation retention rate of only 15% after 48 months, which is insufficient to meet normal power transmission requirements. While the insulation degradation rate of conventional fluoroplastic cables is slower than that of PVC cables, the insulation retention rate falls below 60% after 36 months, posing a safety hazard. The cable of this invention, through the synergistic protection of conductor gap sealing, modified insulation layers, and multi-layer barrier structures, effectively slows down the penetration rate of corrosive media. Even after 48 months, the insulation resistance retention rate remains above 80%, significantly extending the effective service life of the cable in corrosive environments and reducing the overall cost of cable replacement and maintenance.

[0085] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A solvent-resistant and corrosion-resistant cable, characterized in that, From the inside out, it includes a conductor, an insulating layer, a sealing and corrosion-resistant layer, a shielding layer, a buffer layer, a barrier and protective layer, and an outer sheath. The conductor is made of multi-strand stranded tin-plated oxygen-free copper wire, with a nano-silane passivation film pre-coated on the surface of each copper wire, and the stranding gaps are filled with corrosion-resistant and alkali-free glass fiber rope, the surface of the filling rope is impregnated with a fluorine anti-corrosion coating. The insulating layer is made of cross-linked modified silicone rubber material, with a thickness of 0.8 mm to 1.5 mm, and the interface between the insulating layer and the conductor is coated with an organosilicon adhesive. The sealing and corrosion-resistant layer adopts a structure of overlapping and wrapping water-swellable waterproof tape and polytetrafluoroethylene film, with a total thickness of 0.12 mm to 0.2 mm. The shielding layer adopts a composite structure of tin-plated copper wire braiding and aluminum foil wrapping. The diameter of a single tin-plated copper wire is 0.1 mm to 0.2 mm. The surface of the shielding layer is coated with an oil-resistant and corrosion-resistant coating with a coating thickness of 5 μm to 10 μm. The buffer layer adopts a fluororubber modified polyimide film wrapping structure with a wrapping overlap rate of 25% to 35%, a film thickness of 0.05 mm to 0.1 mm, and 2 to 3 wrapping layers. The barrier protective layer adopts a metallized aramid fabric weaving structure with a weaving density of not less than 85%, and the metal plating layer is a nickel-chromium alloy with a plating thickness of 2μm to 5μm. The outer sheath is made of modified polytetrafluoroethylene composite material, with a thickness of 1.2 mm to 2.5 mm. The surface of the outer sheath is subjected to plasma fluorination treatment with a treatment depth of 100 nm to 300 nm.

2. The solvent-resistant and corrosion-resistant cable according to claim 1, characterized in that, The crosslinked modified silicone rubber material is prepared by radiation crosslinking of methyl vinyl silicone rubber, fumed silica, vinyltriethoxysilane, dicumyl peroxide, nano titanium dioxide, fluorosilane coupling agent, and anti-aging additive; wherein the mass fraction of methyl vinyl silicone rubber is 70 to 85 parts, the mass fraction of fumed silica is 15 to 25 parts, the mass fraction of vinyltriethoxysilane is 2 to 5 parts, the mass fraction of dicumyl peroxide is 0.5 to 1.5 parts, the mass fraction of nano titanium dioxide is 3 to 8 parts, the mass fraction of fluorosilane coupling agent is 1 to 3 parts, and the mass fraction of anti-aging additive is 0.5 to 2 parts. The anti-aging additive is obtained by mixing nickel dibutyldithiocarbamate and hindered phenolic antioxidants at a mass ratio of 1:1 to 2.

3. The solvent-resistant and corrosion-resistant cable according to claim 1, characterized in that, The modified polytetrafluoroethylene composite material is prepared by mixing polytetrafluoroethylene, perfluoropropyl vinyl ether, polyphenylene sulfide, nano boron nitride, graphite powder, polyimide micro powder and compatibilizer and then molding and sintering. The components are: polytetrafluoroethylene (PTFE) in the amount of 65 to 80 parts by mass, perfluoropropyl vinyl ether in the amount of 8 to 15 parts by mass, polyphenylene sulfide in the amount of 5 to 10 parts by mass, nano boron nitride in the amount of 2 to 6 parts by mass, graphite powder in the amount of 1 to 4 parts by mass, polyimide micro powder in the amount of 3 to 7 parts by mass, and compatibilizer in the amount of 1 to 3 parts by mass. The compatibilizer is maleic anhydride-grafted polytetrafluoroethylene. The volume change rate of the modified polytetrafluoroethylene composite material after immersion in a mixed organic solvent of xylene, acetone and ethyl acetate for 72 hours does not exceed 1%.

4. The solvent-resistant and corrosion-resistant cable according to claim 1, characterized in that, The tin-plated oxygen-free copper wires of the conductor undergo plasma surface activation treatment before stranding, with an activation power of 300W to 500W and a treatment time of 10s to 30s. The nano-silane passivation film was prepared by coating with a fluorinated silane hydrolysate. After coating, the drying temperature was 80℃ to 100℃ and the drying time was 5 min to 10 min. The fluorine anti-corrosion coating of the corrosion-resistant and alkali-free glass fiber rope is prepared by impregnation with perfluoropolyether coating. The curing temperature after impregnation is 120℃ to 150℃, the curing time is 20min to 30min, and the coating thickness is 10μm to 20μm.

5. The solvent-resistant and corrosion-resistant cable according to claim 1, characterized in that, The surface of the polytetrafluoroethylene film of the sealing and corrosion-resistant layer is corona treated. When the layers are stacked and wrapped, the polytetrafluoroethylene film is located on the outside. After wrapping, the layers are ironed and shaped by hot rollers at a temperature of 60°C to 80°C.

6. The solvent-resistant and corrosion-resistant cable according to claim 1, characterized in that, The tin-plated copper wire braiding pitch of the shielding layer is 10mm to 20mm, and the aluminum foil is double-sided tin-plated aluminum foil with a thickness of 0.03mm to 0.05mm; the oil-resistant and anti-corrosion coating is prepared by spraying epoxy resin-based oil-resistant coating, and the curing temperature after spraying is 100℃ to 120℃, and the curing time is 15min to 25min.

7. The solvent-resistant and corrosion-resistant cable according to claim 1, characterized in that, The fluororubber-modified polyimide film of the buffer layer is prepared by composite of polyimide substrate and fluororubber coating. The thickness of fluororubber coating is 20% to 30% of the total thickness of film. The tensile strength of film is not less than 150 MPa and the heat shrinkage rate at 150°C does not exceed 0.5%.

8. The solvent-resistant and corrosion-resistant cable according to claim 1, characterized in that, The metallized aramid fabric of the barrier protective layer has a basis weight of 80 g / m² to 120 g / m², and the nickel-chromium alloy plating has a nickel content of 70% to 80% and a chromium content of 20% to 30%. After weaving, the surface is coated with fluorine conformal paint with a coating thickness of 3 μm to 8 μm.

9. A method for preparing a solvent-resistant and corrosion-resistant cable, used to prepare the solvent-resistant and corrosion-resistant cable according to any one of claims 1 to 8, characterized in that, Includes the following steps: S1. Conductor preparation: Select oxygen-free copper wire with a tin-plated layer thickness of 1μm to 3μm, first perform plasma surface activation treatment with a power of 300W to 500W for 10s to 30s, then coat it with a fluorinated silane hydrolysate and dry it at 80℃ to 100℃ for 5min to 10min to form a nano-silane passivation film; then twist the multi-strand treated tin-plated oxygen-free copper wire with a pitch ratio of 12 to 18 to obtain the shaped conductor. S2. Insulation layer extrusion: Cross-linked modified silicone rubber material is coated onto the surface of the molded conductor through an extruder. Before extrusion, an organosilicon binder is uniformly coated on the surface of the molded conductor. After extrusion, electron beam radiation cross-linking is performed to obtain the insulated wire core. S3. Sealing and corrosion-resistant layer wrapping: After overlapping the water-swellable water-blocking tape with the polytetrafluoroethylene film, wrap it around the surface of the insulated wire core, with the polytetrafluoroethylene film on the outside; after wrapping, use hot roller ironing to shape it, and obtain the wire core with sealing and corrosion-resistant layer. S4. Shielding layer preparation: First, wrap double-sided tin-plated aluminum foil around the surface of the wire core with the sealing and corrosion-resistant layer, and then braid it with tin-plated copper wire with a single wire diameter of 0.1mm to 0.2mm; after the braiding is completed, spray epoxy resin-based oil-resistant coating on the surface of the shielding layer, and cure it at 100℃ to 120℃ to form an oil-resistant and corrosion-resistant coating, thus obtaining the wire core with the shielding layer. S5. Buffer layer wrapping: A fluororubber modified polyimide film is wrapped around the surface of the shielded core with an overlap rate of 25% to 35%. The number of wrapping layers is 2 to 3, and the wrapping tension is controlled at 3N to 8N. After wrapping, the core is heat-dried at 80℃ to 100℃ for 10 to 20 minutes to obtain a core with a buffer layer. S6. Barrier protective layer braiding: Metallized aramid cloth is braided on the surface of the core with buffer layer, with a braiding density of not less than 85% and a braiding tension controlled at 4N to 10N. After braiding, the surface is sprayed with fluorine three-proof paint and cured at room temperature for 24 hours to form a protective coating with a thickness of 3μm to 8μm, thus obtaining a core with barrier protective layer. S7. Outer Sheath Extrusion and Post-treatment: Modified polytetrafluoroethylene composite material is coated onto the surface of the wire core with a barrier protective layer using a plunger extruder. The extrusion temperature is controlled at 330℃ to 380℃. After extrusion, segmented sintering is performed at 200℃ to 250℃, 300℃ to 350℃, and 380℃ to 420℃, with each segment sintering for 10 to 20 minutes. After sintering, stepped cooling is adopted, with the cooling temperature decreasing to 250℃ to 300℃, 150℃ to 200℃, and room temperature, respectively. After cooling, the outer sheath surface is subjected to plasma fluorination treatment with a treatment power of 500W to 800W, a treatment time of 30s to 60s, and a treatment depth controlled at 100nm to 300nm, to obtain a solvent-resistant and corrosion-resistant cable.

10. The method for preparing the solvent-resistant and corrosion-resistant cable according to claim 9, characterized in that, In step S1, the preparation process of the fluorine anti-corrosion coating of the corrosion-resistant and alkali-free glass fiber rope is as follows: the alkali-free glass fiber rope is immersed in the perfluoropolyether coating for 10s to 20s, and after being taken out, it is cured at 120℃ to 150℃ for 20min to 30min. The coating thickness is controlled to be 10μm to 20μm, and the coating adhesion after curing is not lower than grade 0. In step S5, the preparation process of the fluororubber modified polyimide film is as follows: a fluororubber emulsion is uniformly coated on the surface of the polyimide film with a coating thickness of 10 μm to 30 μm. After coating, the film is vulcanized at 150°C to 180°C for 20 min to 30 min to obtain a composite film with a fluororubber coating thickness accounting for 20% to 30% of the total thickness and a tensile strength of not less than 150 MPa. After step S7 is completed, the finished cable is subjected to air tightness test, solvent immersion test and electrical performance test in sequence. The air tightness test pressure is 0.2MPa to 0.5MPa, the pressure holding time is 5min to 10min, and the pressure drop is not more than 0.02MPa to be qualified. The solvent immersion test uses a mixed medium of xylene, acetone, 10% hydrochloric acid and 10% sodium hydroxide. After immersion for 72h, the sheath volume change rate is not more than 1% to be qualified. The electrical performance test includes insulation resistance of not less than 100MΩ·km and power frequency withstand voltage of 2500V AC for 1min without breakdown.

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