High-conductivity and high-corrosion-resistance grounding cable

Abstract

The invention discloses a high-conductivity and high-corrosion-resistance grounding cable, and belongs to the technical field of power transmission. The preparation method comprises the steps of conductor pretreatment, coating slurry preparation, coating and post-treatment, wherein a copper-clad steel stranded wire is subjected to laser micro sand blasting to form a nanoscale concave-convex structure; the preparation method comprises the following steps: compounding a pH sensitive microcapsule synthesized by a re-emulsification-crosslinking method with polyaniline emulsion, and performing ultrasonic dispersion to prepare slurry; a functional layer is formed through repeated pulling-drying, and then residual stress is eliminated through vacuum drying and curing. The core advantages lie in that all technical characteristics have a synergistic effect: the binding force of the coating is improved by laser micro sand blasting, the continuous high conductivity is guaranteed by polyaniline, and the pH-sensitive microcapsule releases a corrosion inhibitor in an extreme acid-base environment to form a passive film so as to realize intelligent self-repairing. The cable has high binding force, stable conductivity and efficient corrosion resistance, the service reliability and the service life of the cable in a complex and severe environment are remarkably improved, and the cable has important application value.

Description

Technical Field

[0001] This invention belongs to the field of power transmission technology, specifically relating to a high-conductivity and high-corrosion-resistant grounding cable. Background Technology

[0002] With the increasing demands for safety and reliability in power systems, grounding cables, as key components ensuring the safety of electrical equipment and personnel, have seen their conductivity and corrosion resistance become crucial indicators. This is especially true in areas prone to acid rain and where soil pH fluctuates dramatically, where traditional grounding cables face significant challenges. Existing technologies present an irreconcilable contradiction between high conductivity and high corrosion resistance: pure copper conductors offer excellent conductivity, but their coatings are prone to hydrolysis and failure; copper-clad steel structures offer high mechanical strength but sacrifice conductivity and lack self-healing capabilities; while some technologies incorporating corrosion inhibitors suffer from low repair efficiency and unstable conductive networks due to the lack of a pH-responsive mechanism.

[0003] Patent application CN103354126A uses a grounding conductor made of an aluminum-magnesium-silicon-iron alloy (94% Al, 4.7% Mg, 0.8% Si, 0.45% Fe) with a resistivity not exceeding 0.03 Ω·mm. 2 The aluminum alloy conductor is coated with a conductive sheath composed of polyethylene, conductive carbon black, etc., aiming to balance conductivity and corrosion resistance. However, the intrinsic resistivity of the aluminum alloy conductor used in this solution is significantly higher than that of pure copper, which limits its application in high conductivity scenarios. More importantly, its conductive sheath is a static structure, which is difficult to suppress the corrosion process in an acid rain environment with pH=3.5. After the sheath is damaged, the conductor is prone to rapid deterioration, and its adaptability to dynamic pH change conditions is limited.

[0004] Existing typical solutions, such as pure copper conductors with epoxy coatings, suffer from increased porosity due to coating hydrolysis in acidic environments, resulting in a significant reduction in service life. While copper-clad steel with polyurethane systems improve mechanical strength, the corrosion current density surges under acidic conditions. Furthermore, technologies using pre-embedded corrosion inhibitors suffer from abnormal resistance fluctuations and low corrosion inhibition efficiency due to inhibitor agglomeration and lack of pH specificity, thus limiting their industrial applicability.

[0005] The above issues indicate that there is still room for improvement in terms of the upper limit of conductivity, dynamic adaptability to corrosive environments, and stability of conductive networks for current grounding cables. Summary of the Invention

[0006] One of the objectives of this invention is to provide a highly conductive and corrosion-resistant grounding cable, thereby solving the problem of deterioration in the conductivity of existing grounding cables in acid-base fluctuating environments.

[0007] The objective of this invention can be achieved through the following technical solutions: A high-conductivity, high-corrosion-resistant grounding cable is prepared by the following steps: S1. Conductor pretreatment: Take copper-clad steel stranded wire and perform laser micro-blasting to form a nanoscale concave-convex structure; S2. Coating slurry preparation: pH-sensitive microcapsules are added to polyaniline emulsion and ultrasonically treated to ensure uniform dispersion of the microcapsules; S3. Coating: The pretreated conductor is immersed in the coating slurry and pulled up. After being dried by hot air, the pulling-drying operation is repeated to form a pH-responsive self-healing functional layer. S4. Post-treatment: Vacuum drying and curing of the coated cable to eliminate residual stress and obtain a high-conductivity and high-corrosion-resistant grounding cable. The pH-sensitive microcapsules were synthesized via a complex emulsification-crosslinking method, with the specific steps as follows: A1. Dissolve acrylic acid and methyl methacrylate in anhydrous ethanol, add azobisisobutyronitrile initiator, remove oxygen by purging with nitrogen, and react at a constant temperature to obtain a copolymer prepolymer solution. A2. Add sodium molybdate aqueous solution dropwise to copolymer prepolymer and emulsify by high-speed shearing to form W / O / W type complex emulsion; A3. Add glutaraldehyde dropwise to the complex emulsion, stir and solidify to cause Schiff base crosslinking in the shell; A4. Collect the microcapsules by centrifugation, wash and vacuum dry to obtain pH-sensitive microcapsules.

[0008] S1 utilizes the synergistic advantages of high conductivity in the copper layer and high strength in the steel core; laser micro-blasting creates a nano-textured structure, primarily to increase the surface area and enhance the mechanical adhesion of subsequent coatings, preventing coating peeling. S2 polyaniline combines high conductivity with basic corrosion resistance, ensuring the coating does not affect grounding functionality; pH-sensitive microcapsules enable "environmentally responsive self-healing," compensating for protection shortcomings in extreme pH environments; ultrasonic treatment breaks up microcapsule aggregation, ensuring uniform coating performance. S3 pull coating allows for precise thickness control; repeated pull-drying gradually builds up thickness, eliminates pinholes and other defects, forming a dense, uniform, self-healing functional layer, ensuring long-term protection. S4 vacuum drying and curing eliminates residual stress in the coating, preventing cracking and peeling under subsequent operating conditions; the vacuum environment allows for low-temperature dehydration and degassing, improving coating density and ensuring operational stability.

[0009] The selected multi-emulsification-crosslinking method is used to precisely encapsulate the water-soluble corrosion inhibitor (sodium molybdate) to form a stable core-shell structure. The crosslinking reaction enhances the rigidity of the shell, preventing premature breakage, and allows for particle size control to adapt to coating requirements. In A1, acrylic acid provides pH responsiveness (carboxyl dissociation initiates swelling), while methyl methacrylate ensures shell rigidity; their copolymerization achieves a performance balance. The initiator triggers the polymerization reaction, and nitrogen purging removes free radical polymerization inhibitors, ensuring smooth polymerization. In A2, sodium molybdate acts as a corrosion inhibitor, forming a dense passivation film with iron ions to block corrosion. High-speed shear emulsification disperses the aqueous core material into tiny droplets, uniformly dispersing them in the oil phase to form a stable W / O / W multi-emulsion, laying the foundation for subsequent microcapsule molding. In A3, glutaraldehyde undergoes a Schiff base crosslinking reaction with the copolymer, enhancing the shell's mechanical strength and solvent resistance, controlling the swelling rate, and ensuring that the corrosion inhibitor is released only under extreme pH conditions. In A4, centrifugation rapidly separates the microcapsules, washing removes residual impurities to avoid affecting performance, and vacuum low-temperature drying removes moisture, preventing shell deformation or premature breakage and obtaining stable microcapsules.

[0010] Furthermore, in step A1, the weight ratio of acrylic acid, methyl methacrylate, azobisisobutyronitrile, and anhydrous ethanol is 50:(28-32):(0.75-1):(190-210); the nitrogen purging time is 15-20 min, the constant temperature reaction temperature is 53-57℃, and the reaction time is 5.5-6.5 h. The weight ratio of each material is to balance the pH responsiveness and rigidity of the shell and ensure complete polymerization; the nitrogen purging time and reaction temperature and humidity parameters are adapted to the initiator activity to ensure complete polymerization and uniform molecular weight of the product.

[0011] Furthermore, in step A2, the concentration of the sodium molybdate aqueous solution is 14-16 wt%, the oil-to-water volume ratio is 1:3, the high-speed shear emulsification speed is 12000-12500 rpm, and the emulsification time is 28-32 min. The sodium molybdate concentration is adapted to the corrosion inhibition requirements; too high a concentration can easily lead to crystallization and blockage, while too low a concentration provides insufficient protection. The oil-to-water ratio ensures uniform droplet dispersion. The high-speed shear parameters regulate the droplet size to ensure that the microcapsules meet the coating requirements.

[0012] Furthermore, in step A3, the volume ratio of glutaraldehyde to the prepolymer solution is (0.18-0.22) mL:10 mL, the curing temperature is 39-41℃, and the curing time is 2-2.5 h. The amount of glutaraldehyde used is balanced to control the degree of crosslinking, avoiding an overly brittle shell or insufficient crosslinking; the curing temperature and humidity are matched to the Schiff base reaction rate to ensure uniform and complete crosslinking.

[0013] Furthermore, in step A4, the centrifugation speed is 8000-9000 rpm, the centrifugation time is 15-20 min, deionized water is used for washing, and the washing is performed 3 times. The vacuum drying temperature is 40-45℃, and the drying time is 4-5 h. The centrifugation parameters ensure efficient separation of microcapsules without rupture; the deionized water washing avoids the introduction of impurities; and the drying parameters control the moisture removal rate to prevent damage to the shells.

[0014] Furthermore, the polyaniline emulsion is prepared by the following method: camphor sulfonic acid is dissolved in deionized water to prepare a solution, aniline monomer is added, and after cooling in an ice bath, ammonium persulfate aqueous solution is slowly added dropwise. After the addition is complete, the reaction is continued in an ice bath. The product is filtered, washed, and dried to obtain doped polyaniline powder. The polyaniline powder is dispersed in N-methylpyrrolidone and ultrasonically treated to obtain a homogeneous emulsion. Camphor sulfonic acid doping improves the conductivity and stability of polyaniline; the ice bath controls the exothermic polymerization rate to avoid product deterioration; ultrasonic dispersion breaks up polyaniline agglomerates, ensuring emulsion homogeneity and suitability for subsequent coating.

[0015] Furthermore, in the preparation of the polyaniline emulsion, the weight ratio of aniline, camphor sulfonic acid, and ammonium persulfate is 90:(240-280):(240-280); the concentration of the camphor sulfonic acid solution is 0.4-0.6 mol / L; the ice bath cooling temperature is 0-2℃; the dropping time of the ammonium persulfate aqueous solution is 30-40 min; after the dropping is completed, the ice bath reaction time continues for 4-5 h; in the preparation of the polyaniline emulsion, the product is washed using an alternating ethanol / water washing method, and dried under vacuum at 55-60℃. The weight ratio of materials ensures sufficient doping and complete polymerization; the concentration and temperature / humidity parameters are adapted to the reaction characteristics to ensure the conductivity and structural stability of the product. Alternating ethanol / water washing can remove both inorganic and organic impurities; the vacuum drying temperature is adapted to the product characteristics, quickly removing water and avoiding oxidation and deterioration.

[0016] Furthermore, during the preparation of the polyaniline emulsion, the solid content of the polyaniline powder in N-methylpyrrolidone is 10-12 wt%, the ultrasonic treatment power is 280-320 W, and the ultrasonic treatment time is 30-40 min. The solid content balances the emulsion viscosity and coating thickness; the ultrasonic parameters ensure sufficient dispersion and avoid agglomeration that could affect coating quality and conductivity.

[0017] Furthermore, in step S1, the diameter of the copper-clad steel stranded wire is 12.3-12.7 mm, the copper layer thickness is ≥0.35 mm, the tensile strength of the steel core is ≥1200 MPa, and the basic conductivity is ≥97% IACS. The parameters for laser micro-blasting also include: laser power 48-52 W, frequency 9.5-10.5 kHz, and linear speed 0.5 m / min. After treatment, the conductor surface roughness Ra=3.2±0.3 μm, the surface oxygen content ≤0.8 at%, and the formation of a regular micro-pit array with a depth of 5–8 μm and a spacing of 15–25 μm. The scanning speed for laser micro-blasting is 190-210 mm / s. The conductor parameters ensure conductivity and mechanical strength; the blasting parameters precisely control the micro-pit structure, improving coating adhesion while avoiding damage to the copper layer, thus ensuring conductivity.

[0018] Furthermore, in step S2, the ultrasonic treatment power is 280-320W, and the time is 14-16 minutes; the weight ratio of pH-sensitive microcapsules to polyaniline emulsion is (0.75-1):100. The ultrasonic parameters ensure uniform dispersion of the microcapsules; the material ratio ensures sufficient self-healing sites without affecting the conductivity and density of the coating.

[0019] Furthermore, in step S3, the lifting speed is 4.8-5.2 cm / s, the hot air drying temperature is 78-82℃, and the drying time is 28-32 min. The lifting-drying operation is repeated 3 times. In step S3, the total thickness of the pH-responsive self-healing functional layer is 140-160 μm. In step S4, the vacuum drying temperature is 55-60℃, and the time is 12-14 h. The lifting and drying parameters control the single coating thickness and curing effect; the number of repetitions ensures that the total thickness is adapted to the protection and conductivity requirements; the post-treatment parameters ensure that residual stress is fully eliminated, improving the stability of the coating.

[0020] The beneficial effects of this invention are: (1) This invention uses copper-clad steel stranded wire as the conductor core, which provides a high conductivity foundation through the surface copper while ensuring excellent mechanical strength. The conductor surface is treated with laser micro-blasting to form a rough surface with a nanoscale concave-convex structure and a regular micro-pit array, which not only greatly increases the specific surface area, but also creates mechanical anchoring points. Secondly, the pH-responsive self-healing functional layer of the cable outer layer is key. This functional layer uses oxidized polyaniline as the matrix, which has excellent conductivity and ensures smooth current transmission. The polyaniline prepared by chemical oxidation polymerization and camphor sulfonic acid doping has stable performance. When preparing the coating slurry, pH-sensitive microcapsules are added to the polyaniline emulsion at a specific volume fraction and ultrasonically treated to ensure that the microcapsules are monodisperse and uniformly distributed in the matrix, avoiding local aggregation.

[0021] (2) The coating process used in this invention adopts the dip-coating method. By controlling the dipping speed and drying temperature, and repeating the dipping-drying process three times, the thickness of the functional layer is precisely controlled and highly dense, effectively eliminating pinhole defects. Finally, the residual stress of the coating is eliminated through vacuum drying and curing treatment, which improves the long-term stability.

[0022] (3) The pH-sensitive microcapsules provided by this invention are specifically synthesized through a complex emulsification-crosslinking method. Their core working mechanism is intelligent response and active protection: when the pH value of the soil environment where the cable is located is abnormal (≤4.0 or ≥9.0), H… + or OH - The penetrating coating causes the carboxyl groups in the microcapsule shell to dissociate and rapidly absorb water, swelling and rupturing to release the sodium molybdate corrosion inhibitor from the core. The inhibitor migrates to the conductor surface and reacts with the generated Fe... 2+ The reaction produces dense FeMoO 4 The passivation film, with its high impedance, effectively blocks corrosion current. Simultaneously, the polyaniline matrix itself remains intact, maintaining high surface conductivity and ensuring stable grounding resistance.

[0023] (4) In summary, these technical features work together to achieve the three core advantages of the cable: extremely high bonding force between the conductor and the coating, continuous high conductivity guaranteed by the polyaniline matrix, and rapid and efficient self-repairing corrosion protection capability formed by microcapsule intelligent triggering in corrosive environments, thereby significantly improving the long-term service reliability and lifespan of the grounding cable in complex and harsh environments. Detailed Implementation

[0024] The specific embodiments of the present invention will be described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0025] Example 1

[0026] This embodiment provides a high-conductivity, high-corrosion-resistant grounding cable, which is prepared through the following steps: S1. Conductor pretreatment: Take a 12.5mm diameter copper-clad steel stranded wire and perform micro-blasting treatment using a laser with a power of 50W, a frequency of 10kHz, a scanning speed of 200mm / s, and a line speed of 0.5m / min to achieve a surface roughness Ra of 3.2μm.

[0027] S2. Synthesis of pH-sensitive microcapsules: 50 parts by weight of acrylic acid, 30 parts by weight of methyl methacrylate, 0.8 parts by weight of azobisisobutyronitrile, and 200 parts by weight of anhydrous ethanol were reacted at 55℃ for 6 hours to obtain a prepolymer. A 15wt% sodium molybdate aqueous solution was added at an oil-to-water volume ratio of 1:3, and emulsified at 12000 rpm for 30 minutes to form a double emulsion. Glutaraldehyde (0.2 mL / 10 mL of prepolymer) was added, and the mixture was cured at 40℃ for 2 hours. After centrifugation, washing with water, and vacuum drying at 40℃ for 4 hours, pH-sensitive microcapsules were obtained.

[0028] S3. Preparation of polyaniline emulsion: Camphor sulfonic acid was prepared into a 0.5 mol / L solution, and aniline:camphor sulfonic acid:ammonium persulfate = 90:250:250 (parts by weight) was reacted in an ice bath at 0-2℃ for 4 h. After washing and vacuum drying at 60℃, the product was dispersed in N-methylpyrrolidone with a solid content of 12 wt%, and sonicated at 300 W for 30 min to obtain an emulsion.

[0029] S4. Coating Preparation: Microcapsules were added to polyaniline emulsion at 0.8 wt% (relative to polyaniline powder), and ultrasonicated at 300 W for 15 min to obtain a slurry. The pretreated conductor was immersed and pulled at a speed of 5 cm / s, and dried with hot air at 82℃ for 30 min, repeated 3 times. Finally, it was cured by vacuum drying at 60℃ for 12 h to obtain a high-conductivity and high-corrosion-resistant grounding cable.

[0030] Example 2

[0031] Compared with Example 1, the difference in this embodiment is that the weight ratio of acrylic acid to methyl methacrylate in the microcapsule synthesis is changed from 50:30 to 50:28, the reaction time is changed to 5.5h, the amount of camphor sulfonic acid and ammonium persulfate in the polyaniline emulsion is changed to 240 parts, the solid content is changed to 10wt%, the coating pulling speed is changed to 4.8cm / s, the drying temperature is changed to 78℃, and the curing time is changed to 14h.

[0032] The remaining raw materials and preparation process are the same as in Example 1.

[0033] Example 3

[0034] Compared with Example 1, the difference in this embodiment is that the weight ratio of acrylic acid to methyl methacrylate in the microcapsule synthesis is changed from 50:30 to 50:32, and the emulsification time is changed to 32 min; the ammonium persulfate addition time in the preparation of polyaniline is changed to 40 min, and the ultrasonic power is changed to 280 W and the time is 40 min; the ultrasonic power of the coating slurry is changed to 280 W and the time is 16 min.

[0035] The remaining raw materials and preparation process are the same as in Example 1.

[0036] Example 4

[0037] Compared with Example 1, the difference in this embodiment is that the power of the conductor laser micro-blasting is changed to 52W and the frequency is changed to 10.5kHz; the concentration of sodium molybdate solution in the microcapsule synthesis is changed to 14wt% and the amount of glutaraldehyde is changed to 0.18mL / 10mL prepolymer; the total coating thickness is controlled to 140μm.

[0038] The remaining raw materials and preparation process are the same as in Example 1.

[0039] Example 5

[0040] Compared with Example 1, the difference in this embodiment is that the power of the conductor laser micro-blasting is changed to 48W and the frequency is changed to 9.5kHz; the concentration of sodium molybdate solution in the microcapsule synthesis is changed to 16wt% and the curing time is changed to 2.5h; the drying temperature of polyaniline is changed to 55℃; and the curing temperature of the coating is changed to 55℃ and the time is changed to 13h.

[0041] The remaining raw materials and preparation process are the same as in Example 1.

[0042] Example 6

[0043] Compared with Example 1, the difference in this embodiment is that the conductor diameter is changed to 12.3 mm; the centrifugation speed in microcapsule synthesis is changed to 9000 rpm and the drying temperature is changed to 45℃; the amount of microcapsules added in the coating slurry is changed to 0.75 wt%; and the total thickness of the functional layer is controlled to 160 μm.

[0044] The remaining raw materials and preparation process are the same as in Example 1.

[0045] Comparative Example 1

[0046] The difference between this comparative example and Example 1 is that pH-sensitive microcapsules are not added in step S2 of the coating slurry preparation. Specifically, polyaniline emulsion is used directly as the coating slurry.

[0047] The remaining raw materials and preparation process are the same as in Example 1.

[0048] Comparative Example 2

[0049] The difference between this comparative example and Example 1 is that in step A2, the "15wt% sodium molybdate aqueous solution" is replaced with "an equal volume of deionized water" in the microcapsule synthesis. The specific implementation steps are as follows: prepare microcapsules with water as the core.

[0050] The remaining raw materials and preparation process are the same as in Example 1.

[0051] Comparative Example 3

[0052] The difference between this comparative example and Example 1 is that in step S2, "polyaniline emulsion" is replaced with "an equal volume of ordinary epoxy insulating varnish (commercially available)". The specific implementation steps are as follows: use epoxy varnish as a matrix to prepare a coating slurry containing microcapsules.

[0053] The remaining raw materials and preparation process are the same as in Example 1.

[0054] Comparative Example 4

[0055] The difference between this comparative example and Example 1 is that the laser micro-blasting treatment in step S1 is omitted. The specific implementation steps are as follows: the conductor is directly coated after being cleaned with acetone only.

[0056] The remaining raw materials and preparation process are the same as in Example 1.

[0057] Comparative Example 5

[0058] The difference between this comparative example and Example 1 is that in step A1, the weight ratio of acrylic acid to methyl methacrylate is changed from 50:30 to 50:50 in the microcapsule synthesis.

[0059] The remaining raw materials and preparation process are the same as in Example 1.

[0060] Comparative Example 6

[0061] Compared with Example 1, the difference in this comparative example is that in step S3, coating application, "repeated the lifting-drying operation 3 times" is changed to "only perform the lifting-drying operation once".

[0062] The remaining raw materials and preparation process are the same as in Example 1.

[0063] Performance testing

[0064] The performance of the cable samples prepared in Examples 1-6 and Comparative Examples 1-6 was tested: 1. Initial grounding resistance: Measured in a standard soil model box in accordance with GB / T 21431-2023.

[0065] 2. Salt spray corrosion resistance: Refer to GB / T 10125-2021, conduct a 240h neutral salt spray test, and measure the change rate of grounding resistance after the test.

[0066] 3. Coating adhesion: Refer to GB / T 2792-2014 and conduct a 90° peel test to test the peel strength.

[0067] 4. pH response self-healing ability: Immerse a section of the sample in an H2SO4 solution with pH=3.5 for 2 hours, remove it, clean and dry it, and measure its grounding resistance recovery rate (the ratio of the resistance in the soil model under the same conditions before immersion).

[0068] The results are shown in Table 1: Table 1

[0069] As shown in Table 1, the performance test data of each embodiment of the present invention are comprehensive and excellent, fully verifying the effectiveness of the technical solution. All sample examples exhibited extremely low initial grounding resistance, proving that the combination of the polyaniline conductive matrix and the copper-clad steel conductor perfectly maintains the basic conductivity of the cable. After 240 hours of rigorous salt spray corrosion, the increase in grounding resistance was controlled within 5%, and the coating peel strength reached approximately 16 N / mm, demonstrating excellent long-term corrosion resistance and interfacial bonding stability. Most importantly, under extreme conditions simulating soil acidification (immersion in a pH=3.5 solution for 2 hours), the grounding resistance recovery rate of all embodiments exceeded 97.5%, reaching a maximum of 98.5%. This directly proves that the intelligent response and efficient repair mechanism of the pH-sensitive microcapsules played a decisive role: the microcapsules can quickly sense the corrosive environment, accurately release the sodium molybdate corrosion inhibitor, and form a protective passivation film on the conductor surface, thereby actively inhibiting corrosion development in its early stages and achieving "self-repair" of the conductivity function.

[0070] The corrosion performance of Comparative Example 1 (without microcapsules) and Comparative Example 2 (microcapsules without corrosion inhibitors) was severely degraded (resistance recovery rate only ~65%, resistance surged by over 22% after salt spray), confirming that both "intelligent response" and "effective repair" are indispensable, and a simple physical barrier cannot achieve active protection. Comparative Example 3 (replaced with insulating epoxy paint) completely lost its conductivity, highlighting that using conductive polyaniline as the functional layer matrix is ​​the fundamental prerequisite for achieving the coexistence of "high conductivity" and "functional coating". The peel strength of Comparative Example 4 (omitting laser microblasting treatment) dropped sharply by about 50%, resulting in a significant decrease in its protective performance, highlighting the fundamental role of the laser-constructed micro-nano rough interface in ensuring long-term firm adhesion of the functional layer and preventing early failure. The repair efficiency of Comparative Example 5 (changing the monomer ratio of the microcapsule shell) was significantly reduced, indicating that the specific ratio of acrylic acid to methyl methacrylate is the key design for achieving rapid pH response, and no arbitrary copolymer can achieve the same effect. The performance degradation of Comparative Example 6 (coating too thin) demonstrates that building a moderately thick and dense coating through multiple coats is a necessary process to ensure long-term barrier effect and repair agent reserves.

[0071] The above-disclosed embodiments are merely a few specific examples of the present invention. However, the embodiments of the present invention are not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. A high-conductivity, high-corrosion-resistant grounding cable, characterized in that, The method for preparing the high-conductivity, high-corrosion-resistant grounding cable includes the following steps: S1. Conductor pretreatment: Take copper-clad steel stranded wire and perform laser micro-blasting to form a nanoscale concave-convex structure; S2. Coating slurry preparation: pH-sensitive microcapsules are added to polyaniline emulsion and ultrasonically treated to ensure uniform dispersion of the microcapsules; S3. Coating: The pretreated conductor is immersed in the coating slurry and pulled up. After being dried by hot air, the pulling-drying operation is repeated to form a pH-responsive self-healing functional layer. S4. Post-treatment: Vacuum drying and curing of the coated cable to eliminate residual stress and obtain a high-conductivity and high-corrosion-resistant grounding cable. The pH-sensitive microcapsules were synthesized via a complex emulsification-crosslinking method, with the specific steps as follows: A1. Dissolve acrylic acid and methyl methacrylate in anhydrous ethanol, add azobisisobutyronitrile initiator, remove oxygen by purging with nitrogen, and react at a constant temperature to obtain a copolymer prepolymer solution. A2. Add sodium molybdate aqueous solution dropwise to copolymer prepolymer and emulsify by high-speed shearing to form W / O / W type complex emulsion; A3. Add glutaraldehyde dropwise to the complex emulsion, stir and solidify to cause Schiff base crosslinking in the shell; A4. Collect the microcapsules by centrifugation, wash and vacuum dry to obtain pH-sensitive microcapsules.

2. The high conductivity and high corrosion resistance grounding cable according to claim 1, characterized in that, In step A1, the weight ratio of acrylic acid, methyl methacrylate, azobisisobutyronitrile and anhydrous ethanol is 50:(28-32):(0.75-1):(190-210); the nitrogen purging time for deoxygenation is 15-20 min, the constant temperature reaction temperature is 53-57℃, and the reaction time is 5.5-6.5 h.

3. The high conductivity and high corrosion resistance grounding cable according to claim 1, characterized in that, In step A2, the concentration of the sodium molybdate aqueous solution is 14-16 wt%, the oil-water volume ratio is 1:3, the high-speed shear emulsification speed is 12000-12500 rpm, and the emulsification time is 28-32 min.

4. The high conductivity and high corrosion resistance grounding cable according to claim 1, characterized in that, In step A3, the volume ratio of glutaraldehyde to prepolymer solution is (0.18-0.22) mL:10 mL, the stirring and curing temperature is 39-41℃, and the curing time is 2-2.5 h.

5. A high-conductivity, high-corrosion-resistant grounding cable according to claim 1, characterized in that, In step A4, the centrifugation speed is 8000-9000 rpm, the centrifugation time is 15-20 min, deionized water is used for washing, the washing is performed 3 times, the vacuum drying temperature is 40-45℃, and the drying time is 4-5 h.

6. The high conductivity and high corrosion resistance grounding cable according to claim 1, characterized in that, The polyaniline emulsion is prepared by the following method: camphor sulfonic acid is dissolved in deionized water to prepare a solution, aniline monomer is added, and after cooling in an ice bath, ammonium persulfate aqueous solution is slowly added dropwise. After the addition is completed, the reaction is continued in an ice bath. The product is filtered, washed, and dried to obtain doped polyaniline powder. The polyaniline powder is dispersed in N-methylpyrrolidone and ultrasonically treated to obtain a uniform emulsion.

7. A high-conductivity, high-corrosion-resistant grounding cable according to claim 6, characterized in that, In the preparation of polyaniline emulsion, the weight ratio of aniline, camphor sulfonic acid and ammonium persulfate is 90:(240-280):(240-280); the concentration of camphor sulfonic acid solution is 0.4-0.6 mol / L; the ice bath cooling temperature is 0-2℃; the dropping time of ammonium persulfate aqueous solution is 30-40 min; after dropping, the ice bath reaction time is continued for 4-5 h; in the preparation of polyaniline emulsion, the product is washed by alternating ethanol / water washing, and the drying is vacuum drying at 55-60℃.

8. A high-conductivity, high-corrosion-resistant grounding cable according to claim 6, characterized in that, In the preparation of polyaniline emulsion, the solid content of polyaniline powder in N-methylpyrrolidone is 10-12wt%, the ultrasonic treatment power is 280-320W, and the ultrasonic treatment time is 30-40min.

9. A high-conductivity, high-corrosion-resistant grounding cable according to claim 1, characterized in that, In step S1, the diameter of the copper-clad steel stranded wire is 12.3-12.7 mm, the copper layer thickness is ≥0.35 mm, the tensile strength of the steel core is ≥1200 MPa, and the basic conductivity is ≥97% IACS. The parameters of the laser micro-blasting treatment also include: laser power 48-52 W, frequency 9.5-10.5 kHz, line speed 0.5 m / min, the surface roughness of the conductor after treatment Ra=3.2±0.3 μm, the surface oxygen content ≤0.8 at%, and the formation of a regular micro-pit array with a depth of 5–8 μm and a spacing of 15–25 μm. The scanning speed of the laser micro-blasting treatment is 190-210 mm / s.

10. A high-conductivity, high-corrosion-resistant grounding cable according to claim 1, characterized in that, In step S2, the ultrasonic treatment power is 280-320W and the time is 14-16min; the weight ratio of pH-sensitive microcapsules to polyaniline emulsion is (0.75-1):

100. In step S3, the lifting speed is 4.8-5.2 cm / s, the hot air drying temperature is 78-82℃, the drying time is 28-32 min, and the lifting-drying operation is repeated 3 times; in step S3, the total thickness of the pH-responsive self-healing functional layer is 140-160 μm; in step S4, the vacuum drying temperature is 55-60℃, and the time is 12-14 h.

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