High barrier corrosion resistant aerial cable

Abstract

The application relates to the technical field of cables and discloses a high-barrier corrosion-resistant overhead cable. The high-barrier corrosion-resistant overhead cable comprises, from inside to outside, a conductor, a shielding layer and an insulation layer. The insulation layer comprises the following components by weight: 60-80 parts of high-density polyethylene, 25-35 parts of polymethyl methacrylate, 8-12 parts of modified porous kaolin, 15-25 parts of ethylene-vinyl acetate copolymer, 3-6 parts of a compatilizer, 0.5-2 parts of an antioxidant, 15-25 parts of a flame retardant and 0.5-1.5 parts of a lubricant. The modified porous kaolin is modified by acid etching, silane coupling agent and maleic anhydride grafted polymethyl methacrylate in sequence. The high-barrier corrosion-resistant overhead cable has improved insulation layer barrier performance, effectively hinders the penetration of corrosion medium, improves the agglomeration problem of traditional inorganic fillers, uniformly disperses the modified kaolin, improves the material toughness and is suitable for complex environments.

Description

Technical Field

[0001] This invention relates to the field of cable technology, and more specifically, to a high-barrier, corrosion-resistant overhead cable. Background Technology

[0002] High-barrier, corrosion-resistant overhead cables are specifically designed for power transmission in corrosive environments. They typically consist of key components such as conductors, shielding layers, and insulation layers. The insulation layer, as the core protective layer, directly determines the cable's corrosion resistance, electrical insulation performance, and mechanical properties. The insulation layer is usually composed of a composite of various polymer materials and inorganic fillers.

[0003] In complex natural environments, overhead cables inevitably come into contact with various corrosive media and are subjected to complex external forces. This necessitates that the insulation material possesses excellent toughness and corrosion resistance, capable of undergoing appropriate deformation without cracking under external forces to adapt to complex operating environments. Furthermore, the insulation layer of high-barrier corrosion-resistant overhead cables is typically composed of multiple polymer materials, and the interfacial bonding strength between different polymers plays a crucial role in the overall performance of the insulation layer. In existing cable manufacturing processes, due to a lack of effective interface optimization strategies, the interfacial bonding between different polymers is often suboptimal. Significant phase separation occurs at the interface, leading to poor stress transmission, stress concentration, and reduced mechanical properties of the material. Simultaneously, poor interfacial bonding also affects the electrical properties of the insulation layer, increasing interfacial resistance, causing localized overheating, and accelerating material aging and damage. Moreover, in the presence of corrosive media, weak points at the interface are more likely to become channels for corrosive media penetration, further reducing the cable's corrosion resistance and shortening its service life. To address these technical problems, this invention proposes a novel high-barrier corrosion-resistant overhead cable. Summary of the Invention

[0004] This invention proposes a high-barrier, corrosion-resistant overhead cable, which aims to achieve the synergistic effect of physical barrier of porous filler, chemical bonding between filler and matrix, and interfacial compatibilization between polymer matrix.

[0005] The technical solution of the present invention is as follows: In a first aspect, the present invention proposes a high-barrier, corrosion-resistant overhead cable, comprising, from the inside out, a conductor, a shielding layer, and an insulation layer. The insulation layer comprises the following raw materials in parts by weight: 60-80 parts of high-density polyethylene, 25-35 parts of polymethyl methacrylate, 8-12 parts of modified porous kaolin, 15-25 parts of ethylene-vinyl acetate copolymer, 3-6 parts of compatibilizer, 0.5-2 parts of antioxidant, 15-25 parts of flame retardant, and 0.5-1.5 parts of lubricant. The modified porous kaolin is obtained by acid etching to create pores and then sequentially modified by grafting polymethyl methacrylate with a silane coupling agent and maleic anhydride.

[0006] As a further technical solution, the preparation method of the modified porous kaolin includes: (1) Acid etching to create pores: Kaolin is dispersed in hydrochloric acid aqueous solution and stirred at 60~80℃ for 4~8h. After filtration, washing and drying, acid-etched kaolin is obtained. (2) First modification: Disperse acid-etched kaolin in anhydrous ethanol, add silane coupling agent, reflux reaction at 60~80℃ for 6~10h, filter, wash and dry to obtain aminosilanized porous kaolin; (3) Second modification: Aminosilanized porous kaolin is dispersed in toluene, maleic anhydride-grafted polymethyl methacrylate is added, and the mixture is reacted at 80~100℃ for 8~12h. After filtration, washing and drying, modified porous kaolin is obtained.

[0007] As a further technical solution, the mass fraction of the hydrochloric acid aqueous solution is 10-20%, and the mass ratio of kaolin to hydrochloric acid aqueous solution is 1:5-1:10.

[0008] As a further technical solution, the silane coupling agent is KH550; and the mass ratio of the silane coupling agent to the acid-etched kaolin is 1:100 to 5:100.

[0009] In this invention, KH550 was selected as the silane coupling agent. Compared with other silane coupling agents such as KH560 (containing epoxy groups) and KH570 (containing carbon-carbon double bonds), the terminal amino group of KH550 has unique reactivity. The maleic anhydride groups in maleic anhydride-grafted polymethyl methacrylate readily undergo ring-opening amidation with the terminal amino group of KH550 under heating conditions. This reaction can truly achieve the purpose of grafting the polymer onto the kaolin surface, forming a stable chemical bond. In contrast, the epoxy groups of KH560 have lower reactivity with the hydroxyl groups on the kaolin surface, and the chemical compatibility between the epoxy groups and the subsequently grafted MAH-g-PMMA is poor, making it difficult to form a stable chemical bond. Although KH570 has a certain degree of reactivity due to its double bond structure and better compatibility with maleic anhydride-grafted polymethyl methacrylate than KH560, its amidation reaction efficiency with the amino and anhydride groups of KH550 is still lower. Therefore, KH550 silane modification can more effectively improve the interfacial bonding between kaolin and the polymer matrix, laying the foundation for subsequent modification and performance improvement.

[0010] As a further technical solution, the mass ratio of maleic anhydride-grafted polymethyl methacrylate to silanized porous kaolin is 1:3 to 1:6.

[0011] As a further technical solution, the compatibilizer is maleic anhydride-grafted polyethylene.

[0012] As a further technical solution, the antioxidant is a mixture of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1 to 1:2.

[0013] As a further technical solution, the flame retardant is a mixture of decabromodiphenyl ethane and antimony trioxide in a mass ratio of 2:1 to 3:1.

[0014] As a further technical solution, the lubricant is zinc stearate or polyethylene wax.

[0015] As a further technical solution, the preparation steps of the high-barrier corrosion-resistant overhead cable include: S1, covering the outer side of the conductor with shielding material to obtain a semi-finished product; S2, weighing the raw materials of each component of the insulation layer according to the weight, mixing them evenly, and then melting and granulating them through a twin-screw extruder to obtain an insulating material; S3, extruding the insulating material through an extruder to cover the outer side of the semi-finished product to form an insulation layer, thereby obtaining a high-barrier corrosion-resistant overhead cable.

[0016] The working principle and beneficial effects of this invention are as follows: In this invention, hydrochloric acid selectively etches the aluminum-oxygen octahedral layer in kaolin during the acid etching pore-forming step, constructing a nanoscale mesoporous structure on the surface of the kaolin sheets. This nanoscale mesoporous structure significantly increases the specific surface area of ​​the kaolin, which in turn means a substantial increase in the number of surface active sites. This provides more reaction sites for subsequent modification treatments, facilitating the full execution of these reactions. More importantly, the porous structure plays a unique role in enhancing the insulation layer's performance. When corrosive media attempt to penetrate the insulation layer, the porous structure makes its penetration path tortuous and complex, prolonging the path and effectively hindering rapid penetration. This significantly improves the barrier properties of the insulation layer, providing a fundamental guarantee for the cable's corrosion resistance.

[0017] In this invention, maleic anhydride-grafted polymethyl methacrylate (PMMA-g-MAH) undergoes a grafting reaction with the surface of KH550-modified kaolin, forming a layer of PMMA on the kaolin surface. Firstly, PMMA itself is a polymer with excellent weather resistance, and its grafted layer exhibits good compatibility with the PMMA component in the matrix. This compatibility allows the modified kaolin to be uniformly dispersed in the insulation matrix, avoiding the performance degradation problem caused by agglomeration of traditional inorganic fillers. Traditional inorganic fillers are prone to agglomeration in polymer matrices, forming defective regions and reducing the overall performance of the material, while uniformly dispersed modified kaolin does not exhibit this phenomenon. Secondly, the PMMA grafted layer forms chemically bonded "molecular bridges" between the filler and the PMMA matrix. When the material is subjected to external forces, it can more effectively transfer stress from the matrix to the rigid filler, achieving reinforcement and toughening. This allows the cable insulation layer to possess both good corrosion resistance and good mechanical properties.

[0018] This invention constructs a multi-level interface optimization system. First, a PMMA grafted layer on the filler surface achieves good compatibility between the filler and the PMMA matrix. Second, maleic anhydride-grafted polyethylene is added as a compatibilizer. The maleic anhydride groups in its molecular chain can interact with the ester groups of PMMA, while the polyethylene segments have excellent compatibility with the high-density polyethylene (HDPE) matrix. This acts as a "compensator" between the two incompatible polymers, HDPE and PMMA, significantly reducing interfacial tension, inhibiting phase separation, and making the interfacial bonding between the two phases stronger. It also ensures that the synergistic effect among all components in the composite material is fully utilized, resulting in excellent comprehensive performance of the cable insulation layer in terms of mechanical properties, electrical insulation properties, corrosion resistance, and flame retardancy. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0020] It should be noted that the high-density polyethylene used in this invention was purchased from Dushanzi Petrochemical, with the grade DMDA-8008 and a melt flow index of 7.5 g / 10 min; The polymethyl methacrylate was purchased from Guanhe Plastics Technology (Shanghai) Co., Ltd., model number LGHP202; The ethylene-vinyl acetate copolymer was purchased from Dongguan Bohao Plastic Raw Materials Co., Ltd., and its grade was P1403. Maleic anhydride-grafted polyethylene was purchased from Nanjing Sutai Polymer Technology Co., Ltd., model PE-12LL. The kaolin is model SX-90A, with a D50 of 0.9μm; In this invention, the preparation method of maleic anhydride-grafted polymethyl methacrylate is as follows: First, 100g of polymethyl methacrylate (PMMA) base material was dried in an 80℃ forced-air drying oven for 5 hours to remove moisture. Then, 1.5g of initiator benzoyl peroxide, 5.0g of graft monomer maleic anhydride, and 2.0g of comonomer methyl methacrylate were dissolved in 28.0g of xylene and stirred until completely dissolved to prepare a mixed active solution. The dried PMMA was placed in a high-speed mixer, and under low-speed stirring, the prepared mixed active solution was evenly sprayed onto the surface of the PMMA. The mixture was then sealed and allowed to swell for 30 minutes. The swollen mixture was transferred to a Banbury mixer, and the mixer was started. Under a nitrogen protective atmosphere, the system temperature was rapidly raised to 120℃, and the rotor speed was set to 60 rpm. The mixture was kneaded and reacted under these constant temperature conditions for 15 minutes. After the reaction, the material was removed while hot, cooled to room temperature, and then pulverized into granules to obtain a crude PMMA-g-MAH product. 10.0g of this crude product was weighed. The pulverized crude PMMA-g-MAH product was wrapped in filter paper and placed in a Soxhlet extractor. Acetone was used as the extraction solvent, and extraction was carried out continuously for 24 hours under reflux conditions. After extraction, the product was removed and dried in a vacuum drying oven at 60°C until constant weight, thus obtaining purified PMMA-g-MAH.

[0021] Example 1 This embodiment provides a high-barrier, corrosion-resistant overhead cable, which comprises, from the inside out, a copper conductor, a shielding layer, and an insulation layer. The insulation layer comprises the following raw materials in parts by weight: 70 parts high-density polyethylene, 30 parts polymethyl methacrylate, 10 parts modified porous kaolin, 20 parts ethylene-vinyl acetate copolymer, 5 parts maleic anhydride-grafted polyethylene, 1 part a mixture of antioxidant 1010 and antioxidant 168 (mass ratio 1:1), 20 parts a mixture of decabromodiphenyl ethane and antimony trioxide (mass ratio 2:1), and 1 part zinc stearate. In this embodiment, the preparation steps of the modified porous kaolin are as follows: (1) Disperse 100g of kaolin in 800g of 15% hydrochloric acid aqueous solution, stir at 70℃ for 6h, filter, wash with deionized water until neutral, and dry at 100℃ for 12h to obtain acid-etched kaolin. (2) Disperse 80g of acid-etched kaolin in 500mL of anhydrous ethanol, add 2.4g of silane coupling agent KH550 (mass ratio of acid-etched kaolin to 3:100), reflux at 70℃ for 8h, filter, wash three times with anhydrous ethanol, and vacuum dry at 80℃ for 10h to obtain aminosilanized porous kaolin; (3) Disperse 50g of aminosilanized porous kaolin in 300mL of toluene, add 12g of maleic anhydride-grafted polymethyl methacrylate (mass ratio of maleic anhydride to silanized porous kaolin is 1:4.2), react at 90℃ for 10h, filter, wash three times with toluene, and vacuum dry at 80℃ for 12h to obtain modified porous kaolin; In this embodiment, the preparation steps of the high-barrier corrosion-resistant overhead cable include: S1. Cover the outside of the copper conductor with a semi-conductive shielding material to obtain a semi-finished product; S2. Weigh the raw materials of each component of the insulation layer according to the weight, mix them evenly, and then melt-blend and granulate them at 180°C using a twin-screw extruder to obtain the insulation material; S3. The insulating material is extruded onto the outside of the semi-finished product through an extruder to form an insulating layer, thereby obtaining a high-barrier, corrosion-resistant overhead cable.

[0022] Example 2 This embodiment provides a high-barrier, corrosion-resistant overhead cable, which comprises, from the inside out, a copper conductor, a shielding layer, and an insulation layer. The insulation layer comprises the following raw materials in parts by weight: 65 parts high-density polyethylene, 28 parts polymethyl methacrylate, 8 parts modified porous kaolin, 18 parts ethylene-vinyl acetate copolymer, 4 parts maleic anhydride-grafted polyethylene, 1.2 parts a mixture of antioxidants 1010 and 168 (mass ratio 1:1.5), 15 parts a mixture of decabromodiphenyl ethane and antimony trioxide (mass ratio 2.5:1), and 0.8 parts zinc stearate. In this embodiment, the preparation steps of the modified porous kaolin are as follows: (1) Disperse 100g of kaolin in 600g of 20% hydrochloric acid aqueous solution, stir at 60℃ for 8h, filter, wash and dry to obtain acid-etched kaolin; (2) Disperse 80g of acid-etched kaolin in 500mL of anhydrous ethanol, add 0.8g of silane coupling agent KH550 (mass ratio of acid-etched kaolin to 1:100), reflux at 60℃ for 10h, filter, wash and dry to obtain aminosilanized porous kaolin; (3) Disperse 50g of aminosilanized porous kaolin in 300mL of toluene, add 10g of maleic anhydride-grafted polymethyl methacrylate (mass ratio of maleic anhydride to silanized porous kaolin is 1:5), react at 80℃ for 12h, filter, wash and dry to obtain modified porous kaolin.

[0023] In this embodiment, the preparation steps of the high-barrier corrosion-resistant overhead cable include: S1. Cover the outside of the copper conductor with a semi-conductive shielding material to obtain a semi-finished product; S2. Weigh the raw materials of each component of the insulation layer according to the weight, mix them evenly, and then melt-blend and granulate them at 180°C using a twin-screw extruder to obtain the insulation material; S3. The insulating material is extruded onto the outside of the semi-finished product through an extruder to form an insulating layer, thereby obtaining a high-barrier, corrosion-resistant overhead cable.

[0024] Example 3 This embodiment provides a high-barrier, corrosion-resistant overhead cable, which comprises, from the inside out, a copper conductor, a shielding layer, and an insulation layer. The insulation layer comprises the following raw materials in parts by weight: 75 parts high-density polyethylene, 32 parts polymethyl methacrylate, 12 parts modified porous kaolin, 22 parts ethylene-vinyl acetate copolymer, 6 parts maleic anhydride-grafted polyethylene, 1.5 parts a mixture of antioxidants 1010 and 168 (mass ratio 1:2), 25 parts a mixture of decabromodiphenyl ethane and antimony trioxide (mass ratio 3:1), and 1.2 parts polyethylene wax. In this embodiment, the preparation steps of the modified porous kaolin are as follows: (1) Disperse 100g of kaolin in 1000g of 10% hydrochloric acid aqueous solution, stir at 80℃ for 4h, filter, wash and dry to obtain acid-etched kaolin; (2) Disperse 80g of acid-etched kaolin in 500mL of anhydrous ethanol, add 4.0g of silane coupling agent KH550 (mass ratio of acid-etched kaolin to 5:100), reflux at 80℃ for 6h, filter, wash and dry to obtain aminosilanized porous kaolin; (3) Disperse 50g of aminosilanized porous kaolin in 300mL of toluene, add 16.7g of maleic anhydride-grafted polymethyl methacrylate (mass ratio of maleic anhydride to silanized porous kaolin is 1:3), react at 100℃ for 8h, filter, wash and dry to obtain modified porous kaolin.

[0025] In this embodiment, the preparation steps of the high-barrier corrosion-resistant overhead cable include: S1. Cover the outside of the copper conductor with a semi-conductive shielding material to obtain a semi-finished product; S2. Weigh the raw materials of each component of the insulation layer according to the weight, mix them evenly, and then melt-blend and granulate them at 180°C using a twin-screw extruder to obtain the insulation material; S3. The insulating material is extruded onto the outside of the semi-finished product through an extruder to form an insulating layer, thereby obtaining a high-barrier, corrosion-resistant overhead cable.

[0026] Comparative Example 1 Based on Example 1, adjustments were made, but unlike Example 1, unmodified natural kaolin was used to replace the modified porous kaolin.

[0027] Comparative Example 2 Based on Example 1, adjustments were made. Unlike Example 1, kaolin modified only by KH550 (the preparation method is the same as steps (1) and (2) in Example 1, but without the secondary modification in step (3)) was used to replace the modified porous kaolin.

[0028] Comparative Example 3 Based on Example 1, adjustments were made. Unlike Example 1, kaolin that was only modified by KH550 and modified twice (the preparation method is: omitting step (1) acid etching to create pores, and directly modifying the original kaolin in steps (2) and (3) in sequence) was used to replace the modified porous kaolin.

[0029] Comparative Example 4 The method is based on Example 1, but with adjustments. Unlike Example 1, no modified porous kaolin is added, and the reduced amount is made up by high-density polyethylene.

[0030] Comparative Example 5 The method was adjusted based on Example 1, except that the silane coupling agent used was KH560.

[0031] Comparative Example 6 The method is based on Example 1, but with the difference that the silane coupling agent is KH570.

[0032] Comparative Example 7 The method is based on Example 1, but with adjustments. Unlike Example 1, maleic anhydride-grafted polyethylene compatibilizer is not added, and the reduced amount is made up by high-density polyethylene.

[0033] Test Example 1: The high-barrier, corrosion-resistant overhead cables prepared in the aforementioned examples and comparative examples were subjected to the following tests: Tensile strength and elongation at break: Refer to GB / T 1040.3-2018, test speed 50 mm / min; Volume resistivity: Refer to GB / T 1410-2006, test voltage 1000V; Acid resistance test: The sample is immersed in a 10% sulfuric acid aqueous solution for 30 days, the tensile strength is tested, and the retention rate is calculated; Alkali resistance test: The sample is immersed in a 10% NaOH aqueous solution for 30 days, the tensile strength is tested, and the retention rate is calculated; Salt spray resistance test: Refer to GB / T 2423.17-2013, perform a neutral salt spray test for 480 hours, and observe the surface corrosion. Flame retardant performance: The limiting oxygen index (LOI) was tested in accordance with GB / T 2406.2-2009. The test results are shown in Table 1 below: Table 1

[0034] Based on the aforementioned data, Examples 1-3 all exhibit excellent overall performance; their tensile strength ranges from 24.8 to 26.8 MPa, and their elongation at break ranges from 575% to 612%, both significantly higher than the comparative examples. Example 3, due to its highest amount of modified kaolin and higher grafting ratio, demonstrates the best mechanical properties. The volume resistivity of all examples is above 5.9 × 10⁻⁶. 15 The tensile strength is above Ω·cm, indicating that the insulation layer has excellent electrical insulation properties. After immersion in acid and alkali solutions for 30 days, the tensile strength retention rate is over 90%, and there is no surface corrosion after 480 hours of salt spray, proving that the insulation layer has excellent chemical corrosion resistance. The limiting oxygen index (LOI) is between 31.8% and 34%, all meeting the standard for flame-retardant materials (LOI>27%), with Example 3 having the highest flame retardant content and an LOI of 34%.

[0035] In Comparative Example 1, the natural kaolin, without acid etching for pore formation and surface modification, exhibited poor dispersibility and weak interfacial bonding in the polymer matrix, existing only as an inert filler. This resulted in a significant overall decline in mechanical properties, electrical insulation properties, and corrosion resistance, with obvious corrosion observed after salt spray testing. This demonstrates that the modified porous structure is crucial for improving the overall performance of the insulation layer.

[0036] In Comparative Example 2, only KH550 silane coupling agent modification was performed. Although this improved the compatibility between kaolin and the matrix to some extent, the lack of an acid etching pore-forming step resulted in a small specific surface area and few active sites for the kaolin. Furthermore, without secondary modification by grafting maleic anhydride with polymethyl methacrylate, effective interfacial chemical bonding could not be formed. The performance was improved compared to Comparative Example 1, but was still significantly inferior to Example 1. Moderate corrosion was observed in the salt spray test, indicating that simple silanization modification is insufficient to impart excellent corrosion resistance to the material.

[0037] Comparative Example 3 retained the KH550 modification and maleic anhydride-grafted polymethyl methacrylate secondary modification steps, but omitted the acid etching pore-forming process. Although interfacial compatibility and chemical bonding were somewhat guaranteed, the specific surface area and loading capacity of kaolin were limited due to the lack of a porous structure formed by acid etching, failing to fully effectively block the penetration of corrosive media. Its performance was better than Comparative Examples 1 and 2, but still inferior to Example 1. Slight corrosion was observed in the salt spray test, proving that acid etching pore-forming is a key step in obtaining excellent corrosion resistance.

[0038] Comparative Example 4 contained no modified porous kaolin; the insulation layer consisted only of a polymer matrix and flame retardants. All performance indicators were the worst: mechanical properties decreased significantly, electrical insulation properties were significantly reduced, acid, alkali, and salt spray corrosion resistance were severely deteriorated, and flame retardancy also declined. Particularly in terms of mechanical properties, due to the complete removal of the PMMA-grafted modified porous kaolin, the system lost its most important compatibilizing node and interfacial bridge. This led to severe macroscopic phase separation between the high-density polyethylene (HDPE) and polymethyl methacrylate (PMMA), resulting in extremely amplified internal stress defects. Consequently, not only was the mechanical strength reduced to its lowest level, but the elongation at break also plummeted. This demonstrates that modified porous kaolin plays multiple crucial roles in this insulation layer system: enhancing mechanical properties (acting as a compatibility and stress transfer agent), improving electrical insulation, constructing a physical barrier against corrosive media, and synergistically enhancing flame retardancy; it is an indispensable core functional component.

[0039] In Comparative Example 5, KH560 is an epoxy-based silane coupling agent. The reactivity of its epoxy groups with the hydroxyl groups on the kaolin surface is lower than that of the amino groups in KH550. Furthermore, the chemical compatibility between the epoxy groups and the subsequently grafted maleic anhydride-grafted polymethyl methacrylate is poor, making it difficult to form stable chemical bonds. This leads to a decrease in interfacial bonding strength, and all properties are lower than in Example 1, but still better than the unmodified Comparative Examples 1-2. This indicates that while KH560 can play a certain modifying role, its effect is not as good as that of KH550.

[0040] In Comparative Example 6, KH570 is a methacryloyloxysilane coupling agent. Its double bond structure exhibits certain reactivity, and its compatibility with maleic anhydride-grafted polymethyl methacrylate is better than that of KH560, but still not as efficient as the amidation reaction between the amino and anhydride groups of KH550. Its performance is better than Comparative Example 5 (KH560), and close to but slightly lower than that of Example 1 (KH550), indicating that KH550 is the optimal silane coupling agent choice in this system, as its amino functional groups can form stronger and more stable chemical bonds with the maleic anhydride-grafted polymer.

[0041] The performance of Comparative Example 7 without compatibilizer was significantly worse than that of Example 1, demonstrating that maleic anhydride-grafted polyethylene as a compatibilizer is crucial for improving the HDPE / PMMA two-phase interface and enhancing overall performance.

[0042] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-barrier, corrosion-resistant overhead cable, characterized in that, From the inside out, it comprises a conductor, a shielding layer, and an insulating layer. The insulating layer comprises the following raw materials in parts by weight: 60-80 parts of high-density polyethylene, 25-35 parts of polymethyl methacrylate, 8-12 parts of modified porous kaolin, 15-25 parts of ethylene-vinyl acetate copolymer, 3-6 parts of compatibilizer, 0.5-2 parts of antioxidant, 15-25 parts of flame retardant, and 0.5-1.5 parts of lubricant. The modified porous kaolin is obtained by acid etching to create pores and then by sequentially modifying it with a silane coupling agent and maleic anhydride grafted with polymethyl methacrylate.

2. The high-barrier, corrosion-resistant overhead cable according to claim 1, characterized in that, The method for preparing the modified porous kaolin includes: (1) Acid etching to create pores: Kaolin is dispersed in hydrochloric acid aqueous solution and stirred at 60~80℃ for 4~8h. After filtration, washing and drying, acid-etched kaolin is obtained. (2) First modification: Disperse acid-etched kaolin in anhydrous ethanol, add silane coupling agent, reflux reaction at 60~80℃ for 6~10h, filter, wash and dry to obtain aminosilanized porous kaolin; (3) Second modification: Aminosilanized porous kaolin is dispersed in toluene, maleic anhydride-grafted polymethyl methacrylate is added, and the mixture is reacted at 80~100℃ for 8~12h. After filtration, washing and drying, modified porous kaolin is obtained.

3. The high-barrier, corrosion-resistant overhead cable according to claim 2, characterized in that, The hydrochloric acid aqueous solution has a mass fraction of 10-20%, and the mass ratio of kaolin to hydrochloric acid aqueous solution is 1:5-1:

10.

4. The high-barrier, corrosion-resistant overhead cable according to claim 2, characterized in that, The silane coupling agent is KH550; and the mass ratio of the silane coupling agent to the acid-etched kaolin is 1:100 to 5:

100.

5. A high-barrier, corrosion-resistant overhead cable according to claim 2, characterized in that, The mass ratio of maleic anhydride-grafted polymethyl methacrylate to silanized porous kaolin is 1:3 to 1:

6.

6. The high-barrier, corrosion-resistant overhead cable according to claim 1, characterized in that, The compatibilizer is maleic anhydride-grafted polyethylene.

7. A high-barrier, corrosion-resistant overhead cable according to claim 1, characterized in that, The antioxidant is a mixture of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1 to 1:

2.

8. A high-barrier, corrosion-resistant overhead cable according to claim 1, characterized in that, The flame retardant is a mixture of decabromodiphenyl ethane and antimony trioxide in a mass ratio of 2:1 to 3:

1.

9. A high-barrier, corrosion-resistant overhead cable according to claim 1, characterized in that, The lubricant is zinc stearate or polyethylene wax.

10. The high-barrier, corrosion-resistant overhead cable according to any one of claims 1-9, characterized in that, The preparation steps of the high-barrier corrosion-resistant overhead cable include: S1, covering the outer side of the conductor with shielding material to obtain a semi-finished product; S2, weighing the raw materials of each component of the insulation layer according to the weight, mixing them evenly, and then melting and granulating them through a twin-screw extruder to obtain an insulating material; S3, extruding the insulating material through an extruder to cover the outer side of the semi-finished product to form an insulation layer, thereby obtaining a high-barrier corrosion-resistant overhead cable.

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