Stretch-resistant environment-friendly energy-saving cable and preparation method thereof

Abstract

The invention discloses a stretch-resistant environment-friendly energy-saving cable and a preparation method, the stretch-resistant environment-friendly energy-saving cable comprises a cable core, a winding shielding layer, an insulating layer and a sheath in sequence from inside to outside, the cable core is formed by twisting a plurality of strands of independent wire cores, and the wire core comprises an aluminum core, a copper sheath, a modified BN lubricating layer and an insulating sheath in sequence from inside to outside. Paraffin-based filler is filled between the adjacent wire cores. According to the invention, the copper-clad aluminum structure replaces the existing pure copper or pure aluminum conductor, so that the balance between high conductivity and light weight is realized; vinyl modified BN is subjected to hydrosilylation with hydrogen-containing silicone oil and silica gel of an insulating skin to form a chemically anchored interface enhanced BN lubricating structure with enhanced and heat-conducting double functions, so that powder is prevented from falling off during dragging, and a BN layer slides to compensate for the deformation difference of metal / silica gel; expanded graphite is introduced to adsorb paraffin, so that deformation heat energy can be absorbed, and plastic deformation is reduced; and through annular pre-embedding of the aramid ropes and vulcanization reinforcement of the XLPE sheath, the tensile strength and the aging resistance are greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of energy-saving cables suitable for high-frequency power transmission conditions, and in particular to a tensile-resistant, environmentally friendly, energy-saving cable and a preparation method thereof. Background Art

[0002] Energy-saving cables refer to special cables that use low-resistivity conductor cores and are suitable for high-load, long-distance, and long-term operation scenarios. Their conductors are mostly made of high-purity oxygen-free copper (copper content ≥99.99%) or rare earth high-iron aluminum alloy (rare earth elements are added to optimize conductivity), but can cope with the loss of high-frequency alternating current. The general line loss rate is less than 3%, especially in scenarios such as industrial high currents and power grid trunk lines, and the annual electricity saving effect is significant.

[0003] However, existing energy-saving cables still have the following shortcomings: 1) Pure copper conductors are expensive and dense (8.96 g / cm³). While pure aluminum conductors are lightweight (density 2.7 g / cm³), replacing them with pure aluminum results in high-frequency (≥30Hz) resistivity (measured at 165% of pure copper cable) and insufficient mechanical strength (aluminum has a tensile strength of only 80 MPa and is prone to deformation and fracture during drag laying). 2) The thermal expansion coefficient of the metal conductor and the insulation layer is very different (aluminum: 23×10 -6 / ℃;Silica gel:250×10 -6 / ℃), the interface shear stress during bending or stretching induces delamination, leading to partial discharge (breakdown), lubricant shedding (increasing friction loss), and thermal-mechanical coupling failure (inducing plastic deformation of the insulation layer and filler migration and bulging). Summary of the Invention

[0004] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a tensile-resistant, environmentally friendly and energy-saving cable and a preparation method thereof.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: In a first aspect, the present application provides a stretch-resistant, environmentally friendly, and energy-saving cable, which comprises, from the inside out, a cable core, a winding shielding layer, an insulation layer, and a sheath. The cable core is formed by twisting multiple independent wire cores. The wire core comprises, from the inside out, an aluminum core, a copper sheath, a modified BN lubricating layer, and an insulation sheath. Paraffin-based fillers are filled between adjacent wire cores. The aluminum core is a lightweight conductor, reducing costs and energy consumption.

[0006] The outer layer of the copper sheath is nickel-plated to avoid high-temperature oxidation or other negative reactions that corrode copper during the extrusion process. The thickness of the copper sheath is 15-25% of the radius of the aluminum core, which is used to form a pure copper layer with high conductivity. Under the alternating current of power frequency (50Hz / 60Hz) or higher frequency, the skin effect causes the current to flow mainly in the outer copper layer. As long as the thickness of the copper layer is greater than or equal to the penetration depth δ at this frequency, most of the current will be confined to the copper layer; for example, when the power frequency is 50Hz, the penetration depth of pure copper δ≈9.3mm, which is not too large for cables with a diameter of less than 35mm. 2 ), a reasonably designed copper layer thickness (such as 0.2mm-0.5mm) is sufficient to carry most industrial frequency AC currents, and the copper-clad aluminum core can improve conductivity and oxidation resistance; The low-density, low-cost aluminum core of the inner core mainly plays the role of mechanical support and conduction of DC or extremely low-frequency current. In DC working conditions (such as photovoltaic or wind power), it has the function of sharing the conductivity of copper. Under AC working conditions, due to the skin effect, the proportion of current contributed by the aluminum core is very small.

[0007] Under AC conditions, the effective conductive area of ​​a copper-clad aluminum conductor is approximately the cross-sectional area of ​​the copper layer. The aluminum core coating improves conductivity and oxidation resistance. Although aluminum's electrical conductivity is only about 61% of copper's, since current rarely penetrates the aluminum core, the overall AC resistance depends primarily on the thickness and conductivity of the copper layer, rather than the average conductivity of the entire cross-section. Compared to solid aluminum conductors, the copper layer provides a highly conductive surface path, significantly reducing the additional resistance increment caused by the skin effect (the part where AC resistance exceeds DC resistance), thereby reducing skin effect losses. Furthermore, copper has a higher tensile strength than aluminum, which can significantly improve the tensile properties of the aluminum cable core without significantly reducing conductivity, while reducing costs. The modified BN lubricating layer is formed by mixing vinyl-modified BN and vinyl polydimethylsiloxane (Vi-PDMS, a viscous liquid with a molecular weight of 20,000-25,000, a vinyl content of 2.5-3.0 mol%, and a viscosity of 8,000-1,000 mPa·s) in a weight ratio of 1.8-2.3:1. The modified BN lubricating layer is then subjected to a vulcanization reaction with silica gel to form a fixed thin lubricating structure with the insulating layer. The synthesis steps of the vinyl-modified BN are as follows: S01, h-BN is dispersed in concentrated nitric acid aqueous solution and subjected to BN hydroxylation pretreatment to obtain hydroxylated BN with a hydroxyl density of 12-15 / nm 2 ; S02, using anhydrous toluene, deionized water, and triethylamine to perform silane hydrolysis activation on KH-570 to obtain a hydrolyzed silane solution; S03, performing a silane grafting reaction using hydroxylated BN and a hydrolyzed silane solution to obtain a reaction solution; S04. Post-treating and purifying the reaction solution to obtain vinyl-modified BN.

[0008] Preferably, step S01 (BN hydroxylation pretreatment) specifically includes: 20 g of h-BN (sheet diameter 1-5 μm, thickness ≤ 100 nm) was dispersed in 200 ml of a 65% by weight concentrated nitric acid aqueous solution, refluxed at 80 ° C for 6 hours, centrifuged, washed with deionized water until neutral (pH = 7), and vacuum dried (120 ° C, 4 h) to obtain hydroxylated BN (i.e., HO-BN) with a hydroxyl density of 12-15 / nm 2 ; Step S02 (silane hydrolysis activation) specifically includes: Under dry nitrogen protection, dissolve 5g of KH-570 (γ-methacryloxypropyltrimethoxysilane) in 100ml of anhydrous toluene; add 0.5ml of deionized water (molar ratio of KH-570:H2O = 1:1.2) dropwise, stir for 30min; add 0.1g of triethylamine (TEA), and react at 40℃ for 2h to obtain a hydrolyzed silane solution: The hydrolysis reaction formula is as follows:

[0009] Step S03 (silane grafting reaction) specifically includes: Under nitrogen protection, 10 g of hydroxylated BN was added to the hydrolyzed silane solution and ultrasonically dispersed for 30 min (power 300 W). The temperature was raised to 110°C and refluxed for 8 h to obtain a reaction solution. The methanol content in toluene was measured by GC every 2 h. The reaction endpoint was when the methanol release was greater than 95% of the theoretical value. Step S03 (post-processing and purification) specifically includes: The reaction solution was cooled to room temperature and centrifuged (8000 rpm, 10 min) to collect the solid. The solid was ultrasonically washed three times with toluene and ethanol to remove physically adsorbed silane. The solid was then dried under vacuum at 60°C for 12 h to obtain vinyl-modified BN (Vi-BN).

[0010] Preferably, the insulating skin is made of silicone material, and the insulating skin is made of the following raw materials: 10Kg vinyl silicone rubber, 0.4-0.5Kg polyvinyl silicone rubber, 1.2-1.5kg hydrogenated silicone oil, 0.1-0.15kg platinum (0)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane (Karstedt catalysis, promoting the cross-linking reaction between the active hydrogen of hydrogenated silicone oil and vinyl) and 1-5g 1-ethynylcyclohexanol (inhibitor, avoiding local premature cross-linking into gel).

[0011] Preferably, the winding shielding layer is spirally wrapped with conductive PI tape, taking into account electromagnetic shielding, high temperature resistance and flexibility.

[0012] Preferably, the insulating layer is made of PVC rubber, which has a low cost. Aramid ropes are distributed in an annular pattern inside the insulating layer to further improve the tensile strength and the ability to resist large deformation of the cable core.

[0013] Preferably, the sheath is made of cross-linked polyethylene (XLPE), an environmentally friendly material with high weather resistance, aging resistance and mechanical strength.

[0014] Preferably, the paraffin-based filler is a mixture of paraffin (melting at 55-65°C and absorbing heat), expanded graphite (pore size 100-300 μm) and nano-alumina (particle size 15-60 nm) in a weight ratio of 10:1-2:1-2; Preferably, the insulating sheath is made of: Vinyl silicone rubber is a long-chain polysiloxane with vinyl short-links at both ends of the macromolecular chain. It is in the form of solid rubber with a molecular weight of 300,000-400,000 and a vinyl content of 0.02-0.03mmol vinyl / g vinyl silicone rubber. Polyvinyl silicone rubber is a long-chain polysiloxane with vinyl groups at both ends or in the side chains of the macromolecular chain. It is in the form of solid rubber with a molecular weight of 300,000-400,000 and a vinyl content of 2-3 mmol vinyl / g polyvinyl silicone rubber.

[0015] Hydrogenated silicone oil is polydimethylsilicone oil with Si-H bonds and a hydrogen content of 4-6 mmol / g.

[0016] Modified BN lubricating layer: located between the copper sheath and the insulating sheath, and is obtained by reacting hydroxylated BN with vinyl-containing silane.

[0017] Insulation: Made of silicone rubber, vulcanized at 200°C to crosslink polysiloxane, hydrogenated silicone oil and modified BN to form a reinforced interface.

[0018] In a second aspect, the present invention further provides a method for preparing the aforementioned stretch-resistant, environmentally friendly and energy-saving cable, comprising the following steps: S1. Prepare a single-strand wire core, specifically including: S101, aluminum core processing The electrical grade aluminum rod is drawn to the designed diameter (e.g. 2.5-6mm), cut into fixed length aluminum wires, and the surface is polished to remove the oxide layer to obtain the aluminum core; S102, copper cladding and nickel plating A continuous extrusion cladding process is used to form a copper sheath on the aluminum core. The thickness of the copper layer is controlled to be 15-25% of the radius of the aluminum core (e.g. 0.2-0.5mm). A nickel layer (thickness ≥ 1μm) is electroplated on the outer surface of the copper sheath to prevent high-temperature oxidation. S103, coating modified BN lubricating layer Vinyl-modified BN and vinyl polydimethylsiloxane are mixed in a weight ratio of 1.8-2.3:1, stirred into a uniform slurry, and applied to the surface of the copper sheath by dip coating or spraying to form a thin layer (thickness 5-10 μm), and pre-cured at 80°C for 5 minutes to obtain a modified BN lubricating layer; S104, extrusion and vulcanization The insulation sheath raw materials are mixed at 40-50°C to form an extrusion material, which is then extruded onto the modified BN lubricating layer. The material is then pre-vulcanized at 120-130°C for 10 minutes to allow the hydrogenated silicone oil to penetrate into the BN layer and cross-link. The material is then infrared-vulcanized at 200±5°C for 20 minutes to form a silicone / BN reinforced structure, thereby obtaining a single-strand wire core. The extrusion material is mixed at 40-50°C, then extruded onto the modified BN lubricating layer at 30-40°C, and then pre-cured at 120-130°C to allow the hydrogenated silicone oil to penetrate into the modified BN lubricating layer and react with the vinyl modified BN and vinyl polydimethylsiloxane to cross-link. The insulating layer is then formed by infrared vulcanization at 200±5°C, where the vinyl modified BN is connected to the silicone network to form a silicone / BN reinforced thin layer structure. This prevents powder from falling off during the lubrication process, which would otherwise cause an uneven lubricating layer. The stability of the lubricating layer is particularly important due to the difference in deformation between the silicone and the metal core during dragging, stretching, or bending. S2, cable core twisting The raw materials of paraffin-based filler are heated at 60℃ to form a paste, which is then coated on the outside of the cable core (with a thickness of 3-5μm). Multiple single-strand cores are then bundled in a concentric twisted manner with a twisting pitch ≤ 15 times the outer diameter of the cable core. The twisted cable core bundle is passed through a cylindrical through hole to form a round shape, and then cooled to obtain a paraffin-coated cable core. S3, shielding layer wrapping treatment On the paraffin-coated cable core, spirally wrap the conductive polyimide tape (50cm in width, with a wrapping overlap ratio of 40-60%) to form a tape shielding layer; S4, extruded insulation layer PVC rubber is extruded outside the shielding layer to form an insulating layer. Aramid rope is pre-placed in the die of the extruder and evenly distributed in a ring shape inside the insulating layer (with a spacing of 2-3mm). The extrusion temperature is 160-180℃ and the shape is set after cooling. S5, sheath molding Cross-linked polyethylene (XLPE) is extruded outside the insulation layer at an extrusion temperature of 120-140°C (to avoid high temperature damage to the aramid rope), and then infrared vulcanization is used at 180°C for 30 minutes to obtain a sheath; S6. Post-processing The sheath obtained by S5 is cooled to room temperature in a water cooling tank, reeled by tension control (to prevent deformation), and the irregular end section is cut off to obtain an energy-saving cable product.

[0019] Performance Testing Tensile strength test (≥150% design load).

[0020] Conductivity test (50Hz AC resistance ≤ 110% of pure copper cable of the same specification).

[0021] High voltage insulation test (power frequency 3.5kV / 5min without breakdown).

[0022] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention replaces existing pure copper or pure aluminum conductors with a copper-clad aluminum structure, achieving a balance between high conductivity and lightweight. Copper usage is reduced by at least 70%, reducing costs by at least 30%, while the high-frequency resistivity is only about 8% higher than that of pure copper conductors. Precise control of the copper layer thickness (15-25% of the aluminum core radius) ensures that 98% of the current within the skin depth is conducted by the copper layer. A copper layer strength of ≥200 MPa compensates for the weaknesses of the aluminum core, resulting in a 120% increase in tensile strength compared to pure aluminum cables. The aluminum core is also 30% lighter, reducing energy consumption during transportation and installation.

[0023] 2. The present invention pre-crosslinks vinyl-modified BN with vinyl polydimethylsiloxane (Vi-PDMS), and then allows hydrogenated silicone oil to react with the insulating silicone layer to form a BN-silicone interpenetrating network, forming a chemically anchored interface-enhanced BN lubrication structure with dual functions of reinforcement and thermal conductivity. This prevents powder shedding during dragging, and the BN layer slips to compensate for the metal / silicone deformation, with a breakdown voltage of >5.0 kV.

[0024] 3. The present invention introduces expanded graphite to absorb paraffin and provides a highly thermally conductive alumina reinforcement. The resulting paraffin-based filler utilizes the melting of paraffin at 55-65°C to absorb deformation heat energy, reducing plastic deformation. Nano-Al2O3 is used to fill gaps, accelerating heat diffusion and suppressing conductor temperature rise.

[0025] 4. The present invention also greatly improves the tensile strength and aging resistance by pre-embedding the aramid rope in an annular manner and strengthening the XLPE sheath by vulcanization. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a structural schematic diagram of a tensile-resistant, environmentally friendly and energy-saving cable proposed by the present invention.

[0027] In the figure: cable core 1, wire core 101, aluminum core 101A, copper sheath 101B, modified BN lubricating layer 101C, insulating sheath 101D, winding shielding layer 2, insulating layer 3, aramid rope 301, sheath 4, paraffin-based filler 5. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the existing known technologies. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0029] This embodiment provides a method for preparing a stretch-resistant, environmentally friendly, and energy-saving cable, comprising the following steps: S1. Prepare a single-strand wire core. This step specifically includes: S101, aluminum core processing The electrical grade aluminum rod is drawn to the designed diameter (taking 2.5mm as an example), cut into fixed length aluminum wires, polished on the surface, and the oxide layer is removed to obtain the aluminum core 101A; S102, copper cladding and nickel plating A continuous extrusion coating process is used to form a copper sheath 101B on the outside of the aluminum core 101A. The thickness of the copper layer is controlled to be 15-25% of the radius of the aluminum core (e.g., 0.19-0.31 mm). Electroplating nickel layer (thickness ≥ 1μm) on the outer surface of copper cladding 101B to prevent high temperature oxidation; S103, coating modified BN lubricating layer Vinyl-modified BN and vinyl polydimethylsiloxane are mixed in a weight ratio of 1.8-2.3:1, stirred into a uniform slurry, and applied to the surface of the copper sheath by dip coating or spraying to form a thin layer (thickness 5-10 μm), and pre-cured at 80°C for 5 minutes to obtain a modified BN lubricating layer; S104, extrusion and vulcanization The raw materials of the insulation sheath 101D are mixed and kneaded at 40-50°C to form an extrusion material, which is then extruded onto the modified BN lubricating layer 101C. The material is then pre-vulcanized at 120-130°C for 10 minutes to allow the hydrogenated silicone oil to penetrate into the BN layer and cross-link. The material is then infrared-vulcanized at 200±5°C for 20 minutes to form a silicone / BN reinforcement structure, thereby obtaining the single-strand wire core 101. The extrusion material is mixed at 40-50°C, then extruded onto the modified BN lubricating layer 101C at 30-40°C, and then pre-cured at 120-130°C to allow the hydrogenated silicone oil to penetrate into the modified BN lubricating layer 101C and react with the vinyl-modified BN and vinyl polydimethylsiloxane to form a cross-linking reaction. The insulating layer 101D is then formed by infrared vulcanization at 200±5°C, where the vinyl-modified BN is connected to the silicone network to form a silicone / BN reinforced thin layer structure. This prevents powder from falling off during the lubrication process, which would otherwise result in an uneven lubricating layer. The stability of the lubricating layer is particularly important due to the difference in deformation between the silicone and the metal core during dragging, stretching, or bending. S2, cable core twisting The raw material of the paraffin-based filler 5 is heated at 60°C to form a paste, which is then coated on the outside of the cable core 101 (with a thickness of 3-5 μm). Multiple single-strand cable cores 101 are then bundled in a concentric twisted manner with a twisting pitch ≤ 15 times the outer diameter of the cable core. The twisted cable core bundle is passed through a cylindrical through hole to form a round shape, and then cooled to obtain a paraffin-coated cable core. S3, shielding layer wrapping treatment Helically wrap a conductive polyimide tape (50 cm wide, with a wrapping overlap ratio of 40-60%) around the paraffin-coated cable core to form a tape shielding layer 2; S4, extruded insulation layer An insulating layer is formed by extruding PVC rubber outside the shielding layer. Aramid rope 301 is pre-placed in the die of the extruder and evenly distributed in an annular shape inside the insulating layer 3 (with a spacing of 2-3 mm). The extrusion temperature is 160-180°C and the layer is cooled to set. S5, sheath molding Cross-linked polyethylene (XLPE) is extruded outside the insulation layer at an extrusion temperature of 120-140°C (to avoid high temperature damage to the aramid rope), and then infrared vulcanization is performed at 180°C for 30 minutes to obtain a sheath 4; S6. Post-processing The sheath 4 obtained in S5 is cooled to room temperature in a water cooling tank, reeled by tension control (to prevent deformation), and the irregular end section is cut off to obtain an energy-saving cable product.

[0030] This embodiment also provides a product obtained by the above-mentioned preparation process: a tensile-resistant, environmentally friendly, and energy-saving cable, comprising, from the inside out, a cable core 1, a winding shielding layer 2, an insulating layer 3, and a sheath 4. The cable core 1 is formed by twisting multiple independent wire cores 101. The wire core 101 comprises, from the inside out, an aluminum core 101A, a copper sheath 101B, a modified BN lubricating layer 101C, and an insulating sheath 101D. Paraffin-based fillers 5 are filled between adjacent wire cores 101. Aluminum core 101A is a lightweight conductor that reduces costs and energy consumption.

[0031] The outer layer of the copper cladding 101B is nickel-plated to prevent high-temperature oxidation or other negative reactions that corrode the copper during the extrusion process. The thickness of the copper cladding 101B is 15-25% of the radius of the aluminum core 101A. The modified BN lubricating layer 101C is formed by mixing vinyl-modified BN and vinyl polydimethylsiloxane in a weight ratio of 1.8-2.3:1. The modified BN lubricating layer 101C is subsequently vulcanized with silicone to form a fixed thin lubricating structure with the insulating layer 101D. The synthesis steps of vinyl-modified BN are as follows: S01, BN hydroxylation pretreatment 20 g h-BN was dispersed in 200 ml of 65% by weight concentrated nitric acid aqueous solution, refluxed at 80 ° C for 6 hours, centrifuged, washed with deionized water until neutral, and vacuum dried to obtain hydroxylated BN with a hydroxyl density of 12-15 / nm 2 ; S02, silane hydrolysis activation Under dry nitrogen protection, dissolve 5g KH-570 in 100ml anhydrous toluene; add 0.5ml deionized water dropwise and stir for 30min; add 0.1g triethylamine and react at 40℃ for 2h to obtain hydrolyzed silane solution: The hydrolysis reaction formula is as follows:

[0032] S03, silane grafting reaction Under nitrogen protection, 10 g of hydroxylated BN was added to the hydrolyzed silane solution and ultrasonically dispersed for 30 min. The temperature was raised to 110°C and refluxed for 8 h to obtain a reaction solution. The methanol content in toluene was measured every 2 h. The reaction endpoint was when the methanol release amount was greater than 95% of the theoretical value. S04, post-processing and purification The reaction solution was cooled to room temperature and the solid was collected by centrifugation. The solid was ultrasonically washed with toluene and ethanol three times to remove physically adsorbed silane. The solid was vacuum dried at 60° C. for 12 h to obtain vinyl-modified BN.

[0033] The insulation cover 101D is made of silicone and is made from the following materials: 10kg vinyl silicone rubber, 0.4-0.5kg polyvinyl silicone rubber, 1.2-1.5kg hydrogenated silicone oil, 0.1-0.15kg platinum (0-1,3-divinyl-1,1,3,3-tetramethyldisiloxane) as a catalyzer to promote crosslinking between the active hydrogen of the hydrogenated silicone oil and the vinyl groups, and 1-5g 1-ethynylcyclohexanol as an inhibitor to prevent premature local crosslinking into gel.

[0034] The winding shielding layer 2 is spirally wrapped with conductive PI tape, taking into account electromagnetic shielding, high temperature resistance and flexibility.

[0035] The insulating layer 3 is made of PVC rubber, which is relatively low in cost. Aramid ropes 301 are distributed in an annular shape inside the insulating layer 3 to further improve the tensile strength and the ability to resist large deformation of the cable core.

[0036] The sheath 4 is made of cross-linked polyethylene (XLPE), an environmentally friendly material with high weather resistance, aging resistance and mechanical strength.

[0037] The paraffin-based filler 5 is made of paraffin (melting at 55-65°C and absorbing heat), expanded graphite (pore size 100-300 μm) and nano-alumina (particle size 15-60 nm) mixed in a weight ratio of 10:1-2:1-2; Among them, the raw materials of insulation 101D are: Vinyl silicone rubber is a long-chain polysiloxane with vinyl short-links at both ends of the macromolecular chain. It is in the form of solid rubber with a molecular weight of 300,000-400,000 and a vinyl content of 0.02-0.03mmol vinyl / g vinyl silicone rubber. Polyvinyl silicone rubber is a long-chain polysiloxane with vinyl groups at both ends or in the side chains of the macromolecular chain. It is in the form of solid rubber with a molecular weight of 300,000-400,000 and a vinyl content of 2-3 mmol vinyl / g polyvinyl silicone rubber.

[0038] Hydrogenated silicone oil is polydimethylsilicone oil with Si-H bonds and a hydrogen content of 4-6 mmol / g.

[0039] Next, for a method for preparing a tensile-resistant, environmentally friendly and energy-saving cable, the following Examples 1-3 are provided, as shown in Table 1 below: Table 1. High-performance cable formulations

[0040] The following comparative examples 1-7 were designed based on Example 1, as shown in Table 2 below: Table 2. High-performance cable formulations with single factor changes

[0041] It should be noted that, in Comparative Example 4, vinyl-free polymethylsiloxane rubber with a molecular weight of 1,000,000 is used to replace the vinyl silicone rubber and polyvinyl silicone rubber in Example 1.

[0042] Performance Testing 1. Tensile strength test (≥150% design load) Referencing IEC 60228 and GB / T 5023.5-2008 conductor tensile tests, with a design load of 67% of the cable's nominal breaking strength (with a safety factor of 1.5), this test verifies the cable's ability to resist deformation under extreme mechanical stresses (such as drag laying and wind loads) to ensure structural integrity.

[0043] Test Method 1.1. Sample preparation: Cut a 1m long cable sample and crimp copper terminals on both ends (to prevent the clamp from slipping); Preload 50% of the design load (eliminate initial gap).

[0044] 1.2 Loading process: Load at a rate of 10 mm / min to 150% of the design load (e.g. if the design load is 10 kN, load to 15 kN); Maintain the load for 10 minutes and record the real-time deformation (accuracy of laser displacement sensor ±0.01mm).

[0045] 1.3、Qualification criteria: Permanent deformation rate ≤ 3% (length change after unloading / original length); No sheath cracks, shield exposure, or conductor breakage.

[0046] 2. Conductivity test (50Hz AC resistance ≤ 110% of pure copper cable of the same specification) Refer to the IEC 60287 AC resistance measurement method to test the actual conductivity efficiency of copper-clad aluminum conductors under the quantitative skin effect and verify their energy-saving characteristics.

[0047] Comparison benchmark: Pure copper cable with the same cross-sectional area (e.g., 35 mm²) (resistivity 0.01724 Ω·mm² / m).

[0048] Test Method 2.1, Environmental control: Maintain a constant temperature of 20±1°C to eliminate the influence of temperature coefficient (copper: 0.00393 / °C).

[0049] 2.2, Four-terminal measurement: Use a precision LCR meter (Agilent 4294A) at 50Hz frequency and 1A current (to avoid self-heating effects) to measure the AC resistance R of a 1km cable. ac :

[0050] 3. High voltage insulation test (power frequency 3.5kV / 5min without breakdown) Evaluate the dielectric strength of a multi-layer insulation system (modified BN layer + silicone + XLPE sheath) under overvoltage according to the IEC 60502-2 power frequency withstand voltage test.

[0051] Test Method 3.1. Sample processing: The samples were immersed in 25°C salt water (conductivity 20 mS / m) for 24 h to simulate a humid environment.

[0052] 3.2, Boosting procedure: Boost the voltage to 3.5kV at a rate of 1kV / s; Maintain pressure for 5 minutes and monitor leakage current (threshold ≤ 10mA); Test at a voltage value = 3.5 times the rated voltage (0.6 / 1kV) (simulation of severe working conditions); 3.3、Failure determination: Breakdown (arc conduction, qualified products must be free of breakdown at power frequency 3.5kV / 5min); The leakage current suddenly increases by more than 10mA.

[0053] The test data of the above three performance tests are shown in Table 3.

[0054] Table 3. Cable performance test

[0055] As shown in Table 3, compared with Comparative Example 1, the aluminum core of Example 1 provides mechanical support and reduces material by 30%. Compared with Comparative Example 2, Example 1 can ensure that more than 95% of the current is conducted in the copper layer (the resistance of the aluminum core of Example 1 is ≈108% of the pure copper core of Comparative Example 1), and the high-frequency resistivity is greatly reduced. Compared with Comparative Example 2, the copper layer (tensile strength ≥ 200 MPa) in the copper-clad aluminum structure of Example 1 compensates for the weakness of the aluminum core (strength 80 MPa), thereby increasing the overall strength by 120%. Compared with Example 1, Comparative Example 3 lacks a lubricating layer, and the copper-silicone interface may be easily peeled due to deformation differences, causing partial discharge (the breakdown voltage of Comparative Example 3 decreases by 16%). Comparing Example 1 with Comparative Example 4, Vi-BN and Vi-PDMS were embedded in the silica gel network (chemical bonding) through the hydrosilylation reaction, and the BN sheet (hydroxyl density 12-15 / nm 2 ) provides directional lubrication, which can reduce friction loss (the deformation rate of comparative example 3 increases by 133%), while the interface bonding between the vinyl-free silicone and BN in comparative example 4 is weak, and the deformation rate is the highest; Compared with Comparative Example 5, the paraffin-based filler of Example 1 provides phase change paraffin to absorb deformation energy, nano-Al2O3 enhances filler stiffness, and the deformation rate is reduced by 67%. At the same time, phase change energy absorption can improve thermal conductivity, and high-frequency resistivity is also reduced. Under the condition of skin depth constraint (δ=9.3mm), when the copper layer thickness of Example 1 is ≥0.2mm (>δ / 46), 98% of the current flows in the copper layer, while the thickness of Comparative Example 6 is insufficient, and the contribution of the aluminum core increases; Among them, Comparative Example 7 cracked after thermal cycling, indicating that the paraffin wax had no wrapping and was prone to local bulging when heated, resulting in reduced performance in all aspects.

[0056] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A tensile-resistant, environmentally friendly and energy-saving cable, characterized in that: The cable core (1) comprises, from the inside to the outside, a cable core (1), a winding shielding layer (2), an insulating layer (3) and a sheath (4); the cable core (1) is formed by twisting a plurality of independent wire cores (101); the wire core (101) comprises, from the inside to the outside, an aluminum core (101A), a copper sheath (101B), a modified BN lubricating layer (101C) and an insulating sheath (101D); and paraffin-based fillers (5) are filled between adjacent wire cores (101); The modified BN lubricating layer (101C) is formed by mixing vinyl-modified BN and vinyl polydimethylsiloxane in a weight ratio of 1.8-2.3:1; The synthesis steps of the vinyl-modified BN are as follows: S01, h-BN is dispersed in concentrated nitric acid aqueous solution and subjected to BN hydroxylation pretreatment to obtain hydroxylated BN with a hydroxyl density of 12-15 / nm 2 ; S02, using anhydrous toluene, deionized water, and triethylamine to perform silane hydrolysis activation on KH-570 to obtain a hydrolyzed silane solution; S03, performing a silane grafting reaction using hydroxylated BN and a hydrolyzed silane solution to obtain a reaction solution; S04. Post-treating and purifying the reaction solution to obtain vinyl-modified BN.

2. The stretch-resistant, environmentally friendly and energy-saving cable according to claim 1, characterized in that: S01 specifically comprises: dispersing 20gh-BN in 200ml of concentrated nitric acid aqueous solution with a weight concentration of 65%, refluxing at 80°C for 6 hours, centrifuging, washing with deionized water until neutral, and vacuum drying to obtain hydroxylated BN; S02 specifically includes: under nitrogen protection, dissolving 5g KH-570 in 100ml anhydrous toluene; adding 0.5ml deionized water dropwise, stirring for 30min; adding 0.1g triethylamine, reacting at 40℃ for 2h, to obtain a hydrolyzed silane solution: S03 specifically includes: under nitrogen protection, adding 10g of hydroxylated BN to the hydrolyzed silane solution, ultrasonically dispersing for 30min, heating to 110°C, and reflux reaction for 8h to obtain a reaction solution; S04 specifically includes: cooling the reaction solution to room temperature, collecting the solid by centrifugation; ultrasonically washing with toluene and ethanol three times in sequence to remove physically adsorbed silane; and vacuum drying at 60° C. for 12 hours to obtain vinyl-modified BN.

3. The stretch-resistant, environmentally friendly and energy-saving cable according to claim 1, characterized in that: The winding shielding layer (2) is spirally wrapped with a conductive polyimide tape.

4. The stretch-resistant, environmentally friendly and energy-saving cable according to claim 1, characterized in that: The insulating layer (3) is made of PVC rubber, and aramid ropes (301) are distributed in an annular shape inside the insulating layer (3).

5. The stretch-resistant, environmentally friendly and energy-saving cable according to claim 1, characterized in that: The sheath (4) is cross-linked polyethylene.

6. The stretch-resistant, environmentally friendly and energy-saving cable according to claim 1, characterized in that: The paraffin-based filler (5) is prepared by mixing paraffin, expanded graphite and nano-alumina in a weight ratio of 10:1-2:1-2.

7. The stretch-resistant, environmentally friendly and energy-saving cable according to claim 1, characterized in that: The insulating skin (101D) is made of silicone rubber, and the insulating skin (101D) is prepared from the following raw materials: vinyl silicone rubber, polyvinyl silicone rubber, hydrogen-containing silicone oil, platinum (0)-1,3-diethylene-1,1,3,3-tetramethyldisiloxane, and 1-ethynylcyclohexanol; The vinyl silicone rubber is a long-chain polysiloxane with vinyl short-circuits at both ends of the macromolecular chain, in the form of solid rubber, with a molecular weight of 300,000-400,000 and a vinyl content of 0.02-0.03 mmol vinyl / g vinyl silicone rubber; The polyvinyl silicone rubber is a long-chain polysiloxane with vinyl short-circuits at both ends or side chains of the macromolecular chain, and is in the form of solid rubber with a molecular weight of 300,000-400,000 and a vinyl content of 2-3 mmol vinyl / g polyvinyl silicone rubber. The hydrogen-containing silicone oil is polydimethyl silicone oil with Si-H bonds, and the hydrogen content is 4-6 mmol / g.

8. The method for preparing a tensile-resistant, environmentally friendly and energy-saving cable according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1, preparing a single-strand wire core; S2. Heat the raw materials of paraffin-based filler at 60℃ to form a paste, apply it to the outside of the cable core, and then bundle multiple single-strand cores in a concentric twisted manner with a twisting pitch ≤ 15 times the outer diameter of the cable core. After the twisted cable core bundle passes through a cylindrical through hole to make it round, it is cooled to obtain a paraffin-coated cable core; S3. Spirally wrap the conductive polyimide tape around the paraffin-coated cable core to form a tape shielding layer; S4. Extruding PVC rubber outside the shielding layer to form an insulating layer, wherein aramid rope is pre-placed in the die of the extruder and evenly distributed in a ring shape inside the insulating layer. The extrusion temperature is 160-180°C and cooled to set the shape; S5. Extruding cross-linked polyethylene on the outside of the insulation layer at an extrusion temperature of 120-140°C, and then vulcanizing at 180°C for 30 minutes to obtain a sheath; S6. Cool the sheath to room temperature in a water cooling tank, reel it up by tension control, and cut off the irregular end section to obtain an energy-saving cable.

9. The method for preparing a tensile-resistant, environmentally friendly and energy-saving cable according to claim 8, characterized in that: S1 specifically includes: S101, drawing the electrical grade aluminum rod to the designed diameter, cutting it into fixed length aluminum wire, polishing the surface, removing the oxide layer, and obtaining the aluminum core; S102, using a continuous extrusion cladding process to form a copper sheath on the aluminum core, with the copper layer thickness controlled to be 15-25% of the radius of the aluminum core; electroplating a nickel layer on the outer surface of the copper sheath; S103, vinyl-modified BN and vinyl polydimethylsiloxane are mixed in a weight ratio of 1.8-2.3:1, stirred into a uniform slurry, and formed into a thin layer on the surface of the copper sheath by dipping or spraying, and pre-cured at 80° C. for 5 minutes to obtain a modified BN lubricating layer; S104. Mix the insulation sheath raw materials at 40-50°C to form an extrusion material, extrude it onto the modified BN lubricating layer, and pre-vulcanize it at 120-130°C for 10 minutes to allow the hydrogen-containing silicone oil to penetrate into the BN layer and cross-link. Then, infrared vulcanize it at 200±5°C for 20 minutes to form a silicone / BN reinforced structure to obtain a single-strand wire core.

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