Insulating composite material for live-line work soft sling of power transmission line and preparation method and application thereof

Abstract

The application relates to the technical field of insulating composite materials, in particular to an insulating composite material for a soft sling for live working of a power transmission line and a preparation method and application thereof. The preparation method comprises the following steps: forming a polydopamine coating layer on the surface of aramid fiber; immersing the aramid fiber with the polydopamine coating layer in a nano-material coating solution, and taking out and solidifying to obtain the insulating composite material; the nano-material coating solution comprises F-H2-Zn-MOF@SiO2 and a solvent; a soft sling for live working of a power transmission line is prepared by twisting the above-mentioned insulating composite material for a soft sling for live working of a power transmission line into a single filament, then combining the single filaments into a strand, and twisting the strand in the opposite direction of the single filament; a plurality of strands are combined into a primary rope in the reverse direction; and the primary rope is immersed in a coating solution after being stacked and arranged in an orderly manner, compacted, taken out and solidified to obtain the soft sling. The soft sling prepared by the application has excellent mechanical strength and electrical insulation performance.

Description

Technical Field

[0001] This invention relates to the field of insulating composite materials technology, and in particular to an insulating composite material for flexible slings used in live-line work on power transmission lines, its preparation method, and its application. Background Technology

[0002] Live-line work on ultra-high voltage transmission lines (such as 1000 kV AC lines) is a core means of ensuring the safe operation of the power grid and can avoid huge economic losses caused by unplanned outages. However, traditional insulated poles are not portable, and their length usually exceeds 10 meters. In addition, insulated poles can only perform simple operations (such as hanging warning signs) and cannot adapt to complex work scenarios (such as conductor repair and hardware replacement).

[0003] Flexible insulating material slings, due to their lightweight, bendable, and easy-to-carry characteristics, have become a key tool for ultra-high voltage (UHV) live-line work, replacing insulating poles for tasks such as transport, climbing, and hoisting. However, existing sling materials (such as silk ropes and nylon ropes) have limitations such as insufficient insulation performance and low mechanical strength, failing to meet the composite performance requirements of UHV operations, including anti-slip, wear-resistant, and cut-resistant properties. Summary of the Invention

[0004] The purpose of this invention is to address the aforementioned shortcomings of the prior art by proposing an insulating composite material for flexible slings used in live-line work on power transmission lines, its preparation method, and its application.

[0005] The first objective of this invention is to provide a method for preparing an insulating composite material for flexible slings used in live-line work on power transmission lines, wherein a polydopamine coating is formed on the surface of aramid fibers;

[0006] Aramid fibers with a polydopamine coating are immersed in a nanomaterial coating solution, and then removed and cured to obtain the insulating composite material.

[0007] The nanomaterial coating solution comprises F-H2-Zn-MOF@SiO2 and a solvent;

[0008] The preparation method of the F-H2-Zn-MOF@SiO2 is as follows:

[0009] ZIF8 was dispersed in ethanol, ammonia and tetraethyl orthosilicate were added, the reaction was stirred, centrifuged, washed and dried to obtain Zn-MOF@SiO2;

[0010] Zn-MOF@SiO2 was aminated to obtain NH2-Zn-MOF@SiO2, and then hydrophobically modified to obtain F-H2-Zn-MOF@SiO2.

[0011] Furthermore, in the nanomaterial coating solution, the mass-to-volume ratio of F-H2-Zn-MOF@SiO2 to the solvent is 1g:10~20ml.

[0012] Further, the specific operation of hydrophobic modification is as follows: NH2-Zn-MOF@SiO2 is dispersed in toluene, heptadecyltrimethoxysilane is added, and the mixture is refluxed at 100~130 °C for 12~24 h; centrifugation, washing, and drying are performed to obtain F-NH2-Zn-MOF@SiO2; the mass-volume ratio of NH2-Zn-MOF@SiO2, toluene, and heptadecyltrimethoxysilane is 1 g: 50~100 ml: 1~3 ml.

[0013] Further, the specific steps for amylating Zn-MOF@SiO2 are as follows: Zn-MOF@SiO2 is dispersed in toluene, and then 3-aminopropyltrimethoxysilane is added. The mixture is refluxed at 100~130 °C for 12~24 h, and then centrifuged, washed, and dried to obtain NH2-Zn-MOF@SiO2.

[0014] A second objective of this invention is to provide an insulating composite material for flexible slings used in live-line work on transmission lines, prepared by the method described above.

[0015] The second objective of this invention is to provide a flexible sling for live-line work on transmission lines. The aforementioned flexible sling for live-line work on transmission lines is formed by twisting an insulating composite material into monofilaments, which are then combined into strands with the strands twisted in the opposite direction to the monofilaments. Multiple strands are twisted in the opposite direction to form a primary rope. The primary ropes are stacked neatly on top of each other, compacted, and then immersed in a coating solution before being removed and cured to obtain the flexible sling.

[0016] In this process, F-NH2-Zn-MOF@SiO2 is dispersed in acetone, and then epoxy resin and diethylenetriamine curing agent are added. The mixture is stirred for 2-5 hours to obtain the coating solution.

[0017] Furthermore, the mass-to-volume ratio of F-NH2-Zn-MOF@SiO2, epoxy resin, diethylenetriamine, and acetone is 1:20~30:3~5:50~100.

[0018] Furthermore, the specific curing operation is as follows: the rope is pre-cured at 60~80℃ for 2~5 hours, and then cured at 120~150℃ for 3~6 hours to obtain a soft sling.

[0019] Furthermore, the insulating composite material used for the soft slings for live-line work on transmission lines is twisted with a twist of 10-15 twists / 10 cm to form monofilaments; 12-16 twisted monofilaments are combined into strands with the twist direction opposite to that of the monofilaments; 30-50 strands are twisted in the opposite direction to form a primary rope with a diameter of 3-5 mm, and the twist is controlled at 8-10 twists / 10 cm.

[0020] Furthermore, the soft suspenders are immersed in an isopropanol solution containing 2-3 wt% fluorocarbon resin and then dried to obtain a soft suspender with a hydrophobic protective layer.

[0021] The purpose of this invention is to address the problems of insufficient insulation performance and low mechanical strength of existing sling materials used for live-line work on power transmission lines. It provides an insulating composite material for live-line work on power transmission lines that combines high insulation performance and excellent mechanical strength. The invention employs a solvothermal method to synthesize F-NH2-Zn-MOF@SiO2 nanoparticles with a core-shell structure. Dopamine self-polymerization modification technology is used to enhance the surface activity of aramid fibers, achieving uniform composite of nanoparticles and fibers, forming a three-dimensional interpenetrating network structure of "fiber-nanoparticle-resin". The F-NH2-Zn-MOF@SiO2 core-shell structure acts as an inorganic insulating layer, effectively dispersing the electric field and blocking moisture penetration. Simultaneously, the energy dissipation mechanism of the mesoporous channels alleviates stress concentration. Finally, an epoxy resin coating layer is formed to create a soft sling. The bonding between the nanoparticles and the epoxy resin matrix forms a three-dimensional interpenetrating network structure of "fiber-nanoparticle-resin", which significantly improves the interfacial shear strength (up to 15 MPa), achieving simultaneous enhancement of mechanical and insulation properties.

[0022] The soft sling prepared by this invention has a tensile strength of 520 MPa, which is 40% higher than that of traditional materials, and a leakage current of <0.5 mA under 1100 kV high voltage, exhibiting both excellent mechanical strength and electrical insulation properties. Its core-shell structure, with a SiO2 shell layer (dielectric constant of approximately 3.9), effectively disperses the electric field and blocks moisture penetration. Combined with a fluorocarbon hydrophobic modification layer, this ensures the material maintains long-term stability in complex live-line working environments, significantly extending tool life and reducing operational risks. Attached Figure Description

[0023] Figure 1 A schematic diagram illustrating a method for manufacturing an insulating composite material for a flexible sling used in live-line work on power transmission lines;

[0024] Figure 2 This is a SEM image of F-NH2-Zn-MOF@SiO2 prepared in Example 1;

[0025] Figure 3 The nitrogen adsorption-desorption curve of F-NH2-Zn-MOF@SiO2 prepared in Example 1 is shown.

[0026] Figure 4 SEM image of the F-NH2-Zn-MOF@SiO2 / aramid fiber insulating composite material prepared in Example 1;

[0027] Figure 5 The stress-strain curves are for the F-NH2-Zn-MOF@SiO2 / aramid fiber insulating composite material prepared in Example 1. Detailed Implementation

[0028] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0029] Example 1

[0030] The process for preparing a flexible sling for live-line working on transmission lines is as follows: Figure 1 As shown.

[0031] 1. Preparation of nano-F-NH2-Zn-MOF@SiO2

[0032] 1.47 g of Zn(NO3)2·6H2O was dissolved in 50 mL of MeOH and labeled as solution A. 3.24 g of 2-methylimidazole was dissolved in 50 mL of methanol and labeled as solution B. Solution B was rapidly poured into solution A under vigorous stirring, and the reaction was allowed to proceed at room temperature for 24 h. The white precipitate was collected by centrifugation, washed three times with MeOH, and dried at 60 ℃ for 12 h to obtain Zn-MOF nanoparticles.

[0033] 0.5 g Zn-MOF was dispersed in 100 mL ethanol and sonicated for 30 min. 5 mL ammonia and 2 mL tetraethyl orthosilicate were added, and the mixture was stirred at 30 °C for 6 h. The product was collected by centrifugation, washed three times with ethanol, and dried at 60 °C for 12 h to obtain Zn-MOF@SiO2 core-shell nanomaterials.

[0034] 1 g of Zn-MOF@SiO2 was dispersed in 50 mL of toluene and sonicated for 30 min. 1 mL of 3-aminopropyltrimethoxysilane was added, and the mixture was refluxed at 110 °C for 12 h. The product was collected by centrifugation, rinsed three times with toluene and EtOH ethanol, and dried at 60 °C for 12 h to obtain NH2-Zn-MOF@SiO2.

[0035] 1 g of NH2-Zn-MOF@SiO2 was dispersed in 50 mL of toluene and sonicated for 30 min. 1 mL of heptadecafluorodecyltrimethoxysilane was added, and the mixture was refluxed at 110 °C for 12 h. The product was collected by centrifugation, washed three times with toluene and ethanol, and dried at 60 °C for 12 h to obtain F-NH2-Zn-MOF@SiO2.

[0036] 2. Preparation of F-NH2-Zn-MOF@SiO2 / aramid fiber insulation composite material

[0037] First, the aramid fibers were boiled in water until the solution became clear to remove sizing agent and stains from their surface. Then, they were dried in an 80 °C oven for 12 h for later use. Next, 8 g of dopamine and the desized aramid fibers were added to 4 L of 10 mM Tris buffer (pH=8.5, adjusted with HCl), and the reaction was carried out in the dark for 24 h. Finally, the sample was rinsed with deionized water and transferred to an 80 °C oven to dry for 24 h to obtain the modified aramid fibers.

[0038] F-NH2-Zn-MOF@SiO2 was dispersed in acetone at a concentration of 1 g / 10 mL and sonicated for 15 min to obtain a homogeneous F-NH2-Zn-MOF@SiO2 solution.

[0039] An appropriate amount of modified aramid fiber was impregnated in F-NH2-Zn-MOF@SiO2 solution, sonicated for 30 min, and then dried in a vacuum oven for 12 h to obtain F-NH2-Zn-MOF@SiO2 / aramid fiber insulating composite material.

[0040] 3. Preparation of soft suspenders

[0041] 10g of F-H2-Zn-MOF@SiO2 was dispersed in 50 mL of acetone and sonicated for 15 min. 200g of epoxy resin and 30g of diethylenetriamine curing agent were added, and the mixture was stirred for 2 h to obtain the coating layer solution.

[0042] The F-NH2-Zn-MOF@SiO2 / aramid fiber insulation composite material is twisted at a twist rate of 10 twists / 10 cm. Twelve twisted monofilaments are combined into a strand with the twist direction opposite to that of the monofilaments. Thirty strands are then twisted in the opposite direction (e.g., Z-twist for the strands, S-twist for the rope) to form a primary rope with a diameter of 3 mm and a twist rate controlled at 8 twists / 10 cm. Sixteen hundred primary ropes are stacked neatly, and after being compacted using a suitable clamping device, they are immersed in a coating solution. After standing for 30 minutes, they are removed and, according to the required soft sling size (30 cm wide, 5 cm thick), pre-cured at 60-80℃ for 2-5 hours, and then cured at 120-150℃ for 3-6 hours to obtain the soft sling.

[0043] The soft suspenders were immersed in an isopropanol solution containing 2 wt% fluorocarbon resin (such as PFPE) for 5 min, and then dried at 100°C for 1 h to form a hydrophobic protective layer.

[0044] like Figure 2 As shown, regular polyhedral particles with a diameter of approximately 50-100 nm are visible at the center of the image, corresponding to the typical crystal morphology of Zn-MOF. These particles have smooth surfaces and sharp edges, forming a core-shell heterostructure. The SiO2 shell layer restricts excessive deformation of the core layer through a continuous Si-O-Si network, resulting in a progressive failure mode of "soft core-hard shell." The CN chemical bonds generated by the amination modification increase the interfacial shear strength between the nanoparticles and the epoxy resin matrix to 15 MPa (compared to only 3-5 MPa with traditional physical adsorption), significantly improving the overall strength of the composite material.

[0045] Meanwhile, the SiO2 shell, as an inorganic insulating layer, has a lower dielectric constant (approximately 3.9) than organic MOF materials (approximately 5-8), which can reduce electric field concentration and improve the withstand voltage performance of the material at 1100 kV (leakage current < 0.5 mA).

[0046] Figure 3 The nitrogen adsorption-desorption curves for F-NH2-Zn-MOF@SiO2 show its typical mesoporous structure (specific surface area up to 1150 m² / g) and uniform pore size distribution (average pore size 3.2 nm). This structure alleviates stress concentration through the energy dissipation mechanism of mesoporous channels, while the high specific surface area enhances the anchoring effect on the epoxy resin. Combined with the low dielectric properties of the SiO2 shell, it effectively disperses the electric field and blocks moisture penetration.

[0047] Figure 4 SEM image of the F-NH2-Zn-MOF@SiO2 / aramid fiber insulating composite material prepared in Example 1; Figure 4The surface of the nano-F-NH2-Zn-MOF@SiO2 modified aramid fiber is uniformly embedded with F-NH2-Zn-MOF@SiO2 particles, forming a three-dimensional interpenetrating network of "fiber-nanoparticle-resin". This structure enhances the friction between fibers through the bridging effect of nanoparticles and strengthens the resistance to deformation with the rigid support of the SiO2 shell, resulting in a significant improvement in mechanical strength. At the same time, the tightly coated nanoparticle layer forms a uniform insulating barrier, and the fluorocarbon hydrophobic modification reduces moisture adsorption.

[0048] Figure 5 The stress-strain curve of the flexible sling insulation composite material for live-line work of transmission lines prepared in Example 1 shows that its tensile strength reaches 520 MPa and its elongation at break remains at 8-10%. This is due to the fact that the core-shell structure of the nano-modified aramid fiber enhances the mechanical properties through the synergistic effect of energy dissipation and rigid support. At the same time, the tightly wrapped hydrophobic F-NH2-Zn-MOF@SiO2 layer forms a uniform insulation barrier, and the SiO2 shell with low dielectric constant effectively disperses the electric field, so that the material still maintains a low leakage current (<0.5 mA) under 1100 kV high voltage, thereby achieving simultaneous enhancement of mechanical and insulation properties.

[0049] For any points not covered above, existing technologies shall apply.

[0050] Although specific embodiments of the present invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of the invention. Those skilled in the art can make various modifications or additions to the described specific embodiments or use similar methods to replace them, without departing from the direction of the invention or exceeding the scope defined by the appended claims. Those skilled in the art should understand that any modifications, equivalent substitutions, improvements, etc., made to the above embodiments based on the technical essence of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing an insulating composite material for flexible slings used in live-line work on transmission lines, characterized in that: A polydopamine coating is formed on the surface of aramid fibers; Aramid fibers with a polydopamine coating are immersed in a nanomaterial coating solution, and then removed and cured to obtain the insulating composite material. The nanomaterial coating solution comprises F-H2-Zn-MOF@SiO2 and a solvent; The preparation method of the F-H2-Zn-MOF@SiO2 is as follows: ZIF8 was dispersed in ethanol, ammonia and tetraethyl orthosilicate were added, the reaction was stirred, centrifuged, washed and dried to obtain Zn-MOF@SiO2; Zn-MOF@SiO2 was aminated to obtain NH2-Zn-MOF@SiO2, and then hydrophobically modified to obtain F-H2-Zn-MOF@SiO2.

2. The preparation method according to claim 1, characterized in that: In the nanomaterial coating solution, the mass-to-volume ratio of F-H2-Zn-MOF@SiO2 to solvent is 1g:10~20ml.

3. The preparation method according to claim 1, characterized in that: The specific steps for hydrophobic modification are as follows: NH2-Zn-MOF@SiO2 is dispersed in toluene, heptadecafluorodecyltrimethoxysilane is added, and the mixture is refluxed at 100~130 °C for 12~24 h; centrifugation, washing, and drying are performed to obtain F-NH2-Zn-MOF@SiO2; The mass-to-volume ratio of NH2-Zn-MOF@SiO2, toluene, and heptafluorodecyltrimethoxysilane is 1g:50~100ml:1~3ml.

4. The preparation method according to claim 1, characterized in that: The specific steps for amylating Zn-MOF@SiO2 are as follows: Zn-MOF@SiO2 is dispersed in toluene, and then 3-aminopropyltrimethoxysilane is added. The mixture is refluxed at 100~130 °C for 12~24 h. After centrifugation, washing, and drying, NH2-Zn-MOF@SiO2 is obtained.

5. An insulating composite material for flexible slings used in live-line work on transmission lines, prepared by the method described in any one of claims 1-4.

6. A flexible sling for live-line working on transmission lines, characterized in that, The insulating composite material for the soft sling used for live-line work on transmission lines as described in claim 5 is twisted to form monofilaments, which are then combined into strands with the twist direction of the strands opposite to that of the monofilaments; multiple strands are twisted in opposite directions to form a primary rope; After the primary ropes are stacked neatly and compacted, they are immersed in a coating solution and then removed and cured to obtain a soft sling. In this process, F-NH2-Zn-MOF@SiO2 is dispersed in acetone, and then epoxy resin and diethylenetriamine curing agent are added and stirred for 2-5 h to obtain the coating layer solution.

7. A flexible sling for live-line working on transmission lines as described in claim 6, characterized in that, The mass-to-volume ratio of F-NH2-Zn-MOF@SiO2, epoxy resin, diethylenetriamine, and acetone is 1:20~30:3~5:50~100.

8. A flexible sling for live-line working on transmission lines as described in claim 6, characterized in that, The specific curing process is as follows: pre-cur the rope at 60~80℃ for 2~5 hours, and then cure it at 120~150℃ for 3~6 hours to obtain a soft sling.

9. A flexible sling for live-line working on transmission lines as described in claim 6, characterized in that, The insulating composite material used for flexible slings for live-line work on transmission lines is twisted into monofilaments with a twist of 10-15 twists / 10 cm; 12-16 twisted monofilaments are combined into strands with the twist direction opposite to that of the monofilaments; 30-50 strands are twisted in the opposite direction to form a primary rope with a diameter of 3-5 mm, and the twist is controlled at 8-10 twists / 10 cm.

10. A flexible sling for live-line working on transmission lines as described in claim 6, characterized in that, A soft suspender strap is immersed in an isopropanol solution containing 2-3 wt% fluorocarbon resin, then removed and dried to obtain a soft suspender strap with a hydrophobic protective layer.

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