High-weather-resistant aerial cable and preparation method thereof

Abstract

The invention discloses a high-weather-resistance aerial cable and a preparation method thereof, belongs to the technical field of cable preparation, and is used for solving the technical problem that the weather resistance and wear resistance of an aerial cable in the prior art need to be further improved. The high-weather-resistance aerial cable specifically comprises a cable core, a wrapping layer, an armor layer and a sheath layer which are sequentially arranged from inside to outside; and the sheath layer comprises the following components in parts by weight: 60-80 parts of modified polyurethane, 5-9 parts of a modified filler and 1-3 parts of an auxiliary additive. According to the invention, the sheath layer with high flexibility, aging resistance and high strength is constructed by taking the double-dynamic covalent modified polyurethane as a matrix and the cerium-based silica composite modified filler as a reinforcing component, so that not only is the weather resistance of the aerial cable improved, but also the wear resistance of the aerial cable is improved.

Description

Technical Field

[0001] This invention relates to the field of cable manufacturing technology, specifically to a high weather-resistant high-altitude cable and its manufacturing method. Background Technology

[0002] With the rapid development of high-altitude power transmission, aerospace, and special communication equipment, higher requirements are being placed on the weather resistance, abrasion resistance, and mechanical stability of the outer sheath materials of high-altitude cables. Conventional high-altitude cable sheaths are mostly made of materials such as polyvinyl chloride (PVC), cross-linked polyethylene (XLPE), polyurethane (PU), fluoroplastics (such as FEP, PTFE), or thermoplastic elastomers (TPE). These materials have good flexibility and certain aging resistance. To improve their weather resistance and abrasion resistance, common modification methods include: introducing ultraviolet absorbers and antioxidants into the matrix; using inorganic fillers for reinforcement or carbon-based fillers to improve the heat resistance and mechanical stability of the material; in addition, some studies have also tried adding lubricating agents or carbon-based flame retardant systems to the sheath to improve the service life of the cable under high-altitude friction, ultraviolet and ozone environments.

[0003] Currently, in modification systems mainly based on physical blending or ordinary filler reinforcement, fillers are prone to agglomeration and poor interfacial bonding, resulting in limited improvement in mechanical properties and wear resistance, and even material embrittlement. UV absorbers and antioxidants are mostly small molecules, which are prone to migration and failure during high-temperature extrusion or long-term service, causing the weather resistance of the sheath to deteriorate. Although chemical crosslinking modification can improve thermal stability, it often sacrifices the flexibility and recyclability of the material. On the other hand, strong ultraviolet radiation, low air pressure and temperature difference cycling in high-altitude environments will accelerate the breakage of polymer main chains and surface pulverization. Traditional static crosslinking networks cannot achieve stress release and self-repair. Conventional sheath materials are difficult to balance between high strength, high flexibility and long service life. Poor interfacial bonding, insufficient resistance to ultraviolet aging and accumulation and propagation of microcracks are the fundamental reasons for their performance degradation and short service life.

[0004] To address this technical deficiency, a solution is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a high-weather-resistant high-altitude cable and its preparation method, in order to solve the technical problem that the weather resistance and wear resistance of high-altitude cables in the prior art need to be further improved.

[0006] The objective of this invention can be achieved through the following technical solution: a high weather-resistant high-altitude cable, comprising a cable core, a wrapping layer, an armor layer and a sheath layer arranged sequentially from the inside to the outside;

[0007] The sheath layer comprises the following components by weight: 60-80 parts modified polyurethane, 5-9 parts modified filler, and 1-3 parts auxiliary additives.

[0008] The modified polyurethane is prepared by: using hydroxyl-terminated polybutadiene and polytetrahydrofuran as hard segments, and reacting them with the hard segment diphenylmethane diisocyanate in the presence of tetrahydrofuran, followed by chain extension by Schiff base monomer and 4-hydroxymethylphenylboronic acid to obtain the modified polyurethane.

[0009] Furthermore, the modified polyurethane is prepared by the following steps:

[0010] A1. Place p-hydroxybenzaldehyde and ethanol in a reaction vessel and stir. Add 3,3'-dimethyl-4,4-diaminodicyclohexylmethane and reflux for 4-6 hours. After post-treatment, obtain Schiff base monomer.

[0011] The reaction formula for the preparation of Schiff base monomers is as follows:

[0012]

[0013] The reaction principle for the preparation of Schiff base monomers is as follows:

[0014] During the reaction, p-hydroxybenzaldehyde and 3,3'-dimethyl-4,4-diaminodicyclohexylmethane undergo a condensation reaction under ethanol reflux to form a bis-Schiff base structure, yielding a Schiff base monomer that retains the p-phenolic hydroxyl group. The mass spectrometry data of the Schiff base monomer are: m / z: 406.14 (100.0%), 407.14 (30.3%), 408.14 (4.7%).

[0015] A2. Hydroxyl-terminated polybutadiene, polytetrahydrofuran, tetrahydrofuran and dibutyltin dilaurate are placed in a reaction vessel under nitrogen atmosphere and stirred. Diphenylmethane diisocyanate is added. The reaction vessel is heated to 55-65℃ and kept at this temperature for 2-4 hours to obtain a prepolymer solution.

[0016] A3. Place the prepolymer liquid in a nitrogen-protected reactor and stir. Heat the reactor to 65-75℃, add Schiff base monomer, and keep it at the temperature for 2-4 hours. Add 4-hydroxymethylphenylboronic acid and keep it at the temperature for 2-4 hours. Post-treatment yields modified polyurethane.

[0017] The preparation reaction formula for modified polyurethane is:

[0018]

[0019] In the formula: ,

[0020] , .

[0021] The preparation principle of modified polyurethane is as follows:

[0022] During the reaction, under the catalysis of dibutyltin dilaurate, hydroxyl-terminated polybutadiene and polytetrahydrofuran undergo an addition reaction with the terminal isocyanate groups of diphenylmethane diisocyanate through their hydroxyl groups, resulting in a prepolymer liquid containing isocyanate-terminated prepolymers. Further, at 65-75℃, the isocyanate groups of the prepolymer form urea bonds with the hydroxyl groups of the Schiff base monomers, and finally the residual isocyanate groups are terminated with the primary alcohol of 4-hydroxymethylphenylboronic acid, with the borate groups fixed to the side chains, to obtain modified polyurethane.

[0023] Further, in step A1, the ratio of p-hydroxybenzaldehyde, ethanol and 3,3'-dimethyl-4,4-diaminodicyclohexylmethane is 4-6g:40-60mL:2-4g. The post-processing step includes: after the reaction is completed, the reaction system is cooled to room temperature, filtered, and the filter cake is transferred to an oven at 50-60℃ and dried to constant weight to obtain Schiff base monomer.

[0024] Furthermore, in step A2, the ratio of the amount of hydroxyl-terminated polybutadiene, polytetrahydrofuran, and dibutyltin dilaurate is 4-6g:2-4g:80-100mL:0.2-0.4g, and the molar amount of diphenylmethane diisocyanate is 0.55 times the total molar amount of hydroxyl-terminated polybutadiene and polytetrahydrofuran.

[0025] Furthermore, in step A3, the ratio of the prepolymer solution, Schiff base monomer, and 4-hydroxymethylphenylboronic acid is 30-50 mL: 2-4 g: 1-2 g. The post-processing steps include: after the reaction is completed, heating the reactor to 90-100°C and distilling under reduced pressure until no liquid is collected to obtain modified polyurethane.

[0026] Furthermore, the modified filler is prepared by the following steps:

[0027] B1. 2-[2-hydroxy-3,5-bis(1,1-dimethylpropylphenyl)]-2H-benzotriazole and acetone were placed in a reaction vessel, stirred evenly, and cerium-based nanotubes were added. The mixture was then vacuum-loaded to obtain the modified filler precursor.

[0028] B2. Place the modified filler precursor, ethanol, deionized water and ammonia in a reaction vessel and stir. Heat the reaction vessel to 35-45℃, slowly add tetraethyl orthosilicate, and keep the reaction at this temperature for 4-6 hours. The modified filler is then obtained after post-treatment.

[0029] The preparation principle of modified fillers is as follows:

[0030] During the reaction, 2-[2-hydroxy-3,5-bis(1,1-dimethylpropylphenyl)]-2H-benzotriazole is a UV absorber with strong UV absorption capacity and a phenolic hydroxyl-nitrogen heterocyclic conjugated structure. Its molecule contains hydroxyl and nitrogen atoms that can form hydrogen bonds and coordination bonds with the hydroxyl groups on the surface of cerium-based metal oxide nanotubes. When dissolved in acetone and added to cerium-based nanotubes, the solution is fully permeated into the nanotube pores and surface active sites through vacuum loading, promoting the adsorption or coordination of benzotriazole molecules on the surface of cerium dioxide nanotubes. Further, the modified filler... After the precursor is mixed with ethanol, water and ammonia, the ammonia acts as a catalyst to promote the sol-gel reaction of tetraethyl orthosilicate. Tetraethyl orthosilicate undergoes hydrolysis under alkaline conditions to generate silanol, which then forms a -Si-O-Si- network through a condensation reaction. A silicon oxide coating layer is then deposited in situ on the cerium-based nanotubes. This thin coating layer can stabilize the organic layer of benzotriazole, preventing its loss or decomposition under high temperature or light conditions. At the same time, it forms a strong Ce-O-Si bond with the cerium oxide surface, improving the structural stability and interfacial compatibility of the filler, and finally obtaining the modified filler.

[0031] Furthermore, in step B1, the ratio of 2-[2-hydroxy-3,5-bis(1,1-dimethylpropylphenyl)]-2H-benzotriazole, acetone and cerium nanotubes is 0.5-1g:40-60mL:1-2g;

[0032] Furthermore, the preparation method of the modified filler precursor is as follows: 2-[2-hydroxy-3,5-bis(1,1-dimethylpropylphenyl)]-2H-benzotriazole and acetone are placed in a reaction vessel and stirred evenly. Cerium-based nanotubes are added, and the reaction system is connected to a vacuum system. The pressure is gradually reduced to -0.06±0.03MPa, and the mixture is stirred under vacuum for 1-2 hours. After the vacuum treatment is completed, the pressure is slowly restored to normal, and the mixture is stirred for 10-15 minutes to make the system fully homogeneous. Then, the mixture is dried under reduced pressure at 50-60℃ for 4-6 hours to remove residual solvent and obtain a modified filler precursor with uniform surface loading.

[0033] Further, in step B2, the ratio of the modified filler precursor, ethanol, deionized water, ammonia, and tetraethyl orthosilicate is 2-4g:40-60mL:4-6mL:1-2mL:6-12mL, and the concentration of ammonia is 95-98wt%. The post-treatment steps include: after the reaction is completed, the reaction system is cooled to room temperature, filtered, the filter cake is washed 2-4 times with deionized water and ethanol, transferred to an oven at 50-60℃, and dried to constant weight to obtain the modified filler.

[0034] Furthermore, the cerium-based nanotubes are prepared by the following steps:

[0035] C1. Place cerium nitrate hexahydrate, urea and deionized water in a reaction vessel and stir. Heat the reaction vessel to 75-85℃ and keep it at that temperature for 20-24 hours. After post-treatment, obtain the cerium-based precursor.

[0036] C2. Place the cerium-based precursor, sodium hydroxide, and deionized water in a reaction vessel and perform a hydrothermal reaction for 10-12 hours. After post-treatment, cerium-based nanotubes are obtained.

[0037] The preparation principle of cerium-based nanotubes is as follows:

[0038] During the reaction, at 75-85℃, urea slowly hydrolyzes to generate ammonia and carbon dioxide. Ammonia further reacts with water to generate hydroxide ions, creating a slow-release alkaline environment within the system. In this slow-release process, trivalent cerium ions gradually hydrolyze and precipitate to form cerium hydroxide precursors. Simultaneously, carbon dioxide dissolves to form carbonate ions, participating in complexation and controlling the formation rate and morphological evolution of crystal nuclei. By controlling the temperature and time, cerium-based precursors with good dispersibility and uniform particle size can be obtained. Furthermore, the cerium-based precursors are subjected to hydrothermal reaction in a high-concentration sodium hydroxide solution. Under certain conditions, hydroxide ions in the system induce a preferential dissolution-recrystallization process in the crystals, promoting the self-assembly of the precursor from a plate-like structure to a tubular morphology. During this process, trivalent and tetravalent cerium ions on the surface rearrange through oxygen bridges to form cerium dioxide nanosheets with a layered plate-like structure. Under alkaline high-temperature conditions, the dissolution rate at the edge of the plate is greater than that in the central region, causing it to curl and gradually self-roll into hollow nanotubes. Finally, after washing and drying, cerium-based nanotubes with good crystallinity, high specific surface area, and oxygen vacancies with coexisting trivalent and tetravalent cerium ions on the surface can be obtained.

[0039] Further, in step C1, the ratio of cerium nitrate hexahydrate, urea, and deionized water is 2-4 g: 6-8 g: 150-170 mL. The post-processing steps include: after the reaction is complete, the reaction system is cooled to room temperature, filtered, the filter cake is washed 2-4 times with deionized water and ethanol, transferred to an oven at 50-60°C, and dried to constant weight to obtain the cerium-based precursor; in step C2, the ratio of the cerium-based precursor, sodium hydroxide, and deionized water is 0.2-0.4 g: 10-12 g: 40-60 mL, the hydrothermal reaction temperature is 110-120°C, and the post-processing steps include: after the reaction is complete, the reaction system is cooled to room temperature, filtered, the filter cake is washed 2-4 times with deionized water and ethanol, transferred to an oven at 50-60°C, and dried to constant weight to obtain cerium-based nanotubes.

[0040] This invention proposes a method for preparing a high-weather-resistant high-altitude cable, comprising the following steps:

[0041] S1. Several conductors twisted together are arranged in parallel, and insulation material is wrapped around the outside of the cable cores. Filler is placed in the gaps, and the cable cores are wrapped together with wrapping tape to form a wrapping layer.

[0042] S2. The metal wire is spirally wound around the outside of the wrapping layer to obtain the armor layer;

[0043] S3. The modified polyurethane, modified filler and auxiliary additives are mixed and added to a twin-screw extruder and melt-mixed for 8 minutes. The mixture is then extruded and coated onto the outside of the armor layer to form a sheath layer, thus obtaining the high-altitude cable.

[0044] Furthermore, in step S1, the cable core includes several parallel-arranged electrical cores and spaced filler material. The electrical core consists of a conductor and an insulating material covering the conductor. The wrapping layer is obtained by wrapping the cable core with wrapping tape. The conductor is an aluminum alloy, the insulating material is one or more of ethylene propylene rubber and cross-linked polyethylene, the filler is one or more of polyethylene foam, polypropylene fiber rope and cotton yarn, and the wrapping tape is polyester tape.

[0045] Furthermore, in step S2, the armor layer is formed by spirally winding metal wire around the outside of the wrapping layer, and the metal wire is one or more of galvanized steel wire, galvanized steel wire, and stainless steel wire;

[0046] Further, in step S3, the auxiliary additive is composed of plasticizer, lubricant and flame retardant in a mass ratio of 4:3:2. The plasticizer is one or more of dibutyl phthalate, diisononyl phthalate and dioctyl sebacate. The lubricant is one or more of oleamide, paraffin wax and polyethylene wax. The flame retardant is one or more of aluminum hydroxide, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and triphenyl phosphate.

[0047] The twin-screw extruder has eight temperature zones from the feed inlet to the discharge outlet, with temperatures of 150℃, 150℃, 165℃, 165℃, 175℃, 175℃, 185℃, and 185℃ respectively. The main motor speed of the twin-screw extruder is 120-160 rpm, and the pressure is 80-120 bar.

[0048] The present invention has the following beneficial effects:

[0049] 1. This invention obtains a cerium-based precursor by homogeneous precipitation reaction of cerium nitrate and urea at 85°C, followed by hydrothermal treatment of the precursor in sodium hydroxide solution to form a hollow structure, thus obtaining cerium-based nanotubes. The reversible trivalent and tetravalent cerium ions of cerium dioxide in the cerium-based nanotubes possess red oxygen cycling and oxygen vacancies, which can efficiently scavenge free radicals and inhibit the thermo-oxidative and ozone aging of high-altitude cable sheaths. The pores are loaded with 2-[2-hydroxy-3,5-di(1,1-dimethylpropylphenyl)]-2H-benzo[…]. Triazole achieves sustained release, long-term absorption of UVA / UVB and reduced migration. The silica thin-layer coating brings excellent dispersion and interface enhancement, enhancing the load transfer, crack resistance and wear resistance of the modified filler and polyurethane matrix. At the same time, the rigid skeleton of cerium-based nanotubes can improve the melt strength and extrusion stability during extrusion coating. The finished layer is dense and uniform. Under high-altitude strong UV, diurnal temperature difference and wind and sand erosion environment, the tensile strength of the cable decreases less, improving the weather resistance of high-altitude cables and significantly extending their service life.

[0050] 2. This invention also involves the aldehyde-amine condensation reaction of 3,3'-dimethyl-4,4-diaminodicyclohexylmethane and p-hydroxybenzaldehyde to generate a Schiff base compound containing a C=N structure. This Schiff base monomer is then introduced into the polyurethane backbone as a chain extender, resulting in reversible imine bonds in the modified polyurethane molecule. Further, modified polyurethane is prepared using hydroxyl-terminated polybutadiene and polytetrahydrofuran as soft segments, diphenylmethane diisocyanate as hard segments, the Schiff base monomer as a chain extender, and 4-hydroxymethylphenylboronic acid as a capping agent. The addition of 4-hydroxymethylphenylboronic acid allows the B(OH)2 group in its molecule to form a BOC-type borate bond with the isocyanate group. These two dynamic bonds synergistically construct a polyurethane network with reversible crosslinking. The imine bonds dominate self-healing and thermal stability, while the borate bonds... The bonding enhances toughness and environmental adaptability, enabling the material to possess both aging resistance and self-healing capabilities in high-altitude environments. This significantly improves the cable's abrasion resistance and mechanical strength. Simultaneously, the Schiff base monomer, a chain extender, introduces alicyclic and aromatic dual structures into the modified polyurethane chain. The alicyclic structure effectively improves the defects of traditional aromatic polyurethanes, such as yellowing and breakage under UV irradiation, enhancing the cable's weather resistance stability in high-altitude environments. Furthermore, the blending of polytetrahydrofuran and hydroxyl-terminated polybutadiene constructs a flexible-hard phase control system. Polytetrahydrofuran imparts excellent low-temperature flexibility and ozone resistance, while hydroxyl-terminated polybutadiene provides high polarity and molecular chain regularity, improving the compatibility of the polyurethane with the inorganic modified filler interface, thereby enhancing the interfacial bonding and mechanical strength of the cable material.

[0051] 3. The modified polyurethane and modified filler prepared in this invention form a dynamic toughness matrix and an inorganic-organic synergistic reinforcement composite system in the sheath. The polyurethane constructs a reversible cross-linked network through imine bonds and borate ester bonds, which can achieve chain segment recombination and crack self-healing under wind vibration, bending and thermal shock, maintaining high elongation at break and fatigue life. Its soft segments provide low-temperature flexibility, and the urethane hydrogen bond domains of the hard segments provide strength and creep resistance. The modified filler is composed of cerium-based nanotubes, benzotriazole and in-situ hydrolyzed silicon-oxygen network. The high specific surface area and rigid skeleton of the nanotubes realize stress transfer and crack deflection. Cerium element catalyzes carbonization to suppress smoke and increase carbon content. The Si-O-Si shell formed by tetraethyl orthosilicate improves dispersion and interfacial adhesion. Benzotriazole strongly absorbs UV and removes free radicals, significantly slowing down photo-oxidative aging. The coupling of the two makes the matrix-filler interface more stable, and micro-damage is promptly passivated by the dynamic network, thereby significantly extending the service life and safety of high-altitude cables in the combined environment of strong UV, humid cold and wind load. Attached Figure Description

[0052] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0053] Figure 1 This is a schematic diagram of the overall cross-sectional structure of the present invention.

[0054] In the diagram: 100, cable core; 101, conductor; 102, insulation material; 103, filler; 200, wrapping layer; 300, armor layer; 400, sheath layer. Detailed Implementation

[0055] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0056] The hydroxyl-terminated polybutadiene used in this invention was purchased from Hubei Xinyuhong Biomedical Technology Co., Ltd., with product number xyh001 and product name hydroxyl-terminated 1,3-butadiene homopolymer, with a molecular weight of 1800-3000.

[0057] The polytetrahydrofuran used in this invention was purchased from Shandong Yaojia Chemical Co., Ltd., under the brand name Yaojia, with a density of 0.89 g / cm³. 3 The molecular weight is 1000-1400;

[0058] The commercially available polyurethane used in this invention was purchased from Lanqiao Plastic Raw Materials Business Department in Zhangmutou City, Dongguan City. The grade is C80A and the brand is BASF, Germany.

[0059] Example 1

[0060] This embodiment provides a method for preparing cerium-based nanotubes used in modified fillers for high-weather-resistant high-altitude cables, including the following steps:

[0061] Step I: Preparation of cerium-based precursors

[0062] Weigh 20g of cerium nitrate hexahydrate, 60g of urea and 1500mL of deionized water and place them in a reaction vessel and stir. Heat the reaction vessel to 75℃ and keep it at that temperature for 20h. After the reaction is complete, wait for the reaction system to cool to room temperature, filter it, wash the filter cake twice with deionized water and ethanol, transfer it to an oven at 50℃ and dry it to constant weight to obtain the cerium-based precursor.

[0063] Step II: Preparation of cerium-based nanotubes

[0064] Weigh 2g of cerium-based precursor, 100g of sodium hydroxide and 400mL of deionized water and place them in a reaction vessel. React hydrothermally at 110℃ for 10h. After the reaction is complete, wait for the reaction system to cool to room temperature, filter, wash the filter cake twice with deionized water and ethanol, transfer it to an oven at 50℃ and dry it to constant weight to obtain cerium-based nanotubes.

[0065] Example 2

[0066] This embodiment provides a method for preparing cerium-based nanotubes used in modified fillers for high-weather-resistant high-altitude cables, including the following steps:

[0067] Step I: Preparation of cerium-based precursors

[0068] Weigh out 30g of cerium nitrate hexahydrate, 70g of urea and 1600mL of deionized water and place them in a reaction vessel and stir. Heat the reaction vessel to 80℃ and keep it at that temperature for 22h. After the reaction is complete, wait for the reaction system to cool to room temperature, filter it, wash the filter cake three times with deionized water and ethanol, transfer it to an oven at 55℃ and dry it to constant weight to obtain the cerium-based precursor.

[0069] Step II: Preparation of cerium-based nanotubes

[0070] Weigh out 3g of cerium-based precursor, 110g of sodium hydroxide and 500mL of deionized water and place them in a reaction vessel. React hydrothermally at 115℃ for 11h. After the reaction is complete, wait for the reaction system to cool to room temperature, filter, wash the filter cake three times with deionized water and ethanol, transfer it to an oven at 55℃ and dry it to constant weight to obtain cerium-based nanotubes.

[0071] Example 3

[0072] This embodiment provides a method for preparing cerium-based nanotubes used in modified fillers for high-weather-resistant high-altitude cables, including the following steps:

[0073] Step I: Preparation of cerium-based precursors

[0074] Weigh out 40g of cerium nitrate hexahydrate, 80g of urea and 1700mL of deionized water and place them in a reaction vessel and stir. Heat the reaction vessel to 85℃ and keep it at that temperature for 24h. After the reaction is complete, wait for the reaction system to cool to room temperature, filter it, wash the filter cake four times with deionized water and ethanol, transfer it to an oven at 60℃ and dry it to constant weight to obtain the cerium-based precursor.

[0075] Step II: Preparation of cerium-based nanotubes

[0076] Weigh 4g of cerium-based precursor, 120g of sodium hydroxide and 600mL of deionized water and place them in a reaction vessel. The reaction was carried out at 120℃ for 12h. After the reaction was completed, the reaction system was cooled to room temperature and filtered. The filter cake was washed 4 times with deionized water and ethanol and transferred to an oven at 60℃ and dried to constant weight to obtain cerium-based nanotubes.

[0077] Example 4

[0078] This embodiment provides a method for preparing modified filler for high weather resistance high-altitude cables, including the following steps:

[0079] Step ①: Preparation of modified filler precursor

[0080] Weigh 5g of 2-[2-hydroxy-3,5-bis(1,1-dimethylpropylphenyl)]-2H-benzotriazole and 400mL of acetone and place them in a reaction vessel. Stir until homogeneous. Add 10g of cerium-based nanotubes prepared in Example 1. Connect the reaction system to a vacuum system and gradually reduce the pressure to -0.09MPa. Maintain the vacuum state and stir for 1h. After the vacuum treatment is completed, slowly restore the atmospheric pressure and continue stirring for 10min to make the system fully homogeneous. Then, dry the mixture under reduced pressure at 50℃ for 4h to remove residual solvent and obtain the modified filler precursor.

[0081] Step 2: Preparation of modified filler

[0082] Weigh 20g of the modified filler precursor, 400mL of ethanol, 40mL of deionized water and 10mL of 95wt% ammonia water and place them in a reaction vessel and stir. Heat the reaction vessel to 35℃ and slowly add 60mL of tetraethyl orthosilicate. Keep the reaction at this temperature for 4h. After the reaction system cools to room temperature, filter it. Wash the filter cake twice with deionized water and ethanol, transfer it to an oven at 50℃ and dry it to constant weight to obtain the modified filler.

[0083] Example 5

[0084] This embodiment provides a method for preparing modified filler for high weather resistance high-altitude cables, including the following steps:

[0085] Step ①: Preparation of modified filler precursor

[0086] Weigh 7.5 g of 2-[2-hydroxy-3,5-bis(1,1-dimethylpropylphenyl)]-2H-benzotriazole and 500 mL of acetone and place them in a reaction vessel. Stir until homogeneous. Add 15 g of cerium-based nanotubes prepared in Example 2. Connect the reaction system to a vacuum system and gradually reduce the pressure to -0.06 MPa. Maintain the vacuum state and stir for 1.5 h. After the vacuum treatment is completed, slowly restore the atmospheric pressure and continue stirring for 12 min to make the system fully homogeneous. Then, dry the mixture under reduced pressure at 55 °C for 5 h to remove residual solvent and obtain the modified filler precursor.

[0087] Step 2: Preparation of modified filler

[0088] Weigh 30g of the modified filler precursor, 500mL of ethanol, 50mL of deionized water and 15mL of 96wt% ammonia water and place them in a reaction vessel and stir. Heat the reaction vessel to 40℃ and slowly add 90mL of tetraethyl orthosilicate. Keep the reaction at this temperature for 5h. After the reaction system cools to room temperature, filter it. Wash the filter cake three times with deionized water and ethanol, transfer it to an oven at 55℃ and dry it to constant weight to obtain the modified filler.

[0089] Example 6

[0090] This embodiment provides a method for preparing modified filler for high weather resistance high-altitude cables, including the following steps:

[0091] Step ①: Preparation of modified filler precursor

[0092] Weigh 10g of 2-[2-hydroxy-3,5-bis(1,1-dimethylpropylphenyl)]-2H-benzotriazole and 600mL of acetone and place them in a reaction vessel. Stir until homogeneous. Add 20g of cerium-based nanotubes prepared in Example 3. Connect the reaction system to a vacuum system and gradually reduce the pressure to -0.03MPa. Maintain the vacuum state and stir for 2h. After the vacuum treatment is completed, slowly restore the atmospheric pressure and continue stirring for 15min to make the system fully homogeneous. Then, dry the mixture under reduced pressure at 60℃ for 6h to remove residual solvent and obtain the modified filler precursor.

[0093] Step 2: Preparation of modified filler

[0094] Weigh 40g of the modified filler precursor, 600mL of ethanol, 60mL of deionized water and 20mL of 98wt% ammonia water and place them in a reaction vessel and stir. Heat the reaction vessel to 45℃ and slowly add 120mL of tetraethyl orthosilicate. Keep the reaction at this temperature for 6h. After the reaction system cools to room temperature, filter it. Wash the filter cake 4 times with deionized water and ethanol, transfer it to an oven at 60℃ and dry it to constant weight to obtain the modified filler.

[0095] Example 7

[0096] This embodiment provides a method for preparing modified polyurethane for high-weather-resistant high-altitude cables, including the following steps:

[0097] Step (1): Preparation of Schiff base monomers

[0098] Weigh 40g of p-hydroxybenzaldehyde and 400mL of ethanol and place them in a reaction vessel and stir. Add 20g of 3,3'-dimethyl-4,4-diaminodicyclohexylmethane and reflux for 4h. After the reaction is complete, wait for the reaction system to cool to room temperature, filter, and transfer the filter cake to an oven at 50℃ to dry to constant weight to obtain the Schiff base monomer.

[0099] Step 2: Preparation of prepolymer solution

[0100] Weigh out 40g of hydroxyl-terminated polybutadiene, 20g of polytetrahydrofuran, 800mL of tetrahydrofuran, and 2g of dibutyltin dilaurate and place them in a nitrogen-protected reactor and stir. Add diphenylmethane diisocyanate at 0.55 times the total molar amount of hydroxyl-terminated polybutadiene and polytetrahydrofuran. Heat the reactor to 55℃ and keep it at that temperature for 2 hours to obtain the prepolymer solution.

[0101] Step (3): Preparation of modified polyurethane

[0102] Weigh 300 mL of prepolymer solution and place it in a nitrogen-protected reactor and stir. Heat the reactor to 65°C, add 2 g of Schiff base monomer, and keep the reaction temperature for 2 h. Add 10 g of 4-hydroxymethylphenylboronic acid and keep the reaction temperature for 2 h. After the reaction is complete, heat the reactor to 90°C and distill under reduced pressure until no liquid is collected to obtain modified polyurethane.

[0103] Example 8

[0104] This embodiment provides a method for preparing modified polyurethane for high-weather-resistant high-altitude cables, including the following steps:

[0105] Step (1): Preparation of Schiff base monomers

[0106] Weigh out 50g of p-hydroxybenzaldehyde and 500mL of ethanol and place them in a reaction vessel and stir. Add 30g of 3,3'-dimethyl-4,4-diaminodicyclohexylmethane and reflux for 5h. After the reaction is complete, wait for the reaction system to cool to room temperature, filter, and transfer the filter cake to an oven at 55℃ to dry to constant weight to obtain the Schiff base monomer.

[0107] Step 2: Preparation of prepolymer solution

[0108] Weigh out 50g of hydroxyl-terminated polybutadiene, 30g of polytetrahydrofuran, 900mL of tetrahydrofuran, and 3g of dibutyltin dilaurate and place them in a nitrogen-protected reactor and stir. Add diphenylmethane diisocyanate at 0.55 times the total molar amount of hydroxyl-terminated polybutadiene and polytetrahydrofuran. Heat the reactor to 60℃ and keep it at that temperature for 3 hours to obtain the prepolymer solution.

[0109] Step (3): Preparation of modified polyurethane

[0110] Weigh 400 mL of the prepolymer solution and place it in a nitrogen-protected reactor and stir. Heat the reactor to 70°C, add 30 g of Schiff base monomer, and keep the reaction temperature for 3 h. Add 15 g of 4-hydroxymethylphenylboronic acid and keep the reaction temperature for 3 h. After the reaction is complete, heat the reactor to 95°C and distill under reduced pressure until no liquid is collected to obtain the modified polyurethane.

[0111] Example 9

[0112] This embodiment provides a method for preparing modified polyurethane for high-weather-resistant high-altitude cables, including the following steps:

[0113] Step (1): Preparation of Schiff base monomers

[0114] Weigh 60g of p-hydroxybenzaldehyde and 600mL of ethanol and place them in a reaction vessel and stir. Add 40g of 3,3'-dimethyl-4,4-diaminodicyclohexylmethane and reflux for 6h. After the reaction is complete, wait for the reaction system to cool to room temperature, filter, and transfer the filter cake to an oven at 60℃ to dry to constant weight to obtain the Schiff base monomer.

[0115] Step 2: Preparation of prepolymer solution

[0116] Weigh out 60g of hydroxyl-terminated polybutadiene, 40g of polytetrahydrofuran, 1000mL of tetrahydrofuran, and 4g of dibutyltin dilaurate and place them in a nitrogen-protected reactor and stir. Add diphenylmethane diisocyanate at 0.55 times the total molar amount of hydroxyl-terminated polybutadiene and polytetrahydrofuran. Heat the reactor to 65℃ and keep it at that temperature for 4 hours to obtain the prepolymer solution.

[0117] Step (3): Preparation of modified polyurethane

[0118] Weigh 500 mL of the prepolymer solution and place it in a nitrogen-protected reactor and stir. Heat the reactor to 75°C, add 40 g of Schiff base monomer, and keep the reaction temperature for 4 h. Add 20 g of 4-hydroxymethylphenylboronic acid and keep the reaction temperature for 4 h. After the reaction is complete, heat the reactor to 100°C and distill under reduced pressure until no liquid is collected to obtain the modified polyurethane.

[0119] Example 10

[0120] This embodiment provides a method for preparing a high-weather-resistant high-altitude cable, including the following steps:

[0121] Step 1: Preparation of the cladding layer

[0122] Several conductors 101 are stranded together and arranged in parallel. Insulation material 102 is wrapped around the outside of the cable cores, and filler material 103 is placed in the gaps. The cable cores 100 are wrapped together with wrapping tape to form a wrapping layer 200.

[0123] Step 2: Prepare the armor layer

[0124] The metal wire is spirally wound around the outside of the wrapping layer 200 to obtain the armor layer 300.

[0125] Step 3: Prepare high-altitude cables

[0126] Dibutyl phthalate, paraffin wax and aluminum hydroxide were mixed evenly in a mass ratio of 4:3:2 to obtain an auxiliary additive, which was then set aside.

[0127] Weigh out 60 parts by weight of the modified polyurethane prepared in Example 7, 5 parts by weight of the modified filler prepared in Example 4, and 1 part by weight of the auxiliary additive, mix them in a twin-screw extruder, melt mix for 8 minutes, and then extrude the mixture to cover the outside of the armor layer 300 to form the sheath layer 400, thus obtaining the high-altitude cable.

[0128] The twin-screw extruder has eight temperature zones with temperatures ranging from the feed inlet to the discharge outlet: 150°C, 150°C, 165°C, 165°C, 175°C, 175°C, 185°C, and 185°C. The main motor speed of the twin-screw extruder is 120 rpm, and the pressure is 80 bar.

[0129] Example 11

[0130] This embodiment provides a method for preparing a high-weather-resistant high-altitude cable, including the following steps:

[0131] Step 1: Preparation of the cladding layer

[0132] Several conductors 101 are stranded together and arranged in parallel. Insulation material 102 is wrapped around the outside of the cable cores, and filler material 103 is placed in the gaps. The cable cores 100 are wrapped together with wrapping tape to form a wrapping layer 200.

[0133] Step 2: Prepare the armor layer

[0134] The metal wire is spirally wound around the outside of the wrapping layer 200 to obtain the armor layer 300.

[0135] Step 3: Prepare high-altitude cables

[0136] Dibutyl phthalate, paraffin wax and aluminum hydroxide were mixed evenly in a mass ratio of 4:3:2 to obtain an auxiliary additive, which was then set aside.

[0137] Weigh out 70 parts by weight of the modified polyurethane prepared in Example 8, 6.5 parts by weight of the modified filler prepared in Example 5, and 2 parts by weight of the auxiliary additives. Mix them in a twin-screw extruder, melt mix for 8 minutes, and then extrude them to coat the outside of the armor layer 300 to form the sheath layer 400, thus obtaining the high-altitude cable.

[0138] The twin-screw extruder has eight temperature zones with temperatures ranging from the feed inlet to the discharge outlet: 150°C, 150°C, 165°C, 165°C, 175°C, 175°C, 185°C, and 185°C. The main motor speed of the twin-screw extruder is 140 rpm, and the pressure is 100 bar.

[0139] Example 12

[0140] This embodiment provides a method for preparing a high-weather-resistant high-altitude cable, including the following steps:

[0141] Step 1: Preparation of the cladding layer

[0142] Several conductors 101 are stranded together and arranged in parallel. Insulation material 102 is wrapped around the outside of the cable cores, and filler material 103 is placed in the gaps. The cable cores 100 are wrapped together with wrapping tape to form a wrapping layer 200.

[0143] Step 2: Prepare the armor layer

[0144] The metal wire is spirally wound around the outside of the wrapping layer 200 to obtain the armor layer 300.

[0145] Step 3: Prepare high-altitude cables

[0146] Dibutyl phthalate, paraffin wax and aluminum hydroxide were mixed evenly in a mass ratio of 4:3:2 to obtain an auxiliary additive, which was then set aside.

[0147] Weigh out 80 parts by weight of the modified polyurethane prepared in Example 9, 9 parts by weight of the modified filler prepared in Example 6, and 3 parts by weight of the auxiliary additives. Mix them in a twin-screw extruder, melt mix for 8 minutes, and then extrude them to cover the outside of the armor layer 300 to form the sheath layer 400, thus obtaining the high-altitude cable.

[0148] The twin-screw extruder has eight temperature zones with temperatures ranging from the feed inlet to the discharge outlet: 150°C, 150°C, 165°C, 165°C, 175°C, 175°C, 185°C, and 185°C. The main motor speed of the twin-screw extruder is 160 rpm, and the pressure is 120 bar.

[0149] Comparative Example 1

[0150] The difference between this comparative example and Example 12 is that, in step three, when preparing the high-altitude cable, the modified filler precursor is used to replace the modified filler in equal amounts.

[0151] Comparative Example 2

[0152] The difference between this comparative example and Example 12 is that the Schiff base monomer was omitted in step (3) when preparing the modified polyurethane.

[0153] Comparative Example 3

[0154] The difference between this comparative example and Example 12 is that, in step three, when preparing the high-altitude cable, commercially available polyurethane is used in an equal amount to replace the modified polyurethane.

[0155] Performance testing:

[0156] The tensile strength and elongation at break of the high-altitude cable specimens prepared in Examples 10-12 and Comparative Examples 1-3 were determined in accordance with the standard XF 306.1-2007 "Flame-retardant and fire-resistant cables - Classification and requirements of plastic insulated flame-retardant and fire-resistant cables - Part 1: Flame-retardant cables".

[0157] The abrasion resistance of the high-altitude cable specimens prepared in Examples 10-12 and Comparative Examples 1-3 were determined in accordance with the standard GB / T 17737.324-2018 "Coaxial Communication Cables - Part 1-324: Mechanical Test Methods - Cable Abrasion Resistance Test".

[0158] Weathering resistance tests were conducted on the high-altitude cable specimens prepared in Examples 10-12 and Comparative Examples 1-3 in accordance with the standard GB / T 3511-2018 "Weathering Resistance of Vulcanized Rubber or Thermoplastic Rubber". The tensile strength and abrasion resistance of the high-altitude cable specimens after the weathering test were tested in accordance with XF 306.1-2007 and GB / T 17737.324-2018. The specific data are shown in Table 1.

[0159] Table 1 - Performance Test Data for Each Sample

[0160]

[0161] Data Analysis:

[0162] Comparative analysis of the data in Table 1 reveals that the high-altitude cable sample prepared in this invention exhibits a tensile strength of 21.5 MPa, an elongation at break of 254.3%, and 2521 blade-grinding cycles. After UV aging, the tensile strength decreases to 19.6 MPa, and the blade-grinding cycles reach 2457. All these data are superior to the comparative example. Therefore, this invention first prepares cerium-based nanotubes via a urea precipitation-hydrothermal method, endowing the material with excellent mechanical and thermal stability. Then, benzotriazole and tetraethyl orthosilicate are used to modify its surface, forming a structure with UV absorption and silicon-oxygen protection. The composite modified filler significantly improves the dispersibility and interfacial bonding of the cable material. Secondly, Schiff base monomers containing imine bonds and 4-hydroxymethylphenylboronic acid are introduced into the modified polyurethane synthesis, so that the system has a dual dynamic network structure of imine bonds and borate ester bonds, realizing the self-repair and stress relaxation of the material under mechanical damage and photoaging conditions. Finally, the modified polyurethane, modified filler and auxiliary additives are mixed and added to a twin-screw extruder, melt mixed for 8 minutes, and then extruded to coat the outside of the armor layer to obtain the high-altitude cable, which not only improves the weather resistance of the high-altitude cable, but also improves its wear resistance.

[0163] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A high-weather-resistant high-altitude cable, characterized in that, It includes, from the inside out, a cable core (100), a wrapping layer (200), an armor layer (300), and a sheath layer (400). The sheath layer (400) comprises the following components by weight: 60-80 parts modified polyurethane, 5-9 parts modified filler and 1-3 parts auxiliary additives; The modified polyurethane is prepared by: using hydroxyl-terminated polybutadiene and polytetrahydrofuran as hard segments, and reacting them with the hard segment diphenylmethane diisocyanate in the presence of tetrahydrofuran, followed by chain extension by Schiff base monomer and 4-hydroxymethylphenylboronic acid to obtain the modified polyurethane.

2. The high weather-resistant high-altitude cable according to claim 1, characterized in that, The modified polyurethane is prepared by the following steps: A1. Place p-hydroxybenzaldehyde and ethanol in a reaction vessel and stir. Add 3,3'-dimethyl-4,4-diaminodicyclohexylmethane and reflux for 4-6 hours. After post-treatment, obtain Schiff base monomer. A2. Hydroxyl-terminated polybutadiene, polytetrahydrofuran, tetrahydrofuran and dibutyltin dilaurate are placed in a reaction vessel under nitrogen atmosphere and stirred. Diphenylmethane diisocyanate is added. The reaction vessel is heated to 55-65℃ and kept at this temperature for 2-4 hours to obtain a prepolymer solution. A3. Place the prepolymer liquid in a nitrogen-protected reactor and stir. Heat the reactor to 65-75℃, add Schiff base monomer, and keep it at the temperature for 2-4 hours. Add 4-hydroxymethylphenylboronic acid and keep it at the temperature for 2-4 hours. Post-treatment yields modified polyurethane.

3. The high weather-resistant high-altitude cable according to claim 2, characterized in that, In step A1, the ratio of p-hydroxybenzaldehyde, ethanol, and 3,3'-dimethyl-4,4-diaminodicyclohexylmethane is 4-6g:40-60mL:2-4g; in step A2, the ratio of hydroxyl-terminated polybutadiene, polytetrahydrofuran, and tetrahydrofuran to dibutyltin dilaurate is 4-6g:2-4g:80-100mL:0.2-0.4g, and the molar amount of diphenylmethane diisocyanate is 0.55 times the total molar amount of hydroxyl-terminated polybutadiene and polytetrahydrofuran; in step A3, the ratio of prepolymer solution, Schiff base monomer, and 4-hydroxymethylphenylboronic acid is 30-50mL:2-4g:1-2g.

4. The high weather-resistant high-altitude cable according to claim 1, characterized in that, The modified filler is prepared by the following steps: B1. 2-[2-hydroxy-3,5-bis(1,1-dimethylpropylphenyl)]-2H-benzotriazole and acetone were placed in a reaction vessel, stirred evenly, and cerium-based nanotubes were added. The mixture was then vacuum-loaded to obtain the modified filler precursor. B2. Place the modified filler precursor, ethanol, deionized water and ammonia in a reaction vessel and stir. Heat the reaction vessel to 35-45℃, slowly add tetraethyl orthosilicate, and keep the reaction at this temperature for 4-6 hours. The modified filler is then obtained after post-treatment.

5. A high-weather-resistant high-altitude cable according to claim 4, characterized in that, In step B1, the ratio of 2-[2-hydroxy-3,5-bis(1,1-dimethylpropylphenyl)]-2H-benzotriazole, acetone, and cerium nanotubes is 0.5-1g:40-60mL:1-2g; in step B2, the ratio of the modified filler precursor, ethanol, deionized water, ammonia, and tetraethyl orthosilicate is 2-4g:40-60mL:4-6mL:1-2mL:6-12mL, and the concentration of ammonia is 95-98wt%.

6. A high-weather-resistant high-altitude cable according to claim 4, characterized in that, The cerium-based nanotubes were prepared by the following steps: C1. Place cerium nitrate hexahydrate, urea and deionized water in a reaction vessel and stir. Heat the reaction vessel to 75-85℃ and keep it at that temperature for 20-24 hours. After post-treatment, obtain the cerium-based precursor. C2. Place the cerium-based precursor, sodium hydroxide, and deionized water in a reaction vessel and perform a hydrothermal reaction for 10-12 hours. After post-treatment, cerium-based nanotubes are obtained.

7. A high-weather-resistant high-altitude cable according to claim 6, characterized in that, In step C1, the ratio of cerium nitrate hexahydrate, urea, and deionized water is 2-4g:6-8g:150-170mL; in step C2, the ratio of cerium-based precursor, sodium hydroxide, and deionized water is 0.2-0.4g:10-12g:40-60mL, and the hydrothermal reaction temperature is 110-120℃.

8. A method for preparing a high-weather-resistant high-altitude cable as described in any one of claims 1-7, characterized in that, Includes the following steps: S1. Several conductors (101) twisted together are arranged in parallel, and insulation material (102) is wrapped around the outside of the cable cores. Filler material (103) is placed in the gaps, and the cable cores (100) are wrapped together with wrapping tape to form a wrapping layer (200). S2. The metal wire is spirally wound around the outside of the wrapping layer (200) to obtain the armor layer (300). S3. The modified polyurethane, modified filler and auxiliary additives are mixed and added to a twin-screw extruder and melt-mixed for 8 minutes. The mixture is then extruded and coated on the outside of the armor layer (300) to form a sheath layer (400) to obtain an aerial cable.

9. A method for preparing a high-weather-resistant high-altitude cable according to claim 8, characterized in that, In step S1, the cable core (100) includes several parallel electric cores and a filler (103) with gaps between them. The electric core is composed of a conductor (101) and an insulating material (102) covering the conductor (101). The wrapping layer (200) is obtained by wrapping the cable core (100) with wrapping tape. In step S2, the armor layer (300) is formed by spirally winding metal wire around the outside of the wrapping layer (200).

Images