Aerial insulated cable

Abstract

The invention relates to the field of cables, and discloses an aerial insulated cable, a protective layer of which is prepared from the following materials: low-density polyethylene, nitrile rubber, ethylene-vinyl acetate copolymer, modified composite filler, functional additive and the like. The modified composite filler is prepared by grafting a modified silane coupling agent and Na-montmorillonite loaded titanium dioxide; the modified silane coupling agent is prepared by reacting p-hydroxybenzaldehyde with phosphorus oxychloride, then carrying out addition with DOPO (9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide), reacting the obtained product with p-aminodiphenylamine, and then carrying out substitution with 3-chloropropyltriethoxysilane; the functional additive is prepared by the following steps: reacting 3, 5-di-tert-butyl-4-hydroxybenzaldehyde with 2-amino-4-methylbenzothiazole, then adding sodium borohydride for reductive amination, substituting the obtained product with cyanuric chloride, and then reacting with N-butyl-2, 2, 6, 6-tetramethyl-4-piperidylamine, and the functional additive is prepared by the following steps: reacting 3, 5-di-tert-butyl-4-hydroxybenzaldehyde with 2-amino-4-methylbenzothiazole; and the protective layer material is endowed with good flame retardance, antibacterial property and long-acting aging resistance.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of cables, and particularly relates to an overhead insulated cable. BACKGROUND

[0002] The overhead insulated cable is a new power transmission mode between overhead conductors and underground cables, and is used in electric distribution systems or telecommunication lines. The overhead insulated cable takes a conductor as a core, and is usually provided with an insulating layer and a protective layer and other layered structures outside the conductor to ensure normal operation and safety performance of the conductor, so that the cable can reduce the erection height and improve the operation safety and reliability of the line. Therefore, the overhead insulated cable still needs to be used in large quantities in the overhead distribution line in the regions such as forest areas, hills and river channels.

[0003] The protective layer is the first barrier of the overhead insulated cable, and its performance will affect the service life of the whole cable and whether the system can normally operate. Therefore, the material for manufacturing the protective layer should have good mechanical properties, aging resistance and flame retardance, and play a good protection role. However, the overhead cable is exposed to the outdoor environment for a long time, is easily eroded by rain, ultraviolet light and thermal oxygen, and causes oxidation and degradation and other aging phenomena of the protective layer. In addition, the warm and humid environment causes the protective layer material to easily breed bacteria, corrode the cable core material, and seriously affect the use of the cable.

[0004] The prior art usually adds a large amount of inorganic flame retardant to improve the flame retardance of the cable material. However, the inorganic flame retardant has poor compatibility with the material, reduces the mechanical properties of the material, and also makes the viscosity, compatibility and flexibility of the high polymer material worse. In addition, one of the effective ways to solve the problem of ultraviolet aging in the prior art is to directly add an ultraviolet absorber to the high polymer material. However, the ultraviolet absorber with low relative molecular mass has defects in migration resistance, volatility resistance and extraction resistance, and also has poor thermal stability, which limits its application under high temperature conditions. SUMMARY

[0005] In order to solve the problems mentioned in the background, the purpose of the present application is to provide an overhead insulated cable. By introducing a modified composite filler and a functional additive, the cable material is endowed with good flame retardance, antibacterial performance, tensile properties and long-term aging resistance.

[0006] The purpose of the present application can be achieved by the following technical solutions: An aerial insulated cable, comprising a conductor, an insulation layer, a shielding layer and a protective layer arranged in sequence from inside to outside, the protective layer is prepared by extrusion equipment outside the shielding layer, the protective layer material comprises the following raw materials by weight: low density polyethylene 65~80 parts, nitrile rubber 20~30 parts, ethylene-vinyl acetate copolymer 10~25 parts, modified composite filler 5~15 parts, functional additive 2~5 parts, dicumyl peroxide 2~6 parts, triallyl isocyanurate 2~6 parts, lubricant 1~3 parts, plasticizer 1~3 parts; The modified composite filler is prepared by grafting a modified silane coupling agent onto the surface of the composite filler through a chemical reaction; the composite filler is prepared by using a sol-gel method to prepare sodium-based montmorillonite loaded with titanium dioxide; the modified silane coupling agent is prepared by substituting the prepared aldehyde-based phosphorus intermediate with DOPO through an addition reaction, then substituting the anti-aging DOPO derivative obtained by Schiff base reaction of the DOPO derivative with p-aminodiphenylamine with 3-chloropropyl triethoxysilane; The functional additive is prepared by substituting the hindered phenolic benzothiazole monomer obtained by Schiff base reaction of 3,5-di-tert-butyl-4-hydroxybenzaldehyde and 2-amino-4-methylbenzothiazole, followed by reductive amination with sodium borohydride, with cyanuric chloride to obtain a triazine derivative, which is then substituted with N-butyl-2,2,6,6-tetramethyl-4-piperidinamine.

[0007] Preferably, the preparation method of the protective layer material comprises the following steps: weighing each raw material by weight, placing low density polyethylene, nitrile rubber and ethylene-vinyl acetate copolymer into a plastic mixing mill and plasticizing for 2~3 min, then adding modified composite filler, functional additive, lubricant and plasticizer, discharging after uniform mixing at 105~110℃, then adding dicumyl peroxide and triallyl isocyanurate, and sheeting and cooling to prepare the protective layer material.

[0008] Preferably, the preparation method of the modified composite filler comprises the following steps: (1) mixing butyl titanate and anhydrous ethanol to obtain solution one, mixing deionized water and acetic acid to obtain solution two, adding sodium-based montmorillonite and deionized water to solution one after stirring for 20~30 min, adding solution two after fully stirring and mixing, stirring and mixing uniformly, then standing and aging for 20~24 h, drying and grinding, and then baking in a muffle furnace to prepare the composite filler; (2) Take p-hydroxybenzaldehyde, tetrahydrofuran and triethylamine in a reactor, stir and mix at 0°C, then add phosphorus oxychloride dropwise, stir for 2-3 h, quench with sulfuric acid and concentrate under reduced pressure, dissolve the residue in ethyl acetate, wash with water, dry over magnesium sulfate, concentrate, dissolve the residue in ethyl acetate, add petroleum ether dropwise and stir, filter and dry after white precipitate appears, to prepare an aldehyde group-containing phosphorus intermediate; (3) Take the aldehyde group-containing phosphorus intermediate, DOPO and N,N-dimethylformamide in a reactor, reflux at 80-85°C for 3-4 h, then filter, wash and dry after the reaction is completed, to prepare a DOPO derivative; (4) Take the DOPO derivative, p-aminodiphenylamine and 1,4-dioxane in a reactor, stir and react at 95-100°C for 8-12 h, then filter, wash and dry after the reaction is completed, to prepare an antioxidant DOPO derivative; (5) Take the antioxidant DOPO derivative and N,N-dimethylformamide in a reactor, then add 3-chloropropyltriethoxysilane and triethylamine dropwise, stir and react at 65-80°C for 4-6 h, then filter, rotary-evaporate and dry after the reaction is completed, to prepare a modified silane coupling agent; (6) Take the composite filler and ultrasonically disperse in anhydrous ethanol and deionized water, then add the modified silane coupling agent, stir and react at 55-70°C for 6-8 h, then filter, wash and dry after the reaction is completed, to prepare a modified composite filler.

[0009] Preferably, the calcination temperature in step (1) is 480-500°C, and the calcination time is 4-5 h.

[0010] Preferably, the molar ratio of p-hydroxybenzaldehyde to phosphorus oxychloride in step (2) is 3-3.6:1; the molar ratio of the aldehyde group-containing phosphorus intermediate to DOPO in step (3) is 1:1-1.1; and the molar ratio of the DOPO derivative to p-aminodiphenylamine in step (4) is 1:2-2.1.

[0011] Preferably, the preparation method of the functional additive comprises the following steps: A. Take 3,5-di-tert-butyl-4-hydroxybenzaldehyde, 2-amino-4-methylbenzothiazole and ethanol in a reactor, heat to 60-70°C and react for 4-5 h, then cool to below 0°C, add sodium borohydride in batches and continue to react for 0.5-1 h, then add hydrochloric acid aqueous solution to adjust the pH value to 2-3, rotary-evaporate to remove ethanol, adjust the pH value to 8-9 with sodium hydroxide aqueous solution, dry over anhydrous magnesium sulfate after extraction with dichloromethane, separate by rotary evaporation, and prepare a hindered phenolic benzothiazole monomer; B, take acetone in the reactor, ice bath cooling to 5℃ or below, add cyanuric chloride stirring uniform, slowly drop the hindered phenolic benzothiazole monomer solution, drop after 2~3h, then drop the sodium hydroxide aqueous solution, drop after 2~3h, reaction is completed after washing, filtering, drying, preparation obtained triazine derivatives; C, take triazine derivatives and m-xylene in the reactor, stirring at 0℃ uniform, then add N-butyl-2, 2, 6, 6-tetramethyl-4-piperidinamine, stirring after mixing, add sodium hydroxide, continue to react 6~7h, reaction is completed after filtering, washing, drying, preparation obtained functional additives.

[0012] Preferably, the molar ratio of 3, 5-di-tert-butyl-4-hydroxybenzaldehyde, 2-amino-4-methylbenzothiazole and sodium borohydride in step A is 1:1~1.1:0.74.

[0013] Preferably, the molar ratio of cyanuric chloride and hindered phenolic benzothiazole monomer in step B is 1:1~1.1; the molar ratio of triazine derivatives and N-butyl-2, 2, 6, 6-tetramethyl-4-piperidinamine in step C is 1:2~2.3.

[0014] Preferably, the conductor is aluminum alloy wire stranded; the insulating layer is crosslinked polyethylene material; the shielding layer is copper wire woven electromagnetic shielding net.

[0015] Preferably, the plasticizer is one or more combinations of dioctyl adipate, dimethyl phthalate, dioctyl phthalate, diisodecyl phthalate; the lubricant is one or more combinations of stearic acid, polyethylene wax, oxidized polyethylene wax.

[0016] The beneficial effects of the present application are: The present application utilizes sol-gel method to prepare the composite filler of sodium-based montmorillonite loaded with titanium dioxide, wherein the sodium-based montmorillonite has a larger specific surface area, the titanium dioxide is loaded on the surface and interlayer of the sodium-based montmorillonite, and plays an excellent mechanical performance, and the titanium dioxide as an important inorganic ultraviolet shielding agent and antibacterial agent has certain ultraviolet radiation resistance and antibacterial and mildew resistance, meanwhile, the present application prepares an anti-aging DOPO derivative containing anti-aging-NH functional groups, antibacterial Schiff base groups, two kinds of flame-retardant phosphorus oxidation states and hydroxyl groups through substitution reaction of hydroxybenzaldehyde and phosphorus oxychloride, addition reaction of aldehyde group-containing phosphorus intermediates and DOPO, Schiff base reaction of DOPO derivatives and antioxidant p-aminodiphenylamine, then substitution reaction of 3-chloropropyl triethoxysilane and hydroxyl groups in the anti-aging DOPO derivative is used to prepare a modified silane coupling agent, and then the silicon hydroxyl groups in the modified silane coupling agent are grafted on the surface of the composite filler through dehydration condensation reaction, so as to prepare a modified composite filler, which promotes the relatively uniform dispersion of the composite filler in the matrix material, is beneficial to the full play of the mechanical performance, and through the firm chemical bond grafting of the modified silane coupling agent, the migration and precipitation problems of the functional components in the modified silane coupling agent in the long-term use or later processing process are avoided, and the long-term heat-resistant oxygen aging, antibacterial and flame-retardant properties of the cable material are endowed.

[0017] The present application utilizes Schiff base reaction of 3,5-di-tert-butyl-4-hydroxybenzaldehyde and 2-amino-4-methylbenzothiazole, and then substitution reaction of sodium borohydride to reduce unstable C=N double bond into stable C-N single bond to generate secondary amine groups, to prepare hindered phenolic benzothiazole monomer containing antioxidant hindered phenolic structure and antibacterial benzothiazole structure, then substitution reaction of secondary amine groups in the hindered phenolic benzothiazole monomer and one chlorine atom in cyanuric chloride is used to prepare triazine derivative, and then substitution reaction of secondary amine groups in hindered amine light stabilizer N-butyl-2,2,6,6-tetramethyl-4-piperidinamine and the remaining two ungrafted chlorine atoms in the triazine derivative is used to prepare functional additive, the functional additive contains triazine ring structure with good thermal stability and anti-ultraviolet light stability, and the combination of the triazine ring structure and the hindered amine functional group plays excellent ultraviolet absorption performance, increases the density of the hindered amine functional group and the relative molecular mass, endows the cable material with good ultraviolet aging resistance, and the introduced antioxidant hindered phenolic structure and antibacterial benzothiazole structure can endow the cable material with good heat-resistant oxygen aging resistance and antibacterial performance, and broaden the functional application of the functional additive. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0019] The preparation method of the modified composite filler in Embodiment 1 comprises the following steps: (1) 7 mL of butyl titanate and 7 mL of anhydrous ethanol are mixed to obtain solution one, 5 mL of deionized water and 5 mL of acetic acid are mixed to obtain solution two, 2 g of sodium-based montmorillonite and 50 mL of deionized water are added to solution one after stirring for 30 min, and then solution two is added dropwise after being fully stirred and mixed uniformly, and then the mixture is left to stand for 24 h, and then the mixture is dried and ground, and then the mixture is placed in a muffle furnace and calcined at 500 DEG C for 4 h to prepare a composite filler; (2) 4.4 g of p-hydroxybenzaldehyde, 50 mL of tetrahydrofuran and 5 mL of triethylamine are placed in a reactor, and then the mixture is stirred and mixed at 0 DEG C, and then 0.93 mL of phosphorus oxychloride is added dropwise, and then the mixture is stirred for 2 h, and then the mixture is quenched with 0.1 mol / L sulfuric acid and concentrated under reduced pressure, and then the residue is dissolved in 30 mL of ethyl acetate, and then the mixture is washed with water, and then the mixture is dried over magnesium sulfate, and then the mixture is concentrated, and then 5 mL of ethyl acetate is added to dissolve the residue, and then 20 mL of petroleum ether is added dropwise and stirred, and then a white precipitate is obtained, and then the mixture is filtered and dried to prepare an aldehyde group-containing phosphorus intermediate; (3) 4.1 g of the aldehyde group-containing phosphorus intermediate, 2.2 g of DOPO and 50 mL of N,N-dimethylformamide are placed in a reactor, and then the mixture is refluxed at 80 DEG C for 4 h, and then the mixture is filtered, washed and dried after the reaction is completed to prepare a DOPO derivative; (4) 6.2 g of the DOPO derivative, 3.7 g of p-aminodiphenylamine and 80 mL of 1,4-dioxane are placed in a reactor, and then the mixture is stirred and reacted at 100 DEG C for 10 h, and then the mixture is filtered, washed and dried after the reaction is completed to prepare an anti-aging DOPO derivative; (5) 7.6 g of the anti-aging DOPO derivative and 100 mL of N,N-dimethylformamide are placed in a reactor, and then 2.1 g of 3-chloropropyltriethoxysilane and 1.2 mL of triethylamine are added dropwise, and then the mixture is stirred and reacted at 75 DEG C for 6 h, and then the mixture is filtered, evaporated and dried after the reaction is completed to prepare a modified silane coupling agent; (6) 2 g of the composite filler is ultrasonically dispersed in 90 mL of anhydrous ethanol and 20 mL of deionized water, and then 1.7 g of the modified silane coupling agent is added, and then the mixture is stirred and reacted at 65 DEG C for 7 h, and then the mixture is filtered, washed and dried after the reaction is completed to prepare a modified composite filler.

[0020] The preparation method of the functional additive in Embodiment 2 comprises the following steps: A, take 11.7g 3, 5-di-tert-butyl-4-hydroxybenzaldehyde, 8.3g 2-amino-4-methylbenzothiazole and 100mL ethanol in a reactor, heated to 65℃ for 5h, then cooled to 0℃ or less, batchwise addition of 1.4g sodium borohydride continue to react 0.5h, then add hydrochloric acid solution to adjust the pH value to 3, rotary evaporation to remove ethanol, using 10% sodium hydroxide solution to adjust the pH value to 8, extracted with dichloromethane after drying with anhydrous magnesium sulfate, rotary evaporation after separation, to prepare a hindered phenolic benzothiazole monomer; B, take 100mL acetone in a reactor, ice bath cooling to 5℃ or less, add 9.2g cyanuric chloride stirring uniform, slowly drop 19g hindered phenolic benzothiazole monomer acetone solution 30mL, drop after 3h, then drop 20% sodium hydroxide solution 10mL, drop after 3h, reaction is completed by washing, filtering, drying, to prepare a triazine derivative; C, take 15.8g triazine derivative and 200mL m-xylene in a reactor, stirring at 0℃ uniform, then add 12.7g N-butyl-2, 2, 6, 6-tetramethyl-4-piperidinamine, stirring after mixing, add 2.4g sodium hydroxide, continue to react 7h, reaction is completed by filtering, washing, drying, to prepare a functional additive.

[0021] Example 3 A protective layer material includes the following ingredients by weight: low density polyethylene 67 parts, nitrile rubber 21 parts, ethylene-vinyl acetate copolymer 12 parts, modified composite filler prepared in Example 1 5.7 parts, functional additive prepared in Example 2 2.2 parts, dicumyl peroxide 2.3 parts, triallyl isocyanurate 2.5 parts, lubricant stearic acid 1.2 parts, plasticizer dioctyl adipate 1.1 parts.

[0022] The preparation method of the protective layer material includes the following steps: The ingredients are weighed by weight parts, the low density polyethylene, nitrile rubber and ethylene-vinyl acetate copolymer are put into the plastic mixing machine and plasticized for 2min, then the modified composite filler, functional additive, lubricant and plasticizer are added and mixed uniformly, then discharged at 110℃, followed by adding dicumyl peroxide and triallyl isocyanurate, and the protective layer material is prepared by sheeting and cooling.

[0023] A kind of overhead insulated cable, its preparation method is: S1, the conductor is obtained by twisting not less than two aluminum alloy wires with each other; S2, the crosslinked polyethylene insulation layer is extruded on the outer surface of the conductor by using an extruder; S3, the copper wire is cross-woven on the outer surface of the insulation layer, the diameter of the copper wire is 0.2mm, and the weaving density is 90%, to obtain a shielding layer; S4, extruding a protective layer material on the outer surface of the shielding layer to obtain the overhead insulated cable.

[0024] Example 4 A protective layer material comprises the following raw materials by weight: low density polyethylene 74 parts, nitrile rubber 25 parts, ethylene-vinyl acetate copolymer 17 parts, modified composite filler prepared in Example 1 10 parts, functional additive prepared in Example 2 3.4 parts, dicumyl peroxide 4.1 parts, triallyl isocyanurate 4.5 parts, lubricant polyethylene wax 2.1 parts, plasticizer dimethyl phthalate 2.1 parts.

[0025] The preparation method of the protective layer material is the same as that in Example 3.

[0026] An overhead insulated cable, the preparation method of which is the same as that in Example 3.

[0027] Example 5 A protective layer material comprises the following raw materials by weight: low density polyethylene 78 parts, nitrile rubber 27 parts, ethylene-vinyl acetate copolymer 23 parts, modified composite filler prepared in Example 1 13 parts, functional additive prepared in Example 2 4.6 parts, dicumyl peroxide 5.2 parts, triallyl isocyanurate 5.5 parts, lubricant oxidized polyethylene wax 2.8 parts, plasticizer dioctyl phthalate 2.7 parts.

[0028] The preparation method of the protective layer material is the same as that in Example 3.

[0029] An overhead insulated cable, the preparation method of which is the same as that in Example 3.

[0030] Comparative Example 1 A preparation method of a modified composite filler comprises the following steps: (1) 7 mL of butyl titanate and 7 mL of anhydrous ethanol are mixed to obtain solution one, 5 mL of deionized water and 5 mL of acetic acid are mixed to obtain solution two, 2 g of sodium-based montmorillonite and 50 mL of deionized water are added to solution one after stirring for 30 min, and then solution two is added dropwise after being fully stirred and mixed, stirred and mixed, and then aged for 24 h, dried and ground, and then placed in a muffle furnace and calcined at 500℃ for 4 h to obtain a composite filler; (2) 4.4 g of p-hydroxybenzaldehyde, 50 mL of tetrahydrofuran, and 5 mL of triethylamine are placed in a reactor, stirred and mixed at 0℃, and then 0.93 mL of phosphorus oxychloride is added dropwise, stirred for 2 h, quenched with 0.1 mol / L sulfuric acid, and concentrated under reduced pressure, the residue is dissolved in 30 mL of ethyl acetate, washed with water, dried over magnesium sulfate, concentrated, the residue is dissolved in 5 mL of ethyl acetate, 20 mL of petroleum ether is added dropwise and stirred, a white precipitate appears, and then filtered and dried to obtain an aldehyde group-containing phosphorus intermediate; (3) Take 4.1 g of aldehyde-based phosphorus-containing intermediate, 2.2 g of DOPO and 50 mL of N,N-dimethylformamide in a reactor, and reflux at 80°C for 4 h. After the reaction is completed, the product is prepared by filtration, washing and drying. (4) Take 5 g of DOPO derivative and 100 mL of N,N-dimethylformamide in a reactor, then add 2.1 g of 3-chloropropyl triethoxysilane and 1.2 mL of triethylamine, and stir at 75°C for 6 h. After the reaction is completed, the product is prepared by filtration, rotary evaporation and drying. (5) Take 2 g of composite filler and ultrasonically disperse in 90 mL of anhydrous ethanol and 20 mL of deionized water, then add 1.7 g of modified silane coupling agent, and stir at 65°C for 7 h. After the reaction is completed, the product is prepared by filtration, washing and drying.

[0031] Comparative Example 2 A protective layer material includes the following raw materials by weight: low-density polyethylene 78 parts, nitrile rubber 27 parts, ethylene-vinyl acetate copolymer 23 parts, modified composite filler prepared in Comparative Example 1 13 parts, functional additive prepared in Example 2 4.6 parts, dicumyl peroxide 5.2 parts, triallyl isocyanurate 5.5 parts, lubricant oxidized polyethylene wax 2.8 parts, plasticizer dioctyl phthalate 2.7 parts.

[0032] The preparation method of the above protective layer material is the same as that of Example 3.

[0033] An overhead insulated cable is prepared by the same method as in Example 3.

[0034] Comparative Example 3 A protective layer material includes the following raw materials by weight: low-density polyethylene 78 parts, nitrile rubber 27 parts, ethylene-vinyl acetate copolymer 23 parts, composite filler prepared in Example 1 13 parts, functional additive prepared in Example 2 4.6 parts, dicumyl peroxide 5.2 parts, triallyl isocyanurate 5.5 parts, lubricant oxidized polyethylene wax 2.8 parts, plasticizer dioctyl phthalate 2.7 parts.

[0035] The preparation method of the above protective layer material is the same as that of Example 3.

[0036] An overhead insulated cable is prepared by the same method as in Example 3.

[0037] Comparative Example 4 A protective layer material comprising the following ingredients in parts by weight: low density polyethylene 78 parts, nitrile rubber 27 parts, ethylene-vinyl acetate copolymer 23 parts, modified composite filler prepared in Example 1 13 parts, N-butyl-2,2,6,6-tetramethyl-4-piperidinamine 4.6 parts, dicumyl peroxide 5.2 parts, triallyl isocyanurate 5.5 parts, lubricant oxidized polyethylene wax 2.8 parts, plasticizer dioctyl phthalate 2.7 parts.

[0038] The protective layer material is prepared according to the method of Example 3.

[0039] An aerial insulated cable is prepared according to the method of Example 3.

[0040] Performance testing (1) The protective layer materials prepared in Examples 3-5 and Comparative Examples 2-4 are made into test samples with a size of 100 mm x 6.5 mm x 3 mm, and the limiting oxygen index of the test samples is tested according to the national standard GB / T 2406.2-2009 to evaluate the flame retardant performance of the samples. Generally, the greater the limiting oxygen index, the better the flame retardant performance, and vice versa. The antibacterial performance is tested according to QB / T 2591-2003, and the test bacteria is Staphylococcus aureus. The test results are shown in the following table:

[0041] As can be seen from the above table, the protective layer materials prepared in Examples 3-5 have good flame retardant performance and antibacterial performance. In Comparative Example 2, the modified composite filler added is not grafted with p-aminodiphenylamine antioxidant, and in Comparative Example 3, the composite filler is not modified. The bacteriostatic rates of Comparative Examples 2-3 are lower than those of Examples 3-5, because the antibacterial Schiff base group is not introduced, and the limiting oxygen index of Comparative Example 3 is lower than that of Examples 3-5, because two flame-retardant phosphorus-oxidized molecular structures are not introduced, resulting in a significant decrease in flame retardant performance. In Comparative Example 4, the functional additives are replaced with N-butyl-2,2,6,6-tetramethyl-4-piperidinamine in equal amounts, and the bacteriostatic rate is lower than that of Examples 3-5, because the antibacterial benzothiazole group is not introduced, and the limiting oxygen index is slightly lower than that of Examples 3-5, because the triazine ring structure has certain flame retardant performance.

[0042] (2) The protective layer materials prepared in Examples 3-5 and Comparative Examples 2-4 were tested for tensile properties by using a universal mechanical testing machine according to GB / T 1040.2-2022; and the change rates of tensile strength and elongation at break after aging in a 110℃ thermal-oxidative aging oven for 168h were tested to evaluate the thermal-oxidative aging resistance of the samples; and the change rates of tensile strength and elongation at break after cumulative irradiation for 72h (turning over halfway to ensure uniform irradiation) under a 40W ultraviolet lamp at 60℃ with a sample-to-lamp distance of 254mm were tested to evaluate the ultraviolet aging resistance of the samples, and the test results are shown in the following table:

[0043] As can be seen from the above table, the protective layer material prepared in Example 3-5 has high tensile strength and is not easy to break, and still has high tensile properties after thermal-oxidative aging for 168h and ultraviolet aging for 72h, and has excellent long-term thermal-oxidative aging resistance and ultraviolet aging resistance. The change rates of tensile strength and elongation at break after thermal-oxidative aging in Comparative Example 2-3 are significantly different from those in Example 3-5, which is because the grafting of p-aminodiphenylamine antioxidant improves the thermal-oxidative aging resistance of the material to some extent, and the tensile strength and elongation at break in Comparative Example 3 are slightly lower than those in Example 3-5, which may be due to the agglomeration of the composite filler, resulting in a decrease in tensile properties, and the change rates of tensile strength and elongation at break after thermal-oxidative aging and ultraviolet aging in Comparative Example 4 are significantly different from those in Example 3-5, which is because the introduction of hindered phenol structure has certain antioxidant properties, which is conducive to improving the thermal-oxidative aging resistance of the material, and the triazine ring structure has ultraviolet light stability, and the combination of hindered amine light stabilizer plays an excellent role in ultraviolet aging resistance, and the functional additives with relatively large molecular weight obtained by grafting reaction are not easy to precipitate and migrate, thereby having excellent long-term ultraviolet aging resistance.

[0044] In the description of the present specification, the description of the terms "one embodiment", "example", "specific example" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0045] The basic principles, main features and advantages of the present application are shown and described above. It should be understood by those skilled in the art that the present application is not limited by the above examples, and the above examples and descriptions in the specification are only to illustrate the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application.

Claims

1. An aerial insulated electrical cable, characterized in that, The protective layer is prepared by extruding the protective layer material outside the shielding layer through an extruding device, and the protective layer material comprises the following raw materials in parts by weight: low-density polyethylene 65-80 parts, nitrile rubber 20-30 parts, ethylene-vinyl acetate copolymer 10-25 parts, modified composite filler 5-15 parts, functional additive 2-5 parts, dicumyl peroxide 2-6 parts, triallyl isocyanurate 2-6 parts, lubricant 1-3 parts, and plasticizer 1-3 parts. The modified composite filler is prepared by grafting a modified silane coupling agent onto the surface of the composite filler through a chemical reaction; the composite filler is prepared by using a sol-gel method to prepare sodium-based montmorillonite loaded with titanium dioxide; the modified silane coupling agent is prepared by using substitution reaction of p-hydroxybenzaldehyde and phosphorus oxychloride, addition reaction of the prepared aldehyde-containing phosphorus intermediate and DOPO to prepare a DOPO derivative, and substitution reaction of the obtained anti-aging DOPO derivative and 3-chloropropyl triethoxysilane. The functional additive is prepared by Schiff base reaction of 3,5-di-tert-butyl-4-hydroxybenzaldehyde and 2-amino-4-methylbenzothiazole, subsequent addition of sodium borohydride for reductive amination to prepare a hindered phenolic benzothiazole monomer, and substitution reaction of the obtained hindered phenolic benzothiazole monomer and cyanuric chloride to prepare a triazine derivative, and further substitution reaction of the triazine derivative and N-butyl-2,2,6,6-tetramethyl-4-piperidinamine.

2. An overhead power cable according to claim 1, characterised in that The preparation method of the protective layer material comprises the following steps: weighing the raw materials according to the parts by weight, placing the low-density polyethylene, nitrile rubber and ethylene-vinyl acetate copolymer in a plasticating machine for plasticating for 2-3 min, then adding the modified composite filler, functional additive, lubricant and plasticizer, discharging after uniform mixing at 105-110°C, and then adding dicumyl peroxide and triallyl isocyanurate to prepare the protective layer material.

3. The overhead power cable of claim 1, wherein, The preparation method of the modified composite filler comprises the following steps: (1) mixing butyl titanate and anhydrous ethanol to obtain solution one, mixing deionized water and acetic acid to obtain solution two, adding sodium-based montmorillonite and deionized water to solution one after stirring for 20-30 min, adding solution two dropwise after uniform stirring, standing for 20-24 h after uniform stirring, drying and grinding, and then baking in a muffle furnace to prepare the composite filler; (2) adding p-hydroxybenzaldehyde, tetrahydrofuran and triethylamine into a reactor, stirring and mixing at 0°C, adding phosphorus oxychloride dropwise, stirring for 2-3 h, quenching with sulfuric acid and concentrating under reduced pressure, dissolving the residue in ethyl acetate, washing with water, drying with magnesium sulfate, concentrating, dissolving the residue in ethyl acetate, adding petroleum ether dropwise and stirring, filtering and drying after white precipitate appears, and preparing the aldehyde-containing phosphorus intermediate. (3) Take the aldehyde group of phosphorus-containing intermediates, DOPO and N, N-dimethylformamide in the reactor, placed at 80~85℃ under reflux reaction 3~4h, after reaction by suction filtration, washing, drying, preparation of DOPO derivatives; (4) Take DOPO derivatives, p-amino diphenylamine and 1,4-dioxane in the reactor, placed at 95~100℃ under stirring reaction 8~12h, after reaction by suction filtration, washing, drying, preparation of anti-aging DOPO derivatives; (5) Take anti-aging DOPO derivatives and N, N-dimethylformamide in the reactor, then drop 3-chloropropyl triethoxysilane and triethylamine, placed at 65~80℃ under stirring reaction 4~6h, after reaction by suction filtration, rotary evaporation, drying, preparation of modified silane coupling agent; (6) Take the composite filler ultrasonic dispersion in anhydrous ethanol and deionized water, then add modified silane coupling agent, placed at 55~70℃ under stirring reaction 6~8h, after reaction by suction filtration, washing, drying, preparation of modified composite filler.

4. An overhead power cable according to claim 3, characterised in that The calcination temperature in step (1) is 480~500℃, and the calcination time is 4~5h.

5. The overhead power cable of claim 3, wherein, The molar ratio of p-hydroxybenzaldehyde and phosphorus oxychloride in step (2) is 3~3.6:1; the molar ratio of aldehyde group of phosphorus-containing intermediates and DOPO in step (3) is 1:1~1.1; the molar ratio of DOPO derivatives and p-amino diphenylamine in step (4) is 1:2~2.

1.

6. The overhead power cable of claim 1, wherein, The preparation method of the functional additive comprises the following steps: A, take 3, 5-di-tert-butyl-4-hydroxybenzaldehyde, 2-amino-4-methylbenzothiazole and ethanol in the reactor, heated to 60~70℃ reaction 4~5h, then cooled to below 0℃, batch sodium borohydride is added to continue to react 0.5~1h, then add hydrochloric acid solution to adjust the pH value to 2~3, rotary evaporation to remove ethanol, using sodium hydroxide solution to adjust the pH value to 8~9, after extraction with dichloromethane, dry with anhydrous magnesium sulfate, rotary evaporation after separation, preparation of hindered phenolic benzothiazole monomer; B, take acetone in the reactor, ice bath cooling to below 5℃, add cyanuric chloride and stir evenly, slowly drop the hindered phenolic benzothiazole monomer solution, after drop, reaction 2~3h, then drop sodium hydroxide solution, after drop, continue to react 2~3h, after reaction by washing, filtration, drying, preparation of triazine derivatives; C, take triazine derivatives and m-xylene in the reactor, stirring at 0℃, then add N-butyl-2, 2, 6, 6-tetramethyl-4-piperidinamine, stirring after mixing, add sodium hydroxide, continue to react 6~7h, after reaction by filtration, washing, drying, preparation of functional additive.

7. An overhead power cable according to claim 6, characterised in that The molar ratio of 3, 5-di-tert-butyl-4-hydroxybenzaldehyde, 2-amino-4-methylbenzothiazole and sodium borohydride in step A is 1:1~1.1:0.

74.

8. The overhead power cable of claim 6, wherein, The molar ratio of cyanuric chloride and hindered phenolic benzothiazole monomer in step B is 1:1-1.1; the molar ratio of triazine derivative and N-butyl-2,2,6,6-tetramethyl-4-piperidinamine in step C is 1:2-2.

3.

9. The overhead power cable of claim 1, wherein, The conductor is an aluminum alloy wire stranded; the insulating layer is a cross-linked polyethylene material; and the shielding layer is a copper wire woven electromagnetic shielding net.

10. The overhead power cable of claim 1, wherein, The plasticizer is one or more combinations of dioctyl adipate, dimethyl phthalate, dioctyl phthalate and diisodecyl phthalate; and the lubricant is one or more combinations of stearic acid, polyethylene wax and oxidized polyethylene wax.

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