An anti-aging aerial cable and its production process

Abstract

The present invention discloses an anti-aging overhead cable and a preparation method thereof, relating to the field of cables. The anti-aging overhead cable includes a conductor core, an insulating layer and a sheath layer from inside to outside; the insulating layer is made of cross-linked polyethylene, and the cross-linked polyethylene includes the following raw materials in parts by weight: 170-180 parts of low-density polyethylene, 10-12 parts of cross-linking agent, 8.5-10.5 parts of anti-treeing aging agent and 4-6 parts of antioxidant. The synthesized anti-treeing aging agent includes nano-magnesium oxide, benzophenone structure and terminal carbon-carbon double bond, which improves the mechanical properties, insulation properties and anti-treeing aging properties of the cable insulating layer. The synthesized antioxidant includes terminal carbon-carbon double bond, mesoporous silica, hindered phenol structure, thiophene ring and thioether group, making the cable insulating layer have persistent antioxidant aging resistance. Therefore, the anti-aging overhead cable of the present invention has excellent mechanical properties and anti-aging properties and has a long service life.

Description

Technical Field

[0001] The present invention relates to the field of cables, and particularly to an anti-aging overhead cable and its production process. Background Art

[0002] Overhead cable is a new high-voltage power transmission method between overhead conductors and underground cables, with main characteristics such as high power supply reliability, good power supply safety, convenient erection and maintenance, and reasonable economy. Overhead cables usually include overhead conductors, insulating layers, and outer protective sleeves. Common insulating layer materials include cross-linked polyethylene, polyethylene, polypropylene, ethylene-propylene rubber, and chloroprene rubber, etc. Cross-linked polyethylene insulating material is a three-dimensional network thermosetting material. Compared with polyethylene as a linear thermoplastic material, its mechanical properties and thermal stability are significantly improved.

[0003] When the cross-linked polyethylene insulating material is under the multiple actions of factors such as temperature and electric field, due to the existence of impurities, space charges are easily accumulated inside the specimen, resulting in partial discharge and the formation of electrical tree, which causes the rapid premature breakdown of the cable insulating layer. Therefore, improving the electrical resistance performance of polymer insulating materials under high temperature and high field is the key to increasing the transmission voltage level of power cables. When overhead cables are installed in high-altitude environments such as across mountains and rivers, due to mechanical stresses generated by operations such as bending and stretching of the cables, tiny cracks will form at the internal insulation, and external moisture is likely to penetrate in from the cracks and accumulate as water droplets inside the insulating material. Under the action of an alternating electric field, water trees are formed, destroying the insulating layer structure and resulting in insulation degradation. During the use of the insulating layer material of overhead cables, it ages due to the action of light, heat, and oxygen, resulting in performance degradation.

[0004] Generally, anti-tree aging agents, water tree inhibitors, antioxidants, etc. are added to the cross-linked polyethylene insulating material to improve aging phenomena such as electrical aging, water tree aging, photoaging, thermal aging, and oxygen aging of the cable. However, the dispersion compatibility of small molecule additives in the cross-linked polyethylene matrix is poor, and they are prone to migration and failure, and cannot effectively extend the service life of the cable. The patent with publication number CN105860426B discloses a preparation method and application of a cable insulating material containing nano-magnesium oxide / low-density polyethylene / modified bentonite. The prepared insulating material has high heat resistance and strength, short aging time, and can maintain non-degradation for a long time under high temperature and high pressure. However, the disadvantage is that the surface of nano-magnesium oxide is hydrophilic and oleophobic, prone to agglomeration, and has poor compatibility with the polyethylene matrix. Previous studies have shown that nano-magnesium oxide is of great significance for improving the dielectric strength and improving the distribution of space charges. Therefore, it is necessary to improve the surface properties of nano-magnesium oxide to make it more uniformly dispersed in the matrix and improve the comprehensive performance of the cross-linked polyethylene insulating material. Summary of the Invention

[0005] To solve the above technical problems, the present invention provides an anti-aging overhead cable and its production process.

[0006] The object of the present invention can be achieved by the following technical solutions:

[0007] An anti-aging overhead cable, including a conductor core, an insulating layer, and a sheath layer from the inside out; the conductor core is composed of several aluminum alloy wires stranded together, the sheath layer is made of TPE sheath material; the insulating layer is made of cross-linked polyethylene, and the cross-linked polyethylene includes the following raw materials in parts by weight: 170-180 parts of low-density polyethylene, 10-12 parts of cross-linking agent, 8.5-10.5 parts of tree aging-resistant agent, and 4-6 parts of antioxidant; the cross-linking agent is benzoyl peroxide;

[0008] The preparation of the anti-aging overhead cable includes the following steps:

[0009] Step S1: Put the low-density polyethylene into a rheometer for melt blending, mix it at 105-110 °C and a rotation speed of 50 r / min for 4-6 min, then add the tree aging-resistant agent and the cross-linking agent, mix for another 3 min, add the antioxidant, and finally mix for 10-15 min to obtain cross-linked polyethylene;

[0010] Step S2: Stranded the aluminum alloy wires to form a conductor core, extrude and deposit the cross-linked polyethylene on the outer periphery of the conductor core with an extruder to form an insulating layer; then extrude and deposit the TPE sheath material on the outer periphery of the insulating layer to obtain a sheath layer, and perform annealing treatment after extrusion to obtain the anti-aging overhead cable.

[0011] The preparation of the tree aging-resistant agent includes the following steps:

[0012] Step A1: Add nano-magnesium oxide to toluene, ultrasonically disperse for 40 min, add erucic acid and N,N'-dicyclohexylcarbodiimide under stirring, heat up to 110-120 °C for constant temperature reflux stirring for 48-51 h, then centrifuge for 10-15 min, centrifuge the lower layer precipitate with absolute ethanol, and finally vacuum dry the lower layer precipitate at 80 °C for 12 h to obtain modified magnesium oxide;

[0013] Further, the dosage ratio of nano-magnesium oxide, toluene, erucic acid, and N,N'-dicyclohexylcarbodiimide is 5-7 g: 120 mL: 10 g: 2 g;

[0014] During the reaction process of Step A1, the hydroxyl groups on the surface of nano-magnesium oxide react with erucic acid to generate nano-magnesium oxide with unsaturated alkane long chains on the surface, that is, modified magnesium oxide;

[0015] Step A2: Add the modified magnesium oxide into dichloromethane, start stirring, then add 3-chloroperbenzoic acid, and stir and react at room temperature for 4 - 5 h to obtain the epoxy product; in a nitrogen atmosphere, add 3-benzoylbenzoic acid and toluene into a flask, heat up to 45 °C, add pyridine, start stirring, add the epoxy product into the flask, stir and react for 8 - 10 h, then heat up to 110 - 120 °C and stir for 1 - 2 h to obtain the hydroxyl product;

[0016] Further, the dosage ratio of the modified magnesium oxide, dichloromethane and 3-chloroperbenzoic acid is 12 - 16 g : 180 - 190 mL : 0.5 - 1.0 mol; the dosage ratio of 3-benzoylbenzoic acid, toluene, pyridine and the epoxy product is 25 - 30 g : 100 - 110 mL : 0.2 - 0.25 mol : 13 - 15 g;

[0017] During the reaction process of Step A2, the unsaturated double bonds on the surface of the modified magnesium oxide are oxidized into epoxy groups to obtain the epoxy product; the carboxyl group of 3-benzoylbenzoic acid undergoes a ring-opening reaction with the epoxy group of the epoxy product to obtain the hydroxyl product;

[0018] Step A3: Add the hydroxyl product, pyridine, triethylamine and dimethyl sulfoxide into a flask to obtain mixture a, and add acryloyl chloride into dimethyl sulfoxide to obtain mixture b. Under an ice-water bath at 0 °C, slowly drip mixture b into mixture a. After the dripping is completed, heat up to 40 °C and keep the temperature constant for reaction for 8 - 10 h, then perform reduced-pressure distillation to prepare the anti-treeing aging agent;

[0019] Further, the dosage ratio of the hydroxyl product, pyridine, triethylamine and dimethyl sulfoxide is 14 - 16 g : 0.01 - 0.015 mol : 0.5 - 1.0 mol : 70 - 80 mL; the dosage ratio of acryloyl chloride and dimethyl sulfoxide is 4.5 - 5.4 g : 20 - 30 mL; the dosage ratio of mixture a and mixture b is 75 - 85 mL : 25 - 35 mL;

[0020] During the reaction process of Step A3, the hydroxyl group of the hydroxyl product reacts with acryloyl chloride to generate the anti-treeing aging agent containing terminal carbon-carbon double bonds.

[0021] The preparation of the antioxidant includes the following steps:

[0022] Step B1: In a nitrogen atmosphere, add 5-methylthiophene-2-carbaldehyde and acetic anhydride into a reaction flask, start reflux stirring, heat up to 150 - 170 °C, then add potassium carbonate, and keep the temperature constant for reflux stirring and reaction for 24 - 26 h, perform extraction, rotary evaporation and drying to obtain the unsaturated carboxylic acid; add the unsaturated carboxylic acid into DMF, start stirring, slowly add thionyl chloride, heat up to 40 - 50 °C, and keep the temperature constant for stirring and reaction for 4 - 5 h, filter, extract and dry to obtain the acyl chloride product;

[0023] Further, the dosage ratio of 5-methylthiophene-2-carbaldehyde, acetic anhydride, and potassium carbonate is 0.1 mol: 0.05 - 0.07 mol: 5 - 8 mmol; the dosage ratio of unsaturated carboxylic acid, DMF, and thionyl chloride is 0.1 mol: 90 mL: 0.1 - 0.15 mol;

[0024] During the reaction process of step B1, the aldehyde group of 5-methylthiophene-2-carbaldehyde reacts with acetic anhydride to form an unsaturated carboxylic acid containing a carbon-carbon double bond; the unsaturated carboxylic acid reacts with thionyl chloride to form an acyl chloride product;

[0025] Step B2: Add 3,5-di-tert-butyl-4-hydroxybenzyl alcohol, pyridine, triethylamine, and dimethyl sulfoxide into a flask to obtain mixture 1, and then add the above acyl chloride product into dimethyl sulfoxide to obtain mixture 2. Under an ice bath at 0 °C, slowly dropwise add mixture 2 into mixture 1. After the addition is complete, raise the temperature to 40 °C and keep the temperature constant for reaction for 8 - 10 h, and then perform vacuum distillation to obtain compound s;

[0026] Further, the dosage ratio of 3,5-di-tert-butyl-4-hydroxybenzyl alcohol, pyridine, triethylamine, and dimethyl sulfoxide is 0.1 mol: 0.01 - 0.015 mol: 0.1 mol: 80 - 90 mL; the dosage ratio of the acyl chloride product and dimethyl sulfoxide is 0.1 mol: 100 - 110 mL; the dosage ratio of mixture 1 and mixture 2 is 85 - 95 mL: 105 - 115 mL;

[0027] During the reaction process of step B2, the hydroxyl group of 3,5-di-tert-butyl-4-hydroxybenzyl alcohol reacts with the acyl chloride of the acyl chloride product to form compound s containing a hindered phenol, thioether, and thiophene ring structure;

[0028] Step B3: Add compound S to acetone, stir at room temperature for 10 - 20 min to obtain a mixture, then add carboxyl-functionalized hollow mesoporous silica, stir at room temperature for 2 - 2.5 h, evacuate for 30 min, then let in air for 15 min, repeat the steps of evacuation and letting in air three times, wash with ethanol and deionized water, dry, and grind to obtain the loaded product;

[0029] Further, the dosage ratio of compound S, acetone, and carboxyl-functionalized hollow mesoporous silica is 43 - 45 g: 430 - 450 mL: 20 - 25 g;

[0030] During the reaction process of step B3, under a vacuum environment, the mixture formed by compound s and acetone can overcome the "barrier" at the ports of carboxyl-functionalized hollow mesoporous silica under the action of van der Waals forces, and compound s thus enters the interior of the mesoporous silica to obtain the loaded product;

[0031] Step B4: Add the supported product into DMF, start stirring, slowly add thionyl chloride, heat up to 40 - 50 °C, stir and react at a constant temperature for 4 - 5 h, then filter, extract and dry to obtain acyl chloride product 1; Add 5 - hexen - 1 - ol, pyridine, triethylamine and dimethyl sulfoxide into a flask to obtain mixture 3, and then add the above - mentioned acyl chloride product 1 into dimethyl sulfoxide to obtain mixture 4. Under an ice - water bath at 0 °C, slowly dropwise add mixture 4 into mixture 3. After the addition is complete, heat up to 40 °C and react at a constant temperature for 8 - 10 h, then perform vacuum distillation to prepare the antioxidant;

[0032] Furthermore, the dosage ratio of the supported product, DMF and thionyl chloride is 22 - 24 g: 100 mL: 0.6 - 0.8 mol; the dosage ratio of 5 - hexen - 1 - ol, pyridine, triethylamine and dimethyl sulfoxide is 15 - 20 g: 0.01 - 0.015 mol: 0.1 mol: 85 - 95 mL; the dosage ratio of acyl chloride product 1 and dimethyl sulfoxide is 23 - 25 g: 120 - 130 mL; the dosage ratio of mixture 3 and mixture 4 is 90 - 100 mL: 125 - 135 mL;

[0033] During the reaction process of step B4, the carboxyl group on the surface of the supported product reacts with thionyl chloride to generate acyl chloride product 1; acyl chloride product 1 then reacts with the hydroxyl group of 5 - hexen - 1 - ol to generate an antioxidant containing a terminal double bond.

[0034] The beneficial effects of the present invention: The present invention discloses an anti - aging overhead cable, which includes a conductor core, an insulating layer and a sheath layer from inside to outside; the insulating layer is made of cross - linked polyethylene, and the cross - linked polyethylene is made from raw materials such as low - density polyethylene, a cross - linking agent, a tree - aging resistant agent and an antioxidant.

[0035] The synthesized tree - aging resistant agent includes nano - magnesium oxide, benzophenone structure and terminal carbon - carbon double bonds; the terminal carbon - carbon double bonds enable the tree - aging resistant agent to have cross - linkable sites, increasing the compatibility and dispersibility of the tree - aging resistant agent in the matrix; after the nano - magnesium oxide is modified, its surface hydrophilic - lipophobic property is improved, and it is not easy to agglomerate in the matrix, which not only improves the mechanical properties of the insulating layer material, but also can slow down the aggregation of charges, slow down the accumulation of space charges, improve the breakdown field strength, making the cross - linked polyethylene have good insulation performance and good water - tree resistance; after aromatic stabilizers such as benzophenone are grafted with nano - particles such as nano - magnesium oxide and cross - linked with the matrix through terminal carbon - carbon double bonds, they are not easy to migrate out. Benzophenone can absorb the energy of high - energy electrons and release it in the form of heat energy, reducing the impact of high - energy electrons on the polyethylene chain, improving the voltage - withstanding ability of the insulating material, increasing the tree - inception voltage, and inhibiting the initiation and growth of electrical trees; therefore, using the tree - aging resistant agent can improve the mechanical properties, insulation properties and tree - aging resistance of the cable.

[0036] The synthesized antioxidant is obtained by loading compound s on mesoporous silica, and includes terminal carbon-carbon double bonds, mesoporous silica, hindered phenol structure, thiophene ring and sulfide group; the terminal carbon-carbon double bonds enable the antioxidant to have cross-linkable sites, increasing the compatibility and dispersibility of the antioxidant in the matrix; after compound s is loaded on mesoporous silica, compound s is slowly released during the gradual aging of the matrix, which can effectively inhibit its migration, enabling compound s to reach a high concentration without frosting, and effectively improving the continuous antioxidant capacity of the insulating layer material; the hindered phenol structure generates hydroperoxides in the oxidation degradation reaction of the polymer, terminating the oxidation degradation reaction, while the sulfide group can reduce and decompose hydroperoxides, and the hindered phenol structure and the sulfide group produce a rapid intramolecular synergistic effect to prevent the polymer oxidation reaction from continuing; the thiophene ring can effectively absorb the energy of ultraviolet rays and convert it into thermal energy with lower energy, thereby reducing the damage of ultraviolet rays to the material; therefore, adding the antioxidant makes the cable insulating layer have durable antioxidant aging resistance. Detailed implementation mode

[0037] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0038] Example 1: A tree aging resistant agent, the preparation of which includes the following steps:

[0039] Step A1: Add nano magnesium oxide into toluene, ultrasonically disperse for 40 min, add erucic acid and N,N'-dicyclohexylcarbodiimide under stirring, heat up to 110 °C and stir at a constant temperature for 48 h, then centrifuge for 10 min, centrifuge the lower layer precipitate with absolute ethanol, and finally vacuum dry the lower layer precipitate at 80 °C for 12 h to obtain modified magnesium oxide; the dosage ratio of nano magnesium oxide, toluene, erucic acid and N,N'-dicyclohexylcarbodiimide is 5 g:120 mL:10 g:2 g;

[0040] Step A2: Add the modified magnesium oxide into dichloromethane, start stirring, and then add 3-chloroperoxybenzoic acid, stir and react at room temperature for 4 h to obtain an epoxy product; in a nitrogen atmosphere, add 3-benzoylbenzoic acid and toluene into a flask, heat up to 45 °C, add pyridine, start stirring, add the epoxy product into the flask, stir and react for 8 h, then heat up to 110 °C and stir for 1 h to obtain a hydroxyl product; the dosage ratio of modified magnesium oxide, dichloromethane and 3-chloroperoxybenzoic acid is 12 g:180 mL:0.5 mol; the dosage ratio of 3-benzoylbenzoic acid, toluene, pyridine and the epoxy product is 25 g:100 mL:0.2 mol:13 g;

[0041] Step A3: Add the hydroxy product, pyridine, triethylamine, and dimethyl sulfoxide into a flask to obtain mixture a. Then add acryloyl chloride into dimethyl sulfoxide to obtain mixture b. Under an ice-water bath at 0 °C, slowly add mixture b dropwise to mixture a. After the addition is complete, raise the temperature to 40 °C and carry out a constant-temperature reaction for 8 h. Then perform vacuum distillation to obtain the tree aging-resistant agent. The dosage ratio of the hydroxy product, pyridine, triethylamine, and dimethyl sulfoxide is 14 g: 0.01 mol: 0.5 mol: 70 mL; the dosage ratio of acryloyl chloride and dimethyl sulfoxide is 4.5 g: 20 mL; the dosage ratio of mixture a and mixture b is 75 mL: 25 mL.

[0042] Example 2: A tree aging-resistant agent, the preparation of which comprises the following steps:

[0043] Step A1: Add nano-magnesium oxide into toluene, ultrasonically disperse for 40 min, add erucic acid and N,N'-dicyclohexylcarbodiimide under stirring, raise the temperature to 115 °C and carry out a constant-temperature reflux stirring for 49 h, then centrifuge for 13 min, centrifuge the lower layer precipitate with absolute ethanol, and finally vacuum-dry the lower layer precipitate at 80 °C for 12 h to obtain the modified magnesium oxide. The dosage ratio of nano-magnesium oxide, toluene, erucic acid, and N,N'-dicyclohexylcarbodiimide is 6 g: 120 mL: 10 g: 2 g;

[0044] Step A2: Add the modified magnesium oxide into dichloromethane, start stirring, and then add 3-chloroperoxybenzoic acid, and stir and react at room temperature for 4.5 h to obtain the epoxy product. In a nitrogen atmosphere, add 3-benzoylbenzoic acid and toluene into a flask, raise the temperature to 45 °C, add pyridine, start stirring, add the epoxy product into the flask, stir and react for 9 h, then raise the temperature to 115 °C and stir for 1.5 h to obtain the hydroxy product. The dosage ratio of the modified magnesium oxide, dichloromethane, and 3-chloroperoxybenzoic acid is 14 g: 185 mL: 0.8 mol; the dosage ratio of 3-benzoylbenzoic acid, toluene, pyridine, and the epoxy product is 28 g: 105 mL: 0.23 mol: 14 g;

[0045] Step A3: Add the hydroxy product, pyridine, triethylamine, and dimethyl sulfoxide into a flask to obtain mixture a. Then add acryloyl chloride into dimethyl sulfoxide to obtain mixture b. Under an ice-water bath at 0 °C, slowly add mixture b dropwise to mixture a. After the addition is complete, raise the temperature to 40 °C and carry out a constant-temperature reaction for 9 h. Then perform vacuum distillation to obtain the tree aging-resistant agent. The dosage ratio of the hydroxy product, pyridine, triethylamine, and dimethyl sulfoxide is 15 g: 0.013 mol: 0.8 mol: 75 mL; the dosage ratio of acryloyl chloride and dimethyl sulfoxide is 4.9 g: 25 mL; the dosage ratio of mixture a and mixture b is 80 mL: 30 mL.

[0046] Example 3: A tree aging-resistant agent, the preparation of which comprises the following steps:

[0047] Step A1: Add nano-magnesium oxide into toluene, ultrasonically disperse for 40 min, add erucic acid and N,N'-dicyclohexylcarbodiimide under stirring, heat up to 120 °C, keep stirring under constant temperature reflux for 51 h, then centrifuge for 15 min, centrifuge the lower precipitate with absolute ethanol, and finally vacuum dry the lower precipitate at 80 °C for 12 h to obtain modified magnesium oxide; the dosage ratio of nano-magnesium oxide, toluene, erucic acid and N,N'-dicyclohexylcarbodiimide is 7 g: 120 mL: 10 g: 2 g;

[0048] Step A2: Add the modified magnesium oxide into dichloromethane, start stirring, then add 3-chloroperoxybenzoic acid, and stir and react at room temperature for 5 h to obtain an epoxy product; in a nitrogen atmosphere, add 3-benzoylbenzoic acid and toluene into a flask, heat up to 45 °C, add pyridine, start stirring, add the epoxy product into the flask, stir and react for 10 h, then heat up to 120 °C and stir for 2 h to obtain a hydroxyl product; the dosage ratio of modified magnesium oxide, dichloromethane and 3-chloroperoxybenzoic acid is 16 g: 190 mL: 1.0 mol; the dosage ratio of 3-benzoylbenzoic acid, toluene, pyridine and the epoxy product is 30 g: 110 mL: 0.25 mol: 15 g;

[0049] Step A3: Add the hydroxyl product, pyridine, triethylamine and dimethyl sulfoxide into a flask to obtain mixture a, and add acryloyl chloride into dimethyl sulfoxide to obtain mixture b. Under an ice bath at 0 °C, slowly drip mixture b into mixture a. After dripping, heat up to 40 °C and keep reacting at a constant temperature for 10 h, then carry out vacuum distillation to prepare a dendrite aging-resistant agent; the dosage ratio of the hydroxyl product, pyridine, triethylamine and dimethyl sulfoxide is 16 g: 0.015 mol: 1.0 mol: 80 mL; the dosage ratio of acryloyl chloride and dimethyl sulfoxide is 5.4 g: 30 mL; the dosage ratio of mixture a and mixture b is 85 mL: 35 mL.

[0050] Example 4: An antioxidant, the preparation of which comprises the following steps:

[0051] Step B1: In a nitrogen atmosphere, add 5-methylthiophene-2-carbaldehyde and acetic anhydride into a reaction flask, start reflux stirring, heat up to 150 °C, then add potassium carbonate, and keep stirring under constant temperature reflux for 24 h, extract, rotary evaporate and dry to obtain an unsaturated carboxylic acid; add the unsaturated carboxylic acid into DMF, start stirring, slowly add thionyl chloride, heat up to 40 °C, and keep stirring and reacting for 4 h, filter, extract and dry to obtain an acyl chloride product; the dosage ratio of 5-methylthiophene-2-carbaldehyde, acetic anhydride and potassium carbonate is 0.1 mol: 0.05 mol: 5 mmol; the dosage ratio of the unsaturated carboxylic acid, DMF and thionyl chloride is 0.1 mol: 90 mL: 0.1 mol;

[0052] Step B2: Add 3,5-di-tert-butyl-4-hydroxybenzyl alcohol, pyridine, triethylamine, and dimethyl sulfoxide into a flask to obtain mixture 1. Then add the above acyl chloride product into dimethyl sulfoxide to obtain mixture 2. Under an ice-water bath at 0 °C, slowly add mixture 2 dropwise to mixture 1. After the addition is complete, raise the temperature to 40 °C and carry out a constant-temperature reaction for 8 h. Then perform vacuum distillation to obtain compound s. The dosage ratio of 3,5-di-tert-butyl-4-hydroxybenzyl alcohol, pyridine, triethylamine, and dimethyl sulfoxide is 0.1 mol: 0.01 mol: 0.1 mol: 80 mL; the dosage ratio of the acyl chloride product and dimethyl sulfoxide is 0.1 mol: 100 mL; the dosage ratio of mixture 1 and mixture 2 is 85 mL: 105 mL;

[0053] Step B3: Add compound S into acetone. After stirring at room temperature for 15 min, a mixture is obtained. Then add carboxyl-functionalized hollow mesoporous silica and stir at room temperature for 2 h. Then evacuate for 30 min and then let in air for 15 min. Repeat the steps of evacuation and then letting in air three times. After washing with ethanol and deionized water, drying, and grinding, the supported product is obtained. The dosage ratio of compound S, acetone, and carboxyl-functionalized hollow mesoporous silica is 43 g: 430 mL: 20 g;

[0054] Step B4: Add the supported product into DMF, start stirring, and slowly add thionyl chloride. Raise the temperature to 40 °C and carry out a constant-temperature stirring reaction for 4 h. After filtration, extraction, and drying, acyl chloride product 1 is obtained. Add 5-hexen-1-ol, pyridine, triethylamine, and dimethyl sulfoxide into a flask to obtain mixture 3. Then add the above acyl chloride product 1 into dimethyl sulfoxide to obtain mixture 4. Under an ice-water bath at 0 °C, slowly add mixture 4 dropwise to mixture 3. After the addition is complete, raise the temperature to 40 °C and carry out a constant-temperature reaction for 8 h. Then perform vacuum distillation to obtain the antioxidant. The dosage ratio of the supported product, DMF, and thionyl chloride is 22 g: 100 mL: 0.6 mol; the dosage ratio of 5-hexen-1-ol, pyridine, triethylamine, and dimethyl sulfoxide is 15 g: 0.01 mol: 0.1 mol: 85 mL; the dosage ratio of acyl chloride product 1 and dimethyl sulfoxide is 23 g: 120 mL; the dosage ratio of mixture 3 and mixture 4 is 90 mL: 125 mL.

[0055] Example 5: An antioxidant, the preparation of which comprises the following steps:

[0056] Step B1: In a nitrogen atmosphere, add 5-methylthiophene-2-carbaldehyde and acetic anhydride into a reaction flask, start reflux stirring, heat up to 160 °C, then add potassium carbonate, keep the temperature constant and reflux and stir for 25 h, extract, rotary evaporate, and dry to obtain an unsaturated carboxylic acid; add the unsaturated carboxylic acid into DMF, start stirring, slowly add thionyl chloride, heat up to 45 °C, keep the temperature constant and stir for 4.5 h, filter, extract, and dry to obtain an acyl chloride product; the dosage ratio of 5-methylthiophene-2-carbaldehyde, acetic anhydride, and potassium carbonate is 0.1 mol: 0.06 mol: 6 mmol; the dosage ratio of the unsaturated carboxylic acid, DMF, and thionyl chloride is 0.1 mol: 90 mL: 0.13 mol;

[0057] Step B2: Add 3,5-di-tert-butyl-4-hydroxybenzyl alcohol, pyridine, triethylamine, and dimethyl sulfoxide into a flask to obtain mixture 1, and then add the above acyl chloride product into dimethyl sulfoxide to obtain mixture 2. Under an ice-water bath at 0 °C, slowly dropwise add mixture 2 into mixture 1. After the addition is completed, heat up to 40 °C and keep the temperature constant for reaction for 9 h, and carry out vacuum distillation to obtain compound s; the dosage ratio of 3,5-di-tert-butyl-4-hydroxybenzyl alcohol, pyridine, triethylamine, and dimethyl sulfoxide is 0.1 mol: 0.013 mol: 0.1 mol: 85 mL; the dosage ratio of the acyl chloride product and dimethyl sulfoxide is 0.1 mol: 105 mL; the dosage ratio of mixture 1 and mixture 2 is 90 mL: 110 mL;

[0058] Step B3: Add compound S into acetone, stir for 15 min at room temperature to obtain a mixture, then add carboxyl-functionalized hollow mesoporous silica, stir at room temperature for 2.3 h, evacuate for 30 min, then let in the atmosphere for 15 min, repeat the steps of evacuation and letting in the atmosphere three times, wash with ethanol and deionized water, dry, and grind to obtain a supported product; the dosage ratio of compound S, acetone, and carboxyl-functionalized hollow mesoporous silica is 44 g: 440 mL: 23 g;

[0059] Step B4: Add the loaded product into DMF, start stirring, slowly add thionyl chloride, heat up to 45 °C, keep stirring and reacting at a constant temperature for 4.5 h, filter, extract, and dry to obtain acyl chloride product 1; Add 5-hexen-1-ol, pyridine, triethylamine, and dimethyl sulfoxide into a flask to obtain mixture 3, then add the above acyl chloride product 1 into dimethyl sulfoxide to obtain mixture 4. Under an ice-water bath at 0 °C, slowly dropwise add mixture 4 into mixture 3. After the addition is complete, heat up to 40 °C and react at a constant temperature for 9 h, then perform vacuum distillation to prepare the antioxidant; The dosage ratio of the loaded product, DMF, and thionyl chloride is 23 g: 100 mL: 0.7 mol; The dosage ratio of 5-hexen-1-ol, pyridine, triethylamine, and dimethyl sulfoxide is 18 g: 0.013 mol: 0.1 mol: 90 mL; The dosage ratio of acyl chloride product 1 and dimethyl sulfoxide is 24 g: 125 mL; The dosage ratio of mixture 3 and mixture 4 is 95 mL: 130 mL.

[0060] Example 6: An antioxidant, the preparation thereof comprises the following steps:

[0061] Step B1: Under a nitrogen atmosphere, add 5-methylthiophene-2-carbaldehyde and acetic anhydride into a reaction flask, start reflux stirring, heat up to 170 °C, then add potassium carbonate, keep reflux stirring and reacting at a constant temperature for 26 h, extract, rotary evaporate, and dry to obtain an unsaturated carboxylic acid; Add the unsaturated carboxylic acid into DMF, start stirring, slowly add thionyl chloride, heat up to 50 °C, keep stirring and reacting at a constant temperature for 5 h, filter, extract, and dry to obtain the acyl chloride product; The dosage ratio of 5-methylthiophene-2-carbaldehyde, acetic anhydride, and potassium carbonate is 0.1 mol: 0.07 mol: 8 mmol; The dosage ratio of the unsaturated carboxylic acid, DMF, and thionyl chloride is 0.1 mol: 90 mL: 0.15 mol;

[0062] Step B2: Add 3,5-di-tert-butyl-4-hydroxybenzyl alcohol, pyridine, triethylamine, and dimethyl sulfoxide into a flask to obtain mixture 1, then add the above acyl chloride product into dimethyl sulfoxide to obtain mixture 2. Under an ice-water bath at 0 °C, slowly dropwise add mixture 2 into mixture 1. After the addition is complete, heat up to 40 °C and react at a constant temperature for 10 h, then perform vacuum distillation to obtain compound s; The dosage ratio of 3,5-di-tert-butyl-4-hydroxybenzyl alcohol, pyridine, triethylamine, and dimethyl sulfoxide is 0.1 mol: 0.015 mol: 0.1 mol: 90 mL; The dosage ratio of the acyl chloride product and dimethyl sulfoxide is 0.1 mol: 110 mL; The dosage ratio of mixture 1 and mixture 2 is 95 mL: 115 mL;

[0063] Step B3: Add compound S into acetone, stir for 20 min at room temperature to obtain a mixture, then add carboxyl-functionalized hollow mesoporous silica, stir for 2.5 h at room temperature, evacuate for 30 min, then let in air for 15 min, repeat the evacuation and letting-in-air steps three times, wash with ethanol and deionized water, dry and grind to obtain the supported product; the dosage ratio of compound S, acetone and carboxyl-functionalized hollow mesoporous silica is 45 g: 450 mL: 25 g;

[0064] Step B4: Add the supported product into DMF, start stirring, slowly add thionyl chloride, heat up to 50 °C, stir and react at a constant temperature for 5 h, filter, extract and dry to obtain acyl chloride product 1; add 5-hexen-1-ol, pyridine, triethylamine and dimethyl sulfoxide into a flask to obtain mixture 3, then add the above acyl chloride product 1 into dimethyl sulfoxide to obtain mixture 4, under an ice bath at 0 °C, slowly dropwise add mixture 4 into mixture 3, after the addition is complete, heat up to 40 °C, react at a constant temperature for 10 h, and carry out vacuum distillation to prepare the antioxidant; the dosage ratio of the supported product, DMF and thionyl chloride is 24 g: 100 mL: 0.8 mol; the dosage ratio of 5-hexen-1-ol, pyridine, triethylamine and dimethyl sulfoxide is 20 g: 0.015 mol: 0.1 mol: 95 mL; the dosage ratio of acyl chloride product 1 and dimethyl sulfoxide is 25 g: 130 mL; the dosage ratio of mixture 3 and mixture 4 is 100 mL: 135 mL.

[0065] Example 7: An anti-aging overhead cable, which includes a conductor core, an insulating layer and a sheath layer from the inside to the outside; the conductor core is composed of 14 aluminum alloy wires stranded together, and the sheath layer is made of TPE sheath material; the insulating layer is made of cross-linked polyethylene, and the cross-linked polyethylene includes the following raw materials in parts by weight: 170 parts of low-density polyethylene, 10 parts of cross-linking agent, 8.5 parts of anti-treeing aging agent and 4 parts of antioxidant; the cross-linking agent is benzoyl peroxide;

[0066] The preparation of the anti-aging overhead cable includes the following steps:

[0067] Step S1: Put the low-density polyethylene into a rheometer for melt blending, mix at 105 °C and a rotation speed of 50 r / min for 4 min, then add the anti-treeing aging agent and cross-linking agent obtained in Example 1, mix for another 3 min, add the antioxidant obtained in Example 4, and finally mix for 10 min to obtain cross-linked polyethylene;

[0068] Step S2: Stranded the aluminum alloy wires to form a conductor core, extrude and deposit the cross-linked polyethylene on the outer periphery of the conductor core with an extruder to form an insulating layer; then extrude and deposit the TPE sheath material on the outer periphery of the insulating layer to obtain a sheath layer, and carry out annealing treatment after extrusion to obtain the anti-aging overhead cable.

[0069] Example 8: An anti-aging aerial cable, which includes a conductor core, an insulating layer, and a sheath layer from the inside out; the conductor core is composed of 16 aluminum alloy wires stranded together, the sheath layer is made of TPE sheath material; the insulating layer is made of cross-linked polyethylene, and the cross-linked polyethylene includes the following raw materials in parts by weight: 175 parts of low-density polyethylene, 11 parts of cross-linking agent, 9.5 parts of treeing aging resistant agent, and 5 parts of antioxidant; the cross-linking agent is benzoyl peroxide;

[0070] The preparation of the anti-aging aerial cable includes the following steps:

[0071] Step S1: Put the low-density polyethylene into a rheometer for melt blending, mix it at 105 °C and a rotation speed of 50 r / min for 5 min, then add the treeing aging resistant agent and cross-linking agent obtained in Example 2, mix it for another 3 min, add the antioxidant obtained in Example 5, and finally mix it for 13 min to obtain cross-linked polyethylene;

[0072] Step S2: Stranded the aluminum alloy wires to form a conductor core, extrude and deposit the cross-linked polyethylene on the outer periphery of the conductor core with an extruder to form an insulating layer; then extrude and deposit the TPE sheath material on the outer periphery of the insulating layer to obtain a sheath layer, and perform annealing treatment after extrusion to obtain the anti-aging aerial cable.

[0073] Example 9: An anti-aging aerial cable, which includes a conductor core, an insulating layer, and a sheath layer from the inside out; the conductor core is composed of 18 aluminum alloy wires stranded together, the sheath layer is made of TPE sheath material; the insulating layer is made of cross-linked polyethylene, and the cross-linked polyethylene includes the following raw materials in parts by weight: 180 parts of low-density polyethylene, 12 parts of cross-linking agent, 10.5 parts of treeing aging resistant agent, and 6 parts of antioxidant; the cross-linking agent is benzoyl peroxide;

[0074] The preparation of the anti-aging aerial cable includes the following steps:

[0075] Step S1: Put the low-density polyethylene into a rheometer for melt blending, mix it at 110 °C and a rotation speed of 50 r / min for 6 min, then add the treeing aging resistant agent and cross-linking agent obtained in Example 3, mix it for another 3 min, add the antioxidant obtained in Example 6, and finally mix it for 15 min to obtain cross-linked polyethylene;

[0076] Step S2: Stranded the aluminum alloy wires to form a conductor core, extrude and deposit the cross-linked polyethylene on the outer periphery of the conductor core with an extruder to form an insulating layer; then extrude and deposit the TPE sheath material on the outer periphery of the insulating layer to obtain a sheath layer, and perform annealing treatment after extrusion to obtain the anti-aging aerial cable.

[0077] Comparative Example 1: This comparative example is a commercially available anti-aging aerial cable, and its insulating layer is made of ordinary cross-linked polyethylene material.

[0078] Comparative Example 2: Compared with Example 9, the anti-tree aging agent was replaced with anti-tree aging agent d, and the remaining steps were exactly the same as those in Example 9 to obtain an aging-resistant aerial cable; the preparation process of anti-tree aging agent d was as follows: in step A2 of Example 3, 3-benzoylbenzoic acid was replaced with acrylic acid, that is, the benzophenone structure was not introduced, and then anti-tree aging agent d was obtained according to the reaction steps of Example 3.

[0079] Comparative Example 3: Compared with Example 9, the antioxidant was replaced with compound s obtained in Example 6, that is, mesoporous silica was not used, and the remaining steps were exactly the same as those in Example 9 to obtain an aging-resistant aerial cable.

[0080] The following is a further effect test on the aging-resistant aerial cable prepared by the present invention, and the test results are as follows.

[0081] To test the aging-resistant aerial cable prepared by the present invention, the mechanical properties (tensile strength and elongation at break) of the insulation layer were tested according to GB / T 2951-2008 "General Test Methods for Insulating and Sheathing Materials of Cables and Optical Fibre Cables", and the results were recorded in Table 1.

[0082] The test methods for the average AC breakdown field strength and the average DC breakdown field strength in Table 1 were as follows: at room temperature, a linearly increasing AC high voltage or DC high voltage was applied to a 100-μm-thick film sample of the insulation layer material of the cables in Examples 7-9 and Comparative Examples 1-3 until the sample broke down. According to the method of GB / T 11017.1-2014 "Rated Voltage 110 kV Crosslinked Polyethylene Insulated Power Cables and Accessories", the average AC breakdown field strength and the average DC breakdown field strength of 10 samples were obtained respectively, and the results were recorded in Table 1.

[0083] The test method for the average electrical tree initiation voltage in Table 1 was as follows: the electrical tree initiation voltage test at room temperature was carried out on the insulation layer materials of the cables in Examples 7-9 and Comparative Examples 1-3 by using a needle-plate electrode structure. The distance between the needle and the plate was 3 mm, the tip curvature radius was 5 μm, and the voltage increase mode was linear voltage increase. According to the method of GB / T 11017.1-2014 "Rated Voltage 110 kV Crosslinked Polyethylene Insulated Power Cables and Accessories", the average electrical tree initiation voltage of 10 samples was obtained, and the results were recorded in Table 1.

[0084] The aging method in Table 1 was as follows: the insulation layer materials of the cables in Examples 7-9 and Comparative Examples 1-3 were placed under the conditions of an ultraviolet light intensity of 0.89 W / m 2 , a temperature of 50 °C, and an aging time of 30 d for aging, and then the tensile strength retention rate and elongation at break retention rate were measured according to the method of GB / T 2951-2008, and the results were recorded in Table 1.

[0085] Table 1: Test Results

[0086]

[0087] According to the data in Table 1, comparing Examples 7-9 with Comparative Example 1 shows that the insulating layer of the anti-aging overhead cable prepared by the present invention has good mechanical properties, resistance to tree aging, insulation properties, and antioxidant aging properties, thus making the mechanical properties and anti-aging properties of the cable excellent and extending its service life. Comparing Example 9 with Comparative Example 2 shows that by using an anti-tree-aging agent and introducing a benzophenone structure, the breakdown voltage performance of the insulating layer of the overhead cable is improved, the growth of electrical trees is effectively inhibited, which is beneficial to the improvement of the anti-tree-aging performance of the cable. Comparing Example 9 with Comparative Example 3 shows that by using an antioxidant and loading compound s with mesoporous silica, compound s is not easily migrated and can be slowly released, which is more helpful for improving the continuous antioxidant aging performance of the insulating layer, thus contributing to the improvement of the antioxidant aging performance of the cable.

[0088] The above content is only an example and illustration of the concept of the present invention. Those skilled in the art of the present technology can make various modifications or supplements to the described specific embodiments or use similar methods for substitution, as long as they do not deviate from the concept of the invention or exceed the scope defined by the claims of the present invention, they should all fall within the protection scope of the present invention.

Claims

1. An aging-resistant overhead cable, characterized in that: From the inside to the outside, it includes a conductor core, an insulating layer and a sheath layer; the insulating layer is made of cross-linked polyethylene, and the cross-linked polyethylene includes the following raw materials by weight: 170-180 parts of low-density polyethylene, 10-12 parts of a cross-linking agent, 8.5-10.5 parts of a tree aging resistance agent, and 4-6 parts of an antioxidant; The preparation of the anti-branching agent comprises the following steps: Step A1: Add nano magnesium oxide to toluene, ultrasonically disperse for 40 minutes, add erucic acid and N, N'-dicyclohexyl diimide under stirring, heat to 110-120°C, reflux and stir for 48-51 hours, then centrifuge for 10-15 minutes, centrifuge the lower precipitate with anhydrous ethanol, and finally vacuum dry the lower precipitate at 80°C for 12 hours to obtain modified magnesium oxide; Step A2: Add modified magnesium oxide to dichloromethane, start stirring, then add 3-chloroperoxybenzoic acid, stir and react at room temperature for 4-5 hours to obtain an epoxy product; in a nitrogen atmosphere, add 3-benzoylbenzoic acid and toluene to a flask, heat to 45°C, add pyridine, start stirring, add the epoxy product to the flask, stir and react for 8-10 hours, then heat to 110-120°C, stir for 1-2 hours to obtain a hydroxyl product; Step A3: Add the hydroxyl product, pyridine, triethylamine and dimethyl sulfoxide into a flask to obtain a mixed solution a, then add acryloyl chloride into dimethyl sulfoxide to obtain a mixed solution b, slowly drop the mixed solution b into the mixed solution a in an ice water bath at 0°C, after the dropwise addition is completed, heat to 40°C, react at a constant temperature for 8-10 hours, and distill under reduced pressure to obtain a tree aging resistant agent.

2. The aging-resistant overhead cable according to claim 1, characterized in that: In step A1, the usage ratio of nano-magnesium oxide, toluene, erucic acid and N,N'-dicyclohexyldiimide is 5-7 g:120 mL:10 g:2 g.

3. The aging-resistant overhead cable according to claim 1, characterized in that: In step A2, the usage ratio of modified magnesium oxide, dichloromethane and 3-chloroperoxybenzoic acid is 12-16 g: 180-190 mL: 0.5-1.0 mol; the usage ratio of 3-benzoylbenzoic acid, toluene, pyridine and epoxy product is 25-30 g: 100-110 mL: 0.2-0.25 mol: 13-15 g.

4. The aging-resistant overhead cable according to claim 1, characterized in that: In step A3, the usage ratio of the hydroxyl product, pyridine, triethylamine and dimethyl sulfoxide is 14-16 g: 0.01-0.015 mol: 0.5-1.0 mol: 70-80 mL; the usage ratio of acryloyl chloride and dimethyl sulfoxide is 4.5-5.4 g: 20-30 mL; the usage ratio of mixed solution a and mixed solution b is 75-85 mL: 25-35 mL.

5. The aging-resistant overhead cable according to claim 1, characterized in that: The preparation of the antioxidant comprises the following steps: Step B1: In a nitrogen atmosphere, 5-methylthiothiophene-2-carboxaldehyde and acetic anhydride are added to a reaction bottle, refluxed and stirred, and the temperature is raised to 150-170°C, and potassium carbonate is added, and the reaction is stirred at constant temperature for 24-26 hours, and the unsaturated carboxylic acid is extracted, rotary evaporated, and dried to obtain an unsaturated carboxylic acid; the unsaturated carboxylic acid is added to DMF, stirred, and thionyl chloride is slowly added, the temperature is raised to 40-50°C, and the reaction is stirred at constant temperature for 4-5 hours, and the acyl chloride product is obtained by filtering, extracting, and drying; Step B2: Add 3,5-di-tert-butyl-4-hydroxybenzyl alcohol, pyridine, triethylamine and dimethyl sulfoxide into a flask to obtain a mixed solution 1, then add the above-mentioned acyl chloride product into dimethyl sulfoxide to obtain a mixed solution 2, slowly dropwise add the mixed solution 2 into the mixed solution 1 in an ice-water bath at 0°C, after the dropwise addition is completed, heat to 40°C, react at a constant temperature for 8-10 hours, and distill under reduced pressure to obtain compound s; Step B3: Compound s is added to acetone, and the mixture is stirred at room temperature for 10-20 minutes to obtain a mixed solution, and then carboxyl hollow mesoporous silica is added, and the mixture is stirred at room temperature for 2-2.5 hours, and then vacuumed for 30 minutes, and then allowed to flow to the atmosphere for 15 minutes. The steps of vacuuming and then allowing to flow to the atmosphere are repeated three times, and the loaded product is obtained after washing with ethanol and deionized water, drying and grinding; Step B4: Add the loaded product to DMF, start stirring, slowly add dichlorothionyl, raise the temperature to 40-50°C, stir and react at constant temperature for 4-5h, filter, extract and dry to obtain the acyl chloride product 1; add 5-hexen-1-ol, pyridine, triethylamine and dimethyl sulfoxide to a flask to obtain a mixed solution 3, then add the above-mentioned acyl chloride product 1 to dimethyl sulfoxide to obtain a mixed solution 4, slowly drop the mixed solution 4 into the mixed solution 3 in an ice-water bath at 0°C, after the dropwise addition is completed, raise the temperature to 40°C, react at constant temperature for 8-10h, and distill under reduced pressure to obtain an antioxidant.

6. The aging-resistant overhead cable according to claim 5, characterized in that: In step B1, the usage ratio of 5-methylthiothiophene-2-carboxaldehyde, acetic anhydride and potassium carbonate is 0.1 mol: 0.05-0.07 mol: 5-8 mmol; the usage ratio of unsaturated carboxylic acid, DMF and dichlorothionyl is 0.1 mol: 90 mL: 0.1-0.15 mol; in step B3, the usage ratio of compound S, acetone and carboxyl hollow mesoporous silica is 43-45 g: 430-450 mL: 20-25 g.

7. The aging-resistant overhead cable according to claim 5, characterized in that: In step B2, the usage ratio of 3,5-di-tert-butyl-4-hydroxybenzyl alcohol, pyridine, triethylamine and dimethyl sulfoxide is 0.1 mol: 0.01-0.015 mol: 0.1 mol: 80-90 mL; the usage ratio of the acyl chloride product and dimethyl sulfoxide is 0.1 mol: 100-110 mL; the usage ratio of mixed solution 1 and mixed solution 2 is 85-95 mL: 105-115 mL.

8. The aging-resistant overhead cable according to claim 5, characterized in that: In step B4, the amount ratio of the loaded product, DMF, and dichlorothionyl is 22-24 g: 100 mL: 0.6-0.8 mol; the amount ratio of 5-hexen-1-ol, pyridine, triethylamine and dimethyl sulfoxide is 15-20 g: 0.01-0.015 mol: 0.1 mol: 85-95 mL; the amount ratio of the acyl chloride product 1 and dimethyl sulfoxide is 23-25 ​​g: 120-130 mL; the amount ratio of the mixed solution 3 and the mixed solution 4 is 90-100 mL: 125-135 mL.

9. The aging-resistant overhead cable according to claim 1, characterized in that: The conductor core is formed by twisting a plurality of aluminum alloy wires, the sheath layer is made of TPE sheath material, and the cross-linking agent is benzoyl peroxide.

10. The production process of an aging-resistant overhead cable according to claim 1, characterized in that: The steps include: Step S1: low-density polyethylene is placed in a rheometer for melt blending, mixed at 105-110° C. and a rotation speed of 50 r / min for 4-6 minutes, then an anti-tree aging agent and a cross-linking agent are added, mixed for another 3 minutes, an antioxidant is added, and finally mixed for 10-15 minutes to obtain cross-linked polyethylene; Step S2: Twisting the aluminum alloy wires to form a conductor core, extruding and depositing the cross-linked polyethylene on the periphery of the conductor core using an extruder to form an insulating layer; then extruding and depositing the TPE sheath material on the periphery of the insulating layer to obtain a sheath layer, and annealing after extrusion to obtain an aging-resistant overhead cable.

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