Wear-resistant medium-voltage power cable

Abstract

The invention relates to the technical field of cables, and provides a wear-resistant medium-voltage power cable, which comprises a conductor, an insulating layer and a sheath layer which are sequentially arranged from inside to outside, the sheath layer comprises the following raw materials: an ethylene-vinyl acetate copolymer, high-density polyethylene, polyethylene grafted maleic anhydride, a modified monomer, a wear-resistant filler, an antioxidant, a lubricant and a sensitizer. The preparation method has the beneficial effects that the modified monomer containing a flame-retardant structure and a triazole ring group is chemically synthesized, so that the mechanical property and the flame-retardant effect of the cable sheath material are effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of cables, and in particular to a wear-resistant medium-voltage power cable. Background Art

[0002] In the field of cable technology, medium voltage power cables are widely used in power transmission and distribution systems, and their performance directly affects the safety and reliability of the power grid.

[0003] Traditional cable sheath materials usually use polymers such as polyethylene (PE), polyvinyl chloride (PVC) or rubber. Although they have certain mechanical strength and insulation properties, they still have obvious defects in practical applications. First, ordinary sheath materials have poor wear resistance and are prone to wear in complex environments (such as underground laying, mechanical vibration or frequent friction), resulting in exposure of the cable insulation layer and increasing the risk of short circuit or breakdown. Secondly, the flame retardant properties of existing materials are insufficient, and the oxygen index is low. They are easy to burn and release toxic gases under high temperature or fire conditions, threatening the safety of personnel and equipment. In addition, traditional fillers (such as silica or calcium carbonate) have poor compatibility with the polymer matrix and are easy to agglomerate, resulting in a decrease in mechanical properties and an inability to effectively disperse stress. Although some studies have attempted to improve performance by adding flame retardants or reinforcing fillers, they often sacrifice the flexibility or processing properties of the material.

[0004] Therefore, in order to solve the above problems, the present invention proposes a wear-resistant medium voltage power cable. Summary of the Invention

[0005] The present invention provides a wear-resistant medium-voltage power cable, which solves the defects in the related art.

[0006] The technical solutions of the present invention are as follows: A wear-resistant medium-voltage power cable comprises a conductor, an insulation layer and a sheath layer which are sequentially arranged from the inside to the outside; the sheath layer comprises the following raw materials: by weight, 30-50 parts of ethylene-vinyl acetate copolymer, 20-40 parts of high-density polyethylene, 5-15 parts of polyethylene grafted maleic anhydride, 10-12 parts of modified monomer, 20-30 parts of wear-resistant filler, 1-2 parts of antioxidant, 1-2 parts of lubricant, and 2-3 parts of sensitizer.

[0007] More optimally, the preparation process of the modified monomer is: S1: Mix 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide with dichloromethane, stir until completely dissolved, add triethylamine, continue stirring for 10-20 minutes, then cool to 0°C, add 2-azidoethanol, and continue adding carbon tetrachloride at 0°C. Stir at room temperature overnight and post-treat to obtain intermediate A; S2: Mix acetylene dicarboxylic acid and toluene, stir to dissolve, add allyl alcohol, and finally add p-toluenesulfonic acid, raise the temperature to 110-120°C, reflux for 8-10 hours, cool to room temperature, and post-treat to obtain intermediate B; S3: Intermediate A, intermediate B, and 2-methyltetrahydrofuran are mixed and stirred until completely dissolved. The temperature is then raised to 80-90° C. and refluxed for 24 hours. The reaction solution is added to hexane, precipitated, washed, and dried to obtain a modified monomer.

[0008] In the scheme, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is deprotonated by triethylamine to generate a phosphorus anion, which then attacks the hydroxyl carbon of 2-azidoethanol to obtain intermediate A. The specific synthesis process is shown below:

[0009] More optimally, the intermediate A raw materials include the following substances: by weight, 10-12 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 50-60 parts of dichloromethane, 7-8 parts of triethylamine, 4-5 parts of 2-azidoethanol, and 5-6 parts of carbon tetrachloride.

[0010] In the scheme, the carboxylic acid group of acetylene dicarboxylic acid can undergo esterification reaction with the hydroxyl group of allyl alcohol in the presence of an acidic catalyst to obtain intermediate B. The specific synthesis process is shown below:

[0011] More optimally, the raw materials of intermediate B include the following substances: 6-7 parts of acetylene dicarboxylic acid, 40-50 parts of toluene, 6-7 parts of allyl alcohol, and 0.2-0.3 parts of p-toluenesulfonic acid, by weight.

[0012] In the scheme, the azide group of intermediate A undergoes cycloaddition with the alkyne bond of diallyl acetylene dicarboxylate to obtain a modified monomer; its structure is shown below:

[0013] More optimally, the modified monomer raw material includes the following substances: 10-12 parts of intermediate A, 7-8 parts of intermediate B, and 40-50 parts of 2-methyltetrahydrofuran, by weight.

[0014] More optimally, the wear-resistant filler includes nano-aluminum oxide and nano-zinc oxide in a mass ratio of 2:1.

[0015] More optimally, the antioxidant includes one or both of antioxidant 1010 and antioxidant 168 .

[0016] More optimally, the lubricant includes one or more of zinc stearate, calcium stearate, barium stearate or polyethylene wax.

[0017] More preferably, the sensitizer includes trimethylolpropane trimethacrylate.

[0018] More optimally, the preparation process of the cable is: After the insulation layer is extruded and coated on the surface of the conductor, ethylene-vinyl acetate copolymer, high-density polyethylene, polyethylene grafted maleic anhydride, modified monomer, wear-resistant filler, antioxidant, and lubricant are mixed and kneaded for 5-8 minutes, and then a sensitizer is added and kneaded for 10-15 minutes. After the material is discharged, it is granulated and dried, and then extruded through an extruder and coated on the surface of the insulation layer. After irradiation and cross-linking, a wear-resistant medium-voltage power cable is obtained.

[0019] More preferably, the conductor is a copper alloy conductor.

[0020] The insulating layer is a polyvinyl chloride insulating layer.

[0021] Compared with the prior art, the present invention has the following advantages: The present invention introduces a modified monomer into the cable sheath layer, wherein the modified monomer contains a flame retardant structure and a triazole group. The introduction of the modified monomer effectively improves the mechanical properties and flame retardant effect of the cable sheath material. The details are as follows: First, the modified monomer's 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide structure catalyzes carbonization within the polymer matrix during combustion, forming a dense and stable carbon layer that effectively isolates oxygen and heat, inhibits flame spread, and enhances the material's flame retardancy. Furthermore, the double bonds within the modified monomer participate in cross-linking reactions, and the rigid aromatic and triazole ring structures it contains form a network within the polymer matrix, enhancing the material's tensile strength. Furthermore, the introduction of polyethylene grafted maleic anhydride further promotes interfacial compatibility, resulting in a tighter bond between the matrix and filler, reducing stress concentration and improving overall mechanical properties.

[0022] Second, in this scheme, the triazole ring structure in the modified monomer can form coordination bonds with the metal ions on the surface of the nano-aluminum oxide and nano-zinc oxide in the wear-resistant filler. Specifically, there are a large number of unsaturated coordinated metal ions on the surface of the wear-resistant filler, whose empty orbitals can form coordination bonds with the nitrogen atoms of the triazole ring. This multi-point coordination disperses the filler particles in the polymer matrix, allowing the nano-aluminum oxide and zinc oxide to exist in a monodisperse state, improving the interfacial bonding strength between the filler and the matrix. When the cable sheath is subjected to friction, the dispersed nano-fillers can serve as hard support points to withstand shear forces, reducing direct wear of the polymer matrix. DETAILED DESCRIPTION

[0023] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0024] In the following examples and comparative examples, the ethylene-vinyl acetate copolymer has a model number of EVA V5110J and a CAS number of 24937-78-8; the polyethylene grafted maleic anhydride has a model number of 41E710 and a CAS number of 9006-26-2; the high-density polyethylene has a model number of DMDA-8920; the CAS number of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is 35948-25-5; the CAS number of 2-azidoethanol is 1517-05-1; and the CAS number of acetylene dicarboxylic acid is 142-45-0.

[0025] Example 1: A preparation process for a wear-resistant medium-voltage power cable is as follows: After extruding and coating the surface of the copper alloy conductor with a polyvinyl chloride insulation layer, 30 parts of ethylene-vinyl acetate copolymer, 20 parts of high-density polyethylene, 5 parts of polyethylene grafted maleic anhydride, 10 parts of modified monomer, 20 parts of wear-resistant filler (nano-alumina and nano-zinc oxide with a mass ratio of 2:1), 1 part of antioxidant 1010, and 1 part of lubricant (zinc stearate) were mixed and kneaded for 5 minutes. Then, a sensitizer (trimethylolpropane trimethacrylate) was added and kneaded for 10 minutes. After discharging, the material was granulated and dried, and then extruded and coated on the surface of the polyvinyl chloride insulation layer through an extruder. After irradiation and cross-linking (irradiation dose of 8 Mrad), a wear-resistant medium voltage power cable was obtained. Wherein, the preparation process of the modified monomer is: S1: 10 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide were mixed with 50 parts of dichloromethane, stirred until completely dissolved, 7 parts of triethylamine were added, and stirring was continued for 10 minutes. After that, the mixture was cooled to 0°C, 4 parts of 2-azidoethanol were added, and 5 parts of carbon tetrachloride were added at 0°C. The mixture was stirred at room temperature overnight and post-treated to obtain intermediate A. S2: Mix 6 parts of acetylene dicarboxylic acid with 40 parts of toluene, stir and dissolve, add 6 parts of allyl alcohol, and finally add 0.2 parts of p-toluenesulfonic acid, raise the temperature to 110°C, reflux for 8 hours, cool to room temperature, and post-treat to obtain intermediate B; S3: 10 parts of intermediate A, 7 parts of intermediate B, and 40 parts of 2-methyltetrahydrofuran were mixed and stirred until completely dissolved. The temperature was then raised to 80°C and refluxed for 24 hours. The reaction solution was added to hexane, precipitated, washed, and dried to obtain a modified monomer.

[0026] Example 2: A preparation process for a wear-resistant medium-voltage power cable is as follows: After extruding and coating the polyvinyl chloride insulation layer on the surface of the copper alloy conductor, 50 parts of ethylene-vinyl acetate copolymer, 40 parts of high-density polyethylene, 15 parts of polyethylene grafted maleic anhydride, 12 parts of modified monomer, 30 parts of wear-resistant filler (nano-alumina and nano-zinc oxide with a mass ratio of 2:1), 2 parts of antioxidant 1010, and 2 parts of lubricant (zinc stearate) were mixed and kneaded for 8 minutes, and then a sensitizer (trimethylolpropane trimethacrylate) was added and kneaded for 15 minutes. After the material was discharged, it was granulated and dried, and then extruded and coated on the surface of the polyvinyl chloride insulation layer through an extruder. After irradiation and cross-linking (irradiation dose of 12 Mrad), a wear-resistant medium voltage power cable was obtained. Wherein, the preparation process of the modified monomer is: S1: 12 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide were mixed with 60 parts of dichloromethane, stirred until completely dissolved, 8 parts of triethylamine were added, and stirring was continued for 20 minutes. After that, the mixture was cooled to 0°C, 5 parts of 2-azidoethanol were added, and 6 parts of carbon tetrachloride were added at 0°C. The mixture was stirred at room temperature overnight and post-treated to obtain intermediate A. S2: Mix 7 parts of acetylene dicarboxylic acid with 50 parts of toluene, stir and dissolve, then add 7 parts of allyl alcohol and finally add 0.3 parts of p-toluenesulfonic acid. Raise the temperature to 120°C and reflux for 10 hours. After the reaction is complete, cool to room temperature and post-treat to obtain intermediate B. S3: 12 parts of intermediate A, 8 parts of intermediate B, and 50 parts of 2-methyltetrahydrofuran were mixed and stirred until completely dissolved. The temperature was then raised to 90°C and refluxed for 24 hours. The reaction solution was added to hexane, precipitated, washed, and dried to obtain a modified monomer.

[0027] Example 3: A preparation process for a wear-resistant medium-voltage power cable is as follows: After extruding and coating the surface of the copper alloy conductor with a polyvinyl chloride insulation layer, 40 parts of ethylene-vinyl acetate copolymer, 30 parts of high-density polyethylene, 10 parts of polyethylene grafted maleic anhydride, 11 parts of a modified monomer, 25 parts of a wear-resistant filler (nano-alumina and nano-zinc oxide in a mass ratio of 2:1), 1.5 parts of an antioxidant 1010, and 1.5 parts of a lubricant (zinc stearate) were mixed and kneaded for 6 minutes. Then, a sensitizer (trimethylolpropane trimethacrylate) was added and kneaded for 12 minutes. After discharging, the material was granulated and dried, and then extruded and coated on the surface of the polyvinyl chloride insulation layer through an extruder. After irradiation and cross-linking (irradiation dose of 10 Mrad), a wear-resistant medium voltage power cable was obtained. Wherein, the preparation process of the modified monomer is: S1: 11 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide were mixed with 55 parts of dichloromethane and stirred until completely dissolved. 7.5 parts of triethylamine were added and stirring continued for 15 minutes. The mixture was then cooled to 0°C and 4.5 parts of 2-azidoethanol were added. 5.5 parts of carbon tetrachloride were then added at 0°C. After the addition was complete, the mixture was stirred at room temperature overnight and post-treated to obtain Intermediate A. S2: Mix 6.5 parts of acetylene dicarboxylic acid with 45 parts of toluene, stir and dissolve, then add 6.5 parts of allyl alcohol and finally add 0.35 parts of p-toluenesulfonic acid. Raise the temperature to 115°C and reflux for 9 hours. After the reaction is complete, cool to room temperature and post-treat to obtain intermediate B. S3: 11 parts of intermediate A, 7.5 parts of intermediate B, and 45 parts of 2-methyltetrahydrofuran were mixed and stirred until completely dissolved. The temperature was then raised to 85°C and refluxed for 24 hours. The reaction solution was added to hexane, precipitated, washed, and dried to obtain a modified monomer.

[0028] Comparative Example 1: No modified monomer was introduced, and the rest was the same as Example 3, specifically as follows: After the polyvinyl chloride insulation layer is extruded and coated on the surface of the copper alloy conductor, 40 parts of ethylene-vinyl acetate copolymer, 30 parts of high-density polyethylene, 10 parts of polyethylene grafted maleic anhydride, 25 parts of wear-resistant filler (nano-alumina and nano-zinc oxide with a mass ratio of 2:1), 1.5 parts of antioxidant 1010, and 1.5 parts of lubricant (zinc stearate) are mixed and kneaded for 6 minutes. Then, a sensitizer (trimethylolpropane trimethacrylate) is added and kneading is continued for 12 minutes. After discharging, the material is granulated and dried, and then extruded and coated on the surface of the polyvinyl chloride insulation layer through an extruder. After irradiation and cross-linking (irradiation dose of 10 Mrad), a wear-resistant medium-voltage power cable is obtained.

[0029] Comparative Example 2: The wear-resistant filler was replaced with an equal amount of silicon dioxide, and the rest was the same as in Example 3, as follows: After extruding and coating the polyvinyl chloride insulation layer on the surface of the copper alloy conductor, 40 parts of ethylene-vinyl acetate copolymer, 30 parts of high-density polyethylene, 10 parts of polyethylene grafted maleic anhydride, 11 parts of modified monomer, 25 parts of silicon dioxide, 1.5 parts of antioxidant 1010, and 1.5 parts of lubricant (zinc stearate) were mixed and kneaded for 6 minutes, and then a sensitizer (trimethylolpropane trimethacrylate) was added and kneaded for 12 minutes. After the material was discharged, it was granulated and dried, and then extruded and coated on the surface of the polyvinyl chloride insulation layer through an extruder. After irradiation and cross-linking (irradiation dose of 10 Mrad), a wear-resistant medium voltage power cable was obtained. Wherein, the preparation process of the modified monomer is: S1: 11 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide were mixed with 55 parts of dichloromethane and stirred until completely dissolved. 7.5 parts of triethylamine were added and stirring continued for 15 minutes. The mixture was then cooled to 0°C and 4.5 parts of 2-azidoethanol were added. 5.5 parts of carbon tetrachloride were then added at 0°C. After the addition was complete, the mixture was stirred at room temperature overnight and post-treated to obtain Intermediate A. S2: Mix 6.5 parts of acetylene dicarboxylic acid with 45 parts of toluene, stir and dissolve, then add 6.5 parts of allyl alcohol and finally add 0.35 parts of p-toluenesulfonic acid. Raise the temperature to 115°C and reflux for 9 hours. After the reaction is complete, cool to room temperature and post-treat to obtain intermediate B. S3: 11 parts of intermediate A, 7.5 parts of intermediate B, and 45 parts of 2-methyltetrahydrofuran were mixed and stirred until completely dissolved. The temperature was then raised to 85°C and refluxed for 24 hours. The reaction solution was added to hexane, precipitated, washed, and dried to obtain a modified monomer.

[0030] Detection experiment: The sheath layers of the wear-resistant medium-voltage power cables obtained in the examples and comparative examples were peeled off and the following tests were performed: (1) The tensile properties of the sheath layers of the embodiments and comparative examples were tested in accordance with the standard GB / T 1040.3-2006; (2) According to the standard GB / T 2406.3-2022, the sheath layers of the embodiment and the comparative example were subjected to high temperature tests to determine their oxygen indexes; (3) According to the standard GB / T 9867-2008, the relative volume wear of the sheath layer of the embodiment and the comparative example was measured respectively; The obtained data is shown in the following table: Table 1

[0031] Conclusion: The present invention chemically synthesizes a modified monomer containing a flame retardant structure and a triazole group, and applies it to the sheath layer of a wear-resistant medium-voltage power cable, thereby significantly improving the comprehensive performance of the cable.

[0032] The experimental data show that the sheath materials of Examples 1-3 have excellent performance in terms of tensile strength, oxygen index and wear resistance. The tensile strength reaches 24.7-25.9 MPa, the oxygen index is 36%-37%, and the relative volume wear is only 26-28 mm. 3 In contrast, the performance of the comparative example 1 without the introduction of the modified monomer was significantly reduced, with a tensile strength of only 14.5 MPa, an oxygen index of 22%, and a wear loss of 36 mm. 3; Although comparative example 2 introduces a modified monomer but replaces the wear-resistant filler with silica, its performance is better than comparative example 1, but still inferior to examples 1-3, because the surface of silica is mainly composed of silanol groups, which cannot form a similar strong coordination effect with the triazole ring, making the filler easy to agglomerate, reducing the relevant performance of the sheath material.

[0033] In summary, the introduction of modified monomers and the combination of nano-alumina and nano-zinc oxide as wear-resistant fillers jointly improve the mechanical properties, flame retardant effect and wear resistance of the cable sheath.

[0034] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A wear-resistant medium voltage power cable, characterized in that: The invention comprises a conductor, an insulating layer and a sheath layer which are arranged in sequence from the inside to the outside; the sheath layer comprises the following raw materials: by weight, 30-50 parts of ethylene-vinyl acetate copolymer, 20-40 parts of high-density polyethylene, 5-15 parts of polyethylene grafted maleic anhydride, 10-12 parts of modified monomer, 20-30 parts of wear-resistant filler, 1-2 parts of antioxidant, 1-2 parts of lubricant and 2-3 parts of sensitizer.

2. The wear-resistant medium voltage power cable according to claim 1, characterized in that: The preparation process of the modified monomer is: S1: Mix 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide with dichloromethane, stir until completely dissolved, add triethylamine, continue stirring for 10-20 minutes, then cool to 0°C, add 2-azidoethanol, and continue adding carbon tetrachloride at 0°C. Stir at room temperature overnight and post-treat to obtain intermediate A; S2: Mix acetylene dicarboxylic acid and toluene, stir to dissolve, add allyl alcohol, and finally add p-toluenesulfonic acid, raise the temperature to 110-120°C, reflux for 8-10 hours, cool to room temperature, and post-treat to obtain intermediate B; S3: Intermediate A, intermediate B, and 2-methyltetrahydrofuran are mixed and stirred until completely dissolved. The temperature is then raised to 80-90° C. and refluxed for 24 hours. The reaction solution is added to hexane, precipitated, washed, and dried to obtain a modified monomer.

3. The wear-resistant medium voltage power cable according to claim 2, characterized in that: The intermediate A raw materials include the following substances: by weight, 10-12 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 50-60 parts of dichloromethane, 7-8 parts of triethylamine, 4-5 parts of 2-azidoethanol, and 5-6 parts of carbon tetrachloride.

4. The wear-resistant medium voltage power cable according to claim 2, characterized in that: The raw materials of intermediate B include the following substances: 6-7 parts of acetylene dicarboxylic acid, 40-50 parts of toluene, 6-7 parts of allyl alcohol, and 0.2-0.3 parts of p-toluenesulfonic acid, by weight.

5. The wear-resistant medium voltage power cable according to claim 2, characterized in that: The modified monomer raw material comprises the following substances: by weight, 10-12 parts of intermediate A, 7-8 parts of intermediate B, and 40-50 parts of 2-methyltetrahydrofuran.

6. The wear-resistant medium voltage power cable according to claim 1, characterized in that: The wear-resistant filler comprises nano-aluminum oxide and nano-zinc oxide in a mass ratio of 2:

1.

7. The wear-resistant medium voltage power cable according to claim 1, characterized in that: The antioxidant includes one or both of antioxidant 1010 and antioxidant 168 .

8. The wear-resistant medium voltage power cable according to claim 1, characterized in that: The lubricant includes one or more of zinc stearate, calcium stearate, barium stearate or polyethylene wax.

9. The wear-resistant medium voltage power cable according to claim 1, characterized in that: The preparation process of the wear-resistant medium voltage power cable is as follows: After the insulation layer is extruded and coated on the surface of the conductor, ethylene-vinyl acetate copolymer, high-density polyethylene, polyethylene grafted maleic anhydride, modified monomer, wear-resistant filler, antioxidant, and lubricant are mixed and kneaded for 5-8 minutes, and then a sensitizer is added and kneaded for 10-15 minutes. After the material is discharged, it is granulated and dried, and then extruded through an extruder and coated on the surface of the insulation layer. After irradiation and cross-linking, a wear-resistant medium-voltage power cable is obtained.

10. The wear-resistant medium voltage power cable according to claim 9, characterized in that: During the radiation cross-linking, the radiation dose is 8 Mrad-12 Mrad.

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