High-toughness corrosion-resistant medium-voltage power cable

Abstract

The invention relates to the technical field of cables, and provides a high-toughness corrosion-resistant medium-voltage power cable, which comprises a conductor, and an insulating layer, a shielding layer, an armor layer and a sheath layer which are sequentially arranged outside the conductor, the sheath layer comprises the following components in parts by weight: 70-100 parts of polyvinyl chloride, 30-40 parts of nitrile rubber, 10-15 parts of a flame retardant, 15-20 parts of a plasticizer, 1-3 parts of an antioxidant, 5-10 parts of a filler, 2-4 parts of a heat stabilizer, 1-3 parts of a compatilizer and 0.5-2 parts of a cross-linking agent; the filler is prepared from the following raw materials in parts by weight: 100 parts of calcium carbonate, 20 to 24 parts of 2-ethylhexyl acrylate and 6 to 10 parts of acrylic acid. According to the technical scheme, the problem of poor corrosion resistance of the medium-voltage power cable in the prior art is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cable, in particular to a high-toughness corrosion-resistant medium-voltage power cable. BACKGROUND

[0002] As a core component of power transmission system, the medium-voltage power cable is widely used in urban power grids, industrial parks, and mining scenes, and its stable operation is directly related to the safety and reliability of power supply. With the rapid development of social economy, the application environment of medium-voltage power cables in various fields is becoming more and more severe, especially in the corrosion environment such as chemical industry park, coastal high-humidity and high-salt area, and saline-alkali soil. The cable sheath is in long-term contact with acid and alkali medium, salt mist and corrosive soil, which is prone to aging, cracking and swelling. The existing medium-voltage power cable sheath material has poor corrosion resistance, and the sheath is easy to lose toughness and break when used in a corrosive environment for a long time, thereby causing the cable insulation performance to decrease, leading to safety accidents such as short circuit and electric leakage, seriously affecting the stable operation of the power system, and greatly shortening the service life of the cable and increasing the power maintenance cost. Therefore, it has become a key technical problem to be solved in the current power cable industry to develop a medium-voltage power cable with high toughness and excellent corrosion resistance. SUMMARY

[0003] The present application provides a high-toughness corrosion-resistant medium-voltage power cable, which solves the problem of poor corrosion resistance of the medium-voltage power cable in the related art.

[0004] The technical scheme of the present application is as follows: The present application provides a high-toughness corrosion-resistant medium-voltage power cable, which includes a conductor and an insulating layer, a shielding layer, an armor layer, and a sheath layer arranged in sequence outside the conductor. The sheath layer includes the following components by weight: polyvinyl chloride 70-100 parts, nitrile rubber 30-40 parts, flame retardant 10-15 parts, plasticizer 15-20 parts, antioxidant 1-3 parts, filler 5-10 parts, thermal stabilizer 2-4 parts, compatibilizer 1-3 parts, and crosslinking agent 0.5-2 parts. The filler includes the following components by weight: calcium carbonate 100 parts, 2-ethylhexyl acrylate 20-24 parts, and acrylic acid 6-10 parts.

[0005] As a further technical solution, the mass ratio of 2-ethylhexyl acrylate to acrylic acid is 3:1.

[0006] This invention specifies a 3:1 mass ratio of 2-ethylhexyl acrylate to acrylic acid in the sheath layer of a high-toughness, corrosion-resistant medium-voltage power cable, which further enhances the toughness and corrosion resistance of the sheath layer. The long-chain alkyl side groups of 2-ethylhexyl acrylate are highly hydrophobic and have good compatibility with the PVC-N-butadiene rubber matrix. It can form a hydrophobic layer on the calcium carbonate surface, reducing filler agglomeration and enhancing the bonding force between the filler and the matrix. However, when only 2-ethylhexyl acrylate is used to coat calcium carbonate, the steric hindrance effect of its long-chain alkyl groups can cause uneven coating of the calcium carbonate powder. The addition of acrylic acid helps improve the uniformity of the calcium carbonate powder coating. At this ratio, the two can work synergistically to form a uniform hydrophobic coating layer on the calcium carbonate surface, allowing the filler to be more evenly dispersed in the sheath layer matrix, thereby further improving the toughness and corrosion resistance of the sheath layer.

[0007] As a further technical solution, the method for preparing the filler includes the following steps: A1. Disperse calcium carbonate in a solvent, add silane coupling agent, mix, filter, and dry to obtain pretreated calcium carbonate; A2. Disperse 2-ethylhexyl acrylate and sodium dodecyl sulfate in water, then add pretreated calcium carbonate and mix to obtain a suspension; A3. Add an aqueous solution of acrylic acid and an aqueous solution of initiator to the suspension, mix, filter, wash with water, and dry to obtain the filler.

[0008] As a further technical solution, in step A1, the silane coupling agent is silane coupling agent KH-570.

[0009] As a further technical solution, in step A1, the mass-to-volume ratio of calcium carbonate to solvent is 1g:11~13mL.

[0010] As a further technical solution, in step A1, the mass of the silane coupling agent KH-570 is 3% to 4% of the mass of the calcium carbonate.

[0011] As a further technical solution, in step A1, the solvent is an ethanol aqueous solution with a mass fraction of 85%.

[0012] As a further technical solution, in step A1, the mixing temperature is 45~55℃ and the time is 2~4h.

[0013] As a further technical solution, in step A2, the mass of sodium dodecyl sulfate is 1% to 2% of the mass of calcium carbonate.

[0014] As a further technical solution, in step A3, the mass fraction of the acrylic acid aqueous solution is 7.5%.

[0015] As a further technical solution, in step A3, the initiator aqueous solution is an ammonium persulfate aqueous solution, the mass fraction of the ammonium persulfate aqueous solution is 2.5%, and the mass of the ammonium persulfate in the ammonium persulfate aqueous solution is 10% of the mass of the calcium carbonate.

[0016] As a further technical solution, in step A3, the mixing temperature is 70~80℃ and the time is 5~7h.

[0017] As a further technical solution, the nitrile rubber includes a first nitrile rubber and a second nitrile rubber; the first nitrile rubber and the second nitrile rubber have different acrylonitrile content.

[0018] As a further technical solution, the acrylonitrile content of the first nitrile rubber is 40.5% by mass; the acrylonitrile content of the second nitrile rubber is 29% by mass.

[0019] This invention employs a blend of a first nitrile butadiene rubber (40.5% by mass) and a second nitrile butadiene rubber (29% by mass) added to the sheath layer of medium-voltage power cables, which can improve the toughness of the cable sheath layer. The second nitrile butadiene rubber has a higher proportion of flexible butadiene segments in its molecular chain, providing good toughness to the sheath layer material. Meanwhile, the first nitrile butadiene rubber, due to its stronger polarity, has better compatibility with polyvinyl chloride (PVC) and can be uniformly dispersed in PVC. Furthermore, the molecular chain entanglement between the two nitrile butadiene rubbers further enhances the interfacial bonding between the second nitrile butadiene rubber and PVC, thereby synergistically improving the toughness of the cable sheath layer.

[0020] As a further technical solution, the mass ratio of the first nitrile rubber to the second nitrile rubber is 1.5~2.5:1.

[0021] As a further technical solution, the flame retardant includes one or two of magnesium hydroxide and aluminum hydroxide; the heat stabilizer is a calcium-zinc composite stabilizer; and the compatibilizer is an ethylene-vinyl acetate copolymer grafted with maleic anhydride.

[0022] As a further technical solution, the antioxidant includes one or more of antioxidant 1010, antioxidant 168 and antioxidant RD; the crosslinking agent includes one or more of dicumyl peroxide, benzoyl peroxide and bis-tert-butyldicumyl peroxide.

[0023] As a further technical solution, the plasticizer includes one or more of dioctyl adipate, diisononyl adipate, and trioctyl trimellitate.

[0024] This invention also proposes a method for preparing a high-toughness, corrosion-resistant medium-voltage power cable, comprising the following steps: S1. Extruding insulating material around the conductor to form an insulating layer; S2. Weave the shielding material onto the outside of the insulation layer to form a shielding layer; S3. Wrap the armor layer material around the shielding layer to form the armor layer; S4. Mix the components of the sheath layer, extrude them onto the outside of the armor layer, crosslink them to form the sheath layer, and obtain a high-toughness, corrosion-resistant medium-voltage power cable.

[0025] As a further technical solution, the conductor is a copper conductor; the insulating layer material is polyethylene; the shielding layer material is tin-plated copper wire; and the armor layer material is galvanized steel strip.

[0026] The working principle and beneficial effects of this invention are as follows: This invention relates to a high-toughness, corrosion-resistant medium-voltage power cable. It utilizes a filler prepared from calcium carbonate, 2-ethylhexyl acrylate, and acrylic acid as raw materials to enhance the toughness and corrosion resistance of the sheath layer. Existing technologies often use calcium carbonate as a filler to improve corrosion resistance; however, calcium carbonate powder, due to its high surface energy, is prone to agglomeration. This not only hinders its ability to improve corrosion resistance but also creates stress concentration points, thus affecting the cable sheath's toughness. The filler prepared from calcium carbonate, 2-ethylhexyl acrylate, and acrylic acid in this invention reduces the agglomeration tendency of calcium carbonate and improves its dispersibility in the sheath matrix, thereby enhancing the toughness and corrosion resistance of the medium-voltage power cable sheath. Detailed Implementation

[0027] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0028] In the following examples and comparative examples, the polyvinyl chloride (PVC-SG5) was used; the first nitrile rubber had an acrylonitrile content of 40.5% and was graded Nandi 1051; the second nitrile rubber had an acrylonitrile content of 29% and was graded Nandi 1043; magnesium hydroxide had a particle size of 3 μm; aluminum hydroxide had a particle size of 3 μm; calcium carbonate had a particle size of 1 μm; and galvanized steel strip had a thickness of 0.5 mm.

[0029] Example 1 A high-toughness, corrosion-resistant medium-voltage power cable includes a conductor and an insulation layer, a shielding layer, an armor layer, and a sheath layer sequentially disposed outside the conductor. The sheath layer comprises the following components in parts by weight: 70 parts polyvinyl chloride, 30 parts nitrile rubber, 10 parts magnesium hydroxide, 15 parts dioctyl adipate, 1 part antioxidant 1010, 5 parts filler, 2 parts calcium-zinc composite stabilizer, 1 part ethylene-vinyl acetate copolymer grafted with maleic anhydride, and 0.5 parts dicumyl peroxide; the nitrile rubber is a first type of nitrile rubber. The method for preparing the filler includes the following steps: A1. Disperse 100 parts of calcium carbonate in an 85% ethanol aqueous solution, add 3 parts of silane coupling agent KH-570, mix at 45℃ for 4 hours, filter and dry to obtain pretreated calcium carbonate; the mass-volume ratio of calcium carbonate to ethanol aqueous solution is 1g:12mL. A2. Disperse 20 parts of 2-ethylhexyl acrylate and 1.5 parts of sodium dodecyl sulfate in 100 parts of water, then add pretreated calcium carbonate and mix to obtain a suspension; A3. Add acrylic acid aqueous solution and ammonium persulfate aqueous solution to the suspension, mix at 70℃ for 7 hours, filter, wash with water, and dry to obtain the filler; the mass fraction of the ammonium persulfate aqueous solution is 2.5%, of which the weight of ammonium persulfate in the ammonium persulfate aqueous solution is 10 parts; the mass fraction of the acrylic acid aqueous solution is 7.5%, of which the weight of acrylic acid in the acrylic acid aqueous solution is 10 parts; A method for preparing a high-toughness, corrosion-resistant medium-voltage power cable includes the following steps: S1. Polyethylene is extruded around a copper conductor and cross-linked to form an insulating layer; S2. Braid tin-plated copper wires onto the outside of the insulation layer to form a shielding layer; S3. Wrap the galvanized steel strip around the shielding layer to form an armor layer; S4. Mix the components of the sheath layer, extrude them onto the outside of the armor layer, crosslink them to form the sheath layer, and obtain a high-toughness, corrosion-resistant medium-voltage power cable.

[0030] Example 2 A high-toughness, corrosion-resistant medium-voltage power cable includes a conductor and an insulation layer, a shielding layer, an armor layer, and a sheath layer sequentially disposed outside the conductor. The sheath layer comprises the following components in parts by weight: 85 parts polyvinyl chloride, 35 parts nitrile rubber, 13 parts aluminum hydroxide, 18 parts diisononyl adipate, 2 parts antioxidant 168, 8 parts filler, 3 parts calcium-zinc composite stabilizer, 2 parts ethylene-vinyl acetate copolymer grafted with maleic anhydride, and 1 part benzoyl peroxide; the nitrile rubber is a first type of nitrile rubber. The method for preparing the filler includes the following steps: A1. Disperse 100 parts of calcium carbonate in an 85% ethanol aqueous solution, add 3.5 parts of silane coupling agent KH-570, mix at 50℃ for 3 hours, filter and dry to obtain pretreated calcium carbonate; the mass-volume ratio of calcium carbonate to ethanol aqueous solution is 1g:12mL. A2. Disperse 20 parts of 2-ethylhexyl acrylate and 1 part of sodium dodecyl sulfate in 100 parts of water, then add pretreated calcium carbonate and mix to obtain a suspension; A3. Add acrylic acid aqueous solution and ammonium persulfate aqueous solution to the suspension, mix at 75℃ for 6 hours, filter, wash with water, and dry to obtain the filler; the mass fraction of the ammonium persulfate aqueous solution is 2.5%, of which the weight of ammonium persulfate is 10 parts; the mass fraction of the acrylic acid aqueous solution is 7.5%, of which the weight of acrylic acid is 10 parts. The preparation method of the high-toughness, corrosion-resistant medium-voltage power cable is the same as that in Example 1.

[0031] Example 3 A high-toughness, corrosion-resistant medium-voltage power cable includes a conductor and an insulation layer, a shielding layer, an armor layer, and a sheath layer sequentially disposed outside the conductor. The sheath layer comprises the following components in parts by weight: 100 parts polyvinyl chloride, 40 parts nitrile rubber, 15 parts aluminum hydroxide, 20 parts trioctyl trimellitate, 3 parts antioxidant RD, 10 parts filler, 4 parts calcium-zinc composite stabilizer, 3 parts ethylene-vinyl acetate copolymer grafted with maleic anhydride, and 2 parts di-tert-butyl peroxide diisopropylbenzene; the nitrile rubber is a first type of nitrile rubber. The method for preparing the filler includes the following steps: A1. Disperse 100 parts of calcium carbonate in an 85% (w / w) aqueous ethanol solution, add 4 parts of silane coupling agent KH-570, mix at 55°C for 2 hours, filter and dry to obtain pretreated calcium carbonate; the mass-volume ratio of calcium carbonate to aqueous ethanol solution is 1 g: 12 mL. A2. Disperse 20 parts of 2-ethylhexyl acrylate and 2 parts of sodium dodecyl sulfate in 100 parts of water, then add pretreated calcium carbonate and mix to obtain a suspension; A3. Add acrylic acid aqueous solution and ammonium persulfate aqueous solution to the suspension, mix at 80℃ for 5 hours, filter, wash with water, and dry to obtain the filler; the mass fraction of ammonium persulfate aqueous solution is 2.5%, of which ammonium persulfate is 10 parts by weight; the mass fraction of acrylic acid aqueous solution is 7.5%, of which acrylic acid is 10 parts by weight. The preparation method of the high-toughness, corrosion-resistant medium-voltage power cable is the same as that in Example 1.

[0032] Example 4 A high-toughness, corrosion-resistant medium-voltage power cable includes a conductor and an insulation layer, a shielding layer, an armor layer, and a sheath layer sequentially disposed outside the conductor. The sheath layer comprises the following components in parts by weight: 70 parts polyvinyl chloride, 30 parts nitrile rubber, 10 parts magnesium hydroxide, 15 parts dioctyl adipate, 1 part antioxidant 1010, 5 parts filler, 2 parts calcium-zinc composite stabilizer, 1 part ethylene-vinyl acetate copolymer grafted with maleic anhydride, and 0.5 parts dicumyl peroxide; the nitrile rubber is a first type of nitrile rubber. The method for preparing the filler includes the following steps: A1. Disperse 100 parts of calcium carbonate in an 85% ethanol aqueous solution, add 3 parts of silane coupling agent KH-570, mix at 45℃ for 4 hours, filter and dry to obtain pretreated calcium carbonate; the mass-volume ratio of calcium carbonate to ethanol aqueous solution is 1g:12mL. A2. Disperse 22.5 parts of 2-ethylhexyl acrylate and 1.5 parts of sodium dodecyl sulfate in 100 parts of water, then add pretreated calcium carbonate and mix to obtain a suspension; A3. Add acrylic acid aqueous solution and ammonium persulfate aqueous solution to the suspension, mix at 70℃ for 7 hours, filter, wash with water, and dry to obtain the filler; the mass fraction of ammonium persulfate aqueous solution is 2.5%, of which the weight of ammonium persulfate in the ammonium persulfate aqueous solution is 10 parts; the mass fraction of acrylic acid aqueous solution is 7.5%, of which the weight of acrylic acid in the acrylic acid aqueous solution is 7.5 parts; The preparation method of the high-toughness, corrosion-resistant medium-voltage power cable is the same as that in Example 1.

[0033] Example 5 A high-toughness, corrosion-resistant medium-voltage power cable includes a conductor and an insulation layer, a shielding layer, an armor layer, and a sheath layer sequentially disposed outside the conductor. The sheath layer comprises the following components in parts by weight: 70 parts polyvinyl chloride, 30 parts nitrile rubber, 10 parts magnesium hydroxide, 15 parts dioctyl adipate, 1 part antioxidant 1010, 5 parts filler, 2 parts calcium-zinc composite stabilizer, 1 part ethylene-vinyl acetate copolymer grafted with maleic anhydride, and 0.5 parts dicumyl peroxide; the nitrile rubber is a first type of nitrile rubber. The method for preparing the filler includes the following steps: A1. Disperse 100 parts of calcium carbonate in an 85% ethanol aqueous solution, add 3 parts of silane coupling agent KH-570, mix at 45℃ for 4 hours, filter and dry to obtain pretreated calcium carbonate; the mass-volume ratio of calcium carbonate to ethanol aqueous solution is 1g:12mL. A2. Disperse 24 parts of 2-ethylhexyl acrylate and 1.5 parts of sodium dodecyl sulfate in 100 parts of water, and then add pretreated calcium carbonate to obtain a suspension; A3. Add acrylic acid aqueous solution and ammonium persulfate aqueous solution to the suspension, mix at 70℃ for 7 hours, filter, wash with water, and dry to obtain the filler; the mass fraction of the ammonium persulfate aqueous solution is 2.5%, of which the weight part of ammonium persulfate in the ammonium persulfate aqueous solution is 10 parts; the mass fraction of the acrylic acid aqueous solution is 7.5%, of which the weight part of acrylic acid in the acrylic acid aqueous solution is 6 parts; The preparation method of the high-toughness, corrosion-resistant medium-voltage power cable is the same as that in Example 1.

[0034] Example 6 A high-toughness, corrosion-resistant medium-voltage power cable includes a conductor and an insulation layer, a shielding layer, an armor layer, and a sheath layer sequentially disposed outside the conductor. The sheath layer comprises the following components in parts by weight: 70 parts polyvinyl chloride, 30 parts nitrile rubber, 10 parts magnesium hydroxide, 15 parts dioctyl adipate, 1 part antioxidant 1010, 5 parts filler, 2 parts calcium-zinc composite stabilizer, 1 part ethylene-vinyl acetate copolymer grafted with maleic anhydride, and 0.5 parts dicumyl peroxide. The nitrile rubber is composed of a first nitrile rubber and a second nitrile rubber in a mass ratio of 1.5:1. The method for preparing the filler includes the following steps: A1. Disperse 100 parts of calcium carbonate in an 85% ethanol aqueous solution, add 3 parts of silane coupling agent KH-570, mix at 45℃ for 4 hours, filter and dry to obtain pretreated calcium carbonate; the mass-volume ratio of calcium carbonate to ethanol aqueous solution is 1g:12mL. A2. Disperse 20 parts of 2-ethylhexyl acrylate and 1.5 parts of sodium dodecyl sulfate in 100 parts of water, and then add pretreated calcium carbonate to obtain a suspension; A3. Add acrylic acid aqueous solution and ammonium persulfate aqueous solution to the suspension, mix at 70℃ for 7 hours, filter, wash with water, and dry to obtain the filler; the mass fraction of the ammonium persulfate aqueous solution is 2.5%, of which the weight of ammonium persulfate in the ammonium persulfate aqueous solution is 10 parts; the mass fraction of the acrylic acid aqueous solution is 7.5%, of which the weight of acrylic acid in the acrylic acid aqueous solution is 10 parts; The preparation method of the high-toughness, corrosion-resistant medium-voltage power cable is the same as that in Example 1.

[0035] Example 7 A high-toughness, corrosion-resistant medium-voltage power cable includes a conductor and an insulation layer, a shielding layer, an armor layer, and a sheath layer sequentially disposed outside the conductor. The sheath layer comprises the following components in parts by weight: 70 parts polyvinyl chloride, 30 parts nitrile rubber, 10 parts magnesium hydroxide, 15 parts dioctyl adipate, 1 part antioxidant 1010, 5 parts filler, 2 parts calcium-zinc composite stabilizer, 1 part ethylene-vinyl acetate copolymer grafted with maleic anhydride, and 0.5 parts dicumyl peroxide. The nitrile rubber is composed of a first nitrile rubber and a second nitrile rubber in a mass ratio of 2:1. The method for preparing the filler includes the following steps: A1. Disperse 100 parts of calcium carbonate in an 85% ethanol aqueous solution, add 3 parts of silane coupling agent KH-570, mix at 45℃ for 4 hours, filter and dry to obtain pretreated calcium carbonate; the mass-volume ratio of calcium carbonate to ethanol aqueous solution is 1g:12mL. A2. Disperse 20 parts of 2-ethylhexyl acrylate and 1.5 parts of sodium dodecyl sulfate in 100 parts of water, and then add pretreated calcium carbonate to obtain a suspension; A3. Add acrylic acid aqueous solution and ammonium persulfate aqueous solution to the suspension, mix at 70℃ for 7 hours, filter, wash with water, and dry to obtain the filler; the mass fraction of the ammonium persulfate aqueous solution is 2.5%, of which the weight of ammonium persulfate in the ammonium persulfate aqueous solution is 10 parts; the mass fraction of the acrylic acid aqueous solution is 7.5%, of which the weight of acrylic acid in the acrylic acid aqueous solution is 10 parts; The preparation method of the high-toughness, corrosion-resistant medium-voltage power cable is the same as that in Example 1.

[0036] Example 8 A high-toughness, corrosion-resistant medium-voltage power cable includes a conductor and an insulation layer, a shielding layer, an armor layer, and a sheath layer sequentially disposed outside the conductor. The sheath layer comprises the following components in parts by weight: 70 parts polyvinyl chloride, 30 parts nitrile rubber, 10 parts magnesium hydroxide, 15 parts dioctyl adipate, 1 part antioxidant 1010, 5 parts filler, 2 parts calcium-zinc composite stabilizer, 1 part ethylene-vinyl acetate copolymer grafted with maleic anhydride, and 0.5 parts dicumyl peroxide. The nitrile rubber is composed of a first nitrile rubber and a second nitrile rubber in a mass ratio of 2.5:1. The method for preparing the filler includes the following steps: A1. Disperse 100 parts of calcium carbonate in an 85% ethanol aqueous solution, add 3 parts of silane coupling agent KH-570, mix at 45℃ for 4 hours, filter and dry to obtain pretreated calcium carbonate; the mass-volume ratio of calcium carbonate to ethanol aqueous solution is 1g:12mL. A2. Disperse 20 parts of 2-ethylhexyl acrylate and 1.5 parts of sodium dodecyl sulfate in 100 parts of water, and then add pretreated calcium carbonate to obtain a suspension; A3. Add acrylic acid aqueous solution and ammonium persulfate aqueous solution to the suspension, mix at 70℃ for 7 hours, filter, wash with water, and dry to obtain the filler; the mass fraction of the ammonium persulfate aqueous solution is 2.5%, of which the weight of ammonium persulfate in the ammonium persulfate aqueous solution is 10 parts; the mass fraction of the acrylic acid aqueous solution is 7.5%, of which the weight of acrylic acid in the acrylic acid aqueous solution is 10 parts; The preparation method of the high-toughness, corrosion-resistant medium-voltage power cable is the same as that in Example 1.

[0037] Example 9 A high-toughness, corrosion-resistant medium-voltage power cable includes a conductor and an insulation layer, a shielding layer, an armor layer, and a sheath layer sequentially disposed outside the conductor. The sheath layer comprises the following components in parts by weight: 70 parts polyvinyl chloride, 30 parts nitrile rubber, 10 parts magnesium hydroxide, 15 parts dioctyl adipate, 1 part antioxidant 1010, 5 parts filler, 2 parts calcium-zinc composite stabilizer, 1 part ethylene-vinyl acetate copolymer grafted with maleic anhydride, and 0.5 parts dicumyl peroxide; the nitrile rubber is a second type of nitrile rubber. The method for preparing the filler includes the following steps: A1. Disperse 100 parts of calcium carbonate in an 85% ethanol aqueous solution, add 3 parts of silane coupling agent KH-570, mix at 45℃ for 4 hours, filter and dry to obtain pretreated calcium carbonate; the mass-volume ratio of calcium carbonate to ethanol aqueous solution is 1g:12mL. A2. Disperse 20 parts of 2-ethylhexyl acrylate and 1.5 parts of sodium dodecyl sulfate in 100 parts of water, and then add pretreated calcium carbonate to obtain a suspension; A3. Add acrylic acid aqueous solution and ammonium persulfate aqueous solution to the suspension, mix at 70℃ for 7 hours, filter, wash with water, and dry to obtain the filler; the mass fraction of the ammonium persulfate aqueous solution is 2.5%, of which the weight of ammonium persulfate in the ammonium persulfate aqueous solution is 10 parts; the mass fraction of the acrylic acid aqueous solution is 7.5%, of which the weight of acrylic acid in the acrylic acid aqueous solution is 10 parts; The preparation method of the high-toughness, corrosion-resistant medium-voltage power cable is the same as that in Example 1.

[0038] Comparative Example 1 A high-toughness, corrosion-resistant medium-voltage power cable includes a conductor and an insulation layer, a shielding layer, an armor layer, and a sheath layer sequentially disposed outside the conductor. The sheath layer comprises the following components in parts by weight: 70 parts polyvinyl chloride, 30 parts nitrile rubber, 10 parts magnesium hydroxide, 15 parts dioctyl adipate, 1 part antioxidant 1010, 5 parts calcium carbonate, 2 parts calcium-zinc composite stabilizer, 1 part ethylene-vinyl acetate copolymer grafted with maleic anhydride, and 0.5 parts dicumyl peroxide; the nitrile rubber is a first type of nitrile rubber. The preparation method of the high-toughness, corrosion-resistant medium-voltage power cable is the same as that in Example 1.

[0039] Experimental Example 1. Corrosion resistance test: The sheaths of the medium-voltage power cables prepared in Examples 1-5 and Comparative Example 1 were immersed in a 20wt% sodium hydroxide solution for 30 days. The impact strength of the sheaths before and after immersion was tested according to the test method specified in standard GB / T 1843-2008 "Determination of Impact Strength of Plastic Cantilever Beams". The sample size was 80×10×4mm and the type was an unnotched sample. 2. Impact strength test: The sheath layer of the medium-voltage power cable prepared in Examples 1, 6-9 was tested for impact strength according to the test method specified in standard GB / T 1843-2008 "Determination of Impact Strength of Plastic Cantilever Beams"; the sample size was 80×10×4mm; the type was unnotched sample; The test results are shown in Tables 1 and 2: Table 1. Test results of corrosion resistance of medium voltage power cable sheath.

[0040] The data in Table 1 show that the addition of fillers prepared from calcium carbonate, 2-ethylhexyl acrylate and acrylic acid can improve the impact strength and corrosion resistance of the medium-voltage power cable sheath layer of this invention.

[0041] Table 2. Impact Strength Test Results of Medium Voltage Power Cable Sheath

[0042] The data in Table 2 show that the addition of nitrile rubber composed of first and second nitrile rubbers with different acrylonitrile mass contents can further improve the impact strength of the medium-voltage power cable sheath layer of the present invention, thereby further improving the toughness of the medium-voltage power cable sheath layer.

[0043] The above are merely 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 within the protection scope of the present invention.

Claims

1. A high-toughness, corrosion-resistant medium-voltage power cable, characterized in that, It includes a conductor and an insulating layer, a shielding layer, an armor layer, and a sheath layer sequentially disposed outside the conductor; the sheath layer comprises the following components in parts by weight: 70-100 parts polyvinyl chloride, 30-40 parts nitrile rubber, 10-15 parts flame retardant, 15-20 parts plasticizer, 1-3 parts antioxidant, 5-10 parts filler, 2-4 parts heat stabilizer, 1-3 parts compatibilizer, and 0.5-2 parts crosslinking agent; The filler comprises the following raw materials in parts by weight: 100 parts calcium carbonate, 20-24 parts 2-ethylhexyl acrylate, and 6-10 parts acrylic acid.

2. The high-toughness, corrosion-resistant medium-voltage power cable according to claim 1, characterized in that, The mass ratio of 2-ethylhexyl acrylate to acrylic acid is 3:

1.

3. The high-toughness, corrosion-resistant medium-voltage power cable according to claim 1, characterized in that, The method for preparing the filler includes the following steps: A1. Disperse calcium carbonate in a solvent, add silane coupling agent, mix, filter, and dry to obtain pretreated calcium carbonate; A2. Disperse 2-ethylhexyl acrylate and sodium dodecyl sulfate in water, then add pretreated calcium carbonate and mix to obtain a suspension; A3. Add an aqueous solution of acrylic acid and an aqueous solution of initiator to the suspension, mix, filter, wash with water, and dry to obtain the filler.

4. The high-toughness, corrosion-resistant medium-voltage power cable according to claim 3, characterized in that, In step A1, the silane coupling agent is silane coupling agent KH-570.

5. A high-toughness, corrosion-resistant medium-voltage power cable according to claim 3, characterized in that, In step A3, the initiator aqueous solution is an ammonium persulfate aqueous solution.

6. The high-toughness, corrosion-resistant medium-voltage power cable according to claim 1, characterized in that, The nitrile rubber includes a first nitrile rubber and a second nitrile rubber; the first nitrile rubber and the second nitrile rubber have different acrylonitrile content.

7. A high-toughness, corrosion-resistant medium-voltage power cable according to claim 6, characterized in that, The first nitrile rubber has an acrylonitrile content of 40.5% by mass; the second nitrile rubber has an acrylonitrile content of 29% by mass.

8. A high-toughness, corrosion-resistant medium-voltage power cable according to claim 7, characterized in that, The mass ratio of the first nitrile rubber to the second nitrile rubber is 1.5~2.5:

1.

9. A high-toughness, corrosion-resistant medium-voltage power cable according to claim 1, characterized in that, The flame retardant includes one or two of magnesium hydroxide and aluminum hydroxide; the heat stabilizer is a calcium-zinc composite stabilizer; and the compatibilizer is an ethylene-vinyl acetate copolymer grafted with maleic anhydride.

10. A high-toughness, corrosion-resistant medium-voltage power cable according to claim 1, characterized in that, The antioxidant includes one or more of antioxidant 1010, antioxidant 168, and antioxidant RD; the plasticizer includes one or more of dioctyl adipate, diisononyl adipate, and trioctyl trimellitate.

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