Aluminum alloy medium voltage power cable and method for manufacturing the same

Abstract

This invention relates to the field of cable technology and proposes an aluminum alloy medium-voltage power cable and its manufacturing method. The aluminum alloy medium-voltage power cable comprises, from the inside out, a conductor, an insulation layer, an armor layer, and a sheath layer; the conductor is an aluminum alloy tightly stranded conductor; the sheath layer comprises the following components by weight: 70-80 parts EPDM rubber, 20-30 parts styrene-butadiene rubber, 30-40 parts inorganic filler, 7-12 parts naphthenic oil, 2-2.5 parts vulcanizing agent, 2.4-3 parts vulcanization accelerator, 1.5-2 parts stearic acid, 4-5 parts zinc oxide, 0.8-1.5 parts silane coupling agent, and 1.5-3 parts antioxidant; the inorganic filler includes sepiolite fiber-loaded magnesium iron hydrotalcite. The sheath layer material provided by this invention solves the technical problem of poor tear resistance in existing aluminum alloy medium-voltage power cables.

Description

Technical Field

[0001] This invention relates to the field of cable technology, specifically to an aluminum alloy medium-voltage power cable and its manufacturing method. Background Technology

[0002] Aluminum alloy medium-voltage power cables are core power transmission components in urban power grids, industrial power distribution, and rail transportation. Their structural stability, mechanical properties, and service life directly determine the safe and reliable operation of power transmission systems. The cable sheath, as a crucial outer layer resisting external mechanical damage, must possess excellent tear resistance. Conversely, if the sheath has poor tear resistance, the cable is prone to scratches, tears, and cracks during installation and long-term operation, leading to moisture and impurities intruding, causing insulation aging due to moisture, breakdown, and short circuits, thus reducing the cable's service life.

[0003] Currently, medium-voltage cable sheaths mostly use elastomer materials such as EPDM rubber and styrene-butadiene rubber, with mechanical properties improved by adding conventional inorganic fillers. However, traditional inorganic fillers have poor interfacial compatibility with the rubber matrix, easily agglomerating and forming stress concentration points, leading to cracks in the sheath under bending, dragging, and compression conditions. Secondly, single fillers have limited ability to inhibit crack propagation and insufficient improvement in tear resistance, making it difficult to meet the long-term service requirements in complex laying environments. Therefore, there is an urgent need to develop an aluminum alloy medium-voltage power cable with good tear resistance. Summary of the Invention

[0004] To address the above technical problems, this invention provides an aluminum alloy medium-voltage power cable and its preparation method. The tear strength of the sheath layer of the aluminum alloy medium-voltage power cable provided by this invention reaches more than 41KN / m, exhibiting excellent tear resistance.

[0005] The specific technical solution of the present invention is as follows: According to one aspect of the present invention, an aluminum alloy medium-voltage power cable is provided, comprising, from the inside out, a conductor, an insulation layer, an armor layer, and a sheath layer; The conductor is a tightly pressed stranded aluminum alloy conductor; The sheath layer comprises the following components by weight: 70-80 parts of EPDM rubber, 20-30 parts of styrene-butadiene rubber, 30-40 parts of inorganic filler, 7-12 parts of naphthenic oil, 2-2.5 parts of vulcanizing agent, 2.4-3 parts of vulcanization accelerator, 1.5-2 parts of stearic acid, 4-5 parts of zinc oxide, 0.8-1.5 parts of silane coupling agent, and 1.5-3 parts of antioxidant; The inorganic filler includes sepiolite fiber-loaded magnesium-iron hydrotalcite.

[0006] In the above technical solution, the compaction coefficient of the aluminum alloy tightly stranded conductor is 0.9~0.92.

[0007] In the above technical solution, the material of the armor layer is galvanized steel strip.

[0008] In the above technical solution, the preparation method of the sepiolite fiber-supported magnesium-iron hydrotalcite includes the following steps: Ferric chloride hexahydrate and magnesium chloride hexahydrate were dissolved in water, sepiolite fibers were added, and then sodium hydroxide solution was added to adjust the pH to 11-12. The resulting solution system was transferred to a reactor for hydrothermal reaction, centrifugation and washing were performed to obtain a solid, which was then dried to obtain the sepiolite fiber-supported magnesium-iron hydrotalcite.

[0009] In the above technical solution, the mass ratio of ferric chloride hexahydrate to magnesium chloride hexahydrate is 2~3:6; The mass ratio of magnesium chloride hexahydrate to sepiolite fiber is 6:1.4~1.7.

[0010] In the above technical solution, the temperature of the hydrothermal reaction is 170~190℃, and the time of the hydrothermal reaction is 4~5h.

[0011] In the above technical solution, the inorganic filler also includes layered inorganic filler.

[0012] In the above technical solution, the mass ratio of the sepiolite fiber-loaded magnesium-iron hydrotalcite to the lamellar inorganic filler is 2.2~3:1.

[0013] In the above technical solution, the layered inorganic filler includes one or more of hydrotalcite, montmorillonite, talc powder, and sericite.

[0014] In the above technical solution, the lamellar inorganic filler is sericite.

[0015] In the above technical solution, the vulcanizing agent includes sulfur; The vulcanization accelerator includes one or more of accelerator M, accelerator DM, accelerator CZ, and accelerator TMTD.

[0016] According to another aspect of the present invention, the present invention also provides a method for preparing the above-mentioned aluminum alloy medium-voltage power cable, comprising the following steps: S1. Compactly twist aluminum alloy monofilaments together to obtain a conductor; S2. Extruding the insulating material and coating it onto the outer surface of the conductor to obtain the insulating layer; S3. Wrap the armor layer material around the outer surface of the insulation layer to obtain the armor layer; S4. The components of the sheath layer are proportioned according to the weight ratio, mixed evenly, and then subjected to intensive mixing to obtain the sheath material. The sheath material is extruded and coated onto the outer surface of the armor layer. After vulcanization, cross-linking, cooling and shaping, and traction winding, the aluminum alloy medium-voltage power cable is obtained.

[0017] Compared with existing technologies, this invention provides an aluminum alloy medium-voltage power cable. By adding sepiolite fiber-loaded magnesium-iron hydrotalcite (Mg-Fe) to the cable sheath layer, the tear strength of the sheath layer is increased to over 41 KN / m, thereby improving the tear resistance of the aluminum alloy medium-voltage power cable. The reasons for this are likely as follows: First, the sepiolite fiber-loaded Mg-Fe hydrotalcite can improve the self-agglomeration problem of the nanosheets (Mg-Fe hydrotalcite). Compared with adding sepiolite fiber and Mg-Fe hydrotalcite through direct physical blending, this composite filler is more uniformly dispersed in the rubber matrix, without local agglomeration defects, thus reducing stress concentration points. Second, the sepiolite fiber, as the main skeleton for stress transmission, bears and disperses external forces, while the Mg-Fe hydrotalcite loaded on it can effectively deflect and blunt the crack propagation path, causing the crack to deflect and terminate multiple times during its extension process, thereby significantly improving the tear resistance of the sheath layer. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention more apparent, the invention is described in detail below. It should be understood that the invention is not limited to the description herein.

[0019] EPDM rubber The EPDM rubber used in this invention is a type of EPDM rubber known in the art for use in cables, and this invention is not limited to the specific models listed below. As an example, the Mooney viscosity (ML) of the EPDM rubber... 1+4 The temperature (125℃) can be 35~95, and the weight-average molecular weight can be 70,000~220,000. In the sheath layer of the aluminum alloy medium-voltage power cable of the present invention, EPDM rubber as the matrix material can ensure the mechanical strength and structural stability of the sheath layer. At the same time, it has excellent electrical insulation, aging resistance and high and low temperature resistance, ensuring the long-term service protection capability of the sheath layer.

[0020] Styrene-butadiene rubber The styrene-butadiene rubber used in this invention is a type of styrene-butadiene rubber known in the art for use in cables, and this invention is not limited to the specific types listed below. As an example, the Mooney viscosity (ML) of styrene-butadiene rubber... 1+4 The temperature (at 100℃) can be 40~85, and the weight-average molecular weight can be 60,000~200,000. In the sheath layer of the aluminum alloy medium-voltage power cable of the present invention, styrene-butadiene rubber can improve the flexibility and wear resistance of the sheath layer, and also has good weather resistance, further enhancing the overall performance of the cable sheath.

[0021] vulcanizing agent The vulcanizing agent used in this invention is a vulcanizing agent known in the art for use in cable rubber materials, and this invention is not limited to the specific types listed below. As an example, the vulcanizing agent can be sulfur and / or dicumyl peroxide. In the sheath layer of the aluminum alloy medium-voltage power cable of this invention, the role of the vulcanizing agent is to promote the cross-linking of rubber molecular chains, constructing a three-dimensional cross-linked network.

[0022] vulcanization accelerator The vulcanization accelerator used in this invention is a vulcanization accelerator known in the art for use in cable rubber materials, and this invention is not limited to the specific types listed below. As an example, the vulcanization accelerator can be one or more of accelerator M, accelerator DM, accelerator CZ, and accelerator TMTD. In the sheath layer of the aluminum alloy medium-voltage power cable of this invention, the role of the vulcanization accelerator is to reduce the activation energy of the vulcanization reaction, accelerate the cross-linking reaction rate of the rubber molecular chains, shorten the vulcanization cycle, and make the rubber cross-linking structure more uniform and stable.

[0023] Silane coupling agents The silane coupling agent used in this invention is a known silane coupling agent in the art that can be used in polymer composites, and this invention is not limited to the specific types listed below. As an example, the silane coupling agent can be one or more of KH-550, KH-560, KH-570, and A172. In the sheath layer of the aluminum alloy medium-voltage power cable of this invention, the role of the silane coupling agent is to improve the compatibility of the inorganic filler in the rubber matrix, making it more uniformly dispersed, thereby ensuring that the sheath layer will not have interface defects during processing.

[0024] Anti-aging agents The antioxidant used in this invention is a known antioxidant for cables, and the invention is not limited to the specific types listed below. For example, the antioxidant may be one or more of antioxidants RD, 4010NA, MB, and BLE. In the sheath layer of the aluminum alloy medium-voltage power cable of this invention, the antioxidant functions to delay the aging, cracking, hardening, and failure of the sheath material, thereby improving the aging resistance of the cable sheath layer.

[0025] Sericite The sericite used in this invention is a type of sericite known in the art for use in polymer composites, and this invention is not limited to the sericite listed below. For example, the particle size of the sericite can be 800-3000 mesh. In the sheath layer of the aluminum alloy medium-voltage power cable of this invention, sericite and sepiolite fiber-loaded magnesium-iron hydrotalcite work synergistically to further improve the tear strength of the sheath layer, thereby improving the tear resistance of the aluminum alloy medium-voltage power cable. This is because the sepiolite fiber-loaded magnesium-iron hydrotalcite, on the one hand, achieves stress transmission and dispersion through the fiber skeleton, weakening the concentration of external forces; on the other hand, the hydrotalcite sheets grown on the surface initially hinder crack propagation. The sericite, with its high aspect ratio sheet structure, can be interwoven and distributed within the rubber matrix, playing a secondary role in blocking and deflecting cracks. Thus, the two work synergistically to further improve the tear resistance of the aluminum alloy medium-voltage power cable.

[0026] A medium-voltage power cable made of aluminum alloy An aluminum alloy medium-voltage power cable comprises, from the inside out, a conductor, an insulation layer, an armor layer, and a sheath layer; The conductor is a tightly wound aluminum alloy conductor; The sheath layer comprises the following components by weight: 70-80 parts EPDM rubber, 20-30 parts styrene-butadiene rubber, 35-45 parts inorganic filler, 7-12 parts naphthenic oil, 2-2.5 parts vulcanizing agent, 2.5-3 parts vulcanization accelerator, 1.5-2 parts stearic acid, 4-5 parts zinc oxide, 0.8-1.5 parts silane coupling agent, and 1.5-3 parts antioxidant; Inorganic fillers include sepiolite fiber-supported magnesium-iron hydrotalcite.

[0027] In the sheath layer of aluminum alloy medium-voltage power cable, the weight parts of EPDM rubber are 70-80 parts, preferably 72-78 parts, more preferably 73-76 parts, and most preferably 74-75 parts.

[0028] In the sheath layer of aluminum alloy medium-voltage power cable, the weight parts of styrene-butadiene rubber are 20 to 30 parts, preferably 21 to 27 parts, more preferably 22 to 25 parts, and most preferably 23 to 25 parts.

[0029] In the sheath layer of aluminum alloy medium-voltage power cable, the inorganic filler has a weight percentage of 30-40 parts, preferably 32-40 parts, more preferably 35-40 parts, and most preferably 37-40 parts.

[0030] In the sheath layer of aluminum alloy medium-voltage power cables, the weight percentage of naphthenic oil is 7-12 parts, preferably 7-10 parts, and most preferably 8-20 parts.

[0031] In the sheath layer of aluminum alloy medium-voltage power cables, the weight of the vulcanizing agent is 2 to 2.5 parts, preferably 2.1 to 2.5 parts, and most preferably 2.2 to 2.4 parts.

[0032] In the sheath layer of aluminum alloy medium-voltage power cable, the vulcanization accelerator is 2.4 to 3 parts by weight, preferably 2.6 to 3 parts, more preferably 2.7 to 3 parts, and most preferably 2.8 to 3 parts.

[0033] In the sheath layer of aluminum alloy medium-voltage power cables, the weight percentage of stearic acid is 1.5 to 2 parts, preferably 1.5 to 1.9 parts, and most preferably 1.6 to 1.8 parts.

[0034] In the sheath layer of the aluminum alloy medium-voltage power cable, the zinc oxide content is 4 to 5 parts by weight, preferably 4.5 to 5 parts, more preferably 4.6 to 5 parts, and most preferably 4.6 to 4.8 parts.

[0035] In the sheath layer of aluminum alloy medium-voltage power cable, the weight of silane coupling agent is 0.8 to 1.5 parts, preferably 1 to 1.5 parts, more preferably 1 to 1.4 parts, and most preferably 1 to 1.2 parts.

[0036] In the sheath layer of aluminum alloy medium-voltage power cables, the antioxidant is present in 1.5 to 3 parts by weight, preferably 1.5 to 2.5 parts, more preferably 1.8 to 2.2 parts, and most preferably 2 to 2.2 parts.

[0037] In the sheath layer of aluminum alloy medium-voltage power cables, inorganic fillers also include sericite.

[0038] In the sheath layer of aluminum alloy medium-voltage power cables, the mass ratio of sepiolite fiber-loaded MgFe hydrotalcite to sericite is 2~3:1, with the optimal ratio being 2.2~3:1. If the ratio is too low, the sericite will be excessive and prone to agglomeration; if the ratio is too high, the lamellar reinforcement will be insufficient. At this mass ratio, the tear resistance of the sheath layer can reach its maximum.

[0039] Preparation method of sepiolite fiber-supported magnesium-iron hydrotalcite The present invention also provides a method for preparing sepiolite fiber-supported magnesium-iron hydrotalcite as described above, comprising: Ferric chloride hexahydrate and magnesium chloride hexahydrate were dissolved in water, sepiolite fibers were added, and then sodium hydroxide solution was added to adjust the pH to 11-12. The resulting solution system was transferred to a reactor for hydrothermal reaction, centrifugation and washing were performed to obtain a solid, which was then dried to obtain sepiolite fiber-supported magnesium-iron hydrotalcite.

[0040] Preparation method of aluminum alloy medium voltage power cable The present invention also provides a method for preparing an aluminum alloy medium-voltage power cable as described above, comprising the following steps: S1. Compactly twist aluminum alloy monofilaments together to obtain a conductor; S2. Extruding the insulating material and coating it onto the outer surface of the conductor to obtain the insulating layer; S3. Wrap the armor layer material around the outer surface of the insulation layer to obtain the armor layer; S4. The components of the sheath layer are proportioned according to their weight ratios, mixed evenly, and then subjected to intensive mixing to obtain the sheath material. The sheath material is extruded and coated onto the outer surface of the armor layer. After vulcanization, cross-linking, cooling and shaping, and traction winding, an aluminum alloy medium-voltage power cable is obtained.

[0041] To further illustrate the present invention, the following examples will provide a detailed description. The raw materials used in the following examples and comparative examples of the present invention are all commercially available products. Specifically, the EPDM rubber is EPDM 4045; the styrene-butadiene rubber is SBR-1502; the sepiolite fiber has a diameter of 0.8 μm and an aspect ratio of 20; and the sericite has an average particle size of 10 μm.

[0042] Example 1 The manufacturing methods for aluminum alloy medium-voltage power cables include: S1. Compactly twist aluminum alloy monofilaments together with a compaction factor of 0.9 to obtain a conductor; S2. Extruding cross-linked polyethylene material onto the outer surface of the conductor to obtain a cross-linked polyethylene insulation layer; S3. Wrap galvanized steel strip around the outer surface of the insulation layer to obtain the armor layer; S4. Weigh out 70 parts of EPDM rubber, 20 parts of styrene-butadiene rubber, 30 parts of sepiolite fiber-loaded magnesium iron hydrotalcite, 7 parts of naphthenic oil, 1.5 parts of stearic acid, 4 parts of zinc oxide, 0.8 parts of silane coupling agent KH-570 and 1.5 parts of antioxidant 4010NA, mix them evenly and add them to a mixer. Mix at 100℃ for 8 minutes, then cool to 70℃, add 2 parts of sulfur, 1.2 parts of accelerator CZ and 1.2 parts of accelerator DM and mix for 3 minutes to obtain the sheath material. Extrude the sheath material through an extruder to cover the outer surface of the armor layer. After vulcanization and cross-linking at 150℃, cooling and shaping, and traction winding, the aluminum alloy medium voltage power cable is obtained.

[0043] The preparation method of the above-mentioned sepiolite fiber-supported magnesium-iron hydrotalcite includes: 2g of ferric chloride hexahydrate and 6g of magnesium chloride hexahydrate were dissolved in 100mL of water. 1.4g of sepiolite fiber was added, and then a 2mol / L sodium hydroxide solution was added to adjust the pH to 11. The resulting solution system was transferred to a reaction vessel and hydrothermally reacted at 170℃ for 6h. After centrifugation and washing, the solid was obtained and dried to obtain sepiolite fiber-supported magnesium-iron hydrotalcite.

[0044] Example 2 The manufacturing methods for aluminum alloy medium-voltage power cables include: S1. Compactly twist aluminum alloy monofilaments together with a compaction coefficient of 0.92 to obtain a conductor; S2. Extruding cross-linked polyethylene material onto the outer surface of the conductor to obtain a cross-linked polyethylene insulation layer; S3. Wrap galvanized steel strip around the outer surface of the insulation layer to obtain the armor layer; S4. Weigh out 80 parts of EPDM rubber, 30 parts of styrene-butadiene rubber, 40 parts of sepiolite fiber-loaded magnesium iron hydrotalcite, 12 parts of naphthenic oil, 2 parts of stearic acid, 5 parts of zinc oxide, 1.5 parts of silane coupling agent KH-570 and 3 parts of antioxidant 4010NA, mix them evenly and add them to a mixer. Mix at 100℃ for 8 minutes, then cool to 70℃, add 2.5 parts of sulfur, 1.5 parts of accelerator CZ and 1.5 parts of accelerator DM and mix for 3 minutes to obtain the sheath material. Extrude the sheath material through an extruder to cover the outer surface of the armor layer. After vulcanization and cross-linking at 150℃, cooling and shaping, and traction winding, the aluminum alloy medium voltage power cable is obtained.

[0045] The preparation method of the above-mentioned sepiolite fiber-supported magnesium-iron hydrotalcite includes: 3g of ferric chloride hexahydrate and 6g of magnesium chloride hexahydrate were dissolved in 100mL of water. 1.7g of sepiolite fiber was added, and then a 2mol / L sodium hydroxide solution was added to adjust the pH to 12. The resulting solution system was transferred to a reaction vessel and hydrothermally reacted at 190℃ for 5h. After centrifugation and washing, the solid was obtained and dried to obtain sepiolite fiber-supported magnesium-iron hydrotalcite.

[0046] Example 3 The manufacturing methods for aluminum alloy medium-voltage power cables include: S1. Compactly twist aluminum alloy monofilaments together with a compaction coefficient of 0.92 to obtain a conductor; S2. Extruding cross-linked polyethylene material onto the outer surface of the conductor to obtain a cross-linked polyethylene insulation layer; S3. Wrap galvanized steel strip around the outer surface of the insulation layer to obtain the armor layer; S4. Weigh out 75 parts of EPDM rubber, 25 parts of styrene-butadiene rubber, 35 parts of sepiolite fiber-loaded magnesium iron hydrotalcite, 10 parts of naphthenic oil, 1.8 parts of stearic acid, 4.5 parts of zinc oxide, 1.2 parts of silane coupling agent KH-570 and 2 parts of antioxidant 4010NA, mix them evenly and add them to a mixer. Mix at 100℃ for 8 minutes, then cool to 70℃, add 2.2 parts of sulfur, 1.4 parts of accelerator CZ and 1.4 parts of accelerator DM and mix for 3 minutes to obtain the sheath material. Extrude the sheath material through an extruder to cover the outer surface of the armor layer. After vulcanization and cross-linking at 150℃, cooling and shaping, and traction winding, the aluminum alloy medium voltage power cable is obtained.

[0047] The preparation method of the above-mentioned sepiolite fiber-supported magnesium-iron hydrotalcite includes: 2.7 g of ferric chloride hexahydrate and 6 g of magnesium chloride hexahydrate were dissolved in 100 mL of water. 1.7 g of sepiolite fiber was added, and then a 2 mol / L sodium hydroxide solution was added to adjust the pH to 12. The resulting solution system was transferred to a reaction vessel and hydrothermally reacted at 180 °C for 5 h. The solid was obtained by centrifugation and washing, and then dried to obtain sepiolite fiber-supported magnesium-iron hydrotalcite.

[0048] Example 4 The manufacturing methods for aluminum alloy medium-voltage power cables include: S1. Compactly twist aluminum alloy monofilaments together with a compaction coefficient of 0.92 to obtain a conductor; S2. Extruding cross-linked polyethylene material onto the outer surface of the conductor to obtain a cross-linked polyethylene insulation layer; S3. Wrap galvanized steel strip around the outer surface of the insulation layer to obtain the armor layer; S4. Weigh out 80 parts of EPDM rubber, 30 parts of styrene-butadiene rubber, 20 parts of sepiolite fiber-loaded magnesium iron hydrotalcite, 20 parts of sericite, 12 parts of naphthenic oil, 2 parts of stearic acid, 5 parts of zinc oxide, 1.5 parts of silane coupling agent KH-570 and 3 parts of antioxidant 4010NA, mix them evenly and add them to a mixer. Mix at 100℃ for 8 minutes, then cool to 70℃, add 2.5 parts of sulfur, 1.5 parts of accelerator CZ and 1.5 parts of accelerator DM and mix for 3 minutes to obtain the sheath material. Extrude the sheath material through an extruder to cover the outer surface of the armor layer. After vulcanization and cross-linking at 150℃, cooling and shaping, and traction winding, the aluminum alloy medium voltage power cable is obtained.

[0049] The preparation method of the above-mentioned sepiolite fiber-supported magnesium-iron hydrotalcite includes: 3g of ferric chloride hexahydrate and 6g of magnesium chloride hexahydrate were dissolved in 100mL of water. 1.7g of sepiolite fiber was added, and then a 2mol / L sodium hydroxide solution was added to adjust the pH to 12. The resulting solution system was transferred to a reaction vessel and hydrothermally reacted at 190℃ for 5h. After centrifugation and washing, the solid was obtained and dried to obtain sepiolite fiber-supported magnesium-iron hydrotalcite.

[0050] Example 5 The manufacturing methods for aluminum alloy medium-voltage power cables include: S1. Compactly twist aluminum alloy monofilaments together with a compaction coefficient of 0.92 to obtain a conductor; S2. Extruding cross-linked polyethylene material onto the outer surface of the conductor to obtain a cross-linked polyethylene insulation layer; S3. Wrap galvanized steel strip around the outer surface of the insulation layer to obtain the armor layer; S4. Weigh out 80 parts of EPDM rubber, 30 parts of styrene-butadiene rubber, 27.5 parts of sepiolite fiber-loaded magnesium iron hydrotalcite, 12.5 parts of sericite, 12 parts of naphthenic oil, 2 parts of stearic acid, 5 parts of zinc oxide, 1.5 parts of silane coupling agent KH-570 and 3 parts of antioxidant 4010NA, mix them evenly and add them to a mixer. Mix at 100℃ for 8 minutes, then cool to 70℃, add 2.5 parts of sulfur, 1.5 parts of accelerator CZ and 1.5 parts of accelerator DM and mix for 3 minutes to obtain the sheath material. Extrude the sheath material through an extruder to cover the outer surface of the armor layer. After vulcanization and cross-linking at 150℃, cooling and shaping, and traction winding, the aluminum alloy medium voltage power cable is obtained.

[0051] The preparation method of the above-mentioned sepiolite fiber-supported magnesium-iron hydrotalcite includes: 3g of ferric chloride hexahydrate and 6g of magnesium chloride hexahydrate were dissolved in 100mL of water. 1.7g of sepiolite fiber was added, and then a 2mol / L sodium hydroxide solution was added to adjust the pH to 12. The resulting solution system was transferred to a reaction vessel and hydrothermally reacted at 190℃ for 5h. After centrifugation and washing, the solid was obtained and dried to obtain sepiolite fiber-supported magnesium-iron hydrotalcite.

[0052] Example 6 The manufacturing methods for aluminum alloy medium-voltage power cables include: S1. Compactly twist aluminum alloy monofilaments together with a compaction coefficient of 0.92 to obtain a conductor; S2. Extruding cross-linked polyethylene material onto the outer surface of the conductor to obtain a cross-linked polyethylene insulation layer; S3. Wrap galvanized steel strip around the outer surface of the insulation layer to obtain the armor layer; S4. Weigh out 80 parts of EPDM rubber, 30 parts of styrene-butadiene rubber, 30 parts of sepiolite fiber-loaded magnesium iron hydrotalcite, 10 parts of sericite, 12 parts of naphthenic oil, 2 parts of stearic acid, 5 parts of zinc oxide, 1.5 parts of silane coupling agent KH-570 and 3 parts of antioxidant 4010NA, mix them evenly and add them to a mixer. Mix at 100℃ for 8 minutes, then cool to 70℃, add 2.5 parts of sulfur, 1.5 parts of accelerator CZ and 1.5 parts of accelerator DM and mix for 3 minutes to obtain the sheath material. Extrude the sheath material through an extruder to cover the outer surface of the armor layer. After vulcanization and cross-linking at 150℃, cooling and shaping, and traction winding, the aluminum alloy medium voltage power cable is obtained.

[0053] The preparation method of the above-mentioned sepiolite fiber-supported magnesium-iron hydrotalcite includes: 3g of ferric chloride hexahydrate and 6g of magnesium chloride hexahydrate were dissolved in 100mL of water. 1.7g of sepiolite fiber was added, and then a 2mol / L sodium hydroxide solution was added to adjust the pH to 12. The resulting solution system was transferred to a reaction vessel and hydrothermally reacted at 190℃ for 5h. After centrifugation and washing, the solid was obtained and dried to obtain sepiolite fiber-supported magnesium-iron hydrotalcite.

[0054] Example 7 The manufacturing methods for aluminum alloy medium-voltage power cables include: S1. Compactly twist aluminum alloy monofilaments together with a compaction coefficient of 0.92 to obtain a conductor; S2. Extruding cross-linked polyethylene material onto the outer surface of the conductor to obtain a cross-linked polyethylene insulation layer; S3. Wrap galvanized steel strip around the outer surface of the insulation layer to obtain the armor layer; S4. Weigh out 80 parts of EPDM rubber, 30 parts of styrene-butadiene rubber, 32 parts of sepiolite fiber-loaded magnesium iron hydrotalcite, 8 parts of sericite, 12 parts of naphthenic oil, 2 parts of stearic acid, 5 parts of zinc oxide, 1.5 parts of silane coupling agent KH-570 and 3 parts of antioxidant 4010NA, mix them evenly and add them to a mixer. Mix at 100℃ for 8 minutes, then cool to 70℃, add 2.5 parts of sulfur, 1.5 parts of accelerator CZ and 1.5 parts of accelerator DM and mix for 3 minutes to obtain the sheath material. Extrude the sheath material through an extruder to cover the outer surface of the armor layer. After vulcanization and cross-linking at 150℃, cooling and shaping, and traction winding, the aluminum alloy medium voltage power cable is obtained.

[0055] The preparation method of the above-mentioned sepiolite fiber-supported magnesium-iron hydrotalcite includes: 3g of ferric chloride hexahydrate and 6g of magnesium chloride hexahydrate were dissolved in 100mL of water. 1.7g of sepiolite fiber was added, and then a 2mol / L sodium hydroxide solution was added to adjust the pH to 12. The resulting solution system was transferred to a reaction vessel and hydrothermally reacted at 190℃ for 5h. After centrifugation and washing, the solid was obtained and dried to obtain sepiolite fiber-supported magnesium-iron hydrotalcite.

[0056] Comparative Example 1 The manufacturing methods for aluminum alloy medium-voltage power cables include: S1. Compactly twist aluminum alloy monofilaments together with a compaction coefficient of 0.92 to obtain a conductor; S2. Extruding cross-linked polyethylene material onto the outer surface of the conductor to obtain a cross-linked polyethylene insulation layer; S3. Wrap galvanized steel strip around the outer surface of the insulation layer to obtain the armor layer; S4. Weigh out 80 parts of EPDM rubber, 30 parts of styrene-butadiene rubber, 40 parts of sepiolite fiber-loaded magnesium aluminum hydrotalcite, 12 parts of naphthenic oil, 2 parts of stearic acid, 5 parts of zinc oxide, 1.5 parts of silane coupling agent KH-570 and 3 parts of antioxidant 4010NA, mix them evenly and add them to a mixer. Mix at 100℃ for 8 minutes, then cool to 70℃, add 2.5 parts of sulfur, 1.5 parts of accelerator CZ and 1.5 parts of accelerator DM and mix for 3 minutes to obtain the sheath material. Extrude the sheath material through an extruder to cover the outer surface of the armor layer. After vulcanization and cross-linking at 150℃, cooling and shaping, and traction winding, the aluminum alloy medium voltage power cable is obtained.

[0057] The preparation method of the above-mentioned sepiolite fiber-supported magnesium aluminum hydrotalcite includes: 3g of aluminum chloride hexahydrate and 6g of magnesium chloride hexahydrate were dissolved in 100mL of water. 1.7g of sepiolite fiber was added, and then sodium hydroxide solution with a concentration of 2mol / L was added to adjust the pH to 11.5. The resulting solution system was transferred to a reaction vessel and hydrothermally reacted at 190℃ for 5h. After centrifugation and washing, the solid was obtained and dried to obtain sepiolite fiber-supported magnesium aluminum hydrotalcite.

[0058] Comparative Example 2 The manufacturing methods for aluminum alloy medium-voltage power cables include: S1. Compactly twist aluminum alloy monofilaments together with a compaction coefficient of 0.92 to obtain a conductor; S2. Extruding cross-linked polyethylene material onto the outer surface of the conductor to obtain a cross-linked polyethylene insulation layer; S3. Wrap galvanized steel strip around the outer surface of the insulation layer to obtain the armor layer; S4. Weigh out 80 parts of EPDM rubber, 30 parts of styrene-butadiene rubber, 40 parts of sepiolite fiber, 12 parts of naphthenic oil, 2 parts of stearic acid, 5 parts of zinc oxide, 1.5 parts of silane coupling agent KH-570 and 3 parts of antioxidant 4010NA, mix them evenly, and add them to a mixer. Mix at 100℃ for 8 minutes, then cool down to 70℃, add 2.5 parts of sulfur, 1.5 parts of accelerator CZ and 1.5 parts of accelerator DM and mix for 3 minutes to obtain the sheath material. Extrude the sheath material through an extruder to cover the outer surface of the armor layer. After vulcanization and cross-linking at 150℃, cooling and shaping, and traction winding, the aluminum alloy medium voltage power cable is obtained.

[0059] Comparative Example 3 The manufacturing methods for aluminum alloy medium-voltage power cables include: S1. Compactly twist aluminum alloy monofilaments together with a compaction coefficient of 0.92 to obtain a conductor; S2. Extruding cross-linked polyethylene material onto the outer surface of the conductor to obtain a cross-linked polyethylene insulation layer; S3. Wrap galvanized steel strip around the outer surface of the insulation layer to obtain the armor layer; S4. Weigh out 80 parts of EPDM rubber, 30 parts of styrene-butadiene rubber, 40 parts of magnesium-iron hydrotalcite, 12 parts of naphthenic oil, 2 parts of stearic acid, 5 parts of zinc oxide, 1.5 parts of silane coupling agent KH-570 and 3 parts of antioxidant 4010NA, mix them evenly and add them to a mixer. Mix at 100℃ for 8 minutes, then cool down to 70℃, add 2.5 parts of sulfur, 1.5 parts of accelerator CZ and 1.5 parts of accelerator DM and mix for 3 minutes to obtain the sheath material. Extrude the sheath material through an extruder to cover the outer surface of the armor layer. After vulcanization and cross-linking at 150℃, cooling and shaping, and traction winding, the aluminum alloy medium voltage power cable is obtained.

[0060] Comparative Example 4 The manufacturing methods for aluminum alloy medium-voltage power cables include: S1. Compactly twist aluminum alloy monofilaments together with a compaction coefficient of 0.92 to obtain a conductor; S2. Extruding cross-linked polyethylene material onto the outer surface of the conductor to obtain a cross-linked polyethylene insulation layer; S3. Wrap galvanized steel strip around the outer surface of the insulation layer to obtain the armor layer; S4. Weigh out 80 parts of EPDM rubber, 30 parts of styrene-butadiene rubber, 40 parts of sericite, 12 parts of naphthenic oil, 2 parts of stearic acid, 5 parts of zinc oxide, 1.5 parts of silane coupling agent KH-570 and 3 parts of antioxidant 4010NA, mix them evenly, and add them to a mixer. Mix at 100℃ for 8 minutes, then cool to 70℃, add 2.5 parts of sulfur, 1.5 parts of accelerator CZ and 1.5 parts of accelerator DM and mix for 3 minutes to obtain the sheath material. Extrude the sheath material through an extruder to cover the outer surface of the armor layer. After vulcanization and cross-linking at 150℃, cooling and shaping, and traction winding, the aluminum alloy medium voltage power cable is obtained.

[0061] Performance testing The tear strength of the sheath layer was determined according to GB / T 529-2008 "Determination of tear strength of vulcanized rubber or thermoplastic rubber (trouser-shaped, right-angled and crescent-shaped specimens)" and the specimens were right-angled specimens. The performance of each embodiment and comparative example after testing is shown in Table 1.

[0062] Table 1. Test results of Examples 1-7 and Comparative Examples 1-4

[0063] By comparing the data of Examples 1-3 and Comparative Examples 1-4, the tear strength of the sheath layer obtained by adding sepiolite fiber loaded with magnesium iron hydrotalcite in Examples 1-3 is greater than that in Comparative Examples 1-4. This shows that by adding sepiolite fiber loaded with magnesium iron hydrotalcite, the tear resistance of the sheath layer can be improved, thereby improving the tear resistance of aluminum alloy medium voltage power cables.

[0064] By comparing the data from Examples 2, 4-7, and Comparative Example 4, it was found that Examples 4-7, by adding sepiolite fiber-loaded MgFe hydrotalcite and sericite composites, achieved a greater tear strength in the sheath layer than Examples 2 and Comparative Example 4. This indicates that the combination of sepiolite fiber-loaded MgFe hydrotalcite and sericite improves the tear resistance of the sheath layer, thereby enhancing the tear resistance of the aluminum alloy medium-voltage power cable. Furthermore, by comparing the data from Examples 4-7, Examples 5-6, by controlling the amount of sepiolite fiber-loaded MgFe hydrotalcite and sericite added, further improved the tear resistance of the aluminum alloy medium-voltage power cable when the mass ratio of sepiolite fiber-loaded MgFe hydrotalcite to sericite was 2.2-3:1.

[0065] 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. An aluminum alloy medium-voltage power cable, characterized in that, From the inside out, it includes the conductor, insulation layer, armor layer, and sheath layer; The conductor is a tightly pressed stranded aluminum alloy conductor; The sheath layer comprises the following components by weight: 70-80 parts of EPDM rubber, 20-30 parts of styrene-butadiene rubber, 30-40 parts of inorganic filler, 7-12 parts of naphthenic oil, 2-2.5 parts of vulcanizing agent, 2.4-3 parts of vulcanization accelerator, 1.5-2 parts of stearic acid, 4-5 parts of zinc oxide, 0.8-1.5 parts of silane coupling agent, and 1.5-3 parts of antioxidant; The inorganic filler includes sepiolite fiber-loaded magnesium-iron hydrotalcite.

2. The aluminum alloy medium-voltage power cable according to claim 1, characterized in that, In the aluminum alloy tightly packed stranded conductor, the compaction coefficient is 0.9~0.

92.

3. The aluminum alloy medium-voltage power cable according to claim 1, characterized in that, The armor layer is made of galvanized steel strip.

4. The aluminum alloy medium-voltage power cable according to claim 1, characterized in that, The preparation method of the sepiolite fiber-supported magnesium-iron hydrotalcite includes the following steps: Ferric chloride hexahydrate and magnesium chloride hexahydrate were dissolved in water, sepiolite fibers were added, and then sodium hydroxide solution was added to adjust the pH to 11-12. The resulting solution system was transferred to a reactor for hydrothermal reaction, centrifugation and washing were performed to obtain a solid, which was then dried to obtain the sepiolite fiber-supported magnesium-iron hydrotalcite.

5. The aluminum alloy medium-voltage power cable according to claim 4, characterized in that, The mass ratio of ferric chloride hexahydrate to magnesium chloride hexahydrate is 2~3:6; The mass ratio of magnesium chloride hexahydrate to sepiolite fiber is 6:1.4~1.7; The hydrothermal reaction temperature is 170~190℃, and the hydrothermal reaction time is 4~5h.

6. The aluminum alloy medium-voltage power cable according to claim 1, characterized in that, The inorganic packing also includes lamellar inorganic packing.

7. The aluminum alloy medium-voltage power cable according to claim 6, characterized in that, The mass ratio of the sepiolite fiber-loaded magnesium-iron hydrotalcite to the lamellar inorganic filler is 2.2~3:

1.

8. The aluminum alloy medium-voltage power cable according to claim 7, characterized in that, The lamellar inorganic filler includes one or more of hydrotalcite, montmorillonite, talc powder, and sericite; Preferably, the lamellar inorganic filler is sericite.

9. The aluminum alloy medium-voltage power cable according to claim 1, characterized in that, The vulcanizing agent includes sulfur; The vulcanization accelerator includes one or more of accelerator M, accelerator DM, accelerator CZ, and accelerator TMTD.

10. A method for preparing an aluminum alloy medium-voltage power cable, used to prepare the aluminum alloy medium-voltage power cable according to any one of claims 1 to 9, characterized in that, Includes the following steps: S1. Compactly twist aluminum alloy monofilaments together to obtain a conductor; S2. Extruding the insulating material and coating it onto the outer surface of the conductor to obtain the insulating layer; S3. Wrap the armor layer material around the outer surface of the insulation layer to obtain the armor layer; S4. The components of the sheath layer are proportioned according to the weight ratio, mixed evenly, and then subjected to intensive mixing to obtain the sheath material. The sheath material is extruded and coated onto the outer surface of the armor layer. After vulcanization, cross-linking, cooling and shaping, and traction winding, the aluminum alloy medium-voltage power cable is obtained.

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