Cold-resistant high-voltage cable and preparation method thereof
By using specific component compounding and segmented extrusion processes to prepare cold-resistant high-pressure outer sheaths, the problem of high-density polyethylene and cross-linked polyethylene becoming brittle under low temperature and high pressure is solved, achieving high-pressure stability and low-temperature toughness of cables in extreme cold environments such as polar regions.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHANGHAI ZHAOSHUO SPECIAL CABLE CO LTD
- Filing Date
- 2025-12-31
- Publication Date
- 2026-07-28
AI Technical Summary
Under low temperature and high pressure conditions, the molecular chain segment mobility of semi-crystalline polymers such as high-density polyethylene and cross-linked polyethylene decreases, the material toughness decreases, and it is prone to embrittlement and cracking, affecting the stability of cable use.
A cold-resistant high-pressure outer sheath is prepared by compounding specific components such as maleic anhydride-grafted POE, hydrogenated styrene-butadiene-styrene block copolymer and high-pressure modified fiber, and by segmented extrusion process. The high-pressure modified fiber is formed by combining pre-modified basalt fiber, 4-(N-maleimide)benzophenone and pyromellitic diimide, which inhibits space charge accumulation and improves low-temperature toughness and high-pressure stability.
Under high pressure and low temperature conditions, the stability and mechanical properties of the cable are significantly improved, suppressing embrittlement and cracking, and ensuring the high pressure stability and low temperature toughness of the cable.
Smart Images
Figure SMS_1 
Figure SMS_2
Abstract
Description
Technical Field
[0001] This invention relates to the field of polyolefin cable technology, specifically a cold-resistant high-voltage cable and its preparation method. Background Technology
[0002] Cables, as core components for electrical power transmission, are widely used in power, communications, transportation, and other fields. Cables are mainly composed of conductors and insulation materials, among which the insulation materials directly affect the reliability and safety of the cable.
[0003] High-density polyethylene and cross-linked polyethylene have excellent insulation properties and are widely used in cable insulation materials. With the development of cables, people are gradually turning their attention to extremely cold regions such as polar regions, sea areas, and winters, requiring not only excellent insulation but also stability under high pressure and extreme cold conditions.
[0004] However, in practical use, it has been found that under low temperature and high pressure conditions, the molecular chain segment activity of semi-crystalline polymers such as high-density polyethylene and cross-linked polyethylene decreases, the material toughness decreases, and it is prone to embrittlement and cracking, which seriously affects the use of cables.
[0005] In summary, the development of a cold-resistant high-voltage cable and its preparation method is of great significance in addressing the aforementioned issues. Summary of the Invention
[0006] The purpose of this invention is to provide a cold-resistant high-voltage cable and its preparation method to solve the problems mentioned in the background art.
[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution: A method for preparing a cold-resistant high-voltage cable includes the following steps: Step 1: Mix high-density polyethylene, linear low-density polyethylene, maleic anhydride-grafted POE, hydrogenated styrene-butadiene-styrene block copolymer, crosslinking agent, antioxidant, and lubricant evenly and stir at high temperature to obtain a premix. Step 2: The premixed material is melt-extruded. The melt extrusion process includes 6 temperature zones. High-pressure modified fibers are added in the fourth temperature zone, and the material is cooled and molded to obtain a cold-resistant high-pressure outer sheath. Step 3: Wrap the cable core with the outer sheath, shielding layer, and insulation layer in sequence to obtain a cold-resistant high-voltage cable.
[0008] In a more optimized manner, the raw materials of the premix include the following components by weight: 45-55 parts high-density polyethylene, 15-25 parts linear low-density polyethylene, 6-12 parts maleic anhydride-grafted POE, 3-7 parts hydrogenated styrene-butadiene-styrene block copolymer, 1.2-2.5 parts crosslinking agent, 0.2-0.8 parts antioxidant, and 0.1-0.6 parts lubricant; The mass ratio of the premix to the high-pressure modified fiber is 88:(5~8).
[0009] In a more optimized manner, the high-pressure modified fiber is composed of pre-modified basalt fiber, 4-(N-maleimide)benzophenone, and pyromellitic diimide.
[0010] In a more optimized manner, the high-pressure modified fiber comprises pre-modified basalt fiber, 4-(N-maleimide)benzophenone, and pyromellitic diimide in a mass ratio of (5~7):(1.2~2):(0.5~1).
[0011] In a more optimized manner, the six temperature zones in the melt extrusion are as follows: the first temperature zone is 140~150℃; the second temperature zone is 150~160℃; the third temperature zone is 160~170℃; the fourth temperature zone is 175~185℃; the fifth temperature zone is 160~170℃; and the sixth temperature zone is 155~160℃.
[0012] A more optimized method for preparing the pre-modified basalt fiber is as follows: Step 1: Mix basalt fiber with hydrochloric acid, place at room temperature for 2-3 hours, wash and dry to obtain acid-etched basalt fiber; Step 2: Add acid-etched basalt fibers and aminosilane coupling agent to an ethanol aqueous solution and react at 60~70℃ for 3~5h to obtain amino-treated basalt fibers; Step 3: Add amino-modified basalt fiber, 4-(N-maleimide)benzophenone, 11-maleimide undecanoate, and triethylamine to DMF, react at 60-80℃ for 6-8 hours, purify and dry to obtain pre-modified basalt fiber.
[0013] Ideally, the length of the basalt fiber is 1~3mm; In the aminated basalt fiber, the mass ratio of acid-etched basalt fiber to aminosilane coupling agent is 1:(0.3~0.5); The raw materials for the pre-modified basalt fiber include 5-7 parts of aminated basalt fiber, 2-3 parts of 4-(N-maleimide)benzophenone, 3-4 parts of 11-maleimide undecanoate, and 0.05-0.1 parts of triethylamine.
[0014] More preferably, the crosslinking agent is dicumyl peroxide; the antioxidant includes one or more of antioxidant 168, antioxidant 1076, and antioxidant 1010; and the lubricant includes one or more of zinc stearate, calcium stearate, and ethylene bis-stearamide.
[0015] Ideally, the grafting rate of the maleic anhydride-grafted POE is 0.6% to 1.0%; and the density of the high-density polyethylene is 0.940 to 0.976 g / cm³. 3 The crystallinity is 80-90%; the density of the linear low-density polyethylene is 0.911-0.920 g / cm³. 3 .
[0016] Compared with the prior art, the beneficial effects achieved by the present invention are: This application utilizes specific components such as maleic anhydride-grafted POE, hydrogenated styrene-butadiene-styrene block copolymer, and high-pressure modified fibers as raw materials, and through specific compounding and combined with segmented extrusion process, to prepare a cold-resistant high-pressure outer sheath, which is then used to manufacture cold-resistant high-pressure cables. This improves low-temperature toughness and high-pressure stability, enabling the product to maintain high stability under high-pressure and low-temperature environments and inhibiting embrittlement and cracking.
[0017] In this process, the hydrogenated ethylene-butene soft segment in the hydrogenated styrene-butadiene-styrene block copolymer provides low-temperature resistance, while maleic anhydride-grafted POE acts as a compatibilizer to improve the compatibility and dispersion of the components in the premix.
[0018] However, although the addition of components such as hydrogenated styrene-butadiene-styrene block copolymer can improve low-temperature resistance and compatibility, space charge easily accumulates inside the insulating material under high voltage, causing electrical treeing degradation. At low temperatures, there will still be a problem of decreased mechanical properties.
[0019] Therefore, in order to solve the problems of high-pressure stability and low-temperature mechanical properties, this application further introduces high-pressure modified fibers composed of specific amounts and components to reduce space charge accumulation and inhibit electrical tree deterioration, thereby further improving the low-temperature toughness and high-pressure stability of the product.
[0020] The scheme uses pre-modified basalt fiber, 4-(N-maleimide)benzophenone, and pyromellitic diimide as raw materials to form high-pressure modified fiber in a specific ratio.
[0021] Among them, the pre-modified basalt fiber forms amide bonds through the reaction of amino and maleimide, and grafts benzophenone and undecanoate groups; its flexible long aliphatic chains form a specific synergistic effect with the hydrogenated ethylene-butene soft segments, further improving low-temperature toughness and preventing stress cracking at low temperatures; the benzophenone group, as an electron-absorbing group, can suppress space charge accumulation by absorbing electron energy when charge accumulates at the interface under high pressure and generates an excited state, ensuring the mechanical properties of the product under high pressure. 4-(N-maleimide)benzophenone can suppress the excited state during initiation; pyromellitic dicimide can suppress space charge accumulation during the electrical tree growth stage.
[0022] It is important to note that the high-pressure modified fiber must be added in the fourth temperature zone (175~185℃). This is because, in this zone, most of the components in the premix are melted. Adding the high-pressure modified fiber at this point allows the thermally unstable 4-(N-maleimide)benzophenone to disperse in a highly active state within the components, protecting its activity and further ensuring stability. This ensures the mechanical properties of the product under high pressure and low temperature. Simultaneously, adding the pre-modified basalt fiber in the fourth temperature zone, when most of the components in the premix are melted, results in greater viscous shear force, improving fiber dispersion and promoting uniform fiber distribution. If the high-pressure modified fiber is added in the first temperature zone, the premix has not yet melted, and the insufficient shear temperature leads to the inactivation of active groups. Furthermore, the premature introduction of the fiber results in extremely poor dispersion, causing agglomeration problems. This not only fails to provide any benefit but also significantly reduces low-temperature toughness and high-pressure stability. Detailed Implementation
[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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 skilled in the art without creative effort are within the scope of protection of the present invention.
[0024] It should be noted that the following quantities are by weight. There are no special restrictions on the manufacturers of the raw materials involved in this invention. Exemplary examples include: high-density polyethylene (HDPE) grade VL4580; linear low-density polyethylene (LDPE) product number DOWLEX; maleic anhydride-grafted POE grade TRD-300P; hydrogenated styrene-butadiene-styrene block copolymer product number SEBS YH-602T; basalt fiber length 3mm; antioxidant 168 (CAS number 31570-04-4); lubricant zinc stearate; 11-maleimide undecanoate (CAS number 87981-04-2); and other raw materials are commercially available.
[0025] Example 1: A method for preparing a cold-resistant high-voltage cable, comprising the following steps: Step 1: Mix 50 parts high-density polyethylene, 18 parts linear low-density polyethylene, 10 parts maleic anhydride-grafted POE, 5 parts hydrogenated styrene-butadiene-styrene block copolymer, 1.8 parts crosslinking agent (dicumyl peroxide), 0.5 parts antioxidant (antioxidant 168), and 0.4 parts lubricant (zinc stearate) evenly, and stir at 100°C for 30 minutes to obtain a premix. Step 2: The premix is melt-extruded, and the melt extrusion process includes 6 temperature zones (the first temperature zone is 145℃, the second temperature zone is 155℃; the third temperature zone is 165℃; the fourth temperature zone is 180℃; the fifth temperature zone is 165℃; and the sixth temperature zone is 158℃). High-pressure modified fibers are added in the fourth temperature zone (the mass ratio of premix to high-pressure modified fibers is 88:5), and the mixture is cooled and molded to obtain a cold-resistant high-pressure outer sheath. Step 3: Wrap the cable core with the outer sheath, shielding layer, and insulation layer in sequence to obtain a cold-resistant high-voltage cable; The high-pressure modified fiber includes pre-modified basalt fiber, 4-(N-maleimide)benzophenone, and pyromellitic diimide in a mass ratio of 5:1.2:0.5; The preparation method of pre-modified basalt fiber is as follows: Step 1: Mix basalt fiber (3 mm in length) with 3.6 wt% hydrochloric acid (mass ratio of basalt fiber to 3.6 wt% hydrochloric acid is 1:20), place at room temperature for 2.5 h, wash and dry to obtain acid-etched basalt fiber; Step 2: Add acid-etched basalt fibers and aminosilane coupling agent (KH-550) to a 70wt% ethanol aqueous solution (the mass ratio of acid-etched basalt fibers to aminosilane coupling agent is 1:0.4), and react at 65℃ for 4h to obtain amino-treated basalt fibers. Step 3: Add 6 parts of aminated basalt fiber, 2.5 parts of 4-(N-maleimide)benzophenone, 3.5 parts of 11-maleimide undecanoate, and 0.08 parts of triethylamine to DMF, react at 70°C for 7 hours, purify and dry to obtain pre-modified basalt fiber.
[0026] Example 2: A method for preparing a cold-resistant high-voltage cable, comprising the following steps: Step 1: Mix 50 parts high-density polyethylene, 18 parts linear low-density polyethylene, 10 parts maleic anhydride-grafted POE, 5 parts hydrogenated styrene-butadiene-styrene block copolymer, 1.8 parts crosslinking agent (dicumyl peroxide), 0.5 parts antioxidant (antioxidant 168), and 0.4 parts lubricant (zinc stearate) evenly, and stir at 100°C for 30 minutes to obtain a premix. Step 2: The premix is melt-extruded, and the melt extrusion process includes 6 temperature zones (the first temperature zone is 145℃, the second temperature zone is 155℃; the third temperature zone is 165℃; the fourth temperature zone is 180℃; the fifth temperature zone is 165℃; and the sixth temperature zone is 158℃). High-pressure modified fibers are added in the fourth temperature zone (the mass ratio of premix to high-pressure modified fibers is 88:7), and the mixture is cooled and molded to obtain a cold-resistant high-pressure outer sheath. Step 3: Wrap the cable core with the outer sheath, shielding layer, and insulation layer in sequence to obtain a cold-resistant high-voltage cable; The high-pressure modified fiber includes pre-modified basalt fiber, 4-(N-maleimide)benzophenone, and pyromellitic diimide in a mass ratio of 6:1.6:0.8; The preparation method of pre-modified basalt fiber is as follows: Step 1: Mix basalt fiber (3 mm in length) with 3.6 wt% hydrochloric acid (mass ratio of basalt fiber to 3.6 wt% hydrochloric acid is 1:20), place at room temperature for 2.5 h, wash and dry to obtain acid-etched basalt fiber; Step 2: Add acid-etched basalt fibers and aminosilane coupling agent (KH-550) to a 70wt% ethanol aqueous solution (the mass ratio of acid-etched basalt fibers to aminosilane coupling agent is 1:0.4), and react at 65℃ for 4h to obtain amino-treated basalt fibers. Step 3: Add 6 parts of aminated basalt fiber, 2.5 parts of 4-(N-maleimide)benzophenone, 3.5 parts of 11-maleimide undecanoate, and 0.08 parts of triethylamine to DMF, react at 70°C for 7 hours, purify and dry to obtain pre-modified basalt fiber.
[0027] Example 3: A method for preparing a cold-resistant high-voltage cable, comprising the following steps: Step 1: Mix 50 parts high-density polyethylene, 18 parts linear low-density polyethylene, 10 parts maleic anhydride-grafted POE, 5 parts hydrogenated styrene-butadiene-styrene block copolymer, 1.8 parts crosslinking agent (dicumyl peroxide), 0.5 parts antioxidant (antioxidant 168), and 0.4 parts lubricant (zinc stearate) evenly, and stir at 100°C for 30 minutes to obtain a premix. Step 2: The premix is melt-extruded, and the melt extrusion process includes 6 temperature zones (the first temperature zone is 145℃, the second temperature zone is 155℃; the third temperature zone is 165℃; the fourth temperature zone is 180℃; the fifth temperature zone is 165℃; and the sixth temperature zone is 158℃). High-pressure modified fibers are added in the fourth temperature zone (the mass ratio of premix to high-pressure modified fibers is 88:8), and the mixture is cooled and molded to obtain a cold-resistant high-pressure outer sheath. Step 3: Wrap the cable core with the outer sheath, shielding layer, and insulation layer in sequence to obtain a cold-resistant high-voltage cable; The high-pressure modified fiber includes pre-modified basalt fiber, 4-(N-maleimide)benzophenone, and pyromellitic diimide in a mass ratio of 7:2:1. The preparation method of pre-modified basalt fiber is as follows: Step 1: Mix basalt fiber (3 mm in length) with 3.6 wt% hydrochloric acid (mass ratio of basalt fiber to 3.6 wt% hydrochloric acid is 1:20), place at room temperature for 2.5 h, wash and dry to obtain acid-etched basalt fiber; Step 2: Add acid-etched basalt fibers and aminosilane coupling agent (KH-550) to a 70wt% ethanol aqueous solution (the mass ratio of acid-etched basalt fibers to aminosilane coupling agent is 1:0.4), and react at 65℃ for 4h to obtain amino-treated basalt fibers. Step 3: Add 6 parts of aminated basalt fiber, 2.5 parts of 4-(N-maleimide)benzophenone, 3.5 parts of 11-maleimide undecanoate, and 0.08 parts of triethylamine to DMF, react at 70°C for 7 hours, purify and dry to obtain pre-modified basalt fiber.
[0028] Comparative Example 1: High-pressure modified fibers were added to the first temperature zone; the rest was the same as in Example 2; the specific differences are as follows: Step 1: Mix 50 parts high-density polyethylene, 18 parts linear low-density polyethylene, 10 parts maleic anhydride-grafted POE, 5 parts hydrogenated styrene-butadiene-styrene block copolymer, 1.8 parts crosslinking agent (dicumyl peroxide), 0.5 parts antioxidant (antioxidant 168), and 0.4 parts lubricant (zinc stearate) evenly, and stir at 100°C for 30 minutes to obtain a premix. Step 2: The premix is melt-extruded, and the melt extrusion process includes 6 temperature zones (the first temperature zone is 145℃, the second temperature zone is 155℃, the third temperature zone is 165℃, the fourth temperature zone is 180℃, the fifth temperature zone is 165℃, and the sixth temperature zone is 158℃). High-pressure modified fibers are added in the first temperature zone (the mass ratio of premix to high-pressure modified fibers is 88:7), and the mixture is cooled and molded to obtain a cold-resistant high-pressure outer sheath. Step 3: Wrap the cable core with the outer sheath, shielding layer, and insulation layer in sequence to obtain a cold-resistant high-voltage cable; The high-pressure modified fiber includes pre-modified basalt fiber, 4-(N-maleimide)benzophenone, and pyromellitic diimide in a mass ratio of 6:1.6:0.8; The preparation method of pre-modified basalt fiber is as follows: Step 1: Mix basalt fiber (3 mm in length) with 3.6 wt% hydrochloric acid (mass ratio of basalt fiber to 3.6 wt% hydrochloric acid is 1:20), place at room temperature for 2.5 h, wash and dry to obtain acid-etched basalt fiber; Step 2: Add acid-etched basalt fibers and aminosilane coupling agent (KH-550) to a 70wt% ethanol aqueous solution (the mass ratio of acid-etched basalt fibers to aminosilane coupling agent is 1:0.4), and react at 65℃ for 4h to obtain amino-treated basalt fibers. Step 3: Add 6 parts of aminated basalt fiber, 2.5 parts of 4-(N-maleimide)benzophenone, 3.5 parts of 11-maleimide undecanoate, and 0.08 parts of triethylamine to DMF, react at 70°C for 7 hours, purify and dry to obtain pre-modified basalt fiber.
[0029] Comparative Example 2: No high-pressure modified fibers were added; otherwise, it was the same as Example 2; the specific differences are as follows: Step 1: Mix 50 parts high-density polyethylene, 18 parts linear low-density polyethylene, 10 parts maleic anhydride-grafted POE, 5 parts hydrogenated styrene-butadiene-styrene block copolymer, 1.8 parts crosslinking agent (dicumyl peroxide), 0.5 parts antioxidant (antioxidant 168), and 0.4 parts lubricant (zinc stearate) evenly, and stir at 100°C for 30 minutes to obtain a premix. Step 2: The premixed material is melt-extruded. The melt extrusion process includes 6 temperature zones (the first temperature zone is 145℃, the second temperature zone is 155℃, the third temperature zone is 165℃, the fourth temperature zone is 180℃, the fifth temperature zone is 165℃, and the sixth temperature zone is 158℃). After cooling and molding, a cold-resistant high-pressure outer sheath is obtained. Step 3: Wrap the cable core with the outer sheath, shielding layer, and insulation layer in sequence to obtain a cold-resistant high-voltage cable.
[0030] Comparative Example 3: No hydrogenated styrene-butadiene-styrene block copolymer added; otherwise the same as Example 2; specific differences are as follows: Step 1: Mix 50 parts of high-density polyethylene, 18 parts of linear low-density polyethylene, 10 parts of maleic anhydride-grafted POE, 1.8 parts of crosslinking agent (dicumyl peroxide), 0.5 parts of antioxidant (antioxidant 168), and 0.4 parts of lubricant (zinc stearate) evenly, and stir at 100°C for 30 minutes to obtain a premix. Step 2: The premix is melt-extruded, and the melt extrusion process includes 6 temperature zones (the first temperature zone is 145℃, the second temperature zone is 155℃; the third temperature zone is 165℃; the fourth temperature zone is 180℃; the fifth temperature zone is 165℃; and the sixth temperature zone is 158℃). High-pressure modified fibers are added in the fourth temperature zone (the mass ratio of premix to high-pressure modified fibers is 88:7), and the mixture is cooled and molded to obtain a cold-resistant high-pressure outer sheath. Step 3: Wrap the cable core with the outer sheath, shielding layer, and insulation layer in sequence to obtain a cold-resistant high-voltage cable; The high-pressure modified fiber includes pre-modified basalt fiber, 4-(N-maleimide)benzophenone, and pyromellitic diimide in a mass ratio of 6:1.6:0.8; The preparation method of pre-modified basalt fiber is as follows: Step 1: Mix basalt fiber (3 mm in length) with 3.6 wt% hydrochloric acid (mass ratio of basalt fiber to 3.6 wt% hydrochloric acid is 1:20), place at room temperature for 2.5 h, wash and dry to obtain acid-etched basalt fiber; Step 2: Add acid-etched basalt fibers and aminosilane coupling agent (KH-550) to a 70wt% ethanol aqueous solution (the mass ratio of acid-etched basalt fibers to aminosilane coupling agent is 1:0.4), and react at 65℃ for 4h to obtain amino-treated basalt fibers. Step 3: Add 6 parts of aminated basalt fiber, 2.5 parts of 4-(N-maleimide)benzophenone, 3.5 parts of 11-maleimide undecanoate, and 0.08 parts of triethylamine to DMF, react at 70°C for 7 hours, purify and dry to obtain pre-modified basalt fiber.
[0031] Comparative Example 4: The pre-modified basalt fiber was replaced with basalt fiber; the rest was the same as in Example 2; the specific differences are as follows: Step 1: Mix 50 parts high-density polyethylene, 18 parts linear low-density polyethylene, 10 parts maleic anhydride-grafted POE, 5 parts hydrogenated styrene-butadiene-styrene block copolymer, 1.8 parts crosslinking agent (dicumyl peroxide), 0.5 parts antioxidant (antioxidant 168), and 0.4 parts lubricant (zinc stearate) evenly, and stir at 100°C for 30 minutes to obtain a premix. Step 2: The premix is melt-extruded, and the melt extrusion process includes 6 temperature zones (the first temperature zone is 145℃, the second temperature zone is 155℃; the third temperature zone is 165℃; the fourth temperature zone is 180℃; the fifth temperature zone is 165℃; and the sixth temperature zone is 158℃). High-pressure modified fibers are added in the fourth temperature zone (the mass ratio of premix to high-pressure modified fibers is 88:7), and the mixture is cooled and molded to obtain a cold-resistant high-pressure outer sheath. Step 3: Wrap the cable core with the outer sheath, shielding layer, and insulation layer in sequence to obtain a cold-resistant high-voltage cable; The high-pressure modified fiber includes basalt fiber, 4-(N-maleimide)benzophenone, and pyromellitic diimide in a mass ratio of 6:1.6:0.8.
[0032] Comparative Example 5: The mass ratio of the high-pressure modified fiber was adjusted; the rest was the same as in Example 2; the specific differences are as follows: The high-pressure modified fiber includes pre-modified basalt fiber, 4-(N-maleimide)benzophenone, and pyromellitic diimide in a mass ratio of 8:0.5:0.2.
[0033] Performance testing: The cold-resistant high-voltage outer sheath of the cold-resistant high-voltage cables prepared in Examples 1-3 and Comparative Examples 1-5 was tested. Cold resistance test: Referring to "GB / T1843-2008-Test of impact strength of plastic cantilever beam", the cold-resistant high-pressure outer sheaths of Examples 1-3 and Comparative Examples 1-5 were tested for impact strength at room temperature and low temperature, respectively, and the low-temperature impact strength retention rate was calculated. The test results are shown in Table 1. Table 1
[0034] High voltage stability test: The cold-resistant high voltage outer sheaths of Examples 1-3 and Comparative Examples 1-5 were tested for electric field distortion rate at room temperature. The test results are shown in Table 2. Table 2
[0035] In conclusion, as shown in Tables 1-2 above, the cold-resistant high-voltage cable prepared by this application using a cold-resistant high-voltage outer sheath exhibits good cold resistance and high-voltage stability, meeting the requirements for cold-resistant high-voltage cables. Data from Comparative Example 1 shows that adding high-voltage modified fibers to the first temperature zone prevents the premixed material from melting, thus hindering the effective function of the high-voltage modified fibers and causing agglomeration, resulting in a significant decrease in voltage stability and overall performance. Data from Comparative Example 2 shows that without the addition of high-voltage modified fibers, space charge easily accumulates internally, causing electrical treeing degradation. Furthermore, mechanical properties still decrease at low temperatures, leading to a decline in overall performance. Data from Comparative Example 3 shows that without the addition of hydrogenated styrene-butadiene-styrene block copolymer, ethylene-butadiene... The soft segment of the olefin cannot synergistically produce specific effects with the pre-modified basalt fiber, resulting in a significant decrease in cold resistance. As shown in the data of Comparative Example 4, when the pre-modified basalt fiber is replaced with basalt fiber, the lack of groups such as benzophenone and undecanoate groups leads to a decrease in overall performance. As shown in the data of Comparative Example 5, adjusting the mass ratio in the high-pressure modified fiber results in an excess of pre-modified basalt fiber and an insufficient amount of other components, leading to an imbalance in the ratio and a significant decrease in charge suppression. At the same time, the excessive amount of pre-modified basalt fiber is still prone to agglomeration, which increases the brittleness of the material and reduces its overall performance.
[0036] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. 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 process for the preparation of a cold-resistant high-voltage cable, characterized in that: Includes the following steps: Step 1: Mix high-density polyethylene, linear low-density polyethylene, maleic anhydride-grafted POE, hydrogenated styrene-butadiene-styrene block copolymer, crosslinking agent, antioxidant, and lubricant evenly and stir at high temperature to obtain a premix. Step 2: The premixed material is melt-extruded. The melt extrusion process includes 6 temperature zones. High-pressure modified fibers are added in the fourth temperature zone, and the material is cooled and molded to obtain a cold-resistant high-pressure outer sheath. Step 3: Wrap the cable core with the outer sheath, shielding layer, and insulation layer in sequence to obtain a cold-resistant high-voltage cable; The raw materials of the premix include the following components by weight: 45-55 parts high-density polyethylene, 15-25 parts linear low-density polyethylene, 6-12 parts maleic anhydride-grafted POE, 3-7 parts hydrogenated styrene-butadiene-styrene block copolymer, 1.2-2.5 parts crosslinking agent, 0.2-0.8 parts antioxidant, and 0.1-0.6 parts lubricant; The mass ratio of the premix to the high-pressure modified fiber is 88:(5~8); The high-pressure modified fiber comprises pre-modified basalt fiber in a mass ratio of (5~7):(1.2~2):(0.5~1), 4-(N-maleimide)benzophenone, and pyromellitic diimide; The preparation method of the pre-modified basalt fiber is as follows: Step 1: Mix basalt fiber with hydrochloric acid, place at room temperature for 2-3 hours, wash and dry to obtain acid-etched basalt fiber; Step 2: Add acid-etched basalt fibers and aminosilane coupling agent to an ethanol aqueous solution and react at 60~70℃ for 3~5h to obtain amino-treated basalt fibers; Step 3: Aminated basalt fiber, 4-(N-maleimide)benzophenone, 11-maleimide undecanoate, and triethylamine are added to DMF and reacted at 60-80℃ for 6-8 hours. After purification and drying, pre-modified basalt fiber is obtained. The length of the basalt fiber is 1~3mm; In the aminated basalt fiber, the mass ratio of acid-etched basalt fiber to aminosilane coupling agent is 1:(0.3~0.5); The raw materials for the pre-modified basalt fiber include 5-7 parts of aminated basalt fiber, 2-3 parts of 4-(N-maleimide)benzophenone, 3-4 parts of 11-maleimide undecanoate, and 0.05-0.1 parts of triethylamine.
2. A process for the preparation of a cold-resistant high-voltage cable according to claim 1, characterized in that: The six temperature zones in the melt extrusion process are as follows: the first temperature zone is 140~150℃; the second temperature zone is 150~160℃; the third temperature zone is 160~170℃; the fourth temperature zone is 175~185℃; the fifth temperature zone is 160~170℃; and the sixth temperature zone is 155~160℃.
3. A process for the preparation of a cold-resistant high-voltage cable according to claim 1, characterized in that: The crosslinking agent is dicumyl peroxide; the antioxidant includes one or more of antioxidant 168, antioxidant 1076, and antioxidant 1010; the lubricant includes one or more of zinc stearate, calcium stearate, and ethylene bis-stearamide.
4. The method for preparing a cold-resistant high-voltage cable according to claim 1, characterized in that: The grafting rate of the maleic anhydride grafted POE is 0.6-1.0%; the density of the high-density polyethylene is 0.940-0.976 g / cm 3 ; the crystallinity is 80-90%; the density of the linear low-density polyethylene is 0.911-0.920 g / cm 3 .
5. The cold-resistant high-voltage cable prepared by the method of preparing a cold-resistant high-voltage cable according to any one of claims 1 to 4.