Flame-retardant power cable auxiliary material for electrical equipment and preparation method thereof
By adding specific components to flame-retardant power cable accessories to form a β-crystalline energy consumption network, the problem of low-temperature brittleness is solved, and the low-temperature impact strength and toughness are improved, meeting the requirements for cable use in low-temperature environments.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HEBEI QUANYONG CABLE CO LTD
- Filing Date
- 2026-03-30
- Publication Date
- 2026-05-29
AI Technical Summary
Existing flame-retardant power cable accessories become brittle at low temperatures, resulting in low-temperature impact strength and affecting the cable's low-temperature resistance.
Based on linear low-density polyethylene, ethylene-vinyl acetate copolymer, and ethylene-octene copolymer, N,N′-dicyclohexyl terephthalamide, lanthanum stearate, calcium complex, etc. are added to form a β-crystalline energy dissipation network, which improves the low-temperature toughness and impact strength of the material.
While maintaining good flame retardancy, the low-temperature impact strength of the cable accessories has been improved, extending the service life and meeting higher requirements for low-temperature performance.
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Abstract
Description
Technical Field
[0001] This application relates to the field of cable technology, and more specifically, to a flame-retardant power cable auxiliary material for electrical equipment and its preparation method. Background Technology
[0002] With the rapid development of modern technology, cables have become an indispensable basic component in many fields such as power transmission, communication networks, rail transportation, new energy equipment, and building electrical systems. As the core carrier of energy and signal transmission, cables are used in increasingly complex scenarios, and the requirements for their performance are constantly increasing. Especially in cold regions, low-temperature storage, or extremely cold outdoor environments, cables need to possess both excellent low-temperature resistance and reliable flame-retardant properties to ensure the stability and safety of power transmission. Existing cables generally include a cable core and an outer sheath surrounding the core. The outer sheath is made from flame-retardant power cable auxiliary materials through extrusion. The raw material for flame-retardant power cable auxiliary materials is mostly polyethylene. To increase flame retardancy, flame retardants are often added to the raw material to prevent combustion. However, in low-temperature environments, flame-retardant power cable auxiliary materials are prone to brittleness, resulting in lower low-temperature impact strength and affecting the cable's low-temperature resistance. Summary of the Invention
[0003] While maintaining the good flame retardancy of flame-retardant power cable accessories, in order to improve low-temperature impact strength and enhance low-temperature resistance, this application provides a flame-retardant power cable accessory for electrical equipment and its preparation method.
[0004] In a first aspect, this application provides a flame-retardant power cable accessory for electrical equipment, employing the following technical solution: A flame-retardant power cable auxiliary material for electrical equipment is mainly made of the following raw materials in parts by weight: 40-50 parts of linear low-density polyethylene, 35-45 parts of ethylene-vinyl acetate copolymer, 15-25 parts of ethylene-octene copolymer, 0.3-0.8 parts of N,N′-dicyclohexyl terephthalamide, 0.1-0.5 parts of lanthanum stearate, 0.1-0.5 parts of calcium complex, 8-12 parts of compatibilizer, 25-35 parts of flame retardant, 0.5-1.5 parts of lubricant, and 1-2 parts of antioxidant.
[0005] The flame-retardant power cable auxiliary material for electrical equipment disclosed in this application, through the synergistic effect of the raw materials, achieves a tensile strength >24MPa and an impact strength >48kJ / m at 25℃. 2 Impact strength at -40℃ > 37kJ / m 2 Impact strength at -60℃ >19kJ / m 2 It not only has good flame retardancy, but also good tensile strength and low-temperature impact strength, which can improve low-temperature performance, extend service life, and meet higher requirements.
[0006] The flame-retardant power cable accessory of this application is based on linear low-density polyethylene, with the addition of ethylene-vinyl acetate copolymer and ethylene-octene copolymer. The combination of these compounds increases flexibility and toughness. Furthermore, N,N′-dicyclohexyl terephthalamide, lanthanum stearate, and calcium complex are added. The synergistic effect of these compounds not only induces the formation of β-crystals in the matrix, but also creates an energy-dissipating network within the matrix, rapidly transferring stress. This process also refines the grain size, reducing the β-crystal size to below 5 μm, increasing the grain boundary area per unit volume, and improving energy consumption. This allows the flame-retardant power cable accessory to maintain excellent toughness even at -60°C.
[0007] Optionally, the calcium complex is selected from one or a combination of several of calcium amide carboxylate, calcium stearate, calcium sebacic acid, and calcium pimelic acid. Preferably, the calcium complex is selected from calcium amide carboxylate.
[0008] By adopting the above technical solution, the calcium complex is optimized, facilitating its selection. Furthermore, calcium amide carboxylate contains an amide group, which can synergistically interact with N,N′-dicyclohexyl-terephthalamide, enhancing the effectiveness of the calcium complex and improving the low-temperature impact strength of flame-retardant power cable accessories.
[0009] Optionally, the linear low-density polyethylene has a melt index of 1-3 g / 10 min at 190°C and 2.16 kg; the ethylene-vinyl acetate copolymer has a melt index of 3-6 g / 10 min at 190°C and 2.16 kg; and the ethylene-octene copolymer has a melt index of 1-3 g / 10 min at 190°C and 2.16 kg.
[0010] By adopting the above technical solution, and with the melt indexes of linear low-density polyethylene, ethylene-vinyl acetate copolymer, and ethylene-octene copolymer all controlled within the range of 1-6 g / 10 min, and the melt indices being similar, it is beneficial to the dispersion of linear low-density polyethylene, ethylene-vinyl acetate copolymer, and ethylene-octene copolymer, and ensures the uniformity of raw material dispersion.
[0011] In several embodiments, the melt index of linear low-density polyethylene at 190°C and 2.16 kg is 2 g / 10 min. The melt index can also be set to 1 g / 10 min, 1.3 g / 10 min, 1.5 g / 10 min, 2.3 g / 10 min, 2.5 g / 10 min, 2.8 g / 10 min, 3 g / 10 min, etc., as needed, but is not limited to the listed values. Other unlisted values within this range are also applicable.
[0012] In several embodiments, the melt index of the ethylene-vinyl acetate copolymer at 190°C and 2.16 kg is 4 g / 10 min. The melt index can also be set to 3 g / 10 min, 3.3 g / 10 min, 3.5 g / 10 min, 4.3 g / 10 min, 4.5 g / 10 min, 5 g / 10 min, 5.3 g / 10 min, 5.5 g / 10 min, 5.8 g / 10 min, 6 g / 10 min, etc., as needed, but is not limited to the listed values. Other unlisted values within this range are also applicable.
[0013] In several embodiments, the melt index of the ethylene-octene copolymer at 190°C and 2.16 kg is 2 g / 10 min. The melt index can also be set to 1 g / 10 min, 1.3 g / 10 min, 1.5 g / 10 min, 2.3 g / 10 min, 2.5 g / 10 min, 2.8 g / 10 min, 3 g / 10 min, etc., as needed, but is not limited to the listed values. Other unlisted values within this range are also applicable.
[0014] Optionally, the vinyl acetate content in the ethylene-vinyl acetate copolymer is 18-32%; the octene content in the ethylene-octene copolymer is 20-30%.
[0015] By adopting the above technical solutions, the vinyl acetate content in the ethylene-vinyl acetate copolymer and the octene content in the ethylene-octene copolymer are controlled, ensuring that the flame-retardant power cable accessories can still effectively absorb impact energy at low temperatures, which is beneficial to improving the low-temperature impact strength of the flame-retardant power cable accessories.
[0016] In several embodiments, the vinyl acetate content in the ethylene-vinyl acetate copolymer is 26%. However, the vinyl acetate content can be set to 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 27%, 28%, 29%, 30%, 31%, 32%, etc., as needed, but is not limited to the listed values; other unlisted values within this range are also applicable. Similarly, in several embodiments, the octene content in the ethylene-octene copolymer is 24%. However, the octene content can be set to 20%, 21%, 22%, 23%, 25%, 26%, 27%, 28%, 29%, 30%, etc., as needed, but is not limited to the listed values; other unlisted values within this range are also applicable.
[0017] Optionally, the compatibilizer is selected from one or a combination of maleic anhydride-grafted PE, maleic anhydride-grafted PP, maleic anhydride-grafted POE, maleic anhydride-grafted EVA, and maleic anhydride-grafted EPDM.
[0018] Optionally, the compatibilizer is selected from maleic anhydride-grafted PE with a grafting rate of 1-1.5% and a melt index of 1-5 g / 10 min at 190°C and 2.16 kg.
[0019] By adopting the above technical solution, the compatibilizer is optimized, facilitating its selection. Furthermore, it increases the uniformity of raw material mixing, enhances interfacial bonding strength, and ensures that the flame-retardant power cable auxiliary material possesses excellent mechanical properties.
[0020] In several implementations, the grafting rate of maleic anhydride-grafted PE is 1.1%, and its melt index at 190°C and 2.16 kg is 3 g / 10 min. The grafting rate can also be set to 1%, 1.2%, 1.3%, 1.4%, 1.5%, etc., as needed. The melt index can also be set to 1 g / 10 min, 1.3 g / 10 min, 1.5 g / 10 min, 1.8 g / 10 min, 2 g / 10 min, 2.3 g / 10 min, 2.5 g / 10 min, 2.8 g / 10 min, 3.3 g / 10 min, 3.5 g / 10 min, 3.8 g / 10 min, 4 g / 10 min, 4.3 g / 10 min, 4.5 g / 10 min, 4.8 g / 10 min, 5 g / 10 min, etc., but is not limited to the listed values; other unlisted values within this range are also applicable.
[0021] Optionally, the flame retardant is selected from a combination of magnesium hydroxide, aluminum hydroxide, and zinc borate, and the weight ratio of magnesium hydroxide, aluminum hydroxide, and zinc borate is (65-75):(20-30):(3-8).
[0022] By employing the above technical solution, aluminum hydroxide decomposes endothermally at 235-350℃, and magnesium hydroxide decomposes endothermally at 340-490℃. The combination of these two compounds can cover a wide temperature range from 235℃ to 490℃, achieving continuous heat absorption and cooling. Zinc borate melts endothermally under flame and decomposes to produce water vapor, forming a glassy coating layer. Simultaneously, it promotes polymer carbonization, providing a triple flame-retardant function of cooling, dilution, and coating. This application utilizes a compound of magnesium hydroxide, aluminum hydroxide, and zinc borate to achieve a UL94 V-0 flame-retardant rating, meeting flame-retardant requirements.
[0023] In several implementation schemes, the weight ratio of magnesium hydroxide, aluminum hydroxide, and zinc borate is 70:25:5. However, the weight ratio can also be set to 65:20:3, 65:20:8, 65:30:3, 65:30:8, 75:20:3, 75:20:8, 75:30:3, 75:30:8, etc., as needed. But it is not limited to the listed values; other unlisted values within this range are also applicable.
[0024] Optionally, the lubricant is selected from one or a combination of several of ethylene bis-stearamide, oleamide, erucamide, calcium stearate, and zinc stearate.
[0025] By adopting the above technical solution, the lubricant is optimized, making lubricant selection easier. Furthermore, it can reduce the coefficient of friction between the substrate and processing equipment, facilitating extrusion and improving surface finish.
[0026] Optionally, the antioxidant is selected from one or a combination of antioxidant 1010, antioxidant 1076, antioxidant 3114, antioxidant 168, antioxidant 626, and antioxidant 1330.
[0027] Preferably, the antioxidant is selected from a combination of antioxidant 1010 and antioxidant 168, and the weight ratio of antioxidant 1010 and antioxidant 168 is (1-3):(1-3).
[0028] By adopting the above technical solution, the antioxidant is optimized, facilitating its selection. Furthermore, it increases the thermal stability during processing and improves long-term thermal stability, extending service life. In several embodiments, the weight ratio of antioxidant 1010 and antioxidant 168 is 1:2. However, the weight ratio can also be set to 1:1, 1:3, 2:1, 2:3, 3:1, 3:2, etc., as needed, but is not limited to the listed values; other unlisted values within this range are also applicable.
[0029] Secondly, this application provides a method for preparing the flame-retardant power cable auxiliary material for electrical equipment, which adopts the following technical solution: A method for preparing the flame-retardant power cable auxiliary material for electrical equipment includes the following steps: Linear low-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-octene copolymer, N,N′-dicyclohexyl terephthalamide, lanthanum stearate, calcium complex, compatibilizer, flame retardant, lubricant, and antioxidant are mixed, melted, and extruded into granules to obtain flame-retardant power cable accessories.
[0030] Optionally, a twin-screw extruder is used for melting, extrusion, and granulation. The temperature settings for each section of the twin-screw extruder are as follows: Zone 1: 140-160℃, Zone 2: 150-170℃, Zone 3: 160-180℃, Zone 4: 165-185℃, and the die head: 165-185℃. The screw speed is 300-500 r / min.
[0031] By adopting the above technical solution, the raw materials are fully melted, increasing the uniformity of dispersion and ensuring the quality of flame-retardant power cable accessories. In several implementation schemes, the temperatures of each section of the twin-screw extruder are set as follows: Zone 1: 150℃, Zone 2: 160℃, Zone 3: 170℃, Zone 4: 175℃, and the die head: 175℃, with a screw speed of 350 r / min. Alternatively, the temperature of Zone 1 can be set to 140℃, 145℃, 155℃, 160℃, etc., as needed; the temperature of Zone 2 can be set to 150℃, 155℃, 165℃, 170℃, etc., as needed; and the temperature of Zone 3 can be set to 160℃, 175℃, 175℃, 175℃, etc., as needed. The temperature ranges are 65℃, 175℃, 180℃, etc., and the four-zone temperature can also be set to 165℃, 170℃, 180℃, 185℃, etc., as needed. The head temperature can also be set to 165℃, 170℃, 180℃, 185℃, etc., as needed. The screw speed can also be set to 300r / min, 400r / min, 450r / min, 500r / min, etc., as needed. However, it is not limited to the listed values, and other unlisted values within this range are also applicable.
[0032] In summary, this application has at least the following beneficial effects: The flame-retardant power cable auxiliary material for electrical equipment disclosed in this application is based on a ternary resin formed from linear low-density polyethylene, ethylene-vinyl acetate copolymer, and ethylene-octene copolymer, with the addition of flame retardants to maintain good flame retardancy. N,N′-dicyclohexyl terephthalamide, lanthanum stearate, and calcium complex are also added to induce the matrix to form a β-crystal structure and create an energy-dissipating network for rapid stress transfer. This also refines the grains, increases the grain boundary area per unit volume, and improves energy consumption, resulting in a tensile strength >24 MPa and an impact strength >48 kJ / m at 25°C for the flame-retardant power cable auxiliary material. 2 Impact strength at -60℃ >19kJ / m 2 While maintaining good flame retardancy, improving low-temperature impact strength is beneficial for improving low-temperature resistance, extending service life, and meeting higher requirements. Detailed Implementation
[0033] The present application will be further described in detail below with reference to the embodiments. These embodiments are for illustrative purposes only and are not limited to the scope of application of the present application. Unless otherwise specified, the raw materials or components used in the present application can be obtained commercially or by conventional methods.
[0034] Example Table 1. Raw material consumption of flame-retardant power cable accessories (unit: kg) .
[0035] Example 1 A flame-retardant power cable auxiliary material for electrical equipment, the raw materials and their proportions are shown in Table 1.
[0036] The density of linear low-density polyethylene is 0.922 g / cm³. 3 The melt index of 2.16 kg at 190℃ is 2 g / 10 min; the vinyl acetate content of the ethylene-vinyl acetate copolymer is 26%, and the melt index of 2.16 kg at 190℃ is 4 g / 10 min; the octene content of the ethylene-octene copolymer is 24%, and the melt index of 2.16 kg at 190℃ is 2 g / 10 min.
[0037] The calcium complex is selected from calcium amide carboxylate; the compatibilizer is selected from maleic anhydride-grafted PE with a grafting rate of 1.1% and a melt index of 3 g / 10 min at 190℃ and 2.16 kg; the flame retardant is selected from a combination of magnesium hydroxide, aluminum hydroxide, and zinc borate, with a weight ratio of 70:25:5; the lubricant is selected from ethylene bis-stearamide; the antioxidant is selected from a combination of antioxidant 1010 and antioxidant 168, with a weight ratio of 1:2.
[0038] A method for preparing a flame-retardant power cable accessory for electrical equipment includes the following steps: Linear low-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-octene copolymer, N,N′-dicyclohexyl terephthalamide, lanthanum stearate, calcium complex, compatibilizer, flame retardant, lubricant, and antioxidant are added to a mixer and stirred for 10 minutes. Then, the mixture is transferred to a twin-screw extruder for melt extrusion and granulation to obtain flame-retardant power cable accessories.
[0039] The temperature settings for each section of the twin-screw extruder are as follows: Zone 1: 150℃, Zone 2: 160℃, Zone 3: 170℃, Zone 4: 175℃, and the die head: 175℃. The screw speed is 350 r / min.
[0040] Example 2 A flame-retardant power cable accessory for electrical equipment differs from Example 1 in that the raw material ratio of the flame-retardant power cable accessory is different, and the raw material ratio of the flame-retardant power cable accessory is shown in Table 1.
[0041] Example 3 A flame-retardant power cable accessory for electrical equipment differs from Example 1 in that the raw material ratio of the flame-retardant power cable accessory is different, and the raw material ratio of the flame-retardant power cable accessory is shown in Table 1.
[0042] Comparative Example Comparative Example 1 A flame-retardant power cable accessory for electrical equipment differs from Example 1 in that the raw materials of the flame-retardant power cable accessory do not contain N,N′-dicyclohexyl terephthalamide, lanthanum stearate, or calcium complex.
[0043] Comparative Example 2 A flame-retardant power cable accessory for electrical equipment differs from Example 1 in that an equal amount of N,N′-dicyclohexyl terephthalamide is used to replace the lanthanum stearate and calcium complex in the raw materials of the flame-retardant power cable accessory.
[0044] Comparative Example 3 A flame-retardant power cable accessory for electrical equipment differs from Example 1 in that, in the raw materials of the flame-retardant power cable accessory, an equal amount of lanthanum stearate replaces N,N′-dicyclohexyl terephthalamide and calcium complex.
[0045] Comparative Example 4 A flame-retardant power cable accessory for electrical equipment differs from Example 1 in that an equal amount of calcium complex replaces N,N′-dicyclohexylterephthalamide and lanthanum stearate in the raw materials of the flame-retardant power cable accessory.
[0046] Performance testing Flame-retardant power cable accessories obtained in Examples 1-3 and Comparative Examples 1-4 were taken as samples, and the following performance tests were conducted on the flame-retardant power cable accessories. The test results are shown in Table 2.
[0047] In accordance with GB / T1040.1-2018 "Determination of tensile properties of plastics - Part 1: General", the tensile strength of flame-retardant power cable accessories was tested.
[0048] The impact strength of flame-retardant power cable accessories was tested according to GB / T1043.1-2018 "Determination of impact properties of simply supported plastic beams - Part 1: Non-instrumental impact test".
[0049] According to GB / T2408-2021 "Determination of the flammability of plastics - Horizontal and Vertical Methods", the vertical flame retardancy rating of flame-retardant power cable accessories was tested.
[0050] Table 2 Test Results
[0051] As shown in Table 2, the flame-retardant power cable accessory of this application has good tensile strength and vertical flame retardancy rating. The tensile strength is >24MPa and the vertical flame retardancy rating is V-0, demonstrating good tensile strength. Furthermore, it also has high impact strength, with an impact strength at 25℃ >48kJ / m. 2Impact strength at -40℃ > 37kJ / m 2 Impact strength at -60℃ >19kJ / m 2 It exhibits high low-temperature impact resistance. In other words, the flame-retardant power cable auxiliary material of this application, through the synergistic effect of the raw materials, possesses good tensile strength, good low-temperature impact strength, and good flame-retardant properties, thereby improving low-temperature resistance, extending service life, and meeting market demands.
[0052] Comparative Examples 1-4 were compared. In Comparative Example 2, compared to Comparative Example 1, N,N′-dicyclohexyl terephthalamide was added to the raw materials of the flame-retardant power cable accessory; in Comparative Example 3, compared to Comparative Example 1, lanthanum stearate was added to the raw materials of the flame-retardant power cable accessory; and in Comparative Example 4, compared to Comparative Example 1, a calcium complex was added to the raw materials of the flame-retardant power cable accessory. This shows that while adding N,N′-dicyclohexyl terephthalamide, lanthanum stearate, or a calcium complex alone to the raw materials of the flame-retardant power cable accessory can increase low-temperature impact strength to some extent, the performance improvement is limited. Furthermore, in Example 1, compared to Comparative Example 1, N,N′-dicyclohexyl terephthalamide, lanthanum stearate, and a calcium complex were added to the raw materials of the flame-retardant power cable accessory. This demonstrates that the simultaneous addition of N,N′-dicyclohexyl terephthalamide, lanthanum stearate, and calcium complex to the raw materials of flame-retardant power cable accessories significantly improves low-temperature impact strength. This is likely because the combination of these three components not only generates β-crystals in the matrix but also results in higher β-crystal content, finer crystal size, and better stability, thus maintaining excellent toughness even at -60℃.
[0053] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.
Claims
1. A flame-retardant power cable accessory for electrical equipment, characterized in that: It is mainly made of the following raw materials in parts by weight: 40-50 parts linear low-density polyethylene, 35-45 parts ethylene-vinyl acetate copolymer, 15-25 parts ethylene-octene copolymer, 0.3-0.8 parts N,N′-dicyclohexyl terephthalamide, 0.1-0.5 parts lanthanum stearate, 0.1-0.5 parts calcium complex, 8-12 parts compatibilizer, 25-35 parts flame retardant, 0.5-1.5 parts lubricant, and 1-2 parts antioxidant.
2. The flame-retardant power cable accessory for electrical equipment according to claim 1, characterized in that: The calcium complex is selected from one or a combination of several of calcium amide carboxylate, calcium stearate, calcium sebacic acid, and calcium pimelic acid.
3. The flame-retardant power cable accessory for electrical equipment according to claim 1, characterized in that: The linear low-density polyethylene has a melt index of 1-3 g / 10 min at 190°C and 2.16 kg; the ethylene-vinyl acetate copolymer has a melt index of 3-6 g / 10 min at 190°C and 2.16 kg; and the ethylene-octene copolymer has a melt index of 1-3 g / 10 min at 190°C and 2.16 kg.
4. The flame-retardant power cable accessory for electrical equipment according to claim 1, characterized in that: The vinyl acetate content in the ethylene-vinyl acetate copolymer is 18-32%; the octene content in the ethylene-octene copolymer is 20-30%.
5. The flame-retardant power cable accessory for electrical equipment according to claim 1, characterized in that: The compatibilizer is selected from one or a combination of maleic anhydride-grafted PE, maleic anhydride-grafted PP, maleic anhydride-grafted POE, maleic anhydride-grafted EVA, and maleic anhydride-grafted EPDM.
6. The flame-retardant power cable accessory for electrical equipment according to claim 1, characterized in that: The flame retardant is selected from a combination of magnesium hydroxide, aluminum hydroxide, and zinc borate, and the weight ratio of magnesium hydroxide, aluminum hydroxide, and zinc borate is (65-75):(20-30):(3-8).
7. The flame-retardant power cable accessory for electrical equipment according to claim 1, characterized in that: The lubricant is selected from one or a combination of several of ethylene bis-stearamide, oleamide, erucamide, calcium stearate, and zinc stearate.
8. The flame-retardant power cable accessory for electrical equipment according to claim 1, characterized in that: The antioxidant is selected from one or a combination of several of antioxidants 1010, 1076, 3114, 168, 626, and 1330.
9. The flame-retardant power cable accessory for electrical equipment according to claim 1, characterized in that: The antioxidant is selected from a combination of antioxidant 1010 and antioxidant 168, and the weight ratio of antioxidant 1010 and antioxidant 168 is (1-3):(1-3).
10. A method for preparing flame-retardant power cable accessories for electrical equipment as described in any one of claims 1-9, characterized in that: Includes the following steps: Linear low-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-octene copolymer, N,N′-dicyclohexyl terephthalamide, lanthanum stearate, calcium complex, compatibilizer, flame retardant, lubricant, and antioxidant are mixed, melted, and extruded into granules to obtain flame-retardant power cable accessories.