A low-smoke halogen-free heat-resistant flame-retardant environment-friendly cable for new energy storage systems and a preparation method thereof

Abstract

The present application relates to the technical field of cable, in particular to a low-smoke halogen-free heat-resistant flame-retardant environment-friendly cable for new energy storage system and a preparation method thereof.The present application prepares cable material by loading long-chain alkyl grafting type hindered phenol intermediate carrier, adding segmented cerium silanate, mixing magnesium hydroxide in two sections and adding dilauryl thiodipropionate in the later section, and then cross-linking the cable material by electron beam irradiation.The obtained cable has a fracture elongation retention rate of 78.6% after aging at 180 DEG C for 168 hours, only 0.3 cracks per 10 m after 200 cold and hot cycles, and an oxygen index of 38.9%, and has excellent heat resistance, flame retardance and insulation performance, and is suitable for long-term temperature rise scenes such as energy storage cabinets and battery clusters.

Description

Technical Field

[0001] This invention relates to the field of cable technology, and in particular to a low-smoke, halogen-free, heat-resistant, flame-retardant, and environmentally friendly cable for new energy storage systems and its preparation method. Background Technology

[0002] As a key support for clean energy consumption and grid regulation, the large-scale application of new energy storage systems places stringent requirements on the temperature resistance, flame retardancy, and long-term reliability of supporting cables. Currently, low-smoke halogen-free flame-retardant polyolefin cable materials have become the mainstream choice for energy storage system wiring due to their low smoke density and zero halogen release during combustion. Conventional technical approaches often use polyolefin elastomers such as EVA and POE as the matrix, combined with high-filled magnesium hydroxide to achieve flame retardancy, and supplemented with conventional antioxidants and lubricants to improve processing performance.

[0003] However, such systems have revealed significant defects in practical applications: the inorganic interface with high magnesium hydroxide content is prone to adsorption and consumption of anti-thermal-oxidative aging components, causing them to migrate and precipitate to the interface during processing heating and long-term service, making it difficult to continuously play a protective role; at the same time, in energy storage scenarios, cables need to withstand long-term temperature rise, short-term overload, and thermal cycling from -40℃ to 150℃. Conventional formulations are prone to problems such as a sharp drop in mechanical properties after aging in hot air at 180℃ and cracking of the insulation layer after thermal cycling. Moreover, it is difficult to improve flame retardant performance and thermal-oxidative stability in a coordinated manner, which restricts the safe operation of energy storage systems. Summary of the Invention

[0004] In view of this, the purpose of this invention is to propose a low-smoke halogen-free heat-resistant and flame-retardant environmentally friendly cable for new energy storage systems and its preparation method, so as to reduce the migration loss of anti-thermal oxidative aging agents in high-filled magnesium hydroxide low-smoke halogen-free polyolefin cable material, and improve the mechanical retention rate and cold and hot cycle crack resistance after 180℃ thermal aging.

[0005] To achieve the above objectives, the present invention provides a low-smoke halogen-free, heat-resistant, flame-retardant, and environmentally friendly cable for new energy storage systems, comprising a conductor and an insulating protective layer covering the outer surface of the conductor, wherein the insulating protective layer is prepared from low-smoke halogen-free, heat-resistant, flame-retardant, and environmentally friendly cable material for new energy storage systems.

[0006] By weight, the low-smoke halogen-free heat-resistant flame-retardant environmentally friendly cable material is prepared from the following raw materials: 480-560 parts ethylene-vinyl acetate copolymer, 130-200 parts ethylene-octene copolymer, 70-100 parts maleic anhydride grafted polyolefin elastomer, 260-340 parts anti-aging masterbatch, 1400-1600 parts surface-treated magnesium hydroxide, 5-12 parts octadecylsilane-modified cerium oxide, 10-15 parts zinc stearate, and 6-10 parts dilaurate thiodipropionate. The anti-aging masterbatch is prepared from a polyolefin-compatible heat- and oxygen-resistant aging agent carrier masterbatch and aminosilanized cerium oxide. The polyolefin-compatible heat- and oxygen-resistant aging agent carrier masterbatch is prepared from a long-chain alkyl-grafted hindered phenol intermediate and a maleic anhydride-grafted polyolefin elastomer. The long-chain alkyl-grafted hindered phenol intermediate is obtained by reacting 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid with C16-C22 long-chain fatty acid glycidyl ester.

[0007] Preferably, the anti-aging masterbatch is obtained by mixing and pelletizing 288-297 parts of polyolefin-compatible heat-resistant and oxygen-resistant aging agent carrier masterbatch and 3-12 parts of aminosilanized cerium oxide.

[0008] Preferably, the polyolefin-compatible heat-oxidative aging agent carrier masterbatch is obtained by mixing and pelletizing 1000 parts of maleic anhydride-grafted polyolefin elastomer, 50-75 parts of long-chain alkyl-grafted hindered phenol intermediate, and 3-5 parts of zinc stearate.

[0009] Preferably, the long-chain alkyl-grafted hindered phenolic intermediate is obtained by reacting 500 parts of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid, 586-739 parts of C16-C22 long-chain fatty acid glycidyl esters, and 4-8 parts of triphenylphosphine.

[0010] Preferably, the C16-C22 long-chain fatty acid glycidyl ester is glycidyl palmitate, glycidyl stearate, glycidyl eicosanoate, or glycidyl dodecanoate.

[0011] Preferably, the aminosilanized cerium oxide is obtained by reacting 50 parts of nano-cerium oxide, 1.5-2.5 parts of 3-aminopropyltriethoxysilane, 150 parts of anhydrous ethanol, 12-18 parts of deionized water and 0.8-1.2 parts of glacial acetic acid.

[0012] Preferably, the octadecylsilane cerium oxide is obtained by reacting 50 parts of nano-cerium oxide, 2.5-3.5 parts of octadecyltrimethoxysilane, 150 parts of isopropanol, 9-12 parts of deionized water and 0.8-1.2 parts of glacial acetic acid.

[0013] Preferably, the vinyl acetate content of the ethylene-vinyl acetate copolymer is 30wt%-35wt%, and the melt flow rate at 190℃ and 2.16kg is 0.1-0.3g / 10min; the melt flow rate of the ethylene-octene copolymer at 190℃ and 2.16kg is 0.4-0.6g / 10min.

[0014] Preferably, the surface-treated magnesium hydroxide comprises a first part of surface-treated magnesium hydroxide and a second part of surface-treated magnesium hydroxide, wherein the first part of surface-treated magnesium hydroxide comprises 730-850 parts and the second part of surface-treated magnesium hydroxide comprises 670-750 parts; the first part of surface-treated magnesium hydroxide is added after compounding ethylene-vinyl acetate copolymer, ethylene-octene copolymer, maleic anhydride grafted polyolefin elastomer and anti-aging masterbatch; the second part of surface-treated magnesium hydroxide is added together with octadecylsilane-modified cerium oxide and zinc stearate.

[0015] Furthermore, the present invention also provides a method for preparing a low-smoke, halogen-free, heat-resistant, flame-retardant, and environmentally friendly cable for a new energy storage system, comprising the following steps: (1) Preparation of long-chain alkyl-grafted hindered phenol intermediates; (2) Maleic anhydride-grafted polyolefin elastomer, the long-chain alkyl-grafted hindered phenol intermediate and zinc stearate are mixed to obtain polyolefin-compatible heat-oxidative aging agent carrier masterbatch. (3) Prepare aminosilanized cerium oxide and octadecylsilanized cerium oxide respectively; (4) The polyolefin-compatible heat-resistant and oxygen-resistant aging agent carrier masterbatch and aminosilanized cerium oxide are mixed to obtain an anti-aging masterbatch; (5) Ethylene-vinyl acetate copolymer, ethylene-octene copolymer, maleic anhydride grafted polyolefin elastomer, the anti-aging masterbatch, surface-treated magnesium hydroxide, octadecylsilane cerium oxide, zinc stearate and dilaurate thiodipropionate are mixed and extruded to obtain low-smoke halogen-free heat-resistant flame-retardant environmentally friendly cable material for new energy storage systems. (6) Dry the low-smoke halogen-free heat-resistant flame-retardant environmentally friendly cable material for new energy storage systems at 80°C for 4 hours, preheat the conductor to 60°C, and use an extruder to extrude the cable material onto the outer surface of the conductor to form an insulating protective layer. After cooling in a water tank and winding, use an electron beam irradiation crosslinking process with an irradiation dose of 80 kGy to obtain the low-smoke halogen-free heat-resistant flame-retardant environmentally friendly cable for new energy storage systems.

[0016] Preferably, the preparation of the polyolefin-compatible heat- and oxygen-resistant aging agent carrier masterbatch includes: drying 1000 parts of maleic anhydride-grafted polyolefin elastomer at 78-85°C for 3-5 hours; adding the dried maleic anhydride-grafted polyolefin elastomer, 50-75 parts of long-chain alkyl-grafted hindered phenol intermediate, and 3-5 parts of zinc stearate into an internal mixer; mixing at 160-170°C and 75-85 rpm for 12-13 minutes; then vacuuming to an absolute pressure ≤20 kPa and continuing to mix for 5 minutes; and finally discharging and pelletizing to obtain the polyolefin-compatible heat- and oxygen-resistant aging agent carrier masterbatch.

[0017] Preferably, the preparation of the anti-aging masterbatch includes: taking 288-297 parts of polyolefin-compatible heat-resistant and oxygen-resistant aging agent carrier masterbatch and 3-12 parts of aminosilanized cerium oxide and adding them to a mixer, mixing them at 118-122°C and 60 rpm for 10 min, discharging and pelletizing to obtain the anti-aging masterbatch.

[0018] Preferably, the mixing and extrusion granulation includes: first, adding 480-560 parts of ethylene-vinyl acetate copolymer, 130-200 parts of ethylene-octene copolymer, 70-100 parts of maleic anhydride-grafted polyolefin elastomer, and 260-340 parts of anti-aging masterbatch to a mixer and mixing for 5 minutes at 124-126°C and 70 rpm; then adding 730-850 parts of surface-treated magnesium hydroxide and mixing for 5 minutes; next, adding 670-750 parts of surface-treated magnesium hydroxide, 5-12 parts of octadecylsilane-modified cerium oxide, and 10-15 parts of zinc stearate and mixing for 10 minutes at 138-142°C and 70 rpm; finally, reducing the material temperature in the mixer to 118°C, adding 6-10 parts of dilauryl thiodipropionate and mixing for 4 minutes, and then extruding and granulating the material in a twin-screw extruder to obtain low-smoke halogen-free, heat-resistant, flame-retardant, and environmentally friendly cable material.

[0019] Preferably, the temperature of the twin-screw extruder is 120°C in zone one, 130°C in zone two, 140°C in zone three, 145°C in zone four, and 140°C at the die head.

[0020] The beneficial effects of this invention are: (1) This invention prepares a long-chain alkyl-grafted hindered phenolic intermediate by ring-opening esterification of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid with C16-C22 long-chain fatty acid glycidyl ester, and loads it onto a maleic anhydride-grafted polyolefin elastomer to obtain a compatible thermo-oxidative aging agent carrier masterbatch, which effectively inhibits the migration and premature consumption of antioxidants to the inorganic filler interface. Data shows that the oxidation induction time at 200℃ in Example 1 reached 53.6 min, which is 176% higher than that in Comparative Example 1 without the introduction of this intermediate, significantly extending the thermo-oxidative stability window of the material.

[0021] (2) In this invention, nano-cerium oxide is prepared in two forms: aminosilanized and octadecylsilanized. These forms are added in stages to the anti-aging masterbatch and the second batch of magnesium hydroxide, which not only enhances the antioxidant capacity of the resin phase but also stabilizes the interfacial bonding of the filler. After 200 cycles of thermal cycling from -40°C to 150°C, Example 6 showed only 0.3 cracks per 10m, far lower than the 7.4 cracks per 10m in Comparative Example 7, significantly improving the crack resistance in energy storage scenarios.

[0022] (3) The present invention adopts a process of adding magnesium hydroxide in two stages and adding dilauryl thiodipropionate at a low temperature in the later stage. While ensuring excellent flame retardant properties such as oxygen index of 38.9% and minimum light transmittance of 83.4%, it also achieves a 78.6% retention rate of elongation at break after aging at 180℃ for 168h and an insulation resistance constant of 9075.40MΩ·km at 20℃, thus realizing the comprehensive optimization of heat resistance, flame retardancy and insulation. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0024] The specific implementation method uses ethylene-vinyl acetate copolymer EVATHENE UE33002 from Taiwan Polymer Co., Ltd., with a vinyl acetate content of 33wt% and a melt flow rate of 0.20g / 10min at 190℃ and 2.16kg; ethylene-octene copolymer ENGAGE 8150 REN Polyolefin Elastomer from Dow Chemical, with a melt flow rate of 0.50g / 10min at 190℃ and 2.16kg; maleic anhydride grafted polyolefin elastomer MC502 from Ningbo Nengzhiguang New Material Technology Co., Ltd.; surface-treated magnesium hydroxide MAGNIFIN H-5MV from Huber Engineered Materials, with a magnesium hydroxide content ≥99.8% and a median particle size of 1.8μm; nano-cerium oxide Sigma-Aldrich 700290 with a median particle size of 30nm; and zinc stearate Z104437 from Shanghai Aladdin Biochemical Technology Co., Ltd., with a zinc content of 11.5wt% and a particle size of 200 mesh.

[0025] Example 1: Step 1: Add 500g of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid, 630g of glycidyl stearate and 6g of triphenylphosphine to a reactor equipped with a stirrer, thermometer and nitrogen inlet. Start stirring and purge with nitrogen at 20L / h for 30min. Heat the material to 115℃ and react at 120rpm for 4h. After the reaction is complete, maintain 115℃ and evacuate to an absolute pressure ≤20kPa for 20min. Then cool down to 80℃ and discharge to obtain a long-chain alkyl-grafted hindered phenol intermediate. Step 2: Take 1000g of maleic anhydride-grafted polyolefin elastomer and dry it at 80℃ for 4h. Add the dried maleic anhydride-grafted polyolefin elastomer, 60g of the long-chain alkyl-grafted hindered phenol intermediate obtained in Step 1 and 4g of zinc stearate to a mixer and mix at 165℃ and 80rpm for 12min. Then, vacuum the mixture to an absolute pressure ≤20kPa and continue mixing for 5min. Discharge and pelletize to obtain polyolefin-compatible heat-oxidative aging agent carrier masterbatch. Step 3: Take 50g of nano-cerium oxide, 2g of 3-aminopropyltriethoxysilane, 150g of anhydrous ethanol, 15g of deionized water and 1g of glacial acetic acid and add them to the reaction flask. Stir at 300rpm for 20min, then heat to 60℃ and keep warm for 2h. After the reaction is complete, filter and wash the filter cake twice with 100g of anhydrous ethanol. Dry at 90℃ for 4h and then pass through a 200-mesh sieve to obtain aminosilanized cerium oxide. Step 4: Add 50g of nano-cerium oxide, 3g of octadecyltrimethoxysilane, 150g of isopropanol, 10g of deionized water and 1g of glacial acetic acid to a reaction flask, stir at 300rpm for 20min, then heat to 70℃ and keep warm for 3h. After the reaction is complete, filter, wash the filter cake twice with 100g of isopropanol, dry at 90℃ for 4h, and then pass through a 200-mesh sieve to obtain octadecylsilanized cerium oxide. Step 5: Take 294g of the polyolefin-compatible heat-resistant and oxygen-resistant aging agent carrier masterbatch obtained in Step 2 and 6g of the aminosilanized cerium oxide obtained in Step 3 and add them to a mixer. Mix them at 120℃ and 60rpm for 10min, then discharge and pelletize to obtain the anti-aging masterbatch. Step Six: First, add 520g of ethylene-vinyl acetate copolymer, 160g of ethylene-octene copolymer, 80g of maleic anhydride grafted polyolefin elastomer, and 300g of anti-aging masterbatch to a mixer and mix at 125℃ and 70rpm for 5 minutes. Then, add 800g of surface-treated magnesium hydroxide and mix for 5 minutes. Next, add 700g of surface-treated magnesium hydroxide, 8g of octadecylsilane-modified cerium oxide, and 12g of zinc stearate and mix at 140℃ and 70rpm for 10 minutes. Finally, reduce the material temperature in the mixer to 118℃, add 8g of dilauryl thiodipropionate and mix for 4 minutes. After discharge, extrude and granulate the material in a twin-screw extruder at conditions of 120℃ in zone 1, 130℃ in zone 2, 140℃ in zone 3, 145℃ in zone 4, and 140℃ at the die head to obtain low-smoke halogen-free heat-resistant flame-retardant environmentally friendly cable material. Step 7: Dry the cable material obtained in Step 6 at 80℃ for 4 hours. Preheat the Category 5 tin-plated annealed copper stranded wire with a nominal cross-section of 35mm² to 60℃. Extrude the protective layer using an extruder. The extrusion temperature is 120℃ in Zone 1, 135℃ in Zone 2, 145℃ in Zone 3, 150℃ in Zone 4, and 155℃ at the die head. The screw speed is 30rpm. The average thickness of the insulation layer is controlled to be 3mm. After cooling in a 25℃ water bath and winding, the cable is treated with an electron beam irradiation crosslinking process with an irradiation dose of 80kGy to obtain a low-smoke halogen-free heat-resistant flame-retardant environmentally friendly cable for new energy storage systems.

[0026] Example 2: Step 1: Add 500g of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid, 586g of glycidyl palmitate and 5g of triphenylphosphine to a reactor equipped with a stirrer, thermometer and nitrogen inlet. Start stirring and purge with nitrogen at 18L / h for 30min. Heat the material to 112℃ and react at 120rpm for 4.5h. After the reaction is complete, maintain 112℃ and evacuate to an absolute pressure ≤20kPa for 20min. Then cool to 80℃ and discharge to obtain a long-chain alkyl-grafted hindered phenol intermediate. Step 2: Take 1000g of maleic anhydride-grafted polyolefin elastomer and dry it at 80℃ for 4h. Add the dried maleic anhydride-grafted polyolefin elastomer, 55g of the long-chain alkyl-grafted hindered phenol intermediate obtained in Step 1 and 4g of zinc stearate to a mixer and mix at 163℃ and 80rpm for 12min. Then, vacuum the mixture to an absolute pressure ≤20kPa and continue mixing for 5min. Discharge and pelletize to obtain polyolefin-compatible heat-oxidative aging agent carrier masterbatch. Step 3: Take 50g of nano-cerium oxide, 1.8g of 3-aminopropyltriethoxysilane, 150g of anhydrous ethanol, 14g of deionized water and 1g of glacial acetic acid and add them to the reaction flask. Stir at 300rpm for 20min, then heat to 60℃ and keep warm for 2h. After the reaction is complete, filter and wash the filter cake twice with 100g of anhydrous ethanol. Dry at 90℃ for 4h and then pass through a 200-mesh sieve to obtain aminosilanized cerium oxide. Step 4: Add 50g of nano-cerium oxide, 2.8g of octadecyltrimethoxysilane, 150g of isopropanol, 10g of deionized water and 1g of glacial acetic acid to a reaction flask, stir at 300rpm for 20min, then heat to 70℃ and keep warm for 3h. After the reaction is complete, filter, wash the filter cake twice with 100g of isopropanol, dry at 90℃ for 4h, and then pass through a 200-mesh sieve to obtain octadecylsilanized cerium oxide. Step 5: Take 295g of the polyolefin-compatible heat-resistant and oxygen-resistant aging agent carrier masterbatch obtained in Step 2 and 5g of the aminosilanized cerium oxide obtained in Step 3 and add them to a mixer. Mix them at 120℃ and 60rpm for 10 minutes, then discharge and pelletize to obtain the anti-aging masterbatch. Step Six: First, add 540g of ethylene-vinyl acetate copolymer, 150g of ethylene-octene copolymer, 70g of maleic anhydride grafted polyolefin elastomer, and 280g of anti-aging masterbatch to a mixer and mix at 125℃ and 70rpm for 5 minutes. Then, add 760g of surface-treated magnesium hydroxide and mix for 5 minutes. Next, add 740g of surface-treated magnesium hydroxide, 6g of octadecylsilane-modified cerium oxide, and 12g of zinc stearate and mix at 140℃ and 70rpm for 10 minutes. Finally, reduce the material temperature in the mixer to 118℃, add 7g of dilauryl thiodipropionate and mix for 4 minutes. After discharge, extrude and granulate the material in a twin-screw extruder at conditions of 120℃ in zone 1, 130℃ in zone 2, 140℃ in zone 3, 145℃ in zone 4, and 140℃ at the die head to obtain low-smoke halogen-free heat-resistant flame-retardant environmentally friendly cable material. Step 7: Dry the cable material obtained in Step 6 at 80℃ for 4 hours. Preheat the Category 5 tin-plated annealed copper stranded wire with a nominal cross-section of 35mm² to 60℃. Extrude the protective layer using an extruder. The extrusion temperature is 120℃ in Zone 1, 135℃ in Zone 2, 145℃ in Zone 3, 150℃ in Zone 4, and 155℃ at the die head. The screw speed is 30rpm. The average thickness of the insulation layer is controlled to be 3mm. After cooling in a 25℃ water bath and winding, the cable is treated with an electron beam irradiation crosslinking process with an irradiation dose of 80kGy to obtain a low-smoke halogen-free heat-resistant flame-retardant environmentally friendly cable for new energy storage systems.

[0027] Example 3: Step 1: Add 500g of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid, 689g of eicosanoic acid glycidyl ester and 6g of triphenylphosphine to a reactor equipped with a stirrer, thermometer and nitrogen inlet. Start stirring and purge with nitrogen at 20L / h for 30min. Heat the material to 116℃ and react at 125rpm for 4h. After the reaction is complete, maintain 116℃ and evacuate to an absolute pressure ≤20kPa for 25min. Then cool down to 82℃ and discharge to obtain a long-chain alkyl-grafted hindered phenol intermediate. Step 2: Take 1000g of maleic anhydride-grafted polyolefin elastomer and dry it at 80℃ for 4h. Add the dried maleic anhydride-grafted polyolefin elastomer, 65g of the long-chain alkyl-grafted hindered phenol intermediate obtained in Step 1 and 4g of zinc stearate to a mixer and mix at 166℃ and 80rpm for 12min. Then, vacuum the mixture to an absolute pressure ≤20kPa and continue mixing for 5min. Discharge and pelletize to obtain polyolefin-compatible heat-oxidative aging agent carrier masterbatch. Step 3: Take 50g of nano-cerium oxide, 2.2g of 3-aminopropyltriethoxysilane, 150g of anhydrous ethanol, 15g of deionized water and 1g of glacial acetic acid and add them to the reaction flask. Stir at 300rpm for 20min, then heat to 62℃ and keep warm for 2h. After the reaction is complete, filter and wash the filter cake twice with 100g of anhydrous ethanol. Dry at 90℃ for 4h and then pass through a 200-mesh sieve to obtain aminosilanized cerium oxide. Step 4: Add 50g of nano-cerium oxide, 3.2g of octadecyltrimethoxysilane, 150g of isopropanol, 10g of deionized water and 1g of glacial acetic acid to a reaction flask, stir at 300rpm for 20min, then heat to 70℃ and keep warm for 3h. After the reaction is complete, filter, wash the filter cake twice with 100g of isopropanol, dry at 90℃ for 4h, and then pass through a 200-mesh sieve to obtain octadecylsilanized cerium oxide. Step 5: Take 292g of the polyolefin-compatible heat-resistant and oxygen-resistant aging agent carrier masterbatch obtained in Step 2 and 8g of the aminosilanized cerium oxide obtained in Step 3 and add them to a mixer. Mix them at 120℃ and 60rpm for 10 minutes, then discharge and pelletize to obtain the anti-aging masterbatch. Step Six: First, add 500g of ethylene-vinyl acetate copolymer, 180g of ethylene-octene copolymer, 90g of maleic anhydride grafted polyolefin elastomer and 320g of anti-aging masterbatch to a mixer and mix at 125℃ and 70rpm for 5 minutes. Then add 820g of surface-treated magnesium hydroxide and mix for 5 minutes. Next, add 720g of surface-treated magnesium hydroxide, 10g of octadecylsilane-modified cerium oxide and 14g of zinc stearate and mix at 140℃ and 70rpm for 10 minutes. Finally, reduce the material temperature in the mixer to 118℃, add 9g of dilauryl thiodipropionate and mix for 4 minutes. After discharge, extrude and granulate the material in a twin-screw extruder at conditions of 120℃ in zone 1, 130℃ in zone 2, 140℃ in zone 3, 145℃ in zone 4 and 140℃ at the die head to obtain low-smoke halogen-free heat-resistant flame-retardant environmentally friendly cable material. Step 7: Dry the cable material obtained in Step 6 at 80℃ for 4 hours. Preheat the Category 5 tin-plated annealed copper stranded wire with a nominal cross-section of 35mm² to 60℃. Extrude the protective layer using an extruder. The extrusion temperature is 120℃ in Zone 1, 135℃ in Zone 2, 145℃ in Zone 3, 150℃ in Zone 4, and 155℃ at the die head. The screw speed is 30rpm. The average thickness of the insulation layer is controlled to be 3mm. After cooling in a 25℃ water bath and winding, the cable is treated with an electron beam irradiation crosslinking process with an irradiation dose of 80kGy to obtain a low-smoke halogen-free heat-resistant flame-retardant environmentally friendly cable for new energy storage systems.

[0028] Example 4: Step 1: Add 500g of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid, 739g of glycidyl dodecanoate and 7g of triphenylphosphine to a reactor equipped with a stirrer, thermometer and nitrogen inlet. Start stirring and purge with nitrogen at 22L / h for 30min. Heat the material to 118℃ and react at 130rpm for 4h. After the reaction is complete, maintain 118℃ and evacuate to an absolute pressure ≤20kPa for 25min. Then cool down to 82℃ and discharge to obtain a long-chain alkyl-grafted hindered phenol intermediate. Step 2: Take 1000g of maleic anhydride-grafted polyolefin elastomer and dry it at 80℃ for 4h. Add the dried maleic anhydride-grafted polyolefin elastomer, 70g of the long-chain alkyl-grafted hindered phenol intermediate obtained in Step 1 and 5g of zinc stearate to a mixer and mix at 168℃ and 85rpm for 13min. Then, vacuum the mixture to an absolute pressure ≤20kPa and continue mixing for 5min. Discharge and pelletize to obtain polyolefin-compatible heat-oxidative aging agent carrier masterbatch. Step 3: Take 50g of nano-cerium oxide, 2.4g of 3-aminopropyltriethoxysilane, 150g of anhydrous ethanol, 16g of deionized water and 1g of glacial acetic acid and add them to the reaction flask. Stir at 300rpm for 20min, then heat to 62℃ and keep warm for 2h. After the reaction is completed, filter and wash the filter cake twice with 100g of anhydrous ethanol. Dry at 90℃ for 4h and then pass through a 200-mesh sieve to obtain aminosilanized cerium oxide. Step 4: Add 50g of nano-cerium oxide, 3.4g of octadecyltrimethoxysilane, 150g of isopropanol, 10g of deionized water and 1g of glacial acetic acid to a reaction flask, stir at 300rpm for 20min, then heat to 72℃ and keep warm for 3h. After the reaction is complete, filter, wash the filter cake twice with 100g of isopropanol, dry at 90℃ for 4h, and then pass through a 200-mesh sieve to obtain octadecylsilanized cerium oxide. Step 5: Take 288g of the polyolefin-compatible heat-resistant and oxygen-resistant aging agent carrier masterbatch obtained in Step 2 and 12g of the aminosilanized cerium oxide obtained in Step 3 and add them to a mixer. Mix them at 122℃ and 60rpm for 10min, then discharge and pelletize to obtain the anti-aging masterbatch. Step Six: First, add 480g of ethylene-vinyl acetate copolymer, 200g of ethylene-octene copolymer, 100g of maleic anhydride grafted polyolefin elastomer, and 340g of anti-aging masterbatch to a mixer and mix at 126℃ and 70rpm for 5 minutes. Then, add 850g of surface-treated magnesium hydroxide and mix for 5 minutes. Next, add 750g of surface-treated magnesium hydroxide, 12g of octadecylsilane-modified cerium oxide, and 15g of zinc stearate and mix at 142℃ and 70rpm for 10 minutes. Finally, reduce the material temperature in the mixer to 118℃, add 10g of dilauryl thiodipropionate and mix for 4 minutes. After discharge, extrude and granulate the material in a twin-screw extruder at conditions of 120℃ in zone 1, 130℃ in zone 2, 140℃ in zone 3, 145℃ in zone 4, and 140℃ at the die head to obtain low-smoke halogen-free heat-resistant flame-retardant environmentally friendly cable material. Step 7: Dry the cable material obtained in Step 6 at 80℃ for 4 hours. Preheat the Category 5 tin-plated annealed copper stranded wire with a nominal cross-section of 35mm² to 60℃. Extrude the protective layer using an extruder. The extrusion temperature is 120℃ in Zone 1, 135℃ in Zone 2, 145℃ in Zone 3, 150℃ in Zone 4, and 155℃ at the die head. The screw speed is 30rpm. The average thickness of the insulation layer is controlled to be 3mm. After cooling in a 25℃ water bath and winding, the cable is treated with an electron beam irradiation crosslinking process with an irradiation dose of 80kGy to obtain a low-smoke halogen-free heat-resistant flame-retardant environmentally friendly cable for new energy storage systems.

[0029] Example 5: Step 1: Add 500g of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid, 630g of glycidyl stearate and 4g of triphenylphosphine to a reactor equipped with a stirrer, thermometer and nitrogen inlet. Start stirring and purge with nitrogen at 18L / h for 30min. Heat the material to 110℃ and react at 110rpm for 4.5h. After the reaction is complete, maintain 110℃ and evacuate to an absolute pressure ≤20kPa for 20min. Then cool down to 80℃ and discharge to obtain a long-chain alkyl-grafted hindered phenol intermediate. Step 2: Take 1000g of maleic anhydride-grafted polyolefin elastomer and dry it at 80℃ for 4h. Add the dried maleic anhydride-grafted polyolefin elastomer, 50g of the long-chain alkyl-grafted hindered phenol intermediate obtained in Step 1 and 3g of zinc stearate to a mixer and mix at 160℃ and 75rpm for 12min. Then, vacuum the mixture to an absolute pressure ≤20kPa and continue mixing for 5min. Discharge and pelletize to obtain polyolefin-compatible heat-oxidative aging agent carrier masterbatch. Step 3: Take 50g of nano-cerium oxide, 1.5g of 3-aminopropyltriethoxysilane, 150g of anhydrous ethanol, 12g of deionized water and 0.8g of glacial acetic acid and add them to the reaction flask. Stir at 300rpm for 20min, then heat to 58℃ and keep warm for 2h. After the reaction is complete, filter and wash the filter cake twice with 100g of anhydrous ethanol. Dry at 90℃ for 4h and then pass through a 200-mesh sieve to obtain aminosilanized cerium oxide. Step 4: Add 50g of nano-cerium oxide, 2.5g of octadecyltrimethoxysilane, 150g of isopropanol, 9g of deionized water and 0.8g of glacial acetic acid to a reaction flask, stir at 300rpm for 20min, then heat to 68℃ and keep warm for 3h. After the reaction is complete, filter, wash the filter cake twice with 100g of isopropanol, dry at 90℃ for 4h, and then pass through a 200-mesh sieve to obtain octadecylsilanized cerium oxide. Step 5: Take 297g of the polyolefin-compatible heat-resistant and oxygen-resistant aging agent carrier masterbatch obtained in Step 2 and 3g of the aminosilanized cerium oxide obtained in Step 3 and add them to a mixer. Mix them at 118℃ and 60rpm for 10min, then discharge and pelletize to obtain the anti-aging masterbatch. Step Six: First, add 560g of ethylene-vinyl acetate copolymer, 130g of ethylene-octene copolymer, 70g of maleic anhydride grafted polyolefin elastomer, and 260g of anti-aging masterbatch to a mixer and mix at 124℃ and 70rpm for 5 minutes. Then, add 730g of surface-treated magnesium hydroxide and mix for 5 minutes. Next, add 670g of surface-treated magnesium hydroxide, 5g of octadecylsilane-modified cerium oxide, and 10g of zinc stearate and mix at 138℃ and 70rpm for 10 minutes. Finally, reduce the material temperature in the mixer to 118℃, add 6g of dilauryl thiodipropionate and mix for 4 minutes. After discharge, extrude and granulate the material in a twin-screw extruder at conditions of 120℃ in zone 1, 130℃ in zone 2, 140℃ in zone 3, 145℃ in zone 4, and 140℃ at the die head to obtain low-smoke halogen-free heat-resistant flame-retardant environmentally friendly cable material. Step 7: Dry the cable material obtained in Step 6 at 80℃ for 4 hours. Preheat the Category 5 tin-plated annealed copper stranded wire with a nominal cross-section of 35mm² to 60℃. Extrude the protective layer using an extruder. The extrusion temperature is 120℃ in Zone 1, 135℃ in Zone 2, 145℃ in Zone 3, 150℃ in Zone 4, and 155℃ at the die head. The screw speed is 30rpm. The average thickness of the insulation layer is controlled to be 3mm. After cooling in a 25℃ water bath and winding, the cable is treated with an electron beam irradiation crosslinking process with an irradiation dose of 80kGy to obtain a low-smoke halogen-free heat-resistant flame-retardant environmentally friendly cable for new energy storage systems.

[0030] Example 6: Step 1: Add 500g of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid, 630g of glycidyl stearate and 8g of triphenylphosphine to a reactor equipped with a stirrer, thermometer and nitrogen inlet. Start stirring and purge with nitrogen at 22L / h for 30min. Heat the material to 118℃ and react at 130rpm for 3.5h. After the reaction is complete, maintain 118℃ and evacuate to an absolute pressure ≤20kPa for 25min. Then cool down to 82℃ and discharge to obtain a long-chain alkyl-grafted hindered phenol intermediate. Step 2: Take 1000g of maleic anhydride-grafted polyolefin elastomer and dry it at 80℃ for 4h. Add the dried maleic anhydride-grafted polyolefin elastomer, 75g of the long-chain alkyl-grafted hindered phenol intermediate obtained in Step 1 and 5g of zinc stearate to a mixer and mix at 170℃ and 85rpm for 13min. Then, vacuum the mixture to an absolute pressure ≤20kPa and continue mixing for 5min. Discharge and pelletize to obtain polyolefin-compatible heat-oxidative aging agent carrier masterbatch. Step 3: Add 50g of nano-cerium oxide, 2.5g of 3-aminopropyltriethoxysilane, 150g of anhydrous ethanol, 18g of deionized water and 1.2g of glacial acetic acid to a reaction flask, stir at 300rpm for 20min, then heat to 65℃ and keep warm for 2h. After the reaction is complete, filter, wash the filter cake twice with 100g of anhydrous ethanol, dry at 90℃ for 4h, and then pass through a 200-mesh sieve to obtain aminosilanized cerium oxide. Step 4: Add 50g of nano-cerium oxide, 3.5g of octadecyltrimethoxysilane, 150g of isopropanol, 12g of deionized water and 1.2g of glacial acetic acid to a reaction flask, stir at 300rpm for 20min, then heat to 75℃ and keep warm for 3h. After the reaction is complete, filter, wash the filter cake twice with 100g of isopropanol, dry at 90℃ for 4h, and then pass through a 200-mesh sieve to obtain octadecylsilanized cerium oxide. Step 5: Take 290g of the polyolefin-compatible heat-oxidative aging agent carrier masterbatch obtained in Step 2 and 10g of the aminosilanized cerium oxide obtained in Step 3 and add them to a mixer. Mix them at 122℃ and 60rpm for 10min, then discharge and pelletize to obtain the anti-aging masterbatch. Step Six: First, add 510g of ethylene-vinyl acetate copolymer, 170g of ethylene-octene copolymer, 90g of maleic anhydride grafted polyolefin elastomer and 330g of anti-aging masterbatch to a mixer and mix at 126℃ and 70rpm for 5min. Then add 840g of surface-treated magnesium hydroxide and mix for 5min. Next, add 740g of surface-treated magnesium hydroxide, 11g of octadecylsilane cerium oxide and 14g of zinc stearate and mix at 142℃ and 70rpm for 10min. Finally, reduce the material temperature in the mixer to 118℃, add 9g of dilauryl thiodipropionate and mix for 4min. After discharge, extrude and granulate the material in a twin-screw extruder at conditions of 120℃ in zone 1, 130℃ in zone 2, 140℃ in zone 3, 145℃ in zone 4 and 140℃ at the die head to obtain low-smoke halogen-free heat-resistant flame-retardant environmentally friendly cable material. Step 7: Dry the cable material obtained in Step 6 at 80℃ for 4 hours. Preheat the Category 5 tin-plated annealed copper stranded wire with a nominal cross-section of 35mm² to 60℃. Extrude the protective layer using an extruder. The extrusion temperature is 120℃ in Zone 1, 135℃ in Zone 2, 145℃ in Zone 3, 150℃ in Zone 4, and 155℃ at the die head. The screw speed is 30rpm. The average thickness of the insulation layer is controlled to be 3mm. After cooling in a 25℃ water bath and winding, the cable is treated with an electron beam irradiation crosslinking process with an irradiation dose of 80kGy to obtain a low-smoke halogen-free heat-resistant flame-retardant environmentally friendly cable for new energy storage systems.

[0031] Comparative Example 1: The difference from Example 1 is that 60g of the long-chain alkyl-grafted hindered phenol intermediate obtained in Step 1 is not added in Step 2, and the amount of maleic anhydride-grafted polyolefin elastomer in Step 2 is adjusted from 1000g to 1060g. The other conditions are the same as in Example 1.

[0032] Comparative Example 2: The difference from Example 1 is as follows: in step two, 60g of the long-chain alkyl-grafted hindered phenol intermediate obtained in step one is not added; in step five, 277.4g of the polyolefin-compatible heat-oxidative aging agent carrier masterbatch obtained in step two and 6g of the aminosilanized cerium oxide obtained in step three are mixed; in step six, 16.6g of the long-chain alkyl-grafted hindered phenol intermediate obtained in step one is added at the same time when the material is added for the first time; in step six, the amount of anti-aging masterbatch is calculated as 283.4g; and the other conditions are the same as in Example 1.

[0033] Comparative Example 3: The difference from Example 1 is that in step five, 6g of aminosilanized cerium oxide obtained in step three is replaced with 6g of octadecylsilanized cerium oxide obtained in step four, and the other conditions are the same as in Example 1.

[0034] Comparative Example 4: The difference from Example 1 is that in step six, 8g of octadecylsilane cerium oxide obtained in step four is replaced with 8g of aminosilane cerium oxide obtained in step three, and it is added simultaneously with the second batch of surface-treated magnesium hydroxide. The other conditions are the same as in Example 1.

[0035] Comparative Example 5: The difference from Example 1 is that: in step five, 6g of aminosilanized cerium oxide obtained in step three is not added, and the amount of polyolefin-compatible heat-resistant and oxygen-aging agent carrier masterbatch obtained in step two in step five is adjusted from 294g to 300g, while the other conditions are the same as in Example 1.

[0036] Comparative Example 6: The difference from Example 1 is that 8g of the octadecylsilane cerium oxide obtained in Step 4 is not added in Step 6, and the amount of magnesium hydroxide used in the second batch of surface treatment is adjusted from 700g to 708g. The other conditions are the same as in Example 1.

[0037] Comparative Example 7: The difference from Example 1 is that in step six, the two-stage addition of surface-treated magnesium hydroxide is not used. Instead, after the ethylene-vinyl acetate copolymer, ethylene-octene copolymer, maleic anhydride grafted polyolefin elastomer and anti-aging masterbatch are added to the internal mixer and mixed for 5 minutes, 1500g of surface-treated magnesium hydroxide is added at once, followed by 8g of octadecylsilane cerium oxide and 12g of zinc stearate. The remaining conditions are the same as in Example 1.

[0038] Comparative Example 8: The difference from Example 1 is that in step six, dilauryl thiodipropionate is not added after the material temperature in the internal mixer drops to 118°C, but is added simultaneously when the ethylene-vinyl acetate copolymer, ethylene-octene copolymer, maleic anhydride grafted polyolefin elastomer and anti-aging masterbatch are first added to the internal mixer. Dilauryl thiodipropionate is not added in the later stage, and the other conditions are the same as in Example 1.

[0039] Comparative Example 9: The difference from Example 1 is that 8g of dilauryl thiodipropionate is not added in step six, and the amount of maleic anhydride-grafted polyolefin elastomer in step six is ​​adjusted from 80g to 88g, while the other conditions are the same as in Example 1.

[0040] Comparative Example 10: The difference from Example 1 is that in step five, 6g of aminosilanized cerium oxide obtained in step three is replaced with 6g of nano-cerium oxide, and in step six, 8g of octadecylsilanized cerium oxide obtained in step four is replaced with 8g of nano-cerium oxide. The other conditions are the same as in Example 1.

[0041] Performance testing: The low-smoke, halogen-free, heat-resistant, flame-retardant, and environmentally friendly cable materials obtained in Examples 1-6 and Comparative Examples 1-10 were dried in an 80°C forced-air drying oven for 4 hours. A portion of the cable material from each sample was preheated at 150°C for 3 minutes in a flat vulcanizing machine, then hot-pressed at 10 MPa for 8 minutes, followed by cold-pressing at 25°C and 10 MPa for 5 minutes, to produce sheets with thicknesses of 1.0 mm and 3.0 mm, respectively. Both the sheets and the corresponding cable samples underwent electron beam irradiation crosslinking treatment with an irradiation dose of 80 kGy. Another portion of the cable material from each sample was extruded onto a nominal cross-section of 35 mm² using the same extrusion parameters. 2 On Category 5 tin-plated annealed copper stranded wire, the average thickness of the protective layer was controlled at 3 mm. After cooling in a 25°C water bath, winding, and cross-linking by 80 kGy electron beam irradiation, corresponding cable samples were obtained. All sheet and cable samples were placed in an environment of 23±2°C and 50±5% relative humidity for 24 hours before testing.

[0042] Oxidation induction time: The test was conducted according to GB / T 19466.6-2009 "Differential Scanning Calorimetry (DSC) for Plastics - Part 6: Determination of Oxidation Induction Time (Isothermal OIT) and Oxidation Induction Temperature (Dynamic OIT)". Samples of 5.0 ± 0.5 mg were cut from the irradiated cross-linked sheets of Examples 1-6 and Comparative Examples 1-10 and placed in an open aluminum crucible. The temperature was increased to 200 °C at a rate of 20 °C / min under nitrogen flow of 50 mL / min and held for 5 min. Then, oxygen was introduced at a flow rate of 50 mL / min. The time from the switch to oxygen to the exothermic oxidation initiation point was recorded as the oxidation induction time. Each sample was tested in triplicate, and the average value was taken.

[0043] Mechanical retention rate after hot air aging: The test was conducted according to GB / T 2951.11-2008 "General Test Methods for Insulation and Sheath Materials of Cables and Optical Fibers - Part 11: General Test Methods - Thickness and Dimensional Measurement - Mechanical Properties Test" and GB / T2951.12-2008 "General Test Methods for Insulation and Sheath Materials of Cables and Optical Fibers - Part 12: General Test Methods - Thermal Aging Test Method". Cable samples corresponding to Examples 1-6 and Comparative Examples 1-10 were taken, their protective layers were peeled off, and dumbbell-shaped specimens were cut with a thickness of 3.0±0.2 mm. Ten specimens were taken from each sample. Five specimens were placed in an environment of 23±2℃ and 50±5% relative humidity for 24 hours before tensile testing. The other five specimens were placed in a forced-air aging chamber at 180±2℃ for 168 hours, then placed in an environment of 23±2℃ and 50±5% relative humidity for 16 hours before tensile testing. The tensile speed was 250 mm / min. The tensile strength and elongation at break were recorded before and after hot air aging. The tensile strength retention rate and elongation at break retention rate after aging at 180℃ for 168 h were calculated respectively.

[0044] Temperature cycling cracking and insulation resistance: Temperature cycling cracking was tested according to GB / T 2423.22-2012 "Environmental Testing Part 2: Test Methods Test N: Temperature Change". Insulation resistance was tested according to GB / T 3048.5-2007 "Electrical Performance Test Methods for Wires and Cables Part 5: Insulation Resistance Test". Complete cable samples corresponding to Examples 1-6 and Comparative Examples 1-10 were taken. Ten 10m lengths of cable were cut from each sample, bent and fixed on a cylindrical mandrel with a diameter of 120mm, and placed in a temperature cycling chamber. The cycling conditions were: -40℃ for 1 hour, temperature increased to 150℃ at 5℃ / min, held at 150℃ for 1 hour, and then decreased to -40℃ at 5℃ / min. This process constituted one cycle, and 200 cycles were performed continuously. After the cycle was completed, the cable was placed at 23±2℃ for 4 hours. The surface cracks of the protective layer were inspected with the naked eye and a 10x magnifying glass, and the number of cracks per 10m of cable was recorded. Then the cable sample was immersed in water at 20±2℃ for 24 hours, a DC voltage of 500V was applied, the insulation resistance was read at 1 minute and converted to the insulation resistance constant at 20℃.

[0045] Oxygen index and single-strand vertical burning performance: The oxygen index was tested according to GB / T 2406.2-2009 "Determination of burning behavior by oxygen index method for plastics - Part 2: Room temperature test". 3.0 mm irradiated cross-linked sheets from Examples 1-6 and Comparative Examples 1-10 were cut into 80 mm × 10 mm × 3 mm specimens. Five specimens were tested for each sample, and the average oxygen index was recorded. Single-strand vertical burning performance was tested according to GB / T 18380.12-2022 "Burn test of cables and optical fibers under flame conditions - Part 12: Vertical flame propagation test of single insulated wires and cables - 1 kW premixed flame test method". Complete cable samples corresponding to Examples 1-6 and Comparative Examples 1-10 were taken. Three cables of 600 mm in length were cut from each sample, the specimens were fixed according to the standard, and a 1 kW premixed flame was applied. The charring distance was recorded after combustion.

[0046] Smoke density and combustion gas acidity: Smoke density was tested according to GB / T 17651.2-2021 "Determination of smoke density of cables or optical fibers under specific conditions - Part 2: Test procedures and requirements". Complete cable samples corresponding to Examples 1-6 and Comparative Examples 1-10 were taken, and three sets of cables of specified length were cut from each sample. These were placed in a smoke density test chamber for combustion, and the minimum light transmittance during the test was recorded. Combustion gas acidity was tested according to GB / T 17650.2-2021 "Test methods for gases released during combustion of materials derived from cables or optical fibers - Part 2: Determination of acidity (measured by pH) and conductivity". Corresponding cable protective layer material was taken, shredded, and mixed thoroughly. 1000 mg of the sample was weighed and placed in a combustion boat, burned in a specified tubular furnace, and the combustion gases were absorbed. The pH value of the absorption liquid was tested.

[0047] Table 1 Performance Test Results

[0048] As shown in Table 1, Comparative Example 1 did not introduce a long-chain alkyl-grafted hindered phenol intermediate. Although its oxygen index was still 36.8% and its minimum transmittance was 77.6%, which can reflect the low-smoke flame retardancy of the high-filled magnesium hydroxide system, its oxidation induction time at 200℃ was only 19.4 min. After aging in hot air at 180℃ for 168 h, the retention rates of tensile strength and elongation at break were 45.8% and 31.6%, respectively. After thermal cycling, the number of cracks reached 10.4 per 10 m. This indicates that it is difficult to achieve both long-term thermo-oxidative stability and thermal cycling stability by relying solely on inorganic flame retardants and downstream thioesters.

[0049] In Comparative Example 2, the long-chain alkyl-grafted hindered phenol intermediate was directly added to the total mixing stage, increasing the oxidation induction time to 37.5 min, but lower than the 53.6 min in Example 1. This indicates that the carrier treatment is beneficial to improving the effective role of the thermo-oxidative aging protection unit in the polyolefin phase.

[0050] Comparative Examples 3 to 6, by changing the positioning method of aminosilanized cerium oxide, octadecylsilanized cerium oxide, or one of the cerium oxides, respectively, showed that the oxidation induction time, elongation retention after aging, number of thermal cycling cracks, and insulation resistance constant were all lower than those of Example 1 to varying degrees. This indicates that the segmented addition of the two surface morphologies of cerium oxide is not a simple substitution relationship, but rather has a synergistic effect on the antioxidant properties of the resin phase and the stability of the filler interface.

[0051] Comparative Example 7, which did not use magnesium hydroxide added in two stages, showed that the carbonization distance increased to 189 mm, the minimum light transmittance decreased to 71.8%, and the number of thermal cycling cracks was 7.4 per 10 m. This indicates that the timing of adding flame-retardant fillers affects the carbonization integrity and thermal cycling stability of the finished cable after combustion.

[0052] Comparative Example 8 added dilauryl thiodipropionate in advance, while Comparative Example 9 did not add the thioester. The oxidation induction times for both were 45.0 min and 39.4 min, respectively, both lower than those for Example 1. This indicates that adding the thioester at a lower temperature in the later stage is more conducive to preserving its hydroperoxide decomposition effect during service.

[0053] Comparative Example 10, which uses unmodified nano-cerium oxide, has a thermal cycling crack number of 8.2 cracks / 10m and an insulation resistance constant of 4418.65 MΩ·km at 20℃, which is lower than the examples using two types of silanized cerium oxide. This indicates that the surface morphology of cerium oxide has a significant impact on the stability of the system.

[0054] Examples 1 to 6 maintained good low-smoke halogen-free flame retardant properties within the range of oxygen index 35.6%-39.4%, minimum light transmittance 76.8%-84.1%, and combustion gas pH 6.12-6.48. Among them, the oxidation induction time of Example 6 reached 64.7 min, and the tensile strength retention rate and elongation at break retention rate after aging at 180℃ for 168 h reached 86.5% and 78.6%, respectively. The number of cracks after thermal cycling was only 0.3 per 10 m, and the insulation resistance constant at 20℃ reached 9075.40 MΩ·km.

[0055] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity.

Claims

1. A low-smoke, halogen-free, heat-resistant, flame-retardant, and environmentally friendly cable for new energy storage systems, characterized in that... It includes a conductor and an insulating protective layer covering the outer surface of the conductor, wherein the insulating protective layer is prepared from low-smoke halogen-free heat-resistant flame-retardant environmentally friendly cable material for new energy storage systems; By weight, the low-smoke halogen-free heat-resistant flame-retardant environmentally friendly cable material is prepared from the following raw materials: 480-560 parts ethylene-vinyl acetate copolymer, 130-200 parts ethylene-octene copolymer, 70-100 parts maleic anhydride grafted polyolefin elastomer, 260-340 parts anti-aging masterbatch, 1400-1600 parts surface-treated magnesium hydroxide, 5-12 parts octadecylsilane-modified cerium oxide, 10-15 parts zinc stearate, and 6-10 parts dilaurate thiodipropionate. The surface-treated magnesium hydroxide includes a first part of surface-treated magnesium hydroxide and a second part of surface-treated magnesium hydroxide. The preparation method of the low-smoke halogen-free heat-resistant flame-retardant environmentally friendly cable for the new energy storage system includes the following steps: (1) Preparation of long-chain alkyl-grafted hindered phenol intermediates, which are obtained by reacting 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid with C16-C22 long-chain fatty acid glycidyl esters; (2) Maleic anhydride-grafted polyolefin elastomer, the long-chain alkyl-grafted hindered phenol intermediate and zinc stearate are mixed to obtain polyolefin-compatible heat-oxidative aging agent carrier masterbatch. (3) Prepare aminosilanized cerium oxide and octadecylsilanized cerium oxide respectively; (4) The polyolefin-compatible heat-resistant and oxygen-resistant aging agent carrier masterbatch and aminosilanized cerium oxide are mixed to obtain an anti-aging masterbatch; (5) First, add 480-560 parts of ethylene-vinyl acetate copolymer, 130-200 parts of ethylene-octene copolymer, 70-100 parts of maleic anhydride grafted polyolefin elastomer and 260-340 parts of anti-aging masterbatch to a mixer and mix at 124-126℃ and 70rpm for 5min; then add 730-850 parts of the first part of surface-treated magnesium hydroxide and mix for 5min; then add 670-750 parts of the second part of surface-treated magnesium hydroxide, 5-12 parts of octadecylsilane cerium oxide and 10-15 parts of zinc stearate and mix at 138-142℃ and 70rpm for 10min; finally, reduce the temperature of the material in the mixer to 118℃, add 6-10 parts of dilauryl thiodipropionate and mix for 4min, and after discharge, extrude and granulate in a twin-screw extruder to obtain low-smoke halogen-free heat-resistant flame-retardant environmentally friendly cable material; (6) Dry the low-smoke halogen-free heat-resistant flame-retardant environmentally friendly cable material at 80°C for 4 hours, preheat the conductor to 60°C, and use an extruder to extrude the cable material onto the outer surface of the conductor to form an insulating protective layer. After cooling in a water tank and winding, use an electron beam irradiation crosslinking process with an irradiation dose of 80 kGy to obtain a low-smoke halogen-free heat-resistant flame-retardant environmentally friendly cable for new energy storage systems.

2. The low-smoke, halogen-free, heat-resistant, flame-retardant, and environmentally friendly cable for new energy storage systems according to claim 1, characterized in that, The anti-aging masterbatch is obtained by mixing and pelletizing 288-297 parts of polyolefin-compatible heat-resistant and oxygen-resistant aging agent carrier masterbatch and 3-12 parts of aminosilanized cerium oxide.

3. The low-smoke, halogen-free, heat-resistant, flame-retardant, and environmentally friendly cable for new energy storage systems according to claim 1, characterized in that, The polyolefin-compatible heat-oxidative aging agent carrier masterbatch is obtained by mixing and pelletizing 1000 parts of maleic anhydride-grafted polyolefin elastomer, 50-75 parts of long-chain alkyl-grafted hindered phenol intermediate, and 3-5 parts of zinc stearate.

4. The low-smoke, halogen-free, heat-resistant, flame-retardant, and environmentally friendly cable for new energy storage systems according to claim 1, characterized in that, The long-chain alkyl-grafted hindered phenolic intermediate is obtained by reacting 500 parts of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid, 586-739 parts of C16-C22 long-chain fatty acid glycidyl esters, and 4-8 parts of triphenylphosphine.

5. The low-smoke, halogen-free, heat-resistant, flame-retardant, and environmentally friendly cable for new energy storage systems according to claim 1, characterized in that, The C16-C22 long-chain fatty acid glycidyl esters are glycidyl palmitate, glycidyl stearate, glycidyl eicosanoate, or glycidyl dodecanoate.

6. The low-smoke, halogen-free, heat-resistant, flame-retardant, and environmentally friendly cable for new energy storage systems according to claim 1, characterized in that, The aminosilanized cerium oxide is obtained by reacting 50 parts of nano-cerium oxide, 1.5-2.5 parts of 3-aminopropyltriethoxysilane, 150 parts of anhydrous ethanol, 12-18 parts of deionized water and 0.8-1.2 parts of glacial acetic acid.

7. The low-smoke, halogen-free, heat-resistant, flame-retardant, and environmentally friendly cable for new energy storage systems according to claim 1, characterized in that, The octadecylsilane-modified cerium oxide is obtained by reacting 50 parts of nano-cerium oxide, 2.5-3.5 parts of octadecyltrimethoxysilane, 150 parts of isopropanol, 9-12 parts of deionized water and 0.8-1.2 parts of glacial acetic acid.

8. The low-smoke, halogen-free, heat-resistant, flame-retardant, and environmentally friendly cable for new energy storage systems according to claim 1, characterized in that, The vinyl acetate content of the ethylene-vinyl acetate copolymer is 30wt%-35wt%, and the melt flow rate at 190℃ and 2.16kg is 0.1-0.3g / 10min; the melt flow rate of the ethylene-octene copolymer at 190℃ and 2.16kg is 0.4-0.6g / 10min.

9. A method for preparing a low-smoke, halogen-free, heat-resistant, flame-retardant, and environmentally friendly cable for a new energy storage system according to any one of claims 1-8, characterized in that, Includes the following steps: (1) Preparation of long-chain alkyl-grafted hindered phenol intermediates, which are obtained by reacting 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid with C16-C22 long-chain fatty acid glycidyl esters; (2) Maleic anhydride-grafted polyolefin elastomer, the long-chain alkyl-grafted hindered phenol intermediate and zinc stearate are mixed to obtain polyolefin-compatible heat-oxidative aging agent carrier masterbatch. (3) Prepare aminosilanized cerium oxide and octadecylsilanized cerium oxide respectively; (4) The polyolefin-compatible heat-resistant and oxygen-resistant aging agent carrier masterbatch and aminosilanized cerium oxide are mixed to obtain an anti-aging masterbatch; (5) First, add 480-560 parts of ethylene-vinyl acetate copolymer, 130-200 parts of ethylene-octene copolymer, 70-100 parts of maleic anhydride grafted polyolefin elastomer and 260-340 parts of anti-aging masterbatch to a mixer and mix at 124-126℃ and 70rpm for 5min; then add 730-850 parts of the first part of surface-treated magnesium hydroxide and mix for 5min; then add 670-750 parts of the second part of surface-treated magnesium hydroxide, 5-12 parts of octadecylsilane cerium oxide and 10-15 parts of zinc stearate and mix at 138-142℃ and 70rpm for 10min; finally, reduce the temperature of the material in the mixer to 118℃, add 6-10 parts of dilauryl thiodipropionate and mix for 4min, and after discharge, extrude and granulate in a twin-screw extruder to obtain low-smoke halogen-free heat-resistant flame-retardant environmentally friendly cable material; (6) Dry the low-smoke halogen-free heat-resistant flame-retardant environmentally friendly cable material at 80°C for 4 hours, preheat the conductor to 60°C, and use an extruder to extrude the cable material onto the outer surface of the conductor to form an insulating protective layer. After cooling in a water tank and winding, use an electron beam irradiation crosslinking process with an irradiation dose of 80 kGy to obtain a low-smoke halogen-free heat-resistant flame-retardant environmentally friendly cable for new energy storage systems.

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