High-temperature-resistant high-power cable for new energy charging pile and preparation method of high-temperature-resistant high-power cable

Abstract

The invention discloses a high-temperature-resistant high-power cable for a new energy charging pile and a preparation method of the high-temperature-resistant high-power cable, and belongs to the technical field of cable processing. The high-temperature-resistant high-power cable for the new energy charging pile is used for solving the technical problem that in the prior art, the flame retardance, the wear resistance, the high-temperature resistance, the mechanical strength and the toughness of the high-temperature-resistant high-power cable for the new energy charging pile need to be further improved, and specifically comprises a cable core bundle, an insulating layer, a filling layer, a wrapping layer and an outer sheath layer. And the outer sheath layer comprises the following components in parts by weight: 65-75 parts of a polyurethane elastomer, 3-6 parts of modified nano magnesium oxide, 10-15 parts of a reinforcing agent, 5-10 parts of polyacrylic acid isooctyl powder and 3-4 parts of an auxiliary additive. The flame retardant property, wear resistance, high temperature resistance, mechanical strength and toughness of the cable are improved through the polyurethane elastomer, the modified nano magnesium oxide, the reinforcing agent and the poly (isooctyl acrylate) powder.

Description

Technical Field

[0001] This invention relates to the field of cable processing technology, specifically to a high-temperature resistant high-power cable for new energy charging piles and its preparation method. Background Technology

[0002] With the rapid development of the new energy vehicle industry, charging piles are being upgraded towards high power and fast charging. The supporting cables need to withstand the high temperature load brought by high current for a long time, and at the same time face complex working conditions such as outdoor friction, bending installation, and fire risk. This places stringent requirements on the high temperature resistance, flame retardancy, wear resistance and toughness of the cable outer sheath.

[0003] Currently, the outer sheath of charging pile cables is mostly made of polyvinyl chloride, ordinary polyurethane, or single modified elastomer materials. However, their comprehensive performance still needs to be further improved. In summer, the cables are used in hot environments for a long time, and the outer sheath material is prone to thermo-oxidative degradation, resulting in a decrease in tensile strength and a decrease in elongation at break, which affects the service life of the cable. At the same time, single flame retardants lack the synergistic effect of gas phase and condensed phase, making it difficult to meet the high flame retardant requirements of charging pile scenarios. Ordinary commercially available fillers have poor dispersion in elastomers, and traditional nano-inorganic fillers have dense hydroxyl groups on their surface, which have poor compatibility with organic matrices and are prone to agglomeration to form structural defects, which not only reduces the wear resistance of the material but also causes fluctuations in mechanical properties. In addition, some materials sacrifice flexibility in pursuit of high temperature resistance, which makes them prone to cracking when bent or under stress, affecting the safety of installation and use.

[0004] To address this technical deficiency, a solution is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a high-temperature resistant high-power cable for new energy charging piles and its preparation method, which solves the technical problem that the flame retardant performance, wear resistance, high temperature resistance, mechanical strength and toughness of high-temperature resistant high-power cables for new energy charging piles need to be further improved in the prior art.

[0006] The objective of this invention can be achieved through the following technical solution: a high-power cable with high temperature resistance for new energy charging piles, comprising a cable core bundle, an insulation layer, a filling layer, a wrapping layer, and an outer sheath layer;

[0007] The cable outer sheath layer comprises the following components by weight: 65-75 parts polyurethane elastomer, 15-25 parts filler and 3-4 parts auxiliary additives;

[0008] The filler comprises the following components by weight: 3-6 parts modified nano magnesium oxide, 10-15 parts reinforcing agent and 5-10 parts polyisooctyl acrylate powder.

[0009] Furthermore, the preparation method of the polyurethane elastomer is as follows: polytetrahydrofuran ether diol, dihydrazide terephthalate, ether solution, isophorone diisocyanate and dibutyltin dilaurate are added to a reaction vessel containing N,N-dimethylacetamide. After stirring under a nitrogen atmosphere at 30-40°C for 3-4 hours, the temperature is raised to 60-70°C and stirring is continued for 10-12 hours. After the reaction is completed, the product is transferred to a reaction vessel containing 3-4L of cyclohexane, stirred for 10-20 minutes, aged for 2-3 hours, filtered, and the filter cake is washed 3-5 times with deionized water. Then it is transferred to a vacuum drying oven and dried to constant weight under vacuum conditions at 80°C to obtain the polyurethane elastomer.

[0010] Reaction mechanism:

[0011]

[0012] In the formula:

[0013]

[0014] Under a nitrogen atmosphere and catalysis by dibutyltin dilaurate, the isocyanate group in the isophorone diisocyanate molecule undergoes a nucleophilic addition reaction with the hydroxyl group in polytetrahydrofuran ether diol, the amino group in terephthalic acid dihydrazide, and the amino group in 4,4'-diaminodiphenyl disulfide, gradually polymerizing to form a polyurethane with free isocyanate group end caps.

[0015] Furthermore, the ether solution is obtained by dissolving 1.2 g of 4,4'-diaminodiphenyl disulfide in 30 mL of N,N-dimethylacetamide; the ratio of the amount of polytetrahydrofuran ether diol, terephthalic acid dihydrazide, ether solution, dibutyltin dilaurate, and N,N-dimethylacetamide is 30 g: 1.9 g: 30 mL: 0.1-0.2 g: 30-40 mL; the ratio of the amount of isophorone diisocyanate is 0.55 times the total molar amount of hydroxyl groups in polytetrahydrofuran ether diol to the total molar amount of amino groups in terephthalic acid dihydrazide and the ether solution.

[0016] Furthermore, the modified nano-magnesium oxide is prepared by the following steps:

[0017] A1. Add nano-magnesium oxide to a reaction vessel containing anhydrous ethanol, and ultrasonically disperse it at 40-50℃ for 20-30 min. Add silane coupling agent solution dropwise, stir for 40-60 min, and after the reaction is completed, filter it. Place the product in a vacuum drying oven and dry it at 80℃ to constant weight. Grind it and pass it through a 200-mesh sieve to obtain pretreated nano-magnesium oxide.

[0018] A2. Spread the pretreated nano-magnesium oxide evenly on the surface of the dielectric plate of the plasma fluorination device. After evacuating the vacuum reaction chamber, fill it with mixed gas and repeat 2-3 times. Turn on the plasma discharge power supply, adjust the output frequency to 8-9kHz, fluorinate for 20-30 minutes, and then turn off the power supply to obtain modified nano-magnesium oxide.

[0019] Reaction mechanism:

[0020] The hydroxyl groups on the surface of nano-magnesium oxide remain active in anhydrous ethanol. In an aqueous ethanol solution, the silane coupling agent KH560 undergoes hydrolysis. The hydrolysis products and the hydroxyl groups on the surface of nano-magnesium oxide form Si-O-Mg covalent bonds through dehydration condensation, allowing KH560 to be firmly grafted onto the surface of nano-magnesium oxide. Subsequently, under the plasma action of a mixture of CF4 and N2 gas, CF4 is dissociated into fluorine-containing active species such as F· radicals and CF3· radicals. N2 maintains plasma stability and inhibits excessive decomposition. These active species undergo substitution reactions with hydrogen atoms on the silane segments of KH560 to form CF bonds. At the same time, some F· radicals react with the residual hydroxyl groups on the surface of nano-magnesium oxide to generate Mg-F bonds, ultimately yielding modified nano-magnesium oxide with silane segment anchoring and fluorine-containing group modification.

[0021] Further, in step A1, the ratio of the amount of nano-magnesium oxide, anhydrous ethanol, and silane coupling agent solution is 10g:50-60mL:8-9mL, and the silane coupling agent solution is obtained by uniformly mixing 5g KH560 with 40-45mL of 85wt% ethanol aqueous solution; in step A2, the mixed gas is obtained by mixing CF4 and N2 at a volume ratio of 25:1.

[0022] Furthermore, the preparation method of the reinforcing agent is as follows: Under a nitrogen atmosphere, DOPO acrylate monomer is added to a reaction vessel containing butyl acetate, the temperature is raised to 30-40℃, and the mixture is stirred for 10-20 min. Then, (diethoxyphosphoryl)methacrylate is added and the mixture is stirred for another 5-10 min. Then, an initiator is added, the temperature is raised to 100-110℃, and the mixture is stirred for 6-8 h. After the reaction is completed, the mixture is cooled to 30-40℃, and the product is transferred to a rotary evaporator. The product is then rotary evaporated at 80-100℃ and -0.09 MPa for 2-3 h. Finally, the product is transferred to a vacuum drying oven and dried at 70-80℃ for 4-5 h. The product is then ground and passed through a 200-mesh sieve to obtain the reinforcing agent.

[0023] Reaction mechanism:

[0024]

[0025] Dicumyl peroxide undergoes thermal decomposition, generating primary free radicals that attack the acrylate double bonds in the DOPO acrylate monomer and (diethoxyphosphoryl)methacrylate molecules, causing the double bonds to open and forming an active free radical intermediate. Subsequently, the active free radicals of the two monomers form a random copolymer of repeating acrylate units through a chain growth reaction. Finally, after rotary evaporation to remove the solvent, drying, and grinding, a reinforcing agent that combines gas-phase-condensed-phase synergistic flame retardancy with a balance of strength and toughness is obtained.

[0026] Furthermore, the ratio of DOPO acrylate monomer, butyl acetate, (diethoxyphosphoryl)methacrylate and initiator is 30-32g:22g:60-65mL:0.4-0.5g, and the initiator is dicumyl peroxide.

[0027] Furthermore, the preparation method of the polyisooctyl acrylate powder is as follows: sodium dodecyl sulfate is added to a reaction vessel containing deionized water, the temperature is raised to 40-50℃ and stirred for 20-30 minutes, then isooctyl acrylate and potassium persulfate aqueous solution are added, the temperature is raised to 70-80℃ and stirred for 3-4 hours under a nitrogen atmosphere. After the reaction is completed, 10wt% sodium hydroxide solution is added dropwise to adjust the pH of the solution to 6.5-7.5, the product is transferred to a porcelain dish, placed in a vacuum drying oven at 60-70℃, dried to constant weight, ground, and passed through a 200-mesh sieve to obtain polyisooctyl acrylate powder; the ratio of sodium dodecyl sulfate, deionized water, isooctyl acrylate and potassium persulfate aqueous solution is 1.2g:180-190mL:100g:10mL, and the mass fraction of the potassium persulfate aqueous solution is 4.8%.

[0028] Reaction mechanism:

[0029] Sodium dodecyl sulfate dissolves in deionized water to form micelles, which encapsulate hydrophobic isooctyl acrylate monomers, forming a stable oil-water emulsion system. Under heating conditions, potassium persulfate undergoes thermal decomposition to generate primary free radicals. These primary free radicals diffuse into the micelles and rapidly attack and open the carbon-carbon double bonds in the isooctyl acrylate molecules, forming active free radical intermediates. Subsequently, the active free radicals continuously initiate the monomers within the micelles through a chain growth reaction, causing the double bonds to open continuously and be orderly incorporated into the polymer growth chain, gradually forming a polyisooctyl acrylate macromolecular chain. Finally, the micelles are transformed into stable latex particles loaded with the polymer, and the polymerization reaction is completed. After post-processing, polyisooctyl acrylate powder is obtained.

[0030] This invention also proposes a method for preparing a high-temperature resistant, high-power cable for new energy charging piles, comprising the following steps:

[0031] S1. Several cable cores are arranged in parallel, and an insulation layer is used to cover the outside of the cable cores to form an insulation layer on the outside of the cable cores. Then, three bundles of cable cores covered by the insulation layer are arranged in parallel, and filler rope is filled in the gaps between the cable core bundles to form a filler layer. Wrapping tape is used to wrap the parallel cable core bundles and the filler layer together to form a wrapping layer on the outside of the cable core bundles and the wrapping layer.

[0032] S2. Add polyurethane elastomer, filler and auxiliary additives to a high-speed mixer and stir for 5-10 minutes. Then transfer the mixture to a twin-screw extruder for melt blending for 5-8 minutes. Extrude and coat the outside of the wrapping layer. The coated cable is first cooled in air for 20-30 seconds, then placed in a cooling water bath at 20-30℃ for 3-5 minutes. After removal, it is dried with hot air for 1-2 minutes and then wound up to obtain a high-power cable with high temperature resistance.

[0033] Further, in step S1, the cable core includes a conductor, an insulation layer, a filler layer, and a wrapping layer arranged sequentially from the inside out. The conductor is a copper alloy, the insulation layer is obtained by wrapping the cable core with cross-linked polyethylene, the filler rope is a dust-free rock wool rope, and the wrapping layer is obtained by wrapping mica tape around the cable core and the filler layer. In step S2, the temperature of the six temperature zones set from the feed end to the die head of the twin-screw extruder is set sequentially to 170℃, 175℃, 180℃, 180℃, 175℃, and 175℃, and the spindle speed of the twin-screw extruder is 15-25 r / min.

[0034] The present invention has the following beneficial effects:

[0035] 1. The reinforcing agent of this invention contains phosphorus and has a copolymer structure, which can exert a synergistic flame-retardant effect between the gas phase and the condensed phase, effectively inhibiting the advancement of the combustion reaction. Modified nano-magnesium oxide, as an inorganic phase, has both excellent thermal stability and interfacial compatibility. Its surface silane segments and fluorine-containing groups not only strengthen the bonding with the polyurethane elastomer matrix, but also form a physical barrier layer to block heat transfer and oxygen penetration, thus synergistically improving the flame-retardant effect with the reinforcing agent. The cross-linked structure of the polyurethane elastomer gives the matrix good thermal stability, while the flexible structure of polyisooctyl acrylate powder can alleviate thermal stress at high temperatures and reduce structural damage during thermal aging. The synergistic effect of multiple factors enables the cable to maintain structural stability for a long time in high-temperature environments and resist thermo-oxidative degradation.

[0036] 2. The polyurethane elastomer of this invention possesses excellent elastic characteristics, and its cross-linked structure provides basic mechanical support for the cable. The isooctyl polyacrylate powder, as a flexible dispersed phase, can absorb impact energy in the matrix, alleviate stress concentration, and effectively improve the material's ductility. The modified nano-magnesium oxide, after being modified by silane coupling agent and plasma fluorination, is uniformly dispersed and tightly bonded to the matrix interface, avoiding the mechanical defects caused by the easy agglomeration of unmodified fillers, and instead enhancing the overall structural integrity. The copolymer segments of the reinforcing agent can form entanglement with the polyurethane elastomer matrix, further optimizing mechanical stability. The multiple synergistic effects enable the cable to maintain sufficient strength and exhibit good elongation performance when under stress, while also possessing sufficient toughness during cable bending.

[0037] 3. The modified nano-magnesium oxide of this invention, as a high-hardness inorganic filler, has silane segments and fluorine-containing groups on its surface that enhance its compatibility with the polyurethane elastomer matrix, ensuring its uniform dispersion in the matrix and forming a stable reinforcing network. This significantly improves the surface hardness and structural density of the cable outer sheath. The copolymer structure of the reinforcing agent improves the overall coherence of the matrix, reduces component shedding during wear, and provides solid structural support for the crosslinking structure of the polyurethane elastomer. The isooctyl acrylate powder improves the interfacial bonding state, reducing local wear caused by stress concentration. The synergistic effect of all components effectively resists damage to the cable outer sheath from external friction, extending the cable's service life. Detailed Implementation

[0038] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. 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.

[0039] In this application, polytetrahydrofuran ether diol is selected from Nantong Yuanrong Chemical Co., Ltd., CAS No. 25190-06-1, PTMEG1000;

[0040] In this application, the nano-magnesium oxide is selected from Sichuan High Purity Materials Technology Co., Ltd., with CAS number 1309-48-4 and a specification of 50nm;

[0041] In this application, DOPO acrylate monomer has CAS number 167307-26-8.

[0042] Example 1

[0043] This embodiment provides a method for preparing polyurethane elastomer and modified nano-magnesium oxide, including the following steps:

[0044] S1. Preparation of polyurethane elastomer

[0045] Weigh out 12g of 4,4'-diaminodiphenyl disulfide and dissolve it in 300mL of N,N-dimethylacetamide to obtain an ether solution;

[0046] Weigh out 300g of polytetrahydrofuran ether diol, 19g of terephthalic acid dihydrazide, 300mL of ether solution, calculate the amount of isophorone diisocyanate to be added based on 0.55 times the total molar amount of hydroxyl groups in polytetrahydrofuran ether diol and the total molar amount of amino groups in terephthalic acid dihydrazide and ether solution, and add 1g of dibutyltin dilaurate to a reactor containing 300mL of N,N-dimethylacetamide. Stir for 3h at 30℃ under a nitrogen atmosphere, then raise the temperature to 60℃ and continue stirring for 10h. After the reaction is completed, transfer the product to a reactor containing 3L of cyclohexane, stir for 10min, age for 2h, filter, wash the filter cake 3 times with deionized water, and then transfer it to a vacuum drying oven and dry to constant weight under vacuum at 80℃ to obtain polyurethane elastomer.

[0047] S2, Preparation of modified nano-magnesium oxide

[0048] Weigh out 10g of KH560 and mix it with 80mL of 85wt% ethanol aqueous solution to obtain a silane coupling agent solution.

[0049] Weigh 100g of nano-magnesium oxide and add it to a reaction vessel containing 500mL of anhydrous ethanol. Disperse it ultrasonically at 40℃ for 20min. Add 80mL of silane coupling agent solution dropwise and stir for 40min. After the reaction is complete, filter the mixture and place it in a vacuum drying oven. Dry it at 80℃ to constant weight, grind it, and pass it through a 200-mesh sieve to obtain pretreated nano-magnesium oxide.

[0050] Pretreated nano-magnesium oxide was spread on the surface of the dielectric plate of the plasma fluorination device. After the vacuum reaction chamber was evacuated, it was filled with a gas obtained by mixing CF4 and N2 in a volume ratio of 25:1. This process was repeated twice. The plasma discharge power supply was turned on, the output frequency was adjusted to 8kHz, and the fluorination treatment was carried out for 20 minutes. The power supply was then turned off to obtain modified nano-magnesium oxide.

[0051] Example 2

[0052] This embodiment provides a method for preparing polyurethane elastomer and modified nano-magnesium oxide, including the following steps:

[0053] S1. Preparation of polyurethane elastomer

[0054] Weigh out 12g of 4,4'-diaminodiphenyl disulfide and dissolve it in 300mL of N,N-dimethylacetamide to obtain an ether solution;

[0055] Weigh out 300g of polytetrahydrofuran ether diol, 19g of terephthalic acid dihydrazide, 300mL of ether solution, calculate the amount of isophorone diisocyanate to be added based on 0.55 times the total molar amount of hydroxyl groups in polytetrahydrofuran ether diol and the total molar amount of amino groups in terephthalic acid dihydrazide and ether solution, and add 1.5g of dibutyltin dilaurate to a reactor containing 350mL of N,N-dimethylacetamide. Stir at 35℃ under a nitrogen atmosphere for 3.5h, then raise the temperature to 65℃ and continue stirring for 11h. After the reaction is complete, transfer the product to a reactor containing 3.5L of cyclohexane, stir for 15min, age for 2.5h, filter, wash the filter cake 4 times with deionized water, and then transfer it to a vacuum drying oven and dry it to constant weight under vacuum at 80℃ to obtain polyurethane elastomer.

[0056] S2, Preparation of modified nano-magnesium oxide

[0057] Weigh out 10g of KH560 and mix it thoroughly with 85mL of 85wt% ethanol aqueous solution to obtain a silane coupling agent solution;

[0058] Weigh 100g of nano-magnesium oxide and add it to a reaction vessel containing 550mL of anhydrous ethanol. Disperse it ultrasonically at 45℃ for 25min. Add 85mL of silane coupling agent solution dropwise and stir for 45min. After the reaction is complete, filter the mixture and place it in a vacuum drying oven. Dry it at 80℃ to constant weight, grind it, and pass it through a 200-mesh sieve to obtain pretreated nano-magnesium oxide.

[0059] Pretreated nano-magnesium oxide was spread on the surface of the dielectric plate of the plasma fluorination device. After the vacuum reaction chamber was evacuated, it was filled with a gas obtained by mixing CF4 and N2 in a volume ratio of 25:1. This process was repeated twice. The plasma discharge power supply was turned on, the output frequency was adjusted to 8kHz, and the fluorination treatment was carried out for 25 minutes. The power supply was then turned off to obtain modified nano-magnesium oxide.

[0060] Example 3

[0061] This embodiment provides a method for preparing polyurethane elastomer and modified nano-magnesium oxide, including the following steps:

[0062] S1. Preparation of polyurethane elastomer

[0063] Weigh out 12g of 4,4'-diaminodiphenyl disulfide and dissolve it in 300mL of N,N-dimethylacetamide to obtain an ether solution;

[0064] Weigh out 300g of polytetrahydrofuran ether diol, 19g of terephthalic acid dihydrazide, 300mL of ether solution, calculate the amount of isophorone diisocyanate to be added based on 0.55 times the total molar amount of hydroxyl groups in polytetrahydrofuran ether diol and the total molar amount of amino groups in terephthalic acid dihydrazide and ether solution, and add 2g of dibutyltin dilaurate to a reactor containing 400mL of N,N-dimethylacetamide. Stir at 40℃ under a nitrogen atmosphere for 4h, then raise the temperature to 70℃ and continue stirring for 12h. After the reaction is completed, transfer the product to a reactor containing 4L of cyclohexane, stir for 20min, age for 3h, filter, wash the filter cake 5 times with deionized water, and then transfer it to a vacuum drying oven and dry it to constant weight under vacuum at 80℃ to obtain polyurethane elastomer.

[0065] S2, Preparation of modified nano-magnesium oxide

[0066] Weigh out 10g of KH560 and mix it thoroughly with 90mL of 85wt% ethanol aqueous solution to obtain a silane coupling agent solution;

[0067] Weigh 100g of nano-magnesium oxide and add it to a reaction vessel containing 600mL of anhydrous ethanol. Disperse it ultrasonically at 50℃ for 30min. Add 90mL of silane coupling agent solution dropwise and stir for 60min. After the reaction is complete, filter the mixture and place it in a vacuum drying oven. Dry it at 80℃ to constant weight, grind it, and pass it through a 200-mesh sieve to obtain pretreated nano-magnesium oxide.

[0068] Pretreated nano-magnesium oxide was spread on the surface of the dielectric plate of the plasma fluorination device. After the vacuum reaction chamber was evacuated, it was filled with a gas obtained by mixing CF4 and N2 in a volume ratio of 25:1. This process was repeated 3 times. The plasma discharge power supply was turned on, the output frequency was adjusted to 9kHz, and the fluorination treatment was carried out for 30 minutes. The power supply was then turned off to obtain modified nano-magnesium oxide.

[0069] Example 4

[0070] This embodiment provides a method for preparing a reinforcing agent and isooctyl acrylate powder, including the following steps:

[0071] Step 1: Preparation of reinforcing agent

[0072] Under a nitrogen atmosphere, 300g of DOPO acrylate monomer was weighed and added to a reactor containing 220g of butyl acetate. The mixture was heated to 30°C and stirred for 10 minutes. Then, 600mL of (diethoxyphosphoryl) methacrylate was added and stirred for another 5 minutes. Finally, 4g of initiator dicumyl peroxide was added, and the mixture was heated to 100°C and stirred for 6 hours. After the reaction was completed, the mixture was cooled to 30°C and the product was transferred to a rotary evaporator. The product was then rotary evaporated at 80°C and -0.09MPa for 2 hours. After that, the product was transferred to a vacuum drying oven and dried at 70°C for 4 hours. The product was then ground and passed through a 200-mesh sieve to obtain the reinforcing agent.

[0073] Step 2: Preparation of polyisooctyl acrylate powder

[0074] Weigh 12g of sodium dodecyl sulfate and add it to a reaction vessel containing 1.8L of deionized water. Heat the mixture to 40℃ and stir for 20min. Then add 1kg of isooctyl acrylate and 100mL of 4.8wt% potassium persulfate aqueous solution. Heat the mixture to 70℃ and stir for 3h under a nitrogen atmosphere. After the reaction is complete, add 10wt% sodium hydroxide solution dropwise to adjust the pH of the solution to 6.5. Transfer the product to a porcelain dish and place it in a vacuum drying oven at 60℃. Dry the product to constant weight, grind it, and pass it through a 200-mesh sieve to obtain isooctyl acrylate powder.

[0075] Example 5

[0076] This embodiment provides a method for preparing a reinforcing agent and isooctyl acrylate powder, including the following steps:

[0077] Step 1: Preparation of reinforcing agent

[0078] Under a nitrogen atmosphere, 310g of DOPO acrylate monomer was weighed and added to a reactor containing 220g of butyl acetate. The mixture was heated to 35℃ and stirred for 15min. Then, 620mL of (diethoxyphosphoryl) methacrylate was added and the mixture was stirred for another 8min. Finally, 4.5g of initiator dicumyl peroxide was added, and the mixture was heated to 105℃ and stirred for 7h. After the reaction was completed, the mixture was cooled to 35℃ and the product was transferred to a rotary evaporator. The product was rotary evaporated at 90℃ and -0.09MPa for 2.5h, and then transferred to a vacuum drying oven and dried at 75℃ for 4.5h. The product was then ground and passed through a 200-mesh sieve to obtain the reinforcing agent.

[0079] Step 2: Preparation of polyisooctyl acrylate powder

[0080] Weigh 12g of sodium dodecyl sulfate and add it to a reaction vessel containing 1.8L of deionized water. Heat the mixture to 45℃ and stir for 25min. Then add 1kg of isooctyl acrylate and 100mL of 4.8wt% potassium persulfate aqueous solution. Heat the mixture to 75℃ and stir for 3.5h under a nitrogen atmosphere. After the reaction is complete, add 10wt% sodium hydroxide solution dropwise to adjust the pH of the solution to 7.0. Transfer the product to a porcelain dish and place it in a vacuum drying oven at 65℃. Dry the product to constant weight, grind it, and pass it through a 200-mesh sieve to obtain isooctyl acrylate powder.

[0081] Example 6

[0082] This embodiment provides a method for preparing a reinforcing agent and isooctyl acrylate powder, including the following steps:

[0083] Step 1: Preparation of reinforcing agent

[0084] Under a nitrogen atmosphere, 320g of DOPO acrylate monomer was weighed and added to a reactor containing 220g of butyl acetate. The mixture was heated to 40℃ and stirred for 20min. Then, 650mL of (diethoxyphosphoryl) methacrylate was added and stirred for another 10min. Finally, 5g of initiator dicumyl peroxide was added, and the mixture was heated to 110℃ and stirred for 8h. After the reaction was completed, the mixture was cooled to 40℃ and the product was transferred to a rotary evaporator. The product was then rotary evaporated at 100℃ and -0.09MPa for 3h. After that, the product was transferred to a vacuum drying oven and dried at 80℃ for 5h. The product was then ground and passed through a 200-mesh sieve to obtain the reinforcing agent.

[0085] Step 2: Preparation of polyisooctyl acrylate powder

[0086] Weigh 12g of sodium dodecyl sulfate and add it to a reaction vessel containing 1.9L of deionized water. Heat the mixture to 50℃ and stir for 30min. Then add 1kg of isooctyl acrylate and 100mL of 4.8wt% potassium persulfate aqueous solution. Heat the mixture to 80℃ and stir for 4h under a nitrogen atmosphere. After the reaction is complete, add 10wt% sodium hydroxide solution dropwise to adjust the pH of the solution to 7.5. Transfer the product to a porcelain dish and place it in a vacuum drying oven at 70℃. Dry the product to constant weight, grind it, and pass it through a 200-mesh sieve to obtain isooctyl acrylate powder.

[0087] Example 7

[0088] This embodiment provides a method for preparing a high-temperature resistant, high-power cable for new energy charging piles, including the following steps:

[0089] Step 1: Conductor Forming

[0090] Copper alloy is selected as the conductor. Several cable cores are arranged in parallel. Cross-linked polyethylene is extruded and wrapped around the outside of the cable cores to form an insulation layer. Then, three bundles of cable cores wrapped with cross-linked polyethylene insulation are arranged in parallel. Dust-filled rock wool rope is placed in the gaps between the cable core bundles to form a filling layer. Mica wrapping tape is used to wrap the parallel cable core bundles and the filling layer together to form a wrapping layer on the outside of the cable core bundles and the wrapping layer.

[0091] Step 2: Add an outer sheath layer

[0092] By weight, 65 parts of polyurethane elastomer and 3 parts of modified nano-magnesium oxide prepared in Example 1, 10 parts of reinforcing agent and 5 parts of polyisooctyl acrylate powder prepared in Example 4, and 3 parts of auxiliary additives were added to a high-speed mixer and stirred for 5 minutes. The mixture was then transferred to a twin-screw extruder. The twin-screw extruder had 6 temperature zones set from the feed end toward the die head, with temperatures of 170°C, 175°C, 180°C, 180°C, 175°C, and 175°C respectively. The spindle speed of the twin-screw extruder was 15 r / min. After melt blending for 5 minutes, the mixture was extruded and coated onto the outside of the wrapping layer. The coated cable was first cooled in air for 20 seconds, then cooled in a 20°C cooling water bath for 3 minutes. After removal, it was dried with hot air for 1 minute and then wound up to obtain a high-power cable resistant to high temperatures.

[0093] Example 8

[0094] This embodiment provides a method for preparing a high-temperature resistant, high-power cable for new energy charging piles, including the following steps:

[0095] Step 1: Conductor Forming

[0096] Copper alloy is selected as the conductor. Several cable cores are arranged in parallel. Cross-linked polyethylene is extruded and wrapped around the outside of the cable cores to form an insulation layer. Then, three bundles of cable cores wrapped with cross-linked polyethylene insulation are arranged in parallel. Dust-filled rock wool rope is placed in the gaps between the cable core bundles to form a filling layer. Mica wrapping tape is used to wrap the parallel cable core bundles and the filling layer together to form a wrapping layer on the outside of the cable core bundles and the wrapping layer.

[0097] Step 2: Add an outer sheath layer

[0098] By weight, 70 parts of polyurethane elastomer and 4 parts of modified nano-magnesium oxide prepared in Example 2, 12 parts of reinforcing agent and 8 parts of polyisooctyl acrylate powder prepared in Example 5, and 3 parts of auxiliary additives were added to a high-speed mixer and stirred for 8 minutes. The mixture was then transferred to a twin-screw extruder. The twin-screw extruder had 6 temperature zones set from the feed end toward the die head, with temperatures of 170°C, 175°C, 180°C, 180°C, 175°C, and 175°C respectively. The spindle speed of the twin-screw extruder was 20 r / min. After melt blending for 6 minutes, the mixture was extruded and coated onto the outside of the wrapping layer. The coated cable was first cooled in air for 25 seconds, then cooled in a 25°C cooling water bath for 4 minutes. After removal, it was dried with hot air for 1 minute and then wound up to obtain a high-temperature resistant high-power cable.

[0099] Example 6

[0100] This embodiment provides a method for preparing a high-temperature resistant, high-power cable for new energy charging piles, including the following steps:

[0101] Step 1: Conductor Forming

[0102] Copper alloy is selected as the conductor. Several cable cores are arranged in parallel. Cross-linked polyethylene is extruded and wrapped around the outside of the cable cores to form an insulation layer. Then, three bundles of cable cores wrapped with cross-linked polyethylene insulation are arranged in parallel. Dust-filled rock wool rope is placed in the gaps between the cable core bundles to form a filling layer. Mica wrapping tape is used to wrap the parallel cable core bundles and the filling layer together to form a wrapping layer on the outside of the cable core bundles and the wrapping layer.

[0103] Step 2: Add an outer sheath layer

[0104] By weight, 75 parts of polyurethane elastomer and 6 parts of modified nano-magnesium oxide prepared in Example 3, 15 parts of reinforcing agent and 10 parts of isooctyl acrylate powder prepared in Example 6, and 4 parts of auxiliary additives were added to a high-speed mixer and stirred for 10 minutes. The mixture was then transferred to a twin-screw extruder. The twin-screw extruder had six temperature zones set from the feed end toward the die head, with temperatures of 170°C, 175°C, 180°C, 180°C, 175°C, and 175°C respectively. The spindle speed of the twin-screw extruder was 25 r / min. After melt blending for 8 minutes, the mixture was extruded and coated onto the outside of the wrapping layer. The coated cable was first cooled in air for 30 seconds, then cooled in a 30°C cooling water bath for 5 minutes. After removal, it was dried with hot air for 2 minutes and then wound up to obtain a high-temperature resistant high-power cable.

[0105] Comparative Example 1

[0106] The difference between this comparative example and Example 9 is that step S2 in Example 3 is omitted, and the modified nano-magnesium oxide in Example 9 is replaced with nano-magnesium oxide in step S2.

[0107] Comparative Example 2

[0108] The difference between this comparative example and Example 9 is that step (1) in Example 6 is omitted, and the reinforcing agent in Example 9 is replaced with (diethoxyphosphoryl)methacrylate in step (1).

[0109] Comparative Example 3

[0110] The difference between this comparative example and Example 9 is that step (2) in Example 6 is omitted, and polyisooctyl acrylate powder is not added in Example 6.

[0111] Performance testing:

[0112] The fire resistance ratings of the high-temperature resistant high-power cables prepared in Examples 7-9 and Comparative Examples 1-3 were determined in accordance with the standard XF 535-2005 "Flame-retardant and fire-resistant cables - classification and requirements for flame-retardant rubber-insulated cables".

[0113] The mass wear of the high-temperature resistant high-power cables prepared in Examples 7-9 and Comparative Examples 1-3 was determined according to the standard QB / T 5101-2017 "Test Method for Abrasion Resistance of Plastic Pipes".

[0114] The tensile strength and elongation at break of the high-temperature resistant high-power cables prepared in Examples 7-9 and Comparative Examples 1-3 were determined in accordance with the standard 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 Measurements - Mechanical Properties Tests".

[0115] Referring to standard GB / T 2951.12-2008 "General Test Methods for Insulation and Sheath Materials of Cables and Optical Fibers - Part 12: General Test Methods - Thermal Aging Test Method", samples of high-temperature resistant high-power cables prepared in Examples 7-9 and Comparative Examples 1-3 were placed in an air oven and aged at 80-100℃ for 7 days. The performance of the aged cables was then measured. The specific test results are shown in Table 1 below:

[0116] Table 1 - Performance Test Data of Samples

[0117]

[0118] Data Analysis:

[0119] Comparative analysis of the data in Table 1 above shows that the high-power cable with high temperature resistance prepared by this invention has the following characteristics before thermal aging: its fire resistance rating is A, its mass wear is 0.059g, its tensile strength is 23.1MPa, and its elongation at break is 452%. After thermal aging, its fire resistance rating is A, its mass wear is 0.069g, its tensile strength is 20.1MPa, and its elongation at break is 393%.

[0120] In Comparative Example 1, the hydroxyl groups on the surface of unmodified nano-magnesium oxide are dense and prone to agglomeration, resulting in extremely poor compatibility with the polyurethane elastomer matrix. This makes it impossible to form a uniformly dispersed reinforcing network, which not only causes defects in the outer sheath structure and makes the agglomerates easy to fall off during wear, increasing the mass wear amount to 0.092g, but also leads to stress concentration, reducing the tensile strength and elongation at break to 16.5MPa and 329%, respectively. At the same time, the agglomerates destroy the continuity of the physical barrier layer, making it easy for oxygen to penetrate and difficult for heat to conduct, which reduces the flame retardant performance and thermal aging stability. The retention rate of tensile strength and elongation at break after thermal aging is significantly reduced.

[0121] In Comparative Example 2, the single monomer cannot form copolymer segments containing DOPO structure, lacking the synergistic flame retardant effect of gas phase-condensed phase, and can only exert a limited flame retardant effect of condensed phase, causing the flame retardant rating to drop to Class C. In addition, there is no entanglement between the copolymer segments and the polyurethane elastomer matrix, resulting in poor matrix mechanical stability and interfacial coherence. It cannot effectively support tensile strength and elongation at break, nor can it reduce component shedding during wear, ultimately leading to a decrease in tensile strength, elongation at break and wear resistance to 18.8 MPa, 368% and 0.087 g, respectively.

[0122] In Comparative Example 3, the absence of isooctyl acrylate powder as a flexible dispersed phase caused the outer sheath to lose its key support for absorbing impact energy and alleviating stress concentration, resulting in a decrease in elongation at break to 371%. The cable's toughness was insufficient when bent and under stress, and the interfacial bonding state was not optimized, increasing the risk of local wear and raising the mass wear amount to 0.082g. During thermal aging, due to the lack of a flexible phase to alleviate thermal stress, the elongation at break decreased to 345%, further highlighting the important role of this powder in toughness and auxiliary wear resistance and heat aging resistance.

[0123] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A high-temperature resistant, high-power cable for new energy charging piles, characterized in that, This includes the cable core bundle, insulation layer, filler layer, wrapping layer, and outer sheath layer; The cable outer sheath layer comprises the following components by weight: 65-75 parts polyurethane elastomer, 20-30 parts filler and 3-4 parts auxiliary additives; The filler comprises the following components by weight: 3-6 parts modified nano magnesium oxide, 10-15 parts reinforcing agent and 5-10 parts polyisooctyl acrylate powder.

2. The high-temperature resistant high-power cable for new energy charging piles according to claim 1, characterized in that, The preparation method of the polyurethane elastomer is as follows: polytetrahydrofuran ether diol, diterephthalic acid dihydrazide, ether solution, isophorone diisocyanate and dibutyltin dilaurate are added to a reaction vessel containing N,N-dimethylacetamide, stirred for 3-4 hours under a nitrogen atmosphere at 30-40°C, then heated to 60-70°C and stirred for another 10-12 hours, followed by post-treatment to obtain the polyurethane elastomer.

3. The high-temperature resistant high-power cable for new energy charging piles according to claim 2, characterized in that, The ether solution was obtained by dissolving 1.2 g of 4,4'-diaminodiphenyl disulfide in 30 mL of N,N-dimethylacetamide; the ratio of the amount of polytetrahydrofuran ether diol, terephthalic acid dihydrazide, ether solution, dibutyltin dilaurate, and N,N-dimethylacetamide was 30 g: 1.9 g: 30 mL: 0.1-0.2 g: 30-40 mL; the ratio of the amount of isophorone diisocyanate was 0.55 times the total molar amount of hydroxyl groups in polytetrahydrofuran ether diol to the total molar amount of amino groups in terephthalic acid dihydrazide and the ether solution.

4. The high-temperature resistant high-power cable for new energy charging piles according to claim 1, characterized in that, The modified nano-magnesium oxide was prepared by the following steps: A1. Add nano-magnesium oxide to a reaction vessel containing anhydrous ethanol, ultrasonically disperse it at 40-50℃ for 20-30 min, add silane coupling agent solution dropwise, stir for 40-60 min, and then perform post-treatment to obtain pretreated nano-magnesium oxide. A2. Spread the pretreated nano-magnesium oxide evenly on the surface of the dielectric plate of the plasma fluorination device. After evacuating the vacuum reaction chamber, fill it with mixed gas and repeat 2-3 times. Turn on the plasma discharge power supply, adjust the output frequency to 8-9kHz, fluorinate for 20-30 minutes, and then turn off the power supply to obtain modified nano-magnesium oxide.

5. A high-temperature resistant, high-power cable for new energy charging piles according to claim 4, characterized in that, In step A1, the ratio of the amount of nano-magnesium oxide, anhydrous ethanol, and silane coupling agent solution is 10g:50-60mL:8-9mL, and the silane coupling agent solution is obtained by uniformly mixing 5g KH560 with 40-45mL of 85wt% ethanol aqueous solution; in step A2, the mixed gas is obtained by mixing CF4 and N2 at a volume ratio of 25:

1.

6. The high-temperature resistant high-power cable for new energy charging piles according to claim 1, characterized in that, The preparation method of the reinforcing agent is as follows: Under a nitrogen atmosphere, DOPO acrylate monomer is added to a reaction vessel containing butyl acetate, the temperature is raised to 30-40℃, and the mixture is stirred for 10-20 min. Then, (diethoxyphosphoryl)methacrylate is added and the mixture is stirred for another 5-10 min. Finally, an initiator is added, the temperature is raised to 100-110℃, and the mixture is stirred for 6-8 h. After post-treatment, the reinforcing agent is obtained.

7. A high-temperature resistant, high-power cable for new energy charging piles according to claim 6, characterized in that, The ratio of DOPO acrylate monomer, butyl acetate, (diethoxyphosphoryl)methacrylate and initiator is 30-32g:22g:60-65mL:0.4-0.5g, and the initiator is dicumyl peroxide.

8. A high-temperature resistant, high-power cable for new energy charging piles according to claim 1, characterized in that, The preparation method of the polyisooctyl acrylate powder is as follows: sodium dodecyl sulfate is added to a reaction vessel containing deionized water, the temperature is raised to 40-50℃ and stirred for 20-30 min, then isooctyl acrylate and potassium persulfate aqueous solution are added, the temperature is raised to 70-80℃ and stirred for 3-4 h under a nitrogen atmosphere, and then post-treated to obtain polyisooctyl acrylate powder; the ratio of sodium dodecyl sulfate, deionized water, isooctyl acrylate and potassium persulfate aqueous solution is 1.2 g: 180-190 mL: 100 g: 10 mL, and the mass fraction of potassium persulfate aqueous solution is 4.8%.

9. A method for preparing a high-temperature resistant, high-power cable for new energy charging piles according to any one of claims 1-8, characterized in that, Includes the following steps: S1. Several cable cores are arranged in parallel, and an insulation layer is used to cover the outside of the cable cores to form an insulation layer on the outside of the cable cores. Then, three bundles of cable cores covered by the insulation layer are arranged in parallel, and filler rope is filled in the gaps between the cable core bundles to form a filler layer. Wrapping tape is used to wrap the parallel cable core bundles and the filler layer together to form a wrapping layer on the outside of the cable core bundles and the wrapping layer. S2. Add polyurethane elastomer, filler and auxiliary additives to a high-speed mixer and stir for 5-10 minutes. Then transfer the mixture to a twin-screw extruder for melt blending for 5-8 minutes. Extrude and coat the outside of the wrapping layer. The coated cable is first cooled in air for 20-30 seconds, then placed in a cooling water bath at 20-30℃ for 3-5 minutes. After removal, it is dried with hot air for 1-2 minutes and then wound up to obtain a high-power cable with high temperature resistance.

10. A method for preparing a high-temperature resistant, high-power cable for a new energy charging pile according to claim 9, characterized in that, In step S1, the cable core includes a conductor, an insulation layer, a filler layer, and a wrapping layer arranged sequentially from the inside out. The conductor is a copper alloy, the insulation layer is obtained by wrapping the cable core with cross-linked polyethylene, the filler rope is a dust-free rock wool rope, and the wrapping layer is obtained by wrapping mica tape around the cable core and the filler layer. In step S2, the temperature of the six temperature zones set from the feed end to the die head of the twin-screw extruder is set sequentially to 170℃, 175℃, 180℃, 180℃, 175℃, and 175℃, and the spindle speed of the twin-screw extruder is 15-25 r / min.

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