High-flexibility weather-proof cable material for new energy electric vehicle

Abstract

The invention discloses a high-flexibility weather-resistant cable material for a new energy electric vehicle, belongs to the technical field of cable material preparation, and is used for solving the technical problem that the flexibility and weather resistance of a cable material for a new energy electric vehicle in the prior art need to be further improved. The cable specifically comprises a plurality of cable cores, a wrapping layer and a sheath layer which are sequentially arranged from inside to outside. According to the invention, silanol and a titanium source react under an alkali catalysis condition to construct a Si-O-Ti structure, a compact silicon dioxide layer is generated on the surface of titanium dioxide in situ to form core-shell type composite particles, a silane coupling agent containing amino is further introduced to realize organic functionalization of the surfaces of the particles, and isocyanate reacts with flexible diol to prepare the flexible polyurethane composite particles. The preparation method comprises the following steps: synthesizing a modified flexibilizer containing a triazole structure, reacting the modified flexibilizer with hydroxyl silicone oil to form hydroxyl-terminated polyurethane, and introducing a phosphate cross-linked structure through phosphoryl chloride, thereby obtaining the high-performance cable outer sheath material.

Description

Technical Field

[0001] The present invention relates to the technical field of cable material preparation, and in particular to a highly flexible and weather-resistant cable material for new energy electric vehicles. Background Art

[0002] With the rapid development of new energy vehicles, the high-voltage system of the whole vehicle has put forward higher requirements on the comprehensive performance of cable materials, especially in terms of flexibility and weather resistance. Traditional cable sheath materials are prone to aging, hardening or cracking in complex environments such as long-term high temperature, strong ultraviolet rays, and low temperature, affecting the safety of vehicle operation.

[0003] In recent years, flexible materials have gradually developed from thermoplastic elastomers to high-molecular-weight modified polymers to meet the needs of bending performance and dynamic fatigue performance in complex wiring environments. At the same time, weather resistance technology has also continued to improve. By introducing anti-UV, antioxidant, and thermally stable components, the service life of cable materials can be effectively extended, providing material guarantees for the stable operation of new energy electric vehicles.

[0004] Currently, cable sheath material solutions still have certain limitations in balancing flexibility and weather resistance. On the one hand, to improve material flexibility, large amounts of plasticizers or low-modulus elastic components are often added. Although initially soft, this can easily lead to high-temperature migration, decreased mechanical strength, and poor long-term stability. Fatigue cracking is particularly common after repeated bending in confined spaces. On the other hand, enhancing weather resistance often relies on the addition of external antioxidants or UV absorbers, which gradually lose their effectiveness over time and are unable to withstand the test of long-term, multi-climate operating conditions. Although some inorganic fillers can improve heat resistance, their poor interfacial compatibility can easily lead to stress concentration, affecting the synergistic performance of the overall material.

[0005] Therefore, the existing solutions still have a lot of room for optimization in terms of material microstructure design, component synergistic stability and processing technology consistency. Summary of the Invention

[0006] The purpose of the present invention is to provide a highly flexible and weather-resistant cable material for new energy electric vehicles, which is used to solve the technical problem in the prior art that the flexibility and weather resistance of cable materials for new energy electric vehicles need to be further improved.

[0007] The object of the present invention can be achieved by the following technical solution: A highly flexible weather-resistant cable material for new energy electric vehicles, comprising a cable core, a wrapping layer and a sheath layer arranged in sequence from the inside out;

[0008] The cable core is made of polyvinyl chloride melt-extruded and coated on the surface of the copper conductor; the wrapping layer is made of copper tape wrapped around the cable core surface; the outer sheath layer is made of composite polyurethane melt-extruded material, coated on the cable core surface and solidified;

[0009] The composite polyurethane material comprises the following raw materials in parts by weight: 80-100 parts of composite polyurethane, 1-2 parts of antioxidant, 1-2 parts of lubricant and 5-8 parts of plasticizer;

[0010] Furthermore, the antioxidant is one or both of N,N'-diphenyl-p-phenylenediamine and distearyl thiodipropionate; the lubricant is one or more of oleic acid, calcium stearate and polyethylene wax; and the plasticizer is one or more of dibutyl phthalate, dioctyl sebacate and dioctyl adipate.

[0011] Furthermore, the preparation method of the cable core is as follows: adding polyvinyl chloride into a twin-screw extruder, wherein the temperatures of the eight temperature sections of the twin-screw extruder from the feed port toward the discharge port are 150°C, 155°C, 160°C, 160°C, 165°C, 165°C, 170°C, and 170°C, respectively, the main engine speed of the twin-screw extruder is 80-120rpm, and the pressure is 100-150bar, melt-extruding and coating the surface of the copper wire, and curing to obtain the cable core;

[0012] Furthermore, the preparation method of the sheath layer is as follows: adding composite polyurethane, antioxidant, lubricant and plasticizer into a twin-screw extruder, the temperatures of the eight temperature sections of the twin-screw extruder from the feed port to the discharge port are 170°C, 175°C, 190°C, 190°C, 195°C, 195°C, 200°C and 200°C, the main engine speed of the twin-screw extruder is 80-120rpm, the pressure is 100-150bar, melt extrusion is applied to the surface of the cable core, and the sheath layer is obtained after curing;

[0013] Furthermore, the diameter of the copper conductor in the cable core is 0.4 mm, the thickness of the polyvinyl fluoride coating is 0.6 mm, the thickness of the wrapping layer is 0.3 mm, and the thickness of the outer sheath layer is 1.5 mm.

[0014] The preparation method of composite polyurethane comprises the following steps: adding modified polyurethane, triethylamine and N,N-dimethylformamide into a reactor, introducing nitrogen for protection, lowering the temperature of the reactor to 0-5°C, and dropwise adding a calculated amount of phosphorus oxychloride into the reactor, after the dropwise addition is completed within 10-15 minutes, gradually raising the temperature of the reactor to room temperature, keeping the temperature for reaction for 2 hours, and post-processing to obtain composite polyurethane.

[0015] The reaction principle for preparing composite polyurethane is as follows: through the selective reaction of phosphorus oxychloride with hydroxyl groups, phosphate groups are introduced between polyurethane molecular chains to achieve intermolecular cross-linking, and in the presence of triethylamine, the hydrochloric acid byproduct generated during the reaction is effectively neutralized, promoting the reaction to proceed in the direction of forming a phosphate structure, thereby preparing composite polyurethane.

[0016] Furthermore, in the process of preparing the composite polyurethane, the amount ratio of modified polyurethane, triethylamine and N,N-dimethylformamide is 8-10g:1-2g:80-100mL, and the amount of phosphorus oxychloride is 0.25-0.30 times the molar amount of hydroxyl groups in the reaction system. The post-treatment includes: after the reaction is completed, the temperature of the reactor is lowered to room temperature, the reaction liquid is transferred to a rotary evaporator at a temperature of 100°C, and reduced pressure distillation is performed until no liquid is extracted to obtain the composite polyurethane.

[0017] Furthermore, the preparation method of the modified polyurethane includes the following steps: adding hydroxy silicone oil, N,N-dimethylformamide and dibutyltin dilaurate to a reactor, introducing nitrogen protection, adding a calculated amount of 1,6-hexamethylene diisocyanate to the reactor, raising the temperature of the reactor to 50-60°C, keeping the temperature for reaction for 1-2 hours, continuing to add a modified flexibilizer to the reactor, and post-treating to obtain the modified polyurethane.

[0018] The reaction principle for preparing modified polyurethane is as follows: with the participation of catalyst dibutyltin dilaurate and solvent, hydroxy silicone oil first undergoes addition reaction with isocyanate, and the hydroxyl group and isocyanate group form a stable carbamate bond to realize the initial construction of the polyurethane chain. By controlling the amount of reactants, an intermediate structure terminated with isocyanate group is obtained. Subsequently, a modified flexibilizer is introduced to continue reacting with residual isocyanate to adjust the flexibility and mechanical properties of the molecular chain, improve the ductility and compatibility of the material, and thus obtain a hydroxyl-terminated modified polyurethane.

[0019] Furthermore, the dosage ratio of hydroxy silicone oil, N,N-dimethylformamide, dibutyltin dilaurate and modified flexibilizer is 8-10g:30-36mL:0.3-0.5g:1g, wherein the dosage of isophorone diisocyanate is 0.55-0.60 times the molar amount of hydroxyl groups in the reaction system. The post-treatment includes: after the reaction is completed, the temperature of the reactor is lowered to room temperature, the reaction liquid is transferred to a rotary evaporator at a temperature of 100°C, and distilled under reduced pressure until no liquid is extracted to obtain a modified polyurethane.

[0020] Furthermore, the preparation method of the modified flexibilizer comprises the following steps:

[0021] A1. Add the modified microparticles and N,N-dimethylformamide to a reactor and stir. After nitrogen protection, add the calculated amount of 1,6-hexamethylene diisocyanate to the reactor and stir at room temperature for 30-40 minutes to obtain a modified solution.

[0022] A2. Under nitrogen protection, the modified liquid and dibutyltin dilaurate were added to the reactor and stirred. After the temperature of the reactor was raised to 50-60°C, the calculated amount of polyethylene glycol and N-[(4-methyl-1H-benzotriazole-1-yl)methyl]diethanolamine were added to the reactor. After the reaction was kept warm for 2-4 hours, the modified flexibilizer was obtained by post-treatment.

[0023] The reaction principle for preparing the modified flexible agent is as follows: 1,6-hexamethylene diisocyanate undergoes an addition reaction with the amino functional group introduced on the surface of the modified particles under appropriate solvent and nitrogen protection conditions, and an isocyanate group-terminated intermediate is obtained by controlling the amount of reactants. Then, polyethylene glycol with a hydroxyl functional group and a triazole diol compound containing a heterocyclic structure are introduced. Under the action of a catalyst, the isocyanate group further undergoes a typical polyurethane-type condensation reaction with the hydroxyl group to form a structurally stable carbamate bond. In this process, the introduction of the triazole ring not only improves the product's anti-aging and UV stability, but also gives it potential free radical capture or antioxidant capabilities, thereby significantly enhancing the multifunctional synergy of the modified flexible agent, and a hydroxyl-terminated modified flexible agent is obtained by controlling the amount of reactants.

[0024] Furthermore, in step A1, the ratio of the modified microparticles to N,N-dimethylformamide is 1 g:10-12 mL, wherein the amount of 1,6-hexamethylene diisocyanate is 0.60-0.65 times the molar amount of amino groups in the reaction system;

[0025] Furthermore, in step A2, the amount ratio of the modified liquid and dibutyltin dilaurate is 10-12mL:0.03g, wherein the amount of polyethylene glycol is 0.55-0.65 times the isocyanate group in the reaction system, and the amount of N-[(4-methyl-1H-benzotriazole-1-yl)methyl]diethanolamine is 0.10-0.15 times the isocyanate group in the reaction system. The post-treatment includes: after the reaction is completed, the temperature of the reactor is lowered to room temperature, the reaction liquid is transferred to a rotary evaporator at a temperature of 100°C, and distilled under reduced pressure until no liquid is extracted to obtain a modified flexible agent.

[0026] Furthermore, the preparation method of the modified microparticles comprises the following steps:

[0027] B1. Add the nano-titanium dioxide dispersion into a reactor and stir. Use saturated sodium hydroxide to adjust the pH of the reaction system to 9-10. Then, add the ethyl orthosilicate dispersion dropwise into the reactor within 10-15 minutes and stir at room temperature for 4-5 hours. Post-treat to obtain composite particles.

[0028] B2. Add the composite microparticles, anhydrous ethanol and deionized water into a reactor and stir. After the temperature of the reactor is raised to 40-60°C, use saturated sodium hydroxide to adjust the pH of the reaction system to 9-10, add 3-aminopropyltrimethoxysilane into the reactor, keep warm and stir for 2-4 hours, and post-treat to obtain modified microparticles.

[0029] The reaction principle for preparing modified microparticles is as follows: through the hydrolysis and polycondensation of silanols under alkaline catalysis, an inorganic hybrid bonding structure represented by Si-O-Ti is formed, so that a dense and stable silica layer is formed in situ on the surface of the titanium dioxide particles, thereby obtaining a core-shell inorganic composite structure. In this process, the sol-gel system realizes the coating and stabilization of the particle surface through a condensation reaction at the molecular level, effectively improving the dispersion and interface control ability of the microparticles; on this basis, by introducing silane coupling molecules with organic functional groups, the hydrolyzable silane groups are further utilized to undergo covalent polycondensation reaction with the hydroxyl groups on the surface of the microparticles to generate stable Si-O-Si or Si-O-Ti connecting bonds, thereby realizing the introduction of organic functional site amino groups on the surface of the inorganic structure, and finally preparing modified microparticles.

[0030] Furthermore, in step B1, the amount ratio of the nano-titanium dioxide dispersion and the ethyl orthosilicate dispersion is 80-100 mL:5-6 mL, wherein the nano-titanium dioxide dispersion is obtained by mixing nano-titanium dioxide, anhydrous ethanol and deionized water in an amount ratio of 1-2 g:80 mL:20 mL, and the ethyl orthosilicate dispersion is obtained by mixing methyl orthosilicate and anhydrous ethanol in an amount ratio of 0.6-0.8 mL:5-6 mL. The post-treatment includes: after the reaction is completed, the temperature of the reactor is lowered to room temperature, the reaction original is filtered and the filter cake is collected and washed with anhydrous ethanol and deionized water 3-5 times, and then the filter cake is transferred to a drying oven at a temperature of 80°C and vacuum dried to room temperature to obtain composite particles;

[0031] Furthermore, in step B2, the amount ratio of the composite particles, anhydrous ethanol, deionized water and 3-aminopropyltrimethoxysilane is 1g:20-30mL:10mL:0.3g, and the post-treatment includes: after the reaction is completed, the temperature of the reactor is lowered to room temperature, the reaction mixture is filtered to collect the filter cake and the filter cake is washed 3-5 times with anhydrous ethanol and deionized water, and then the filter cake is transferred to a drying oven at a temperature of 80°C and vacuum dried to room temperature to obtain modified particles.

[0032] The present invention has the following beneficial effects:

[0033] 1. This scheme achieves synergistic optimization of the flexibility and wear resistance of weather-resistant cable materials by introducing flexible siloxane segments and TiO2@SiO2 core-shell structured particles. The siloxane segments impart excellent flexibility and low-temperature deformation recovery to the polyurethane matrix, while improving the overall stress distribution of the material and reducing the risk of fracture. The SiO2 shell in the TiO2@SiO2 particles has good surface lubricity and hardness, and can form a microscopic support structure on the polymer surface, enhancing scratch resistance and wear resistance. The uniform distribution of particles in the matrix not only effectively suppresses the defects caused by the easy agglomeration of traditional inorganic fillers, but also improves the interfacial adhesion and stress transfer efficiency through the interfacial interaction with the siloxane segments. At the same time, the chain extension effect increases the hydrogen bond density and structural regularity between the molecular chains, thereby enhancing the material's wear resistance and reducing the risk of surface damage, thereby significantly enhancing the mechanical stability and durability of the weather-resistant cable material without sacrificing flexibility.

[0034] 2. This solution shows significant advantages in improving the material's resistance to ultraviolet aging. The key lies in the synergistic cooperation between the TiO2@SiO2 core-shell structure particles, the surface-modified benzotriazole structure and the siloxane-type polyurethane matrix. Among them, the TiO2 core gives the material excellent ultraviolet shielding ability, and the SiO2 shell effectively isolates its photocatalytic activity, preventing polymer degradation caused by free radical generation. Further, by introducing benzotriazole-type ultraviolet absorption groups to modify the particle surface, it not only enhances the selective absorption and stability of ultraviolet light, but also improves the interfacial affinity between the particles and the organic matrix, effectively improving the dispersibility and photostability synergy. The siloxane segment in the polyurethane main chain has good weather resistance and flexibility, and can slowly release the structural damage caused by photo-oxidative aging. Finally, the multiple structures are used to synergize at the molecular level to form a stable ultraviolet protection network, which significantly improves the long-term stability and durability of the material under ultraviolet radiation.

[0035] 3. This scheme also achieves efficient synergy between inorganic particles and siloxane polyurethane matrix by constructing TiO2@SiO2 core-shell structure particles and introducing phosphorus oxychloride cross-linking system, thereby significantly improving the flame retardant properties of weather-resistant cable materials. The phosphate ester structure introduced by phosphorus oxychloride can form polyphosphoric acid during pyrolysis, promote the formation of carbon layer and play a role in heat insulation and oxygen isolation; TiO2@SiO2 particles generate stable and dense inorganic residues during combustion, further enhancing the thermal barrier effect and inhibiting the release of combustible gas and heat diffusion. At the same time, the functional groups on the particle surface have good compatibility with the siloxane chain segments, which helps to uniformly disperse the particles and stabilize the interface, thereby improving the synergistic flame retardant efficiency. Finally, the organic-inorganic integrated design not only ensures the flame retardant efficiency but also takes into account the flexibility and stability of the weather-resistant cable material. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0037] Figure 1 It is a schematic diagram of the overall three-dimensional structure of the present invention.

[0038] In the figure: 1. Cable core; 2. Wrapping layer; 3. Sheath layer. DETAILED DESCRIPTION

[0039] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0040] In this application, the hydroxy silicone oil used was purchased from Zhejiang Zhenghe Silicon Materials Co., Ltd. with the brand number 207-35; the nano titanium dioxide used was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. with the product number T104943; the polyethylene glycol used was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. with the product number P615522; and the polyethylene wax used was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. with the product number P903666.

[0041] Example 1

[0042] This embodiment provides a method for preparing a modified flexibilizer for preparing a highly flexible and weather-resistant cable material for new energy electric vehicles, comprising the following steps:

[0043] Step ①: Preparation of composite microparticles

[0044] Weigh: 10.0 g of nano-titanium dioxide, 800.0 mL of anhydrous ethanol, and 200.0 mL of deionized water to mix to obtain a nano-titanium dioxide dispersion;

[0045] Weigh 6.0 mL of methyl orthosilicate and 50.0 mL of anhydrous ethanol and mix to obtain a ethyl orthosilicate dispersion;

[0046] Weighing: 1000.0 mL of nano-titanium dioxide dispersion liquid is added to the reaction kettle for stirring, and after the pH of the reaction system is adjusted to 9 using saturated sodium hydroxide, 50.0 mL of tetraethyl orthosilicate dispersion liquid is added dropwise into the reaction kettle, which is completed within 10 min and stirred at room temperature for 4 h. After the reaction is completed, the temperature of the reaction kettle is reduced to room temperature, the filter cake is collected by filtration, and the filter cake is washed with anhydrous ethanol and deionized water for 3 times. Then, the filter cake is transferred to a drying box with a temperature of 80℃, and vacuum dried to room temperature to obtain the composite microparticles.

[0047] Step 2, preparation of modified microparticles

[0048] Weighing: 10.0 g of the composite microparticles, 200.0 mL of anhydrous ethanol and 100.0 mL of deionized water are added to the reaction kettle for stirring. After the temperature of the reaction kettle is increased to 40℃, the pH of the reaction system is adjusted to 9 using saturated sodium hydroxide. Then, 3.0 g of 3-aminopropyltrimethoxysilane is added to the reaction kettle, and the reaction is stirred for 2 h. After the reaction is completed, the temperature of the reaction kettle is reduced to room temperature, the filter cake is collected by filtration, and the filter cake is washed with anhydrous ethanol and deionized water for 3 times. Then, the filter cake is transferred to a drying box with a temperature of 80℃, and vacuum dried to room temperature to obtain the modified microparticles.

[0049] Step 3, preparation of modified liquid

[0050] Weighing: 10.0 g of the modified microparticles and 100.0 mL of N,N-dimethylformamide are added to the reaction kettle for stirring. After the protection of nitrogen is introduced, the reaction system is added with 1,6-hexane diisocyanate which is 0.60 times the molar amount of the amino group in the reaction system. The reaction is stirred at room temperature for 30 min to obtain the modified liquid.

[0051] Step 4, preparation of modified flexibilizer

[0052] Under the protection of nitrogen, 100.0 mL of the modified liquid and 0.3 g of dibutyltin dilaurate are added to the reaction kettle for stirring. After the temperature of the reaction kettle is increased to 50℃, the reaction system is added with polyethylene glycol which is 0.55 times the isocyanate group in the reaction system, and N-[(4-methyl-1H-benzotriazole-1-yl)methyl] diethanolamine which is 0.10 times the isocyanate group in the reaction system. After the reaction is heated for 2 h, the reaction is completed, and the temperature of the reaction kettle is reduced to room temperature. Then, the reaction liquid is transferred to a rotary evaporator with a temperature of 100℃, and distilled under reduced pressure until no liquid is collected to obtain the modified flexibilizer.

[0053] Example 2

[0054] The present embodiment provides a preparation method of a modified flexibilizer for preparing a high-flexibility weather-resistant cable material for new energy electric vehicles, which comprises the following steps:

[0055] Step 1, preparation of composite microparticles

[0056] Weigh 20.0 g of nano-titanium dioxide, 800.0 mL of anhydrous ethanol, and 200.0 mL of deionized water to obtain a nano-titanium dioxide dispersion.

[0057] Weigh 8.0 mL of methyl orthosilicate and 60.0 mL of anhydrous ethanol and mix to obtain a ethyl orthosilicate dispersion;

[0058] Weigh: 1000.0mL of nano-titanium dioxide dispersion was added to the reactor and stirred. After adjusting the pH of the reaction system to 10 with saturated sodium hydroxide, 60.0mL of ethyl orthosilicate dispersion was added dropwise to the reactor. The addition was completed within 15 minutes and stirred at room temperature for 5 hours. After the reaction was completed, the temperature of the reactor was lowered to room temperature, the reaction mixture was filtered to collect the filter cake, and the filter cake was washed 5 times with anhydrous ethanol and deionized water. The filter cake was transferred to a drying oven at 80°C and vacuum dried to room temperature to obtain composite particles.

[0059] Step ②: Preparation of modified microparticles

[0060] Weigh: 10.0g of composite particles, 300.0mL of anhydrous ethanol and 100.0mL of deionized water were added to the reactor and stirred. After the temperature of the reactor was raised to 60°C, the pH of the reaction system was adjusted to 10 using saturated sodium hydroxide, and 3.0g of 3-aminopropyltrimethoxysilane was added to the reactor. The mixture was kept warm and stirred for 4h. After the reaction was completed, the temperature of the reactor was lowered to room temperature, the reaction mixture was filtered to collect the filter cake, and the filter cake was washed 5 times with anhydrous ethanol and deionized water. The filter cake was transferred to a drying oven at 80°C and vacuum dried to room temperature to obtain modified particles.

[0061] Step 3: Prepare modified liquid

[0062] 10.0 g of modified microparticles and 120.0 mL of N,N-dimethylformamide were weighed and added to a reactor with stirring. After nitrogen protection, 1,6-hexamethylene diisocyanate (0.65 times the molar amount of amino groups in the reaction system) was added to the reactor and stirred at room temperature for 40 min to obtain a modified solution.

[0063] Step ④: Preparation of modified flexibilizer

[0064] Under the protection of nitrogen, 120.0 mL of the modified liquid and 0.3 g of dibutyltin dilaurate were added to the reactor and stirred. After the temperature of the reactor was raised to 60° C., polyethylene glycol with 0.65 times the isocyanate group in the reaction system and N-[(4-methyl-1H-benzotriazole-1-yl)methyl]diethanolamine with 0.15 times the isocyanate group in the reaction system were added to the reactor. After the reaction was kept warm for 4 hours, after the reaction was completed, the temperature of the reactor was lowered to room temperature, the reaction liquid was transferred to a rotary evaporator with a temperature of 100° C., and distilled under reduced pressure until no liquid was extracted to obtain a modified flexible agent.

[0065] Example 3

[0066] This embodiment provides a method for preparing a modified flexibilizer for preparing a highly flexible and weather-resistant cable material for new energy electric vehicles, comprising the following steps:

[0067] Step ①: Preparation of composite microparticles

[0068] Weigh 16.0 g of nano-titanium dioxide, 800.0 mL of anhydrous ethanol, and 200.0 mL of deionized water to obtain a nano-titanium dioxide dispersion.

[0069] Weigh 7.0 mL of methyl orthosilicate and 54.0 mL of anhydrous ethanol to obtain a ethyl orthosilicate dispersion.

[0070] Weigh: 1000.0mL of nano-titanium dioxide dispersion was added to the reactor and stirred. After adjusting the pH of the reaction system to 10 with saturated sodium hydroxide, 54.0mL of ethyl orthosilicate dispersion was added dropwise to the reactor. The addition was completed within 12 minutes and stirred at room temperature for 5 hours. After the reaction was completed, the temperature of the reactor was lowered to room temperature, the reaction mixture was filtered to collect the filter cake, and the filter cake was washed 4 times with anhydrous ethanol and deionized water. The filter cake was transferred to a drying oven at 80°C and vacuum dried to room temperature to obtain composite particles.

[0071] Step ②: Preparation of modified microparticles

[0072] Weigh: 10.0g of composite particles, 300.0mL of anhydrous ethanol and 100.0mL of deionized water were added to the reactor and stirred. After the temperature of the reactor was raised to 50°C, the pH of the reaction system was adjusted to 10 using saturated sodium hydroxide, and 3.0g of 3-aminopropyltrimethoxysilane was added to the reactor. The mixture was kept warm and stirred for 3h. After the reaction was completed, the temperature of the reactor was lowered to room temperature, the reaction mixture was filtered to collect the filter cake, and the filter cake was washed 4 times with anhydrous ethanol and deionized water. The filter cake was transferred to a drying oven at 80°C and vacuum dried to room temperature to obtain modified particles.

[0073] Step 3: Prepare modified liquid

[0074] 10.0 g of modified microparticles and 120.0 mL of N,N-dimethylformamide were weighed and added to a reactor with stirring. After nitrogen protection, 1,6-hexamethylene diisocyanate (0.64 times the molar amount of amino groups in the reaction system) was added to the reactor and stirred at room temperature for 35 min to obtain a modified solution.

[0075] Step ④: Preparation of modified flexibilizer

[0076] Under the protection of nitrogen, 120.0 mL of the modified liquid and 0.3 g of dibutyltin dilaurate were added to the reactor and stirred. After the temperature of the reactor was raised to 55° C., polyethylene glycol with 0.64 times the isocyanate group in the reaction system and N-[(4-methyl-1H-benzotriazole-1-yl)methyl]diethanolamine with 0.12 times the isocyanate group in the reaction system were added to the reactor. After the reaction was kept warm for 3 hours, after the reaction was completed, the temperature of the reactor was lowered to room temperature, the reaction liquid was transferred to a rotary evaporator with a temperature of 100° C., and distilled under reduced pressure until no liquid was extracted to obtain a modified flexible agent.

[0077] Example 4

[0078] This embodiment provides a method for preparing a composite polyurethane for preparing a highly flexible weather-resistant cable material for new energy electric vehicles, comprising the following steps:

[0079] Step I: Preparation of modified polyurethane

[0080] Weigh: 80.0g of hydroxy silicone oil, 300.0mL of N,N-dimethylformamide and 3.0g of dibutyltin dilaurate were added to the reactor. After nitrogen protection, 1,6-hexamethylene diisocyanate with a molar amount of 0.55 times that of the hydroxyl group in the reaction system was added to the reactor. The temperature of the reactor was raised to 50°C. After the reaction was kept warm for 1h, 10.0g of the modified flexibilizer prepared in Example 1 was continued to be added to the reactor. After the reaction was completed, the temperature of the reactor was lowered to room temperature, the reaction solution was transferred to a rotary evaporator at a temperature of 100°C, and distilled under reduced pressure until no liquid was extracted to obtain a modified polyurethane.

[0081] Step II: Preparation of composite polyurethane

[0082] Weigh: 80.0g modified polyurethane, 10.0g triethylamine and 800.0mL N,N-dimethylformamide are added to the reactor, and after nitrogen protection, the temperature of the reactor is dropped to 0-5°C and 0.25 times the molar amount of hydroxyl group in the reaction system is added dropwise to the reactor. After the addition is completed within 10 minutes, the temperature of the reactor is gradually returned to room temperature and kept warm for 2 hours. After the reaction is completed, the temperature of the reactor is lowered to room temperature, and the reaction liquid is transferred to a rotary evaporator at a temperature of 100°C and distilled under reduced pressure until no liquid is extracted to obtain a composite polyurethane.

[0083] Example 5

[0084] This embodiment provides a method for preparing a composite polyurethane for preparing a highly flexible weather-resistant cable material for new energy electric vehicles, comprising the following steps:

[0085] Step I: Preparation of modified polyurethane

[0086] Weigh: 100.0g of hydroxy silicone oil, 360.0mL of N,N-dimethylformamide and 5.0g of dibutyltin dilaurate were added to the reactor. After nitrogen protection, 1,6-hexamethylene diisocyanate with a molar amount of 0.60 times the hydroxyl group in the reaction system was added to the reactor. The temperature of the reactor was raised to 60°C. After the reaction was kept warm for 1h, 10.0g of the modified flexibilizer prepared in Example 2 was continued to be added to the reactor. After the reaction was completed, the temperature of the reactor was lowered to room temperature, the reaction solution was transferred to a rotary evaporator at a temperature of 100°C, and distilled under reduced pressure until no liquid was extracted to obtain a modified polyurethane.

[0087] Step II: Preparation of composite polyurethane

[0088] Weigh: 100.0 g of modified polyurethane, 20.0 g of triethylamine and 1000.0 mL of N,N-dimethylformamide are added to a reactor. After nitrogen protection, the temperature of the reactor is dropped to 0°C and 0.30 times the molar amount of hydroxyl group in the reaction system is added dropwise to the reactor. After the addition is completed within 15 minutes, the temperature of the reactor is gradually returned to room temperature and kept warm for 2 hours. After the reaction is completed, the temperature of the reactor is lowered to room temperature, the reaction liquid is transferred to a rotary evaporator at a temperature of 100°C, and distilled under reduced pressure until no liquid is extracted to obtain a composite polyurethane.

[0089] Example 6

[0090] This embodiment provides a method for preparing a composite polyurethane for preparing a highly flexible weather-resistant cable material for new energy electric vehicles, comprising the following steps:

[0091] Step I: Preparation of modified polyurethane

[0092] Weigh: 90.0g of hydroxy silicone oil, 320.0mL of N,N-dimethylformamide and 4.0g of dibutyltin dilaurate were added to the reactor. After nitrogen protection, 1,6-hexamethylene diisocyanate with a molar amount of 0.58 times the hydroxyl group in the reaction system was added to the reactor. The temperature of the reactor was raised to 55°C. After the reaction was kept warm for 2h, 10.0g of the modified flexibilizer prepared in Example 3 was continued to be added to the reactor. After the reaction was completed, the temperature of the reactor was lowered to room temperature, the reaction solution was transferred to a rotary evaporator at a temperature of 100°C, and distilled under reduced pressure until no liquid was extracted to obtain a modified polyurethane.

[0093] Step II: Preparation of composite polyurethane

[0094] Weigh: 90.0g modified polyurethane, 16.0g triethylamine and 9600.0mL N,N-dimethylformamide are added to the reactor. After nitrogen protection, the temperature of the reactor is dropped to 3°C and 0.28 times the molar amount of hydroxyl group in the reaction system is added dropwise to the reactor. After the addition is completed within 12 minutes, the temperature of the reactor gradually returns to room temperature and the reaction is kept warm for 2 hours. After the reaction is completed, the temperature of the reactor is lowered to room temperature, the reaction liquid is transferred to a rotary evaporator at a temperature of 100°C, and distilled under reduced pressure until no liquid is produced to obtain a composite polyurethane.

[0095] Example 7

[0096] This embodiment provides a method for preparing a highly flexible weather-resistant cable material for new energy electric vehicles, comprising the following steps:

[0097] Step 1: Prepare the cable core

[0098] Polyvinyl chloride was added into a twin-screw extruder. The temperatures of the eight temperature zones of the twin-screw extruder from the feed port to the discharge port were 150°C, 155°C, 160°C, 160°C, 165°C, 165°C, 170°C, and 170°C, respectively. The main engine speed of the twin-screw extruder was 80 rpm and the pressure was 100 bar. The polyvinyl chloride was melt-extruded and coated on the surface of a copper wire with a diameter of 0.4 mm. After curing, a cable core 1 with a thickness of 1.0 mm was obtained.

[0099] Step 2: Prepare the wrapping layer

[0100] Copper tape was wrapped around the surfaces of the seven cable cores to obtain a wrapping layer 2 with a thickness of 0.3 mm.

[0101] Step 3: Prepare the outer sheath layer

[0102] Step 3: Prepare weather-resistant cable materials

[0103] In parts by weight, 80 parts of the composite polyurethane prepared in Example 4, 1 part of N,N'-diphenyl-p-phenylenediamine, 1 part of polyethylene wax and 5 parts of dibutyl phthalate were weighed and added to a twin-screw extruder. The temperatures of the eight temperature sections of the twin-screw extruder from the feed port toward the discharge port were 170°C, 175°C, 190°C, 190°C, 195°C, 195°C, 200°C and 200°C, respectively. The main engine speed of the twin-screw extruder was 80 rpm and the pressure was 100 bar. The melt extrusion was coated on the surface of the cable core, and after curing, a sheath layer 3 with a thickness of 1.5 mm was obtained to obtain a weather-resistant cable material.

[0104] Example 8

[0105] This embodiment provides a method for preparing a highly flexible weather-resistant cable material for new energy electric vehicles, comprising the following steps:

[0106] Step one, preparing cable core

[0107] The polyvinyl chloride was added into the twin-screw extruder, the temperature of eight temperature sections of the twin-screw extruder from the feeding port to the discharging port was 150℃, 155℃, 160℃, 160℃, 165℃, 165℃, 170℃, 170℃ respectively, the main machine rotating speed of the twin-screw extruder was 120 rpm, the pressure was 150 bar, and the polyvinyl chloride was melt-extruded to coat on the surface of the copper wire with a diameter of 0.4 mm, and the cable core 1 with a thickness of 1.0 mm was obtained after solidification.

[0108] Step two, preparing the wrapping layer

[0109] The copper tape was used to wrap on the surface of the seven cable cores to obtain the wrapping layer 2 with a thickness of 0.3 mm.

[0110] Step three, preparing the outer sheath layer

[0111] Step three, preparing the weather-resistant cable material

[0112] According to parts by weight, 100 parts of the composite polyurethane prepared in Example 5, 2 parts of N,N'-diphenyl-p-phenylenediamine, 2 parts of polyethylene wax and 6 parts of dibutyl phthalate were added into the twin-screw extruder, the temperature of eight temperature sections of the twin-screw extruder from the feeding port to the discharging port was 170℃, 175℃, 190℃, 190℃, 195℃, 195℃, 200℃, 200℃ respectively, the main machine rotating speed of the twin-screw extruder was 100 rpm, the pressure was 120 bar, and the polyvinyl chloride was melt-extruded to coat on the surface of the cable core, and the sheath layer 3 with a thickness of 1.5 mm was obtained after solidification, thereby obtaining the weather-resistant cable material.

[0113] Example 9

[0114] The present embodiment provides a preparation method of a high-flexibility weather-resistant cable material for new energy electric vehicles, comprising the following steps:

[0115] Step one, preparing cable core

[0116] The polyvinyl chloride was added into the twin-screw extruder, the temperature of eight temperature sections of the twin-screw extruder from the feeding port to the discharging port was 150℃, 155℃, 160℃, 160℃, 165℃, 165℃, 170℃, 170℃ respectively, the main machine rotating speed of the twin-screw extruder was 100 rpm, the pressure was 120 bar, and the polyvinyl chloride was melt-extruded to coat on the surface of the copper wire with a diameter of 0.4 mm, and the cable core 1 with a thickness of 1.0 mm was obtained after solidification.

[0117] Step two, preparing the wrapping layer

[0118] Copper tape was wrapped around the surfaces of the seven cable cores to obtain a wrapping layer 2 with a thickness of 0.3 mm.

[0119] Step 3: Prepare weather-resistant cable materials

[0120] In parts by weight, 96 parts of the composite polyurethane prepared in Example 6, 2 parts of N,N'-diphenyl-p-phenylenediamine, 2 parts of polyethylene wax and 6 parts of dibutyl phthalate were weighed and added to a twin-screw extruder. The temperatures of the eight temperature zones of the twin-screw extruder from the feed port toward the discharge port were 170°C, 175°C, 190°C, 190°C, 195°C, 195°C, 200°C and 200°C, respectively. The main engine speed of the twin-screw extruder was 100 rpm and the pressure was 120 bar. The melt extrusion was coated on the surface of the cable core, and after curing, a sheath layer 3 with a thickness of 1.5 mm was obtained to obtain a weather-resistant cable material.

[0121] Comparative Example 1

[0122] The difference between this comparative example and Example 9 is that, during the preparation of the composite polyurethane used in step 3, the modified flexibilizer used in the preparation process is eliminated from step ①, and in step ②, an equal amount of nano-titanium dioxide is used to replace the composite fine particles.

[0123] Comparative Example 2

[0124] The difference between this comparative example and Example 9 is that the modified flexibilizer is not used during the preparation of the composite polyurethane used in step 3.

[0125] Comparative Example 3

[0126] The difference between this comparative example and Example 9 is that, during the preparation of the composite polyurethane used in step 3, the modified flexibilizer used in step 3 is eliminated from step ②, and in step ③, an equal amount of composite microparticles are used instead of modified microparticles.

[0127] Performance testing:

[0128] The vertical burning ratings of the weather-resistant cable materials prepared in Examples 7-9 and Comparative Examples 1-3 were determined with reference to the standard GB / T 32129-2015 “Halogen-free and low-smoke flame-retardant cable materials for wires and cables”;

[0129] The flexibility of the weather-resistant cable materials prepared in Examples 7-9 and Comparative Examples 1-3 was tested according to the standard JB / T 10696.3-2007 "Test methods for mechanical and physical and chemical properties of wires and cables - Part 3: Bending test". The flexibility of the weather-resistant cable material was defined by the number of winding turns of the weather-resistant cable material.

[0130] The abrasion resistance of the weather-resistant cable material prepared in Examples 7-9 and Comparative Examples 1-3 was tested according to the standard GB / T 17737.324-2018 "Coaxial cables Part 1-324: Mechanical test methods Cable abrasion resistance test" Example 7-9 and Comparative Example 1-3, and the number of cycles of the blade to wear through the sheath layer of the weather-resistant cable material sample was defined as the abrasion resistance of the cable sheath layer sample;

[0131] The weather-resistant cable material prepared in Examples 7-9 and Comparative Examples 1-3 was subjected to ultraviolet aging test according to the standard GB / T 16422.3-2022 "Plastics - Laboratory light source exposure test methods - Part 3: Fluorescent UV lamps", and the number of windings and cycles of the outer sheath layer of the weather-resistant cable material after ultraviolet aging was calculated according to the standards JB / T10696.3-2007 and GB / T 17737.324-2018, and the specific data is shown in Table 1;

[0132] Table 1 - Performance test data table of each sample

[0133]

[0134] Data analysis:

[0135] After comparing and analyzing the data in Table 1, it can be found that the weather-resistant cable material prepared by the present application has a vertical burning level of V-0, a winding number of 13, a cycle number of 106, and after ultraviolet aging, the winding number is 12 and the cycle number is 104, all of which are better than the comparative examples, which shows that:

[0136] In Comparative Example 1, TiO2 in the system is not coated with a SiO2 shell, losing the coating stability of the core-shell structure to the particles, and the bare TiO2 particles are prone to agglomeration in the polymer matrix, resulting in poor particle dispersion and weak interface compatibility. This poor dispersion will form a micro stress concentration area during thermal or mechanical stress loading, inducing crack initiation and propagation, resulting in a significant decrease in winding number and cycle number; at the same time, TiO2 has strong photocatalytic activity, and when not coated, it can accelerate the degradation of the polymer under ultraviolet irradiation, further degrading the mechanical properties of the material after ultraviolet aging, resulting in a significant decrease in cycle number and winding performance. In addition, the SiO2 shell also plays an important role in thermal isolation during combustion, and the absence of the SiO2 shell results in poor thermal stability and carbonization ability, leading to a decrease in flame retardant performance;

[0137] The comparative example 2 does not add a modified flexibilizer in the formula, and the material completely relies on the main chain structure to provide performance support. Under this design, the polymer chain is relatively rigid and lacks flexibility, and cannot fully release stress under repeated bending or stretching conditions, resulting in a significant decrease in the number of winding turns and cycle life; at the same time, during the ultraviolet aging process, the material molecular structure lacks sufficient fracture absorption capacity, resulting in the formation of cracks or chain segment fracture under local ultraviolet irradiation, causing rapid performance degradation, and the performance after aging is almost halved; in addition, the absence of inorganic particles also means the lack of rigid filler support and interface energy consumption mechanism, resulting in a double damage to the thermal stability and mechanical fatigue resistance;

[0138] In the comparative example 3, although inorganic particles are added, due to the lack of silane coupling agent graft modification, the particle surface is still a hydrophilic inorganic interface, which is difficult to achieve good interface compatibility with the organic polymer matrix. This interface mismatch easily forms a weak interface zone during compounding, and the particles are not uniformly distributed in the material, and even micro-pores and debonding problems occur, thereby weakening the overall mechanical bearing capacity of the material, resulting in a decrease in the number of winding turns and cycle life, especially during long-term use or ultraviolet aging process, interface debonding and crack propagation are intensified, accelerating performance degradation; in addition, the unmodified particles on the surface are prone to agglomeration, reducing dispersion stability, and limiting the role of the particles in improving flame retardation, mechanics and aging resistance, etc.

[0139] Finally, it is explained that the present scheme successfully prepares a cable sheath material with excellent weather resistance through the synergistic construction of organic-inorganic heterogeneous components. The TiO2@SiO2core-shell structure constructed under alkaline catalysis conditions realizes high dispersibility and interface stability of the microparticles; the covalent bond formed by introducing the silane coupling agent effectively improves the compatibility of the organic-inorganic interface, providing reaction sites for subsequent functionalization reactions; the modified microparticles and the polyurethane matrix form a multiple network crosslinking through the urethane bond and the phosphate structure, further enhancing the mechanical properties and thermal stability of the material; at the same time, the flexibilizer containing a triazole ring improves flexibility and anti-aging performance, and also endows the system with good antioxidant capacity; through chemical bond connection and physical synergistic effect between components, the organic unity of structural stability, flexibility and environmental adaptability is realized.

[0140] The preferred embodiments disclosed above are only used to help explain the present application. The preferred embodiments do not describe all the details and limit the present application to the specific embodiments. Obviously, many modifications and changes can be made according to the content of the present application. The embodiments are selected and described in detail in order to better explain the principles and practical applications of the present application, so that those skilled in the art can well understand and utilize the present application. The present application is limited by the claims and their entire scope and equivalents.

Claims

1. A highly flexible weather-resistant cable material for new energy electric vehicles, characterized in that: It comprises a plurality of cable cores (1), a wrapping layer (2) and a sheath layer (3) arranged in sequence from the inside out; The cable core (1) is obtained by melt-extruding polyvinyl chloride and coating it on the surface of a copper conductor; the wrapping layer (2) is obtained by wrapping a copper tape around the surface of the cable core (1); the outer sheath layer (3) is obtained by melt-extruding a composite polyurethane material, coating it on the surface of the cable core (2), and then solidifying it; The composite polyurethane material comprises the following raw materials in parts by weight: 80-100 parts of composite polyurethane, 1-2 parts of antioxidant, 1-2 parts of lubricant and 5-8 parts of plasticizer; The preparation method of the composite polyurethane comprises the following steps: adding modified polyurethane, triethylamine and N,N-dimethylformamide into a reactor, introducing nitrogen for protection, lowering the temperature of the reactor to 0-5°C, and dropwise adding a calculated amount of phosphorus oxychloride into the reactor, after the dropwise addition is completed within 10-15 minutes, gradually raising the temperature of the reactor to room temperature, maintaining the temperature for reaction for 2 hours, and performing post-processing to obtain the composite polyurethane.

2. A highly flexible weather-resistant cable material for new energy electric vehicles according to claim 1, characterized in that: In the process of preparing composite polyurethane, the usage ratio of modified polyurethane, triethylamine and N,N-dimethylformamide is 8-10g:1-2g:80-100mL, and the usage amount of phosphorus oxychloride is 0.25-0.30 times the molar amount of hydroxyl groups in the reaction system.

3. The highly flexible weather-resistant cable material for new energy electric vehicles according to claim 1, characterized in that: The preparation method of the modified polyurethane comprises the following steps: adding hydroxy silicone oil, N,N-dimethylformamide and dibutyltin dilaurate into a reactor, introducing nitrogen protection, adding a calculated amount of 1,6-hexamethylene diisocyanate into the reactor, raising the temperature of the reactor to 50-60° C., keeping the temperature for reaction for 1-2 hours, continuing to add a modified flexibilizer into the reactor, and performing post-processing to obtain the modified polyurethane.

4. A highly flexible weather-resistant cable material for new energy electric vehicles according to claim 3, characterized in that: The dosage ratio of the hydroxy silicone oil, N,N-dimethylformamide, dibutyltin dilaurate and modified flexibilizer is 8-10g:30-36mL:0.3-0.5g:1g, wherein the dosage of isophorone diisocyanate is 0.55-0.60 times the molar amount of hydroxyl groups in the reaction system.

5. The highly flexible weather-resistant cable material for new energy electric vehicles according to claim 3, characterized in that: The preparation method of the modified flexibilizer comprises the following steps: A1. Add the modified microparticles and N,N-dimethylformamide to a reactor and stir. After nitrogen protection, add the calculated amount of 1,6-hexamethylene diisocyanate to the reactor and stir at room temperature for 30-40 minutes to obtain a modified solution. A2. Under nitrogen protection, the modified liquid and dibutyltin dilaurate were added to the reactor and stirred. After the temperature of the reactor was raised to 50-60°C, the calculated amount of polyethylene glycol and N-[(4-methyl-1H-benzotriazole-1-yl)methyl]diethanolamine were added to the reactor. After the reaction was kept warm for 2-4 hours, the modified flexibilizer was obtained by post-treatment.

6. A highly flexible weather-resistant cable material for new energy electric vehicles according to claim 5, characterized in that: In step A1, the amount ratio of modified particles and N,N-dimethylformamide is 1g:10-12mL, wherein the amount of 1,6-hexamethylene diisocyanate is 0.60-0.65 times the molar amount of amino groups in the reaction system; in step A2, the amount ratio of modified liquid and dibutyltin dilaurate is 10-12mL:0.03g, wherein the amount of polyethylene glycol is 0.55-0.65 times the amount of isocyanate groups in the reaction system, and the amount of N-[(4-methyl-1H-benzotriazol-1-yl)methyl]diethanolamine is 0.10-0.15 times the amount of isocyanate groups in the reaction system.

7. The highly flexible weather-resistant cable material for new energy electric vehicles according to claim 5, characterized in that: The preparation method of the modified microparticles comprises the following steps: B1. Add the nano-titanium dioxide dispersion into a reactor and stir. Use saturated sodium hydroxide to adjust the pH of the reaction system to 9-10. Then, add the ethyl orthosilicate dispersion dropwise into the reactor within 10-15 minutes and stir at room temperature for 4-5 hours. Post-treat to obtain composite particles. B2. Add the composite microparticles, anhydrous ethanol and deionized water into a reactor and stir. After the temperature of the reactor is raised to 40-60°C, use saturated sodium hydroxide to adjust the pH of the reaction system to 9-10, add 3-aminopropyltrimethoxysilane into the reactor, keep warm and stir for 2-4 hours, and post-treat to obtain modified microparticles.

8. The highly flexible weather-resistant cable material for new energy electric vehicles according to claim 7, characterized in that: In step B1, the nano-titanium dioxide dispersion and the ethyl orthosilicate dispersion are used in a ratio of 80-100 mL:5-6 mL, wherein the nano-titanium dioxide dispersion is obtained by mixing nano-titanium dioxide, anhydrous ethanol and deionized water in a ratio of 1-2 g:80 mL:20 mL, and the ethyl orthosilicate dispersion is obtained by mixing methyl orthosilicate and anhydrous ethanol in a ratio of 0.6-0.8 mL:5-6 mL; in step B2, the composite particles, anhydrous ethanol, deionized water and 3-aminopropyltrimethoxysilane are used in a ratio of 1 g:20-30 mL:10 mL:0.3 g.

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