Flame-retardant high-dielectric lightweight nylon material and preparation method thereof

Abstract

The invention relates to the technical field of nylon materials, in particular to a flame-retardant high-dielectric lightweight nylon material and a preparation method thereof.The flame-retardant high-dielectric lightweight nylon material is prepared from, by mass, 70%-80% of copolymerized nylon, 3%-6% of melamine cyanurate, 6%-8% of barium titanate, 5%-10% of hollow glass beads, 1%-2% of silane coupling agents, 0.5%-1% of polyvinylpyrrolidone, 0.3%-0.5% of antioxidants and 0.2%-1% of lubricating agents. According to the invention, a stable flame-retardant network is constructed through chemical grafting, and an interface synergistic modification technology is adopted, so that flame-retardant, high-dielectric and lightweight synergistic enhancement is realized, mechanical properties and processing stability are considered, and long-acting reliability and aging resistance of the material under complex working conditions are ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of nylon materials, and particularly to a flame-retardant high-dielectric lightweight nylon material and a preparation method thereof. Background Art

[0002] Nylon (PA), as a thermoplastic engineering plastic with excellent comprehensive properties, has been widely used in the fields of automotive industry, electronic appliances, synthetic fibers, and construction due to its excellent heat resistance, wear resistance, chemical corrosion resistance, and self-lubricating properties. However, traditional nylon materials have significant limitations. Unmodified nylon is prone to producing molten droplets during combustion, posing a risk of secondary fires. In addition, its low dielectric constant makes it difficult to meet the high-dielectric performance requirements of high-end electronic products for capacitors, energy storage devices, and high-frequency circuits. At the same time, there is still room for improvement in fields with strict lightweight requirements such as aerospace and new energy vehicles. With the rapid development of the electronic and electrical industries and the iterative upgrading of new energy vehicle and aerospace technologies, the market demand for composite materials with flame retardancy, high dielectricity, and lightweight characteristics has increased sharply. For example, in the field of new energy vehicles, it can be used for battery pack shells and motor components to improve safety and endurance; in the field of electronic appliances, it can optimize the stability of components such as capacitors and circuit boards; in the aerospace field, weight reduction and efficiency improvement can be achieved through lightweight structural components.

[0003] In the prior art, the interfacial bonding force between the flame retardant, dielectric filler, and nylon matrix is weak, prone to phase separation or interfacial defects, and the interfacial compatibility of multi-components is poor, resulting in performance attenuation of the material during long-term use, fluctuations in dielectric performance, reduction in flame retardancy efficiency, affecting processing fluidity, and increasing the risk of internal defects in products. In addition, traditional flame retardants such as halogen-based or phosphorus-based ones can improve flame retardancy, but may reduce the dielectric performance of the material, resulting in increased dielectric loss or unstable dielectric constant, while the introduction of high-dielectric fillers may weaken the flame retardant effect. Summary of the Invention

[0004] In order to solve the problems mentioned in the above background art, the present invention provides a flame-retardant high-dielectric lightweight nylon material and a preparation method thereof.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: A flame-retardant high-dielectric lightweight nylon material, comprising the following raw materials by mass percentage: 70 - 80% of copolyamide nylon, 3 - 6% of melamine cyanurate, 6 - 8% of barium titanate, 5 - 10% of hollow glass microspheres, 1 - 2% of silane coupling agent, 0.5 - 1% of polyvinylpyrrolidone, 0.3 - 0.5% of antioxidant, and 0.2 - 1% of lubricant.

[0006] Further, the copolyamide nylon is prepared through the following steps: S1. Add caprolactam and sodium hydroxide into a reactor. Under nitrogen protection, heat up and stir for 2 - 3 h, then add 10 wt% acetic anhydride to terminate the reaction, continue stirring for 30 - 40 min, cool down the system, dropwise add methacryloyl chloride solution pre - dissolved in dimethyl sulfoxide, and simultaneously add triethylamine. React for 4 - 6 h, pour the product into ice water for precipitation, wash it with ethanol 3 times after filtration, and dry it at 60 °C for 12 h to obtain V - PA6; S2. Add V - PA6 and allyl diethyl phosphonate into a reactor pre - filled with N,N - dimethylformamide, add part of diisopropylbenzene peroxide. Under nitrogen protection, heat up and stir for the first time for 2 - 3 h, then heat up for the second time, add the remaining diisopropylbenzene peroxide, and continue stirring for 2 - 3 h. After the reaction ends, recover N,N - dimethylformamide by vacuum distillation, cool it to room temperature, pour the remaining material into ice methanol for precipitation, wash it with methanol 3 times after filtration, and dry it at 60 °C for 24 h to obtain the copolymer nylon.

[0007] Further, the silane coupling agent includes one or more of KH - 550, KH - 560, KH - 570, A - 172, and Si - 69.

[0008] Further, the antioxidant includes one or more of antioxidant 1010, antioxidant 1098, antioxidant 245, antioxidant 168, and antioxidant 2246.

[0009] Further, the lubricant includes one or more of ethylene bisstearamide, stearic acid amide, polydimethylsiloxane, pentaerythritol stearate, and polyethylene wax.

[0010] Further, in step S1, the mass ratio of caprolactam, sodium hydroxide, dimethyl sulfoxide, methacryloyl chloride solution, and triethylamine is (58 - 60):(0.5 - 0.6):(20 - 25):(5.2 - 5.6):(4.0 - 4.3).

[0011] Further, in step S1, the heating temperature is 250 - 260 °C, the stirring speed is 200 - 300 rpm, and the cooling temperature is 80 - 85 °C.

[0012] Further, in step S2, the mass ratio of V - PA6, allyl diethyl phosphonate, N,N - dimethylformamide, and diisopropylbenzene peroxide is (64 - 66):(36 - 38):(100 - 150):(2 - 3), where the first addition amount of diisopropylbenzene peroxide is 60 - 70% of the total mass of diisopropylbenzene peroxide, and the remaining 30 - 40% is added during the second heating stage.

[0013] Furthermore, in step S2, the temperature of the first temperature rise is 85 - 90 °C, the temperature of the second temperature rise is 100 - 110 °C, and the stirring speed is 100 - 200 rpm.

[0014] According to another aspect of the present invention, there is provided a method for preparing the above-mentioned flame-retardant high-dielectric lightweight nylon material, comprising the following steps: Add copolyamide, melamine cyanurate, barium titanate, hollow glass microspheres, silane coupling agent, polyvinylpyrrolidone, antioxidant and lubricant into a mixer according to mass percentages, mix at a speed of 2000 - 3000 rpm for 10 - 20 min, load into a twin-screw extruder, the granulation temperature is 240 - 245 °C, the screw speed is 100 - 200 rpm, the extruded strip is water-cooled and pelletized, and pellets with a diameter of 3 mm are obtained after pelletization, and then injection molded to obtain the flame-retardant high-dielectric lightweight nylon material.

[0015] The beneficial effects of the present invention: 1. In the technical solution of the present invention, in the preparation of copolyamide, first, an active group containing a double bond is introduced into the nylon main chain through chemical grafting, and then a phosphonate functional monomer is grafted onto the nylon chain by free radical copolymerization to form a stable chemical bonding flame-retardant network. The phosphonate group can not only inhibit flame propagation by capturing gas-phase free radicals during combustion, but also promote the carbonization of the nylon matrix to form a dense protective layer, while avoiding the negative impact of traditional flame retardants on dielectric properties. Combined with the surface modification of the high-dielectric barium titanate filler with a silane coupling agent, a uniformly dispersed polarization micro-region is constructed in the matrix, so that while the flame-retardant efficiency of the material is significantly improved, the dielectric constant and dielectric stability are enhanced synchronously.

[0016] 2. In the technical solution of the present invention, hollow glass microspheres are introduced as a lightweight reinforcing phase, and high interfacial bonding force between the microspheres and the nylon matrix is achieved through surface coupling agent treatment, solving the problem of deterioration of mechanical properties caused by uneven dispersion of fillers in lightweight materials. The closed-cell structure of the microspheres effectively reduces the material density, and the chemical bonding and physical anchoring effects between its surface and the matrix can uniformly transfer stress, avoiding the propagation of microcracks caused by stress concentration. In addition, the branched structure of the copolyamide main chain improves toughness while maintaining the rigidity of the material through the flexible buffering effect of intermolecular chain cross-linking points, avoiding the brittle defects caused by excessive filling in traditional lightweight materials.

[0017] 3. In the technical solution of the present invention, the surface modification of barium titanate and hollow microspheres by silane coupling agent, and the coating effect of polyvinylpyrrolidone on melamine cyanurate significantly improve the multi-phase interface bonding state and inhibit the filler agglomeration and phase separation phenomenon. During the processing, the synergistic effect of the lubricant and the modified filler reduces the melt viscosity, ensures the melt blending uniformity at a high filler content, avoids internal defects (such as pores and cracks) in the product caused by insufficient fluidity, and at the same time maintains the thermal stability and long-term use reliability of the material.

[0018] 4. In the technical solution of the present invention, the chemically grafted phosphonate flame retardant network stably exists in the nylon matrix through covalent bonds, avoiding the migration and precipitation of small molecule flame retardants. The surface-modified dielectric filler resists the performance degradation caused by damp heat aging through strong interface bonding. The synergistic effect of the antioxidant and the stabilizing agent further inhibits the oxidative degradation of the material during high-temperature processing and use, enabling the material to maintain the stability of flame retardancy efficiency, dielectric response and mechanical strength under long-term complex working conditions. Specific embodiments

[0019] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative work fall within the scope of protection of the present invention.

[0020] Unless otherwise specified, the raw materials used in the present invention are all conventional products purchased from the market.

[0021] Preparation Example 1 The copolyamide nylon is prepared by the following steps: S1. Add 58 g of caprolactam and 0.5 g of sodium hydroxide into a reactor. Under nitrogen protection, heat up to 250 °C, stir and react at a speed of 200 rpm for 2 h, add 10 wt% acetic anhydride to terminate the reaction, continue stirring for 30 min, cool the system to 80 °C, dissolve 5.2 g of methacryloyl chloride in 20 g of dimethyl sulfoxide to prepare a methacryloyl chloride solution, dropwise add the methacryloyl chloride solution to the system, and at the same time add 4 g of triethylamine, react for 4 h, pour the product into ice water for precipitation, filter, wash with ethanol 3 times, and dry at 60 °C for 12 h to obtain V-PA6; S2. Add 64 g of V-PA6 and 36 g of allyl diethyl phosphonate to a reactor pre-filled with 100 g of N,N-dimethylformamide. Add 1.2 g of diisopropylbenzene peroxide. Under nitrogen protection, heat to 85 °C for the first time and stir the reaction at a speed of 100 rpm for 2 h. Then heat to 100 °C for the second time, add the remaining 0.8 g of diisopropylbenzene peroxide, and continue to stir the reaction at a speed of 100 rpm for 2 h. After the reaction is completed, cool to room temperature, pour the remaining material into ice methanol for precipitation, filter, wash with methanol 3 times, and dry at 60 °C for 24 h to obtain the copolyamide nylon.

[0022] Preparation Example 2 The copolyamide nylon is prepared by the following steps: S1. Add 59 g of caprolactam and 0.55 g of sodium hydroxide to a reactor. Under nitrogen protection, heat to 255 °C and stir the reaction at a speed of 250 rpm for 2.5 h. Add 10 wt% acetic anhydride to terminate the reaction, continue to stir for 35 min, cool the system to 82 °C. Dissolve 5.4 g of methacryloyl chloride in 22 g of dimethyl sulfoxide to prepare a methacryloyl chloride solution. Dropwise add the methacryloyl chloride solution to the system while adding 4.2 g of triethylamine, and react for 5 h. Pour the product into ice water for precipitation, filter, wash with ethanol 3 times, and dry at 60 °C for 12 h to obtain V-PA6; S2. Add 65 g of V-PA6 and 37 g of allyl diethyl phosphonate to a reactor pre-filled with 125 g of N,N-dimethylformamide. Add 1.6 g of diisopropylbenzene peroxide. Under nitrogen protection, heat to 87 °C for the first time and stir the reaction at a speed of 150 rpm for 2.5 h. Then heat to 105 °C for the second time, add the remaining 0.9 g of diisopropylbenzene peroxide, and continue to stir the reaction at a speed of 150 rpm for 2.5 h. After the reaction is completed, cool to room temperature, pour the remaining material into ice methanol for precipitation, filter, wash with methanol 3 times, and dry at 60 °C for 24 h to obtain the copolyamide nylon.

[0023] Preparation Example 3 The copolyamide nylon is prepared by the following steps: S1. Add 60 g of caprolactam and 0.6 g of sodium hydroxide to a reactor. Under nitrogen protection, heat to 260 °C and stir the reaction at a speed of 300 rpm for 3 h. Add 10 wt% acetic anhydride to terminate the reaction, continue to stir for 40 min, cool the system to 85 °C. Dissolve 5.6 g of methacryloyl chloride in 25 g of dimethyl sulfoxide to prepare a methacryloyl chloride solution. Dropwise add the methacryloyl chloride solution to the system while adding 4.3 g of triethylamine, and react for 6 h. Pour the product into ice water for precipitation, filter, wash with ethanol 3 times, and dry at 60 °C for 12 h to obtain V-PA6; S2. Add 66 g of V-PA6 and 38 g of allyl diethyl phosphonate to a reactor pre-filled with 150 g of N,N-dimethylformamide. Add 2.1 g of diisopropylbenzene peroxide. Under nitrogen protection, heat to 90 °C for the first time and stir the reaction at a speed of 200 rpm for 3 h. Then heat to 110 °C for the second time, add the remaining 0.9 g of diisopropylbenzene peroxide, and continue to stir the reaction at a speed of 200 rpm for 3 h. After the reaction is completed, cool to room temperature. Pour the remaining material into ice methanol for precipitation. Filter and wash with methanol 3 times. Dry at 60 °C for 24 h to obtain the copolyamide nylon.

[0024] Example 1 A method for preparing a flame-retardant high-dielectric lightweight nylon material, comprising the following steps: Add 75% of the copolyamide nylon prepared in Preparation Example 1, 4.5% of melamine cyanurate, 7% of barium titanate, 8% of hollow glass microspheres, 1.5% of KH-550, 0.8% of polyvinylpyrrolidone, 0.4% of antioxidant 1010, and 0.8% of ethylene bis-stearamide into a mixer according to mass percentage, mix at a speed of 2000 rpm for 10 min, load into a twin-screw extruder, the granulation temperature is 240 °C, the screw speed is 100 rpm, the extruded strip is water-cooled and pelletized, and the pellets with a diameter of 3 mm are obtained after pelletization. Injection molding is carried out to obtain 100 g of the flame-retardant high-dielectric lightweight nylon material.

[0025] Example 2 A method for preparing a flame-retardant high-dielectric lightweight nylon material, comprising the following steps: Add 73% of the copolyamide nylon prepared in Preparation Example 2, 6% of melamine cyanurate, 6% of barium titanate, 7% of hollow glass microspheres, 2% of KH-560, 1% of polyvinylpyrrolidone, 0.5% of antioxidant 1098, and 0.5% of stearamide into a mixer according to mass percentage, mix at a speed of 2500 rpm for 15 min, load into a twin-screw extruder, the granulation temperature is 242 °C, the screw speed is 150 rpm, the extruded strip is water-cooled and pelletized, and the pellets with a diameter of 3 mm are obtained after pelletization. Injection molding is carried out to obtain 100 g of the flame-retardant high-dielectric lightweight nylon material.

[0026] Example 3 A method for preparing a flame-retardant high-dielectric lightweight nylon material, comprising the following steps: By mass percentage, 74% of the copolymer nylon prepared in Preparation Example 3, 3% of melamine cyanurate, 8% of barium titanate, 8% of hollow glass microspheres, 1% of KH-570, 0.5% of polyvinylpyrrolidone, 0.3% of antioxidant 245 and 0.2% of polydimethylsiloxane were added to a mixer and mixed at a speed of 3000 rpm for 20 min, then loaded into a twin-screw extruder. The granulation temperature was 245 °C, the screw speed was 200 rpm, the extruded strip was cooled by water and cut into pellets. After cutting, pellets with a diameter of 3 mm were obtained and injection molded to obtain 100 g of flame-retardant high-dielectric lightweight nylon material.

[0027] Comparative Example 1 The difference between this comparative example and Example 1 is that commercially available PA6 was used instead of the copolymer nylon prepared in Preparation Example 1, and the remaining steps were the same as those in Example 1.

[0028] Comparative Example 2 The difference between this comparative example and Example 2 is that V-PA6 in Preparation Example 2 was used instead of the copolymer nylon, and the remaining steps were the same as those in Example 2.

[0029] Referring to ASTM D3801 "Standard Test Method for Measuring Comparative Combustion Characteristics of Solid Plastics in a Vertical Position", standard specimens (125×13×3 mm, 5 specimens in each group) were injection molded for Examples 1-3 and Comparative Examples 1-2 according to the same process. The specimens were conditioned in an environment at a temperature of 23±2 °C and a humidity of 50±5% for 48 h. The gas flow rate of the Bunsen burner was adjusted so that the height of the blue flame was 20±1 mm, and the flame height was measured and fixed with a flame height gauge. The specimen was vertically fixed to a metal fixture, and the bottom was 300 mm from the absorbent cotton layer. The lower center position of the specimen was contacted with the outer flame of the flame for 10 seconds, then the flame was removed until the flame self-extinguished, and the first ignition combustion time t1 was recorded. If the specimen reignited after self-extinguishing, the above operation was repeated, and the second combustion time t2 was recorded. Observe whether the dripping ignited the absorbent cotton below. The rating criteria are set as follows: V0 grade: single combustion time ≤ 10 s, total combustion time ≤ 50 s, no dripping ignition; V1 grade: single combustion time ≤ 30 s, total combustion time ≤ 250 s, no dripping ignition; V2 grade: total combustion time ≤ 250 s, dripping ignition is allowed; unrated: exceeding the above time or burning to the fixture. The results are shown in Table 1: Table 1. Flame Retardancy Test Results of Examples 1-3 and Comparative Examples 1-2

[0030] Refer to ASTM D150 "Standard Test Method for Permittivity (Dielectric Constant)", cut the splines of Examples 1-3 and Comparative Examples 1-2 into 100×100×2 mm squares, and use 2000-mesh sandpaper to polish the edges to remove burrs, and measure the thickness (take the average value at least at 5 points, record as d, unit: mm). Place the splines in a constant temperature drying oven at 50 °C for dehydration for 24 h, transfer them to a desiccator and cool to room temperature. Use a mask plate to coat the center area of the splines with aluminum to form a circular electrode with a diameter of 20 mm. The coating parameters are a vacuum degree ≤ 5×10 -3 Pa, the sputtering power is 200 W, and the coating time is 3 min. Measure the resistance between the electrodes with a multimeter to ensure that the resistance value > 10 12 Ω and there is no short circuit. Preheat the impedance analyzer for 30 min for calibration. Place each spline on an insulation test bench, make the electrode contact with the probe of the impedance analysis instrument, and use a spring clamp to ensure uniform pressure. The test mode is a parallel equivalent circuit, the test frequency is 1 kHz, and the test voltage is 1 V. Repeat the measurement 3 times at each frequency point, and take the average value of capacitance (C) and loss tangent (tanδ). Calculate the dielectric constant (ε), , ε0 = 8.854×10 −12 F / m, A = πr 2 = π(10×10 −3 ) 2 m 2 , and directly read the tanδ value as the dielectric loss (D). The results are shown in Table 2: Table 2. Dielectric Property Test Results of Examples 1-3 and Comparative Examples 1-2

[0031] As can be seen from Table 1, the total combustion time of Examples 1-3 is all < 50 s, there is no dripping ignition, and it reaches V0 level. It shows that the phosphonate groups in the copolyamide nylon may form a phosphorus-nitrogen synergistic flame retardant system with melamine cyanurate, effectively isolating heat and oxygen. In Comparative Example 1, the combustion reached the fixture without rating, and the dripping ignition rate was 100%. It shows that without introducing a flame retardant and polar groups, PA6 itself is flammable and has serious melting and dripping. The total combustion time of Comparative Example 2 is 165.4 ± 8.2 s, only reaching V2 level. It shows that although V-PA6 contains methacryloyl groups, it does not graft allyl diethyl phosphonate through Step S2, resulting in poor dispersibility of the flame retardant.

[0032] As can be seen from Table 2, the dielectric constants of Examples 1-3 are significantly higher than those of the comparative examples, and increase with the increase of the barium titanate content. It shows that the phosphonate groups in the copolyamide nylon enhance the molecular chain polarity and promote interfacial polarization. The high-dielectric filler improves the overall ε, and the 8% content in Example 3 combined with silver-plated microbeads may form a micro-capacitance network, further amplifying the polarization effect. The tanδ of Example 1 = 2.1×10 -3, indicating that the KH-550 coupling agent effectively improves the dispersion of barium titanate and reduces the leakage current; in Example 3, due to the introduction of the conductive phase (silver-plated microbeads), tanδ increased to 5.2×10 -3 , but it is still better than the comparative example. For Comparative Example 1, ε = 3.9 and tanδ = 9.2×10 -3 . It shows that the molecular chain of PA6 has weak polarity, and the hygroscopicity leads to an increase in loss. For Comparative Example 2, ε = 7.4 and tanδ = 6.8×10 -3 . It shows that the methacryloyl group imparts a certain polarity, but the lack of grafted phosphonate results in poor filler-matrix interfacial bonding, and the agglomeration of barium titanate causes local leakage. The phosphonate group not only improves the flame retardancy but also enhances the polarity, but excessive amount may increase the dielectric loss (the tanδ of Example 2 is slightly higher than that of Example 1).

[0033] In summary, the nylon materials prepared in Examples 1-3 have good flame retardancy and high dielectric properties.

[0034] In the description of the specification, the descriptions referring to terms such as "preparation example", "example", "each example", etc. mean that the specific features, structures, materials or characteristics described in connection with that example or preparation example are included in at least one example or preparation example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same example or preparation example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more examples or preparation examples.

[0035] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A flame-retardant, high-dielectric lightweight nylon material, characterized in that, It includes the following raw materials by mass percentage: Copolyamide nylon 70 - 80%, melamine cyanurate 3 - 6%, barium titanate 6 - 8%, hollow glass microspheres 5 - 10%, silane coupling agent 1 - 2%, polyvinylpyrrolidone 0.5 - 1%, antioxidant 0.3 - 0.5% and lubricant 0.2 - 1%.

2. A flame-retardant high-dielectric lightweight nylon material according to claim 1, characterized in that, The copolyamide nylon is prepared through the following steps: S1. Add caprolactam and sodium hydroxide into a reactor. Under nitrogen protection, raise the temperature and stir for reaction for 1.5 - 2.5 h, terminate the reaction, continue stirring for 30 - 40 min, cool down the system, dropwise add a methylacryloyl chloride solution pre - dissolved in dimethyl sulfoxide, and simultaneously add triethylamine. React for 4 - 6 h, precipitate, filter, wash, and dry to obtain V - PA6; S2. Add V - PA6 and allyl diethyl phosphonate into a reactor pre - filled with N,N - dimethylformamide, add a part of diisopropylbenzene peroxide. Under nitrogen protection, raise the temperature for the first time and stir for reaction for 2 - 3 h, raise the temperature for the second time, supplement the remaining diisopropylbenzene peroxide, and continue stirring for reaction for 2 - 3 h. After the reaction ends, cool to room temperature, precipitate, filter, wash, and dry to obtain the copolyamide nylon.

3. A flame-retardant high-dielectric lightweight nylon material according to claim 1, characterized in that, The silane coupling agent includes one or more of KH - 550, KH - 560, KH - 570, A - 172, and Si - 69.

4. A flame-retardant high-dielectric lightweight nylon material according to claim 1, characterized in that, The antioxidant includes one or more of antioxidant 1010, antioxidant 1098, antioxidant 245, antioxidant 168, and antioxidant 2246.

5. A flame-retardant high-dielectric lightweight nylon material according to claim 1, characterized in that, The lubricant includes one or more of ethylene bisstearamide, stearic acid amide, polydimethylsiloxane, pentaerythritol stearate, and polyethylene wax.

6. A flame-retardant high-dielectric lightweight nylon material according to claim 2, characterized in that Furthermore, in step S1, the mass ratio of caprolactam, sodium hydroxide, dimethyl sulfoxide, methylacryloyl chloride solution, and triethylamine is (58 - 60):(0.5 - 0.6):(20 - 25):(5.2 - 5.6):(4.0 - 4.3).

7. A flame-retardant high-dielectric lightweight nylon material according to claim 2, characterized in that, In step S1, the temperature for raising the temperature is 250 - 260 °C, the stirring speed is 200 - 300 rpm, and the temperature for cooling down is 80 - 85 °C.

8. A flame-retardant high-dielectric lightweight nylon material according to claim 2, characterized in that In step S2, the mass ratio of V - PA6, allyl diethyl phosphonate, N,N - dimethylformamide, and diisopropylbenzene peroxide is (64 - 66):(36 - 38):(100 - 150):(2 - 3), where the first addition amount of diisopropylbenzene peroxide is 60 - 70% of the total mass of diisopropylbenzene peroxide, and the remaining 30 - 40% is supplemented in the second temperature - raising stage.

9. A flame-retardant high-dielectric lightweight nylon material according to claim 2, characterized in that, In step S2, the temperature for the first temperature - raising is 85 - 90 °C, the temperature for the second temperature - raising is 100 - 110 °C, and the stirring speed is 100 - 200 rpm.

10. A method for preparing a flame-retardant high-dielectric lightweight nylon material according to any one of claims 1-9, characterized in that, It includes the following steps: Add copolyamide, melamine cyanurate, barium titanate, hollow glass microspheres, silane coupling agent, polyvinylpyrrolidone, antioxidant and lubricant into a mixer according to mass percentage, mix at a speed of 2000 - 3000 rpm for 10 - 20 min, load into a twin-screw extruder, the granulation temperature is 240 - 245 °C, the screw speed is 100 - 200 rpm, cool and cut the extruded strip into pellets, and obtain pellets with a diameter of 3 mm after cutting. Then carry out injection molding to obtain the flame-retardant high-dielectric lightweight nylon material.

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