Polyamide composition, process for its preparation and use thereof

Abstract

The application discloses a polyamide composition and a preparation method and application thereof, and belongs to the field of high polymer materials. The polyamide composition utilizes an organic phosphine flame retardant and a flame retardant synergist to form a flame retardant system, and introduces aromatic polyamide and zirconium hydroxide to improve electrochemical corrosion resistance. Under the synergistic effect of the components, the composition has excellent mechanical properties, flame retardant properties and electrochemical corrosion resistance, especially high-temperature and high-humidity (such as 85 DEG C in temperature and 85% RH in humidity) electrochemical corrosion resistance, and has a very good application prospect in the fields of new energy high-voltage connectors, energy storage connectors and the like.

Description

Technical Field

[0001] This application relates to the field of polymer materials, specifically to a polyamide composition and its preparation method and application. Background Technology

[0002] Organophosphorus halogen-free flame-retardant polyamides are widely used in high-voltage connectors and energy storage connectors due to their excellent comprehensive mechanical properties, ease of coloring, ease of processing, and high CTI (Chemical Intensity Tolerance). However, as the application environments of connectors (such as high temperature and high humidity) become increasingly complex, the performance requirements for materials are constantly being upgraded. In particular, for high-voltage connectors and energy storage connectors, which involve high voltage, the electrochemical corrosion performance of materials under high temperature and high humidity environments is receiving increasing attention. Electrochemical corrosion leads to a decrease in the surface resistivity and insulation withstand voltage of the material, making it highly susceptible to breakdown and failure under high voltage or high current. Therefore, it is necessary to develop an organophosphorus halogen-free flame-retardant polyamide material that not only exhibits excellent electrochemical corrosion resistance under high temperature and high humidity conditions but also possesses excellent mechanical properties and flame-retardant properties. Summary of the Invention

[0003] Based on the deficiencies of the existing technology, the purpose of this application is to provide a polyamide composition, its preparation method and application, so as to improve the electrochemical corrosion resistance of the polyamide composition, especially the electrochemical corrosion resistance under high temperature and high humidity (e.g., temperature 85℃, humidity 85%RH) conditions, and to make it have excellent mechanical properties and flame retardant properties.

[0004] To achieve the above objectives, in a first aspect, this application provides a polyamide composition comprising the following components in parts by weight:

[0005]

[0006] The polyamide resin includes a semi-aromatic polyamide resin;

[0007] In the polyamide resin, the weight percentage of the semi-aromatic polyamide resin is ≥14%.

[0008] The organophosphorus flame retardants and flame retardant synergists used in organophosphorus halogen-free flame-retardant polyamide materials are usually highly acidic, which will promote the hydrolysis of polyamide. Moreover, they are prone to decomposition during high-temperature processing. The small molecules produced by decomposition are easily precipitated on the material surface under high temperature and high humidity conditions. At the same time, the ions in the material are prone to form galvanic cell reactions. All of these factors will accelerate the electrochemical corrosion of the material. During their research, the inventors discovered that the benzene ring of semi-aromatic polyamide resin not only possesses barrier properties, but its π-π structure can also interact with cations, thereby reducing the number of free ions in the system. Compared to other alkaline substances, such as oxides like magnesium oxide, aluminum oxide, zinc oxide, and zirconium oxide, as well as hydroxides like magnesium hydroxide, aluminum hydroxide, zinc hydroxide, and boehmite, zirconium hydroxide can significantly improve the electrochemical corrosion performance of the material. This may be because zirconium hydroxide has good stability and compatibility with the matrix resin, and it also exhibits strong selectivity for phosphate ions, allowing it to coat phosphate ions and greatly reduce electrochemical corrosion. By introducing semi-aromatic polyamide resin and zirconium hydroxide, and limiting the dosage of each component within a specific range, the resulting polyamide composition can possess excellent mechanical properties (notched impact strength of simply supported beams, etc.), flame retardant properties, and electrochemical corrosion resistance, especially under high temperature and high humidity conditions (e.g., temperature 85℃, humidity 85%RH).

[0009] In the polyamide resin, the weight percentage of the semi-aromatic polyamide resin is ≥14%, such as 14%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 100%, or any two of the above values ​​forming a range.

[0010] Preferably, the weight ratio of the semi-aromatic polyamide resin to the zirconium hydroxide is (35-130):1. More preferably, the weight ratio of the semi-aromatic polyamide resin to the zirconium hydroxide is (48-102):1.

[0011] When the weight ratio of the semi-aromatic polyamide resin to the zirconium hydroxide is in the range of (35–130):1, and especially in the range of (48–102):1, the resulting composition exhibits better electrochemical corrosion performance. The weight ratio of the semi-aromatic polyamide resin to the zirconium hydroxide can be selected from any two of the following ranges: 35:1, 40:1, 45:1, 50:1, 55:1, 60:1, 65:1, 70:1, 75:1, 80:1, 85:1, 90:1, 95:1, 100:1, 105:1, 110:1, 115:1, 120:1, 125:1, 130:1, or any range formed by two of these values.

[0012] Preferably, the average particle size of the zirconium hydroxide is 0.5-4 μm. For example, the average particle size of the zirconium hydroxide is within the range formed by any two of the following values: 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 4 μm.

[0013] When the average particle size of the zirconium hydroxide is in the range of 0.5-4 μm, the resulting polyamide composition has good mechanical properties, such as higher notched impact strength of simply supported beams.

[0014] The average particle size (Dv50) of the zirconium hydroxide can be measured using a laser particle size analyzer according to GB / T 19077-2016.

[0015] Preferably, the relative viscosity of the concentrated sulfuric acid solution of the aromatic polyamide at 25°C is 2.0 to 2.7, wherein the concentration of aromatic polyamide in the concentrated sulfuric acid solution is 0.01 g / mL and the concentration of H2SO4 is 96 wt.%.

[0016] When the relative viscosity of the concentrated sulfuric acid solution of the aromatic polyamide at 25°C is in the range of 2.0 to 2.7, such as 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7 or any two of the above values, it is more conducive to the balance between the material's mechanical properties (such as the notched impact strength of a simply supported beam) and processing performance.

[0017] Preferably, the semi-aromatic polyamide resin includes at least one of PA6T, PA9T, PA10T, PA12T, and nylon MXD6. More preferably, the semi-aromatic polyamide resin includes nylon MXD6. Nylon MXD6 has a lower melting point and better processing performance.

[0018] Preferably, the polyamide resin further includes an aliphatic polyamide resin, and the weight ratio of the semi-aromatic polyamide resin to the weight ratio of the aliphatic polyamide resin is ≥ 1 / 6. More preferably, the weight ratio of the semi-aromatic polyamide resin to the weight ratio of the aliphatic polyamide resin is 1 / 6 to 7 / 1.

[0019] Compared to semi-aromatic polyamide resins, aliphatic polyamide resins are cheaper. Controlling the weight ratio of semi-aromatic polyamide resin to aliphatic polyamide resin to be ≥1 / 6, especially in the range of 1 / 6 to 7 / 1, yields a more cost-effective polyamide composition. The weight ratio of semi-aromatic polyamide resin to aliphatic polyamide resin can be selected from any two values ​​within a range of 1 / 6, 1 / 5, 1 / 4, 1 / 3, 1 / 2, 1 / 1, 2 / 1, 3 / 1, 4 / 1, 5 / 1, 6 / 1, 7 / 1, 8 / 1, 9 / 1, 10 / 1, 20 / 1, 40 / 1, 60 / 1, 80 / 1, 100 / 1, 500 / 1, 1000 / 1, or more.

[0020] Preferably, the relative viscosity of the concentrated sulfuric acid solution of the aliphatic polyamide resin at 25°C is 1.9 to 2.5, wherein the concentration of aliphatic polyamide in the concentrated sulfuric acid solution is 0.01 g / mL and the concentration of H2SO4 is 96 wt.%.

[0021] When the relative viscosity of the concentrated sulfuric acid solution of the aliphatic polyamide resin at 25°C is in the range of 1.9 to 2.5, such as 2.0, 2.1, 2.2, 2.3, 2.4, 2.5 or any two of the above values, it is more conducive to the balance between the material's mechanical properties (such as the notched impact strength of a simply supported beam) and processing performance.

[0022] The relative viscosity of the semi-aromatic polyamide resin in concentrated sulfuric acid solution at 25°C and the relative viscosity of the aliphatic polyamide resin in concentrated sulfuric acid solution at 25°C can be measured by the following method: 0.5g of polyamide resin is added to a 50mL volumetric flask, and about 40mL of 96wt.% concentrated sulfuric acid is added. The mixture is ultrasonically vibrated until the polyamide resin is completely dissolved. The solution is cooled to 25°C, diluted to the mark with 96wt.% concentrated sulfuric acid, mixed and dispersed to obtain a polyamide resin solution with a concentration of 0.01g / mL. The flow time of this solution through an Ubbelohde viscometer at 25°C is measured and recorded as t1. The flow time of the solvent 96wt.% concentrated sulfuric acid is measured using the same viscometer and recorded as t2. t1 / t2 is the relative viscosity of the polyamide resin.

[0023] Preferably, the aliphatic polyamide resin comprises at least one selected from the condensation products of one or more dicarboxylic acids and one or more diamines, the condensation products of two or more aminocarboxylic acids, and the ring-opening polymerization products of one or more lactams. More preferably, the aliphatic polyamide resin comprises polyhexamethylene adipamide (i.e., PA66).

[0024] Preferably, the organophosphorus flame retardant comprises aluminum diethylphosphonate. Compared to other organophosphorus flame retardants, aluminum diethylphosphonate offers better cost-effectiveness.

[0025] Preferably, the flame retardant synergist includes at least one of melamine polyphosphate, melamine aluminum polyphosphate, melamine magnesium polyphosphate, melamine zinc polyphosphate, and zinc borate. More preferably, the flame retardant synergist includes melamine polyphosphate to reduce costs.

[0026] Preferably, the glass fiber includes at least one of A glass fiber (high alkali glass fiber), C glass fiber (medium alkali glass fiber), D glass fiber, E glass fiber (alkali-free glass fiber), S glass fiber (special glass fiber), and quartz glass fiber.

[0027] Preferably, the glass fiber has an average diameter of 10-13 μm and an average aspect ratio of 280-330.

[0028] Without compromising the technical effect of this application, the polyamide composition may also contain at least one of antioxidants and lubricants, such as at least one of antioxidant 1098, montan ester, etc.

[0029] Preferably, the polyamide composition contains 30% or more of the polyamide resin (i.e., all of the polyamide resin) by weight, such as within the range formed by any two values ​​of 30%, 40%, 50%, 60%, 70%, 79%, or more.

[0030] Secondly, this application provides a method for preparing the polyamide composition, comprising the following steps:

[0031] All raw materials are mixed and dispersed, melt-extruded, and granulated to obtain a polyamide composition.

[0032] Preferably, the melt extrusion is carried out in a twin-screw extruder with a length-to-diameter ratio of 36:1 to 48:1, a screw speed of 300 to 800 rpm, an independent barrel temperature of 160°C to 330°C for each section, and a die head temperature of 280°C to 330°C.

[0033] Thirdly, this application provides the use of the polyamide composition in high-voltage connectors or energy storage connectors. In some embodiments, the high-voltage connector operates at 800V.

[0034] Compared with the prior art, the beneficial effects of this application are as follows: The polyamide composition of this application utilizes organophosphorus flame retardants and flame retardant synergists to form a flame retardant system, and introduces aromatic polyamides and zirconium hydroxide to improve electrochemical corrosion resistance. Under the synergistic effect of each component, the composition has excellent mechanical properties (notched impact strength of simply supported beams, etc.), flame retardant properties and electrochemical corrosion resistance, especially the electrochemical corrosion resistance under high temperature and high humidity conditions (such as temperature 85℃ and humidity 85%RH), which has very good application prospects in the fields of new energy high voltage connectors and energy storage connectors. Attached Figure Description

[0035] Figure 1 The reference diagram for evaluating electrochemical corrosion resistance is shown (from left to right: no corrosion, slight corrosion, corrosion, severe corrosion). Detailed Implementation

[0036] To better illustrate the purpose, technical solutions, and advantages of this application, the following description, in conjunction with specific embodiments and comparative examples, aims to provide a detailed understanding of the content of this application, rather than limiting it. All other embodiments obtained by those skilled in the art without inventive effort are within the protection scope of this application. Unless otherwise specified, the experimental reagents and instruments involved in the implementation of this application are commonly used reagents and instruments. In this application, the technical features described in an open-ended manner include both closed-ended technical solutions composed of the listed features and open-ended technical solutions that include the listed features.

[0037] The following examples and comparative examples all provide a polyamide composition. The formulations of these polyamide compositions are shown in Tables 1 and 2. Their preparation methods include the following steps: after mixing and dispersing all raw materials, they are fed into a twin-screw extruder and granulated to obtain a polyamide composition. The twin-screw extruder has an aspect ratio of 48:1, a screw speed of 400 rpm, and the temperature of each section of the barrel is independently 160℃~330℃, while the die head temperature is 290℃~320℃.

[0038] The raw materials used in the above embodiments and comparative examples are shown below. Unless otherwise specified, all raw materials are commercially available. In addition, the component raw materials used in each parallel experiment are the same:

[0039] Semi-aromatic polyamide resin 1: Nylon MXD6, its relative viscosity in concentrated sulfuric acid solution at 25℃ is 2.2, model PA MXD6 M30L, manufacturer Beijing Anaiji Energy Engineering Technology Co., Ltd.;

[0040] Semi-aromatic polyamide resin 2: PA6T, its relative viscosity of concentrated sulfuric acid solution at 25℃ is 2.2, model KFHP41, manufacturer Zhuhai Wantong Special Engineering Plastics Co., Ltd.;

[0041] Semi-aromatic polyamide resin 3: PA9T, its relative viscosity in concentrated sulfuric acid solution at 25℃ is 2.2, model N1000A-M41, manufacturer Kuraray Trading (Shanghai) Co., Ltd.;

[0042] Semi-aromatic polyamide resin 4: PA10T, its relative viscosity of concentrated sulfuric acid solution at 25℃ is 2.1, model KFHP611, manufacturer Zhuhai Wantong Special Engineering Plastics Co., Ltd.;

[0043] Semi-aromatic polyamide resin 5: PA12T, its relative viscosity of concentrated sulfuric acid solution at 25℃ is 2.1, model PA12T 20N 00, manufacturer Henan Junheng Industrial Group Biotechnology Co., Ltd.;

[0044] Aliphatic polyamide resin 1: PA66, its relative viscosity in concentrated sulfuric acid solution at 25℃ is 2.0, model PA66U2501, manufacturer Invista Nylon Chemical (China) Co., Ltd.;

[0045] Aliphatic polyamide resin 2: PA56, its relative viscosity in concentrated sulfuric acid solution at 25℃ is 2.2, model PA56E-2260, manufacturer Kaisai (Wusu) Biomaterials Co., Ltd.;

[0046] Aliphatic polyamide resin 3: PA610, its relative viscosity in concentrated sulfuric acid solution at 25℃ is 2.0, model PA610F120, manufacturer Shandong Guangyin New Material Co., Ltd.;

[0047] Aluminum diethylphosphinic acid: Model: Exolit OP 1230, Manufacturer: Clariant International AG;

[0048] Flame retardant synergist 1: melamine polyphosphate, model Bubit 3141, manufacturer BUDENHEIMIBERICA, SLU;

[0049] Flame retardant synergist 2: Zinc melamine polyphosphate, model Safire 400, manufacturer HUBERADVANCEDMATERIALS;

[0050] Flame retardant synergist 3: Zinc borate, model ZB-503, manufactured by Anhui Yishitong Materials Technology Co., Ltd.

[0051] Glass fiber: E glass fiber, average diameter 10μm, average aspect ratio 300, model ECS10-03-568H, manufacturer: China Jushi Co., Ltd.

[0052] Zirconium hydroxide 1: average particle size 1.0 μm, self-made;

[0053] Zirconium hydroxide 2: average particle size 2.2 μm, self-made;

[0054] Zirconium hydroxide 3: average particle size 3.0 μm, self-made;

[0055] Magnesium oxide: average particle size 1.5μm, manufacturer: Shandong Ocean Star Chemical Technology Co., Ltd.

[0056] Zirconia: average particle size 1.6 μm, self-made;

[0057] Magnesium hydroxide: average particle size 1μm, model Aitemag 12FD, manufacturer Jiangsu Aitemag Flame Retardant Materials Co., Ltd.;

[0058] Boehmite: average particle size 1.5μm, model BG-613SO, manufacturer Anhui Yishitong Materials Technology Co., Ltd.

[0059] The method for testing the relative viscosity of the above-mentioned semi-aromatic polyamide resins and aliphatic polyamide resins in concentrated sulfuric acid solutions at 25°C is as follows: Add 0.5g of polyamide resin to a 50mL volumetric flask, add about 40mL of 96wt.% concentrated sulfuric acid, and sonicate until the polyamide resin is completely dissolved. Cool the solution to 25°C, dilute to the mark with 96wt.% concentrated sulfuric acid, mix and disperse to obtain a polyamide resin solution with a concentration of 0.01g / mL. Test the flow time of this solution through an Ubbelohde viscometer at 25°C, and record it as t1; use the same viscometer to test the flow time of the solvent 96wt.% concentrated sulfuric acid, and record it as t2. t1 / t2 is the relative viscosity of the polyamide resin.

[0060] The above-mentioned method for preparing zirconium oxide is as follows: Zirconium oxide coarse powder (average particle size 7μm) is provided, which is purchased from Xi'an Fangke New Material Technology Co., Ltd.; after grinding with a planetary ball mill, it is sieved through an 8000-mesh sieve to obtain zirconium oxide fine powder with an average particle size of 1.6μm.

[0061] The above-mentioned method for preparing zirconium hydroxide is as follows: Zirconium hydroxide (model: TZH-85H; average particle size 25μm) was purchased from Qingdao Tianyao Industrial Co., Ltd.; after grinding with a planetary ball mill, it was sieved through 11000 mesh, 6000 mesh and 4000 mesh sieves respectively to obtain zirconium hydroxide fine powder with average particle sizes of 1.0μm, 2.2μm and 3.0μm.

[0062] The polyamide compositions of the above examples and comparative examples were subjected to the following performance tests:

[0063] 1) Surface exudation: Place a 100*100*3mm sample in an environmental chamber at 85℃ and 85%RH for 500 hours. Visually evaluate the state of the surface exudates. According to the degree of exudation, it is divided into no exudation, slight exudation (point-like exudation), exudation (linear exudation), and severe exudation (area-like exudation) from light to heavy.

[0064] 2) Electrochemical corrosion resistance: A cylindrical copper wire with a diameter of 1 cm was inserted into the polyamide composition. A voltage of 1 kV was applied, and the apparatus was placed in an environmental chamber at 85°C and 85% RH for 500 hours. At the end of the experiment, the electrochemical corrosion resistance was evaluated by assessing the degree of corrosion on the copper wire surface in contact with the polyamide composition. (Reference) Figure 1 According to the degree of corrosion, it is divided into four levels from light to severe: no corrosion, slight corrosion, corrosion, and severe corrosion.

[0065] 3) The flame retardancy rating test is conducted in accordance with the UL 94 standard, and the test strip size is 125mm*13mm*1.6mm;

[0066] 4) Impact performance of simply supported beams with notched sections: according to ISO 179-1:2010 method, the test specimen size is 80*10*4mm, with a type A notch.

[0067] The test results are shown in Table 3.

[0068] Table 1

[0069]

[0070] Table 2

[0071]

[0072]

[0073] Table 3

[0074]

[0075] As can be seen from the above data, the compositions of each embodiment possess excellent mechanical properties (notched impact strength of simply supported beams, etc.), flame retardant properties, resistance to damp heat, and resistance to electrochemical corrosion, especially the resistance to electrochemical corrosion under high temperature and high humidity conditions (e.g., temperature 85°C, humidity 85%RH). The notched impact strength of simply supported beams is 10 J / m. 2 The flame retardant rating is above V-0. Under conditions of 85℃ and 85%RH for 500 hours, there is no or slight precipitation on the surface. Under conditions of 85℃, 85%RH and 1kV for 500 hours, there is no or slight corrosion on the surface.

[0076] As can be seen from the comparison between Examples 1, 8-11 and Comparative Example 1, the use of semi-aromatic polyamide resin is beneficial to improving the electrochemical corrosion performance of the material compared to aliphatic polyamide resin.

[0077] A comparison of Examples 1 and 15-16 with Comparative Examples 2 and 4-7 shows that adding zirconium hydroxide as an electrochemical stabilizer significantly improves the electrochemical corrosion resistance of the material while maintaining high mechanical properties and good flame retardancy. Adding oxides such as magnesium oxide and zirconium oxide does not significantly improve the electrochemical corrosion resistance because these oxides have poor compatibility with the matrix resin, and zirconium oxide's high hardness can abrade glass fibers, thus significantly affecting the material's mechanical properties. Adding hydroxides such as magnesium hydroxide is also ineffective because these hydroxides are easily decomposed and have little effect on improving electrochemical corrosion resistance. Adding boehmite has a weak effect on improving electrochemical corrosion resistance because boehmite mainly utilizes its porous structure to absorb acid. A comparison of Examples 1-7 with Comparative Example 3 shows that the amount of zirconium hydroxide added should not be too high, otherwise it will weaken the product's toughness.

[0078] As can be seen from the comparison of Examples 1, 4 to 7, when the total amount of aromatic polyamide and zirconium hydroxide added is constant, and when the weight ratio of the two is in the range of (48 to 102):1, the comprehensive mechanical, damp heat resistance and electrochemical corrosion resistance of the product are better.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit the scope of protection of this application. Although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this application without departing from the substance and scope of the technical solutions of this application.

Claims

1. A polyamide composition, characterized in that, Includes the following components by weight: 28-72 parts of polyamide resin; 8-18 parts of organophosphorus flame retardant; 0.5-2 parts of flame retardant synergist; 10-40 parts glass fiber; Zirconium hydroxide 0.2~0.6 parts; The polyamide resin includes a semi-aromatic polyamide resin; In the polyamide resin, the weight percentage of the semi-aromatic polyamide resin is ≥14%; The weight ratio of the semi-aromatic polyamide resin to the zirconium hydroxide is (48~102):1; The polyamide resin further includes aliphatic polyamide resin, and the weight of the semi-aromatic polyamide resin / the weight of the aliphatic polyamide resin is ≥1 / 6.

2. The polyamide composition according to claim 1, characterized in that, The zirconium hydroxide has an average particle size of 0.5-4 μm.

3. The polyamide composition according to claim 1, characterized in that, The semi-aromatic polyamide resin satisfies at least one of the following conditions: S1. The relative viscosity of the concentrated sulfuric acid solution of the semi-aromatic polyamide resin at 25°C is 2.0~2.7, wherein the concentration of the semi-aromatic polyamide resin in the concentrated sulfuric acid solution is 0.01 g / mL, and the concentration of H2SO4 is 96 wt.%. S2. The semi-aromatic polyamide resin includes at least one of PA6T, PA9T, PA10T, PA12T, and Nylon MXD6.

4. The polyamide composition according to claim 1, characterized in that, The weight ratio of the semi-aromatic polyamide resin to the weight ratio of the aliphatic polyamide resin is 1 / 6 to 7 / 1.

5. The polyamide composition according to claim 1, characterized in that, The aliphatic polyamide resin satisfies at least one of the following conditions: S3. The relative viscosity of the aliphatic polyamide resin is 1.9~2.

5. The test method is to measure the relative viscosity of the aliphatic polyamide with a concentration of 0.01 g / mL in concentrated sulfuric acid at 25°C, wherein the concentration of H2SO4 in the concentrated sulfuric acid is 96 wt.%. S4. The aliphatic polyamide resin includes at least one of PA66, PA56, PA610, PA1212, and PA6.

6. The polyamide composition according to claim 1, characterized in that, The organophosphorus flame retardant includes aluminum diethylphosphonate; the flame retardant synergist includes at least one of melamine polyphosphate, melamine aluminum polyphosphate, melamine magnesium polyphosphate, melamine zinc polyphosphate, and zinc borate.

7. The polyamide composition according to claim 1, characterized in that, The glass fiber satisfies at least one of the following conditions: S5. The glass fiber includes at least one of A glass fiber, C glass fiber, D glass fiber, E glass fiber, S glass fiber, and quartz glass fiber; S6. The glass fiber has an average diameter of 10-13 μm and an average aspect ratio of 280-330.

8. The method for preparing the polyamide composition according to any one of claims 1 to 7, characterized in that, All raw materials are mixed and dispersed, melt-extruded, and granulated to obtain a polyamide composition.

9. The use of the polyamide composition according to any one of claims 1 to 7 in high-voltage connectors or energy storage connectors.

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