A polyamide composition, its preparation method and application

Abstract

This invention discloses a polyamide composition comprising, by weight, the following components: 55-80 parts of polyamide resin; 8-15 parts of melamine cyanurate; and 2-4 parts of chain extender. The polyamide resin is a blend of aromatic and aliphatic polyamide resins, and, based on the total weight percentage of repeating units in the polyamide resin, repeating units containing benzene rings account for 10-30 wt%; the concentration of terminal amines in the polyamide resin is 100-200 mmol / kg. The polyamide composition of this invention possesses advantages such as good flame retardancy, high temperature resistance, excellent dimensional stability, and chemical resistance, making it suitable for preparation in two core fields with stringent requirements for heat resistance, dimensional accuracy, and reliability: automotive (especially electrified and intelligent components) and electronic and electrical (especially miniaturized and high-frequency components).

Description

Technical Field

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

[0002] Polyamide (PA), as an important engineering plastic, is limited in its application in high-safety fields due to its flammability and tendency to melt and drip during combustion. Although traditional halogenated flame retardants are effective, they are gradually being phased out due to environmental concerns. Nitrogen-based flame retardants (MCA) have gained attention due to their environmentally friendly properties. These flame retardants mainly achieve flame retardancy by promoting polymer degradation, inducing dripping, and carrying away heat. However, this also leads to a significant decrease in thermal stability in nylon systems, creating an inherent contradiction between flame retardancy and thermal stability.

[0003] In the context of a circular economy, the high-value utilization of recycled polyamides is becoming increasingly important. However, after multiple processing steps, recycled polyamides are prone to molecular chain breakage and performance degradation, leading to a significant reduction in intrinsic thermal stability and chemical resistance. This poses a severe challenge to the development of flame-retardant recycled polyamide materials. Especially in nitrogen-based flame-retardant systems, relying solely on antioxidants and surface modification is insufficient to achieve ideal high-temperature stability and chemical resistance. This is because, on the one hand, MCA-type flame retardants are acidic and catalyze the degradation of polyamides under processing or high-temperature conditions; on the other hand, recycled polyamides have lower molecular weights and higher end-group content, further exacerbating the instability of the material under thermal and chemical influences. Therefore, balancing flame retardancy and thermal stability becomes crucial for their practical application.

[0004] It is worth noting that the terminal amino groups in recycled polyamides have a dual impact on material properties: the high content of terminal amino groups in recycled materials has a positive effect on thermal stability, but excessive terminal amino groups can interact with acidic MCA, thereby weakening the flame retardant efficiency. Furthermore, due to the short molecular chains of recycled materials, they have poor temperature resistance and chemical resistance. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned technical defects and provide a polyamide composition with good chemical resistance and flame retardant properties, as well as its preparation method and application.

[0006] This invention is achieved through the following technical solution:

[0007] A polyamide composition, by weight, comprises the following components:

[0008] 55-80 parts of polyamide resin;

[0009] 8-15 parts of melamine cyanurate;

[0010] Chain extender 2-4 parts;

[0011] The polyamide resin is a blend of aromatic and aliphatic polyamide resins, and the repeating units containing benzene rings account for 10-30 wt% of the total weight percentage of the repeating units in the polyamide resin.

[0012] The concentration of terminal amino groups in polyamide resin is 100-200 mmol / kg.

[0013] The sample was processed into a solid state. 13 12C NMR spectroscopy analysis was performed to acquire high-resolution spectra. The obtained spectra were compared with standard spectra of known aliphatic and aromatic polyamides, revealing differences in the chemical shift peak positions corresponding to hydrogen atoms in the aromatic ring and methylene hydrogen atoms in the aliphatic long chain. By comparing the integrated area of ​​specific aromatic proton peaks with the total aliphatic chain proton peaks, the mole fraction X of the aromatic structural unit in the entire molecular chain can be calculated. A Weight fraction W A The mole fraction can be multiplied by the molar mass of each mole and then divided by the total mass (the calculation formula is as follows).

[0014] W A = (X A ×M A ) ÷ (X A ×M A + X B ×M B ) × 100%, (X A M represents the mole fraction of aromatic structural units in the entire molecular chain. A Represents the molar mass of the aromatic structural unit, X B M represents the mole fraction of adipose structural units in the entire molecular chain. B (Represents the molar mass of a fatty structural unit).

[0015] In the polyamide composition of the present invention, the content of polyamide resin can be any value or a range between 56 parts, 57 parts, 58 parts, 59 parts, 60 parts, 61 parts, 62 parts, 63 parts, 64 parts, 65 parts, 66 parts, 67 parts, 68 parts, 69 parts, 70 parts, 71 parts, 72 parts, 73 parts, 74 parts, 75 parts, 76 parts, 77 parts, 78 parts, and 79 parts; the content of melamine cyanurate can be any value or a range between 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, and 15 parts; and the content of chain extender can be any value or a range between 2 parts, 2.5 parts, 3 parts, 3.5 parts, and 4 parts.

[0016] The percentage of repeating units containing benzene rings can be any value from 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt%, 20 wt%, 21 wt%, 22 wt%, 23 wt%, 24 wt%, 25 wt%, 26 wt%, 27 wt%, 28 wt%, 29 wt%, 30 wt%, or a range between the two. The concentration of terminal amines in the polyamide resin can be any value from 100 mmol / kg, 110 mmol / kg, 120 mmol / kg, 130 mmol / kg, 140 mmol / kg, 150 mmol / kg, 160 mmol / kg, 170 mmol / kg, 180 mmol / kg, 190 mmol / kg, 200 mmol / kg, or a range between the two.

[0017] The polyamide resin is derived from virgin or recycled polyamide resin. It is particularly suitable for recycled materials.

[0018] The polyamide resin is a blend of aromatic polyamide resin and aliphatic polyamide resin, and the repeating unit containing benzene ring accounts for 15-25 wt% of the total weight percentage of the repeating units of the polyamide resin.

[0019] The concentration of terminal amine groups in polyamide resin is 130-160 mmol / kg. The terminal amine content of polyamide resin is determined by acid-base titration. The terminal amine content of the sample is determined using a fully automated point titrator. The amount of polyamide resin is 0.5 g, 45 ml of phenol and 3 ml of anhydrous methanol are added, the mixture is heated under reflux to dissolve, insoluble matter is filtered off, and the terminal amine content is titrated with a standardized hydrochloric acid solution. The formula is: Terminal amine value (mmol / kg) = (C × V × 1000) / m; where C: hydrochloric acid concentration (mol / L); V: hydrochloric acid consumption volume (mL); m: sample mass (g); 1000: unit conversion factor (converting g to kg).

[0020] The chain extender is selected from at least one of the following: bis / polyepoxy functional group chain extenders, bis / polyoxazoline chain extenders, bis / polyanhydride chain extenders, and diisocyanate chain extenders.

[0021] The aforementioned dual / polyepoxy functional group chain extender is selected from one or more of 1,4-butanediol diglycidyl ether, trimethylolpropane triglycidyl ether, glycerol polyglycidyl ether, styrene-glyceryl acrylate copolymer, or ethylene-methyl acrylate-glycidyl methacrylate terpolymer.

[0022] The bis / polyoxazoline chain extender is selected from one or more of 1,3-phenylenebis(2-oxazoline), 1,2-phenylenebis(2-oxazoline), bis(2-oxazoline)alkane, poly(styrene-vinyl-2-oxazoline), or acrylate oxazoline copolymers;

[0023] The aforementioned bis / poly anhydride chain extender is selected from one or more of pyromellitic dianhydride, styrene-maleic anhydride copolymer, maleic anhydride-grafted polyolefin, or EPDM-grafted maleic anhydride.

[0024] The diisocyanate chain extender is selected from one or more of toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, or dicyclohexylmethane diisocyanate.

[0025] The aromatic polyamide resin is selected from at least one of fully aromatic polyamides and semi-aromatic polyamides; the fully aromatic polyamide is selected from PPTA, and the semi-aromatic polyamide is selected from at least one of PA6T, PA10T, PA6I / 6T, PA10T / 1012, PAMXD10, and PAMXD6; the aliphatic polyamide resin is selected from at least one of AB-type aliphatic polyamides prepared by ring opening of ω-amino acids or lactams, and aliphatic polyamides formed by condensation polymerization of diacids and diamines, wherein the AB-type aliphatic polyamide is selected from at least one of PA6, PA11, and PA12; the aliphatic polyamide formed by condensation polymerization of diacids and diamines is selected from at least one of PA66, PA612, PA610, PA1010, PA1012, and PA1212; the relative viscosity range of the aromatic polyamide resin is 1.0-4.0, and the relative viscosity range of the aliphatic polyamide resin is 1.0-4.0 (test standard is ISO 307:2019, sulfuric acid method).

[0026] 0-20 parts of additives can be added according to actual needs. The additives are selected from at least one of antioxidants, lubricants, and reinforcing fibers.

[0027] Antioxidants can be: bis(2,6-di-tert-butyl-4-tolyl) pentaerythritol phosphite; 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene; 2,5-di-tert-butyl-4-hydroxybenzyl dimethylamine; diethyl-3,5-di-tert-butyl-4-hydroxybenzyl phosphate; stearyl-3,5-di-tert-butyl-4-hydroxybenzyl phosphate; 3,5-di-tert-butyl-4-hydroxyphenyl-3,5-distearate-thiotriazolylamine; 2,6-di-tert-butyl-4-hydroxymethylphenol; 2,4-di-(n-octylthio)-6-(4-hydroxy-3,5-di-tert-butylglycerol allyl ether)-1,3,5-trimethyl-3-(2,6 ... Azides; N,N'-hexamethylene di(3,5-di-tert-butyl-4-hydroxy-hydrogenated cinnamamide); N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine; octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate; pentaerythritol-tetra[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]; triethylene glycol-di[3-(3,5-dimethyl-4-hydroxyphenyl)propionate]; triethylene glycol bis[β-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate]; 2,2'-thiodiethyl-di[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, etc.

[0028] The lubricant may be at least one of the following: stearate lubricant, fatty acid lubricant, and stearate ester lubricant; the stearate lubricant is selected from at least one of calcium stearate, magnesium stearate, and zinc stearate; the fatty acid lubricant is selected from at least one of fatty acids, fatty acid derivatives, and fatty acid esters; and the stearate ester lubricant is selected from pentaerythritol stearate.

[0029] The reinforcing fiber can be at least one of the following: glass fiber, carbon fiber, basalt fiber, and aramid fiber.

[0030] The method for preparing the polyamide composition of the present invention includes the following steps: mixing the components evenly according to the formula, and granulating the mixture by extrusion through a twin-screw extruder to obtain the polyamide composition. The twin-screw extruder has a screw length-to-diameter ratio of 40~48:1, a barrel temperature of 280~330℃, and a screw speed of 150~400 rpm.

[0031] The polyamide compositions of the present invention are used in the preparation of components for two core fields with stringent requirements for heat resistance, dimensional accuracy and reliability: automobiles (especially electrified and intelligent components) and electronic and electrical systems (especially miniaturized and high-frequency components).

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

[0033] First, this patent achieves effective control over the content of terminal amino groups in recycled polyamides by introducing chain extenders that can react with terminal carboxyl groups, while simultaneously increasing their molecular weight. This method not only inhibits chain segment degradation under acidic conditions but also synergistically improves the thermal stability and flame retardant properties of the material at the molecular structure level.

[0034] Secondly, based on specific terminal amino content and chain extender, by selecting specific ratios of aromatic polyamide and aliphatic polyamide to make the aryl repeating unit content 10-30wt%, the dimensional stability and chemical resistance can be improved.

[0035] Ultimately, the low concentration of end groups and the high molecular weight provide strong intermolecular forces, while the moderate aryl content contributes to excellent chain rigidity and thermal stability. The two work synergistically to achieve a comprehensive improvement in the dimensional stability, chemical resistance, thermal stability and flame retardant properties of recycled polyamide. Detailed Implementation

[0036] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0037] The raw materials for this invention are sourced as follows:

[0038] PA6-A: Terminal amino content is 120 mmol / kg, relative viscosity is 1.7, produced by Jinjiang Yonghong Renewable Resources Co., Ltd.

[0039] PA6-B: Terminal amino content is 140 mmol / kg, relative viscosity is 1.6, product manufactured by Kingfa Environmental Protection Technology Co., Ltd.

[0040] PA6-C: Terminal amino content is 150 mmol / kg, relative viscosity is 1.58, product manufactured by Kingfa Environmental Protection Technology Co., Ltd.

[0041] PA6-D: Terminal amino content is 170 mmol / kg, relative viscosity is 1.55, product manufactured by Kingfa Environmental Protection Technology Co., Ltd.

[0042] PA6-E: terminal amino content is 50 mmol / kg, relative viscosity is 2.5, and it contains 50 mmol / kg of Glyphs nitrogen.

[0043] PA6-F: Terminal amino content is 210 mmol / kg, relative viscosity is 1.3, produced by Kingfa Environmental Protection Technology Co., Ltd.

[0044] PA66-A: Terminal amino content 120mmol / kg, relative viscosity 2.7, Huafeng Group Co., Ltd.

[0045] PA66-B: Amino terminal content 150 mmol / kg, relative viscosity 1.9, Anhui Zhongyue New Materials Co., Ltd.

[0046] PA10T: Terminal amino content is 150 mmol / kg, relative viscosity is 1.5, Zhuhai Wantong Special Engineering Plastics Co., Ltd.

[0047] PA6T / 6I: Terminal amino content is 150 mmol / kg, relative viscosity is 1.5, Zhuhai Wantong Special Engineering Plastics Co., Ltd.

[0048] Chain extender A: 1,4-Butanediol diglycidyl ether, CAS: 2425-79-8, Aladdin;

[0049] Chain extender B: 1,3-phenylenebis(2-oxazoline), CAS: 34052-90-9, Aladdin;

[0050] Chain extender C: Pyromellitic dianhydride, CAS: 89-32-7, Hualun New Materials (Jiangsu) Co., Ltd.;

[0051] Chain extender D: Toluene diisocyanate, CAS: 26471-62-5, Macklin reagent;

[0052] Melamine cyanurate: MCA-F, purchased from Sichuan Fine Chemical Research and Design Institute;

[0053] Fiberglass: S1HM435TM-10-3, length 3mm, Taishan Fiberglass Co., Ltd.

[0054] Antioxidant: Bis(2,6-di-tert-butyl-4-tolyl) pentaerythritol phosphite, PEP-36, ADEKA;

[0055] Lubricant: Stearyl stearate, LOXIOL G32, Corning, Germany.

[0056] Preparation method of polyamide compositions in examples and comparative examples: The components were mixed evenly according to their respective contents, and then extruded and granulated using a twin-screw extruder to obtain the polyamide composition. The twin-screw extruder had a screw length-to-diameter ratio of 44:1, a barrel temperature of 280~310℃, and a screw speed of 250 rpm.

[0057] Test methods:

[0058] (1) Flame retardant performance: Vertical burning test, injection molded 125mm×13mm×0.8mm burning test strip, its flame retardant performance is tested according to UL 94 standard.

[0059] (2) Heat resistance aging test: According to GB / T 7141 "Plastics Aging Test Method", the tensile specimen (ISO 527-2-2012 standard 1A specimen) was placed in an aging chamber at 180℃ for 1000 hours. The tensile performance retention rate was tested as follows: tensile strength after aging / tensile strength before aging * 100% (tested according to ISO 527-2-2012 standard, tensile speed is 50mm / min).

[0060] (3) Chemical resistance: According to GB / T 7141 "Plastics Aging Test Method", the tensile specimen (ISO 527-2-2012 standard 1A specimen) was immersed in anhydrous ethanol solution for 48 hours. The tensile property retention rate was calculated as: tensile strength after test / tensile strength before test * 100% (tested according to ISO 527-2-2012 standard, tensile speed 50 mm / min).

[0061] (4) Dimensional stability: For injection molding of standard-sized square plates of 60mm×60mm×3mm, according to GB / T 15585-1995 standard for determination of shrinkage rate of thermoplastic injection molding, record the ratio of the difference between the injection molded sample and the mold cavity size to the mold cavity size, expressed as a percentage.

[0062] Table 1: Content (parts by weight) of each component in the polyamide compositions of Examples 1-7 and test results

[0063] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 PA6 grade B B B A C D B PA6 content 30.4 38 42.9 38 38 38 38 PA10T 25.6 32 36.1 32 32 32 PA6T / 6I 26 melamine cyanurate 10 15 8 15 15 15 15 Chain extender A 2 3 4 3 3 3 3 Fiberglass 10 0 20 0 0 0 0 antioxidants 0.5 0.5 0.5 0.5 0.5 0.5 0.5 lubricant 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Percentage of repeating units containing benzene rings (wt%) 20 20 20 20 20 20 20 Flame retardancy V-0 V-0 V-0 V-0 V-0 V-1 V-0 Heat aging retention rate % 88 91 96 89 92 90 91 Chemical resistance retention rate % 87 89 92 87 91 88 92 Shrinkage rate % 2.0 1.9 1.8 1.9 1.9 2.0 1.8

[0064] As can be seen from Examples 2 / 4 / 5 / 6, when the terminal amino concentration of the polyamide resin is preferably 120-160 mmol / kg, the flame retardancy reaches V-0 and the aging resistance and chemical resistance are better.

[0065] Table 2: Content (parts by weight) of each component in the polyamide compositions of Examples 8-13 and test results

[0066] Example 8 Example 9 Example 10 Example 11 Example 12 Example 13 PA6 grade B B B B PA6 content 54 46 30 22 PA66-A 38 PA66-B 38 PA10T 16 24 40 48 32 32 melamine cyanurate 15 15 15 15 15 15 Chain extender A 3 3 3 3 3 3 antioxidants 0.5 0.5 0.5 0.5 0.5 0.5 lubricant 0.5 0.5 0.5 0.5 0.5 0.5 Percentage of repeating units containing benzene rings (wt%) 10 15 25 30 20 20 Flame retardancy V-0 V-0 V-0 V-0 V-0 V-0 Heat aging retention rate % 88 90 88 86 93 92 Chemical resistance retention rate % 86 88 90 91 91 90 Shrinkage rate % 2.1 2.0 1.9 1.8 1.9 2.0

[0067] As can be seen from Examples 2 / 8-11, the preferred content of benzene ring repeating units is 15-25 wt%.

[0068] Table 3: Content (parts by weight) of each component in the comparative polyamide compositions and test results

[0069] Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 PA6 grade E F B B B B B PA6 content 38 38 70 0 62 8 38 PA10T 32 32 0 70 8 64 32 melamine cyanurate 15 15 15 15 15 15 15 Chain extender A 3 3 3 3 3 3 0 antioxidants 0.5 0.5 0.5 0.5 0.5 0.5 0.5 lubricant 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Percentage of repeating units containing benzene rings (wt%) 20 20 0 43.7 5 40 20 Flame retardancy V-0 V-2 V-0 V-0 V-0 V-0 V-1 Heat aging retention rate % 72 88 73 68 77 75 82 Chemical resistance retention rate % 81 85 76 87 78 83 77 Shrinkage rate % 2.5 2.3 3.1 1.9 2.8 2.3 2.2

[0070] As shown in Comparative Example 1, when the content of terminal amino groups in PA6 is too low, its heat aging resistance, chemical resistance, and shrinkage rate are poor.

[0071] As shown in Comparative Example 2, PA6 exhibits poor flame retardancy when the content of terminal amino groups is too high.

[0072] As can be seen from Comparative Examples 3-6, good resistance to heat aging and chemical resistance can only be achieved when the repeating units containing benzene rings in the polyamide resin matrix of the composition account for 10-30 wt%.

Claims

1. A polyamide composition, characterized in that, By weight, it includes the following components: 55-80 parts of polyamide resin; 8-15 parts of melamine cyanurate; Chain extender 2-4 parts; The polyamide resin is a blend of aromatic and aliphatic polyamide resins, and the repeating units containing benzene rings account for 10-30 wt% of the total weight percentage of the repeating units in the polyamide resin. The concentration of terminal amino groups in polyamide resin is 100-200 mmol / kg.

2. The polyamide composition according to claim 1, characterized in that, The polyamide resin is derived from virgin or recycled polyamide resin.

3. The polyamide composition according to claim 1, characterized in that, The polyamide resin is a blend of aromatic polyamide resin and aliphatic polyamide resin, and the repeating unit containing benzene ring accounts for 15-25 wt% of the total weight percentage of the repeating units of the polyamide resin.

4. The polyamide composition according to claim 1, characterized in that, The concentration of terminal amino groups in polyamide resin is 120-160 mmol / kg.

5. The polyamide composition according to claim 1, characterized in that, The chain extender is selected from at least one of the following: bis / polyepoxy functional group chain extenders, bis / polyoxazoline chain extenders, bis / polyanhydride chain extenders, and diisocyanate chain extenders.

6. The polyamide composition according to claim 5, characterized in that, The bis / polyepoxy functional group chain extender is selected from one or more of 1,4-butanediol diglycidyl ether, trimethylolpropane triglycidyl ether, glycerol polyglycidyl ether, styrene-glyceryl acrylate copolymer, or ethylene-methyl acrylate-glycidyl methacrylate terpolymer; the bis / polyoxazoline chain extender is selected from one or more of 1,3-phenylenebis(2-oxazoline), 1,2-phenylenebis(2-oxazoline), bis(2-oxazoline)alkane, poly(styrene-vinyl-2-oxazoline), or acrylate oxazoline copolymer; the bis / polyanhydride chain extender is selected from one or more of pyromellitic dianhydride, styrene-maleic anhydride copolymer, maleic anhydride grafted polyolefin, or ethylene propylene diene monomer (EPDM) grafted maleic anhydride; the diisocyanate chain extender is selected from one or more of toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, or dicyclohexylmethane diisocyanate.

7. The polyamide composition according to claim 1, characterized in that, The aromatic polyamide resin is selected from at least one of fully aromatic polyamides and semi-aromatic polyamides; the fully aromatic polyamide is selected from PPTA, and the semi-aromatic polyamide is selected from at least one of PA6T, PA10T, PA6I / 6T, PA10T / 1012, PA MXD10, and PA MXD6; the aliphatic polyamide resin is selected from at least one of AB-type aliphatic polyamides prepared by ring opening of ω-amino acids or lactams, and aliphatic polyamides formed by condensation of diacids and diamines, wherein the AB-type aliphatic polyamide is selected from at least one of PA6, PA11, and PA12; the aliphatic polyamide formed by condensation of diacids and diamines is selected from at least one of PA66, PA612, PA610, PA1010, PA1012, and PA1212; the relative viscosity range of the aromatic polyamide resin is 1.0-4.0, and the relative viscosity range of the aliphatic polyamide resin is 1.0-4.

0.

8. The polyamide composition according to claim 1, characterized in that, The product also includes 0-2 parts by weight of an auxiliary agent selected from at least one of antioxidants and lubricants; and 0-20 parts by weight of reinforcing fibers.

9. A method for preparing the polyamide composition according to any one of claims 1-8, characterized in that, The process includes the following steps: mixing the components evenly according to the formula, and granulating the mixture by extrusion through a twin-screw extruder to obtain a polyamide composition.

10. The use of the polyamide composition according to any one of claims 1-8, characterized in that, Used for manufacturing components for vehicle-mounted electric equipment, vehicle-mounted intelligent equipment, precision plastic components for electronic appliances, and high-frequency components for electronic appliances.