Flame-retardant polyamide composition and preparation method thereof

Abstract

The invention relates to a flame-retardant polyamide composition and a preparation method thereof. The present application first relates to a polyamide composition comprising: a) an aliphatic polyamide resin; b) a metal sulfide; c) a compatilizer; d) a coupling agent; e) an amorphous semi-aromatic polyamide resin; f) flat glass fibers; optionally g) a halogen-free flame retardant; optionally, h) an antioxidant; optionally i) a processing aid; the polyamide composition is prepared by the following method: 1) premixing components a) to d) to obtain a first premix; (2) putting the first premix into a double-screw extruder to obtain wear-resistant auxiliary master batch (second premix); 3) premixing the wear-resistant auxiliary agent master batch with a component e) and optional components g), h) and i) to obtain a third premix; 4) the third premix and the component f) are put into a double-screw extruder, the polyamide composition is obtained, the component f) enters from a side feeding port of the double-screw extruder, and other components enter from a main feeding port of the double-screw extruder.

Description

Technical Field

[0001] The term "polymer material field" in this application specifically relates to the field of polymer materials with high temperature resistance, friction resistance and low warping. Background Art

[0002] As an important lightweight thermoplastic, polyamide (nylon) is widely used in aerospace, automotive, instrumentation, home appliances, electronic communications, and new energy applications due to its excellent mechanical properties, wear resistance, and chemical corrosion resistance. In civil aviation, polyamide is primarily used in radomes, landing gear, inner and outer flap compartments, doors, and cabin interiors, enjoying a wide range of applications.

[0003] However, unmodified polyamide materials have drawbacks such as flammability, hygroscopicity, poor thermal stability, and high mold shrinkage, making them unsuitable for these industries. Therefore, polyamide modification is necessary. Furthermore, components such as gears, bearings, gaskets, bushings, and wiring harness jackets can suffer wear and tear from friction over long periods of use, posing a safety hazard.

[0004] Therefore, existing wear-resistant nylon usually needs to be reinforced with glass fiber to improve its wear resistance. However, the anisotropy of glass fiber leads to uneven shrinkage in each phase of the product, resulting in significant product warping.

[0005] On the other hand, when polyamide is modified, metal sulfides such as molybdenum disulfide are often added as wear-resistant additives. However, molybdenum disulfide has poor compatibility with the polymer matrix and is unevenly dispersed, which leads to a decrease in material performance.

[0006] There are many commercially available glass fiber-reinforced polyamide 66 products, and performance varies significantly between manufacturers. International manufacturers such as Dupont, BASF, Dow Chemical, and RTP generally offer different grades based on specific requirements, such as high heat resistance, aging resistance, and wear resistance. However, there are currently no polyamide 66 compounds that combine high-temperature resistance, friction resistance, and low warpage.

[0007] Therefore, there is still a need for the following polyamide composition, which can solve at least one of the problems in the prior art; advantageously, the composition can have the characteristics of high temperature resistance, friction resistance, low warpage, etc. without sacrificing mechanical properties. Summary of the Invention

[0008] The purpose of this application is to provide a polyamide composition that has the characteristics of high temperature resistance, friction resistance, low warping, etc. without sacrificing mechanical properties.

[0009] A first aspect of the present application relates to a polyamide composition comprising:

[0010] a) aliphatic polyamide resin;

[0011] b) metal sulfides;

[0012] c) compatibilizer;

[0013] d) coupling agent;

[0014] e) an amorphous semiaromatic polyamide resin;

[0015] f) flat glass fiber;

[0016] Optionally g) a halogen-free flame retardant;

[0017] Optionally h) an antioxidant;

[0018] Optionally i) processing aids;

[0019] The polyamide composition is prepared by the following method:

[0020] 1) premixing components a) to d) in a high-speed mixer to obtain a first premix;

[0021] 2) feeding the first premix into a twin-screw extruder to obtain a second premix as a wear-resistant additive masterbatch after melt extrusion, granulation, and drying;

[0022] 3) premixing the anti-wear additive masterbatch with component e), optionally g), optionally h), and optionally i) in a high-speed mixer to obtain a third premix,

[0023] 4) feeding the third premix and component f) the flat glass fiber into a twin-screw extruder, and subjecting the resulting mixture to a process comprising melt extrusion, granulation, and drying to obtain the polyamide composition, wherein component f) is fed from a side feed port of the twin-screw extruder, and the remaining components are fed from a main feed port of the twin-screw extruder.

[0024] The second aspect of the present application relates to a method for preparing the polyamide composition according to the first aspect, the method comprising:

[0025] 1) Premix the following components a) to d) in a high-speed mixer to obtain a first premix:

[0026] a) aliphatic polyamide resin;

[0027] b) metal sulfides;

[0028] c) compatibilizer;

[0029] d) coupling agent;

[0030] 2) feeding the first premix into a twin-screw extruder to obtain a second premix as a wear-resistant additive masterbatch after melt extrusion, granulation, and drying;

[0031] 3) Premixing the anti-wear additive masterbatch with the following components e), optionally g), optionally h), and optionally i) in a high-speed mixer to obtain a third premix:

[0032] e) an amorphous semiaromatic polyamide resin;

[0033] Optionally g) a halogen-free flame retardant;

[0034] Optionally h) an antioxidant;

[0035] Optionally i) processing aids;

[0036] 4) feeding the third premix and component f) the flat glass fiber into a twin-screw extruder, and subjecting the resulting mixture to a process comprising melt extrusion, granulation, and drying to obtain the polyamide composition, wherein component f) is fed from a side feed port of the twin-screw extruder, and the remaining components are fed from a main feed port of the twin-screw extruder.

[0037] The third aspect of the present application relates to the following polyamide composition, which comprises:

[0038] a) aliphatic polyamide resin;

[0039] b) metal sulfides;

[0040] c) compatibilizer;

[0041] d) coupling agent;

[0042] e) an amorphous semiaromatic polyamide resin;

[0043] f) flat glass fiber;

[0044] Optionally g) a halogen-free flame retardant;

[0045] Optionally h) an antioxidant;

[0046] Optionally i) processing aids;

[0047] The polyamide composition has the following characteristics:

[0048] -Tensile strength greater than 150MPa,

[0049] - flexural strength greater than 200MPa,

[0050] -Notched impact strength greater than 13kJ / m 2 ,

[0051] -Tensile strength retention rate greater than 70%;

[0052] - A coefficient of friction of less than 0.10; and

[0053] -Warp height is less than 0.5mm.

[0054] The applicant unexpectedly discovered that the use of the two-step preparation process described in the present application, together with specific components, enables the production of a polyamide composition having good mechanical properties, a low coefficient of friction and low warpage. DETAILED DESCRIPTION

[0055] As disclosed herein, "range" is defined in the form of a lower limit and an upper limit, and a given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of a particular range. The range defined in this way can be inclusive or exclusive of end values, and can be arbitrarily combined, i.e., any lower limit can be combined with any upper limit to form a range. For example, if a range of 60 to 120 and 80 to 110 is listed for a particular parameter, it is understood that a range of 60 to 110 and 80 to 120 is also contemplated. In addition, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4 and 5 are listed, the following ranges can all be contemplated: 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4 and 2 to 5. In this application, unless otherwise specified, the numerical range "a to b" represents an abbreviation of any real number combination between a and b, wherein a and b are both real numbers. For example, a numerical range of "0 to 5" indicates that all real numbers between "0 and 5" are listed herein, and "0 to 5" is merely an abbreviation for a combination of these values. Furthermore, when a parameter is expressed as an integer ≥ 2, this is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0056] In this application, unless otherwise specified, all embodiments and preferred embodiments mentioned herein can be combined with each other to form a new technical solution.

[0057] In this application, unless otherwise specified, all technical features and preferred features mentioned herein can be combined with each other to form a new technical solution.

[0058] In this application, unless otherwise specified, all steps mentioned herein may be performed sequentially or randomly, but are preferably performed sequentially. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), which means that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0059] In this application, unless otherwise specified, the terms "include" and "comprising" used herein may be open-ended or closed-ended. For example, "include" and "comprising" may mean that other components not listed may also be included or that only the listed components are included.

[0060] In the description of this article, it should be noted that, unless otherwise specified, “above” and “below” are inclusive of the number themselves, and “several” in “one or several” means two or more.

[0061] In the description herein, unless otherwise indicated, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B." More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0062] Herein, unless otherwise specified, percentages (%) or parts refer to percentages or parts by weight relative to the composition.

[0063] Herein, unless otherwise stated, the sum of the contents of the various components in the composition is 100%.

[0064] Herein, unless otherwise stated, the sum of the parts of each component in the composition may be 100 parts by weight.

[0065] In this context, unless otherwise stated, "a combination thereof" means a multi-component mixture of the elements mentioned, for example a mixture of two, three, four and up to the maximum possible multi-component mixture.

[0066] If not specifically stated, the terms "a" and "an" used in this specification mean "at least one".

[0067] Unless otherwise stated, all reactions are carried out at room temperature and pressure.

[0068] In the context of this application, the term "polyamide" can be used interchangeably with "polyamide resin", "PA", or "PA resin". For example, the term "aliphatic / semiaromatic / aromatic polyamide resin" can be used interchangeably with the terms "aliphatic / semiaromatic / aromatic polyamide", "aliphatic / semiaromatic / aromatic PA", and "aliphatic / semiaromatic / aromatic PA resin".

[0069] In the context of the present application, the expression "two-step process" is understood to mean a production process characterized by first preparing a masterbatch of the wear-resistant additive and then preparing the polyamide composition.

[0070] In the context of the present application, the expression "one-step process" is understood to mean a production process characterized by the direct production of the polyamide composition without prior production of a masterbatch of the wear-resistant additive.

[0071] The present application achieves beneficial technical effects in at least one of the following aspects:

[0072] - tensile strength, which can be tested, for example, according to ISO 527;

[0073] - Tensile strength retention, which can be tested, for example, by ISO 527 standard;

[0074] - flexural strength, which can be tested, for example, by ISO 178 standard;

[0075] - Flexural strength retention, which can be tested, for example, by ISO 178

[0076] - compressive strength, which can be tested, for example, by ASTM D695-10 standard;

[0077] - compression strength retention, which can be tested, for example, by standard ASTM D695-10;

[0078] - notched impact strength, which can be tested, for example, by ISO 179 standard;

[0079] - warpage height, which can be measured with a scale;

[0080] - softening point, which can be tested, for example, by standard GB 1633-79;

[0081] - Flame retardant properties, which can be tested, for example, by UL94 standard;

[0082] - Sliding friction coefficient, which can be tested, for example, by GB 5763 standard;

[0083] - aging performance, which can be tested, for example, by standard GB / T7141-2008;

[0084] - Mechanical properties of materials in case of reuse after recycling.

[0085] A first aspect of the present application relates to a polyamide composition, comprising:

[0086] a) aliphatic polyamide resin;

[0087] b) metal sulfides;

[0088] c) compatibilizer;

[0089] d) coupling agent;

[0090] e) an amorphous semiaromatic polyamide resin;

[0091] f) flat glass fiber;

[0092] Optionally g) a halogen-free flame retardant;

[0093] Optionally h) an antioxidant;

[0094] Optional i) processing aids

[0095] The polyamide composition is prepared by the following method:

[0096] 1) premixing components a) to d) in a high-speed mixer to obtain a first premix;

[0097] 2) feeding the first premix into a twin-screw extruder to obtain a second premix as a wear-resistant additive masterbatch after melt extrusion, granulation, and drying;

[0098] 3) premixing the anti-wear additive masterbatch with component e), optionally g), optionally h), and optionally i) in a high-speed mixer to obtain a third premix,

[0099] 4) feeding the third premix and component f) the flat glass fiber into a twin-screw extruder, and subjecting the resulting mixture to a process comprising melt extrusion, granulation, and drying to obtain the polyamide composition, wherein component f) is fed from a side feed port of the twin-screw extruder, and the remaining components are fed from a main feed port of the twin-screw extruder.

[0100] a) Aliphatic polyamide resin

[0101] The polyamide composition of the first aspect of the present application comprises an aliphatic polyamide resin. The nomenclature used to define polyamides is described in ISO standard 1874-1:2011 Plastics—Polyamide (PA) Moulding And Extrusion Materials—Part 1: Designation and is well known to those skilled in the art.

[0102] According to one embodiment, the aliphatic polyamide resin of the present application is obtained by the condensation of:

[0103] -C x aliphatic lactams;

[0104] -C y aliphatic amino acids; or

[0105] -C a Aliphatic diacids and C b Aliphatic diamine.

[0106] According to one embodiment, the C x Aliphatic lactams are selected from C4 to C 12 Aliphatic lactam, or C4 to C 10 Aliphatic lactam, or C4 to C8 aliphatic lactam.

[0107] According to one embodiment, the C x The aliphatic lactam is selected from the group consisting of: C4 aliphatic lactam, C5 aliphatic lactam, C6 aliphatic lactam, C7 aliphatic lactam, C8 aliphatic lactam, C9 aliphatic lactam, or C 10 Aliphatic lactam, or C 11 Aliphatic lactam, or C 12 Aliphatic lactams.

[0108] As C can be used in this application x As non-limiting examples of aliphatic lactams, there may be mentioned: butyrolactam, valerolactam, caprolactam, enantholactam, capryllactam, nonanolactam, decanolactam, undecanolactam, laurolactam.

[0109] According to one embodiment, the C y Aliphatic amino acids are selected from C4 to C 12 Aliphatic amino acids, or C4 to C 10 Aliphatic amino acids, or C4 to C8 aliphatic amino acids.

[0110] According to one embodiment, the C y The aliphatic amino acid is selected from the group consisting of: C4 aliphatic amino acid, or C5 aliphatic amino acid, or C6 aliphatic amino acid, or C7 aliphatic amino acid, or C8 aliphatic amino acid, or C9 aliphatic amino acid, or C 10 Aliphatic amino acids, or C 11 Aliphatic amino acids, or C 12 Aliphatic amino acids.

[0111] As C can be used in this application yAs non-limiting examples of aliphatic amino acids, there may be mentioned: 4-aminobutyric acid, 5-aminopentanoic acid, 4-aminopentanoic acid, 6-aminohexanoic acid, 5-aminohexanoic acid, 7-aminoheptanoic acid, 6-aminoheptanoic acid, 8-aminooctanoic acid, 7-aminooctanoic acid, 9-aminononanoic acid, 8-aminononanoic acid, 10-aminodecanoic acid, 9-aminodecanoic acid, 11-aminoundecanoic acid, 10-aminoundecanoic acid, 12-aminolauric acid, 11-aminolauric acid.

[0112] According to one embodiment, the C a Aliphatic diacids are selected from: C4 to C 12 Aliphatic diacids, or C4 to C 10 an aliphatic diacid, or a C4 to C8 aliphatic diacid.

[0113] According to one embodiment, the C a The aliphatic diacid is selected from the group consisting of: C4 aliphatic diacid, C5 aliphatic diacid, C6 aliphatic diacid, C7 aliphatic diacid, C8 aliphatic diacid, C9 aliphatic diacid, or C 10 Aliphatic diacid, or C 11 Aliphatic diacid, or C 12 Aliphatic diacid.

[0114] As C can be used in this application a As non-limiting examples of aliphatic diacids, there may be mentioned: succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid.

[0115] According to one embodiment, the C b Aliphatic diamines are selected from: C4 to C 12 Aliphatic diamine, or C4 to C 10 Aliphatic diamine, or C4 to C8 aliphatic diamine.

[0116] According to one embodiment, the C b The aliphatic diamine is selected from the group consisting of: C4 aliphatic diamine, or C5 aliphatic diamine, or C6 aliphatic diamine, or C7 aliphatic diamine, or C8 aliphatic diamine, or C9 aliphatic diamine, or C 10 Aliphatic diamine, or C 11 Aliphatic diamine, or C 12 Aliphatic diamine.

[0117] As C can be used in this application b As non-limiting examples of aliphatic diamines, there may be mentioned: 1,4-tetramethylenediamine, 1,5-pentamethylenediamine, 1,6-hexamethylenediamine, 1,7-heptamethylenediamine, 1,8-octamethylenediamine, 1,9-nonamethylenediamine, 1,10-decamethylenediamine, 1,11-undemethylenediamine, 1,12-dodecamethylenediamine.

[0118] In the polyamide composition described in the first aspect of the present application, the content of the aliphatic polyamide resin can be adjusted according to the desired properties of the final product.

[0119] According to one embodiment, in the polyamide composition described in the first aspect of the present application, the content of the aliphatic polyamide resin is 10 to 40 weight %, or 10 to 35 weight %, or 10 to 30 weight %, based on the total weight of the polyamide composition.

[0120] For example, in the polyamide composition described in the first aspect of the present application, the content of the aliphatic polyamide resin may be 10 weight%, or 11 weight%, or 12 weight%, or 13 weight%, or 14 weight%, or 15 weight%, or 16 weight%, or 17 weight%, or 18 weight%, or 19 weight%, or 20 weight%, or 21 weight%, or 22 weight%, or 23 weight%, or 24 weight%, or 25 weight%, or 26 weight%, or 27 weight%, or 28 weight%, or 29 weight%, or 30 weight%, or 31 weight%, or 32 weight%, or 33 weight%, or 34 weight%, or 35 weight%, or 36 weight%, or 37 weight%, or 38 weight%, or 39 weight%, or 40 weight%, based on the total weight of the polyamide composition.

[0121] b) Metal sulfides

[0122] The polyamide composition described in the first aspect of the present application contains metal sulfide.

[0123] According to one embodiment, the metal in the metal sulfide is selected from transition metals, Group IV metals, and Group V metals. In a preferred embodiment, the metal in the metal sulfide is selected from tin, bismuth, iron, cobalt, nickel, copper, zinc, molybdenum, and tungsten. In a more preferred embodiment, the metal sulfide is selected from one or more of molybdenum disulfide, tungsten disulfide, and bismuth sulfide.

[0124] In the polyamide composition described in the first aspect of the present application, the content of the metal sulfide can be adjusted according to the desired properties of the final product.

[0125] According to one embodiment, in the polyamide composition described herein, the content of the metal sulfide is 5 to 20 weight%, or 5 to 18 weight%, or 5 to 16 weight%, or 5 to 14 weight%, or 5 to 12 weight%, based on the total weight of the polyamide composition.

[0126] For example, in the polyamide composition described herein, the content of the metal sulfide may be 5 wt%, or 6 wt%, or 7 wt%, or 8 wt%, or 9 wt%, or 10 wt%, or 11 wt%, or 12 wt%, or 13 wt%, or 14 wt%, or 15 wt%, or 16 wt%, or 17 wt%, or 18 wt%, or 19 wt%, or 20 wt%, based on the total weight of the polyamide composition.

[0127] c) Compatibilizer

[0128] The polyamide composition described in the first aspect of the present application comprises a compatibilizer.

[0129] According to one embodiment, the compatibilizer is selected from a copolymer formed by a hydrophilic unit and a hydrophobic unit. Preferably, the compatibilizer is selected from a graft copolymer formed by a hydrophilic compound and a hydrophobic polymer.

[0130] According to one embodiment, in the copolymer formed by the hydrophilic unit and the hydrophobic unit, the hydrophilic unit is a unit derived from acrylic acid, acrylamide, vinyl alcohol, vinyl alcohol ester, vinyl sulfonic acid, p-vinylbenzoic acid, or maleic anhydride.

[0131] According to one embodiment, in the copolymer formed by the hydrophilic unit and the hydrophobic unit, the hydrophobic unit is a unit derived from α-olefin, diolefin, styrene, or acrylonitrile.

[0132] According to one embodiment, in the graft copolymer formed by the hydrophilic compound and the hydrophobic polymer, the hydrophilic compound is derived from one or more of acrylic acid, acrylamide, vinyl alcohol, vinyl alcohol ester, vinyl sulfonic acid, p-vinylbenzoic acid, or maleic anhydride.

[0133] According to one embodiment, in the graft copolymer formed by the hydrophilic polymer and the hydrophobic polymer, the hydrophobic polymer is formed by one or more of α-olefin, diene, styrene, and acrylonitrile.

[0134] As non-limiting examples of compatibilizers that can be used in the present application, one or more of PP-g-MAH, PE-g-MAH, EVA, and ABS-g-MAH can be mentioned.

[0135] In the polyamide composition described in the first aspect of the present application, the content of the compatibilizer can be adjusted according to the desired properties of the final product.

[0136] According to one embodiment, in the polyamide composition described in the first aspect of the present application, the content of the compatibilizer is 1 to 5 weight%, or 1 to 4.5 weight%, or 1 to 4 weight%, or 1 to 3.5 weight%, based on the total weight of the polyamide composition.

[0137] For example, in the polyamide composition described in the first aspect of the present application, the content of the compatibilizer may be 1.0 wt%, or 1.1 wt%, or 1.2 wt%, or 1.3 wt%, or 1.4 wt%, or 1.5 wt%, or 1.6 wt%, or 1.7 wt%, or 1.8 wt%, or 1.9 wt%, or 2.0 wt%, or 2.1 wt%, or 2.2 wt%, or 2.3 wt%, or 2.4 wt%, or 2.5 wt%, or 2.6 wt%, or 2.7 wt%, or 2.8 wt%, or 2.9 wt%. %, or 3.0 wt %, or 3.1 wt %, or 3.2 wt %, or 3.3 wt %, or 3.4 wt %, or 3.5 wt %, or 3.6 wt %, or 3.7 wt %, or 3.8 wt %, or 3.9 wt %, or 4.0 wt %, or 4.1 wt %, or 4.2 wt %, or 4.3 wt %, or 4.4 wt %, or 4.5 wt %, or 4.6 wt %, or 4.7 wt %, or 4.8 wt %, or 4.9 wt %, or 5.0 wt %, based on the total weight of the polyamide composition.

[0138] d) Coupling agent

[0139] The polyamide composition described in the first aspect of the present application comprises a coupling agent.

[0140] According to one embodiment, the coupling agent is selected from: a silane coupling agent, a titanate coupling agent, and an aluminate coupling agent.

[0141] Non-limiting examples of the silane coupling agent include KH550, KH560, KH570, KH590, KH602, KH172, KH902, and KRN8026. It should be understood that those skilled in the art may also use other silane coupling agents according to actual needs.

[0142] Non-limiting examples of the titanate coupling agent include: RZ-311W, NXH-401, HY-803, HTW-401, and TMC-311W. It should be understood that those skilled in the art may also use other titanate coupling agents according to actual needs.

[0143] As non-limiting examples of the aluminate coupling agent, there can be mentioned: JTW-18, isopropyl distearoyloxy aluminate, distearoyloxyphenoxy aluminate, DL411. However, it should be understood that those skilled in the art can also use other aluminate coupling agents according to actual needs.

[0144] In the polyamide composition described in the first aspect of the present application, the content of the coupling agent can be adjusted according to the desired properties of the final product.

[0145] According to one embodiment, in the polyamide composition described in the first aspect of the present application, the content of the coupling agent is 1 to 3 weight %, or 1 to 2.5 weight %, or 1 to 2 weight %, based on the total weight of the polyamide composition.

[0146] For example, in the polyamide composition described in the first aspect of the present application, the content of the coupling agent may be 1.0 weight%, or 1.1 weight%, or 1.2 weight%, or 1.3 weight%, or 1.4 weight%, or 1.5 weight%, or 1.6 weight%, or 1.7 weight%, or 1.8 weight%, or 1.9 weight%, or 2.0 weight%, or 2.1 weight%, or 2.2 weight%, or 2.3 weight%, or 2.4 weight%, or 2.5 weight%, or 2.6 weight%, or 2.7 weight%, or 2.8 weight%, or 2.9 weight%, or 3.0 weight%, based on the total weight of the polyamide composition.

[0147] e) Amorphous semi-aromatic polyamide resin

[0148] The polyamide composition described in the first aspect of the present application comprises an amorphous semi-aromatic polyamide resin.

[0149] According to one embodiment, the amorphous semiaromatic polyamide resin may be selected from PA6I, 11 / B10, 12 / B10, 11 / P10, 12 / P10, 11 / BI / BT, 12 / BI / BT, 11 / PI / BT, 12 / PI / BT, 11 / PI / PT, 12 / PI / PT, 11 / BI, 12 / BI, 11 / PI, and 12 / PI.

[0150] In the polyamide composition described in the first aspect of the present application, the content of the amorphous semi-aromatic polyamide resin can be adjusted according to the desired product properties.

[0151] According to one embodiment, in the polyamide composition described in the first aspect of the present application, the content of the amorphous semi-aromatic polyamide resin is 10 to 40 weight %, or 10 to 35 weight %, or 10 to 30 weight %, based on the total weight of the polyamide composition.

[0152] For example, in the polyamide composition described in the first aspect of the present application, the content of the amorphous semi-aromatic polyamide resin may be 10 weight%, or 11 weight%, or 12 weight%, or 13 weight%, or 14 weight%, or 15 weight%, or 16 weight%, or 17 weight%, or 18 weight%, or 19 weight%, or 20 weight%, or 21 weight%, or 22 weight%, or 23 weight%, or 24 weight%, or 25 weight%, or 26 weight%, or 27 weight%, or 28 weight%, or 29 weight%, or 30 weight%, or 31 weight%, or 32 weight%, or 33 weight%, or 34 weight%, or 35 weight%, or 36 weight%, or 37 weight%, or 38 weight%, or 39 weight%, or 40 weight%, based on the total weight of the polyamide composition.

[0153] f) Flat glass fiber

[0154] The polyamide composition described in the first aspect of the present application contains flat glass fibers.

[0155] In the context of this application, the terms "glass fiber" and "fiberglass" are used interchangeably.

[0156] In the context of this application, the term "flat glass fiber" means a glass fiber having the following characteristics: in a cross section perpendicular to the length direction of the glass fiber, there is a longer dimension L and a shorter dimension D.

[0157] According to one embodiment, in the polyamide composition described in the first aspect of the present application, the ratio L / D is 1.5 to 20, or 1.5 to 15, or 2 to 20.

[0158] For example, in the polyamide composition described in the first aspect of the present application, the ratio L to D L / D may be 1.5, or 1.6, or 1.7, or 1.8, or 1.9, or 2.0, or 2.2, or 2.4, or 2.6, or 2.8, or 3.0, or 3.2, or 3.4, or 3.6, or 3.8, or 4.0, or 4.2, or 4.4, or 4.6, or 4.8, or 5.0, or 5.2 , or 5.4, or 5.6, or 5.8, or 6.0, or 6.2, or 6.4, or 6.6, or 6.8, or 7.0, or 7.2, or 7.4, or 7.6, or 7.8, or 8.0, or 8.2, or 8.4, or 8.6, or 8.8, or 9.0, or 9.2, or 9.4, or 9.6, or 9.8, or 10.0, or 10.2, or 10.4, or 10.6, or 10.8, or 11.0, or 11.2, or 11.4, or 11.6, or 11.8, or 12.0, or 12.2, or 12.4, or 12.6, or 12.8, or 13.0, or 13.2, or 13.4, or 13.6, or 13.8, or 14.0, or 14.2, or 14.4, or 14.6, or 14.8, or 15.0, or 15.2, or 15 .4, or 15.6, or 15.8, or 16.0, or 16.2, or 16.4, or 16.6, or 16.8, or 17.0, or 17.2, or 17.4, or 17.6, or 17.8, or 18.0, or 18.2, or 18.4, or 18.6, or 18.8, or 19.0, or 19.2, or 19.4, or 19.6, or 19.8, or 20.0.

[0159] The L / D can be measured by methods known to those skilled in the art, such as calculating the L / D of the glass fiber by SEM images of the cross section. However, it should be understood that those skilled in the art can also use other methods to measure the L / D of the glass fiber.

[0160] In the polyamide composition described in the first aspect of the present application, the content of the flat glass fibers can be adjusted according to the desired properties of the final product.

[0161] According to one embodiment, in the polyamide composition described in the first aspect of the present application, the content of flat glass fibers is 15 to 40 wt%, or 15 to 40 wt%, or 20 to 35 wt%, based on the total weight of the polyamide composition.

[0162] For example, in the polyamide composition described in the first aspect of the present application, the content of flat glass fibers may be 15 weight%, or 16 weight%, or 17 weight%, or 18 weight%, or 19 weight%, or 20 weight%, or 21 weight%, or 22 weight%, or 23 weight%, or 24 weight%, or 25 weight%, or 26 weight%, or 27 weight%, or 28 weight%, or 29 weight%, or 30 weight%, or 31 weight%, or 32 weight%, or 33 weight%, or 34 weight%, or 35 weight%, or 36 weight%, or 37 weight%, or 38 weight%, or 39 weight%, or 40 weight%, based on the total weight of the polyamide composition.

[0163] g) Halogen-free flame retardants

[0164] According to a preferred embodiment, the polyamide composition described in the first aspect of the present application further comprises a halogen-free flame retardant.

[0165] According to one embodiment, the halogen-free flame retardant that can be used in the present application is selected from nitrogen-phosphorus flame retardants or phosphorus-based flame retardants.

[0166] As non-limiting examples of halogen-free flame retardants that can be used in the present application, there can be mentioned: triisopropylphenyl phosphate, melamine polyphosphate, triphenyl phosphate, ammonium polyphosphate, etc. However, it should be understood that those skilled in the art can also use other halogen-free flame retardants.

[0167] In the polyamide composition described in the first aspect of the present application, the content of the halogen-free flame retardant can be adjusted according to the desired properties of the final product.

[0168] According to one embodiment, in the polyamide composition described in the first aspect of the present application, the content of the halogen-free flame retardant is 15 to 30 weight %, or 15 to 25 weight %, based on the total weight of the polyamide composition.

[0169] For example, in the polyamide composition described in the first aspect of the present application, the content of the halogen-free flame retardant may be 15 weight%, or 16 weight%, or 17 weight%, or 18 weight%, or 19 weight%, or 20 weight%, or 21 weight%, or 22 weight%, or 23 weight%, or 24 weight%, or 25 weight%, or 26 weight%, or 27 weight%, or 28 weight%, or 29 weight%, or 30 weight%, based on the total weight of the polyamide composition.

[0170] h) Antioxidants

[0171] According to a preferred embodiment, the polyamide composition described in the first aspect of the present application may further comprise an antioxidant, wherein the antioxidant comprises a primary antioxidant and a secondary antioxidant.

[0172] According to one embodiment, the primary antioxidant is chosen from copper salts. As non-limiting examples of the primary antioxidant, mention may be made of those available under the references BTN, H318, H3386.

[0173] According to one embodiment, in the polyamide composition described in the first aspect of the present application, the content of the primary antioxidant is 0.01 to 1 weight %, or 0.01 to 0.8 weight %, or 0.01 to 0.6 weight %, or 0.01 to 0.4 weight %, based on the total weight of the polyamide composition.

[0174] For example, in the polyamide composition described in the first aspect of the present application, the content of the primary antioxidant may be 0.01 wt%, or 0.1 wt%, or 0.2 wt%, or 0.3 wt%, or 0.4 wt%, or 0.5 wt%, or 0.6 wt%, or 0.7 wt%, or 0.8 wt%, or 0.9 wt%, or 1.0 wt%, based on the total weight of the polyamide composition.

[0175] According to one embodiment, the secondary antioxidant is selected from hindered phenols and phosphites.

[0176] According to one embodiment, in the polyamide composition described in the first aspect of the present application, the content of the secondary antioxidant is 0.01 to 1 weight %, or 0.01 to 0.8 weight %, or 0.01 to 0.6 weight %, or 0.01 to 0.4 weight %, based on the total weight of the polyamide composition.

[0177] For example, in the polyamide composition described in the first aspect of the present application, the content of the secondary antioxidant may be 0.01 wt%, or 0.1 wt%, or 0.2 wt%, or 0.3 wt%, or 0.4 wt%, or 0.5 wt%, or 0.6 wt%, or 0.7 wt%, or 0.8 wt%, or 0.9 wt%, or 1.0 wt%, based on the total weight of the polyamide composition.

[0178] i) Processing aids

[0179] According to a preferred embodiment, the polyamide composition described in the first aspect of the present application may further comprise a processing aid.

[0180] In the context of the present application, the term "processing aid" means a component which, in addition to the above-mentioned components a) to h), can impart beneficial properties to the final product or make processing easier.

[0181] As non-limiting examples of processing aids that can be used in the present application, OP wax, rice bran wax, CAV102, 816A, pentaerythritol stearate, ethylene bisoleamide, aluminum stearate, calcium montanate, sodium montanate, or combinations thereof can be mentioned. However, those skilled in the art will appreciate that the processing aids that can be used in the present application are by no means limited thereto.

[0182] In the polyamide composition described in the first aspect of the present application, the content of the processing aid can be adjusted according to the desired properties of the final product.

[0183] According to one embodiment, in the polyamide composition described in the first aspect of the present application, the content of the processing aid is 0.1 to 2 weight%, or 0.1 to 1.8 weight%, or 0.1 to 1.6 weight%, or 0.1 to 1.4 weight%, or 0.1 to 1.2 weight%, or 0.1 to 1.0 weight%, based on the total weight of the polymer composition.

[0184] For example, in the polyamide composition described in the first aspect of the present application, the content of the processing aid may be: 0.1 weight%, or 0.2 weight%, or 0.3 weight%, or 0.4 weight%, or 0.5 weight%, or 0.6 weight%, or 0.7 weight%, or 0.8 weight%, or 0.9 weight%, or 1.0 weight%, or 1.1 weight%, or 1.2 weight%, or 1.3 weight%, or 1.4 weight%, or 1.5 weight%, or 1.6 weight%, or 1.7 weight%, or 1.8 weight%, or 1.9 weight%, or 2.0 weight%, based on the total weight of the polymer composition.

[0185] The polyamide composition described in the first aspect of the present application is prepared by a method comprising the following steps:

[0186] 1) premixing components a) to d) in a high-speed mixer to obtain a first premix;

[0187] 2) feeding the first premix into a twin-screw extruder to obtain a second premix as a wear-resistant additive masterbatch after melt extrusion, granulation, and drying;

[0188] 3) premixing the wear-resistant additive masterbatch with component e), optionally g), optionally h), and optionally i) in a high-speed mixer to obtain a third premix;

[0189] 4) feeding the third premix and component f) into a twin-screw extruder, and subjecting the mixture to a process comprising melt extrusion, granulation, and drying to obtain the polyamide composition, wherein component f) is fed from a side feed port of the twin-screw extruder, and the remaining components are fed from a main feed port of the twin-screw extruder.

[0190] It should be understood that the description of the above sub-steps is exemplary rather than limiting, and those skilled in the art may also use other processes to perform the above sub-steps.

[0191] For example, for step 1) and step 3), those skilled in the art know that they can also be carried out by other similar methods. For example, sub-step 1-1 can also be carried out in a planetary mixer, an internal mixer, or an open mixer.

[0192] In step 2) and step 4), the two screws of the twin-screw extruder can be arranged to rotate in the same direction or in counter-direction. Advantageously, the two screws of the twin-screw extruder can be arranged to rotate in counter-direction.

[0193] The second aspect of the present application relates to a method for preparing the polyamide composition described in the first aspect of the present application, the method comprising:

[0194] 1) Premix the following components a) to d) in a high-speed mixer to obtain a first premix:

[0195] a) aliphatic polyamide resin;

[0196] b) metal sulfides;

[0197] c) compatibilizer;

[0198] d) coupling agent;

[0199] 2) feeding the first premix into a twin-screw extruder to obtain a second premix as a wear-resistant additive masterbatch after melt extrusion, granulation, and drying;

[0200] 3) Premixing the anti-wear additive masterbatch with the following components e), optionally g), optionally h), and optionally i) in a high-speed mixer to obtain a third premix:

[0201] e) an amorphous semiaromatic polyamide resin;

[0202] Optionally g) a halogen-free flame retardant;

[0203] Optionally h) an antioxidant;

[0204] Optionally i) processing aids;

[0205] 4) feeding the third premix and component f) the flat glass fiber into a twin-screw extruder, and subjecting the resulting mixture to a process comprising melt extrusion, granulation, and drying to obtain the polyamide composition, wherein component f) is fed from a side feed port of the twin-screw extruder, and the remaining components are fed from a main feed port of the twin-screw extruder.

[0206] Components a) to g) and each step described in the second aspect of the present application are the same as those described in the first aspect of the present application.

[0207] The third aspect of the present application relates to the following polyamide composition, which comprises:

[0208] a) aliphatic polyamide resin;

[0209] b) metal sulfides;

[0210] c) compatibilizer;

[0211] d) coupling agent;

[0212] e) an amorphous semiaromatic polyamide resin;

[0213] f) flat glass fiber;

[0214] Optionally g) a halogen-free flame retardant;

[0215] Optionally h) an antioxidant;

[0216] Optionally i) processing aids;

[0217] The polyamide composition has the following characteristics:

[0218] -Tensile strength greater than 150MPa,

[0219] - flexural strength greater than 200MPa,

[0220] -Notched impact strength greater than 13kJ / m2,

[0221] -Tensile strength retention rate greater than 70%;

[0222] - A coefficient of friction of less than 0.10; and

[0223] -Warp height is less than 0.5mm.

[0224] Example

[0225] The present application is further described below with reference to the following examples. However, the following examples are merely illustrative and in no way limit the present application. The examples and comparative examples of the present application use the materials described in Table 1 below, but are not limited to the materials described in Table 1.

[0226] Table 1 Materials used in Examples and Comparative Examples

[0227]

[0228]

[0229] *The L / D of the flat glass fiber used in the examples is 4 / 1, and the L / D is as described above.

[0230] The performance test standards and / or methods in the embodiments and comparative examples are as follows:

[0231] (1) Tensile strength: according to ISO 527 method, specimen size 170*10*4mm, test speed 5mm / min;

[0232] (2) Notched impact strength: according to ISO 179 / 1eA method, specimen size 80*10*4mm;

[0233] (3) Flexural strength: according to ISO 178 method, specimen size 80*10*4mm, test speed 2mm / min;

[0234] (4) Warpage performance: Using a 150*100*3 mm sample bar, place the sample plate on a table, squeeze three corners of the plate to raise the fourth corner. Then measure the warpage height between the table surface and the sample surface.

[0235] (5) Flame retardant performance: According to UL94 method, the sample size is 125*10*1.6mm;

[0236] (6) Friction coefficient: according to GB 5763 method, sample size 25*25*2mm;

[0237] Example 1:

[0238] Example 1 is carried out by the following steps:

[0239] 1) Weigh each component according to the mass percentage in Table 2.

[0240] 2) Dry the PA6I resin and PA66 resin in a vacuum circulation oven at 120° C. for 6 h, controlling the moisture content of the resin to <0.3%.

[0241] 3) The dried PA66 resin, metal sulfide, compatibilizer, and coupling agent were uniformly mixed in a high-speed mixer according to the proportions shown in Table 2 to obtain a first premix. The first premix was added through the main feed port of a twin-screw extruder and subjected to melt extrusion, granulation, and drying in this order to obtain a second premix serving as a masterbatch for the wear-resistant additive.

[0242] 4) The wear-resistant additive masterbatch obtained in step 3) is uniformly mixed with the polyamide PA6I resin, halogen-free flame retardant, primary antioxidant, secondary antioxidant, and processing aid, which have been weighed according to the amounts of the components listed in Table 2, in a high-speed mixer to produce a third premix. The third premix is added through the main feed port of a twin-screw extruder, and the flat glass fiber is added through the side feed port. The components are melt-extruded, granulated, and dried to produce a polyamide composition.

[0243] Example 2 Example 1 was repeated except that 5 wt % of molybdenum disulfide was replaced by 5 wt % of bismuth sulfide.

[0244] Example 3 Example 1 was repeated, except that the content of molybdenum disulfide was increased to 10 wt %, based on the total weight of the polyamide composition; and the content of PA6I was correspondingly reduced to 15 wt %, based on the total weight of the polyamide composition.

[0245] Comparative Example 1 Example 1 was repeated, except that no PA6I was added and the content of PA66 was increased to 39.5% by weight, relative to the total weight of the polyamide composition.

[0246] Comparative Example 2 Example 1 was repeated except that no metal disulfide was added and the PA6I content was increased to 25 wt%.

[0247] Comparative Example 3 Example 1 was repeated except that no compatibilizer was added and the PA6I content was increased to 23 wt %.

[0248] Comparative Example 4 Example 1 was repeated except that no coupling agent was added and the content of PA6I was increased to 21.5 wt %.

[0249] Comparative Example 5 : The polyamide composition is prepared by a one-step method, and the specific preparation process is as follows:

[0250] 1) Weigh each component according to the mass percentage in Table 2.

[0251] 2) Dry the PA6I resin and PA66 resin in a vacuum circulation oven at 120° C. for 6 h, controlling the moisture content of the resin to <0.3%.

[0252] 3) All components except flat glass fiber are mixed uniformly in a high-speed mixer.

[0253] 4) The premix obtained in step 3) is added from the main feed port of a twin-screw extruder, and the flat glass fiber is added from the side feed port. The components are subjected to melt extrusion, granulation, and drying to obtain a polyamide composition.

[0254] Comparative Example 6 Example 1 was repeated, except that no halogen-free flame retardant was added and the content of PA6I was increased to 40 wt %, relative to the total weight of the polyamide composition.

[0255] Comparative Example 7Example 1 was repeated, except that no primary antioxidant was added and the content of PA66 was increased to 19.8 wt %, relative to the total weight of the polyamide composition.

[0256] Comparative Example 8 Example 1 was repeated, except that: no primary antioxidant was added, the content of PA66 was increased to 19.8 wt %, relative to the total weight of the polyamide composition; and round glass fiber was used instead of flat glass fiber.

[0257] The performance test results of the polyamide compositions obtained in various examples and comparative examples are shown in Table 2.

[0258] Table 2

[0259]

[0260]

[0261] * Conventional round glass fibers were used in Comparative Example 8, while flat glass fibers were used in the remaining comparative examples and all the examples.

[0262] It can be seen from the results shown in the examples and comparative examples that the present application obtains a polyamide composition having good mechanical properties, low friction coefficient and low warpage performance by using a two-step preparation process and specific components.

[0263] Comparison of Example 1 and Comparative Example 5 shows that the preparation process of the polyamide composition of the present application has a significant effect on the performance of the final polyamide composition. The difference between Example 1 and Comparative Example 5 is that Example 1 adopts the two-step method described in the present application to prepare the polyamide composition, while Comparative Example 5 adopts the one-step method to prepare the polyamide composition. The results in Table 2 are limited. When all the components are the same, the use of the two-step method can significantly improve the tensile strength (from 143 MPa to 181 MPa) and notched impact strength (from 9.8 kJ / m2 to 1.6 kJ / m3) of the polyamide composition relative to the use of the one-step method without sacrificing the high flexural strength, high tensile strength retention rate, low friction coefficient and low warpage height of the polyamide composition. 2 Increased to 16.4kJ / m 2 ).

[0264] Comparison between Example 1 and Examples 3 and 4 shows that the combined use of a compatibilizer and a coupling agent brings about a significant improvement in the tensile strength and notched impact strength of the polyamide composition, without sacrificing other properties of the polyamide composition (including flexural strength, tensile strength retention, flame retardancy, friction coefficient, and low warpage).

[0265] Comparison of Example 1 and Comparative Example 1 shows that the simultaneous use of the aliphatic polyamide resin and the amorphous semi-aromatic polyamide resin significantly reduces the warpage height of the polyamide composition (from 2.1 mm to 0.2 mm).

[0266] In addition, the cross-sectional shape of the glass fiber also has a significant impact on the performance of the polyamide composition. The results of Comparative Example 8 show that the use of round glass fibers significantly increases the warpage of the polyamide composition.

[0267] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A polyamide composition comprising: a) aliphatic polyamide resin; b) metal sulfides; c) compatibilizer; d) coupling agent; e) an amorphous semiaromatic polyamide resin; f) flat glass fiber; Optionally g) a halogen-free flame retardant; Optionally h) an antioxidant; Optionally i) processing aids; The polyamide composition is prepared by the following method: 1) premixing components a) to d) in a high-speed mixer to obtain a first premix; 2) feeding the first premix into a twin-screw extruder to obtain a second premix as a wear-resistant additive masterbatch after melt extrusion, granulation, and drying; 3) premixing the anti-wear additive masterbatch with component e), optionally g), optionally h), and optionally i) in a high-speed mixer to obtain a third premix, 4) feeding the third premix and component f) the flat glass fiber into a twin-screw extruder, and subjecting the resulting mixture to a process comprising melt extrusion, granulation, and drying to obtain the polyamide composition, wherein component f) is fed from a side feed port of the twin-screw extruder, and the remaining components are fed from a main feed port of the twin-screw extruder.

2. The polyamide composition according to claim 1, wherein (1) The aliphatic polyamide resin is obtained by the condensation of: -C x aliphatic lactams; -C y aliphatic amino acids; or -C a Aliphatic diacids and C b Aliphatic diamine. Preferably: The C x Aliphatic lactams are selected from C4 to C 12 Aliphatic lactam, or C4 to C 10 an aliphatic lactam, or a C4 to C8 aliphatic lactam; and / or The C y Aliphatic amino acids are selected from C4 to C 12 Aliphatic amino acids, or C4 to C 10 aliphatic amino acids, or C4 to C8 aliphatic amino acids; and / or The C a Aliphatic diacids selected from C4 to C 12 Aliphatic diacids, or C4 to C 10 an aliphatic diacid, or a C4 to C8 aliphatic diacid; and / or The C b Aliphatic diamines are selected from C4 to C 12 Aliphatic diamine, or C4 to C 10 Aliphatic diamine, or C4 to C8 aliphatic diamine; and / or (2) The content of the aliphatic polyamide resin is 10 to 40 wt%, or 10 to 35 wt%, or 10 to 30 wt%, based on the total weight of the polyamide composition.

3. The polyamide composition of claim 1, wherein the metal sulfide has one or more of the following characteristics: (1) The metal in the metal sulfide is selected from transition metals, Group IV metals, and Group V metals; and / or (2) The metal in the metal sulfide is selected from tin, bismuth, iron, cobalt, nickel, copper, zinc, molybdenum, and tungsten; and / or (3) The content of the metal sulfide is 5 to 20 weight percent, or 5 to 18 weight percent, or 5 to 16 weight percent, or 5 to 14 weight percent, or 5 to 12 weight percent, based on the total weight of the polyamide composition.

4. The polyamide composition according to claim 1, wherein the compatibilizer is selected from a copolymer formed by a hydrophilic unit and a hydrophobic unit, preferably selected from a graft copolymer formed by a hydrophilic compound and a hydrophobic polymer; Preferably, the compatibilizer has one or more of the following characteristics: (1) The hydrophilic unit is a unit derived from acrylic acid, acrylamide, vinyl alcohol, vinyl alcohol ester, vinyl sulfonic acid, p-vinylbenzoic acid, or maleic anhydride; and / or (2) The hydrophobic unit is a unit derived from α-olefin, diolefin, styrene, or acrylonitrile; and / or (3) the hydrophilic compound is derived from one or more of acrylic acid, acrylamide, vinyl alcohol, vinyl alcohol ester, vinyl sulfonic acid, p-vinyl benzoic acid, or maleic anhydride; and / or (4) The hydrophobic polymer is formed from one or more of α-olefins, diolefins, styrene, and acrylonitrile; and / or (5) The compatibilizer is selected from one or more of PP-g-MAH, PE-g-MAH, EVA, and ABS-g-MAH; and / or (6) The content of the compatibilizer is 1 to 5 weight %, or 1 to 4.5 weight %, or 1 to 4 weight %, or 1 to 3.5 weight %, based on the total weight of the polyamide composition.

5. The polyamide composition of claim 1 , wherein the coupling agent has one or more of the following characteristics: (1) The coupling agent is selected from one or more of a silane coupling agent, a titanate coupling agent, and an aluminate coupling agent; and / or (2) The content of the coupling agent is 1 to 3 wt%, or 1 to 2.5 wt%, or 1 to 2 wt%, based on the total weight of the polyamide composition.

6. The polyamide composition of claim 1 , wherein the amorphous semi-aromatic polyamide resin has one or more of the following characteristics: (1) The amorphous semi-aromatic polyamide resin is selected from the group consisting of PA6I, 11 / B10, 12 / B10, 11 / P10, 12 / P10, 11 / BI / BT, 12 / BI / BT, 11 / PI / BT, 12 / PI / BT, 11 / PI / PT, 12 / PI / PT, 11 / BI, 12 / BI, 11 / PI and 12 / PI; and / or (2) The content of the amorphous semi-aromatic polyamide resin is 10 to 40 wt%, or 10 to 35 wt%, or 10 to 30 wt%, or 10 to 25 wt%, based on the total weight of the polyamide composition.

7. The polyamide composition of claim 1 , wherein the flat glass fibers have one or more of the following characteristics: (1) The flat glass fiber has a ratio L / D of the longer dimension L to the shorter dimension D in a cross section of the flat glass fiber perpendicular to the length direction of the flat glass fiber of 1.5 to 20, or 1.5 to 15, or 2 to 20; and / or (2) The content of the flat glass fiber is 15 to 40 wt%, or 15 to 40 wt%, or 20 to 35 wt%, based on the total weight of the polyamide composition.

8. The polyamide composition of claim 1 , wherein the polyamide composition further comprises one or more of the following components g), h), and i): g) Halogen-free flame retardant; Preferably, the halogen-free flame retardant has one or more of the following characteristics: (1) the content of the halogen-free flame retardant is 15 to 30 wt %, or 15 to 25 wt %, based on the total weight of the polyamide composition; and / or (2) The halogen-free flame retardant is selected from nitrogen-phosphorus flame retardants or phosphorus-based flame retardants; h) antioxidants; Preferably, the antioxidant comprises a primary antioxidant and a secondary antioxidant; Preferably, the antioxidant has one or more of the following characteristics: (1) The primary antioxidant is selected from copper salts; and / or (2) The primary antioxidant is selected from BTN, H318, and H3386; and / or (3) the content of the primary antioxidant is 0.01 to 1 weight %, or 0.01 to 0.8 weight %, or 0.01 to 0.6 weight %, or 0.01 to 0.4 weight %, based on the total weight of the polyamide composition; and / or (4) The secondary antioxidant is selected from the group consisting of hindered phenols and phosphites; and / or (5) the content of the secondary antioxidant is 0.01 to 1 weight %, or 0.01 to 0.8 weight %, or 0.01 to 0.6 weight %, or 0.01 to 0.4 weight %, based on the total weight of the polyamide composition; i) Processing aids Preferably, the processing aid has one or more of the following characteristics: (1) the processing aid is present in an amount of 0.1 to 2 wt %, or 0.1 to 1.8 wt %, or 0.1 to 1.6 wt %, or 0.1 to 1.4 wt %, or 0.1 to 1.2 wt %, or 0.1 to 1.0 wt %, based on the total weight of the polymer composition; and / or (2) The processing aid is selected from OP wax, rice bran wax, CAV102, 816A, pentaerythritol stearate, ethylene bisoleamide, aluminum stearate, calcium montanate, sodium montanate, or a combination thereof.

9. A method for preparing a polyamide composition according to any one of claims 1 to 8, comprising: 1) Premix the following components a) to d) in a high-speed mixer to obtain a first premix: a) aliphatic polyamide resin; b) metal sulfides; c) compatibilizer; d) coupling agent; 2) feeding the first premix into a twin-screw extruder to obtain a second premix as a wear-resistant additive masterbatch after melt extrusion, granulation, and drying; 3) Premixing the anti-wear additive masterbatch with the following components e), optionally g), optionally h), and optionally i) in a high-speed mixer to obtain a third premix: e) an amorphous semiaromatic polyamide resin; Optionally g) a halogen-free flame retardant; Optionally h) an antioxidant; Optionally i) processing aids; 4) feeding the third premix and component f) the flat glass fiber into a twin-screw extruder, and subjecting the resulting mixture to a process comprising melt extrusion, granulation, and drying to obtain the polyamide composition, wherein component f) is fed from a side feed port of the twin-screw extruder, and the remaining components are fed from a main feed port of the twin-screw extruder.

10. A polyamide composition comprising: a) aliphatic polyamide resin; b) metal sulfides; c) compatibilizer; d) coupling agent; e) an amorphous semiaromatic polyamide resin; f) flat glass fiber; Optionally g) a halogen-free flame retardant; Optionally h) an antioxidant; Optionally i) processing aids; The polyamide composition has the following characteristics: -Tensile strength greater than 150MPa, - flexural strength greater than 200MPa, -Notched impact strength greater than 13kJ / m 2 , - Tensile strength retention greater than 70%; - Friction coefficient less than 0.10; and -Warp height is less than 0.5mm.

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