A low water absorption low warpage flame retardant polyamide composition and a method for preparing the same

Abstract

The application discloses a low-water-absorption low-warp flame-retardant polyamide composition which is prepared from the following components in parts by weight: polyamide resin 50-75 parts, polyphenyl ether 25-50 parts, glass fiber 10-60 parts, composite compatilizer 3.6-12.6 parts, flame retardant 15-40 parts, synergist 2-15 parts, nano oxide 0.5-2 parts, antioxidant 0.2-0.5 parts, lubricant 0.5-1.5 parts. The application reduces the linear expansion coefficient and warping degree of nylon 6 composite material by compounding polyphenyl ether and glass fiber, improves the compatibility between polyamide / polyphenyl ether and glass fiber, and the processing performance and mechanical properties of the polyamide composition by compounding polyphenyl ether grafted maleic anhydride, hydrogenated styrene-isoprene copolymer grafted maleic anhydride, silane coupling agent and polyhydric alcohol.

Description

Technical Field

[0001] This invention relates to the field of polymer materials, and in particular to a low water absorption, low warpage, flame-retardant polyamide composition and its preparation method. Background Technology

[0002] Polyamides (PA), particularly PA6 and PA66, are characterized by high strength and excellent resistance to general chemicals, making them widely used as general-purpose engineering plastics in home appliances, automobiles, and electronic and electrical engineering fields. PA6 and PA66 have high operating temperatures and possess excellent properties such as toughness, stiffness, and self-lubrication. When reinforced with glass fiber, they exhibit even higher mechanical strength, toughness, and better dimensional stability, but they suffer from drawbacks such as high water absorption and susceptibility to warping. Polyphenylene oxide (PPO), on the other hand, is a non-crystalline resin with good mechanical properties, low water absorption, and heat resistance, but it is difficult to process and has poor chemical resistance. Preparing flame-retardant reinforced polyamide / polyphenylene oxide compositions from polyamides and polyphenylene oxide can overcome the shortcomings of both, resulting in compositions with high mechanical properties, low water absorption, low warping, and good flame retardancy. However, due to the significant difference in molecular polarity between polyamide and polyphenylene ether, they are thermodynamically incompatible, resulting in weak interfacial forces between the two phases. Consequently, the macroscopic properties of the material, such as strength and toughness, are insufficient. Therefore, the key to preparing flame-retardant reinforced polyamide / polyphenylene ether compositions lies in compatibility technology. Summary of the Invention

[0003] In view of this, the present invention provides a flame-retardant polyamide composition with excellent performance and processing properties, as well as low water absorption and low warpage, and a method for preparing the same, which can be applied in the automotive, aerospace, electronics and electrical, and home appliance industries.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] This invention discloses a low-water-absorption, low-warpage flame-retardant polyamide composition, which is prepared from the following components in parts by weight:

[0006]

[0007]

[0008] As a further aspect of the present invention: the composite compatibilizer is prepared by compounding polyphenylene ether grafted maleic anhydride, SEPS-g-MAH, polyol and silane coupling agent in a mass ratio of (1.5-5):(1-3):(1-4):(0.1-0.6).

[0009] As a further aspect of the present invention: the maleic anhydride grafting rate of the polyphenylene ether grafted with maleic anhydride is 0.8-1.6%; the polyol is at least one of pentaerythritol, dipentaerythritol, trimethylolethane, and tripentaerythritol.

[0010] As a further aspect of the present invention: the polyamide resin is selected from at least one of PA66 and PA6, and has a relative viscosity of 2.0 to 2.8.

[0011] As a further aspect of the present invention, the intrinsic viscosity of the polyphenylene ether resin is 0.33 to 0.45 dL / g.

[0012] As a further aspect of the present invention: the nano oxide is at least one of nano zinc oxide, nano magnesium oxide, nano aluminum oxide, nano zirconium oxide, and nano iron oxide, with a particle size of 30-85 nm.

[0013] As a further aspect of the present invention: the glass fiber is E-type glass fiber with a fiber diameter of 7-14 μm.

[0014] As a further aspect of the present invention: the flame retardant is at least one of brominated polystyrene, polybrominated styrene, decabromodiphenyl ethane, and brominated epoxy resin; the synergistic flame retardant is at least one of antimony trioxide, antimony pentoxide, sodium antimonate, zinc borate, and silicon stannate.

[0015] As a further aspect of the present invention: the antioxidant is at least one selected from β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate n-octadecyl alcohol ester, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine, bis(2,4-di-tert-butylphenyl)pentaerythritol, zinc pentaerythritol, 2,6-di-tert-butyl-4-4-cresol, and tris(2,4-di-tert-butylphenyl)phosphite; the lubricant is at least one selected from OP wax, rosin ester wax, ethylene bis-stearamide, calcium stearate, zinc stearate, and aluminum stearate.

[0016] Another aspect of the present invention discloses a method for preparing a low-absorption, low-warpage flame-retardant polyamide composition as described in any of the preceding claims, comprising the following steps:

[0017] (1) The dried polyamide resin, polyphenylene ether, polyphenylene ether grafted maleic anhydride, hydrogenated styrene-isoprene copolymer grafted maleic anhydride (SEPS-g-MAH), flame retardant, synergist, polyol, nano oxide, silane coupling agent, antioxidant, and lubricant are mixed at high speed to obtain a mixture.

[0018] (2) The mixture is added to the main feed port of a parallel twin-screw extruder, and glass fiber is added to the side feed port of the parallel twin-screw extruder. After melt extrusion and granulation, low water absorption, low warpage, and flame retardant polyamide composition granules are obtained.

[0019] The drying temperature in step (1) is 90-120°C, and the drying time is 3-6 hours;

[0020] The process parameters of the parallel twin-screw extruder mentioned in step (2) include: zone 1 temperature of 230-280℃, zone 2 temperature of 235-285℃, zone 3 temperature of 235-285℃, zone 4 temperature of 240-290℃, zone 5 temperature of 240-290℃, zone 6 temperature of 235-275℃, zone 7 temperature of 235-275℃, zone 8 temperature of 235-275℃, die temperature of 235-275℃, and screw speed of 300-500 rpm.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] 1. To address the drawbacks of polyamide compositions, such as a high coefficient of linear expansion and poor dimensional stability, this invention reduces the coefficient of linear expansion and warpage of nylon 6 composites by combining polyphenylene ether (PPE) and glass fiber. The compatibility between polyphenylene ether / PPE and glass fiber, as well as the processing and mechanical properties of the polyamide composition, are improved by compounding PPE grafted with maleic anhydride, hydrogenated styrene-isoprene copolymer grafted with maleic anhydride, silane coupling agents, and polyols. This invention enhances the interfacial bonding and compatibility between polyamide and glass fiber by adding the aforementioned additives, while simultaneously improving the mechanical and processing properties of the polyamide composition, reducing its coefficient of linear expansion, and exhibiting lower water absorption and warpage. This results in a polyamide composition with excellent overall performance.

[0023] 2. The present invention uses polyphenylene ether grafted with maleic anhydride, hydrogenated styrene-isoprene copolymer grafted with maleic anhydride, polyol and silane coupling agent to generate hydrogen bonding reaction with the polar groups of polyamide, increase the compatibility between components, reduce the water absorption of polyamide, and thus prepare a polyamide composition with low water absorption.

[0024] 3. The nano-oxide used in this invention has at least one dimension at the nanoscale, which has a unique small size effect, large surface energy, enhances the molecular chain interaction between components, further improves performance and reduces the water absorption of polyamide.

[0025] 4. The polyols and nano-oxides used in this invention have a synergistic effect, which can better promote the carbonization of the flame retardant system during combustion. At the same time, the polyols and nano-oxides have different polarities from the flame retardant, and their interaction can better capture the active acidic substances in the flame retardant, improve the stability of the flame retardant system, improve the flame retardant performance, and reduce the negative effects of the flame retardant on the material system during the processing, so that the material can be produced stably.

[0026] 5. The preparation method of the polyamide composition provided by the present invention is simple, easy to control, and does not require high-end equipment. The equipment used is all general polymer processing equipment, which requires low investment and is conducive to industrial production.

[0027] 6. The polyamide composition prepared by this invention has the characteristics of low water absorption, good dimensional stability, excellent flame retardant properties, and excellent resistance to general chemicals. It can be applied in the automotive, aerospace, electronics and electrical, and home appliance fields. Detailed Implementation

[0028] To facilitate understanding of the present invention, a more comprehensive description will be provided below with reference to specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of the present invention.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0030] The specific information of the raw materials used in the following examples and comparative examples is as follows:

[0031] Polyamide resin, PA6, such as YH800, was purchased from Hunan Yuehua Chemical Co., Ltd.; PA66, such as EPR27, was purchased from Pingdingshan Shenma Company.

[0032] Polyphenylene oxide resins, such as PPO LXR040, Nantong Xingchen Synthetic Materials Co., Ltd.;

[0033] Flame retardants, such as brominated polystyrene, Albemarle Chemicals (Shanghai) Co., Ltd.;

[0034] Synergists, such as antimony trioxide, Hunan Chenzhou Mining Co., Ltd.;

[0035] Antioxidant, Clariant Chemicals (China) Co., Ltd.;

[0036] Polyols, such as dipentaerythritol, Guangzhou Gongxin Chemical Co., Ltd.;

[0037] Nanoparticles, such as nano zinc oxide, Nanjing Haitai Nanomaterials Co., Ltd.;

[0038] Polyphenylene ether grafted with maleic anhydride, Idemitsu Kosan Co., Ltd., Japan;

[0039] Hydrogenated styrene-isoprene copolymer grafted with maleic anhydride, Shenyang Ketong Plastics Co., Ltd.

[0040] Glass fiber, Chongqing International Composite Materials Co., Ltd.;

[0041] Lubricant, Guangdong Xinchengda Technology Co., Ltd.;

[0042] Silane coupling agents, Nanjing Shuguang Chemical Group Co., Ltd.;

[0043] All materials are commercially available, commonly used products.

[0044] It is understood that the above-mentioned raw materials and reagents are merely examples of some specific embodiments of the present invention, making the technical solution of the present invention clearer, and do not mean that the present invention can only use the above-mentioned reagents. The specific scope shall be determined by the claims. In addition, unless otherwise specified, "parts" in the examples and comparative examples refer to parts by weight.

[0045] Any range described in this invention includes the endpoint, any value between the endpoints, and any subrange consisting of the endpoint or any value between the endpoints.

[0046] The parallel twin-screw extruders used in the examples and comparative examples have a single-thread screw with a screw length L to diameter D ratio L / D of 35 to 50. The screw of the parallel twin-screw extruder has two engagement block areas and one reverse thread area.

[0047] Example 1

[0048] (1) Weigh each component according to the proportions in Table 1, and put the dried polyamide resin, polyphenylene ether, polyphenylene ether grafted maleic anhydride, hydrogenated styrene-isoprene copolymer grafted maleic anhydride (SEPS-g-MAH), flame retardant, synergist, polyol, nano oxide, silane coupling agent, antioxidant, and lubricant into a mixer for high-speed mixing at a speed of 500-1500 rpm to obtain a uniformly mixed material;

[0049] (2) The mixture prepared in step (1) is fed into a parallel twin-screw extruder via a feeder, and glass fiber is added to the side (fifth zone) of the parallel twin-screw extruder (nine zones in total) for melt extrusion, granulation, and to obtain low water absorption, low warpage, flame retardant polyamide composition granules.

[0050] In step (1), the drying temperature is 100℃ and the drying time is 4 hours.

[0051] The process parameters of the parallel twin-screw extruder in step (2) include: zone 1 temperature of 250℃, zone 2 temperature of 265℃, zone 3 temperature of 265℃, zone 4 temperature of 265℃, zone 5 temperature of 265℃, zone 6 temperature of 255℃, zone 7 temperature of 255℃, zone 8 temperature of 255℃, die head temperature of 260℃, and screw speed of 350rpm.

[0052] In Example 1, the polyamide resin is PA6; the nano-oxide is nano-zirconia; the glass fiber is type E glass fiber with a diameter of 7 μm; the flame retardant is decabromodiphenyl ethane; the synergist is antimony trioxide; the polyol is pentaerythritol; the antioxidant is a mixture of N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine and tris(2,4-di-tert-butylphenyl)phosphite in a weight ratio of 1:1; and the lubricant is a mixture of calcium stearate and zinc stearate in a weight ratio of 1:1.

[0053] Example 2

[0054] (1) Weigh each component according to the proportions in Table 1, and put the dried polyamide resin, polyphenylene ether, polyphenylene ether grafted maleic anhydride, hydrogenated styrene-isoprene copolymer grafted maleic anhydride (SEPS-g-MAH), flame retardant, synergist, polyol, nano oxide, silane coupling agent, antioxidant, and lubricant into a mixer for high-speed mixing at a speed of 500-1500 rpm to obtain a uniformly mixed material;

[0055] (2) The mixture prepared in step (1) is fed into a parallel twin-screw extruder via a feeder, and glass fiber is added to the side (fifth zone) of the parallel twin-screw extruder (nine zones in total) for melt extrusion, granulation, and to obtain low water absorption, low warpage, flame retardant polyamide composition granules.

[0056] In step (1), the drying temperature is 120℃ and the drying time is 3 hours.

[0057] The process parameters of the parallel twin-screw extruder in step (2) include: zone 1 temperature of 260℃, zone 2 temperature of 280℃, zone 3 temperature of 280℃, zone 4 temperature of 280℃, zone 5 temperature of 275℃, zone 6 temperature of 270℃, zone 7 temperature of 270℃, zone 8 temperature of 270℃, die head temperature of 275℃, and screw speed of 400rpm.

[0058] In Example 2, the polyamide resin is PA66; the nano-oxide is nano-magnesium oxide; the glass fiber is type E glass fiber with a diameter of 7 μm; the flame retardant is decabromodiphenyl ethane; the synergist is a mixture of antimony trioxide and silicon stannate in a weight ratio of 1:3; the polyol is pentaerythritol; the antioxidant is a mixture of octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] in a weight ratio of 1:1; and the lubricant is a mixture of OP wax and zinc stearate in a weight ratio of 1:1.

[0059] Example 3

[0060] (1) Weigh each component according to the proportions in Table 1, and put the dried polyamide resin, polyphenylene ether, polyphenylene ether grafted maleic anhydride, hydrogenated styrene-isoprene copolymer grafted maleic anhydride (SEPS-g-MAH), flame retardant, synergist, polyol, nano oxide, silane coupling agent, antioxidant, and lubricant into a mixer for high-speed mixing at a speed of 500-1500 rpm to obtain a uniformly mixed material;

[0061] (2) The mixture prepared in step (1) is fed into a parallel twin-screw extruder via a feeder, and glass fiber is added to the side (fifth zone) of the parallel twin-screw extruder (nine zones in total) for melt extrusion, granulation, and to obtain low water absorption, low warpage, flame retardant polyamide composition granules.

[0062] In step (1), the drying temperature is 110℃ and the drying time is 5 hours.

[0063] The process parameters of the parallel twin-screw extruder in step (2) include: zone 1 temperature of 260℃, zone 2 temperature of 285℃, zone 3 temperature of 285℃, zone 4 temperature of 285℃, zone 5 temperature of 275℃, zone 6 temperature of 275℃, zone 7 temperature of 275℃, zone 8 temperature of 275℃, die head temperature of 275℃, and screw speed of 450rpm.

[0064] In Example 3, the polyamide resin is PA66; the nano-oxide is a mixture of nano-zirconia and nano-iron oxide in a weight ratio of 3:1; the glass fiber is type E glass fiber with a diameter of 7 μm; the flame retardant is decabromodiphenyl ethane; the synergist is a mixture of antimony trioxide, zinc borate, and silicon stannate in a weight ratio of 1:1:1; the polyol is a mixture of trimethylolethane and pentaerythritol in a weight ratio of 1:2; the antioxidant is a mixture of octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]pentaerythritol ester, and zinc pentaerythritol in a weight ratio of 1:1:1; and the lubricant is a mixture of OP wax and zinc stearate in a weight ratio of 1:2.

[0065] Example 4

[0066] (1) Weigh each component according to the proportions in Table 1, and put the dried polyamide resin, polyphenylene ether, polyphenylene ether grafted maleic anhydride, hydrogenated styrene-isoprene copolymer grafted maleic anhydride (SEPS-g-MAH), flame retardant, synergist, polyol, nano oxide, silane coupling agent, antioxidant, and lubricant into a mixer for high-speed mixing at a speed of 500-1500 rpm to obtain a uniformly mixed material;

[0067] (2) The mixture prepared in step (1) is fed into a parallel twin-screw extruder via a feeder, and glass fiber is added to the side (fifth zone) of the parallel twin-screw extruder (nine zones in total) for melt extrusion, granulation, and to obtain low water absorption, low warpage, flame retardant polyamide composition granules.

[0068] In step (1), the drying temperature is 110℃ and the drying time is 6 hours.

[0069] The process parameters of the parallel twin-screw extruder in step (2) include: zone 1 temperature of 250℃, zone 2 temperature of 275℃, zone 3 temperature of 275℃, zone 4 temperature of 275℃, zone 5 temperature of 270℃, zone 6 temperature of 260℃, zone 7 temperature of 260℃, zone 8 temperature of 260℃, die head temperature of 260℃, and screw speed of 400rpm.

[0070] In Example 4, the polyamide resin is PA6; the nano-oxide is nano-iron oxide; the glass fiber is type E glass fiber with a diameter of 10 μm; the flame retardant is brominated polystyrene; the synergist is a mixture of antimony trioxide and zinc borate in a weight ratio of 3:1; the polyol is pentaerythritol; the antioxidant is a mixture of bis(2,4-di-tert-butylphenyl)pentaerythritol and 2,6-di-tert-butyl-4-4-cresol in a weight ratio of 1:1; and the lubricant is a mixture of OP wax and zinc stearate in a weight ratio of 1:1.

[0071] Example 5

[0072] (1) Weigh each component according to the proportions in Table 1, and put the dried polyamide resin, polyphenylene ether, polyphenylene ether grafted maleic anhydride, hydrogenated styrene-isoprene copolymer grafted maleic anhydride (SEPS-g-MAH), flame retardant, synergist, polyol, nano oxide, silane coupling agent, antioxidant, and lubricant into a mixer for high-speed mixing at a speed of 500-1500 rpm to obtain a uniformly mixed material;

[0073] (2) The mixture prepared in step (1) is fed into a parallel twin-screw extruder via a feeder, and glass fiber is added to the side (fifth zone) of the parallel twin-screw extruder (nine zones in total) for melt extrusion, granulation, and to obtain low water absorption, low warpage, flame retardant polyamide composition granules.

[0074] In step (1), the drying temperature is 120°C and the drying time is 6 hours.

[0075] The process parameters of the parallel twin-screw extruder in step (2) include: zone 1 temperature of 265℃, zone 2 temperature of 280℃, zone 3 temperature of 280℃, zone 4 temperature of 280℃, zone 5 temperature of 265℃, zone 6 temperature of 265℃, zone 7 temperature of 265℃, zone 8 temperature of 265℃, die head temperature of 265℃, and screw speed of 350rpm.

[0076] In Example 5, the polyamide resin is a mixture of PA6 and PA66 in a weight ratio of 1:1; the nano-oxide is nano-iron oxide; the glass fiber is type E glass fiber with a diameter of 7 μm; the flame retardant is polybrominated styrene; the synergist is antimony trioxide; the polyol is pentaerythritol; the antioxidant is a mixture of bis(2,4-di-tert-butylphenyl)pentaerythritol and 2,6-di-tert-butyl-4-4-cresol in a weight ratio of 1:1; and the rosin ester wax and ethylene bis-stearamide in a weight ratio of 1:1.

[0077] Example 6

[0078] (1) Weigh each component according to the proportions in Table 1, and put the dried polyamide resin, polyphenylene ether, polyphenylene ether grafted maleic anhydride, hydrogenated styrene-isoprene copolymer grafted maleic anhydride (SEPS-g-MAH), flame retardant, synergist, polyol, nano oxide, silane coupling agent, antioxidant, and lubricant into a mixer for high-speed mixing at a speed of 500-1500 rpm to obtain a uniformly mixed material;

[0079] (2) The mixture prepared in step (1) is fed into a parallel twin-screw extruder via a feeder, and glass fiber is added to the side (fifth zone) of the parallel twin-screw extruder (nine zones in total) for melt extrusion, granulation, and to obtain low water absorption, low warpage, flame retardant polyamide composition granules.

[0080] In step (1), the drying temperature is 110℃ and the drying time is 4 hours.

[0081] The process parameters of the parallel twin-screw extruder in step (2) include: zone 1 temperature of 235℃, zone 2 temperature of 270℃, zone 3 temperature of 270℃, zone 4 temperature of 270℃, zone 5 temperature of 265℃, zone 6 temperature of 255℃, zone 7 temperature of 255℃, zone 8 temperature of 255℃, die head temperature of 255℃, and screw speed of 400rpm.

[0082] In Example 6, the polyamide resin is PA6; the nano-oxide is a mixture of nano-zinc oxide and nano-magnesium oxide in a weight ratio of 1:1; the glass fiber is type E glass fiber with a diameter of 7 μm; the flame retardant is brominated polystyrene; the synergist is a mixture of antimony trioxide and zinc borate in a weight ratio of 3:1; the polyol is pentaerythritol; the antioxidant is a mixture of bis(2,4-di-tert-butylphenyl)pentaerythritol and 2,6-di-tert-butyl-4-4-cresol in a weight ratio of 1:1; and the lubricant is a mixture of OP wax and zinc stearate in a weight ratio of 1:1.

[0083] The preparation processes and raw material types of Comparative Examples 1-7 are the same as those of Example 6, except for the component ratios, as shown in Table 1.

[0084] Table 1. Summary of Raw Material Composition (by Weight) for Examples and Comparative Examples

[0085]

[0086]

[0087] The polyamide compositions prepared in the above examples and comparative examples were subjected to the following performance tests:

[0088] Tensile properties: Tested according to GB / T 1040-2006 standard, the tensile rate is 50 mm / min;

[0089] Bending performance: Tested according to GB / T 9341-2008 standard, the tensile rate is 2 mm / min;

[0090] Notched impact strength: tested according to GB / T 1843-2008 standard;

[0091] Flame retardant performance: tested according to UL94V0 vertical burning standards; sample dimensions: 125mm*13mm*3.2mm.

[0092] Warpage performance test: The sample size is 100mm*100mm*1.5mm. Visual observation is performed by placing three corners of the square board on the same plane and measuring the vertical distance between the fourth corner and the plane, which is the warpage height.

[0093] Water absorption test: Tested according to GBT 1034-2008 standard, 23℃ / 50% RH;

[0094] The performance test results are shown in Table 2.

[0095] Table 2. Performance overview of the polyamide compositions of the examples and comparative examples.

[0096]

[0097]

[0098] Although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0099] Therefore, the above description is only a preferred embodiment of this application and is not intended to limit the scope of this application; that is, all equivalent modifications made in accordance with the scope of the claims of this application shall be within the protection scope of the claims of this application.

Claims

1. A low-absorption, low-warpage, flame-retardant polyamide composition, characterized in that, It is prepared from the following components in parts by weight: 50-75 parts of polyamide resin; 25-50 parts of polyphenylene ether; 15-60 parts glass fiber; 5.1~10.6 parts of composite compatibilizer; 15-40 parts flame retardant; Synergistic agent 2-15 parts; 0.5-2 parts of nano-oxide; Antioxidant 0.2~0.5 parts; Lubricant 0.5~1.5 parts; The composite compatibilizer is prepared by compounding polyphenylene ether grafted with maleic anhydride, SEPS-g-MAH, polyol and silane coupling agent in a mass ratio of (2~5): (1~3): (1.5~4): (0.1~0.6). The synergist is at least one of antimony trioxide, antimony pentoxide, sodium antimonate, zinc borate, and silicon stannate.

2. The low water absorption, low warpage, flame-retardant polyamide composition according to claim 1, characterized in that, The maleic anhydride grafting rate of the polyphenylene ether grafted with maleic anhydride is 0.8-1.6%; the polyol is at least one of pentaerythritol, dipentaerythritol, trimethylolethane, and tripentaerythritol.

3. The low water absorption, low warpage, flame-retardant polyamide composition according to claim 1, characterized in that, The polyamide resin is selected from at least one of PA66 and PA6, and has a relative viscosity of 2.0 to 2.

8.

4. The low water absorption, low warpage, flame-retardant polyamide composition according to claim 1, characterized in that, The intrinsic viscosity of the polyphenylene ether resin is 0.33–0.45 dL / g.

5. The low water absorption, low warpage, flame-retardant polyamide composition according to claim 1, characterized in that, The nano-oxide is at least one of nano-zinc oxide, nano-magnesium oxide, nano-aluminum oxide, nano-zirconium oxide, and nano-iron oxide, with a particle size of 30~85nm.

6. The low water absorption, low warpage, flame-retardant polyamide composition according to claim 1, characterized in that, The glass fiber is type E glass fiber with a fiber diameter of 7~14μm.

7. The low water absorption, low warpage, flame-retardant polyamide composition according to claim 1, characterized in that, The flame retardant is at least one of brominated polystyrene, polybrominated styrene, decabromodiphenyl ethane, and brominated epoxy resin.

8. The low water absorption, low warpage, flame-retardant polyamide composition according to claim 1, characterized in that, The antioxidant is at least one of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine, bis(2,4-di-tert-butylphenyl)pentaerythritol, zinc pentaerythritol, 2,6-di-tert-butyl-4-4-cresol, and tris(2,4-di-tert-butylphenyl)phosphite; the lubricant is at least one of OP wax, rosin ester wax, ethylene bis-stearamide, calcium stearate, zinc stearate, and aluminum stearate.

9. A method for preparing a low-absorption, low-warpage flame-retardant polyamide composition according to any one of claims 1-8, characterized in that, Includes the following steps: (1) The dried polyamide resin, polyphenylene ether, flame retardant, synergist, nano oxide, composite compatibilizer, antioxidant and lubricant are mixed at high speed to obtain a mixture; (2) The mixture is added to the main feed port of a parallel twin-screw extruder, and glass fiber is added to the side feed port of the parallel twin-screw extruder. After melt extrusion and granulation, low water absorption, low warpage, and flame retardant polyamide composition granules are obtained. The drying temperature in step (1) is 90-120°C, and the drying time is 3-6 hours; The process parameters of the parallel twin-screw extruder mentioned in step (2) include: zone 1 temperature of 230-280℃, zone 2 temperature of 235-285℃, zone 3 temperature of 235-285℃, zone 4 temperature of 240-290℃, zone 5 temperature of 240-290℃, zone 6 temperature of 235-275℃, zone 7 temperature of 235-275℃, zone 8 temperature of 235-275℃, die temperature of 235-275℃, and screw speed of 300-500 rpm.

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