Halogen-free PBT composite material, preparation method and application thereof

Abstract

This invention discloses a halogen-free PBT composite material, its preparation method, and its applications. The halogen-free PBT composite material comprises the following components by weight: 33-47 parts PBT resin; 10-20 parts PBST resin; 8-15 parts diethylphosphonate; 1-6 parts halogen-free synergistic flame retardant; 15-35 parts glass fiber; and 3-10 parts thermoplastic polyester elastomer. This invention, by adding PBST resin and thermoplastic polyester elastomer to a glass fiber-reinforced halogen-free PBT resin system and adjusting the type of halogen-free flame retardant, can produce a PBT composite material with good high and low temperature impact resistance and warpage resistance, while also exhibiting excellent flame retardant properties.

Description

Technical Field

[0001] This invention belongs to the field of engineering plastics technology, specifically relating to a PBT composite material, its preparation method, and its application. Background Technology

[0002] Most components of modern electronic and electrical equipment are made of flammable plastic insulating materials. Due to overheating, leakage, sparks, and aging, these devices may ignite the materials, causing fires and posing a significant threat to people's lives and property. While brominated flame retardants have relatively high flame-retardant effects, the incineration of brominated flame-retardant products produces toxic substances that cause lasting damage to the environment and human health.

[0003] Polybutylene terephthalate (PBT resin), as one of the five major general-purpose engineering plastics, has advantages such as high temperature resistance, oil resistance, chemical corrosion resistance, electrical insulation properties, and short molding cycle, and is widely used in many fields. Currently, with the rapid development of robotics, low-altitude economy, 5G communication, and new energy, more stringent requirements are being placed on the performance of electronic and electrical products. For example, electronic components in robots (especially relays / capacitors / sensors / radar modules) require precise assembly and sealing, demanding that the material accurately replicate the mold without warping or deformation. Long-term performance also needs to be considered, especially under conditions of drastic temperature changes. Plastic products containing metal inserts are subject to continuous high and low temperature cycling forces, which can easily lead to cracking and functional component failure. The addition of halogen-free flame retardants can exacerbate the cracking problem under high and low temperature cycling, while glass fiber, although improving the mechanical properties of the material, can worsen warping issues. Summary of the Invention

[0004] The purpose of this invention is to overcome the defects or shortcomings of existing glass fiber reinforced halogen-free PBT composite materials, such as poor high and low temperature impact resistance and warping problems, and to provide a halogen-free PBT composite material.

[0005] Another object of the present invention is to provide a method for preparing the above-mentioned halogen-free PBT composite material.

[0006] Another object of the present invention is to provide applications of the above-mentioned halogen-free PBT composite material.

[0007] To achieve the above objectives, the present invention employs the following technical solution: A halogen-free PBT composite material, comprising the following components in parts by weight: 33-47 parts of PBT resin; 10-20 parts of PBST resin; 8-15 parts of diethylphosphonate; 1-6 parts of halogen-free synergistic flame retardant; 15-35 parts glass fiber; 3 to 10 parts of thermoplastic polyester elastomer.

[0008] This invention provides a halogen-free PBT composite material. By adding polybutylene succinate-butylene terephthalate copolymer (PBST resin) and thermoplastic polyester elastomer to a glass fiber reinforced halogen-free PBT resin system, the high and low temperature impact resistance of the halogen-free PBT composite material can be effectively improved, and it is less prone to warping and exhibits better flame retardant properties. This may be because PBST resin and PBT resin have similar molecular structures, and PBST resin contains succinic acid blocks, which weaken the crystallization ability of the system and reduce warping. Simultaneously, the combination with thermoplastic polyester elastomer helps to improve the high and low temperature impact resistance.

[0009] It should be noted that, in the halogen-free PBT composite material of the present invention, the PBT resin content is preferably not less than 35 wt%.

[0010] It should be noted that the PBST resin described in this invention is 10 to 20 parts, for example, but not limited to, 10 parts, 10.5 parts, 11 parts, 11.5 parts, 12 parts, 12.5 parts, 13 parts, 13.5 parts, 14 parts, 14.5 parts, 15 parts, 15.5 parts, 16 parts, 16.5 parts, 17 parts, 17.5 parts, 18 parts, 18.5 parts, 19 parts, 19.5 parts, or 20 parts, etc., and the specific point values ​​between the above point values ​​are not exhaustively listed in this invention due to space limitations and for the sake of brevity.

[0011] Preferably, the succinic acid content in the PBST resin is ≥4wt%, for example, but not limited to ≥4wt%, 4.5wt%, 5wt%, 5.5wt%, 6wt%, 6.5wt%, 7wt%, 7.5wt%, 8wt%, 8.5wt%, 9wt%, 9.5wt%, 10wt%, 10.5wt%, 11wt%, 11.5wt%, 12wt%, 12.5wt%, or 13wt%, etc., and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the specific values ​​included in the range will not be exhaustively listed in this invention.

[0012] More preferably, the succinic acid content in the PBST resin is 4wt%~12wt%. When the succinic acid content in the PBST resin is further increased, although the warpage performance is still improved, the crystallization temperature of the entire system decreases, which leads to a decrease in the tensile strength of the obtained halogen-free PBT composite material.

[0013] Specifically, the succinic acid content in the PBST resin was determined by 1H NMR spectroscopy.

[0014] Preferably, the intrinsic viscosity of the PBST resin is 1~1.2 dL / g.

[0015] Specifically, the intrinsic viscosity of the PBST resin was determined according to Method B of standard GB / T 14190-2017.

[0016] Specifically, the solvent for testing the intrinsic viscosity of the PBST resin is phenol and tetrachloroethane (the volume ratio of phenol to tetrachloroethane is 1:1), the dissolution temperature is 100°C, the dissolution time is 0.5 h, and the test temperature is 25°C.

[0017] It should be noted that the PBST resin described in this invention can be homemade or commercially available, and its source is not limited.

[0018] In some preferred embodiments, the PBST resin can be prepared by the following method: Under inert gas protection, succinic acid, terephthalic acid and 1,4-butanediol were esterified under initiator conditions to obtain a prepolymer, which was then polymerized to obtain PBST resin.

[0019] Specifically, the total molar ratio of succinic acid and terephthalic acid to the molar ratio of 1,4-butanediol is 1:(1.1~1.5).

[0020] Specifically, the molar ratio of succinic acid to terephthalic acid is 4:96 to 12:88. The succinic acid content in the prepared PBST resin is adjusted by adjusting the amount of succinic acid and terephthalic acid added.

[0021] Specifically, the inert gas can be nitrogen.

[0022] Specifically, the amount of the initiator added is 0.01% to 0.05% of the total mass of succinic acid, terephthalic acid and 1,4-butanediol.

[0023] Specifically, the initiator may be tetrabutyl titanate.

[0024] Specifically, the esterification reaction is carried out at a temperature of 180~220℃.

[0025] Specifically, the polymerization reaction is carried out at a temperature of 220~250℃.

[0026] Specifically, the polymerization reaction takes 2 to 5 hours.

[0027] Specifically, the polymerization reaction also includes cooling and pelletizing the molten reaction products.

[0028] It should be noted that the thermoplastic polyester elastomer mentioned in this invention is 3 to 10 parts, for example, but not limited to 3 parts, 3.2 parts, 3.5 parts, 3.8 parts, 4 parts, 4.2 parts, 4.5 parts, 4.8 parts, 5 parts, 5.2 parts, 5.5 parts, 5.8 parts, 6 parts, 6.2 parts, 6.5 parts, 6.8 parts, 7 parts, 7.2 parts, 7.5 parts, 7.8 parts, 8 parts, 8.2 parts, 8.5 parts, 8.8 parts, 9 parts, 9.2 parts, 9.5 parts, 9.8 parts, or 10 parts, etc., and the specific values ​​between the above values ​​are not exhaustively listed in this invention due to space limitations and for the sake of brevity.

[0029] Preferably, the Shore hardness of the thermoplastic polyester elastomer is 28D~63D.

[0030] More preferably, the Shore hardness of the thermoplastic polyester elastomer is 40D~55D.

[0031] Specifically, the Shore hardness of the thermoplastic polyester elastomer was measured according to the standard GB / T 2411-2008, and the instantaneous hardness was measured.

[0032] Preferably, the intrinsic viscosity of the PBT resin is 0.5 dL / g to 1.5 dL / g.

[0033] Specifically, the test standard for intrinsic viscosity is GB / T 14190-2017 (Method B), and the test temperature for intrinsic viscosity is 25℃.

[0034] Specifically, the solvent for testing the intrinsic viscosity of the PBT resin is phenol and tetrachloroethane (the volume ratio of phenol to tetrachloroethane is 1:1), the dissolution temperature is 100°C, the dissolution time is 0.5 h, and the test temperature is 25°C.

[0035] It should be noted that the diethylphosphonate mentioned in this invention is 8 to 15 parts, for example, but not limited to, 8 parts, 8.2 parts, 8.5 parts, 8.8 parts, 9 parts, 9.2 parts, 9.5 parts, 9.8 parts, 10 parts, 10.2 parts, 10.5 parts, 10.8 parts, 11 parts, 11.2 parts, 11.5 parts, 11.8 parts, 12 parts, 12.2 parts, 12.5 parts, 12.8 parts, 13 parts, 13.2 parts, 13.5 parts, 13.8 parts, 14 parts, 14.2 parts, 14.5 parts, 14.8 parts, or 15 parts, etc., and the specific values ​​between the above values ​​are not exhaustively listed in this invention due to space limitations and for the sake of brevity.

[0036] Preferably, the diethylphosphonate comprises aluminum diethylphosphonate and / or zinc diethylphosphonate.

[0037] Preferably, the D50 particle size of the diethylphosphonate is 20~50μm.

[0038] Preferably, the halogen-free synergistic flame retardant comprises melamine polyphosphate.

[0039] Preferably, the glass fiber has a single filament diameter of 7~15μm and a chopped length of 3~5mm.

[0040] Preferably, without affecting the high and low temperature toughness, warpage resistance, and flame retardant properties of the halogen-free PBT composite material of the present invention, it further includes 0.1 to 3 parts of other additives.

[0041] Preferably, the other additives include, but are not limited to, antioxidants and / or lubricants.

[0042] In this invention, commonly used antioxidants can be selected, such as, but not limited to, one or more of hindered phenolic antioxidants, phosphite antioxidants, or thioester antioxidants.

[0043] Specifically, the hindered phenolic antioxidants are N,N'-hexamethylene bis(3,5-di-tert-butyl-4-hydroxyphenylpropionamide) (Irganox 1098), pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (Irganox 1010), 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione (antioxidant 1790), 1,6-hexanediol bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (Irganox 259), and octadecyl β-(4-hydroxy-3,5-di-tert-butylphenyl)propionate (Irganox 1098). 1076) or one or more of 3,9-bis{2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)acrylic acid]-1,1-dimethyl}-2,4,8,10-tetraoxaspirocycloundecane (ADK AO-80).

[0044] The phosphite antioxidant is one or more of tris(2,4-di-tert-butylphenyl) phosphite (antioxidant 168), bis(2,6-di-tert-butyl-4-tolyl) pentaerythritol phosphite (PEP-36), or 627A.

[0045] The thioester antioxidant is one or more of the following: distearate thiodipropionate, dodecyl thiodipropionate (antioxidant DLTDP), dilaurate thiodipropionate, or pentaerythritol-based dodecyl thiopropionate.

[0046] The present invention may use commonly used lubricants, such as, but not limited to, one or more of vinyl bis-stearamide, pentaerythritol stearate, polysiloxane, calcium stearate, magnesium stearate, zinc stearate, silicone, PE wax or PP wax.

[0047] Preferably, the halogen-free PBT composite material comprises the following components calculated in parts by weight: 36-42 parts of PBT resin; 12-18 parts of PBST resin; 10-14 parts of diethylphosphonate; 1-6 parts of halogen-free synergistic flame retardant; 15-35 parts glass fiber; 5-9 parts of thermoplastic polyester elastomer; Antioxidant 0.1 to 1 part; Lubricant 0.1~1 part.

[0048] This invention also protects a method for preparing the above-mentioned halogen-free PBT composite material, comprising the following steps: S1. Mix diethylphosphonate and halogen-free synergistic flame retardant evenly to obtain mixture A; S2. Mix all components except glass fiber, diethylphosphonate and halogen-free synergistic flame retardant to obtain mixture B; S3. The mixture A described in step S1, the mixture B described in step S2, and glass fiber are melt-blended and extruded to obtain a halogen-free PBT composite material.

[0049] Preferably, the mixing speed in step S1 is 700~900 rpm, and the mixing time is 2~4 minutes.

[0050] Preferably, the mixing speed in step S2 is 600~800 rpm, and the mixing time is 2~4 minutes.

[0051] Preferably, the extrusion granulation in step S3 is carried out in a twin-screw extruder.

[0052] Preferably, the temperature of the twin-screw extruder is 200-230℃ in zone 1, 240-260℃ in zone 2, 235-255℃ in zone 3, 235-255℃ in zone 4, 235-255℃ in zone 5, 240-260℃ in zone 6, 240-260℃ in zone 7, 220-240℃ in zone 8, 220-240℃ in zone 9, and 240-260℃ in zone 10, and the screw speed of the twin-screw extruder is 200-450 rpm.

[0053] This invention also protects the application of the above-mentioned halogen-free PBT composite material in the preparation of robotics, low-altitude economy, new energy or 5G communication materials; especially for components that require excellent resistance to high and low temperature impacts, low warpage and high flame retardancy.

[0054] The present invention also protects a plastic part comprising a part body made of the above-mentioned halogen-free PBT composite material, and a metal insert disposed in the part body, such as a relay, sensor, connector, and motor.

[0055] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a halogen-free PBT composite material. By adding thermoplastic polyester elastomer and PBST resin to a glass fiber reinforced halogen-free PBT system and adjusting the type of halogen-free flame retardant, the resulting halogen-free PBT composite material exhibits good high and low temperature impact resistance and low warpage performance, while also possessing good flame retardant properties. Attached Figure Description

[0056] Figure 1 This is a schematic diagram of a cross-sectional view of a sample containing a metal insert along the diagonal of a 10mm × 10mm face of the metal. Figure 2 This is a schematic top view of a sample containing metal inserts. Detailed Implementation

[0057] The present invention will be further described in detail below with reference to specific embodiments. These embodiments are only used to explain the present invention and are not intended to limit the scope of the present invention. Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods; the materials and reagents used are commercially available unless otherwise specified.

[0058] 1. Raw materials used in each embodiment and comparative example: PBT resin: PBT resin 1: PBT GX112, intrinsic viscosity of 0.82 dL / g, purchased from Sinopec Yizheng Chemical Fiber Co., Ltd. PBT resin 2: PBT 1100-211M, intrinsic viscosity of 1.00 dL / g, purchased from Changchun Chemical (Jiangsu) Co., Ltd. PBST resin: PBST Resin 1: Succinic acid content 4wt%, self-made; PBST resin 2: succinic acid content 8wt%, self-made; PBST resin 3: succinic acid content 12wt%, self-made; PBST resin 1 to PBST resin 3 were prepared by the following method: Under inert gas (nitrogen) protection, succinic acid, terephthalic acid, and 1,4-butanediol are added to the reactor at a certain molar ratio (the molar ratio of the total moles of succinic acid and terephthalic acid to the moles of 1,4-butanediol is 1:1.2, and the molar ratio of succinic acid to terephthalic acid is 4:96 to 12:88). Simultaneously, tetrabutyl titanate (0.03% of the total mass of succinic acid and terephthalic acid) is added. With stirring, the reaction system is gradually heated to 180℃~220℃ to carry out an esterification reaction to obtain a prepolymer. Subsequently, the reaction system is gradually heated to 220~250℃, and the system pressure is gradually reduced to a vacuum state (<100Pa) to carry out a polycondensation reaction for 2~5 hours. After the reaction is completed, stirring is stopped, and the vacuum is released with inert gas (nitrogen). The molten reaction product is cooled and pelletized to obtain PBST resin. The succinic acid content is changed by adjusting the molar ratio of succinic acid to terephthalic acid.

[0059] PBAT resin: PBAT A400, purchased from Zhuhai Kingfa Biomaterials Co., Ltd.; Diethylphosphonate: Diethylphosphonate 1: Aluminum diethylphosphonate, EXOLIT OP 1230, purchased from Clariant Chemicals (China) Co., Ltd.; Diethylphosphonate 2: Aluminum diethylphosphonate, ADP-33P, purchased from Qingdao Oprui New Materials Co., Ltd.; Halogen-free flame retardant: Inorganic aluminum hypophosphite, Lydorflame 5300, purchased from Guangdong Shunde Tongcheng New Material Technology Co., Ltd.; Halogen-free synergistic flame retardant: melamine polyphosphate, BUDIT 3141, purchased from Budenheim GmbH, Germany; Glass fiber: HMG436S-10-4.0, monofilament diameter is 10μm, chopped length is 4mm, purchased from Taishan Glass Fiber Co., Ltd. Thermoplastic polyester elastomer: Thermoplastic polyester elastomer 1: H28DMG, Shore hardness 28D, purchased from Jiangyin Hechuang Elastomer New Material Technology Co., Ltd. Thermoplastic polyester elastomer 2: H40DMG, Shore hardness 40D, purchased from Jiangyin Hechuang Elastomer New Material Technology Co., Ltd. Thermoplastic polyester elastomer 3: H45DMG, Shore hardness 45D, purchased from Jiangyin Hechuang Elastomer New Material Technology Co., Ltd. Thermoplastic polyester elastomer 4: H55DMG, Shore hardness 55D, purchased from Jiangyin Hechuang Elastomer New Material Technology Co., Ltd. Thermoplastic polyester elastomer 5: H63DMG, Shore hardness 63D, purchased from Jiangyin Hechuang Elastomer New Material Technology Co., Ltd. Toughening agent: Ethylene-acrylate copolymer, ELVALOY AC RESIN 1125, purchased from Dow Chemical; Other adjuvants: Antioxidant: A compound of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris(2,4-di-tert-butylphenyl) phosphite in a mass ratio of 1:1; Antioxidants: A compound of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:2, both of which are commercially available; Lubricant: Pentaerythritol stearate, commercially available; It should be noted that the same raw materials were used in the parallel experiments in the examples and comparative examples.

[0060] 2. The halogen-free PBT composite materials for each embodiment and comparative example were prepared according to the formulations in Tables 1-2 and the following preparation methods: S1. Mix diethylphosphonate and halogen-free synergistic flame retardant at 700-900 rpm for 2-4 minutes to obtain mixture A; S2. Mix all components except glass fiber, diethylphosphonate and halogen-free synergistic flame retardant at 600-800 rpm for 2-4 minutes to obtain mixture B; S3. The mixture A described in step S1, the mixture B described in step S2, and glass fiber are melt-blended and extruded and granulated using a twin-screw extruder to obtain a halogen-free PBT composite material; the temperature of the twin-screw extruder is 200-230℃ in zone 1, 240-260℃ in zone 2, 235-255℃ in zone 3, 235-255℃ in zone 4, 235-255℃ in zone 5, 240-260℃ in zone 6, 240-260℃ in zone 7, 220-240℃ in zone 8, 220-240℃ in zone 9, and 240-260℃ in zone 10; the screw speed of the twin-screw extruder is 200-450 rpm.

[0061] 3. Performance Testing: (1) Flame retardant performance test: The halogen-free PBT composite materials in each example and comparative example were injection molded into 125mm×13mm×0.75mm strips and tested according to the UL94-2023 vertical burning standard; (2) Warpage performance test: The halogen-free PBT composite materials prepared in each example and comparative example were injection molded into a 30mm×20mm×10mm cuboid box without a lid (missing the 30mm×20mm face, with a thickness of 1mm). The concave dimensions of the 30mm direction of the 30mm×20mm face of the shell were recorded, and the average value was recorded as X (mm). (3) High and low temperature impact resistance test: The halogen-free PBT composite materials prepared in each example and comparative example were injection molded into samples containing metal inserts. The total size of the sample after injection molding was 20mm×20mm×24mm, of which the metal (copper) size was 10mm×10mm×20mm (gray part). A schematic diagram of the metal insert sample is shown below. Figures 1-2 As shown, the sample was placed in a 125℃ test chamber for 0.5 hours, then quickly switched to a -40℃ test chamber for 0.5 hours, and then quickly switched back to a 125℃ test chamber for 0.5 hours. This process was repeated, with each switch taking less than 5 seconds. One cycle consisted of placing the sample at 125℃ for 0.5 hours and at -40℃ for 0.5 hours. The cycle continued until cracks appeared in the plastic part of the sample, and the number of cycles was recorded.

[0062] Examples 1-10 and Comparative Examples 1-5 Table 1. Amounts (parts by weight) and properties of each component in the halogen-free PBT composite materials of Examples 1-8

[0063] Table 2. Amounts (parts by weight) and properties of each component in the halogen-free PBT composite materials of Examples 9-10 and Comparative Examples 1-5

[0064] As can be seen from Tables 1 and 2, the halogen-free PBT composite material prepared by the present invention has good high and low temperature impact resistance, low warpage and good flame retardant properties. Specifically, all of them can achieve V-0 flame retardancy, the warpage performance is ≤0.2mm, and the number of high and low temperature impact tests is ≥1000.

[0065] As can be seen from Comparative Examples 1 and 2, the warpage properties and high and low temperature impact resistance of the halogen-free PBT composite material obtained without adding PBST resin or thermoplastic polyester elastomer are significantly worse than those of the examples.

[0066] As can be seen from Comparative Example 3, if other resins are used instead of the PBST resin of the present invention, the halogen-free PBT composite material obtained has improved high and low temperature impact resistance, but it is still significantly worse than that of the example, and the warpage performance is significantly worse.

[0067] As can be seen from Comparative Example 4, if a conventional toughening agent is used instead of the thermoplastic polyester elastomer of the present invention, the high and low temperature impact resistance of the resulting halogen-free PBT composite material is significantly worse than that of the example.

[0068] As can be seen from Comparative Example 5, if other halogen-free flame retardants are used, the warpage performance and high and low temperature impact resistance of the prepared halogen-free PBT composite material are significantly worse than those of the example.

[0069] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A halogen-free PBT composite material, characterized in that, Includes the following components, calculated in parts by weight: 33-47 parts of PBT resin; 10-20 parts of PBST resin; 8-15 parts of diethylphosphonate; 1-6 parts of halogen-free synergistic flame retardant; 15-35 parts glass fiber; 3 to 10 parts of thermoplastic polyester elastomer.

2. The halogen-free PBT composite material according to claim 1, characterized in that, The PBST resin contains ≥4wt% succinic acid; preferably, the PBST resin contains 4wt%~12wt% succinic acid.

3. The halogen-free PBT composite material according to claim 1, characterized in that, The Shore hardness of the thermoplastic polyester elastomer is 28D~63D; preferably, the Shore hardness of the thermoplastic polyester elastomer is 40D~55D.

4. The halogen-free PBT composite material according to claim 1, characterized in that, The intrinsic viscosity of the PBT resin is 0.5 dL / g to 1.5 dL / g.

5. The halogen-free PBT composite material according to claim 1, characterized in that, The diethylphosphonate includes aluminum diethylphosphonate and / or zinc diethylphosphonate; the halogen-free synergistic flame retardant includes melamine polyphosphate.

6. The halogen-free PBT composite material according to claim 1, characterized in that, The glass fiber has a single filament diameter of 7~15μm and a chopped length of 3~5mm.

7. The halogen-free PBT composite material according to claim 1, characterized in that, It also includes 0.1 to 3 parts of other additives; said other additives include lubricants and / or antioxidants.

8. A method for preparing the halogen-free PBT composite material according to any one of claims 1 to 7, characterized in that, Includes the following steps: S1. Mix diethylphosphonate and halogen-free synergistic flame retardant evenly to obtain mixture A; S2. Mix all components except glass fiber, diethylphosphonate and halogen-free synergistic flame retardant to obtain mixture B; S3. The mixture A described in step S1, the mixture B described in step S2, and glass fiber are melt-blended and extruded to obtain a halogen-free PBT composite material.

9. The application of the halogen-free PBT composite material according to any one of claims 1 to 7 in the preparation of robot parts, low-altitude economic devices, new energy materials or 5G communication materials.

10. A plastic part, characterized in that, It includes a component body made of the halogen-free PBT composite material according to any one of claims 1 to 7, and a metal insert disposed in the component body.

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