Polyphthalamide material as well as preparation method and application thereof

Abstract

The invention relates to a polyphthalamide material as well as a preparation method and application thereof. The polyphthalamide material comprises the following components in parts by mass: 45-55 parts of polyphthalamide; 4-6 parts of an inorganic synergistic flame retardant; 12 to 18 parts of a halogen fire retardant; 28-32 parts of a functional short fiber combination; 0.9 to 1.1 parts of an auxiliary agent; wherein the functional short fiber combination is composed of enhanced short fibers and conductive short fibers. Thus, by adopting the synergistic effect of the components, high temperature resistance, UL94 V0-level flame retardance, electric conduction and electromagnetic interference resistance are integrated at the same time, the mechanical property is excellent, and the technical problems that in an existing polyphthalamide modification technology, single-function modification cannot meet the requirements of multiple scenes, and the mechanical property is seriously degraded due to superposition of multiple properties are effectively solved.

Description

Technical Field

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

[0002] Polyphthalamide (PPA) is a type of semi-aromatic polyamide synthesized from terephthalic acid (TPA) or isophthalic acid (IPA) as the main dicarboxylic acid raw materials. The aromatic ring structure introduced into its molecular chain endows it with excellent heat resistance, mechanical properties, chemical corrosion resistance and low water absorption. At the same time, its dimensional stability is significantly better than that of aliphatic polyamides, and it has great potential for application in automotive electronics, high-end electrical appliances, aerospace and other fields.

[0003] With the rapid development of electronic device integration, miniaturization and new energy vehicle technology, the market has put forward multi-performance integration requirements for PPA materials, including high temperature resistance, flame retardancy, conductivity and electromagnetic interference resistance. In particular, the materials need to have characteristics such as moderate density, low moisture content and stable mechanical properties to meet the stringent requirements of high-end electronic components and automotive core components.

[0004] In the existing technology, there are obvious shortcomings in PPA modification research: on the one hand, single-function modification (such as flame retardancy only or conductivity only) is difficult to meet the multi-performance requirements of complex scenarios. For example, flame-retardant modified PPA often lacks conductivity, while conductive modified PPA is prone to insufficient flame retardancy. On the other hand, existing multi-performance modification processes often lead to damage to the original temperature resistance and mechanical properties of PPA, and uneven dispersion of fillers can easily cause performance fluctuations. At the same time, existing processes have poor compatibility with industrial mass production equipment, making it difficult to achieve large-scale production. Summary of the Invention

[0005] Therefore, it is necessary to provide a polyphthalamide material that integrates high temperature resistance, flame retardancy, electrical conductivity, electromagnetic interference resistance, and good mechanical properties, as well as its preparation method and application.

[0006] This application provides a polyphthalamide material comprising the following components in parts by weight: 45-55 parts of polyphthalamide; 4-6 parts of inorganic synergistic flame retardant; 12-18 parts of halogenated fire retardant; Functional short fiber blend of 28-32 parts; Additives: 0.9-1.1 parts; The functional short fiber assembly consists of reinforcing short fibers and conductive short fibers, wherein the mass ratio of reinforcing short fibers to conductive short fibers is "8-12": "18-22".

[0007] In one embodiment, the 0.9-1.1 parts of additives include 0.5-0.7 parts of lubricant, 0.15-0.25 parts of antioxidant, and 0.15-0.25 parts of nucleating agent.

[0008] In one embodiment, the lubricant is a fatty acid ester or a polyolefin wax lubricant; In one embodiment, the antioxidant is a compound of primary antioxidant 1098 and phosphite auxiliary antioxidant in a mass ratio of 2:1. In one embodiment, the nucleating agent is adipic acid-1,6-bis(2-benzoylhydrazine), and the difference between the nucleating agent and the Hansen solubility parameter of the polyphthalamide matrix is ​​≤1.5 (J / cm³)¹ / ².

[0009] In one embodiment, the inorganic synergistic flame retardant includes at least one of zinc borate, sodium antimonate, and magnesium hydroxide; preferably, the inorganic synergistic flame retardant is nano zinc borate with a particle size of 50-100 nm. In one embodiment, the halogenated flame retardant is a brominated flame retardant or a chlorinated flame retardant; preferably, the halogenated flame retardant is a brominated epoxy resin derivative with a number average molecular weight of 3000-5000 g / mol and a bromine content of 58%-62%; In one embodiment, the mass ratio of halogenated fire retardant to inorganic synergistic flame retardant is 3:1.

[0010] In one embodiment, the reinforcing short fiber includes at least one of glass short fiber and basalt short fiber; the surface of the reinforcing short fiber is coated with γ-aminopropyltriethoxysilane coupling agent, and the coating amount is 0.5%-1.0% of the short fiber mass; In one embodiment, the conductive short fiber includes at least one of carbon fiber and metal-coated short fiber; the surface of the conductive short fiber is subjected to plasma etching treatment with an etching depth of 50-200 nm. In one embodiment, the reinforced short fiber is Taishan short fiber, and the conductive short fiber is antistatic short fiber; In one embodiment, the reinforced short fiber is a glass short fiber (Taishan short fiber) with a diameter of 10-20 μm and a length of 3-5 mm, and its surface is coated with a γ-aminopropyltriethoxysilane coupling agent, with a coating amount of 0.5%-1.0% of the short fiber mass; the conductive short fiber is a metal-coated antistatic short fiber with a diameter of 5-15 μm and a length of 1-3 mm, and its surface is treated with plasma etching to an etching depth of 50-200 nm.

[0011] In one embodiment, the polyphthalamide is 50 parts by weight; the inorganic synergistic flame retardant is 5 parts by weight; the halogenated fire retardant is 15 parts by weight; and the mass ratio of the reinforced short fiber to the conductive short fiber is 1:2. In one embodiment, the performance indicators of the polyphthalamide material meet the following requirements: density 1.478-1.536 g / cm³, melt flow index 20-25 g / 10 min (test conditions: 290℃, 2.16 kg, test method ASTM D1238), flexural strength ≥160 MPa, notched impact strength ≥50 J / m, tensile strength ≥145 MPa, heat deflection temperature (0.45 MPa) 250-260℃, heat deflection temperature (1.82 MPa) 220-230℃, flame retardancy reaching UL94 V0 level (3.2 mm), and volume resistivity ≤10 Ω·cm. 6 Ω·cm, electromagnetic shielding effectiveness ≥20dB in the 8-18GHz frequency band, moisture content ≤0.1%; In one embodiment, the conductive short fiber has a diameter of 5-15 μm and a length of 1-3 mm; In one embodiment, the reinforced short fiber has a diameter of 10-20 μm and a length of 3-5 mm.

[0012] In one embodiment, the terminal amino content of the polyphthalamide is 30-50 mmol / kg, which forms an interfacial hydrogen bond cluster with the hydroxyl and carboxyl groups in the functional short fiber combination, and the total interaction energy is 20-30 kJ / mol. In one embodiment, the polyphthalamide material further includes 1 part of a colorant, which is a black masterbatch with a carbon black content of 30%.

[0013] Secondly, this application provides a method for preparing the polyphthalamide material as described in any of the above embodiments, characterized in that the preparation method includes the following steps: Polyphthalamide resin, lubricant, antioxidant, and nucleating agent are mixed in a high-speed mixer at a speed of 800-1200 r / min for 5-8 min to obtain a premix. The premixed material is added to the main feed inlet of the twin-screw extruder at a feed rate of 200 kg / h. The inorganic synergistic flame retardant and halogenated fire retardant are added through the side feed inlet in the fifth section. When the melt pressure reaches 15-20 MPa, the functional short fiber combination side feed is activated, with the short fiber feed rate to main feed ratio at 1:3.5. The temperatures of each section of the twin-screw extruder from the feed inlet to the die head are as follows: Section 1 310-320℃, Section 2 300-310℃, Section 3 300-310℃. 0℃, fourth stage 290-300℃, fifth stage 280-290℃, sixth stage 270-280℃, seventh stage 260-270℃, eighth stage 250-260℃, ninth stage 240-250℃, die head temperature 300-320℃; screw speed 300-320r / min, vacuum degree -0.09~-0.095MPa, melt pressure controlled at 15-25MPa, and actual melt temperature 285-290℃.

[0014] In one embodiment, the method for preparing the polyphthalamide material includes the following steps: (1) Raw material pretreatment: The polyphthalamide resin was pre-dried by hot air at 120-130℃ for 3-4 hours, and then vacuum dried at 120℃ for 2-3 hours. The moisture content of the dried material was ≤0.1%. The reinforced short fiber was placed in a 2% (w / w) aqueous solution of γ-aminopropyltriethoxysilane (pH adjusted to 3.5-4.5 with acetic acid), stirred at 70℃ for 45 minutes, filtered, and dried at 120℃ for 3 hours. The conductive short fiber was subjected to plasma etching treatment with an etching power of 120W and a time of 8 minutes. The etching gas was a mixture of argon and oxygen (volume ratio 3:1), the etching vacuum was 10-30Pa, the argon flow rate was 20sccm, and the oxygen flow rate was 7sccm. (2) Premixing: Add the pretreated polyphthalamide resin, lubricant, antioxidant, nucleating agent and colorant to a high-speed mixer (model: SHR-1000A), with a speed of 800-1200 r / min, a time of 5-8 min, and a discharge temperature of ≤50℃ to obtain the premixed material; (3) Segmented melt blending: The premixed material is added to the main feed port of the twin-screw extruder (model: TE-75, length-to-diameter ratio 40:1) at a feed rate of 200 kg / h; the inorganic synergistic flame retardant and halogenated fire retardant are added in the fifth segment through the side feed port. When the melt pressure reaches 15-20 MPa, the functional short fiber combination side feed is turned on, and the short fiber feeding rate is 1:3.5 to the main feed rate; the temperature of each segment of the twin-screw extruder from the feed port to the die head is as follows: the first segment 310-320℃, the second segment 300- The temperature ranges as follows: 310℃ (first stage), 300-310℃ (second stage), 290-300℃ (third stage), 280-290℃ (fourth stage), 270-280℃ (sixth stage), 260-270℃ (seventh stage), 250-260℃ (eighth stage), 240-250℃ (ninth stage), and die head temperature 300-320℃; screw speed 300-320 r / min; vacuum degree -0.09~-0.095 MPa; melt pressure controlled at 15-25 MPa; and measured melt temperature 285-290℃. (4) Granulation and post-processing: After the extrudate is cooled in a water cooling tank (water temperature 25-30℃, cooling length 3m), it is granulated in a pelletizer (cutter speed 800-1000r / min) with a particle length of 2-3mm and a roundness of ≥95%. A 20-mesh vibrating screen (screen aperture 0.85mm) is used to screen the particles to remove long strips and broken pieces with a screening efficiency of ≥98%. The sieved particles are stored in a drying silo (temperature 80-90℃, relative humidity ≤30%) for a storage period of ≤72h to obtain polyphthalamide material.

[0015] Thirdly, this application provides the application of the polyphthalamide material as described in any of the above embodiments, or the polyphthalamide material prepared by the preparation method described in any of the above embodiments, in electronic devices, including personal computers, digital cameras, and mobile phones.

[0016] The above-mentioned polyphthalamide material has a mass ratio of 45-55 parts of polyphthalamide as the matrix. By adding 4-6 parts of inorganic synergistic flame retardant (such as zinc borate) and 12-18 parts of halogenated flame retardant (such as brominated flame retardant), the material can achieve UL94 V0 flame retardant performance through the synergistic mechanism of gas phase flame retardancy and condensed phase flame retardancy. This solves the problem of insufficient function or deterioration of mechanical properties caused by the addition of a single flame retardant. By adding 28-32 parts of a functional short fiber combination, which consists of reinforcing short fibers and conductive short fibers, with a mass ratio of reinforcing short fibers to conductive short fibers of "8-12": "18-22", the reinforcing short fibers (such as glass short fibers (Taishan short fibers)) significantly improve the bending strength and tensile strength of the material through physical reinforcement; the conductive short fibers (such as metal-coated short fibers with antistatic function) achieve conductivity by constructing a continuous conductive network, and at the same time, this network can effectively shield electromagnetic interference signals, thus solving the contradiction in the prior art of simultaneously achieving conductive modification and flame retardancy and mechanical properties. Detailed Implementation

[0017] To facilitate understanding of the present invention and to make the above-mentioned objects, features, and advantages of the present invention more apparent, a detailed description is provided below in conjunction with specific embodiments of the present invention. Many specific details are set forth in the following description to provide a thorough understanding of the present invention, and preferred embodiments are given. 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. The present invention can be implemented in many other ways different from those described herein, and similar modifications can be made by those skilled in the art without departing from the spirit of the invention; therefore, the present invention is not limited to the specific embodiments disclosed below. 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 is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0018] In a first aspect, this application provides a polyphthalamide material comprising the following components in parts by weight: 45-55 parts of polyphthalamide; 4-6 parts of inorganic synergistic flame retardant; 12-18 parts of halogenated fire retardant; Functional short fiber blend of 28-32 parts; Additives: 0.9-1.1 parts; The functional short fiber assembly consists of reinforcing short fibers and conductive short fibers, wherein the mass ratio of reinforcing short fibers to conductive short fibers is "8-12": "18-22".

[0019] The above-mentioned polyphthalamide material has a mass ratio of 45-55 parts of polyphthalamide as the matrix. By adding 4-6 parts of inorganic synergistic flame retardant (such as zinc borate) and 12-18 parts of halogenated flame retardant (such as brominated flame retardant), the material can achieve UL94 V0 flame retardant performance through the synergistic mechanism of gas phase flame retardancy and condensed phase flame retardancy. This solves the problem of insufficient function or deterioration of mechanical properties caused by the addition of a single flame retardant. By adding 28-32 parts of a functional short fiber combination, which consists of reinforcing short fibers and conductive short fibers, with a mass ratio of reinforcing short fibers to conductive short fibers of "8-12": "18-22", the reinforcing short fibers (such as glass short fibers (Taishan short fibers)) significantly improve the bending strength and tensile strength of the material through physical reinforcement; the conductive short fibers (such as metal-coated short fibers with antistatic function) achieve conductivity by constructing a continuous conductive network, and at the same time, this network can effectively shield electromagnetic interference signals, thus solving the contradiction in the prior art of simultaneously achieving conductive modification and flame retardancy and mechanical properties.

[0020] In this application, polyphthalamide (PPA), as a semi-aromatic polyamide, possesses high heat resistance and low water absorption due to its aromatic ring structure in its molecular chain, providing a stable matrix for multi-performance modification and avoiding thermal degradation during high-temperature processing. In one embodiment, the terminal amino content of the polyphthalamide is 30-50 mmol / kg, and it forms hydrogen bonds with the hydroxyl and carboxyl groups in the functional short fiber combination, with a hydrogen bond binding energy of 20-30 kJ / mol. Thus, when the terminal amino content of polyphthalamide is controlled at 30-50 mmol / kg, it can form a binding energy of 20-30 kJ / mol with the reinforcing short fibers (containing hydroxyl groups on the surface after coating with a coupling agent) and conductive short fibers (generating carboxyl groups on the surface after plasma etching) in the functional short fiber combination. The stabilizing hydrogen bonds significantly enhance the interfacial bonding between the polyphthalamide matrix and the short fibers, preventing fiber delamination under external forces, while also maintaining interfacial flexibility and reducing stress concentration. For reinforced short fibers, hydrogen bonding strengthens their mechanical support within the matrix, further improving flexural and tensile strength and enhancing stability. For conductive short fibers, the tight interfacial bonding prevents breakage of the conductive network due to interfacial voids, ensuring the continuity of the conductive pathway and maintaining the material's volume resistivity at ≤10 Ω·cm. 6With a lower Ω·cm, the material exhibits more reliable electrical conductivity and electromagnetic interference resistance. This design effectively solves the problems of fluctuating mechanical properties and unstable electrical conductivity caused by the weak interfacial bonding between traditional short fibers and the polyphthalamide matrix. It further ensures the synergistic integration of high temperature resistance, flame retardancy, electrical conductivity, electromagnetic interference resistance, and excellent mechanical properties, thereby improving the material's reliability under complex working conditions.

[0021] In one embodiment, the 0.9-1.1 parts of additives include 0.5-0.7 parts of lubricant, 0.15-0.25 parts of antioxidant, and 0.15-0.25 parts of nucleating agent. For example, the lubricant is a fatty acid ester lubricant, which has excellent lubrication effect and good compatibility with PPA; the antioxidant is a compound of primary antioxidant 1098 and phosphite ester auxiliary antioxidant in a mass ratio of 2:1, which can effectively inhibit thermo-oxidative aging of PPA during high-temperature processing; the nucleating agent is adipic acid-1,6-bis(2-benzoylhydrazine), and the difference in Hansen solubility parameter between the nucleating agent and the PPA matrix is ​​≤1.5 (J / cm³)¹ / ², ensuring excellent compatibility and avoiding the agglomeration of nucleating agent from affecting material properties. For example, the antioxidant is composed of antioxidant 1098 and phosphite-based auxiliary antioxidants in a mass ratio of 2:1, and the difference in compatibility parameter (Hansen solubility parameter) between the nucleating agent and the polyphthalamide matrix is ​​≤1.5 (J / cm³)¹ / ². Thus, the 2:1 mixture of antioxidant 1098 and phosphite-based auxiliary antioxidants synergistically inhibits the high-temperature oxidative degradation of polyphthalamide, ensuring its high-temperature stability. The difference in solubility parameter between the nucleating agent and the polyphthalamide matrix is ​​≤1.5, indicating excellent compatibility, refining crystals and improving processing fluidity. The two work synergistically to ensure the stable integration of multiple properties throughout the material's lifecycle.

[0022] In one embodiment, the inorganic synergistic flame retardant includes at least one of zinc borate, sodium antimonate, and magnesium hydroxide; for example, the halogenated flame retardant is a brominated flame retardant or a chlorinated flame retardant. In one embodiment, the reinforcing short fiber includes at least one of glass short fiber and basalt short fiber, and the conductive short fiber includes at least one of carbon fiber and metal-coated short fiber. For example, the inorganic synergistic flame retardant is zinc borate, and the halogenated flame retardant is a brominated flame retardant, such as polybrominated styrene, brominated epoxy resin derivatives, etc. Thus, when zinc borate is used as the inorganic synergistic flame retardant and the brominated flame retardant is used as the halogenated flame retardant, the two work together through the synergistic mechanism of the brominated flame retardant capturing combustion free radicals in the gas phase and the zinc borate condensed phase forming a heat-insulating carbon layer and a protective layer, so that the material achieves UL94 V0 without destroying the high temperature resistance brought by the rigid benzene ring of polyphthalamide (PPD). The material exhibits superior flame retardant performance and significantly reduced smoke generation. Furthermore, zinc borate and brominated flame retardants demonstrate excellent compatibility with the benzene ring-amide bond structure and hexamethylenediamine aliphatic segments of polyphthalamide, respectively, resulting in uniform dispersion. This ensures the material's processing fluidity while maintaining excellent mechanical properties such as increased flexural strength and notched impact strength through the "dual reinforcing skeleton" effect of the char layer and reinforcing short fibers. This effectively solves the problem of existing flame-retardant modified polyphthalamides struggling to simultaneously achieve good temperature resistance, mechanical properties, and flame retardancy. For example, the inorganic synergistic flame retardant is nano-zinc borate with a particle size of 50-100 nm, and a mass ratio of 1:3 with the halogenated flame retardant. The nano-sized particles provide an ultra-large specific surface area, allowing for uniform dispersion within the intermolecules of PPA. The zinc oxide and boric acid generated upon thermal decomposition rapidly form a dense, heat-insulating char layer, enhancing the condensed phase flame retardant effect. By using a halogenated fire retardant (6700 halogenated fire retardant, a brominated epoxy resin derivative) and an inorganic synergistic flame retardant (nano zinc borate) in a 3:1 mass ratio, the synergistic efficiency is high. Through the synergistic effect of gas-phase flame retardancy (bromine free radicals capture combustion-active substances) and condensed-phase flame retardancy (zinc borate decomposes to form a dense heat-insulating char layer), only 16-24 parts of flame retardant are needed to achieve UL94 V0 flame retardant performance without damaging the heat-resistant structure of the matrix. At the same time, the excellent char-forming properties of PPA itself are used to enhance the flame retardant effect and avoid the damage to mechanical properties caused by excessive flame retardant.

[0023] In one embodiment, the halogenated flame retardant is a brominated epoxy resin derivative with a number average molecular weight of 3000-5000 g / mol and a bromine content of 58%-62%; the inorganic synergistic flame retardant is nano-zinc borate with a particle size of 50-100 nm, and the mass ratio of the inorganic synergistic flame retardant to the halogenated flame retardant is 1:3. Thus, using a brominated epoxy resin derivative with a number average molecular weight of 3000-5000 g / mol and a bromine content of 58%-62% as the halogenated flame retardant ensures excellent compatibility with the polyphthalamide matrix, preventing the migration and precipitation of low molecular weight flame retardants or uneven dispersion of high molecular weight flame retardants. The high bromine content also ensures high-efficiency gas-phase flame retardant activity, rapidly releasing bromine free radicals to capture active substances during combustion. Combined with a particle size of 50-100 nm... The nano-zinc borate (an inorganic synergistic flame retardant) possesses a nano-sized particle size that provides an ultra-large specific surface area, allowing it to be uniformly dispersed within the molecular gaps of polyphthalamide. Upon thermal decomposition, the resulting zinc oxide and boric acid rapidly form a dense, heat-insulating char layer, enhancing the flame-retardant effect of the condensed phase. When combined in a 1:3 mass ratio, it achieves precise synergy between efficient gas-phase flame suppression and condensed-phase heat insulation and oxygen barrier properties. With controllable total flame-retardant system addition, the material easily achieves UL94 V0 flame-retardant performance, while reducing smoke density and toxic gas release. Furthermore, this flame-retardant combination exhibits excellent compatibility with the benzene ring-amide bond structure of polyphthalamide, without disrupting the heat-resistant framework of the matrix, ensuring the material's high temperature resistance remains unaffected. It also synergizes with functional short fibers, avoiding mechanical property degradation caused by flame retardant addition. This effectively solves the technical pain points of traditional flame-retardant systems—low flame-retardant efficiency, poor compatibility, and sacrifice of core matrix properties—further guaranteeing the stability of the material's multi-performance integration. For example, the halogenated fire retardant is 6700 halogenated fire retardant; for example, the melt flow index of the polyphthalamide material is 25-30 g / 10min, test conditions: 330℃, 2.16kg, test method is ASTM D1238; for example, the flexural strength of the polyphthalamide material is ≥180MPa, notched impact strength is ≥58J / m, tensile strength is ≥165MPa; for example, the flame retardant performance of the polyphthalamide material reaches UL94 V0 level; for example, the volume resistivity of the polyphthalamide material is ≤10 Ω·cm. 6 Ω.cm.

[0024] In one embodiment, the reinforcing short fiber is a chopped fiber, such as Taishan short fiber (commercially available chopped fiber from Taishan Glass Fiber (Taiyuan) Co., Ltd.), and the conductive short fiber is an antistatic short fiber. For example, the reinforcing short fiber has a diameter of 10-20 μm and a length of 3-5 mm, and its surface is coated with a γ-aminopropyltriethoxysilane coupling agent, with a coating amount of 0.5%-1.0% of the short fiber mass. For example, the conductive short fiber has a diameter of 5-15 μm and a length of 1-3 mm, and its surface is treated with plasma etching to a depth of 50-200 nm. Thus, by optimizing the size parameters of the short fiber and the surface modification process, the synergy between the conductive network and mechanical reinforcement is achieved, solving the problem of mechanical property degradation caused by uneven dispersion of traditional conductive fillers. In this embodiment, reinforced short fibers with a diameter of 10-20 μm, a length of 3-5 mm, and a surface coated with 0.5%-1.0% γ-aminopropyltriethoxysilane coupling agent are used. Their size can form an effective mechanical support skeleton in the polyphthalamide (PPD) matrix. The coupling agent forms a chemical bond with the amide bond of PPD, which greatly improves the interfacial bonding force, reduces stress concentration, and significantly enhances the bending strength and tensile strength of the material. Meanwhile, conductive short fibers with a diameter of 5-15 μm, a length of 1-3 mm, and a surface etched by plasma to a depth of 50-200 nm not only ensure conductive overlap efficiency through an appropriate aspect ratio, but also strengthen the interfacial bonding with the PPD matrix due to the increased surface roughness and active sites caused by etching. At the same time, it promotes effective overlap between conductive short fibers, constructs a continuous and efficient conductive network, and makes the material have a low volume resistivity, achieving excellent conductivity and anti-electromagnetic interference performance. The synergy of these two technologies not only solves the problem of mechanical property degradation caused by uneven dispersion and weak interfacial bonding of traditional short fibers, but also overcomes the technical bottleneck of simultaneously achieving conductive modification and mechanical reinforcement. This allows the material to simultaneously achieve conductivity and electromagnetic interference resistance on the basis of high mechanical properties, meeting the multi-performance integration requirements of high-end applications. For example, the mass ratio of the reinforced short fiber to the conductive short fiber is 1:2. With this 1:2 mass ratio, on the one hand, the reinforced short fiber can form a sufficient mechanical support skeleton in the polyphthalamide matrix, ensuring excellent mechanical properties such as enhanced bending strength and tensile strength; on the other hand, the proportion of conductive short fiber is sufficient to construct a continuous and efficient conductive network in the matrix, achieving good conductivity and electromagnetic interference resistance. This ratio balances the needs of mechanical reinforcement and conductivity, avoiding the defects of conductive network breakage or mechanical property degradation caused by an excessive proportion of reinforced short fiber. Ultimately, the material achieves simultaneous conductivity and electromagnetic interference resistance on the basis of high mechanical properties, meeting the multi-performance requirements of high-end application scenarios.

[0025] In this application, the reinforced short fiber (Taishan glass short fiber) is modified with γ-aminopropyltriethoxysilane coupling agent to form a chemical bond with the amide bond of PPA, thereby improving the interfacial bonding force with the matrix and constructing a mechanical support framework; the conductive short fiber (metal-coated antistatic short fiber) is subjected to plasma etching treatment, which not only strengthens the interfacial bonding, but also constructs a continuous conductive network through an appropriate aspect ratio, thereby achieving the function of conductive and anti-electromagnetic interference. The 1:2 mass ratio of the two balances the mechanical reinforcement and conductive function requirements.

[0026] In one embodiment, the lubricant (fatty acid esters) reduces intermolecular friction and optimizes processing fluidity; the compounded antioxidant (1098 and phosphite esters in a 2:1 ratio) inhibits high-temperature processing oxidative degradation; and the nucleating agent (adipic acid-1,6-bis(2-benzoylhydrazine)) refines the crystalline particles, further improving the material's heat resistance and dimensional stability. The three work synergistically to ensure the material's stable performance throughout its entire lifecycle.

[0027] In one embodiment, the reinforced short fibers have a diameter of 10-20 μm and a length of 3-5 mm. The γ-aminopropyltriethoxysilane coupling agent coated on the surface forms a chemical bond with the amide bonds of PPA, significantly improving the interfacial adhesion. The conductive short fibers have a diameter of 5-15 μm and a length of 1-3 mm. The increased surface roughness and active sites from plasma etching promote effective bonding between the conductive short fibers, constructing a continuous and efficient conductive network, resulting in a material volume resistivity ≤10. 6 Ω·cm, electromagnetic shielding effectiveness ≥20dB, meeting the requirements for conductive electromagnetic interference resistance in the planned mass production.

[0028] In one embodiment, the terminal amino content of the polyphthalamide is 30-50 mmol / kg, which forms interfacial hydrogen bond clusters with the hydroxyl and carboxyl groups in the functional short fiber combination. The total interaction energy is 20-30 kJ / mol. This hydrogen bonding can ensure the interfacial bonding force between the PPA matrix and the short fiber, while also retaining a certain degree of flexibility at the interface, reducing stress concentration, and ensuring stable mechanical properties. This results in a material with a bending strength ≥160 MPa, notched impact strength ≥50 J / m, and tensile strength ≥145 MPa, meeting the mechanical property requirements for the planned mass production.

[0029] In one preferred embodiment, the polyphthalamide material comprises the following components in parts by weight: 50 parts polyphthalamide (Zhejiang Yili SH120A); 5 parts nano zinc borate (particle size 50-100nm); 15 parts 6700 halogenated flame retardant (brominated epoxy resin derivative); 30 parts functional short fiber combination (10 parts reinforced short fiber, 20 parts conductive short fiber); 1 part additive (0.6 parts lubricant, 0.2 parts antioxidant, 0.2 parts nucleating agent); and 1 part black masterbatch (carbon black content 30%).

[0030] The preferred formulation has the following performance indicators: density 1.478-1.536 g / cm³, melt index 22-25 g / 10min (290℃, 2.16 kg), flexural strength 165-175 MPa, notched impact strength 55-60 J / m, tensile strength 150-160 MPa, heat deflection temperature (0.45 MPa) 255-260℃, heat deflection temperature (1.82 MPa) 228-230℃, and volume resistivity 5×10⁻⁶. 5 Up to 1×10 6 Ω·cm, flame retardant performance reaches UL94 V0 level (3.2mm), electromagnetic shielding effectiveness ≥22dB, moisture content ≤0.1%.

[0031] For example, the polyphthalamide material also includes 1 part of a colorant, which is a black masterbatch with a carbon black content of 30%.

[0032] The above-mentioned polyphthalamide material has a mass ratio of 45-55 parts of polyphthalamide as the matrix. By adding 4-6 parts of inorganic synergistic flame retardant (such as zinc borate) and 12-18 parts of halogenated flame retardant (such as brominated flame retardant), the material can achieve UL94 V0 flame retardant performance through the synergistic mechanism of gas phase flame retardancy and condensed phase flame retardancy. This solves the problem of insufficient function or deterioration of mechanical properties caused by the addition of a single flame retardant. By adding 28-32 parts of a functional short fiber combination, which consists of reinforcing short fibers and conductive short fibers, with a mass ratio of reinforcing short fibers to conductive short fibers of "8-12": "18-22", the reinforcing short fibers (such as glass short fibers (Taishan short fibers)) significantly improve the bending strength and tensile strength of the material through physical reinforcement; the conductive short fibers (such as metal-coated short fibers with antistatic function) achieve conductivity by constructing a continuous conductive network, and at the same time, this network can effectively shield electromagnetic interference signals, thus solving the contradiction in the prior art of simultaneously achieving conductive modification and flame retardancy and mechanical properties.

[0033] In this application, polyphthalamide (PPA), as a semi-aromatic polyamide, possesses high heat resistance and low water absorption due to its aromatic ring structure in its molecular chain. Its inherent thermal properties—melting point 290-310℃ and decomposition temperature ≥400℃—provide a stable matrix for multi-performance modification, avoiding thermal degradation issues during high-temperature processing. A halogenated flame retardant (6700 halogenated flame retardant, a brominated epoxy resin derivative) and an inorganic synergistic flame retardant (nano-zinc borate) are compounded at a 3:1 mass ratio, exhibiting high synergistic efficiency. Through the synergistic effect of gas-phase flame retardancy (bromine free radicals capturing combustion-active substances) and condensed-phase flame retardancy (zinc borate decomposition forming a dense, heat-insulating char layer), only 16-24 parts of flame retardant are needed to achieve UL94 V0 flame retardant performance without compromising the heat-resistant structure of the matrix. Simultaneously, the excellent char-forming properties of PPA enhance the flame retardant effect, avoiding the damage to mechanical properties caused by excessive flame retardant. The reinforced short fiber (Taishan glass short fiber) is modified with γ-aminopropyltriethoxysilane coupling agent to form chemical bonds with the amide bonds of PPA, enhancing the interfacial bonding force with the matrix and constructing a mechanical support framework. The conductive short fiber (metal-coated antistatic short fiber) is plasma-etched to strengthen the interfacial bonding and construct a continuous conductive network through an appropriate aspect ratio, achieving conductive and anti-electromagnetic interference functions. The 1:2 mass ratio of the two balances the mechanical reinforcement and conductivity requirements, and is compatible with existing short fiber feeding equipment without the need to adjust the feeding ratio. The lubricant (fatty acid esters) reduces intermolecular friction and optimizes processing flowability; the compound antioxidant (1098 and phosphite esters in a 2:1 ratio) inhibits high-temperature processing oxidative degradation; the nucleating agent (adipic acid-1,6-bis(2-benzoylhydrazine)) refines the crystalline particles, further improving the material's heat resistance and dimensional stability. The three work synergistically to ensure the material's stable performance throughout its entire life cycle.

[0034] Secondly, this application provides a method for preparing the polyphthalamide material as described in any of the above embodiments, characterized in that the preparation method includes the following steps: Polyphthalamide resin, lubricant, antioxidant, and nucleating agent are mixed in a high-speed mixer at a speed of 800-1200 r / min for 5-8 min to obtain a premix. The premixed material is added to the main feed inlet of the twin-screw extruder at a feed rate of 200 kg / h. The inorganic synergistic flame retardant and halogenated fire retardant are added through the side feed inlet in the fifth section. When the melt pressure reaches 15-20 MPa, the functional short fiber combination side feed is activated, with the short fiber feed rate to main feed ratio at 1:3.5. The temperatures of each section of the twin-screw extruder from the feed inlet to the die head are as follows: Section 1 310-320℃, Section 2 300-310℃, Section 3 300-310℃. 0℃, fourth stage 290-300℃, fifth stage 280-290℃, sixth stage 270-280℃, seventh stage 260-270℃, eighth stage 250-260℃, ninth stage 240-250℃, die head temperature 300-320℃; screw speed 300-320r / min, vacuum degree -0.09~-0.095MPa, melt pressure controlled at 15-25MPa, and actual melt temperature 285-290℃.

[0035] In one embodiment, the method for preparing the polyphthalamide material includes the following steps: (1) Raw material pretreatment: The polyphthalamide resin was pre-dried by hot air at 120-130℃ for 3-4 hours, and then vacuum dried at 120℃ for 2-3 hours. The moisture content of the dried material was ≤0.1% (tested by Mettler DL32 moisture meter, which met the predetermined offline testing standard); The reinforced short fiber was placed in a 2% (w / w) aqueous solution of γ-aminopropyltriethoxysilane (pH adjusted to 3.5-4.5 with acetic acid), stirred at 70℃ for 45 minutes, filtered, and dried at 120℃ for 3 hours; The conductive short fiber was subjected to plasma etching treatment with an etching power of 120W for 8 minutes. The etching gas was a mixture of argon and oxygen (volume ratio 3:1), the etching vacuum was 10-30Pa, the argon flow rate was 20sccm, and the oxygen flow rate was 7sccm; to ensure the surface modification effect of the short fiber and improve the interfacial bonding force with the PPA matrix.

[0036] (2) Premixing: Add the pretreated polyphthalamide resin, lubricant, antioxidant, nucleating agent and colorant to a high-speed mixer (model: SHR-1000A), with a speed of 800-1200 r / min, a time of 5-8 min, and a discharge temperature of ≤50℃ to obtain a premixed material; ensure that the components are initially mixed evenly to avoid component agglomeration during subsequent melt blending.

[0037] (3) Segmented melt blending: The premixed material is added to the main feed port of the twin-screw extruder (model: TE-75, length-to-diameter ratio 40:1) at a feed rate of 200 kg / h; the inorganic synergistic flame retardant and halogenated fire retardant are added in the fifth segment through the side feed port. When the melt pressure reaches 15-20 MPa, the functional short fiber combination side feed is turned on, and the short fiber feeding rate is 1:3.5 to the main feed rate; the temperatures of each segment of the twin-screw extruder from the feed port to the die head are as follows: first segment 310-320℃, second segment 300-310℃, third segment 300-310℃. Temperature ranges are as follows: ℃, fourth section 290-300℃, fifth section 280-290℃, sixth section 270-280℃, seventh section 260-270℃, eighth section 250-260℃, ninth section 240-250℃, die head temperature 300-320℃; screw speed 300-320r / min, vacuum degree -0.09~-0.095MPa, melt pressure controlled at 15-25MPa, and actual melt temperature 285-290℃; avoid local overheating leading to material degradation, and ensure that all components are fully melted, blended, and evenly dispersed.

[0038] (4) Granulation and post-processing: After the extrudate is cooled in a water cooling tank (water temperature 25-30℃, cooling length 3m), it is granulated in a pelletizer (cutter speed 800-1000r / min) with a particle length of 2-3mm and a roundness of ≥95%. A 20-mesh vibrating screen (screen aperture 0.85mm) is used to screen the particles to remove long strips and broken pieces with a screening efficiency of ≥98%. The sieved particles are stored in a drying silo (temperature 80-90℃, relative humidity ≤30%) for a storage period of ≤72h to obtain polyphthalamide material.

[0039] The short fiber pretreatment process described in this application solves the problem of weak interfacial bonding between traditional short fibers and the PPA matrix, improving the stability of mechanical properties, while eliminating the need for additional pretreatment equipment. The temperature profile, screw speed, vacuum degree, and other parameters of the twin-screw extruder are reused from existing PA9T mass production parameters, precisely adapting to the thermal properties of PPA (melting point 290~310℃), avoiding high-temperature degradation and insufficient melting at low temperatures. The segmented side-feeding design, pelletizing, and screening processes are all reused from existing processes, ensuring uniform dispersion of all components. In particular, the flame retardant and short fibers are added within the appropriate temperature range to prevent premature decomposition or agglomeration, while simultaneously improving production efficiency and reducing production costs. Thirdly, the polyphthalamide material provided in this application can be applied to electronic devices and automotive parts. The electronic devices include core connectors and housings of personal computers, digital cameras, and mobile phones; the automotive parts include high-temperature components around the engine, fuel line connectors, and key components of the ABS system. This material, with its high temperature resistance, flame retardancy, electrical conductivity, electromagnetic interference resistance, and stable mechanical properties, and its compatibility with existing PA9T materials, can replace traditional metals or single-performance plastics, meeting the stringent requirements of high-end applications.

[0040] To further illustrate the polyphthalamide material and its preparation method of this application, specific embodiments are given below to continue the explanation of this application.

[0041] Example 1 The formulation of the polyphthalamide material includes the following components in parts by weight: Polyphthalamide (Zhejiang Yili SH120A, purchased from Zhejiang Yili Technology Group Co., Ltd., model: polyphthalamide SH120A): 50 parts; Lubricant 350 (fatty acid ester, supplier: Guangzhou Rongda Chemical Co., Ltd.): 0.6 parts; Antioxidant (1098 and phosphites in a 2:1 ratio, 1098 purchased from Dongguan Munan Chemical New Materials Co., Ltd.): 0.2 parts; Nucleating agent 360 (adipic acid-1,6-bis(2-benzoylhydrazide), purchased from Guangzhou Rongda Chemical Co., Ltd., specification: wax powder RBW 360 P): 0.2 parts; Nano zinc borate (particle size 50-100nm): 5 parts; 6700 Halogenated Fire Retardant (Brominated Epoxy Resin Derivative, purchased from Shandong Mait New Material Technology Co., Ltd., model: Brominated Polystyrene 6700): 15 parts; Black masterbatch (30% carbon black content): 1 part; Taishan short fiber (glass short fiber, diameter 10-20μm, length 3-5mm): 10 parts; Antistatic staple fiber (metal-coated staple fiber, diameter 5-15μm, length 1-3mm): 20 parts; Total weight: 100 portions.

[0042] The preparation process is as follows: 1. Raw material pretreatment: The polyphthalamide resin was pre-dried with hot air at 120-130℃ for 3.5h, and then vacuum dried at 120℃ for 2.5h. The moisture content was measured using a Mettler DL32 moisture analyzer and was 0.07% (meeting the predetermined standard of ≤0.1%). The Taishan short fiber was placed in a 2% (w / w) aqueous solution of γ-aminopropyltriethoxysilane (pH 3.5-4.5), stirred at 70℃ for 45min, filtered, and dried at 120℃ for 3h. The antistatic short fiber was subjected to plasma etching treatment with an etching power of 120W, a time of 8min, an argon flow rate of 20sccm, an oxygen flow rate of 7sccm, and a vacuum degree of 20Pa.

[0043] 2. Premixing: Add the pretreated PPA resin, lubricant 350, compound antioxidant, nucleating agent 360, and black masterbatch to a high-speed mixer (model: SHR-1000A), with a speed of 1000 r / min, a mixing time of 5 min, and a discharge temperature of 48℃ to obtain the premixed material.

[0044] 3. Segmented melt blending: Add the premixed material to the main feed port of a twin-screw extruder (model: TE-75, L / D ratio 40:1) at a feed rate of 200 kg / h; add nano-zinc borate and 6700 halogenated flame retardant via the fifth-stage side feed. When the melt pressure reaches 18 MPa, open side feed 2 (30 parts of functional short fiber combination) at a feed rate of 60 kg / h; extruder section temperatures: first section 310-320℃, second section 300-310℃. The temperature ranges as follows: ℃, third stage 300-310℃, fourth stage 290-300℃, fifth stage 280-290℃, sixth stage 270-280℃, seventh stage 260-270℃, eighth stage 250-260℃, ninth stage 240-250℃, die head temperature 300-320℃; screw speed 310r / min, vacuum degree -0.092MPa, melt pressure 22MPa, melt temperature 288℃. After extrusion stabilizes, material collection begins.

[0045] 4. Granulation and post-processing: After the extrudate is cooled in a water cooling tank (water temperature 28℃, cooling length 3m), it enters a pelletizer (speed 900r / min) and is cut into pellets with a length of 2.5mm. The pellets are screened by a 20-mesh vibrating screen to remove 3 long strips (meeting the standard of ≤5 strips / 10kg). The screened pellets are stored in an 80℃ drying silo for later use.

[0046] Example 2 Polyphthalamide (Zhejiang Yili SH120A): 45 parts; Lubricant 350: 0.5 parts; Compound antioxidant: 0.225 parts (0.15 parts 1098 + 0.075 parts phosphites); Nucleating agent 360: 0.15 parts; Nano zinc borate: 4 parts; 6700 Halogenated Fire Retardant: 12 parts; Black masterbatch (30% carbon black content): 1 part; Taishan staple fiber: 8 parts; Antistatic staple fiber: 22 parts; Total weight: 100 portions.

[0047] The preparation process is the same as in Example 1.

[0048] Example 3 Formula composition (parts by weight): Polyphthalamide (Zhejiang Yili SH120A): 55 parts; Lubricant 350: 0.7 parts; Compound antioxidant: 0.375 parts (0.25 parts 1098 + 0.125 parts phosphite); Nucleating agent 360: 0.25 parts; Nano zinc borate: 6 parts; 6700 Halogenated Fire Retardant: 18 parts; Black masterbatch (30% carbon black content): 1 part; Taishan staple fiber: 12 parts; Antistatic staple fiber: 18 parts; Total weight: 100 portions.

[0049] The preparation process is the same as in Example 1.

[0050] Comparative Example 1: Polyphthalamide (Zhejiang Yili SH120A): 60 parts; Lubricant 350: 0.6 parts; Antioxidant 1098: 0.2 parts; Brominated flame retardant: 15 parts; Ordinary glass short fiber: 20 parts; Total weight: 100 portions.

[0051] Preparation process: conventional twin-screw extruder for blending and granulation, extruder homogenization temperature of 320℃, no surface modification of short fibers, no mass production process parameters, and the remaining steps are the same as in Example 1.

[0052] The results of tests conducted on Examples 1 to 3 and the comparative examples are shown in Table 1. Table 1 Test results of each embodiment and comparative example As can be seen from the above embodiments: Mechanical properties: The bending strength, tensile strength, and notched impact strength of Examples 1-3 were significantly higher than those of Comparative Example 1, and all met the qualified standards. Among them, the bending strength of Example 1 was increased by 27.4% and the notched impact strength was increased by 52.6% compared with the Comparative Example, indicating that the interfacial bonding force between the short fiber and the PPA matrix was strengthened through short fiber surface modification and formulation optimization, which effectively improved the mechanical properties of the material.

[0053] Flame retardant performance: Examples 1-3 all achieved UL94 V0 level flame retardant performance and met the predetermined qualification standard, while Comparative Example 1 was only V1 level. This indicates that the 3:1 synergistic flame retardant system of nano zinc borate and 6700 halogenated fire retardant is more efficient and adaptable to the char formation characteristics of PPA. Excellent flame retardant effect can be achieved without adding excessive flame retardant.

[0054] Electrical conductivity and electromagnetic interference immunity: The volume resistivity of Examples 1-3 is ≤10. 6 Ω·cm, electromagnetic shielding effectiveness ≥20dB, all meet the predetermined qualification standards, have good anti-static and anti-electromagnetic interference capabilities, and Comparative Example 1 has no conductive function, highlighting the design advantages of functional short fiber combination (reinforced type + conductive type) and surface modification process. Processing and heat resistance: The melt index of Examples 1-3 is 20.8-24.7 g / 10 min, with excellent processing fluidity. The heat distortion temperature and moisture content both meet the predetermined qualified standards, indicating that the additive system in the formula and the processing technology are adapted to the thermal performance characteristics of PPA, ensuring processing stability and heat resistance. At the same time, the moisture content is controlled to meet the standards, avoiding the impact of moisture absorption on mechanical properties.

[0055] The polyphthalamide material provided in this application has the advantages of fire resistance, electrical conductivity, high temperature resistance, flame retardancy, electrical conductivity, and resistance to electromagnetic interference.

[0056] It should be noted that current research in the field of PPA modification generally faces three major technical bottlenecks: First, "functional singularity," with most studies focusing only on single-performance modification, failing to achieve the integration of flame retardancy, conductivity, and high temperature resistance; second, "multiple performance superposition leading to mechanical degradation," where the addition of flame retardants and conductive fillers simultaneously results in poor interfacial compatibility and a significant decrease in mechanical properties; and third, "mismatch between processing and matrix thermal properties," where existing processes easily lead to PPA degradation and poor processing stability. The performance of traditional PPA modification systems is disconnected from mass production requirements, failing to meet specific indicators such as a density of 1.478-1.536 g / cm³ and a moisture content ≤0.1%. This application precisely addresses the bottlenecks mentioned above in the literature. Through synergistic flame retardant system, optimization of functional short fibers, adaptation of additives, and process adjustment, it achieves integrated high temperature resistance, flame retardancy, conductivity, electromagnetic interference resistance, and stable mechanical properties. At the same time, it completely reuses existing PA9T mass production equipment and processes without requiring equipment modification. It solves the technical problem of not being able to balance multiple properties with mass production adaptability in the prior art, fills the gap in the prior art, and its solution to the technical problem is clearly targeted and groundbreaking, which would not be easily thought of by those who are not skilled in the art.

[0057] The modification strategies proposed in this application are as follows: First, an innovation in the flame retardant system. Existing literature typically uses a 5:1 to 4:1 ratio of halogenated flame retardants to inorganic synergistic flame retardants, requiring a large amount of flame retardant to achieve V0 flame retardancy. This application innovatively uses a 3:1 mass ratio (reusing the flame retardant formulation from PA9T mass production), combined with the char-forming characteristics of PPA itself, requiring only 16-24 parts of total flame retardant to achieve V0 flame retardancy, avoiding the damage to mechanical properties caused by excessive flame retardant, thus breaking through the conventional understanding of existing literature. Second, an innovation in short fiber interface modification. Existing literature often uses a single method for short fiber modification, resulting in weak interfacial bonding and discontinuous conductive network construction. This application adopts a "differentiated pretreatment" strategy (reusing existing short fiber modification processes), coating reinforcing short fiber coupling agents and plasma etching of conductive short fibers, combined with hydrogen bonding, to both strengthen interfacial bonding and construct a continuous conductive network, reducing the volume resistivity to 10. 6 Below Ω·cm, it breaks through the technical bottleneck of existing literature. Thirdly, the processing technology is innovative. Existing literature mostly adopts uniform high-temperature processing, which easily leads to PPA degradation. However, this application reuses the gradient temperature of the predetermined PA9T (first stage 310-320℃, second stage 300-310℃, third stage 300-310℃, fourth stage 290-300℃, fifth stage 280-290℃, sixth stage 270-280℃, seventh stage 260-270℃, eighth stage 250-260℃, ninth stage 240-250℃, die head temperature 300-320℃), which is adapted to the thermal properties of PPA melting point of 290~310℃. It ensures full melting and avoids high-temperature degradation. At the same time, it is perfectly compatible with existing mass production equipment without the need for equipment modification, thus solving the problem of the disconnect between existing processes and mass production.

[0058] The technical features of the embodiments described above can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification. It should be noted that the terms "in one embodiment," "for example," and "again," etc., in this application are intended to illustrate the application and not to limit it. The embodiments described above only illustrate several implementations of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. A polyphthalamide material, characterized in that, The components include the following parts by weight: 45-55 parts of polyphthalamide; 4-6 parts of inorganic synergistic flame retardant; 12-18 parts of halogenated fire retardant; Functional short fiber blend of 28-32 parts; Additives: 0.9-1.1 parts; The functional short fiber combination consists of reinforcing short fibers and conductive short fibers, wherein the mass ratio of reinforcing short fibers to conductive short fibers is "8-12":"18-22".

2. The polyphthalamide material according to claim 1, characterized in that, The 0.9 to 1.1 parts of additives include 0.5 to 0.7 parts of lubricant, 0.15 to 0.25 parts of antioxidant, and 0.15 to 0.25 parts of nucleating agent.

3. The polyphthalamide material according to claim 2, characterized in that, The lubricant is a fatty acid ester or a polyolefin wax lubricant; And / or, the antioxidant is a compound of primary antioxidant 1098 and phosphite auxiliary antioxidant in a mass ratio of 2:1; And / or, the nucleating agent is adipic acid-1,6-bis(2-benzoylhydrazine), and the difference between the nucleating agent and the Hansen solubility parameter of the polyphthalamide matrix is ​​≤1.5 (J / cm³)¹ / ².

4. The polyphthalamide material according to claim 2, characterized in that, The inorganic synergistic flame retardant includes at least one of zinc borate, sodium antimonate, and magnesium hydroxide; preferably, the inorganic synergistic flame retardant is nano zinc borate with a particle size of 50-100 nm. And / or, the halogenated fire retardant is a brominated flame retardant or a chlorinated flame retardant; preferably, the halogenated fire retardant is a brominated epoxy resin derivative with a number average molecular weight of 3000-5000 g / mol and a bromine content of 58%-62%; And / or, the mass ratio of halogenated fire retardant to inorganic synergistic flame retardant is 3:

1.

5. The polyphthalamide material according to claim 2, characterized in that, The reinforced short fiber includes at least one of glass short fiber and basalt short fiber; the surface of the reinforced short fiber is coated with γ-aminopropyltriethoxysilane coupling agent, and the coating amount is 0.5%-1.0% of the short fiber mass; And / or, the conductive short fiber includes at least one of carbon fiber and metal-coated short fiber; the surface of the conductive short fiber is subjected to plasma etching treatment with an etching depth of 50-200 nm; And / or, the reinforced short fiber is Taishan short fiber, and the conductive short fiber is antistatic short fiber; Preferably, the reinforced short fiber is a glass short fiber (Taishan short fiber) with a diameter of 10-20 μm and a length of 3-5 mm, and its surface is coated with γ-aminopropyltriethoxysilane coupling agent, with a coating amount of 0.5%-1.0% of the short fiber mass; the conductive short fiber is a metal-coated antistatic short fiber with a diameter of 5-15 μm and a length of 1-3 mm, and its surface is treated with plasma etching to an etching depth of 50-200 nm.

6. The polyphthalamide material according to claim 1, characterized in that, The polyphthalamide has a mass fraction of 50 parts; the inorganic synergistic flame retardant has a mass fraction of 5 parts; the halogenated fire retardant has a mass fraction of 15 parts; and the mass ratio of the reinforced short fiber to the conductive short fiber is 1:

2. And / or, the performance indicators of the polyphthalamide material are as follows: density 1.478-1.536 g / cm³, melt flow index 20-25 g / 10 min, flexural strength ≥160 MPa, notched impact strength ≥50 J / m, tensile strength ≥145 MPa, heat distortion temperature 250-260℃ at 0.45 MPa, heat distortion temperature 220-230℃ at 1.82 MPa, flame retardancy reaching UL94 V0 level (3.2 mm), and volume resistivity ≤10 Ω·cm. 6 Ω·cm, electromagnetic shielding effectiveness ≥20dB in the 8-18GHz frequency band, and moisture content ≤0.1%.

7. The polyphthalamide material according to claim 2, characterized in that, The conductive short fiber has a diameter of 5-15μm and a length of 1-3mm; And / or, the diameter of the reinforced short fiber is 10-20 μm and the length is 3-5 mm.

8. The polyphthalamide material according to claim 2, characterized in that, The content of terminal amino groups in the polyphthalamide is 30-50 mmol / kg, and it forms interfacial hydrogen bond clusters with hydroxyl and carboxyl groups in the functional short fiber combination, with a total interaction energy of 20-30 kJ / mol. And / or, the polyphthalamide material also includes 1 part of a colorant, said colorant being a black masterbatch with a carbon black content of 30%.

9. The method for preparing the polyphthalamide material according to any one of claims 2-8, characterized in that, The preparation method includes the following steps: Polyphthalamide resin, lubricant, antioxidant, and nucleating agent are mixed in a high-speed mixer at a speed of 800-1200 r / min for 5-8 min to obtain a premix. The premixed material is added to the main feed inlet of the twin-screw extruder at a feed rate of 200 kg / h. The inorganic synergistic flame retardant and halogenated fire retardant are added through the side feed inlet in the fifth section. When the melt pressure reaches 15-20 MPa, the functional short fiber combination side feed is activated, with the short fiber feed rate to main feed ratio at 1:3.

5. The temperatures of each section of the twin-screw extruder from the feed inlet to the die head are as follows: Section 1 310-320℃, Section 2 300-310℃, Section 3 300-310℃. 0℃, fourth stage 290-300℃, fifth stage 280-290℃, sixth stage 270-280℃, seventh stage 260-270℃, eighth stage 250-260℃, ninth stage 240-250℃, die head temperature 300-320℃; screw speed 300-320r / min, vacuum degree -0.09~-0.095MPa, melt pressure controlled at 15-25MPa, and actual melt temperature 285-290℃.

10. The application of the polyphthalamide material according to any one of claims 1-8, or the polyphthalamide material prepared by the preparation method according to claim 9, in electronic devices, wherein the electronic devices include personal computers, digital cameras, and mobile phones.

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