A high-performance flame-retardant reinforced PPA composite material and its production method

Abstract

The invention discloses a high-performance flame-retardant reinforced PPA composite material and a production method thereof, which belongs to the field of plastic technology, and comprises the following steps: using hydroxyethyl acrylate as a monomer, modifying the PPA resin under the action of an initiator; premixing the main dispersant stearic acid with the surface-treated filler glass fiber and the flame-retardant masterbatch, so that the stearic acid is fully adsorbed on the filler surface; drying the graft copolymerized modified resin; first mixing the resin with the auxiliary dispersant polyethylene glycol, then adding the mixed filler wrapped by stearic acid for further mixing, and finally adding a composite antioxidant and other additives; and finally extruding. The present invention realizes high-filled glass fiber reinforcement while overcoming the problems of decreased flame retardancy, poor dispersibility and weak interface bonding caused by the addition of glass fiber, and through the optimization of raw material components and preparation processes, the material reaches the UL94V0 flame retardant grade and the comprehensive performance reaches the best balance.

Description

Technical Field

[0001] The present invention mainly relates to the field of plastic technology, and specifically relates to a high-performance flame-retardant reinforced PPA composite material and a production method thereof. Background Art

[0002] In the modern industrial field, polyphthalamide (PPA) occupies an important position in many key industries such as automobile manufacturing, electronic and electrical production, and aerospace due to its excellent mechanical strength, good thermal stability, and excellent chemical resistance. In the process of pursuing high-strength applications, the introduction of reinforcing fillers such as glass fiber and carbon fiber has become a common strategy to improve the performance of PPA. Among them, glass fiber is highly favored because of its cost advantage and significant reinforcement effect. High-filling glass fiber can effectively enhance the strength and dimensional stability of PPA materials, making it sufficient to meet application scenarios with extremely stringent requirements on mechanical properties, such as automotive precision parts and core structural parts of electronic appliances.

[0003] However, with the industry's continuous increase in requirements for the comprehensive performance of materials, the traditional glass fiber reinforced PPA method has gradually exposed a series of thorny problems. In terms of flame retardant properties, although PPA itself has a certain flame retardant foundation, its native flame retardant performance is far from meeting the strict flame retardant grade requirement of UL94V0 in application areas with extremely high fire safety standards, such as key core components of electronic and electrical equipment and specific high-risk components in the engine compartment of automobiles. When high-filled glass fiber reinforcement is used, although the material strength is improved, its flame retardant performance suffers a serious negative impact. This is mainly attributed to the fact that the high filling amount of glass fiber changes the microstructure and heat conduction path inside the material. During the combustion process, it may destroy the continuity of the barrier layer formed by the flame retardant, or its high thermal conductivity accelerates heat transfer, making the flame easier to spread, and ultimately resulting in a significant reduction in the overall flame retardant effect of the material.

[0004] Existing flame retardant technology also has many limitations. Although traditional halogen flame retardants have relatively high flame retardant efficiency, they release a large amount of toxic hydrogen halide gas during combustion, posing a serious threat to the ecological environment and human health. Under the current situation of increasingly stringent environmental protection regulations, its application has been greatly restricted. Although phosphorus-based flame retardants can promote the carbonization of the material surface to form a solid flame retardant layer, it is difficult to make PPA reach the UL94V0 flame retardant grade when used alone, and it may have an adverse effect on the mechanical properties of the material. Although nitrogen-based flame retardants such as melamine cyanurate (MCA) have the advantages of low toxicity and low smoke, their flame retardant performance is relatively limited, and it is difficult to independently meet the flame retardant requirements in high-demand application scenarios.

[0005] In addition, the dispersion of glass fiber in the PPA matrix and the influence of the interface bonding force on the material properties cannot be ignored. If the glass fiber is unevenly dispersed, stress concentration points will be formed, which will not only weaken the uniformity of the mechanical properties of the material, but also become a channel for flame propagation, thereby reducing the flame retardant properties of the material. When the interface bonding is poor, the glass fiber and the matrix are prone to interface separation during the stress process, which makes the glass fiber unable to fully exert its reinforcing effect, limiting the improvement of the mechanical properties of the material, and also has a negative impact on the flame retardant effect during combustion.

[0006] In view of the adverse effects of high-filled glass fiber on flame retardancy, dispersibility and interfacial bonding, as well as the environmental and performance defects of traditional flame retardants, it has become an urgent task to develop a PPA composite material that can take into account high strength, high flame retardancy, good dispersibility and strong interfacial bonding. It is of vital importance to promote the development of related industries. Summary of the invention

[0007] One of the purposes of the present invention is to provide a high-performance flame-retardant reinforced PPA composite material and a production method thereof, which can achieve high-filled glass fiber reinforcement while overcoming the problems of decreased flame retardancy, poor dispersibility and weak interface bonding caused by the addition of glass fiber, and through the optimization of raw material components and a unique preparation process, the material can reach the UL94V0 flame retardant grade and achieve the best balance of comprehensive performance.

[0008] The technical solution adopted by the present invention to solve the above technical problems is:

[0009] In a first aspect, the present invention provides a method for producing a high-performance flame-retardant reinforced PPA composite material, comprising the following steps:

[0010] (1) PPA graft copolymerization modification: Using hydroxyethyl acrylate as a monomer, the PPA resin is modified under the action of an initiator to obtain a graft copolymerized PPA resin. During the reaction, the double bonds of hydroxyethyl acrylate are opened under the action of the initiator, and a free radical polymerization reaction occurs with the PPA molecular chain, and the grafted PPA molecular chain grows. The grafted PPA molecular chain introduces polar side chains and active groups, which increases flexibility.

[0011] Polar side chains and active groups can form hydrogen bonds or other intermolecular forces with the components in the flame retardant masterbatch, enhance the compatibility with the flame retardant masterbatch, and prevent the flame retardant from agglomerating; at the same time, when mixed with glass fiber, it can better wrap around the surface of the glass fiber, improve its dispersion state in the PPA matrix, reduce stress concentration points, and improve the comprehensive performance of the composite material.

[0012] (2) Filler premixing: Premix the main dispersant stearic acid with the surface-treated filler glass fiber and flame retardant masterbatch so that the stearic acid is fully adsorbed on the filler surface to form a uniform "coating layer".

[0013] Stearic acid molecules have hydrophilic carboxyl groups (-COOH) and hydrophobic long carbon chains. When pre-mixed with glass fiber and flame retardant masterbatch, the carboxyl groups of stearic acid can undergo physical adsorption or weak chemical reactions with the hydroxyl groups (-OH) on the surface of the glass fiber or some active groups on the surface of the flame retardant masterbatch. Its long carbon chain extends outward to form a "coating layer" on the surface of the filler. This coating layer reduces the mutual attraction between fillers, making them easier to disperse in the PPA matrix during the subsequent mixing process.

[0014] At the same time, when the PPA resin comes into contact with the filler coated with stearic acid, the long carbon chain of stearic acid can be entangled with the PPA molecular chain, making it easier for the filler to integrate into the PPA matrix and reducing interface defects.

[0015] (3) Drying treatment: The PPA resin modified by graft copolymerization is dried to make its moisture content lower than 0.03% to prevent moisture from affecting the material properties during processing.

[0016] (4) Mixing process: firstly, the dried graft copolymer modified PPA resin is mixed with the auxiliary dispersant polyethylene glycol, then the mixed filler wrapped by stearic acid is added for further mixing, and finally, the composite antioxidant and other additives are added.

[0017] The auxiliary dispersant polyethylene glycol has a suitable molecular weight (molecular weight 500~600), and its molecular chain can extend on the filler surface, preventing filler agglomeration through steric hindrance effect, and improving the interfacial compatibility between the filler and the PPA matrix, so that fillers such as glass fibers are evenly dispersed in the PPA matrix, thereby improving the mechanical properties and flame retardant properties of the material.

[0018] (5) Extrusion molding: The mixed material is conveyed to a twin-screw extruder for extrusion.

[0019] In a method that can be implemented in the first aspect, the dried PPA resin and the toluene solution are added in proportion in sequence, and stirring is started to allow the PPA to completely dissolve in the toluene solution to form a homogeneous solution. Subsequently, a hydroxyethyl acrylate solution containing an initiator is slowly added dropwise under nitrogen protection, and the addition time is controlled within 30 to 45 minutes to ensure that the initiator is evenly dispersed in the reaction system to initiate the grafting reaction.

[0020] After the addition is complete, the temperature is raised to the set reaction temperature and maintained at a constant temperature, and the reaction is stirred continuously. During the reaction, the temperature of the reaction system is maintained stable to prevent the reaction rate and grafting effect from being affected by temperature fluctuations; samples are taken every 1 to 1.5 hours, and infrared spectroscopy (FT-IR) or gel permeation chromatography (GPC) is used to analyze the grafting rate and molecular chain structure changes to ensure that the grafting reaction proceeds as expected and maintain the grafting rate stable at 10% to 15%.

[0021] Furthermore, the PPA resin uses a relative molecular mass of 25000-35000, which has a moderate melt flow rate (such as 10-20g / 10min at 230°C and 2.16kg), which can ensure good fluidity and formability during the grafting reaction and subsequent processing, while ensuring that the material has a certain mechanical strength foundation.

[0022] And / or, the reaction temperature of the grafting reaction is 85-95° C., and the reaction time is 5-7 hours.

[0023] The above temperature range is determined based on the thermal stability of PPA and the reaction activity of hydroxyethyl acrylate and initiator. If the temperature is too low, the reaction rate is too slow and the grafting efficiency is low; if the temperature is too high, the PPA molecular chain is prone to degradation or excessive cross-linking, which will damage the material properties. This range can ensure that the reaction proceeds smoothly and efficiently, promote the growth of the grafted chain and maintain the stability of the PPA main structure. Sufficient reaction time can ensure that hydroxyethyl acrylate fully reacts with the PPA molecular chain to achieve the expected grafting rate.

[0024] And / or, the mass ratio of the PPA resin to hydroxyethyl acrylate is 1:9 to 1:8; this ratio range can ensure effective grafting while avoiding excessive changes in the original properties of PPA due to excessive hydroxyethyl acrylate or poor grafting effect due to too little hydroxyethyl acrylate, so that the grafted PPA has good compatibility and maintains its own performance.

[0025] And / or, the initiator is benzoyl peroxide, and its dosage is 0.6% to 0.9% of the mass of the PPA resin. Within this dosage range, the grafting reaction can be effectively initiated, and the problems of side reactions caused by excessive initiator or low grafting rate and incomplete reaction caused by insufficient initiator can be prevented, thereby ensuring that the grafting process is efficient and stable.

[0026] In a manner that can be implemented in the first aspect, the method further includes:

[0027] Dispersant pretreatment: the composite dispersant includes a main dispersant, stearic acid, and an auxiliary dispersant, polyethylene glycol, and the main dispersant, stearic acid, and the auxiliary dispersant, polyethylene glycol, are pretreated;

[0028] The main dispersant stearic acid and a small amount of ethanol are mixed at a mass ratio of 1:2.5-1:3 to form a uniform dispersion, and the auxiliary dispersant polyethylene glycol and a small amount of acetone are mixed at a mass ratio of 1:2-1:2.5 to form a uniform dispersion. After stirring to form dispersions, the solvents are removed by heating to 45-55°C and evaporating under reduced pressure to obtain pretreated main dispersant stearic acid and auxiliary dispersant polyethylene glycol.

[0029] In an achievable manner of the first aspect, the method for producing the flame retardant masterbatch comprises the following steps:

[0030] S1: Add nitrogen flame retardant, phosphorus flame retardant, ethylene bis stearamide and PA66 into a high-speed mixer in proportion, and mix at a speed of 600-700 rpm for 6-8 minutes to make the components preliminarily mixed evenly, in preparation for subsequent extrusion granulation, to ensure that the components can better interact and fuse during the extrusion process.

[0031] S2: The premixed materials are then extruded and granulated through a twin-screw extruder, the temperature of the twin-screw extruder is set to: zone 1 temperature 170-180°C, zone 2 temperature 190-200°C, zone 3 temperature 210-220°C, zone 4 temperature 230-240°C, the screw speed is 160-180 rpm, the materials are melted, mixed and extruded in the extruder to form flame retardant masterbatch.

[0032] The materials are melted, mixed and extruded in the extruder to form flame retardant masterbatch. In this process, the components are further mixed evenly and form uniform particles under the action of appropriate temperature and shear force. Different temperature zones can gradually melt and mix the materials, ensuring the uniformity and stability of the internal structure of the flame retardant masterbatch.

[0033] S3: The extruded masterbatch is cooled by air cooling and then screened to remove unqualified large particles and sticky particles to obtain flame retardant masterbatch with uniform particle size.

[0034] The nitrogen flame retardant is melamine cyanurate, which releases inert gases such as nitrogen when burning to achieve gas phase flame retardancy; the phosphorus flame retardant is melamine polyphosphate, which can promote the carbonization of the material surface to form a solid phase flame retardant layer. When the two work together, the inert gas released by the nitrogen flame retardant can prevent oxygen from contacting the carbon layer formed by the phosphorus flame retardant, making it more stable in its role of heat insulation and oxygen isolation. At the same time, the presence of the carbon layer also helps to maintain the inert gas released by the nitrogen flame retardant, making the gas phase flame retardant effect more durable.

[0035] In addition, ethylene bisstearamide improves the dispersibility of nitrogen-based flame retardants and phosphorus-based flame retardants during the preparation of masterbatches, allowing them to be more evenly distributed in the PA66 carrier, and then more evenly dispersed when mixed with the PPA matrix. PA66, as a carrier, provides a dispersion medium for nitrogen-based flame retardants and phosphorus-based flame retardants, which can evenly wrap these two flame retardants and slowly release them when mixed with the PPA matrix, ensuring the uniform distribution of flame retardants in the material, helping to form a uniform flame retardant system throughout the material, so that each local area can play a flame retardant role during combustion, and the flame retardant properties and thermal stability of PA66 itself complement the nitrogen-based flame retardants and phosphorus-based flame retardants, and jointly improve the flame retardant properties of the material.

[0036] In an achievable manner of the first aspect, the glass fiber is a surface-modified modified glass fiber having a diameter of 10 to 12 μm;

[0037] And / or, first treat with a bifunctional silane coupling agent in which KH~560 and KH~550 are mixed in a ratio of 1:1.2~1:1.5, and the total amount of silane coupling agent is 1.2%~1.4% of the mass of the glass fiber; the hydrolyzable groups in the silane coupling agent molecules (such as the ethoxy group of KH~560 and the methoxy group of KH~550) are hydrolyzed in the presence of water to generate silanol groups, and the silanol groups undergo condensation reactions with the hydroxyl groups on the surface of the glass fiber to form chemical bonds, while the organic functional groups at the other end of the coupling agent molecules (such as the epoxy group of KH~560 and the amino group of KH~550) can undergo chemical reactions or physical adsorption with the PPA matrix molecular chain.

[0038] The glass fiber modified by the silane coupling agent is then treated with an interfacial compatibilizer using ethylene-ethyl acrylate copolymer grafted with maleic anhydride, and the amount used is 3.5% to 4.5% of the mass of the glass fiber.

[0039] The maleic anhydride group has high reactivity and can further react with the active groups remaining on the surface of the glass fiber. The ethylene-ethyl acrylate copolymer part has good compatibility with the PPA matrix and can play a filling and lubricating role between the glass fiber and the PPA matrix. Through this double surface modification treatment, the bonding force between the glass fiber and the PPA matrix is ​​enhanced, the dispersibility is improved, the material strength and flame retardant properties are improved, and the glass fiber is effectively prevented from forming stress concentration points and flame propagation channels in the material.

[0040] In an achievable manner of the first aspect, in the mixing process:

[0041] First, the dried graft copolymer modified PPA resin and the auxiliary dispersant polyethylene glycol are mixed at low speed in a high-speed mixer for 4 to 5 minutes to evenly disperse the polyethylene glycol in the PPA matrix and preliminarily improve the compatibility of PPA with the filler; then add the mixed filler wrapped by stearic acid and mix at medium speed for 5 to 6 minutes. When mixing the filler, use intermittent stirring, that is, stir for 30 to 40 seconds, pause for 10 to 12 seconds, and repeat this cycle. The intermittent stirring method can avoid damage to the filler and the matrix due to excessive shearing, while ensuring that the filler is evenly dispersed in the matrix. Finally, add the composite antioxidant and other additives and mix at high speed for 7 to 8 minutes to ensure that the components are fully mixed. In the entire mixing process, the stirring speed and time at different stages need to be precisely controlled to achieve good dispersion and mixing of the components while keeping the material properties from being affected by excessive processing.

[0042] In the first aspect, in the extrusion molding process, the temperature of the first zone of the twin-screw extruder is set to 240-250°C, the temperature of the second zone is 260-270°C, the temperature of the third zone is 280-290°C, and the temperature of the fourth zone is 300-310°C; the temperature setting adopts a step-by-step increase method so that the material can be smoothly transformed from a solid state to a molten state and fully mixed. The lower temperature of the first zone softens the material initially, and as the material moves forward, the temperature rises to completely melt it, thereby ensuring the continuity and stability of the extrusion process.

[0043] And / or, the screw speed is 250~300 rpm, the die temperature is 300~310°C, an exhaust section is set in the middle of the twin-screw extruder, and the vacuum degree is maintained at ~0.07~-0.08MPa; the reasonable control of the screw speed and die temperature can ensure that the material is subjected to appropriate shear and pressure in the extruder, so that the components are better integrated. The exhaust section can discharge the air and low molecular volatiles in the material, making the product denser and improving the material performance.

[0044] And / or, the material extruded by the twin-screw extruder is sequentially subjected to water cooling and air cooling, wherein the water cooling allows the material to quickly cool down and shape, and the air cooling further cools the material to room temperature and removes water, thereby ensuring that the product size is stable and avoiding excessive temperature affecting material properties, and the finished product is obtained after screening and sorting.

[0045] In a second aspect, the present invention provides a high-performance flame-retardant reinforced PPA composite material, which is prepared by the production method of the high-performance flame-retardant reinforced PPA composite material.

[0046] In a method that can be realized in the second aspect, the raw materials include at least the following components in percentage by mass: 35% to 42% of graft copolymer modified PPA resin, 0.6% to 0.8% of composite antioxidant, 0.5% to 0.7% of composite dispersant, 30% to 40% of glass fiber, 20% to 23% of flame retardant masterbatch, and 3% to 5% of other additives;

[0047] As a reinforcing filler, glass fiber can significantly improve the strength of PPA materials. High filling amount (30%-40%) of glass fiber effectively enhances the material's bearing capacity through interaction with the PPA matrix, enabling it to meet application scenarios with strict requirements on mechanical properties. In addition, glass fiber can limit the expansion and contraction of the PPA matrix when heated or stressed, making the material's size more stable.

[0048] Flame retardant masterbatch can make the composite material reach UL94V0 flame retardant grade through reasonable formula (nitrogen flame retardant content is 40%-60%, phosphorus flame retardant content is 5%-8%, ethylene bis stearamide content is 1%-3% and PA66 content is 30-50%).

[0049] And / or, the composite dispersant includes a main dispersant stearic acid content of 0.3% to 0.4% and an auxiliary dispersant polyethylene glycol content of 0.2% to 0.3%. The main dispersant stearic acid in the composite dispersant can be adsorbed on the surface of the filler to reduce the interaction between the fillers, and the auxiliary dispersant polyethylene glycol further improves the dispersion effect. The synergistic effect of the two makes the fillers such as glass fibers evenly dispersed in the PPA matrix, avoiding stress concentration and agglomeration, and improving the mechanical properties and flame retardant properties of the material.

[0050] And / or, the molecular weight of the auxiliary dispersant polyethylene glycol is 500-600.

[0051] When the molecular weight of polyethylene glycol is between 500 and 600, its molecular chain length is moderate. It can not only be adsorbed on the surface of fillers such as glass fibers, but also prevent the agglomeration of filler particles due to interactions such as van der Waals forces through steric hindrance effects; it can also act as a "bridge" between the filler and the matrix, improving the interfacial compatibility between the filler and the PPA matrix.

[0052] And / or, the composite antioxidant includes antioxidant AO9 with a content of 0.2% to 0.3%, antioxidant 608 with a content of 0.2% to 0.3% and antioxidant 1010 with a content of 0.2% to 0.3%.

[0053] Antioxidant AO9 can react with hydroperoxides, decomposing them into relatively stable compounds such as alcohols and ketones, reducing the generation of free radicals, thereby inhibiting the oxidative aging of materials; antioxidant 608 may perform well in capturing a certain type of free radicals, while antioxidant 1010 has a good effect in decomposing hydroperoxides. They work together to more comprehensively and effectively inhibit the oxidation reaction of PPA materials during processing and use, providing better antioxidant protection.

[0054] Other additives include nano-montmorillonite with a content of 3% to 4% and calcium stearate with a content of 0.7% to 1%. Nano-montmorillonite has a unique lamellar structure that can further improve the mechanical properties and flame retardant properties of the material, while calcium stearate can improve the processing properties of the material.

[0055] In the present invention, there is a close coordination between the various components. The graft copolymerization modification of PPA improves its compatibility with the flame retardant masterbatch and the glass fiber, so that the flame retardant in the flame retardant masterbatch can play a better role and the glass fiber can more effectively enhance the material performance; the composite dispersant promotes the dispersion of the glass fiber and the flame retardant masterbatch in the PPA matrix, further enhancing the performance uniformity of the material; the surface modification of the glass fiber enhances its bonding strength with the PPA matrix, and also helps to improve the flame retardant performance.

[0056] The flame retardant masterbatch comprises the following components in percentage by mass: 45% to 55% nitrogen flame retardant, 6% to 8% phosphorus flame retardant, 1.5% to 2.5% ethylene bis stearamide and 30% to 40% PA66;

[0057] The nitrogen-based flame retardant is melamine cyanurate, which releases inert gases such as nitrogen during combustion to achieve gas phase flame retardancy; the phosphorus-based flame retardant is melamine polyphosphate, which can promote carbonization of the material surface to form a solid phase flame retardant layer.

[0058] The various components in the flame retardant masterbatch work synergistically to form an effective flame retardant system, which works together with other components to improve the comprehensive performance of the material; other additives such as nano-montmorillonite and calcium stearate complement and optimize the entire system in terms of reinforcement and processing performance, respectively.

[0059] However, there are also certain restrictions between the components. For example, if the grafting rate of PPA is too high, the rigidity of the material may be slightly reduced; if the content of glass fiber is too high, it may affect the processing fluidity and dispersibility of the material; and if some components in the flame retardant masterbatch are not in the right proportion, it may affect the flame retardant effect or other properties of the material. Therefore, in the process of formula design and preparation, it is necessary to accurately control the proportion of each component and the process parameters to achieve the best synergy between the components and overcome possible adverse factors.

[0060] In a manner that can be realized in the second aspect, the high-performance flame-retardant reinforced PPA composite material has a flame retardant grade of UL94V0, a ​​tensile strength of 230-250 MPa, and a flexural strength of 330-350 MPa.

[0061] Achieving good compatibility of PPA with flame retardant masterbatch and glass fiber is a key difficulty. Due to the chemical structure characteristics of PPA itself, its interaction with flame retardants and glass fibers is weak. In the present invention, hydroxyethyl acrylate is used to graft copolymerize PPA, which significantly improves the compatibility of PPA with other components, which is an important innovation that distinguishes it from traditional PPA composite materials. Through this modification, the degradation of material performance caused by compatibility problems is effectively solved, laying the foundation for the preparation of high-performance composite materials.

[0062] Compared with the prior art, the present invention has the following beneficial effects:

[0063] (1) The present invention adopts hydroxyethyl acrylate to graft copolymerize PPA, which significantly improves the compatibility of PPA with other components, which is an important innovation that distinguishes it from traditional PPA composite materials. Through this modification, the degradation of material performance caused by compatibility problems is effectively solved, laying a foundation for the preparation of high-performance composite materials.

[0064] (2) The present invention achieves a good balance in flame retardancy, mechanical properties, dispersibility and antioxidant properties through the graft copolymerization modification of PPA and the optimization and synergistic effect of various raw material components. The flame retardancy grade stably reaches UL94V0, the tensile strength can reach 230~250MPa, the bending strength can reach 330~350MPa, and the performance is stable during long-term use.

[0065] (3) The present invention uses the synergistic effect of nitrogen-based flame retardants and phosphorus-based flame retardants, combined with other components in the flame retardant masterbatch and glass fiber surface modification to improve the flame retardant properties, so that the composite material can reach the UL94V0 flame retardant grade and meet the needs of application scenarios with extremely high fire safety requirements.

[0066] (4) The modification of PPA and the surface treatment of glass fiber in the present invention significantly enhance the interfacial bonding force between the filler and the matrix. At the same time, the composite dispersant ensures the uniform dispersion of the filler in the matrix, effectively avoids stress concentration and agglomeration, improves the reliability and durability of the material, prolongs the service life of the material, and broadens its application field. It can be widely used in industries with strict requirements on material performance, such as automobiles, electronic appliances, and aerospace.

[0067] (5) The main dispersant stearic acid and the auxiliary dispersant polyethylene glycol in the composite dispersant of the present invention work synergistically to evenly disperse fillers such as glass fibers in the PPA matrix, thereby avoiding stress concentration and agglomeration caused by uneven dispersion, thereby improving the mechanical properties and flame retardant properties of the material.

[0068] (6) The effects of the composite dispersant and other additives in the present invention and the reasonable setting of process parameters make the material have good processing fluidity, easy molding in the process of injection molding, extrusion, etc., high product dimensional accuracy, good surface quality, reduced production costs, and improved production efficiency and product qualification rate.

[0069] The present invention will be explained in detail below with reference to specific embodiments. DETAILED DESCRIPTION

[0070] In order to facilitate the understanding of the present invention, the present invention will be described in more detail below. The present invention is not limited to the embodiments described in the text. On the contrary, these embodiments are provided to make the content disclosed in the present invention more thorough and comprehensive.

[0071] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly connected by technicians in the technical field to which the present invention belongs. The terminology used in the specification of the present invention is for the purpose of describing specific embodiments and is not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0072] Embodiment 1: In a first aspect, the embodiment of the present invention provides a high-performance flame-retardant reinforced PPA composite material, wherein the raw materials include the following components in percentage by mass:

[0073] PPA resin 40% (modified by graft copolymerization);

[0074] Composite antioxidant 0.75% (antioxidant AO9 takes 0.25%, antioxidant 608 takes 0.25%, antioxidant 1010 takes 0.25%);

[0075] Composite dispersant 0.6% (main dispersant stearic acid 0.35%, auxiliary dispersant polyethylene glycol 0.25%), wherein the molecular weight of the auxiliary dispersant polyethylene glycol is 550;

[0076] Glass fiber 32% (modified glass fiber with surface modification and a diameter of 10 μm);

[0077] The flame retardant masterbatch is 22%, of which nitrogen flame retardant (melamine cyanurate) is 50%, phosphorus flame retardant (melamine polyphosphate) is 7%, ethylene bisstearamide is 2% and PA66 is 41%.

[0078] Other additives 4.65%: nano-montmorillonite 3.85%, calcium stearate 0.8%.

[0079] In a second aspect, an embodiment of the present invention further provides a method for producing a high-performance flame-retardant reinforced PPA composite material, which is used to prepare the above-mentioned high-strength PPA flame-retardant composite material, and comprises the following steps:

[0080] (1) PPA graft copolymerization modification, specifically including the following steps:

[0081] (11) Add dried PPA resin and toluene solution in a ratio of 1:3, start stirring to completely dissolve PPA in the toluene solution to form a homogeneous solution, and then slowly drop the hydroxyethyl acrylate solution containing the initiator under nitrogen protection. The dropping time is controlled within 30 minutes to ensure that the initiator is evenly dispersed in the reaction system to initiate the grafting reaction. The mass ratio of PPA resin to hydroxyethyl acrylate is 1:9; the amount of initiator used is 0.6% of the mass of the PPA resin.

[0082] (12) The grafting reaction was carried out at 90 °C for 5 hours to ensure that the grafting reaction proceeded as expected and the grafting rate was maintained stable at 10% to 15%. After the reaction was completed, the modified PPA resin was precipitated, filtered, washed, and dried.

[0083] (2) Dispersant pretreatment: Stearic acid and ethanol were mixed in a ratio of 1:2.8 to form a dispersion, and polyethylene glycol and acetone were mixed in a ratio of 1:2.2 to form a dispersion. The mixtures were stirred and heated to 50°C and evaporated under reduced pressure to remove the solvent.

[0084] (3) Filler premixing: premix the pretreated stearic acid with the surface-modified glass fiber and flame retardant masterbatch.

[0085] The specific steps of the surface modification treatment of the glass fiber are: firstly, the glass fiber is surface-modified using a bifunctional silane coupling agent in which KH-560 and KH-550 are mixed in a ratio of 1:1.3 (the total amount of the silane coupling agent is 1.3% of the mass of the glass fiber), and then treated with ethylene-ethyl acrylate copolymer grafted with maleic anhydride (the amount is 4% of the mass of the glass fiber).

[0086] The production method of the flame retardant masterbatch comprises the following steps:

[0087] S1: Add nitrogen flame retardant, phosphorus flame retardant, ethylene bis stearamide and PA66 into a high-speed mixer according to the above proportions, and mix at a speed of 600 rpm for 8 minutes to preliminarily mix the components;

[0088] S2: The premixed material is then extruded and granulated through a twin-screw extruder, the temperature of the twin-screw extruder is set to: 170°C for zone 1, 190°C for zone 2, 220°C for zone 3, and 230°C for zone 4, the screw speed is 180 rpm, and the material is melted, mixed, and extruded in the extruder to form a flame retardant masterbatch;

[0089] S3: The extruded masterbatch is cooled by air cooling and then screened to remove unqualified large particles and sticky particles to obtain flame retardant masterbatch with uniform particle size.

[0090] (4) PPA drying treatment: Dry the graft copolymer modified PPA resin to a moisture content of less than 0.03%.

[0091] (5) Mixing process: First, the dried modified PPA and the auxiliary dispersant polyethylene glycol are mixed at a low speed in a high-speed mixer for 4.5 minutes, and the mixed filler wrapped by stearic acid is added and mixed at a medium speed for 5.5 minutes. When mixing the filler, an intermittent stirring method is adopted, that is, stirring for 35 seconds, pausing for 11 seconds, and repeating this cycle. Finally, the composite antioxidant and other additives are added and mixed at a high speed for 7.5 minutes.

[0092] (6) Extrusion molding: The mixed material is conveyed to a twin-screw extruder for extrusion. The extruded material is water-cooled and air-cooled in turn, and the finished product is obtained after screening and sorting. The temperature of the first zone of the twin-screw extruder is 245°C, the temperature of the second zone is 265°C, the temperature of the third zone is 285°C, and the temperature of the fourth zone is 305°C; the screw speed is 280 rpm, the head temperature is 305°C, and an exhaust section is set in the middle of the twin-screw extruder, and the vacuum degree is maintained at -0.075MPa.

[0093] Embodiment 2: The embodiment of the present invention provides a high-performance flame-retardant reinforced PPA composite material, the raw materials include the following components in mass percentage:

[0094] PPA resin 35% (modified by graft copolymerization);

[0095] Composite antioxidant 0.8%: antioxidant AO9 takes 0.2%, antioxidant 608 takes 0.3%, antioxidant 1010 takes 0.3%.

[0096] Composite dispersant 0.5%: main dispersant stearic acid takes 0.3%, auxiliary dispersant polyethylene glycol (molecular weight 500) takes 0.2%.

[0097] Glass fiber 37%, (modified glass fiber with surface modification and a diameter of 11μm);

[0098] The flame retardant masterbatch accounts for 23%, of which nitrogen flame retardant accounts for 53%, phosphorus flame retardant accounts for 6%, ethylene bis stearamide accounts for 1.8% and PA66 accounts for 39.2%.

[0099] Other additives: 3% nano-montmorillonite and 0.7% calcium stearate.

[0100] The embodiment of the present invention also provides a method for producing a high-performance flame-retardant reinforced PPA composite material, which is used to prepare the above-mentioned high-strength PPA flame-retardant composite material. The basic steps are the same as those in Example 1, except that:

[0101] (1) PPA graft copolymerization modification, specifically including the following steps:

[0102] (11) Add dried PPA resin and toluene solution in a ratio of 1:4, start stirring to completely dissolve PPA in the toluene solution to form a homogeneous solution, and then slowly drop the hydroxyethyl acrylate solution containing the initiator under nitrogen protection. The dropping time is controlled within 36 minutes to ensure that the initiator is evenly dispersed in the reaction system to initiate the grafting reaction. The mass ratio of PPA resin to hydroxyethyl acrylate is 1:8; the amount of initiator used is 0.7% of the mass of the PPA resin.

[0103] (12) The grafting reaction was carried out at 95 °C for 6 hours to ensure that the grafting reaction proceeded as expected and the grafting rate was maintained stable at 10% to 15%. After the reaction was completed, the modified PPA resin was precipitated, filtered, washed, and dried.

[0104] The steps and related parameters of dispersant pretreatment (2), filler premixing (3), and PPA drying treatment (4) are the same as those in Example 1.

[0105] The steps and related parameters of the glass fiber surface modification treatment are the same as those in Example 1.

[0106] The production method of the flame retardant masterbatch comprises the following steps:

[0107] S1: Add nitrogen flame retardant, phosphorus flame retardant, ethylene bis stearamide and PA66 into a high-speed mixer according to the above proportions, and mix at a speed of 700 rpm for 6 minutes to preliminarily mix the components;

[0108] S2: The premixed material is then extruded and granulated through a twin-screw extruder, the temperature of the twin-screw extruder is set to: 180°C for zone 1, 200°C for zone 2, 210°C for zone 3, 240°C for zone 4, and the screw speed is 170 rpm. The material is melted, mixed, and extruded in the extruder to form a flame retardant masterbatch;

[0109] S3: The extruded masterbatch is cooled by air cooling and then screened to remove unqualified large particles and sticky particles to obtain flame retardant masterbatch with uniform particle size.

[0110] (5) Mixing process: First, the dried modified PPA and the auxiliary dispersant polyethylene glycol are mixed at a low speed in a high-speed mixer for 4 minutes, and the mixed filler coated with the main dispersant stearic acid is added and mixed at a medium speed for 5 minutes. When mixing the filler, an intermittent stirring method is adopted, that is, stirring for 32 seconds, pausing for 10 seconds, and repeating this cycle. Finally, the composite antioxidant and other additives are added and mixed at a high speed for 8 minutes.

[0111] (6) Extrusion molding: The mixed material is conveyed to a twin-screw extruder for extrusion. The extruded material is water-cooled and air-cooled in turn, and the finished product is obtained after screening and sorting. The temperature of the first zone of the twin-screw extruder is 240°C, the temperature of the second zone is 260°C, the temperature of the third zone is 280°C, and the temperature of the fourth zone is 300°C; the screw speed is 260 rpm, the head temperature is 300°C, and an exhaust section is set in the middle of the twin-screw extruder, and the vacuum degree is maintained at -0.07MPa.

[0112] Embodiment 3: The embodiment of the present invention provides a high-performance flame-retardant reinforced PPA composite material, the raw materials include the following components in mass percentage:

[0113] PPA resin 42% (modified by graft copolymerization);

[0114] Compound antioxidant 0.8%: antioxidant AO9 takes 0.3%, antioxidant 608 takes 0.2%, antioxidant 1010 takes 0.3%;

[0115] Composite dispersant 0.7%: main dispersant stearic acid 0.4%, auxiliary dispersant polyethylene glycol (molecular weight 600) 0.3%;

[0116] Glass fiber 31.5%, (modified glass fiber with surface modification and a diameter of 11μm);

[0117] Flame retardant masterbatch 20%, of which nitrogen flame retardant takes 48%, phosphorus flame retardant takes 8%, ethylene bis stearamide takes 2.2% and PA66 takes 41.8%.

[0118] Other additives 5%: nano-montmorillonite 4%, calcium stearate 1%.

[0119] Preparation process: The surface modification of glass fiber is the same as in Example 1;

[0120] The embodiment of the present invention also provides a method for producing a high-performance flame-retardant reinforced PPA composite material, which is used to prepare the above-mentioned high-strength PPA flame-retardant composite material. The basic steps are the same as those in Example 1, except that:

[0121] (1) PPA graft copolymerization modification, specifically including the following steps:

[0122] (11) Add dried PPA resin and toluene solution in a ratio of 1:3.5, start stirring to completely dissolve PPA in the toluene solution to form a homogeneous solution, and then slowly drop the hydroxyethyl acrylate solution containing the initiator under nitrogen protection. The dropping time is controlled within 45 minutes to ensure that the initiator is evenly dispersed in the reaction system to initiate the grafting reaction. The mass ratio of PPA resin to hydroxyethyl acrylate is 1:8.5; the amount of initiator used is 0.8% of the mass of the PPA resin.

[0123] (12) The grafting reaction was carried out at 90 °C for 7 hours to ensure that the grafting reaction proceeded as expected and the grafting rate was maintained stable at 10% to 15%. After the reaction was completed, the modified PPA resin was precipitated, filtered, washed, and dried.

[0124] The steps and related parameters of dispersant pretreatment (2), filler premixing (3), and PPA drying treatment (4) are the same as those in Example 1.

[0125] The steps and related parameters of the glass fiber surface modification treatment are the same as those in Example 1.

[0126] The production method of the flame retardant masterbatch comprises the following steps:

[0127] S1: Add nitrogen flame retardant, phosphorus flame retardant, ethylene bis stearamide and PA66 into a high-speed mixer according to the above proportions, and mix at a speed of 680 rpm for 8 minutes to preliminarily mix the components;

[0128] S2: The premixed material is then extruded and granulated through a twin-screw extruder, the temperature of the twin-screw extruder is set to: 1750°C in zone 1, 195°C in zone 2, 215°C in zone 3, 240°C in zone 4, and the screw speed is 160 rpm. The material is melted, mixed, and extruded in the extruder to form a flame retardant masterbatch;

[0129] S3: The extruded masterbatch is cooled by air cooling and then screened to remove unqualified large particles and sticky particles to obtain flame retardant masterbatch with uniform particle size.

[0130] (5) Mixing process: First, the dried modified PPA and the auxiliary dispersant polyethylene glycol are mixed at a low speed in a high-speed mixer for 5 minutes, and the mixed filler coated with the main dispersant stearic acid is added and mixed at a medium speed for 6 minutes. When mixing the filler, an intermittent stirring method is adopted, that is, stirring for 38 seconds and pausing for 12 seconds in a cycle). Finally, the composite antioxidant and other additives are added and mixed at a high speed for 7 minutes.

[0131] (6) Extrusion molding: The mixed material is conveyed to a twin-screw extruder for extrusion. The extruded material is water-cooled and air-cooled in turn, and the finished product is obtained after screening and sorting. The temperature of the first zone of the twin-screw extruder is 250°C, the temperature of the second zone is 270°C, the temperature of the third zone is 290°C, and the temperature of the fourth zone is 310°C; the screw speed is 290 rpm, the head temperature is 310°C, and an exhaust section is set in the middle of the twin-screw extruder, and the vacuum degree is maintained at -0.08MPa.

[0132] Comparative Example 1: The comparative example of the present invention provides a reinforced PPA composite material, the raw materials include the following components in mass percentage:

[0133] Unmodified PPA resin 40%;

[0134] Composite antioxidant 0.75%: antioxidant AO9 takes 0.25%, antioxidant 608 takes 0.25%, antioxidant 1010 takes 0.25%;

[0135] Composite dispersant 0.6%: main dispersant stearic acid 0.35%, auxiliary dispersant polyethylene glycol (molecular weight 550) 0.25%;

[0136] The glass fiber is 32.35%, and the surface is modified only by a bifunctional silane coupling agent of KH-560 and KH-550 mixed in a ratio of 1:1.3 (the total amount of silane coupling agent is 1.3% of the mass of the glass fiber), and no maleic anhydride grafted ethylene-ethyl acrylate copolymer is used.

[0137] The flame retardant masterbatch is 22%, of which nitrogen flame retardant (melamine cyanurate) is 50%, phosphorus flame retardant (melamine polyphosphate) is 7%, ethylene bisstearamide is 2% and PA66 is 41%.

[0138] Other additives 4.3%: nano-montmorillonite 3.5%, calcium stearate 0.8%.

[0139] The comparative example of the present invention also provides a method for producing a reinforced PPA composite material, comprising the following steps:

[0140] (1) Dispersant pretreatment: Stearic acid and ethanol were mixed at a ratio of 1:2.8 to form a dispersion, and polyethylene glycol and acetone were mixed at a ratio of 1:2.2 to form a dispersion. The mixtures were stirred and heated to 50°C and evaporated under reduced pressure to remove the solvent.

[0141] (2) Filler premixing: premix the pretreated stearic acid with glass fiber and flame retardant masterbatch.

[0142] (3) PPA drying treatment: Dry the PPA resin until the moisture content is less than 0.03%.

[0143] (4) Mixing process: First, the dried PPA and polyethylene glycol are mixed at a low speed in a high-speed mixer for 4.5 minutes, and the mixed filler coated with stearic acid is added and mixed at a medium speed for 5.5 minutes (stirring for 35 seconds, pausing for 11 seconds in a cycle), and finally, the composite antioxidant and other additives are added and mixed at a high speed for 7.5 minutes.

[0144] (5) Extrusion molding: The mixed material is conveyed to a twin-screw extruder (zone 1 temperature 245°C, zone 2 temperature 265°C, zone 3 temperature 285°C, zone 4 temperature 305°C; screw speed 280 rpm, die head temperature 305°C, middle exhaust section vacuum degree -0.075 MPa) for extrusion, and the finished product is obtained after water cooling, air cooling, screening and sorting.

[0145] Comparative Example 2: The comparative example of the present invention provides a reinforced PPA composite material, the raw materials include the following components in mass percentage:

[0146] PPA resin 40% (modified by graft copolymerization, the mass ratio of hydroxyethyl acrylate to PPA is 7:1, and the amount of initiator benzoyl peroxide is 0.8% of the mass of PPA);

[0147] Composite antioxidant 0.75%: antioxidant AO9 takes 0.25%, antioxidant 608 takes 0.25%, antioxidant 1010 takes 0.25%.

[0148] Composite dispersant 0.6%: main dispersant stearic acid takes 0.35%, auxiliary dispersant polyethylene glycol (molecular weight 550) takes 0.25%.

[0149] Glass fiber 32.35%, without any surface modification.

[0150] The flame retardant masterbatch is 22%, of which nitrogen flame retardant (melamine cyanurate) is 50%, phosphorus flame retardant (melamine polyphosphate) is 7%, ethylene bisstearamide is 2% and PA66 is 41%.

[0151] Other additives: 3.5% nano-montmorillonite and 0.8% calcium stearate.

[0152] The comparative example of the present invention also provides a method for producing a reinforced PPA composite material, comprising the following steps:

[0153] (1) PPA graft copolymerization modification: PPA and hydroxyethyl acrylate are added to toluene in proportion, and an initiator, benzoyl peroxide, is added. The mixture is reacted at 75°C for 3 hours. After the reaction is completed, the modified PPA resin is obtained by precipitation, filtration, washing, and drying.

[0154] (2) Dispersant pretreatment: Stearic acid and ethanol were mixed in a ratio of 1:2.8 to form a dispersion, and polyethylene glycol and acetone were mixed in a ratio of 1:2.2 to form a dispersion. The mixtures were stirred and heated to 50°C and evaporated under reduced pressure to remove the solvent.

[0155] (3) Filler premixing: premix the pretreated stearic acid with glass fiber and flame retardant masterbatch.

[0156] (4) PPA drying treatment: The modified PPA resin is dried to a moisture content of less than 0.03%.

[0157] (5) Mixing process: First, the dried modified PPA and polyethylene glycol are mixed at a low speed in a high-speed mixer for 4.5 minutes, and the mixed filler coated with stearic acid is added and mixed at a medium speed for 5.5 minutes (stirring for 35 seconds, pausing for 11 seconds in a cycle), and finally, the composite antioxidant and other additives are added and mixed at a high speed for 7.5 minutes.

[0158] (6) Extrusion molding: The mixed material is conveyed to a twin-screw extruder (zone 1 temperature 245°C, zone 2 temperature 265°C, zone 3 temperature 285°C, zone 4 temperature 305°C; screw speed 280 rpm, die head temperature 305°C, middle exhaust section vacuum degree -0.075 MPa) for extrusion, and the finished product is obtained after water cooling, air cooling, screening and sorting.

[0159] Comparative Example 3: The comparative example of the present invention provides a reinforced PPA composite material, the raw materials include the following components in mass percentage:

[0160] PPA resin 40% (unmodified);

[0161] Composite antioxidant 0.75%: antioxidant AO9 takes 0.25%, antioxidant 608 takes 0.25%, antioxidant 1010 takes 0.25%.

[0162] Composite dispersant 0.6%: main dispersant stearic acid takes 0.35%, auxiliary dispersant polyethylene glycol (molecular weight 550) takes 0.25%.

[0163] Glass fiber 32.35%, the glass fiber is first surface-modified with a bifunctional silane coupling agent of KH-560 and KH-550 mixed in a ratio of 1:1.3 (the total amount of silane coupling agent is 1.3% of the mass of the glass fiber), and then treated with ethylene-ethyl acrylate copolymer grafted with maleic anhydride (the amount is 4% of the mass of the glass fiber);

[0164] Flame retardant masterbatch 22%, of which nitrogen flame retardant (melamine cyanurate) takes 50%, phosphorus flame retardant (melamine polyphosphate) takes 7%, ethylene bis stearamide takes 2% and PA66 takes 41%;

[0165] Other additives: 3.5% nano-montmorillonite, 0.8% calcium stearate;

[0166] The comparative example of the present invention also provides a method for producing a reinforced PPA composite material, comprising the following steps:

[0167] (1) Dispersant pretreatment: Stearic acid and ethanol were mixed at a ratio of 1:2.8 to form a dispersion, and polyethylene glycol and acetone were mixed at a ratio of 1:2.2 to form a dispersion. The mixtures were stirred and heated to 50°C and evaporated under reduced pressure to remove the solvent.

[0168] (2) Filler premixing: premix the pretreated stearic acid with glass fiber and flame retardant masterbatch.

[0169] (3) PPA drying treatment: Dry the PPA resin until the moisture content is less than 0.03%.

[0170] (4) Mixing process: First, the dried PPA and polyethylene glycol are mixed at a low speed in a high-speed mixer for 4.5 minutes, and the mixed filler coated with stearic acid is added and mixed at a medium speed for 5.5 minutes (stirring for 35 seconds, pausing for 11 seconds in a cycle), and finally, the composite antioxidant and other additives are added and mixed at a high speed for 7.5 minutes.

[0171] (5) Extrusion molding: The mixed material is conveyed to a twin-screw extruder (zone 1 temperature 245°C, zone 2 temperature 265°C, zone 3 temperature 285°C, zone 4 temperature 305°C; screw speed 280 rpm, die head temperature 305°C, middle exhaust section vacuum degree -0.075 MPa) for extrusion, and the finished product is obtained after water cooling, air cooling, screening and sorting.

[0172] The performance tests of the embodiments and comparative examples were carried out, and the results are shown in Table 1 below:

[0173] Table 1 is a comparative data table of material properties obtained in Examples 1-3 and Comparative Examples 1-3

[0174] Performance Indicators Flame retardant grade Tensile strength (MPa) Bending strength (MPa) Glass fiber dispersion Example 1 UL94V0 240 340 Uniform Example 2 UL94V0 235 335 Uniform Example 3 UL94V0 245 345 Uniform Comparative Example 1 Does not meet UL94V0 204 282 There is agglomeration Comparative Example 2 Does not meet UL94V0 192 265 Serious reunion Comparative Example 3 Does not meet UL94V0 211 300 Uniform but weak interface bonding

[0175] It can be seen from the above table that the composite materials prepared in Examples 1-3 all reach the UL94V0 grade in flame retardancy, and have a tensile strength between 230 and 250 MPa, a flexural strength between 330 and 350 MPa, uniform dispersion of glass fibers, and good material stability and processing performance.

[0176] In Comparative Example 1, since unmodified PPA resin is used and the glass fiber is not surface treated with ethylene-ethyl acrylate copolymer grafted with maleic anhydride, the interfacial bonding strength between the glass fiber and the PPA matrix is ​​insufficient, resulting in the tensile strength and flexural strength being reduced by about 15% and 18% respectively compared with Example 1, and the flame retardant performance is also reduced, failing to reach the UL94V0 grade.

[0177] In Comparative Example 2, since the grafting rate of the modified PPA resin is low and the glass fiber has not been surface-modified, obvious agglomeration occurs in the material and the dispersion is poor, resulting in the tensile strength and flexural strength being reduced by about 20% and 22% compared with Example 1. At the same time, the flame retardant performance is also affected and does not reach the UL94V0 level.

[0178] In Comparative Example 3, unmodified PPA was used. Although the treatment of glass fiber and flame retardant masterbatch was the same as in Example 1, due to the poor compatibility of PPA with other components, the overall performance of the material was reduced, and the tensile strength and flexural strength were reduced by about 12% and 15% compared with Example 1. The flame retardant performance was also slightly reduced and did not reach the UL94V0 level.

[0179] In summary, the present invention achieves significant improvement in the performance of the flame retardant reinforced PPA composite material through the graft copolymerization modification of PPA and the optimization of each raw material component and process steps, which has obvious advantages over the comparative example.

[0180] Any numerical value cited herein includes all values ​​of lower and upper values ​​that increase by one unit from the lower limit to the upper limit, and there is at least a two-unit interval between any lower value and any higher value. For example, if the value of the quantity of a component or a process variable (such as temperature, pressure, time, etc.) is stated to be from 1 to 90, preferably from 20 to 80, and more preferably from 30 to 70, the purpose is to illustrate that values ​​such as 15 to 85, 22 to 68, 43 to 51, 30 to 32 are also explicitly listed in the specification. For values ​​less than 1, one unit is appropriately considered to be 0.0001, 0.001, 0.01, 0.1. These are merely examples that are intended to be clearly expressed, and it can be considered that all possible combinations of numerical values ​​listed between the lowest value and the highest value are clearly stated in the specification in a similar manner.

[0181] Unless otherwise indicated, all ranges include the endpoints and all numbers between the endpoints. "About" or "approximately" used with a range applies to both endpoints of the range. Thus, "about 20 to 30" is intended to cover "about 20 to about 30", including at least the specified endpoints.

[0182] Many embodiments and many applications beyond the examples provided will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of the present teachings should not be determined with reference to the above description, but rather with reference to the appended claims and the full scope of equivalents to which such claims are entitled. For the purpose of comprehensiveness, all articles and references, including disclosures of patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the preceding claims is not intended to be a disclaimer of such subject matter, nor should it be considered that the inventors did not consider such subject matter to be part of the disclosed inventive subject matter.

[0183] The above is an exemplary description of the present invention. Obviously, the specific implementation of the present invention is not limited to the above-mentioned method. As long as such non-substantial improvements are made by adopting the method concept and technical solution of the present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A method for producing a high-performance flame-retardant reinforced PPA composite material, characterized in that: The following steps are involved: (1) PPA graft copolymerization modification: Using hydroxyethyl acrylate as a monomer, the PPA resin is modified under the action of an initiator to obtain a graft copolymerized PPA resin, and the grafting rate is maintained within the range of 10% to 15%; (2) Filler premixing: premix the main dispersant stearic acid with the surface-treated filler glass fiber and flame retardant masterbatch so that the stearic acid is fully adsorbed on the filler surface to form a uniform "coating layer"; The surface treatment method of the filler glass fiber comprises the following steps: First, treat with a bifunctional silane coupling agent of KH~560 and KH~550 mixed in a ratio of 1:1.2~1:1.5, and the total amount of silane coupling agent is 1.2%~1.4% of the mass of glass fiber; Then, the glass fiber modified by the silane coupling agent is treated with an interfacial compatibilizer using maleic anhydride grafted ethylene-ethyl acrylate copolymer, and the amount used is 3.5% to 4.5% of the mass of the glass fiber; (3) Drying treatment: Dry the PPA resin after graft copolymerization modification to make its moisture content less than 0.03%; (4) Mixing process: firstly, the dried graft copolymer modified PPA resin is mixed with the auxiliary dispersant polyethylene glycol, then the mixed filler wrapped by stearic acid is added for further mixing, and finally, the composite antioxidant and other additives are added; (5) Extrusion molding: The mixed material in step (4) is conveyed to a twin-screw extruder for extrusion.

2. The method for producing a high-performance flame-retardant reinforced PPA composite material according to claim 1, characterized in that: Add the dried PPA resin and toluene solution in proportion, start stirring to completely dissolve PPA in the toluene solution to form a homogeneous solution, then slowly drop the hydroxyethyl acrylate solution containing the initiator under nitrogen protection, and control the dropping time to 30-45 minutes to ensure that the initiator is evenly dispersed in the reaction system to initiate the grafting reaction, and obtain the graft copolymerized modified PPA resin; The reaction temperature of the grafting reaction is 85-95°C and the reaction time is 5-7h; And / or, the mass ratio of the PPA resin to hydroxyethyl acrylate is 1:9 to 1:8; And / or, the initiator is benzoyl peroxide, and its usage is 0.6% to 0.9% of the mass of the PPA resin.

3. The method for producing a high-performance flame-retardant reinforced PPA composite material according to claim 1, characterized in that: Also includes: Dispersant pretreatment: the main dispersant stearic acid and the auxiliary dispersant polyethylene glycol form a composite dispersant, and the main dispersant stearic acid and the auxiliary dispersant polyethylene glycol are pretreated; The main dispersant stearic acid and a small amount of ethanol are mixed at a mass ratio of 1:2.5-1:3 to form a uniform dispersion, and the auxiliary dispersant polyethylene glycol and a small amount of acetone are mixed at a mass ratio of 1:2-1:2.5 to form a uniform dispersion. After stirring to form dispersions, the solvents are removed by heating to 45-55°C and evaporating under reduced pressure to obtain pretreated main dispersant stearic acid and auxiliary dispersant polyethylene glycol.

4. The method for producing a high-performance flame-retardant reinforced PPA composite material according to claim 1, characterized in that: The production method of the flame retardant masterbatch comprises the following steps: S1: Add nitrogen flame retardant, phosphorus flame retardant, ethylene bis stearamide and PA66 into a high-speed mixer according to proportion, and mix at a speed of 600-700 rpm for 6-8 minutes to preliminarily mix the components; S2: The premixed material is then extruded and granulated through a twin-screw extruder, the temperature of the twin-screw extruder is set to: 170-180°C in zone 1, 190-200°C in zone 2, 210-220°C in zone 3, 230-240°C in zone 4, and the screw speed is 160-180 rev / min, the material is melted, mixed, and extruded in the extruder to form a flame retardant masterbatch; S3: The extruded masterbatch is cooled by air cooling and then screened to remove unqualified large particles and sticky particles to obtain flame retardant masterbatch with uniform particle size.

5. The method for producing a high-performance flame-retardant reinforced PPA composite material according to claim 1, characterized in that: The diameter of the surface treated glass fiber is 10~12μm.

6. The method for producing a high-performance flame-retardant reinforced PPA composite material according to claim 1, characterized in that: In the mixing process: First, the dried graft copolymer modified PPA resin and the auxiliary dispersant polyethylene glycol are mixed at a low speed in a high-speed mixer for 4 to 5 minutes, and then the mixed filler wrapped by stearic acid is added and mixed at a medium speed for 5 to 6 minutes. When mixing the filler, an intermittent stirring method is adopted, that is, stirring for 30 to 40 seconds, pausing for 10 to 12 seconds, and repeating this cycle. Finally, the composite antioxidant and other additives are added and mixed at a high speed for 7 to 8 minutes.

7. The method for producing a high-performance flame-retardant reinforced PPA composite material according to claim 1, characterized in that: In the extrusion molding process, the temperature of the first zone of the twin-screw extruder is set to 240-250°C, the temperature of the second zone is set to 260-270°C, the temperature of the third zone is set to 280-290°C, and the temperature of the fourth zone is set to 300-310°C; and / or, the screw speed is 250-300 rpm, the die temperature is 300-310°C, an exhaust section is provided in the middle of the twin-screw extruder, and the vacuum degree is maintained at -0.07-0.08 MPa; And / or, the material extruded by the twin-screw extruder is sequentially water-cooled and air-cooled, and screened and sorted to obtain a finished product.

8. A high-performance flame-retardant reinforced PPA composite material, characterized in that: The high-performance flame-retardant reinforced PPA composite material is prepared by the production method according to any one of claims 1 to 7.

9. A high-performance flame-retardant reinforced PPA composite material according to claim 8, characterized in that: The raw materials include at least the following components in percentage by mass: graft copolymer modified PPA resin 35%~42%, composite antioxidant 0.6%~0.8%, composite dispersant 0.5%~0.7%, glass fiber 30%~40%, flame retardant masterbatch 20%~23% and other additives 3%~5%; The composite dispersant includes a main dispersant, stearic acid, having a content of 0.3% to 0.4% and an auxiliary dispersant, polyethylene glycol, having a content of 0.2% to 0.3%; The composite antioxidant comprises antioxidant AO9 with a content of 0.2% to 0.3%, antioxidant 608 with a content of 0.2% to 0.3% and antioxidant 1010 with a content of 0.2% to 0.3%.

10. A high-performance flame-retardant reinforced PPA composite material according to claim 8 or 9, characterized in that: The flame retardant masterbatch comprises the following components in percentage by mass: 45% to 55% nitrogen flame retardant, 6% to 8% phosphorus flame retardant, 1.5% to 2.5% ethylene bis stearamide and 30% to 40% PA66; The nitrogen-based flame retardant is melamine cyanurate, and the phosphorus-based flame retardant is melamine polyphosphate; The high-performance flame-retardant reinforced PPA composite material has a flame-retardant grade of UL94V0, a ​​tensile strength of 230-250MPa, and a flexural strength of 330-350MPa.