Polypropylene composite material as well as preparation method and application thereof

Abstract

The invention discloses a polypropylene composite material as well as a preparation method and application thereof, and relates to the technical field of high polymer materials. The invention provides a polypropylene composite material. The polypropylene composite material is prepared from the following components in parts by weight: 25-50 parts of PP resin, 25-40 parts of hexagonal flaky magnesium hydroxide, 0.1-1.0 part of a silane coupling agent, 5-15 parts of an inorganic hypophosphite flame retardant, 10-20 parts of a macromolecular antistatic agent, 1-5 parts of an interface compatilizer and 0-0.5 part of a processing aid, the structural formula of the silane coupling agent is Y (CH2) nSi (OR) 3; the macromolecular antistatic agent is at least one of polyether amide antistatic agents and polyether ester amide antistatic agents. Through the cooperation of the specific components, the polypropylene composite material which can meet the requirements of flame retardance, static resistance, chemical resistance and good appearance at the same time is prepared.

Description

Technical Field

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

[0002] With the rapid development of industries such as electronics, aerospace, and transportation, the market demands increasingly stringent comprehensive performance requirements for polymer materials. Flame retardancy, antistatic properties, and chemical resistance are key functional characteristics for ensuring material safety. Among many polymer materials, polypropylene is widely used due to its excellent performance; however, it is inherently flammable, and its non-polar nature results in high surface resistance, making it prone to static charge accumulation. These defects severely limit polypropylene's application in scenarios with high safety requirements. To address the flame retardancy issue of polypropylene, adding inorganic flame retardants is one of the mainstream technical routes for polymer flame retardant modification. Among these, magnesium hydroxide (Mg(OH)2) has become a highly regarded and efficient flame retardant due to its environmental friendliness, non-toxicity, and excellent smoke suppression effects. To address the static electricity problem of polypropylene, existing technologies have proposed various solutions: traditional solutions often use small-molecule antistatic agents (such as quaternary ammonium salts and esters). These antistatic agents migrate to the material surface, adsorb environmental moisture, and form a conductive layer to dissipate charge. However, they have fatal flaws such as the antistatic effect being dependent on environmental humidity and the ease with which small molecules migrate and precipitate. The subsequently developed large-molecule long-lasting antistatic agents (such as polyetheramides) can dissipate charge by forming a conductive network in the matrix, and have the advantages of not being dependent on moisture and not being easily migrated. However, how to stably and efficiently introduce and fix them into the polypropylene composite system remains an unsolved technical challenge. Simple blending can easily cause the antistatic agent to separate from the matrix phase and disperse unevenly, thus affecting the overall performance of the material.

[0003] While there are existing technologies that combine polar polymers (such as PC / ABS) with antistatic agents and magnesium hydroxide for modification, the chemical resistance of PC / ABS is far inferior to that of polypropylene, which cannot meet the requirements of applications with specific chemical resistance requirements, such as the battery industry. Furthermore, when PC / ABS is combined with antistatic agents, the polar groups on the molecular chain form strong intermolecular forces with the polar segments of polyether amide, making it easier to bond. The bonding difficulty is much lower than that of polypropylene.

[0004] Therefore, a polypropylene composite material that can simultaneously satisfy the requirements of flame retardancy, antistatic properties, chemical resistance, and good appearance has broad application prospects. Summary of the Invention

[0005] Based on this, the purpose of the present invention is to overcome the shortcomings of the prior art and provide a polypropylene composite material that can simultaneously satisfy the requirements of flame retardancy, antistatic properties, chemical resistance, and maintaining a good appearance.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a polypropylene composite material, comprising the following components in parts by weight: 25-50 parts of PP resin, 25-40 parts of hexagonal flake magnesium hydroxide, 0.1-1.0 parts of silane coupling agent, 5-15 parts of inorganic hypophosphite flame retardant, 10-20 parts of polymeric antistatic agent, 1-5 parts of interface compatibilizer, and 0-0.5 parts of processing aid; the silane coupling agent has the structural formula Y(CH2)nSi(OR)3, wherein OR is one of methoxy and ethoxy, and Y is one of amino, epoxy, and methacryloxy, and n=1-4; the polymeric antistatic agent is at least one of polyether amide antistatic agent and polyether ester amide antistatic agent.

[0007] Preferably, the weight percentage of the PP resin is not less than 30% based on the total weight of the polypropylene composite material.

[0008] The selection of the silane coupling agent with a specific structure in this invention has two advantages. Firstly, its OR (hydrolyzable group) can react with residual water on the surface of magnesium hydroxide, hydrolyzing it into hydroxyl groups. These hydroxyl groups then undergo condensation reactions with hydroxyl groups on the surface of inorganic materials, forming strong chemical bonds. Secondly, the γ (organic functional group) can form a physically entangled, interpenetrating network system with the polymeric antistatic agent, thus forming strong chemical bonds. This invention, through the synergistic effect of hexagonal sheet magnesium hydroxide, silane coupling agent, inorganic hypophosphite flame retardant, and polymeric antistatic agent, prepares a polypropylene composite material that simultaneously satisfies the requirements of flame retardancy, antistatic properties, chemical resistance, and maintaining a good appearance.

[0009] Preferably, the polypropylene composite material comprises the following components in parts by weight: 30-45 parts PP resin, 30-35 parts hexagonal flake magnesium hydroxide, 0.3-0.5 parts silane coupling agent, 8-12 parts inorganic hypophosphite flame retardant, 12-18 parts polymeric antistatic agent, 2-4 parts interface compatibilizer, and 0.2-0.5 parts processing aid.

[0010] Optionally, the PP resin is in the range of 25 parts, 30 parts, 35 parts, 40 parts, 45 parts, and 50 parts by weight, or any two of these values; the hexagonal flake magnesium hydroxide is in the range of 25 parts, 30 parts, 35 parts, and 40 parts by weight, or any two of these values; the silane coupling agent is in the range of 0.1 parts, 0.3 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, and 1.0 parts by weight, or any two of these values; and the inorganic hypophosphite flame retardant is in the range of 5 parts, 6 parts, or any two of these values. The weight parts of the polymeric antistatic agent are 10, 12, 15, or any two of the following: 6.5 parts, 7 parts, 7.5 parts, 8 parts, 8.5 parts, 9 parts, 9.5 parts, 10 parts, 12 parts, and 15 parts; the weight parts of the interface compatibilizer are 1, 2, 3, and 5 parts; and the weight parts of the processing aid are 0, 0.1, 0.2, 0.3, and 0.5 parts.

[0011] Preferably, the silane coupling agent is at least one selected from 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, 3-glycidyl etheroxypropyltrimethoxysilane, 3-glycidyl etheroxypropyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropyltriethoxysilane, and 2-methacryloyloxymethyldimethoxysilane.

[0012] More preferably, the silane coupling agent is at least one selected from 3-methacryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropyltriethoxysilane, and 2-methacryloyloxymethyldimethoxysilane.

[0013] Preferably, the polypropylene composite material includes at least one of the following (1)-(4): (1) The melt flow rate of the PP resin at 230℃ / 2.16kg load is 25-60g / 10min according to ISO 1133-2011; (2) The inorganic hypophosphite flame retardant includes at least one of aluminum hypophosphite, calcium hypophosphite, and magnesium hypophosphite; (3) The interface compatibilizer is maleic anhydride-grafted polypropylene; and / or, the grafting rate of the maleic anhydride-grafted polypropylene is 0.8%-1.6%; (4) The processing aid is at least one of antioxidants and lubricants.

[0014] Optionally, the PP resin has a melt flow rate of 25 g / 10 min, 30 g / 10 min, 35 g / 10 min, 40 g / 10 min, 45 g / 10 min, 48 g / 10 min, 50 g / 10 min, or 60 g / 10 min, according to ISO 1133-2011 at 230°C / 2.16 kg load, based on any one or both of these ranges.

[0015] Optionally, the polyetheramide antistatic agent may comprise hard segments and soft segments, wherein the soft segments are formed by OH groups. - or NH2 - The functionalized polyether segments, with hard segments including one or more of PA6, PA66, PA6 / 66, PA610, PA612, PA614 and PA616, are connected to the polyamide segments by amide bonds to form a block polymer of the two.

[0016] Optionally, the weight-average molecular weight of the polyether amide antistatic agent is within the range of one or both of the following: 1000 g / mol, 10000 g / mol, 50000 g / mol, 150000 g / mol, 300000 g / mol, 335000 g / mol, 340000 g / mol, and 350000 g / mol; for example, the weight-average molecular weight of the polyether amide antistatic agent is optionally between 1000 g / mol and 350000 g / mol. When this condition is met, a polypropylene composite material that simultaneously satisfies flame retardancy, antistatic properties, chemical resistance, and maintains a good appearance can be prepared.

[0017] Optionally, the grafting rate of the maleic anhydride-grafted polypropylene is a value within the range of one or any two of 0.8%, 0.9%, 1.0%, 1.2%, 1.4%, and 1.6%. Optionally, the grafting rate of the maleic anhydride-grafted polypropylene is determined by acid-base titration.

[0018] Optionally, the processing aids include 0-0.3 parts of antioxidant and 0-0.3 parts of lubricant.

[0019] Optionally, the antioxidant is at least one of hindered phenolic antioxidants, hindered amine antioxidants, and phosphite antioxidants. Specifically, the antioxidant includes, but is not limited to, at least one of tris[2,4-di-tert-butylphenyl]phosphite (antioxidant 168), pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010), and phosphite antioxidants.

[0020] Optionally, the lubricant is at least one of stearic acid, stearate, and organosilicon compounds; such as pentaerythritol stearate, zinc stearate, etc.

[0021] Preferably, the particle size D50 of the hexagonal flake magnesium hydroxide is 0.5-5 μm, and the ratio of the side length to the thickness of the hexagonal flake magnesium hydroxide is (3-8):1.

[0022] Optionally, the magnesium hydroxide is in the form of hexagonal flakes, the side length of the magnesium hydroxide is the average side length of the hexagonal flake magnesium hydroxide, and the thickness of the magnesium hydroxide is the average thickness of the hexagonal flake magnesium hydroxide.

[0023] Optionally, the particle size D50 of the hexagonal flake magnesium hydroxide is measured by a laser particle size analyzer; the thickness and side length of the hexagonal flake magnesium hydroxide are observed by scanning electron microscopy, and 50 magnesium hydroxide particles are randomly selected to test the average value of the thickness and side length.

[0024] Furthermore, the present invention provides a method for preparing the aforementioned polypropylene composite material, comprising the following steps: (1) Weigh each component according to its weight parts; (2) Dissolve the silane coupling agent and add it to magnesium hydroxide. After mixing evenly, separate and dry to obtain the modified magnesium hydroxide. (3) Mix the components and the modified magnesium hydroxide prepared in step (2) and add them to an extruder for melt dispersion, melt mixing, extrusion granulation, and obtain the polypropylene composite material.

[0025] Optionally, in step (2), the specific method for dissolving the silane coupling agent is as follows: Prepare a mixed solution by mixing ethanol (or methanol) and deionized water at a volume ratio of 80:20 to 95:5. Adjust the pH of the mixed solution to a weakly acidic environment of 3.5-5.5 with acetic acid, stir and slowly add the silane coupling agent dropwise, and stir at 60°C for 30 min to 2 h to dissolve the silane coupling agent.

[0026] Optionally, in step (2), the product is washed with ethanol 1-2 times and dried at 100-120℃ for 4-6 hours.

[0027] Optionally, the extruder is a twin-screw extruder, the melt mixing temperature is 180-200℃, the screw speed is 350-450 rpm, and the screw length-to-diameter ratio is 40-56:1.

[0028] Furthermore, this invention provides applications of the aforementioned polypropylene composite material in the fields of new energy vehicles and electronic appliances. Further, this invention provides the use of the aforementioned polypropylene composite material in the manufacture of electronic device housings, control boxes, and battery boxes.

[0029] Compared to existing technologies, the beneficial effects of this invention are as follows: The selection of the silane coupling agent with a specific structure in this invention, on the one hand, allows its OR (hydrolyzable group) to react with residual water on the surface of magnesium hydroxide, hydrolyzing it into hydroxyl groups. These hydroxyl groups then undergo condensation reactions with hydroxyl groups on the surface of inorganic materials, forming strong chemical bonds. On the other hand, the γ (organic functional group) can form a physically entangled, interpenetrating network system with the polymeric antistatic agent, thus forming strong chemical bonds. This invention, through the synergistic effect of components such as magnesium hydroxide, silane coupling agent, inorganic hypophosphite flame retardant, and polymeric antistatic agent, prepares a polypropylene composite material that simultaneously satisfies the requirements of flame retardancy, antistatic properties, chemical resistance, and maintaining a good appearance. Detailed Implementation

[0030] To better illustrate the purpose, technical solution, and advantages of this invention, the invention will be further described below with reference to specific embodiments. The purpose is to provide a detailed understanding of the invention, not to limit it. All other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention. Unless otherwise specified, the experimental reagents and instruments designed in the embodiments and comparative examples of this invention are commonly used reagents and instruments, all of which are commercially available. Unless otherwise specified, the experimental methods used in the embodiments and comparative examples are conventional methods; and unless otherwise specified, the raw materials used in parallel experiments are from the same batch.

[0031] The raw materials used in the embodiments and comparative examples are described below, but are not limited to these materials: PP-1: PP PPH-Y26 (ZHONGKE), melt flow rate of 25 g / 10 min (230℃ / 2.16 kg), China Petroleum & Chemical Corporation Sales Co., Ltd. PP-2: PP 7555KNE2, melt flow rate of 50g / 10min (230℃ / 2.16kg), Exxonmobil Chemical Asia Pacific; PP-3: PPH MN60 (BEIHAI), melt mass flow rate of 60 g / 10 min (230℃ / 2.16 kg), Sinopec Beihai Refining & Chemical Co., Ltd. Magnesium hydroxide-1: Hexagonal flakes, particle size D50 2.2-2.5μm, side length / thickness 7.2; Magnesium hydroxide-2: Hexagonal flakes, particle size D50 0.5-0.8μm, side length / thickness 3.2; Magnesium hydroxide-3: hexagonal flakes, particle size D50 4.5μm, side length / thickness 4.5; Magnesium hydroxide-4: Irregular spherical shape, particle size D50 8μm.

[0032] Silane Coupling Agent-1: CAS: 2530-85-0, 3-Methacryloxypropyltrimethoxysilane, commercially available; Silane Coupling Agent-2: CAS: 13822-56-5, 3-aminopropyltrimethoxysilane, commercially available; Silane Coupling Agent-3: CAS: 2530-83-8, 3-glycidyl etheroxypropyltrimethoxysilane, commercially available; Silane Coupling Agent-4: CAS: 1067-25-0, n-propyltrimethoxysilane, commercially available; Silane Coupling Agent-5: CAS: 2996-92-1, Phenylacetyltrimethoxysilane, commercially available; Inorganic hypophosphite flame retardant-1: Aluminum hypophosphite, commercially available; Inorganic hypophosphite flame retardant-2: Magnesium hypophosphite, commercially available; Polymer-type antistatic agent-1: Polyether amide antistatic agent, PELESTAT-6500, Toyota Tsusho (Guangzhou) Co., Ltd.; Polymer-type antistatic agent-2: Polyether amide antistatic agent, AS5502P, Cangzhou Xuyang Chemical Co., Ltd.; Polymer-type antistatic agent-3: Polyether olefin antistatic agent, PELESTAT-230, Sanyo Chemicals; Interface compatibilizer-1: Maleic anhydride grafted polypropylene, grafting rate 0.8%, PC-3, Chengdu Jinfeng; Interface compatibilizer-2: maleic anhydride-grafted polypropylene, grafting rate 1.6%, PP-KF-1, Sawgrass; The antioxidant is a compound of commercially available hindered phenolic antioxidant 1010 and commercially available phosphite antioxidant 168 in a mass ratio of 1:1; Lubricant: Ester-based lubricant TR044W, commercially available.

[0033] Examples and Comparative Examples The polypropylene composite material of the present invention has the following composition as shown in Tables 1 and 2. The preparation method of the polypropylene composite material includes the following steps: (1) Weigh each component according to its weight parts; (2) The silane coupling agent was dissolved and added to magnesium hydroxide. After mixing evenly, the mixture was separated and dried to obtain the modified magnesium hydroxide. The specific method for dissolving the silane coupling agent is as follows: A mixed solution was prepared by mixing ethanol and deionized water at a volume ratio of 80:20. The pH value of the mixed solution was adjusted to a weakly acidic environment of 3.5-5.5 with acetic acid. The silane coupling agent was added slowly with stirring. The mixture was stirred at 60°C for 30 min to dissolve the silane coupling agent. The separation was performed by washing twice with ethanol and drying at 100°C for 4 h.

[0034] (3) Mix the components and the modified magnesium hydroxide prepared in step (2) and add them to an extruder for melt dispersion, melt mixing, extrusion granulation, and obtain the polypropylene composite material.

[0035] The conditions for melt extrusion of the extruder are as follows: Zone 1: 180℃, Zone 2: 180℃, Zone 3: 190℃, Zone 4: 190℃, Zone 5: 190℃, Zone 6: 190℃, Zone 7: 200℃, Zone 8: 200℃, the screw length-to-diameter ratio is 48:1, and the screw speed is 450 rpm.

[0036] Performance testing (1) Flame retardancy: Vertical burning test was conducted according to UL94-2022 standard, and the thickness of the test strip was 1.6 mm; (2) Surface resistance / Ω: According to IEC 60093-1980 standard, the surface resistance of a 100mm*100mm square plate was tested at 100V. (3) Chemical resistance: ISO tensile specimens were immersed in 1 mol / L hydrochloric acid solution for 168 h, and the tensile strength before and after immersion was tested. The performance retention rate was calculated as: tensile strength after immersion / tensile strength before immersion * 100%; (4) Evaluation of white spots in appearance: For injection-molded 100mm*100mm square plates, within 0.2m... 2 The area is graded according to the number of white dots of different diameters; Level 1: The number of white spots smaller than 0.15mm is not controlled; 0.15-0.25mm ≤ 1; 0.25-0.4mm ≤ 0; and larger than 0.4mm ≤ 0. Level 2: The number of white spots smaller than 0.15mm is not controlled; 0.15-0.25mm ≤ 4; 0.25-0.4mm ≤ 1; and larger than 0.4mm ≤ 0. Level 3: The number of white spots smaller than 0.15mm is not controlled; 0.15-0.25mm ≤ 8; 0.25-0.4mm ≤ 8; larger than 0.4mm ≤ 0. Level 4: The number of white spots smaller than 0.15mm is not controlled; the number of white spots between 0.15-0.25mm is not controlled; the number of white spots between 0.25-0.4mm is not controlled; and the number of white spots larger than 0.4mm is ≤4. Table 1 Table 2 As shown in the table above, the polypropylene composite material prepared in the embodiments of the present invention possesses excellent properties such as flame retardancy, antistatic properties, chemical resistance, and good appearance. It has a flame retardancy rating of V-0 and a surface resistivity ≤10×10⁻⁶. 9Ω, chemical resistance ≥90%, appearance grade 1.

[0037] As can be seen from the comparison of Examples 1-3, the polypropylene composite material prepared by the PP resin according to ISO 1133-2011 at a melt flow rate of 25-60 g / 10 min under 230℃ / 2.16 kg load has excellent properties such as flame retardancy, antistatic properties, chemical resistance and good appearance.

[0038] As can be seen from the comparison of Examples 1 and 4-5, the polypropylene composite material prepared by the silane coupling agent with the specific structural formula selected in this invention possesses excellent properties such as flame retardancy, antistatic properties, chemical resistance, and good appearance. On one hand, the silane coupling agent of this invention has a hydrolyzable OR group that can react with residual water on the surface of magnesium hydroxide, hydrolyzing it into hydroxyl groups. These hydroxyl groups then undergo a condensation reaction with hydroxyl groups on the surface of inorganic materials, forming strong chemical bonds. On the other hand, the Y organic functional group can form a physically entangled, interpenetrating network system with the polymeric antistatic agent, thus forming strong chemical bonds. When Y in the structural formula of the silane coupling agent is methacryloyloxy, the antistatic and chemical resistance are better because the methacryloyloxy group in the silane coupling agent bonds with the surface of magnesium hydroxide, resulting in the filler surface being covered with carbon-carbon double bonds. The antistatic agent molecule containing amide bonds itself has polymerizable double bonds. Under the action of heat and shear force during processing, the two undergo a free radical copolymerization reaction, forming covalent bonds. Magnesium hydroxide is coated with both silane coupling agent and antistatic agent, resulting in better chemical resistance. The synergistic effect between the antistatic agent and magnesium hydroxide further enhances the antistatic properties.

[0039] As can be seen from the comparison of Examples 1 and Examples 6-8, the antistatic and chemical resistance are better when the weight parts of each component meet the following: 30-45 parts of PP resin, 30-35 parts of magnesium hydroxide, 0.3-0.5 parts of silane coupling agent, 8-12 parts of inorganic hypophosphite flame retardant, 12-18 parts of polymeric antistatic agent, 2-4 parts of interface compatibilizer, and 0.2-0.5 parts of processing aid.

[0040] As can be seen from the comparison of Examples 1 and 9-10, when the particle size D50 of the hexagonal flake magnesium hydroxide is 0.5-5μm and the ratio of the side length to the thickness of the hexagonal flake magnesium hydroxide is (3-8):1, the prepared polypropylene composite material has excellent properties such as flame retardancy, antistatic properties, chemical resistance and good appearance.

[0041] As can be seen from the comparison between Example 1 and Comparative Example 1, when polyether olefin antistatic agents are selected, it is more difficult to build a conductive network under the same content, resulting in a worse antistatic effect.

[0042] As can be seen from the comparison of Example 1, Comparative Example 2, and Comparative Examples 5-6, when the system does not contain a silane coupling agent, the dispersibility of magnesium hydroxide and the antistatic agent is poor. Furthermore, the magnesium hydroxide has not undergone surface modification and is not protected by the silane coupling agent, resulting in insufficient flame retardancy, antistatic properties, chemical resistance, and appearance. When the silane coupling agent specific to this invention is not used, such as the n-propyltrimethoxysilane used in Comparative Example 5 and the phenyltrimethoxysilane used in Comparative Example 6, the end groups are non-polar functional groups, which do not interact with the antistatic agent, resulting in poor antistatic and chemical resistance.

[0043] As can be seen from the comparison between Example 1 and Comparative Example 3, when the system does not contain an antistatic agent, the surface resistivity is as high as 7.3 × 10⁻⁶. 15 Ω does not have good antistatic properties or chemical resistance.

[0044] As can be seen from the comparison of Example 1 and Comparative Example 4, when the silane coupling agent in the system is in excess, the oligomers will coat the surface of the filler particles like "glue," shielding the active functional groups and preventing them from reacting effectively with the polymeric antistatic agent, thus causing the "anchoring effect" to fail. During processing or use, these physically adsorbed silane molecules are prone to migrate and precipitate onto the material surface or interface, causing interface defects, and failing to meet the requirements for flame retardancy, antistatic properties, chemical resistance, and appearance.

[0045] As can be seen from the comparison of Example 1 and Comparative Example 5, when the hexagonal flake magnesium hydroxide of the present invention is not used, the particle size is larger, the specific surface area is smaller, the reaction sites are reduced, the magnesium hydroxide cannot be coated by silane coupling agent and antistatic agent, and the antistatic and chemical resistance properties are poor.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A polypropylene composite material, characterized in that, The product comprises the following components in parts by weight: 25-50 parts PP resin, 25-40 parts hexagonal flake magnesium hydroxide, 0.1-1.0 parts silane coupling agent, 5-15 parts inorganic hypophosphite flame retardant, 10-20 parts polymeric antistatic agent, 1-5 parts interface compatibilizer, and 0-0.5 parts processing aid; the silane coupling agent has the structural formula Y(CH2)nSi(OR)3, where OR is one of methoxy or ethoxy, Y is one of amino, epoxy, or methacryloxy, and n=1-4; the polymeric antistatic agent is at least one of polyether amide antistatic agent and polyether ester amide antistatic agent.

2. The polypropylene composite material as described in claim 1, characterized in that, It includes the following components in parts by weight: 30-45 parts PP resin, 30-35 parts hexagonal flake magnesium hydroxide, 0.3-0.5 parts silane coupling agent, 8-12 parts inorganic hypophosphite flame retardant, 12-18 parts polymeric antistatic agent, 2-4 parts interface compatibilizer, and 0.2-0.5 parts processing aid.

3. The polypropylene composite material as described in claim 1, characterized in that, The silane coupling agent is at least one of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, 3-glycidyl etheroxypropyltrimethoxysilane, 3-glycidyl etheroxypropyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropyltriethoxysilane, and 2-methacryloyloxymethyldimethoxysilane.

4. The polypropylene composite material as described in claim 1, characterized in that, Includes at least one of the following (1)-(4): (1) The melt flow rate of the PP resin at 230℃ / 2.16kg load is 25-60g / 10min according to ISO 1133-2011; (2) The inorganic hypophosphite flame retardant includes at least one of aluminum hypophosphite, calcium hypophosphite, and magnesium hypophosphite; (3) The interface compatibilizer is maleic anhydride-grafted polypropylene; and / or, the grafting rate of the maleic anhydride-grafted polypropylene is 0.8%-1.6%; (4) The processing aid is at least one of antioxidants and lubricants.

5. The polypropylene composite material as described in claim 1, characterized in that, The particle size D50 of the hexagonal flake magnesium hydroxide is 0.5-5 μm, and the ratio of the side length to the thickness of the hexagonal flake magnesium hydroxide is (3-8):

1.

6. A method for preparing a polypropylene composite material according to any one of claims 1-5, characterized in that, Includes the following steps: (1) Weigh each component according to its weight parts; (2) Dissolve the silane coupling agent and add it to magnesium hydroxide. After mixing evenly, separate and dry to obtain the modified magnesium hydroxide. (3) Mix the components and the modified magnesium hydroxide prepared in step (2) and add them to an extruder for melt dispersion, melt mixing, extrusion granulation, and obtain the polypropylene composite material.

7. The application of a polypropylene composite material as described in any one of claims 1-5 in the fields of new energy vehicles and electronic appliances.

8. The application as described in claim 7, characterized in that, The polypropylene composite material according to any one of claims 1-5 is used to manufacture electronic device housings, control boxes, and battery boxes.

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