High-conductivity and high-thermal-conductivity polypropylene composite material and preparation method thereof

Abstract

The invention discloses a high-conductivity and high-heat-conductivity polypropylene composite material and a preparation method thereof. The high-conductivity and high-thermal-conductivity polypropylene composite material is prepared from the following raw materials in percentage by weight: 40 to 80 percent of polypropylene resin (PP), 1 to 10 percent of carbon nanostructure material CNS, 5 to 40 percent of boron nitride, 5 to 40 percent of magnesium oxide, 0.1 to 30 percent of talcum powder, 0.5 to 10 percent of compatilizer, 0.1 to 5 percent of silane coupling agent, 0.1 to 15 percent of flexibilizer, 0.1 to 5 percent of antioxidant and 0 to 2 percent of other auxiliaries. The high-conductivity and high-thermal-conductivity polypropylene composite material disclosed by the invention has relatively high mechanical properties, excellent conductivity, relatively high thermal conductivity and excellent injection molding performance, and can be widely applied to the fields of automobile industry, electronic appliances and electronic packaging.

Description

Technical Field

[0001] This invention relates to a highly conductive and highly thermally conductive polypropylene composite material and its preparation method, which can be applied in the automotive industry, electronics and electrical appliances and electronic packaging fields, and belongs to the field of polymer material processing and modification technology. Background Technology

[0002] Polypropylene (PP) is a general-purpose plastic with excellent overall performance. It boasts advantages such as light weight, good heat resistance, low price, non-toxicity, good corrosion resistance, excellent electrical insulation, and good processability, making it widely applicable in the automotive industry, electronics, packaging, building materials, furniture, and medical fields. However, polypropylene itself is an insulating material with a low thermal conductivity of approximately 0.2 W / (m²). · K), high surface resistivity (>10 K), 15 The current Ω / sq content cannot meet the requirements of modern electronics industry for heat dissipation and electrical conductivity, which limits the further expansion of the application range of polypropylene materials. Currently, research has focused on improving the performance of polypropylene materials by adding conductive fillers (such as carbon black, carbon nanotubes, carbon fibers, graphite, metal powders, and metal fibers) or thermally conductive fillers (such as magnesium oxide, aluminum oxide, boron nitride, and aluminum nitride). There are also related studies on multi-component filler systems (such as carbon black / carbon nanotube synergistic systems). However, existing technologies still have some typical problems: ① poor filler dispersibility and easy agglomeration; ② competition between conductive and thermally conductive networks, making it difficult to form a synergistic effect; ③ poor interfacial compatibility between the filler and the matrix resin, with high filler addition leading to a decrease in the material's mechanical properties. Chinese patent CN108929587 A discloses a thermally conductive and electromagnetically shielding polypropylene composite material and its preparation method. The method involves adding one or more of magnesium oxide, aluminum oxide, zinc oxide, aluminum nitride, boron nitride, and silicon carbide to impart thermal conductivity to polypropylene, while using one of nanoscale carbon nanotubes, nanoscale graphene, and carbon fibers as a conductive agent to obtain a polypropylene composite material with high thermal conductivity and electromagnetic shielding performance. However, this invention uses a high amount of conventional thermally conductive agent and does not consider the synergistic effect of thermal and electrical conductivity, resulting in a decrease in the mechanical properties of the final product, especially a very low flexural modulus. Therefore, developing a polypropylene composite material that combines high electrical conductivity, high thermal conductivity, and good mechanical properties has significant industrial application value. Summary of the Invention

[0003] The purpose of this invention is to provide a high electrical and thermal conductivity polypropylene composite material and its preparation method, so as to overcome the shortcomings of the prior art.

[0004] The technical solution of the present invention is as follows:

[0005] A highly conductive and highly thermally conductive polypropylene composite material, formulated by weight percentage from the following raw materials:

[0006] Polypropylene resin (PP) 40-80%,

[0007] Carbon nanostructured materials CNS1-10%,

[0008] Boron nitride 5-40%,

[0009] Magnesium oxide 5-40%,

[0010] Talc powder 0.1-30%,

[0011] Compatibilizer 0.5-10%,

[0012] Silane coupling agent 0.1-5%,

[0013] Toughening agent 0.1-15%,

[0014] Antioxidant 0.1-5%,

[0015] Other additives: 0-2%.

[0016] The polypropylene resin (PP) is a mixture of one or more of copolymer polypropylene and homopolymer polypropylene, and its melt index is between 1 and 100 g / 10 min under test conditions of 230°C and 2.16 kg.

[0017] The carbon nanostructure material CNS is an array-distributed multi-walled carbon nanotube material with a unique branched structure. Unlike traditional multi-walled carbon nanotubes (CNTs), it has a unique branched structure and better dispersibility, with a carbon content >97% and a specific surface area >200㎡ / g.

[0018] The boron nitride particles have a particle size between 10 and 40 μm and a purity > 99.5%.

[0019] The magnesium oxide particles have a particle size between 0.1 μm and 2 μm and a purity > 99.5%.

[0020] The talc powder has a particle size between 2 and 10 μm.

[0021] The compatibilizer is maleic anhydride-grafted polypropylene (PP-g-MAH), with a grafting rate of 1.5%.

[0022] The toughening agent is an ethylene / octene copolymer (POE), which, under test conditions of 190°C and 2.16 kg, has a melt index between 0.5 and 30 g / 10 min and a density between 0.86 and 0.92 g / cm³. 3 between.

[0023] The silane coupling agent is one or a mixture of several of KH-550, KH-560 and KH-570.

[0024] The antioxidants mentioned include primary antioxidants and secondary antioxidants. The primary antioxidants are hindered phenols or thioester antioxidants; the secondary antioxidants are phosphites or ester antioxidants.

[0025] The primary antioxidant is one or more of diethyl 3,5-di-tert-butyl-4-hydroxybenzyl phosphate (3114), pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (1010), and octadecyl thiodipropionate (DSTP); the secondary antioxidant is one or more of pentaerythritol distearate diphosphite (618), tris(2,4-di-tert-butylphenyl) phosphite (168), and pentaerythritol distearate diphosphite (619F).

[0026] The preparation method of the high electrical and thermal conductivity polypropylene composite material comprises the following steps:

[0027] (1) Weigh out polypropylene resin (PP), talc, compatibilizer, toughening agent, antioxidant and other additives according to the above proportions, and mix them in a high-speed mixer for 2 to 5 minutes.

[0028] (2) Weigh carbon nanostructure material CNS, boron nitride, magnesium oxide and silane coupling agent according to the above proportions, and mix them in a high-speed mixer for 2 to 5 minutes to obtain a conductive and thermally conductive composite filler.

[0029] (3) Add the uniform mixture from step (1) into the main feeder of the twin-screw extruder, and at the same time add the conductive and thermally conductive composite filler corresponding to step (2) into the side feeder. After the main feed material melts, it is melt-blended with the material entering from the side feed port, and then extruded and granulated. The temperatures of each section of the extruder are as follows: Zone 1 90~100℃, Zone 2 150~160℃, Zone 3 220~230℃, Zone 4 220~230℃, Zone 5 220~230℃, Zone 6 220~230℃, Zone 7 210~220℃, Zone 8 210~220℃, Zone 9 210~220℃, Zone 10 210~220℃, and the main machine speed is 500~600rpm.

[0030] This invention provides a long-range conductive path through a novel carbon nanostructure material (CNS), and constructs an efficient thermally conductive channel using boron nitride / magnesium oxide. The two are bridged by a silane coupling agent to form an interpenetrating network, thereby endowing the polypropylene composite material with excellent electrical and thermal conductivity while maintaining high mechanical properties. Detailed Implementation

[0031] The present invention can be further described through the following preferred embodiments, but these embodiments are only illustrative and do not define the scope of the present invention.

[0032] The main raw materials used in the embodiments and comparative examples of this invention are as follows:

[0033] Polypropylene resin (PP): PP BX3900, ExxonMobil;

[0034] Polypropylene resin (PP): PP SP179, LyondellBasell;

[0035] Carbon nanostructure materials CNS: ATHLOS TM CNS, Cabot;

[0036] Boron nitride: BN-SS, Liaobin Fine Chemical Co., Ltd.;

[0037] Magnesium oxide: Kyowamag MF-150, Kyowa Chemical Industry Co., Ltd.;

[0038] Talc: Steamic T1CN, Imerys;

[0039] Compatibilizer: Maleic anhydride-grafted polypropylene (PP-g-MAH), Huawen Chemical;

[0040] Silane coupling agent: KH-550, Boiling Point New Materials Co., Ltd.

[0041] Toughening agent: POE-7467, Dow Chemical, USA;

[0042] Main antioxidant: 1010, BASF, Germany;

[0043] Co-oxidant: 168, Saint-Lecott;

[0044] Carbon black: M800, Cabot;

[0045] Multi-walled carbon nanotubes: LUCAN BT1001M, LG Chem.

[0046] Example 1

[0047] 19.7 parts of polypropylene resin PP BX3900, 14 parts of polypropylene resin PP SP179, 20 parts of talc powder SteamicT1CN, 2 parts of compatibilizer maleic anhydride grafted polypropylene, 7 parts of toughening agent POE-7467, 0.1 parts of primary antioxidant 1010, 0.2 parts of auxiliary antioxidant 168, and 0.5 parts of carbon black m800 were added to a high-speed mixer and mixed for 2-5 minutes. After uniform mixing, the mixture was added to the main feeder of a twin-screw extruder. Simultaneously, 1 part of carbon nanostructure material CNS, 20 parts of boron nitride BN-SS, 15 parts of magnesium oxide MF-150, and 0.5 parts of silane coupling agent KH-550 were weighed and added to the high-speed mixer and mixed for 2-5 minutes to obtain a conductive and thermally conductive composite filler, which was then added to a side feeder. After the main feeder material melted, it was melt-blended with the material entering through the side feeder, extruded, and granulated to obtain a high-conductivity and high-thermal-conductivity polypropylene composite material.

[0048] The temperatures of each section of the extruder are as follows: Zone 1 90-100℃, Zone 2 150-160℃, Zone 3 220-230℃, Zone 4 220-230℃, Zone 5 220-230℃, Zone 6 220-230℃, Zone 7 210-220℃, Zone 8 210-220℃, Zone 9 210-220℃, Zone 10 210-220℃, and the main extruder speed is 500-600 rpm.

[0049] Example 2

[0050] 18.7 parts of polypropylene resin PP BX3900, 14 parts of polypropylene resin PP SP179, 20 parts of talc powder SteamicT1CN, 2 parts of compatibilizer maleic anhydride grafted polypropylene, 7 parts of toughening agent POE-7467, 0.1 parts of primary antioxidant 1010, 0.2 parts of auxiliary antioxidant 168, and 0.5 parts of carbon black m800 were added to a high-speed mixer and mixed for 2-5 minutes. After uniform mixing, the mixture was added to the main feeder of a twin-screw extruder. Simultaneously, 2 parts of carbon nanostructure material CNS, 20 parts of boron nitride BN-SS, 15 parts of magnesium oxide MF-150, and 0.5 parts of silane coupling agent KH-550 were weighed and added to the high-speed mixer and mixed for 2-5 minutes to obtain a conductive and thermally conductive composite filler, which was then added to a side feeder. After the main feed material melted, it was melt-blended with the material entering through the side feeder, extruded, and granulated to obtain a high-conductivity and high-thermal-conductivity polypropylene composite material.

[0051] The temperatures of each section of the extruder are as follows: Zone 1 90-100℃, Zone 2 150-160℃, Zone 3 220-230℃, Zone 4 220-230℃, Zone 5 220-230℃, Zone 6 220-230℃, Zone 7 210-220℃, Zone 8 210-220℃, Zone 9 210-220℃, Zone 10 210-220℃, and the main extruder speed is 500-600 rpm.

[0052] Example 3

[0053] 17.7 parts of polypropylene resin PP BX3900, 14 parts of polypropylene resin PP SP179, 20 parts of talc powder SteamicT1CN, 2 parts of compatibilizer maleic anhydride grafted polypropylene, 7 parts of toughening agent POE-7467, 0.1 parts of primary antioxidant 1010, 0.2 parts of auxiliary antioxidant 168, and 0.5 parts of carbon black m800 were added to a high-speed mixer and mixed for 2-5 minutes. After uniform mixing, the mixture was added to the main feeder of a twin-screw extruder. Simultaneously, 3 parts of carbon nanostructure material CNS, 20 parts of boron nitride BN-SS, 15 parts of magnesium oxide MF-150, and 0.5 parts of silane coupling agent KH-550 were weighed and added to the high-speed mixer and mixed for 2-5 minutes to obtain a conductive and thermally conductive composite filler, which was then added to a side feeder. After the main feeder material melted, it was melt-blended with the material entering through the side feeder, extruded, and granulated to obtain a high-conductivity and high-thermal-conductivity polypropylene composite material.

[0054] The temperatures of each section of the extruder are as follows: Zone 1 90-100℃, Zone 2 150-160℃, Zone 3 220-230℃, Zone 4 220-230℃, Zone 5 220-230℃, Zone 6 220-230℃, Zone 7 210-220℃, Zone 8 210-220℃, Zone 9 210-220℃, Zone 10 210-220℃, and the main extruder speed is 500-600 rpm.

[0055] Example 4

[0056] 16.7 parts of polypropylene resin PP BX3900, 14 parts of polypropylene resin PP SP179, 20 parts of talc powder SteamicT1CN, 2 parts of compatibilizer maleic anhydride grafted polypropylene, 7 parts of toughening agent POE-7467, 0.1 parts of primary antioxidant 1010, 0.2 parts of auxiliary antioxidant 168, and 0.5 parts of carbon black m800 were added to a high-speed mixer and mixed for 2-5 minutes. After uniform mixing, the mixture was added to the main feeder of a twin-screw extruder. Simultaneously, 4 parts of carbon nanostructure material CNS, 20 parts of boron nitride BN-SS, 15 parts of magnesium oxide MF-150, and 0.5 parts of silane coupling agent KH-550 were weighed and added to the high-speed mixer and mixed for 2-5 minutes to obtain a conductive and thermally conductive composite filler, which was then added to a side feeder. After the main feed material melted, it was melt-blended with the material entering through the side feeder, extruded, and granulated to obtain a high-conductivity and high-thermal-conductivity polypropylene composite material.

[0057] The temperatures of each section of the extruder are as follows: Zone 1 90-100℃, Zone 2 150-160℃, Zone 3 220-230℃, Zone 4 220-230℃, Zone 5 220-230℃, Zone 6 220-230℃, Zone 7 210-220℃, Zone 8 210-220℃, Zone 9 210-220℃, Zone 10 210-220℃, and the main extruder speed is 500-600 rpm.

[0058] Example 5

[0059] 17.7 parts of polypropylene resin PP BX3900, 14 parts of polypropylene resin PP SP179, 20 parts of talc powder SteamicT1CN, 2 parts of compatibilizer maleic anhydride grafted polypropylene, 7 parts of toughening agent POE-7467, 0.1 parts of primary antioxidant 1010, 0.2 parts of auxiliary antioxidant 168, and 0.5 parts of carbon black m800 were added to a high-speed mixer and mixed for 2-5 minutes. After uniform mixing, the mixture was added to the main feeder of a twin-screw extruder. Simultaneously, 3 parts of carbon nanostructure material CNS, 10 parts of boron nitride BN-SS, 25 parts of magnesium oxide MF-150, and 0.5 parts of silane coupling agent KH-550 were weighed and added to the high-speed mixer and mixed for 2-5 minutes to obtain a conductive and thermally conductive composite filler, which was then added to a side feeder. After the main feed material melted, it was melt-blended with the material entering through the side feeder, extruded, and granulated to obtain a high-conductivity and high-thermal-conductivity polypropylene composite material.

[0060] The temperatures of each section of the extruder are as follows: Zone 1 90-100℃, Zone 2 150-160℃, Zone 3 220-230℃, Zone 4 220-230℃, Zone 5 220-230℃, Zone 6 220-230℃, Zone 7 210-220℃, Zone 8 210-220℃, Zone 9 210-220℃, Zone 10 210-220℃, and the main extruder speed is 500-600 rpm.

[0061] Example 6

[0062] 17.7 parts of polypropylene resin PP BX3900, 14 parts of polypropylene resin PP SP179, 20 parts of talc powder SteamicT1CN, 2 parts of compatibilizer maleic anhydride grafted polypropylene, 7 parts of toughening agent POE-7467, 0.1 parts of primary antioxidant 1010, 0.2 parts of auxiliary antioxidant 168, and 0.5 parts of carbon black m800 were added to a high-speed mixer and mixed for 2-5 minutes. After uniform mixing, the mixture was added to the main feeder of a twin-screw extruder. Simultaneously, 3 parts of carbon nanostructure material CNS, 30 parts of boron nitride BN-SS, 5 parts of magnesium oxide MF-150, and 0.5 parts of silane coupling agent KH-550 were weighed and added to the high-speed mixer and mixed for 2-5 minutes to obtain a conductive and thermally conductive composite filler, which was then added to a side feeder. After the main feeder material melted, it was melt-blended with the material entering through the side feeder, extruded, and granulated to obtain a high-conductivity and high-thermal-conductivity polypropylene composite material.

[0063] The temperatures of each section of the extruder are as follows: Zone 1 90-100℃, Zone 2 150-160℃, Zone 3 220-230℃, Zone 4 220-230℃, Zone 5 220-230℃, Zone 6 220-230℃, Zone 7 210-220℃, Zone 8 210-220℃, Zone 9 210-220℃, Zone 10 210-220℃, and the main extruder speed is 500-600 rpm.

[0064] Comparative Example 1

[0065] 17.7 parts of polypropylene resin PP BX3900, 14 parts of polypropylene resin PP SP179, 20 parts of talc powder SteamicT1CN, 2 parts of compatibilizer maleic anhydride grafted polypropylene, 7 parts of toughening agent POE-7467, 0.1 parts of primary antioxidant 1010, 0.2 parts of auxiliary antioxidant 168, and 0.5 parts of carbon black m800 were added to a high-speed mixer and mixed for 2-5 minutes. After uniform mixing, the mixture was added to the main feeder of a twin-screw extruder. Simultaneously, 3 parts of carbon nanostructure material CNS, 35 parts of magnesium oxide MF-150, and 0.5 parts of silane coupling agent KH-550 were weighed and added to the high-speed mixer and mixed for 2-5 minutes to obtain a conductive and thermally conductive composite filler, which was then added to a side feeder. After the main feeder material melted, it was melt-blended with the material entering through the side feeder, extruded, and granulated to obtain a high-conductivity and high-thermal-conductivity polypropylene composite material.

[0066] The temperatures of each section of the extruder are as follows: Zone 1 90-100℃, Zone 2 150-160℃, Zone 3 220-230℃, Zone 4 220-230℃, Zone 5 220-230℃, Zone 6 220-230℃, Zone 7 210-220℃, Zone 8 210-220℃, Zone 9 210-220℃, Zone 10 210-220℃, and the main extruder speed is 500-600 rpm.

[0067] Comparative Example 2

[0068] 17.7 parts of polypropylene resin PP BX3900, 14 parts of polypropylene resin PP SP179, 20 parts of talc powder SteamicT1CN, 2 parts of compatibilizer maleic anhydride grafted polypropylene, 7 parts of toughening agent POE-7467, 0.1 parts of primary antioxidant 1010, 0.2 parts of auxiliary antioxidant 168, and 0.5 parts of carbon black m800 were added to a high-speed mixer and mixed for 2-5 minutes. After uniform mixing, the mixture was added to the main feeder of a twin-screw extruder. At the same time, 3 parts of multi-walled carbon nanotubes LUCAN BT1001M, 20 parts of boron nitride BN-SS, 15 parts of magnesium oxide MF-150, and 0.5 parts of silane coupling agent KH-550 were weighed and added to a high-speed mixer and mixed for 2-5 minutes to obtain a conductive and thermally conductive composite filler, which was then added to a side feeder. After the main feed material is melted, it is melt-blended with the material entering through the side feed port, and then extruded and granulated to obtain a polypropylene composite material with high electrical and thermal conductivity.

[0069] The temperatures of each section of the extruder are as follows: Zone 1 90-100℃, Zone 2 150-160℃, Zone 3 220-230℃, Zone 4 220-230℃, Zone 5 220-230℃, Zone 6 220-230℃, Zone 7 210-220℃, Zone 8 210-220℃, Zone 9 210-220℃, Zone 10 210-220℃, and the main extruder speed is 500-600 rpm.

[0070] Performance evaluation and implementation standards:

[0071] In the above embodiments and comparative examples, the performance of the products was tested according to the following standards and conditions.

[0072] Apparent density was tested according to ISO 1183-1; flexural strength and flexural modulus were tested according to ISO 178, with a specimen size of 80×10×4mm, a bending speed of 2mm / min, and a span of 64mm; tensile strength was tested according to ISO 527, with a type 1A specimen and a tensile speed of 50mm / min; notched impact strength of simply supported beams was tested according to ISO 179-1, with a specimen size of 80×10×4mm, a type A notch, and a test temperature of 23℃; surface resistivity was tested according to ASTM D257; and thermal conductivity was tested according to GB / T 10295.

[0073] The test results of various physical properties of the products obtained in Examples 1-6 and Comparative Examples 1-2 are listed in Table 1.

[0074] Examples 1-4 show that as the amount of carbon nanostructured material (CNS) added increases, the surface resistivity of the polypropylene composite material continuously decreases. When the amount of CNS added is 4 wt%, the surface resistivity of the material can reach 10 Ω·cm. 3 The Ω / sq value was found to be high, and the addition of CNS improved the flexural strength, flexural modulus, and tensile strength of the material to some extent. Furthermore, it was observed that the conductive and thermally conductive fillers did not interfere with each other; in fact, they exhibited a synergistic effect. The thermal conductivity of the products in the examples was greater than 1 W / (m²). · K). Comparing Example 3 with Comparative Example 2, it can be found that, with the same amount added, carbon nanostructure material CNS has a much better electrical conductivity than conventional multi-walled carbon nanotube material CNT, and CNS is more likely to have a synergistic effect with thermally conductive fillers. With the same formulation, the thermal conductivity of the product with added CNS is significantly higher than that of the product with the same proportion of CNT.

[0075] Comparing Examples 3, 5, and 6 with Comparative Example 1, it can be seen that adding magnesium oxide as a single conductive filler results in a product with a lower thermal conductivity (<1 W / (m²)). · However, when boron nitride and magnesium oxide are used in combination, a synergistic effect occurs, making it easier to form a thermally conductive network in the material system. With the same total addition ratio, the thermal conductivity of the product obtained by using boron nitride and magnesium oxide in combination is greater than 1 W / (m²). · K).

[0076] This invention provides a polypropylene composite material with high electrical and thermal conductivity. This material not only has good mechanical properties, but also excellent electrical conductivity and high thermal conductivity, and can be applied in the automotive industry, electronics, electronic packaging and other fields.

[0077] Table 1. Physical properties of the corresponding products in the examples and comparative examples.

[0078]

[0079] The above embodiments are provided to better illustrate the specific content of the present invention, but the scope of protection of the present invention is not limited thereto. Any researcher skilled in the art can easily modify or replace these embodiments and apply the basic principles of the present invention to other embodiments without creative effort. Therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A polypropylene composite material with high electrical and thermal conductivity, characterized in that, It is formulated from the following raw materials by weight percentage: Polypropylene resin (PP) 40-80%, Carbon nanostructured materials CNS1-10%, Boron nitride 5-40%, Magnesium oxide 5-40%, Talc powder 0.1-30%, Compatibilizer 0.5-10%, Silane coupling agent 0.1-5%, Toughening agent 0.1-15%, Antioxidant 0.1-5%, Other additives: 0-2%.

2. The high electrical and thermal conductivity polypropylene composite material according to claim 1, characterized in that, The polypropylene resin (PP) is a mixture of one or more of copolymer polypropylene and homopolymer polypropylene, and its melt index is between 1 and 100 g / 10 min under test conditions of 230°C and 2.16 kg.

3. The high electrical and thermal conductivity polypropylene composite material according to claim 1, characterized in that, The carbon nanostructure material CNS is an array-distributed multi-walled carbon nanotube material with a unique branched structure. It has a unique branched structure and better dispersibility, with a carbon content of >97% and a specific surface area of ​​>200㎡ / g.

4. The high electrical and thermal conductivity polypropylene composite material according to claim 1, characterized in that, The boron nitride particles have a particle size between 10 and 40 μm and a purity > 99.5%.

5. The high electrical and thermal conductivity polypropylene composite material according to claim 1, characterized in that, The magnesium oxide particles have a particle size between 0.1 μm and 2 μm and a purity > 99.5%.

6. The high electrical and thermal conductivity polypropylene composite material according to claim 1, characterized in that, The talc powder has a particle size between 2 and 10 μm.

7. The high electrical and thermal conductivity polypropylene composite material according to claim 1, characterized in that, The compatibilizer is maleic anhydride-grafted polypropylene (PP-g-MAH), with a grafting rate of 1.5%.

8. The high electrical and thermal conductivity polypropylene composite material according to claim 1, characterized in that, The toughening agent is an ethylene / octene copolymer (POE), which, under test conditions of 190°C and 2.16 kg, has a melt index between 0.5 and 30 g / 10 min and a density between 0.86 and 0.92 g / cm³. 3 between.

9. The high electrical and thermal conductivity polypropylene composite material according to claim 1, characterized in that, The silane coupling agent is one or a mixture of several of KH-550, KH-560 and KH-570.

10. The high electrical and thermal conductivity polypropylene composite material according to claim 1, characterized in that, The antioxidants mentioned include primary antioxidants and secondary antioxidants. The primary antioxidants are hindered phenols or thioester antioxidants; the secondary antioxidants are phosphites or ester antioxidants.

11. The high electrical and thermal conductivity polypropylene composite material according to claim 10, characterized in that, The primary antioxidant is one or more of diethyl 3,5-di-tert-butyl-4-hydroxybenzyl phosphate (3114), pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (1010), and octadecyl thiodipropionate (DSTP); the secondary antioxidant is one or more of pentaerythritol distearate diphosphite (618), tris(2,4-di-tert-butylphenyl) phosphite (168), and pentaerythritol distearate diphosphite (619F).

12. The method for preparing the highly conductive and highly thermally conductive polypropylene composite material according to any one of claims 1-11, characterized in that... The steps are as follows: (1) Weigh out polypropylene resin (PP), talc, compatibilizer, toughening agent, antioxidant and other additives according to the above proportions, and mix them in a high-speed mixer for 2 to 5 minutes. (2) Weigh carbon nanostructure material CNS, boron nitride, magnesium oxide and silane coupling agent according to the above proportions, and mix them in a high-speed mixer for 2 to 5 minutes to obtain a conductive and thermally conductive composite filler. (3) Add the uniform mixture from step (1) into the main feeder of the twin-screw extruder, and at the same time add the conductive and thermally conductive composite filler corresponding to step (2) into the side feeder. After the main feed material melts, it is melt-blended with the material entering from the side feed port, and then extruded and granulated. The temperatures of each section of the extruder are as follows: Zone 1 90~100℃, Zone 2 150~160℃, Zone 3 220~230℃, Zone 4 220~230℃, Zone 5 220~230℃, Zone 6 220~230℃, Zone 7 210~220℃, Zone 8 210~220℃, Zone 9 210~220℃, Zone 10 210~220℃, and the main machine speed is 500~600rpm.

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