Polyolefin thermal management composite material as well as preparation method and application thereof

Abstract

The invention relates to a polyolefin thermal management composite material and a preparation method thereof. The polyolefin thermal management composite material is prepared from the following components in parts by weight: 60-74 parts of co-polypropylene, 25-40 parts of modified thermal management filler, 5-12 parts of a flexibilizer, 0.1-0.3 part of an antioxidant, 0.1-0.3 part of a lubricant and 0.1-0.5 part of a light stabilizer. The polyolefin radiation heat management composite material provided by the invention is improved in the aspects of mechanical property and heat management property, has better heat conduction efficiency, and is particularly improved in the aspects of reflectivity and emissivity.

Description

Technical Field

[0001] The present invention relates to the technical field of composite materials, and particularly relates to a polyolefin thermal management composite material and a preparation method thereof. Background Art

[0002] Polypropylene (PP) is one of the most widely used general-purpose polymer materials at present. Due to its stable chemical properties, excellent mechanical properties and outstanding processability, it is widely used in many fields such as automotive, aviation, medical and chemical industries. With its relatively high melting point and excellent electrical insulation, PP occupies an important position in these industries. However, polypropylene has deficiencies in thermal management, especially its low thermal conductivity (only 0.22 - 0.24 W·m -1 ·K -1 ), which limits its use in some high-demand application scenarios. Especially in the automotive industry, with the increasing demand for efficient thermal management, the thermal conductivity of traditional polypropylene can no longer meet the emerging needs.

[0003] Therefore, improving the thermal conductivity of polypropylene has become a key direction in the development of automotive materials. To solve this problem, the modification of polypropylene has become an inevitable trend. Among them, the method of filling and modifying with thermal conductive particles is currently the most economical, effective and widely used method. By adding thermal conductive particles to polypropylene, its thermal conductivity can be significantly improved, thus meeting the strict requirements for thermal management in the automotive industry.

[0004] Thermally modified polypropylene not only has excellent thermal conductivity, but also exhibits other outstanding advantages. Especially its excellent sunlight reflection ability and thermal radiation emission performance, which enable it to effectively reduce the heat load on the vehicle body surface, improve the energy efficiency of the vehicle air conditioning system, and extend the service life of interior components. In addition, the modified polypropylene material has higher thermal conductivity and good mechanical properties, so it has broad application prospects in automotive interior and exterior parts, roof, window frame, etc. It can effectively optimize the thermal management system of the vehicle and reduce the problems of aging and deformation of interior and exterior parts caused by overheating. At the same time, this material has good processability and adaptability, can meet the high-efficiency production requirements of modern automotive manufacturing, and further promotes the technological innovation of new energy vehicles and traditional fuel vehicles in thermal management. Summary of the Invention

[0005] Based on this, the purpose of the present invention is to provide a polyolefin thermal management composite material and a preparation method thereof. The polyolefin thermal management composite material product has good mechanical properties and good thermal conductivity, and can be applied to heat dissipation modules such as automotive lighting and communication.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions: The present invention first provides a polyolefin thermal management composite material, which is prepared from the following components in parts by weight: 60-74 parts of copolymerized polypropylene, 25-40 parts of modified thermal management filler, 5-12 parts of toughening agent, 0.1-0.3 parts of antioxidant, 0.1-0.3 parts of lubricant, and 0.1-0.5 parts of light stabilizer.

[0007] As a further improvement of the above solution of the present invention, the preparation method of the modified thermal management filler is as follows: boron nitride powder is added to a solvent and mixed, and after adding a surfactant, ultrasonic exfoliation treatment is carried out. The supernatant is taken by centrifugal separation and dried to obtain boron nitride nanosheets; the boron nitride nanosheets are dispersed in water, the pH is adjusted to alkaline, a chemical surface modifier is added, stirred, washed, and dried to obtain the modified thermal management filler.

[0008] As a further improvement of the above solution of the present invention, the solvent is one of deionized water, ethanol, isopropanol, and dichloromethane; and / or, the surfactant is one of sodium dodecylbenzenesulfonate, polyvinylpyrrolidone, and polyvinyl alcohol; and / or, the conditions of the ultrasonic exfoliation treatment are: power is 90-120W, frequency is 20-40Hz, time is 45-75min, and temperature is 35-45°C.

[0009] As a further improvement of the above solution of the present invention, adjusting the pH to alkaline is to add sodium bicarbonate to adjust the pH to 8-9; and / or, the chemical surface modifier is tannic acid; and / or, by mass, the addition amount of the chemical surface modifier is 10%-20% of boron nitride; and / or, the stirring is carried out at room temperature for 9-15h, and the drying is carried out at 70-90°C under normal pressure.

[0010] As a further improvement of the above solution of the present invention, the copolymerized polypropylene is one of Wuhan Petrochemical copolymerized PPK7227H, Zhong'an United copolymerized PP M30RH, SK Zhonghan Petrochemical copolymerized PP BX3800, and Lanzhou Petrochemical copolymerized PP EP533N.

[0011] As a further improvement of the above solution of the present invention, the toughening agent is one of ethylene-propylene-diene copolymer, styrene-butadiene-styrene triblock copolymer, and polystyrene-poly(ethylene-butene)-polystyrene block copolymer.

[0012] As a further improvement of the above solution of the present invention, the antioxidant is one of dipentaerythritol diisodecyl diphosphite, pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2,4-bis((dodecylthio)methyl)-6-methylphenol, octadecyl 3,5-bis(1,1-dimethylethyl)-4-hydroxyphenylpropionate, tris(2,4-di-tert-butylphenyl) phosphite, N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexanediamine.

[0013] As a further improvement of the above solution of the present invention, the lubricant is one of stearic acid, oleic acid, dodecanoic acid, tetradecanoic acid, polyethylene wax, polypropylene wax.

[0014] As a further improvement of the above solution of the present invention, the light stabilizer is one of 5-chlorobenzotriazole, methyl 3-[3-(benzotriazol-2-yl)-5-tert-butyl-4-hydroxyphenyl]propionate, bis(2,2,6,6-tetramethylpiperidinyl) sebacate.

[0015] The present invention also provides a method for preparing the polyolefin thermal management composite material as described above, which includes the following steps: proportionally putting copolymerized polypropylene, modified thermal management filler, toughening agent, antioxidant, lubricant, and light stabilizer into an extruder, and extruding and pelletizing to obtain the polyolefin thermal management composite material. Preferably, the extruder is a twin-screw extruder, the feeding speed of the extruder is 20 rpm, the main machine speed is 350 rpm, and the temperature control of each zone is set at 170°C, 190°C, 210°C, 210°C, 200°C, 200°C, 190°C, 190°C, 200°C, 200°C respectively. The present invention also provides an application of the polyolefin thermal management composite material as described above in automotive lighting and communication products.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. For the polyolefin radiative thermal management composite material of the present invention, the reflectivity is improved, showing a relatively high emissivity. This is because the thermal management filler can effectively improve the Mie scattering in the composite material system, thereby enhancing the reflection ability of the material. The introduction of the thermal management filler makes the polyolefin material contain functional groups such as olefin bonds, B-N bonds, and silicon-oxygen bonds, and these functional groups have high emissivity characteristics. Especially in the atmospheric window region, these functional groups endow the material with strong ability in thermal radiation, thus improving the overall emissivity of the composite material. The polyolefin radiative thermal management composite material of the present invention has been improved in both mechanical properties and thermal management properties, with better heat conduction efficiency, especially the improvement in reflectivity and emissivity.

[0017] 2. The polyolefin radiation heat management composite material of the present invention has a high solar reflectance (0.25 μm - 2.5 μm, 96%), atmospheric window emissivity (8.0 μm - 13 μm, 95%), thermal conductivity (1 - 4 W / m·K), tensile strength (15 - 25 MPa), elongation at break (30% - 55%), and flow shear rate (1.8 - 2.5 g / min). It has excellent solar reflection ability and thermal radiation emission performance, can effectively reduce the heat load on the vehicle body surface, improve the energy efficiency of the vehicle air conditioning system, and extend the service life of interior components. Therefore, the polyolefin radiation heat management composite material of the present invention has broad application potential in the automotive field. Description of the Drawings

[0018] Figure 1 It is a test result diagram of the thermal conductivity of the polyolefin heat management composite materials in Examples 1 - 3 and Comparative Examples 1 - 2; Figure 2 It is a schematic structural diagram of the thermal conductivity temperature monitoring device; Figure 3 It is a diagram of the temperature change with time during the heating process of the polyolefin heat management composite materials in Examples 1 - 3 and Comparative Examples 1 - 2. Detailed Embodiments

[0019] For the convenience of understanding the present invention, the present invention will be described more comprehensively below in conjunction with specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0021] The specific information of the raw materials used in the following examples and comparative examples is as follows: Copolymerized PP BX3800: Purchased from SINOPEC-KOREA Petrochemical; Toughening agent: POE LC565, purchased from LG Chem; Antioxidant: Irganox 1010 and Irganox 168 from BASF, Germany, mixed in a weight ratio of 2:1; Lubricant: Calcium stearate CV500, purchased from Dongguan Hanwei Technology Co., Ltd.; Light stabilizer: CYTEC ultraviolet absorber CYASORB UV - 3808PP5 from CYTEC, USA; Boron nitride powder: Purchased from Ningbo Luofei Nano Technology Co., Ltd.

[0022] The above raw materials are only for explaining the reagent sources and components used in the experiments of the present invention for full disclosure, and do not mean that the present invention cannot be realized by using other similar reagents or reagents provided by other suppliers.

[0023] Unless otherwise specified, the reagents, methods and equipment used in the present invention are all conventional reagents, methods and equipment in the technical field.

[0024] Example 1 This example presents a polyolefin thermal management composite material, which comprises the following component raw materials in parts by weight: 74 parts of copolymerized PP BX3800, 25 parts of modified thermal management filler, 12 parts of toughening agent, 0.3 part of antioxidant, 0.3 part of lubricant, and 0.3 part of light stabilizer.

[0025] The preparation method of the polyolefin thermal management composite material in this example comprises the following steps: Step 1: Dissolve 24 g of boron nitride powder in 2 L of ethanol, and add 0.2 g of sodium dodecylbenzenesulfonate (SDBS) to improve the dispersibility; then, place the mixture in an ultrasonic cleaner for ultrasonic exfoliation treatment (power: 120 W, 30 Hz, time: 60 min, temperature: 40 °C) for 1 h, and perform exfoliation through the cavitation effect generated by ultrasonic waves; after the exfoliation is completed, remove the larger particles by centrifugal separation, and finally filter the supernatant to remove the solvent and impurities, and then dry it at 60 °C under a vacuum condition of 0.3 atm for 6 h to obtain pure boron nitride nanosheets; Step 2: Disperse 20 g of the boron nitride nanosheets obtained in Step 1 in deionized water and ultrasonically treat for 3 h, and add 6.5 g of sodium bicarbonate to adjust the pH of the solution system to 8.5. Subsequently, add 2 g of tannic acid, stir at room temperature for 12 hours, and finally wash thoroughly with deionized water and dry at 80 °C under normal pressure to obtain the modified boron nitride nanosheets, which are the modified thermal management filler; Step 3: Pre-blend the modified thermal management filler, copolymerized PP BX3800, toughening agent, antioxidant, lubricant, and light stabilizer obtained in Step 2 in proportion, and then use a micro twin-screw extruder for blending and pelletizing to obtain the polyolefin thermal management composite material. Among them, the feeding speed of the micro twin-screw extruder is 20 rpm, the main machine speed is 40 rpm, and the temperature control of zones 1-10 is set at 170 °C, 190 °C, 210 °C, 210 °C, 200 °C, 200 °C, 190 °C, 190 °C, 200 °C, 200 °C.

[0026] Example 2 This embodiment uses the same implementation method as Embodiment 1. The difference from Embodiment 1 is that in this embodiment, the component raw materials and their parts by weight are as follows: 67 parts of copolymerized PP BX3800, 33 parts of modified thermal management filler, 9 parts of toughening agent, 0.2 part of antioxidant, 0.2 part of lubricant, and 0.2 part of light stabilizer.

[0027] Embodiment 3 This embodiment provides a polyolefin thermal management composite material, which comprises the following component raw materials in parts by weight: 60 parts of medium copolymerized PP BX3800, 40 parts of modified thermal management filler, 5 parts of toughening agent, 0.1 part of antioxidant, 0.1 part of lubricant, and 0.1 part of light stabilizer. The preparation method of the polyolefin thermal management composite material in this embodiment comprises the following steps: Step 1: Dissolve 48 g of boron nitride powder in 8 L of ethanol, and add 0.6 g of sodium dodecylbenzenesulfonate (SDBS) to improve the dispersibility; then, place the mixture in an ultrasonic cleaner for ultrasonic peeling treatment (power: 120 W, 30 Hz, time: 60 min, temperature: 40 °C) for 1 h, and perform peeling through the cavitation effect generated by ultrasonic waves; after the peeling is completed, remove the larger particles by centrifugal separation, and then dry at 100 °C under a vacuum condition of 0.1 atm for 8 h to obtain pure boron nitride nanosheets; Step 2: Disperse 30 g of the boron nitride nanosheets obtained in Step 1 in deionized water and perform ultrasonic treatment for 3 h, and add 19.5 g of sodium bicarbonate to adjust the pH of the solution system to 8.5. Subsequently, add 6 g of tannic acid, stir at room temperature for 12 h, and finally wash thoroughly with deionized water, and dry at 80 °C under normal pressure to obtain the modified boron nitride nanosheets, which are the modified thermal management filler; Step 3: Pre-blend the modified thermal management filler, copolymerized PP BX3800, toughening agent, antioxidant, lubricant, and light stabilizer obtained in Step 2 in proportion, and then use a micro twin-screw extruder for blending and pelletizing to obtain the polyolefin thermal management composite material. Among them, the feeding speed of the micro twin-screw extruder is 20 rpm, the main machine speed is 40 rpm, and the temperature control settings for zones 1 - 10 are 170 °C, 190 °C, 210 °C, 210 °C, 200 °C, 200 °C, 190 °C, 190 °C, 200 °C, and 200 °C.

[0028] Comparative Example 1 This comparative example presents a polyolefin thermal management composite material, which comprises the following component raw materials in parts by weight: 74 parts of copolymerized PP BX3800, 25 parts of boron nitride, 12 parts of toughening agent, 0.1 part of antioxidant, 0.1 part of lubricant, and 0.1 part of light stabilizer. The preparation method of the polyolefin thermal management composite material in this comparative example includes the following steps: pre-blend the copolymerized PP BX3800, boron nitride, toughening agent, antioxidant, lubricant, and light stabilizer in proportion, and then use a micro twin-screw extruder for blending and pelletizing to obtain the polyolefin thermal management composite material. Among them, the feeding speed of the micro twin-screw extruder is 20 rpm, the main machine speed is 40 rpm, and the temperature control of zones 1 - 10 is set at 170°C, 190°C, 210°C, 210°C, 200°C, 200°C, 190°C, 190°C, 200°C, 200°C.

[0029] Comparative Example 2 This comparative example presents a polyolefin thermal management composite material, which comprises the following component raw materials in parts by weight: 74 parts of copolymerized PP BX3800, 25 parts of exfoliated boron nitride, 12 parts of toughening agent, 0.1 part of antioxidant, 0.1 part of lubricant, and 0.1 part of light stabilizer. The preparation method of the polyolefin thermal management composite material in this comparative example includes the following steps: Step 1: Dissolve 24 g of boron nitride powder in 2 L of ethanol, and add 0.2 g of sodium dodecylbenzenesulfonate (SDBS) to improve the dispersibility; then, place the mixture in an ultrasonic cleaner for ultrasonic exfoliation treatment (power: 120 W, 30 Hz, time: 60 min, temperature: 40°C) for 1 h, and perform exfoliation through the cavitation effect generated by ultrasonic waves; after the exfoliation is completed, remove the larger particles by centrifugal separation, and finally filter the supernatant to remove the solvent and impurities, and then dry it at 60°C under a vacuum condition of 0.3 atm for 6 h to obtain pure boron nitride nanosheets; Step 2: Pre-blend the exfoliated boron nitride, copolymerized PP BX3800, toughening agent, antioxidant, lubricant, and light stabilizer obtained in Step 1 in proportion, and then use a micro twin-screw extruder for blending and pelletizing to obtain the polyolefin thermal management composite material. Among them, the feeding speed of the micro twin-screw extruder is 20 rpm, the main machine speed is 40 rpm, and the temperature control of zones 1 - 10 is set at 170°C, 190°C, 210°C, 210°C, 200°C, 200°C, 190°C, 190°C, 200°C, 200°C.

[0030] Test Example After drying the polyolefin thermal management composites prepared in Examples 1-3 and Comparative Examples 1-2, a spline and a combustion plate (for thermal conductivity testing, cut into 100 mm * 100 mm * 2 mm) were prepared using an injection molding machine. The injection temperature was 220 °C, the mold temperature was 50 °C, and the holding pressure time was 6 s. Performance tests were carried out on the prepared splines, and the test results are shown in Table 1.

[0031] Table 1 Performance test results

[0032] In Table 1, the specific test methods for the basic physical properties of the thermal management composites are as follows: Density: Experiments were carried out using a spline with dimensions of at least 10 mm × 10 mm × 4 mm according to the requirements of Method A (immersion method) in GB / T 1033.1; Ash content: Tests were carried out at a temperature of 600 ± 25 °C according to GB / T 9345.1, Method A (direct calcination method); Melt flow rate (MFR): Experiments were carried out according to GB / T 3682 at an experimental temperature of 230 °C and a load of 2.16 Kg; Tensile strength and elongation at break: Experiments were carried out according to GB / T 1040.1 and GB / T 1040.2 using a 1A type injection molded spline at an experimental speed of 50 mm / min; Flexural strength and flexural modulus: Experiments were carried out according to GB / T 9341 with a spline size of 80 mm × 10 mm × (4.0 ± 0.2) mm at an experimental speed of 2 mm / min and a support span of 64 mm; Izod notched impact strength (23 °C): Experiments were carried out according to GB / T 1843 with a spline size of 80 mm × 10 mm × (4.0 ± 0.2) mm, a type A notch, and the notch was machined mechanically; In Table 1, the specific test methods for the solar reflectance and atmospheric emissivity of the thermal management composites are as follows: Using a UV-Vis-NIR spectrophotometer (PerkinElmer Lambda 1050) equipped with a 150 mm integrating sphere accessory, the total hemispherical reflectance (ρtotal) of the material in the 250 - 2500 nm band was measured according to ASTM E903 standard. Before testing, baseline calibration was carried out using a Spectralon® standard whiteboard. The sample was prepared as a circular thin film with a diameter of 25 mm and deposited on the surface of a quartz substrate by vacuum coating. The solar weighted reflectance (ρsolar) was calculated by Equation (1):

[0033] Where IAM1.5 It is the standard solar spectral irradiance (ASTM G173-03). Each group of samples was measured 5 times and the arithmetic mean was taken, and the test uncertainty was controlled within ±0.8%.

[0034] A radiation rate test system was built based on a Fourier transform infrared spectrometer (FTIR, Bruker Vertex 80v), referring to the standard method of ASTM E408-11. The gold plate integrating sphere method was used to measure the hemispherical emissivity (εhem) of the material in the 8-13 mm atmospheric transparent window. The surface of the sample was treated by ultra-precision polishing (Ra < 10 nm). Before the test, the system was double-point calibrated with a high-emissivity black body (Acktar Metal Velvet, ε = 0.96) and a low-emissivity gold mirror (ε = 0.02). The normal emissivity (εnorm) was calculated by Equation (2):

[0035] where ρspec is the specular reflectivity and τ is the transmittance (τ≈0 in this technical study). The spectral resolution was set to 4 cm-1, and scanning was accumulated 32 times to improve the signal-to-noise ratio. The test environment temperature was maintained at 25 ± 0.5 °C, and the relative humidity was less than 30%RH.

[0036] Table 1 results show that: As the filling amount of the modified thermal management filler increases, both the tensile strength and bending strength of the composite materials of the embodiments of the present application show an upward trend. However, compared with the comparative examples, the impact performance of the composite materials decreases significantly; in terms of reflectivity, with the introduction of the modified thermal management filler, the reflectivity of the composite materials of the embodiments of the present application has been improved. The reason for this change is that the thermal management filler can effectively improve the Mie scattering in the composite material system, thereby enhancing the reflection ability of the material; while in terms of emissivity, the composite materials of the embodiments of the present application show a relatively high emissivity. This is because the polyolefin material contains functional groups with high emissivity characteristics such as olefin bonds, B-N bonds, and silicon-oxygen bonds. Especially in the atmospheric window region, these functional groups enable the material to have a strong ability in thermal radiation, thereby improving the overall emissivity of the composite material.

[0037] Through the above analysis, it can be seen that the polyolefin thermal management composite materials of the present application have been improved in both mechanical properties and thermal management properties. Especially the improvement in reflectivity and emissivity further proves the effectiveness of the modified thermal management filler.

[0038] In this study, the thermal conductivity of the examples and comparative examples was tested by the transient plane heat source method using a Hot Disk thermal constant analyzer (TPS 2500S). The probe model used for the measurement was 5465 F1, and the radius of the probe used for the measurement was 3.189 mm. Figure 1Shows the thermal conductivity data of the polyolefin thermal management composites in Examples 1-3 and Comparative Examples 1-2. It can be clearly seen from Figure 1 the data that, compared with the comparative example samples, the thermal conductivity of the modified composites has been significantly improved whether in the unpeeled or peeled state. This change indicates that the peeling and modification processes of the filler have significantly improved the thermal conductivity of the material. Among the examples, the modified exfoliated boron nitride composite shows a more significant improvement in thermal conductivity. Through the modification treatment, the dispersion of boron nitride in the polyolefin matrix has been significantly improved, forming a more uniform dispersion network. This optimized dispersion structure enables boron nitride to play a more efficient role in heat conduction in the composite material, forming an effective heat conduction framework and greatly increasing the overall thermal conductivity of the material. The realization of this modification effect is attributed to the sufficient dispersion and interface optimization of boron nitride in the composite material, which not only enhances the thermal conductivity but also effectively improves the mechanical properties and stability of the material. Therefore, the modified composite material has better heat conduction efficiency and is suitable for a wider range of high thermal performance applications.

[0039] Combined with Figure 2 , a thermal conductivity temperature monitoring device is assembled using a constant temperature heating stage, a thermocouple, and a computer. The sample strip is placed on the constant temperature heating stage and heated to 80 °C, and the temperature of the sample is collected by the thermocouple. Figure 3 Are the comparative data of the time and temperature changes during the heating process of the polyolefin thermal management composites in Comparative Examples 1-2 and Examples 1-3 to 80 °C. It can be seen from Figure 3 that for the polyolefin composite material system, the sample of Comparative Example 1 shows a faster heating rate, and the temperature quickly approaches 80 °C and then levels off. This is mainly because the unpeeled boron nitride filler is not fully dispersed in the composite material, resulting in faster heat conduction in the polymer matrix. In contrast, the heating rate of Comparative Example 2 is relatively moderate, and the final temperature approaches 80 °C, indicating that the dispersion of the filler in the system of Comparative Example 2 is better and the heat conduction performance is optimized to a certain extent. Further comparing Examples 1-3, as the surface modification ratio increases, the heating rate of the composite material gradually slows down, and the final temperature stabilizes within a range close to 80 °C. This shows that the surface modification treatment helps to improve the dispersion of boron nitride in the polyolefin matrix, improves the heat conduction characteristics of the composite material, and further makes the heating process more stable and the thermal equilibrium more stable. This result indicates that through appropriate modification treatment, not only can the heat conduction performance of the composite material be optimized, but also its temperature response characteristics can be effectively regulated to meet more precise application requirements.

[0040] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as within the scope described in this specification.

[0041] The above-described embodiments merely represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A polyolefin thermal management composite material, characterized in that: The invention is prepared from the following components in parts by weight: 60-74 parts of copolymerized polypropylene, 25-40 parts of modified thermal management filler, 5-12 parts of toughening agent, 0.1-0.3 parts of antioxidant, 0.1-0.3 parts of lubricant and 0.1-0.5 parts of light stabilizer.

2. The polyolefin thermal management composite material according to claim 1, characterized in that: The preparation method of the modified thermal management filler is as follows: adding boron nitride powder to a solvent and mixing, adding a surfactant and then performing ultrasonic stripping treatment, centrifuging to obtain a supernatant, and drying to obtain boron nitride nanosheets; dispersing the boron nitride nanosheets in water, adjusting the pH to alkaline, adding a chemical surface modifier, stirring, washing, and drying to obtain the modified thermal management filler.

3. The polyolefin thermal management composite material according to claim 2, characterized in that: The solvent is one of deionized water, ethanol, isopropanol, and dichloromethane; and / or the surfactant is one of sodium dodecylbenzene sulfonate, polyvinyl pyrrolidone, and polyvinyl alcohol; and / or the conditions of the ultrasonic stripping treatment are: power of 90-120 W, frequency of 20-40 Hz, time of 45-75 min, and temperature of 35-45° C.

4. The polyolefin thermal management composite material according to claim 2, characterized in that: The pH is adjusted to alkaline by adding sodium bicarbonate to adjust the pH to 8-9; and / or, the chemical surface modifier is tannic acid; and / or, the amount of the chemical surface modifier added is 10%-20% of the boron nitride by mass; and / or, the stirring is stirred at room temperature for 9-15 hours, and the drying is dried at 70-90° C. and under normal pressure.

5. The polyolefin thermal management composite material according to claim 1, characterized in that: The toughening agent is one of ethylene-propylene-diene copolymer, styrene-butadiene-styrene triblock copolymer, and polystyrene-poly (ethylene-butylene)-polystyrene block copolymer.

6. The polyolefin thermal management composite material according to claim 1, characterized in that: The antioxidant is one of pentaerythritol diisodecyl diphosphite, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2,4-bis((dodecylthio)methyl)-6-methylphenol, octadecyl-3,5-bis(1,1-dimethylethyl)-4-hydroxyphenylpropionate, tris(2,4-di-tert-butylphenyl)phosphite, and N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexanediamine.

7. The polyolefin thermal management composite material according to claim 1, characterized in that: The lubricant is one of stearic acid, oleic acid, dodecanoic acid, tetradecanoic acid, polyethylene wax and polypropylene wax.

8. The polyolefin thermal management composite material according to claim 1, characterized in that: The light stabilizer is one of 5-chlorobenzotriazole, 3-[3-(benzotriazole-2-yl)-5-tert-butyl-4-hydroxyphenyl]propionic acid methyl ester, and bis-2,2,6,6-tetramethylpiperidinol ester.

9. A method for preparing the polyolefin thermal management composite material according to any one of claims 1 to 8, characterized in that: It includes the following steps: Copolymerized polypropylene, modified thermal management filler, toughening agent, antioxidant, lubricant and light stabilizer are put into an extruder in proportion, and extruded and granulated to obtain a polyolefin thermal management composite material.

10. Use of the polyolefin thermal management composite material according to any one of claims 1 to 8 in automotive lighting and communication products.

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