PC / PET composite material and preparation method and application thereof

Abstract

The invention discloses a PC / PET composite material which comprises the following components in parts by weight: 50-60 parts of PC, 15-35 parts of PET, 2-10 parts of graphene, 10-12 parts of mineral powder, 0-6 parts of a flexibilizer, 0.1-1 part of a lubricant and 0.1-0.5 part of an antioxidant, and the mineral powder is modified by a silane coupling agent, methanol and an acid solution. The invention also provides a preparation method and application of the PC / PET composite material. According to the PC / PET composite material and the preparation method and application thereof provided by the invention, PC, PET, mineral powder and graphene with different molecular weight distributions are adopted for reactive extrusion, and a ball milling process is combined, so that the heat conductivity coefficient of the PC / PET composite material is improved, and the balance of rigidity and toughness is kept.

Description

Technical Field

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

[0002] With the popularization of intelligent driving technology in new energy vehicles, the stability of lidar as a core sensing component directly determines driving safety. As an external protection and optical adaptation structure, lidar cover plate must simultaneously meet the requirements of good thermal conductivity, high mechanical strength and adaptability to extreme environments.

[0003] In practical applications, lidar covers are often installed in unobstructed areas such as the front cabin and roof of vehicles, exposed to direct sunlight for extended periods. To ensure aesthetic consistency and optical performance, a black heat-absorbing layer is typically applied to the cover surface. This layer efficiently absorbs sunlight; photon energy is absorbed by atoms in the heat-absorbing layer, triggering electron transitions that are converted into molecular thermal motion through non-radiative processes, ultimately achieving the conversion of solar energy into thermal energy. Actual measurements show that the temperature at a single point on the cover can reach 130°C, and localized surface temperatures can exceed 130°C. Due to thermal expansion and contraction, the cover material warps and deforms, and the high temperature is transferred to the internal electronic components of the lidar via heat conduction, triggering automatic power-off protection and causing the sensing system to malfunction, directly threatening the safety of autonomous driving.

[0004] Currently, these cover plates are typically manufactured using conventional engineering plastics such as polycarbonate and polyethylene terephthalate, which have low intrinsic thermal conductivity and cannot quickly dissipate heat accumulated on the surface. Although adding high thermal conductivity fillers through simple blending can improve the thermal conductivity of composite materials to some extent, it often significantly impairs the mechanical properties of the matrix material, making it difficult for the material to simultaneously meet the comprehensive requirements of high thermal conductivity, high rigidity, and high toughness for lidar cover plates. Summary of the Invention

[0005] In view of the above-mentioned shortcomings of the prior art, the present invention provides a PC / PET composite material, its preparation method and application, which uses PC, PET, mineral powder and graphene with different molecular weight distributions for reactive extrusion, combined with ball milling process, to improve the thermal conductivity of PC / PET composite material and maintain a balance between rigidity and toughness.

[0006] To achieve the above objectives, the embodiments of the present invention adopt the following technical solutions:

[0007] A PC / PET composite material comprises the following components in parts by weight: 50-60 parts PC, 15-35 parts PET, 2-10 parts graphene, 10-12 parts mineral powder, 0-6 parts toughening agent, 0.1-1 part lubricant, and 0.1-0.5 parts antioxidant, wherein the mineral powder is modified by silane coupling agent, methanol, and acidic solution.

[0008] According to one aspect of the invention, the viscosity of the PC is 6 g / 10 min to 15 g / 10 min.

[0009] According to one aspect of the invention, the PET has a weight-average molecular weight of 20,000-30,000 g / mol.

[0010] According to one aspect of the present invention, the toughening agent is one or more of polypropylene-butadiene-styrene copolymer, polymethyl methacrylate-butadiene-styrene copolymer, polymethyl methacrylate-butyl acrylate copolymer, and silicone-based toughening agents.

[0011] According to one aspect of the invention, the lubricant is one or more of pentaerythritol stearate, polydimethylsiloxane, and ethylene bis-stearamide.

[0012] According to one aspect of the invention, the antioxidant is antioxidant 168. The acidic solution is a solution of a monobasic acid, dibasic acid, or tribasic acid with a pH value of 3-5. Specifically, a low-cost and relatively safe monobasic acid can be selected, such as hydrochloric acid solution, acetic acid solution, or benzoic acid solution.

[0013] According to one aspect of the present invention, the silane coupling agent is one or more of (3-glycidyloxypropyl)trimethoxysilane, polyarylate, and rare earth salt.

[0014] According to one aspect of the present invention, the mineral powder is one or more of wollastonite powder, mica powder, brucite powder, heavy calcium carbonate, talc powder, and barite powder.

[0015] A method for preparing a PC / PET composite material includes the following steps:

[0016] The mineral powder is mixed with a silane coupling agent, then methanol and an acidic solution in a predetermined ratio are added and mixed evenly, and then dried to obtain modified mineral powder.

[0017] Modified mineral powder and graphene were ball-milled to obtain a premix.

[0018] The premixed material is added to PC, PET, toughening agent, lubricant, and antioxidant for mixing to obtain a mixed material;

[0019] The mixture is extruded, melt-granulated, cooled, and pelletized to obtain the PC / PET composite material.

[0020] According to one aspect of the present invention, extruding the mixture comprises: adding the mixture into a twin-screw extruder for melt co-extrusion, wherein the extruder temperature is: zone 2 240-250°C, zone 3 260-270°C, zone 4 260-270°C, zone 5 260-270°C, zone 6 255-265°C, zone 7 250-260°C, zone 8 250-260°C, zone 9 250-260°C, zone 10 250-260°C, and zone 11 255-265°C; the extruder screw speed is 580-620 rpm; and the residence time is 2-4 min.

[0021] According to one aspect of the invention, the ball milling time is 4-10 minutes.

[0022] According to one aspect of the present invention, the above-mentioned PC / PET composite material is used in the preparation of automotive interior and exterior trim.

[0023] Advantages of implementing this invention:

[0024] A PC / PET composite material is disclosed, incorporating mineral powder and graphene treated with a silane coupling agent. The proportions of the treated mineral powder and graphene are strictly controlled. Combined with PC and PET of varying molecular weight distributions, this significantly improves the thermal conductivity of the PC / PET composite material while maintaining a balance between rigidity and toughness. In the preparation method of this PC / PET composite material, the modified mineral powder and graphene undergo a ball milling pretreatment step. By rationally controlling the ball milling time, the interfacial bonding between the graphene and mineral powder is ensured, guaranteeing stress transfer and thermal conductivity network efficiency. Detailed Implementation

[0025] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] A PC / PET composite material comprises the following components in parts by weight: 50-60 parts PC, 15-35 parts PET, 2-10 parts graphene, 10-12 parts mineral powder, 0-6 parts toughening agent, 0.1-1 part lubricant, and 0.1-0.5 parts antioxidant. The mineral powder is modified by a silane coupling agent, methanol, and an acidic solution. The amount of silane coupling agent added is 1% of the mineral powder content, and the preset ratio of methanol to acidic solution is 1:4.

[0027] In practical applications, the viscosity of the PC is 6g / 10min-15g / 10min, such as LEXANTMPC 945A-116 or LEXANTMPC 940-201. The weight-average molecular weight of the PET is 20000-30000g / mol, such as CZ-318 from Jiangyin Xingye, without any restrictions.

[0028] In practical applications, the toughening agent is one or more of the following: polypropylene-butadiene-styrene copolymer, polymethyl methacrylate-butadiene-styrene copolymer, polymethyl methacrylate-butyl acrylate copolymer, and silicone-based toughening agents.

[0029] In practical applications, the lubricant is one or more of pentaerythritol stearate, polydimethylsiloxane, and ethylene bis-stearamide.

[0030] In practical applications, the antioxidant is antioxidant 168. The acidic solution is a monobasic, dibasic, or tribasic acid solution with a pH value of 3-5. Specifically, low-cost and relatively safe monobasic acids can be selected, such as hydrochloric acid solution, acetic acid solution, or benzoic acid solution.

[0031] In practical applications, the silane coupling agent is one or more of (3-glycidyloxypropyl)trimethoxysilane, polyarylate, and rare earth salt.

[0032] In practical applications, the mineral powder is one or more of the following: wollastonite powder, mica powder, brucite powder, heavy calcium carbonate, talc powder, and barite powder.

[0033] A method for preparing a PC / PET composite material includes the following steps:

[0034] Mineral powder is mixed with silane coupling agent, and then methanol and acidic solution in a preset ratio are added and mixed evenly. The mixture is then dried to obtain modified mineral powder. The amount of silane coupling agent added is 1% of the mineral powder content, and the preset ratio of methanol and acidic solution is 1:4.

[0035] Modified mineral powder and graphene were ball-milled to obtain a premix.

[0036] The premixed material is added to PC, PET, toughening agent, lubricant, and antioxidant for mixing to obtain a mixed material;

[0037] The mixture is extruded, melt-granulated, cooled, and pelletized to obtain the PC / PET composite material.

[0038] In practical applications, the ball milling process includes the following steps: dispersing graphene in a xylene solution using a mechanical exfoliation method, and then uniformly dispersing it through ultrasonic treatment to obtain a solution; pouring the obtained solution into a ball mill, adding modified mineral powder, and during high-speed ball milling, high temperature initiates a dehydration reaction. Through hydrogen bonding, chemical bonding, and electrostatic adsorption, combined with the buffering effect of xylene, graphene is uniformly spread on the surface of the mineral powder. The ball milling time is controlled to be 4-10 minutes. The xylene solvent is removed by high-temperature evaporation. Graphene then spreads on the surface of the modified mineral powder or partially inserts into the interlayer of the modified mineral powder through amidation, hydrogen bonding, and electrostatic adsorption, thereby forming a graphene-mineral powder composite.

[0039] In practical applications, extruding the mixture includes: adding the mixture to a twin-screw extruder for melt co-extrusion; the extruder temperatures are: zone 2 240-250℃, zone 3 260-270℃, zone 4 260-270℃, zone 5 260-270℃, zone 6 255-265℃, zone 7 250-260℃, zone 8 250-260℃, zone 9 250-260℃, zone 10 250-260℃, and zone 11 255-265℃; the extruder screw speed is 580-620 rpm; and the residence time is 2-4 min.

[0040] The aforementioned PC / PET composite material can be used to manufacture automotive interior and exterior trim such as lidar panels, air deflectors, grilles, mudguards, and auxiliary air vent brackets.

[0041] The advantages of the present invention are further illustrated below through more specific embodiments, but the scope of protection of the present invention is not limited to the following embodiments. Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods. Unless otherwise specified, the materials used in the following embodiments are commercially available or prepared according to conventional methods in the art.

[0042] Example 1

[0043] A PC / PET composite material comprises the following components in parts by weight: 51 parts PC, 25 parts PET, 6 parts graphene, 12 parts modified talc, 5 parts toughening agent, 0.7 parts lubricant, and 0.3 parts antioxidant. The preparation of the modified talc includes: mixing talc with a silane coupling agent, then adding a methanol and hydrochloric acid solution in a preset ratio of 1:4 and mixing evenly, and placing the treated mineral powder in an oven at 100-120°C for 20-30 hours to obtain modified talc.

[0044] The preparation method of the above PC / PET composite material includes:

[0045] Graphene was dispersed in xylene solution by mechanical exfoliation and then uniformly dispersed by ultrasonic treatment to obtain a solution. The obtained solution was poured into a ball mill and modified mineral powder was added and ball milled for 6 minutes. The xylene solvent was removed by high-temperature evaporation to obtain graphene-mineral powder premix.

[0046] The premixed material is added to PC, PET, toughening agent, lubricant, and antioxidant for 6 minutes to obtain a mixed material.

[0047] The mixture was fed into a twin-screw extruder for melt co-extrusion. The extruder temperatures were: 245°C in zone 2, 265°C in zone 3, 265°C in zone 4, 265°C in zone 5, 260°C in zone 6, 255°C in zone 7, 255°C in zone 8, 255°C in zone 9, 255°C in zone 10, and 260°C in zone 11. The screw speed was 600 rpm, and the residence time was 3 minutes. After extrusion, the mixture was cooled, dried, and pelletized to obtain the PC / PET composite material.

[0048] Example 2

[0049] A PC / PET composite material comprises the following components in parts by weight: 50 parts PC, 15 parts PET, 2 parts graphene, 10 parts modified talc, 0.1 parts lubricant, and 0.1 parts antioxidant. The preparation of the modified talc comprises: mixing talc with a silane coupling agent, then adding a methanol and hydrochloric acid solution in a preset ratio of 1:4 and mixing evenly, and placing the treated mineral powder in an oven at 100-120°C for 20-30 hours to obtain modified talc.

[0050] The preparation method of the above PC / PET composite material includes:

[0051] Graphene was dispersed in xylene solution by mechanical exfoliation and then uniformly dispersed by ultrasonic treatment to obtain a solution. The obtained solution was poured into a ball mill and modified mineral powder was added and ball milled for 4 minutes. The xylene solvent was removed by high-temperature evaporation to obtain graphene-mineral powder premix.

[0052] The premixed material is added to PC, PET, toughening agent, lubricant, and antioxidant for 6 minutes to obtain a mixed material.

[0053] The mixture was fed into a twin-screw extruder for melt co-extrusion. The extruder temperatures were: 245°C in zone 2, 265°C in zone 3, 265°C in zone 4, 265°C in zone 5, 260°C in zone 6, 255°C in zone 7, 255°C in zone 8, 255°C in zone 9, 255°C in zone 10, and 260°C in zone 11. The screw speed was 600 rpm, and the residence time was 3 minutes. After extrusion, the mixture was cooled, dried, and pelletized to obtain the PC / PET composite material.

[0054] Example 3

[0055] A PC / PET composite material comprises the following components in parts by weight: 60 parts PC, 35 parts PET, 10 parts graphene, 12 parts modified talc, 6 parts toughening agent, 1 part lubricant, and 0.5 parts antioxidant. The preparation of the modified talc comprises: mixing talc with a silane coupling agent, then adding a methanol and hydrochloric acid solution in a preset ratio of 1:4 and mixing evenly, and placing the treated mineral powder in an oven at 100-120°C for 20-30 hours to obtain modified talc.

[0056] The preparation method of the above PC / PET composite material includes:

[0057] Graphene was dispersed in xylene solution by mechanical exfoliation and then uniformly dispersed by ultrasonic treatment to obtain a solution. The obtained solution was poured into a ball mill and modified mineral powder was added and ball milled for 8 minutes. The xylene solvent was removed by high-temperature evaporation to obtain graphene-mineral powder premix.

[0058] The premixed material is added to PC, PET, toughening agent, lubricant, and antioxidant for 6 minutes to obtain a mixed material.

[0059] The mixture was fed into a twin-screw extruder for melt co-extrusion. The extruder temperatures were: 245°C in zone 2, 265°C in zone 3, 265°C in zone 4, 265°C in zone 5, 260°C in zone 6, 255°C in zone 7, 255°C in zone 8, 255°C in zone 9, 255°C in zone 10, and 260°C in zone 11. The screw speed was 600 rpm, and the residence time was 3 minutes. After extrusion, the mixture was cooled, dried, and pelletized to obtain the PC / PET composite material.

[0060] Example 4

[0061] The difference between Example 4 and Example 1 is that the ball milling time in the preparation method of PC / PET composite material is 4 minutes, while the rest are the same.

[0062] Example 5

[0063] The difference between Example 5 and Example 1 is that the ball milling time in the preparation method of PC / PET composite material is 8 minutes, while the rest are the same.

[0064] Example 6

[0065] The difference between Example 6 and Example 1 is that the ball milling time in the preparation method of PC / PET composite material is 10 min, while the rest are the same.

[0066] Comparative Example 1

[0067] A PC / PET composite material comprises the following components in parts by weight: 51 parts PC, 25 parts PET, 2 parts graphene, 13 parts modified talc, 5 parts toughening agent, 0.7 parts lubricant, and 0.3 parts antioxidant. The preparation of the modified talc includes: mixing talc with a silane coupling agent, then adding a methanol and hydrochloric acid solution in a preset ratio of 1:4 and mixing evenly, and placing the treated mineral powder in an oven at 100-120°C for 20-30 hours to obtain modified talc.

[0068] The preparation method of the above PC / PET composite material is the same as that in Example 1.

[0069] Comparative Example 2

[0070] A PC / PET composite material comprises the following components in parts by weight: 51 parts PC, 25 parts PET, 6 parts graphene, 6 parts modified talc, 5 parts toughening agent, 0.7 parts lubricant, and 0.3 parts antioxidant. The preparation of the modified talc includes: mixing talc with a silane coupling agent, then adding a methanol and hydrochloric acid solution in a preset ratio of 1:4 and mixing evenly, and placing the treated mineral powder in an oven at 100-120℃ for 20-30 hours to obtain modified talc.

[0071] The preparation method of the above PC / PET composite material is the same as that in Example 1.

[0072] Comparative Example 3

[0073] A PC / PET composite material comprises the following components in parts by weight: 51 parts PC, 25 parts PET, 6 parts graphene, 12 parts talc, 5 parts toughening agent, 0.7 parts lubricant, and 0.3 parts antioxidant.

[0074] The preparation method of the above PC / PET composite material is the same as that in Example 1.

[0075] Comparative Example 4

[0076] A PC / PET composite material comprises the following components in parts by weight: 51 parts PC, 25 parts PET, 18 parts modified talc, 5 parts toughening agent, 0.7 parts lubricant, and 0.3 parts antioxidant. The preparation of the modified talc includes: mixing talc with a silane coupling agent, then adding a methanol and hydrochloric acid solution in a preset ratio of 1:4 and mixing evenly, and placing the treated mineral powder in an oven at 100-120°C for 20-30 hours to obtain modified talc.

[0077] The preparation method of the above PC / PET composite material is the same as that in Example 1.

[0078] Comparative Example 5

[0079] A PC / PET composite material comprises the following components in parts by weight: 51 parts PC, 25 parts PET, 18 parts graphene, 5 parts toughening agent, 0.7 parts lubricant, and 0.3 parts antioxidant.

[0080] The preparation method of the above PC / PET composite material is the same as that in Example 1.

[0081] Comparative Example 6

[0082] The difference between Comparative Example 6 and Example 1 is that the ball milling time in the preparation method of the PC / PET composite material is 12 min, while the rest are the same.

[0083] The preparation method of the above PC / PET composite material is the same as that in Example 1.

[0084] Comparative Example 7

[0085] The difference between Comparative Example 7 and Example 1 is that the ball milling time in the preparation method of the PC / PET composite material is 14 min, while the rest are the same.

[0086] The preparation method of the above PC / PET composite material is the same as that in Example 1.

[0087] Comparative Example 8

[0088] The difference between Comparative Example 8 and Example 1 is that the ball milling time in the preparation method of the PC / PET composite material is 3 minutes, while the rest are the same.

[0089] The preparation method of the above PC / PET composite material is the same as that in Example 1.

[0090] Performance testing:

[0091] The vertical and horizontal thermal conductivity of the PC / PET composite materials provided in Examples 1-6 and Comparative Examples 1-7 were tested. Simultaneously, their flexural modulus, notched impact strength of a simply supported beam, and elongation at break were determined. Specifically, the vertical and horizontal thermal conductivity were determined according to ASTM E1461-01, the flexural modulus according to DIN ENISO 178, the notched impact strength of a simply supported beam according to DIN ENISO 179-1eA, and the elongation at break according to DIN ENISO 527. The test results are shown in Table 1 below:

[0092] Table 1

[0093]

[0094]

[0095] As shown in Table 1, the PC / PET composite materials obtained in Examples 1-5 have high thermal conductivity and flexural modulus, while their notched beam impact strength and elongation at break are also excellent, thus achieving a good balance between material rigidity, toughness and thermal conductivity.

[0096] Analysis of Example 1 and Comparative Example 1 shows that when the proportion of mineral powder is too high, the heat conduction path is mainly formed by the connections between mineral powder particles. Although this structure can form a heat conduction network, the upper limit of the overall thermal conductivity is low, resulting in a limited increase in the thermal conductivity of the composite material.

[0097] Analysis of Example 1 and Comparative Example 2 reveals that an excessively high graphene content leads to insufficient contact between graphene sheets, significantly increasing interfacial thermal resistance. Heat is difficult to transfer effectively from the heat source to the graphene network; high graphene content also makes it prone to agglomeration, forming isolated "heat-conducting islands" rather than a connected network structure. Air gaps may even form between these agglomerates, creating thermal insulation points. Furthermore, the cost of graphene is far higher than that of mineral powder, resulting in poor economic viability.

[0098] Therefore, the thermal conductivity of mineral powder and graphene treated with silane coupling agents needs to be improved within a certain ratio range.

[0099] As can be seen from Example 1 and Comparative Example 3, talc powder without silane treatment has little effect on thermal conductivity, but the composite material has poor toughness.

[0100] As can be seen from Example 1 and Comparative Example 4, when modified talc is used to replace graphene, the modified talc itself has poor thermal conductivity, and the composite material system has no thermally conductive material inside, resulting in the lowest thermal conductivity coefficient.

[0101] As can be seen from Example 1 and Comparative Example 5, when graphene is used to replace modified talc, graphene alone has poor compatibility with PC / PET, and graphene itself is too soft to provide the rigidity required for the part.

[0102] As shown in Examples 1 / 4 / 5 and Comparative Examples 6 / 7 / 8, when the ball milling time is only 3 minutes, the physical bonding between graphene and talc is weak, affecting stress transfer and the efficiency of the thermal / electrical conduction network. This results in a composite material with a thermal conductivity of only 0.8 W / (m·K), far lower than the 1.5 W / (m·K) in Example 1. When the ball milling time exceeds 10 minutes, strong mechanical forces may damage the graphene lattice, introducing defects and reducing its intrinsic excellent properties. The thermal conductivity drops to 1.13 W / (m·K), while the flexural modulus decreases from 4250 MPa to 4085 MPa, and the toughness decreases significantly. It is evident that the overall performance of the composite material deteriorates significantly after the ball milling time exceeds 10 minutes. Therefore, controlling the ball milling time to 4-10 hours can simultaneously achieve sufficient dispersion of graphene and protection of structural integrity, ensuring that the composite material possesses a balance between high thermal conductivity and excellent mechanical properties.

[0103] The advantages of this invention are as follows: A PC / PET composite material, with the addition of mineral powder and graphene treated with a silane coupling agent, works synergistically with PC and PET of different molecular weight distributions to significantly improve the thermal conductivity of the composite material while maintaining a balance between rigidity and toughness. In the preparation method of the PC / PET composite material, the modified mineral powder and graphene undergo a ball milling pretreatment step. By reasonably controlling the ball milling time, the interfacial bonding force between graphene and mineral powder is ensured, guaranteeing stress transfer and thermal conductivity network efficiency.

[0104] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A PC / PET composite material, characterized in that, It comprises the following components in parts by weight: 50-60 parts PC, 15-35 parts PET, 2-10 parts graphene, 10-12 parts mineral powder, 0-6 parts toughening agent, 0.1-1 part lubricant, and 0.1-0.5 parts antioxidant, wherein the mineral powder is modified by silane coupling agent, methanol, and acidic solution.

2. The method for preparing a PC / PET composite material according to claim 1, characterized in that, The viscosity of the PC is 6 g / 10 min to 15 g / 10 min.

3. The method for preparing a PC / PET composite material according to claim 1, characterized in that, The weight-average molecular weight of the PET is 20,000-30,000 g / mol.

4. The method for preparing a PC / PET composite material according to claim 1, characterized in that, The toughening agent is one or more of the following: polypropylene-butadiene-styrene copolymer, polymethyl methacrylate-butadiene-styrene copolymer, polymethyl methacrylate-butyl acrylate copolymer, and silicone-based toughening agents.

5. The method for preparing a PC / PET composite material according to claim 1, characterized in that, The lubricant is one or more of pentaerythritol stearate, polydimethylsiloxane, and ethylene bis-stearamide.

6. The method for preparing a PC / PET composite material according to claim 1, characterized in that, The mineral powder is one or more of the following: wollastonite powder, mica powder, brucite powder, heavy calcium carbonate, talc powder, and barite powder.

7. The method for preparing a PC / PET composite material according to claim 1, characterized in that, The acidic solution is a hydrochloric acid solution, an acetic acid solution, or a benzoic acid solution.

8. A method for preparing a PC / PET composite material, characterized in that, Includes the following steps: The mineral powder is mixed with a silane coupling agent, and then methanol and an acidic solution in a predetermined ratio are added, mixed evenly, and dried to obtain modified mineral powder. Modified mineral powder and graphene were ball-milled to obtain a premix. The premixed material is added to PC, PET, toughening agent, lubricant, and antioxidant for mixing to obtain a mixed material; The mixture is extruded, melt-granulated, cooled, and pelletized to obtain the PC / PET composite material.

9. A method for preparing a PC / PET composite material according to claim 8, characterized in that, The ball milling time is 4-10 minutes.

10. The application of a PC / PET composite material according to any one of claims 1-7 in the preparation of automotive interior and exterior trim.

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