Carbon fiber reinforced polypropylene composite material, preparation method, parts and automobile

Abstract

This application relates to a carbon fiber reinforced polypropylene composite material and a preparation method thereof. By mass percentage, the carbon fiber reinforced polypropylene composite material comprises: 45% - 70% of high-crystalline polypropylene, 15% - 30% of recycled carbon fibers treated with a sizing agent, and a compatibilizer. The preparation method includes: treating the recycled carbon fibers with a sizing agent to obtain recycled carbon fibers treated with a sizing agent; adding the high-crystalline polypropylene and the compatibilizer from the main material inlet of the production equipment, and adding the recycled carbon fibers treated with a sizing agent from the side material inlet of the production equipment; melt-blending the added materials through the production equipment and then extruding and pelletizing to obtain the carbon fiber reinforced polypropylene composite material. The solution provided by this application can meet the lightweight design requirements of high strength and high modulus for automotive parts.

Description

Technical Field

[0001] The present application relates to the technical field of composite material processing, and particularly to a carbon fiber reinforced polypropylene composite material and a preparation method thereof. Background Art

[0002] Lightweight design is one of the key technical directions in the automotive industry. Through the lightweight design of components and the weight reduction of the whole vehicle, energy conservation, emission reduction and fuel emission reduction of the vehicle can be achieved. Therefore, at the present stage, lightweight design has received more support in the automotive industry. Among them, the materials of the whole vehicle are developing towards low density, high strength and high performance.

[0003] Taking the front-end frame of an automobile as an example, the front-end frame is an important frame structure at the front end of the automobile, and components such as a radiator, headlights, a hood lock, and a bumper beam can be integrally installed. In the early days, the front-end frame of the automobile was a metal part, which had a high weight, low integration, and a slow assembly beat. In recent years, it has been gradually replaced by a fully plastic or plastic + metal insert front-end frame. The plastic front-end frame can be integrally designed, reducing the number of parts and the production cost of parts, and at the same time, the weight reduction effect is obvious.

[0004] In the related art, a carbon fiber reinforced polypropylene composite material was disclosed, but the obtained material had a tensile strength lower than 80 MPa and a flexural modulus lower than 3000 MPa, and did not have performance advantages compared with the materials used for traditional automotive components. Therefore, it could not meet the lightweight design requirements of high strength and high modulus for automotive components. Summary of the Invention

[0005] To solve or partially solve the problems existing in the related art, the present application provides a carbon fiber reinforced polypropylene composite material and a preparation method thereof, which can meet the lightweight design requirements of high strength and high modulus for automotive components.

[0006] In the first aspect of the present application, a carbon fiber reinforced polypropylene composite material is provided. By mass percentage, the carbon fiber reinforced polypropylene composite material comprises 45% - 70% of high-crystalline polypropylene, 15% - 30% of recycled carbon fibers treated with a sizing agent, and a compatibilizer.

[0007] As an optional embodiment, the carbon fiber reinforced polypropylene composite material comprises 50% - 70% of high-crystalline polypropylene, 20% - 30% of recycled carbon fibers, 10% - 15% of compatibilizer, 3% - 5% of sizing agent, and the balance is other additives. Among them, the mass percentage of the sizing agent in the recycled carbon fibers treated with the sizing agent is 3% - 5%.

[0008] As an optional embodiment:

[0009] The other additives at least include an antioxidant, a coupling agent, a nucleating agent, a lubricant, and a weathering agent;

[0010] The antioxidant accounts for 0.1%-0.3% by mass of the carbon fiber reinforced polypropylene composite; the coupling agent accounts for 0.3-0.5% by mass of the carbon fiber reinforced polypropylene composite. The nucleating agent accounts for 0.2-0.5% by mass of the carbon fiber reinforced polypropylene composite; the lubricant accounts for 0.5-1% by mass of the carbon fiber reinforced polypropylene composite; the weathering agent accounts for 0.3-0.5% by mass of the carbon fiber reinforced polypropylene composite.

[0011] As an optional embodiment, the melt flow rate of the highly crystalline polypropylene is 15-20 g / 10 min; and / or,

[0012] The recycled carbon fiber selected for the recycled carbon fiber treated with the sizing agent has a tensile strength ≥ 4500 MPa and a tensile modulus ≥ 260 GPa.

[0013] As an optional embodiment, the sizing agent includes at least one of epoxy resin, polyamide resin, polyurethane resin, phenolic resin, vinyl ester resin, and polyolefin resin.

[0014] As an optional embodiment, the recycled carbon fiber selected for the recycled carbon fiber treated with the sizing agent is recycled short carbon fiber, and the length of the recycled short carbon fiber is 5 mm - 6 mm; and / or,

[0015] The crystallinity of the highly crystalline polypropylene is 65%-75%.

[0016] As an optional embodiment, the sizing agent contains a latent crosslinking agent, and the latent crosslinking agent contains an isocyanate - NCO group.

[0017] As an optional embodiment, the latent crosslinking agent accounts for 2%-5% by mass of the sizing agent.

[0018] As an optional embodiment, the compatibilizer includes one or two of maleic anhydride grafted polypropylene and acrylic acid grafted polypropylene.

[0019] As an optional embodiment, the grafting rate of maleic anhydride in the maleic anhydride grafted polypropylene is 1.2-1.5%; and / or,

[0020] The grafting rate of acrylic acid in the acrylic acid grafted polypropylene is 1.2-1.5%.

[0021] The second aspect of the present application provides a preparation method of the above-mentioned carbon fiber reinforced polypropylene composite, including:

[0022] The recycled carbon fibers are treated with the sizing agent to obtain recycled carbon fibers treated with the sizing agent;

[0023] The highly crystalline polypropylene and the compatibilizer are added from the main material inlet of the production equipment, and the recycled carbon fibers treated with the sizing agent are added from the side material inlet of the production equipment;

[0024] The added materials are melt-blended and then extruded and pelletized through the production equipment to obtain a carbon fiber reinforced polypropylene composite material.

[0025] As an optional embodiment, the screw speed of the production equipment is 100 rpm - 200 rpm.

[0026] The third aspect of the present application provides an automotive component, which is prepared from the above-mentioned carbon fiber reinforced polypropylene composite material.

[0027] The fourth aspect of the present application provides an automobile, including the above-mentioned automotive component.

[0028] The technical solution provided by the present application may include the following beneficial effects: In the embodiments of the present application, highly crystalline polypropylene is used as the base material, recycled carbon fibers treated with a sizing agent are used as the reinforcing material, and a compatibilizer is used to improve the compatibility between the highly crystalline polypropylene and the recycled carbon fibers, greatly improving the bonding ability between the carbon fibers and the polypropylene matrix resin, resulting in a low-cost and high-modulus carbon fiber reinforced polypropylene composite material, which can be applied to the lightweight design of automotive components. Compared with the current materials used for automotive components, it has ultra-high strength and modulus, and under the same strength and stiffness requirements, the components can be designed with a thinner thickness.

[0029] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present application. Brief Description of the Drawings

[0030] By describing the exemplary embodiments of the present application in more detail in conjunction with the drawings, the above and other objects, features, and advantages of the present application will become more obvious. Among them, in the exemplary embodiments of the present application, the same reference numerals generally represent the same components.

[0031] Figure 1 It is a schematic flow chart of a method for preparing a carbon fiber reinforced polypropylene composite material shown in the embodiments of the present application. Detailed Embodiments

[0032] Embodiments of the present application will be described in more detail below with reference to the accompanying drawings. Although the embodiments of the present application are shown in the drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present application more thorough and complete, and to fully convey the scope of the present application to those skilled in the art.

[0033] The terms used in the present application are for the purpose of describing specific embodiments only and are not intended to limit the present application. The singular forms "a", "the", and "said" used in the present application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0034] It should be understood that although the terms "first", "second", "third", etc. may be used in the present application to describe various information, such information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, the meaning of "a plurality" is two or more unless otherwise specifically defined.

[0035] In the related art, a carbon fiber reinforced polypropylene composite material and a manufacturing method thereof are disclosed, but the obtained material has a tensile strength lower than 80 MPa and a flexural modulus lower than 3000 MPa, and does not have performance advantages compared with the materials used for traditional automotive parts. Therefore, it cannot meet the lightweight design requirements of automotive parts with high strength and high modulus.

[0036] In view of the above problems, an embodiment of the present application provides a carbon fiber reinforced polypropylene composite material, which can meet the lightweight design requirements of automotive parts with high strength and high modulus.

[0037] An embodiment of the present application provides a carbon fiber reinforced polypropylene composite material. By mass percentage, the carbon fiber reinforced polypropylene composite material includes: 45%-70% high-crystalline polypropylene, 15%-30% recycled carbon fibers treated with a sizing agent, and a compatibilizer.

[0038] Compared with ordinary polypropylene, the high-crystalline polypropylene (HCPP) of the embodiments of the present application has high rigidity, high strength, high heat distortion temperature, good impact balance, and can be rapidly injection molded. It is a high-performance special resin. Therefore, using HCPP as the base resin for enhancing or filling polypropylene modification can bring the product performance to a higher level, and thin-walled and lightweight products can be obtained when preparing large automotive parts.

[0039] On the one hand, the cost of the recycled carbon fiber-reinforced polypropylene treated with sizing agent in the embodiments of the present application is reduced by 50% compared with that of non-recycled carbon fiber-reinforced polypropylene, providing high competitiveness for the industrial application of materials. On the other hand, the content of recycled carbon fiber in the embodiments of the present application is 15%-30%. When the content of recycled carbon fiber is too low, the strength and stiffness of the prepared composite material are insufficient, with the tensile strength ≤ 75 MPa and the tensile modulus ≤ 7000 MPa; when the content of recycled carbon fiber is too high, the tensile strength and tensile modulus of the prepared composite material can be further improved, but due to the molding problems of large-sized plastic parts, the thickness of the parts can no longer be reduced. Therefore, a higher content will lead to over-performance, and at the same time, the increase in the content of recycled carbon fiber will also cause a significant increase in the material cost.

[0040] In addition, due to the poor interfacial adhesion between polypropylene and carbon fiber, the embodiments of the present application can use a sizing agent to treat the surface of recycled carbon fiber to obtain recycled carbon fiber treated with sizing agent, and the latent crosslinking agent contained in the sizing agent can form a crosslinked structure between the carbon fiber and polypropylene at the interface, thereby improving the interfacial properties of carbon fiber and polypropylene and enhancing the bonding performance between carbon fiber and polypropylene matrix resin.

[0041] The compatibilizer of the embodiments of the present application can make the composite material have good compatibility, with the carbon fiber being fully dispersed, greatly improving the mechanical properties of the composite material.

[0042] The embodiments of the present application use high-crystalline polypropylene as the base material, recycled carbon fiber treated with sizing agent as the reinforcing material, and improve the compatibility between high-crystalline polypropylene and recycled carbon fiber treated with sizing agent through a compatibilizer, greatly enhancing the bonding ability between carbon fiber and polypropylene matrix resin, resulting in a low-cost and high-modulus carbon fiber-reinforced polypropylene composite material, which is applicable to the lightweight design of automotive parts. Compared with the current materials used for automotive parts, it has ultra-high strength and modulus, and under the same strength and stiffness requirements, the parts can be designed with a reduced thickness.

[0043] As an alternative embodiment, by mass percentage, the carbon fiber reinforced polypropylene composite material comprises 50%-70% high-crystalline polypropylene, 20%-30% recycled carbon fibers treated with a sizing agent, 10%-15% compatibilizer, and the balance being other additives, wherein the sizing agent accounts for 3%-5% of the mass of the recycled carbon fibers treated with the sizing agent.

[0044] When the content of the compatibilizer is less than 10%, the affinity between the recycled carbon fibers treated with the sizing agent and polypropylene, as well as the dispersibility of the recycled carbon fibers treated with the sizing agent, cannot be fully improved; when the content of the compatibilizer is higher than 15%, due to the relatively low molecular weight of the compatibilizer, excessive content will reduce the overall mechanical properties of the composite material.

[0045] When the content of the sizing agent is less than 3%, the bonding property between the recycled carbon fibers treated with the sizing agent and high-crystalline polypropylene will be reduced, and the recycled carbon fibers themselves are prone to wire drawing during the processing, resulting in too much hairiness, poor bundling property, and poor wear resistance of the recycled carbon fibers treated with the sizing agent; when the content of the sizing agent is higher than 5%, it will cause problems such as poor carbon fiber fibrillation and increased production cost.

[0046] As an alternative embodiment, the melt flow rate of the high-crystalline polypropylene is 15-20 g / 10 min.

[0047] Under the test conditions of a test temperature of 230 °C and a nominal load of 2.16 kg, the melt mass flow rate MFR range of the high-crystalline polypropylene HCPP selected in the embodiments of the present application is 15-20 g / 10 min. When the melt mass flow rate of the high-crystalline polypropylene is less than 15 g / 10 min, the lightweight structure design requirements of the front-end frame cannot be met. Through simulation analysis, the thickness of the prepared carbon fiber reinforced polypropylene composite material is thinned, so that the melt mass flow rate of the material is less than 15 g / 10 min, and the analyzed material cannot meet the molding requirements of the complex structure area or the area far from the gate of large automotive parts. When the melt mass flow rate of the high-crystalline polypropylene is higher than 20 g / 10 min, the flexural modulus and tensile modulus of the prepared carbon fiber reinforced polypropylene composite material both decrease to a considerable extent.

[0048] As an alternative embodiment, the tensile strength of the recycled carbon fibers selected for the recycled carbon fibers treated with the sizing agent is ≥4500 MPa, and the tensile modulus is ≥260 GPa.

[0049] The volume density of the recycled carbon fiber selected in the embodiment of the present application is 400 g / L - 420 g / L, the tensile strength is ≥4500 MPa, and the tensile modulus is ≥260 GPa. This recycled carbon fiber itself has the characteristics of high strength and high modulus. The recycled carbon fiber after sizing treatment also has the characteristics of high strength and high modulus.

[0050] Preferably, the carbon fiber reinforced polypropylene composite material of the embodiment of the present application includes: 50% - 70% high-crystalline polypropylene, 20% - 30% recycled carbon fiber after sizing treatment, 10% - 15% compatibilizer, and the balance is other additives; wherein, the mass percentage of the sizing agent in the recycled carbon fiber after sizing treatment is 3% - 5%; the melt flow rate of the high-crystalline polypropylene is 15 - 20 g / 10 min; the tensile strength of the recycled carbon fiber selected for the recycled carbon fiber after sizing treatment is ≥4500 MPa, and the tensile modulus is ≥260 GPa; and the sizing agent contains a latent crosslinking agent.

[0051] The tensile strength of the carbon fiber reinforced polypropylene composite material of the embodiment of the present application is ≥95 Mpa, the tensile modulus is ≥10500 MPa, the flexural strength is ≥140 MPa, and the flexural modulus is ≥9500 MPa.

[0052] As an alternative embodiment, the sizing agent includes at least one of epoxy resin, polyamide resin, polyurethane resin, phenolic resin, vinyl ester resin, and polyolefin resin.

[0053] In the embodiment of the present application, polyolefin resin is used as the sizing agent to facilitate the composite of the recycled carbon fiber after sizing treatment with high-crystalline polypropylene. In addition, the impregnation method is preferably used in the embodiment of the present application to make the sizing agent fully combine with the recycled carbon fiber.

[0054] As an alternative embodiment, the recycled carbon fiber selected for the recycled carbon fiber after sizing treatment is recycled short carbon fiber, and the length of the recycled short carbon fiber is 5 mm - 6 mm.

[0055] The length of the recycled short carbon fiber selected for the recycled carbon fiber after sizing treatment in the embodiment of the present application is 5 mm - 6 mm, and the shape is rice grain-like, which is convenient for feeding and dispersing during the granulation process.

[0056] As an alternative embodiment, the crystallinity of the high-crystalline polypropylene is 65% - 75%.

[0057] In the embodiments of the present application, the crystallinity of the highly crystalline polypropylene (HCPP) used can be 65%-75%, the isotacticity is ≥98%, the tensile strength is ≥35 Mpa, the tensile modulus is ≥2000 MPa, the flexural modulus is ≥2200 Mpa, and the heat distortion temperature is ≥130°C. The tensile strength, tensile modulus, etc. of this highly crystalline polypropylene are much higher than those of conventional ordinary homopolymer or copolymer polypropylene materials. Therefore, using this highly crystalline polypropylene as the base resin for enhancing or filling polypropylene modification can make the performance of the product reach a higher level, and thin-walled and lightweight products can be obtained when preparing large automotive parts.

[0058] As an optional embodiment, the sizing agent contains a latent crosslinking agent, and the latent crosslinking agent contains an isocyanate - NCO group.

[0059] The latent crosslinking agent in the embodiments of the present application has a specific isocyanate - NCO group. In the molten state of the highly crystalline polypropylene, the -NCO functional group can capture the active hydrogen in the carbon fiber and the polypropylene resin, forming a crosslinked structure at the interface between the two, thereby improving the interfacial properties between the carbon fiber and the polypropylene and enhancing the bonding performance between the carbon fiber and the polypropylene.

[0060] Preferably, the embodiments of the present application provide a chemical structural formula of a latent crosslinking agent A - NCO (A is an aliphatic blocked end):

[0061]

[0062] As a preferred embodiment, the mass percentage of the latent crosslinking agent in the sizing agent is 2%-5%.

[0063] Preferably, the mass percentage of the latent crosslinking agent in the sizing agent is 3%.

[0064] When the content of the latent crosslinking agent is too low, the interfacial properties between the carbon fiber and the polypropylene cannot be improved well; when the content of the latent crosslinking agent is too high, the dispersibility of the latent crosslinking agent in the sizing agent is poor.

[0065] As an optional embodiment, the compatibilizer includes one or two of maleic anhydride grafted polypropylene and acrylic acid grafted polypropylene. The grafting rate of maleic anhydride in maleic anhydride grafted polypropylene is 1.2 - 1.5%. The grafting rate of acrylic acid in acrylic acid grafted polypropylene is 1.2 - 1.5%.

[0066] For polypropylene materials with a low grafting rate, there will be more residues of maleic anhydride or acrylic acid, and there will also be more by-products, resulting in poor odor and volatile organic compound (VOC) performance and not meeting the automotive use requirements.

[0067] As an optional embodiment, the other additives at least include antioxidants, coupling agents, nucleating agents, lubricants and weathering agents. The antioxidant accounts for 0.1%-0.3% of the mass of the carbon fiber reinforced polypropylene composite material; the coupling agent accounts for 0.3-0.5% of the mass of the carbon fiber reinforced polypropylene composite material; the nucleating agent accounts for 0.2-0.5% of the mass of the carbon fiber reinforced polypropylene composite material; the lubricant accounts for 0.5-1% of the mass of the carbon fiber reinforced polypropylene composite material; the weathering agent accounts for 0.3-0.5% of the mass of the carbon fiber reinforced polypropylene composite material.

[0068] Among them, the antioxidant includes at least one of antioxidant 1010, antioxidant 168, and antioxidant 1076; the addition of the coupling agent can further increase the adhesion between polypropylene and carbon fiber, and improve the mechanical tensile strength, flexural strength, tensile modulus, flexural modulus, etc. of the composite material. The coupling agent includes at least one of silane coupling agents, titanate coupling agents, and aluminate coupling agents.

[0069] Corresponding to the foregoing method embodiments for realizing application functions, the present application also provides a preparation method of a carbon fiber reinforced polypropylene composite material and corresponding embodiments.

[0070] Figure 1 It is a schematic flow chart of the preparation method of the carbon fiber reinforced polypropylene composite material shown in the embodiments of the present application.

[0071] See Figure 1 , the preparation method of the carbon fiber reinforced polypropylene composite material in the embodiments of the present application includes:

[0072] S1: Treat the recycled carbon fiber with a sizing agent to obtain the recycled carbon fiber treated with the sizing agent.

[0073] According to the mass ratio that the sizing agent accounts for 3%-5% of the mass of the recycled carbon fiber treated with the sizing agent, impregnate the recycled carbon fiber with the sizing agent.

[0074] S2: Add high-crystalline polypropylene and compatibilizer from the main material inlet of the production equipment, and add the recycled carbon fiber treated with the sizing agent from the side material inlet of the production equipment.

[0075] The production equipment in the embodiments of the present application can be a twin-screw extruder.

[0076] S3: Melt and blend the added materials through the production equipment and then extrude and pelletize to obtain the carbon fiber reinforced polypropylene composite material.

[0077] According to the mass ratio of 45%-70% high-crystalline polypropylene, 15%-30% recycled carbon fiber, and compatibilizer, the high-crystalline polypropylene and the compatibilizer are added from the main material inlet of the twin-screw extruder, and the recycled carbon fiber treated with sizing agent is added from the side material inlet of the twin-screw extruder. The temperatures of each region of the twin-screw extruder from the hopper to the die head are set as follows: zone 1: 185-195 °C, zone 2: 205-215 °C, zone 3: 205-215 °C, zone 4: 205-215 °C, zone 5: 205-215 °C, zone 6: 215-220 °C, zone 7: 215-220 °C, zone 8: 225-230 °C, and the head temperature of the twin-screw extruder is 225-230 °C. Finally, it is melt-blended by the twin-screw extruder and then pelletized to obtain a carbon fiber-reinforced polypropylene composite material.

[0078] In the embodiment of the present application, high-crystalline polypropylene is used as the base material, recycled carbon fiber treated with sizing agent is used as the reinforcing material, and the compatibilizer is used to improve the compatibility between high-crystalline polypropylene and recycled carbon fiber treated with sizing agent, greatly improving the bonding ability between carbon fiber and polypropylene matrix resin. After melt-blending by the twin-screw extruder and then pelletizing, a low-cost and high-modulus carbon fiber-reinforced polypropylene composite material is prepared, which can be applied to the lightweight design of automotive parts. Compared with the current materials used for automotive parts, it has ultra-high strength and modulus, and under the same strength and stiffness requirements, the parts can be designed with a thinner thickness.

[0079] Preferably, by mass percentage, in the embodiment of the present application, 50%-70% high-crystalline polypropylene, 20%-30% recycled carbon fiber treated with sizing agent, 10%-15% compatibilizer, and the balance being other additives are used. And the sizing agent accounts for 3%-5% of the mass of the recycled carbon fiber treated with sizing agent. After treating the recycled carbon fiber and then performing melt-blending and extrusion pelletizing, the prepared carbon fiber-reinforced polypropylene composite material has a density of 1.0-1.06 g / m 3 , tensile strength ≥ 95 Mpa, tensile modulus ≥ 10500 MPa, flexural strength ≥ 140 MPa, flexural modulus ≥ 9500 MPa, heat distortion temperature under load ≥ 150 °C, benzene ≤ 30 μg / m 3 , toluene ≤ 60 μg / m3, ethylbenzene ≤ 50 μg / m 3 , xylene ≤ 60 μg / m 3 , styrene ≤ 50 μg / m 3 , formaldehyde ≤ 50 μg / m 3 , acetaldehyde ≤ 100 μg / m 3 , acrolein ≤ 20 μg / m 3 .

[0080] As an alternative embodiment, the screw speed of the production equipment is 100 rpm - 200 rpm.

[0081] When the content of recycled carbon fiber treated with sizing agent is 20%-30%, the average retained length of carbon fiber after extrusion granulation is 1500-2000μm. The retained length of 70%-80% carbon fiber is less than 2000μm, the retained length of 10%-15% carbon fiber is less than 1500μm, and the retained length of 10%-25% carbon fiber is higher than 2000μm. When the carbon fiber content is higher than 30%, the mutual friction between fibers increases, causing more fractures and resulting in a decrease in the average length of fibers in the system. In addition, the higher the melt flow rate, the smaller the resistance of carbon fiber in the polypropylene resin matrix under the shearing action of the twin-screw, making the retained length of carbon fiber longer. Control the screw speed at 100rpm-200rpm. When the screw speed is less than 100rpm, the mixing effect of polypropylene resin, carbon fiber and additives is poor. When the screw speed is higher than 200rpm, the shearing force increases, resulting in a smaller retained length of carbon fiber and thus a decrease in the modulus of the composite material.

[0082] To further understand the present invention, the carbon fiber reinforced polypropylene composite material and its preparation method provided by the present application will be described below in conjunction with embodiments. The protection scope of the present application is not limited by the following embodiments.

[0083] Example 1:

[0084] Example 1 of the present application provides a carbon fiber reinforced polypropylene composite material and its preparation method.

[0085] By mass percentage, the carbon fiber reinforced polypropylene composite material includes: 68% high-crystalline polypropylene, 20% recycled carbon fiber treated with sizing agent, 10% compatibilizer, 0.3% coupling agent, 0.2% antioxidant, 0.5% nucleating agent, 0.5% lubricant, 0.5% weathering agent. Among them, the mass percentage of the sizing agent in the recycled carbon fiber treated with sizing agent is 3%. Among them, the crystallinity of the high-crystalline polypropylene is 68%, and the melt mass flow rate MFR is 18g / 10min; the tensile strength of the recycled carbon fiber is ≥4500Mpa, the tensile modulus is ≥260GPa, the sizing agent contains a latent cross-linking agent, and the mass percentage of the latent cross-linking agent in the sizing agent is 3%; the compatibilizer is selected as medium maleic anhydride grafted polypropylene, and the grafting rate of maleic anhydride is 1.2%.

[0086] The preparation method includes: using a twin-screw extruder for extrusion granulation

[0087] Step S1: Treat the recycled carbon fiber with a sizing agent to obtain the recycled carbon fiber treated with the sizing agent.

[0088] Step S2: Add high-crystalline polypropylene and compatibilizer from the main material inlet of the twin-screw extruder, and add the recycled carbon fiber treated with sizing agent from the side material inlet of the twin-screw extruder. Set the temperatures of each zone of the twin-screw extruder from the hopper to the die head as follows: Zone 1: 195 °C, Zone 2: 210 °C, Zone 3: 210 °C, Zone 4: 210 °C, Zone 5: 210 °C, Zone 6: 220 °C, Zone 7: 220 °C, Zone 8: 230 °C, and set the head temperature of the twin-screw extruder to 230 °C, with the screw speed of 150 rpm.

[0089] Step S3: After melt blending and extrusion granulation through the twin-screw extruder, obtain the particles of carbon fiber reinforced polypropylene composite, and the particle length is 4 mm.

[0090] Example 2:

[0091] Example 2 of this application provides a carbon fiber reinforced polypropylene composite and its preparation method. Different from Example 1 is the mass ratio of the carbon fiber reinforced polypropylene composite.

[0092] By mass percentage, the carbon fiber reinforced polypropylene composite includes: 63% high-crystalline polypropylene, 20% recycled carbon fiber treated with sizing agent, 15% compatibilizer, 0.3% coupling agent, 0.2% antioxidant, 0.5% nucleating agent, 0.5% lubricant, 0.5% weathering agent. Among them, the mass percentage of the sizing agent in the recycled carbon fiber treated with sizing agent is 3%. Among them, the crystallinity of the high-crystalline polypropylene is 68%, and the melt mass flow rate MFR is 18 g / 10 min; the tensile strength of the recycled carbon fiber ≥ 4500 Mpa, the tensile modulus ≥ 260 GPa, the sizing agent contains a latent crosslinking agent, and the mass percentage of the latent crosslinking agent in the sizing agent is 3%; the compatibilizer is selected as medium maleic anhydride grafted polypropylene, and the grafting rate of maleic anhydride is 1.2%.

[0093] The preparation method includes:

[0094] Step S1: Treat the recycled carbon fiber with a sizing agent to obtain the recycled carbon fiber treated with the sizing agent.

[0095] Step S2: Add high-crystalline polypropylene and compatibilizer from the main material inlet of the twin-screw extruder, and add the recycled carbon fiber treated with sizing agent from the side material inlet of the twin-screw extruder. Set the temperatures of each zone of the twin-screw extruder from the hopper to the die head as follows: Zone 1: 195 °C, Zone 2: 210 °C, Zone 3: 210 °C, Zone 4: 210 °C, Zone 5: 210 °C, Zone 6: 220 °C, Zone 7: 220 °C, Zone 8: 230 °C, and set the head temperature of the twin-screw extruder to 230 °C, with the screw speed of 150 rpm.

[0096] Step S3: After melt blending by a twin-screw extruder and then pelletizing, pellets of the carbon fiber reinforced polypropylene composite material are obtained, and the pellet length is 4 mm.

[0097] Example 3:

[0098] Example 3 of the present application provides a carbon fiber reinforced polypropylene composite material and a preparation method thereof. Different from Example 1, polypropylene with a higher crystallinity is used.

[0099] By mass percentage, the carbon fiber reinforced polypropylene composite material includes: 68% high-crystallinity polypropylene, 20% recycled carbon fibers treated with a sizing agent, 10% compatibilizer, 0.3% coupling agent, 0.2% antioxidant, 0.5% nucleating agent, 0.5% lubricant, 0.5% weathering agent. Among them, the mass percentage of the sizing agent in the recycled carbon fibers treated with the sizing agent is 3%. Among them, the crystallinity of the high-crystallinity polypropylene is 72%, and the melt mass flow rate MFR is 18 g / 10 min; the tensile strength of the recycled carbon fibers ≥ 4500 Mpa, the tensile modulus ≥ 260 GPa, the sizing agent contains a latent cross-linking agent, and the mass percentage of the latent cross-linking agent in the sizing agent is 3%; the compatibilizer is selected as medium maleic anhydride grafted polypropylene, and the grafting rate of maleic anhydride is 1.2%.

[0100] The preparation method includes: using a twin-screw extruder for extrusion pelletizing

[0101] Step S1: Treat the recycled carbon fibers with a sizing agent to obtain recycled carbon fibers treated with the sizing agent.

[0102] Step S2: According to the mass ratio, add the high-crystallinity polypropylene and the compatibilizer from the main material inlet of the twin-screw extruder, and add the recycled carbon fibers treated with the sizing agent from the side material inlet of the twin-screw extruder. Set the temperatures of each region of the twin-screw extruder from the hopper to the die head as follows: zone 1 at 195 °C, zone 2 at 210 °C, zone 3 at 210 °C, zone 4 at 210 °C, zone 5 at 210 °C, zone 6 at 220 °C, zone 7 at 220, zone 8 at 230 °C, and set the head temperature of the twin-screw extruder to 230 °C, and the screw speed to 150 rpm.

[0103] Step S3: After melt blending by a twin-screw extruder and then pelletizing, pellets of the carbon fiber reinforced polypropylene composite material are obtained, and the pellet length is 4 mm.

[0104] Example 4:

[0105] Example 4 of the present application provides a carbon fiber reinforced polypropylene composite material and a preparation method thereof. Different from Example 1 is the mass ratio of the carbon fiber reinforced polypropylene composite material.

[0106] By mass percentage, the carbon fiber reinforced polypropylene composite material comprises: 58% high-crystalline polypropylene, 25% recycled carbon fibers treated with a sizing agent, 15% compatibilizer, 0.3% coupling agent, 0.2% antioxidant, 0.5% nucleating agent, 0.5% lubricant, and 0.5% weathering agent. Among them, the sizing agent accounts for 3% of the mass of the recycled carbon fibers treated with the sizing agent. Among them, the crystallinity of the high-crystalline polypropylene is 68%, and the melt mass flow rate MFR is 18 g / 10 min; the tensile strength of the recycled carbon fibers is ≥4500 Mpa, the tensile modulus is ≥260 GPa, the sizing agent contains a latent cross-linking agent, and the latent cross-linking agent accounts for 3% of the mass of the sizing agent; the compatibilizer is selected as medium maleic anhydride grafted polypropylene, and the grafting rate of maleic anhydride is 1.2%.

[0107] The preparation method includes: using a twin-screw extruder for extrusion granulation

[0108] Step S1: Treat the recycled carbon fibers with a sizing agent to obtain recycled carbon fibers treated with the sizing agent.

[0109] Step S2: According to the mass ratio, add the high-crystalline polypropylene and the compatibilizer from the main material inlet of the twin-screw extruder, and add the recycled carbon fibers treated with the sizing agent from the side material inlet of the twin-screw extruder. Set the temperatures of each area of the twin-screw extruder from the hopper to the die head as follows: zone 1 at 195 °C, zone 2 at 210 °C, zone 3 at 210 °C, zone 4 at 210 °C, zone 5 at 210 °C, zone 6 at 220 °C, zone 7 at 220 °C, zone 8 at 230 °C, and set the head temperature of the twin-screw extruder at 230 °C, and the screw speed at 150 rpm.

[0110] Step S3: After melt blending through the twin-screw extruder, extrude and granulate to obtain particles of the carbon fiber reinforced polypropylene composite material, and the particle length is 4 mm.

[0111] Example 5:

[0112] Example 5 of the present application provides a carbon fiber reinforced polypropylene composite material and a preparation method thereof. Different from Example 1 is the mass ratio of the carbon fiber reinforced polypropylene composite material.

[0113] By mass percentage, the carbon fiber reinforced polypropylene composite material comprises: 53% of high-crystalline polypropylene, 30% of recycled carbon fibers treated with a sizing agent, 15% of a compatibilizer, 0.3% of a coupling agent, 0.2% of an antioxidant, 0.5% of a nucleating agent, 0.5% of a lubricant, and 0.5% of a weathering agent. Among them, the mass percentage of the sizing agent in the recycled carbon fibers treated with the sizing agent is 3%. Among them, the crystallinity of the high-crystalline polypropylene is 68%, and the melt mass flow rate MFR is 18 g / 10 min; the tensile strength of the recycled carbon fibers is ≥4500 Mpa, the tensile modulus is ≥260 GPa, the sizing agent contains a latent cross-linking agent, and the mass percentage of the latent cross-linking agent in the sizing agent is 3%; the compatibilizer is selected as medium maleic anhydride grafted polypropylene, and the grafting rate of maleic anhydride is 1.2%.

[0114] The preparation method includes: using a twin-screw extruder for extrusion granulation

[0115] Step S1: Treat the recycled short carbon fibers with a sizing agent according to the mass ratio.

[0116] Step S2: According to the mass ratio, add the high-crystalline polypropylene and the compatibilizer from the main material inlet of the twin-screw extruder, and add the recycled carbon fibers treated with the sizing agent from the side material inlet of the twin-screw extruder. Set the temperatures of each area of the twin-screw extruder from the hopper to the die head as follows: zone 1 at 195 °C, zone 2 at 210 °C, zone 3 at 210 °C, zone 4 at 210 °C, zone 5 at 210 °C, zone 6 at 220 °C, zone 7 at 220 °C, zone 8 at 230 °C, and set the head temperature of the twin-screw extruder at 230 °C, and the screw speed at 150 rpm.

[0117] Step S3: After melt blending through the twin-screw extruder, extrude and granulate to obtain the particles of the carbon fiber reinforced polypropylene composite material, and the particle length is 4 mm.

[0118] Example 6:

[0119] Example 6 of the present application provides a carbon fiber reinforced polypropylene composite material and its preparation method. Different from Example 1 is the mass ratio of the carbon fiber reinforced polypropylene composite material.

[0120] By mass percentage, the carbon fiber reinforced polypropylene composite material comprises: 58% of high-crystalline polypropylene, 30% of recycled carbon fibers treated with a sizing agent, 10% of a compatibilizer, 0.3% of a coupling agent, 0.2% of an antioxidant, 0.5% of a nucleating agent, 0.5% of a lubricant, and 0.5% of a weathering agent. Among them, the sizing agent accounts for 3% of the mass of the recycled carbon fibers treated with the sizing agent. Among them, the crystallinity of the high-crystalline polypropylene is 72%, and the melt mass flow rate MFR is 18 g / 10 min; the tensile strength of the recycled carbon fibers is ≥4500 Mpa, the tensile modulus is ≥260 GPa, the sizing agent contains a latent cross-linking agent, and the latent cross-linking agent accounts for 3% of the mass of the sizing agent; the compatibilizer is selected as medium maleic anhydride grafted polypropylene, and the grafting rate of maleic anhydride is 1.2%.

[0121] The preparation method includes: using a twin-screw extruder for extrusion granulation

[0122] Step S1: Treat the recycled carbon fibers with a sizing agent to obtain recycled carbon fibers treated with the sizing agent.

[0123] Step S2: Add the high-crystalline polypropylene and the compatibilizer from the main material inlet of the twin-screw extruder, and add the recycled carbon fibers treated with the sizing agent from the side material inlet of the twin-screw extruder. Set the temperatures of each area of the twin-screw extruder from the hopper to the die head as follows: zone 1 at 195 °C, zone 2 at 210 °C, zone 3 at 210 °C, zone 4 at 210 °C, zone 5 at 210 °C, zone 6 at 220 °C, zone 7 at 220 °C, zone 8 at 230 °C, and set the head temperature of the twin-screw extruder at 230 °C, and the screw speed at 150 rpm.

[0124] Step S3: After melt blending through the twin-screw extruder, extrude and granulate to obtain particles of the carbon fiber reinforced polypropylene composite material, and the particle length is 4 mm.

[0125] Comparative Example 1:

[0126] Comparative Example 1 of the present application provides a carbon fiber reinforced polypropylene composite material and a preparation method thereof. Different from Example 1, the polypropylene resin used is conventional low-crystalline polypropylene.

[0127] By mass percentage, the carbon fiber reinforced polypropylene composite material comprises: 68% of conventional polypropylene, 20% of recycled carbon fibers treated with a sizing agent, 10% of a compatibilizer, 0.3% of a coupling agent, 0.2% of an antioxidant, 0.5% of a nucleating agent, 0.5% of a lubricant, and 0.5% of a weathering agent. Among them, the mass percentage of the sizing agent in the recycled carbon fibers treated with the sizing agent is 3%. Among them, the crystallinity of the conventional polypropylene is 45%, and the melt mass flow rate MFR is 18 g / 10 min; the tensile strength of the recycled carbon fibers ≥ 4500 Mpa, the tensile modulus ≥ 260 GPa, the sizing agent contains a latent crosslinking agent, and the mass percentage of the latent crosslinking agent in the sizing agent is 3%; the compatibilizer is selected as medium maleic anhydride grafted polypropylene, and the grafting rate of maleic anhydride is 1.2%.

[0128] The preparation method includes: using a twin-screw extruder for extrusion granulation

[0129] Step S1: Treat the recycled carbon fibers with a sizing agent to obtain recycled carbon fibers treated with the sizing agent.

[0130] Step S2: According to the mass ratio, add the high-crystallinity polypropylene and the compatibilizer from the main material inlet of the twin-screw extruder, and add the recycled carbon fibers treated with the sizing agent from the side material inlet of the twin-screw extruder. Set the temperatures of each area of the twin-screw extruder from the hopper to the die head as follows: zone 1 at 195 °C, zone 2 at 210 °C, zone 3 at 210 °C, zone 4 at 210 °C, zone 5 at 210 °C, zone 6 at 220 °C, zone 7 at 220, zone 8 at 230 °C, and set the head temperature of the twin-screw extruder at 230 °C, and the screw speed at 150 rpm.

[0131] Step S3: After melt blending through the twin-screw extruder, extrude and granulate to obtain particles of the carbon fiber reinforced polypropylene composite material, and the particle length is 4 mm.

[0132] Comparative Example 2:

[0133] Comparative Example 2 of the present application provides a carbon fiber reinforced polypropylene composite material and a preparation method thereof. Different from Example 1, the sizing agent used does not contain a latent crosslinking agent with an -NCO characteristic group.

[0134] By mass percentage, the carbon fiber reinforced polypropylene composite material comprises: 68% high-crystalline polypropylene, 20% recycled carbon fibers treated with a sizing agent, 10% compatibilizer, 0.3% coupling agent, 0.2% antioxidant, 0.5% nucleating agent, 0.5% lubricant, and 0.5% weathering agent. Among them, the sizing agent accounts for 3% of the mass of the recycled carbon fibers treated with the sizing agent. Among them, the crystallinity of the high-crystalline polypropylene is 68%, and the melt mass flow rate MFR is 18 g / 10 min; the tensile strength of the recycled carbon fibers is ≥4500 Mpa, the tensile modulus is ≥260 GPa, and the sizing agent does not contain latent crosslinking agents; the compatibilizer is selected as medium maleic anhydride grafted polypropylene, and the grafting rate of maleic anhydride is 1.2%.

[0135] The preparation method includes: using a twin-screw extruder for extrusion granulation

[0136] Step S1: Treat the recycled carbon fibers with a sizing agent to obtain recycled carbon fibers treated with the sizing agent.

[0137] Step S2: Add the high-crystalline polypropylene and the compatibilizer into the main material inlet of the twin-screw extruder, and add the recycled carbon fibers treated with the sizing agent into the side material inlet of the twin-screw extruder. Set the temperatures of each area of the twin-screw extruder from the hopper to the die head as follows: Zone 1: 195°C, Zone 2: 210°C, Zone 3: 210°C, Zone 4: 210°C, Zone 5: 210°C, Zone 6: 220°C, Zone 7: 220°C, Zone 8: 230°C, and set the head temperature of the twin-screw extruder to 230°C, and the screw speed to 150 rpm.

[0138] Step S3: After melt blending through the twin-screw extruder, extrude and granulate to obtain particles of the carbon fiber reinforced polypropylene composite material, and the particle length is 4 mm.

[0139] Comparative Example 3:

[0140] Comparative Example 3 of the present application provides a carbon fiber reinforced polypropylene composite material and its preparation method. Different from Example 1, the content of the high-crystalline polypropylene used is higher and the amount of the compatibilizer is less.

[0141] By mass percentage, the carbon fiber reinforced polypropylene composite material comprises: 72% high-crystalline polypropylene, 20% recycled carbon fibers treated with a sizing agent, 6% compatibilizer, 0.3% coupling agent, 0.2% antioxidant, 0.5% nucleating agent, 0.5% lubricant, and 0.5% weathering agent. Among them, the sizing agent accounts for 3% of the mass of the recycled carbon fibers treated with the sizing agent. Among them, the crystallinity of the high-crystalline polypropylene is 68%, and the melt mass flow rate MFR is 18 g / 10 min; the tensile strength of the recycled carbon fibers is ≥4500 Mpa, the tensile modulus is ≥260 GPa, the sizing agent contains a latent crosslinking agent, and the latent crosslinking agent accounts for 3% of the mass of the sizing agent; the compatibilizer is selected as medium maleic anhydride grafted polypropylene, and the grafting rate of maleic anhydride is 1.2%.

[0142] The preparation method includes: using a twin-screw extruder for extrusion granulation

[0143] Step S1: Treat the recycled carbon fibers with a sizing agent to obtain recycled carbon fibers treated with the sizing agent.

[0144] Step S2: Add the high-crystalline polypropylene and the compatibilizer into the main material inlet of the twin-screw extruder, and add the recycled carbon fibers treated with the sizing agent into the side material inlet of the twin-screw extruder. Set the temperatures of each region of the twin-screw extruder from the hopper to the die head as follows: zone 1 at 195 °C, zone 2 at 210 °C, zone 3 at 210 °C, zone 4 at 210 °C, zone 5 at 210 °C, zone 6 at 220 °C, zone 7 at 220 °C, zone 8 at 230 °C, and set the head temperature of the twin-screw extruder at 230 °C, and the screw speed at 150 rpm.

[0145] Step S3: After melting and blending through the twin-screw extruder, extrude and granulate to obtain particles of the carbon fiber reinforced polypropylene composite material, and the particle length is 4 mm.

[0146] Comparative Example 4:

[0147] Comparative Example 4 of the present application provides a carbon fiber reinforced polypropylene composite material and a preparation method thereof. Different from Example 1, the content of the high-crystalline polypropylene used is higher, and the content of the recycled carbon fibers is less.

[0148] By mass percentage, the carbon fiber reinforced polypropylene composite material comprises: 72% high-crystalline polypropylene, 16% recycled carbon fibers treated with a sizing agent, 10% compatibilizer, 0.3% coupling agent, 0.2% antioxidant, 0.5% nucleating agent, 0.5% lubricant, and 0.5% weathering agent. Among them, the sizing agent accounts for 3% of the mass of the recycled carbon fibers treated with the sizing agent. Among them, the crystallinity of the high-crystalline polypropylene is 68%, and the melt mass flow rate MFR is 18 g / 10 min; the tensile strength of the recycled carbon fibers is ≥4500 Mpa, the tensile modulus is ≥260 GPa, the sizing agent contains a latent cross-linking agent, and the latent cross-linking agent accounts for 3% of the mass of the sizing agent; the compatibilizer is selected as medium maleic anhydride grafted polypropylene, and the grafting rate of maleic anhydride is 1.2%.

[0149] The preparation method includes: using a twin-screw extruder for extrusion granulation

[0150] Step S1: Treat the recycled carbon fibers with a sizing agent to obtain recycled carbon fibers treated with the sizing agent.

[0151] Step S2: According to the mass ratio, add the high-crystalline polypropylene and the compatibilizer into the main material inlet of the twin-screw extruder, and add the recycled carbon fibers treated with the sizing agent into the side material inlet of the twin-screw extruder. Set the temperatures of each region of the twin-screw extruder from the hopper to the die head as follows: zone 1 at 195 °C, zone 2 at 210 °C, zone 3 at 210 °C, zone 4 at 210 °C, zone 5 at 210 °C, zone 6 at 220 °C, zone 7 at 220 °C, zone 8 at 230 °C, and set the head temperature of the twin-screw extruder at 230 °C, and the screw speed at 150 rpm.

[0152] Step S3: After melt blending through the twin-screw extruder, extrude and granulate to obtain particles of the carbon fiber reinforced polypropylene composite material, and the particle length is 4 mm.

[0153] Comparative Example 5:

[0154] Comparative Example 5 of the present application provides a carbon fiber reinforced polypropylene composite material and a preparation method thereof. Different from Example 1, the strength of the recycled carbon fibers is not high-strength and high-modulus carbon fibers.

[0155] By mass percentage, the carbon fiber reinforced polypropylene composite material comprises: 68% of high-crystalline polypropylene, 20% of recycled carbon fibers treated with a sizing agent, 10% of a compatibilizer, 0.3% of a coupling agent, 0.2% of an antioxidant, 0.5% of a nucleating agent, 0.5% of a lubricant, and 0.5% of a weathering agent. Among them, the sizing agent accounts for 3% of the mass of the recycled carbon fibers treated with the sizing agent. Among them, the crystallinity of the high-crystalline polypropylene is 68%, and the melt mass flow rate MFR is 18 g / 10 min; the tensile strength of the recycled carbon fibers is 3500 Mpa, and the tensile modulus is 200 GPa. The sizing agent contains a latent crosslinking agent, and the latent crosslinking agent accounts for 3% of the mass of the sizing agent; the compatibilizer is selected as medium maleic anhydride grafted polypropylene, and the grafting rate of maleic anhydride is 1.2%.

[0156] The preparation method includes: using a twin-screw extruder for extrusion granulation

[0157] Step S1: Treat the recycled carbon fibers with a sizing agent to obtain recycled carbon fibers treated with the sizing agent.

[0158] Step S2: Add the high-crystalline polypropylene and the compatibilizer from the main material inlet of the twin-screw extruder, and add the recycled carbon fibers treated with the sizing agent from the side material inlet of the twin-screw extruder. Set the temperatures of each region of the twin-screw extruder from the hopper to the die head as follows: zone 1 is 195°C, zone 2 is 210°C, zone 3 is 210°C, zone 4 is 210°C, zone 5 is 210°C, zone 6 is 220°C, zone 7 is 220, zone 8 is 230°C, and set the head temperature of the twin-screw extruder to 230°C, and the screw speed is 150 rpm.

[0159] Step S3: After melt blending through the twin-screw extruder, extrude and granulate to obtain particles of the carbon fiber reinforced polypropylene composite material, and the particle length is 4 mm.

[0160] Comparative Example 6:

[0161] Comparative Example 6 of the present application provides a carbon fiber reinforced polypropylene composite material and a preparation method thereof. Different from Example 1, the content of the high-crystalline polypropylene is reduced, and the content of the compatibilizer is increased.

[0162] By mass percentage, the carbon fiber reinforced polypropylene composite material comprises: 60% high-crystalline polypropylene, 20% recycled carbon fibers treated with a sizing agent, 18% compatibilizer, 0.3% coupling agent, 0.2% antioxidant, 0.5% nucleating agent, 0.5% lubricant, and 0.5% weathering agent. Among them, the sizing agent accounts for 3% of the mass of the recycled carbon fibers treated with the sizing agent. Among them, the crystallinity of the high-crystalline polypropylene is 68%, and the melt mass flow rate MFR is 18 g / 10 min; the tensile strength of the recycled carbon fibers is ≥4500 Mpa, the tensile modulus is ≥260 GPa, the sizing agent contains a latent crosslinking agent, and the latent crosslinking agent accounts for 3% of the mass of the sizing agent; the compatibilizer is selected as medium maleic anhydride grafted polypropylene, and the grafting rate of maleic anhydride is 1.2%.

[0163] The preparation method includes: using a twin-screw extruder for extrusion granulation

[0164] Step S1: Treat the recycled carbon fibers with a sizing agent to obtain recycled carbon fibers treated with the sizing agent.

[0165] Step S2: According to the mass ratio, add the high-crystalline polypropylene and the compatibilizer from the main material inlet of the twin-screw extruder, and add the recycled carbon fibers treated with the sizing agent from the side material inlet of the twin-screw extruder. Set the temperatures of each area of the twin-screw extruder from the hopper to the die head as follows: zone 1 at 195 °C, zone 2 at 210 °C, zone 3 at 210 °C, zone 4 at 210 °C, zone 5 at 210 °C, zone 6 at 220 °C, zone 7 at 220 °C, zone 8 at 230 °C, and set the head temperature of the twin-screw extruder at 230 °C, and the screw speed at 150 rpm.

[0166] Step S3: After melting and blending through the twin-screw extruder, extrude and granulate to obtain particles of the carbon fiber reinforced polypropylene composite material, and the particle length is 4 mm.

[0167] Comparative Example 7:

[0168] Comparative Example 7 of the present application provides a carbon fiber reinforced polypropylene composite material and a preparation method thereof. Different from Example 1, the grafting rate of maleic anhydride in the compatibilizer is lower.

[0169] By mass percentage, the carbon fiber reinforced polypropylene composite material comprises: 68% high-crystalline polypropylene, 20% recycled carbon fibers treated with a sizing agent, 10% compatibilizer, 0.3% coupling agent, 0.2% antioxidant, 0.5% nucleating agent, 0.5% lubricant, and 0.5% weathering agent. Among them, the sizing agent accounts for 3% of the mass of the recycled carbon fibers treated with the sizing agent. Among them, the crystallinity of the high-crystalline polypropylene is 68%, and the melt mass flow rate MFR is 18 g / 10 min; the tensile strength of the recycled carbon fibers is ≥4500 Mpa, the tensile modulus is ≥260 GPa, the sizing agent contains a latent cross-linking agent, and the latent cross-linking agent accounts for 3% of the mass of the sizing agent; the compatibilizer is selected as medium maleic anhydride grafted polypropylene, and the grafting rate of maleic anhydride is 0.8%.

[0170] The preparation method includes: using a twin-screw extruder for extrusion granulation

[0171] Step S1: Treat the recycled carbon fibers with a sizing agent to obtain recycled carbon fibers treated with the sizing agent.

[0172] Step S2: Add the high-crystalline polypropylene and the compatibilizer from the main material inlet of the twin-screw extruder, and add the recycled carbon fibers treated with the sizing agent from the side material inlet of the twin-screw extruder. Set the temperatures of each region of the twin-screw extruder from the hopper to the die head as follows: zone 1 at 195 °C, zone 2 at 210 °C, zone 3 at 210 °C, zone 4 at 210 °C, zone 5 at 210 °C, zone 6 at 220 °C, zone 7 at 220 °C, zone 8 at 230 °C, and set the head temperature of the twin-screw extruder at 230 °C, and the screw speed at 150 rpm.

[0173] Step S3: After melt blending through the twin-screw extruder, extrude and granulate to obtain particles of the carbon fiber reinforced polypropylene composite material, and the particle length is 4 mm.

[0174] Comparative Example 8:

[0175] Comparative Example 8 of the present application provides a carbon fiber reinforced polypropylene composite material and a preparation method thereof. Different from Example 1, a high screw speed is adopted during the granulation process.

[0176] By mass percentage, the carbon fiber reinforced polypropylene composite material comprises: 68% high-crystalline polypropylene, 20% recycled carbon fibers treated with a sizing agent, 10% compatibilizer, 0.3% coupling agent, 0.2% antioxidant, 0.5% nucleating agent, 0.5% lubricant, and 0.5% weathering agent. Among them, the sizing agent accounts for 3% of the mass of the recycled carbon fibers treated with the sizing agent. Among them, the crystallinity of the high-crystalline polypropylene is 68%, and the melt mass flow rate MFR is 18 g / 10 min; the tensile strength of the recycled carbon fibers is ≥4500 Mpa, the tensile modulus is ≥260 GPa, the sizing agent contains a latent cross-linking agent, and the latent cross-linking agent accounts for 3% of the mass of the sizing agent; the compatibilizer is selected as medium maleic anhydride grafted polypropylene, and the grafting rate of maleic anhydride is 1.2%.

[0177] The preparation method includes: using a twin-screw extruder for extrusion granulation

[0178] Step S1: Treat the recycled carbon fibers with a sizing agent to obtain recycled carbon fibers treated with the sizing agent.

[0179] Step S2: Add the high-crystalline polypropylene and the compatibilizer from the main material inlet of the twin-screw extruder, and add the recycled carbon fibers treated with the sizing agent from the side material inlet of the twin-screw extruder. Set the temperatures of each area of the twin-screw extruder from the hopper to the die head as follows: zone 1 at 195 °C, zone 2 at 210 °C, zone 3 at 210 °C, zone 4 at 210 °C, zone 5 at 210 °C, zone 6 at 220 °C, zone 7 at 220 °C, zone 8 at 230 °C, and set the head temperature of the twin-screw extruder at 230 °C, and the screw speed at 300 rpm.

[0180] Step S3: After melting and blending through the twin-screw extruder, extrude and granulate to obtain particles of the carbon fiber reinforced polypropylene composite material, and the particle length is 4 mm.

[0181] Comparative Example 9:

[0182] Comparative Example 9 of the present application provides a carbon fiber reinforced polypropylene composite material and a preparation method thereof. Different from Example 1, the melt mass flow rate of the high-precision polypropylene used is higher.

[0183] By mass percentage, the carbon fiber reinforced polypropylene composite material comprises: 68% high-crystalline polypropylene, 20% recycled carbon fibers treated with a sizing agent, 10% compatibilizer, 0.3% coupling agent, 0.2% antioxidant, 0.5% nucleating agent, 0.5% lubricant, and 0.5% weathering agent. Among them, the mass percentage of the sizing agent in the recycled carbon fibers treated with the sizing agent is 3%. Among them, the crystallinity of the high-crystalline polypropylene is 68%, and the melt mass flow rate MFR is 30 g / 10 min; the tensile strength of the recycled carbon fibers ≥ 4500 Mpa, the tensile modulus ≥ 260 GPa, the sizing agent contains a latent crosslinking agent, and the mass percentage of the latent crosslinking agent in the sizing agent is 3%; the compatibilizer is selected as medium maleic anhydride grafted polypropylene, and the grafting rate of maleic anhydride is 1.2%.

[0184] The preparation method includes: using a twin-screw extruder for extrusion granulation

[0185] Step S1: Treat the recycled carbon fibers with a sizing agent to obtain recycled carbon fibers treated with the sizing agent.

[0186] Step S2: Add the high-crystalline polypropylene and the compatibilizer from the main material inlet of the twin-screw extruder, and add the recycled carbon fibers treated with the sizing agent from the side material inlet of the twin-screw extruder. Set the temperatures of each area of the twin-screw extruder from the hopper to the die head as follows: zone 1 at 195 °C, zone 2 at 210 °C, zone 3 at 210 °C, zone 4 at 210 °C, zone 5 at 210 °C, zone 6 at 220 °C, zone 7 at 220 °C, zone 8 at 230 °C, and set the head temperature of the twin-screw extruder at 230 °C, and the screw speed at 150 rpm.

[0187] Step S3: After melt blending through the twin-screw extruder, extrude and granulate to obtain particles of the carbon fiber reinforced polypropylene composite material, and the particle length is 4 mm.

[0188] Perform mechanical property tests and organic volatile compound VOC tests on the above-mentioned examples and comparative examples.

[0189] The test method for mechanical properties is as follows:

[0190] Tensile strength and tensile modulus: Conduct according to the method specified in ISO 527-2. Tensile strength test conditions: Tensile speed 5 mm / min, specimen type 1A. Tensile modulus test conditions: Tensile rate 1 mm / min;

[0191] Flexural strength and flexural modulus: Conduct according to the method specified in ISO 178, span 64 mm, specimen size: (80 ± 2) mm × (10 ± 0.2) mm × (4 ± 0.2) mm. Test speed is 2 mm / min.

[0192] The test method for VOCs is carried out according to the commonly used bag method in the automotive industry: the size of the test sample piece is 80mm×100mm. For the analysis of benzene series compounds, a thermal desorption instrument-gas chromatography / mass spectrometry (ATD-GC-MS) is used, and the analysis method is carried out according to the provisions of 5.1 in HJ / T400; for the analysis of aldehydes and ketones, a high performance liquid chromatography (HPLC) is used, and the analysis method is carried out according to the provisions of 5.2 in HJ / T400.

[0193] The test results are shown in Table 1:

[0194] Table 1 Test Results of Examples and Comparative Examples

[0195]

[0196] Corresponding to the foregoing embodiments of the application function implementation method, the present application also provides an automotive component, an automobile and corresponding embodiments.

[0197] An embodiment of the present application provides an automotive component, which is prepared from a carbon fiber reinforced polypropylene composite material. The automotive component includes a front end frame and an inner tailgate panel.

[0198] The front end frame or the inner tailgate panel prepared from the carbon fiber reinforced polypropylene composite material in the embodiment of the present application has a significantly lower density than the current materials used for the front end frame or the inner tailgate panel. Based on the high strength and high modulus characteristics of the material, a lightweight design is carried out on the front end frame or the inner tailgate panel, which can significantly reduce the number of reinforcing ribs and reduce the part thickness to 2-2.5mm, and the lightweight effect exceeds 30%. Taking the front end frame as an example, through the verification of the component performance, the first-order mode of the front end frame ≥100HZ; under the condition of 100N for the headlight bracket, the front bumper bracket, etc., the maximum deformation of the product <1mm; when a load of 1500N is applied in the X direction of the lock area, the deformation <1mm, and when a limit tensile force of 2500N is applied to the lock area, there is no fracture and no permanent deformation in the lock area of the front end frame. Under each working condition, the maximum deformation, maximum stress, strength and stiffness of the front end frame can meet the design requirements.

[0199] An embodiment of the present application provides an automobile, including the aforementioned automotive component.

[0200] Since the automobile in the embodiment of the present application uses the aforementioned automotive component, the production cost of the whole vehicle can be greatly reduced, and the safety performance of the whole vehicle can be improved.

[0201] The technical features of the above 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 the scope described in this specification.

[0202] The embodiments of the present application have been described above. The above description is exemplary and not exhaustive, and is also not limited to the disclosed embodiments. Many modifications and variations are obvious to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The choice of terms used herein is intended to best explain the principles of the embodiments, practical applications, or improvements to the technology in the market, or to enable other ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A carbon fiber reinforced polypropylene composite material, characterized in that: By mass percentage, the carbon fiber reinforced polypropylene composite material comprises 50%-70% of high-crystalline polypropylene, 20%-30% of recycled carbon fibers treated with a sizing agent, 10%-15% of a compatibilizer, and the balance being other additives; wherein, the sizing agent accounts for 3%-5% of the mass of the recycled carbon fibers treated with the sizing agent, and the sizing agent comprises at least one of epoxy resin, polyamide resin, polyurethane resin, phenolic resin, vinyl ester resin, polyolefin resin, and a latent crosslinking agent, and the latent crosslinking agent comprises an isocyanate -NCO group; the latent crosslinking agent accounts for 2%-5% of the mass of the sizing agent; the crystallinity of the high-crystalline polypropylene is 65%-75%; the tensile strength of the recycled carbon fibers selected for the recycled carbon fibers treated with the sizing agent is ≥4500 MPa, and the tensile modulus is ≥260 Gpa; the compatibilizer comprises one or two of maleic anhydride grafted polypropylene and acrylic acid grafted polypropylene.

2. The carbon fiber reinforced polypropylene composite material according to claim 1, characterized in that: The other additives at least include an antioxidant, a coupling agent, a nucleating agent, a lubricant, and a weathering agent; The antioxidant accounts for 0.1%-0.3% of the mass of the carbon fiber reinforced polypropylene composite material; the coupling agent accounts for 0.3-0.5% of the mass of the carbon fiber reinforced polypropylene composite material; the nucleating agent accounts for 0.2-0.5% of the mass of the carbon fiber reinforced polypropylene composite material; the lubricant accounts for 0.5-1% of the mass of the carbon fiber reinforced polypropylene composite material; the weathering agent accounts for 0.3-0.5% of the mass of the carbon fiber reinforced polypropylene composite material.

3. The carbon fiber reinforced polypropylene composite material according to claim 1, characterized in that: Under the test conditions of a test temperature of 230°C and a nominal load of 2.16 kg, the melt flow rate of the high-crystalline polypropylene is 15-20 g / 10 min.

4. The carbon fiber reinforced polypropylene composite material according to claim 1, characterized in that: The recycled carbon fibers selected for the recycled carbon fibers treated with the sizing agent are recycled short carbon fibers, and the length of the recycled short carbon fibers is 5 mm-6 mm.

5. The carbon fiber reinforced polypropylene composite material according to claim 1, characterized in that: The grafting rate of maleic anhydride in the maleic anhydride grafted polypropylene is 1.2-1.5%; and / or, The grafting rate of acrylic acid in the acrylic acid grafted polypropylene is 1.2-1.5%.

6. A method for preparing a carbon fiber reinforced polypropylene composite material according to any one of claims 1-5, characterized in that, Including: Treating the recycled carbon fibers with the sizing agent to obtain recycled carbon fibers treated with the sizing agent; Adding the high-crystalline polypropylene, the compatibilizer, and other additives from the main material inlet of the production equipment, and adding the recycled carbon fibers treated with the sizing agent from the side material inlet of the production equipment; Melting and blending the added materials through the production equipment and then extruding and pelletizing to obtain a carbon fiber reinforced polypropylene composite material.

7. The preparation method according to claim 6, characterized in that, The screw speed of the production equipment is 100 rpm - 200 rpm.

8. An automotive part, characterized in that, The automotive parts are prepared from the carbon fiber reinforced polypropylene composite material described in any one of claims 1 to 5.

9. A vehicle, characterized in that, It includes the automotive parts described in claim 8.

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