Carbon fiber composite structure, preparation method thereof and integrated component

Abstract

The invention discloses a carbon fiber composite structure, a preparation method thereof and an integrated component. The carbon fiber composite structure is formed by sequentially stacking a first layer, a middle layer and a second layer for co-curing, the material of the first layer comprises a first carbon fiber thermoplastic material, the material of the second layer comprises a carbon fiber thermosetting prepreg, the material of the middle layer comprises a thermoplastic material and a coupling agent, and the material of the second layer comprises a thermoplastic material and a coupling agent. According to the preparation method, the materials of the first layer and the materials of the second layer are subjected to interpenetration, entanglement and chemical reaction, so that strong molecular-level interface bonding is achieved, interface bonding of the first layer and the second layer is achieved in the co-curing process, and preparation of the carbon fiber composite structure with the high-quality surface and the high mechanical property is jointly achieved. According to the preparation process provided by the invention, the production cycle of the carbon fiber composite structure can be greatly shortened, the cost is reduced, and the prepared carbon fiber composite structure can be used in high-end and complex components, can be repeatedly used and is green and environment-friendly.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of polymer processing, and in particular to a carbon fiber composite structure and a preparation method thereof and an integrated component. BACKGROUND

[0002] Carbon fiber is a special fiber mainly composed of carbon element, has a small specific gravity and a high specific strength, has excellent performance, and is often used as a reinforcing material to form a carbon fiber reinforced composite material with resin, ceramic, metal and the like. Among them, carbon fiber reinforced resin is one of the common carbon fiber composite materials, which is widely used and can be used as one of the preferred materials for lightweight high-end equipment. However, the traditional carbon fiber reinforced resin material includes carbon fiber reinforced thermoplastic resin and carbon fiber reinforced thermosetting resin, but the carbon fiber reinforced thermoplastic resin or the carbon fiber reinforced thermosetting resin still has many performance defects, such as the rigidity and strength of the carbon fiber reinforced thermoplastic resin are still difficult to meet the requirements of high-end equipment and some special field materials, and the carbon fiber reinforced thermosetting resin has performance defects such as insufficient toughness and impact resistance. Therefore, developing carbon fiber reinforced composite resin material with excellent performance is one of the effective methods to solve the performance defects of the current carbon fiber composite material, but due to the differences in resin material types, performance and structure, etc., the heterogeneous resin forming process has the technical problem of difficult interface bonding, which further causes poor interface performance and cannot realize the preparation of high-quality carbon fiber reinforced composite resin material. SUMMARY

[0003] Therefore, it is necessary to provide a high-performance carbon fiber composite structure with excellent interface performance.

[0004] In a first aspect, the present application provides a carbon fiber composite structure formed by sequentially stacking and co-curing a first layer, an intermediate layer and a second layer, wherein the material of the first layer comprises a first carbon fiber thermoplastic material, the material of the intermediate layer comprises a thermoplastic material and a coupling agent, and the material of the second layer comprises a carbon fiber thermosetting prepreg.

[0005] In some embodiments, the thermoplastic resin in the first carbon fiber thermoplastic material includes one or more of polyamide, polypropylene, and polycarbonate; and / or, the volume fraction of carbon fiber in the first carbon fiber thermoplastic material is 45%-60%; and / or, the mass ratio of the coupling agent to the thermoplastic material is (0.5-5):100; and / or, the coupling agent includes one or more of γ-glycidyl etheroxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and γ-methacryloyloxypropyltrimethoxysilane; and / or, the thermosetting resin in the carbon fiber thermosetting prepreg includes one or more of epoxy resin and phenolic resin; and / or, the volume fraction of carbon fiber in the carbon fiber thermosetting prepreg is 60%-80%; and / or, the areal density of the carbon fiber thermosetting prepreg is 100 g / m³. 2 -400 g / m 2 ; and / or, the thickness of the first layer is 1 mm-2 mm; and / or, the thickness of the intermediate layer is 0.1 mm-1 mm; and / or, the thickness of the second layer is 0.2 mm-1 mm.

[0006] In some embodiments, the carbon fiber composite structure further includes a reinforcing layer connected to the surface of the first layer; the material of the reinforcing layer includes a second carbon fiber thermoplastic material, the second carbon fiber thermoplastic material includes chopped carbon fiber thermoplastic material, and the thermoplastic resin in the second carbon fiber thermoplastic material includes one or more of polyamide, polypropylene and polycarbonate.

[0007] Secondly, this application also provides a method for preparing a carbon fiber composite structure, comprising the following steps:

[0008] The material of the first layer undergoes a first heat treatment and is then formed into the first layer by a first molding process; the material of the first layer includes a first carbon fiber thermoplastic material.

[0009] The intermediate layer material is formed by a second molding process; the intermediate layer material includes a thermoplastic material and a coupling agent;

[0010] The first layer, the intermediate layer, and the second layer are stacked sequentially to form a composite preform. The composite preform is then subjected to vacuuming and freezing treatment to form a pre-solid. The material of the second layer includes carbon fiber thermosetting prepreg.

[0011] The pre-solid is co-cured to form a carbon fiber composite structure; during the co-curing process, the pre-solid undergoes a second heat treatment and a third molding treatment.

[0012] In some embodiments, the first heat treatment is non-contact infrared heating; and / or, the second heat treatment comprises non-contact infrared heating on the first layer and contact heating plate heating on the second layer.

[0013] and / or,

[0014] The temperature of the first heat treatment is (Tm1+10℃) to (Tm1+30℃), wherein Tm1 is the melting point of the first carbon fiber thermoplastic material; and / or, the temperature of the non-contact infrared heating during the second heat treatment is (Tm1+10℃) to (Tm1+30℃), wherein Tm1 is the melting point of the first carbon fiber thermoplastic material; and the temperature of the contact heating is 120℃-180℃.

[0015] and / or,

[0016] The processing time of the first heat treatment and the second heat treatment is independently 0.5min-5min; and / or, the applied pressure of the first molding, the second molding and the third molding is independently 5MPa-30MPa; and / or, the processing time of the first molding, the second molding and the third molding is independently 3min-10min.

[0017] In some embodiments, the composite blank is vacuumed to <-0.095MPa; and / or, the temperature of the freezing treatment is 0℃ to -20℃.

[0018] In some embodiments, after the third molding, a step of injection molding the intermediate formed after the third molding with a material of a reinforcing layer is further included.

[0019] The material of the reinforcing layer comprises a second carbon fiber thermoplastic material, and the second carbon fiber thermoplastic material comprises a chopped carbon fiber thermoplastic material.

[0020] In some embodiments, the temperature of the injection molding is (Tm2-30℃) to (Tm2+20℃), wherein Tm2 is the melting point of the material of the reinforcing layer; and / or, the pressure of the injection molding is 70MPa-100MPa; and / or, the speed of the injection molding is 50cm / s-80cm / s. 3 3 / s.

[0021] In some embodiments, during the co-curing, a curing treatment is further included, wherein the temperature of the curing is 120℃-180℃, and the time of the curing is 10min-20min.

[0022] In a third aspect, the application further provides an integrated component, which is prepared by the carbon fiber composite structure provided in the first aspect, or prepared by the preparation method provided in the second aspect.​

[0023] Compared with the conventional technology, the beneficial effects of the technical solutions of the present application include:

[0024] The present application provides a carbon fiber composite structure and a preparation method thereof. By arranging an intermediate layer between the first carbon fiber thermoplastic material and the carbon fiber thermosetting prepreg and performing co-curing, the interface bonding of the first carbon fiber thermoplastic material and the carbon fiber thermosetting prepreg is realized. The intermediate layer contains a thermoplastic material and a coupling agent, which can promote the bonding between heterogeneous materials. At the same time, the composite blank formed by sequentially stacking the carbon fiber thermoplastic material, the intermediate layer and the carbon fiber thermosetting prepreg is subjected to vacuum extraction and freezing treatment before co-curing, which strengthens the close fit between the layers in the composite blank, and then the thermoplastic material of the intermediate layer is tightly fused with the carbon fiber thermoplastic material during the co-curing process, and the coupling agent of the intermediate layer and the carbon fiber thermosetting prepreg occur mutual penetration, entanglement and chemical reaction, forming a strong molecular level interface bonding, realizing the preparation of a carbon fiber composite structure with high quality surface and high mechanical properties. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 The preparation process flow chart of the carbon fiber composite structure provided by the present application is provided.

[0026] Figure 2 The preparation process flow chart of the carbon fiber composite structure provided by the present application is provided.

[0027] Figure 3 The cross-sectional schematic diagram of the carbon fiber composite structure provided by the present application is provided.

[0028] Figure 4 The regular pattern of the surface layer fiber pattern of the carbon fiber composite structure prepared by the embodiment provided by the present application is provided.

[0029] Figure 5 The surface layer fiber pattern of the carbon fiber composite structure prepared by the comparative example provided by the present application is provided. DETAILED DESCRIPTION

[0030] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the related drawings. The preferred embodiments of the present application are shown in the drawings. However, the present application can be realized in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0031] It should be noted that when an element is referred to as being "fixed" to another element, it can be directly on the other element or there can be an intervening element. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or there can be an intervening element.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description herein is for describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0033] It can be understood that the "non-contact infrared heating" in the present application refers to that the infrared heating device does not contact the material for heating. Suitable examples include that the infrared heating device does not contact the first layer for heating, or the infrared heating device does not contact the composite blank or the pre-solid for heating.

[0034] Carbon fiber reinforced resin material includes carbon fiber reinforced thermoplastic resin and carbon fiber reinforced thermosetting resin, based on the respective performance deficiencies of single carbon fiber reinforced thermoplastic resin and single carbon fiber reinforced thermosetting resin, the demand for carbon fiber composite resin material or structure is proposed. However, the carbon fiber composite resin material or structure has poor interface performance due to heterogeneous materials, so that the prepared carbon fiber composite material or structure is difficult to meet the performance requirements of products.

[0035] Therefore, the present application aims to provide a process capable of solving the interface performance deficiency of carbon fiber composite resin structure, and further to prepare a high-performance carbon fiber composite structure to meet the requirements of high-end equipment and special fields.

[0036] In a first aspect, the present application provides a carbon fiber composite structure (see FIG. 1) Figure 3 ), which is formed by sequentially stacking and co-curing a first layer, an intermediate layer and a second layer, the material of the first layer includes a first carbon fiber thermoplastic material, the material of the intermediate layer includes a thermoplastic material and a coupling agent, and the material of the second layer includes a carbon fiber thermosetting prepreg.

[0037] The present application uses an intermediate layer material containing a thermoplastic material and a coupling agent to co-cure the first carbon fiber thermoplastic material and the carbon fiber thermosetting prepreg to achieve interface bonding and obtain excellent interface performance, thereby forming a high-performance carbon fiber composite structure.

[0038] In some embodiments, the thermoplastic resin in the first carbon fiber thermoplastic material comprises one or more of polyamide, polypropylene, and polycarbonate. As a non-limiting example, the carbon fibers in the first carbon fiber thermoplastic material and the carbon fiber thermoset prepreg each independently comprise one or more of grades T300 and T700. Illustratively, the first carbon fiber thermoplastic material comprises one or more of a T300 carbon fiber reinforced polyamide material, a T700 carbon fiber reinforced polyamide material, a T300 carbon fiber reinforced polypropylene material, and a T700 carbon fiber reinforced polypropylene material, a T300 carbon fiber reinforced polycarbonate material, and a T700 carbon fiber reinforced polycarbonate material.

[0039] In some embodiments, the volume fraction of carbon fibers in the first carbon fiber thermoplastic material is 45-60%, including but not limited to 45%, 48%, 50%, 52%, 55%, 58%, 60%, or a range formed by any two of the foregoing and values therein.

[0040] In some embodiments, the thermoset resin in the carbon fiber thermoset prepreg comprises one or more of an epoxy resin and a phenolic resin. As a non-limiting example, the carbon fiber thermoset prepreg comprises one or more of a T300 carbon fiber reinforced epoxy resin prepreg, a T700 carbon fiber reinforced epoxy resin prepreg, a T300 carbon fiber reinforced phenolic resin prepreg, and a T700 carbon fiber reinforced phenolic resin prepreg.

[0041] In some embodiments, the volume fraction of carbon fibers in the carbon fiber thermoset prepreg is 60-80%, including but not limited to 60%, 65%, 70%, 75%, 80%, or a range formed by any two of the foregoing and values therein.

[0042] In some embodiments, the areal density of the carbon fiber thermoset prepreg is 100 g / m2 2 - 400 g / m2 2 , including but not limited to 100 g / m2 2 , 150 g / m2 2 , 200 g / m2 2 , 250 g / m2 2 , 300 g / m2 2 , 350 g / m2 2 , 400 g / m2 2 , or a range formed by any two of the foregoing and values therein.

[0043] As non-limiting examples, the thermoplastic material in the intermediate layer material includes one or more of polyamide, polypropylene, and polycarbonate. Further, the material of the intermediate layer being the same kind of thermoplastic resin contained in the first carbon fiber thermoplastic material can better achieve the technical effects of the present application.

[0044] In some embodiments, the mass ratio of the coupling agent to the thermoplastic material is (0.5-5): 100, including but not limited to 0.5: 100, 1: 100, 1.5: 100, 2: 100, 2.5: 100, 3: 100, 3.5: 100, 4: 100, 4.5: 100, 5: 100, or a range formed by any two of the foregoing and numerical values within the range. The present application achieves interface treatment of carbon fiber thermoplastic material and carbon fiber thermosetting prepreg by using an intermediate layer material containing a coupling agent and a thermoplastic material. Within the ratio range of the coupling agent and the thermoplastic material, the interface bonding force and stability can be better achieved, the interface strength can be significantly improved, and thus the overall performance of the carbon fiber composite structure can be improved.

[0045] In some embodiments, the coupling agent includes one or more of γ-glycidoxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and γ-methacryloyloxypropyltrimethoxysilane.

[0046] In some embodiments, the thickness of the intermediate layer is 0.1 mm-1 mm, including but not limited to 0.1 mm, 0.2 mm, 0.4 mm, 0.6 mm, 0.8 mm, 1 mm, or a range formed by any two of the foregoing and numerical values within the range.

[0047] The carbon fiber composite structure provided by the present application has excellent performance, so that the thickness of the composite structure can be greatly reduced, the cost can be reduced, and the mass of the composite structure can be further reduced, which is beneficial to the application in lightweight equipment. As non-limiting examples, the thickness of the carbon fiber composite structure provided by the present application is 1.2 mm-4 mm. As non-limiting examples, the thickness of the first layer is 1 mm-2 mm. As non-limiting examples, the thickness of the second layer is 0.2 mm-1 mm.

[0048] In some embodiments, the carbon fiber composite structure further includes a reinforcing layer connected to the surface of the first layer. It can be understood that the reinforcing layer is connected to the partial surface or the entire surface of the first layer. It can be understood that the reinforcing layer is tightly fused to the surface of the first layer.

[0049] In some embodiments, the material of the reinforcing layer comprises a second carbon fiber thermoplastic material. By using the second carbon fiber thermoplastic material as the injection material, the material is highly adaptable to the material in the carbon fiber composite structure, further improves the interface bonding with the composite structure, and plays a performance enhancement and protection effect. As a non-limiting example, the second carbon fiber thermoplastic material comprises a chopped carbon fiber thermoplastic material. Further, the thermoplastic resin in the second carbon fiber thermoplastic material comprises one or more of polyamide, polypropylene, and polycarbonate. Still further, the length of the chopped carbon fiber in the chopped carbon fiber thermoplastic material is 0.5mm-3mm, and the volume fraction of the chopped carbon fiber in the chopped carbon fiber thermoplastic material is 20%-40%. Still further, the thermoplastic resin in the chopped carbon fiber thermoplastic material is the same as the material of the first layer.

[0050] In a second aspect, the present application further provides a method for preparing a carbon fiber composite structure, comprising the following steps:

[0051] S10, performing first heat treatment on the material of the first layer to form the first layer by first molding; the material of the first layer comprises a first carbon fiber thermoplastic material.

[0052] S20, forming the intermediate layer by second molding using the material of the intermediate layer; the material of the intermediate layer comprises a thermoplastic material and a coupling agent.

[0053] S30, sequentially stacking the first layer, the intermediate layer, and the second layer to form a composite blank, performing vacuum extraction and freezing treatment on the composite blank to form a pre-solid; the material of the second layer comprises a carbon fiber thermoset prepreg.

[0054] S40, performing co-curing on the pre-solid to form a carbon fiber composite structure; during the co-curing process, performing second heat treatment and third molding treatment on the pre-solid.

[0055] The conventional process has not achieved good bonding of the interface between the first carbon fiber reinforced thermoplastic resin and the carbon fiber reinforced thermosetting resin. The present application combines the carbon fiber thermoplastic material layer and the carbon fiber thermosetting prepreg layer through the intermediate layer formed by the thermoplastic material and the coupling agent, wherein the material is compacted by vacuum extraction to achieve close physical adhesion, promote contact between the interfaces, and further improve the bonding force of the interface; further through freezing treatment, the structure is fixed and the stability of the structure is improved. Then through the co-curing of the first layer, the intermediate layer and the second layer in close contact, the coupling agent and the thermoplastic material in the intermediate layer achieve the close combination of the first layer and the second layer, and then good interface performance and high-performance carbon fiber composite structure are obtained. In the process of the present application, the first carbon fiber thermoplastic material is also subjected to heat treatment and molding to eliminate internal stress in the material, provide favorable conditions for co-curing, and further promote good bonding between the interfaces. In addition, the carbon fiber thermosetting prepreg used in the present application as the second layer material can greatly reduce the fiber disorder caused by the high-pressure flow of thermoplastic resin, greatly improve the regularity of fiber lines in complex structure areas, and thus form a high-quality appearance.

[0056] In some embodiments, the first heat treatment is non-contact infrared heating.

[0057] In some embodiments, the second heat treatment includes non-contact infrared heating of the first layer and contact heating of the second layer. The present application uses non-contact infrared heating with fast heating rate and high heating efficiency, and does not need to move the product (the product does not need to be removed from the mold), ensuring the stability and quality of the composite structure. As a non-limiting example, contact heating uses a contact heating plate for heating, which can better achieve uniform heating.

[0058] In some embodiments, the temperature of the first heat treatment is (Tm1+10℃) to (Tm1+30℃), and the Tm1 is the melting point of the first carbon fiber thermoplastic material.

[0059] In some embodiments, during the second heat treatment, the temperature of the non-contact infrared heating is (Tm1+10℃) to (Tm1+30℃), and the Tm1 is the melting point of the first carbon fiber thermoplastic material; the temperature includes but is not limited to Tm1+10℃, Tm1+15℃, Tm1+20℃, Tm1+25℃, Tm1+30℃ or a range formed by any two of the foregoing and values within the range.

[0060] In some embodiments, during the second heat treatment, the temperature of the contact heating is 120℃-180℃.

[0061] In some embodiments, the time of the first heat treatment and the time of the second heat treatment are each independently 0.5 min to 5 min, including but not limited to 0.5 min, 1 min, 2 min, 3 min, 4 min, 5 min, or a range formed by any two of the foregoing and a number within the range thereof. In some embodiments, the time of the first heat treatment is 50 s to 200 s, including but not limited to 50 s, 60 s, 80 s, 100 s, 120 s, 140 s, 160 s, 180 s, 200 s, or a range formed by any two of the foregoing and a number within the range thereof. In some embodiments, the time of the second heat treatment is 50 s to 150 s, including but not limited to 50 s, 60 s, 80 s, 100 s, 120 s, 140 s, 150 s, or a range formed by any two of the foregoing and a number within the range thereof.

[0062] In some embodiments, the temperature of the mold in the first molding process is 80 °C to 150 °C, including but not limited to 80 °C, 90 °C, 100 °C, 110 °C, 120 °C, 130 °C, 140 °C, 150 °C, or a range formed by any two of the foregoing and a number within the range thereof. Within the temperature range, the stability of the film pressing can be better ensured and the product can be easily demolded.

[0063] In some embodiments, the temperature of the mold in the second molding process is (Tm3+10 °C) to (Tm3+30 °C), including but not limited to Tm3+10 °C, Tm3+15 °C, Tm3+20 °C, Tm3+25 °C, Tm3+30 °C, or a range formed by any two of the foregoing and a number within the range thereof, the Tm3 being the melting point of the intermediate layer thermoplastic material.

[0064] In some embodiments, the temperature of the mold in the third molding process is 120 °C to 180 °C, including but not limited to 120 °C, 130 °C, 140 °C, 150 °C, 160 °C, 170 °C, 180 °C, or a range formed by any two of the foregoing and a number within the range thereof. Within the temperature range, the stability of the film pressing can be better ensured and the product can be easily demolded.

[0065] In some embodiments, the applied pressure of the first, second, and third die pressings are each independently 5 MPa - 30 MPa, including but not limited to 5 MPa, 10 MPa, 15 MPa, 20 MPa, 25 MPa, 30 MPa, or a range formed by any two of the foregoing, and values within the range thereof. In some embodiments, the pressure applied during the first die pressing is 5 MPa - 20 MPa, including but not limited to 5 MPa, 8 MPa, 10 MPa, 12 MPa, 15 MPa, 18 MPa, 20 MPa, or a range formed by any two of the foregoing, and values within the range thereof. In some embodiments, the pressure applied during the second die pressing is 5 MPa - 10 MPa, including but not limited to 5 MPa, 6 MPa, 7 MPa, 8 MPa, 9 MPa, 10 MPa, or a range formed by any two of the foregoing, and values within the range thereof. In some embodiments, the pressure applied during the third die pressing is 10 MPa - 30 MPa, including but not limited to 10 MPa, 12 MPa, 15 MPa, 18 MPa, 20 MPa, 22 MPa, 25 MPa, 28 MPa, 30 MPa, or a range formed by any two of the foregoing, and values within the range thereof.

[0066] In some embodiments, the processing time of the first, second, and third die pressings are each independently 3 min - 10 min, including but not limited to 3 min, 4 min, 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, or a range formed by any two of the foregoing, and values within the range thereof. In some embodiments, the processing time of the first die pressing is 3 min - 10 min, including but not limited to 3 min, 4 min, 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, or a range formed by any two of the foregoing, and values within the range thereof. In some embodiments, the processing time of the second die pressing is 3 min - 5 min, including but not limited to 3 min, 4 min, 5 min, or a range formed by any two of the foregoing, and values within the range thereof. In some embodiments, the processing time of the third die pressing is 5 min - 7 min, including but not limited to 3 min, 4 min, 5 min, 6 min, 7 min, or a range formed by any two of the foregoing, and values within the range thereof.

[0067] The present application can better regulate the performance of each layer structure of the first layer, the intermediate layer, and the second layer, and the interfacial bonding force by controlling the pressure and pressure application time of each stage of die pressing, thereby obtaining a high-performance overall composite structure.

[0068] In some embodiments, the composite green body is subjected to vacuum extraction to <-0.095 MPa.

[0069] In some embodiments, the composite green body is vacuumized to <-0.095 MPa and kept under the vacuum for 10-30 min. The close adhesion and compaction of the layers in the composite green body can be better achieved, and the co-curing effect can be improved.

[0070] In some embodiments, the temperature of the freezing treatment is 0 °C to -20 °C, including but not limited to 0 °C, 5 °C, 10 °C, 15 °C, 20 °C, or a range formed by any two of the foregoing and a numerical value within the range.

[0071] Referring to FIG. 1, in some embodiments, the method comprises the following steps. Figure 2 In some embodiments, after the thermoplastic material and the coupling agent are mixed in step S20, the mixed material is further subjected to a drying treatment, and then the intermediate layer is formed by a second molding. The drying treatment is beneficial to remove the moisture in the material. As a non-limiting example, the drying treatment is vacuum drying, the temperature of the drying treatment is 80 °C-120 °C, the vacuum degree is -0.08 MPa to -0.1 MPa, and the drying time is 2-4 h.

[0072] Referring to FIG. 1, in some embodiments, the method comprises the following steps. Figure 2 In some embodiments, after the third molding, a step of injecting the intermediate body with a material of a reinforcing layer is further included. The material of the reinforcing layer includes a second carbon fiber thermoplastic material, and the second carbon fiber thermoplastic material includes a chopped carbon fiber thermoplastic material. As a non-limiting example, the thermoplastic resin in the second carbon fiber thermoplastic material includes one or more of polyamide, polypropylene, and polycarbonate.

[0073] In some embodiments, the parameter settings in the injection molding process include that the temperature of the injection molding is (Tm2-30 °C) to (Tm2+20 °C), and Tm2 is the melting point of the material of the reinforcing layer. As an example, the barrel temperature of the feeding section is (Tm2-30 °C), the barrel temperature of the melting section is (Tm2+10 °C), and the barrel temperature of the nozzle section is (Tm2+20 °C).

[0074] In some embodiments, the pressure of the injection molding is 70-100 MPa, including but not limited to 70 MPa, 75 MPa, 80 MPa, 85 MPa, 90 MPa, 95 MPa, 100 MPa, or a range formed by any two of the foregoing and a numerical value within the range.

[0075] In some embodiments, the speed of the injection molding is 50-80 cm / s, including but not limited to 50 cm / s, 55 cm / s, 60 cm / s, 65 cm / s, 70 cm / s, or a range formed by any two of the foregoing and a numerical value within the range. 3 / s-80cm 3 / s, including but not limited to 50 cm / s, 55 cm / s, 60 cm / s, 65 cm / s, 70 cm / s, or a range formed by any two of the foregoing and a numerical value within the range. 3 / s, 55 cm / s, 60 cm / s, 65 cm / s, 70 cm / s, or a range formed by any two of the foregoing and a numerical value within the range. 3 / s, 55 cm / s, 60 cm / s, 65 cm / s, 70 cm / s, or a range formed by any two of the foregoing and a numerical value within the range. 3 / s, 55 cm / s, 60 cm / s, 65 cm / s, 70 cm / s, or a range formed by any two of the foregoing and a numerical value within the range. 3 / s, 55 cm / s, 60 cm / s, 65 cm / s, 70 cm / s, or a range formed by any two of the foregoing and a numerical value within the range.3 / s, 75 cm 3 / s, 80 cm 3 / s, or a range formed by any two of the foregoing and a value within the range.

[0076] Referring to the drawings Figure 2 In some embodiments, the co-curing process further comprises curing the reinforced composite structure formed after the injection molding.

[0077] In some embodiments, the curing temperature is 120-150°C, including but not limited to 120°C, 130°C, 140°C, 150°C, or a range formed by any two of the foregoing and a value within the range.

[0078] In some embodiments, the curing time is 10-20 minutes, including but not limited to 10 minutes, 12 minutes, 14 minutes, 16 minutes, 18 minutes, 20 minutes, or a range formed by any two of the foregoing and a value within the range.

[0079] In some embodiments, before the curing process, the composite structure after the injection molding is further subjected to cooling and demolding. As a non-limiting example, the composite structure is cooled at a rate of 5-10°C / min by cooling water at a temperature of 20-25°C to avoid excessive internal stress of the composite structure. As a non-limiting example, the demolding temperature is when the temperature is lower than the heat distortion temperature of the thermoplastic resin, the mold is opened, and the composite structure is taken out.

[0080] The present application realizes excellent interface treatment by vacuumizing and freezing the composite blank with a three-layer structure, and co-curing the thermoplastic material + coupling agent as the interface layer material with the first carbon fiber thermoplastic material layer and the carbon fiber thermosetting prepreg layer, to form a high-performance carbon fiber composite structure with excellent bending strength, impact resistance, high interlaminar shear strength and interface peeling strength, while further reducing the thickness of the composite structure to achieve further lightweighting of the composite structure.

[0081] In a third aspect, the present application also provides an integrated component prepared from the carbon fiber composite structure provided in the first aspect or prepared by the preparation method provided in the second aspect. The integrated component provided by the present application includes but is not limited to aerospace structural components, high-end automobile parts, high-end sports equipment, and military equipment. Illustratively, the aerospace structural components include but are not limited to satellite brackets and / or cabin interior panels. Illustratively, the high-end automobile parts include but are not limited to racing car steering wheels, battery package shells, A / B pillars, and / or chassis components. Illustratively, the high-end sports equipment includes but is not limited to bicycle frames and racket frames.

[0082] It should be noted that the experimental methods in the following examples of the present application without specific conditions are generally according to the conventional conditions, or according to the conditions suggested by the manufacturers. The various common chemical reagents used in the examples are commercially available products, or can be prepared by those skilled in the art according to known means.

[0083] The parameters and sources of some materials, reagents and equipment involved in the specific embodiments of the present application are as follows:

[0084] CF / PA6 plate-1: T700 grade continuous carbon fiber / PA6 plate, the volume fraction of carbon fiber is 50%, the thickness is 2.0 mm, the melting point of PA6 is 220℃, and it is purchased from Qingdao Zhongji Composites Co., Ltd.

[0085] CF / PP plate-2: T300 grade continuous carbon fiber / PP plate, the volume fraction of carbon fiber is 50%, the thickness is 2.0 mm, the melting point of PP is 170℃, and it is purchased from Qingdao Zhongji Composites Co., Ltd.

[0086] CF / PC plate-3: T300 grade continuous carbon fiber / PC plate, the volume fraction of carbon fiber is 50%, the thickness is 1.5 mm, the melting point of PC is 230℃, and it is purchased from Danyang Hengbo Composites Co., Ltd.

[0087] Thermoplastic resin-1: PA6 granules, about 2 mm in length and about 2 mm in diameter, the melting point of PA6 granules is 220℃.

[0088] Thermoplastic resin-2: PP granules, about 3 mm in diameter, the melting point of PP granules is 170℃.

[0089] Thermoplastic resin-3: PC granules, about 2 mm in length and about 2 mm in diameter, the melting point of PC granules is 230℃.

[0090] T300 / Epoxy prepreg-1: T300 carbon fiber twill woven cloth-epoxy prepreg, the areal density is 200 g / m 2 , the volume fraction of carbon fiber is 60%, the thickness is 0.3 mm, and it is purchased from Toray Industries, Inc.

[0091] T700 / Phenol-Formaldehyde prepreg-2: T700 carbon fiber twill woven cloth-phenol-formaldehyde prepreg, the areal density is 300 g / m 2 , the volume fraction of carbon fiber is 72%, the thickness is 0.6 mm, and it is purchased from Zhuhai Sanzhen New Material Technology Co., Ltd.

[0092] Injection material-1: chopped carbon fiber reinforced PA6 pellets, wherein the length of the chopped carbon fiber is about 3 mm, the volume content of the chopped carbon fiber is 30%; the length of the PA6 pellets is about 2 mm, the particle size is about 2 mm, the melting point is 220℃, and it is purchased from Suzhou Xuguang Technology Development Co., Ltd.

[0093] Injection material-2: chopped carbon fiber reinforced PP pellets, wherein the length of the chopped carbon fiber is about 3 mm, the volume content of the chopped carbon fiber is 30%; the length of the PP pellets is about 2 mm, the particle size is about 2 mm, the melting point is 170℃, and it is purchased from Suzhou Xuguang Technology Development Co., Ltd.

[0094] Injection material-3: chopped carbon fiber reinforced PC pellets, wherein the length of the chopped carbon fiber is about 3 mm, the volume content of the chopped carbon fiber is 30%; the length of the PC pellets is about 2 mm, the particle size is about 2 mm, the melting point is 230℃, and it is purchased from Suzhou Xuguang Technology Development Co., Ltd.

[0095] Carbon fiber woven fabric / PA6 plate: T300 carbon fiber twill woven cloth-PA6 plate, the volume fraction of the carbon fiber twill is 50%, the thickness is 2.0 mm, the melting point of PA6 is 220℃, and it is purchased from Jiangsu Hengbo Composites Co., Ltd.

[0096] Coupling agent: γ-glycidoxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane or γ-methacryloyloxypropyltrimethoxysilane.

[0097] Non-contact infrared heating plate: from Nantong Qianwei Technology Co., Ltd.

[0098] Auxiliary material: nylon vacuum bag.

[0099] Example 1

[0100] The present embodiment provides a preparation method of a carbon fiber composite structure, and the specific steps are as follows:

[0101] The CF / PA6 plate-1 is cut into a specified shape (with a 5% volume allowance reserved), placed into a mold and positioned, the mold temperature is 100℃, the non-contact infrared heating plate is inserted into the mold through a mechanical arm, the plate is heated to 240℃, and then the first layer of the blank is obtained by molding under a pressure of 12 MPa for 5 min.

[0102] The PA6 granules were mixed with 2.5 wt% of γ-glycidoxypropyltrimethoxysilane based on the weight of the PA6 granules in a high-speed mixer at a rotation speed of 500 r / min for 10 min, and then dried in a vacuum drying box at a temperature of 100°C, a vacuum degree of -0.1 MPa, and for a time of 4 h. The dried resin was then evenly laid in a preheated mold of a film press at 240°C, and then an intermediate layer film was formed by the film press at a pressure of 5 MPa for 10 min, and the thickness of the intermediate layer film was 0.5 mm.

[0103] The T300 / Epoxy prepreg-1, the intermediate layer film, and the first layer blank were sequentially stacked in the order of top, middle, and bottom by a positioning tool to form a composite blank, the composite blank was placed in a nylon vacuum bag, vacuum was pumped to below -0.095 MPa and maintained for 10 min, and then the composite blank was placed in a freezer at -18°C for freezing treatment for 30 min to form a pre-solid.

[0104] The pre-solid was placed in an injection mold (at this time, the contact surface with the mold was the surface layer of the T300 / Epoxy prepreg-1), the mold was heated to 150°C, a non-contact infrared heating plate was then inserted into the mold by a mechanical arm to heat the surface of the first layer blank at a temperature of 240°C for 100 s, the mold was then closed and a pressure of 18 MPa was applied for 6 min, and finally the injection material-1 was injected into the cavity at an injection pressure of 80 MPa and a speed of 60 cm / s through a preset glue injection port of the mold, the mold was kept for 15 s, the mold was cooled to 75°C by passing cooling water at 25°C, the mold was opened to take out the composite structure, and the composite structure was post-cured at 130°C for 15 min to form a carbon fiber composite structure. The specific structure is shown in FIG. 2. 3 Figure 3 wherein the inner core layer is the first layer, the outer surface layer is the second layer, and the transition layer is the intermediate layer.

[0105] Example 2

[0106] The CF / PP plate-2 was cut into a specified shape (with a 5% volume allowance), placed into a mold, and positioned, the mold temperature was 80°C, a non-contact infrared heating plate was inserted into the mold by a mechanical arm to heat the plate to 200°C, and then the plate was molded at a pressure of 10 MPa for 5 min to obtain the first layer blank.

[0107] ​The PP granules were mixed with 2.5 wt% of γ-glycidoxypropyltrimethoxysilane based on the weight of the PP granules in a high-speed mixer at a rotation speed of 500 r / min for 10 min to achieve sufficient mixing, and then dried in a vacuum drying box at a temperature of 100°C, a vacuum degree of -0.1 MPa, and for a time of 4 h. The dried resin was then evenly laid in a mold of a film press preheated to 200°C, and an intermediate layer film was formed by film pressing at a pressure of 5 MPa for 10 min, and the thickness of the intermediate layer film was 0.5 mm.

[0108] The T700 / Phenol-Formaldehyde prepreg-2, the intermediate layer film, and the first layer blank were sequentially stacked in the order of top, middle, and bottom by positioning fixtures to form a composite blank, the composite blank was placed in a nylon vacuum bag, vacuum was applied by a vacuum pump to a degree of -0.095 MPa or below and maintained for 10 min, and then the composite blank was placed in a freezer at -18°C for freezing treatment for 30 min to form a pre-solidified composite blank.

[0109] The pre-solidified composite blank was placed in an injection mold (at this time, the contact surface with the mold was the surface layer of the T700 / Phenol-Formaldehyde prepreg-2), the mold was heated to 170°C, a non-contact infrared heating plate was then inserted into the mold by a mechanical arm to heat the surface of the first layer blank at a temperature of 200°C for 100 s, the mold was then closed and a pressure of 15 MPa was applied for 6 min, and finally, the injection material-2 was injected into the cavity at an injection pressure of 80 MPa and a speed of 60 cm / s through a preset glue injection port of the mold, a pressure was maintained for 15 s, the mold was cooled to 75°C by passing cooling water at 25°C, the mold was opened to take out the composite structure, and post-curing was performed at 130°C for 15 min to finally form a carbon fiber composite structure. The specific structure is shown in the accompanying drawings. 3 / s speed through a preset glue injection port of the mold, a pressure was maintained for 15 s, cooling water at 25°C was passed to cool the mold to 75°C, the mold was opened to take out the composite structure, and post-curing was performed at 130°C for 15 min to finally form a carbon fiber composite structure. The specific structure is shown in the accompanying drawings. Figure 3 wherein the inner core layer is the first layer, the outer surface layer is the second layer, and the transition layer is the intermediate layer.

[0110] Example 3

[0111] The CF / PC plate-3 was cut into a specified shape (with a 5% volume allowance), placed into a mold, and positioned, the mold temperature was 150°C, a non-contact infrared heating plate was inserted into the mold by a mechanical arm to heat the plate to 260°C, and then the plate was molded at a pressure of 16 MPa for 5 min to obtain the first layer blank.

[0112] The PC granules were mixed with 2.5 wt% of γ-glycidoxypropyltrimethoxysilane by weight of the PC granules in a high-speed mixer at a rotation speed of 500 r / min for 10 min, and then dried in a vacuum drying box at a temperature of 100°C, a vacuum degree of -0.1 MPa, and for 4 h. The dried resin was then evenly laid in a mold of a film press preheated to 260°C, and then an intermediate layer film was formed by the film press at a pressure of 5 MPa for 10 min, and the thickness of the intermediate layer film was 0.5 mm.

[0113] The T300 / Epoxy prepreg-1, the intermediate layer film, and the first layer blank were sequentially stacked in an order of top, middle, and bottom by a positioning tool to form a composite blank, the composite blank was placed in a nylon vacuum bag, vacuumized to a vacuum degree of -0.095 MPa or below by using a vacuum pump and maintained for 10 min, and then the composite blank was frozen as a whole in a freezer at -18°C for 30 min to form a pre-solidified composite blank.

[0114] The pre-solidified composite blank was placed in an injection mold (at this time, the contact surface with the mold was the surface layer of the T300 / Epoxy prepreg-1), the mold was heated to 130°C, a non-contact infrared heating plate was then inserted into the mold by a mechanical arm to heat the surface of the first layer blank at a temperature of 260°C for 100 s, the mold was then closed and a pressure of 20 MPa was applied for 6 min, and finally the injection plastic-3 was injected into the cavity at an injection pressure of 80 MPa and a speed of 60 cm³ / s through a preset injection port of the mold, the mold was cooled to 75°C by passing cooling water at 25°C, the mold was opened to take out the composite structure, and the composite structure was post-cured at 130°C for 15 min to finally form a carbon fiber composite structure. The specific structure is shown in the schematic diagram of FIG. 1. Figure 3 wherein the inner core layer is the first layer, the outer surface layer is the second layer, and the transition layer is the intermediate layer.

[0115] Example 4

[0116] The difference from Example 1 is that the coupling agent γ-glycidoxypropyltrimethoxysilane was replaced by γ-aminopropyltriethoxysilane, and the amount of the coupling agent added was changed from 2.5 wt% to 3.5 wt% by weight of the PA6 granules, and the other steps were the same as those in Example 1.

[0117] Example 5

[0118] The difference from Example 1 is that the coupling agent γ-glycidoxypropyltrimethoxysilane was replaced by γ-methacryloyloxypropyltrimethoxysilane, and the amount of the coupling agent added was changed from 2.5 wt% to 1.5 wt% by weight of the PA6 granules, and the other steps were the same as those in Example 1.

[0119] Example 6

[0120] The difference from Example 1 is that the mold is closed and a pressure of 35 MPa is applied during the pre-solid forming process, and the pressure is maintained for 3 min, and the remaining steps are consistent with Example 1.

[0121] Example 7

[0122] The difference from Example 1 is that the temperature of the mold during the preparation of the intermediate layer film is 270°C (Tm+50°C, Tm is the melting point of PA6 granules), and the remaining steps are consistent with Example 1.

[0123] Example 8

[0124] The difference from Example 1 is that during the pre-solid forming process, the first layer is then heated using a non-contact infrared heating plate, and the heating temperature is 280°C (i.e. Tm1+50°C, Tm1 is the melting point of CF / PA6 plate-1), and the remaining steps are consistent with Example 1.

[0125] Example 9

[0126] The difference from Example 1 is that during the pre-solid forming process, the mold is heated to 200°C (i.e. higher than the general curing temperature), and the remaining steps are consistent with Example 1.

[0127] Example 10

[0128] The difference from Example 1 is that the composite blank is not subjected to vacuum treatment, and the remaining steps are consistent with Example 1.

[0129] Example 11

[0130] The difference from Example 1 is that the composite blank is not subjected to freezing treatment, and the remaining steps are consistent with Example 1.

[0131] Comparative Example 1

[0132] The first layer and the intermediate layer film are consistent with Example 1, and the difference between this comparative example and Example 1 is that the second layer does not use a prepreg material, which is as follows:

[0133] The T300 carbon fiber twill woven cloth, the intermediate layer film, and the first layer blank are stacked and laid in the order of top, middle, and bottom through a positioning tool, and epoxy resin is applied on the T300 carbon fiber twill woven cloth to form a composite blank, and the remaining steps and parameters are consistent with Example 1.

[0134] Comparative Example 2

[0135] The difference from Example 1 is that there is no intermediate layer material, and the remaining steps are consistent with Example 1.

[0136] Test Example 1

[0137] The carbon fiber composite structures prepared in Examples 1-11 and Comparative Examples 1-2 were subjected to appearance quality detection. The detection method was visual inspection, i.e., at least 5 trained evaluators visually inspected the continuity and regularity of the fiber lines and scored them on a percentage scale, and the average value was taken as the final regularity.

[0138] The test results showed that the carbon fiber composite structures prepared in the present application had high fiber line regularity, which could reach more than 95%. The specific appearance is shown in FIGS. 1-11 and FIGS. 13-14. Figure 4 and FIGS. 13-14. Figure 5 Comparative Example 1 did not use prepreg to prepare the composite structure, and the fiber lines formed were disordered and had poor appearance. The specific appearance is shown in FIGS. 12 and 15. Figure 5 This is mainly because the carbon fiber thermosetting prepreg is used as one of the surface layers of the composite structure in the preparation process of the present application. During co-curing molding, the use of prepreg significantly reduces the fiber disorder caused by the flow of thermoplastic materials under pressure, thereby significantly improving the high regularity of the fiber lines. In the application process, this surface layer can serve as the outer layer of the component, has excellent appearance, and meets higher aesthetic requirements.

[0139] Test Example 2

[0140] The carbon fiber composite structures prepared in Examples 1-11 and Comparative Examples 1-2 were subjected to performance detection. The specific detection indexes included bending strength, impact resistance, interlaminar shear strength, and interfacial peeling strength. The specific test methods were as follows:

[0141] (1) Bending strength: tested according to the GB / T 1449-2005 standard.

[0142] (2) Impact resistance: tested according to the GB / T 1451-2005 standard.

[0143] (3) Interlaminar shear strength: tested according to the GB / T 1450.1-2005 standard.

[0144] (4) Interfacial peeling strength: tested according to the ASTM D3167-10(2023) standard.

[0145] The results measured according to the above test methods are shown in Table 1:

[0146] Table 1: Performance test results of carbon fiber composite structures

[0147]

[0148] As can be seen from the results of Table 1, the carbon fiber composite structure prepared in the embodiments of the present application has excellent comprehensive mechanical properties, while the carbon fiber composite structure prepared in Comparative Example 2 has poor interfacial peeling strength, and as can be seen from the results of Test Example 1, the composite structure prepared in Comparative Example 1 has poor apparent morphology. Therefore, by using the carbon fiber thermosetting prepreg, the intermediate layer material and the first carbon fiber thermoplastic material for co-curing, the present application prepares a composite structure including at least three layers, the interface performance between the layers of the composite structure is excellent, the interface strength is high, and in particular, the intermediate layer material is used to promote the close combination between the heterogeneous materials, to form a strong molecular level interface combination, to realize the preparation of a carbon fiber composite structure with high quality surface and high mechanical properties.

[0149] The technical features of the above-described embodiments can be combined in any manner. To make the description concise, all possible combinations of the technical features in the above-described embodiments are not described, but as long as the combinations of the technical features do not contradict each other, they should be considered within the scope of the present disclosure.

[0150] The above-described embodiments only express several embodiments of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of the present application. Therefore, the scope of protection of the present application should be subject to the appended claims.

Claims

1. A carbon fiber composite structure, characterized by, The carbon fiber composite structure is formed by co-curing the first layer, the intermediate layer and the second layer in sequence; the material of the first layer comprises a first carbon fiber thermoplastic material, the material of the intermediate layer comprises a thermoplastic material and a coupling agent, and the material of the second layer comprises a carbon fiber thermosetting prepreg.

2. The carbon fiber composite structure of claim 1, wherein, The thermoplastic resin in the first carbon fiber thermoplastic material comprises one or more of polyamide, polypropylene, and polycarbonate; and / or, the volume fraction of carbon fibers in the first carbon fiber thermoplastic material is 45%-60%; and / or, the mass ratio of the coupling agent to the thermoplastic material is (0.5-5): 100; and / or, the coupling agent comprises one or more of γ-glycidoxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and γ-methacryloyloxypropyltrimethoxysilane; and / or, the thermosetting resin in the carbon fiber thermosetting prepreg comprises one or more of epoxy resin and phenolic resin; and / or, the volume fraction of carbon fibers in the carbon fiber thermosetting prepreg is 60%-80%; and / or, the areal density of the carbon fiber thermosetting prepreg is 100 g / m 2 -400 g / m 2 ; and / or, the thickness of the first layer is 1 mm-2 mm; and / or, the thickness of the intermediate layer is 0.1 mm-1 mm; and / or, the thickness of the second layer is 0.2 mm-1 mm.

3. The carbon fiber composite structure according to claim 1 or 2, characterized in that, The carbon fiber composite structure further comprises a reinforcing layer connected to the surface of the first layer; the material of the reinforcing layer comprises a second carbon fiber thermoplastic material, the second carbon fiber thermoplastic material comprises a chopped carbon fiber thermoplastic material, and the thermoplastic resin in the second carbon fiber thermoplastic material comprises one or more of polyamide, polypropylene and polycarbonate.

4. A method for producing a carbon fiber composite structure, characterized by, The method comprises the following steps: The material of the first layer is subjected to a first heat treatment to form the first layer by first die pressing; the material of the first layer comprises a first carbon fiber thermoplastic material; The material of the intermediate layer is formed into the intermediate layer by second die pressing; the material of the intermediate layer comprises a thermoplastic material and a coupling agent; The first layer, the intermediate layer and the second layer are stacked in sequence to form a composite blank, the composite blank is subjected to vacuumizing and freezing treatment to form a pre-solid; the material of the second layer comprises a carbon fiber thermosetting prepreg; The pre-solid is co-cured to form a carbon fiber composite structure; during the co-curing process, the pre-solid is subjected to a second heat treatment and a third die pressing treatment.

5. The preparation method of the carbon fiber composite structure according to claim 4, characterized in that, The first heat treatment is non-contact infrared heating; and / or, the second heat treatment comprises non-contact infrared heating of the first layer and contact heating of the second layer; And / or, The temperature of the first heat treatment is (Tm1+10℃) to (Tm1+30℃), and Tm1 is the melting point of the first carbon fiber thermoplastic material; and / or, during the second heat treatment, the temperature of the non-contact infrared heating is (Tm1+10℃) to (Tm1+30℃), and Tm1 is the melting point of the first carbon fiber thermoplastic material; the temperature of the contact heating is 120℃-180℃; And / or, The processing time of the first heat treatment and the second heat treatment is independently 0.5min-5min; and / or, the applied pressure of the first die pressing, the second die pressing and the third die pressing is independently 5MPa-30MPa; and / or, the processing time of the first die pressing, the second die pressing and the third die pressing is independently 3min-10min.

6. The method of producing a carbon fiber composite structure according to claim 4, characterized by, The composite blank is vacuumized to <-0.095MPa; and / or, the temperature of the freezing treatment is 0℃ to -20℃.

7. The preparation method of the carbon fiber composite structure according to any one of claims 4 to 6, characterized in that, During the co-curing process, a step of injection molding the intermediate formed after the third die pressing by using the material of the reinforcing layer is further included; The material of the reinforcing layer comprises a second carbon fiber thermoplastic material, and the second carbon fiber thermoplastic material comprises a chopped carbon fiber thermoplastic material.

8. The method of producing a carbon fiber composite structure according to claim 7, characterized by, the temperature of the injection molding is (Tm2-30°C) to (Tm2+20°C), the Tm2 is the melting point of the material of the reinforcing layer; and / or, the pressure of the injection molding is 70 MPa-100 MPa; and / or, the speed of the injection molding is 50 cm 3 / s-80 cm 3 / s.

9. The method for preparing the carbon fiber composite structure according to claim 7, characterized in that, During the co-curing process, a curing treatment of the reinforced composite structure formed after the injection molding is further included, the curing temperature is 120℃-180℃, and the curing time is 10min-20min.

10. An integrated component, characterized by The integrated component is made of the carbon fiber composite structure according to any one of claims 1-3, or is made by the method according to any one of claims 4-9.

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