Carbon fiber prepreg, preparation method thereof and carbon fiber composite material

Abstract

The invention discloses a carbon fiber prepreg, a preparation method thereof and a carbon fiber composite material, and relates to the technical field of advanced material compounding. The carbon fiber prepreg comprises a carbon fiber layer, a first resin matrix and a second resin matrix, the carbon fiber layer is coated with the first resin matrix, and gaps in the carbon fiber layer are filled with the first resin matrix; the first resin matrix is coated with the second resin matrix, and the second resin matrix comprises toughening particles; carbon fiber monofilaments of the carbon fiber layer have preset diameters which are larger than or equal to a preset threshold value. The carbon fiber composite material prepared from the carbon fiber prepreg has excellent compression performance, and the impact resistance, durability and other performance of the composite material can be effectively improved.

Description

Technical Field

[0001] The present application relates to the field of advanced material composite technology, and particularly to a carbon fiber prepreg, a preparation method thereof, and a carbon fiber composite material. Background Art

[0002] A carbon fiber prepreg is a material impregnated with carbon fibers and a resin matrix, and is an intermediate for preparing a carbon fiber composite material (Carbon Fiber Reinforced Polymer, CFRP). The carbon fiber composite material can achieve an organic combination of lightweight and high-strength characteristics, making it an ideal application in many weight-sensitive industries such as aerospace, sports and leisure, national defense, automotive, and wind energy.

[0003] Compared with the tensile properties, the longitudinal compression properties of carbon fiber composite materials are poor, which greatly limits their wide application. Generally, the compressive strength of carbon fiber composite materials is only about 30% to 50% of their tensile strength. The decrease in compression properties is mainly controlled by the microstructure of carbon fibers. For composite materials, the compression properties are also extremely sensitive to factors such as manufacturing methods, laminate designs, and material properties. Therefore, this limitation in compression properties leads to design limitations, preventing structural components from fully utilizing the high performance of carbon fibers.

[0004] Synchronously, the damage characteristics of the laminate after drop-weight impact and its compression properties are one of the serious situations that must be considered in the damage tolerance design of composite material structures, and can be used to characterize the toughness of CFRP. Therefore, experimental studies on the impact damage of CFRP laminates and their compressive strength after impact (CAI) have always been the focus of many researchers.

[0005] In the past few decades, research on improving the properties of carbon fibers and their composite materials has increased explosively. Although concerns about the low compression properties of carbon fibers were raised thirty years ago, there has been no substantial progress in research on improving the corresponding compression properties to date. Summary of the Invention

[0006] To solve the above technical problems, the present application aims to provide a carbon fiber prepreg, a preparation method thereof, and a carbon fiber composite material. The carbon fiber composite material prepared from the carbon fiber prepreg has excellent compression properties.

[0007] According to the first aspect of the present application, there is provided a carbon fiber prepreg, the carbon fiber prepreg comprising a carbon fiber layer, a first resin matrix, and a second resin matrix;

[0008] The first resin matrix coats the carbon fiber layer and fills the gaps within the carbon fiber layer;

[0009] The second resin matrix coats the first resin matrix, and the second resin matrix includes toughening particles;

[0010] The carbon fiber filaments of the carbon fiber layer have a preset diameter, and the preset diameter is greater than or equal to a preset threshold.

[0011] In some embodiments of the present application, the mass of the toughening particles is 1.0-3.5% of the mass of the second resin matrix.

[0012] In some embodiments of the present application, the preset threshold is 5.1 μm;

[0013] The preset diameter is 5.1-5.4 μm.

[0014] In some embodiments of the present application, the mass of the carbon fiber layer is 62.5-69.5% of the mass of the carbon fiber prepreg.

[0015] According to a second aspect of the present application, there is provided a method for preparing a carbon fiber prepreg. The method for preparing the carbon fiber prepreg is used to prepare the carbon fiber prepreg as described in any one of the above, and the preparation method includes:

[0016] Arranging a carbon fiber bundle composed of a preset number of carbon fiber filaments according to a preset rule to obtain a carbon fiber layer;

[0017] Coating a first resin film on the surface of the carbon fiber layer, and infiltrating the carbon fiber layer with the first resin film under a first preset condition to obtain an intermediate material;

[0018] Coating a second resin film on the surface of the intermediate material, and infiltrating the intermediate material with the second resin film under a second preset condition to obtain the carbon fiber prepreg; wherein, the second resin film includes toughening particles.

[0019] In some embodiments of the present application, the ratio of the areal density of the first resin film to the areal density of the second resin film is 1.27-1.78:1.

[0020] In some embodiments of the present application, the areal density of the first resin film is 28-32 g / m 2 ;

[0021] The areal density of the second resin film is 18-22 g / m 2 ;

[0022] The areal density of the carbon fiber layer is 189-199 g / m 2 。

[0023] In some embodiments of the present application, the first preset condition includes: the impregnation temperature is 105-110 °C, and the impregnation pressure is 4.5-9.0 kg / cm;

[0024] The second preset condition includes: the impregnation temperature is 105 - 110 °C, and the impregnation pressure is 4.5 - 9.0 kg / cm².

[0025] According to the third aspect of the present application, a carbon fiber composite material is provided. The carbon fiber composite material is cured from the carbon fiber prepreg as described in any one of the above or the carbon fiber prepreg prepared by the preparation method of the carbon fiber prepreg as described in any one of the above.

[0026] In some embodiments of the present application, the 0° compression strength of the carbon fiber composite material is 1490 - 1685 MPa, and the compression strength after impact is 287 - 313 MPa.

[0027] The technical solutions provided by the present application may include the following beneficial effects:

[0028] In the present application, the carbon fiber layer is coated with the first resin matrix and filled into the gaps within the carbon fiber layer, which can isolate the carbon fiber layer from the toughening particles of the second resin matrix, effectively preventing the toughening particles from entering the gaps within the carbon fiber layer; and by adjusting the preset diameter of the carbon fiber filaments of the carbon fiber layer to be greater than or equal to the preset threshold, the compression performance of the composite material can be further improved.

[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] The drawings herein are incorporated into the specification and form a part of the specification, showing embodiments consistent with the present application, and are used together with the specification to explain the principles of the present application.

[0031] Figure 1 It is a schematic diagram of the layer structure of a two - film carbon fiber prepreg shown according to an exemplary embodiment.

[0032] Figure 2 It is a metallographic microscope image of a two - film carbon fiber composite material shown according to an exemplary embodiment.

[0033] Figure 3 It is a schematic diagram of the layer structure of a four - film carbon fiber prepreg shown according to an exemplary embodiment.

[0034] Figure 4 It is a metallographic microscope image of a four - film carbon fiber prepreg shown according to an exemplary embodiment.

[0035] Figure 5 It is a flowchart of the preparation method of the carbon fiber composite material shown according to an exemplary embodiment. BRIEF DESCRIPTION OF THE DRAWINGS:

[0037] 1. Carbon fiber layer; 2. First resin matrix; 3. Second resin matrix;

[0038] 1'. Fiber layer; 2'. Resin matrix. Specific embodiments

[0039] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the following will clearly and completely describe the technical solutions of this application in conjunction with the embodiments of this application and the accompanying drawings. Obviously, the described embodiments are some, but not all, of the embodiments of this application. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative efforts fall within the scope of protection of this application. It should be noted that, without conflict, the embodiments in this application and the features in the embodiments can be arbitrarily combined with each other.

[0040] To improve the toughness and impact resistance of carbon fiber composites, toughening particles can be added to the resin matrix to disperse stress and absorb impact energy, reduce the damage of impact to the material, delay or prevent the propagation of cracks, and improve the fracture toughness of the material. Currently, the autoclave molding process is mostly used. Under the action of a certain temperature and pressure, the carbon fiber prepreg is cured in a mold to form a composite material.

[0041] For example, when preparing a carbon fiber prepreg using the two-film method, resin films containing toughening particles are respectively attached to the upper and lower surfaces of the fiber layer 1', and then, under a certain temperature and pressure, the resin films are allowed to infiltrate the fiber layer 1' to obtain Figure 1 the carbon fiber prepreg as shown. The carbon fiber prepreg includes a fiber layer 1' and a resin matrix 2'. The resin matrix 2' coats the fiber layer 1' and fills the gaps inside the fiber layer 1'. The resin matrix 2' includes toughening particles.

[0042] However, in actual products, as Figure 2 shown, under the action of a certain pressure, the toughening particles ( Figure 2 the black areas in) will enter the interior of the fiber layer 1' ( Figure 2 the white areas in), damaging the original structure of the fiber layer 1'. The toughening particles entering the fiber layer 1' form defects, affecting the straightness of the fibers, and resulting in a significant reduction in the 0° compressive strength of the composite material. At the same time, the toughening particles entering the interior of the fiber layer 1' cannot play their toughening role, leading to a significant reduction in the compressive strength after impact of the composite material.

[0043] Based on this, the present application provides a carbon fiber prepreg, which includes a carbon fiber layer, a first resin matrix, and a second resin matrix; the first resin matrix coats the carbon fiber layer and fills the gaps within the carbon fiber layer; the second resin matrix coats the first resin matrix, and the second resin matrix includes toughening particles; the carbon fiber filaments of the carbon fiber layer have a preset diameter, and the preset diameter is greater than or equal to a preset threshold. By coating the carbon fiber layer with the first resin matrix and filling the gaps within the carbon fiber layer, it can play a role in isolating the carbon fiber layer from the toughening particles of the second resin matrix, effectively preventing the toughening particles from entering the gaps within the carbon fiber layer; moreover, by adjusting the preset diameter of the carbon fiber filaments of the carbon fiber layer to be greater than or equal to the preset threshold, the compression performance of the composite material can be further improved.

[0044] Some specific embodiments described below are intended to facilitate the understanding of those skilled in the art of this embodiment, and this embodiment is not limited to some specific embodiments described below.

[0045] In an exemplary embodiment, as Figure 3 shown, the present application provides a carbon fiber prepreg, which includes a carbon fiber layer 1, a first resin matrix 2, and a second resin matrix 3; the first resin matrix 2 coats the carbon fiber layer 1 and fills the gaps within the carbon fiber layer 1; the second resin matrix 3 coats the first resin matrix 2, and the second resin matrix 3 includes toughening particles; the carbon fiber filaments of the carbon fiber layer 1 have a preset diameter, and the preset diameter is greater than or equal to a preset threshold.

[0046] In this embodiment, by coating the carbon fiber layer 1 with the first resin matrix 2 and filling the gaps within the carbon fiber layer 1, it can play a role in isolating the carbon fiber layer 1 from the toughening particles of the second resin matrix 3, effectively preventing the toughening particles from entering the gaps within the carbon fiber layer 1; as Figure 4 shown, the carbon fiber layer 1 ( Figure 4 the white area in) has good continuity, indicating that the toughening particles have not entered the carbon fiber layer 1 and have not damaged the structure of the carbon fiber layer 1. Moreover, by adjusting the preset diameter of the carbon fiber filaments of the carbon fiber layer 1 to be greater than or equal to the preset threshold, the compression performance of the composite material can be further improved. Among them, both the first resin matrix 2 and the second resin matrix 3 can be epoxy resin systems, and the toughening particles can be PES (polyethersulfone) toughening particles.

[0047] In an exemplary embodiment, the mass of the toughening particles is 1.0 - 3.5% of the mass of the second resin matrix 3.

[0048] The toughening particles formed by an appropriate amount of toughening particles can effectively absorb and disperse stress, delay or prevent the expansion of cracks, and improve the toughness and impact resistance of the composite material; however, excessive toughening particles will also enter the gaps in the carbon fiber layer 1, destroying the structure of the carbon fiber layer 1 itself, resulting in a decrease in the strength of the composite material. Therefore, in this embodiment, when the mass of the toughening particles is 1.0-3.5% of the mass of the second resin matrix 3, the composite material can maintain good comprehensive performance.

[0049] Exemplarily, the mass of the toughening particles is 1.0%, 2.2%, 2.8%, 3.0%, 3.5% of the mass of the second resin matrix 3. The mass percentage of the toughening particles to the mass of the second resin matrix 3 may also be any value between the exemplary mass percentages, for example, the mass of the toughening particles accounts for 2.2-3.0% of the mass of the second resin matrix 3.

[0050] In an exemplary embodiment, the preset threshold is 5.1 μm;

[0051] The preset diameter is 5.1-5.4μm.

[0052] Carbon fiber monofilament is the basic unit of carbon fiber. A carbon fiber bundle can be formed by multiple carbon fiber monofilaments, and a carbon fiber layer 1 can be formed by arranging the carbon fiber bundle according to a preset rule. For example, 12K carbon fiber means that each bundle of carbon fiber filaments contains 12,000 carbon fiber monofilaments. Among them, the diameter of the carbon fiber monofilament has an important influence on the mechanical properties of the composite material. Under normal circumstances, the strength of the small diameter carbon fiber monofilament is higher, which can improve the strength of the composite material; and the small diameter carbon fiber monofilament can absorb more energy when subjected to force to improve the toughness of the composite material; while the strength and toughness of the large diameter carbon fiber monofilament are relatively low. The carbon fiber in this embodiment can, for example, select domestic dry-jet wet-spinning T800 grade (SYT55S-12K) carbon fiber. The carbon fiber monofilament of the carbon fiber bundle includes two carbon fiber monofilaments, CCF-1 and CCF-2. The main difference between CCF-1 and CCF-2 is that the diameter of the fiber monofilament is different, and the other body properties are basically the same, wherein the diameter of the CCF-1 monofilament is 5.1μm, and the diameter of the CCF-2 monofilament is 5.4μm. By controlling the diameter of the fiber monofilament to 5.1-5.4 μm, the compression performance of the composite material can be improved.

[0053] In an exemplary embodiment, the mass of the carbon fiber layer 1 is 62.5-69.5% of the mass of the carbon fiber prepreg.

[0054] In this embodiment, controlling the percentage of the mass of the carbon fiber layer 1 in the mass of the carbon fiber prepreg to be 62.5 - 69.5% can endow the prepared composite material with good mechanical properties and processing properties. Exemplarily, the mass of the carbon fiber layer 1 is 62.5%, 64.7%, 66.8%, 68.0%, or 69.5% of the mass of the carbon fiber prepreg. The percentage of the mass of the carbon fiber layer 1 in the mass of the carbon fiber prepreg can also be any value between the exemplary ratios. For example, the percentage of the mass of the carbon fiber layer 1 in the mass of the carbon fiber prepreg can also be 64.7 - 66.8%.

[0055] As Figure 5 shown, an exemplary embodiment of the present application provides a method for preparing a carbon fiber prepreg. The method for preparing the carbon fiber prepreg is used to prepare the carbon fiber prepreg of any of the above embodiments. The preparation method includes:

[0056] S110. Arrange a carbon fiber bundle composed of a preset number of carbon fiber filaments according to a preset rule to obtain a carbon fiber layer.

[0057] In step S110, the specification of the carbon fiber bundle can be selected according to the product performance. For example, a carbon fiber bundle composed of 12,000 carbon fiber filaments is a 12K carbon fiber, a carbon fiber bundle composed of 24,000 carbon fiber filaments is a 24K carbon fiber, and a carbon fiber bundle composed of 36,000 carbon fiber filaments is a 36K carbon fiber.

[0058] The preset rule for arranging the carbon fiber bundles can be unidirectional arrangement, that is, all fiber bundles are arranged in parallel (0° direction), or bidirectional arrangement, that is, the fiber bundles are arranged in an orthogonal form (such as 0° and 90°), or laid and laminated at multiple angles (such as [0° / ±45° / 90°]).

[0059] S120. Cover a first resin film on the surface of the carbon fiber layer, and infiltrate the carbon fiber layer with the first resin film under a first preset condition to obtain an intermediate material.

[0060] In step S120, the first resin film is respectively attached to the upper surface and the lower surface of the carbon fiber layer 1, and the first resin film is infiltrated into the carbon fiber layer 1 under a first preset condition to form a first resin matrix 2 that coats and fills the internal gaps of the carbon fiber layer 1. Among them, the first resin film is coated with a first resin composition, and the coating temperature of the first resin composition is 78 - 82°C. For example, the coating temperature of the first resin composition can be 78°C, 80°C, or 82°C.

[0061] Exemplarily, the first resin composition may include raw materials in the following mass percentages: 62.5 - 68.7% of epoxy resin, 28.5 - 35.7% of curing agent, 0.5 - 2.0% of accelerator, and 0.5 - 2.0% of coupling agent. Among them, the epoxy resin may be one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, phenolic epoxy resin, and polyfunctional epoxy resin. For example, the epoxy resin includes bisphenol A epoxy resin and polyfunctional epoxy resin (tetraglycidylamine epoxy resin) with a weight ratio of 3.0 - 4.5:1; the curing agent may be one or more of triethylenetetramine and diethyltoluenediamine, etc.; the accelerator may be one or more of methyltetrahydrophthalic anhydride and 1-cyanoethyl-2-ethyl-4-methylimidazole, etc.; the coupling agent may be silane coupling agent KH550.

[0062] S130. Coating the second resin film on the surface of the intermediate material, and infiltrating the second resin film into the intermediate material under the second preset conditions to obtain a carbon fiber prepreg; wherein, the second resin film includes toughening particles.

[0063] In step S130, the second resin film is respectively attached to the upper surface and the lower surface of the intermediate material, and the second resin film is infiltrated into the intermediate material under the second preset conditions to form a second resin matrix 3 covering the intermediate material. Among them, the second resin film is formed by coating with the second resin composition, and the coating temperature of the second resin composition is 83 - 87°C. For example, the coating temperature of the second resin composition may be 83°C, 85°C, or 87°C.

[0064] The main difference between the second resin composition and the first resin composition is that the second resin composition contains toughening particles. Exemplarily, the second resin composition may include raw materials in the following mass percentages: 61.5 - 68.7% of epoxy resin, 28.5 - 35.7% of curing agent, 1.0 - 3.5% of toughening particles, 0.5 - 2.0% of accelerator, and 0.5 - 2.0% of coupling agent.

[0065] In an exemplary embodiment, the ratio of the areal density of the first resin film to that of the second resin film is 1.27 - 1.78:1.

[0066] In this embodiment, the carbon fiber prepreg is prepared by a four-film method, that is, the first resin film is first applied to the upper surface and the lower surface of the carbon fiber layer 1, and then the second resin film is applied; and the ratio of the surface density of the first resin film to the second resin film is controlled to be 1.27-1.78:1. Through the isolation effect of the first resin film, the toughening particles in the second resin film can be effectively prevented from entering the gap in the carbon fiber layer 1, so as to improve the integrity of the overall structure of the carbon fiber layer 1. Exemplarily, the ratio of the surface density of the first resin film to the second resin film can be 1.27:1, 1.38:1, 1.53:1, 1.65:1, 1.78:1. The ratio of the surface density of the first resin film to the second resin film can also be any value between the exemplary ratios, for example, the ratio of the surface density of the first resin film to the second resin film can also be any value between 1.32-1.55:1.

[0067] In an exemplary embodiment, the surface density of the first resin film is 28-32 g / m 2 ;

[0068] The surface density of the second resin film is 18-22 g / m 2 ;

[0069] The surface density of the carbon fiber layer 1 is 189-199 g / m 2 .

[0070] In this embodiment, the surface density of the first resin film, the second resin film and the carbon fiber layer 1 needs to be controlled within an appropriate range so that the first resin film and the second resin film can fully infiltrate the carbon fiber layer 1, reduce pores, and improve the mechanical properties of the composite material. For example, the surface density of the first resin film can be 28g / m 2 , 30g / m 2 , 32g / m 2 The surface density of the second resin film can be 18g / m 2 , 20g / m 2 , 22g / m 2 The surface density of the carbon fiber layer 1 can be 189 g / m 2 , 192g / m 2 , 194g / m 2 , 196g / m 2 , 199g / m 2 The surface density of the carbon fiber layer 1 may also be any value between the exemplary surface density values, for example, the surface density of the carbon fiber layer 1 may also be 192-196 g / m 2 Any value between .

[0071] In an exemplary embodiment, the first preset conditions include: an impregnation temperature of 105-110° C., an impregnation pressure of 4.5-9.0 kg / cm ;

[0072] The second preset condition includes: the impregnation temperature is 105 - 110 °C, and the impregnation pressure is 4.5 - 9.0 kg / cm².

[0073] In this embodiment, by controlling the impregnation temperature and pressure of the first preset condition and the second preset condition, it is possible to avoid the toughening particles in the second resin film from entering the gaps of the carbon fiber layer 1 while ensuring the impregnation effect, effectively improving the compression performance of the composite material. Among them, the first preset condition and the second preset condition can be the same or different.

[0074] Exemplarily, in one embodiment, the first preset condition includes: the impregnation temperature is 105 °C, and the impregnation pressure is 9.0 kg / cm²;

[0075] The second preset condition includes: the impregnation temperature is 105 °C, and the impregnation pressure is 9.0 kg / cm².

[0076] In another embodiment, the first preset condition includes: the impregnation temperature is 110 °C, and the impregnation pressure is 4.5 kg / cm²;

[0077] The second preset condition includes: the impregnation temperature is 107 °C, and the impregnation pressure is 6.8 kg / cm².

[0078] In another embodiment, the first preset condition includes: the impregnation temperature is 108 °C, and the impregnation pressure is 7.0 kg / cm²;

[0079] The second preset condition includes: the impregnation temperature is 110 °C, and the impregnation pressure is 4.5 kg / cm².

[0080] An exemplary embodiment of the present application provides a carbon fiber composite material, which is cured from a carbon fiber prepreg of any one of the above embodiments or a carbon fiber prepreg prepared by the preparation method of any one of the above embodiments of the carbon fiber prepreg.

[0081] In this embodiment, the carbon fiber composite material can be cured from one carbon fiber prepreg, or can also be cured from multiple carbon fiber prepregs stacked in a certain regular arrangement. The carbon fiber composite material can be prepared by a autoclave molding process, and its preparation method includes the following steps:

[0082] ① Clean the mold with a soft material, and then apply a release agent on the mold;

[0083] ② Use a prepreg cutting machine to cut the carbon fiber prepreg into an appropriate number of sheets, and then stack the layers according to the corresponding test standards to form a preform;

[0084] ③ After the prefabricated composite material blanks are combined and bagged, heating and pressure curing are carried out according to the curing process of the resin system. The curing process is to evacuate at room temperature, and the vacuum in the vacuum bag is -0.095 to -0.099 MPa; start pressurizing at room temperature, and pressurize to 0.6 MPa at a rate of 0.02 MPa / min; then heat up to 180 °C at a rate of 1.5 °C / min and keep the pressure for 120 min. Finally, cool down the pressure to below 60 °C at a rate of 2.0 °C / min and release the pressure out of the tank.

[0085] In an exemplary embodiment, the 0° compressive strength of the carbon fiber composite material is 1490 - 1685 MPa, and the compressive strength after impact is 287 - 313 MPa.

[0086] In this embodiment, the 0° compressive strength of the carbon fiber composite material can reach 1490 - 1685 MPa, and the compressive strength after impact can reach 287 - 313 MPa, indicating that the carbon fiber composite material has excellent compressive properties.

[0087] In order to more clearly explain the technical solution of the present application, specific embodiments of carbon fiber prepreg and carbon fiber composite material are listed in the present application. The beneficial effects of selecting the above ranges of the contents of each component and process parameters will be illustrated by specific experimental data through specific embodiments.

[0088] Example

[0089] It should be noted that, unless otherwise specified, the raw materials in the following examples can be obtained commercially.

[0090] Among them, both the first resin composition and the second resin composition are epoxy resin systems, and their formulations are basically the same. The main difference is that the first resin composition does not contain toughening particles, while the second resin composition contains toughening particles.

[0091] The diameter of the carbon fiber monofilament of CCF-1 is 5.1 μm, and the diameter of the carbon fiber monofilament of CCF-2 is 5.4 μm.

[0092] Example 1: A preparation method of a carbon fiber composite material, comprising the following steps:

[0093] (1) Pour the first resin composition and the second resin composition into the glue tanks of the film laminating machine respectively, adjust the film making process parameters, and uniformly transfer the first resin composition and the second resin composition onto the release paper respectively. After cooling, laminating and winding, the first resin film and the second resin film are obtained respectively. Among them, the coating temperature of the first resin composition is 80 °C, and the surface density of the first resin film is 30 g / m 2 ; the coating temperature of the second resin composition is 85 °C, and the surface density of the second resin film is 20 g / m 2 .

[0094] (2) The carbon fiber bundle is placed on the yarn rack and placed on the yarn shaft. After being pulled by the yarn guide hole, unfolded by the yarn dividing grate, and preheated and flattened by the flattening roller, the carbon fiber layer is put into the impregnation composite equipment; wherein the carbon fiber bundle is CCF-2, and the surface density of the carbon fiber layer is 194g / m 2 .

[0095] (3) applying a first resin film to the upper and lower surfaces of the carbon fiber layer, and allowing the first resin film to impregnate the carbon fiber layer under a first preset condition to obtain an intermediate material. Applying a second resin film to the surface of the intermediate material, and allowing the second resin film to impregnate the intermediate material under a second preset condition to obtain a carbon fiber prepreg.

[0096] The first resin film forms a first resin matrix, which covers the carbon fiber layer and fills the gaps in the carbon fiber layer; the second resin film forms a second resin matrix, which covers the first resin matrix, and the second resin matrix includes a toughening particle layer, and the mass of the toughening particle layer is 2.0% of the mass of the second resin matrix.

[0097] Among them, the first preset condition includes: the impregnation temperature is 108°C, the impregnation pressure is 7.5kg / cm; the second preset condition includes: the impregnation temperature is 108°C, the impregnation pressure is 7.5kg / cm; the mass of the carbon fiber layer in the carbon fiber prepreg is 66.0% of the mass of the carbon fiber prepreg.

[0098] (4) Clean the mold with a soft material and then apply a release agent on the mold; use a prepreg cutter to cut the carbon fiber prepreg into a suitable number of sheets, and then stack them in layers according to the corresponding test standards to form a preform; after the preform composite material blanks are assembled and bagged, they are cured by heating and pressurizing according to the curing process of the resin system. The curing process is vacuuming at room temperature, and the vacuum in the vacuum bag is -0.095 to -0.099 MPa; start pressurization at room temperature and pressurize to 0.6 MPa at a rate of 0.02 MPa / min; then heat to 180°C at a rate of 1.5°C / min, keep the temperature and pressure for 120 minutes, and finally cool to below 60°C at a rate of 2.0°C / min, and then release the pressure and take it out of the tank.

[0099] In order to more clearly explain the technical solution of the present application, the present application also lists Examples 2-6 of carbon fiber composite materials, wherein the process parameters of Examples 2-6 are shown in Table 1.

[0100] Table 1 shows a specific embodiment of the carbon fiber composite material in the present application. It should be noted that, except for the parameters listed in Table 1, other parameters of Examples 2-6 are substantially the same as those of Example 1.

[0101] In Table 1, the ratio C1 is the percentage of the mass of the toughening particle layer to the mass of the second resin matrix;

[0102] The ratio C2 is the percentage of the mass of the carbon fiber layer in the mass of the carbon fiber prepreg;

[0103] The ratio C3 is the ratio of the areal density of the first resin film to that of the second resin film.

[0104] Table 1 Process parameter table of the carbon fiber composite material of the examples

[0105]

[0106] Comparative example

[0107] Comparative example 1: The main difference between this comparative example and Example 1 lies in step (3). The two-film method is used to prepare the carbon fiber prepreg, and the specific steps are as follows:

[0108] The third resin film is covered on the upper and lower surfaces of the carbon fiber layer, and the third resin film is infiltrated into the carbon fiber layer under the first preset conditions to obtain the carbon fiber prepreg. Among them, the third resin film is coated with the first resin composition, and the areal density of the third resin film is (50±1) g / m 2 .

[0109] Comparative example 2:

[0110] The main differences between this comparative example and Example 1 lie in step (2) and step (3). CCF-2 in step (2) is replaced by CCF-1, and the two-film method is used to prepare the carbon fiber prepreg in step (3). The specific steps are as follows:

[0111] The third resin film is covered on the upper and lower surfaces of the carbon fiber layer, and the third resin film is infiltrated into the carbon fiber layer under the first preset conditions to obtain the carbon fiber prepreg. Among them, the third resin film is coated with the first resin composition, and the areal density of the third resin film is (50±1) g / m 2 .

[0112] Performance test

[0113] The carbon fiber composite laminates prepared by the methods of the examples and comparative examples are tested for compressive properties. Among them, the 0° compressive strength (0CS) test is carried out according to the SACMA 1R-94 standard, and the compressive strength after impact (CAI) test is carried out according to the ASTM D7136 / 7137 standard. The test conditions are 23°C / 50% RH; the test results are recorded in Table 2.

[0114] Table 2 Performance test table of the carbon fiber composite laminates of the examples and comparative examples

[0115] 0CS / MPa CAI / MPa Example 1 1685 310 Example 2 1549 299 Example 3 1520 287 Example 4 1563 295 Example 5 1490 305 Example 6 1647 313 Comparative Example 1 1364 263 Comparative Example 2 1207 252

[0116] As can be seen from Table 1 and Table 2, the carbon fiber composite material in the embodiment has excellent 0° compressive strength and compressive strength after impact. Among them, the 0° compressive strength of Example 1 reaches 1685 MPa, and the compressive strength after impact reaches 310 MPa, indicating that it has more excellent compressive performance.

[0117] As can be seen by combining Example 1 and Comparative Example 1, the 0° compressive strength of the composite material in Example 1 is increased by 24%, and the CAI is increased by 18%. It shows that during the impregnation process, as Figure 2 shown, when preparing the carbon fiber prepreg by the two-film method of Comparative Example 1, it is easy to cause the toughening particles to enter the inside of the fiber layer, damage the structure of the fiber layer itself, the particles entering the fiber layer form defects, affect the fiber straightness, and significantly reduce the 0° compressive strength; at the same time, the toughening particles entering the fiber layer cannot fully play the toughening role, and significantly reduce the compressive strength after impact.

[0118] As can be seen by combining Example 1 and Example 2, the 0° compressive strength of the composite material in Example 1 is increased by 8.8%, and the CAI is increased by 3.7%. It shows that when other parameters are the same, when the diameter of the carbon fiber monofilament increases, it is beneficial to improve the compressive performance of the composite material.

[0119] As can be seen by combining Examples 1-6, when the percentage of the mass of the toughening particle layer in the mass of the second resin matrix, the percentage of the mass of the carbon fiber layer in the mass of the carbon fiber prepreg, and the ratio of the surface density of the first resin film to the second resin film change, it will have different degrees of influence on the performance of the composite material. Among them, Example 1 and Example 6 have higher 0° compressive strength and CAI, indicating that when the ratio C1 is 2.0-3.5%, the ratio C2 is 66.0-69.5%, and the ratio C3 is 1.27-1.50:1, the composite material can have more excellent compressive performance.

[0120] It should be noted that in this article, the term "including", "comprising" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device.

[0121] The above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit them. Although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A carbon fiber prepreg, characterized in that, The carbon fiber prepreg includes a carbon fiber layer, a first resin matrix, and a second resin matrix; The first resin matrix coats the carbon fiber layer and fills the gaps within the carbon fiber layer; The second resin matrix coats the first resin matrix, and the second resin matrix includes toughening particles; The carbon fiber filaments of the carbon fiber layer have a preset diameter, and the preset diameter is greater than or equal to a preset threshold.

2. The carbon fiber prepreg according to claim 1, wherein, The mass of the toughening particles is 1.0 - 3.5% of the mass of the second resin matrix.

3. The carbon fiber prepreg according to claim 1, characterized in that The preset threshold is 5.1 μm; The preset diameter is 5.1 - 5.4 μm.

4. The carbon fiber prepreg according to claim 1, wherein The mass of the carbon fiber layer is 62.5 - 69.5% of the mass of the carbon fiber prepreg.

5. A preparation method of carbon fiber prepreg, characterized in that, The method for preparing the carbon fiber prepreg is used to prepare the carbon fiber prepreg according to any one of claims 1 - 4. The preparation method includes: Arranging carbon fiber bundles composed of a preset number of carbon fiber filaments according to a preset rule to obtain a carbon fiber layer; Covering a first resin film on the surface of the carbon fiber layer, and infiltrating the carbon fiber layer with the first resin film under a first preset condition to obtain an intermediate material; Covering a second resin film on the surface of the intermediate material, and infiltrating the intermediate material with the second resin film under a second preset condition to obtain the carbon fiber prepreg; wherein, the second resin film includes toughening particles.

6. The method for preparing the carbon fiber prepreg according to claim 5, wherein, The ratio of the areal density of the first resin film to that of the second resin film is 1.27 - 1.78:

1.

7. The method for preparing the carbon fiber prepreg according to claim 5, wherein The areal density of the first resin film is 28-32 g / m 2 ; The areal density of the second resin film is 18 - 22 g / m 2 ; The areal density of the carbon fiber layer is 189-199 g / m 2 .

8. The method for preparing the carbon fiber prepreg according to claim 5, wherein The first preset condition includes: an impregnation temperature of 105 - 110°C and an impregnation pressure of 4.5 - 9.0 kg / cm; The second preset condition includes: an impregnation temperature of 105 - 110°C and an impregnation pressure of 4.5 - 9.0 kg / cm.

9. A carbon fiber composite material, characterized in that, The carbon fiber composite material is cured from the carbon fiber prepreg according to any one of claims 1 - 4 or the carbon fiber prepreg prepared by the method for preparing the carbon fiber prepreg according to any one of claims 5 - 8.

10. The carbon fiber composite material according to claim 9, wherein, The 0° compression strength of the carbon fiber composite material is 1490 - 1685 MPa, and the compression strength after impact is 287 - 313 MPa.

Images