Preparation method and processing system of carbon fiber reinforced thermoplastic composite material and carbon fiber reinforced thermoplastic composite material

Abstract

The invention relates to a preparation method and a processing system of a carbon fiber reinforced thermoplastic composite material and the carbon fiber reinforced thermoplastic composite material. The preparation method comprises the following steps: sequentially carrying out suspension impregnation, pre-melting and high-temperature pultrusion on carbon fibers. The preparation method of the carbon fiber reinforced thermoplastic composite material provided by the invention is suitable for an automatic laying forming process, and by optimizing the process steps and process parameters of a powder suspension method, defect control in the preparation process can be realized, and the surface quality and mechanical properties of a product are improved.

Description

Technical Field

[0001] This invention relates to the field of composite material processing technology, and in particular to a method for preparing carbon fiber reinforced thermoplastic composite material, a processing system, and the carbon fiber reinforced thermoplastic composite material. Background Technology

[0002] Compared with traditional thermosetting resin composites, thermoplastic resin composites have advantages such as high melting point, short molding cycle, strong impact toughness, easy recycling and reuse, long shelf life of prepregs, and high production efficiency, and have a wide range of applications in the field of composite materials.

[0003] In composite material processing methods, automated layup molding, through highly digitalized and automated means, enables in-situ forming of parts during the processing. This method significantly improves the manufacturing efficiency and reduces the manufacturing cost of composite materials. In the field of automated layup molding technology for thermoplastic resins, although automated layup processes can greatly improve the layup efficiency of thermoplastic composites, significant challenges remain: at faster layup speeds, rapid heating and pressurization processes lead to insufficient interlayer contact. Simultaneously, due to the high melt viscosity of thermoplastic composites, the thermoplastic resin matrix cannot fully flow and entangle between layers in a short time, thus failing to form effective interlayer bonding. This ultimately results in manufacturing defects such as wrinkles, gaps, and overlaps, severely affecting the mechanical properties of the composite material.

[0004] Most thermoplastic composites suitable for automated lay-up molding are made from prepregs, and generally employ melt impregnation, solution impregnation, and suspension impregnation methods.

[0005] Melt impregnation involves continuously passing reinforcing fibers and molten thermoplastic resin through a pre-impregnation device, where the resin directly impregnates the fibers, thus obtaining a composite prepreg. CN105904611A discloses an ultra-thin continuous fiber-reinforced thermoplastic resin prepreg and its preparation method. This patent thins the continuous fibers and passes them through an impregnation die with a straight flow channel to achieve resin coating. However, melt impregnation requires high resin viscosity and good resin flowability during processing. Furthermore, the resin's long-term exposure to a high-temperature molten state significantly increases the likelihood of degradation, negatively impacting the performance of the prepared composite material.

[0006] Solution impregnation involves completely dissolving the matrix resin in a solvent to form a solution, then passing the fiber bundle through an impregnation tank containing the matrix resin solution, causing the fibers to become coated with resin. After sufficient impregnation, the solvent is removed, and the fibers are dried to obtain the prepreg. However, for resins such as PEEK and PPS (crystalline), there are no suitable low-boiling-point solvents that can dissolve them, making solution impregnation inconvenient. Furthermore, the use of solvents can cause significant environmental pollution.

[0007] The basic principle of the powder suspension method is to first mix resin powder with surfactants, solutions, or solvents to form a uniformly dispersed suspension. When the reinforcing fibers pass through the suspension, the resin powder will be adsorbed onto the surface of the reinforcing fibers under the action of the surfactant. Then, the additives are removed by heating in a high-temperature furnace, and the resin powder is melted and fully impregnated with the reinforcing fibers to form a whole. After cooling and shaping, a high-performance prepreg is obtained. CN111057346A discloses a carbon fiber reinforced PEEK unidirectional tape and its preparation method. Using polyetheretherketone (PEEK) resin as the matrix and carbon fiber as the reinforcing material, a carbon fiber reinforced PEEK unidirectional tape composite material is prepared. This solves the problem of resin refractory in the existing PEEK unidirectional tape preparation process, but certain challenges still exist in its application in the field of automated layup.

[0008] Existing thermoplastic composite prepreg preparation processes have poor applicability, are difficult to apply to subsequent automated lay-up molding processes, and are complex and costly to operate.

[0009] Therefore, how to provide a process-applicable method for preparing thermoplastic resin composites that is low-cost, highly efficient, and has controllable quality has become an urgent problem to be solved. Summary of the Invention

[0010] To address the aforementioned technical problems, this invention provides a method for preparing carbon fiber reinforced thermoplastic composites, a processing system, and the carbon fiber reinforced thermoplastic composite material itself. This preparation method is suitable for automated layup molding processes. By optimizing the process steps and parameters of the powder suspension method, defect control during the preparation process can be achieved, ensuring product quality and performance.

[0011] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides a method for preparing a carbon fiber reinforced thermoplastic composite material, the method comprising sequentially impregnating carbon fibers with a suspension, pre-melting, and high-temperature pultrusion.

[0012] The preparation method provided by the present invention includes sequentially impregnating carbon fibers with a suspension, pre-melting, and high-temperature pultrusion. The carbon fiber bundle is impregnated with a suspension to adsorb thermoplastic resin powder on its surface, and then pre-melting and high-temperature pultrusion are performed to achieve secondary melting and impregnation of thermoplastic resin powder, thereby improving the impregnation degree of thermoplastic resin.

[0013] Preferably, the number of carbon fiber bundles is 12-24 k, for example, 12 k, 14 k, 15 k, 16 k, 18 k, 20 k, 22 k or 24 k, etc.

[0014] Preferably, the temperature for impregnating the suspension is 25-45°C, for example, 25°C, 30°C, 35°C, 40°C, or 45°C.

[0015] Preferably, the suspension impregnation is performed under ultrasonic conditions.

[0016] Preferably, the frequency of the ultrasound is 10-50 Hz, for example, it can be 10 Hz, 20 Hz, 30 Hz, 40 Hz or 50 Hz.

[0017] Preferably, the pre-melting temperature is 300-500℃, for example, it can be 300℃, 320℃, 340℃, 350℃, 360℃, 380℃, 400℃, 420℃, 440℃, 450℃, 460℃, 480℃ or 500℃.

[0018] Preferably, the high-temperature pultrusion temperature is 350-500℃, for example, it can be 350℃, 360℃, 380℃, 400℃, 420℃, 440℃, 450℃, 460℃, 480℃ or 500℃, etc.

[0019] Preferably, the suspension impregnated by the suspension comprises, by mass percentage: 5-30% thermoplastic resin powder, 0.5-5% dispersant, 0.5-5% suspending agent, 0.5-5% thickener, 0.5-5% surfactant, and the balance being solvent.

[0020] Among them, 5-30% can be, for example, 5%, 10%, 15%, 20%, 25% or 30%; 0.5-5% can be, for example, 0.5%, 1%, 2%, 3%, 4% or 5%.

[0021] This invention uses a suspension for formulation design, providing a suspension solution in which thermoplastic resin powder is evenly dispersed, without agglomeration, and without the generation of a large amount of foam, thus ensuring the impregnation quality of the product.

[0022] The method for preparing the suspension provided by this invention includes the following steps: The components of the suspension are mixed to obtain the suspension.

[0023] Preferably, the mixing speed is 550-650 r / min, for example, it can be 550 r / min, 560 r / min, 580 r / min, 600 r / min, 620 r / min, 640 r / min or 650 r / min, etc.

[0024] Preferably, the mixing time is 10-20 h, for example, it can be 10 h, 12 h, 14 h, 15 h, 16 h, 18 h or 20 h.

[0025] Preferably, the mixing is carried out in the following order: solvent, dispersant, surfactant, thermoplastic resin powder, suspending agent and thickener.

[0026] The suspension dispersed better when mixed in the above order.

[0027] Preferably, the thermoplastic resin powder includes PEEK.

[0028] Preferably, the D50 particle size of the PEEK is 10-50 µm, for example, it can be 10 µm, 20 µm, 30 µm, 40 µm or 50 µm.

[0029] Preferably, the melting temperature of the PEEK is 300-350℃, for example, it can be 300℃, 310℃, 320℃, 330℃, 340℃ or 350℃.

[0030] Preferably, the dispersant comprises ethanol.

[0031] Preferably, the suspending agent comprises polyethylene glycol.

[0032] Preferably, the thickener comprises any one or a combination of at least two of polyvinyl alcohol, sodium polyacrylate, or polyacrylamide.

[0033] Preferably, the surfactant includes nonylphenol surfactants and / or fatty alcohol polyoxyethylene ether surfactants.

[0034] Preferably, the nonylphenol surfactant may be selected from any one or a combination of at least two of NP-6, NP-9 or NP-10.

[0035] Preferably, the fatty alcohol polyoxyethylene ether surfactant may be selected from AEO-7 and / or AEO-9.

[0036] Preferably, the solvent includes water.

[0037] Preferably, the preparation method of the carbon fiber reinforced thermoplastic composite material further includes unwinding, splitting, first yarn spreading, desizing and second yarn spreading in sequence before suspension impregnation, third yarn spreading between suspension impregnation and pre-melting, and hot roller extrusion, fourth yarn spreading and winding in sequence after high-temperature pultrusion.

[0038] This invention optimizes the preparation method of carbon fiber reinforced thermoplastic composites, including steps such as unwinding, filament splitting, yarn spreading, desizing, yarn spreading, suspension impregnation, yarn spreading, pre-melting, high-temperature pultrusion, hot roller extrusion, yarn spreading, and winding. First, the carbon fiber bundle is unwound and split. During processing, the carbon fiber remains within a closed-loop tension control system, and its state does not change drastically. During unwinding and filament splitting, each bundle of carbon fiber passes through a straightening comb, which forces precise positioning of each single filament. Subsequently, the fibers are allowed to wrap around all guide rollers at a reasonable angle to ensure stable contact and avoid sharp turns. After the carbon fiber tow is unwound, it undergoes desizing to remove the sizing agent from the carbon fiber surface. It is then unwound again to ensure there are no obvious gaps between the carbon fibers. Next, it is impregnated with a suspension to ensure that the suspension adheres evenly to the surface of the carbon fibers. Then, it is pre-melted and dried to remove moisture and other additives from the suspension except for the thermoplastic resin powder, and the thermoplastic resin powder is melted. Then, a second melting and impregnation of the thermoplastic resin powder is achieved through a high-temperature pultrusion device to improve the resin impregnation degree. Then, hot roller extrusion is used to improve the appearance quality of the carbon fiber reinforced thermoplastic composite material. Finally, it is unwound and wound to obtain the carbon fiber reinforced thermoplastic composite material.

[0039] Preferably, the unwinding tension is 10-30 kg / cm. 2 For example, it could be 10 kg / cm 2 15 kg / cm 2 20kg / cm 2 25 kg / cm 2 Or 30 kg / cm 2 wait.

[0040] Preferably, the winding tension is 20-30 kg / cm. 2 For example, it could be 20 kg / cm 2 22 kg / cm 2 24kg / cm 2 25 kg / cm 2 26 kg / cm 2 28 kg / cm 2 Or 30 kg / cm 2 wait.

[0041] Preferably, the desizing temperature is 400-550℃, for example, it can be 400℃, 420℃, 440℃, 450℃, 460℃, 480℃ or 500℃, etc.

[0042] Preferably, the temperature of the hot roller extrusion is 160-180℃, for example, it can be 160℃, 165℃, 170℃, 175℃ or 180℃.

[0043] Preferably, the pressure of the hot roller extrusion is 0.1-0.5 MPa, for example, it can be 0.1 MPa, 0.2 MPa, 0.3 MPa, 0.4 MPa or 0.5 MPa.

[0044] Preferably, the carbon fiber is subjected to unwinding, splitting, first unwinding, desizing, second unwinding, suspension impregnation, third unwinding, pre-melting, high-temperature pultrusion, hot roller extrusion, fourth unwinding, and winding in sequence.

[0045] Preferably, the traction speed is 0.3-2 m / min, for example, it can be 0.3 m / min, 0.5 m / min, 0.6 m / min, 0.8 m / min, 1 m / min, 1.2 m / min, 1.4 m / min, 1.5 m / min, 1.6 m / min, 1.8 m / min or 2 m / min, etc.

[0046] In the preparation method of carbon fiber reinforced thermoplastic composite material provided by the present invention, the traction rate mainly depends on the state of carbon fiber prepreg during the production process. When the processing system is initially set up, it runs at a speed of 0.3-1 m / min. After the product quality is stable, the speed is increased to 1-3 m / min. In the specific production process, the winding is started at this speed while ensuring product quality.

[0047] The greater the elastic modulus, width, and thickness of carbon fiber reinforced thermoplastic composites, the more manufacturing defects such as wrinkles, gaps, and overlaps there are, resulting in poorer layup quality during automated layup molding. This invention optimizes the parameters in the preparation method to adapt carbon fiber reinforced thermoplastic composites for automated layup molding. This is achieved by optimizing the fiber tension (winding and unwinding tension) and fiber travel speed (traction rate) to control the removal effect of the carbon fiber sizing agent and the melting state of the thermoplastic resin powder, thereby controlling the surface morphology of the carbon fiber reinforced thermoplastic composite. Furthermore, optimizing the content of thermoplastic resin powder and the fiber volume fraction in the suspension to avoid internal defects is crucial. Optimizing the pre-melting temperature controls the viscosity change of the thermoplastic resin. Finally, optimizing the temperature and pressure of the high-temperature pultrusion process (by adjusting the height of the upper and lower pultrusion dies) controls the wetting state between the thermoplastic resin and carbon fibers, enabling control over the width and thickness of the carbon fiber reinforced thermoplastic composite while ensuring the smoothness of the prepreg surface. Through optimization of the entire process, defect control and quality assurance of the carbon fiber reinforced thermoplastic composite are achieved, making it suitable for automated layup molding.

[0048] In a second aspect, the present invention provides a carbon fiber reinforced thermoplastic composite material processing system for implementing the preparation method of the carbon fiber reinforced thermoplastic composite material described in the first aspect, the carbon fiber reinforced thermoplastic composite material processing system comprising: a suspension impregnation device, a pre-melting device, and a high-temperature pultrusion device.

[0049] Preferably, the suspension impregnation device includes an impregnation tank and a first traction device disposed at the bottom of the impregnation tank.

[0050] Preferably, the first traction device is submerged in the suspension.

[0051] Preferably, the pre-melting device includes a pre-melting furnace.

[0052] Preferably, the high-temperature pultrusion apparatus includes a second traction device, an extrusion die, and a third traction device.

[0053] Preferably, the extrusion die has an upper die and a lower die arranged in parallel.

[0054] Preferably, the gap between the upper mold and the lower mold is 0.1-0.5 mm, for example, it can be 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm or 0.5 mm, etc.

[0055] Preferably, the carbon fiber reinforced thermoplastic composite material processing system further includes an unwinding and unwinding device and a desizing device arranged sequentially before the suspension impregnation system, and a hot roller extrusion device and a winding device arranged sequentially after the high-temperature pultrusion device.

[0056] Preferably, the unwinding and spreading device includes a yarn frame, a yarn separating comb, and a first spreading device arranged in sequence.

[0057] Preferably, the deslurry removal device includes an incinerator.

[0058] Preferably, a second yarn spreading device is provided between the desizing device and the suspension impregnation device.

[0059] Preferably, the second yarn spreading device includes a fourth traction device, a yarn spreading guide roller group, and a fifth traction device.

[0060] The second yarn-spreading device in this invention primarily functions to control the width of the unfolded fiber layer and increase the yarn width by adjusting the parameters of the guide rollers (such as rotation speed and angle) or using guide rollers of different specifications. Spreading the fiber bundle into a thin layer reduces its thickness and density. This allows the resin powder to penetrate more easily and quickly between each fiber during the subsequent suspension impregnation process, significantly reducing bubbles and dry spots and improving the product quality of the composite material. Furthermore, the guide rollers also guide and transport the fibers, maintaining stability in the production process.

[0061] Preferably, a third yarn spreading device is provided between the suspension impregnation device and the pre-melting device.

[0062] Preferably, the third yarn spreading device includes a guide roller group.

[0063] Preferably, the hot roller extrusion device includes a hot pressure roller assembly.

[0064] Preferably, the winding device includes a fourth yarn spreading device and a winding machine.

[0065] Preferably, the first yarn spreading device and the fourth yarn spreading device each independently include a guide roller group.

[0066] Preferably, the first traction device, the second traction device, the third traction device, the fourth traction device, and the fifth traction device each independently include a guide roller assembly.

[0067] This invention provides a carbon fiber reinforced thermoplastic composite material processing system for implementing the method for preparing carbon fiber reinforced thermoplastic composite materials as described in the first aspect. The carbon fiber is unwound from the yarn rack, unwound, and then sequentially passes through a threading hole, a filament comb, and a first yarn spreading device for filament separation and spreading. It is then desized in an incinerator, and the desized carbon fiber is spread a second time through a second yarn spreading device. The carbon fiber is then impregnated in a suspension in an impregnation tank by a traction device in the impregnation tank. After impregnation, it is drawn into a pre-melting furnace by a third yarn spreading device for drying and pre-melting. The dried and pre-melted carbon fiber is drawn to an extrusion die for high-temperature extrusion. After high-temperature extrusion, the carbon fiber is drawn to a hot roller group for hot roller extrusion. The hot roller extruded carbon fiber is drawn to a winding machine by a fourth yarn spreading device for winding.

[0068] During the traction process, fiber straightness is maintained as much as possible to reduce bending and twisting of carbon fibers, and to ensure that there is no significant interleaving or twisting between fiber bundles. During desizing, the removal effect of the sizing agent is monitored by observing the fiber spreading; ideally, there should be no obvious gaps between the carbon fibers. Once the spreading effect reaches the expected target, the impregnation tank temperature is raised to the set temperature, and the prepared suspension is poured into the impregnation tank. The carbon fibers are then impregnated with the suspension by traction, allowing resin powder to adhere. After impregnation, the carbon fibers pass through a pre-melting device to remove moisture and additives. Simultaneously, thermoplastic resin pre-melts and initially wets the carbon fibers before traction to a high-temperature extrusion device. The upper surface of the pultrusion die is pressed down, and pultrusion molding is performed under specific temperature and pressure conditions, resulting in a secondary melting and impregnation with thermoplastic resin powder.

[0069] Preferably, the carbon fiber reinforced thermoplastic composite material processing system is equipped with an edge position controller.

[0070] Preferably, the edge position controller is located between the desizing device and the suspension impregnation device.

[0071] Before entering the suspension impregnation device, the present invention can set an edge position controller to achieve active correction, ensure the straightness of the carbon fibers to reduce fiber bending and twisting, and avoid phenomena such as cross-linking and twisting between carbon fiber bundles.

[0072] Preferably, the carbon fiber reinforced thermoplastic composite material processing system is equipped with a centering device and / or an infrared detection device.

[0073] Preferably, the centering device and / or infrared detection device are located between the hot roll extrusion device and the winding device.

[0074] The present invention includes a centering device and an infrared detection device. The infrared device mainly uses an infrared light source and a receiver to detect the edge position of the carbon fiber reinforced thermoplastic composite material in real time and compares the position signal with a preset reference position. Once a deviation is detected, the actuator is driven to automatically correct it, thereby ensuring that the carbon fiber reinforced thermoplastic composite material always runs along the set path.

[0075] Thirdly, the present invention provides a carbon fiber reinforced thermoplastic composite material prepared by the method for preparing carbon fiber reinforced thermoplastic composite material as described in the first aspect.

[0076] Compared with the prior art, the present invention has at least the following beneficial effects: (1) The present invention uses the powder suspension method to prepare carbon fiber reinforced thermoplastic composite material. By optimizing the process steps and process parameters of the powder suspension method, the shortcomings of traditional methods such as melt impregnation in preparing prepreg are avoided, and the surface quality and mechanical properties of the prepared carbon fiber reinforced thermoplastic composite material are effectively guaranteed, which can meet the needs of aerospace and other fields for carbon fiber reinforced thermoplastic composite material.

[0077] (2) The carbon fiber reinforced thermoplastic composite material prepared by the present invention has a width of 66.72-74.89 mm, a thickness of 0.14-0.20 mm, a tensile strength of 1848-2725 MPa, an interlaminar shear strength of 88-115 MPa, a flexural strength of 1137-1752 MPa, and a compressive strength of 804-1070 MPa. Attached Figure Description

[0078] Figure 1 This is a process flow diagram of the preparation method of carbon fiber reinforced thermoplastic composite material provided by the present invention; Figure 2This is a system diagram of the apparatus for processing carbon fiber reinforced thermoplastic composite materials, which is provided in Embodiment 1 of the present invention to realize the preparation method of carbon fiber reinforced thermoplastic composite materials; Figure 3 This is a diagram of the apparatus system for processing carbon fiber reinforced thermoplastic composite materials, which is provided in Comparative Example 1 of the present invention to realize the preparation method of carbon fiber reinforced thermoplastic composite materials; Among them, 1-unwinding and spreading device, 101-yarn frame, 102-filament separating comb, 103-first spreading device; 2-Desizing device; 3-Second yarn spreading device, 301-Fourth traction device, 302-Yarn spreading guide roller group, 303-Fifth traction device; 4-Suspension impregnation device, 401-Impregnation tank, 402-First traction device; 5-Third yarn spreading device; 6-Pre-melting device; 7-High temperature pultrusion device, 701-Second traction device, 702-Upper die, 703-Lower die, 704-Third traction device; 8-Hot roller extrusion device; 9-Rewinding device, 901-Fourth yarn spreading device, 902-Rewinding machine; Figure 4 This is a metallographic micrograph of the carbon fiber reinforced thermoplastic composite material prepared in Example 1 of the present invention, with a scale bar of 10 μm; Figure 5 This is a metallographic micrograph of the carbon fiber reinforced thermoplastic composite material prepared in Comparative Application Example 1 of the present invention, with a scale bar of 10 μm. Detailed Implementation

[0079] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, the following examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0080] The specific information of the materials used in the following specific embodiments of the present invention is as follows: Carbon fiber A and carbon fiber TZ800 were purchased from Weihai Guangwei Composite Materials Co., Ltd. Carbon fiber B and carbon fiber TZ1000 were purchased from Weihai Guangwei Composite Materials Co., Ltd. PEEK, PF series - 550PF, purchased from Jilin Zhongyan Polymer Materials Co., Ltd. Dispersant, ethanol, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; Suspension agent, polyethylene glycol, purchased from Beijing Huawirui Chemical Technology Co., Ltd.; Thickener, sodium polyacrylate, purchased from Shanghai Bid Pharmaceutical Technology Co., Ltd.; Surfactant, fatty alcohol polyoxyethylene ether, purchased from Shanghai Yuanye Biotechnology Co., Ltd.

[0081] Example 1 This embodiment provides a processing system for carbon fiber reinforced thermoplastic composite materials, the processing system as follows: Figure 2 As shown, the device includes, in sequence, a yarn unwinding and spreading device 1 (including a yarn frame 101, a yarn separating comb 102, and a first yarn spreading device 103), a desizing device 2, a second yarn spreading device 3 (including a fourth traction device 301, a yarn spreading guide roller group 302, and a fifth traction device 303), a suspension impregnation device 4 (including an impregnation tank 401 and a first traction device 402), a third yarn spreading device 5, a pre-melting device 6, a high-temperature pultrusion device 7 (including a second traction device 701, an extrusion die (including an upper die 702 and a lower die 703 arranged in parallel), a third traction device 704), a hot roller extrusion device 8, and a winding device 9 (including a fourth yarn spreading device 901 and a winding machine 902).

[0082] Comparative Example 1 This comparative example provides a processing system for carbon fiber reinforced thermoplastic composite materials, including a yarn unwinding and spreading device 1 (including a yarn frame 101, a yarn splitting comb 102, and a first yarn spreading device 103), a desizing device 2, a second yarn spreading device 3 (including a fourth traction device 301, a yarn spreading guide roller group 302, and a fifth traction device 303), a suspension impregnation device 4 (including an impregnation tank 401 and a first traction device 402), a third yarn spreading device 5, a pre-melting device 6, a hot roller extrusion device 8, and a winding device 9 (including a fourth yarn spreading device 901 and a winding machine 902).

[0083] Application Example 1 This application example provides a method for preparing carbon fiber reinforced thermoplastic composite material using the processing system provided in Example 1. The processing method is as follows: (1) Preparation of suspension: The following ingredients were mixed in sequence: 70% water, 3% ethanol, 2% fatty alcohol polyoxyethylene ether, 20% PEEK, 2% polyethylene glycol, and 3% sodium polyacrylate. The mixture was stirred at 600 r / min for 15 h to obtain the suspension. The suspension was then placed in an impregnation tank capable of ultrasonic dispersion. (2) Unwind carbon fiber A from the yarn rack and unwind it (20 kg / cm). 2The carbon fibers are first drawn at a traction speed of 1 m / min, then pass through a threading hole, a filament comb, and a first yarn-spreading device for filament separation and spreading. They are then desized in an incinerator (at a temperature of 500℃). After desizing, the carbon fibers are spread a second time through a second yarn-spreading device. Next, the carbon fibers are impregnated in a suspension solution in an impregnation tank (at a temperature of 30℃ and an ultrasonic frequency of 30 Hz). After impregnation, they are drawn into a pre-melting furnace by a third yarn-spreading device for drying and pre-melting (at a temperature of 450℃). The dried and pre-melted carbon fibers are then drawn to an extrusion die for high-temperature pultrusion (at a temperature of 420℃ and a gap of 0.2 mm between the upper and lower dies). After high-temperature pultrusion, the carbon fibers are drawn to a hot roller group (at a temperature of 170℃ and a pressure of 0.3 MPa) for hot roller extrusion. The hot-rolled carbon fibers are then drawn to a winding machine by a fourth yarn-spreading device for winding (at a tension of 25 kg / cm²). 2 ).

[0084] Application Example 2 This application example provides a method for preparing carbon fiber reinforced thermoplastic composite material using the processing system provided in Example 1. The processing method is as follows: (1) Preparation of suspension: The following ingredients were mixed in sequence: 70% water, 5% ethanol, 5% fatty alcohol polyoxyethylene ether, 10% PEEK, 5% polyethylene glycol, and 5% sodium polyacrylate. The mixture was stirred at 600 r / min for 15 h to obtain the suspension. The suspension was then placed in an impregnation tank capable of ultrasonic dispersion. (2) Unwind carbon fiber B from the yarn rack and unwind it (15 kg / cm). 2 The carbon fibers are first drawn at a traction rate of 0.5 m / min, then pass through a threading hole, a filament comb, and a first yarn-spreading device for filament separation and spreading. They are then desized in an incinerator (at a temperature of 450℃). After desizing, the carbon fibers are spread a second time using a second yarn-spreading device. Next, the carbon fibers are impregnated in a suspension solution in an impregnation tank (at a temperature of 25℃ and an ultrasonic frequency of 20 Hz). After impregnation, they are drawn into a pre-melting furnace by a third yarn-spreading device for drying and pre-melting (at a temperature of 350℃). The dried and pre-melted carbon fibers are then drawn to an extrusion die for high-temperature pultrusion (at a temperature of 380℃ and a gap of 0.5 mm between the upper and lower dies). After high-temperature pultrusion, the carbon fibers are drawn to a hot roller group (at a temperature of 160℃ and a pressure of 0.4 MPa) for hot roller extrusion. The hot-rolled carbon fibers are then drawn to a winding machine by a fourth yarn-spreading device for winding (at a tension of 20 kg / cm²). 2 ).

[0085] Application Example 3 This application example provides a method for preparing carbon fiber reinforced thermoplastic composite material using the processing system provided in Example 1. The processing method is as follows: (1) Preparation of suspension: The following ingredients were mixed in sequence: 70% water, 0.5% ethanol, 0.5% fatty alcohol polyoxyethylene ether, 28% PEEK, 0.5% polyethylene glycol, and 0.5% sodium polyacrylate. The mixture was stirred at 600 r / min for 15 h to obtain the suspension. The suspension was then placed in an impregnation tank capable of ultrasonic dispersion. (2) Unwind carbon fiber A from the yarn rack and unwind it (30 kg / cm). 2 The carbon fibers are first drawn at a traction speed of 1.5 m / min, then pass through a threading hole, a filament comb, and a first yarn-spreading device for filament separation and spreading. They are then desized in an incinerator (at a desizing temperature of 550℃). After desizing, the carbon fibers are spread a second time using a second yarn-spreading device. Next, the carbon fibers are impregnated in a suspension solution in an impregnation tank (at a suspension impregnation temperature of 40℃ and an ultrasonic frequency of 50 Hz). After impregnation, they are drawn into a pre-melting furnace by a third yarn-spreading device for drying and pre-melting (at a pre-melting temperature of 480℃). After drying and pre-melting, the carbon fibers are drawn to an extrusion die for high-temperature pultrusion (at a high-temperature pultrusion temperature of 480℃ and a gap of 0.2 mm between the upper and lower dies). After high-temperature pultrusion, the carbon fibers are drawn to a hot roller group (at a hot roller extrusion temperature of 180℃ and a hot roller extrusion pressure of 0.5 MPa) for hot roller extrusion. After hot roller extrusion, the carbon fibers are drawn to a winding machine by a fourth yarn-spreading device for winding (winding tension of 30 kg / cm²). 2 ).

[0086] Application Example 4 This application example provides a method for preparing carbon fiber reinforced thermoplastic composite material using the processing system provided in Example 1. The processing method is as follows: (1) Preparation of suspension: The suspension is prepared by mixing water 70%, ethanol 3%, fatty alcohol polyoxyethylene ether 2%, PEEK 20%, polyethylene glycol 2% and sodium polyacrylate 3% in sequence and mixing at 600 r / min for 15 h to obtain the suspension. The suspension is then placed in an impregnation tank that can be ultrasonically dispersed. (2) Unwind carbon fiber A from the yarn rack and unwind it (20 kg / cm). 2The carbon fibers are first drawn at a traction speed of 1 m / min, then pass through a threading hole, a filament comb, and a first yarn-spreading device for filament separation and spreading. They are then desized in an incinerator (at a desizing temperature of 550℃). After desizing, the carbon fibers are spread a second time using a second yarn-spreading device. Next, the carbon fibers are impregnated in a suspension solution in an impregnation tank (at a suspension impregnation temperature of 45℃ and an ultrasonic frequency of 40 Hz). After impregnation, they are drawn into a pre-melting furnace by a third yarn-spreading device for drying and pre-melting (at a pre-melting temperature of 500℃). After drying and pre-melting, the carbon fibers are drawn to an extrusion die for high-temperature pultrusion (at a high-temperature pultrusion temperature of 450℃ and a gap of 0.2 mm between the upper and lower dies). After high-temperature pultrusion, the carbon fibers are drawn to a hot roller group (at a hot roller extrusion temperature of 175℃ and a hot roller extrusion pressure of 0.2 MPa) for hot roller extrusion. After hot roller extrusion, the carbon fibers are drawn to a winding machine by a fourth yarn-spreading device for winding (winding tension of 25 kg / cm²). 2 ).

[0087] Application Example 5 This application example provides a method for preparing carbon fiber reinforced thermoplastic composite material using the processing system provided in Example 1. The difference from Application Example 1 is that the pre-melting temperature is adjusted to 400°C.

[0088] Application Example 6 This application example provides a method for preparing carbon fiber reinforced thermoplastic composite material using the processing system provided in Example 1. The difference from Application Example 1 is that the pre-melting temperature is adjusted to 500°C.

[0089] Application Example 7 This application example provides a method for preparing carbon fiber reinforced thermoplastic composite material using the processing system provided in Example 1. The difference from Application Example 1 is that the pre-melting temperature is adjusted to 550°C.

[0090] Application Example 8 This application example provides a method for preparing carbon fiber reinforced thermoplastic composite material using the processing system provided in Example 1. The difference from Application Example 1 is that the gap between the upper and lower dies in the high-temperature pultrusion device is adjusted to 0.1 mm.

[0091] Application Example 9 This application example provides a method for preparing carbon fiber reinforced thermoplastic composite material using the processing system provided in Example 1. The difference from Application Example 1 is that the gap between the upper and lower dies in the high-temperature pultrusion device is adjusted to 0.15 mm.

[0092] Application Example 10 This application example provides a method for preparing carbon fiber reinforced thermoplastic composite material using the processing system provided in Example 1. The difference from Application Example 1 is that the gap between the upper and lower dies in the high-temperature pultrusion device is adjusted to 0.05 mm.

[0093] Application Example 11 This application example provides a method for preparing carbon fiber reinforced thermoplastic composite material using the processing system provided in Example 1. The difference from Application Example 1 is that the gap between the upper and lower dies in the high-temperature pultrusion device is adjusted to 0.25 mm.

[0094] Application Example 12 This application example provides a method for preparing carbon fiber reinforced thermoplastic composite material using the processing system provided in Example 1. The difference from Application Example 1 is that the traction rate is adjusted to 2 m / min.

[0095] Application Example 13 This application example provides a method for preparing carbon fiber reinforced thermoplastic composite material using the processing system provided in Example 1. The difference from Application Example 1 is that the traction rate is adjusted to 2.8 m / min.

[0096] Comparative Application Example 1 This comparative application example provides a method for preparing carbon fiber reinforced thermoplastic composite material using the processing system provided in Comparative Example 1. The processing method is as follows: (1) Preparation of suspension: The following ingredients were mixed in sequence: 70% water, 3% ethanol, 2% fatty alcohol polyoxyethylene ether, 20% PEEK, 2% polyethylene glycol, and 3% sodium polyacrylate. The mixture was stirred at 600 r / min for 15 h to obtain the suspension. The suspension was then placed in an impregnation tank capable of ultrasonic dispersion. (2) Unwind the carbon fiber from the yarn rack and unwind it (20 kg / cm). 2The carbon fibers are first drawn at a traction speed of 1 m / min, then pass through a threading hole, a filament comb, and a first yarn-spreading device for filament separation and spreading. They are then desized in an incinerator (at a temperature of 500℃). After desizing, the carbon fibers are spread a second time by a second yarn-spreading device. Next, the carbon fibers are impregnated in a suspension solution in an impregnation tank (at a temperature of 30℃ and an ultrasonic frequency of 30 Hz). After impregnation, they are drawn into a pre-melting furnace by a third yarn-spreading device for drying and pre-melting (at a temperature of 450℃). The dried and pre-melted carbon fibers are then drawn to a hot-press roller group (at a temperature of 170℃ and a pressure of 0.3 MPa) for hot-pressing. The hot-pressed carbon fibers are then drawn to a winding machine by a fourth yarn-spreading device for winding (at a tension of 25 kg / cm²). 2 ).

[0097] This invention uses a metallographic microscope (BX53MRF-S) to characterize the carbon fiber reinforced thermoplastic composite material provided in Example 1 and Comparative Application Example 1. The metallographic images are as follows. Figure 4-5 As shown, the scale bar is 10 μm. From Figure 4 It can be seen that the carbon fiber reinforced thermoplastic composite material provided in Example 1 of this invention has excellent surface quality and no obvious defects. From Figure 5 It can be seen that the carbon fiber reinforced thermoplastic composite material provided in Comparative Application Example 1 of the present invention has too many pore defects and exhibits local agglomeration.

[0098] Test methods The carbon fiber reinforced thermoplastic composites prepared using the corresponding use cases and comparative application examples were subjected to the following performance tests: (1) Width (mm): Measured using vernier calipers; (2) Thickness (mm): Tested in accordance with GB / T 28461-2012; (3) Appearance of carbon fiber reinforced thermoplastic composite material: Observe whether the material surface is smooth and whether there are fuzz, cracks, or white spots (unmelted resin powder). Smoothness without fuzz, cracks, or white spots is good, fuzz with a small number of white spots and cracks is good, and severe cracks are poor. (4) Tensile strength (MPa): Tested according to ASTM D3039; (5) Interlaminar shear strength (MPa): Tested according to ASTM D2344; (6) Bending strength (MPa): Tested according to ASTM D7264; (7) Compressive strength (MPa): Tested according to ASTM D3410.

[0099] The test results are shown in Table 1 below: Table 1 The test results show that: (1) By applying Examples 1-13 and Comparative Example 1, Figure 4-5 As can be seen, this invention uses a powder suspension method to prepare carbon fiber reinforced thermoplastic composites. By optimizing the process steps and parameters of the powder suspension method, the shortcomings of traditional methods such as melt impregnation in preparing prepregs are avoided, effectively ensuring the surface quality and mechanical properties of the prepared carbon fiber reinforced thermoplastic composites. This can meet the needs of aerospace and other fields for carbon fiber reinforced thermoplastic composites. The resulting carbon fiber reinforced thermoplastic composites have a width of 66.72-74.89 mm, a thickness of 0.14-0.20 mm, tensile properties of 1848-2725 MPa, interlaminar shear strength of 88-115 MPa, flexural strength of 1137-1752 MPa, and compressive strength of 804-1070 MPa.

[0100] (2) As can be seen from Examples 1 and 5-13, by further limiting the parameters such as the pre-melting temperature, the gap between the upper and lower dies in the high-temperature extrusion, and the traction rate in the processing, the present invention can achieve better technical effects in ensuring the surface quality and mechanical properties of carbon fiber reinforced thermoplastic composites.

[0101] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for preparing a carbon fiber reinforced thermoplastic composite material, characterized in that, The preparation method includes sequentially impregnating carbon fibers with a suspension, pre-melting, and high-temperature pultrusion.

2. The method for preparing carbon fiber reinforced thermoplastic composite material according to claim 1, characterized in that, The number of carbon fiber bundles is 12-24 k.

3. The method for preparing carbon fiber reinforced thermoplastic composite material according to claim 1 or 2, characterized in that, The temperature for impregnation with the suspension is 25-45℃; Preferably, the suspension impregnation is performed under ultrasonic conditions; Preferably, the frequency of the ultrasound is 10-50 Hz; Preferably, the pre-melting temperature is 300-500℃; Preferably, the temperature of the high-temperature pultrusion is 350-500℃.

4. The method for preparing the carbon fiber reinforced thermoplastic composite material according to any one of claims 1-3, characterized in that, The suspension impregnated by the suspension comprises, by mass percentage: 5-30% thermoplastic resin powder, 0.5-5% dispersant, 0.5-5% suspending agent, 0.5-5% thickener, 0.5-5% surfactant, and the balance being solvent; Preferably, the thermoplastic resin powder includes PEEK; Preferably, the D50 particle size of the PEEK is 10-50 µm; Preferably, the melting temperature of the PEEK is 300-350°C; Preferably, the dispersant comprises ethanol; Preferably, the suspending agent comprises polyethylene glycol; Preferably, the thickener comprises any one or a combination of at least two of polyvinyl alcohol, sodium polyacrylate, or polyacrylamide; Preferably, the surfactant includes nonylphenol surfactants and / or fatty alcohol polyoxyethylene ether surfactants; Preferably, the solvent includes water.

5. The method for preparing the carbon fiber reinforced thermoplastic composite material according to any one of claims 1-4, characterized in that, The method for preparing the carbon fiber reinforced thermoplastic composite material further includes unwinding, splitting, first yarn spreading, desizing and second yarn spreading in sequence before suspension impregnation, third yarn spreading between suspension impregnation and pre-melting, and hot roller extrusion, fourth yarn spreading and winding in sequence after high-temperature pultrusion.

6. The method for preparing carbon fiber reinforced thermoplastic composite material according to claim 5, characterized in that, The unwinding tension is 10-30 kg / cm. 2 ; Preferably, the winding tension is 20-30 kg / cm. 2 ; Preferably, the desizing temperature is 400-550℃; Preferably, the temperature of the hot roller extrusion is 160-180°C; Preferably, the pressure of the hot roller extrusion is 0.1-0.5 MPa; Preferably, the carbon fiber is subjected to unwinding, filament splitting, first yarn spreading, desizing, second yarn spreading, suspension impregnation, third yarn spreading, pre-melting, high-temperature pultrusion, hot roller extrusion, fourth yarn spreading and winding in sequence. Preferably, the traction rate is 0.3-2 m / min.

7. A carbon fiber reinforced thermoplastic composite material processing system for implementing the preparation method of the carbon fiber reinforced thermoplastic composite material as described in any one of claims 1-6, characterized in that, The carbon fiber reinforced thermoplastic composite material processing system includes: a suspension impregnation device, a pre-melting device, and a high-temperature pultrusion device.

8. The carbon fiber reinforced thermoplastic composite material processing system according to claim 7, characterized in that, The suspension impregnation device includes an impregnation tank and a first traction device located at the bottom of the impregnation tank; Preferably, the first traction device is submerged in the suspension; Preferably, the pre-melting device includes a pre-melting furnace; Preferably, the high-temperature pultrusion apparatus includes a second traction device, an extrusion die, and a third traction device; Preferably, the extrusion die has an upper die and a lower die arranged in parallel. Preferably, the gap between the upper mold and the lower mold is 0.1-0.5 mm.

9. The carbon fiber reinforced thermoplastic composite material processing system according to claim 7 or 8, characterized in that, The carbon fiber reinforced thermoplastic composite material processing system also includes an unwinding and unwinding device and a desizing device arranged sequentially before the suspension impregnation system, and a hot roller extrusion device and a winding device arranged sequentially after the high temperature pultrusion device. Preferably, the unwinding and spreading device includes a yarn frame, a filament comb, and a first spreading device arranged in sequence; Preferably, the deslurry removal device includes an incinerator; Preferably, a second yarn spreading device is provided between the desizing device and the suspension impregnation device; Preferably, a third yarn spreading device is provided between the suspension impregnation device and the pre-melting device; Preferably, the third yarn spreading device includes a guide roller group; Preferably, the hot roller extrusion device includes a hot roller assembly; Preferably, the winding device includes a fourth yarn spreading device and a winding machine.

10. A carbon fiber reinforced thermoplastic composite material prepared by the method for preparing carbon fiber reinforced thermoplastic composite material according to any one of claims 1-6.

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