High-performance thermoplastic prepreg production system, production method and application

Abstract

The invention relates to a high-performance thermoplastic prepreg production system and a high-performance thermoplastic prepreg production method. The production system comprises a creel, a yarn spreading device, a tension adjusting roller, a dipping glue tank, a high-temperature furnace, a high-temperature compression roller, a melt extruder, a film extrusion die head, a melt dipping die, a cooling shaping system, a rim charge cutting system and a winding device which are arranged in the fiber movement direction. During production, firstly, continuous fibers are mounted on a creel, and the fibers sequentially pass through a yarn spreading device, a tension adjusting roller, a dipping glue tank, a high-temperature furnace, a high-temperature compression roller, a film extrusion die head, a melting dipping die, a cooling shaping system, a rim charge cutting system and a winding system to obtain the high-performance thermoplastic prepreg. According to the invention, a step-by-step impregnation process of a suspension method and a melt impregnation method is adopted, resin powder is firstly melted among fibers and then is subjected to melt extrusion, and melt impregnation is carried out through a wave-shaped mold, so that the production cost of the prepreg is reduced, and the production quality and stability of the prepreg are ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of composite materials and material processing, and in particular to a high-performance thermoplastic prepreg production system, production method and application. Background Art

[0002] Thermoplastic composite welding material is a prepreg with high wettability and a resin-rich layer. Prepreg is an intermediate material formed by pre-combining a resin matrix and reinforcing fibers through a specific process. Its core advantage is that it can improve product performance by precisely controlling the resin content and fiber distribution. Depending on the type of resin matrix, prepregs can be divided into two categories: thermosetting and thermoplastic. Among them, thermoplastic prepregs have gradually become a hot topic of industry research due to their advantages such as recyclability, impact resistance and high molding efficiency. Thermoplastic carbon fiber reinforced composite material is a high-performance composite material with a thermoplastic resin (such as PEEK, PEKK, PPS, etc.) as the matrix and carbon fiber as the reinforcing phase. It combines the recyclability and impact resistance of thermoplastic resin with the high strength and lightweight properties of carbon fiber, making it an ideal material for aerospace, automotive, new energy and other fields.

[0003] At present, the manufacturing methods of unidirectional tape prepregs include powder impregnation, melt impregnation, and suspension methods. The powder impregnation method mainly uses electrostatic or fluidized bed adsorption of resin powder. This method requires a closed environment and has high requirements for production equipment. In addition, the powder impregnation method will also lead to a strong dust environment, there is a risk of dust explosion, and there are major safety hazards in the production process. The melt impregnation method is to heat the thermoplastic resin to a molten state to make it a melt with a certain fluidity. Under the extrusion action of the high-temperature impregnation mold, the melt and the fiber are fully contacted and impregnated with the fiber, finally forming a thermoplastic prepreg.

[0004] Compared to melt and powder methods, the suspension method is a safe, efficient, and stable production method. This method utilizes a suspension to evenly impregnate resin powder into fibers. Heating removes the liquid component, allowing the powder particles to melt and penetrate the fibers. This method is suitable for producing prepregs with high-melting-point, high-viscosity resins (such as PEEK, PEKK, and PPS). Furthermore, the suspension method significantly outperforms melt and powder impregnation methods in reducing fiber damage, improving material performance, and lowering energy consumption and environmental costs. It is expected to become the mainstream production technology for thermoplastic unidirectional tape prepregs.

[0005] A search revealed that several patents have disclosed the use of a suspension method to prepare thermoplastic prepregs. For example, Chinese patent CN117621300A relates to a method for preparing a high-performance thermoplastic polyaryletherketone wide-width fabric prepreg. This solution adopts a powder suspension hot melt method to prepare fabric prepregs through multiple cycles of impregnation and drying processes, and can prepare fabric prepregs with a high resin content of 30% to 50%. However, in this solution, the prepreg is dried and melted in a vertical oven and then infiltrated in a suspension. The rapid cooling of the resin in a high-temperature state by the suspension may cause problems such as uneven crystallization and voids inside the fibers. In addition, the resin deposition process in this solution relies on multiple heating and cooling cycles, which can easily cause uneven heating, resulting in weld marks inside the resin, and a decrease in the mechanical properties of the product.

[0006] Chinese patent CN117774370A discloses a method for preparing thermoplastic composite materials suitable for automatic placement in-situ consolidation process. This solution uses suspensions with different resin concentrations to size and impregnate the fibers respectively. Since the sizing agent is a relatively low-viscosity resin of the same type, it is not only beneficial for the resin to impregnate the fibers, but also beneficial for reducing the viscosity of the resin system, and is more conducive to removing the air wrapped in the placement process and reducing the porosity of the composite material. However, in this solution, both suspensions rely on resin powder with extremely low particle size. Although it is beneficial for the good infiltration of the resin into the fibers, it greatly increases the manufacturing cost of the prepreg. In addition, this method cannot achieve the preparation of a resin-rich layer and cannot achieve the manufacture of welding materials. Summary of the Invention

[0007] The present invention mainly addresses the above-mentioned problems existing in the existing thermoplastic prepreg preparation method and provides a high-performance thermoplastic prepreg production system, comprising a pay-off device, an impregnation tank (14), a heating and melting device, a laminating device, and a melt impregnation mold (21) arranged in sequence along the fiber movement direction. The pay-off device is used to provide continuous fibers and then produce thermoplastic prepreg; the impregnation tank (14) contains a thermoplastic resin suspension, and when the fibers pass through, the thermoplastic resin particles will adhere to the fibers; the heating and melting device is mainly used to heat the fibers so that the thermoplastic resin particles attached to the surface of the fibers melt and impregnate the fibers; the laminating device is mainly used to additionally adhere the molten thermoplastic resin to the fibers; and the melt impregnation mold (21) is mainly used for hot pressing the prepreg.

[0008] In the above scheme, the pay-off device includes a yarn rack (1) and a yarn spreading device (2), at least one fiber roll is arranged on the yarn rack (1), and the fibers in the fiber roll pass through the yarn spreading device (2) to continuously feed the entire production system.

[0009] In the above solution, a guide roller and a tension adjustment roller (4) are further provided between the yarn spreading device (2) and the dipping glue tank (14).

[0010] In the above scheme, an impregnation guide roller and an ultrasonic device (9) are provided at the bottom of the impregnation tank (14), and the fibers pass between the impregnation guide roller and the ultrasonic device (9).

[0011] In the above scheme, the production system also includes an impregnation feeding assembly matched with the impregnation glue tank (14), and the impregnation feeding assembly includes a feeding barrel (5), a concentration regulating barrel (15), and a raw material supply system (16). The feeding barrel (5) is respectively connected to the impregnation glue tank (14) and the concentration regulating barrel (15), and the concentration regulating barrel (15) is respectively connected to the impregnation glue tank (14) and the raw material supply system (16).

[0012] In the above scheme, the heating and melting device is specifically a high-temperature furnace (13), and the heating method of the high-temperature furnace (13) is electric infrared heating, the heating temperature is 400~450℃, and the effective heating length is 1.5~2.5m.

[0013] In the above scheme, the production system also includes a high-temperature pressing roller (17), which is arranged between the high-temperature furnace (13) and the laminating device. The fiber strip coming out of the high-temperature furnace (13) passes through the high-temperature pressing roller (17) and arrives at the laminating device for laminating treatment.

[0014] Furthermore, the high-temperature pressure roller (17) includes at least one pair of electrically heated rollers, and the spacing between the rollers is adjustable, and the heating temperature thereof is 150-200°C.

[0015] In the above scheme, the laminating device includes a film extrusion die (19) and a melt extruder (20). The thermoplastic resin particles enter the melt extruder (20) and are melted and extruded, and then attached to the fiber belt through the film extrusion die (19) to complete the laminating process.

[0016] In the above solution, the melt impregnation mold (21) includes a matching mold A and a mold B, and the relative molding surfaces of the two are continuous wavy curved surfaces.

[0017] Furthermore, the heating temperature of the melt impregnation mold (21) is 350°C to 400°C, and a chamfering treatment is performed at its fiber inlet.

[0018] In the above scheme, the production system also includes a cooling and shaping system (22), a side material cutting system (23), a side material recovery system (24), and a winding device (26) which are arranged in sequence along the fiber movement direction and located downstream of the melt impregnation mold (21).

[0019] The present invention also provides a method for producing high-performance thermoplastic prepreg, comprising: fibers on a yarn rack (1) pass through a yarn spreading device (2) and a tension adjustment roller (4) in sequence and then enter an impregnation tank (4); after the fibers absorb resin particles in a thermoplastic resin suspension in the impregnation tank (4), they pass through a high-temperature furnace (13), a high-temperature pressing roller (17), an extrusion die (19), a melt impregnation mold (21), a cooling and shaping system (22), an edge material cutting system (23), and finally the thermoplastic prepreg is wound by a winding device (26).

[0020] In the above scheme, the composition of the thermoplastic resin suspension includes 1wt%~50wt% of high-performance thermoplastic resin powder, 50wt%~99wt% of deionized water, 0.01wt%~5wt% of surfactant, and 1wt%~5wt% of dispersant, totaling 100%.

[0021] The thermoplastic resin powder is selected from at least one of PI, PEI, PEEK, PEAK, PEKK, LMPAEK, and PPS. The surfactant is selected from at least one of sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, polyoxyethylene stearates, polyoxyethylene octanol ethers, cetyltrimethylammonium bromide, sodium docusate, ceteareth-25, dimethylformamide, and polyethylene glycol octylphenyl ether. The dispersant is selected from at least one of ethanol, acetone, nonionic water-soluble cellulose, nonionic water-soluble hydroxypropyl methylcellulose, polyvinyl pyrrolidone, polyvinyl alcohol, polyethylene glycol, polyethylene glycol monostearate, hydroxymethylcellulose polyethylene glycol, polyvinyl pyrrolidone, and hydroxyethyl cellulose.

[0022] In the above scheme, the molten thermoplastic resin attached to the fiber tape from the film extrusion die (19) is the same as or different from the thermoplastic resin selected for preparing the thermoplastic resin suspension, and is preferably the same.

[0023] Compared with existing similar products or technologies, the improvements of this invention are mainly reflected in the following aspects: (1) The present invention adopts a suspension method and a melt impregnation method in a step-by-step impregnation process, so that the resin powder with a smaller particle size is first melted between the fibers, and then the resin particles are melt-extruded as raw materials and melt-impregnated through a wavy mold, thereby reducing the demand for resin powder material. While reducing the production cost of the prepreg, it also ensures the production quality and stability of the prepreg.

[0024] (2) The present invention adopts an infrared induction device for heating, and utilizes infrared light to irradiate carbon fiber. The heat generated by induction is transferred from the carbon fiber single filament to the resin between the single filaments. Through the excellent thermal conductivity of carbon fiber, the uniformity of the prepreg heating process is improved and the formation of pore defects between fibers is reduced.

[0025] (3) The present invention adopts a step-by-step impregnation process. By increasing the flow rate of the melt in the second step of impregnation, the thickness of the resin layer on the surface of the prepreg is increased. The unidirectional tape prepregs with a high resin content on the surface are more easily bonded to each other after heating, which effectively improves the bonding effect between the unidirectional tape prepregs during the automatic placement process.

[0026] (4) The present invention reduces the change in resin concentration of the suspension through a circulating feeding system, thereby improving the production quality and stability of thermoplastic composite welding materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the high-performance thermoplastic prepreg production system of the present invention.

[0028] Figure 2 Schematic diagram of different impregnation states of fiber tape.

[0029] Figure 3 Schematic diagram comparing the melting effects of oven heating and high-temperature furnace infrared induction heating.

[0030] Figure 4 This is a schematic cross-sectional view of the prepreg product prepared according to the present invention.

[0031] Figure 5 Schematic diagram for the comparison of thin and thick welding layers.

[0032] Figure 6 The present invention is a flow chart of the production method of the high-performance thermoplastic prepreg.

[0033] Figure 1: creel, 2: yarn unrolling device, 3: guide roller No. 1, 4: tension adjustment roller, 5: feeding barrel, 6: guide roller No. 2, 7: feeding port, 8: impregnation guide roller No. 1, 9: ultrasonic device, 10: impregnation guide roller No. 2, 11: discharge port, 12: guide roller No. 3, 13: high temperature furnace, 14: impregnation glue tank, 15: concentration adjustment barrel, 16: raw material supply system, 17: high temperature pressure roller, 18: guide roller No. 4 Roller, 19-film extrusion die, 20-melt extruder, 21-melt impregnation mold, 22-cooling and shaping system, 23-edge material cutting system, 24-edge material recovery system, 25-No. 5 guide roller, 26-winding device; 101-resin powder particles, 102-carbon fiber monofilament, 103-resin particle melt, 104-resin-rich layer, 105-resin layer between fibers; 210-thin welding layer, 220-thick welding layer. DETAILED DESCRIPTION

[0034] To enable those skilled in the art to fully understand the technical solutions and beneficial effects of the present invention, the following is a further detailed description with reference to specific embodiments and accompanying drawings. It should be emphasized that the following embodiments are merely preferred embodiments of the present invention and do not constitute any limitation of the present invention. Any simple modifications or substitutions based on these embodiments will fall within the scope of protection of the present invention.

[0035] like Figure 1 The high-performance thermoplastic prepreg production system shown mainly includes a creel 1, a yarn unwinding device 2, a tension adjustment roller 3, an impregnation tank 14, a high-temperature furnace 13, a high-temperature pressing roller 17, a melt extruder 20, a film extrusion die 19, a melt impregnation mold 21, a cooling and shaping system 22, a side material cutting system 23, a winding device 26, and several guide rollers (such as 4, 6, 8, 10, 12, 18, 25, etc.). The structures and functions of these components are as follows: The creel 1 consists of a bobbin roll and a frame. The rolls are mounted on both sides of the frame and can rotate. Thirty sets of rolls are mounted on each side, and each roll can hold a set of bobbins. Therefore, the creel 1 can simultaneously hold up to 60 sets of yarn rolls. The yarn rolls are wound with T300 carbon fiber yarn. The rolls are equipped with damping devices, and the creel 1 is also equipped with yarn guide holes corresponding to each roll. As the rolls rotate, the yarn rolls pass through the guide holes and into the impregnation tank 14, ensuring continuous feeding of carbon fiber.

[0036] The yarn spreading device 2 is located downstream of the creel 1. It is a comb-type yarn spreading structure that can be folded and changed in angle. By changing the angle between the yarn spreading device and the direction of fiber travel and applying low-amplitude vibration, the fiber yarn can be spread.

[0037] The tension-adjusting roller 4 is located downstream of the unwinding device 2 and can be moved up and down to adjust its height, thereby adjusting the fiber tension. The roller can be moved up and down a distance of 100 mm to 500 mm (preferably 200 mm to 400 mm), corresponding to an adjustable tension range of 0.1 N to 50 N. To prevent damage from friction caused by the pressure applied by the roller, the roller is coated with a low-friction material such as polytetrafluoroethylene (PTFE), ceramic, brass, or mild steel, preferably polytetrafluoroethylene. As a supplement, guide rollers 1 (number 3) and 6 (number 6) are positioned at different heights upstream and downstream of the roller 4 to better guide the fiber's directional movement.

[0038] The impregnation tank 14 is located downstream of the tension adjustment roller 4. An ultrasonic device 9 and the number one impregnation guide roller 8 and the number two impregnation guide roller 10 are installed at the bottom of the impregnation tank 14. A rubber pad is installed on the contact surface between the ultrasonic device and the impregnation tank to prevent direct contact between the two and cause metal fatigue in the impregnation tank. A discharge port 11 is provided at the bottom of the impregnation tank, which is controlled by an electric switch. The impregnation discharged from the discharge port 11 enters the concentration adjustment barrel 15, which is connected to the raw material supply system 16. A concentration detection device is provided in the impregnation tank 14, and the concentration detection device is connected to the electric switch of the discharge port. When the concentration detection device detects that the concentration of the suspension in the impregnation tank has dropped to a critical value, it transmits a signal to the electric switch to control the discharge port 11 to open, and the suspension in the impregnation tank 14 is transferred to the concentration adjustment barrel 15. The raw material supply system 16 then adds the corresponding raw materials to the concentration adjustment barrel to adjust the concentration of the suspension to the required concentration. Because the concentration adjustment tank 15 is connected to the feeding tank 5, the suspension with adjusted concentration is transported to the feeding tank 5 and then flows back into the dipping tank 14 through the feeding port 7 and the metering water pump. The power of the metering water pump is controlled by the signal from the concentration detection device, and the corresponding amount of suspension is added to the dipping tank 14 according to the size and strength of the signal.

[0039] A high-temperature furnace 13 is located downstream of the impregnation tank 14. The impregnated fibers are guided by the third guide roller 12 into the high-temperature furnace 13 for heating. The high-temperature furnace 13 uses electric infrared heating with an infrared light wavelength range of 0.78 to 15 μm, preferably 1 to 2.5 μm. The operating temperature is 400 to 450°C, and the effective heating length is 1.5 to 2.5 m.

[0040] Downstream of the high-temperature furnace 13 is a high-temperature pressure roller 17. This roller consists of a pair of electrically heated rollers, with a heating range of 150-200°C. The rollers' spacing is adjustable, and the pressure applied to the fiber is controlled by adjusting the gap between the upper and lower rollers. The pressure is detected by a pressure sensor. To ensure smooth fiber ribbon operation, a fourth guide roller 18 is located downstream of the high-temperature pressure roller 17.

[0041] The melt extruder 20 is located downstream of the high-temperature furnace 13. The melt extruder 20 can be a single-screw extruder or a twin-screw extruder. The resin pellets are melt-processed during the screw rotation process, and the output of the melt can be adjusted by controlling the screw speed.

[0042] The melt extruder 20 is connected to the film extrusion die 19, which is facing the fiber belt feeding direction. The melt extruded by the melt extruder 20 is attached to the fiber belt through the film extrusion die 19, thereby achieving the coating of the fiber belt.

[0043] The fiber strip after coating is transported to the melt impregnation mold 21. The melt impregnation mold 21 is divided into an upper and lower mold, and the inner surfaces of the upper and lower molds are continuous wavy surfaces, thereby forming a wavy flow channel. The width of the wavy flow channel is 300mm~1000mm, preferably 500mm~800mm, and the length of the wavy flow channel is 500mm~1500mm, preferably 1000mm~1200mm. The curved surface transition of the wavy flow channel is smooth, and the minimum radius of curvature should not be less than 500mm. The height difference between the lowest and highest points of the curved surface is controlled to be 50mm~100mm, preferably 70mm~90mm. A chamfer with a radius of 1mm~10mm, preferably 3mm~5mm, is made at the entrance (left side) of the melt impregnation mold 21. The melt impregnation mold 21 is equipped with an electric heating device, and the heating temperature is 350℃~400℃.

[0044] A cooling and shaping system 22 is provided downstream of the melt impregnation mold 21. The cooling and shaping system 22 comprises two pairs (not necessarily one, but more than one) of rollers arranged side by side. Copper or stainless steel tubes are provided inside the rollers, through which cold water or cooling oil circulates to dissipate heat and cool the rollers.

[0045] Downstream of the cooling and setting system 22 is a scrap removal system 23. Cutting is performed by two side cutters, spaced 100mm to 1500mm apart to accommodate scraps of varying widths. A scrap recovery system 24 is also installed below and to the side of the scrap removal system 23 to recover scrap material.

[0046] A fifth guide roller 25 and a winding device 26 are sequentially arranged downstream of the edge material cutting system 23. The winding device 26 has a winding speed of 1 to 5 m / min, preferably 1 to 2 m / min.

[0047] Method for producing high performance thermoplastic prepreg using this system Figure 6 The specific process is as follows: (1) Installing continuous fiber. The fiber is pulled out from the creel 1 and passes through the yarn unwinding device 2, the tension adjustment roller 4, the impregnation tank 14, the high-temperature furnace 13, the high-temperature pressing roller 17, the film extrusion die 19, the melt impregnation mold 21, the cooling and shaping system 22, the edge material cutting system 23 and the winding system 26.

[0048] (2) Adjust the yarn spreading device 2 so that there is no obvious gap between the yarns, and use the tension adjustment roller 4 to adjust the tension of each yarn so that the yarn remains stable after spreading.

[0049] (3) As the fiber moves forward, it passes through the impregnation tank 14, where it absorbs the resin powder particles in the suspension. It then enters the high-temperature furnace 13 for heating, removing low-boiling point components while the resin melts and impregnates the fiber. After the fiber is initially compacted by the high-temperature pressure roller 17, it is coated by the extrusion die 19. The fiber strip carrying the molten resin enters the melt impregnation mold 21, where the fiber is fully impregnated. Finally, it is cooled and solidified by the cooling and setting system 22.

[0050] (4) Adjust the spacing of the cutters of the edge material removal system 23 to remove the defective edge materials on both sides of the fiber belt. The main material is guided by the No. 5 guide roller 25 and then reeled by the reeling device 26.

[0051] During the entire process, the suspension in the impregnation tank 14 is a water-based high-performance thermoplastic resin powder suspension, which comprises: 1wt%~50wt% of high-performance thermoplastic resin powder, 50wt%~99wt% of deionized water, 0.01wt%~5wt% of surfactant, and 1wt%~5wt% of dispersant, totaling 100%.

[0052] The thermoplastic resin powder is specifically one or more of special engineering plastics or engineering plastics such as polyimide (PI), polyetherimide (PEI), polyetheretherketone (PEEK), polyaryletherketone (PAEK), polyetherketoneketone (PEKK), low melting point polyaryletherketone (LMPAEK), polyphenylene sulfide (PPS), etc. The density of the resin powder is greater than 1g / cm 3 , average particle size D 50 Less than 20 μm, preferably 5 μm to 10 μm.

[0053] The surfactant is selected from one or more of sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, polyoxyethylene stearates, polyoxyethylene octanol ethers, cetyltrimethylammonium bromide, sodium docusate, ceteareth-25, dimethylformamide, and polyethylene glycol octylphenyl ether, preferably sodium dodecyl sulfate.

[0054] The dispersant is selected from one or more of ethanol, acetone, nonionic water-soluble cellulose, nonionic water-soluble hydroxypropyl methylcellulose, polyvinyl pyrrolidone, polyvinyl alcohol, polyethylene glycol, polyethylene glycol monostearate, hydroxymethyl cellulose polyethylene glycol, polyvinyl pyrrolidone, and hydroxyethyl cellulose, preferably ethanol, acetone, polyvinyl alcohol or polyethylene glycol.

[0055] Example 1 The product prepared in this embodiment is a CF / PEKK prepreg tape, and its production process includes the following two stages.

[0056] Phase 1: Production preparation First, 18 rolls of 3K tow carbon fiber (T300 model) are installed on creel 1. The fiber is pulled from the creel and passes through the unwinding device 2, the first guide roller 3, the tensioning roller 4, the second guide roller 6, the impregnation tank 14, the third guide roller 12, the high-temperature furnace 13, the high-temperature pressing roller 17, the fourth guide roller 18, the film extrusion die 19, the melt impregnation mold 21, the cooling and setting system 22, the edge trimming system 23, the fifth guide roller 25, and the winding system 26. After the fiber is unwound, the tensioning roller 4 is opened and a tension of 30-45N is applied to the fiber to straighten it. Simultaneously, the unwinding device 2 is activated and its opening and closing angles are adjusted to eliminate noticeable gaps between the yarns. The evenly unwound yarn has a width of 140mm.

[0057] Subsequently, the high-temperature furnace 13, high-temperature pressure roller 17, and melt impregnation mold 21 were preheated to 400°C, 180°C, and 360°C, respectively. Simultaneously, water flow began to the cooling and setting system 22 in preparation for cooling. The prepared suspension was added to the impregnation tank (20 L) and the feed tank (20 L). The ultrasonic device 9 in the impregnation tank 14 and the mechanical stirring device in the feed tank 5 were activated to maintain a stable suspension system.

[0058] The suspension was prepared by uniformly mixing 10 parts of ethanol, 10 parts of acetone, 0.5 parts of polyvinyl alcohol with a molecular weight of 600, 1 part of polyethylene glycol with a molecular weight of 600, and 0.5 parts of sodium lauryl sulfate. The mixture was then added with 1 part of PEKK resin powder and stirred thoroughly until the powder was completely wetted. The mixture was then added to 77 parts of water and stirred thoroughly until uniformly dispersed to obtain approximately 40 L of a water-based suspension.

[0059] Prepare the melt extruder. Set the temperature of the melt extruder 20 to 370°C and gradually add PEKK pellets from the feed port of the melt extruder 20. When the melt output stabilizes, stop the screw and install the film extrusion die 19 at the extruder outlet before starting the next stage.

[0060] Phase 2: Production Turn on the winding device 26, setting the fiber's travel speed to 1.5 m / min. As the fiber passes through the impregnation tank 14, it absorbs the PEKK resin powder particles in the suspension. Heat in the high-temperature furnace 13 volatilizes and removes low-boiling-point components, further molten resin impregnates the internal fibers, and then is initially compacted by the high-temperature pressure roller 17 at a pressure of 1-2 MPa. During this period, the screw speed of the melt extruder 20 is adjusted to maintain a glue output of 35 ± 1 g / min. The fiber strip is then coated by the film extrusion die 19.

[0061] The fiber tape, carrying the molten resin, enters the melt impregnation mold 21, where the mold's wavy surface squeezes the fibers, achieving secondary impregnation of the tape. The tape is then cooled and solidified by the cooling and setting system 22 at a cooling rate of 50°C / min. Finally, the edge trimming system 23 removes defects from both sides of the tape. The main material is guided by the fifth guide roller 25 and then reeled up by the winding device 26, resulting in a 130mm wide thermoplastic prepreg product (i.e., CF / PEKK prepreg tape).

[0062] In order to fully understand the impregnation state of the fiber tape at different stages during the preparation process, samples were taken for analysis and testing. It was found that the impregnation state of the fiber tape at different stages was different. Figure 2 shown. Figure 2 (a) shows the state of the fiber tape after the first dipping in the dipping tank. After the suspension has soaked the fiber tape, the resin powder particles 101 are evenly distributed between the carbon fiber filaments 102. Figure 2 (b) shows the state of the fiber tape during the second impregnation in the melt impregnation mold, where the resin pellet melt 103 fully wraps the fiber tape through the extrusion of the mold; Figure 2 (c) shows the state of the fiber tape after passing through the cooling and shaping system. The resin is successfully enriched in the outer layer of the fiber tape to form a resin-rich layer 104, which together with the inter-fiber resin layer 105 constitutes the entire prepreg.

[0063] In addition, in order to understand the melting effect of thermoplastic resin under different heating methods, the high-temperature furnace infrared induction heating method in Example 1 was replaced with oven heating of the same power, and samples were taken after production for analysis. The experimental results show that there are obvious differences in the melting effect of thermoplastic resin under the two different heating methods. Figure 3 shown. Figure 3 (E) Under oven heating conditions, heat is transferred from the outside of the fiber belt to the inside of the fiber belt. The resin powder particles near the outside will reach the melting point and melt first, resulting in the internal voids being unable to be discharged, forming pore defects d inside the fiber belt. Figure 3 (e) Under infrared induction heating in a high-temperature furnace, carbon fibers absorb infrared light at a higher rate than resin and possess excellent thermal conductivity. When irradiated with infrared light, they fully absorb the energy and rapidly heat up, evenly conducting the heat. This process melts the resin immediately where it comes into contact with the fibers. This heating method, where heat diffuses from the inside out, effectively removes voids within the fiber ribbon, thereby reducing internal porosity defects.

[0064] Finally, in order to understand the welding effect of the obtained prepreg, the laminating and melt impregnation steps in Example 1 were omitted, and a comparative material was additionally prepared, that is, a prepreg without the resin-rich layer 104. The two prepregs were welded to themselves, as shown in FIG. Figure 5(F) and (f). Since the prepreg surface layer in the comparative example does not have the resin-rich layer 104, the welding layer 210 obtained after welding is relatively thin ( Figure 5 F), poor interlayer resin compatibility and low strength. In contrast, the prepreg produced in Example 1 has a resin-rich surface layer 104. The resulting weld layer 220 is thicker after welding, exhibiting better interlayer resin compatibility and high strength. This experimental comparison fully demonstrates the improved weldability of the prepreg tape by the resin-rich layer 104.

[0065] Example 2 The product prepared in this embodiment is a CF / LMPAEK prepreg tape, and its production process includes the following two stages.

[0066] Phase 1: Production preparation First, 18 rolls of 3K tow carbon fiber (T300 model) are installed on creel 1. The fiber is pulled from the creel and passes through the unwinding device 2, the first guide roller 3, the tensioning roller 4, the second guide roller 6, the impregnation tank 14, the third guide roller 12, the high-temperature furnace 13, the high-temperature pressing roller 17, the fourth guide roller 18, the film extrusion die 19, the melt impregnation mold 21, the cooling and setting system 22, the edge trimming system 23, the fifth guide roller 25, and the winding device 26. After the fiber is unwound, the tensioning roller 4 is opened and a tension of 30 to 45 N is applied to the fiber to straighten it. Simultaneously, the unwinding device 2 is activated and its opening and closing angles are adjusted to eliminate noticeable gaps between the yarns. The evenly unwound yarn has a width of 144 mm.

[0067] Subsequently, the high-temperature furnace 13, high-temperature pressure roller 17, and melt impregnation mold 21 were preheated to 360°C, 140°C, and 320°C, respectively. Simultaneously, water flow began to the cooling and setting system 22 in preparation for cooling. The prepared suspension was added to the impregnation tank (20 L) and the feed tank (20 L). The ultrasonic device 9 in the impregnation tank 14 and the mechanical stirring device in the feed tank 5 were activated to maintain a stable suspension system.

[0068] The suspension was prepared by uniformly mixing 10 parts of ethanol, 10 parts of acetone, 0.5 parts of polyvinyl alcohol (molecular weight: 600), 1 part of polyethylene glycol (molecular weight: 600), and 0.5 parts of sodium lauryl sulfate. The mixture was then added with 1 part of LMPAEK resin powder and stirred thoroughly until the powder was completely wetted. The mixture was then added to 77 parts of water and stirred thoroughly until uniformly dispersed to obtain approximately 40 L of a water-based suspension.

[0069] Prepare the melt extruder. Set the temperature of the melt extruder 20 to 330°C and gradually add LMPAEK pellets through the feed port of the melt extruder 20. When the melt output stabilizes, stop the screw. Then install the film extrusion die 19 at the extruder outlet and begin the next stage.

[0070] Phase 2: Production The winding device 26 is turned on, and the fiber travel speed is set at 1.5 m / min. As the fiber passes through the impregnation tank 14, it absorbs the LMPAEK resin powder particles in the suspension. Heat in the high-temperature furnace 13 volatilizes and removes low-boiling-point components, further molten resin impregnates the internal fibers, and then is initially compacted by the high-temperature pressing roller 17 at a pressure of 1-2 MPa. During this period, the screw speed of the melt extruder 20 is adjusted to maintain a glue output of 35 ± 1 g / min. The fiber strip is then coated by the film extrusion die 19.

[0071] The fiber tape, carrying the molten resin, enters the melt impregnation mold 21, where the mold's wavy surface squeezes the fibers, achieving secondary impregnation of the tape. The tape is then cooled and solidified by the cooling and setting system 22 at a cooling rate of 50°C / min. Finally, the edge trimming system 23 removes defects from both sides of the tape. The main material is guided by the fifth guide roller 25 and then reeled up by the winding device 26, resulting in a 130mm wide thermoplastic prepreg product (i.e., CF / LMPAEK prepreg tape).

[0072] Example 3 The product prepared in this embodiment is a CF / PPS prepreg tape, and its production process includes the following two stages.

[0073] Phase 1: Production preparation First, 18 rolls of 3K tow carbon fiber (T300 model) are installed on creel 1. The fiber is pulled from the creel and passes through the unwinding device 2, the first guide roller 3, the tensioning roller 4, the second guide roller 6, the impregnation tank 14, the third guide roller 12, the high-temperature furnace 13, the high-temperature pressing roller 17, the fourth guide roller 18, the film extrusion die 19, the melt impregnation mold 21, the cooling and setting system 22, the edge trimming system 23, the fifth guide roller 25, and the winding device 26. After the fiber is unwound, the tensioning roller 4 is opened and a tension of 30 to 45 N is applied to the fiber to straighten it. Simultaneously, the unwinding device 2 is activated and its opening and closing angles are adjusted to eliminate noticeable gaps between the yarns. The evenly unwound yarn has a width of 145 mm.

[0074] Subsequently, the high-temperature furnace 13, high-temperature pressure roller 17, and melt impregnation mold 21 were preheated to 340°C, 120°C, and 300°C, respectively. Simultaneously, water flow began to the cooling and setting system 22 in preparation for cooling. The prepared suspension was added to the impregnation tank (20 L) and the feed tank (20 L). The ultrasonic device 9 in the impregnation tank 14 and the mechanical stirring device in the feed tank 5 were activated to maintain a stable suspension system.

[0075] The suspension was prepared by uniformly mixing 10 parts of ethanol, 10 parts of acetone, 0.5 parts of polyvinyl alcohol with a molecular weight of 600, 1 part of polyethylene glycol with a molecular weight of 600, and 0.5 parts of sodium lauryl sulfate. The mixture was then added with 1 part of PPS resin powder and stirred thoroughly until the powder was completely wetted. The mixture was then added to 77 parts of water and stirred thoroughly until uniformly dispersed to obtain approximately 40 L of a water-based suspension.

[0076] Prepare the melt extruder. Set the temperature of the melt extruder 20 to 310°C and gradually add PPS pellets from the feed port of the melt extruder 20. When the melt output stabilizes, stop the screw and install the film extrusion die 19 at the extruder outlet before starting the next stage.

[0077] Phase 2: Production Turn on the winding device 26, setting the fiber's travel speed to 1.5 m / min. As the fiber passes through the impregnation tank 14, it absorbs the PPS resin powder particles in the suspension. Heat in the high-temperature furnace 13 volatilizes and removes low-boiling-point components, further molten resin impregnates the internal fibers, and then is initially compacted by the high-temperature pressure roller 17 at a pressure of 1-2 MPa. During this period, the screw speed of the melt extruder 20 is adjusted to maintain a glue output of 35 ± 1 g / min. The fiber strip is then coated by the film extrusion die 19.

[0078] The fiber tape, carrying the molten resin, enters the melt impregnation mold 21, where the mold's wavy surface squeezes the fibers, achieving secondary impregnation of the tape. The tape is then cooled and solidified by the cooling and setting system 22 at a cooling rate of 50°C / min. Finally, the edge trimming system 23 removes defects from both sides of the tape. The main material is guided by the fifth guide roller 25 and then reeled up by the winding device 26, resulting in a 130mm wide thermoplastic prepreg product (i.e., CF / PPS prepreg tape).

[0079] The prepregs prepared in Examples 1-3 were sampled and tested. The results showed that these prepregs all had a sandwich structure (cross-section as shown in FIG. Figure 4 As shown, the middle fiber layer has a relatively low resin content, while the upper and lower layers are resin-rich layers 104 with high resin content. This demonstrates that the prepreg tape produced using the system and process described herein forms a thick weld layer 220 between the tapes, which helps to enhance the bonding strength between prepreg layers and is suitable for automated placement technology.

Claims

1. A high-performance thermoplastic prepreg production system, characterized by: The production system includes a pay-off device, an impregnation tank, a heating and melting device, a laminating device, and a melt impregnation mold arranged in sequence along the direction of fiber movement; a fiber roll is installed on the pay-off device to provide fiber for production; the impregnation tank is filled with a thermoplastic resin suspension, and the fiber absorbs thermoplastic resin particles when passing through the impregnation tank; the laminating device is filled with molten thermoplastic resin for laminating the fiber.

2. The production system according to claim 1, wherein: An impregnation guide roller and an ultrasonic device are arranged at the bottom of the impregnation tank, and the fiber passes between the impregnation guide roller and the ultrasonic device.

3. The production system according to claim 1, wherein: The production system also includes an impregnation feeding component, which includes a feeding barrel, a concentration adjustment barrel, and a raw material supply system. The feeding barrel is connected to the impregnation glue tank and the concentration adjustment barrel respectively, and the concentration adjustment barrel is connected to the impregnation glue tank and the raw material supply system respectively.

4. The production system according to claim 1, wherein: The heating and melting device is specifically a high-temperature furnace with electric infrared heating, and the heating temperature of the high-temperature furnace is 400-450°C.

5. The production system according to claim 4, wherein: The production system also includes a high-temperature pressing roller arranged between the high-temperature furnace and the laminating device. The high-temperature pressing roller includes at least one pair of electrically heated rollers and the spacing between the rollers is adjustable. The heating temperature of the high-temperature pressing roller is 150~200℃.

6. The production system according to claim 1, wherein: The laminating device comprises an extrusion die head and a melt extruder. After the thermoplastic resin enters the melt extruder, it is melted and extruded from the extrusion die head and adheres to the fiber to complete the laminating process.

7. The production system according to claim 1, wherein: The melt impregnation mold includes a matching mold A and a mold B, the relative molding surfaces of the two are continuous wavy surfaces, and the heating temperature of the melt impregnation mold is 350°C~400°C.

8. The production system according to claim 1, wherein: The production system further comprises a cooling and shaping system, a side material cutting system, a side material recycling system, and a winding device, which are sequentially arranged along the fiber movement direction and located downstream of the melt impregnation mold.

9. A method for producing high-performance thermoplastic prepreg, characterized in that The method includes: the fiber passes through a yarn spreading device and a tension adjustment roller in sequence and then enters an impregnation tank; the fiber absorbs thermoplastic resin particles in the suspension in the impregnation tank and then passes through a high-temperature furnace, a high-temperature pressure roller, an extrusion die, a melt impregnation mold, a cooling and shaping system, and an edge material cutting system in sequence, and finally the product is wound up by a winding device.

10. The method according to claim 9, wherein: The suspension comprises 1 wt% to 50 wt% of high-performance thermoplastic resin powder, 50 wt% to 99 wt% of deionized water, 0.01 wt% to 5 wt% of surfactant, and 1 wt% to 5 wt% of dispersant, wherein the thermoplastic resin powder is selected from at least one of PI, PEI, PEEK, PAEK, PEKK, LMPAEK, and PPS, and the surfactant is selected from sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate, polyoxyethylene stearate, polyoxyethylene octanol ether, hexadecyl trimethylolpropane, and the like. At least one of ammonium bromide, sodium docusate, ceteareth-25, dimethylformamide, and polyethylene glycol octylphenyl ether; the dispersant is selected from at least one of ethanol, acetone, nonionic water-soluble cellulose, nonionic water-soluble hydroxypropyl methylcellulose, polyvinyl pyrrolidone, polyvinyl alcohol, polyethylene glycol, polyethylene glycol monostearate, hydroxymethylcellulose polyethylene glycol, polyvinyl pyrrolidone, and hydroxyethyl cellulose; the molten thermoplastic resin poured onto the fiber from the extrusion die is the same as the thermoplastic resin selected for preparing the suspension.

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