Production line for the preparation of thermoplastic dry prepreg yarn

Abstract

This utility model discloses a production line for preparing thermoplastic dry-process prepreg yarn. The production line includes a fiber unwinding area, a fiber spreading area, an impregnation area, a drying area, a cooling area, and a winding area arranged sequentially. The fiber to be processed passes around each yarn frame of the rotating yarn frame assembly. A tension detector is used to acquire the current unwinding tension of the fiber to be processed in real time. The fiber spreading area is equipped with a first yarn guide roller assembly and an electrostatic elimination device. After the fiber to be processed passes through the rotating yarn frame assembly, it passes around the first yarn guide roller assembly. The impregnation area is equipped with a second yarn guide roller assembly and an impregnation tank containing water-based resin. The cooling area is equipped with a fourth yarn guide roller assembly, a cooling roller assembly, and a ring blowing device. The winding area is equipped with a fifth yarn guide roller assembly, a winding roller, a winding drive component connected to the winding roller, and a data acquisition component. This improves the preparation effect of thermoplastic dry-process prepreg yarn.

Description

Technical Field

[0001] This utility model relates to the field of thermoplastic composite prepreg preparation technology, specifically to a production line for preparing thermoplastic dry prepreg yarn based on high-performance fiber-impregnated water-soluble polyurethane resin. Background Technology

[0002] In the field of thermoplastic composite prepreg preparation, traditional wet processes use organic solvents (such as acetone) to dilute the resin, resulting in 0.5-1.2% volatile organic compounds (VOCs) remaining in the prepreg, which is highly polluting and can cause porosity defects during composite molding. Furthermore, traditional wet processes utilize high-temperature and high-pressure equipment for preparation via melt impregnation or roll impregnation. However, traditional wet process production lines have the following problems: Existing technologies using melt impregnation require high-temperature and high-pressure equipment, which requires heating the resin to 200-300°C. This can easily lead to oxidative damage at the interface of high-performance fibers (such as carbon fibers), resulting in a 15-20% loss in tensile strength, and the resin has poor permeability. Traditional roller impregnation methods are prone to producing a "racetrack effect" due to the high viscosity of the resin, resulting in a resin content in the fiber bundle core that is 40-60% lower than that on the surface. The melt viscosity of thermoplastic resins is usually >5000 Pa·s, and the existing technology has a fiber spread width of less than 120% of the original diameter, which makes it impossible for the resin to fully impregnate the fiber. Traditional processes suffer from tension fluctuations (±5N), resulting in fiber density deviations of >15% and final product thickness tolerances of ±10%. This leads to poor process continuity and significant quality fluctuations.

[0003] In summary, existing dry prepreg technologies are mostly limited to thermosetting resin systems. Traditional wet impregnation processes suffer from technical defects such as solvent residue, high energy consumption, and uneven resin distribution. Melt impregnation requires high-temperature and high-pressure equipment, which can easily lead to fiber damage and poor resin permeability. Utility Model Content

[0004] Therefore, this utility model provides a production line for preparing thermoplastic dry prepreg yarn to solve at least one of the above-mentioned technical problems.

[0005] To achieve the above objectives, the present invention provides the following technical solution: This utility model provides a production line for preparing thermoplastic dry prepreg yarn, comprising a fiber unwinding area, a fiber spreading area, an impregnation area, a drying area, a cooling area, and a winding area arranged sequentially; wherein: The fiber unwinding area is equipped with a rotary yarn frame assembly, an unwinding drive unit that is connected to the active yarn frame in the rotary yarn frame assembly, and a tension detector; the fiber to be processed bypasses each yarn frame of the rotary yarn frame assembly; The fiber unfolding area is provided with a first yarn guide roller group and an electrostatic elimination device. After the fiber to be processed is wound out of the rotary yarn frame group, it passes around the first yarn guide roller group. The impregnation area is provided with a second yarn guide roller group and an impregnation tank containing water-based resin. After the fiber to be treated is wound out from the first yarn guide roller group, it passes around the second yarn guide roller group and passes above the impregnation tank. An impregnation roller is provided above the impregnation tank. A part of the impregnation roller is immersed in the impregnation tank. As the impregnation roller rotates, the water-based resin in the impregnation tank is applied to the surface of the fiber to be treated. The drying area is equipped with a third yarn guide roller group. After the fiber to be processed is wrapped around the second yarn guide roller group, it passes around the third yarn guide roller group. The cooling area is equipped with a fourth yarn guide roller group, a cooling roller group and a ring blowing device. After the fiber to be treated is wrapped around the third yarn guide roller group, it passes around each roller of the fourth yarn guide roller group and each roller of the cooling roller group in sequence, and is cooled by air through the ring blowing device. The take-up area is provided with a fifth yarn guide roller group, a take-up roller, a take-up drive component and a data acquisition component that are connected to the take-up roller. After the fiber to be processed is wound out from the fourth yarn guide roller group, it passes around the fifth yarn guide roller group and then winds onto the take-up roller.

[0006] In some embodiments, the unwinding drive is a servo motor.

[0007] In some embodiments, the first yarn guide roller group includes at least three guide rollers with different radii of curvature, the guide rollers being arranged in a spatially staggered manner to form a three-dimensional fiber spreading channel; and / or, The electrostatic eliminator generates an adjustable high-voltage electrostatic field of 0.5-2.0kV.

[0008] In some embodiments, the immersion area is further provided with an ultrasonic-assisted immersion device, wherein the ultrasonic waves emitted by the ultrasonic-assisted immersion device are longitudinal vibration waves with a frequency of 28 kHz.

[0009] In some embodiments, a porous guide plate is provided inside the impregnation tank; And / or, a temperature control device is provided outside the impregnation tank; and / or, A scraper is provided above the impregnation tank, and the scraper has a preset gap with the outer surface of the impregnation roller.

[0010] In some embodiments, the fibers to be treated are sequentially divided into an infrared radiation section, a hot air convection section, and a microwave-assisted section within the drying area. The infrared radiation section is equipped with an infrared radiation heater, the hot air convection section is equipped with a hot air drying oven, and the microwave-assisted section is equipped with a microwave dryer.

[0011] In some embodiments, the infrared radiation power density of the infrared radiation section is 3-5 W / cm², the wind speed of the hot air convection section is 0.8-1.5 m / s, the temperature gradient is 80℃→120℃→90℃, and the microwave frequency of the microwave auxiliary section is 2.45 GHz, with a microwave radiation power density less than or equal to 10 kW / m³.

[0012] In some embodiments, the cooling roller assembly includes at least two cooling rollers, the interior of which is circulated with a 5-10°C coolant, and the surface of the cooling rollers is provided with an array of micro-protrusions; the ring blowing device injects nitrogen gas at a pressure of 0.3-0.6 MPa.

[0013] In some embodiments, the data acquisition component includes: A tension sensor is used to collect the current winding tension of the fiber to be processed in the winding area in real time. An infrared thickness gauge is used to collect the thickness value of the fiber to be processed before winding. An X-ray inspection instrument is used to collect surface defects of the fiber to be treated before winding.

[0014] In one or more of the above specific embodiments, the preparation production line and preparation method provided by this utility model have at least the following technical effects: 1. This utility model adopts a three-stage dehydration process in the drying zone. The infrared radiation section is used to quickly break the surface hydration layer, and then the hot air convection section is used to perform gradient heating to evaporate free water. Finally, the microwave-assisted section is used to directionally remove bound water, so that the final moisture content is <0.05%, completely eliminating the porosity problem caused by solvent evaporation. 2. This utility model uses a double-helix cooling roller combined with a cooling zone and nitrogen ring blowing to make the fiber to be treated undergo a rapid cooling process in the temperature field, which significantly improves the strength retention rate of carbon fiber. 3. This utility model sets up a porous guide plate in the impregnation tank to form a turbulent flow field (Reynolds number Re > 4000), and with the 28kHz longitudinal vibration wave of the ultrasonic system, the resin penetration depth reaches the monofilament level (SEM observation shows that each fiber surface is covered with a resin layer with a thickness of 2-3μm), and the interfacial shear strength (IFSS) is increased to more than 45MPa. 4. This utility model employs a dielectric barrier electrostatic elimination device in the fiber spreading area to apply a 0.5-2.0kV electrostatic field, thereby forming a uniform charge layer on the surface of the fiber bundle. Combined with the three-dimensional fiber spreading effect of the first yarn guide roller group in the form of a curved surface, it achieves a fiber width expansion rate of 300% (from the original width of 1.2mm of 1K carbon fiber bundle to 3.6mm), an increase in specific surface area of ​​250%, and a shortening of the resin penetration path to the micron level. Attached Figure Description

[0015] To more clearly illustrate the embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0016] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the implementation conditions of this utility model. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that this utility model can produce, should still fall within the scope of the technical content disclosed in this utility model.

[0017] Figure 1 This is a schematic diagram of the production line for preparing thermoplastic dry prepreg yarn provided by this utility model; Figure 2 This is a schematic diagram of the fiber unwinding area in the production line for preparing thermoplastic dry prepreg yarn provided by this utility model. Figure 3 This is a schematic diagram of the fiber unfolding region in the production line for preparing thermoplastic dry prepreg yarn provided by this utility model. Figure 4 This is a schematic diagram of the impregnation zone in the production line for preparing thermoplastic dry prepreg yarn provided by this utility model; Figure 5 This is a schematic diagram of the drying zone in the production line for preparing thermoplastic dry prepreg yarn provided by this utility model; Figure 6 This is a schematic diagram of the cooling zone in the production line for preparing thermoplastic dry prepreg yarn provided by this utility model; Figure 7 This is a schematic diagram of the winding area in the production line for preparing thermoplastic dry prepreg yarn provided by this utility model; Figure 8 SEM image of the resin layer coating thickness of the fibers to be treated in the preparation production line provided by the present invention; Figure 9 An interface diagram showing the experimental results of the interfacial shear strength of the fibers to be treated in the preparation production line provided by the present invention. Figure 10 This is an interface diagram showing the experimental results of the fiber width expansion rate of the fibers to be processed by the preparation production line provided by the present invention.

[0018] Explanation of reference numerals in the attached figures: 100. Fibers to be treated; 10. Fiber unwinding area; 101. Rotary yarn creel assembly; 102. Unwinding drive unit; 103. Photoelectric encoder; 20. Fiber spreading area; 201. First yarn guide roller group; 202. Static electricity elimination device; 30. Infiltrated area; 301. Impregnation tank; 302. Porous guide plate; 303. Temperature control device; 304. Ultrasonic-assisted impregnation device; 40. Drying area; 401. Infrared radiation section; 402. Hot air convection section; 403. Microwave-assisted section; 50. Cooling area; 501. Fourth yarn guide roller group; 502. Cooling roller group; 503. Circular blowing device; 60. Rewinding area; 601. Fifth yarn guide roller group; 602. Take-up roller; 603. Take-up drive component; 604. Infrared thickness gauge; 605. X-ray detector. Detailed Implementation

[0019] The following specific embodiments illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0020] In one specific implementation, such as Figure 1 As shown, the production line for preparing thermoplastic dry prepreg yarn provided by this utility model includes a fiber unwinding area 10, a fiber spreading area 20, an impregnation area 30, a drying area 40, a cooling area 50, a winding area 60, and a controller arranged in sequence.

[0021] Among them, such as Figure 2 As shown, the fiber unwinding area 10 is provided with a rotary yarn frame assembly 101, an unwinding drive 102 connected to the active yarn frame in the rotary yarn frame assembly 101, and a tension detector; the fiber to be processed 100 bypasses each yarn frame of the rotary yarn frame assembly 101, and the tension detector is used to obtain the current unwinding tension of the fiber to be processed 100 in real time.

[0022] In a specific application scenario, the fiber unwinding area 10 includes a rotary yarn frame and an intelligent tension control system. The rotary yarn frame is equipped with a photoelectric encoder 103, which is used to monitor the yarn unwinding speed in real time. The tension control system is a closed-loop feedback system consisting of an unwinding drive 102 and a tension detector, which ensures that the fiber tension fluctuation is controlled within ±1N. If the tension detector detects that the fiber tension value fluctuation is greater than the normal range, it will feed back to the servo motor. If the tension is high, the servo motor will quickly rotate forward to achieve unwinding and stabilize the tension. If the tension value is low, the servo motor will rotate in reverse to achieve yarn winding and stabilize the tension value.

[0023] like Figure 3 As shown, the fiber spreading area 20 is equipped with a first yarn guide roller group 201 and an electrostatic elimination device 202. The fiber 100 to be processed, after exiting the rotating yarn frame group 101, passes around the first yarn guide roller group 201. Specifically, the fiber spreading area 20 is equipped with a first yarn guide roller group 201 in the form of a curved array and an electrostatic elimination device 202 of dielectric barrier discharge type. The electrostatic elimination device 202 is connected to the roller closest to the first yarn guide roller group 201 via a mounting plate to reduce the influence of electrostatic effects during the transmission of carbon fiber bundles. To spread the carbon fiber bundles more evenly during the spreading process, the yarn guide roller group includes at least three sets of ceramic guide rollers with different radii of curvature. For example, the radii of the ceramic rollers can be 20mm, 25mm, and 30mm, respectively. The ceramic guide rollers are arranged in a spatially staggered manner to form a three-dimensional fiber spreading channel. Combined with the synergistic effect of an adjustable high-voltage electrostatic field of 0.5-2.0kV, the fiber bundle width expansion rate reaches 150%-300%.

[0024] like Figure 4 As shown, the above-mentioned impregnation area 30 is provided with a second yarn guide roller group and an impregnation tank 301 containing water-based resin. After the fiber to be treated 100 is wound out from the first yarn guide roller group 201, it passes around the second yarn guide roller group and passes above the impregnation tank 301. An impregnation roller is provided above the impregnation tank. A part of the impregnation roller is immersed in the impregnation tank. As the impregnation roller rotates, the water-based resin in the impregnation tank is applied to the surface of the fiber to be treated. A scraper is provided above the impregnation tank. The scraper has a preset gap with the outer surface of the impregnation roller. Specifically, the impregnation area 30 includes an impregnation tank 301 and an ultrasonic auxiliary system. A porous guide plate 302 is provided in the impregnation tank 301 to form a resin turbulence field. The tank is equipped with a temperature control device 303 to maintain the resin temperature in the range of 35-45℃. The ultrasonic system generates longitudinal vibration waves at a frequency of 28kHz, so that the resin solid content is stabilized at 25±1% and the dynamic viscosity is maintained at 800-1200mPa·s.

[0025] In actual use, the lower half of the impregnation roller is immersed in the resin in the impregnation tank. As the impregnation roller rotates, it carries the resin to the fiber surface. Since the impregnation roller carries too much resin during the immersion process, a scraper is used to scrape off the excess resin, thereby making the fiber impregnation more uniform. It should be understood that the preset gap between the scraper and the impregnation roller is used to allow the necessary thickness of resin to pass through, and this preset gap can be set as needed.

[0026] Specifically, the waterborne resin can be a waterborne polyurethane resin with a solid content of 20%-28%, or a waterborne acrylate or polyester emulsion system can be used to replace polyurethane. By adjusting the type of emulsifier (such as nonionic surfactant), a similar low-temperature wetting effect can be achieved while maintaining nanoscale dispersion characteristics. Alternatively, a thermoplastic elastomer (TPE) and a low-melting-point polyolefin blend system can be used to replace the waterborne resin through a melt extrusion coating process. In this case, a more precise temperature control module (±1℃) is required.

[0027] like Figure 5 As shown, the drying zone 40 is equipped with a third yarn guide roller group. The fiber 100 to be processed passes through the second yarn guide roller group and then around the third yarn guide roller group. Specifically, the drying zone 40 adopts a multi-stage gradient temperature control tunnel, including an infrared radiation section 401, a hot air convection section 402, and a microwave auxiliary section 403. The infrared section has a power density of 3-5 W / cm², the hot air section has a wind speed of 0.8-1.5 m / s and a temperature gradient of 80℃→120℃→90℃, and the microwave section has a frequency of 2.45 GHz and a power density not exceeding 10 kW / m³, achieving a moisture evaporation rate >1.2 kg / (m²·h).

[0028] Specifically, the infrared radiation section is equipped with an infrared radiation heater, the hot air convection section is equipped with a hot air drying oven, and the microwave auxiliary section is equipped with a microwave dryer; the infrared radiation heater in the infrared radiation section directly heats the material surface by emitting infrared rays of a specific wavelength, thereby achieving rapid temperature rise.

[0029] The hot air convection section is equipped with a hot air drying oven, which can be used to dry the impregnated carbon fiber. The hot air convection transfers heat to the material to remove excess solvent and water, allowing the resin to initially cure.

[0030] The microwave-assisted section is equipped with a microwave dryer, which uses microwave energy to penetrate the interior of the material to achieve efficient molecular-level heating, reducing drying time and improving curing quality.

[0031] like Figure 6As shown, the cooling zone 50 is equipped with a fourth yarn guide roller group 501, a cooling roller group 502, and a ring blowing device 503. After the fiber 100 to be treated exits from the third yarn guide roller group, it sequentially passes around each roller of the fourth yarn guide roller group 501 and each roller of the cooling roller group 502, and is cooled by air through the ring blowing device 503. Specifically, the cooling zone 50 is equipped with a double-helix cooling roller group 502 and an inert gas ring blowing device 503. The cooling roller group 502 includes two cooling rollers, and the cooling rollers are filled with a 5-10℃ circulating coolant. The surface of the cooling rollers is provided with a micro-protrusion array to increase the heat exchange area. The ring blowing device 503 sprays nitrogen gas at a pressure of 0.3-0.6MPa, causing the surface temperature of the prepreg yarn to drop rapidly from 80℃ to 25±3℃ within 0.5-2 seconds.

[0032] Furthermore, such as Figure 7 As shown, the take-up area 60 is provided with a fifth yarn guide roller group 601, a take-up roller 602, a take-up drive component 603 connected to the take-up roller 602, and a data acquisition component. After the fiber 100 to be processed is wound out from the fourth yarn guide roller group 501, it passes around the fifth yarn guide roller group 601 and then winds onto the take-up roller 602. The data acquisition component is used to collect the status data of the fiber 100 to be processed in real time during the take-up process.

[0033] Specifically, the winding area 60 includes a constant linear speed winding mechanism and an online quality monitoring system. The winding mechanism uses differential planetary gear transmission, combined with a tension sensor to achieve torque control at the 0.01 N·m level. This online inspection system uses both infrared and X-rays to check product quality. Infrared light measures material thickness in real time, while X-rays, like a CT scan, detect internal defects such as bubbles and cracks. The two sets of inspection data are merged and analyzed instantly. An alarm is immediately triggered if a thickness deviation exceeds 5% or a defect the size of a sesame seed (above 0.005 cubic millimeters) is detected, and an inspection report containing the location and severity of the problem is automatically generated. The system has a built-in emergency fault mode; even if one inspector malfunctions, the other can continue operating, ensuring the production line remains uninterrupted. The inspection accuracy reaches 1 / 60th the thickness of a human hair, and the inspection results are directly connected to the factory management system to help quickly control product quality.

[0034] The controller is used to receive the current unwinding tension detected by the tension detector, and generate an unwinding adjustment command based on the relationship between the current unwinding tension and a pre-stored preset unwinding tension. The unwinding adjustment command is used to control the output speed of the unwinding drive 102. The controller is also used to receive the status data detected by the data acquisition component, and generate a status adjustment command and / or generate a quality monitoring result based on the status data.

[0035] In a specific application scenario, the controller provided by this utility model is a PLC control system. The roller is driven to rotate by a motor. During the operation of the winding equipment, the tension detection device of the winding equipment feeds back the detected prepreg tension value to the PLC system. In the human-machine interface, the range of prepreg tension (15-20N) is preset, and the detected tension value is compared with the preset range. When the tension detection value exceeds the preset range, the PLC will send a signal to stop the winding equipment. The tension adjustment mechanism motor will be started and the tension will be adjusted by forward and reverse rotation to keep the prepreg tension within the preset range.

[0036] During operation, the yarn to be processed is unwound from the rotary yarn frame group 101 in the yarn unwinding area. The unwinding drive 102 adjusts the unwinding speed according to the tension detected by the tension detector. The yarn enters the yarn unfolding area, is unfolded by the first yarn guide roller group 201, and static electricity is eliminated by the static elimination device 202. The yarn enters the impregnation area 30, passes around the second yarn guide roller group and over the impregnation tank 301, and is impregnated with thermoplastic resin. After impregnation, the yarn enters the drying area 40, and is dried by passing through the infrared radiation section 401, the hot air convection section 402 and the microwave-assisted section 403 in sequence by the third yarn guide roller group. The dried yarn enters the cooling area 50, passes around the fourth yarn guide roller group 501 and the cooling roller group 502, and is air-cooled by the ring blowing device 503. The yarn enters the winding area 60, passes around the fifth yarn guide roller group 601 and is wound onto the winding roller 602. The data acquisition component collects status data in real time.

[0037] This production line enables continuous yarn processing, improving production efficiency. Tension detection and adjustment ensure stable yarn tension during unwinding and winding, while the static elimination device 202 effectively prevents fiber entanglement caused by static electricity during unwinding. Multi-stage drying and cooling processes ensure rapid curing of the yarn after impregnation, while avoiding heat damage. The data acquisition component monitors the yarn status in real time, facilitating timely detection and handling of quality issues.

[0038] In some embodiments, the unwinding drive 102 is a servo motor; the controller receives the current unwinding tension detected by the tension detector and calculates the fluctuation value between the current unwinding tension and the unwinding tension at the previous moment; when the fluctuation value is greater than the maximum value of the preset tension fluctuation range or less than the minimum value of the preset tension fluctuation range, the controller generates an unwinding adjustment command, which is used to start the servo motor; when the servo motor is in the started state, if the current unwinding tension is greater than the maximum value of the preset tension fluctuation range, the servo motor is controlled to rotate forward to unwind; if the current unwinding tension is less than the minimum value of the preset tension fluctuation range, the servo motor is controlled to rotate in reverse to rewind.

[0039] Servo motors can precisely control the unwinding speed, offering fast response and high adjustment accuracy. Real-time monitoring and adjustment of the floating value further improves the stability of yarn tension. Alternatively, variable frequency motors can be used instead of servo motors, reducing costs while maintaining a certain level of adjustability.

[0040] In addition, pneumatic closed-loop control or AI predictive control can also be used. Pneumatic closed-loop control uses a pneumatic servo valve (response time <10ms) to replace the magnetic powder brake, and combines it with a pressure sensor to achieve dynamic tension compensation, which can further reduce the fluctuation range to ±0.3N. AI predictive control integrates machine learning algorithms to analyze the yarn movement trajectory, predict the tension change trend, and adjust the unwinding speed in advance to reduce the mechanical lag of the floating roller.

[0041] In some embodiments, the first guide roller group 201 includes at least three guide rollers with different radii of curvature, which are arranged in a spatially staggered manner to form a three-dimensional fiber spreading channel; the high-voltage electrostatic field generated by the static elimination device 202 is an adjustable electrostatic field of 0.5-2.0kV. In this way, the three-dimensional fiber spreading channel can better spread the yarn, reduce fiber entanglement, and the adjustable electrostatic field can be flexibly adjusted according to the static condition of the yarn, improving the static elimination effect.

[0042] It should be understood that in practical applications, the number and complexity of the guide roller assembly can be increased to further optimize the fiber spreading effect. An ion fan can be used instead of a high-voltage electrostatic field to provide a more uniform static elimination effect. Mechanical vibration or airflow-assisted fiber spreading can also be used. In mechanical vibration spreading, a piezoelectric ceramic vibrator (frequency 1-5kHz) is embedded in the first guide roller assembly 201. High-frequency micro-amplitude vibration assists fiber spreading, replacing the static elimination device 202, and the fiber spreading width expansion rate can reach 200%. In airflow-assisted fiber spreading, a high-pressure airflow nozzle (0.2-0.5MPa) is added to the gap between the guide rollers. The shear force of laminar gas is used to disperse the fiber bundle, which is suitable for the uniform spreading of high-modulus fibers (such as carbon fibers).

[0043] In some embodiments, the impregnation area 30 is further provided with an ultrasonic-assisted impregnation device 304, the ultrasonic waves emitted by the ultrasonic-assisted impregnation device 304 being longitudinal vibration waves with a frequency of 28 kHz. Ultrasonic waves can promote better penetration of the resin into the yarn, improving the impregnation effect. The impregnation effect can also be optimized by adjusting the ultrasonic frequency and power, or the impregnation efficiency can be improved by increasing the number of ultrasonic devices.

[0044] A porous guide plate 302 is installed inside the impregnation tank 301, and a temperature control device 303 is installed outside the impregnation tank 301. The porous guide plate 302 enables more uniform resin flow and improves impregnation quality, while the temperature control device 303 can precisely control the temperature inside the impregnation tank 301 to ensure stable resin performance. It should be understood that using guide plates of different shapes and pore sizes can further optimize resin flow, increase the insulation of the impregnation tank 301, and reduce heat loss.

[0045] Alternatively, high-pressure jet impregnation or vacuum-assisted impregnation can be used. In high-pressure jet impregnation, a multi-hole nozzle array (orifice diameter 50-100μm) is used to vertically spray resin atomized droplets (particle size <10μm) onto the fiber bundle, replacing impregnation tank 301, which improves resin penetration efficiency by 30%. In vacuum-assisted impregnation, a negative pressure environment of -0.08 to -0.1MPa is applied in a closed cavity, which promotes the resin to quickly fill the gaps between fibers, eliminating the need for an ultrasonic system and reducing the resin viscosity requirements.

[0046] In some embodiments, the fibers to be treated are sequentially divided into an infrared radiation section, a hot air convection section, and a microwave-assisted section within the drying area. The infrared radiation section is equipped with an infrared radiation heater, the hot air convection section is equipped with a hot air drying oven, and the microwave-assisted section is equipped with a microwave dryer. Specifically, the infrared radiation power density of the infrared radiation section 401 is 3-5 W / cm², the air velocity of the hot air convection section 402 is 0.8-1.5 m / s, and the temperature gradient is 80℃→120℃→90℃. The microwave frequency of the microwave-assisted section 403 is 2.45 GHz, and the microwave radiation power density is less than or equal to 10 kW / m³.

[0047] In addition, radio frequency (RF) drying or pulsed hot air drying can also be used for drying. During RF drying, a 13.56MHz RF generator produces an alternating electric field, causing frictional heating of the resin's polar molecules, replacing the infrared radiation band 401, reducing energy consumption by 40% and providing better drying uniformity. During pulsed hot air drying, intermittent high-speed airflow (wind speed 2-3m / s, frequency 0.5-2Hz) impacts the surface of the prepreg, shortening the moisture evaporation time, making it suitable for high-solids-content resin systems.

[0048] In some embodiments, the cooling roller assembly 502 includes at least two cooling rollers, the interior of which is circulated with a 5-10°C coolant, and the surface of the cooling rollers is provided with a micro-bump array; the ring-blowing device 503 sprays nitrogen gas at a pressure of 0.3-0.6 MPa. Alternatively, liquid nitrogen spray quenching or a contact cooling plate can be used; wherein, in liquid nitrogen spray quenching, a liquid nitrogen spray system (flow rate 0.5-1.5 L / min) is arranged on the surface of the cooling rollers to cool the prepreg to below 20°C within 0.1-0.3 seconds, inhibiting resin crystalline phase separation; in the contact cooling plate, a microchannel cooling copper plate (thermal conductivity > 400 W / m·K) is directly pressed onto the surface of the prepreg, replacing the gas ring-blowing device 503, increasing the cooling efficiency by 50%.

[0049] Specifically, the data acquisition component includes a tension sensor, an infrared thickness gauge 604, and an X-ray detector 605; wherein, the tension sensor is used to acquire the current winding tension of the fiber to be processed 100 in the winding area 60 in real time, the infrared thickness gauge is used to acquire the thickness value of the fiber to be processed 100 before winding, and the X-ray detector 605 is used to acquire the surface defects of the fiber to be processed 100 before winding.

[0050] In addition, magnetic levitation synchronous winding or optical in-situ monitoring can also be used; when magnetic levitation synchronous winding is used, a non-contact magnetic coupler is used to replace the planetary gear transmission to achieve torque control with zero mechanical wear (accuracy ±0.005N·m); when optical in-situ monitoring is used, a Raman spectrometer is integrated to analyze the resin curing degree in real time, replacing the X-ray detector 605, avoiding radiation pollution and achieving a resolution of 1μm.

[0051] This utility model also provides a method for preparing thermoplastic dry prepreg yarn, comprising the following steps: S1: The fiber to be treated 100 is installed on the rotary yarn frame assembly 101, and the unwinding drive 102 is started, and the fiber begins to be unwound; during the unwinding process, the unwinding tension of the fiber is monitored in real time by a tension detector, and the data is transmitted to the controller. The controller generates an unwinding adjustment command based on the tension fluctuation value, and adjusts the rotation speed and rotation direction of the unwinding drive 102 to ensure that the fiber to be treated 100 is unwound with a stable tension; S2: After the fiber 100 to be processed is unwound from the unwinding area, it passes through the first yarn guide roller group 201 and is unfolded in the three-dimensional fiber unfolding channel formed by the first yarn guide roller group 201; during the unfolding process, the static elimination device 202 is activated to generate a high voltage static field and eliminate static electricity on the fiber surface. S3: After the fiber 100 to be treated is wound out from the unfolding area, it enters the impregnation tank 301 above the second yarn guide roller group and is impregnated by the water-based resin in the impregnation tank 301; during the impregnation process, the porous guide plate 302 guides the resin flow to ensure uniform fiber impregnation, and ultrasonic-assisted impregnation is activated; the impregnation temperature is 35-45℃ low-temperature impregnation, and the dynamic viscosity of the water-based polyurethane resin is 800-1200mPa·s; S4: After the fiber 100 to be treated exits from the impregnation area 30, it sequentially enters the infrared radiation section 401, the hot air convection section 402, and the microwave-assisted section 403 of the drying area 40. Upon entering the infrared radiation section 401, the infrared radiation heater is activated to perform preliminary drying of the fiber, with an infrared radiation power density of 3-5 W / cm². Upon entering the hot air convection section 402, the hot air drying oven is activated, with an air velocity of 0.8-1.5 m / s and a temperature gradient of 80℃→120℃→90℃, to further dry the fiber. Upon entering the microwave-assisted section 403, the microwave dryer is activated, with a frequency of 2.45 GHz and a power density less than or equal to 10 kW / m³, to ensure complete drying of the fiber. S5: After the fiber 100 to be treated exits from the drying area 40, it passes sequentially through the first roller of the fourth yarn guide roller group 501, the first roller of the cooling roller group 502, the second roller of the fourth yarn guide roller group 501, the first roller of the cooling roller group 502, and the third roller of the fourth yarn guide roller group 501. The cooling rollers reduce the fiber temperature through a circulating cooling liquid at 5-10℃, and the micro-bump array increases the cooling efficiency. The ring blowing device 503 is started, and nitrogen gas is injected at a pressure of 0.3-0.6MPa. The nitrogen gas is used to air-cool the fiber, so that the fiber 100 to be treated undergoes a rapid cooling process from 45℃ to 25℃, with a cooling rate >30℃ / s. S6: After the fiber 100 to be processed is wound out from the cooling area 50, it is wound onto the take-up roller 602 through the fifth guide roller group 601. The take-up drive 603 is started to evenly wind the fiber onto the take-up roller 602. During the winding process, the data acquisition component collects fiber status data in real time and transmits the data to the controller. The controller generates status adjustment instructions or quality monitoring results based on the collected data.

[0052] In one or more of the above specific embodiments, the preparation production line and preparation method provided by this utility model have at least the following technical effects: 1. This utility model adopts a three-stage dehydration process using water-based polyurethane resin in a drying zone 40. The infrared radiation section 401 is used to quickly break the surface hydration layer, and then the hot air convection section 402 is used to perform gradient heating to evaporate free water. Finally, the microwave-assisted section 403 is used to directionally remove bound water, so that the final moisture content is <0.05%, completely eliminating the porosity problem caused by solvent evaporation. 2. This utility model uses low-temperature impregnation at 35-45℃ in the impregnation zone 30 (resin dynamic viscosity 800-1200mPa·s), combined with the double-helix cooling roller and nitrogen ring blowing in the cooling zone 50, to make the fiber to be treated 100 undergo a rapid cooling process from 45℃ to 25℃ (cooling rate > 30℃ / s), which significantly improves the carbon fiber strength retention rate. 3. This invention uses a porous guide plate 302 in the impregnation tank to create a turbulent flow field (Reynolds number Re > 4000), which, combined with the 28kHz longitudinal vibration wave of the ultrasonic system, allows the resin penetration depth to reach the monofilament level (e.g., Figure 8 The image shows SEM observations revealing a resin layer 2-3 μm thick covering the surface of each fiber. Figure 9 As shown, the interfacial shear strength (IFSS) is increased to over 45 MPa; 4. This utility model employs a dielectric barrier electrostatic elimination device 202 in the fiber spreading region 20 to apply a 0.5-2.0kV electrostatic field, causing a uniform charge layer to form on the fiber bundle surface. Combined with the three-dimensional fiber spreading effect of the curved first yarn guide roller group 201, a fiber width expansion rate of 300% is achieved (e.g., Figure 10 As shown, the original width of the 1K carbon fiber bundle was expanded from 1.2mm to 3.6mm, the specific surface area increased by 250%, and the resin penetration path was shortened to the micron level; 5. This utility model improves the product's automation level and quality monitoring level by controlling the tension fluctuation in the unwinding area and cooperating with the online monitoring system in the winding area 60.

[0053] The above specific embodiments further illustrate the purpose, technical solution, and beneficial effects of this utility model. It should be understood that the above are only specific embodiments of this utility model and are not intended to limit the scope of protection of this utility model. Any modifications, equivalent substitutions, improvements, etc., made on the basis of the technical solution of this utility model should be included within the scope of protection of this utility model.

Claims

1. A production line for the preparation of thermoplastic dry preimpregnated yarns, characterized by, It includes a fiber unwinding area, a fiber spreading area, an impregnation area, a drying area, a cooling area, and a winding area arranged sequentially; wherein: The fiber unwinding area is equipped with a rotary yarn frame assembly, an unwinding drive unit that is connected to the active yarn frame in the rotary yarn frame assembly, and a tension detector; the fiber to be processed bypasses each yarn frame of the rotary yarn frame assembly; The fiber unfolding area is provided with a first yarn guide roller group and an electrostatic elimination device. After the fiber to be processed is wound out of the rotary yarn frame group, it passes around the first yarn guide roller group. The impregnation area is provided with a second yarn guide roller group and an impregnation tank containing water-based resin. After the fiber to be treated is wound out from the first yarn guide roller group, it passes around the second yarn guide roller group and passes above the impregnation tank. An impregnation roller is provided above the impregnation tank. A part of the impregnation roller is immersed in the impregnation tank. As the impregnation roller rotates, the water-based resin in the impregnation tank is applied to the surface of the fiber to be treated. The drying area is equipped with a third yarn guide roller group. After the fiber to be processed is wrapped around the second yarn guide roller group, it passes around the third yarn guide roller group. The cooling area is equipped with a fourth yarn guide roller group, a cooling roller group and a ring blowing device. After the fiber to be treated is wrapped around the third yarn guide roller group, it passes around each roller of the fourth yarn guide roller group and each roller of the cooling roller group in sequence, and is cooled by air through the ring blowing device. The take-up area is provided with a fifth yarn guide roller group, a take-up roller, a take-up drive component and a data acquisition component that are connected to the take-up roller. After the fiber to be processed is wound out from the fourth yarn guide roller group, it passes around the fifth yarn guide roller group and then winds onto the take-up roller.

2. The production line for the preparation of thermoplastic dry-process prepreg according to claim 1, characterized in that, The unwinding drive is a servo motor.

3. The production line for the preparation of thermoplastic dry-process pre-impregnated yarn according to claim 1, characterized in that, The first yarn guide roller group includes at least three guide rollers with different radii of curvature, and the guide rollers are arranged in a spatially staggered manner to form a three-dimensional fiber spreading channel; and / or, The electrostatic eliminator generates an adjustable high-voltage electrostatic field of 0.5-2.0kV.

4. The production line for preparing thermoplastic dry prepreg yarn according to claim 1, characterized in that, The immersion area is also equipped with an ultrasonic-assisted immersion device, which emits ultrasonic waves at a frequency of 28 kHz, which are longitudinal vibration waves.

5. The production line for preparing thermoplastic dry prepreg yarn according to claim 1, characterized in that, The impregnation tank is equipped with a porous guide plate; And / or, a temperature control device is provided outside the impregnation tank; and / or, A scraper is provided above the impregnation tank, and the scraper has a preset gap with the outer surface of the impregnation roller.

6. The production line for preparing thermoplastic dry prepreg yarn according to claim 1, characterized in that, The fibers to be processed are divided into an infrared radiation section, a hot air convection section and a microwave-assisted section in the drying area. The infrared radiation section is equipped with an infrared radiation heater, the hot air convection section is equipped with a hot air drying oven, and the microwave-assisted section is equipped with a microwave dryer.

7. The production line for preparing thermoplastic dry prepreg yarn according to claim 6, characterized in that, The infrared radiation power density of the infrared radiation section is 3-5 W / cm², the wind speed of the hot air convection section is 0.8-1.5 m / s, the temperature gradient is 80℃→120℃→90℃, and the microwave auxiliary section has a microwave frequency of 2.45 GHz and a microwave radiation power density of less than or equal to 10 kW / m³.

8. The production line for preparing thermoplastic dry prepreg yarn according to claim 1, characterized in that, The cooling roller assembly includes at least two cooling rollers, the interior of which is filled with a 5-10°C circulating coolant, and the surface of the cooling rollers is provided with an array of micro-protrusions; the ring blowing device sprays nitrogen gas at a pressure of 0.3-0.6 MPa.

9. The production line for preparing thermoplastic dry prepreg yarn according to claim 1, characterized in that, The data acquisition component includes: A tension sensor is used to collect the current winding tension of the fiber to be processed in the winding area in real time. An infrared thickness gauge is used to collect the thickness value of the fiber to be processed before winding. An X-ray inspection instrument is used to collect surface defects of the fiber to be treated before winding.

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