Production line and method for preparing thermoplastic dry-process prepreg yarns

Abstract

The invention discloses a preparation production line and a preparation method of thermoplastic dry-process prepreg yarns. The production line comprises a fiber unwinding area, a fiber unfolding area, an infiltration area, a drying area, a cooling area and a winding area which are sequentially arranged, to-be-processed fibers bypass all creels of the rotary creel set, and the tension detector is used for obtaining the current unwinding tension of the to-be-processed fibers in real time; the fiber unfolding area is provided with a first yarn guide roller set and a static electricity eliminating device, and the to-be-processed fiber winds around the first yarn guide roller set after being wound out of the rotary creel set; the infiltration area is provided with a second yarn guide roller set and an impregnation tank containing water-based resin; the cooling area is provided with a fourth yarn guide roller set, a cooling roller set and an annular blowing device, and the winding area is provided with a fifth yarn guide roller set, a winding roller, a winding driving piece in transmission connection with the winding roller and a data acquisition assembly. And the preparation effect of the thermoplastic dry-process prepreg yarn is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of thermoplastic composite material prepreg preparation, and in particular to a production line and a method for preparing thermoplastic dry prepreg yarn based on high-performance fibers impregnated with aqueous polyurethane resin. Background Art

[0002] In the field of thermoplastic composite prepreg preparation, the traditional wet process uses organic solvents (such as acetone) to dilute the resin, resulting in 0.5-1.2% volatile organic compounds (VOC) remaining in the prepreg, which is highly polluting and will cause pore defects during composite molding. In addition, the traditional wet process uses melt impregnation or roll impregnation methods, using high-temperature and high-pressure equipment for preparation. However, the production line of the traditional wet process has the following problems:

[0003] The existing melt impregnation method requires high temperature and high pressure equipment, and the resin needs to be heated to 200-300 ° C, which can easily lead to oxidation damage to the interface of high-performance fibers (such as carbon fibers), resulting in a loss of tensile strength of 15-20%, and poor resin permeability.

[0004] The traditional roller impregnation method is prone to "racetrack effect" due to the high viscosity of the resin, and the resin content in the core of the fiber bundle is 40-60% lower than that on the surface;

[0005] The melt viscosity of thermoplastic resin is usually greater than 5000 Pa·s. The fiber width of existing technology is less than 120% of the original diameter, which makes it difficult to fully penetrate the resin.

[0006] The traditional process causes the fiber arrangement density deviation to be greater than 15% due to tension fluctuation (±5N), and the thickness tolerance of the final product reaches ±10%, resulting in poor process continuity and large quality fluctuations.

[0007] In summary, existing dry prepreg technology is mostly limited to thermosetting resin systems. The traditional wet impregnation process has technical defects such as solvent residue, high energy consumption and uneven resin distribution. The melt impregnation method requires high temperature and high pressure equipment, which can easily cause fiber damage and poor resin permeability. Summary of the Invention

[0008] To this end, an embodiment of the present invention provides a production line and a method for preparing thermoplastic dry prepreg yarn to solve at least one of the above technical problems.

[0009] In order to achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0010] The present invention 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 in sequence; wherein:

[0011] The fiber unwinding area is provided with a rotary creel group, an unwinding drive member connected to the active creel in the rotary creel group, and a tension detector; the fiber to be processed passes around each creel of the rotary creel group, and the tension detector is used to obtain the current unwinding tension of the fiber to be processed in real time;

[0012] The fiber spreading area is provided with a first guide roller group and an electrostatic eliminator. After the fiber to be processed is wound out from the rotary creel group, it passes around the first guide roller group.

[0013] The impregnation area is provided with a second guide roller group and an impregnation tank containing an aqueous resin. After the fiber to be treated is wound out from the first guide roller group, it passes around the second guide roller group and passes above the impregnation tank. A dipping roller is provided above the impregnation tank. A portion of the dipping roller is immersed in the dipping tank. As the dipping roller rotates, the aqueous resin in the dipping tank is applied to the surface of the fiber to be treated.

[0014] The drying area is provided with a third guide roller group, and the fibers to be processed are wound around the third guide roller group after being wound around the second guide roller group;

[0015] The cooling area is provided with a fourth yarn guide roller group, a cooling roller group and a ring blowing device. After the fiber to be treated is wound from the third yarn guide roller group, it passes through the rollers of the fourth yarn guide roller group and the rollers of the cooling roller group in sequence and is cooled by air through the ring blowing device.

[0016] The winding area is provided with a fifth guide roller group, a winding roller, a winding drive member connected to the winding roller, and a data acquisition component. After the fiber to be processed is wound from the fourth guide roller group, it passes around the fifth guide roller group and then winds onto the winding roller. The data acquisition component is used to collect status data of the fiber to be processed in real time during the winding process.

[0017] A controller is configured to receive the current unwinding tension detected by the tension detector and generate an unwinding adjustment instruction based on the relationship between the current unwinding tension and a pre-stored preset unwinding tension, wherein the unwinding adjustment instruction is configured to control the output speed of the unwinding drive member; the controller is further configured to receive status data detected by the data acquisition component and generate status adjustment instructions and / or quality monitoring results based on the status data.

[0018] In some embodiments, the unwinding drive is a servo motor;

[0019] The controller receives the current unwinding tension detected by the tension detector and calculates a floating value between the current unwinding tension and the unwinding tension at a previous moment;

[0020] When the floating value is greater than the maximum value of the preset tension floating range or less than the minimum value of the preset tension floating range, the controller generates an unwinding adjustment instruction, and the unwinding adjustment instruction is used to start the servo motor;

[0021] When the servo motor is in the starting state, if the current unwinding tension is greater than the maximum value of the preset tension floating 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 floating range, the servo motor is controlled to rotate reverse to rewind.

[0022] In some embodiments, the first guide roller set includes at least three guide rollers with different curvature radii, and the guide rollers are spatially staggered to form a three-dimensional fiber spreading channel; and / or,

[0023] The high-voltage electrostatic field generated by the static elimination device is an adjustable electrostatic field of 0.5-2.0 kV.

[0024] In some embodiments, the infiltration area is further provided with an ultrasonic assisted infiltration device, and the ultrasonic assisted infiltration device emits an ultrasonic wave which is a longitudinal vibration wave with a frequency of 28 kHz.

[0025] In some embodiments, a porous guide plate is provided in the dipping tank;

[0026] And / or, a temperature control device is provided outside the dipping tank; and / or,

[0027] A scraper is provided above the dipping tank, and a preset gap is formed between the scraper and the outer surface of the dipping roller.

[0028] In some embodiments, the fiber to be treated is divided into an infrared radiation section, a hot air convection section and a microwave assisted section in the drying area in sequence. The infrared radiation section is provided with an infrared radiation heater, the hot air convection section is provided with a hot air drying furnace, and the microwave assisted section is provided with a microwave dryer.

[0029] In some embodiments, the infrared radiation power density of the infrared radiation section is 3-5 W / cm 2 The wind speed of the hot air convection section is 0.8-1.5m / s, the temperature gradient is 80℃→120℃→90℃, the microwave frequency of the microwave auxiliary section is 2.45GHz, and the microwave radiation power density is less than or equal to 10kW / m 3 .

[0030] In some embodiments, the cooling roller group includes at least two cooling rollers, the interior of the cooling rollers is passed through with 5-10°C circulating coolant, and the surface of the cooling rollers is provided with a micro-bump array; the ring blowing device sprays nitrogen at a pressure of 0.3-0.6MPa.

[0031] In some embodiments, the data acquisition component includes:

[0032] A tension sensor, the tension sensor being used to collect in real time the current winding tension of the fiber to be processed in the winding area;

[0033] An infrared thickness gauge, which is used to collect the thickness of the fiber to be processed before winding;

[0034] An X-ray detector is used to detect surface defects of the fiber to be processed before winding.

[0035] The present invention also provides a method for preparing a thermoplastic dry prepreg yarn, comprising the following steps:

[0036] S1: The fiber to be processed is mounted on the rotary creel assembly, and the unwinding drive is started to unwind the fiber. During the unwinding process, the tension detector monitors the unwinding tension of the fiber in real time and transmits the data to the controller. The controller generates an unwinding adjustment instruction based on the tension fluctuation value and adjusts the speed and rotation direction of the unwinding drive to ensure that the fiber to be processed is unwound with a stable tension.

[0037] S2: After the fiber to be processed is wound from the unwinding area, it passes through the first guide roller group and is spread out in the three-dimensional fiber spreading channel formed by the first guide roller group. During the spreading process, the static eliminator is activated to generate a high-voltage static field to eliminate static electricity on the fiber surface.

[0038] S3: After being wound from the unwinding area, the fibers to be treated pass through the second guide roller assembly and enter the impregnation tank above where they are impregnated with the water-based resin. During the impregnation process, a porous guide plate guides the resin flow to ensure uniform impregnation of the fibers, and ultrasonic-assisted impregnation is activated. The impregnation temperature is 35-45°C, and the dynamic viscosity of the water-based polyurethane resin is 800-1200 mPa·s.

[0039] S4: After the treated fiber is wound out of the impregnation area, it enters the infrared radiation section, hot air convection section and microwave assisted section of the drying area in sequence. When entering the infrared radiation section, the infrared radiation heater is started to perform preliminary drying on the fiber. The infrared radiation power density is 3-5W / cm 2 When entering the hot air convection section, the hot air drying furnace is started. The wind speed of the hot air drying furnace is 0.8-1.5m / s, and the temperature gradient is 80℃→120℃→90℃ to further dry the fiber. When entering the microwave auxiliary section, the microwave dryer is started. The frequency of the microwave dryer is 2.45GHz and the power density is less than or equal to 10kW / m 3 , make sure the fibers are completely dry;

[0040] S5: After the treated fiber is wound out of the drying area, it passes through the first roller of the fourth guide roller group, the first roller of the cooling roller group, the second roller of the fourth guide roller group, the first roller of the cooling roller group and the third roller of the fourth guide roller group in sequence. The cooling roller circulates coolant at 5-10°C to reduce the fiber temperature, and the micro-convex array increases the cooling efficiency; the ring blowing device is started and nitrogen is sprayed at a pressure of 0.3-0.6MPa to cool the fiber with nitrogen, so that the treated fiber undergoes a rapid cooling process from 45°C to 25°C, with a cooling rate of more than 30°C / s;

[0041] S6: After the fiber to be processed is wound out of the cooling area, it passes through the fifth guide roller group and is wound onto the winding roller. The winding drive is started to evenly wind the fiber onto the winding roller. 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.

[0042] In one or more of the above specific embodiments, the preparation production line and preparation method provided by the present invention have at least the following technical effects:

[0043] 1. The present invention adopts a three-stage dehydration process with a water-based polyurethane resin and a 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 gradually increase the temperature to evaporate free water. Finally, the microwave-assisted section is used to directionally remove bound water, so that the final residual moisture content is less than 0.05%, completely eliminating the porosity problem caused by solvent volatilization.

[0044] 2. The present invention uses a low-temperature impregnation process of 35-45°C in the impregnation area (resin dynamic viscosity 800-1200mPa·s) combined with a double-helix cooling roller and nitrogen ring blowing in the cooling area to make the treated fiber undergo a rapid cooling process from 45°C to 25°C (cooling rate > 30°C / s), which significantly improves the carbon fiber strength retention rate;

[0045] 3. The present invention sets a porous guide plate in the impregnation tank to form a turbulent flow field (Reynolds number Re>4000), and cooperates with the 28kHz longitudinal vibration wave of the ultrasonic system to achieve a resin penetration depth reaching the single-filament level (SEM observation shows that the surface of each fiber is covered with a resin layer with a thickness of 2-3μm), and the interfacial shear strength (IFSS) is increased to above 45MPa;

[0046] 4. The present invention uses a dielectric barrier static elimination device in the fiber spreading area to apply a 0.5-2.0kV electrostatic field to form a uniform charge layer on the surface of the fiber bundle. Combined with the three-dimensional fiber spreading effect of the curved first guide roller group, the fiber width expansion rate is achieved by 300% (from the original width of 1K carbon fiber bundle 1.2mm to 3.6mm), the specific surface area is increased by 250%, and the resin penetration path is shortened to the micron level;

[0047] 5. The present invention improves the level of product automation and quality monitoring by controlling the tension fluctuation in the unwinding area and coordinating with the online monitoring system in the winding area. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments or the description of the prior art. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other implementation drawings based on the provided drawings without inventive effort.

[0049] The structures, proportions, sizes, etc. illustrated in this specification are intended only to complement the contents disclosed herein and to facilitate understanding and reading by persons familiar with the art. They are not intended to limit the conditions under which the present invention may be implemented and therefore have no substantive technical significance. Any structural modifications, changes in proportions, or adjustments in sizes, without affecting the efficacy and objectives of the present invention, shall still fall within the scope of the technical contents disclosed herein.

[0050] Figure 1 This is a schematic structural diagram of a production line for preparing thermoplastic dry prepreg yarn provided by the present invention;

[0051] Figure 2 This is a schematic structural diagram of the fiber unwinding area in the production line for preparing thermoplastic dry prepreg yarn provided by the present invention;

[0052] Figure 3 This is a schematic structural diagram of the fiber spreading area in the production line for preparing the thermoplastic dry prepreg provided by the present invention;

[0053] Figure 4 This is a schematic structural diagram of the impregnation area in the production line for preparing thermoplastic dry prepreg yarn provided by the present invention;

[0054] Figure 5 This is a schematic structural diagram of the drying area in the production line for preparing thermoplastic dry prepreg yarn provided by the present invention;

[0055] Figure 6 This is a schematic structural diagram of the cooling area in the production line for preparing thermoplastic dry prepreg yarn provided by the present invention;

[0056] Figure 7 This is a schematic structural diagram of the winding area in the production line for preparing thermoplastic dry prepreg yarn provided by the present invention;

[0057] Figure 8This is a SEM observation image of the resin coating thickness of the fiber to be treated processed by the preparation production line provided by the present invention;

[0058] Figure 9 This is an interface diagram of the experimental results of the interfacial shear strength of the fibers to be treated processed by the preparation production line provided by the present invention;

[0059] Figure 10 This is an interface diagram of the experimental results of the fiber width expansion rate of the fiber to be processed processed by the preparation production line provided by the present invention.

[0060] Description of reference numerals:

[0061] 100. Fiber to be treated;

[0062] 10. Fiber unwinding area;

[0063] 101. Rotary creel assembly; 102. Unwinding drive unit; 103. Photoelectric encoder;

[0064] 20. Fiber expansion area;

[0065] 201. First yarn guide roller group; 202. Static elimination device;

[0066] 30. Infiltration area;

[0067] 301, dipping tank; 302, porous guide plate; 303, temperature control device; 304, ultrasonic assisted infiltration device;

[0068] 40. Drying area;

[0069] 401, infrared radiation section; 402, hot air convection section; 403, microwave auxiliary section;

[0070] 50. Cooling area;

[0071] 501, fourth yarn guide roller group; 502, cooling roller group; 503, ring blowing device;

[0072] 60. Winding area;

[0073] 601, fifth yarn guide roller group; 602, winding roller; 603, winding drive member; 604, infrared thickness gauge; 605, X-ray detector. DETAILED DESCRIPTION

[0074] The following describes the implementation of the present invention using specific embodiments. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. Obviously, the embodiments described are only a portion of the present invention, not all of it. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are intended to fall within the scope of protection of the present invention.

[0075] In a specific embodiment, Figure 1 As shown, the production line for preparing thermoplastic dry prepreg yarn provided by the present invention 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 which are arranged in sequence.

[0076] Among them, such as Figure 2 As shown, the fiber unwinding area 10 is provided with a rotary creel group 101, an unwinding drive 102 connected to the active creel in the rotary creel group 101, and a tension detector; the fiber to be processed 100 passes around each creel of the rotary creel group 101, and the tension detector is used to obtain the current unwinding tension of the fiber to be processed 100 in real time.

[0077] In a specific usage 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 composed of an unwinding drive 102 and a tension detector to ensure that the fiber tension fluctuation is controlled within the range of ±1N. If the tension detector detects that the fiber tension value fluctuation is greater than the normal range, it will be fed back to the servo motor. When the tension is large, the servo motor will rotate forward quickly to achieve unwinding and stabilize the tension. When the tension value is low, the servo motor will reverse to achieve yarn winding and stabilize the tension value.

[0078] like Figure 3As shown, the fiber spreading area 20 is equipped with a first guide roller assembly 201 and an electrostatic eliminator 202. After being wound from the rotary creel assembly 101, the fiber 100 to be processed passes around the first guide roller assembly 201. Specifically, the fiber spreading area 20 is equipped with a curved array of first guide rollers 201 and a dielectric barrier discharge electrostatic eliminator 202. The electrostatic eliminator 202 is connected to the closest roller in the first guide roller assembly 201 via a mounting plate to reduce the impact of static electricity during the transfer of the carbon fiber tow. To ensure more uniform spreading of the carbon fiber tow during the spreading process, the guide roller assembly includes at least three sets of ceramic guide rollers with different curvature radii. For example, the ceramic rollers can have radii of 20 mm, 25 mm, and 30 mm, respectively. The ceramic guide rollers are spatially staggered to form a three-dimensional fiber spreading channel. Combined with the synergistic effect of an adjustable high-voltage electrostatic field of 0.5-2.0 kV, the fiber bundle width expansion rate reaches 150%-300%.

[0079] like Figure 4 As shown, the above-mentioned impregnation area 30 is provided with a second guide roller group and an impregnation tank 301 containing an aqueous resin. After the fiber 100 to be treated is wound out from the first guide roller group 201, it bypasses the second guide roller group and passes over the top of the impregnation tank 301. A dipping roller is provided above the dipping tank, and a part of the dipping roller is immersed in the dipping tank. As the dipping roller rotates, the aqueous resin in the dipping tank is applied to the surface of the fiber to be treated. A scraper is provided above the dipping tank, and there is a preset gap between the scraper and the outer surface of the dipping roller. Specifically, the infiltration area 30 includes an immersion tank 301 and an ultrasonic auxiliary system. A porous guide plate 302 is set in the immersion tank 301 to form a resin turbulent flow field. The tank body is equipped with a temperature control device 303 to maintain the resin temperature in the range of 35-45°C. 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.

[0080] 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. Because the impregnation roller may carry too much resin during the impregnation process, a scraper is provided to scrape off the excess resin, thereby ensuring more uniform fiber impregnation. It should be understood that the preset gap between the scraper and the impregnation roller is to ensure that the necessary thickness of resin is passed through, and this preset gap can be adjusted as needed.

[0081] The water-based resin can specifically be a water-based polyurethane resin with a solid content of 20%-28%. Alternatively, a water-based acrylate or polyester emulsion system can be used instead of polyurethane. By adjusting the type of emulsifier (such as non-ionic surfactant), a similar low-temperature wetting effect can be achieved while maintaining nano-scale dispersion characteristics. Alternatively, a thermoplastic elastomer (TPE) and a low-melting-point polyolefin blend system can be used to replace the water-based resin through a melt extrusion coating process. In this case, a higher-precision temperature control module (±1°C) is required.

[0082] like Figure 5 As shown, the drying area 40 is provided with a third guide roller group. The fiber 100 to be treated is wound around the third guide roller group after being wound from the second guide roller group. Specifically, the drying area 40 adopts a multi-stage gradient temperature control tunnel, which includes an infrared radiation section 401, a hot air convection section 402 and a microwave auxiliary section 403. The power density of the infrared section is 3-5W / cm 2 The hot air section has a wind speed of 0.8-1.5m / s and a temperature gradient of 80℃→120℃→90℃; the microwave section has a frequency of 2.45GHz and a power density of no more than 10kW / m 3 , achieving water evaporation rate>1.2kg / (m 2 ·h).

[0083] Specifically, the infrared radiation section is provided with an infrared radiation heater, the hot air convection section is provided with a hot air drying furnace, and the microwave auxiliary section is provided with a microwave dryer; the infrared radiation section is provided with an infrared radiation heater, which directly heats the surface of the material by emitting infrared rays of a specific wavelength to achieve rapid heating.

[0084] The hot air convection section device is equipped with a hot air drying furnace, which can be used to dry the impregnated carbon fiber by transferring heat to the material through hot air convection, removing excess solvent and water, and preliminarily solidifying the resin.

[0085] The microwave-assisted section is equipped with a microwave dryer, which allows microwave energy to penetrate the interior of the material to achieve efficient heating at the molecular level, reducing drying time and improving curing quality.

[0086] like Figure 6As shown, the cooling area 50 is provided with a fourth guide roller group 501, a cooling roller group 502 and a ring blowing device 503. After the fiber 100 to be treated is wound from the third guide roller group, it passes around the rollers of the fourth guide roller group 501 and the rollers of the cooling roller group 502 in sequence, and is air-cooled by the ring blowing device 503. Specifically, the cooling area 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. A 5-10°C circulating coolant is passed through the interior of the cooling rollers. An array of micro-bumps is provided on the surface to increase the heat exchange area. The ring blowing device 503 sprays nitrogen at a pressure of 0.3-0.6 MPa, so that the surface temperature of the prepreg drops sharply from 80°C to 25±3°C within 0.5-2 seconds.

[0087] Furthermore, if Figure 7 As shown, the winding area 60 is provided with a fifth guide roller group 601, a winding roller 602, a winding drive member 603 connected to the winding roller 602, and a data acquisition component. After the fiber 100 to be processed is wound off from the fourth guide roller group 501, it passes around the fifth guide roller group 601 and then is wound onto the winding roller 602; the data acquisition component is used to collect the status data of the fiber to be processed 100 in real time during the winding process.

[0088] Specifically, the winding area 60 includes a constant linear speed winding mechanism and an online quality monitoring system. The winding mechanism adopts a differential planetary gear transmission and cooperates with a tension sensor to achieve 0.01N·m level torque control. This online detection system uses infrared and X-rays to check product quality at the same time. Infrared rays are responsible for real-time measurement of material thickness, and X-rays are like CT scans of products, which can detect internal defects such as bubbles and cracks. The two sets of detection data will be merged and analyzed in real time. If the thickness deviation exceeds 5% or a defect the size of a sesame seed (0.005 cubic millimeters or more) is found, an alarm will be immediately issued, and a detection report containing the location and severity of the problem will be automatically generated. The system has a built-in fault emergency mode. Even if one detector has a problem, the other can continue to work to ensure that the production line does not stop. The detection accuracy reaches 1 / 60 of the thickness of a hair. The detection results are directly connected to the factory management system to help quickly control product quality.

[0089] The controller is used to receive the current unwinding tension detected by the tension detector, and generate an unwinding adjustment instruction based on the relationship between the current unwinding tension and the pre-stored preset unwinding tension, and the unwinding adjustment instruction 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 instruction and / or generate a quality monitoring result based on the status data.

[0090] In a specific usage scenario, the controller provided by the present invention is specifically a PLC control system, which drives the roller to rotate through an electric motor. During the operation of the winding equipment, the tension detection device of the winding equipment feeds back the detected prepreg yarn tension value to the PLC system. In the human-computer interaction interface, the prepreg yarn tension range (15-20N) is pre-set, 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, and the tension adjustment mechanism motor will be started, and the tension will be adjusted by forward and reverse rotation to keep the prepreg yarn tension within the predetermined range.

[0091] During operation, the yarn to be processed is unwound from the rotary yarn frame group 101 in the yarn unwinding area, and the unwinding drive 102 adjusts the unwinding speed according to the tension detected by the tension detector; the yarn enters the yarn unwinding area, is unwound by the first guide roller group 201, and the static electricity is eliminated by the static eliminator 202; the yarn enters the impregnation area 30, bypasses the second guide roller group and passes above the impregnation tank 301, and is impregnated with thermoplastic resin; after impregnation, the yarn enters the drying area 40, passes through the infrared radiation section 401, the hot air convection section 402 and the microwave assisted section 403 in sequence through the third guide roller group for drying; the dried yarn enters the cooling area 50, bypasses the fourth 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, bypasses the fifth guide roller group 601 and is wound onto the winding roller 602, and the data acquisition component collects status data in real time.

[0092] This production line enables continuous yarn processing and improves production efficiency. Through tension detection and adjustment, the yarn tension is kept stable during the unwinding and rewinding process, and the static elimination device 202 effectively prevents fiber entanglement caused by static electricity during the unwinding process. The multi-stage drying and cooling process ensures that the yarn can be quickly solidified after impregnation while avoiding thermal damage. The data acquisition component monitors the yarn status in real time, making it easy to detect and deal with quality problems in a timely manner.

[0093] 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 floating value between the current unwinding tension and the unwinding tension at the previous moment; when the floating value is greater than the maximum value of the preset tension floating range or less than the minimum value of the preset tension floating range, the controller generates an unwinding adjustment instruction, and the unwinding adjustment instruction is used to start the servo motor; when the servo motor is in the starting state, if the current unwinding tension is greater than the maximum value of the preset tension floating 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 floating range, the servo motor is controlled to reverse and rewind.

[0094] Servo motors can precisely control unwinding speed, with fast response and high adjustment accuracy. Real-time monitoring and adjustment of floating values ​​further improves yarn tension stability. Variable frequency motors can also be used instead of servo motors, reducing costs while maintaining a certain level of adjustment performance.

[0095] Alternatively, pneumatic closed-loop control or AI predictive control can be used. Pneumatic closed-loop control replaces the magnetic powder brake with a pneumatic servo valve (response time <10ms) and combines it with a pressure sensor to achieve dynamic tension compensation, further reducing the fluctuation range to ±0.3N. AI predictive control integrates machine learning algorithms to analyze the yarn's trajectory, predict tension trends, and adjust the unwinding speed in advance, reducing the mechanical lag of the floating roller.

[0096] In some embodiments, the first yarn guide roller assembly 201 includes at least three guide rollers with different curvature radii, arranged in a staggered pattern to form a three-dimensional fiber spreading channel. The static eliminator 202 generates an adjustable high-voltage electrostatic field between 0.5 and 2.0 kV. This three-dimensional fiber spreading channel effectively spreads the yarn and reduces fiber entanglement. The adjustable electrostatic field can be flexibly adjusted based on the static charge level of the yarn, enhancing the static elimination effect.

[0097] It should be understood that in actual use, the number and complexity of the yarn guide roller groups can be increased to further optimize the fiber spreading effect, and an ion blower can be used instead of a high-voltage electrostatic field to provide a more uniform static elimination effect. Mechanical vibration fiber spreading or airflow-assisted fiber spreading can also be used; when mechanical vibration fiber spreading is used, a piezoelectric ceramic vibrating plate (frequency 1-5kHz) is embedded in the first yarn guide roller group 201, and high-frequency micro-vibration is used to assist fiber spreading, replacing the static elimination device 202, and the fiber spreading width expansion rate can reach 200%. When airflow-assisted fiber spreading is used, a high-pressure airflow nozzle (0.2-0.5MPa) is added to the gap between the yarn guide rollers, and the laminar gas shear force is used to disperse the fiber bundle, which is suitable for the uniform spreading of high modulus fibers (such as carbon fibers).

[0098] In some embodiments, the impregnation area 30 is further provided with an ultrasonic-assisted impregnation device 304. The ultrasonic-assisted impregnation device 304 emits ultrasonic 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 by increasing the number of ultrasonic devices to improve impregnation efficiency.

[0099] The impregnation tank 301 is provided with a porous guide plate 302, and a temperature control device 303 is provided outside the impregnation tank 301. The porous guide plate 302 ensures more uniform resin flow, improving impregnation quality, while the temperature control device 303 precisely controls the temperature within the impregnation tank 301 to ensure stable resin performance. It should be understood that using guide plates of different shapes and apertures can further optimize resin flow, enhance the insulation of the impregnation tank 301, and reduce heat loss.

[0100] Alternatively, high-pressure jet impregnation or vacuum-assisted impregnation can be used. In high-pressure jet impregnation, a multi-hole nozzle array (aperture 50-100 μm) vertically sprays atomized resin droplets (particle size <10 μm) onto the fiber bundle, replacing the impregnation tank 301. This improves resin penetration efficiency by 30%. In vacuum-assisted impregnation, a negative pressure of -0.08 to -0.1 MPa is applied within a sealed cavity, prompting the resin to quickly fill the interfiber gaps. This eliminates the need for an ultrasonic system and reduces resin viscosity requirements.

[0101] In some embodiments, the fiber to be treated is 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 provided with an infrared radiation heater, the hot air convection section is provided with a hot air drying furnace, and the microwave-assisted section is provided with a microwave dryer. The infrared radiation power density of the infrared radiation section 401 is 3-5 W / cm 2 The wind speed of the hot air convection section 402 is 0.8-1.5m / s, the temperature gradient is 80℃→120℃→90℃, the microwave frequency of the microwave auxiliary section 403 is 2.45GHz, and the microwave radiation power density is less than or equal to 10kW / m 3 .

[0102] Alternatively, radio frequency drying or pulsed hot air drying can be used. In radio frequency drying, a 13.56 MHz radio frequency generator generates an alternating electric field, causing frictional heating of the resin's polar molecules. This replaces infrared radiation in Section 401, reducing energy consumption by 40% and improving drying uniformity. Pulsed hot air drying uses intermittent high-speed airflow (2-3 m / s, 0.5-2 Hz frequency) to impact the prepreg surface, shortening water evaporation time and making it suitable for high-solids resin systems.

[0103] In some embodiments, the cooling roller group 502 includes at least two cooling rollers, the interior of each cooling roller is passed through a 5-10°C circulating coolant, and the surface of each cooling roller is provided with a micro-bump array; the ring blowing device 503 sprays nitrogen at a pressure of 0.3-0.6 MPa. In addition, liquid nitrogen spray quenching or contact cooling plates can also be used; wherein, when 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 roller to cool the prepreg to below 20°C within 0.1-0.3 seconds, thereby inhibiting the separation of resin crystal phases; when contact cooling plates are used, a microchannel cooling copper plate (thermal conductivity coefficient > 400 W / m·K) is used to directly press the prepreg surface, replacing the gas ring blowing device 503, and the cooling efficiency is increased by 50%.

[0104] 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 collect 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 collect the thickness value of the fiber to be processed 100 before winding, and the X-ray detector 605 is used to collect surface defects of the fiber to be processed 100 before winding.

[0105] In addition, magnetic levitation synchronous winding or optical in-situ monitoring can also be used; when magnetic levitation synchronous winding is used, a contactless magnetic coupler replaces the planetary gear transmission to achieve torque control with zero mechanical wear (accuracy ±0.005N·m); when using optical in-situ monitoring, an integrated Raman spectrometer analyzes the resin curing degree in real time, replacing the X-ray detector 605, avoiding radiation contamination and achieving a resolution of 1μm.

[0106] The present invention also provides a method for preparing a thermoplastic dry prepreg yarn, comprising the following steps:

[0107] S1: The fiber to be processed 100 is mounted on the rotary creel assembly 101, and the unwinding drive 102 is started to start the fiber unwinding. 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 a controller. The controller generates an unwinding adjustment instruction based on the tension fluctuation value and adjusts the speed and rotation direction of the unwinding drive 102 to ensure that the fiber to be processed 100 is unwound with a stable tension.

[0108] S2: After being wound from the unwinding area, the fiber to be processed 100 passes through the first guide roller group 201 and is spread out in the three-dimensional fiber spreading channel formed by the first guide roller group 201. During the spreading process, the static eliminator 202 is activated to generate a high-voltage electrostatic field to eliminate static electricity on the fiber surface.

[0109] S3: After being wound out of the unwinding area, the fiber 100 to be treated passes through the second guide roller assembly and enters the upper portion of the impregnation tank 301, where it is impregnated with the aqueous resin in the impregnation tank 301. During the impregnation process, the porous guide plate 302 guides the resin flow to ensure uniform impregnation of the fiber, and ultrasonic-assisted impregnation is activated. The impregnation temperature is 35-45°C, and the dynamic viscosity of the aqueous polyurethane resin is 800-1200 mPa·s.

[0110] S4: After the fiber 100 is wound out of the impregnation area 30, it enters the infrared radiation section 401, the hot air convection section 402, and the microwave-assisted section 403 of the drying area 40 in sequence. When entering the infrared radiation section 401, the infrared radiation heater is started to perform preliminary drying on the fiber. The infrared radiation power density is 3-5 W / cm 2 When entering the hot air convection section 402, the hot air drying furnace is started. The wind speed of the hot air drying furnace is 0.8-1.5m / s, and the temperature gradient is 80℃→120℃→90℃ to further dry the fiber. When entering the microwave auxiliary section 403, the microwave dryer is started. The frequency of the microwave dryer is 2.45GHz and the power density is less than or equal to 10kW / m 3 , make sure the fibers are completely dry;

[0111] S5: After the fiber 100 to be treated is wound out of the drying area 40, it passes through the first roller of the fourth guide roller group 501, the first roller of the cooling roller group 502, the second roller of the fourth guide roller group 501, the first roller of the cooling roller group 502 and the third roller of the fourth guide roller group 501 in sequence. The cooling roller circulates a 5-10°C circulating coolant to reduce the fiber temperature, and the micro-convex array increases the cooling efficiency. The ring blowing device 503 is started to spray nitrogen at a pressure of 0.3-0.6 MPa to cool the fiber with nitrogen, so that the fiber 100 to be treated undergoes a rapid cooling process from 45°C to 25°C, with a cooling rate of >30°C / s.

[0112] S6: After the fiber 100 to be processed is wound out from the cooling area 50, it passes through the fifth guide roller group 601 and is wound onto the winding roller 602. The winding drive 603 is started to evenly wind the fiber onto the winding 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.

[0113] In one or more of the above specific embodiments, the preparation production line and preparation method provided by the present invention have at least the following technical effects:

[0114] 1. The present invention utilizes a three-stage dehydration process using a water-based polyurethane resin in conjunction with a drying zone 40. Infrared radiation section 401 is used to rapidly break down the surface hydration layer. Hot air convection section 402 is then used to gradually increase the temperature to evaporate free water. Finally, microwave-assisted section 403 is used to directionally remove bound water, resulting in a final residual moisture content of less than 0.05%, completely eliminating the porosity problem caused by solvent volatilization.

[0115] 2. The present invention uses low-temperature impregnation at 35-45°C in the impregnation area 30 (resin dynamic viscosity 800-1200 mPa·s) combined with double-helix cooling rollers and nitrogen ring blowing in the cooling area 50 to cause the treated fiber 100 to undergo a rapid cooling process from 45°C to 25°C (cooling rate > 30°C / s), thereby significantly improving the carbon fiber strength retention rate.

[0116] 3. The present invention sets a porous guide plate 302 in the infiltration tank to form a turbulent field (Reynolds number Re>4000), and cooperates with the 28kHz longitudinal vibration wave of the ultrasonic system to make the resin penetration depth reach the single-filament level (such as Figure 8 The SEM observation shows that each fiber surface is covered with a resin layer with a thickness of 2-3 μm). Figure 9 As shown, the interfacial shear strength (IFSS) is increased to above 45 MPa;

[0117] 4. The present invention adopts a dielectric barrier static elimination device 202 in the fiber spreading area 20, applies a 0.5-2.0kV electrostatic field, forms a uniform charge layer on the surface of the fiber bundle, and combines the three-dimensional fiber spreading effect of the first yarn guide roller group 201 in the form of a curved surface to achieve a fiber width expansion rate of 300% (such as Figure 10 As shown, the original width of the 1K carbon fiber bundle is expanded from 1.2mm to 3.6mm), the specific surface area is increased by 250%, and the resin penetration path is shortened to the micron level;

[0118] 5. The present invention improves the level of product automation and quality monitoring by controlling the tension fluctuation in the unwinding area and coordinating with the online monitoring system of the winding area 60.

[0119] The above specific implementation methods further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific implementation methods of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent replacements, improvements, etc. made on the basis of the technical solutions of the present invention should be included in the scope of protection of the present invention.

Claims

1. A production line for preparing thermoplastic dry prepreg yarn, characterized in that: It includes a fiber unwinding area, a fiber spreading area, a soaking area, a drying area, a cooling area and a winding area arranged in sequence; wherein: The fiber unwinding area is provided with a rotary creel group, an unwinding drive member connected to the active creel in the rotary creel group, and a tension detector; the fiber to be processed passes around each creel of the rotary creel group, and the tension detector is used to obtain the current unwinding tension of the fiber to be processed in real time; The fiber spreading area is provided with a first guide roller group and an electrostatic eliminator. After the fiber to be processed is wound out from the rotary creel group, it passes around the first guide roller group. The impregnation area is provided with a second guide roller group and an impregnation tank containing an aqueous resin. After the fiber to be treated is wound out from the first guide roller group, it passes around the second guide roller group and passes above the impregnation tank. A dipping roller is provided above the impregnation tank. A portion of the dipping roller is immersed in the dipping tank. As the dipping roller rotates, the aqueous resin in the dipping tank is applied to the surface of the fiber to be treated. The drying area is provided with a third guide roller group, and the fibers to be processed are wound around the third guide roller group after being wound around the second guide roller group; The cooling area is provided with a fourth yarn guide roller group, a cooling roller group and a ring blowing device. After the fiber to be treated is wound from the third yarn guide roller group, it passes through the rollers of the fourth yarn guide roller group and the rollers of the cooling roller group in sequence and is cooled by air through the ring blowing device. The winding area is provided with a fifth guide roller group, a winding roller, a winding drive member connected to the winding roller, and a data acquisition component. After the fiber to be processed is wound from the fourth guide roller group, it passes around the fifth guide roller group and then winds onto the winding roller. The data acquisition component is used to collect status data of the fiber to be processed in real time during the winding process. A controller is configured to receive the current unwinding tension detected by the tension detector and generate an unwinding adjustment instruction based on the relationship between the current unwinding tension and a pre-stored preset unwinding tension, wherein the unwinding adjustment instruction is configured to control the output speed of the unwinding drive member; the controller is further configured to receive status data detected by the data acquisition component and generate status adjustment instructions and / or quality monitoring results based on the status data.

2. The production line for preparing thermoplastic dry prepreg according to claim 1, characterized in that: The unwinding drive member is a servo motor; The controller receives the current unwinding tension detected by the tension detector and calculates a floating value between the current unwinding tension and the unwinding tension at a previous moment; When the floating value is greater than the maximum value of the preset tension floating range or less than the minimum value of the preset tension floating range, the controller generates an unwinding adjustment instruction, and the unwinding adjustment instruction is used to start the servo motor; When the servo motor is in the starting state, if the current unwinding tension is greater than the maximum value of the preset tension floating 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 floating range, the servo motor is controlled to rotate reverse to rewind.

3. The production line for preparing thermoplastic dry prepreg according to claim 1, characterized in that: The first guide roller set includes at least three guide rollers with different curvature radii, and the guide rollers are spatially staggered to form a three-dimensional fiber spreading channel; and / or, The high-voltage electrostatic field generated by the static elimination device is an adjustable electrostatic field of 0.5-2.0 kV.

4. The production line for preparing thermoplastic dry prepreg according to claim 1, characterized in that: The infiltration area is further provided with an ultrasonic assisted infiltration device, and the ultrasonic assisted infiltration device emits an ultrasonic wave which is a longitudinal vibration wave with a frequency of 28 kHz.

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

6. The production line for preparing thermoplastic dry prepreg according to claim 1, characterized in that: The fiber to be treated is 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 provided with an infrared radiation heater, the hot air convection section is provided with a hot air drying furnace, and the microwave assisted section is provided with a microwave dryer.

7. The production line for preparing thermoplastic dry prepreg according to claim 6, characterized in that: The infrared radiation power density of the infrared radiation section is 3-5W / cm 2 The wind speed of the hot air convection section is 0.8-1.5m / s, the temperature gradient is 80℃→120℃→90℃, the microwave frequency of the microwave auxiliary section is 2.45GHz, and the microwave radiation power density is less than or equal to 10kW / m 3 .

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

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

10. A method for preparing a thermoplastic dry prepreg, characterized in that: The following steps are involved: S1: The fiber to be processed is mounted on the rotary creel assembly, the unwinding drive is started, and the fiber begins to unwind; During the unwinding process, the tension detector monitors the unwinding tension of the fiber in real time and transmits the data to the controller. The controller generates an unwinding adjustment instruction based on the tension fluctuation value and adjusts the speed and direction of the unwinding drive to ensure that the fiber to be processed is unwound with a stable tension. S2: After the fiber to be processed is wound from the unwinding area, it passes through the first guide roller group and is spread out in the three-dimensional fiber spreading channel formed by the first guide roller group. During the spreading process, the static eliminator is activated to generate a high-voltage static field to eliminate static electricity on the fiber surface. S3: After being wound from the unwinding area, the fibers to be treated pass through the second guide roller assembly and enter the impregnation tank above where they are impregnated with the water-based resin. During the impregnation process, a porous guide plate guides the resin flow to ensure uniform impregnation of the fibers, and ultrasonic-assisted impregnation is activated. The impregnation temperature is 35-45°C, and the dynamic viscosity of the water-based polyurethane resin is 800-1200 mPa·s. S4: After the fiber to be treated comes out of the impregnation area, it enters the infrared radiation section, hot air convection section and microwave assisted section of the drying area in sequence; when entering the infrared radiation section, the infrared radiation heater is started to preliminarily dry the fiber, and the infrared radiation power density is 3-5W / cm2; when entering the hot air convection section, the hot air drying furnace is started, the wind speed of the hot air drying furnace is 0.8-1.5m / s, and the temperature gradient is 80℃→120℃→90℃, to further dry the fiber; when entering the microwave assisted section, the microwave dryer is started, the frequency of the microwave dryer is 2.45GHz, and the power density is less than or equal to 10kW / m 3 , make sure the fibers are completely dry; S5: After the treated fiber is wound out of the drying area, it passes through the first roller of the fourth guide roller group, the first roller of the cooling roller group, the second roller of the fourth guide roller group, the first roller of the cooling roller group and the third roller of the fourth guide roller group in sequence. The cooling roller circulates coolant at 5-10°C to reduce the fiber temperature, and the micro-convex array increases the cooling efficiency; the ring blowing device is started and nitrogen is sprayed at a pressure of 0.3-0.6MPa to cool the fiber with nitrogen, so that the treated fiber undergoes a rapid cooling process from 45°C to 25°C, with a cooling rate of more than 30°C / s; S6: After the fiber to be processed is wound out of the cooling area, it passes through the fifth guide roller group and is wound onto the winding roller. The winding drive is started to evenly wind the fiber onto the winding roller. 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.

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