Apparatus and method for vacuum assisted pultrusion of thermoplastic composite profiles

Abstract

The application provides a device and method for vacuum-assisted pultrusion of thermoplastic composite rods, and belongs to the field of civil engineering. The device solves the problem of bubbles generated by melt flow of thermoplastic resin, which reduces the forming quality of the thermoplastic composite rod. The device comprises a preheating module for preheating a thermoplastic prepreg tape, a heating module, a cooling module and a vacuum pumping device. The heating module comprises a first heating cavity, a vacuum cavity and a second heating cavity connected in sequence. The vacuum cavity is connected with the vacuum pumping device through a vacuum pumping port. The vacuum cavity adopts a gradient vacuum pumping design. Second heating components are arranged in the first heating cavity, the vacuum cavity and the second heating cavity. The cooling module is connected with the second heating cavity and used for cooling a thermoplastic composite rod product. Conical constraint components are arranged in the first heating cavity, the second heating cavity and the cooling module. The conical constraint components are used for narrowing the transmission path of the thermoplastic prepreg tape in the corresponding module. The device is mainly used for forming the thermoplastic composite rod.

Description

Technical Field

[0001] This invention belongs to the field of civil engineering, and in particular relates to an apparatus and method for vacuum-assisted pultrusion molding of thermoplastic composite reinforcement. Background Technology

[0002] With the ongoing development of major national projects such as cross-sea bridges, high-altitude and cold-weather railways, and port infrastructure, the complex service environments place increasingly stringent demands on the performance and quality of civil engineering structures. In harsh environments, traditional reinforced concrete buildings are prone to degradation in mechanical properties, impermeability, and corrosion resistance due to factors such as steel corrosion, thus reducing the structure's service life. Continuous fiber-reinforced composite materials, composed of a resin matrix and reinforcing fibers, possess excellent properties such as lightweight, high strength, and corrosion resistance. Replacing steel bars in concrete structures can effectively solve problems such as mechanical property degradation and reduced durability caused by steel corrosion.

[0003] Currently, continuous fiber-reinforced composite reinforcement bars are mainly formed through pultrusion. Among them, thermosetting composite reinforcement bars are widely used both domestically and internationally due to their advantages such as low resin viscosity, low molding temperature, wide processing range, and stable processing performance. However, thermosetting resins have many drawbacks, such as poor toughness, poor impact resistance, and non-recyclability. In contrast, thermoplastic resins have excellent toughness and do not produce harmful gases during fiber impregnation. Using them as the matrix of composite reinforcement bars can fully utilize their excellent impact resistance, high specific strength, and specific stiffness. Compared with thermosetting composite reinforcement bars, they have significant advantages such as bendability, recyclability, and environmental friendliness. However, most thermoplastic resins have high viscosity, making it difficult to impregnate continuous fibers, especially within fiber bundles, in the molten state. Using thermoplastic prepreg tape for secondary molding has become one of the effective ways to solve the fiber impregnation problem of fiber-reinforced thermoplastic resin-based composite reinforcement bars.

[0004] However, during the melt impregnation process of thermoplastic prepreg tape, the flow of molten thermoplastic resin generates air bubbles, resulting in large pores inside and on the surface of the thermoplastic prepreg tape when the resin impregnates the fibers. These internal defects limit the molding quality of the thermoplastic composite reinforcement. To address these issues, there is an urgent need for a molding device and method for continuous fiber reinforced thermoplastic composite reinforcement that is highly efficient, easy to operate, and widely applicable. Summary of the Invention

[0005] In view of this, the present invention aims to provide an apparatus and method for vacuum-assisted pultrusion molding of thermoplastic composite ribs, so as to solve the problem that the generation of bubbles in the melt flow of thermoplastic resin reduces the molding quality of thermoplastic composite ribs.

[0006] To achieve the above objectives, according to one aspect of the present invention, an apparatus for vacuum-assisted pultrusion molding of thermoplastic composite reinforcement is provided, comprising:

[0007] The preheating module is used to preheat the thermoplastic prepreg tape;

[0008] The heating module includes a first heating chamber, a vacuum chamber, and a tail heating chamber connected in sequence. The vacuum chamber is connected to a vacuum pumping device through a vacuum pumping port. A second heating component is provided in each of the first heating chamber, the vacuum chamber, and the tail heating chamber.

[0009] The cooling module, connected to the tail heating chamber, is used to cool the thermoplastic composite rib product. The first heating chamber, the tail heating chamber, and the cooling module are all equipped with conical constraint components, which are used to narrow the transmission path of the thermoplastic prepreg tape in the corresponding module.

[0010] Furthermore, the preheating module includes a yarn guide plate, guide rollers, a first heating component, a first preheating chamber, a last preheating chamber, and temperature sensors. The second end of the first preheating chamber is connected to the first end of the last preheating chamber. Both the first end of the first preheating chamber and the second end of the last preheating chamber are provided with yarn guide plates. The yarn guide plates are used to guide the yarn into or out of the corresponding preheating chamber. The first heating component is arranged along the pultrusion direction of the thermoplastic prepreg tape in both the first and last preheating chambers. Multiple temperature sensors are arranged at intervals on the side wall of the first preheating chamber along the pultrusion direction of the thermoplastic prepreg tape. Multiple guide rollers are provided and distributed in a dot matrix pattern in the first preheating chamber. The axial direction of each guide roller is perpendicular to the pultrusion direction of the thermoplastic prepreg tape.

[0011] Furthermore, multiple thermoplastic prepreg tape inlet holes are provided through the first end wall of the first preheating chamber, and all of the thermoplastic prepreg tape inlet holes correspond to the corresponding holes on the yarn guide plate.

[0012] Furthermore, multiple thermoplastic prepreg tape bundle holes are provided through the second end wall of the tail preheating cavity, and all of the thermoplastic prepreg tape bundle holes correspond to the corresponding holes on the yarn guide plate.

[0013] Furthermore, within the vacuum chamber of the heating module, along the pultrusion direction of the thermoplastic prepreg tape, the air pressure decreases gradually from both sides towards the center, and the channels of the vacuum extraction port are distributed in a funnel shape. During the vacuum extraction process, the pressure difference causes the thermoplastic resin to easily flow towards the vacuum extraction port and accumulate, affecting the uniform impregnation of the fibers. Therefore, a gradient vacuum extraction pressure scheme is proposed. On the one hand, the vacuum extraction device removes air bubbles generated by the enclosed air inside and between the thermoplastic prepreg tapes during the melt impregnation process. On the other hand, by guiding the thermoplastic resin to the area with lower air pressure, it promotes the full impregnation of the fibers. At the same time, the thermoplastic resin flows away from the conical constraint component, avoiding the "scraping" phenomenon on the surface of the thermoplastic composite material.

[0014] Furthermore, the vacuum chamber is provided with multiple sets of vacuum openings spaced apart along the pultrusion direction of the thermoplastic prepreg tape. Each set of vacuum openings contains two vacuum extraction ports arranged symmetrically on both sides relative to the thermoplastic prepreg tape, and each vacuum extraction port is provided with a corresponding vacuum extraction device.

[0015] Furthermore, the air pressure at the two vacuum evacuation ports within each set of vacuum openings is the same.

[0016] Furthermore, the tapered constraint assembly is a channel with a pore size that gradually decreases along the direction of movement of the thermoplastic prepreg tape.

[0017] Furthermore, the device also includes a traction device, the traction end of which is connected to the thermoplastic prepreg tape for traction of the thermoplastic prepreg tape through the preheating module, heating module and cooling module in sequence.

[0018] According to another aspect of the present invention, a method for using the above-described vacuum-assisted pultrusion molding apparatus for thermoplastic composite reinforcing bars is provided, comprising the following steps: after installing and fixing each module and the vacuum pumping device, starting the first heating component and the second heating component, and waiting for the preheating module and the heating module to stabilize at temperature; passing a thermoplastic prepreg strip of a certain cross section sequentially through the preheating module, the heating module and the cooling module and connecting it to the traction end of the traction device, starting the traction device, and adjusting the temperature of the preheating module and the heating module until the thermoplastic prepreg strip melts and is impregnated stably; starting all the vacuum pumping devices and adjusting the air pressure value corresponding to each vacuum pumping device according to the gradient, and using vacuum assistance to pultrude the thermoplastic prepreg strip.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] 1. This device utilizes a two-stage molding process with thermoplastic prepreg tape. During the melt impregnation process of the thermoplastic prepreg tape, a vacuum is created. The pressure difference between the cavity and the inside of the thermoplastic prepreg tape removes air bubbles generated by enclosed air within the tape and between the tapes during melt impregnation. This overcomes internal defects in the reinforcing material, such as bubbles and pores, caused by the high viscosity of thermoplastic resin and the difficulty in uniformly impregnating fibers. A gradient vacuum design guides the molten thermoplastic resin to a lower pressure area, promoting thorough impregnation of the fibers. The resulting thermoplastic composite reinforcing material exhibits low porosity and high fiber impregnation, meeting the performance requirements for high fiber content and large diameter thermoplastic composite reinforcing materials.

[0021] 2. This device adopts a semi-enclosed impregnation structure, which closely integrates the impregnation and molding processes, effectively reducing heat loss during heating and resulting in high molding efficiency. At the same time, the conical constraint component makes the impregnation and molding processes of the thermoplastic prepreg tape more closely integrated, allowing the resin to more easily and fully wet the fiber, reducing the possibility of bubbles and internal defects, and further improving the molding quality. Attached Figure Description

[0022] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0023] Figure 1 This is a three-dimensional structural schematic diagram of the device for vacuum-assisted pultrusion molding of thermoplastic composite material ribs according to the present invention;

[0024] Figure 2 This is a three-dimensional structural diagram of the preheating module described in this invention;

[0025] Figure 3 This is a cross-sectional view of the preheating module described in this invention;

[0026] Figure 4 This is a three-dimensional structural diagram of the heating module described in this invention;

[0027] Figure 5 This is a cross-sectional view of the heating module described in this invention;

[0028] Figure 6 This is a front view of the heating module described in this invention;

[0029] Figure 7 This is a cross-sectional view of the cooling module described in this invention.

[0030] Preheating module 1; yarn guide plate 101; top cover 102; guide roller 103; thermoplastic prepreg tape inlet hole 104; heating tube 105; thermoplastic prepreg tape bundle hole 106; first preheating chamber 107; last preheating chamber 108; temperature sensor 109; heating module 2; first heating chamber 201; heating rod 202; vacuum chamber 203; vacuum chamber processing channel 204; sealant 205; vacuum extraction pipe 206; pressure gauge 207; vacuum extraction device 208; vacuum extraction port 209; last heating chamber 210; cooling module 3; cooling chamber 301; traction device 4; conical constraint assembly 5. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other, and the described embodiments are only some embodiments of the present invention, not all embodiments.

[0032] It should be noted that the descriptions of "left," "right," "left side," "right side," "upper part," "lower part," "top," and "bottom" in this invention are defined based on the orientation or positional relationships shown in the accompanying drawings. They are merely for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the described structure must be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0033] In the description of this invention, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. Specific implementation method one:

[0035] In this embodiment, the object being processed is a continuous glass fiber reinforced polypropylene bar with a diameter of 20 mm.

[0036] Referring to the accompanying drawings, this embodiment of the invention provides an apparatus for vacuum-assisted pultrusion molding of thermoplastic composite reinforcement bars, characterized in that it comprises:

[0037] Preheating module 1 is used to preheat the thermoplastic prepreg tape. During preheating, the preheating temperature of preheating module 1 is 140-240℃, and the preheating time is 5-20 minutes. By setting these parameters, pultrusion molding of the processed object can be completed while ensuring sufficient power consumption.

[0038] Heating module 2 includes a first heating chamber 201, a vacuum chamber 203, and a tail heating chamber 210 connected in sequence. The vacuum chamber 203 is connected to a vacuum pumping device 208. Second heating components are installed in each of the first heating chamber 201, vacuum chamber 203, and tail heating chamber 210. The heating temperature of heating module 2 during normal operation is 200-300℃. By reasonably setting the length of each section, and coordinating with appropriate preheating and heating temperatures, a better molding effect can be obtained. Let the lengths of the first heating chamber 201, vacuum chamber 203, and tail heating chamber 210 be L1, L2, and L3, respectively. The range of L1:L2:L3 is (1.5-3):(1-2):1, and L2 is not less than 10 times the diameter of the thermoplastic composite material rib. The second heating component is specifically configured as heating rods 202. Multiple heating rods 202 are arranged at intervals along the pultrusion direction of the thermoplastic prepreg strip, and the axial direction of the heating rods 202 is perpendicular to the pultrusion direction of the thermoplastic prepreg strip. They are also positioned lower in the heating chamber. The specific number of heating rods 202 for the first heating chamber 201, vacuum chamber 203, and tail heating chamber 210 is set according to the actual temperature and heating rod parameters. The vacuum chamber 203 specifically includes a vacuum chamber processing channel 204. The vacuum pumping device 208 is ultimately connected to the vacuum chamber processing channel 204. The vacuum chamber processing channel 204 is also connected to adjacent chambers through a conical hole mold, i.e., a conical constraint component 5.

[0039] The cooling module 3, connected to the tail heating chamber 210, is used to cool the product. Each of the first heating chamber 201, the tail heating chamber 210, and the cooling module 3 is equipped with a conical constraint component 5. This conical constraint component 5 narrows the transmission path of the thermoplastic prepreg tape within its corresponding module. The conical constraint component 5 is funnel-shaped, gradually narrowing along the transmission path of the thermoplastic prepreg tape. It can be implemented using a mold, with the inner cavity of the mold forming a conical hole mold with a gradually narrowing radius. This constraint on the thermoplastic prepreg tape during its movement results in a more compact molding process, reducing defects such as bubbles. The method of connecting the mold module with the first heating chamber 201, the tail heating chamber 210, and the cooling module 3 allows for replacement of the mold module according to different processing requirements, reducing costs and improving production efficiency. The channel parameters of each conical hole mold corresponding to the first heating chamber 201, the tail heating chamber 210, and the cooling module 3 can be selected and set according to actual needs. In actual production, some units can be pre-produced according to certain standards for easy replacement when needed. The length of the conical constraint assembly 5 within the first heating chamber 201, the tail heating chamber 210, and the cooling module 3 can be selected according to actual needs, or it can be used in conjunction with a straight channel.

[0040] In this embodiment, the preheating module 1 includes a yarn guide plate 101, guide rollers 103, a heating device, a first preheating chamber 107, a last preheating chamber 108, and temperature sensors 109. The second end of the first preheating chamber 107 is connected to the first end of the last preheating chamber 108. Both the first end of the first preheating chamber 107 and the second end of the last preheating chamber 108 are provided with yarn guide plates 101. The yarn guide plates 101 are used to guide yarn into or out of the corresponding preheating chamber. Both the first preheating chamber 107 and the last preheating chamber 108 are provided with heating devices arranged along the pultrusion direction of the thermoplastic prepreg tape. Multiple temperature sensors 109 are arranged at intervals on the side wall of the first preheating chamber 107 along the pultrusion direction of the thermoplastic prepreg tape. Multiple guide rollers 103 are provided and distributed in a dot matrix pattern in the first preheating chamber 107. The axial direction of each guide roller 103 is perpendicular to the pultrusion direction of the thermoplastic prepreg tape. The temperature sensor 109 is used to monitor the temperature value at a corresponding location, thereby allowing for the appropriate selection of the working mode and state based on the temperature value. This ensures the smooth progress of the pultrusion molding process of the thermoplastic prepreg tape and guarantees the molding quality of the thermoplastic prepreg tape. The heating device within the preheating module 1 can be configured as a heating tube 105, located at the bottom of the first preheating chamber 107 and the tail preheating chamber 108. The heating tube 105 radiates heat upwards to preheat the thermoplastic prepreg tape. The extension direction of the heating tube 105 is consistent with the pultrusion direction of the thermoplastic prepreg tape. Corresponding to the arrangement of the heating tube 105, the temperature sensor 109 is positioned on the lower side wall of the first preheating chamber 107. Based on the radiation pattern of heat, heat is initially transferred upwards and then gradually moves downwards along the side wall. By appropriately positioning the temperature sensor 109, the temperature measured by the sensor 109 can accurately reflect the temperature within the first preheating chamber 107, thereby adjusting the temperature according to the state of the thermoplastic prepreg tape to achieve a better pultrusion molding effect. The first preheating chamber 107 has a top cover 102 on its upper part. The top cover 102 can be installed on the first preheating chamber 107 by means of snap-fit ​​or other means, and the connection between the two must be kept sealed. The first end of the first preheating chamber 107 and the outlet end of the tail heating chamber 210 are not sealed, thus forming a semi-closed structure of the device. The impregnation and molding processes are closely integrated, effectively reducing heat loss during the heating process and resulting in high molding efficiency. The guide roller 103 is specifically configured as a rolling type, driving the fiber to move in a rolling state. When the rolling guide roller 103 comes into contact with the thermoplastic prepreg tape, it transfers heat to the thermoplastic prepreg tape. The thermoplastic prepreg tape exchanges heat through convection with the rolling guide roller 103 and the infrared heating tube 105 via hot air. After being bundled in the first preheating chamber 107, the thermoplastic prepreg tape is bundled again in the tail preheating chamber 108.

[0041] In this embodiment, a plurality of thermoplastic prepreg tape inlet holes 104 are provided through the first end wall of the first preheating chamber 107, and all the thermoplastic prepreg tape inlet holes 104 correspond to the corresponding holes on the yarn guide plate 101. Specifically, the thermoplastic prepreg tape is guided through the yarn guide holes on the yarn guide plate 101 and enters the first preheating chamber 107 through the thermoplastic prepreg tape inlet holes 104 for preheating.

[0042] In this embodiment, a plurality of thermoplastic prepreg tape bundle holes 106 are provided through the second end wall of the tail preheating cavity 108, and all the thermoplastic prepreg tape bundle holes 106 correspond to the corresponding holes on the yarn guide plate 101. The thermoplastic prepreg tape bundle holes 106 are distributed in an aggregated manner, which facilitates the gathering and collection of thermoplastic prepreg tape.

[0043] In this embodiment, within the vacuum chamber 203, along the pultrusion direction of the thermoplastic prepreg tape, the air pressure gradually decreases from both sides towards the center. Let the atmospheric pressure of the outside air be P0, and set the pressure gradient from both ends of the chamber towards the center to be 0.2P0-0.5P0. The minimum air pressure at the vacuum extraction port within the vacuum chamber does not exceed 0.2P0. This gradient pressure distribution within the vacuum chamber 203, combined with the preheating device and the constraint effect of the conical constraint component 5, makes it easier for the resin to fully impregnate the fibers, reducing the possibility of bubbles and internal defects, and further improving the molding quality.

[0044] In this embodiment, the vacuum chamber 203 is provided with multiple sets of vacuum openings spaced apart along the pultrusion direction of the thermoplastic prepreg tape. Each set of vacuum openings includes two vacuum extraction ports 209 symmetrically arranged on both sides relative to the thermoplastic prepreg tape. Each vacuum extraction port 209 is provided with a vacuum extraction device 208. Along the pultrusion direction, the distance between each pair of adjacent sets of vacuum openings ranges from 50 to 200 mm. The vacuum extraction device 208 can be equipped with a pressure gauge 207 to control the pressure parameters, facilitating the formation of a stepped pressure distribution. Combined with the constraint effect of the conical constraint component 5, it can minimize the impact of defects such as bubbles on product quality. The vacuum extraction device 208 and the vacuum extraction port 209 can be connected by a vacuum extraction pipe 206. Necessary connection parts need to be bonded with sealant 205 to prevent air leakage. Vacuum chamber 205, aided by vacuum evacuation, utilizes the pressure difference between the chamber and the interior of the thermoplastic prepreg tape to remove air bubbles generated during the prepreg tape's own manufacturing process and those trapped between the tapes during melt impregnation, thereby further improving the impregnation degree of the prepreg tape. Specifically, vacuum evacuation device 208 can employ an air pump, with the conical mold correspondingly positioned within the primary heating chamber 201 extending 10mm into the vacuum chamber 205. In this embodiment, the spacing between any two adjacent sets of vacuum openings is set to 90mm.

[0045] In this embodiment, the two vacuum extraction ports 209 within each group of vacuum openings have the same air pressure. Specifically, three groups of vacuum openings are used, with pressure gauge readings along the pultrusion molding direction of -0.04 MPa, -0.08 MPa, and -0.04 MPa, respectively. Vacuum extraction devices 208 at the same gradient position have the same extraction pressure, with the vacuum extraction port 209 with a pressure gauge reading of -0.08 MPa located in the center of the vacuum chamber 203.

[0046] In this embodiment, the tapered constraint component 5 is a channel whose aperture gradually decreases along the direction of movement of the thermoplastic prepreg tape.

[0047] In this embodiment, the conical constraint component within the cooling module 3 is specifically the cooling cavity 301, which is also assembled within the cooling module 3 using a conical hole mold. The inner diameters of the conical hole molds of the cooling cavity 301 along the pultrusion molding direction are 21 mm and 20 mm, respectively.

[0048] In this embodiment, the device further includes a traction device 4, the traction end of which is connected to the thermoplastic prepreg tape for traction of the thermoplastic prepreg tape through the preheating module 1, the heating module 2 and the cooling module 3 in sequence.

[0049] According to another aspect of the present invention, a method for using the above-described vacuum-assisted pultrusion molding apparatus for thermoplastic composite reinforcement is provided, comprising the following steps: after the apparatus is installed, the first heating component and the second heating component are started; after the temperatures of the preheating module 1 and the heating module 2 are stabilized, a thermoplastic prepreg strip of a certain cross section is sequentially passed through the preheating module 1, the heating module 2 and the cooling module 3 and connected to the traction end of the traction device 4; the traction machine is started and the thermoplastic prepreg strip is pulled at a speed of 0.20 m / min; at the same time, the temperatures of the preheating module 1 and the heating module 2 are adjusted until the thermoplastic prepreg strip melts and is impregnated and stabilized; then all vacuum pumping devices 208 are started and the corresponding air pressure values ​​are adjusted to continuously pultrude the thermoplastic prepreg strip.

[0050] In the above description, thermoplastic prepreg tape includes continuous fiber reinforced polypropylene, nylon 6, or nylon 66-based thermoplastic prepreg tape, and the continuous fibers of the thermoplastic prepreg tape include glass fiber, basalt fiber, or carbon fiber. The diameter of the thermoplastic composite reinforcement ranges from 10 to 30 mm.

[0051] In this embodiment, the preheating temperatures of the first preheating chamber 107 and the last preheating chamber 108 are 150°C and 200°C, respectively, and the preheating times are 15 min and 5 min, respectively. The first heating chamber 201, the vacuum chamber 205, and the last heating chamber 212 are all steel cubic cavities with a through-hole, and each is equipped with several heating rods 202, which are connected in sequence through slots. Their lengths along the pultrusion direction are 400 mm, 200 mm, and 200 mm, respectively, and the heating temperatures are set to 240°C, 240°C, and 220°C, respectively. The inner diameters of the conical sections of the conical hole molds in the heating module 2 along the pultrusion direction are 28 mm, 24 mm, 23 mm, and 21 mm, respectively. Specific Implementation Method Two:

[0053] The object processed in this specific embodiment is a continuous carbon fiber reinforced nylon 6-rib with a diameter of 22mm. The difference from Specific Embodiment One lies in the different setting parameters of the specific components, specifically:

[0054] The first heating chamber 201, vacuum chamber 203, and tail heating chamber 210 are connected sequentially via slots, with lengths of 600mm, 400mm, and 200mm respectively along the pultrusion direction. The heating temperatures are set to 270℃, 270℃, and 255℃ respectively. The inner diameters of the tapered sections of the conical dies within the heating module along the pultrusion direction are 31mm, 27mm, 24mm, and 23mm respectively. Four sets of vacuum openings are specifically configured, with pressure gauge readings of -0.04MPa, -0.08MPa, -0.08MPa, and -0.04MPa along the pultrusion direction. The cooling chamber 301 has a length of 100mm, and the inner diameters of the tapered dies in the cooling chamber 301 along the pultrusion direction are 23mm and 22mm respectively.

[0055] In the two embodiments described above, by rationally setting various temperature parameters, pressure parameters, and the length and diameter parameters of the conical constraint component, bubble defects within the processed object can be effectively eliminated, ensuring the quality of the finished product. Simultaneously, the processing efficiency is high, the structure is simple, and the replacement cost of variable-parameter components is low, enabling better completion of pultrusion molding. The prepared thermoplastic composite ribs have low porosity and high fiber impregnation, meeting the performance requirements of high-fiber-content and large-diameter thermoplastic composite ribs.

[0056] The embodiments of the present invention disclosed above are merely illustrative of the invention. These embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention.

Claims

1. An apparatus for vacuum-assisted pultrusion molding of thermoplastic composite reinforcement bars, characterized in that, include: Preheating module (1) is used to preheat the thermoplastic prepreg tape; The heating module (2) includes a first heating chamber (201), a vacuum chamber (203), and a tail heating chamber (210) connected in sequence. The vacuum chamber (203) is connected to a vacuum pumping device (208) through a vacuum pumping port (209). A second heating component is installed in each of the first heating chamber (201), the vacuum chamber (203), and the tail heating chamber (210). The cooling module (3) is connected to the tail heating chamber (210) for cooling thermoplastic composite rib products. The first heating chamber (201), the tail heating chamber (210) and the cooling module (3) are all provided with conical constraint components (5). The conical constraint components (5) are used to narrow the transmission path of the thermoplastic prepreg tape in the corresponding module. The air pressure in the vacuum chamber (203) decreases gradually from the sides to the middle along the pultrusion direction of the thermoplastic prepreg tape. The vacuum chamber (203) is provided with multiple sets of vacuum openings arranged at intervals along the pultrusion direction of the thermoplastic prepreg tape. Each set of vacuum openings contains two vacuum extraction ports (209) arranged symmetrically on both sides relative to the thermoplastic prepreg tape. Each vacuum extraction port (209) is provided with a vacuum extraction device (208).

2. The apparatus for vacuum-assisted pultrusion molding of thermoplastic composite reinforcement according to claim 1, characterized in that: The preheating module (1) includes a yarn guide plate (101), a guide roller (103), a first heating component, a first preheating chamber (107), a last preheating chamber (108), and a temperature sensor (109). The second end of the first preheating chamber (107) is connected to the first end of the last preheating chamber (108). Both the first end of the first preheating chamber (107) and the second end of the last preheating chamber (108) are provided with yarn guide plates (101). The yarn guide plates (101) are used to guide the yarn in or out accordingly. The preheating chambers are provided with first heating components arranged along the pultrusion direction of the thermoplastic prepreg tape in both the first preheating chamber (107) and the tail preheating chamber (108). Multiple temperature sensors (109) are arranged at intervals on the side wall of the first preheating chamber (107) along the pultrusion direction of the thermoplastic prepreg tape. Multiple guide rollers (103) are provided and distributed in a dot matrix in the first preheating chamber (107). The axial direction of each guide roller (103) is perpendicular to the pultrusion direction of the thermoplastic prepreg tape.

3. The apparatus for vacuum-assisted pultrusion molding of thermoplastic composite reinforcement according to claim 2, characterized in that: Multiple thermoplastic prepreg tape inlet holes (104) are provided through the first end wall of the first preheating chamber (107), and all the thermoplastic prepreg tape inlet holes (104) correspond to the holes on the corresponding yarn guide plate (101).

4. The apparatus for vacuum-assisted pultrusion molding of thermoplastic composite reinforcement according to claim 2, characterized in that: Multiple thermoplastic prepreg tape bundle holes (106) are provided through the second end wall of the tail preheating cavity (108), and all the thermoplastic prepreg tape bundle holes (106) correspond to the holes on the corresponding yarn guide plate (101).

5. The apparatus for vacuum-assisted pultrusion molding of thermoplastic composite reinforcement according to claim 1, characterized in that: The two vacuum evacuation ports (209) in each set of vacuum openings have the same air pressure.

6. The apparatus for vacuum-assisted pultrusion molding of thermoplastic composite reinforcement according to claim 1, characterized in that: The tapered constraint component (5) is a channel whose aperture gradually decreases along the direction of movement of the thermoplastic prepreg tape.

7. An apparatus for vacuum-assisted pultrusion molding of thermoplastic composite reinforcement according to any one of claims 1-6, characterized in that: The device also includes a traction device, the traction end of which is connected to the thermoplastic prepreg tape for traction of the thermoplastic prepreg tape through the preheating module (1), the heating module (2) and the cooling module (3) in sequence.

8. A method for using an apparatus for vacuum-assisted pultrusion molding of thermoplastic composite reinforcement as described in any one of claims 1-6, characterized in that, The process includes the following steps: After installing and fixing each module and the vacuum pumping device (208), start the first heating component and the second heating component, and wait for the temperature of the preheating module (1) and the heating module (2) to stabilize; after passing the thermoplastic prepreg tape of a certain cross section through the preheating module (1), the heating module (2) and the cooling module (3) in sequence, connect it to the traction end of the traction device, start the traction device, and adjust the temperature of the preheating module (1) and the heating module (2) until the thermoplastic prepreg tape melts and is impregnated and stabilizes; Start all vacuum pumping devices (208) and adjust the air pressure value corresponding to each vacuum pumping device (208) according to the gradient, and use vacuum assistance to pultrude the thermoplastic prepreg tape.

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