An impregnation die

Abstract

The utility model relates to the technical field of composite material, more particularly to a kind of impregnation die, including first impregnation die and second impregnation die, the impregnation temperature in first impregnation die is greater than the impregnation temperature in second impregnation die;Tension module is equipped in first impregnation die, extrusion module is equipped in second impregnation die, the both ends of first impregnation die are respectively equipped with first feed inlet and first discharge port, the both ends of second impregnation die are respectively equipped with second feed inlet and second discharge port.The impregnation of long fiber is carried out in two sections, and the area of the outer periphery of the material strip changes during the two impregnation processes: on the one hand, sufficient impregnation can be carried out to achieve a comprehensive impregnation effect without white particles; on the other hand, the long fibers complete most of the resin impregnation in the first impregnation die, and the impregnation temperature in the second impregnation die can be low temperature impregnation, thereby ensuring that the toner required for bright color products is not affected by high temperature degradation to change color.

Description

Technical Field

[0001] This utility model relates to the technical field of composite materials, and more specifically, to an impregnation die head. Background Technology

[0002] With the rapid development of the new energy vehicle industry, lightweighting has become one of the key technologies for improving driving range. Long fiber reinforced thermoplastic composites (LFTs), with their excellent mechanical properties, high specific strength, good impact resistance, and high cost-effectiveness, are widely used in the field of automotive lightweighting, such as battery covers, power battery underbody panels, dashboard frames, and door panels. LFT materials typically use glass fiber (GF) or carbon fiber (CF) as the reinforcing phase and thermoplastic resins such as polypropylene (PP) and polyamide (PA) as the matrix, and are prepared through a melt impregnation process. Compared with short fiber reinforced materials, the long fiber structure of LFTs (fiber length is usually ≥5mm) can more effectively transfer loads, significantly improve the mechanical properties and fatigue resistance of the material, and meet the stringent operating conditions of automotive parts.

[0003] However, the large-scale industrial production of LFT materials still faces the following two technical problems: 1) During high-speed production, the difference in fluidity between fibers and resin can easily lead to uneven impregnation, forming an "eccentric structure"—that is, the fibers are unevenly distributed radially in the particles, and some areas of the fibers are not completely covered by the resin (commonly known as "exposed white"). This defect will reduce the consistency of the mechanical properties of the material and may cause local stress concentration after injection molding, affecting the fatigue life and reliability of the parts; 2) The impregnation process of LFT usually needs to be carried out at a high temperature above 280℃, while the heat resistance temperature of organic pigments with good heat resistance is generally only 270℃-280℃, which makes them prone to thermal degradation or oxidation during processing, causing problems such as color difference and fading in the products. This limitation makes it difficult for LFT materials to meet the requirements of automotive interior parts for high brightness and high weather resistance colors. Utility Model Content

[0004] The purpose of this invention is to overcome the problems of white exposure in LFT materials and impregnation temperature being higher than the degradation temperature of organic pigments in the prior art. It provides an impregnation die head that can not only avoid white exposure, but also effectively prevent the degradation of organic pigments caused by high temperature.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows: An impregnation die head is provided, including a first impregnation die and a second impregnation die. The impregnation temperature of the first impregnation die is higher than that of the second impregnation die. A tension module is provided in the first impregnation die, and an extrusion module is provided in the second impregnation die. A first inlet and a first outlet are respectively provided at both ends of the first impregnation die, and a second inlet and a second outlet are respectively provided at both ends of the second impregnation die. Fibers enter the first impregnation die from the first inlet, bypass the tension module, and sequentially pass through the first outlet and the second inlet to enter the second impregnation die. After bypassing or passing through the extrusion module, the fiber exits from the second outlet.

[0006] The impregnation die head of this invention includes two impregnation stages: a first impregnation die and a second impregnation die. A tension module within the first impregnation die tensions the long fibers, ensuring thorough resin impregnation. In the second impregnation die, the cross-sectional shape of the fiber strip changes due to compression. After the second impregnation stage, the surface area of ​​the fiber strip increases, allowing it to be coated with resin over a larger area. The strip is then shaped and discharged through a second outlet. The impregnation of the long fibers in this invention is performed in two stages, and the area of ​​the outer periphery of the fiber strip changes during these stages: on the one hand, thorough impregnation is achieved, resulting in a complete impregnation effect without exposed white particles; on the other hand, since most of the resin impregnation is completed in the first impregnation die, a lower impregnation temperature can be used in the second impregnation die, thus ensuring that the pigments required for brightly colored products are not affected by high-temperature degradation and discoloration.

[0007] Furthermore, the tension module includes several rotatably arranged tension rollers. The fibers sequentially pass around each tension roller and are discharged from the first discharge port to obtain a first strip with a first elliptical cross-section. The elliptical cross-section of the first discharge port serves to shape the first strip obtained by impregnation in the first impregnation mold.

[0008] Furthermore, the tension rollers are elliptical cylindrical rollers, and the centers of each elliptical cylindrical roller are located on the central axis of the first impregnation mold. By setting the rotation angle of the elliptical cylindrical rollers, the tension of the tension rollers on the long fibers can be adjusted, which can easily adjust the tension of the long fibers according to the impregnation requirements and has a wide range of applications.

[0009] Furthermore, the extrusion module includes several rotating impregnation rollers. The first strip is sequentially passed around each of the impregnation rollers, subjected to extrusion and impregnation, to obtain a second strip with a cross-sectional shape of a second ellipse. The minor axis diameter of the second ellipse is smaller than that of the first ellipse, and the major axis diameter of the second ellipse is larger than that of the first ellipse. When the spacing between the impregnation rollers is smaller than the minor axis diameter of the first strip, the impregnation rollers can exert an extrusion effect on the first strip, flattening its cross-sectional shape. Impregnating the flattened strip surface yields a second strip with a larger outer circumferential surface area.

[0010] Furthermore, the impregnation rollers are cylindrical rollers, with the center of each roller offset from the central axis of the second impregnation mold, and the centers of adjacent rollers located on opposite sides of the central axis of the second impregnation mold. This cylindrical roller shape and position simplifies the design of the impregnation rollers, allowing for the flattening of the material strip's cross-sectional shape using a simple structure, thus facilitating thorough impregnation in the second stage.

[0011] Furthermore, the impregnation roller is slidably connected to the second impregnation mold, and the sliding direction of the impregnation roller is perpendicular to the fiber conveying direction and the axial direction of the impregnation roller. The vertical position of the impregnation roller can be adjusted as needed, thereby achieving a controllable pressure-adjustable impregnation effect.

[0012] Furthermore, the inner cavity of the second impregnation mold includes a first impregnation cavity and a second impregnation cavity arranged sequentially. The impregnation rollers are all located within the first impregnation cavity. The cross-sectional area of ​​the second impregnation cavity gradually decreases along the fiber conveying direction. The second discharge port is connected to the end of the second impregnation cavity. This gradually decreasing size of the second impregnation cavity allows for further compression of the resin around the outer periphery of the second strip. After shaping at the second discharge port, an impregnated product without any exposed white surface can be obtained.

[0013] Furthermore, the second discharge port is a circular hole. The circular hole is used to shape the second material strip into a cylindrical material strip.

[0014] Furthermore, a pre-cooling gap is provided between the first impregnation mold and the second impregnation mold. The impregnation temperature of the second impregnation mold is lower than that of the first impregnation mold. The pre-cooling gap is designed to bring the temperature of the first strip closer to the impregnation temperature of the second impregnation mold, thereby facilitating accurate temperature control of the second impregnation mold.

[0015] Furthermore, the first impregnation mold is provided with a plurality of first feeding ports, and the second impregnation mold is provided with a plurality of second feeding ports, wherein the total feeding flow rate of each first feeding port is greater than the total feeding flow rate of each second feeding port. Specifically, it can be configured such that 80% of the resin is fed into the first feeding ports, while 20% of the resin is fed into the second feeding ports, thereby reducing the impregnation temperature of the second impregnation mold while ensuring the impregnation effect.

[0016] Compared with the prior art, the beneficial effects of this utility model are: The impregnation die head of this utility model impregnates long fibers in two stages, and the area of ​​the outer periphery of the material strip changes during the two stages of impregnation: on the one hand, it can be fully impregnated to achieve a comprehensive impregnation effect without exposed white particles; on the other hand, the long fibers complete most of the resin impregnation in the first impregnation die, and the impregnation temperature in the second impregnation die can be lowered to ensure that the color powder required for bright color products is not affected by high temperature degradation and changes color. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of an impregnation die head; Figure 2 This is a schematic diagram of the structure of the first impregnation mold; Figure 3 This is a schematic diagram of the structure of the second impregnation mold; In the attached diagram: 100, first impregnation mold; 110, tension module; 120, first feed inlet; 130, first discharge outlet; 140, first feed port; 200, second impregnation mold; 210, extrusion module; 220, second feed inlet; 230, second discharge outlet; 240, first impregnation chamber; 250, second impregnation chamber; 260, second feed port; 270, support roller; 300, pre-cooling gap; 400, fiber. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0019] The present invention will be further described below with reference to specific embodiments. The accompanying drawings are for illustrative purposes only, representing schematic diagrams rather than actual physical objects, and should not be construed as limiting the scope of this patent. To better illustrate the embodiments of the present invention, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0020] In the accompanying drawings of this utility model, the same or similar reference numerals correspond to the same or similar components. In the description of this utility model, it should be understood that if terms such as "upper," "lower," "left," and "right" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting this patent. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0021] Example 1 This embodiment is a first embodiment of an impregnation die head, including a first impregnation die 100 and a second impregnation die 200. The impregnation temperature of the first impregnation die 100 is higher than that of the second impregnation die 200. A tension module 110 is provided inside the first impregnation die 100, and an extrusion module 210 is provided inside the second impregnation die 200. A first inlet 120 and a first outlet 130 are respectively provided at both ends of the first impregnation die 100, and a second inlet 220 and a second outlet 230 are respectively provided at both ends of the second impregnation die 200. Fiber 400 enters the first impregnation die 100 through the first inlet 120, bypasses the tension module 110, and sequentially passes through the first outlet 130 and the second inlet 220 into the second impregnation die 200. After bypassing or passing through the extrusion module 210, it exits through the second outlet 230. Figure 1 As shown.

[0022] In this embodiment, the impregnation is carried out in two stages. The tension module 110 in the first impregnation mold 100 is used to tension the long fiber 400 so that the long fiber 400 is fully impregnated with resin. In the second impregnation mold 200, the material strip is squeezed and the cross-sectional shape changes, and the surface area of ​​the material strip increases. The extruded material strip can be covered with resin over a larger area and is discharged after being shaped through the second discharge port 230. During implementation, the impregnation of long fiber 400 is carried out in two stages, and the area of ​​the outer periphery of the strip changes during the two stages of impregnation: on the one hand, it can be fully impregnated to achieve a comprehensive impregnation effect without exposed white particles; on the other hand, the long fiber 400 completes most of the resin impregnation in the first impregnation mold 100, and the impregnation temperature in the second impregnation mold 200 can be lowered to ensure that the color powder required for bright color products is not affected by high temperature degradation and discoloration; when polypropylene is selected as the thermoplastic resin matrix, the impregnation temperature in the first impregnation mold 100 is 290℃-330℃, and the impregnation temperature in the second impregnation mold 200 is 220℃-260℃.

[0023] In this embodiment, the tension module 110 includes several rotatably arranged tension rollers. The fiber 400 sequentially passes over each tension roller and exits through the first discharge port 130 to obtain a first strip with a cross-sectional shape of a first ellipse. Figure 2 As shown, the cross-section of the first discharge port 130 is elliptical, which plays a shaping role in the first strip obtained by impregnation in the first impregnation mold 100, and avoids the phenomenon of white showing.

[0024] Specifically, in this embodiment, the tension rollers are elliptical cylindrical rollers, and the centers of each elliptical cylindrical roller are located on the central axis of the first impregnation mold 100. By setting the rotation angle of the elliptical cylindrical rollers, the tension of the tension rollers on the long fibers 400 can be adjusted, which can conveniently adjust the tension of the long fibers 400 according to the impregnation requirements and has a wide range of applications. The cross-sectional shape of the first strip after being shaped by the first discharge port 130 is a first ellipse. The first strip is extruded by the extrusion module 210 and impregnated twice in the second impregnation mold 200 to obtain a second strip with a cross-sectional shape of a second ellipse. The minor axis diameter of the second ellipse is smaller than that of the first ellipse, the major axis diameter of the second ellipse is larger than that of the first ellipse, and the circumference of the second ellipse is greater than that of the first ellipse.

[0025] The extrusion module 210 of this embodiment can be configured as an impregnation block having a shaping hole with a second elliptical cross-section. When the first strip with a first elliptical cross-section passes through the shaping hole, the resin is still soft at this time, and the first strip will deform to obtain a second strip with a second elliptical cross-section. The extrusion module 210 of this embodiment can also be a plurality of rotating rollers, the minimum distance between the roller surfaces of adjacent rotating rollers being less than the minor axis diameter of the first ellipse. In this case, when the first strip passes between two rotating rollers, it will be compressed and deformed, and after passing through the second impregnation stage, a second strip with a second elliptical cross-section is obtained. It should be noted that any extrusion module 210 that can generate a compression effect on the first strip to change its cross-sectional shape and obtain a second elliptical cross-section after the second impregnation stage can be applied to this utility model.

[0026] Additionally, the inner cavity of the second impregnation mold 200 includes a first impregnation cavity 240 and a second impregnation cavity 250 arranged sequentially. The extrusion module 210 is disposed within the first impregnation cavity 240. The cross-sectional area of ​​the second impregnation cavity 250 gradually decreases along the conveying direction of the fiber 400. The second discharge port 230 is connected to the end of the second impregnation cavity 250. Figure 3 As shown. Specifically, in this embodiment, the wall surface of the first impregnation chamber 240 can be configured as a cylindrical structure, the wall surface of the second impregnation chamber 250 is an arc-shaped structure that smoothly transitions to the cylindrical structure, and the second discharge port 230 is a circular hole. In this embodiment, the first strip first passes through the extrusion module 210 in the first impregnation chamber 240 for varying extrusion, while simultaneously undergoing a second stage of impregnation, resulting in a second strip with a second elliptical cross-section. The gradually decreasing size of the second impregnation chamber 250 further compresses the resin around the outer periphery of the second strip. After shaping through the second discharge port 230, an impregnated product with a circular cross-section and no exposed white surface can be obtained.

[0027] Example 2 This embodiment is a second embodiment of the impregnation die head. This embodiment is similar to the first embodiment, except that the extrusion module 210 includes several rotatably arranged impregnation rollers, all located within the first impregnation cavity 240. The first strip sequentially passes over each impregnation roller, undergoing extrusion and impregnation to obtain a second strip with a cross-sectional shape of a second ellipse. When the distance between the impregnation roller surfaces is less than the minor axis diameter of the first strip, the impregnation rollers can exert an extrusion effect on the first strip, causing changes in the cross-sectional shape and outer circumferential surface area of ​​the first strip. Thus, after completing the second impregnation stage, a second strip with a cross-section of a second ellipse is obtained. The minor axis diameter of the second ellipse is smaller than that of the first ellipse, the major axis diameter of the second ellipse is larger than that of the first ellipse, and the circumference of the second ellipse is greater than that of the first ellipse.

[0028] In this embodiment, the impregnation rollers are cylindrical rollers, and at least two impregnation rollers are arranged along the fiber 400 conveying direction. The center of each impregnation roller is offset from the central axis of the second impregnation mold 200. The shape and position of the cylindrical rollers simplify the design of the impregnation rollers, and the cross-sectional shape of the material strip can be flattened from the first ellipse and then impregnated to obtain the second ellipse using a simple structure. To facilitate the smooth drawing of long fibers from the first impregnation mold 100 into the gap between the impregnation rollers in the second impregnation mold 200, this embodiment provides a fixedly arranged support roller 270 near the second feed inlet 220 in the second impregnation mold 200. Figure 3 As shown.

[0029] Specifically, in this embodiment, the centers of two adjacent impregnation rollers are located on the upper and lower sides of the central axis of the second impregnation mold 200, and the minimum distance between the outer circumferential surfaces of two adjacent impregnation rollers in the vertical direction is less than the minor axis diameter of the first ellipse. In this embodiment, the vertical direction is perpendicular to the fiber 400 conveying direction and the impregnation roller axis direction.

[0030] In addition, in this embodiment, the impregnation roller is slidably connected to the second impregnation mold 200, and the sliding direction of the impregnation roller is perpendicular to the conveying direction of the fiber 400 and the axial direction of the impregnation roller. The vertical position of the impregnation roller can be adjusted as needed, thereby adjusting the minimum distance between the outer peripheral surfaces of two adjacent impregnation rollers in the vertical direction, thereby achieving a controllable pressure adjustment impregnation effect and making it more widely applicable.

[0031] Example 3 This embodiment is the third embodiment of the impregnation die head. This embodiment is similar to Embodiment 1 or Embodiment 2, except that a pre-cooling gap 300 is provided between the first impregnation die 100 and the second impregnation die 200. Figure 1As shown. That is, in this embodiment, the first impregnation mold 100 and the second impregnation mold 200 are two independent impregnation modules. During the process of the first strip being conveyed from the first impregnation mold 100 to the second impregnation mold 200, it passes through the pre-cooling gap 300. In the pre-cooling gap 300, the first strip comes into contact with air and cools down. The temperature of the first strip approaches the impregnation temperature of the second impregnation mold 200, so as to help the second impregnation mold 200 accurately control the temperature.

[0032] The first impregnation mold 100 is provided with a plurality of first feeding ports 140, and the second impregnation mold 200 is provided with a plurality of second feeding ports 260. The total feeding flow rate of all first feeding ports 140 is greater than the total feeding flow rate of all second feeding ports 260. Figure 2 , 3 As shown. Specifically, it can be set so that 80% of the resin is fed into the first feeding port 140, and 20% of the resin is fed into the second feeding port 260, thereby reducing the impregnation temperature of the second impregnation mold 200 while ensuring the impregnation effect. In addition to using a two-stage feeding ratio of 80% and 20%, feeding ratios of 70% and 30%, and 75% and 25% are also possible. The first impregnation mold 100 is mainly used for impregnating most of the resin on the surface of the long fiber 400. The temperature of the second impregnation mold 200 is lower than that of the first impregnation mold 100. Organic pigments that are prone to degradation at high temperatures are mixed into the resin in the second impregnation mold 200, which can effectively prevent the organic pigments from decomposing at high temperatures and causing color differences.

[0033] In the specific implementation of the above embodiments, the technical features can be combined in any non-contradictory way. For the sake of brevity, not all possible combinations of the above technical features are described. However, as long as the combination of these technical features is not contradictory, it should be considered to be within the scope of this specification.

[0034] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating this utility model, and are not intended to limit the implementation of this utility model. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. An impregnation die head, characterized in that, The device includes a first impregnation mold (100) and a second impregnation mold (200), wherein the impregnation temperature of the first impregnation mold (100) is higher than that of the second impregnation mold (200); the first impregnation mold (100) is provided with a tension module (110), and the second impregnation mold (200) is provided with an extrusion module (210); the first impregnation mold (100) has a first feed port (120) and a first discharge port (130) at its two ends, respectively. The two ends of the two impregnation molds (200) are respectively provided with a second feed port (220) and a second discharge port (230). The fiber (400) enters the first impregnation mold (100) from the first feed port (120), bypasses the tension module (110), and then sequentially passes through the first discharge port (130) and the second feed port (220) into the second impregnation mold (200). After bypassing or passing through the extrusion module (210), it is discharged from the second discharge port (230).

2. The impregnation die head according to claim 1, characterized in that, The tension module (110) includes several rotatably arranged tension rollers. The fiber (400) passes through each tension roller in sequence and is discharged from the first discharge port (130) to obtain a first strip with a cross-sectional shape of a first ellipse.

3. The impregnation die head according to claim 2, characterized in that, The tension rollers are elliptical cylindrical rollers, and the center of each elliptical cylindrical roller is located on the central axis of the first impregnation mold (100).

4. The impregnation die head according to claim 2, characterized in that, The extrusion module (210) includes several rotating impregnation rollers. The first strip is extruded and impregnated sequentially around each of the impregnation rollers to obtain a second strip with a cross-sectional shape of a second ellipse. The minor axis diameter of the second ellipse is smaller than the minor axis diameter of the first ellipse, and the major axis diameter of the second ellipse is larger than the major axis diameter of the first ellipse.

5. The impregnation die head according to claim 4, characterized in that, The impregnation rollers are cylindrical rollers, and the center of each impregnation roller is offset from the central axis of the second impregnation mold (200), and the centers of two adjacent impregnation rollers are respectively located on both sides of the central axis of the second impregnation mold (200).

6. The impregnation die head according to claim 5, characterized in that, The impregnation roller is slidably connected to the second impregnation mold (200), and the sliding direction of the impregnation roller is perpendicular to the conveying direction of the fiber (400) and the axial direction of the impregnation roller.

7. The impregnation die head according to claim 4, characterized in that, The inner cavity of the second impregnation mold (200) includes a first impregnation cavity (240) and a second impregnation cavity (250) arranged in sequence. The impregnation rollers are all disposed in the first impregnation cavity (240). The cross-sectional area of ​​the second impregnation cavity (250) gradually decreases along the conveying direction of the fiber (400). The second discharge port (230) is connected to the end of the second impregnation cavity (250).

8. The impregnation die head according to claim 7, characterized in that, The second discharge port (230) is a round hole.

9. The dipping die head according to any one of claims 1 to 8, characterized in that, A pre-cooling gap (300) is provided between the first impregnation mold (100) and the second impregnation mold (200).

10. The dipping die head according to any one of claims 1 to 8, characterized in that, The first impregnation mold (100) is provided with a plurality of first feeding ports (140), and the second impregnation mold (200) is provided with a plurality of second feeding ports (260). The total feeding flow rate of each first feeding port (140) is greater than the total feeding flow rate of each second feeding port (260).

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