Continuous fiber reinforced thermoplastic composite prepreg melt impregnation mold and impregnation process thereof

Abstract

The present invention discloses a continuous fiber reinforced thermoplastic composite material prepreg melt impregnation mold, comprising an upper mold and a lower mold and a driving device for driving the upper mold to open and close, an impregnation channel is formed between the upper mold and the lower mold, an upper heating device and a lower heating device are respectively provided on the upper mold and the lower mold, an upper mold flow channel and a lower mold flow channel are respectively provided in the upper mold and the lower mold, and the upper mold flow channel and the lower mold flow channel are respectively connected to the feed port, the upper mold is located in the impregnation channel and a plurality of upper impregnation rollers are arranged at intervals along the direction of the continuous fiber, the lower mold is located in the impregnation channel and a plurality of lower impregnation rollers are arranged at intervals along the direction of the continuous fiber, and the plurality of upper impregnation rollers and the plurality of lower impregnation rollers are arranged at intervals along the direction of the continuous fiber, so that the impregnation channel forms a W-shaped impregnation channel. The present invention also discloses an impregnation process using a continuous fiber reinforced thermoplastic composite material prepreg melt impregnation mold.

Description

Technical Field

[0001] The invention relates to the technical field of polymer composite materials, in particular to a continuous fiber reinforced thermoplastic composite material prepreg melt impregnation die and an impregnation process thereof. Background Art

[0002] Continuous fiber-reinforced thermoplastic composites (CFRT) use continuous fibers as reinforcement and a thermoplastic resin as a matrix. CFRT utilizes a process of melt-impregnating the thermoplastic resin into the fibers to create high-strength, high-rigidity, and high-toughness composite materials. CFRTs, which utilize continuous glass fiber, carbon fiber, aramid fiber, and basalt fiber to reinforce thermoplastic resins such as PP, PE, PA6, PA66, PC, PET, TPU, PPS, and PEEK, offer lightweight, high-rigidity, and high-toughness properties, and are widely used in a variety of fields, including automotive, aerospace, military, and electronics.

[0003] At present, the domestic equipment for preparing continuous fiber reinforced thermoplastic composite prepregs basically adopts the method of melt impregnation of thermoplastic resin into fibers. For example, patents CN200810201216.9 and CN200910030336.1 adopt double-sided glue coating impregnation. This impregnation method is simple and easy to clean. However, after the resin melt contacts the fiber, the temperature drops rapidly, the viscosity increases, and the impregnation effect between the fibers is poor.

[0004] Another patent, CN201110296640.8, uses an arc-shaped resin channel for impregnation. The impregnation is divided into a primary impregnation tank and a secondary impregnation tank. The secondary impregnation tank is provided with an arc-shaped channel filled with molten resin. The gap of the arc-shaped channel is 3mm. The primary impregnation tank is outside the arc-shaped channel. After the initial impregnation of the fiber, it needs to be heated and impregnated again when entering the arc-shaped channel, which increases energy consumption and process steps. Patent CN201410084598.7 uses a "V"-shaped resin channel to complete fiber impregnation. There are several troughs and peaks that make up the impregnation channel. The hot-melt resin channel is selected to be perpendicular to the continuous fiber conveying channel in front of the feeding area. The molten resin enters the impregnation channel from one side, which is not conducive to the impregnation of both sides of the fiber. In addition, once the impregnation molds in these two patents are determined, the gap in the "arc-shaped channel" and the wrap angle of the fiber on the "peaks" and "troughs" cannot be changed, and they are not well suited for the production of multiple fibers. This is because different fiber types and yarn thicknesses (number of strands or weight per length) require different impregnation roller diameters, wrap angles, and channel gaps. Furthermore, different thermoplastic resins, due to varying processing viscosities and fluidities, require different impregnation roller numbers, diameters, and wrap angles. This makes it even more challenging to achieve optimal results using a single melt impregnation mold for multiple resin and fiber prepregs. Summary of the Invention

[0005] The purpose of the present invention is to provide a continuous fiber reinforced thermoplastic composite material prepreg melt impregnation mold and an impregnation process thereof to solve the above-mentioned deficiencies and defects of the prior art, so as to solve the above-mentioned problems.

[0006] The technical problem solved by the present invention can be achieved by adopting the following technical solutions:

[0007] A continuous fiber reinforced thermoplastic composite material prepreg melt impregnation mold includes an upper mold and a lower mold and a drive device for driving the upper mold to open and close, an impregnation channel is formed between the upper mold and the lower mold, an upper heating device and a lower heating device are respectively provided on the upper mold and the lower mold, an upper mold runner and a lower mold runner are respectively provided in the upper mold and the lower mold, the upper mold runner and the lower mold runner are respectively connected to the feed port, the upper mold is located in the impregnation channel and a plurality of upper impregnation rollers are arranged at intervals along the direction of the continuous fibers, the lower mold is located in the impregnation channel and a plurality of lower impregnation rollers are arranged at intervals along the direction of the continuous fibers, the plurality of upper impregnation rollers and the plurality of lower impregnation rollers are staggered along the direction of the continuous fibers, so that the impregnation channel forms a W-shaped impregnation channel.

[0008] In a preferred embodiment of the present invention, a plurality of upper dipping rollers and a plurality of lower dipping rollers are respectively mounted on the upper mold and the lower mold via detachable connecting pieces.

[0009] In a preferred embodiment of the present invention, the protrusion lengths of the plurality of upper impregnation rollers and the plurality of lower impregnation rollers are distributed from low to high along the direction of the continuous fiber, the top arc surface diameters of the plurality of upper impregnation rollers and the plurality of lower impregnation rollers are distributed from small to large along the direction of the continuous fiber, and the spacing distance between the plurality of upper impregnation rollers and the plurality of lower impregnation rollers is distributed from wide to narrow along the direction of the continuous fiber.

[0010] In a preferred embodiment of the present invention, the upper mold runner and the lower mold runner are distributed perpendicular to the direction of the continuous fibers.

[0011] In a preferred embodiment of the present invention, the discharge ports of the upper mold runner and the lower mold runner are in a necked extrusion structure.

[0012] In a preferred embodiment of the present invention, the upper mold and the lower mold are respectively provided with an upper mold side frame and a lower mold side frame, and the upper mold side frame and the lower mold side frame are respectively provided with an internal longitudinal flow channel of the upper mold side frame and an internal longitudinal flow channel of the lower mold side frame, and the internal longitudinal flow channel of the upper mold side frame and the internal longitudinal flow channel of the lower mold side frame are respectively provided with melt flow regulating components, and one end of the internal longitudinal flow channel of the upper mold side frame and the internal longitudinal flow channel of the lower mold side frame are respectively connected to the feed port of the upper mold runner and the lower mold runner, and the other end of the internal longitudinal flow channel of the upper mold side frame and the internal longitudinal flow channel of the lower mold side frame are respectively connected to the feed port.

[0013] In a preferred embodiment of the present invention, the feed port is arranged on a material dividing component, and the material dividing component is provided with an upper material dividing port and a lower material dividing port that are connected to the other end of the longitudinal flow channel inside the upper mold side frame and the longitudinal flow channel inside the lower mold side frame.

[0014] In a preferred embodiment of the present invention, a melt stopper is provided on the fiber yarn inlet of the impregnation channel to prevent the melt from flowing back.

[0015] In a preferred embodiment of the present invention, the upper die lip of the upper die is provided with a lip gap adjustment device.

[0016] A process for impregnating a mold using a continuous fiber reinforced thermoplastic composite prepreg melt impregnated as described in any of the above technical solutions comprises the following steps:

[0017] Step 1:

[0018] According to the processing temperature of the resin, close the impregnation mold in advance and heat it to the specified temperature. After keeping it for 1-2 hours, adjust the appropriate die lip gap;

[0019] Step 2:

[0020] Operate the drive device, open the upper mold, and let the continuous fiber after yarn arrangement and yarn spreading pass through the fiber yarn inlet of the mold, pass out from the mold lip, and lead it to the position of the traction machine. Start the traction machine to continuously pull out the continuous fiber until a yarn layer is neatly arranged and evenly spread.

[0021] Step 3:

[0022] Pour the resin raw material into the extruder barrel, start the extruder, let the resin melt squeeze into the mold through the feed port, transport the molten resin to the upper mold runner and the lower mold runner, and then flow out of the mold and use the laminating method to spray the resin melt onto the continuous fiber;

[0023] Step 4:

[0024] The continuous fiber impregnated with resin melt passes through several upper and lower impregnation rollers for tensioning and friction, so that the resin melt is more evenly impregnated on the fiber, and the excess resin melt remains in the cavity of the mold;

[0025] Step 5:

[0026] The continuous fibers impregnated with resin are pulled, shaped, and cooled to obtain continuous fiber reinforced thermoplastic composite prepreg.

[0027] Due to the adoption of the above technical solution, the present invention has the following advantages:

[0028] 1. There is an impregnation roller inside the mold. When the continuous fiber passes through the mold, the path is in a "W" shape. The continuous fiber and the resin melt are impregnated inside the impregnation mold. Firstly, the temperature of the resin melt is guaranteed. Secondly, the fiber and the resin melt are tensioned and rubbed by the impregnation roller, so that the resin melt can be more evenly impregnated on the fiber. In addition, the impregnation roller is detachable and can be replaced according to different fibers and resins, so that one mold can be used for multiple purposes and reduce mold opening costs.

[0029] 2. There are two resin melt flow channels in the impregnation mold with a simple and detachable structure. After the resin is extruded by the extruder die head, it is divided into two in the impregnation mold and passes through the two flow channels. The melt flow rate can be independently adjusted by the flow channel adjustment component. All flow channels are in the mold, which not only keeps the heat but also does not add other external structures, saving mold costs.

[0030] 3. The impregnation mold is a composite type, and the upper mold can be opened and closed by a driving device, which is easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order 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 use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0032] Figure 1 This is a structural diagram of an embodiment of the present invention.

[0033] Figure 2 This is a schematic diagram of the internal structure of an embodiment of the present invention.

[0034] Figure 3 This is a schematic diagram of a lower mold according to an embodiment of the present invention.

[0035] Figure 4 FIG1 is an external schematic diagram of a resin melt feeding path according to an embodiment of the present invention.

[0036] Figure 5 This is a schematic diagram of the interior of the resin melt feeding path according to an embodiment of the present invention.

[0037] Figure 6 This is a schematic diagram of an upper mold side frame according to an embodiment of the present invention. DETAILED DESCRIPTION

[0038] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below.

[0039] See also Figures 1 to 6The mold shown here for melt impregnation of continuous fiber-reinforced thermoplastic composite prepregs comprises an upper mold 1 and a lower mold 2, and a drive mechanism 5 for opening and closing the upper mold 1. In this embodiment, the drive mechanism 5 comprises a connecting rod 5a connected to the upper mold 1 and a piston 5b for driving the connecting rod 5a. An impregnation channel 27 is formed between the upper mold 1 and the lower mold 2. Upper and lower heating devices are provided on the upper and lower molds 1, respectively. In this embodiment, the upper and lower heating devices are heating rods 7a and 7b provided on the upper and lower molds 1, respectively.

[0040] The upper mold 1 and lower mold 2 are respectively provided with an upper mold runner 17 and a lower mold runner 16, which are respectively connected to the feed port. To ensure uniform melt flowability, the upper mold runner 17 and the lower mold runner 16 in this embodiment are arranged perpendicular to the direction of the continuous fiber, and the discharge ports of the upper mold runner 17 and the lower mold runner 16 are formed into a constricted extrusion structure 23 and 24. In this embodiment, an upper mold runner insert 21 and a lower mold runner insert 22 are embedded in the corresponding positions of the upper mold runner 17 and the lower mold runner 16 to form the upper mold runner 17 and the lower mold runner 16 and the constricted extrusion structure 23 and 24, making it easy to replace the upper mold runner insert 21 and the lower mold runner insert 22 according to different fibers and resins.

[0041] The upper die 1 is located within the impregnation channel 27 and has a plurality of upper impregnation rollers 19a spaced along the direction of the continuous fiber. The lower die 2 is located within the impregnation channel 27 and has a plurality of lower impregnation rollers 19b spaced along the direction of the continuous fiber. The plurality of upper impregnation rollers 19a and the plurality of lower impregnation rollers 19b are staggered along the direction of the continuous fiber, forming a W-shaped impregnation channel 27. When the continuous fiber passes through the impregnation die, its path forms a "W" shape. The continuous fiber and the resin melt are impregnated within the impregnation die. This not only ensures the temperature of the resin melt, but also allows the fiber and the resin melt to be more evenly impregnated by the tension and friction of the impregnation rollers. In this embodiment, the upper and lower impregnation rollers 19a and 19b are mounted on the upper and lower molds 1 and 2, respectively, via detachable connectors 20, which are countersunk screws. The upper and lower impregnation rollers 19a and 19b are detachable and can be replaced according to different fibers and resins, enabling a single mold to be used for multiple purposes and reducing mold manufacturing costs. To ensure more uniform impregnation of the resin melt onto the fibers, the protrusion lengths of the upper and lower impregnation rollers 19a and 19b are distributed from low to high along the direction of the continuous fibers. The diameters of the top arc surfaces of the upper and lower impregnation rollers 19a and 19b are distributed from small to large along the direction of the continuous fibers. The spacing between the upper and lower impregnation rollers 19a and 19b is distributed from wide to narrow along the direction of the continuous fibers. The varying dimensions of these three parameters are determined by the overall mold size.

[0042] The upper mold 1 and lower mold 2 are respectively provided with an upper mold side frame 61 and a lower mold side frame 62. The upper mold side frame 61 and the lower mold side frame 62 are respectively provided with an upper mold side frame internal longitudinal flow channel 15 and a lower mold side frame internal longitudinal flow channel 16. The upper mold side frame internal longitudinal flow channel 15 and the lower mold side frame internal longitudinal flow channel 16 are respectively provided with a melt flow adjustment component 8, which is an adjustment screw, and the melt flow rate can be independently adjusted by the adjustment screw. One end of the upper mold side frame internal longitudinal flow channel 15 and the lower mold side frame internal longitudinal flow channel 16 are respectively connected to the feed port of the upper mold runner 17 and the lower mold runner 16, and the other end of the upper mold side frame internal longitudinal flow channel 15 and the lower mold side frame internal longitudinal flow channel 16 are respectively connected to the feed port. In this embodiment, the feed inlet 10 is located on the material distribution member 3. The material distribution member 3 is provided with an upper material distribution port 11 and a lower material distribution port 12, which connect to the other ends of the longitudinal flow channel 15 and the longitudinal flow channel 16 within the upper mold side frame. The material distribution member 3 can be a fixed column. All flow channels in this invention are located within the mold, which provides thermal insulation without adding other external structures, simplifies the process, and reduces mold costs.

[0043] In order to prevent the melt from flowing back, a melt stopper 26 is provided on the fiber yarn inlet 25 of the impregnation channel 27 to prevent the melt from flowing back.

[0044] The upper die lip 4 of the upper die 1 is provided with a lip gap adjustment device 13. The lip gap adjustment device 13 is the same as the lip adjustment bolt in the prior art, which realizes push-pull adjustment of the die lip gap, thereby improving the applicability of the die and the thickness uniformity of the product.

[0045] The tail flip portion of the upper mold side frame 61 in this embodiment is provided with a rotating yield edge, and the angle α18 of the rotating yield edge is 150°-165°, so that when the driving device 5 drives the upper mold 1 to rotate, the upper mold 1 can open a suitable angle. If the angle α is too large, the opening angle of the upper mold 1 is too small, affecting the continuous fiber threading and the cleaning of the hot melt resin in the mold cavity; if the angle α is too small, the opening angle of the upper mold 1 will be too large, and a too large opening will easily cause the mold to dissipate heat too quickly, which is not conducive to heat preservation, and the output end of the driving device 5 that drives the upper mold 1 to open and close must be lengthened, which affects the overall structure of the mold and is not beautiful.

[0046] A process for impregnating a mold by melt-impregnating a continuous fiber reinforced thermoplastic composite prepreg comprises the following steps:

[0047] Step 1:

[0048] According to the processing temperature of the resin, the impregnation mold is closed in advance and heated to the specified temperature. After maintaining it for 1-2 hours, the appropriate die lip gap is adjusted through the lip gap adjustment device 13. The general gap is 0.2-0.5mm;

[0049] Step 2:

[0050] Operate the driving device 5, open the upper mold 1, and let the continuous fiber after yarn arrangement and yarn spreading pass through the fiber yarn inlet 25 of the mold, pass out from the mold lip, and lead to the position of the traction machine. Start the traction machine to continuously pull out the continuous fiber until a yarn layer with neat arrangement and uniform yarn spreading is formed;

[0051] Step 3:

[0052] Pour the resin raw material into the extruder barrel, start the extruder, and allow the resin melt to be squeezed into the mold through the extruder discharge port (i.e., the feed port 10). The molten resin is transported to the longitudinal flow channel 15 inside the upper mold side frame and the longitudinal flow channel 14 inside the lower mold side frame. The molten resin turns and is transported to the upper mold flow channel and the lower mold flow channel through the transverse flow channel 17 inside the upper mold side frame and the transverse flow channel 16 inside the lower mold side frame. Then, it flows out through the hanger-type flow channel and is sprayed onto the continuous fiber in a laminating manner.

[0053] Step 4:

[0054] The continuous fibers impregnated with the resin melt are tensioned and rubbed by the upper impregnation rollers 19a and the lower impregnation rollers 19b. The resin melt is more evenly impregnated on the fibers, and the excess resin melt remains in the mold cavity and is prevented from flowing out of the mold by the melt stopper 26.

[0055] Step 5:

[0056] The continuous fibers impregnated with resin are pulled, shaped, and cooled to obtain continuous fiber reinforced thermoplastic composite prepreg.

[0057] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A continuous fiber reinforced thermoplastic composite prepreg melt impregnation mold, comprising an upper mold and a lower mold and a drive device for driving the upper mold to open and close, an impregnation channel formed between the upper mold and the lower mold, an upper heating device and a lower heating device respectively provided on the upper mold and the lower mold, an upper mold runner and a lower mold runner respectively provided in the upper mold and the lower mold, the upper mold runner and the lower mold runner respectively connected to a feed port, characterized in that: The upper mold is located in the impregnation channel and is provided with a plurality of upper impregnation rollers at intervals along the direction of the continuous fibers. The lower mold is located in the impregnation channel and is provided with a plurality of lower impregnation rollers at intervals along the direction of the continuous fibers. The plurality of upper impregnation rollers and the plurality of lower impregnation rollers are staggered along the direction of the continuous fibers, so that the impregnation channel forms a W-shaped impregnation channel. The upper mold and the lower mold are respectively provided with an upper mold side frame and a lower mold side frame, and the upper mold side frame and the lower mold side frame are respectively provided with an internal longitudinal flow channel of the upper mold side frame and an internal longitudinal flow channel of the lower mold side frame, respectively. The internal longitudinal flow channel of the upper mold side frame and the internal longitudinal flow channel of the lower mold side frame are respectively provided with a melt flow regulating component, one end of the internal longitudinal flow channel of the upper mold side frame and the internal longitudinal flow channel of the lower mold side frame are respectively connected to the feed port of the upper mold runner and the lower mold runner, and the other end of the internal longitudinal flow channel of the upper mold side frame and the internal longitudinal flow channel of the lower mold side frame are respectively connected to the feed port; a rotational yielding edge is provided at the tail turning portion of the upper mold side frame, and the angle α of the rotational yielding edge is 150°-165°; The protrusion lengths of the upper and lower dipping rollers are distributed from low to high along the direction of the continuous fiber, the diameters of the top arc surfaces of the upper and lower dipping rollers are distributed from small to large along the direction of the continuous fiber, and the spacing between the upper and lower dipping rollers is distributed from wide to narrow along the direction of the continuous fiber. The upper mold flow channel and the lower mold flow channel are distributed perpendicular to the direction of the continuous fiber; the discharge ports of the upper mold flow channel and the lower mold flow channel are in a constricted extrusion structure; A melt stopper for preventing melt backflow is provided on the fiber yarn inlet of the impregnation channel; and a lip gap adjustment device is provided on the upper die lip of the upper die.

2. The continuous fiber reinforced thermoplastic composite material prepreg melt impregnation mold according to claim 1, characterized in that: A plurality of upper dipping rollers and a plurality of lower dipping rollers are respectively mounted on the upper die and the lower die through detachable connecting pieces.

3. The continuous fiber reinforced thermoplastic composite material prepreg melt impregnation mold according to claim 1, characterized in that: The feed port is arranged on the material dividing component, and the material dividing component is provided with an upper material dividing port and a lower material dividing port which are connected with the other ends of the longitudinal flow channel inside the upper mold side frame and the longitudinal flow channel inside the lower mold side frame.

4. A process for impregnating a mold using a continuous fiber reinforced thermoplastic composite prepreg melt impregnated according to claims 1-3, characterized in that: The steps include: Step 1: According to the processing temperature of the resin, close the impregnation mold in advance and heat it to the specified temperature. After keeping it for 1-2 hours, adjust the appropriate die lip gap; Step 2: Operate the drive device, open the upper mold, and let the continuous fiber after yarn arrangement and yarn spreading pass through the fiber yarn inlet of the mold, pass out from the mold lip, and lead it to the position of the traction machine. Start the traction machine to continuously pull out the continuous fiber until a yarn layer is neatly arranged and evenly spread. Step 3: Pour the resin raw material into the extruder barrel, start the extruder, let the resin melt squeeze into the mold through the feed port, transport the molten resin to the upper mold runner and the lower mold runner, and then flow out of the mold and use the laminating method to spray the resin melt onto the continuous fiber; Step 4: The continuous fiber impregnated with resin melt passes through several upper and lower impregnation rollers for tensioning and friction, so that the resin melt is more evenly impregnated on the fiber, and the excess resin melt remains in the cavity of the mold; Step 5: The continuous fibers impregnated with resin are pulled, shaped, and cooled to obtain continuous fiber reinforced thermoplastic composite prepreg.

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