A pultrusion device and method for preparing fiber-reinforced composite materials

Abstract

The present invention discloses a pultrusion device and method for preparing fiber-reinforced composite materials, the pultrusion device comprising: a first flow channel, the interior of which is used to place core fibers and receive a first resin to impregnate the core fibers to obtain a first prepreg; a second flow channel located outside the first flow channel, the interior of which is used to place surface fibers and receive a second resin to impregnate the surface fibers to obtain a second prepreg; an isolation section located between the first flow channel and the second flow channel, used to separate the first flow channel and the second flow channel; a molding die, used to receive the first prepreg and the second prepreg and solidify and mold them to obtain a fiber-reinforced composite material. The present invention can be used to prepare a pultruded composite material in which the surface layer and the core layer of a profile use different types of resins to achieve different functional requirements of the profile for the surface layer and the core layer.

Description

Technical Field

[0001] The invention relates to the technical field of composite material processing, and in particular to a pultrusion molding device and method for preparing a fiber-reinforced composite material. Background Art

[0002] Pultrusion is a widely used method for producing fiber-reinforced composite materials. It continuously draws fiber yarn or fiber fabric from the creel, impregnates the fiber with resin through an open resin impregnation tank or a closed injection box, and then the fiber enters a mold with a certain cross-sectional shape for heating and curing, and then is continuously pulled out of the mold by a traction device, and finally cut into the required length by an online cutting machine.

[0003] The pultrusion method is very suitable for continuous materials with a certain cross-sectional shape. At the same time, pultruded fiber-reinforced composite materials have the characteristics of high fiber content, simple and efficient process, continuous production and uniform quality, and are increasingly widely used.

[0004] In the actual use of pultruded profiles, in addition to the basic mechanical properties of the material, there are often more stringent requirements for the durability of the material, especially the UV resistance of the surface layer. However, the traditional pultrusion equipment injection box can only use one resin, which makes it difficult for the traditional pultrusion process to meet the requirements of using resins with different properties for the core and surface of the profile section. This results in the surface UV resistance requirement often needing to be achieved through the surface coating process after the profile is prepared, which leads to an increase in the preparation process of composite materials and a significant increase in costs.

[0005] In order to solve the above problems, the relevant patent documents CN109016565A and US20090023870A1 provide two different implementation methods, but both methods have certain shortcomings.

[0006] Among them, US20090023870A1 provides a method in which the inner layer is first impregnated and extruded, and then the outer fiber layer and the inner pre-impregnated body are simultaneously impregnated for a second time. When this method is used, during the second preforming process, the two layers of resin will have different reflux resistances due to factors such as viscosity, causing the part with large reflux resistance to flow toward the part with small reflux resistance, and this uncontrollable flow will cause uncontrollable mixing of the two resin phases, making it difficult for the resulting product to meet the expected requirements.

[0007] Based on the technology described in US20090023870A1, CN109016565A provides a method in which the inner layer is first infiltrated and cured and then the second layer is compounded. Curing is the process in which the inner layer resin loses its fluidity, which can effectively avoid the problem of mixing the two resins. However, there are major problems with the operability of this process. The main reason is that after the inner layer resin is infiltrated and cured, the inner layer material that has just been ejected from the mold has a very high temperature, which can easily cause the surface layer resin to cure immediately after contacting it. At the same time, since the inner layer material goes through the process of ejecting from the mold and re-entering the mold, this process can easily cause mechanical damage to the first cured part. The above problems will cause difficulties in the practical application of this process. Summary of the invention

[0008] In view of this, the main purpose of the present invention is to provide a pultrusion molding device and method for preparing fiber-reinforced composite materials, which is used to prepare pultruded composite materials in which the surface layer and core layer of the profile are made of different types of resins to achieve different functional requirements of the profile for the surface layer and the core layer.

[0009] To achieve the above-mentioned object of the invention, the first aspect of the present invention provides a pultrusion molding device for preparing a fiber-reinforced composite material, comprising:

[0010] A first flow channel, the interior of which is used to place the core layer fiber and receive the first resin to impregnate the core layer fiber to obtain a first pre-impregnation body;

[0011] A second flow channel located outside the first flow channel, the interior of which is used to place surface fibers and receive a second resin to impregnate the surface fibers to obtain a second pre-impregnated body;

[0012] an isolation section located between the first flow channel and the second flow channel, used to separate the first flow channel from the second flow channel;

[0013] The molding die is used to receive the first prepreg and the second prepreg and solidify them to obtain a fiber-reinforced composite material.

[0014] In a preferred embodiment, along the direction of fiber movement in the pultrusion process, the first flow channel includes a front section with unequal cross-sectional areas and a rear section with equal cross-sectional areas connected to the front section, and the cross-sectional area of ​​one end of the front section that is not connected to the rear section is larger than the cross-sectional area of ​​the rear section.

[0015] In a preferred embodiment, the second flow channel is a flow channel with a constant cross-sectional area.

[0016] In a preferred embodiment, a first resin injection port is provided at an end of the front section that is not connected to the rear section; and / or a second resin injection port is provided in the middle section of the second flow channel.

[0017] In a preferred embodiment, along a direction perpendicular to the movement of the fibers in the pultrusion process, the second flow channel includes at least one upper second flow channel and at least one lower second flow channel, an upper isolation section is provided between the upper second flow channel and the first flow channel, and a lower isolation section is provided between the lower second flow channel and the first flow channel.

[0018] In a preferred embodiment, the second flow channel is inclined along the direction of fiber movement and gradually approaches the first flow channel, so as to allow the first prepreg and the second prepreg to merge in the molding die.

[0019] A second aspect of the present invention provides a pultrusion method for preparing a fiber-reinforced composite material, the method comprising:

[0020] Placing the core layer fiber into the first flow channel and injecting the first resin into the first flow channel to impregnate the core layer fiber to obtain a first pre-impregnation body;

[0021] Placing the surface fibers into the second flow channel and injecting a second resin into the second flow channel to impregnate the surface fibers to obtain a second pre-impregnated body;

[0022] The first prepreg and the second prepreg enter a molding die and are cured to obtain a fiber-reinforced composite material.

[0023] In a preferred embodiment, by controlling the resin flow rate entering through the first resin injection port and the resin flow rate entering through the second resin injection port, the resin pressure is made consistent when the first prepreg and the second prepreg merge.

[0024] In a preferred embodiment, 100% to 120% of the theoretically calculated required amount of resin is injected into the first resin, and preferably 102% to 110% of the first resin is injected.

[0025] According to theoretical calculation, 96% to 105% of the required amount of resin is injected into the second resin, and the preferred amount of the injected second resin is 99% to 102%.

[0026] In a preferred embodiment, the content of the first flow channel core layer fiber and the second flow channel surface layer fiber is controlled to be 50% vol. to 72% vol.

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] According to the present invention, the core fiber is placed in the first flow channel and the first resin is injected into the first flow channel to impregnate and preform the core fiber to obtain the first prepreg; the surface fiber is placed in the second flow channel and the second resin is injected into the second flow channel to impregnate and preform the surface fiber to obtain the second prepreg; the first prepreg and the second prepreg enter the molding die, and the fiber-reinforced composite material is obtained through curing molding. Since the second flow channel is arranged adjacent to the first flow channel, the second prepreg containing the surface fiber at the flow channel outlet can be completely wrapped around the periphery of the first prepreg containing the core fiber, that is, the core layer and the surface layer of the profile are obtained at the same time. In addition, there is an isolation section between the first flow channel and the second flow channel to separate the two, which can ensure that the resin on the interface of the first prepreg and the second prepreg will not flow to promote the mixing of the two phases before mixing, and the surface pressure of the first prepreg and the surface pressure of the second prepreg can be consistent or nearly consistent, and the cross-sectional shape of the flow channel will no longer change after being synthesized into a whole to ensure that no systematic backflow occurs. In addition, by setting the cross-sectional area of ​​the first flow channel outlet and the second flow channel outlet, the shape of the first prepreg can be completely consistent with the cross-sectional shape of the core layer in the product, and the shape of the second prepreg can be completely consistent with the cross-sectional shape of the surface layer in the product.

[0029] Therefore, the present invention can prepare a pultruded composite material in which the profile surface layer and the core layer adopt different types of resins, so as to achieve different functional requirements of the profile for the surface layer and the core layer.

[0030] Other features and advantages of the present invention will be described in detail through the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention but do not constitute a limitation of the present invention. In the accompanying drawings:

[0032] Figure 1 The figure is a schematic structural diagram of a resin molding device according to an example of the present invention. DETAILED DESCRIPTION

[0033] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0034] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions.

[0035] Unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] See also Figure 1 The present invention provides a pultrusion device for preparing a fiber-reinforced composite material, comprising:

[0037] A first flow channel, the interior of which is used to place the core layer fiber and receive the first resin to impregnate the core layer fiber to obtain a first pre-impregnation body;

[0038] A second flow channel located outside the first flow channel, the interior of which is used to place surface fibers and receive a second resin to impregnate the surface fibers to obtain a second pre-impregnated body;

[0039] an isolation section located between the first flow channel and the second flow channel, used to separate the first flow channel from the second flow channel;

[0040] The molding die is used to receive the first prepreg and the second prepreg and solidify them to obtain a fiber-reinforced composite material.

[0041] The first flow channel and the second flow channel are not connected to each other, so as to ensure that the first flow channel and the second flow channel are not mixed during the infiltration and respective preforming processes.

[0042] Preferably, the specific structure of the isolation section is not limited in shape, and only needs to separate the first flow channel and the second flow channel and be arranged to adapt to the shapes of the two. In a specific example, a cavity structure can be adopted.

[0043] Preferably, along the direction of fiber movement in the pultrusion process, the first flow channel includes a front section with unequal cross-sectional areas and a rear section with equal cross-sectional areas connected to the front section, and the cross-sectional area of ​​one end of the front section that is not connected to the rear section is larger than the cross-sectional area of ​​the rear section. Such an arrangement can have the effect of reducing the resin pressure in the first flow channel at the junction of the first flow channel and the second flow channel.

[0044] Preferably, the second flow channel is a flow channel of equal cross-sectional area, and such arrangement, in combination with the cross-sectional area of ​​the first flow channel, can have the effect of controlling the resin pressure in the second flow channel at the confluence position of the first flow channel and the second flow channel through the resin injection flow rate of the second flow channel.

[0045] Preferably, a first resin injection port is provided at the end where the front section and the rear section are not connected, for example Figure 1 At the left end shown, a first prepreg outlet is provided at the end where the rear section is not connected to the front section, for example Figure 1 right end shown.

[0046] Preferably, a second resin injection port is provided in the middle section of the second flow channel. For example, the second resin injection port can be provided in the middle of the second flow channel, and the distance from the starting point and the end point of the second flow channel is equal. Such a setting can ensure that the resin is fully infiltrated with the resin and is not easy to flow out from the flow channel inlet.

[0047] Preferably, along the direction perpendicular to the movement of the fibers in the pultrusion process, the second flow channel includes at least one upper second flow channel and at least one lower second flow channel, an upper isolation section is provided between the upper second flow channel and the first flow channel, and a lower isolation section is provided between the lower second flow channel and the first flow channel. In other examples, in order to completely wrap the first prepreg with the second prepreg, the second flow channel can be divided into two or more parts at its inlet, that is, it can be provided with multiple second flow channels at the top and bottom, and these parts merge into a whole at the outlet of the second flow channel. When the second flow channel is divided into multiple parts, the parts are connected to each other at the second resin injection port through an additional loop to achieve the balance of the pressure of the second prepreg in the second flow channel.

[0048] The second flow channel is arranged obliquely along the direction of fiber movement and gradually approaches the first flow channel, so as to allow the first prepreg and the second prepreg to merge in the forming mold.

[0049] Preferably, the cross-sectional shape of the rear section of the first flow channel is the same as the cross-sectional shape of the core layer in the final product, and the cross-sectional shape of the second flow channel is the same as the cross-sectional shape of the surface layer in the final product, so that after the first prepreg and the second prepreg are combined, they directly enter the molding die with unchanged cross-sectional shape for heating, so as to achieve the effect of simultaneous curing into one body. The present invention does not limit the process operation in the molding die, and a conventional resin material molding process can be used.

[0050] A second aspect of the present invention provides a pultrusion method for preparing a fiber-reinforced composite material, the method comprising:

[0051] Placing the core layer fiber into the first flow channel and injecting the first resin into the first flow channel to impregnate the core layer fiber to obtain a first pre-impregnation body;

[0052] Placing the surface fibers into the second flow channel and injecting a second resin into the second flow channel to impregnate the surface fibers to obtain a second pre-impregnated body;

[0053] The first prepreg and the second prepreg enter a molding die and are cured to obtain a fiber-reinforced composite material.

[0054] The method of the present invention further comprises: controlling the resin flow rate entering the first resin injection port and the resin flow rate entering the second resin injection port to achieve the same pressure when the first prepreg and the second prepreg meet. The "same pressure" mentioned herein means that the pressure is equal or nearly equal.

[0055] As for the first flow channel in the device described above, the pressure at the first resin injection port is consistent with the liquid pressure in the inlet cross section, that is, the atmospheric pressure, while the liquid pressure at the outlet of the first flow channel is determined by the pressure drop along the box formed during the pultrusion process. The pressure in the first flow channel is affected by the viscosity of the glue, the cross-sectional shape and the pultrusion rate, and is not adjustable. As for the second flow channel in the device described above, when the pressure drop along the second flow channel is constant, the pressure at the outlet of the second flow channel is equal to the pressure of the glue at the inlet of the second resin plus the pressure drop along the second flow channel. Therefore, as long as the pressure at the second resin injection port can be controlled, the resin pressure at the outlet of the second flow channel, that is, the pressure of the second pre-impregnated body at the outlet of the second flow channel, can be adjusted to achieve the purpose of adjustable pressure at the outlet of the second flow channel. Due to the cross-sectional characteristics of the second flow channel, it will not cause leakage in other parts except the outlet of the second flow channel. Therefore, in a specific example, the purpose of pressure balance can also be achieved by controlling the flow control of the resin entering the second resin injection port.

[0056] In a specific example, it is preferred to use a high-pressure glue injection device to inject the first resin or the second resin.

[0057] Preferably, 100% to 120% of the theoretically calculated required amount of resin is injected into the first resin, and preferably 102% to 110% of the injected first resin is injected.

[0058] Preferably, 96% to 105% of the theoretically calculated required amount of resin is injected into the second resin, and the preferred amount of the injected second resin is 99% to 102%.

[0059] In the actual production process, it can be adjusted according to the actual situation of the cross section of the product. When the interface of the two layers of resin invades the surface layer (the core layer resin enters the surface layer), the injection amount of the second resin of the surface layer can be increased, otherwise the injection amount of the second resin of the surface layer can be reduced. The injection amount of the first resin of the core layer is preferably to minimize the waste of the core layer backflow resin while ensuring sufficient first resin.

[0060] In the present invention, the fiber contents of the core layer and the surface layer in the final product can be calculated and set according to their respective proportions, and the fibers are inserted into the respective flow channels. Preferably, the fiber contents of the first flow channel and the second flow channel are controlled to be 50% vol. to 72% vol.

[0061] During the pultrusion process, the core fibers are penetrated into the first flow channel, the surface fibers are penetrated into the second flow channel, the first resin or the second resin glue is injected into the first flow channel or the second flow channel to wet the core fibers or the surface fibers therein, and the resin enters the molding die along with the movement of the fibers, and the profile is prepared by curing the resin. In the present invention, the change in resin pressure is caused by the change in the amount of the resin glue moving with the fibers when the cross section of the first flow channel or the second flow channel changes due to the fibers driving the resin glue.

[0062] The final product formed by the method of the present invention usually does not need to be subjected to subsequent decorative treatment, so the decorativeness of the profile and the problem of fiber breakage and piercing of the uncoated pultruded profile are also solved in the process of the present invention.

[0063] The surface layer of the final product formed by the method of the present invention is both a protective functional layer and a decorative layer. In order to improve the decorative effect of the surface layer, the decorative effect can be achieved by coloring the second resin and selecting a fabric with a specific decorative texture.

[0064] In the present invention, the core fiber and / or the surface fiber are one or more selected from the following: glass fiber, carbon fiber, polyester fiber, natural fiber, aromatic polyamide fiber, nylon fiber, basalt fiber, boron fiber, silicon carbide fiber, asbestos fiber, whisker and metal fiber, and / or felt, fabric, etc. composed thereof.

[0065] The first resin is one or more selected from the group consisting of aromatic polyurethane, epoxy resin, unsaturated resin, aliphatic polyurethane and vinyl resin.

[0066] The second resin is one or more selected from the group consisting of aromatic polyurethane, epoxy resin, unsaturated resin, aliphatic polyurethane, vinyl resin, phenolic resin and the above resins containing flame retardant and / or UV stabilizer.

[0067] When the core layer fiber is made of inorganic fiber such as glass fiber, the broken short fibers remaining on the surface may cause irritation during use. To solve this problem, the surface fiber should not be made of inorganic fiber such as glass fiber. It is preferred to use chemical fiber fabrics such as polyester and nylon, which will not produce irritating broken fibers and can effectively prevent the broken fibers in the core layer from protruding from the surface.

[0068] The present invention is further described below with detailed exemplary embodiments, but these embodiments do not constitute any limitation to the present invention.

[0069] Example 1

[0070] See also Figure 1 The embodiment of the present invention provides a pultrusion device for preparing a fiber-reinforced composite material, comprising:

[0071] A first flow channel 10, the interior of which is used to place the core layer fiber and receive the first resin to impregnate the core layer fiber to obtain a first pre-impregnation body;

[0072] A second flow channel 20 located outside the first flow channel 10, the interior of which is used to place surface fibers and receive a second resin to impregnate the surface fibers to obtain a second pre-impregnated body;

[0073] An isolation section 30 located between the first flow channel 10 and the second flow channel 20, used to separate the first flow channel 10 from the second flow channel 20;

[0074] The molding die 40 is used to receive the first prepreg and the second prepreg and solidify them to obtain a fiber-reinforced composite material.

[0075] Along the direction of fiber movement in the pultrusion process, the first flow channel 10 includes a front section 11 of unequal cross-sectional area and a rear section 12 of equal cross-sectional area connected to the front section 11, the cross-sectional area of ​​the front section 11 is greater than or equal to the cross-sectional area of ​​the rear section 12, and the cross-sectional area of ​​the left end of the front section 11 is greater than the cross-sectional area of ​​the rear section 12, and gradually decreases along the direction of the first resin flow to be close to the cross-sectional area of ​​the rear section 12. The first resin injection port 13 is located at the flow channel inlet at the left end of the front section 11, and the first flow channel outlet 14 located at the rear section 12 is connected to the inlet of the molding die 40.

[0076] The second flow channel 20 is a flow channel with a constant cross-sectional area. A second resin injection port 21 is arranged in the middle of the second flow channel 20, and the distance from the second resin injection port 21 to the left end starting point and the right end end of the second flow channel is equal.

[0077] The second flow channel 20 is arranged obliquely along the direction of fiber movement and gradually approaches the first flow channel 10, so as to allow the first prepreg and the second prepreg to merge in the molding die.

[0078] The cross-sectional shape of the rear section 12 of the first flow channel is the same as the cross-sectional shape of the core layer in the final product, and the cross-sectional shape of the second flow channel 20 is the same as the cross-sectional shape of the surface layer in the final product. As a result, after the first prepreg and the second prepreg are combined, they directly enter the molding mold 40 with unchanged cross-sectional shape for heating, so as to achieve the effect of simultaneous solidification into one.

[0079] This embodiment is to realize a product with an outer dimension of 50 mm×40 mm and a profile wall thickness of 3 mm, wherein the core layer is an aromatic polyurethane resin (a first resin) and the surface layer is an aliphatic polyurethane resin (a second resin, with a surface thickness of 0.2 mm). The pultrusion molding method comprises:

[0080] Placing the core layer fiber into the first flow channel (the amount of the core layer fiber is 62% vol.) and injecting the first resin into the first flow channel to impregnate the core layer fiber to obtain a first pre-impregnated body;

[0081] Placing the surface fibers into the second flow channel (the amount of the surface fibers is 58% vol.) and injecting the second resin into the second flow channel to wet the surface fibers, thereby obtaining a second pre-impregnated body;

[0082] The first prepreg and the second prepreg enter a molding die and are cured to obtain a fiber-reinforced composite material.

[0083] Among them, the size of the iron first flow channel 10 is 44mm×34mm, the front section 11 flow channel gradually transitions from a 60mm×50mm square to 49.6mm×39.6mm along the oblique line, and when the size reaches 49.6mm×39.6mm, the rear section 12 flow channel is a straight flow channel of equal cross-section of 49.6mm×39.6mm until the inlet of the molding mold.

[0084] The second flow channel is a rectangle with equal cross-section, and the injection amount of the second resin is set to 12g / min. The pultrusion rate is 0.8m / min. The pultrusion rate is the rate at which the tractor drives the fiber to move, and the power of the pultrusion system is the tractor. The injection amount of the resin is the value calculated by the set traction rate, and the theoretical speed corresponds to the theoretical resin consumption.

[0085] The core layer fiber is 4800TEX glass fiber with 165 strands, and the surface layer fiber is polyester cloth with a surface density of 160g. The surface layer thickness of the product obtained in this embodiment is 0.2mm, and there is a slight trace of mixing of the surface layer resin and the core layer resin at the intersection of the two layers near the core layer.

[0086] Example 2

[0087] Similar to Example 1, the difference is that the second resin injection port 21 is located at the connection position between the front section and the rear section of the second flow channel, which corresponds to the connection between the front section and the rear section of the first flow channel, that is, consistent in the vertical direction.

[0088] This embodiment is to realize a product with an outer dimension of 50mm×40mm and a profile wall thickness of 3mm, the core layer is epoxy resin, the surface layer is aliphatic polyurethane resin, and the surface layer thickness is 0.5mm;

[0089] The fiber content of the core layer of the first flow channel is 55% vol., and the fiber content of the surface layer of the second flow channel is 65% vol.

[0090] The injection amount of the second resin was set to 35 g / min and the pultrusion rate was 0.8 m / min.

[0091] The core layer fiber uses 4800TEX glass fiber with 130 strands, and the surface layer fiber uses 2400TEX glass fiber with 60 strands. The surface thickness of the product obtained in this embodiment is 0.5mm, and there are slight traces of surface resin and core resin mixing at the surface position of the two layers.

[0092] Obviously, the above embodiments of the present invention are merely examples for clearly explaining the present invention, and are not intended to limit the implementation methods of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is impossible to list all implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are within the spirit scope of the present invention.

Claims

1. A pultrusion device for preparing a fiber-reinforced composite material, characterized in that: include: A first flow channel, the interior of which is used to place the core layer fiber and receive the first resin to impregnate the core layer fiber to obtain a first pre-impregnation body; A second flow channel located outside the first flow channel, the interior of which is used to place surface fibers and receive a second resin to impregnate the surface fibers to obtain a second pre-impregnated body; an isolation section located between the first flow channel and the second flow channel, used to separate the first flow channel from the second flow channel; A molding die, used for receiving the first prepreg and the second prepreg and curing them to obtain a fiber-reinforced composite material; Along the direction of fiber movement in the pultrusion process, the first flow channel includes a front section with unequal cross-sectional areas and a rear section connected to the front section and with equal cross-sectional areas, and the cross-sectional area of ​​one end of the front section that is not connected to the rear section is larger than the cross-sectional area of ​​the rear section; The second flow channel is a flow channel with a constant cross-sectional area; A first resin injection port is provided at one end of the front section and the rear section which are not connected; a second resin injection port is provided in the middle section of the second flow channel; The second flow channel is arranged obliquely along the direction of fiber movement and gradually approaches the first flow channel, so as to allow the first prepreg and the second prepreg to merge in the forming mold.

2. The pultrusion device according to claim 1, characterized in that: Along a direction perpendicular to the movement of the fibers in the pultrusion process, the second flow channel includes at least one upper second flow channel and at least one lower second flow channel, an upper isolation section is provided between the upper second flow channel and the first flow channel, and a lower isolation section is provided between the lower second flow channel and the first flow channel.

3. A pultrusion method for preparing a fiber-reinforced composite material, using the device according to any one of claims 1 to 2, characterized in that: The method includes: Placing the core layer fiber into the first flow channel and injecting the first resin into the first flow channel to impregnate the core layer fiber to obtain a first pre-impregnation body; Placing the surface fibers into the second flow channel and injecting a second resin into the second flow channel to impregnate the surface fibers to obtain a second pre-impregnated body; The first prepreg and the second prepreg enter a molding die and are cured to obtain a fiber-reinforced composite material.

4. The pultrusion method according to claim 3, characterized in that: By controlling the resin flow rate entering through the first resin injection port and the resin flow rate entering through the second resin injection port, the resin pressure can be made consistent when the first prepreg and the second prepreg are combined.

5. The pultrusion method according to claim 4, characterized in that: Injecting the first resin according to 100% to 120% of the theoretically calculated required amount of resin; The second resin is injected according to 96% to 105% of the theoretically calculated required resin amount.

6. The pultrusion method according to claim 5, characterized in that: The amount of the first resin injected is 102% to 110%; the amount of the second resin injected is 99% to 102%.

7. The pultrusion method according to claim 4, characterized in that: The content of the first flow channel core layer fiber and the second flow channel surface layer fiber is controlled to be 50% vol. to 72% vol.

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