Manufacturing process for a fiber-reinforced resin molded product

Abstract

Manufacturing process for a fiber-reinforced resin molded product comprising the impregnation of a fiber layer (12) with resin, wherein the manufacturing process comprises: installing (S11) a preform (10) having at least a lining (11) and a fiber layer (12) in the mold (20) and evacuating the mold (20); supplying (S12) a specified quantity of a first resin composition to the fiber layer (12) and stopping the supply of the first resin composition when the specified quantity is reached; transitioning (S13) to a relief state after the supply of the first resin composition has been stopped in order to move an upper mold (21) and a lower mold (22) so that they are slightly separated from each other, thereby relieving a force for pressing the preform (10); starting (S14) the supply of a second resin composition to the fiber layer (12);Switching (S15) to a fixed state during the supply of the second resin composition in order to move the upper mold (21) and the mold (22) so that they are close together, thereby increasing pressure on the second resin composition; stopping (S16) the supply of the second resin composition and allowing the second resin composition to cure; and releasing (S17) the resin-impregnated preform (10) from the mold (20); wherein a curing start temperature of the first resin composition is higher than a curing start temperature of the second resin composition, and wherein the first resin composition is supplied such that it reaches an outer circumferential region of the fiber layer (12) of the preform (10) installed in the mold (20) and is further impregnated until it reaches an innermost layer face of the fiber layer (12).

Description

BACKGROUND OF THE INVENTION1. Field of the InventionThe present invention relates to a method for producing a molded product (fiber-reinforced resin molded product) reinforced by a fiber layer impregnated with resin.2. Description of the Prior ArtFor example, a high-pressure tank for a fuel cell vehicle has a liner forming an inner space of the high-pressure tank, and high strength is realized by disposing a resin-impregnated fiber layer on the outer periphery of the liner. Further, not limited to the high pressure tank for the fuel cell vehicle, a resin-impregnated fiber layer may be disposed to realize high strength.Japanese Patent Application JP 2019-056 415 A discloses a method for manufacturing a high-pressure tank, in which a parison having a fiber layer formed on an outer surface of a liner forming an inner space of the high-pressure tank is placed in a mold, and the fiber layer is impregnated with resin by rotating the parison in the mold with the central axis of the parison as a rotation center while injecting resin toward the parison placed in the mold. DE 10 2011 012 900 A1 discloses a method for producing a fiber-reinforced plastic composite component, in which a fiber arrangement is inserted into the cavity of an RTM tool, a first matrix material is injected into the cavity at a first location, and the fiber arrangement is impregnated with the first matrix material in a first component region. Furthermore, a second matrix material is injected into the cavity at a second location and the fiber arrangement is impregnated with the second matrix material in a second component region. In this case, the first and second matrix materials flow into one another in the boundary zone between the first and second component regions, wherein a mixture is formed and the first matrix material, the second matrix material and the mixture of first and second matrix materials are cured. Regarding the prior art, reference is also made to WO 2008 / 119 942 A1, DE 10 2005 008 252 A1 and DE 10 2015 000 947 A1, from which the production of an article with resin-impregnated fibers is generally known.SUMMARY OF THE INVENTIONWhen impregnating the fiber layer with resin, it may be difficult to uniformly impregnate the resin depending on the thickness and shape of the layer. When resin is injected at high pressure, the pressure causes deformation of the object to be molded, or the equipment becomes large-area. In addition, it cannot be said that sufficient impregnation is possible even if the fiber layer is twisted during impregnation. In particular, since the high pressure tank for a fuel cell vehicle has a thick fiber layer to ensure strength and the shape is a cylindrical shape long in the axial direction, the above problem is more pronounced.In contrast, the above problem can be alleviated by taking time to impregnate and cure the fiber layer by adjusting the temperature, for example, but there is a problem in that productivity is lowered. Further, when a quick setting resin is impregnated with a high pressure to increase productivity, a large-area apparatus as described above may be required or the molded product may be deformed.Based on the above-described problems of the related art, an object of the present invention is to provide a manufacturing method of a fiber-reinforced resin molded product in which a fiber layer having high quality can be impregnated while suppressing a decrease in productivity. This object is achieved with the production method according to claim 1, advantageous developments of the width being the subject matter of the dependent claims.An aspect of the present invention is a manufacturing method for a fiber-reinforced resin molded product, which includes impregnating a fiber layer with resin, the manufacturing method including: installing a preform having at least a liner and a fiber layer in the mold and evacuating the mold; supplying a predetermined supply amount of a first resin composition to the fiber layer and stopping the supply of the first resin composition when the predetermined supply amount is reached; changing to a relief state after the supply of the first resin composition is stopped to move an upper mold and a lower mold so as to be slightly separated from each other, thereby relaxing a force for pressing the preform; starting the supply of a second resin composition to the fiber layer; Changing to a fastened state during the supply of the second resin composition to move the upper mold and the mold to be close to each other, thereby increasing a pressure on the second resin composition; stopping the supply of the second resin composition and allowing the second resin composition to cure; and releasing the resin-impregnated preform from the mold, wherein a curing start temperature of the first resin composition is higher than a curing start temperature of the second resin composition, and the first resin composition is supplied to reach an outer peripheral portion of the fiber layer of the preform installed in the mold and is further impregnated until it reaches an innermost layer side of the fiber layer. Here, the "curing start temperature" means the temperature at which the polymerization reaction starts and a rapid temperature rise occurs.A mold may be used for impregnating the fiber layer with the resin, and the temperature of the mold may be set lower than the curing start temperature of the first resin composition and higher than the curing start temperature of the second resin composition.The supply amount of the first resin composition may be 50% by mass or more and 67% by mass or less with respect to a total supply amount of the first resin composition and the second resin composition.In each of the first resin composition and the second resin composition, curing may be started by mixing a main agent and a curing agent, and the main agent of the first resin composition and the second resin composition may be the same material.According to the manufacturing method of a fiber-reinforced molded product of the present invention, when a fiber layer is impregnated with resin, the fiber layer can be impregnated with a high quality while suppressing a decrease in productivity.BRIEF DESCRIPTION OF THE DRAWINGSThe features and advantages, and technical and economic significance of exemplary embodiments of the invention will be described below with reference to the accompanying drawings, in which like reference numerals designate like elements, and wherein: FIG. 1A is an exploded view showing a mold 20 and a preform 10; FIG. 1B shows a combination of the mold 20 and the preform 10; FIG. 2 is a diagram illustrating the configuration and relationship among an impregnating apparatus 30, the mold 20 and the parison 10; FIG. 3 is a diagram illustrating the flow of a fiber-reinforced resin molded product manufacturing method S 10; FIG. 4 is a diagram illustrating a step S 11 of installing in a mold and venting; FIG. 5 is a diagram illustrating a step S 12 of starting and stopping a primary injection; FIG. 6 is a diagram illustrating a step S 13 of changing to a relief state; FIG. 7 is a diagram illustrating a step S 14 of starting secondary injection; and FIG. 8 is a diagram illustrating a step S 15 of changing to a mounted state.DETAILED DESCRIPTION OF EMBODIMENTSProduction Equipment for Fiber-Reinforced Resin Molded ProductIn FIGS. 1A and 1B, the parison 10, which is a molded article, and the mold 20 for impregnating the resin into the parison 10 are schematically illustrated. In FIGS. 1A and 1B, the mold 20 is represented by a cross section, the parison 10 is represented by a surface instead of a cross section, and an inner mold thereof is represented by a broken line. FIG. 1A is an exploded view of the mold 20 and the parison 10. FIG. 1B is a diagram showing a state in which the parison 10 is installed in the mold 20. FIG. 2 schematically shows an apparatus for impregnation (impregnating apparatus 30). As will be apparent from the following description, the present invention relates to a fiber-reinforced resin molded product of a so-called resin transfer molding (RTM) in which a fiber layer provided in a parison is impregnated with a resin composition and then cured to form a reinforcing layer.Preform preformThe parison 10 is an intermediate member that finally becomes a high-pressure tank, which is an aspect of the fiber-reinforced resin molded product, and is configured to include at least a liner 11 and a fiber layer 12. With respect to high-pressure tanks, the present embodiment is a high-pressure tank for fuel cell vehicles.The liner 11 is a hollow member defining the interior of the high-pressure tank. The liner may be made of a material that can hold what is contained in the internal space without being leaky, and a known material may be used. For example, nylon resin, polyethylene-based resin, or metal such as stainless steel.The fiber layer 12 is a layer in which fibers are wound around the outer surface of the liner 11 in multiple layers to a predetermined thickness. The thickness of the fiber layer 12 is determined by the required strength and is not particularly limited, but is set to a thickness of about 10 mm to 30 mm. Particularly, in a high pressure tank for a fuel cell vehicle, it is necessary to form a thick fiber layer in order to secure strength, which is very difficult from the viewpoint of impregnating the fiber layer with resin. In the fiber layers, the side of the liner 11 may be referred to as "inner layer side", and the side opposite to the liner 11 may be referred to as "outer layer side". Carbon fibers are used as the fibers. More specifically, the fibers are a carbon fiber bundle having a strip shape in which the carbon fibers form a bundle having a predetermined cross-sectional shape (e.g., a rectangular cross-section). The fiber layer is formed by winding such a carbon fiber bundle around the outer surface of the liner. The winding of the fibers (bundles) around the outer surface of the liner 11 is performed by, for example, a filament winding method or the like.The fiber layer 12 of such a preform 10 is impregnated with resin. Further, if necessary, a protective layer of glass fibers is formed on the outer periphery thereof to form a high pressure tank.MoldThe mold 20 is a mold for impregnating the fiber layer 12 of the preform 10 with resin, and is configured to have an upper mold 21 and a lower mold 22 in the present embodiment. By overlapping the upper mold 21 and the lower mold 22, an inner space following the shape of the preform 10 is formed inside the mold 20. This internal space can be evacuated and can form a sealed space.Further, the upper mold 21 may move relative to the lower mold 22, as shown by a straight arrow in FIG. 1B. Thus, not only can the preform 10 be installed on the mold 20 and separated from the mold 20, but the upper mold can also be moved to apply pressure to the preform 10 and moved to relieve the applied pressure. More specifically, the mold 20 may be in an open state, a fastened state, and a relief state as follows. The open state is a state in which the upper mold 21 is completely separated from the lower mold 22 and the upper surface of the lower mold 22 is completely exposed and opened (not illustrated). In this state, the preform 10 is installed on the lower mold 22, and the preform 10 is released from the mold 20 after impregnation. The fixed state is a state in which the preform 10 is installed in the mold 20 and the upper mold 21 and the lower mold 22 are completely connected and fixed (see FIGS. 1B and 4 ). Also in this fixed state, it is preferable that a slight gap is formed between the fiber layer 12 of the preform 10 before impregnation and the surfaces of the upper mold 21 and the lower mold 22. This gap takes into account that the volume of the fiber layer 12 after impregnation due to impregnation of the resin composition becomes larger than the volume before impregnation. This gap between the upper mold 21 and the parison 10 is the same as the gap between the lower mold 22 and the parison 10, and the relief state is a state in which the parison 10 is installed in the mold 20 and the upper mold 21 and the lower mold 22 are separated from each other slightly more than in the fixed state (see FIG. 6 ). The unloading state is achieved, for example, by slightly raising the upper mold 21 from the fixed state. At this time, the gap between the upper mold 21 and the preform 10 is larger than the gap between the lower mold 22 and the preform 10.Further, the upper mold 21 is provided with a flow path 21a which extends from the outside to the fiber layer 12 of the installed preform 10. By passing the resin composition through the flow path 21 a, the resin composition is supplied to the fiber layer 12 and impregnated. Further, the mold 20 is provided with an air flow passage for evacuating (vacuum-venting) the formed internal space.Further, the mold 20 is configured such that the temperature can be maintained at a desired temperature by a temperature control device (not shown).Although the material used for the mold 20 is not particularly limited, a metal is preferably used as usual, and the mold 20 is a so-called metal mold.Impregnating DeviceThe impregnating device 30 is a device that supplies the resin composition to be impregnated to the mold 20 in which the preform 10 is installed. As shown in FIG. 2, the impregnating apparatus 30 of the present embodiment includes a main agent tank 31, a main agent pump 32, a first curing agent tank 33, a second curing agent tank 34, a switching valve 35, a curing agent pump 36, and a mixer 37.The main agent tank 31 is a tank in which the main agent of the composition to be impregnated is stored. The main means will be described later. The main agent pump 32 is a pump that delivers the main agent stored in the main agent tank 31 to the mixer 37. That is, the main agent tank 31 and the pump 32 are connected by a piping, and the main agent pump 32 and the mixer 37 are connected by a piping.The first curing agent tank 33 is a tank in which the first curing agent is stored, and the second curing agent tank 34 is a tank in which the second curing agent is stored. The individual curing agents will be described later. The switching valve 35 is connected to the first hardening agent tank 33, the second hardening agent tank 34, and the hardening agent pump 36, and is configured to be able to switch the type of the hardening agent supplied from the hardening agent pump 36 to the mixer 37. Therefore, the first hardening agent tank 33 and the switching valve 35 are connected by a piping, the second hardening agent tank 34 and the switching valve 35 are connected by a piping, and the switching valve 35 and the hardening agent pump are connected by a piping. The hardening agent pump 36 and the mixer 37 are connected by a piping.The mixer 37 is a device that mixes the supplied main agent and the curing agent and supplies the resin composition formed by mixing into the mold 20. Specifically, the mixer 37 is connected to the flow path 21 aof the mold 20 (see FIGS. 1A and 1B ) through a piping, and the supplied resin composition passes through the piping and enters the flow path 21 aof the mold 20.Production Method of Fiber-Reinforced Resin Molded ProductNext, a method for producing a fiber-reinforced resin molded product will be described. Here, for the sake of convenience, a high pressure tank is given as a preferable example of the fiber-reinforced resin molded product, and the mold and the impregnating apparatus will be described with reference to the mold 20 and the impregnating apparatus 30. However, the present invention is not limited to the use of the mold 20 and the impregnating apparatus 30.FIG. 3 shows the flow of a manufacturing method S 10 for a fiber-reinforced resin molded product according to an example. As shown in FIG. 3, the fiber-reinforced resin molded product manufacturing method S 10 according to the present embodiment includes an in-mold installation and venting step S 11, a primary injection starting and stopping step S 12, a relief state switching step S 13, a secondary injection starting step S 14, a fixed state switching step S 15, a secondary injection stopping step S 16, and a product removing step S 17 from the mold. Each step will be described below.Step S 11 of Installation in Mold and VentingIn the in-mold installation and venting step S 11 (may be referred to as "step S 11"), as shown in FIG. 4, the parison 10 is installed in the mold 20 and vented by evacuation. By this venting, the impregnated resin composition can easily penetrate into the fiber layer 12, and the impregnation is more smoothly performed.More specifically, in the present embodiment, the mold 20 is in the open state, and the parison 10 is installed on the lower mold 22 with the upper surface largely exposed, and then the upper mold 21 is disposed so as to cover the lower mold 22 and the parison 10 installed on the lower mold 22 to be in the fixed state. Then, the vacuum venting is performed by a vacuum pump. The vacuum venting is completed before a first resin composition is supplied to the fiber layer 12, which is performed in the next step.Step S 12 of starting and stopping the primary injectionIn step S 12 of starting and stopping the primary injection (may be referred to as "step S 12"), the first resin composition in which the main agent and the first curing agent are mixed is supplied to the fiber layer 12, and the supply is stopped thereafter.Principal AgentThe main agent is a material capable of reinforcing the fiber layer by being impregnated into the fiber layer 12 and cured, and thus a suitable material can be used. In the present embodiment, the main agent is an epoxy resin, but other examples include polyurethane resin, phenol resin and melamine resin.First Curing Agent and First Resin CompositionThe first curing agent is a material that cures the main agent by being mixed with the main agent. The first curing agent is mixed with the main agent to form the first resin composition. Thus, in the present embodiment, the first curing agent is made of a material capable of curing the epoxy resin. However, for the first curing agent, a curing agent with which the curing start temperature of the first resin composition is higher than the curing start temperature of the second resin composition described later is used, and preferably the curing start temperature of the first resin composition is higher than the temperature of the mold 20. The "curing starting temperature" as used herein means the temperature at which the polymerization reaction starts and a rapid temperature rise occurs.The kind of the first curing agent is not particularly limited as long as it may be the first resin composition satisfying the above conditions, and examples thereof are aromatic polyamines such as dicyandiamide and metaphenylenediamine.Although the supply amount of the first resin composition is not particularly limited, it is preferable that the supply amount is equal to or more than 50% by mass (mass percent) and equal to or less than 67% by mass with respect to the total amount of the first resin composition and the second resin composition. When the supply amount of the first resin composition is less than 50% by mass, there is a possibility that the amount of the first resin composition reaching the layer of the fiber layer 12 on the liner 11 side is small, and when the amount of the first resin composition is more than 67% by mass, there is a possibility that the time until curing of the outer layer to be released from the mold becomes long, which may impair productivity. The supply of the first resin composition is stopped when the set supply amount is reached.Specifically, in the present embodiment, as shown in FIG. 5, the main agent stored in the main agent tank 31 is supplied to the mixer 37 by the main agent pump 32. On the other hand, the first hardening agent stored in the first hardening agent tank 33 passes through the switching valve 35 and is supplied to the mixer 37 by the hardening agent pump 36. At this time, the switching valve 35 opens the flow path of the piping from the first curing agent tank 33 and blocks the flow path of the piping from the second curing agent tank 34. in the mixer 37, the supplied main agent and the first curing agent are mixed to form the first resin composition, and the mixer 37 supplies the prepared first resin composition to the flow path 21 aof the mold 20. The supplied first resin composition reaches the outer peripheral portion of the fiber layer 12 of the preform 10 installed in the mold 20, and is further impregnated by penetrating into the fiber layer. At this time, in the present embodiment, the temperature of the mold 20 is set lower than the curing start temperature of the first resin composition. How low the temperature is set is not particularly limited, and can be determined in consideration of the shortest time in which the first resin composition can reach the layer of the fiber layer 12 in contact with the liner 11 and the time required for curing.As described above, in this step, the temperature is adjusted and the curing agent is used so that the flowability is not lost until the first resin composition reaches the innermost layer side of the fiber layer (the layer opposite to the fiber layer from the outer layer side to which the first resin composition is supplied). As a result, even with a thick fiber layer, the resin is more securely impregnated on the inner layer side of the fiber layer. Since the high fluidity can be maintained for a long time, when the first resin composition is impregnated, the injection pressure at the time of impregnation can be kept low, whereby equipment can be reduced and the cost can be lowered.Step S 13 of Changing to Relief StateIn step S 13 of changing to the relief state (may be referred to as "step S 13"), after the primary injection is stopped in step S 12, the upper mold 21 and the lower mold 22 are moved to be slightly separated from each other, the state is changed to the relief state, the force for pressing the parison 10 is relaxed, and a slight gap is provided between the upper mold 21 and the parison 10. The size of the gap is not particularly limited, but may be about 10% of the thickness of the fiber layer. In the present embodiment, as shown by the straight arrow in FIG. 6, the upper mold 21 is raised to change the state to this unloading state.Step S 14 of Starting Secondary InjectionIn step S 14 of starting the secondary injection (may be referred to as "step S 14"), the second resin composition in which the main agent and the second curing agent are mixed is supplied to the mold 20 in the relief state.Principal AgentThe main agent is a material capable of reinforcing the fiber layer by being impregnated into the fiber layer 12 and cured, and thus a suitable material can be used. In the present embodiment, it is the same epoxy resin as the main agent of the first resin composition. By using the same as the main agent of the first resin composition and the main agent of the second resin composition, the difference in physical properties can be reduced, and thus problems in performance such as strength and delamination are less likely. However, if there is no problem with such performances, the use of another principal agent is not prevented.Second Curing Agent and Second Resin CompositionThe second curing agent is a material that cures the main agent by being mixed with the main agent. A second resin composition is obtained by mixing the second curing agent with the main agent. That is, in the present embodiment, the second curing agent is a material capable of curing the epoxy resin. However, for the second curing agent, a curing agent in which the curing start temperature of the second resin composition is lower than the curing start temperature of the first resin composition described above is used, and preferably the curing start temperature of the second resin composition is lower than the temperature of the mold 20. Here, the "curing start temperature" is as described above.The kind of the second curing agent is not particularly limited as long as it can form the second resin composition satisfying the above requirements, and examples thereof are aliphatic polyamines such as xylenediamine and diethylenetriamine.The supply amount of the second resin composition is determined by the supply amount of the first resin composition.Specifically, in the present embodiment, as shown in FIG. 7, the main agent stored in the main agent tank 31 is supplied to the mixer 37 by the main agent pump 32. On the other hand, the second hardening agent stored in the second hardening agent tank 34 passes through the switching valve 35 and is supplied to the mixer 37 by the hardening agent pump 36. At this time, the switching valve 35 opens the flow path of the piping from the second hardening agent tank 34 and blocks the flow path of the piping from the first hardening agent tank 33. in the mixer 37, the main agent and the supplied second hardening agent are mixed to form the second resin composition, and the mixer 37 supplies the prepared second resin composition to the flow path 21 aof the mold 20. The supplied second resin composition reaches the outer peripheral portion of the fiber layer 12 of the preform 10 installed in the mold 20, at which time the mold 20 is in the relief state through step S 13, the pressure on the preform 10 by the mold 20 is suppressed, and a gap is formed between the upper mold 21 and the preform 10. Thus, the resistance upon flowing the second resin composition can be suppressed. Therefore, the entire space between the upper mold 21 and the parison 10 is uniformly filled with the supplied second resin composition. In addition, in the present embodiment, the temperature of the mold 20 is set higher than the curing start temperature of the second resin composition. How high the temperature is set is not particularly limited and can be determined in consideration of the shortest time required for the second resin composition to penetrate the desired fiber layer and the time required for curing.Step S 15 of Changing to Mounted StateIn step S 15 of changing to the attached state (may be referred to as "step S 15"), the upper mold 21 and the lower mold 22 are moved to be close to each other, and the mold is brought into the attached state. Thereby, the pressure that the second resin composition receives from the mold 20 is increased, the impregnation of the second resin composition is promoted, the second resin composition that is near the outer surface of the fiber layer 12 is flattened, and the surface becomes smooth. In the present embodiment, as shown in FIG. 8, the upper mold 21 is brought closer to the lower mold 22.Step S 16 of Stopping Secondary InjectionIn step S 16 of stopping the secondary injection (may be referred to as "step S 16"), the supply of the second resin composition is stopped when the state is changed to the fixed state in step S 15, the fiber layer is sufficiently impregnated with the second resin composition, and a desired supply amount is achieved. Then, the process waits until the second resin composition is cured. In the present invention, by supplying the above-described second resin composition as a secondary injection, the curing of the outer layer side required for demolding can be promoted, and thus the productivity can be improved. Since the second resin composition is rapidly cured, the heat associated with the reaction tends to be high, and this heat can accelerate the curing of the first resin composition impregnated in advance, and the curing of the entire impregnated resin can also be accelerated.Step S 17 of DemoldingIn step S 17 of demolding (may be referred to as "step S 17"), after at least the second resin composition has been cured in step S 16 and the resin composition on the outer layer side of the fiber layer 12 has been cured, the resin-impregnated preform 10 is released from the mold 20. In the present embodiment, the upper mold 21 of the mold 20 is separated from the lower mold 22 to open the mold 20 for demolding.Effects and othersThe resin-impregnated preform 10 can be obtained by the manufacturing method including each of the above-mentioned steps, the mold for such purpose, and the impregnating apparatus. A high pressure tank may be formed by further forming a layer of resin impregnated glass fibers on the resin impregnated preform 10. According to the present invention, when the fiber layer is impregnated with resin by the RTM impregnation method, plural kinds of resin compositions having different curing start temperatures are used in sequence. Specifically, the first resin composition is used at a slower curing rate on the inner layer side, while the second resin composition is used at a faster curing rate on the outer layer side for impregnation. Thus, the first resin composition can also be impregnated with a thick fiber layer on the inner layer side, so that a corresponding impregnation takes place. On the other hand, since the second resin composition is impregnated on the outer layer side, the outer layer side can be rapidly cured and released from the mold. In addition, the heat generated when the second resin composition is cured accelerates the curing of the first resin composition. Thereby, both homogeneous impregnation and rapid curing required for demolding can be achieved, and at the same time, cost reduction by improving productivity and high performance and quality by homogeneous impregnation can be realized.In the above, for each of the first resin composition and the second resin composition, a composition is used whose curing starts by mixing a main agent and a curing agent. However, the present invention is not limited thereto, and resins cured by heating or other methods may also be used. However, since the main agent can be made of the same material by using a composition in which curing is started by mixing the main agent and the curing agent, it is possible for both the first resin composition and the second resin composition to keep the difference in physical properties between the inner layer side and the outer layer side small, and the strength can be increased.

Claims

A manufacturing method for a fiber-reinforced resin molded product, comprising impregnating a fiber layer (12) with resin, the manufacturing method comprising: installing (S11) a parison (10) comprising at least a liner (11) and a fiber layer (12) in the mold (20) and evacuating the mold (20); supplying (S12) a predetermined supply amount of a first resin composition to the fiber layer (12) and stopping the supply of the first resin composition when the predetermined supply amount is reached; changing (S13) to a relief state after the supply of the first resin composition is stopped, to move an upper mold (21) and a lower mold (22) to be slightly separated from each other, thereby relaxing a force for pressing the parison (10); starting (S14) supplying a second resin composition to the fiber layer (12); changing (S15) to a fastened state during supplying the second resin composition to move the upper mold (21) and the mold (22) to be close to each other, thereby increasing a pressure on the second resin composition; stopping (S16) supplying the second resin composition and allowing the second resin composition to cure; and releasing (S17) the resin-impregnated preform (10) from the mold (20); wherein a curing start temperature of the first resin composition is higher than a curing start temperature of the second resin composition, and wherein the first resin composition is supplied so as to reach an outer peripheral portion of the fiber layer (12) of the parison (10) installed in the mold (20), and further impregnated until it reaches an innermost layer side of the fiber layer (12).The manufacturing method according to claim 1, wherein: the mold (20) is used to impregnate the fiber layer (12) with the resin; and a temperature of the mold (20) is set lower than the curing start temperature of the first resin composition and higher than the curing start temperature of the second resin composition.The production method according to claim 1 or 2, wherein a supply amount of the first resin composition is 50% by mass or more and 67% by mass or less with respect to a total supply amount of the first resin composition and the second resin composition.The production method according to any one of claims 1 to 3, wherein in each of the first resin composition and the second resin composition, curing is started by mixing a main agent and a curing agent, and the main agent of the first resin composition and the second resin composition is the same material.The production method according to claim 4, wherein the curing agent in the first resin composition comprises aromatic polyamines and the curing agent in the second resin composition comprises aliphatic polyamines.The manufacturing method according to claim 4 or 5, wherein the temperature of the mold (20) is adjusted and the curing agent is used so that the flowability is not lost until the first resin composition reaches the innermost layer side of the fiber layer (12).

Images