JP4826176B2 - Reinforcing fiber preform and RTM molding method - Google Patents

Description

  The present invention relates to a reinforced fiber preform for a reinforced fiber plastics (hereinafter referred to as FRP) molded body in which reinforced fibers are disposed in a hollow core, and an RTM molding method of a hollow structure FRP using the reinforced fiber preform. .

  Since fiber reinforced plastics (abbreviated as FRP) satisfy the required properties such as excellent mechanical properties and weight reduction, they are used in various applications as structures that replace metal materials.

  Examples of FRP molding methods include resin transfer molding method (hereinafter referred to as RTM molding method), hand lay-up molding method, autoclave molding method, etc. Among them, the RTM molding method is formed of upper and lower molds. Place the reinforcing fiber base in the cavity in the mold, close the mold (in some cases, after reducing the pressure of the cavity), pressurize the liquid resin into the cavity and impregnate the reinforcing fiber base and heat Since it is a molding method to be cured, it can be said to be a molding method with high productivity because it has high molding accuracy and enables relatively stable production.

  In order to further reduce the weight, for example, a hollow structure that can be thinned by increasing the section modulus of the molded product structure even under the same rigidity condition, such as a liquid storage tank or a hollow wind turbine blade. Can be considered. As a method for forming the hollow structure, for example, an inner layer body (core) having a hollow cross section made of a thermoplastic resin is disposed, and resin impregnation molding is performed with reinforcing fibers placed around the inner layer body. A method (for example, refer to Patent Document 1), an elastic bag is placed between reinforcing fibers and set in a mold, and a fluid higher than a resin injection pressure is press-fitted into the elastic bag to place the reinforcing fibers on the molding surface. A method of resin impregnation molding in a pressed state (for example, see Patent Document 2) is known.

  Further, in FRP, in particular, carbon fiber reinforced plastic (abbreviated as CFRP), surface design may be required as a product target. For example, a method for obtaining a FRP having a well-woven structure by suppressing the fiber disturbance by pressing the preform of the reinforcing fiber fabric, preventing the deformation of the preform of the reinforcing fiber fabric at the time of resin injection (for example, patent document) 3), or when the reinforcing fiber dry cloth (woven fabric not filled with resin) forming the surface portion of the FRP structure is placed in a mold having a curved surface portion, the direction along the yarn on the dry cloth. A mark corresponding to the reference line is attached to the mold, and the dry cloth is shaped along the curved surface of the mold while aligning the reference line of the dry cloth with the mark. A reinforced fiber preform and an RTM molding method using the reinforced fiber preform (for example, see Patent Document 4) are known.

However, with these methods, it has been difficult to stably obtain a hollow structure having a high surface quality that is free from fiber turbulence and deformation such as bending and gaps in the reinforcing fibers of the surface layer (design layer).
Japanese Patent Laid-Open No. 64-34725 JP-A-4-246510 JP 2004249595 A JP 2003-127157 A

  An object of the present invention is to provide a reinforcing fiber preform capable of obtaining a hollow structure FRP having a high surface quality free from fiber disturbance such as bending and deformation in the reinforcing fiber of the design layer, and an RTM molding method using the same. It is.

  The inventors of the present invention have investigated the cause of failure to obtain a hollow structure FRP having a high surface quality in the RTM molding method of a hollow structure according to the conventional method. As a result, the flow pressure of a pressurized injected resin acting during RTM molding is investigated. Under the idea that surface reinforcing fibers may be disturbed or deformed by the reinforced fiber preform form in which tension is applied to the reinforcing fibers at the time of RTM molding, the surface quality is compared with the conventional method. Has found that it can provide a much better method.

That is, the reinforcing fiber preform according to the present invention is a reinforcing fiber preform including a main body layer of reinforcing fibers disposed in a hollow core and a design layer covering the surface of the main body layer, and the number of the design layers is two or more. consists of two or more regions corresponding to each type of the mold consisting of the mold, Rutotomoni provided a mold parting portion corresponding to them boundaries between each area, the seam of the design layer between said region This is a reinforcing fiber preform that is projected so as to be sandwiched between parting portions of a mold . As possible out exerting tension to該意Takumi layer by sandwiching Mukoto a reinforcing fiber base material of the design layer in the form of parting zone by applying or mow reinforcing fibers preform.

Furthermore, it is preferable before Kinakazora core is reinforced fiber preform is blow molded article.

  Moreover, the RTM molding method of the hollow structure FRP according to the present invention includes two or more molds corresponding to each mold of a body layer disposed on the hollow core and two or more molds covering the surface of the body layer. Place the reinforcing fiber preform including the design layer consisting of regions so that the boundary between the regions of the design layer corresponding to the mold is clamped by the parting part of the mold, and press the hollow core with compressed air It is characterized in that it is molded by impregnating and curing a resin under pressure at the same or low pressure as that of compressed air while expanding. Preferably, it is an RTM molding method in which the compressed air is sealed in the hollow core after the boundary between the regions of the design layer is clamped with a mold.

  Further, after molding, the hollow core is depressurized once to open the upper mold, and in that state, the low-pressure compressed air is sealed in the core to demold the hollow structure FRP molded body. preferable.

  According to the RTM molding method of the hollow fiber FRP using the reinforcing fiber preform and the reinforcing fiber preform according to the present invention, RTM molding can be performed while applying tension to the reinforcing fiber of the design layer. The hollow structure FRP which prevents and has a high surface design property is obtained.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

  FRP in the present invention refers to a resin reinforced with reinforcing fibers, and examples of reinforcing fibers include inorganic fibers such as carbon fibers, glass fibers, and metal fibers, or organic fibers such as aramid fibers, polyethylene fibers, and polyamide fibers. Fiber. Examples of the FRP matrix resin include thermosetting resins such as epoxy resins, unsaturated polyester resins, vinyl ester resins, and phenol resins. Furthermore, polyamide resins, polyolefin resins, dicyclopentadiene resins, polyurethane resins, polypropylene, and the like. A thermoplastic resin such as a resin can also be used.

  In particular, as the resin used in the RTM molding method according to the present invention, a thermosetting resin having a low viscosity and easily impregnating reinforcing fibers, or a monomer for RIM (Reaction Injection Molding) that forms a thermoplastic resin is suitable. is there. Among them, from the viewpoint that the thermal shrinkage of the FRP structure can be reduced and the occurrence of cracks can be suppressed, as the thermosetting resin, modified epoxy resins and vinyl ester resins containing an epoxy resin, a rubber component, etc. As the thermoplastic resin, nylon resin, dicyclopentadiene resin and the like are preferable.

  The hollow core used in the hollow structure FRP molding according to the present invention includes a hollow structure formed by blow molding or rotational molding, a hollow structure formed by fusing a film into a bag shape, and shaped like a balloon by dipping. And a rubber hollow structure having Among them, a blow molded body that can cope with a complicated curved surface shape or a shape with severe irregularities and is easy to recycle in terms of environmental aspects is preferable. Examples of the material include thermoplastic resins such as polypropylene, polyethylene, ABS, and nylon, natural rubber, silicon rubber, and neoprene rubber.

The mold used in the present invention must be composed of two or more molds. For example, an upper mold and a lower mold can be used. When such a mold is used, the reinforcing fiber base material is disposed on the lower mold while the upper mold is disposed upward by the mold lifting device. This reinforcing fiber base is prepared in advance as a reinforcing fiber preform formed into a product shape so as to be easily accommodated in the lower mold by a shaping mold. Examples of the material of the mold include FRP, cast steel, structural carbon steel, aluminum alloy, zinc alloy, nickel electroforming, and copper electroforming. For mass production, structural carbon steel is suitable in terms of rigidity, heat resistance and durability.

FIG. 1 shows a molding system for carrying out a method for producing an FRP molded body according to an embodiment of the present invention. In FIG. 1, reference numeral 2 denotes a molding die including an upper die and a lower die, and the upper die is attached to the die lifting device 1. The mold lifting / lowering apparatus 1 has a hydraulic unit 9 including a hydraulic pump 10 and a hydraulic cylinder 11, and the operation and pressurization of the upper mold are controlled by hydraulic pressure.

  As shown in FIG. 2, for example, when the molding die 2 is a molded body having an undercut portion, the split mold 18 may be disposed on a part of the lower mold. RTM molding can be performed in a state where the design layer base material is sandwiched between the parting portions of the mold generated in the split mold, and the base material can be prevented from being disturbed to obtain high quality in the entire design layer.

  The molding die 2 is connected with a resin injection channel 13 connected to the injection port 8a and a discharge channel 14 connected to the discharge port 8b. The resin injection channel 13 and the discharge channel 14 are connected to the injection port 8a and the discharge port 8b via an injection valve 22a and a discharge valve 22b, respectively. The opening / closing operation of the injection valve 22a and the discharge valve 22b and the operation timing thereof are performed based on commands from the control device 22c.

  The injection valve 22a and the discharge valve 22b installed in the middle of the resin injection flow path 13 and the discharge path 14 at the time of resin injection can be opened / closed and the diameter of the entire area can be changed by directly sandwiching the flow path by an operator with a vise grip or the like. Can do. For example, as shown in FIG. 2, a vise grip 21 may be provided in the middle of the resin injection flow path 13 and the discharge path 14 connected to the upper mold 16 side of the molding die including the upper mold 16 and the lower mold 17. it can.

  A resin injection device 3 is connected to the resin injection flow path 13. The resin injection device 3 stores the main agent and the curing agent in the main agent tank 5 and the curing agent tank 6, respectively, and each tank has a mechanism capable of heating and can be degassed by the vacuum pump 24. Yes. At the time of resin injection, the resin is pushed from each tank toward the resin injection flow path 13 by the pressurizing device 23. A syringe pump is used for the pressurizing device 23 provided via the check valve 12, and it is preferable for a resin that is cured by two-liquid mixing to ensure quantitativeness by simultaneously extruding the syringe. The main agent and the curing agent are mixed by the mixing unit 4 and reach the resin injection channel 13. A resin trap 15 is interposed in the discharge path 14 in order to prevent the resin from flowing into the vacuum pump 7a or the pressure pump 7b.

  The material of the resin injection flow path 13 needs to ensure sufficient flow rate and compatibility with the resin (temperature, solvent resistance, pressure resistance). A tube with a diameter of 5 to 30 mm is used. A pressure resistance of 1.0 MPa or more is required to withstand the injection pressure of the resin, and a heat resistance of 100 ° C. or more is required to withstand the temperature during resin curing, and the thickness is 2 mm. A tube made of fluororesin such as “Teflon (registered trademark)” is suitable. However, other than “Teflon (registered trademark)”, a relatively inexpensive plastic tube such as polyethylene or nylon, or a metal tube such as steel or aluminum may be used.

  As for the material of the discharge passage 14, it is necessary to take into consideration the securing of a sufficient flow rate and compatibility with the resin (temperature, solvent resistance, pressure resistance) in the same manner as the resin injection passage 13. The discharge path 14 may be a metal tube such as steel or aluminum, or a plastic tube such as polyethylene, nylon, or “Teflon (registered trademark)”, but “Teflon (registered) having a diameter of 5 to 10 mm and a thickness of 1 to 2 mm. (Trademark) "tube is more preferable from the viewpoint of workability.

  The pressurization of the resin can also provide quantitativeness according to the pressurization method using a syringe pump or the like as described above. The resin injection pressure Pi is preferably in the range of 0.1 to 1.0 MPa. Here, the injection pressure Pi of the resin refers to the maximum pressure pressurized by the pressurizing device 23, and represents the pressure displayed by the pressure gauge 31 of the injected resin in FIG. When the resin in the mold is finally completely impregnated with the resin and reaches the discharge path 14, the discharge path 14 is closed, and after a while, the resin injection path 13 is also closed and the resin injection is finished. The molding die 2 is heated by, for example, temperature controllers 25 and 26, thereby curing the resin. The in-mold resin pressure Pm represents the pressure of the in-mold resin pressure gauge 32. Therefore, the relationship with the injection pressure Pi is Pm ≦ Pi, and Pm <Pi when the resin is flowing in the molding die. Only when the resin is completely filled in the mold, the discharge valve 22b is closed and the resin flow is stopped, and when the resin pressure is applied from the resin injection pump, Pm = Pi.

As one embodiment of the present invention, a molding method relating to a hollow wing structure will be described below.
First, FIG. 4 and FIG. 5 show a molding die 2 used for RTM molding of the hollow wing structure. The molding die 2 composed of an upper die 54 and a lower die 55 is provided with an injection port 58a for injecting resin and a suction / discharge port 58b for vacuum suction of the inside of the die, and a compressed air that applies pressure such as gas to the inside of the hollow structure. In this structure, a mouth 52 is provided. A is the injected resin, B is the suction of air and excess resin from the mold, and C is the compressed air supplied to the hollow core (pressure air).

  When the hollow wing structure is formed, the following steps are sequentially performed.

  (1) A reinforcing fiber preform 33 in which a reinforcing fiber base 35 is arranged on a hollow core 34 that can be expanded and contracted as shown in FIG. 3 is formed in advance. At this time, the reinforcing fiber base may be slightly shorter than the hollow core so that the reinforcing fiber base is completely impregnated with the resin.

  (2) Next, as shown in FIG. 4, the reinforcing fiber preform is placed in the lower mold cavity (substantially the same shape as the reinforcing fiber preform).

  (3) The upper die 54 is lowered by a press machine or the like (not shown) and pressed against the lower die as shown in FIG. 5 to seal the inside of the molding die. In this state, the resin injection tube is connected to the injection port 58a, and the suction / discharge tube is connected to the suction / discharge port 58b. Further, the compressed air sealing tube is connected to a compressed air port 52 provided in the hollow core 34.

  (4) After that, pressurized air that forms a predetermined pressure is sealed in the hollow core 34 from the pressure port 52, and the hollow core 34 is expanded.

  (5) The expanded hollow core 34 presses the reinforcing fiber base 35 disposed on the outer periphery of the hollow core against the cavity surface of the molding die.

  (6) Next, vacuum suction is performed from the suction / discharge port 58b with the injection port 58a closed, and the inside of the molding die is continuously decompressed.

  (7) In that state, the injection port 58a is opened, and a pressurized resin is injected from the resin injection device 3 shown in FIG.

  (8) The resin injected from the injection port 58a is once stored in the resin injection runner 56 and then flows toward the suction runner. In the meantime, the injection resin impregnates the reinforcing fiber base 35.

  (9) After that, when the injected pressurized resin starts to flow out from the suction / discharge port 58b, the suction / discharge port 58b is closed by the vice grip 21 shown in FIG.

  (10) While operating the resin injection device, the suction / discharge port 58b is kept closed for a predetermined time while applying the resin pressure (static pressure) from the injection port 58a.

  (11) The mold is initially heated to a predetermined temperature from [Step (2)], and the resin is cured in the step (10).

  (12) Next, the upper die 54 is slightly raised from the lower die 55, and then pressurized air pressure is applied to the inside of the hollow core 34 from the pressurized air port 52 (low pressure of 0.1 Mpa or less is sufficient) The hollow structure FRP molded body 53 is released from the lower mold 55 by expanding and deforming the child. Thereby, it is possible to prevent the FRP molded body from being damaged by a demolding tool or the like, and to shorten the time required for demolding.

  (13) Then, after raising the upper mold 54 completely, the hollow structure FRP molded body 53 is removed from the lower mold 55.

  However, when trying to mold a hollow FRP structure using a reinforcing fiber preform in which the reinforcing fiber base is only disposed in the hollow core, the outermost reinforcing fiber base serving as the design layer is a mold molding cavity. When pressed against a surface, only the pressing force acts on the outermost reinforcing fiber substrate, and there is a problem that fiber disturbance occurs because no tension acts at all.

  Therefore, in the present invention, as shown in FIG. 6, the reinforcing fiber base disposed in the hollow core 34 includes a main body layer base 38 that exhibits mechanical properties (strength and rigidity), and a design that exhibits appearance design. The reinforcing fiber preform 36 in which the design layer base material 37 is arranged so as to cover the main body layer base material 38 is formed separately from the layer base material 37. And the boundary part between each area | region of the design layer base material 37 corresponding to each type | mold (in this case, upper mold | type and lower mold | type) which comprises this shaping | molding die for this reinforcing fiber preform 36 is a parting part of a shaping | molding die. By placing them so as to be pinched, a tensile force is surely applied to the design layer substrate 37. That is, as shown in FIG. 6, between the two areas of the upper mold area and the lower mold area where the design layer base material 37 is disposed, it is located in the parting line of the mold that becomes the boundary between them. As shown in FIG. 7, by extending the F portion and the R portion, which are joints of the design layer base material 37, for example, several mm, the joint of the design layer base material 37 between the lower die 55 and the upper die 54 is lowered as shown in FIG. 7. In this state, a tension T is generated in the entire design layer base material 37 by sandwiching the F portion and the R portion, and enclosing the compressed air in the hollow core 34 and expanding it. Due to the generation of the tension T, the surface design of the hollow wing structure can be improved stably and drastically without causing any fiber disturbance of the design layer base material 37 even when the injection resin pressure acts. It was.

  In the present invention, if the length of the design layer base material clamped by the parting part of the molding die exceeds the runner part, the resin injection from the runner becomes defective or the mold clamping becomes worse. The seal part (not shown) located on the outer periphery of the runner becomes dysfunctional, resulting in an increase in resin leakage and unnecessary burrs. Therefore, it is preferably about 1 mm or more from the end of the cavity and inside the runner site.

  In addition, an appropriate gap (a level at which the base material does not move due to the resin pressure) is provided between the cavity and each runner for injection and suction depending on the number of design reinforcing fiber bases to be sandwiched. There is a need.

  Below, based on the Example of this invention, it demonstrates more concretely. In the examples, the following reinforcing fiber substrate, resin, and hollow core that can be expanded and contracted were used.

(1) Substrate a: Carbon fiber woven fabric CO6644 manufactured by Toray Industries, Inc. (woven structure: T300 plain weave, woven fabric weight: about 300 g / m ² , machine width 1000 mm)
(2) Base material b: Carbon fiber woven fabric CO6343 manufactured by Toray Industries, Inc. (woven structure: T300 plain weave, woven fabric weight: about 200 g / m ² , machine width 1000 mm)
(3) Resin a: “Epicoat (registered trademark)” 828 / TR-C35H = 100/10, however, “Epicoat (registered trademark)” 828: Epoxy resin manufactured by Japan Epoxy Resin Co., Ltd., TR-C35H: Toray ( Co., Ltd., imidazole derivatives (4) Hollow core: polyethylene blow molded article (average thickness: about 2 mm) having a cross-section of a hollow blade having a length of 1200 mm and a width of 250 mm
<Example 1>
As shown in FIG. 3, the reinforcing fiber base material 35 is wound around the hollow core 34 from the inside, and the base material a is wound three times as the main body layer base material 38 shown in FIG. As 37, a reinforcing fiber preform 36 in which one ply of the base material b was disposed was produced. However, the base material b used as the design layer base material 37 was arranged in a C shape with an end provided on one side as shown in FIG.

  Further, in the molding process, as shown in FIG. 7, the F portion and the R portion that are pressed portions protrude about 8 mm so that the base material b of the design layer base material 37 is securely sandwiched by the parting portion of the mold. A reinforced fiber preform 36 was obtained.

<Example 2>
The reinforcing fiber preform 36 was set in the molding die 2 (consisting of an upper die 54 and a lower die 55) shown in FIG. Specifically, after the reinforcing fiber preform 36 is set on the lower mold 55 of FIG. 4 and the upper mold 54 is lowered and clamped, the resin injection port 58a, the suction / discharge port 58b and the compressed air port 52 shown in FIG. Tubes were connected (not shown).

  Next, compressed air pressurized to 0.6 MPa was sealed in the hollow core 34 and held. The mold 2 was connected to the temperature controller 26, which is a hot water heater, for both the upper and lower molds (54, 55), and was set so that the mold temperature was maintained at 95 ° C. The molding die 2 communicated with the vacuum pump 7a through the resin trap 15. After the mold was clamped, the inside of the mold was vacuumed by opening the discharge valve 22b.

  Next, after closing the discharge valve 22b, the main agent and the curing agent are individually vacuum degassed and the mixed resin a is opened from the resin injection device 3 by opening the injection valve 22a communicating with the injection port 58a. The resin pressure Pi was injected at 0.5 MPa. In about 3 minutes after the start of injection, a small amount of the resin a flowed out to the discharge valve 22b side. Then, the discharge valve 22b was closed for 20 seconds, and then the discharge valve 22b was opened for 20 seconds. Then, the closing and opening of the discharge valve 22b was repeated three times. Finally, the discharge valve 22b was closed, and after 2 minutes, the injection valve 22a was also closed. Thereafter, the state as it was was kept for 20 minutes to cure the resin a.

  After curing, the pressure of the hollow core 34 in the hollow structure FRP molded body was released to the atmosphere. Then, the upper mold 54 of the molding die 2 was raised and stopped in a state where it was floated by about 15 mm. Next, when compressed air having a pressure = 0.02 MPa was sealed in the hollow core 34, the hollow structure FRP compact was released from the molding die 2.

  Thereafter, the upper die 54 was completely raised, and the hollow structure FRP molded body together with the hollow core 34 was taken out from the molding die 2.

  Then, the hollow core 34 was contracted and deformed by vacuum suction and held under reduced pressure, and the hollow core 34 could be extracted from the hollow structure FRP molded body.

  When the surface of the molded product was confirmed, there was no fiber disturbance in the design layer, and the surface quality was very high.

<Example 3>
As shown in FIG. 8, as the reinforcing fiber preform 39, the base material a is wound around the hollow core 34 as a main body layer five times, and the design layer base material 40a divided into two parts vertically on the main body layer, It was set as the structure which arrange | positioned the base material a as the design layer base material 40b. The design layer base material 40a and the base material a for the design layer base material 40b were protruded by about 10 mm from the F part and the R part so that both can be sandwiched between the parting parts of the mold.

  Except for the application of the reinforcing fiber preform 36, RTM molding was performed in the same manner as in Example 1 to obtain a hollow structure FRP molded body. When the surface of the molded product was confirmed, the design layer had no fiber disturbance as in Example 1, and the quality was extremely high.

<Comparative Example 1>
As shown in FIG. 9, as the reinforcing fiber preform 42, the base material b is wound around the hollow core 34 as a main body layer three times from the inside, and the base material a is formed as a design layer base material 43 on the C shape. It was set as the structure arrange | positioned. However, as for the base material a of the design layer base material 43, the protruding portion sandwiched between the parting portions of the mold was only the base material end portion (F portion) on one side.

  As in Example 2, except for the reinforcing fiber preform 36, RTM molding was performed in the same manner as in Example 1 to obtain a hollow structure FRP molded body. Since one side of the design layer base material of the molded body is not clamped by the parting portion of the mold, the tension generated on the base material a of the design layer base material 43 is insufficient, so the surface of the molded body is confirmed. As a result, fiber disturbance of the design layer was partially generated.

<Comparative example 2>
Similarly, the reinforcing fiber preform 45 is arranged in the order of the main body layer base material 47, the design layer base material 46a, and the design layer base material 46b from the inside around the hollow core 34 as shown in FIG. . And the base material a of the design layer base material 46a and the design layer base material 46b was not provided with a protruding portion so that it could not be sandwiched at all by the parting part of the mold.

  Except for using the reinforcing fiber preform 36, RTM molding was performed in the same manner as in Example 1 to obtain a molded body similar to the above. In the molded body, the design layer base materials 46a and 46b are not clamped at all by the parting portion of the mold, so that the base material a of the design layer is completely pressed only by pressing on the mold surface due to the expansion of the hollow core 34. Since no tension was generated, when the surface was checked, fiber disturbance of the design layer was seen throughout.

  The present invention is suitable for all FRP molded products having a hollow structure, particularly for the production of FRP having a hollow structure that requires high surface quality with no fiber disturbance on the design surface. Applications include liquid storage tanks, wind turbine blades, automotive components (spoilers, bumpers, reinforcement members, etc.), aircraft components (secondary structure materials, interior materials, reinforcement members), hollow construction panel materials, and other general industrial applications. It can be applied to a hollow member.

It is a systematic diagram of the RTM shaping | molding system which concerns on one embodiment of this invention. It is a schematic perspective view of the molding die concerning one embodiment of the present invention. It is a perspective view of the reinforced fiber preform which shows an example of this invention. FIG. 4 is an arrangement view of the reinforcing fiber preform shown in FIG. 3 on a molding die. FIG. 5 is a diagram showing a state of clamping after the reinforcing fiber preform is arranged in FIG. 4. It is sectional drawing of the reinforced fiber preform which shows an example of this invention. It is sectional drawing of the state arrange | positioned to the metal mold | die of the reinforced fiber preform shown in FIG. It is sectional drawing of the reinforced fiber preform which shows an example of this invention. It is sectional drawing of the reinforced fiber preform which shows the comparative example with this invention. It is sectional drawing of the reinforced fiber preform which shows the comparative example with this invention different from FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mold raising / lowering device 2 Molding die 3 Resin injection device 4 Mixing unit 5 Main agent tank 6 Hardener tank 7a Vacuum pump 7b Pressure pump 8a Inlet 8b Outlet 9 Hydraulic unit 10 Hydraulic pump 11 Hydraulic cylinder 12 Check valve 13 Resin injection flow path 14 Discharge path 15 Resin trap 16 Upper mold 17 Lower mold 18 Split mold 21 Vise grip 22a Injection valve 22b Discharge valve 22c Control device 23 Pressurization device 24 Vacuum pump 25, 26 Temperature controller 31 Pressure gauge for injection resin 32 Pressure gauge of resin in mold 33, 36, 39, 42, 45 Reinforcing fiber preform 34 Hollow core 35 Reinforcing fiber substrate 37, 40a, 40b, 43, 46a, 46b Design layer substrate 38, 41, 44, 47 Body layer base material 52 Air pressure port 54 Upper die 55 Lower die 56 Resin injection runner 57 Suction discharge Runner 58a inlet 58b suction outlet port

Claims (5)

A reinforcing fiber preform including a main body layer of reinforcing fibers disposed in a hollow core and a design layer covering the surface of the main body layer, wherein the design layer corresponds to each mold of a two or more molds consists of two or more regions and is projected to be able to sandwich the boundary portion between the region Rutotomoni provided the parting portion of the corresponding type, the seam of the design layer between said region at the mold parting portion Reinforced fiber preform characterized by that. The reinforcing fiber preform according to claim 1, wherein the hollow core is a blow molded article.   A reinforcing fiber preform including a reinforcing fiber main body layer disposed in a hollow core and a design layer including two or more regions corresponding to each mold of the two or more molds covering the surface of the main body layer. The resin layer is placed on the mold so that the boundary between the regions of the design layer is clamped by the parting part of the mold, and the resin is applied at the same or low pressure as the compressed air while the hollow core is expanded with compressed air. A method for RTM molding of a hollow structure FRP, wherein the molding is performed by pressure injection, impregnation and curing. 4. The method for forming an RTM of a hollow structure FRP according to claim 3 , wherein the air pressure is sealed in the hollow core after the boundary between the regions of the design layer is clamped with a mold. After molding, once reduced pressure a hollow core, hollow structure according to any one of the low pressure compressed air in the open state of the upper die according to claim 3 or 4, characterized in that demolding enclosed in the core FRP RTM molding method.

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