JP2007090810A - Method for manufacturing hollow frp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for stably manufacturing an FRP member without impairing the appearance such as a sink mark and being rich in a resin caused by dimensional variation of a core due to pressure of the injected resin, an increase in weight caused by penetration of the matrix resin into the core, and decrease in strength caused by interfacial releasing, when the FRP member with a wing shape of a hollow structure is prepared using a preform in which a reinforcing fiber base material is wound on the core in the wing chord length direction of the core by RTM (Resin Transfer Molding). <P>SOLUTION: When the preform in which the reinforcing fiber base material is wound on the core with the wing-shaped hollow structure having a straight line part on at least one part of the cross-section in the wing chord length direction of the core, is prepared, the preform in which the wound tensile force is controlled so as to satisfy both an equation (1): 100*äX-(Y+Z)}=A (A≤0) and an equation (2): 0.3≤¾A¾<0.7 (wherein X: the dimension of the wing chord length after the reinforcing fiber is wound, Y: the thickness of the wound reinforcing fiber base material, and Z: the dimension of the wing chord length of the core single body), is prepared, and while an inner pressure is given to the preform, the RTM molding is performed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing a reinforcing fiber plastic member having a hollow wing shape in a RTM (Resin Transfer Molding) molding method.

  In recent years, a member made of reinforced fiber plastic (hereinafter referred to as FRP) using glass fiber or carbon fiber as a reinforced fiber base material has attracted attention because it is relatively lightweight and has a high rigidity starting from automobile use. It has become like this.

  As an FRP production method, an autoclave molding method, a press molding method, an RTM (Resin Transfer Molding) molding method (hereinafter referred to as an RTM molding method) and the like are widely known. Among them, the RTM molding method is excellent in molding accuracy and mass productivity. It can be said that it is a molding method.

For example, when molding wing-shaped members that require lightweight, high rigidity, and high quality, such as automobile rear spoilers and blowers, the core of a lightweight elastic material such as polyurethane foam is reinforced. A preform wrapped with fibers or a preform wrapped with a reinforcing fiber divided vertically is set in a mold, a thermosetting resin is injected into the mold, and the resin is cured at the temperature of the mold It is known that it can be manufactured by making it. (See Patent Document 1 and Patent Document 2). However, in the composite structure of reinforcing fibers and cores, the rigidity of the molded body is improved, but the surface dents called sinks caused by the dimensional variation of the core due to the injection resin pressure, the inside of the matrix resin core Many potential problems remain, such as an increase in weight due to permeation of water and a decrease in strength due to peeling at the interface. Therefore, there is a need for a technology that can produce FRP members with a hollow wing shape that do not have a core in the FRP and do not remain in the FRP without damaging elements such as lightness, high rigidity, and high quality by the RTM molding method. It becomes.
Japanese Patent Laid-Open No. 2-92524 JP-A-7-1607

  The problem to be solved is when an FRP member having a hollow wing shape is formed by RTM molding using a preform in which a reinforcing fiber base is wound around the core in the chord length direction of the core. , A method that enables stable production without appearance defects such as sink marks and resin richness caused by core size variation due to injected resin pressure, weight increase due to penetration into the core of the matrix resin, and strength reduction due to peeling from the interface Is to provide.

In order to solve the above problems, the following configuration is adopted.
(1) When preparing a preform in which a reinforcing fiber base is wound in the direction of the chord length of the core on a core of a wing-shaped hollow structure having a straight portion in at least a part of the cross section, the following formula A method for producing FRP, characterized in that a winding tension is controlled so as to satisfy the above conditions, and RTM molding is performed while applying an internal pressure to the preform.

100 * {X− (Y + Z)} / Z = A (A ≦ 0) (1)
0.3 ≦ | A | <0.7 (2)
In the formula, X: chord length after winding the reinforcing fiber Y: thickness of the wound reinforcing fiber substrate Z: chord length of the core alone (2) Tensile modulus of the reinforcing fiber substrate is 50 GPa or more The manufacturing method of FRP as described in said (1) using the reinforcing fiber of.
(3) FRP manufacturing method in any one of said (1) or (2) whose bending elastic modulus of core material is the range of 300-10,000 MPa (4) Plate thickness is 0.6-4.0 mm The manufacturing method of FRP in any one of said (1)-(3) which is a core.
(5) The FRP manufacturing method according to any one of (1) to (4) above, wherein the core is removed from the FRP body after RTM molding. (6) The core material has releasability from the matrix resin. The FRP manufacturing method according to any one of (1) to (5), wherein the core has at least one opening, and is any one of the above (1) to (6) The FRP manufacturing method as described.
(8) The FRP production method according to any one of (1) to (7), wherein a core of a thermoplastic resin material is used.
(9) The FRP manufacturing method according to any one of (1) to (8), wherein a blow-molded core is used.

  According to the present invention, it is possible to manufacture an FRP member having a hollow wing shape that is lighter than the conventional RTM molding method, stably develops strength, and obtains high quality.

The best mode of the present invention will be described below with reference to the drawings.

  FRP in the present invention refers to a resin reinforced with reinforcing fibers, and examples of reinforcing fiber base materials include inorganic fibers such as carbon fibers, glass fibers, and metal fibers, or aramid fibers, polyethylene fibers, polyamide fibers, and the like. Organic 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 A thermoplastic resin such as a resin can also be used.

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

  Examples of the material of the hollow core having a wing shape having a hollow structure according to the present invention include thermoplastic resins such as polypropylene, polyethylene, ABS, and nylon, natural rubber, silicon rubber, neoprene rubber, and the like. Polypropylene having the following releasability (no polarity) is preferred. The core molding method includes a hollow structure formed by blow molding or rotational molding, a hollow structure formed by fusing a film into a bag, and a rubber hollow structure having a balloon-like shape by dipping Etc. Among them, a hollow structure formed by blow molding 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.

As the mold used in the present invention, for example, a mold composed of an upper mold and a lower mold is 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 produced in advance by a shaping mold as a preform shaped into a product shape so as to be easily accommodated in the lower 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 of manufacturing an FRP member having a hollow wing shape 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 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 forming method relating to a structure having a hollow wing shape will be described below.

First, FIGS. 6 and 7 show a molding die 2 used for RTM molding of an FRP member having a hollow wing shape. The molding die 2 including the upper mold 42 and the lower mold 43 is provided with an injection port 46a for injecting resin and a suction / discharge port 46b for vacuum suction of the inside of the mold, and applies pressure such as gas to the inside of the hollow structure core. In this structure, the compressed air port 41 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 forming an FRP member having a blade shape of a hollow blade structure, the following steps are sequentially performed.
(1) When creating the preform 33 in which the reinforcing fiber base materials 36 and 40 are wound around the core 34 having a hollow shape as shown in FIG. The preform is created by controlling the winding tension so as to satisfy the following formula.

100 * {X− (Y + Z)} / Z = A (A ≦ 0) (1)
0.3 ≦ | A | <0.7 (2)
In the formula
X: Chord chord length after winding the reinforcing fiber
Y: thickness of the wound reinforcing fiber base
Z: chord length dimension of core alone (2) Next, as shown in FIG. 6, the preform 33 is placed in a lower cavity (substantially the same shape as the preform).
(3) The upper die 42 is lowered by a press machine or the like and pressed against the lower die as shown in FIG. 7 to seal the inside of the molding die. In this state, the resin injection tube is connected to the injection port 46a, and the suction / discharge tube is connected to the suction / discharge port 46b. Further, the compressed air sealing tube is connected to a compressed air port 41 provided in the hollow core 34.
(4) After that, pressurized air that forms a predetermined pressure from the compressed air port 41 is sealed in the hollow core 34, and the hollow core 34 is expanded.
(5) The expanded hollow core 34 causes the reinforcing fiber bases 36 and 40 disposed on the outer periphery of the hollow core to press against the cavity surface of the molding die.
(6) Next, vacuum suction is performed from the suction / discharge port 46b in a state where the injection port 46a is closed, and the inside of the molding die is continuously decompressed.
(7) In that state, the injection port 46a is opened, and the pressurized resin is injected from the resin injection device 3 shown in FIG.
(8) The resin injected from the injection port 46 a is once stored in the resin injection runner 44 and then flows toward the suction runner 45. In the meantime, the injected resin impregnates the reinforcing fiber bases 36 and 39.
(9) Thereafter, when the injected pressurized resin starts to flow out from the suction / discharge port 46b, the suction / discharge port 46b is closed by the vice grip 21 shown in FIG.
(10) While operating the resin injection device, the suction / discharge port 46b is kept closed for a predetermined time while applying the resin pressure (static pressure) from the injection port 46a.
(11) The mold is initially heated to a predetermined temperature from [Step (2)], and the resin is cured in the step (10).

(12) Next, after slightly raising the upper die 42 from the lower die 43, a vacuum pressure is applied to the core 34 from the pressure port 41 (may be several seconds), and the core is shrunk and deformed. The wing-shaped FRP molded body having a structure is released from the lower mold 43.
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 the upper mold 42 is completely raised, the FRP molded product having a hollow wing shape is removed from the lower mold 43.

Below, based on the Example of this invention, it demonstrates more concretely. In the examples, the following reinforcing fiber base, resin, and core were used.
(1) Substrate Toray Co., Ltd. carbon fiber woven fabric CO6343 (woven structure: T300 plain weave, fabric weight: about 300 g / m ² , machine width 1000 mm)
(2) Resin “Epicoat (registered trademark)” 828 / TR-C35H = 100/10
However, “Epicoat (registered trademark)” 828: Epoxy resin manufactured by Japan Epoxy Resin Co., Ltd.,
TR-C35H: manufactured by Toray Industries, Inc., imidazole derivative (3) core: polypropylene blow-molded body (average thickness: about 1.7 mm) having a length of 1200 mm and a width of 250 mm.
<Example 1>
3 to 5 show a preform manufacturing method. As shown in FIG. 3, using a base material winding system 47 originally devised to efficiently produce a reinforcing fiber preform, around the core 34 whose chord length length has been measured in advance, The base material 36 unwound from the original fabric 35 is pasted and wound twice while rotating the core. Thereafter, a heat-fusible tape 37 is attached with an iron 38, and after the heat is removed from the tape, the base material is wound once more (three times in total). As shown in FIG. 4, a 6 kgf weight 39 calculated in advance taking into account the deformation amount of the core is placed between the core and the original fabric, and the tension is applied to the base material. Heat is applied to the portion corresponding to 37 with the iron 38 from above the base material wound around the third time, and the base materials are bonded to each other, and the raw fabric is cut in the immediate vicinity of the bonding portion.

  Then check the chord length and check if it is in the range that satisfies the following formula.

100 * {X− (Y + Z)} / Z = A (A ≦ 0) (1)
0.3 ≦ | A | <0.7 (2)
In the formula, X: chord length dimension after winding the reinforcing fiber Y: thickness of the wound reinforcing fiber base Z: chord length dimension of the core alone After confirming the dimension, the chord length is adjusted to a predetermined dimension as shown in FIG. A base material 40 having the same quality as the cut base material 36 was wound once in a U-shape so that the start and end of winding did not remain in the preform, and a reinforcing fiber preform 33 was produced.

The reinforcing fiber preform 33 was set in the molding die 2 (consisting of an upper die 42 and a lower die 43) shown in FIG. Specifically, after the reinforcing fiber preform 33 is set on the lower mold 43 of FIG. 6 and the upper mold 42 is lowered and clamped, the resin inlet 46a, the suction outlet 46b and the compressed air port 41 shown in FIG. Tubes were connected (not shown).

  Next, pressurized air pressurized to 0.5 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 (42, 43), 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 46a. The resin pressure Pi was injected at 0.5 MPa. In about 1 minute 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 30 seconds, and then the discharge valve 22b was opened for 20 seconds. Then, closing and opening of the discharge valve 22b was repeated three times. Finally, the discharge valve 22b was closed, and after 15 seconds, the injection valve 22a was also closed. Thereafter, the state as it was was maintained for 15 minutes to cure the resin a. During curing, the tubes other than the compressed air port 41 are removed, and the resin inside the tube is washed.

  After curing, the pressure of the hollow core 34 in the hollow structure FRP molded body was released to the atmosphere. And the upper mold | type 42 of the shaping die 2 was raised, and it stopped in the state which floated about 15 mm. Next, when the hollow core 34 was vacuumed and held as it was, the hollow structure FRP molded product was released from the molding die 2.

  Thereafter, the upper die 42 was completely raised, and the hollow structure FRP molded body together with the hollow core 34 was taken out from the molding die 2.

  When the hollow structure FRP molded body was sufficiently removed with the hollow core 34, the hollow core 34 could be pulled out from the opening.

  The molded body was lightweight, had a uniform hollow cross section, and had a very high quality surface.

  INDUSTRIAL APPLICATION This invention can be utilized for the FRP molded object which has the wing | blade shape of a hollow structure, especially the thing where the designability which shows the lightness and the texture of a reinforced fiber fabric is requested | required. Applications can be applied to wind turbine blades, automobile spoilers, and other general industrial hollow members.

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 manufacturing method of the reinforced fiber preform by the substrate winding system which shows an example of the present invention. It is a manufacturing method of the reinforced fiber preform by the substrate winding system which shows an example of the present invention. It is sectional drawing of the reinforced fiber preform which shows an example of this invention. FIG. 6 is a layout view of the reinforcing fiber preform shown in FIG. 5 on a molding die. FIG. 6 is a state diagram of clamping after the reinforcing fiber preform is arranged in FIG. 5.

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 Resin pressure gauge 33 Reinforcing fiber preform 34 Hollow core 35 Raw fabric 36, 40 Reinforcing fiber base material 37 Heat fusion tape 38 Iron 39 Weight 41 Pressure port 42 Upper die 43 Lower die 44 Resin runner 45 Runner for suction discharge 46a inlet 46b suction outlet 47 Base material winding System

Claims (9)

When creating a preform in which a reinforcing fiber base is wound around a core length of a wing-shaped hollow structure having a straight portion at least part of the cross section, the following formula is satisfied. A method for producing FRP, characterized in that a preform having a controlled winding tension is prepared, and RTM molding is performed while applying an internal pressure to the preform.
100 * {X− (Y + Z)} / Z = A (A ≦ 0) (1)
0.3 ≦ | A | <0.7 (2)
In the formula, X: chord length dimension after winding the reinforcing fiber Y: thickness of the wound reinforcing fiber substrate Z: chord length dimension of the core alone   The manufacturing method of FRP of Claim 1 which uses the reinforcing fiber whose tensile elastic modulus of a reinforcing fiber base material is 50 GPa or more.   The FRP manufacturing method according to claim 1 or 2, wherein the core material has a flexural modulus of 300 to 10,000 MPa.   The method for producing FRP according to any one of claims 1 to 3, wherein the thickness is a core of 0.6 to 4.0 mm.   The FRP manufacturing method according to claim 1, wherein the core is removed from the FRP body after the internal pressure molding.   The method for producing FRP according to claim 1, wherein the core material has releasability from the matrix resin.   The FRP manufacturing method according to claim 1, wherein a core having at least one opening is used.   The method for producing FRP according to any one of claims 1 to 7, wherein a core of a thermoplastic resin material is used.   The FRP manufacturing method according to any one of claims 1 to 8, wherein a blow-molded core is used.

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