JP2002337244A - Method for manufacturing frp cylinder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing an FRP cylinder no which creases are hardly generated, when the cylinder is molded by a VaRTM process. SOLUTION: A reinforcing fiber 2 is laminated on the surface of a molding die of a cylindrical shape 1 and a resin-diffused medium 3 made of a metal netting is arranged on the reinforcing fiber 2. After that, the medium 3 is covered with a film 6 and the inside of the film 6 is set at a lower pressure of not more than 0.6 torr than the atmospheric pressure. Finally, a resin is injected using a pressure difference so that the reinforcing fiber is impregnated with the resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a method for manufacturing an FRP cylinder.

[0002]

2. Description of the Related Art Conventionally, various types of cylindrical FRPs have been considered, and many applications have been developed.
For example, it is a drive shaft of an automobile, a golf shaft, a fishing rod, or the like. There are various molding methods, such as a filament winding method in which a fiber bundle is wound around a mandrel while impregnating with a resin, and a method in which a prepreg is wound around a mandrel. And
Recently, large-diameter FRP cylinders having a diameter exceeding 500 mm have been used for applications such as large-diameter petroleum pipelines and chimneys, and have been spotlighted from the viewpoint of ease of construction and corrosion resistance due to weight reduction.

However, in the case of a large-diameter cylinder having a diameter exceeding 500 mm, the production efficiency is very poor if the prepreg is wound on the mandrel one by one in the method of winding the prepreg around the mandrel. Also, when forming by the filament winding method, it is necessary to rotate a very large mandrel with high precision, and a large and precise device is required to realize such a thing, so that the forming cost is very high. There was a drawback that it would be higher.

On the other hand, as is well known, in the recent molding industry, RTM molding (Vacuum Asisted Resin Transfer Molding: VaRTM method) using vacuum pressure for molding various FRPs.
Has been used. Unlike the ordinary RTM method, the VaRTM method has the advantage that a large-sized molding device is not required because the resin is impregnated only by vacuum pressure. Also, in order to facilitate resin impregnation, a molding method using a resin diffusion medium of a net-like or knitted or woven fabric formed from a plastic monofilament as shown in U.S. Pat.No. 4,902,215 has been proposed. It is a very useful molding method.

[0005] However, this method is applied to a cylindrical FRP.
When used for molding, the reinforcing fiber is laminated on the outer surface using a cylindrical mold, and the resin is injected while the inside is in a vacuum state. There is a problem that wrinkles are formed, and only a molded article having very low design and physical properties can be obtained.

When laminating reinforcing fibers, it is very difficult to increase the tension of the reinforcing fibers in order to prevent wrinkles from occurring. Since the reinforcing fibers shrink in the circumferential direction inside the film to provide a margin, it is inevitable to generate wrinkles.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for manufacturing an FRP cylinder which is less likely to cause wrinkles when forming the FRP cylinder by the VaRTM method. is there.

[0008]

In order to solve the above problems, the present invention has the following constitution.

[0009] Reinforcing fibers are laminated on the surface of a cylindrical mold, and a resin diffusion medium composed of a metal net is disposed on the reinforcing fibers, and then covered with a film. By using the pressure difference, a resin is injected into and impregnated into the reinforcing fiber.
Manufacturing method of RP cylinder.

In such a method of manufacturing an FRP cylinder, the metal net is not particularly limited in its material and woven structure, but the wire constituting the metal net has a diameter of 0.5 mm or more and 2 mm or less. It is preferable that the mesh in this case is 10 mm or less.

In the present invention, the reason why the reinforcing fibers are laminated on the surface of the cylindrical mold and the net-like resin diffusion medium is disposed thereon is that when the film is subsequently covered with a film and evacuated, the reinforcing fiber is reinforced. The wrinkles generated due to the margin due to the circumferential shrinkage of the fibers are prevented by pressing down the metal surface with an appropriate pressing force by this metal net, and the resin flows evenly inside the net in the circumferential direction of the die In order to form a flow path. Therefore, it is necessary that the metal net has considerable rigidity as a whole and does not hinder the flow of the resin. In this case, the rigidity of the metal net is a function of the wire diameter of the wire constituting the metal net and the mesh (mesh). Therefore, the stiffness increases as the wire gets thicker.
It is preferably from 0.5 mm to 2 mm, and more preferably from 0.5 mm to 1 mm from the viewpoint of resin fluidity. On the other hand, when wires of the same material are used for the mesh, the finer the mesh, the higher the rigidity. When using a wire in the above thickness range, the mesh is 1
If it is 0 mm or less, it will have sufficient power to suppress the reinforcing fibers.

As the matrix resin of the FRP cylinder,
Although not particularly limited, a thermosetting resin is preferable from the viewpoint of heat resistance and physical properties of the FRP after molding. As the thermosetting resin, a vinyl ester resin, a polyester resin, an epoxy resin, a phenol resin, or the like that is usually used for molding FRP can be used.

The reinforcing fiber of the FRP cylinder is not particularly limited, such as carbon fiber, glass fiber, and aramid fiber. In order to exhibit lighter weight and higher physical properties, it is more preferable to use carbon fiber. Considering the lower cost, it is most preferable to use so-called large tow carbon fibers. Specifically, the number of filaments of one carbon fiber yarn is not less than ordinary 10,000, but is in the range of 10,000 to 300,000, more preferably 50,000 to 150,000. It is preferable to use a certain tow-like carbon fiber filament yarn because it is more excellent in resin impregnation property, handleability as a reinforcing fiber base material, and economical efficiency of the reinforcing fiber base material. Further, it is more preferable to arrange a carbon fiber woven fabric on the surface of the FRP cylinder, that is, on the outer surface of the mold, because the design of the surface is enhanced. Further, in the production method of the present invention,
A polyester or nylon textile may be laid between the reinforcing fiber and the metal net. This textile is used to peel the metal net from the reinforcing fibers after molding. Generally, polyester and nylon textiles have poor adhesion to reinforcing fibers, so that the metal net can be peeled from the FRP by peeling the textile after resin injection and curing. In addition, in order to further improve the releasability of the textile, a textile whose surface is treated with fluorine is commercially available, and it can be used.

[0014] The mechanical strength of the FRP cylinder is determined as necessary or in accordance with required mechanical properties, etc., by forming a reinforcing fiber base material by laminating a plurality of layers of reinforcing fibers. The base material is impregnated with the resin. On the reinforcing fiber layer to be laminated, a fiber layer or a fabric layer aligned in one direction can be appropriately laminated, and the fiber orientation direction can be appropriately selected according to the direction of required strength.

As for the diameter of the FRP cylinder manufactured by the manufacturing method of the present invention, basically any outer diameter can be manufactured, but with a small diameter, the filament winding method described in the prior art can be used. The method of the present invention is not always the most suitable molding method because it can be efficiently produced by a prepreg method or the like. That is, since it is very difficult to efficiently form the cylinder when the diameter of the cylinder is 500 mm or more in the conventional FRP molding technique, the method of manufacturing the FRP cylinder of the present invention molds the one having an outer shape of 500 mm or more. It can be said that it is suitable for the case.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings in the order of manufacturing steps.

FIG. 1 is a longitudinal sectional view of an intermediate step for explaining a method of manufacturing an FRP cylinder according to the present invention, FIG. 2 is a sectional view showing a step subsequent to the step of FIG. 1, and FIG. The state of the process is shown in a perspective view.

First, when manufacturing the FRP cylinder of the present invention, preparation for molding described below is performed.

That is, in FIG. 1, a cylindrical mold 1 made of a material such as a metal or a thermosetting resin is used.
On the outer surface (solid inside), the laminated body 2 for the above-mentioned reinforcing fiber is formed, and the resin diffusion medium 3 made of a metal net is disposed thereon.

As the reinforcing fiber laminate 2, it is extremely time-consuming to laminate only the fibers. Therefore, it is more efficient to laminate the reinforcing fibers after forming the reinforcing fibers in a woven form in advance. For woven fabrics, one reinforcing fiber is required depending on the direction of the required rigidity.
One that uses synthetic fibers as the weft,
Depending on the application and required mechanical properties, it is possible to use a woven fabric in which the reinforcing fibers are formed in two directions (usually 0 ° / 90 °) or a so-called multiaxial woven fabric in which reinforcing fibers are arranged also in the 45 ° direction. preferable.

On the other hand, as the resin diffusion medium 3, a metal net is arranged so as to surround the circumference after laminating reinforcing fibers.

Next, as shown in FIGS. 2 and 3, a metal net 3 is arranged on the laminate 2 described with reference to FIG. 1, and the periphery thereof is evenly surrounded. A resin injection port 4 is provided on the outer peripheral surface.
A and 4B are divided and arranged at several places in consideration of the resin injection amount, and the vacuum suction port 5 is provided at a position facing these resin injection ports.
And fix it by appropriate means. In the present embodiment, as shown in FIG. 2, a total of three injection ports 4A and 4B each having an opening in the direction of the mold 1 are shifted by 90 degrees in the circumferential direction of the mold 1 to form Ω-shaped injection ports 4A and 4B. The vacuum line is arranged so that its axis coincides with the axial direction of the mold, and two vacuum suction ports 5 having the same structure as the injection ports 4A and 4B are brought close to the opposing position. 1 are arranged in the axial direction. The resin and the vacuum suction direction are one direction in the direction of the arrow in FIG. 3, but may be from both directions of the injection ports 4A and 4B and the suction port 5 according to the resin injection or the displacement of the internal air. In addition, although the cross-sectional shapes of the injection ports 4A and 4B and the suction port 5 are all Ω-shaped, holes of equal pitch or unequal pitch may be provided in the longitudinal direction according to the amount of injection or displacement. Finally, the whole is covered with the film 6. As the film, it is preferable to use a transparent film in order to check the flow state of the injected resin inside.

As described above, when the molding preparation of the present invention is completed, the following molding step is performed. In addition, the following is an example and is not limited to this.

A hose (not shown) is drawn out of the film 6 from the vacuum suction port 5 and connected to a vacuum pump (not shown) to set the inside of the film 6 to a pressure lower than the atmospheric pressure of 0.6 torr or less.

A hose is drawn out of the film from the resin inlets 4A and 4B and connected to a resin tank (not shown). At this time, the hose is closed with a pinch cock or the like in advance.

After the inside of the film 6 has a sufficiently low pressure, the cock of the hose connected to the resin injection port 4A is first opened to start the resin injection. In this case, the resin flows through the resin diffusion medium 3 and first diffuses in the circumferential direction, and then sequentially impregnates the inside of the reinforcing fiber layer 2. Since a transparent film is used for the film 6 as shown in FIG. 3, it can be easily confirmed that the injected resin flows uniformly in both the circumferential and longitudinal directions of the mold 1.

When the resin flowing inside the metal net 3 reaches the injection slits of the next two resin injection ports 4B whose phases are shifted by 90 degrees, the cock of the hose connected to the resin injection port 4B is opened.

When the resin is sucked in the circumferential and longitudinal directions of the mold 1 and reaches the vacuum suction port 6, the suction is stopped.

After confirming the impregnation of the resin, the resin is cured by a usual operation.

After the resin has hardened, the vacuum pump is turned off,
The film 6 is removed and the mold 1 is released.

With the above, the manufacturing process of the present invention is completed.
Among the above molding methods, the vacuum suction port 5 or the resin injection port 4
It is preferable to change the number of the components according to the size of the molded product. When molding an FRP cylinder having a large diameter, it is necessary to increase the number of vacuum suction ports and resin injection ports to maintain an appropriate degree of vacuum and a resin supply amount. For example, although it depends on the lamination thickness of the reinforcing fibers 2, it is preferable to provide the resin injection ports 4A and 4B at intervals of 50 m to 1 m in the circumferential direction of the mold 1.

The temperature during molding is not particularly limited, but when molding a large FRP cylinder, a large heating oven is required for heat curing, so that the molding cost is increased. In such a case, it is preferable to use a resin curable at room temperature.

If the pressure in the film 6 is lower than the atmospheric pressure, it is possible to impregnate the resin by the pressure difference. However, in order to increase the impregnation speed of the resin and increase the molding efficiency, The pressure in the film is preferably set to 0.6 torr or less.

(Embodiment) According to the steps shown in FIGS.
Using a metal net having a wire diameter of 0.63 mm and a mesh of 3 mm as the resin diffusion medium 3, molding was performed by the VaRTM method. The FRP cylinder to be molded has a diameter of 600 mm, and is made of a vinyl ester resin curable at room temperature (manufactured by Dow Chemical Company, Deracane 401;
ps) was used.

As the reinforcing fiber 2, four layers of carbon fiber biaxial woven fabric (manufactured by Toray Co., Ltd .; basis weight 300 g / m ² ) were used. When the pressure in the film was adjusted to 0.3 torr by a vacuum pump, no wrinkles were found in the reinforcing fiber layer. The vinyl ester resin was injected at room temperature, and when all the resin was impregnated, the injection of the resin was stopped and the resin was cured. No wrinkles were observed on the surface of the reinforcing fiber layer even when the cured FRP was observed.

(Comparative Example) Molding was performed using the same configuration as in the above example except that a polyethylene net (manufactured by Nippon Netron Co., Ltd.) was used instead of the metal net. , Wrinkles were observed in the reinforcing fiber layer. In addition, wrinkles were observed on the surface of the reinforcing fiber layer in the observation of the molded product after resin injection and curing.

[0037]

According to the present invention, a reinforcing fiber is laminated on the surface of a cylindrical mold, a resin diffusion medium made of a metal net is disposed on the reinforcing fiber, and the whole is covered with a film. By making the inside of the film a pressure lower than the atmospheric pressure, the resin is injected into the reinforcing fibers by utilizing the pressure difference, and the method of manufacturing the FRP cylinder in which the resin is impregnated, so that the resin diffuses evenly into the reinforcing fibers. Thus, a wrinkle-free FRP cylinder can be manufactured.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view for explaining a production method of the present invention at a stage where a reinforcing fiber is laminated on a cylindrical mold and a resin diffusion medium is disposed thereon.

FIG. 2 is a cross-sectional view for explaining a manufacturing method of the present invention at a stage where a resin injection port, a vacuum suction port, and a film are arranged in FIG.

FIG. 3 is a perspective view of the molding method of FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Mold 2 ... Reinforcing fiber layer 3 ... Metal net (resin diffusion medium) 4 ... Resin injection port 5 ... Vacuum suction port 6 ... Film

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) B32B 27/04 B29K 105: 08 // B29K 101: 10 105: 22 105: 08 B29L 23:00 105: 22 B29C 67/14 BB29L 23:00 LF term (reference) 4F100 AB01B AD11A AK01A AK01B AK01C AK21 AK41C AK48C BA02 BA03 BA07 BA10A BA10B DA11 DG01B DG07B DG11A DG11C EJ13 EJ02E DH12B DH02A DH12B AA24 AA29 AA36 AC02 AC03 AD03 AD12 AD15 AD16 AD20 AD35 AG03 AG08 AH59 AM28 AM32 HA02 HA06 HA14 HA23 HA33 HA37 HA38 HA44 HA47 HB02 HB12 HC13 HC14 HC17 HF01 HF24 HF30 HK23 HL02 HM06 HT08 HT14 HT22

Claims (8)

[Claims] Claims: 1. A reinforcing fiber is laminated on the surface of a cylindrical mold, a resin diffusion medium made of a metal net is disposed on the reinforcing fiber, and then the whole is covered with a film.
A method for producing an FRP cylinder in which a resin is injected into and impregnated into the reinforcing fiber by making the inside of the film a pressure lower than the atmospheric pressure and utilizing the pressure difference. 2. The metal net has a wire diameter of 0.5.
2. The FRP according to claim 1, wherein the mesh is not less than 2 mm and not more than 2 mm, and the mesh (mesh size) of the net is not more than 10 mm.
A method of manufacturing a cylinder. 3. The method for producing an FRP cylinder according to claim 1, wherein a transparent film is used. 4. The method for producing a FRP cylinder according to claim 1, wherein a thermosetting resin is used as the matrix resin. 5. The method for producing an FRP cylinder according to claim 1, wherein the diameter of the FRP cylinder is 500 mm or more. 6. A carbon fiber as the reinforcing fiber.
6. The method for producing an FRP cylinder according to any one of items 1 to 5. 7. The method for producing an FRP cylinder according to claim 1, wherein a polyester or nylon textile is laid between the reinforcing fiber and the metal net. 8. The pressure lower than the atmospheric pressure is 0.6 to
The method for producing an FRP cylinder according to any one of claims 1 to 7, wherein a pressure of rr or less is used.