JPH03277532A - Production of bent pipe made of fiber reinforced plastic - Google Patents

Abstract

PURPOSE:To obtain the above product which is little in deformation due to molding and little in generation of bubbles without mold-releasing a hollow mandrel by laminating fiber reinforced resin composite material on the freely bendable coillike or bladelike hollow mandrel and forming it and fitting the formed body to a mold while the hollow mandrel is inserted thereinto and expanding it by pressurized fluid and performing heating and curing treatment. CONSTITUTION:A utilized coillike or bladelike hollow mandrel is made freely bendable in order to form the fiber reinforced resin composite material 2 into a bent pipe. Further, a gap part is provided in a range over the whole length in order to pass the compressed air and to allow it to act on the inner face of the said composite material 2. A silicone rubber layer 4 is inserted into this hollow mandrel 1. Furthermore, a mold release film 3 is inserted as a mold release layer. A carbon fiber-unidirectional prepreg is wound and laminated thereon. This is fitted to a mold 5 and compressed air is supplied through a nozzle 8. Thereby expansion and thermal curing treatment are performed on the fiber reinforced resin composite material 2.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a method for manufacturing a fiber-reinforced plastic curved pipe, in particular, a method for manufacturing a fiber-reinforced plastic bent pipe, in which a core bar is attached to a fiber-reinforced resin composite material before the fiber-reinforced resin composite material is installed in a mold. The present invention relates to a method for manufacturing a fiber-reinforced plastic curved pipe that does not require release from the mold.

(Prior Art) As a conventional method for manufacturing fiber-reinforced plastic curved pipes, there is a known method in which a rubber elastic tubular body is used as a molding core corresponding to a mold (Japanese Patent Publication No. 63-21607, Japanese Patent Publication No. 63-21607,
-21608 Publications 1゜In addition, as another method, a method is known in which a solid body or hollow body made of steel or the like is used as a core mold corresponding to a mold (vF 64-78825
Publication No.).

(Intelligence problem to be solved by the invention) In the former method, a rubber elastic tubular body wrapped with fiber prepreg is molded into a curved tube and attached to a mold, but the rubber elastic tubular body is used as a molding core. Because of this, it is not possible to apply sufficient pressure when winding the fiber prepreg around the rubber elastic tubular body, and air bubbles tend to form.

In the latter case, a core material through which a core mold is inserted is wound with an FRP layer, then an outer cover is covered, the core mold is removed, and the core material is set in a shape-retaining mold.

It is time-consuming to release the mold while it is uncured, and it may become deformed since the tube is formed after the mold is released.

The present invention provides a method for mounting a fiber-reinforced resin composite material into a mold without releasing the core metal inserted during lamination molding of the fiber-reinforced resin composite material (also, since there is less deformation due to molding and no air bubbles are generated). It is an object of the present invention to provide a method for manufacturing a fiber-reinforced plastic curved pipe that can produce a product with a low amount of carbon dioxide with high productivity.

(Means for Solving the Problems) The present invention has been made to achieve the above object, and is a method in which a fiber-reinforced resin composite material is laminated and molded on a freely bendable hollow core bar, and the hollow core bar is inserted into the core bar. The fiber-reinforced resin composite material is molded into a bent tube and installed in a mold, and the pressurized fluid is fed into the mold and acts on the inner surface of the fiber-reinforced resin composite material through the gap in the hollow core metal to create the fiber-reinforced resin composite material. The present invention relates to a method for manufacturing a fiber-reinforced plastic curved pipe, which comprises expanding the fiber-reinforced resin composite material and then subjecting the fiber-reinforced resin composite material to a heat curing treatment.

The present invention will be explained in more detail below.

As the fiber reinforced resin composite material used in the present invention, glass prepreg, carbon fiber unidirectional prepreg, carbon fiber cloth prepreg, aramid fiber cloth prepreg, etc. are used.

This fiber-reinforced resin composite material is wound around a hollow core metal and laminated and molded.

The laminated and molded fiber-reinforced resin composite material is subjected to bending according to the shape of the product with the hollow core metal inserted therein. Therefore, the hollow core metal used is one that is flexible.

After the fiber-reinforced resin composite material is mounted on the mold, a pressurized fluid that acts on the fiber-reinforced resin composite material is fed into the mold along the hollow core bar.

However, the pressurized fluid does not act on the fiber-reinforced resin composite material through the hollow core metal, but acts on the inner surface of the fiber-reinforced resin composite material through the gap in the hollow core metal.

A coil-shaped or a blade-shaped hollow core metal is suitable as such a hollow core metal. These molds have strength, are flexible, and have a gap.

In the present invention, the inner surface of the fiber-reinforced resin composite material is separated from the composite core metal due to the action of the pressurized fluid.

In particular, by pulling one end of a coiled hollow core metal, the diameter of the coil is reduced.

Therefore, even without providing a release layer such as a release film,
The hollow core metal can be taken out from the mold.

Furthermore, since the hollow core metal has a gap, a silicone rubber layer may be interposed therebetween.

After expanding the fiber-reinforced resin composite material with a pressurized fluid, it is subjected to heat curing treatment. As for the heating method, the mold is placed in a curing furnace and heated, and in order to prevent uneven heating, a heating wire is passed through the hollow core metal and the core metal itself can be heated by applying electricity. This can promote the hardening reaction of the inner surface.

[For production]

The hollow core metal in the present invention has a gap, and the pressurized fluid comes into contact with the inner surface of the fiber-reinforced resin composite directly or via a silicone rubber layer or the like through the gap.

Therefore, the hollow core metal does not provide any resistance to the pressurized fluid acting on the fiber reinforced resin composite.

(Example) An example of the present invention will be described with reference to FIGS. 1 to 4.

FIG. 1 shows a fiber-reinforced resin composite material 2 laminated and molded onto a bendable hollow core metal 1.

Here, the hollow core metal 1 used was a coil-shaped one made of spring steel as shown in FIG. 2A, and a blade-shaped one as shown in FIG. Both are bendable in order to form the hollow core metal fiber reinforced resin composite material 2 into a curved tube, and have a gap over the entire length for allowing compressed air to pass through and act on the inner surface of the fiber reinforced resin composite material 2. have Figure 3a,
When laminated as a resin composite material 2 in Fig. 3, a silicone rubber layer 4 is inserted into the inner metal core 1, a release film 3 is further inserted as a release layer, and carbon fibers are inserted from the upper blade. Unidirectional prepreg ta! 1 The case where the reinforced resin composite material 2 is wound and laminated is shown. 1 The fiber reinforced resin composite material 2 in such a state is mounted in a mold 5 as shown in FIG.
(2) Compressed air was supplied through the nozzle 8 to expand and heat-cure the fiber reinforced resin composite material 2. The mold 5 consists of an upper mold 6 and a lower mold 7 that can be opened and closed. 9 indicates an air outlet.

By this method, it was possible to produce a fiber-reinforced plastic curved pipe with fewer bubbles and fewer wrinkles.

(Effects of the Invention) According to the present invention, a curved pipe made of fiber-reinforced plastic can be finished with fewer bubbles and fewer wrinkles.

In addition, it can be manufactured without inserting or removing the core metal during manufacturing.
It is extremely practical as it can contribute to improving productivity.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an example of a fiber-reinforced resin composite material in which a hollow core metal according to the present invention is inserted; 3A and 3A are views showing an example of the cross section taken along the line A-A in FIG. 1, and FIG. 4 is a view showing an example of a mold used in carrying out the present invention. 1... Hollow core bar, 2... Fiber reinforced resin composite material, 5...
··Mold. Figure/-A Figure 2 a Figure 2 Figure 3 q Figure 3 Figure 3

Claims (2)

[Claims] (1) A fiber-reinforced resin composite material is laminated and molded onto a freely bendable hollow core metal, and the fiber-reinforced resin composite material is molded into a bent pipe with the hollow core metal inserted inside, and the fiber-reinforced resin composite material is attached to a mold. The fiber-reinforced resin composite material is expanded by a pressurized fluid that is fed into the core and acts on the inner surface of the fiber-reinforced resin composite material through the gap of the hollow core metal, and then the fiber-reinforced resin composite material is subjected to a heat curing treatment. A method for producing a fiber-reinforced plastic curved pipe. (2) The method for manufacturing a fiber-reinforced plastic curved pipe according to claim 1, wherein the hollow core metal is formed into a coil shape or a blade shape.