JPH0124063B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lightweight fiber-reinforced plastics tubular body having a sandwich structure, particularly an intermediate for forming a tubular body useful for making a curved pipe.
Fiber-reinforced plastic tubular bodies are used not only in straight tubular bodies such as golf club shafts and fishing rods, but also in tone arms of record players, bent arm shafts of golf putter clubs, racket frames, and pipe materials for chairs. Its use as a tubular body with bent arms is progressing.

Such a fiber-reinforced plastic tubular body,
Intermediates for forming tubular objects, which are particularly effective in the method of manufacturing bent pipes, are already known.

An object of the present invention is to develop an intermediate body for forming a tubular article that is lightweight and useful for forming a bent pipe made of reinforced plastics having a sandwich structure with high vibration damping properties.

Conventionally, in internal pressure molding of fiber-reinforced plastics using flexible pressure tubes such as rubber tubes, methods have been used such as filling the hollow part with foamed resin after molding to create a sandwich structure. Alternatively, fiber-reinforced plastics have been molded using the foaming pressure of foamable resin. However, no tubular bodies with a sandwich structure formed by internal pressure forming, especially curved pipes, have been found.

Therefore, the present inventors conducted research with the aim of obtaining a molded body having a hollow irregular cross section that has excellent vibration damping properties, is lightweight, and has a Sanderch structure, and completed the present invention.

That is, the present invention is characterized by forming a tubular product in which a matrix resin layer containing hollow spheres made of an inorganic organic substance or particles made of a foamed resin is formed on the outside of a pressurizing tube as the innermost layer. Intermediate for use. The filler to be used can be of any shape and size as long as it has a diameter that does not pass through gaps such as the weave and intersects of the reinforcing fiber tubular body. When making a hollow curved tube with a sandwich structure using such a molding intermediate, the intermediate is first placed in a pre-heated mold, and a high-pressure gas is injected into the pressurizing tube. The reinforcing fiber layer is impregnated with matrix resin.
At this time, the filler contained in the matrix resin layer cannot pass through the reinforcing fiber layer, so only the matrix resin is filtered out, and the matrix that fills in between the filler and filler particles is formed at the interface of the reinforcing fiber layer/matrix resin layer. A core material layer made of resin is formed.
The resin-impregnated fiber-reinforced tubular body layer is pressed against the inner wall surface of the mold, and by continuing to heat and pressurize it, it is possible to create a fiber-reinforced plastics tubular body with a sandwich structure having a predetermined irregular cross-sectional shape. . After molding, the molded body is removed from the mold, and the pressurizing tube such as a rubber tube is further removed to obtain a molded body. As the pressurizing tube used in the present invention, various rubber tubes made of natural rubber or artificial rubber, or plastic film tubes made of polypropylene, polyester, nylon resin, etc. can be used. Various materials can be used for the matrix resin layer used in carrying out the present invention, but one made of a material with low tackiness at room temperature is preferred. Such a matrix resin may be a thermosetting resin that is semi-molten at room temperature, and examples of the resin include epoxy resins, unsaturated polyester resins, phenote resins, and polyimide resins.

Furthermore, thermoplastic resins such as polyamide resins, acrylonitrile, butadiene, styrene resins, and polybutylene terephthalate resins can also be used. In addition, in the case of internal pressure molding, the matrix resin is easy to flow until it hardens after impregnating the reinforcing fiber tubular layer, and the resin flows out from the gap in the mold under pressurized conditions, so the matrix resin cannot be used as a fiber. The viscosity is preferably 50 to 500 poise at the gel point, which is sufficient for impregnation.
By making this matrix resin layer less sticky at room temperature, it becomes extremely easy to form the fiber-reinforced tubular layer to be laminated on the matrix resin layer, and in particular, the braiding of the fibers in the fiber-reinforced tubular layer becomes easier. This can be carried out without any trouble occurring due to the tackiness of the matrix resin. Furthermore, when the tubular product molding intermediate produced by such a method is installed in a mold, the adhesion of the matrix resin and the reinforcing fiber tubular material layer and the adhesion of the molding intermediate to the mold wall surface are avoided. Therefore, there is no reduction in the droop properties of the fiber tubular body, and it can be installed without causing any inconvenient phenomena such as bending wrinkles, making it possible to create a molded body that fully utilizes the characteristics of the reinforcing fiber. . As fillers used in the present invention, hollow spheres made of inorganic materials such as glass beads, shirasu balloons, and carbon balloons, hollow spheres made of plastic resins such as phenolic resins, or particles made of polyurethane, acrylic, and epoxy foam resins may also be used. Can be done. This filler may be used directly mixed with the matrix resin. It is possible to use a film-like material made of a matrix resin in which the filler is evenly scattered, or a film made of the filler in the form of a sandwich. As for the cross-sectional shape of the molding intermediate, as shown in Figure 1a, the matrix resin layer containing the filler is formed on the outside of the pressurizing tube, and as shown in Figure 1b, the matrix resin layer is formed between the layers of the reinforcing fiber tubular body. There are two possible ways to form it.

The reinforcing fiber tubular body can be formed by using conventionally developed braided tubular bodies, sheet-like or tape-like fabrics, knitted fabrics wound into a tubular shape, filament, and winding methods to efficiently exhibit the characteristics of the reinforcing fibers. It can be braided into a structure, but of course other methods are possible.

Examples of reinforcing fibers used in carrying out the present invention include inorganic fibers such as carbon fiber, graphite fiber, glass fiber, silicone carbide fiber, boron fiber, and alumina fiber, and organic fibers such as aromatic polyamide fiber and high modulus polyester fiber. Various fibers can be used.

In the tubular product forming intermediate of the present invention, the pressurizing tube can be easily removed from the molded product after molding. Furthermore, since the matrix resin does not adhere to the pressure tube or the reinforcing fibers, another major feature is that folding wrinkles do not occur when this molding intermediate is installed in a mold.

Furthermore, since the reinforcing fibers are not impregnated with matrix resin, and the matrix resin is made to flow into the fibers, the resin can be sufficiently filled into the gaps between the interwoven fibers of the woven fabric, knitted fabric, or braid on the outer surface. It is extremely easy to form a smooth and shiny reinforcing fiber layer.

To make a molded product using the tubular product molding intermediate of the present invention, a matrix resin film 3 containing a filler 6 as shown in Figure 2a or a matrix resin film 3 containing a filler 6 as shown in Figure 2b is used.
As shown in Figure 2c, fillers may be uniformly scattered on a sticky matrix resin film, or fillers may be sandwiched with a matrix resin film as shown in Figure 2c.

The matrix resin film containing this filler is wrapped around the outside of the pressurizing tube 2 into which the core 1 has been inserted as shown in Figure 1a, or a reinforcing fiber tubular layer 4 is formed on the outside thereof, or As shown in FIG. 2, a matrix resin layer is formed on the outside of the pressurizing tube 2 into which the core body 1 is inserted by sandwiching it with a reinforcing fiber tubular layer. After installing this in the mold, the mold is closed and a high-pressure gas is injected into the pressurizing tube, which pressurizes and heats the mold to start the flow of the matrix resin, and the reinforcing fiber tubular layer is placed inside the mold. It is pressed against a wall surface and the matrix resin is cured to obtain a molded body.

[Brief explanation of drawings]

Figure 1a shows a perspective view of an intermediate for forming a tubular object. Figures 1b and 1c show its A-A' cross-sectional shape. DESCRIPTION OF SYMBOLS 1... Core body, 2... Pressure tube, 3... Matrix resin film containing filler, 4... Reinforcing fiber tubular body layer, 5... Matrix resin layer, 6
...Filling material. Figure 2 shows a perspective view of a matrix resin film or sheet with a filler attached.

Claims (1)

[Claims] 1 The innermost layer has a pressurizing tube, and is composed of a matrix resin layer to which a low-density filler such as hollow spheres made of inorganic or organic materials or foamed plastic particles is attached or included, and a reinforcing fiber tubular layer. An intermediate for forming tubular objects.