JPS6129254B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a composite pipe with excellent corrosion resistance.

In recent years, composite pipes with a sanderch structure, in which an intermediate layer such as resin mortar is provided between the inner and outer reinforced resin layers reinforced with long glass fibers, have been used for large-diameter sewer pipes, etc. However, the quality of the water flowing down the sewer system is extremely poor depending on the location, such as domestic wastewater and some industrial wastewater, and on the other hand, glass fiber has poor chemical resistance, especially alkali resistance, and has poor acid resistance. If there are pinholes or cracks leading to the long glass fibers on the inner surface of the composite pipe, the flowing water will penetrate around the long glass fibers, causing the long glass fibers to become continuous fibers. Because of this, deterioration progresses indefinitely, and the strength of the inner reinforced resin layer decreases significantly, resulting in the disadvantage that it may be damaged by external forces such as earth pressure.

For example, as in Japanese Patent Publication No. 47-16999, a glass chopped strand mat is lined with glass cloth or a net-like material on top of a corrosion-resistant layer made of glass non-woven fabric or organic fiber non-woven fabric and resin, and tension is applied. Corrosion-resistant composite tubes are sometimes manufactured by winding the filament over the filament winding.

However, the method described above is not only complicated as it requires the preparation of chopped strand pine with a lining process, but also requires that the chopped strand pine be completely removed while being impregnated with resin during production. The disadvantages were that it was difficult to form bubbles, many pinholes were generated, and drainage water entered and deteriorated the glass fibers in the filament winding layer.

The present invention was made with the aim of solving the above-mentioned conventional drawbacks, and the gist thereof is to provide a method for manufacturing a composite pipe in which a reinforced resin molding material is wound and cured on a core mold. A composite pipe is manufactured by forming an inner protective layer by degassing a strip containing a group of short fibers, a group of short fibers, and a resin, and then winding the resin around a core mold in a semi-hardened state after degassing it. It lies in the method.

As the nonwoven fabric used in the present invention, for example, a nonwoven fabric made of various inorganic or organic woven fibers such as glass fiber is used.

The short fibers used in the present invention include short fibers made of various inorganic or organic fibers such as glass fibers.

As the resin used in the present invention, for example, unsaturated polyester resin, epoxy resin, vinyl ester resin, etc. are used.

Hereinafter, the present invention will be explained by way of examples with reference to the drawings.

1 is a core type in which an endless steel belt is wound around a core, and is configured to rotate in the circumferential direction and move in the axial direction. While the steel belt rotates once in the circumferential direction, it moves in the axial direction by the width thereof. A mold release material 2 such as cellophane tape is wrapped around the core mold 1, and a band-shaped body 3 made of glass fiber nonwoven fabric impregnated with resin is wound thereon. A chopped glass fiber strand 42 pre-impregnated with resin is spread on a glass fiber nonwoven fabric 41,
This is sandwiched between forming rolls 5 and formed into a diamond shape while being defoamed, then sandwiched between a defoaming belt 6 to defoam, and then passed through a curing accelerator 7 to semi-cure the resin, which is then shaped into a belt-shaped body 4. It is wound over the body 3 to form the inner protective layer 3.

On the inner surface protective layer 8, a reinforced resin molding material 9' made of long glass fiber and resin is wound to form an inner surface reinforced resin layer 9, and a molding material 10' made of resin concrete or the like is supplied on top of the inner surface reinforced resin layer 9. A reinforced resin molding material 1 made of long glass fibers and resin is supplied from a device 13 to form an intermediate layer 10.
1' is wound to form an outer surface reinforced resin layer 11, and after passing them through a curing furnace 12 to integrally cure the whole, the core mold 1 is removed to obtain a composite tube provided with an inner surface protective layer 8. .

As mentioned above, the manufacturing method of the invention composite pipe is as follows: After degassing a strip containing a nonwoven fabric, a group of short fibers, and a resin by applying strong pressure, the resin is semi-hardened and then wound around a core mold. Since it forms an inner protective layer,
The inner protective layer is sufficiently degassed and has extremely few pinholes, and is semi-cured in advance so that there will be no cracks when the whole is cured as a single piece.
It effectively blocks water in the composite pipe and does not deteriorate the reinforcing material in the inner surface reinforced resin layer, and even if water enters the inner surface protective layer through some pinholes, the short fiber group is a continuous fiber. Therefore, the inner protective layer does not deteriorate indefinitely and the inner protective layer does not deteriorate rapidly.

[Brief explanation of the drawing]

Fig. 1 is a front view illustrating an embodiment of the present invention, Fig. 2 is a vertical sectional side view taken along the line - - of the embodiment of Fig. 1 of the present invention, and Fig. 3 is an example of a composite pipe manufactured according to the present invention. FIG. Explanation of symbols, 1... core type, 3, 4... band-shaped body,
5... Forming roll, 6... Defoaming belt, 7... Curing accelerator, 8... Inner surface protective layer, 9... Inner surface reinforced resin layer, 10... Intermediate layer, 11... Outer surface reinforced resin layer.

Claims (1)

[Claims] 1. In a method of manufacturing a composite pipe in which a reinforced resin molding material is wound around a core mold and cured, a belt-shaped body containing a nonwoven fabric, a short woven fiber group, and a resin is degassed by strong pressure, and then the resin is semi-cured. A method for manufacturing a composite pipe, which comprises winding the pipe onto a core to form an inner protective layer.