JPH0119337B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a fiber-reinforced resin pipe using a thermosetting resin such as a polyester resin or an epoxy resin, and reinforcing fibers such as glass fiber or carbon fiber. The present invention relates to a method of manufacturing a fiber-reinforced resin pipe provided with a composite layer, such as a composite layer of metal cylindrical coating layer formed by vertically attaching or wrapping a tape.

Recently, so-called FRP pipes, which are made of thermosetting resin reinforced with fibers, are lightweight and have strong mechanical strength.
Since it also has excellent chemical resistance, its application fields are gradually expanding, but its manufacturing method is generally as follows, as shown in FIG.

That is, a plastic tape 2 with good lubricity such as polyethylene terephthalate is placed on the mandrel 1.
A plurality of glass fibers passed through a separately provided thermosetting resin impregnating tank 3 such as polyester or epoxy are placed on top of the glass fibers vertically or horizontally.
Then, a glass fiber is wrapped 5 thereon, passed through a bath 6 impregnated with a thermosetting resin such as polyester or epoxy, and then a plastic tape 8 is wrapped _8-1 before and after the molding die 7. _8-2 is carried out to ensure sufficient impregnation with a thermosetting resin such as polyester or epoxy using the wrapping pressure of the plastic tape 8, and then taken up by a caterpillar traction device 9 and passed through a molding rubber die 10. The product was placed in a curing furnace 11 to harden the thermosetting resin to form a pipe, pulled out from the curing furnace 11, cut into predetermined lengths with a cutter 12, and removed from the mandrel to produce a product.

The biggest drawback of this method is that
Thermal curing of plastic requires a large curing furnace, and this curing method cannot increase production speed for continuous production.

The present invention has been made in view of the above-mentioned circumstances, and eliminates the conventionally used curing furnace, provides electrodes at a certain distance on the mandrel itself, and generates Joule heat by energizing the electrodes. This method uses this Joule heat to cure the thermosetting resin on the mandrel, thereby providing a new method that simplifies production equipment and increases production speed.

An embodiment of the present invention will now be described with reference to FIG. The figure shows a method for manufacturing a fiber-reinforced resin pipe with a water-blocking layer made of metal tape rolled into a tubular shape in the middle.A plastic tape 2 with good lubricity, such as polyethylene terephthalate, is placed vertically or horizontally on a heated mandrel 1. A glass fiber is wrapped around it 5, passed through a bath 6 impregnated with a thermosetting resin such as polyester or epoxy, and then a metal tape 13 such as lead tape, iron tape, stainless steel tape, etc. is vertically attached thereon. , after forming into a circular shape with a former 14, the abutting portions are welded or soldered together 15.
The tube is then wrapped with glass fiber 5 and passed through a bath 6 impregnated with a thermosetting resin such as polyester or epoxy.The tube is then passed through a molding die 7 to form a smooth surface and covered with plastic tape 8. Winding 8
- ₁ and unwinding 8 - ₂ to apply pressure for winding and towing with the caterpillar traction device 9. In the embodiment, the well-known nipple molding method was used for molding with the former 14, but other well-known methods such as roll molding and belt molding may also be used. In addition,
For example, the hollow mandrel is provided with electrodes on the rear end 16a and the inner surface of its tip (not shown), and a lead wire 16 introduced into the inner cavity of the hollow mandrel is connected between these two electrodes and energized. The thermosetting resin such as polyester resin or epoxy resin is cured by this Joule heat, and a complete resin layer is formed.

The pipe thus produced is cut into predetermined lengths by a cutter 12 to produce products.

In the above description, a case in which a metal tape is vertically attached in the middle is shown, but of course the same can be applied to a simple fiber-reinforced resin pipe without this. Furthermore, although the case of reinforcement with glass fibers has been described above, it can be implemented in exactly the same manner with carbon fibers or the like.

As described above, the present invention has the advantage that pipes can be manufactured continuously by winding fibers and impregnating resin by using electric heating of a mandrel without requiring a curing tank as a means for curing the resin. It is.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a conventional fiber-reinforced resin pipe manufacturing line, and FIG. 2 is an explanatory diagram of a composite pipe manufacturing line of the present invention. 1: Mandrel, 2: Plastic tape with good lubricity, 5: Wrapping of glass fiber, 6: Thermosetting resin impregnation tank, 7: Molding die, 9: Caterpillar traction device, 12: Cutter, 13: Metal tape,
14: Former, 16a: Rear end of mandrel, 16b: Connection with lead wire, 16: Lead wire.

Claims (1)

[Claims] 1. A lubricating coating layer is provided on the rod-shaped hollow mandrel, on which reinforcing fibers are wound and thermosetting resin is impregnated. The electrodes were connected by a lead wire introduced into the inner cavity of the hollow mandrel, and electricity was applied to the lead wire to heat the hollow mandrel, and the thermosetting resin was cured by this heat to form a pipe. A method for manufacturing a fiber-reinforced resin pipe.