JPH0112658B2 - - Google Patents

Description

Detailed Description of the Invention The present invention uses thermosetting resins such as polyester resins and epoxy resins, reinforcing fibers such as glass fibers and carbon fibers, and reinforcing metal coatings such as iron tape, lead tape, and stainless steel tape. The present invention relates to a method for manufacturing a composite pipe.

Recently, composite pipes made by reinforcing thermosetting plastic with fibers and forming a barrier layer by rolling metal tape into a circular tube shape as an intermediate layer have become water-resistant, chemical-resistant, termite-proof, rodent-proof, etc. It is a pipe that is promising as a pipe that can be buried underground and store cables, etc., because it is strong enough to withstand rockfalls, impacts, etc., and is relatively lightweight. I found out.

By the way, the conventional method for manufacturing a fiber reinforced pipe made of thermosetting resin is as shown in FIG. A plurality of glass fibers passed through a separate bath 3 for impregnating a thermosetting resin such as polyester or epoxy are longitudinally attached 4, and further glass fibers are wrapped around the fibers 5, and a thermosetting resin such as polyester or epoxy is applied. The plastic is passed through an impregnating tank 6, and then a plastic tape 8 is wound _8-1 and unwound _8-2 before and after the molding die 7 to impregnate the plastic with a thermosetting resin such as polyester or epoxy. Make sure that the winding pressure of the tape 8 is sufficient, and then turn the caterpillar traction device 9 on.
The product was taken up by a molding rubber die 10, put into a curing furnace 11, cured the thermosetting resin, and pulled out of the curing furnace 11, cut into predetermined lengths with a cutter 12, and removed the pipe from the mandrel to produce a product. It is something.

The biggest disadvantage of this method is that it requires a large curing furnace to heat-cure the plastic, and that it is difficult to increase production speed for continuous production. It had its flaws.

The present invention was made in view of the above-mentioned circumstances, and it eliminates the conventionally used curing furnace and uses a resistant metal tape such as lead, iron, or stainless steel as the metal tape, and wraps it around the metal tape. Electricity is passed between the starting point and a certain point after wrapping, and the generated Joule heat is used to harden the thermosetting resin impregnated layer, making the production equipment simpler than before. The present invention provides a method that can be carried out at a much faster manufacturing speed than conventional methods, improves the manufacturing efficiency of the composite pipe product, and contributes to cost reduction.

Now, referring to FIG. 2, the present invention will be described. On a mandrel 1, a highly slippery plastic tape 2 such as polyethylene terephthalate is vertically or horizontally wound, and a glass fiber is wound thereon 5.
After passing through a bath 6 impregnated with a thermosetting resin such as polyester or epoxy, a resistive metal tape 13 such as lead tape, iron tape, or stainless steel tape is applied thereon.
The former 14 is attached vertically and formed by a well-known nipple molding method, roll molding method or belt molding method.
After molding, the abutted portions are welded or soldered 15 to form a circular tube, and glass fiber is again wrapped 5 thereon and passed through a bath 6 impregnated with a thermosetting resin such as polyester or epoxy. , the glass fibers are passed through a molding die 7 to improve the adhesion between the glass fibers and the metal circular tube, and the surface is formed to be smooth, and the product is towed by a caterpillar traction device 9.

The characteristic feature of the present invention is that a resistive metal tape 13 is attached vertically, and one end of the electrode is attached to the first point 13-a of the resistive metal tape 13. Clamp the electrode at the other end at point 13-b, run the electrode at 13-b together with the pipe, release it at point 13-c just in front of the caterpillar traction device 9, and apply a current between the two electrodes. By flowing the resin, Joule heat is generated, and the impregnated thermosetting resin is cured by this heat.

In step 13-b, the glass fiber in the part where the electrode is clamped is made rough by changing the take-up speed or number of rotations to create a gap and then clamp the electrode, so that the electrode becomes a metal circle. Conducts with the pipe. Although the above description has been made using glass fiber as an example, carbon fiber can also be used in the same manner. The composite pipe completed in this way is cutter 12.
The cut is made at the portion where the above-mentioned gap is created for each predetermined length.

As mentioned above, the present invention is relatively simple, does not require large-scale heating equipment, and has excellent manufacturing efficiency, and the composite pipe obtained by this method is a composite pipe of fiber-reinforced thermosetting resin and metal. By configuring this metal as a metal tube in the middle part,
It is completely waterproof, and the metal itself is rust-proof and has excellent water resistance, chemical resistance, and termite resistance.It also has strong mechanical strength, and when used as a pipe to store cables, etc. It has excellent performance and can be omitted.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a conventional glass fiber-reinforced thermosetting 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 slipperiness, 5... Glass fiber wrapping, 6... Thermosetting resin impregnated layer, 7... Molding die, 9... Caterpillar traction device, 12... Cutter , 13...
Resistive metal tape, 13-a... At the beginning of vertical alignment, 13-b... At the electrode clamp immediately after passing through the impregnating tank, 13-c... At the release point of the electrode clamp, 1
4... Former, 15... Welding or solder joint.

Claims (1)

[Claims] 1 Wrap reinforcing fibers and impregnate thermosetting resin on the lubricious coating layer on the mandrel,
A resistive metal tape is longitudinally spliced and coated, further wrapped with reinforcing fibers and impregnated with thermosetting resin. A method for manufacturing a composite pipe, characterized in that the thermosetting resin is heated and cured by applying electricity between the pipe and an electrode that moves at a constant interval after exiting a die.