JPH079774B2 - Gas dam cable manufacturing method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to the adhesive strength between a dam-forming resin and the plastic coated core wire when forming a gas dam portion in a cable composed of a large number of plastic coated core wires such as electric wires and optical fibers. The present invention relates to an improvement of the plasma treatment in a method of manufacturing a gas dam cable in which the plastic coating surface is activated by gas plasma treatment to improve the temperature.

[Prior art]

Generally, the cable gas dam is formed by stripping off the sheath of the cable to expose a large number of plastic coated core wires and filling a filler such as epoxy or urethane across the exposed core wire and the sheath parts on both sides of the exposed core wire. To be done. However, in this case, since there is no adhesiveness between the filler and polyethylene, which is a material for the core wire coating, the sheath, etc., before the filler is filled for the purpose of improving the adhesiveness, the core wire exposed portion And the method of applying plasma treatment to the sheath on both sides (Japanese Patent Application No. 56-33)
No. 980) has already been proposed.

This method will be described with reference to FIG. FIG. 1 is a sectional view showing a state in which a part of a cable is plasma-processed by using a conventional plasma processing apparatus. When the gas dam portion is formed using this conventional apparatus, the sheath 2 of the portion of the cable 1 where the gas dam portion is to be formed is peeled off to expose a large number of plastic coated core wires. The core wire exposed portion 3 is inserted into the plasma processing container 4. The plasma processing container 4 has a container body 6 and a lid 8 provided at both ends via the container body 6 and an O-ring 7 for sealing and having a cable through hole in the center.
8 and. After the core wire exposed portion 3 is positioned substantially in the center of the plasma processing container 4, the gap between the cable through hole of the lid 8 at both ends and the cable 1 is sealed with a sealing tape 9. Then, the inside of the plasma container 4 is evacuated by the vacuum pump 11 through the suction pipe 10. When the evacuation is started, the active gas and the inert gas are then sent from the gas cylinder 15 through the delivery pipe 16 to the plasma processing container 4, and when the degree of vacuum inside the container 4 becomes stable, a high frequency generator
Gas plasma is generated in the plasma generator 18 by the gas generator 17. The gas plasma is introduced into the plasma processing container 4 through the delivery pipe 16 and activates the surfaces of the exposed portion 3 of the core wire and the sheath portions at both ends thereof.

However, in the conventional method in which the suction pipe 10 and the gas plasma delivery pipe 16 are opened in the approximate center of the plasma processing container 4 as shown in FIG. Since the plasma density was low in the parts F and F, the treatment was uneven and insufficient.

Generally, in a gas dam cable, gas is sealed in the upper side of the cable, that is, the A portion side in the cable 1 in FIG. Therefore, it is necessary to increase the gas plasma density and perform uniform plasma treatment at the portion E in FIG. However, as described above, the conventional method cannot sufficiently perform the plasma processing on the E portion at the end of the exposed portion of the core wire, and as a result, it takes a lot of processing time. Also, to solve this problem,
There is also a method of increasing the plasma generation amount by increasing the size of the plasma processing apparatus itself to increase the plasma density in the entire plasma processing container, but in this case, there is a problem that the cost of the apparatus increases.

[Object of the Invention]

In view of the above problems, an object of the present invention is to provide a method for manufacturing a gas dam cable in which a plasma density is increased and an efficient and uniform plasma treatment is applied to a portion where gas tightness is most needed. It is in.

[Structure of Invention]

In order to achieve the above object, the present invention peels off the sheath of the cable to expose a large number of plastic-coated core wires, and places the exposed core wires and the sheath portions on both sides thereof in a gas plasma processing apparatus. In the method for manufacturing a gas dam cable in which a gas dam portion is formed by filling a filler over the exposed core portion and the sheath portions on both sides thereof after the treatment, in the exposed core portion and the sheaths on both sides thereof. Among the above parts, the plasma density of the core wire exposed portion on the gas filled side requiring reliability of gas tightness and the sheath portion adjacent to the core wire exposed portion is made higher than that of other portions. .

Example of Invention

 Embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 2 is a sectional view of one embodiment according to the present invention, and FIG. 3 is a sectional view of another embodiment. As shown in FIG. 2, in the present invention, the core wire exposed portion 3 in which a large number of plastic-coated core wires are exposed by peeling off the sheath 2 at the portion where the gas dam portion of the cable 1 is formed is almost the same as the plasma processing container 4. Position in the center. Now, assuming that the gas-filled side of the cable 1 is the A side in FIG. 2, the most gas-tightness reliability is required at the E section. Therefore, the opening portion of the plasma delivery tube 16 is made to come to the E portion composed of the A side end of the core wire exposed portion 3 and the sheath portion adjacent thereto, and the opening portion of the suction pipe 10 for vacuuming is also the above-mentioned. Move to the E section side. In this case, the opening of the suction pipe 10 is made to face the opening of the delivery pipe 16, or slightly inward, that is, a little closer to the central portion side of the core wire exposed portion 3 than the facing position. It should be noted that it is not preferable to move it outside the facing position because the plasma density of the exposed core portion 3 becomes lower than the plasma density of the sheath 2. As yet another embodiment, as shown in FIG. 3, a set of a high frequency generator 17 'and a plasma delivery tube 16' is further prepared in the conventional device, and the cable 1 is connected in the same manner as in the case of FIG. The opening of the delivery pipe 16 'is located at the E portion. The positional relationship between the opening of the delivery pipe 16 'and the opening of the suction pipe 10 of the vacuum pump 11 is the same as that shown in FIG.

As a matter of course, the embodiment shown in FIG. 3 has a higher plasma density in the plasma container than the embodiment shown in FIG. 2, and the plasma processing can be performed stably, but the equipment is expensive. On the other hand, the embodiment shown in FIG. 2 has the advantage of being inexpensive in terms of equipment. Therefore, the device shown in FIG. 2 and the device shown in FIG. 3 are used properly depending on the thickness of the cable or the required quality of the gas dam cable.

As described above, by providing the opening portion of the plasma delivery pipe at the portion where the gas tightness is required most and the suction pipe opening portion at a position substantially opposite to the delivery pipe, the portion where the air tightness is required most. Therefore, the plasma density becomes high, so that the portion can be uniformly and efficiently activated in a short time. As a result, after the plasma treatment, when the resin such as epoxy and urethane is filled in the plasma treatment part,
Since the most airtight portion is uniformly and strongly adhered to the filling resin, the airtightness is improved and stabilized.

〔The invention's effect〕

As described above, according to the present invention, in the gas dam portion of the gas dam cable, the portion that requires the most airtightness, that is, the core wire exposed portion on the gas-filled side and the sheath portion that is close to the core wire exposed portion are efficiently provided. And, it can be uniformly activated by plasma. As a result, a highly reliable gas dam cable can be obtained. In addition, according to the present invention, since it is not necessary to increase the size of the plasma processing apparatus as a whole, there is no fear of increasing the cost of the apparatus.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view in which a cable is plasma-processed by a conventional plasma processing apparatus, FIG. 2 is a vertical cross-sectional view of an embodiment according to the present invention, and FIG. 3 is another embodiment of the present invention. FIG. 1 ... Cable, 3 ... Core exposed part, 4 ... Plasma processing container, 10 ... Suction pipe, 11 ... Vacuum pump, 15 ... Gas cylinder, 16 ... Delivery pipe, 17 ... High frequency generator, 18 ... Plasma generator.

Claims (1)

[Claims] 1. A cable sheath is peeled off to expose a large number of plastic-coated core wires, and the exposed core wires and the sheath portions on both sides thereof are placed in a gas plasma processing apparatus and subjected to gas plasma processing. In a method of manufacturing a gas dam cable in which a gas dam portion is formed by filling a filler over the exposed core portion and the sheath portions on both sides thereof, a gas-tight seal is provided between the exposed core portion and the sheath portions on both sides thereof. A method for manufacturing a gas dam cable, characterized in that the plasma density of the exposed core portion on the gas-filled side and the sheath portion adjacent to the exposed core portion is higher than that of other portions.