JPH06101260B2 - Insulated wire manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing an insulated wire and a power cable in which discoloration of a copper stranded wire surface is prevented for a long period of time by using a benzotriazole anticorrosive solution.

[Conventional technology]

Conventionally, the surface of a copper wire or the surface of a stranded conductor may be discolored during storage of copper wires and stranded copper wires, or during the manufacturing process of insulated wires and during storage of electric wires. , Anti-corrosion solution for copper is applied to stranded copper wire.

On the other hand, vinyl chloride insulated wire (OW) as an outdoor distribution line,
Polyethylene insulated wire (OE), Chinese polyethylene insulated wire (OC), etc. are widely used, but a black copper oxide film is formed on the copper wire surface within a few years after the overhead wire, and rarely hard copper stranded wire is knife-cut. It may cause a so-called stress corrosion cracking, which is an important problem in terms of power security.

In this stress corrosion cracking, rainwater that has entered the inside of the wire from the end accumulates in the voids of the wire and is concentrated to form corrosive water, forming a thick black copper oxide film on the surface of the copper wire and cracking the film. Between the corrosion factor that selectively dissolves the underlying copper exposed at the part and the stress factors such as the stress generated during the overhead wire against the bending stress generated during the processing of the hard copper stranded wire and the bending stress generated during the winding of the wire drum. It is supposed to occur due to interaction.

Against stress corrosion cracking that occurs in such a long-term corrosive environment, even if a solution of benzotriazole dissolved in a volatile solvent such as alcohol alone is applied to a hard copper strand, a sufficient corrosion resistant film is not formed Therefore, a long-term corrosion resistance effect cannot be expected and there is a problem that stress corrosion cracking occurs.

Therefore, as a solution, a method of using an insulating layer containing a rust preventive component for copper, a method of filling a watertight compound in a hard copper twisted wire, a solution of a benzotriazole derivative dissolved in liquid paraffin, polybutene, silicone oil, etc. A method of applying on a copper stranded wire has been proposed.

However, with respect to (1), it is difficult to elute the rust preventive agent from the insulating layer, and it is difficult to prevent discoloration of copper for a long period of time. With respect to the above, there is a problem in that the manufacturing cost is high, the work of removing the watertight compound is troublesome, and when the removal is not sufficient, the energization characteristics of the connection portion deteriorate. For, the use of it reduces the adhesion between the insulator and the hard copper stranded wire,
There is a problem that the pulling strength is insufficient.

[Problems to be solved by the invention]

The present invention has been made in view of the above problems, by applying a rust-preventive solution to the hard copper stranded wire, to form a strong corrosion-resistant coating on the surface of the copper wire or hard copper stranded wire, hard copper Even if corrosive rainwater enters the stranded wire, it maintains the copper color for a long time,
Moreover, it is an object of the present invention to provide an insulated electric wire and a method for manufacturing an electric power cable in which the adhesion between the insulator and the hard copper stranded wire is good.

[Means for solving problems]

Therefore, in order to achieve the above-mentioned object, the method for producing an insulated wire of the present invention comprises a benzotriazole or / and a benzotriazole derivative in an amount of 0.1 to 10% by weight of polyester on the surface of a center wire or / and a lower twisted wire in a hard copper twisted wire, a polyester. Plasticizer
0.2-10% by weight, the rest was applied a rust preventive solution consisting of a solvent, then the surface of the twisted wire was applied a rust preventive solution containing a relatively smaller amount of polyester plasticizer than the rust preventive solution After that, before coating the insulator, a rust preventive solution in which the amount of the polyester plasticizer added is further reduced to 0 to 0.3% by weight from the rust preventive solution is applied to the surface of the upper twisted wire. .

Hereinafter, the structure of the present invention will be described in more detail.

In the anticorrosive solution used in the present invention, the addition amount of benzotriazole is set to 0.1 to 10% by weight, because the corrosion resistant film is not formed even more than 10% by weight,
The rust preventive effect reaches saturation and an excessive amount is precipitated, which is not preferable. On the other hand, if the addition amount is 0.1% by weight or less, a sufficient corrosion resistant film is not formed, and thus the rust preventive effect cannot be obtained. The preferable addition amount of benzotriazole is 1 to 5% by weight. The amount of the polyester plasticizer used is 0.2 to 10% by weight. When the amount is 10% by weight or more, stickiness remains on the stranded wire conductor after coating and the conductor pull-out test is not preferable. vice versa,
If it is less than 0.2% by weight, it is difficult to obtain a sufficient rust-preventing effect because it lacks a protective effect on the formed corrosion-resistant film.

Next, in the constitution of the present invention, as described above, the surface of the center wire or / and the lower twisted wire in the hard copper twisted wire is coated with the rust preventive solution, and then the surface of the upper twisted wire is coated with polyester from the rust preventive solution. After applying a rust-preventive solution containing a relatively small amount of the plasticizer, before the final coating of the insulator, a polyester-based plasticizer is added to the surface of the upper twisted wire rather than the rust-preventive solution. Specifically, the application of the rust preventive solution whose amount is further reduced to 0 to 0.3% by weight is specifically explained. In the process of manufacturing 19 hard copper concentric stranded wires, the central strand and 6 lower strands The wires are coated with a rust preventive solution containing a large amount of polyester plasticizer, and the 12 twists are coated with a rust preventive solution containing less polyester plasticizer than the former, and an insulator is applied on the coated hard copper stranded wire. When coating, the amount of polyester plasticizer added was 0-0.3% by weight Select a suitable rust solution, apply it, and dry it quickly, and cover the insulator by reducing the protective coating thickness of the polyester plasticizer remaining on the 12 twisted strands that come into contact with the insulator. This is because the adhesion with the stranded wire can be improved, and the insulated wire has excellent corrosion resistance and is suitable for crossing.

In this case, the addition amount of the polyester-based plasticizer shown in the present invention from the specific upper limit to the intermediate amount of the anticorrosive solution, each applied to the central wire and the lower twisted wire and the upper twisted wire, the insulation Since the protective coating of the polyester plasticizer remains thick on the surface of the 12 twisted strands that come into contact with the body, applying an insulator undesirably reduces the adhesion between the insulator and the hard copper stranded wire. Therefore, by applying a rust preventive solution without adding a polyester plasticizer, the thickness of the protective film of the polyester plasticizer remaining on the 12 twisted strands is modified to a thin state,
Furthermore, corrosion resistance is imparted to improve the adhesion between the insulator and the hard copper stranded wire.

Next, in the case of 7 pieces of hard copper concentric stranded wire, since it is composed of a central element wire and 6 top-twisted element wires, the polyester plasticizer from the center of the stranded conductor toward the direction of contact with the insulator It is also possible to successively reduce the amount of addition.

As described above, it is sufficient that the amount of the polyester plasticizer added to the rust preventive solution applied to the surface of the twisted wire (twisted strand) before coating the insulator is 0% by weight. As described in detail above, the surface of the upper twisted wire has the rust-preventive solution applied in the first step (the addition amount of the polyester plasticizer is 0.
2 to 10% by weight), since there is a certain amount of polyester plasticizer contained in the second step,
That is, even if a rust preventive solution containing no polyester-based plasticizer is applied to the surface of the upper twisted wire before coating the insulator, as described above, the rust preventive solution contained in the rust preventive solution applied in the first step is included. Remaining polyester plasticizer (although not completely wiped off, but a trace amount) remains, and this synergistically works with benzotriazole or / and benzotriazole derivative to induce sufficient rust prevention effect, This is also because it improves the adhesion between the insulator and the hard copper stranded wire. Therefore,
When using a rust-preventive solution with an amount of polyester plasticizer from the specified upper limit to an intermediate amount, apply it to the hard copper wire in contact with the insulator before coating the insulator, that is, the upper twisted wire. Even if the amount of plasticizer in the rust preventive solution is 0% by weight,
A desired rust preventive effect and good adhesion can be obtained as expected.

The polyester-based plasticizer used in the present invention includes adipic acid-based polyester, sepacic acid-based polyester, phthalic acid-based polyester, adipic acid-propylene glycol-based polyester, adipic acid-1,3 butylene glycol-based polyester, and the like. One or more of can be used.

The solvent used is used for facilitating the dissolution and mixing of the benzotriazole or / and the benzotriazole derivative and the polyester plasticizer, and for adjusting the stickiness of the polyester plasticizer.
Alcohol solvents such as methyl alcohol, ethyl alcohol and isopropyl alcohol and trichloroethane are preferred, but not limited thereto.

In the present invention, in addition to benzotriazole, benzotriazole derivatives such as benzotriazole monoethanolamine salt, benzotriazole diethylamine salt, benzotriazole cyclohexylamine salt, benzotriazolemorpholine acid, benzotriazole diisopropylamine salt, and methylbenzotriazolecyclohexylamine salt. Can also be used.

[Work]

The cause of disconnection of outdoor insulated wires due to stress corrosion cracking is
After the insulated electric wire is suspended, corrosive rainwater penetrates into the twisted voids of the hard copper stranded wire inside the electric wire from a slight gap such as a detention portion, a terminal portion or a connection portion, and the corrosion accumulates for a long period of time. The first factor is the factor. Therefore, the requirements to be satisfied as an outdoor insulated wire are excellent corrosion resistance and a strict conductor pull-out test corresponding to an overhead wire, that is, good adhesion to a copper wire in contact with an insulator.

A rust preventive solution used in the present invention, that is, a benzotriazole or / and a benzotriazole derivative 0.1 to 10% by weight, a polyester plasticizer 0.2 to 10% by weight, and a balance of an rust preventive solution which is a solvent such as alcohol is a hard copper twisted wire. When applied on the surface of the center line or / and the lower twisted wire in, the rust preventive film by the chelate bond with the rust preventive component is satisfactorily formed on the copper surface in the presence of alcohol, and if the alcohol volatilizes, the polyester contained The system plasticizer is formed as a protective film on the rust preventive film to enhance the double rust preventive effect and improve the corrosion resistance.

In addition, the center line or / and the surface of the lower twisted wire in the hard copper twisted wire is coated with the rust preventive solution, and then the amount of the polyester plasticizer is relatively adjusted to the surface of the upper twisted wire than the rust preventive solution. After applying the reduced rust preventive solution and before finally covering the insulator, the amount of the polyester plasticizer added to the surface of the twisted wire is further reduced to 0 to 0.3% by weight as compared with the rust preventive solution. Apply the rust preventive solution and dry it quickly to adjust the stickiness and homogenize the polyester plasticizer film remaining on the upper twisted wire, and at the same time, complement the rust preventive film on the upper twisted wire. As a result, it is possible to meet severe corrosion resistance and conductor pull-out tests and prevent stress corrosion breakage.

In other words, if the amount of polyester plasticizer added to the rust preventive solution is large (however, it is not preferable to exceed 10% by weight), the rust preventive effect and corrosion resistance can be achieved in a desired state as desired, but the coating After that, the film of the polyester-based plasticizer remaining on the upper twisted wire in contact with the insulator inevitably becomes thicker, so when the wire is made into an insulated wire, the adhesion between the insulator and the upper twisted wire decreases, and the Are pulled out, which causes an undesirable problem.

In this respect, according to the present invention, as described above, before coating the insulator, the surface of the upper twisted wire is treated with a rust preventive solution which is first applied to the center line or / and the lower twisted wire of the hard copper twisted wire. Also, after applying a rust preventive solution containing a relatively small amount of the polyester plasticizer, before finally covering the insulator, the surface of the upper twisted wire is a polyester plasticizer than the rust preventive solution. By applying a means of applying an anticorrosive solution in which the addition amount of is further reduced to 0 to 0.3% by weight, in other words, the first application that enhances the anticorrosion effect has a high concentration of polyester plasticizer. The problem of slippage that occurs between the insulator and the upper stranded wire that contacts the rust preventive solution is that the polyester plasticizer in the rust preventive solution applied in the second rust preventive treatment is as much as possible. On the upper stranded wire that is thinly contacted with this insulator again By applying a cloth, the thickness of the protective film of polyester plasticizer remaining on the upper twisted wire in contact with this insulator is modified to a thin state, and corrosion resistance is added to further improve the adhesion between the insulator and the upper twisted wire. Therefore, we were able to successfully solve the conflicting requirements that the improvement of rust prevention effect impairs the adhesion with the upper stranded wire in contact with the insulator, and successfully achieved the intended purpose. ..

〔Example〕

Hereinafter, an example according to the present invention and a comparative example will be described in comparison.

When twisting 19 hard copper wires with an outer diameter of 2.0 mmφ into concentric strands and covering the outer circumference with polyethylene insulation, pre-twist the center wire and 6 lower twists, 12 upper twisted copper wires and insulation Before coating, the surface of the copper wire in contact with the insulator is coated with a rust preventive solution having the respective composition shown in Table 1. For example, the application of the center strand, 6 lower twisted strands and 12 upper twisted strands is carried out by quantitatively feeding the rust preventive solution with a micro pump and passing it through a rust preventive tank equipped with an air wiper. To coat the surface of the copper wire in contact with the insulator, wind the felt with a weight around the stranded wire, and quantitatively send the rust preventive solution to the upper end with a micropump, pass through a hot air dryer, and dry quickly. . Subsequently, the outer circumference was extrusion-coated with a polyethylene insulator to produce a 60 mm ² outdoor polyethylene insulated wire. For each of the obtained insulated wires, the corrosion resistance test (Note 1, Note 2,
Note 3) and induction pull-out test (Note 4) were conducted. The results are shown in the lower part of Table 1.

(Note 1) Cut a 10 cm long sample from the insulated wire with a gold saw,
The conductor wire from which the insulator had been peeled off was immersed in a 100 ppm concentration sodium sulfide aqueous solution at room temperature for 30 seconds, then taken out, and the discolored state of the surface of the conductor wire was visually observed to determine whether the corrosion resistance was good or bad.

(Note 2) Cut a 10 cm long sample from the insulated wire with a gold saw,
After peeling off the insulator, taking out the hard copper stranded wire and washing off the rust preventive solution adhering to the surface of the conductor wire with a solvent, the concentration is 100 ppm
After being immersed in the sodium sulfide aqueous solution for 30 seconds at room temperature, it was taken out, and the discolored state of the surface of the conductor wire was visually observed to judge the corrosion resistance.

The judgment criteria of (Note 1) and (Note 2) were evaluated as follows: ○ indicates no discoloration, Δ indicates slight discoloration, and X indicates clear discoloration.

(Note 3) Cut a 30 cm long sample from the insulated wire with a gold saw,
Dip it 1/2 in 100ppm aqueous ammonia solution,
A heat cycle of 8 hours at ℃ and 16 hours at room temperature is continued for 1 week and then immersed in a corrosive environment where it is replaced with fresh ammonia solution for 8 weeks, then the sample is taken out, the insulator is peeled off, and the oxidation generated on the conductor The average film thickness of copper was determined, and the value was used to judge the corrosion resistance.

Judgment criteria are as follows: ○ indicates a film thickness of less than 0.2 μm, Δ indicates a film thickness in the range of 0.2 to 0.3 μm, × indicates a film thickness of 0.
It was evaluated as exceeding 3 μm.

(Note 4) A 3 m long sample was cut from the insulated wire with a gold saw, the insulator at one end 0.3 m was peeled off by 10 cm, the other end was fixed, and a load of 1 ton (pulling load) was applied to the insulator at one end. At this time, the condition of pulling out the insulator was observed to judge whether the adhesion between the conductor and the insulator was good or bad.

The criteria for evaluation were evaluated as those in which ○ was difficult to pull out, those in which Δ was slightly pulled out, and those in which X was largely pulled out.

As can be seen from the results, Examples 1 to 5 show good results in all the tests, but Comparative Example 1 does not apply the rust preventive solution on the twisted copper wire as an insulator before the insulation. Therefore, although it has corrosion resistance, the adhesion between the conductor and the insulator decreases, and the conductor pull-out test is not preferable. In Comparative Example 2, the polyester-based plasticizer film remaining on the twisted copper wire was thick, but the amount of the polyester-based plasticizer added in the rust preventive solution applied before the insulation was not appropriate, so that the conductor and the insulator were Adhesion is reduced and the conductor pull-out test becomes unfavorable. In Comparative Example 3, since the amount of benzotriazole added was small, a sufficient corrosion resistant film was not formed on the copper surface, which is not preferable.

In Comparative Example 4, since the polyester plasticizer film remaining on the twisted copper wire is extremely thick, even if a rust preventive solution containing no polyester plasticizer applied before insulation is applied, the twisted copper wire is applied on the twisted copper wire. The adjustment and homogenization of the viscosity of the polyester plasticizer film that remains appropriately become insufficient, and the conductor extraction test becomes unfavorable. In Comparative Example 5, the corrosion resistance test is not preferable because the amount of the polyester plasticizer added in the rust preventive solution applied on the center wire, the lower twisted and the upper twisted copper strands is not appropriate.

〔The invention's effect〕

As described above, according to the manufacturing method of the present invention,
During the process of manufacturing insulated wires or power cables, it is possible to obtain an insulated wire that has good adhesion to the twisted copper wire that contacts the insulator and that has an excellent corrosion-resistant film and protective film on the stranded wire conductor. Also, the problem of discoloration of the stranded conductor during storage of the electric wire can be sufficiently prevented, and even if corrosive rainwater enters from the terminal part etc. after crosslinking as an insulated electric wire for outdoor use, stress corrosion cracking will occur. Since there is no fear, the effect is great.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Chikashi Takeya 2-3-1 Iwata-cho, Higashi-Osaka City, Osaka Prefecture Tatsuta Electric Wire Co., Ltd. (56) Reference JP-A-57-57416 (JP, A) ) JP-A-62-200604 (JP, A)

Claims (1)

[Claims] 1. A benzotriazole or / and benzotriazole derivative in an amount of 0.1 to 10% by weight on the surface of a center wire or / and a lower twisted wire of a hard copper twisted wire, a polyester plasticizer.
0.2-10% by weight, the rest was applied a rust preventive solution consisting of a solvent, then the surface of the twisted wire was applied a rust preventive solution containing a relatively smaller amount of polyester plasticizer than the rust preventive solution After that, before coating the insulator, the surface of the upper twisted wire is coated with a rust preventive solution in which the amount of the polyester plasticizer added is further reduced to 0 to 0.3% by weight compared to the rust preventive solution. And a method of manufacturing an insulated wire.