JPH0687378B2 - 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.

[Prior Art] Conventionally, a copper wire surface or a stranded wire conductor surface may be discolored during storage of copper wires and copper stranded wires, or during manufacturing process of insulated wires and storage of electric wires. In the manufacturing process, copper wire, copper stranded wire, etc. are coated with a rust preventive solution for copper.

On the other hand, vinyl chloride insulated wire (OW) as an outdoor distribution line,
Polyethylene insulated wire (OE), cross-linked polyethylene insulated wire (OC), etc. are often used, but a black copper oxide film is formed on the surface of the copper wire several 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.

This stress corrosion cracking is caused by rainwater that invades the inside of the wire from the terminal and accumulates in the voids of the wire and is concentrated into 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, it is difficult to prevent discoloration of copper for a long period of time, and there is an unfavorable problem that the insulation resistance of the insulating layer decreases. 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]

In order to achieve the above-mentioned object, the method for producing an insulated wire according to the present invention is a benzotriazole or / and a benzotriazole derivative 0.1 to 10% by weight on the surface of a center wire, a lower twisted wire and an upper twisted wire in a hard copper twisted wire, Polyester plasticizer 0.2-10
% By weight, and after applying a rust preventive solution consisting of a solvent, the amount of the polyester plasticizer added to the surface of the upper twisted wire is 0 to 0.5 wt% than the rust preventive solution before coating the insulator.
Then, a further reduced rust preventive solution is applied.

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 configuration of the present invention, as described above, the above rust-preventive solution is applied to the surface of the center wire and the lower twisted wire and the upper twisted wire in the hard copper twisted wire, and then the above-mentioned The amount of polyester plasticizer added to the surface of the stranded wire rather than the antirust solution
To specifically describe applying the anticorrosive solution which is further reduced to 0.2 to 10% by weight, in the manufacturing process of 19 hard copper concentric wires, the center wire, 6 lower twisted wires and 12 wires If an anticorrosive solution containing a large amount of polyester plasticizer is applied to each of the twisted strands of the above, a protective film of the polyester plasticizer remains thick on the surface of the 12 twisted strands. The adhesion between the insulator and the stranded copper wire is reduced, which is not preferable. Therefore, before coating the insulator on the hard copper stranded wire, a rust preventive solution containing a polyester plasticizer in an amount of 0 to 0.5% by weight is appropriately selected and applied, and is quickly dried to contact with the insulator.
The thickness of the protective film of the polyester plasticizer remaining on the final twisted strand is modified to a thin state, and further corrosion resistance is imparted to improve the adhesion between the insulator and the hard copper twisted wire.

Also, in the production of hard copper concentric stranded wire, when using the one close to the lower limit of the polyester plasticizer amount in the rust preventive solution to be applied, before coating the insulator, the polyester plasticizer amount of 0.5 wt% Apply the anticorrosion solution to the above twisted strands,
It complements the rust preventive film and provides a protective film with a polyester plasticizer to ensure excellent corrosion resistance.

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 so-called twisted wire is contained in the rust-preventive solution applied in the first step (the amount of the polyester plasticizer added is 0.2 to 10% by weight). Since there is a polyester-based plasticizer at a concentration of 1%, in the second step, that is, before coating the insulator, apply a rust preventive solution containing no polyester-based plasticizer to the surface of the upper twisted wire. However, as described above, the polyester-based plasticizer contained in the rust-preventive solution applied in the first step remains (although it is a small amount because it cannot be completely wiped off), and this is benzotriazole or / And synergistically work with benzotriazole derivatives Rust effect is induced, together because improve the adhesion between the insulator and the hard copper stranded wire. Therefore, when the amount of the polyester-based plasticizer to be added, particularly when using an anticorrosive solution of an intermediate amount from the specified upper limit, the hard copper wire in contact with the insulator before coating the insulator, that is, the upper twisted wire, Even if the amount of the plasticizer in the rust preventive solution applied to the composition is 0% by weight, the desired rust preventive effect and good adhesion can be obtained as expected.

The polyester plasticizer used in the present invention includes adipic acid polyester, sebacic acid polyester, phthalic acid polyester, adipic acid-propylene glycol polyester, adipic acid-1,3 butylene glycol 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. As such a solvent, methyl alcohol is used. Alcohol solvents such as ethyl alcohol and isopropyl alcohol and trichloroethane are preferable, 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 salt, benzotriazole diisopropylamine salt, and methylbenzotriazolecyclohexylamine salt. Can also be used.

[Action]

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 to the surface of the center line and the lower twisted wire and the upper twisted wire in, in the presence of alcohol, a rust preventive film by chelate bond with a rust preventive component is well formed on the copper surface, and if the alcohol volatilizes, The contained polyester plasticizer is formed as a protective film on the rust preventive film, the double rust preventive effect is enhanced, and the corrosion resistance is improved.

Further, the rust preventive solution is applied to the surfaces of the center wire, the lower twisted wire, and the upper twisted wire in the hard copper twisted wire, and then the surface of the upper twisted wire is coated with the rust preventive solution before covering the insulator. A polyester system in which a rust preventive solution in which the amount of the polyester plasticizer added is further reduced to 0 to 0.5% by weight is appropriately selected and applied on the upper twisted wire in contact with the insulator and quickly dried to remain on the upper twisted wire. The film thickness of the polyester plasticizer remaining in the upper twisted wire in contact with the insulator is adjusted so that the plasticizer film can be adjusted in stickiness and uniformized, and the rust preventive film on the upper twisted wire is complemented at the same time. Even if there is some, it can 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 the desired state as desired, but 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 regard, in the present invention, as described above, the rust-prevention applied first to the center wire, the lower twisted wire and the upper twisted wire in the hard copper twisted wire on the surface of the upper twisted wire before coating the insulator. By applying a means of applying an anticorrosive solution in which the amount of polyester plasticizer added is 0 to 0.5% by weight less than that of the solution, in other words, the first application to enhance the antirust effect is polyester. The problem of slippage that occurs between the insulator and the upper twisted wire in contact with the rust preventive solution containing a high concentration of the plasticizer is the polyester in the rust preventive solution applied in the second rust preventive treatment. A thin state of the protective film of the polyester plasticizer remaining on the twisted wire in contact with this insulator by thinning the plasticizer as much as possible and applying it again on the twisted wire in contact with this insulator. To improve corrosion resistance Since it improves the adhesion between the edge body and the upper twisted wire, the conflicting requirements that the improvement of the rust prevention effect impairs the adhesion with the upper twisted wire in contact with the insulator were solved satisfactorily. Was able to achieve the purpose of

〔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 stripped was immersed in an aqueous sodium sulfide solution having a concentration of 100 ppm for 30 seconds at room temperature, and then taken out, and the discolored state of the surface of the conductor wire was visually observed to judge 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 tests, but Comparative Examples 1 and 2 correspond to Examples 1 and 3, and the twisted copper element in contact with the insulator is used. Since the anticorrosive solution is not applied on the wires before insulation,
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 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 amount of the polyester plasticizer added in the anticorrosive solution applied on the copper wire is not appropriate, the protective film on the anticorrosive film lacks and the corrosion resistance test is not preferable.

〔The invention's effect〕

As described above, according to the manufacturing method of the present invention,
During the manufacturing process of insulated wires or power cables, it is possible to obtain an insulated wire that has good adhesion to the twisted copper wire in contact with the insulator and has an excellent corrosion-resistant coating and protective coating on the stranded conductor. Also, it can sufficiently prevent the problem of discoloration of the stranded wire conductor during storage of the wire, and even after corrosive rainwater enters from the end of the wire as an insulated 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 a benzotriazole derivative in an amount of 0.1 to 10% by weight on the surface of a center wire, a lower twisted wire and an upper twisted wire of a hard copper twisted wire, and a polyester plasticizer.
After applying a rust preventive solution containing 0.2 to 10% by weight and the remainder being a solvent, and before coating the insulator, the amount of the polyester plasticizer added to the surface of the upper twisted wire is 0 to 10% higher than that of the rust preventive solution. 0.
A method for producing an insulated wire, which comprises applying an anticorrosive solution further reduced to 5% by weight.