JPH0650602B2 - Insulated wire and its 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 (O
W), polyethylene insulated electric wire (OE), cross-linked polyethylene insulated electric wire (OC), etc. are often used.
In a few years, a black copper oxide film is formed on the surface of the copper wire, and sometimes the hard copper stranded wire is abnormally cut into a knife cut, so-called stress corrosion cracking may occur, which is an important problem for power security. Has become.

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, there is a problem that a long-term corrosion resistance effect cannot be expected.

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 that the manufacturing cost is high, the work of removing the watertight copper band is troublesome, and if the removal is not sufficient, the current-carrying characteristics of the connection part deteriorate. However, there is a problem in that the use thereof lowers the adhesion between the insulator and the hard copper stranded wire, resulting in insufficient drawing strength.

[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]

The structure of the present invention is such that benzotriazole
0.1 to 10% by weight, a phthalic acid-based plasticizer 2 to 70% by weight, and a rust preventive solution consisting of the balance of the solvent is applied, and then an insulating coating layer is formed on the outer periphery of the hard copper stranded wire. Is.

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 0.1-10% by weight is 10% by weight.
Even if added in the above amount, the corrosion resistant film is not formed any more, the rust-preventing effect reaches saturation, and an excessive amount is deposited, 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 phthalic acid plasticizer used is 2 to 70% by weight. When the amount is 70% by weight or more, stickiness remains on the stranded wire conductor after coating and the pull-out test is not preferable, and benzotriazole cannot be sufficiently dissolved. . Conversely, 1% by weight
In the following, it is difficult to obtain a sufficient rust preventive effect because it lacks a protective effect on the formed corrosion resistant film. The solvent used is preferably an alcohol solvent such as methanol.

The phthalic acid-based plasticizer used is dimethyl phthalate,
Diethyl phthalate, dibutyl phthalate, dioctyl phthalate, di-n-octyl phthalate, higher alcohol phthalate, diisooctyl phthalate, diisobutyl phthalate, diheptyl phthalate, diphenyl phthalate, diisodecyl phthalate, ditridecyl phthalate, dinonyl phthalate, dinormal alkyl phthalate. , Benzyl phthalate, dimethoxyethyl phthalate, dimethyl cyclohexyl phthalate, alkylbenzyl phthalate, methyl phthalyl glycolate, etc., and one or more of these groups can be used.

The solvent used is used for facilitating the dissolution and mixing of the benzotriazole and the phthalic acid-based plasticizer, and for adjusting the stickiness of the phthalic acid-based plasticizer. Examples of the solvent include alcohols such as methanol and isopropyl alcohol. A system solvent is preferable, but not particularly limited.

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

〔Example〕

Hereinafter, examples according to the present invention will be described in comparison with comparative examples and conventional examples.

After twisting 19 pieces of hard copper wires with an outer diameter of 2.0 mmφ into concentric strands, the rust preventive solution of each composition shown in Table 1 is applied to the outer circumference, and the outer circumference is extrusion-coated with a polyethylene insulator. A 60 mm ² outdoor polyethylene insulated wire was manufactured. Corrosion resistance test (Note 1, Note 2, Note 3) and conductor pull-out test (Note 4) for each of the obtained insulated wires
Was done. The results are shown in Table 1 together with the lower row.

(Note 1) A 10 cm long sample from an insulated wire was cut with a gold saw, and the conductor wire from which the insulation had been peeled was immersed in a 100 ppm sodium sulfide aqueous solution for 30 seconds at room temperature and then taken out to discolor the conductor wire surface. The state was visually observed and the quality of corrosion resistance was judged.

(Note 2) A 10 cm long sample is cut from the insulated wire with a gold saw, the insulator is peeled off, the hard copper stranded wire is taken out, and the rust preventive solution adhering to the surface of the conductor wire is washed off with a solvent, Concentration 1
After immersing in 00ppm sodium sulfide aqueous solution for 30 seconds at room temperature, take it out and visually check the discolored state of the conductor wire surface.
The quality of corrosion resistance was judged.

(Note 1) (Note 2) was evaluated as follows: ○ indicates no discoloration, Δ indicates slight discoloration, and × indicates clear discoloration.

(Note 3) A 30 cm long sample from an insulated wire is cut with a gold saw, immersed in 1/2 aqueous ammonia solution with a concentration of 100 ppm for 1 hour, followed by a heat cycle of 8 hours at 60 ° C and 16 hours at room temperature. Was immersed in a corrosive environment where it was replaced with a new ammonia solution for 8 weeks, then took out the sample, peeled off the insulator, calculated the average film thickness of the copper oxide formed on the conductor, and determined the corrosion resistance from that value. did.

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) Cut a 3m long sample from the insulated wire with a gold saw,
Peel off the insulator by 10 cm at 1 m from one end, fix the other end, and observe the pull-out condition of the insulator when a load of 1 ton (pulling load) is applied to the insulator at one end, The adhesion was judged to be good or bad.

In addition, 30 cm from one end to judge even higher adhesion.
At that point, the 10 cm insulator was peeled off, and a pulling load similar to the above was applied to observe the sliding of the insulator.

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 6 show good results in all tests, but Comparative Example 1 does not form a sufficient corrosion resistant film with copper because the amount of benzotriazole added is small. In Comparative Example 2, since the content of dioctyl phthalate is large, the adhesion between the conductor and the insulator is reduced, and the conductor pull-out test is not preferable. In Comparative Example 3, since the amount of dioctyl phthalate is small, the role as a protective film on the corrosion resistant film with copper is insufficient. Considering the comparison between Comparative Examples 4, 5 and 6 and Examples 4, 5 and 6, the use of silicone oil, liquid paraffin, electrical insulating oil, etc. in Comparative Example,
It can be seen that there is a large difference in the results in the corrosion resistance test (Note 1, Note 2, Note 3) from the use of the phthalic acid-based plasticizer in the examples. The reason for this is presumed to be that a corrosion resistant film with copper is favorably formed in the examples. Particularly, in Comparative Example 4 in which silicone oil is used, the adhesion between the conductor and the insulator is significantly reduced. In Conventional Examples 1, 2, and 3, a large amount of silicone oil, liquid paraffin, and polybutene is used to form a protective film on the copper wire, but this reduces the adhesion between the conductor and the insulator, and the conductor pull-out test is unfavorable. It is speculated that problems may occur when used as an insulated wire. Considering the examples and the conventional examples in comparison with each other in a corrosion resistance test (Note 2), since a corrosion resistant film with copper is well formed in the example, the corrosion resistant film formed even when immersed in an aqueous solution of sodium sulfide, It has excellent resistance to severe corrosive environment, but in the conventional example, a non-aqueous rust preventive oil in which a benzotriazole derivative is dispersed and included in silicone oil, liquid paraffin, polybutene, etc. is used. Since it is extremely difficult to form an anticorrosive film with, the anticorrosion oil applied and adhered to the copper wire surface is removed with a solvent, and when immersed in an aqueous sodium sulfide solution, it lacks resistance to the corrosive environment, It is presumed that it will turn black clearly.

In addition, in the adhesion test in which the insulator was peeled off at 30 cm from one end, it was found that the amount decreased sharply when the amount of the plasticizer exceeded 40 wt%, which is not shown in detail in Table 1.

After the above test, the amount of the mixture of benzotriazole and the plasticizer adhering to the surface of the 12 twisted wires in contact with the insulator (the amount actually adhering after the solvent was evaporated) was measured and found to be 3.0 × 10 ^-4 g / cm 3. It was found that if it was less than ² , it could withstand pulling out of 30 cm-1 ton, but if it exceeded this, it could not withstand.

〔The invention's effect〕

As described above, according to the manufacturing method of the present invention,
Since an insulated wire with an excellent corrosion-resistant coating and protective coating on a stranded wire conductor can be obtained, it is necessary to sufficiently prevent the problem of discoloration of the stranded wire conductor during the manufacturing process of insulated wires or power cables and during storage of wires. Moreover, even if corrosive rainwater enters from the end of the insulated wire for outdoor use after the wire is suspended, there is no fear of causing stress corrosion cracking, so that the effect is great.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Chikashi Taketani 2-3-1 Iwata-cho, Higashi-Osaka City, Osaka Prefecture Tatsuta Electric Wire Co., Ltd. (56) Reference JP-A-1-195292 (JP, A) ) JP-A-61-277121 (JP, A) JP-A-62-200609 (JP, A)

Claims (2)

[Claims] 1. Benzotriazole 0.1 is formed on the surface of a hard copper stranded wire.
-10 wt%, phthalic acid-based plasticizer 2 to 70 wt%, the rest is applied a rust preventive solution consisting of a solvent, and then an insulating coating layer is formed on the outer periphery of the hard copper stranded wire. Manufacturing method. 2. A mixture having a ratio of benzotriazole or its derivative to a phthalic acid plasticizer in the range of 0.1: 2 to 10:40 on the surface of the twisted wire in contact with the insulator is 3.0 × 10.
^-4 Insulated electric wire, characterized in that it is applied in an actual amount of not more than ⁴ g / cm ² .