JPH0730470B2 - Insulated wire and manufacturing method thereof - 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, during storage of copper wires and copper stranded wires, or during the manufacturing process and storage of insulated electric wires, the surface of the copper wires and the surface of the stranded conductor may be discolored. Anticorrosion solution for copper is applied to copper stranded wire.

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. This 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 has entered 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 coating on a copper stranded wire (for example, JP-A-61-277
(See Japanese Patent Publication No. 120). Have 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]

The structure of the present invention is such that benzotriazole
0.1 to 10% by weight, phosphoric acid-based plasticizer 2 to 70% by weight, the balance is applied after applying a rust preventive solution consisting of a solvent, 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 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 projected, 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 phosphoric acid plasticizer used is 2 to 70% by weight. When the amount is 70% by weight or more, stickiness remains on the stranded conductor after application and the pull-out test is not preferable, and benzotriazole cannot be sufficiently dissolved. . On the other hand, if it is 1% by weight or less, it is difficult to obtain a sufficient rust-preventing 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 phosphoric acid-based plasticizers used are trimethyl phosphate, tributyl phosphate, tri- (2-ethylhexyl) phosphate, 2-ethylhexyl diphenyl phosphate, tributoxyethyl phosphate, triphenyl phosphate, cresyl diphenyl phosphate. , Isodecyl diphenyl phosphate, tricresyl phosphate, tritolyl phosphate, trixylenyl phosphate, alkyl
One or more of these groups can be used, such as allyl phosphate.

The solvent to be used is used for facilitating the dissolution and mixing of benzotriazole and the phosphoric acid-based plasticizer and for adjusting the stickiness of the phosphoric acid-based plasticizer. Examples of such a solvent include methanol and isopropyl alcohol. Alcohol-based solvents are preferred, but are not particularly limited.

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 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, apply the anticorrosive solution of each composition shown in Table 1 to the outer periphery, and further extrude and coat polyethylene insulator on the outer periphery. 60 mm ² outdoor polyethylene insulated wire was manufactured.
Each of the obtained insulated wires was subjected to the following corrosion resistance test (Note 1, Note 2, Note 3) and conductor pull-out test (Note 4). The results are shown in Table 1 as a blending example (blending is% by weight)
Shown in line with the bottom row.

(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.

(Note 1) (Note 2) was evaluated as follows: ○ indicates no discoloration, Δ indicates slight discoloration, and × 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) When a 3m long sample is cut from an insulated wire with a gold saw, the insulator at 1m on one end is peeled off by 10cm, the other end is fixed, and a load of 1ton (pulling load) is applied to the insulator on one end. Then, the condition of pulling out the insulator was observed to judge whether the adhesion between the conductor and the insulator was good or bad.

Further, in order to judge higher adhesion, the insulator was peeled off at 30 cm from one end, and the same pulling load as described 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 compounding amount of cresyl diphenyl phosphate is large, the adhesion between the conductor and the insulator is lowered, and the conductor pull-out test is not preferable. Comparative Example 3
Has a small amount of cresyl diphenyl phosphate, so its role as a protective film on the corrosion resistant film with copper is insufficient. When Comparative Examples 4, 5 and 6 and Examples 3, 4 and 5 are compared and considered, use of silicone oil, liquid paraffin, electric insulating oil and the like of Comparative Example, and use of phosphoric acid type plasticizer of Example The results show that there is a large difference in the results in the corrosion resistance tests (Note 1, Note 2, Note 3). The reason for this is
In the examples, it is presumed that a corrosion resistant film with copper is formed well. Particularly, in Comparative Example 4 in which silicone oil is used, the adhesion between the conductor and the insulator is significantly reduced. Conventional example
With 1,2,3, a large amount of silicone oil, liquid paraffin, and polybutene are used to form a protective film on the copper wire, but this reduces the adhesion between the conductor and the insulator, making the conductor pull-out test unfavorable. Is suspected to cause problems when used as. Considering the examples and the conventional examples in comparison with each other in the corrosion resistance test (Note 2), since the corrosion resistant film with copper is well formed in the examples, the corrosion resistant film formed even when immersed in the sodium sulfide aqueous solution is Shows excellent resistance to the severe corrosive environment,
In the conventional example, the benzotriazole derivative is a silicone oil,
Since a non-aqueous rust preventive oil dispersed and included in liquid paraffin or polybutene is used, it is extremely difficult to form an anticorrosive film with copper. It is presumed that when the oil is removed with a solvent and immersed in an aqueous solution of sodium sulfide, the resistance to the corrosive environment is lacking, and therefore the color is clearly changed to black.

In addition, in the adhesion test in which the insulator was peeled off at 30 cm from one end, the amount of the plasticizer was 40 wt.
It has been found that when it exceeds%, it drops sharply.

Further, 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 adsorbed after the solvent was evaporated) was measured and found to be 3.0 × 10 ^-4 g / It has been found that when it is less than cm ^2, it can withstand pulling out of 30 cm −1 ton and cannot withstand pulling beyond this.

〔The invention's effect〕

As described above, according to the manufacturing method of the present invention,
When a rust preventive solution consisting of benzotriazole or / and a benzotriazole derivative 0.1 to 10% by weight, a phosphoric acid plasticizer 2 to 70% by weight, and the remainder being a solvent is applied to the surface of the hard copper twisted wire, in the presence of the solvent, A rust preventive film is formed favorably on the copper surface by a chelate bond with a rust preventive component, and when the solvent is volatilized, a phosphoric acid-based plasticizer contained is formed as a protective film on the rust preventive film. The rust prevention effect is enhanced,
Corrosion resistance is improved. Moreover, by adjusting the addition amount of the phosphoric acid-based plasticizer to 2 to 70% by weight, the viscosity of the phosphoric acid-based plasticizer film remaining on the copper wire is adjusted and made uniform, and Since the rustproof film on the wire is complemented at the same time, it is suitable for severe corrosion resistance and conductor pull-out tests, and can prevent stress corrosion breakage. Therefore, it is possible to obtain an insulated electric wire that has good adhesion to the twisted copper element wire in contact with the insulator and has an excellent corrosion-resistant coating and protective coating on the twisted-wire conductor. It is possible to sufficiently prevent the problem of discoloration of the stranded wire conductor during storage in and inside the wire, and even after corrosive rainwater has entered from the end of the wire after it was installed as an insulated wire for outdoor use,
The effect is great because there is no fear of causing stress corrosion cracking.

Furthermore, in the insulated wire of the present invention, the adhesion between the insulated wire and the hard copper stranded wire is remarkably improved, and the pull-out strength is insufficient to prevent unexpected entry of rainwater into the hard copper stranded wire. Contributes to the improvement of corrosion resistance.

 ─────────────────────────────────────────────────── ─── 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-53-142942 (JP, A) ) JP-A-57-123980 (JP, A) JP-A-1-195292 (JP, A) JP-A-1-281608 (JP, A) JP-A-1-219183 (JP, A) Actual development 61- 35317 (JP, U)

Claims (2)

[Claims] 1. Benzotriazole 0.1 is formed on the surface of a hard copper stranded wire.
~ 10% by weight, phosphoric acid plasticizer 2 ~ 70% by weight, the rest is applied a rust preventive solution consisting of a solvent, the insulating coating layer is formed on the outer periphery of the hard copper stranded wire Manufacturing method. 2. The ratio of the benzotriazole or its derivative to the phosphoric acid plasticizer on the surface of the twisted wire in contact with the insulator is 0.
An insulated wire, characterized in that the admixture in the range of 1: 2 to 10:40 is applied at an actual amount of 3.0 × 10 ^-4 g / cm ² or less.