JPH07105170B2 - 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) and cross-linked polyethylene insulated wire (OC) are often used, but a black copper oxide film is formed on the copper wire surface several years after cross-linking, 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 invading the inside of the wire from the terminal, which accumulates in the void 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 (as an example, JP-A-61-27
(See Japanese Patent No. 7120). Have 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 work of removing the watertight coup 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, after coating the surface of the hard copper stranded wire benzotriazole or / and benzotriazole derivative 0.1 to 10 wt%, polyester plasticizer 0.2 to 10 wt%, the rust preventive solution consisting of the balance solvent, An insulating coating layer is formed on the outer periphery of the hard copper stranded 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 pull-out test is not preferable. Conversely, 0.1
When the content is less than 10% by weight, it is difficult to obtain a sufficient anticorrosion effect because the protective effect against the formed corrosion resistant film is lacking. The preferred addition amount of the polyester plasticizer is 0.5 to 7% by weight.

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 to be 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, and such a solvent is methyl alcohol. Alcohol-based solvents such as ethyl alcohol and isopropyl alcohol are preferable, but not limited to alcohol-based solvents.

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 methylbenzotriazole cyclohexylamine salt. Can also be used.

〔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 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.

(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 10 cm insulator was peeled off at 30 cm from one end, and the same pulling load as 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, the amount of adipic acid-based polyester blended is large, so 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 adipic acid-based polyester is small, the role as a protective film on the corrosion resistant film with copper is insufficient. Comparative Example 4,
Considering the comparison of Examples 5, 6 and 7 with Examples 3 and 4, the use of silicone oil, liquid paraffin, polybutene, electric insulating oil and the like in Comparative Example and the use of the polyester plasticizer in Example are It can be seen that there is a large difference in the results in the corrosion resistance test (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 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, 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 that is dispersed and included in liquid paraffin or polybutene is used, it is extremely difficult to form a corrosion resistant film with copper. When it is removed with a solvent and immersed in an aqueous solution of sodium sulfide, it is presumed that it clearly turns black because it lacks resistance to the corrosive environment.

In addition, in the adhesion test in which the insulator was peeled off at one end of 30 cm, it was found that although the amount is not shown in Table 1 in detail, it begins to decrease when the amount of the plasticizer exceeds 0.3% by weight.

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 ^-5 g / It has been found that when it is less than cm ^2, it can withstand pulling out of 30 cm-1 ton, and when it exceeds this, it cannot withstand.

〔The invention's effect〕

As described above, according to the manufacturing method of the present invention,
When a rust preventive solution containing benzotriazole or / and a benzotriazole derivative 0.1 to 10% by weight, a polyester plasticizer 0.2 to 10% by weight, and the remainder being a solvent is applied to the surface of a hard copper twisted wire, copper is present in the presence of the solvent. A rust preventive film is formed favorably on the surface by a chelate bond with a rust preventive component, and if the solvent is volatilized, the polyester plasticizer contained is formed as a protective film on the rust preventive film, and a double rust preventive The effect is enhanced and the corrosion resistance is improved. Moreover, by applying the polyester plasticizer in an amount of 0.2 to 10% by weight, the viscosity of the polyester plasticizer film remaining on the copper wire is adjusted and made uniform, and the coating on the copper wire is made. Since the rust preventive film 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. The problem of discoloration of the stranded conductor during storage and storage of the electric wire can be sufficiently prevented, and even if corrosive rainwater enters from the end of the wire after it is installed as an insulated wire for outdoor use, stress corrosion cracking will occur. The effect is great because there is no fear of causing it.

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.

Front page continued (72) Inventor Chikashi Taketani 2-3-1 Iwata-cho, Higashi-Osaka City, Osaka Prefecture Tatsuta Electric Wire Co., Ltd. (56) Reference JP-A-61-277120 (JP, A) JP 61-195290 (JP, A) JP-A-1-281608 (JP, A)

Claims (2)

[Claims] 1. A rust preventive solution comprising benzotriazole or / and a benzotriazole derivative in an amount of 0.1 to 10% by weight, a polyester plasticizer in an amount of 0.2 to 10% by weight, and the balance being a solvent, is applied to the surface of a hard copper twisted wire, A method for manufacturing an insulated wire, comprising forming an insulating coating layer on the outer periphery of a hard copper stranded wire. 2. A mixture having a ratio of benzotriazole or a derivative thereof to a polyester plasticizer in the range of 0.1: 0.2 to 10: 0.3 on the surface of the twisted wire in contact with the insulator is 3.0 × 10 ⁻⁵ g. /
An insulated electric wire, characterized in that it is applied in an actual amount of less than cm ² .