JPH0687381B2 - 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]

As a result of intensive studies to solve the above problems, the present inventors have found that the amount of phthalic acid-based plasticizer in a rust preventive solution applied to a copper wire in contact with an insulator is 40% by weight in order to adapt to conductor extraction. The present invention has been completed by finding that it is at the critical point of%.

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 on the surface of a center wire, a lower twisted wire and an upper twisted wire in a hard copper twisted wire, and a tar. After applying a rust preventive solution consisting of an acid plasticizer of 2 to 70% by weight and the remainder being a solvent, and before coating an insulator, the surface of the twisted wire is more phthalic acid plasticizer than the rust preventive solution. This is to apply a rust preventive solution whose addition amount is further reduced to 0 to 20% by weight.

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 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 conductor pull-out test is not preferable. On the other hand, if it is less than 2% by weight, it is difficult to obtain a sufficient rust-preventing effect because it lacks a protective action for the corrosion-resistant film to be formed.

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 phthalic acid-based plasticizer added to the surface of the twisted wire is more than that of the rust preventive solution.
More specifically, applying the anticorrosive solution which has been further reduced to 20% by weight is specifically described. In the manufacturing process of 19 hard copper concentric stranded wires, the center wire, 6 lower twisted wires and 12 If a rust-preventive solution containing a large amount of phthalic acid-based plasticizer is applied to each of the twisted strands of the upper strand, a thick protective film of the phthalic acid-based plasticizer remains on the surface of the 12 strands of the upper twisted strands. If it is applied, 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, appropriately select and apply a rust preventive solution with a phthalic acid plasticizer amount of 0 to 20% by weight, dry it quickly, and contact with the insulator 12 pieces The thickness of the protective film of the phthalic acid-based plasticizer remaining on the twisted strand is modified to a thin state, and corrosion resistance is imparted to improve the adhesion between the insulator and the hard copper strand.

Also, in the manufacturing process of hard copper concentric stranded wire, when using the one near the lower limit of the phthalic acid plasticizer amount in the rust preventive solution to be applied, before coating the insulator, the phthalic acid plasticizer amount A 20% by weight rust preventive solution is applied on the twisted strands to complement the rust preventive film and to provide a protective film with a phthalic acid plasticizer to ensure excellent corrosion resistance.

As described above, before coating the insulator, the addition amount of the phthalic acid-based plasticizer of the rust preventive solution applied to the surface of the twisted wire (twisted strand) may be 0% by weight. As described in detail above, the surface of the so-called upper twisted wire has the rust-preventive solution applied in the first step (the addition amount of the phthalic acid-based plasticizer is 2
~ 70 wt%), there is a certain concentration of phthalic acid-based plasticizer, so in the second step, that is, before coating the insulator, phthalic acid-based plasticizer is not used at all. Even if the rust preventive solution not containing is applied to the surface of the upper twisted wire, as described above, the phthalic acid-based plasticizer contained in the rust preventive solution applied in the first step is not completely wiped off. It remains, albeit in a very small amount, and this is benzotriazole or /
This is because they work synergistically with the benzotriazole derivative to induce a sufficient rust preventive effect, and also improve the adhesion between the insulator and the hard copper stranded wire. Therefore, when the amount of the phthalic acid-based plasticizer to be added is particularly from the specified upper limit to an intermediate amount of the rust preventive solution, the hard copper wire, that is, the upper twisted wire, which comes into contact with the insulator before coating the insulator is used. Even if the amount of the plasticizer in the anticorrosion solution applied to, is 0% by weight, as expected,
A favorable rust preventive effect and good adhesion can be obtained.

The phthalic acid-based plasticizer used in the present invention includes dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dioctyl phthalate, di-n-octyl phthalate, higher alcohol phthalate, diisooctyl phthalate,
Diisobutyl phthalate, dihebutyl 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. One or more members of the group 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 phthalic acid-based plasticizer, and adjusting the stickiness of the phthalic acid-based 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 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 phthalic acid plasticizer 2 to 70% by weight, and a balance of an rust preventive solution consisting of alcohol as a solvent is hard copper twisted. When applied to the surface of the center line and the lower twisted wire and the upper twisted wire in the wire, in the presence of alcohol, a rust preventive film is formed favorably on the copper surface by a chelate bond with a rust preventive component, and if the alcohol volatilizes,
The contained phthalic acid-based plasticizer is formed as a protective film on the rust-preventive film, the double anti-rust 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 phthalic solution in which the amount of the phthalic acid-based plasticizer added is further reduced to 0 to 20% by weight is appropriately selected and applied on the upper twisted wire in contact with the insulator, and quickly dried to leave it on the upper twisted wire. The phthalic acid-based plasticizer remaining in the upper twisted wire in contact with the insulator is used because the acid-based plasticizer film is adjusted in stickiness and uniformized, and the rust preventive film on the upper twisted wire is complemented at the same time. Even if the film thickness is slightly different, it can meet severe corrosion resistance and conductor pull-out tests and can prevent stress corrosion breakage.

That is, if the amount of phthalic acid-based plasticizer added to the rust preventive solution is large (however, it is not preferable that the phthalic acid plasticizer exceeds 70% by weight), the rust preventive effect and the corrosion resistance can be achieved in a desired state as desired, but After coating, the film of the phthalic acid-based plasticizer remaining on the upper twisted wire in contact with the insulator inevitably becomes thicker, so when it is used as an insulated wire, the adhesion between the insulator and the upper twisted wire is reduced, The insulator is 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 for applying an anticorrosive solution in which the addition amount of the phthalic acid-based plasticizer is further reduced to 0 to 20% by weight compared to the solution, in other words, the first application for enhancing the antirust effect is 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 phthalic acid plasticizer is due to the rust preventive solution applied in the second rust preventive treatment. The thickness of the protective film of the phthalic acid-based plasticizer remaining on the twisted wire in contact with this insulator is obtained by thinning the phthalic acid-based plasticizer in (1) and applying it again onto the twisted wire in contact with this insulator. Thickness is modified to a thin state, and corrosion resistance is added to make it an insulator. Since it improves the adhesion with the stranded wire, it solves the conflicting requirements that the improvement of the rust prevention effect impairs the adhesion with the upper stranded wire in contact with the insulator, and successfully achieves the intended purpose. I was able to solve it.

〔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 conductor 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, in Examples 1 to 6, a rust preventive solution having a phthalic acid plasticizer amount of 0 to 20% by weight was applied on the twisted copper wire in contact with the insulator before the insulating coating, Since the amount of the phthalic acid-based plasticizer in the rust preventive solution remaining on the wire surface is adjusted to the critical point of 40% by weight or less, good results are shown in any of the tests, but Comparative Example 1 is in contact with the insulator. Since the rust preventive solution is not applied to the insulator on the twisted copper strands, the conductor pull-out test is unfavorable because the adhesiveness between the conductor and the insulator is deteriorated although it has corrosion resistance. In Comparative Example 2, 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 3, the corrosion resistance test is not preferable because the amount of the phthalic acid-based plasticizer added to the rust preventive solution applied on the center wire, the lower twisted wire and the upper twisted copper wire is insufficient. In Comparative Example 4, the amount of the phthalic acid-based plasticizer in the rust preventive solution to be applied exceeds the critical amount and therefore does not conform to the conductor pull-out test.

〔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.

Front Page Continuation (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 Sho 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 and a phthalic acid plasticizer 2 on the surfaces of a center wire, a lower twisted wire and an upper twisted wire in a hard copper twisted wire.
~ 70 wt%, after applying a rust preventive solution consisting of a solvent, the amount of phthalic acid plasticizer added to the surface of the twisted wire is 0 to more than the rust preventive solution before coating the insulator. A method for producing an insulated wire, which comprises applying an anticorrosive solution further reduced to 20% by weight.