JPH0687382B2 - 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 phosphoric 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 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, After coating a rust preventive solution containing a phosphoric 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 phosphoric acid plasticizer than the rust preventive solution. The rust preventive solution is applied by further reducing the added amount of 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 reason why the amount of the phosphoric acid-based plasticizer used is 2 to 70% by weight is that 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 phosphoric acid-based plasticizer added to the surface of the stranded wire is 0 to 20 rather than the rust preventive solution.
More specifically, applying the rust preventive solution which has been further reduced by weight% is, in concrete terms, in the manufacturing process of 19 pieces of hard copper concentric stranded wire, a center wire, 6 lower twisted strands and 12 upper twisted strands If a rust preventive solution containing a large amount of phosphoric acid-based plasticizer is applied to each of the twisted wires, a thick protective film of phosphoric acid-based plasticizer remains on the surface of the 12 twisted upper wires. The adhesion between the insulator and the stranded copper wire is reduced, which is not preferable. Therefore, the amount of phosphoric acid-based plasticizer should be reduced to 0 before coating the insulator on the hard copper stranded wire.
Approximately 20% by weight of rust preventive solution is appropriately selected and applied, and then dried quickly to reduce the thickness of the protective film of phosphoric acid plasticizer remaining on the 12 twisted strands in contact with the insulator to a thin state. Reform,
Furthermore, corrosion resistance is imparted to improve the adhesion between the insulator and the hard copper stranded wire.

Also, in the manufacturing process of hard copper concentric stranded wire, when using the one close to the lower limit of the phosphoric acid plasticizer amount in the rust preventive solution to be applied, before coating the insulator, adjust the phosphoric 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 phosphoric acid type plasticizer to ensure excellent corrosion resistance.

As described above, before coating the insulator, the addition amount of the phosphoric 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 twisted wire is contained in the rust preventive solution (addition amount of the phosphoric acid plasticizer of 2 to 70% by weight) applied in the first step. Since there is a certain amount of phosphoric acid plasticizer present, in the second step, that is, before coating the insulator, a rust preventive solution containing no phosphoric acid plasticizer is provisionally applied to the top twisted wire. Even if applied to the surface, as described above, the phosphoric acid-based plasticizer contained in the rust preventive solution applied in the first step remains (although it cannot be completely wiped off, it can be said to be a trace amount), This works synergistically with benzotriazole and / or benzotriazole derivatives to induce sufficient rust prevention effect, and also to insulate This is because improving adhesion between the hard copper stranded wire. Therefore, when the amount of the phosphoric acid plasticizer added is from the specified upper limit to an intermediate amount of the rust preventive solution, for example, the hard copper wire that is 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 and is 0% by weight, the desired rust preventive effect and good adhesion can be obtained as expected.

The phosphoric acid-based plasticizer used in the present invention includes trimethyl phosphate, tributyl phosphate, tri- (2-ethylhexyl) phosphate, 2-ethylhexyl diphenyl phosphate, tributoxyethyl phosphate, triphenyl phosphate, cresyl phosphate. Diphenyl phosphate, isodecyl diphenyl phosphate, tricresyl phosphate, tritolyl
One or more of these groups can be used, such as phosphates, trixylenyl phosphates, alkyl allyl phosphates, and the like.

The solvent used is used for facilitating the dissolution and mixing of the benzotriazole or / and the benzotriazole derivative and the phosphoric acid-based plasticizer, and for adjusting the stickiness of the phosphoric acid-based plasticizer. Alcoholic solvents such as methyl alcohol, ethyl alcohol, isopropyl alcohol and trichloroethane are preferred,
It is 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.

[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 phosphoric 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 phosphoric acid 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 rust preventive solution in which the addition amount of the phosphoric acid-based plasticizer is further reduced to 0 to 20% by weight is appropriately selected, and the rust preventive solution is applied onto the upper twisted wire in contact with the insulator and is quickly dried to leave the phosphorus on the upper twisted wire. The phosphoric acid-based plasticizer remaining in the upper twisted wire in contact with the insulator is adjusted so that the viscosity of the acid-based plasticizer film is adjusted and made uniform, 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.

In other words, if the amount of phosphoric acid plasticizer added to the rust preventive solution is large (however, it is not preferable to exceed 70% by weight),
Although the rust-preventing effect and corrosion resistance are achieved in a desirable state as expected, on the other hand, after coating, the film of phosphoric acid plasticizer remaining on the upper twisted wire in contact with the insulator inevitably becomes thicker, so it was used as an insulated wire. At this time, the adhesion between the insulator and the upper stranded wire is lowered, and the insulator is pulled out during the overhead wire, 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 addition amount of the phosphoric acid plasticizer is further reduced to 0 to 20% by weight than that of the solution, in other words, the first application that enhances 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 with a high concentration of phosphoric acid plasticizer is due to the rust preventive solution applied in the second rust preventive treatment. Of the phosphoric acid plasticizer remaining on the upper stranded wire in contact with this insulator by thinning it as much as possible and applying it again to the upper stranded wire in contact with this insulator. The thickness of the film is modified to a thin state, and corrosion resistance is added to adhere the insulation to the twisted wire. Because and improves the improvement improved anticorrosive effects impair the adhesion to the upper stranded wire in contact with the insulating member, brilliantly solves the conflicting requirements that could successfully achieve the intended purpose.

〔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, the rust preventive solution having a phosphoric acid-based plasticizer amount of 0 to 20% by weight was applied to the twisted copper wire in contact with the insulator before the insulating coating, Since the amount of the phosphoric acid-based plasticizer in the rust preventive solution remaining on the wire surface is adjusted to be equal to or lower than the critical point of 40% by weight, 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 twisted copper strands on the insulator, the adhesion between the conductor and the insulator is deteriorated even though it has corrosion resistance, and the conductor extraction test is not preferable. 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 phosphoric acid-based plasticizer added in 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 phosphoric acid-based plasticizer in the rust preventive solution to be applied exceeds the critical amount, so that it is not suitable for the conductor extraction 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.

 ─────────────────────────────────────────────────── ─── 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 and a phosphoric acid plasticizer 2 to 70 on the surface of a center wire, a lower twisted wire and an upper twisted wire in a hard copper twisted wire.
After applying a rust preventive solution consisting of a solvent and the balance being a solvent, the amount of the phosphoric acid plasticizer added to the surface of the upper twisted wire is 0 to 20 wt% more than the rust preventive solution before coating the insulator. %, A method for producing an insulated wire, characterized by applying a rust preventive solution further reduced.