JPH0687376B2 - 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.

[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 (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]

Therefore, 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 of epoxy on the surface of a center wire or / and a lower twisted wire in a hard copper twisted wire, an epoxy resin. Plasticizer 0.2〜
After applying a rust preventive solution consisting of 10% by weight and the remainder being a solvent, and then applying a rust preventive solution having a relatively smaller amount of the epoxy plasticizer compounded than the rust preventive solution on the surface of the twisted wire,
Before coating the insulator, a rust preventive solution in which the amount of the epoxy plasticizer added is further reduced to 0 to 0.3% by weight as compared with the rust preventive solution is applied to the surface of the upper twisted 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. When the amount of the epoxy plasticizer used is 0.2 to 10% by weight, if it is 10% by weight or more, stickiness remains on the stranded wire conductor after coating and the conductor pull-out test is not preferable. Conversely, 0.2
If the content is less than 10% by weight, it is difficult to obtain a sufficient rust preventive effect because the protective effect against the formed corrosion resistant film is lacking.

Next, in the configuration of the present invention, as described above, the rustproofing solution is applied to the surface of the center wire or / and the lower twisted wire in the hard copper twisted wire, and then the surface of the upper twisted wire is more than the rustproof solution. After applying a rust-preventive solution having a relatively small amount of the epoxy-based plasticizer, before finally covering the insulator, the surface of the upper twisted wire is more than the rust-preventive solution in the epoxy-based plasticizer. The concrete explanation is to apply the rust preventive solution whose amount is further reduced to 0 to 0.3% by weight. In the manufacturing process of 19 hard copper concentric stranded wires, the central strand and 6 lower twists are applied. The wires are coated with a rust preventive solution containing a large amount of epoxy plasticizer, and the 12 twists of the rust preventive solution containing less epoxy plasticizer than the former are applied. When coating, the rust preventive solution with an epoxy plasticizer content of 0 to 0.3% by weight is appropriately selected. Coating and quick-drying, the protective coating of the epoxy plasticizer remaining on the 12 twisted strands in contact with the insulator is reduced to cover the insulator, and the adhesion between the insulator and the hard copper stranded wire This is because it is possible to obtain an insulated wire having excellent corrosion resistance and suitable for crossing.

In this case, the amount of the epoxy plasticizer shown in the present invention is applied from the specific upper limit to the intermediate amount of the rust-preventive solution, which are respectively applied to the central wire, the lower twisted wire and the upper twisted wire,
Since the protective film of the epoxy plasticizer remains thickly on the surface of the 12 twisted strands in contact with the insulator, it is not preferable to apply the insulator because the adhesion between the insulator and the hard copper stranded wire is reduced. Therefore, by applying an anticorrosive solution without adding an epoxy plasticizer, the thickness of the protective film of the epoxy plasticizer remaining on the 12 twisted strands was modified to a thin state to further impart corrosion resistance. To improve the adhesion between the insulator and the stranded copper wire.

Next, in the case of 7 pieces of hard copper concentric stranded wire, since it is composed of the center element wire and 6 pieces of upper twisted element wire, the epoxy plasticizer is added from the center of the stranded conductor toward the direction of contact with the insulator. It is also possible to successively reduce the amount of addition.

As described above, the reason why the addition amount of the epoxy-based plasticizer of the rust preventive solution applied to the surface of the upper twisted wire (upper twisted wire) before coating the insulator is 0% by weight is sufficient. As described in detail above, the surface of the so-called twisted wire is coated with the rust-preventive solution applied in the first step (the amount of the epoxy plasticizer added is 0.2 to 1).
(0% by weight), there is a certain concentration of the epoxy plasticizer present, so in the second step, that is, before coating the insulator, the epoxy plasticizer containing no epoxy plasticizer at all is assumed. Even if the rust solution is applied to the surface of the upper twisted wire, as described above, the epoxy plasticizer contained in the rust preventive solution applied in the first step (cannot be completely wiped off but can be said to be a very small amount. )
This is because they remain, and these act synergistically with the benzotriazole and / or the benzotriazole derivative to induce a sufficient rust preventive effect, and at the same time, improve the adhesion between the insulator and the hard copper stranded wire. Therefore, when the amount of the epoxy plasticizer to be added, particularly when using an anticorrosive solution of an intermediate amount from the specific upper limit, the hard copper wire 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 to be applied to is 0% by weight, the desired rust preventive effect and good adhesion can be obtained as expected.

Epoxy plasticizers used in the present invention include epoxidized soybean oil, epoxidized linseed oil, epoxidized castor oil, epoxidized unsaturated fats and oils such as epoxidized linseed oil, epoxidized linseed oil fatty acid butyl, octylepoxy steer. rate,
Epoxidation of epoxybutyl stearate, epoxidized fatty acid monoester, epoxidized oleic acid octyl ester, epoxidized oleic acid decyl ester, epoxy monoester, alkyl epoxy stearate, n-alkyl epoxy stearate, isoalkyl epoxy stearate, etc. Unsaturated fatty acid esters, di-2-ethylhexyl epoxyhexahydrophthalate, diisodecyl epoxyhexahydrophthalate, epoxycyclohexane derivatives such as cycloalkylepoxystearate, and epichlorohydrin derivatives, etc. One or more of these groups 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 epoxy plasticizer and for adjusting the stickiness of the epoxy plasticizer. As such a solvent, methyl alcohol is used. Alcohol solvents such as ethyl alcohol and isopropyl alcohol and trichloroethane are preferable, 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.

The anticorrosive solution used in the present invention, that is, 0.1-10% by weight of benzotriazole or / and benzotriazole derivative, 0.2-10% by weight of an epoxy plasticizer, and the balance of the anticorrosive solution consisting of alcohol as a solvent are hard copper stranded wires. When applied to the center line or / and the surface of the lower twisted wire in, 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 epoxy plasticizer is formed as a protective film on the rust-preventive film to enhance the double anti-rust effect and improve the corrosion resistance.

Further, the rustproofing solution is applied to the surface of the center wire or / and the lower twisted wire in the hard copper twisted wire, and then the compounding amount of the epoxy plasticizer is relatively applied to the surface of the upper twisted wire as compared with the above antirust solution. After applying the reduced rust preventive solution and before finally covering the insulator, the amount of the epoxy plasticizer added to the surface of the upper twisted wire is further reduced to 0 to 0.3% by weight compared with the rust preventive solution. Apply the rust preventive solution that has been soaked and dry it quickly to adjust the viscosity of the epoxy plasticizer film left on the upper twisted wire and make it uniform,
Moreover, since the rust preventive film on the upper twisted wire is complemented at the same time, it is possible to meet severe corrosion resistance and a conductor pull-out test and prevent stress corrosion breakage.

In other words, if the amount of epoxy plasticizer added to the rust preventive solution is large (however, it is not preferable to exceed 10% by weight), the rust preventive effect and corrosion resistance can be achieved in a desired state as expected, but After that, the film of the epoxy plasticizer remaining on the upper twisted wire that contacts the insulator inevitably becomes thicker,
When it is used as an insulated wire, the adhesion between the insulator and the upper twisted wire is lowered, and the insulator is pulled out during the overhead wire, which causes an undesirable problem.

In this respect, according to the present invention, as described above, before coating the insulator, the surface of the upper twisted wire is treated with a rust preventive solution which is first applied to the center line or / and the lower twisted wire of the hard copper twisted wire. Also, after applying a rust preventive solution containing a relatively small amount of the epoxy plasticizer, before finally covering the insulator, the surface of the upper twisted wire is an epoxy plasticizer more than the rust preventive solution. By applying a means of applying an anticorrosive solution in which the addition amount of is further reduced to 0 to 0.3% by weight, in other words, the first application that enhances the anticorrosion effect has a high concentration of the epoxy plasticizer. The problem of slippage that occurs between the insulator and the twisted wire in contact with the rust preventive solution is that the epoxy plasticizer in the rust preventive solution applied in the second rust preventive treatment is as much as possible. Thinly and apply it again on the twisted wire that contacts this insulator. To improve the adhesiveness between the insulator and the upper stranded wire by modifying the thickness of the protective film of the epoxy plasticizer remaining on the upper stranded wire in contact with this insulator to a thin state and further providing corrosion resistance. Therefore, the contradictory requirement that the improvement in rust prevention effect impairs the adhesion with the upper stranded wire in contact with the insulator was successfully solved, and the intended purpose was successfully achieved.

〔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 induction 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, Examples 1 to 5 show good results in all tests, but Comparative Example 1 does not apply the rust preventive solution on the twisted copper wire in contact with the insulator before the insulation. Therefore, although it has corrosion resistance, the adhesion between the conductor and the insulator decreases, and the conductor pull-out test is not preferable. In Comparative Example 2, although the epoxy plasticizer film remaining on the twisted copper wire is thick, the addition amount of the epoxy plasticizer in the rust preventive solution applied before insulation is not appropriate, so that the conductor and the insulator are Adhesion is reduced and the conductor pull-out test becomes unfavorable. In Comparative Example 3, 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 4, since the epoxy-based plasticizer film remaining on the upper-twisted copper wire is extremely thick, even if the rust preventive solution to which the epoxy-based plasticizer applied before insulation is not applied is applied, the upper-twisted copper wire is applied. The adjustment and homogenization of the viscosity of the epoxy plasticizer film to be left appropriately become insufficient, and the conductor pull-out test becomes unfavorable. In Comparative Example 5, the corrosion resistance test is not preferable because the amount of the epoxy plasticizer added in the rust preventive solution applied on the center wire, the lower twisted and the upper twisted copper strands is not appropriate.

〔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 on the surface of a center wire or / and a lower twisted wire in a hard copper stranded wire, and an epoxy plasticizer of 0.2 to
After applying a rust preventive solution consisting of 10% by weight and the remainder being a solvent, and then applying a rust preventive solution having a relatively smaller amount of the epoxy plasticizer compounded than the rust preventive solution on the surface of the twisted wire,
Before coating the insulator, the surface of the upper twisted wire is coated with a rust preventive solution in which the addition amount of the epoxy plasticizer is further reduced to 0 to 0.3% by weight compared to the rust preventive solution. Insulated wire manufacturing method.