JPH02181316A - Manufacturing method of insulated wire - Google Patents

Abstract

PURPOSE:To obtain an insulated electric cable having a highly corrosion- resistant coating on a twisted conductor by applying a rust preventing solution containing 0-20wt.% of phthalic acid-based plastisizer to the copper strand which contacts with an insulator before the cable is coated with an insulator. CONSTITUTION:Rust preventing treatment is carried out by applying a rust preventing solution on a copper strand while the addition amount of a phthalic acid-based plastisizer being decreased gradually toward the direction from the center of the twisted cable to an insulator to be contacted. Then, before coated with an insulator, the copper strand to have a contact with the insulator is coated with a rust preventing solution containing 0-20wt.% of a phthalic acid-based plastisizer and dried so as to adjust and uniformalize the viscosity of the phthalic acid-based plasticizer remaining on the copper strand. And at the same time, the rust preventing film on the copper strand is complemented. By this method, a sufficiently corrosion-resistant coating is formed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention uses a benzotriazole anticorrosive solution to
The present invention relates to a method for producing insulated wires and power cables in which discoloration of the surface of stranded wires is prevented for a long period of time.

[Conventional technology]

Conventionally, during the storage of copper wires and copper stranded wires, or during the manufacturing process of insulated wires, and during the storage of wires, the surfaces of copper wires and stranded wire conductors may discolor. , copper stranded wires, etc. are coated with an anti-salting solution for copper.

On the other hand, vinyl chloride insulated wire (OW) is used as an outdoor distribution line.
, polyethylene insulated wire (OE), cross-linked polyethylene m-conductor wire (OC), etc. are often used, but a black copper oxide film forms on the surface of the copper wire several years after overlaying, and in rare cases, hard steel r/8 The wire breaks abnormally in a knife cant shape, so-called.
Stress corrosion cracking can occur, which is an important problem in terms of power safety.

This stress corrosion cracking occurs when rainwater enters the wire from the terminal and accumulates in the wire's voids, condenses and becomes corrosive water that forms a thick black copper oxide film on the surface of the copper wire. The corrosion factor that selectively melts the underlying copper exposed in the parts, and the stress factor such as the bending stress that occurs when processing hard steel stranded wires and the stress that occurs when overhead wires are used against the bending stress that occurs when winding wires in drums. It is said to occur through interaction.

To prevent stress corrosion cracking that occurs in such long-term corrosive environments, applying a solution of benzotriazole in a volatile solvent such as alcohol alone to hard steel strands does not form a sufficient corrosion-resistant film. Therefore, long-term corrosion resistance cannot be expected, and there is a problem of stress corrosion cracking.

Therefore, as a solution, ■ a method of using an insulating layer added with anti-corrosion components for copper, ■ a method of filling a watertight compound into hard steel strands, and ■ a method of dissolving benzotriazole derivatives in liquid paraffin, polybutene, silicone oil, etc. A method has been proposed in which the material is applied onto hard steel strands.

However, regarding (2), there is a problem in that the rust preventive agent is difficult to dissolve from the insulating layer, it is difficult to prevent discoloration of the steel for a long period of time, and there is an undesirable problem that the insulation resistance of the insulating layer decreases. As for (2), there are problems in that the manufacturing cost is high, the removal work of the watertight compound is troublesome, and if the removal is not sufficient, the current conduction characteristics of the connection part are deteriorated. Regarding ■, its use reduces the adhesion between the insulator and the hard steel stranded wire,
There is a problem that the pull-out strength is insufficient.

[Problem that the invention seeks to solve]

The present inventors previously disclosed in Japanese Patent Application No. Sho 63-7869 that a rust preventive solution in which specific amounts of benzotriazole or/and a benzotriazole derivative and a phthalic acid plasticizer were dissolved in a solvent was applied to stranded hard steel wire. However, when the insulated wire is strung together, the strict conductor pull-out test to evaluate the adhesion between the insulator and the hard steel stranded wire is not always satisfactory. I understand.

The present invention was made in view of the above problems, and by applying a rust preventive solution to the hard steel stranded wire, a strong corrosion-resistant film is formed on the surface of the copper wire or hard steel stranded wire. Even if corrosive rainwater enters the stranded wire, it maintains its copper color for a long time.
Another object of the present invention is to provide a method for manufacturing an insulated wire and a power cable that have good adhesion between an insulator and a hard steel stranded wire.

[Means for solving problems]

The inventors of the present invention conducted extensive studies to solve the above problems, and as a result found that it was impossible to adapt the device to conductor extraction, and completed the present invention.

The structure of the present invention is to apply a rust preventive solution consisting of benzotriazole or/and benzotriazole derivative 011 to 10% by weight, 2 to 70% by weight of a phthalic acid plasticizer, and the balance being a solvent to the surface of a hard steel stranded wire. , in the method of forming an insulating coating layer on the outer periphery of the hard steel stranded wire, the amount of the phthalate plasticizer added is gradually decreased from the center of the dielectric toward the direction in contact with the insulator, and before coating the insulator. The amount of the phthalic acid plasticizer added to the antirust solution applied to the copper wire in contact with the insulator is 0 to 20% by weight.

Hereinafter, the configuration of the present invention will be explained in more detail.

The reason why benzotriazole is added in an amount of 0.1 to 10% by weight in the rust preventive solution used in the present invention is that even if 10% by weight or more is added, a corrosion-resistant film is not formed any further, so the rust preventive effect is reduced. Saturation is reached and excessive amounts lead to precipitation, which is not preferred.

On the other hand, if the amount added is less than 0.1% by weight, a sufficient corrosion-resistant film will not be formed, and therefore no rust-preventing effect will be obtained. The preferred amount of benzotriazole added is 1 to 5% by weight.

The reason why the amount of phthalic acid plasticizer used is 2 to 70% by weight is that if it exceeds 70% by weight, it will not have the protective effect of remaining sticky on the stranded wire conductor after application, so sufficient rust prevention effect cannot be obtained. Hard to get caught.

Next, in the configuration of the present invention, the amount of phthalic acid-based plasticity added is gradually decreased from the center of the dielectric toward the direction of contact with the insulator, and the amount of phthalic acid plasticity is applied to the copper wire in contact with the insulator before coating the insulator. In the anti-corrosion solution, the center strand and 6 first-stranded strands were treated with a rust-preventing solution containing a large amount of phthalic acid plasticizer, and the 12 first-stranded strands were treated with an anti-rust solution containing a smaller amount of phthalic acid plasticizer. After applying each rust solution, when coating the insulator on the hard steel stranded wire after application, apply a rust preventive solution containing 0 to 20% by weight of phthalic acid plasticizer and quickly dry. Let me, wAI! By protecting the phthalic acid-based plastic cutting remaining on the 12 stranded strands that come into contact with the body and coating the insulator with a reduced film thickness, the adhesion between the insulator and the hard steel strands can be improved, resulting in excellent corrosion resistance. This is because it can be used as an insulated wire suitable for wiring.

In this case, the center strand, the first twisted strand, and the second stranded strand are respectively coated with a rust preventive solution containing an intermediate amount of the phthalic acid plasticizer shown in the present invention from the specified upper limit. A thick protective film of phthalic acid plasticizer remains on the surface of the 12 ply twisted wires in contact with the insulator, so applying an insulator will reduce the adhesion between the msi body and the hard steel strands, which is undesirable. Therefore, we applied an anti-corrosion solution that does not contain phthalic acid plasticizers to reduce the thickness of the protective film of phthalic acid plasticizers remaining on the 12 twisted wires, thereby improving corrosion resistance. to improve the adhesion between the insulator and the hard steel stranded wire.

Next, in the case of seven hard steel concentric strands, since it is composed of a center strand and six top-twisted strands, the phthalate plasticizer is Although it is possible to apply the additive amount in successive decreases, as an alternative method, if the protective film of the phthalic acid plasticizer remaining on the ply-stranded wire becomes thick due to the application of one type of anti-corrosion solution, it may be difficult to coat the insulator. It is possible to improve the adhesion between the insulator and the hard W4 stranded wire by applying the phthalic acid plasticizer in the anti-rust solution applied to the copper wire in contact with the copper wire in an amount of 0 to 20% by weight. .

For the 19 hard steel concentric stranded wires, if the protective film of the phthalate plasticizer remaining on the ply-stranded strands becomes thicker due to the application of one type of anti-rust solution, the same applies to the 7 concentric stranded wires as described above. This can be done to improve the adhesion between the insulator and the hard steel stranded wire.

The phthalic acid plasticizers used in the present invention include dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dioctyl phthalate, di-n octyl phthalate, higher alcohol phthalate, diisooctyl phthalate, diisobutyl decyl phthalate, dinonyl phthalate, and dinormal alkyl phthalate. Phthalate, benzyl phthalate, dimethoxyethyl phthalate, dimethylcyclohexyl phthalate, alkylbenzyl phthalate, methyl phthalyl glycolate, etc., and one or more of these groups can be used.

The solvent used is used to facilitate dissolution and mixing of benzotriazole or/and benzotriazole derivative and phthalic acid plasticizer, and to adjust the viscosity of the phthalic acid plasticizer. Alcohol solvents such as methyl alcohol, ethyl alcohol, and isopropyl alcohol and trichloroethane are preferred, but are not particularly limited.

In addition to benzotriazole, the present invention uses benzodiazole such as benzotriazole monoethanolamine salt, benzotriazole diethylamine salt, benzotriazole cyclohexylamine salt, benzotriazole morpholine salt, benzotriazole diisopropylamine salt, and methylbenzotriazole cyclohexylamine salt. Triazole derivatives can also be used.

[For production]

Outdoor insulated wires break due to stress corrosion cracking.
That mi! After the wires are installed on the overhead line, corrosive rainwater enters the twisted space of the hard W4 stranded wires inside the wires through small gaps such as the tie-down section, terminal section, or connection section, causing corrosion that accumulates over a long period of time. It is the first meaning. Therefore, the requirements for an outdoor insulated wire are excellent corrosion resistance and good adhesion between the insulator and the copper wire in contact with the conductor pull-out test, which can be conducted under severe conditions during overhead wiring.

Rust preventive solution used in the present invention, i.e. benzotriazole or/and benzotriazole derivative 0.1 to 10
When a rust-preventive solution consisting of 5% fiii%, 2 to 70% by weight hydrofluoric acid plasticizer, and the remainder alcohol as a solvent is applied to the surface of a hard steel stranded wire, in the presence of the alcohol, the rust-preventive component appears on the copper surface. If a rust-preventive film is well formed by the chelate bond of will improve.

However, the amount of phthalic acid plasticizer added in the anti-corrosion solution is large, and the thicker the film of phthalic acid plasticizer that remains on the copper wire in contact with the insulator after application, the harder it is to bond with the insulator when used as an insulated wire. The adhesion with the steel stranded wires decreases, and the insulator is pulled out during overhead wire installation, which is not preferable.

In the manufacturing method of the present invention, during the manufacturing process of the hard steel stranded wire used, a rust preventive solution in which the amount of phthalic acid plasticizer added is gradually reduced from the center of the dielectric toward the direction of contact with the insulator is applied onto the copper wire. Before coating the insulator with anti-corrosion treatment, apply a rust-preventing solution containing 0 to 20% by weight of phthalate plasticizer on the copper wire in contact with the insulator and dry quickly. In this way, the stickiness of the residual phthalic acid plasticizer film on the copper wire is adjusted and made uniform, and the anti-corrosion film on the copper wire is simultaneously supplemented, resulting in severe corrosion resistance and conductor pull-out. It will pass the test and prevent stress corrosion and disconnection.

〔Example〕

Hereinafter, examples according to the present invention and comparative examples will be explained in comparison.

When concentrically twisting 19 hard steel wires with an outer diameter of 2.0 mmφ and covering the outer periphery with polyethylene insulation,
In advance, apply the anti-w # solution of each composition shown in Table 1 to the center strand, 6 pre-twisted copper strands, 12 pre-twisted copper strands, and the surface of the copper strands in contact with the insulator before insulation coating. do. For example, the application of the central strand, 6 pre-twisted strands, and 12 pre-twisted strands is carried out by feeding a fixed amount of anti-rust solution with a micro pump and passing it through a rust-preventing tank equipped with an air wiper. To apply the coating on the surface of the copper wire that is in contact with the insulator, wrap a weighted felt around the stranded wire, pump a fixed amount of anti-rust solution onto the upper end of the wire using a micro pump, and then pass through a hot air dryer to quickly dry it. .

Subsequently, a polyethylene insulator is extruded and coated on the outer periphery.
0111@”Outdoor polyethylene insulated wire was manufactured.

Each obtained insulated wire was subjected to the corrosion resistance test (Note 1, Note 2, Note 3) and induction pullout test (Note 4) described below.
I did it. The results are shown in the bottom row of Table 1.

(Note 1) Cut a 10c+a length sample from an insulated wire with a hacksaw, remove the insulator, and immerse the conductor wire in a sodium sulfide aqueous solution with a concentration of 1100 pp for 30 seconds at room temperature, then take it out and check for discoloration on the surface of the conductor wire. The condition was visually observed to determine whether the corrosion resistance was good or bad.

(Note 2) After cutting a 10 cm long sample from the insulated wire with a hacksaw, peeling off the insulator and taking out the hard steel stranded wire, washing off the anti-rust solution adhering to the surface of the conductor wire with a solvent. After being immersed in a sodium sulfide aqueous solution having a concentration of 1100 pp for 30 seconds at room temperature, the wires were taken out and the discolored state of the conductor wire surface was visually observed to determine whether the corrosion resistance was good or bad.

The evaluation criteria for (Note 1) and (Note 2) were as follows: Q mark indicates no discoloration, Δ mark indicates slight discoloration, and X mark indicates clear discoloration.

(Note 3) Cut a 30c+w length sample from an insulated wire with a hacksaw, and add it to an ammonia aqueous solution with a concentration of 1100pp.
After being immersed in a corrosive environment for 8 weeks, the sample was removed, the insulator was stripped off, and the conductor was removed. The average and film thickness of the copper oxide formed on the surface were determined, and the quality of the corrosion resistance was determined based on the values.

The evaluation criteria were as follows: Q mark indicates that the film thickness is less than 0.2 μm, Δ mark indicates that the film thickness is in the range of 0.2 to 0.3 μm, and x mark indicates that the film thickness exceeds 0.3 μm.

(Note 4) Cut a 3m long sample from an insulated wire with a hacksaw.
The conductor and insulator were separated by 0.3 m at one end, fixed at the other end, and a load of 1 ton (pulling load) was applied to the insulator at one end. A judgment was made as to whether the adhesion was good or bad.

The evaluation criteria were as follows: O mark is difficult to pull out, Δ mark is slightly pullable, and x mark is largely pullable.

As can be seen from the results, in Examples 1 to 7, a rust preventive solution containing 0 to 20% by weight of a phthalate plasticizer was applied to the ply-twisted copper wire in contact with the insulator before insulation coating, and the copper Good results are shown even with rust prevention remaining on the surface of the wire, but Comparative Example 1
Because no anti-corrosion solution is applied to the ply-stranded copper wires in contact with the insulator before insulation, the adhesion between the conductor and the insulator is reduced, making the conductor pullout test undesirable, even though it has corrosion resistance. In Comparative Example 2, the amount of benzotriazole added is small, so a sufficient corrosion-resistant film is not formed on the copper surface, which is not preferable. Corrosion resistance test is not preferred because the amount of phthalic acid plasticizer added is insufficient.

Comparative Example 4 does not meet the □ conductor pullout test because the amount of phthalic acid plasticizer in the applied anticorrosive solution exceeds the critical amount.

〔Effect of the invention〕

As explained above, according to the manufacturing method according to the present invention,
Since it is possible to obtain an insulated wire that has good adhesion to the ply-stranded copper wire in contact with the wA edge and has an excellent corrosion-resistant film and protective film on the stranded wire conductor, it is possible to obtain an insulated wire that has good adhesion to the ply-stranded copper wire that is in contact with the wA edge and has an excellent corrosion-resistant film and protective film on the stranded wire conductor. In addition to sufficiently preventing the problem of discoloration of stranded wire conductors during storage of wires and wires, stress corrosion cracking can be prevented even if corrosive rainwater enters from the terminals of the wires after they are installed as outdoor insulated wires. The effect is great because there is no need to worry.

Claims (1)

[Claims] After applying a rust preventive solution consisting of 0.1 to 10% by weight of benzotriazole or/and benzotriazole derivative, 2 to 70% by weight of a phthalic acid plasticizer, and the balance being a solvent to the surface of the hard steel stranded wire, In a method of forming an insulating coating layer around the outer periphery of stranded wires, the amount of phthalic acid plasticizer added is gradually decreased from the center of the dielectric toward the direction in which it contacts the insulator, and the amount of phthalic acid plasticizer added is gradually reduced from the center of the dielectric to the direction in which it contacts the insulator, and the amount of phthalic acid plasticizer added is gradually reduced from the center of the dielectric to the direction in which it contacts the insulator. The amount of phthalic acid plasticizer added in the rust prevention solution applied to copper wire is 0 to 2.
A method for manufacturing an insulated wire, characterized in that the coating is applied at 0% by weight.