JPH07105171B2 - Insulated wire and its anticorrosion agent - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a vinyl insulated electric wire which is laid across outdoors.
The present invention relates to an insulated wire that prevents the stress corrosion breakage and an anticorrosive agent for the insulated wire.

[Conventional technology and its problems]

Residual stress is generated in the conductor of this type of insulated wire during the drawing or twisting process, and if rainwater enters the insulated wire (between the conductor and its covering insulator), the residual stress causes The so-called stress corrosion, which promotes the corrosion of the conductor due to the corrosive substance (sulfide) therein, occurs. This stress corrosion occurs intensively in the missing part of the conductor and leads to disconnection. This phenomenon is widely known as stress corrosion breakage.

As measures for preventing this stress corrosion disconnection, there are conventionally the following.

The twisted conductor is rolled and compressed, and the residual stress due to tension and the residual stress due to bending generated during twisting are converted into compressive stress to prevent stress corrosion.

A watertight compound is filled in the gap between the conductor and the insulator to prevent water from entering the gap.

On the conductor, benzotriazole (BTA) or a reaction product of BTA and amine is applied as an anticorrosive agent (antisulfurizing agent).

Apply a mixture of BTA and epoxy-based, phthalic-acid-based or phosphoric-acid-based plasticizer on the conductor.

However, the above measures are not effective because they do not prevent corrosion itself. As for the means, the work of filling the watertight compound is very troublesome and the productivity is poor. Although the means are effective for directly preventing corrosion of the conductor,
The prevention effect is inferior to the means.

For this reason, the measure is most effective, but when the insulator covering the conductor is a vinyl chloride (PVC) composition, the plasticizer migrates (is eaten) to the PVC composition and is resistant to sulfide. Is damaged and the conductor is corroded by the water.

This mechanism is due to the fact that PVC composition has dioctyl phthalate (DOP) and salt para (chlorinated paraffin) from the beginning.
Although plasticizers such as are mixed, in a general mixing amount,
Since PVC is not saturated and has good compatibility with the plasticizer, it absorbs more and more when it comes into contact with the plasticizer. Therefore, the plasticizer applied on the conductor forms an insulator.
It is believed to be eaten by PVC compositions.

In view of the above, it is an object of the present invention to effectively prevent stress corrosion due to water immersion in an insulated wire of which the insulator is a PVC composition.

[Means for Solving the Problems of the Invention]

In order to solve the above problems, in the anticorrosive agent according to the present invention, BTA is used in the same manner as the above means, but an epoxy system is used as the plasticizer, and they are reacted. There is, for example, the following general formula.

The anticorrosive agent consisting of this general formula has the following reaction formula (plasticizer:
For example, epoxidized soybean oil W100EL). In this reaction formula, BTA and W100EL react in the absence of solvent (catalyst) and under heating, and are heated to, for example, about 130 ° C ± 10 ° C. When a solvent is used, any solvent can be used as long as it can dissolve both, for example, tetrahydrofuran (THF) is used. In this case, it may be at room temperature,
It is preferable to heat, for example, to about 60 ° C. or higher. The weight ratio of the solvent to both is appropriately set by experiments or the like in consideration of reactivity, corrosion resistance and the like.

This anticorrosive is non-migratory (plasticizer is not eaten),
An insulated wire in which this is applied to a conductor is according to the present invention. That is, a reaction product of benzotriazole and an epoxy plasticizer is applied to the surface of a hard copper wire, and the hard copper wire is coated with a vinyl chloride composition.

[Action]

In the insulated wire constructed as described above, since the non-migrating anticorrosive agent is applied, the plasticizer does not migrate to the PVC insulated wire. Therefore, the resistance to sulfide does not deteriorate.

〔Example〕

First, W100EL and BTA were reacted and polymerized under the conditions of no solvent and 130 ± 10 ° C at the weight ratio shown in Table 1 (molar ratio in parentheses). Reaction BTA,
A reaction product consisting of reaction BTA and reaction W100EL was obtained, which was further dissolved in a solvent to prepare a stock solution of an anticorrosive agent.

The average molecular weight of W100EL is about 1000 and the number of epoxy groups is about 4. Therefore, if BTA and W100EL are completely reacted and polymerized, the reaction molar ratio is about 4: 1.

Next, the above stock solution is diluted 20 times with 1, 1, 1 and trichloroethane, and first, in the step of rewinding the 2.0 mmφ hard copper wire 1 into a bobbin for twisting wire, the diluted stock solution a is applied by drip coating.
As shown in the figure, when the 19 hard copper wires are twisted concentrically, the diluted undiluted solution a is again applied by drip at the time of 7 twists in the center and 19 twists of the outer layer, and the twisted conductor 2 ( 60 mm ² hard copper stranded wire), an insulating coating 3 made of a PVC composition was applied by known extrusion molding to obtain an insulated wire P.

[Confirmation of effect]

The insulated electric wire P obtained as described above (Example 1, shown in Table 1,
2 or 3 times 20 times diluted solution a is applied to conductor 2 by drip coating)
Samples each having a length of 100 mm were sampled from the sample, the insulator 3 of each sample was peeled off, and each conductor 2 was immersed in a 100 ppm sodium sulfide aqueous solution (20 ° C.) for 30 seconds.
When visually observing the presence or absence of discoloration of each conductor 2, no abnormality was found.

The sample taken in the same manner as above was left for 30 days in a constant temperature bath of 80 ± 1 ° C, then taken out and the insulator 3 was peeled off. After immersing the conductor 2 for 30 seconds, the presence or absence of discoloration of the conductor 2 was observed, and no abnormality was observed.

By the way, as in the above method, BTA mixed with W100EL and dissolved in isoprypyl alcohol was applied and left in a thermostatic layer at 80 ± 1 ° C for 30 days, and the conductor was heated to the sodium sulfide. When immersed in an aqueous solution for 30 seconds,
When the plasticizer was eaten by the PVC composition, the resistance to sulfide was lost and discoloration was observed.

〔effect〕

Since the present invention is configured as described above, even if the insulator is a PVC composition, the resistance of the conductor to sulfide is maintained and corrosion is effectively prevented. Therefore, according to the present invention, it is possible to provide a highly reliable insulated wire for a long period of time.

[Brief description of drawings]

The drawing is a partially cutaway perspective view of an embodiment of the insulated wire according to the present invention. 1 ... Hard copper wire, 2 ... Conductor, 3 ... Insulator (PVC composition), a ... Reaction product coating solution (diluting solution, anticorrosive agent), P ... Insulated wire.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Nobuhiro Fujio 2-3-1 Iwata-cho, Higashi-Osaka City, Osaka Prefecture Tatsuta Electric Wire Co., Ltd. No. 1 in Tatsuta Electric Wire Co., Ltd. (72) Inventor Tsutomu Murao 2-3-1, Iwata-cho, Higashi-Osaka City, Osaka Prefecture Within Tatsuta Electric Wire Co., Ltd. (56) Reference JP-A-61-277120 (JP, A) ) JP-A-61-262595 (JP, A) JP-A-1-281609 (JP, A)

Claims (2)

[Claims] 1. An insulated wire comprising a hard copper wire coated with a reaction product of benzotriazole and an epoxy plasticizer on the surface of the hard copper wire, and a vinyl chloride composition coated on the hard copper wire. 2. An anticorrosive agent for an insulated wire having the following general formula.