JPS58103705A - Flame resistant insulated wire - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flame-retardant insulated wire, and particularly to a flame-retardant insulated wire suitable for preventing the generation of rogen gas during combustion.

Ethylene propylene copolymers and polyethylene-based polymers, which have excellent electrical insulation properties, are often used as insulating materials for electric wires and cables.

However, as a recent trend, there has been a strong demand for flame retardancy for electric wires and cables used in nuclear power plants, as well as electric wires for wiring inside panels and machines. As a method to make polymer flame retardant,
...Methods of mixing halogen-containing compounds, su7-containing compounds, etc. have been used, but these are considered problematic because they emit a large amount of smoke in the event of a fire, and they also generate halogen gas, which is harmful to the human body. .

In light of this situation, hydrated alumina, which produces very little smoke and does not emit harmful gases, has recently been attracting attention. However, 7. In order to impart flame retardancy,
When only hydrated alumina is added, it is necessary to add a large amount of hydrated alumina, which results in the problem of deterioration of electrical properties, and in particular, the problem of a decrease in insulation resistance due to water absorption and moisture absorption. .

The present invention (d) has been made in view of the above, and its purpose is to have a flame-retardant insulated wire that has good electrical characteristics and flame retardancy, and does not generate harmful halogen gas when burned. Our goal is to provide the following.

The feature of the present invention is that a flame-retardant electric material is produced by crosslinking a mixture of 100 parts by weight of ethylene polymer, 100 parts by weight or more of water-containing alumina, and 01 parts by weight of 2-mercaptobenzimidazole. The main feature is that the flame-retardant insulated wire is coated with an insulating material.

Here, the ethylene polymer refers to ethylene propylene copolymer, ethylene propylene diene turbo polymer, polyethylene, ethylene vinyl acetate copolymer, ethylene ethyl acrylate copolymer, ethylene copolymer, etc. alone or in combination.

The reason why the amount of hydrated alumina is limited to 100 parts by weight or more is because flame retardancy (JTS horizontal) becomes insufficient below the limited value.

The reason why the amount of 2-mercaptobenzimidazole added is limited to 0.1 parts by weight or more is that if it is less than the limited value, the desired suppression of the deterioration of electrical characteristics cannot be achieved. The electrical properties of water-use alumina deteriorate due to water absorption and moisture absorption because the hydroxyl groups on the surface of water-use alumina adsorb a large amount of water.In order to suppress this, 2-methylcaptobenzimidazole is added. I made it.

Suitable crosslinking agents include organic peroxides such as dicumyl peroxide and 1°5-bis(t-butylperoxy/isopropyl)benzene, which may be used alone or as an auxiliary agent in combination with sulfur, ethylene dimethacrylate, Diacrylphthalate, p-quinonedioquine, etc. may be used in combination.

As antioxidants, in addition to using the above-mentioned 2-mercaptobenzimidazole alone, amine-based antioxidants such as phenyl-α-naphthylamine, N,N'-di-β-naphthyl-p-phenylenediamine, and 2,6 It can also be used in combination with phenolic antioxidants such as -di-t-butyl-4-methylphenol and hindered phenol.

It goes without saying that in addition to this, a lubricant, softener, dispersant, etc. may be added as necessary.

Next, examples and comparative examples of the present invention will be described. Table 1 shows the compositions of Examples and Comparative Examples of flame-retardant electrical insulators used as coatings for flame-retardant insulated wires of the present invention.

The electric wire is manufactured by kneading each compound shown in Table 1 with a roll, and then kneading it at 40% by keeping the renoder temperature at 120°C.
Using an extruder (L/rJ-25), a copper wire with an outer diameter of 20 mm was coated with a thickness of 1 mN, and then cross-linked by applying 13 atm steam (approximately 195°C) for 6 minutes. .

Table 1: Units are parts by weight Next, the insulation resistance and flame retardance (JIS horizontal) were examined using each of the electric wires manufactured as described above as samples. The results are shown in Table 2. However, the insulation resistance was measured at 80℃ after crosslinking.
After drying for 24 hours at a humidity of 93 and a temperature of 20℃, measurements were taken before and after being left for one month, and the measurement method was JISO30.
I also went there on 04. In terms of flame retardancy evaluation, if the burner extinguished the flame within one minute, the flame retardancy was evaluated as passing, and if it burned for more than one minute, it was evaluated as failing.

Table 2 According to Table 2, all of the wires coated with the flame-retardant electrical insulators shown in Examples 1 to 5 according to the present invention showed no decrease in insulation resistance even when left at 93% humidity for one month. It is small and has passed JIS level flame retardancy.

On the other hand, in Comparative Example 1, the amount of hydrated alumina was less than the limit value, so the flame retardance was rejected. Further, in Comparative Example 2, since the amount of 2-mercaptobenzimidazole added was below the limit value, the insulation resistance significantly decreased when left in an atmosphere with a humidity of 93% for one month.

As mentioned above, according to the embodiments of the present invention, good frost,
It has flame-retardant properties such as air-bacterial properties, and since it is not mixed with halogen-containing compounds or phosphorous-containing compounds, it does not generate harmful rogens gas when burned, making it suitable for use as electric wires and cables for nuclear power plants. and has great industrial value.

Note that the same effect can be obtained by using an inorganic-containing compound such as magnenium hydroxide, magnenium carbonate, or zinc borate instead of hydrated alumina. In fact, similar effects can be obtained by using 2-mercaptobenzimidazole (the-mercaptomethylbenzimidazole) or any of these compounds.

As explained above, according to the present invention, there is an effect that it has good electrical characteristics and combustibility, and does not generate harmful halogen gas or the like during combustion.

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Claims (1)

[Claims] 1. Flame-retardant electrical insulation made by crosslinking a mixture of 1,100 parts by weight of ethylene-based poly, 100 parts by weight of hydrated alumina, and 1 part by weight or more of 2-methylcaptobenzimidazole. A flame-retardant insulated wire characterized by being coated with an object.