JPS5851414A - flame retardant 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 coated with a flame-retardant insulating material suitable for preventing the generation of halogen gas during combustion. It is.

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 high flame retardancy of UL standard VW-Lebel for electric wires and cables for nuclear power plants and electric wires for vehicles. The methods used to make such polymers flame retardant include mixing halogen-containing compounds, antimony trioxide, phosphorus-containing compounds, etc., but these produce a large amount of smoke in the event of a fire.
Additionally, there are problems such as the generation of gases that are harmful to the human body.

In light of this situation, hydrated alumina, which has very low smoke generation and does not emit harmful gases, has been attracting attention. However, when ordinary hydrated alumina is used, In order to provide a high degree of flame retardancy, it is necessary to add a large amount of water-containing alumina, which results in a problem of deterioration of electrical properties.In particular, deterioration of electrical properties due to water absorption and moisture absorption is a major problem. It becomes. 1 The present invention was made in view of the above, and its purpose is to provide a flame-retardant insulation that has good electrical characteristics and a high degree of flame retardancy, and does not generate harmful halogen gas when burned. The purpose is to provide electric wires.

A feature of the present invention is that a conductor is coated with a mixture of 100 parts by weight of ethylene polymer and at least 150 parts by weight of hydrated alumina having a conductivity index of 100 μΦ or less, and then cross-linked to produce an insulated wire.

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

Hydrated alumina is manufactured using bauxite and sodium hydroxide, but when we investigated the cause of the deterioration of electrical properties due to water absorption, we found that the main cause was water-soluble sodium oxide. It was found that the characteristics could be improved. The conductivity index is the electrical representation of this sodium oxide silkworm, and the conductivity index is 202 ml of hydrated alumina and 100 rn1. It is expressed by the conductivity at 20° C. when placed in water, and the higher the value, the higher the amount of sodium oxide. The conductivity index of hydrated alumina was limited to 100 pTJ/an or less.
This is because if the thickness exceeds 7/m, the electrical characteristics will deteriorate due to water absorption and moisture absorption.

The reason why the amount of water-use alumina was limited to 150 parts by weight or more was because
This is because if the amount is less than 150 parts by weight, the desired flame retardance cannot be imparted.

As a crosslinking agent, dicumyl oxide, 1°3-
Organic peroxides represented by bis(t-butylperoxyisopropyl)benzene are suitable, and they can be used alone or as an auxiliary agent to react with sulfur, ethylene dimethacrylate,
Diaryl phthalate, P-quinone dioxime, etc. may be used in combination.

Note that it is necessary to add an antioxidant, and examples of the antioxidant include phenyl-α-naphthylamine, N, W-
Examples include amine type antioxidants such as di-β-naphthyl-quenivine diamine, and phenolic type antioxidants such as 2,6-di-1-butyl-4-methylphenol and hindered phenol. It goes without saying that in addition to these, lubricants, softeners, dispersants, etc. may be added as necessary.

Next, examples and comparative examples of the present invention will be described.

Table 1 shows the compositions and amounts of flame-retardant insulating materials in Examples and Comparative Examples, and the amounts are expressed in parts by weight.

The electric wire is manufactured by kneading the mixture with rolls and then using a 40 m/m extruder (L/D=
25) with an outer diameter of 2. After coating the Ottan copper wire, it was crosslinked by applying 13 atmospheres of steam (temperature: about 195° C.) for 3 minutes.

Table 2 shows the test results for insulation resistance and flame retardancy among the electrical properties of insulated wires coated with the insulating materials of the Examples and Comparative Examples shown in Table 1.

Table 1 Insulation resistance was measured by drying at 80° C. for 24 hours after crosslinking and then leaving it in an atmosphere with a humidity of 93° C.

The measurement method was based on Tl5C3004.

In terms of flammability evaluation, if the flame disappears within 1 minute when burned with a burner, it passes the UL standard VW-1, and if it burns for more than 1 minute, it fails.

Table 2 *marks indicate after being left in an atmosphere with a humidity of 93% for one month As shown in Table 2, the insulation resistance of Examples 1 to 6 according to the present invention remained unchanged even when left in an atmosphere with a humidity of 93%. The deterioration is small, and the flame retardance passes UL standard VW-1. On the other hand, the material coated with the insulating material of Comparative Example 7 containing 100 parts by weight of hydrated alumina below the limited range of the present invention failed in terms of flame retardancy. Also, the conductivity index is 1
In Comparative Example 8, in which 200 parts by weight of 60 μU/crn hydrated alumina was added, the insulation resistance significantly decreased when left in an atmosphere with a humidity of 93 degrees.

As described above, according to the embodiments of the present invention, an insulated wire with excellent electrical characteristics and a high degree of flame retardancy that passes the UL standard VW-1 can be obtained, and furthermore, it is possible to obtain an insulated wire that has excellent electrical characteristics and has a high degree of flame retardancy that passes the UL standard VW-1. It is suitable for electric wires and cables for nuclear power plants, and has extremely high industrial value.

In the above embodiment, lead oxide is added as the metal oxide, but zinc oxide may also be used and the same effect can be obtained.

As explained above, according to the present invention, there is an effect that it has good electrical characteristics and a high degree of flame retardancy, and does not generate halogen gas during combustion.

Claims (1)

[Claims] 1. A flame retardant material characterized by coating a conductor with a mixture of 100 parts by weight of ethylene polymer and adding at least 150 parts by weight of hydrated alumina with a conductivity index of 100 μm3/'on or less, and then crosslinking the mixture. Insulated wire.