JPS5887709A - 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 provides flame retardant insulation type Ivi! (including cables), and particularly relates to flame-retardant insulated wires that do not generate halogen 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, but recently there has been a trend toward using them for electric wires and cables for nuclear power plants, and for wiring inside panels and machines. There has been a strong demand for electric wires to be flame retardant. Conventionally, the method of making polymers flame retardant has been to mix halogen-containing compounds, phosphorus-containing compounds, etc., but these can generate chlorine gas, which is harmful to the human body in the event of a fire, or produce large amounts of It generates smoke and is considered a problem.

In view of this situation, water-use alumina, which emits very little smoke and does not emit harmful gases, has recently been attracting attention. However, in order to impart flame retardancy, it is necessary to add a large amount of water-use alumina if only the water-use alumina is added, which results in the problem of deterioration of electrical properties, especially the insulation caused by water absorption and moisture absorption. The decrease in resistance has become a very big problem.

An object of the present invention is to eliminate the drawbacks of the prior art described above, and to provide a flame-retardant insulated wire that has good electrical properties and flame retardancy, and does not generate harmful gases such as halogen when burned. It's about doing.

The present invention was made based on the fact that the deterioration of electrical properties due to water absorption and moisture absorption of hydrated alumina is due to the fact that the hydroxyl groups on the surface of hydrated alumina adsorb a large amount of water. A flame-retardant electrical insulator obtained by crosslinking a mixture of 60 to 100 parts by weight of water-use alumina and further added tar or clay such that the total filling amount including the water-use alumina is 1604 parts by weight or more. It is characterized by a flame-retardant insulated wire coated with

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

The amount of hydrated alumina was limited to 60 to 100 parts by weight because below the limit value, the flame retardance (JIS horizontal) is insufficient, and above the limit value, a significant decrease in insulation resistance will occur. .

The reason why the fillers used in combination with hydrated alumina are limited to talc and clay is that fillers other than these cause problems such as deterioration of processability, mechanical properties, electrical properties, etc.

The total loading of hydrated alumina and talc or clay is 16
The reason why the amount is limited to 0 parts by weight or more is because the desired flame retardance cannot be imparted if the amount is less than the limited value. Although no upper limit was specified, it is preferably 600 parts by weight or less since processability, mechanical properties, and electrical properties deteriorate.

Suitable crosslinking agents include organic peroxides such as dicumyl peroxide and 1゜3-bis(t-butylperoxyisoglobil)benzene, which can be used alone or as an auxiliary agent with sulfur or ethylene dichloromethane. Methacrylate, diacrylphthalate, P-quinone dioxime, etc. may be used in combination.

As antioxidants, phenyl-α-naphthylamine,
N, amines such as 1/-di-β-naphthyl-P-phenylenediamine and 2,6-di-t-butyl-4
- Phenolic antioxidants such as methylphenol and hindered phenol.

It goes without saying that other than these, lubricants, softeners, dispersants, etc. may be added as necessary.

Next, Examples and Comparative Examples of flame-retardant electric insulators that are coating materials for flame-retardant insulated wires of the present invention will be described. Table 1 shows the compositions of Examples and Comparative Examples of flame-retardant electric insulators, with Examples 1 to 505 and Comparative Examples 6 and 7. Note that the unit of blending amount is parts by weight.

In the production of company lines, each compound is mixed and kneaded with a roll, and then the mixture is rolled into a 40m/
m extruder (L/D=251, outer diameter 2, 0 fl
Coated copper wire with 11O+ thickness and heated with 13 atm steam (
A test sample was produced by crosslinking by applying a temperature of about 195° C. for 3 minutes.

Table 1 Next, the test results will be explained.

In the test, insulation resistance and flame retardance were measured using the electric wire manufactured as described above as a sample. The insulation resistance was measured by drying each sample after crosslinking at 80°C for 24 hours, and then leaving it in an atmosphere with a humidity of 96%.The measurement method was J Engineering SC300.
In the flame retardancy evaluation conducted based on No. 4, a flame retardant was evaluated as passing if it disappeared within 1 minute when burned with a burner, and a failure was evaluated if it burned for more than 1 minute. Table 2 shows the results.

Table 2 Note: After being left in an atmosphere with a humidity of 93% (20°C),
, after being left alone for one month.

According to Table 2, all of the samples using the flame-retardant electrical insulators of Examples 1 to 5 according to the present invention showed a small decrease in insulation resistance even when left in an atmosphere with a humidity of 96%. The flame retardance has passed JIS level. On the other hand, in Comparative Example 6, the amount of water-containing alumina is as large as 150 parts by weight, so when it is left in an atmosphere with a humidity of 93%, the insulation resistance decreases significantly.

In addition, in Comparative Example 7, the total amount of irrigated alumina and talc was as small as 80 parts by weight, so the flame retardance was rejected. As described above, according to the embodiments of the present invention, the decrease in insulation resistance is small and the flame retardance is good because water adsorption is suppressed and heat conduction and heat radiation during combustion are interrupted. It is.

Furthermore, no harmful gases such as halogens are emitted during combustion.

Note that the same effect can be obtained by using an inorganic hydrated compound such as magnesium hydroxide, magnesium carbonate, or zinc borate instead of water-use alumina.

As explained above, the present invention has good electrical characteristics and flame retardancy, and does not generate harmful gases such as halogens during combustion, and is suitable for use in nuclear power plants and is suitable for industrial use. This has the effect of being of great value.

Claims (1)

[Claims] 1. Hydrated alumina 6 in 100 parts by weight of ethylene polymer
0 to 100 parts by weight, and further added talc or clay such that the total filling amount including the water-use alumina is 130 parts by weight or more. A flame-retardant insulated wire characterized by: