JPS6212005A - Flame resisting electric insulator compositioin - 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] [Industrial Field of Application] The present invention is directed to a flame-retardant electrical insulating composition that does not generate toxic halogen-based scum when burned, particularly for application to insulating materials and sheath materials for electric wires and cables. The present invention relates to a suitable flame-retardant resin composition.

[Prior Art V#r] Ethylene propylene copolymers and ethylene α-olefin copolymers with polyethylene, which have excellent electrical insulation properties, are often used as insulating materials and sheath materials for electric wires and cables.

As a recent trend, there has been a strong demand for a high degree of flame retardancy for electric wires and cables used in nuclear power plants, vehicles, and the like.

As a method of making an ethylene α-olefin copolymer flame retardant, a method of mixing a halogen-containing compound and antimony trioxide has generally been adopted.

However, these are viewed as problematic because they generate a large amount of smoke when burned and also generate gases that are harmful to the human body.

In light of this situation, attention has been focused on a method of mixing metal hydroxides with hydrated alumina and magnesium hydroxide, which generate very little smoke and do not generate toxic residue.

[Problems to be solved by the invention] However, in order to impart a high degree of flame retardancy, it is necessary to add a large amount of metal hydroxide, which results in a significant decrease in mechanical properties such as tensile properties. There is.

The present invention has been made based on the above, and aims to provide a flame-retardant electrical insulating composition that can provide a high degree of flame retardancy, has excellent tensile properties, and does not emit toxic halogen gases. This is the purpose.

[Means for Solving the Problems] The flame-retardant electrical insulation composition of the present invention is a blend of an ethylene α-olefin copolymer and an ethylene vinyl acetate copolymer or an ethylene alkyl acrylate copolymer.
It is characterized by containing 20 parts by weight or more of a metal hydroxide and 1 part by weight or more of a phosphorous flame retardant with respect to weight B (≦).

In the present invention, examples of the ethylene α-olefin copolymer include ethylene propylene copolymer, ethylene propylene terpolymer, ethylene butene copolymer, ethylene butene terpolymer, and polyethylene,
These can be used alone or in combination of two or more.

The ethylene vinyl acetate copolymer or ethylene alkyl acrylate copolymer blended with the ethylene alpha-olefin copolymer includes ethylene vinyl acetate copolymer,
Examples include ethylene methyl acrylate copolymer, ethylene ethyl acrylate copolymer, and ethylene butyl acrylate copolymer.

The appropriate blend weight ratio of ethylene α-olefin copolymer/ethylene vinyl acetate copolymer or ethylene alkyl acrylate copolymer is 95 to 2015 to 80,
It can vary depending on the properties of the blend.

Examples of metal hydroxides include aluminum hydroxide, magnesium hydroxide, basic magnesium carbonate, and hydrotalcites.

By using these materials whose surfaces have been treated with a silane coupling agent, a titanate coupling agent, a fatty acid metal salt, etc., the extrusion processability of the composition can be improved.

The amount of metal hydroxide is 20 parts by weight per 100 parts by weight of the blend.
It is necessary to mix more than 1 part by weight, and if it is less than this, the desired flame retardance cannot be imparted.

Phosphorous flame retardants improve flame retardancy through dehydration and carbonization during combustion, and include red phosphorus, ammonium polyphosphate, and polyphosphoric acid amide.

These can be surface-treated with phenolic resins, silane coupling agents, titanate coupling agents, and fatty acid metal salts to improve their dispersibility and compatibility in blend polymers.

1 part of phosphorus flame retardant per 100ffi of the blend
It is necessary to mix at least part by weight, and if it is less than this, sufficient flame retardance cannot be imparted.

In the present invention, in addition to the above components, crosslinking agents, antioxidants, lubricants, softeners, dispersants, etc. may be added as appropriate.

As a crosslinking agent, dicumyl peroxide, 3-bis(
Organic peroxides represented by t-butylperoxyisopropyl)benzene are suitable, and sulfur, ethylene dimethacrylate, diacrylphthalate, p-quinone dioxime, etc. may be used in combination with this as a crosslinking aid. .

Further, in the case of crosslinking using 9 electron beams, a reactive monomer such as trimethylolpropane trimellitate or triallyl isocyanurate is generally added as a crosslinking aid.

As antioxidants, phenyl-α-naphthylamine,
~ N J-di-β-naphthyl-p-phenylenediamine and other amine antioxidants, 2,6-di-t-butyl-
Examples include phenolic antioxidants such as 4-methylphenol and hindered phenol.

[Example] Various ingredients were mixed into 100% according to the blending ratios shown in Table 1.
The mixture was put into a 6-inch roll kept at 120°C for roll kneading, and after kneading it was kept at 120°C at 40 m/m
Using an extrusion machine (L/D=25), extrusion coating was applied to a copper wire with an outer diameter of 1.25 mm to a thickness of 0.8 mm, and then 13 kg
/cm' water vapor atmosphere for 3 minutes to form a cross-linked insulation T.
'ti line was prepared.

The evaluation results on each side are shown in the lower column of Table 1.

The evaluation was performed as follows.

Flame retardancy: Conducted based on J15C3004, if it disappears within 1 minute, it passes; if it burns for more than 1 minute, it passes.

Tensile properties: After cross-linking, the copper wire was pulled out and left in a constant temperature room at 20°C for one day, then tested at a tensile rate of 5 using a Schotsuba tensile tester.
00 mm/min.

As is clear from Table 1, Examples 1 to 1 according to the present invention
6, the tensile properties satisfy the electrical appliance standards (cabbtire cable and outlet v; A0, 7 kg/mtn' or more), and the flame retardance also passes J 1sc3004.

On the other hand, in Comparative Example 1 in which the ethylene α-olefin copolymer was used alone, the tensile properties did not satisfy the electrical appliance standards. Moreover, in Comparative Examples 2 to 4 in which the amount of metal hydroxide or phosphorus flame retardant added is less than the specified value, the flame retardance is insufficient.

[Effects of the Invention] As explained above, the present invention provides a blend of an ethylene α-olefin copolymer and an ethylene vinyl acetate copolymer or an ethylene alkyl acrylate copolymer,
Contains metal hydroxide and phosphorus flame retardant,
It becomes possible to obtain a molded article that has a high degree of flame retardancy while maintaining good tensile properties, and does not generate toxic halogen scum when burned.

Claims (2)

[Claims] (1) 20 parts by weight or more of a metal hydroxide and 1 part of a phosphorus flame retardant to 100 parts by weight of a blend of an ethylene α-olefin copolymer and an ethylene vinyl acetate copolymer or an ethylene alkyl acrylate copolymer. 1. A flame-retardant electrical insulating composition containing at least part by weight. (2) The blend weight ratio of ethylene α-olefin copolymer/ethylene vinyl acetate copolymer or ethylene alkyl acrylate copolymer in the blend is 95 to 20
The flame-retardant electrical insulating composition according to claim 1, which has a molecular weight of /5 to 80.