JPS6334805A - Flame resisting electrically insulating composition - Google Patents

Abstract

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

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a flame-retardant electrical insulation composition that does not generate toxic halogen gas when burned, and is particularly applicable to insulation materials and sheath materials for electric wires and cables. The present invention relates to a flame-retardant electrical insulation composition suitable for.

[Prior Art] Polyolefins, which have excellent electrical insulation properties, have been widely 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 for nuclear power plants, electric wires for vehicles, and electric wires for wiring inside panels and machines.

As a method of making polyolefin flame retardant, a method of mixing a halogen-containing compound, a phosphorus-containing compound, etc. has generally been adopted. However, these produce a large amount of smoke when burned, causing problems such as corrosivity to equipment and toxicity to the human body. In particular, recently there has been a demand for not generating such halogen-based gases from the standpoint of safety.

In light of this situation, inorganic flame retardants with extremely low smoke generation and toxicity are attracting attention. Among them, aluminum hydroxide is the most typical inorganic flame retardant.

[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 aluminum hydroxide, which results in a decrease in the tensile properties of the resulting insulator and sheath. There's a problem.

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

[Means for solving the problems] The flame-retardant electrical insulation composition of the present invention has polyolefin 10
It is characterized by containing 50 to 500 parts by weight of aluminum hydroxide with an average particle size of 0.2 μm or less per 0 parts by weight.

In the present invention, examples of the polyolefin include ethylene propylene copolymer, ethylene propylene genter polymer, polyethylene, ethylene vinyl acetate copolymer, ethylene ethyl acrylate copolymer, ethylene butene copolymer, and ethylene butene terpolymer, which may be used alone or in combination. A combination of the above is possible.

It is necessary to use aluminum hydroxide having an average particle size of 0.2 μm or less, and anything exceeding this is accompanied by a significant decrease in tensile properties. The lower limit is not particularly specified, but is 0.0
Generally, the thickness is 1 μm or more. The content of aluminum hydroxide must be in the range of 50 to 500 parts by weight based on 100 parts of polyolefin, and 50 parts by weight.
If it is less than 500 parts by weight, the desired flame retardancy cannot be imparted.
If the amount exceeds 1 part by weight, the processability will be significantly reduced and extrusion molding will become difficult.

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(t
-butylperoxyisopropyl)benzene is suitable, and as a crosslinking agent,
Sulfur, ethylene dimethacrylate, diallyl phthalate, p-quinone dioxime, etc. may be used in combination. Also,
In the case of crosslinking using ionizing radiation such as an electron beam, a reactive monomer such as trimethylolpropane trimellitate or triallyl isocyanurate is generally added as a crosslinking aid. As an antioxidant, phenyl-α-
Examples include amine antioxidants such as naphthylamine, NIN''-di-β-naphthyl-p-phenylenediamine, and phenolic antioxidants such as 2,6-di-t-butyl-4-methylphenol and hindered phenol. .

[Example] 100% of various ingredients were mixed according to the formulation shown in Table 1.
The mixture was placed in a 6-inch roll kept at 120°C, and the rolls were mixed.
L/D-25) was used to extrude coat a copper wire with an outer diameter of 2.0 mm to a thickness of 1.0[III+] to produce an insulated wire (Examples 5 and 6). For Examples 1 to 4 and Comparative Examples 1 to 3, crosslinked insulated wires were produced by extrusion coating and then holding in a steam atmosphere of 13 kg/cd for 3 minutes for crosslinking.

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

The evaluation was based on the following.

Flame retardancy: Based on JISC3004, if a wire held horizontally is burned in a burner and disappears within 1 minute, it is passed; if it burns for more than 1 minute, it is rejected.

Tensile properties: Pull out the copper wire from the wire, leave it in a constant temperature room at 20℃ for one day, and then use a Schopper type tensile tester at a tensile speed of 5.
Measured at 00 mm/mm.

As is clear from Table 1, Examples 1 to 1 according to the present invention
All of them passed the flame retardant test and had excellent tensile properties. On the other hand, in Comparative Example 1, in which the content of aluminum hydroxide was below the specified value, the flame retardance was rejected, and in Comparative Example 2, in which the content of aluminum hydroxide was above the specified value, extrudability was poor and molding was impossible. In addition, Comparative Example 3 in which the average particle size of aluminum hydroxide exceeds the specified value
The tensile properties are poor.

[Effects of the Invention] As explained above, the present invention uses aluminum hydroxide with an average particle size of 0.2 μm or less as a flame retardant, and has a high degree of flame retardancy while maintaining good tensile properties. It becomes possible to obtain electrical insulators that can be applied and do not generate toxic halogen gases when burned.

Claims (1)

[Claims] (1) Average particle size is 0 per 100 parts by weight of polyolefin
．． A flame-retardant electrical insulation composition containing 50 to 500 parts by weight of aluminum hydroxide having a diameter of 2 μm or less.