JPS6343205A - 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 flame retardancy to be imparted to electric wires and cables for vehicles and ships, and electric wires for wiring inside panels and aircraft.

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, but when ordinary aluminum hydroxide lamira is used, the electrical properties are deteriorated due to water absorption and moisture absorption. This results in the problem of significantly lowering the amount of water. In order to solve this problem, it is known to use aluminum hydroxide whose surface has been treated with a vinyl silane coupling agent or the like, but this is accompanied by a significant decrease in elongation, which poses a practical problem.

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

[Means for solving the problems] The flame-retardant electrical insulation composition of the present invention comprises polyolefin 10
It is characterized by containing 50 to 500 parts by weight of aluminum hydroxide surface-treated with phenylsilane relative to 0 parts by weight.

In the present invention, examples of the polyolefin include ethylene propylene copolymer, ethylene propylene dienter polymer, polyethylene, ethylene vinyl acetate copolymer, ethylene ethyl acrylate copolymer, ethylene butene copolymer, and ethylene butene dieter polymer, which may be used alone or in combination. It is possible to use more than one species in combination.

By using a material whose surface has been treated with phenylsilane, it is possible to suppress water absorption and moisture absorption, improve electrical properties, and suppress a decrease in elongation. The content of aluminum hydroxide surface-treated with phenylsilane must be in the range of 50 to 500 parts by weight per 100 parts by weight of the polyolefin; if it is less than 50 parts by weight, the desired flame retardance cannot be imparted; If it exceeds 500 parts by weight, 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-
Naphthylamine N.

Examples include amine antioxidants such as N-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 put into a 6-inch roll kept at 120°C and kneaded by rolls. After kneading, a 40m/m extruder (L/D-25) kept at 120°C was used to reduce the outer diameter to 2. Extrusion coating on Oa+m copper wire to a thickness of 1.0 cm, followed by 13 kg/cd
A crosslinked insulated wire was produced by holding the wire in a water vapor atmosphere for 3 minutes and 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: After cross-linking, the copper wire was pulled out, left in a constant temperature room at 20°C for one day, and then tested using a Schopper tensile tester at a tensile speed of 500 mm/m 1 ns for ethylene propylene copolymer and ethylene brobylene diene polymer systems, and 1 ns for other systems. Each measurement was made at 200 mm/min.

Insulation resistance: The wire was immersed in tap water at 75°C for 30 days, and then measured at a temperature of 20°C and a voltage of 500V.

As is clear from Table 1, Examples 1 to 1 according to the present invention
6, all passed the flame retardant test and were excellent in electrical properties and elongation. 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.

Furthermore, Comparative Example 3 using a non-specified run coupling agent had insufficient elongation, and Comparative Example 4 without surface treatment had low insulation resistance after immersion in water and poor extrudability.

[Effects of the Invention] As explained above, the present invention uses aluminum hydroxide surface-treated with phenylsilane as a flame retardant, and has a high degree of flame retardancy while maintaining good electrical properties and tensile properties. It is now possible to obtain electrical insulators that can be imparted with the following properties and that do not generate toxic halogen gases when burned.

Claims (1)

[Claims] (1) 50 to 500 parts of aluminum hydroxide surface-treated with phenylsilane to 100 parts by weight of polyolefin.
A flame-retardant electrical insulating composition characterized in that it contains parts by weight.