JPS6134038A - Flame-retarding electrical insulating composition - Google Patents

Abstract

PURPOSE:The titled composition which has excellent tensile properties and flame retardancy, does not evolve halogen gases when burnt, and is suitable as a sheath material for wires, cables, etc., containing a specified acrylate copolymers and an inorganic flame retardant. CONSTITUTION:100pts.wt. acrylic copolymer (crystalline m.p. peak temperature as determined by differential calorimetry >=85 deg.C) of formula I [wherein R is an ester group of formula II (wherein R' is a 1-8C alkyl) and m and n are natural numbers] is mixed with 50-200pts.wt. Al- or Mg-containing inorganic flame retardant (e.g., aluminum hydroxide or basic magnesium carbonate). As said acrylate copolymer, an ethylene/methyl acrylate copolymer or the like is used. It is also possible to add a filler (e.g., talc), an antioxidant (e.g., phenyl-alpha-naphthylamine), a lubricant, etc., in addition to said inorganic flame retardant.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a gas insulating composite oxide that does not generate halogen gas when burned.

[Conventional technology]

A recent trend is that electrical cables used in ships, buildings, etc. are required to have a high degree of flame retardancy.

Conventionally, vinyl has been widely used as a flame-retardant electrical insulating material, but it has been viewed as problematic because it contains norogen elements and produces a large amount of smoke in the event of a fire, as well as emitting gases that are harmful to the human body. .

In light of this situation, a method of mixing an inorganic flame retardant with very little smoke generation and toxicity into a polyolefin that does not contain logen elements has been attracting attention.

[Problem that the invention seeks to solve]

However, although it is necessary to add a large amount of inorganic flame retardant to impart a high degree of flame retardancy, when it is added to polyethylene or ethylene propylene rubber, it causes a significant decrease in tensile properties. When added to ethylene vinyl acetate copolymer, it is very difficult to imitate. - The present invention has been made based on the above, and it is possible to obtain a molded product that has good tensile properties, a high degree of flame retardancy, and does not generate toxic halogen gas when burned. The object of the present invention is to provide a flammable electrical insulation composition.

[Failure to solve the problem]

The flame retardant composition of the present invention has the general formula: number 1 to 8 alkyl group).

A1. It is characterized by containing 50 to 200 parts by weight of an inorganic flame retardant containing atoms or Mg atoms.

[Effect]

In the present invention, examples of the acrylate copolymer represented by the above general formula include ethylene methyl acrylate copolymer, ethylene ethyl acrylate copolymer, ethylene butyl acrylate copolymer, and ethylene hexyl acrylate copolymer, which may be used alone or in combination of two or more. Can be used together.

Further, these may be used in combination with ethylene polymers such as polyethylene, polyethylene, ethylene propyrolyte/rubber, etc.

Such an acrylate copolymer must have a crystal melting point peak temperature of 85°C or higher according to DSC;
Below this, the softening point decreases and the heat deformation resistance significantly decreases.

Examples of inorganic flame retardants containing A1 atoms or Mg atoms include aluminum hydroxide, basic magnesium carbonate/rum, magnesium hydroxide, basic magnesium aluminum hydroxy carbonate hydrate (hydrotalcite), etc. can be given.

Such an inorganic flame retardant must be blended in an amount of 50 to 20 parts by weight per 100 parts by weight of the acrylate polymer; if it is less than 50 parts by weight, it will not be possible to impart the desired flame retardancy; If it is exceeded, mechanical properties such as tensile properties will deteriorate.

In the present invention, inorganic flame retardants and fillers such as talc, clay, and calcium carbonate may be used together, and in addition to the above components, antioxidants, lubricants, softeners, dispersants, etc. may be added. .

As the antioxidant, amine antioxidants such as phenyl-α-naphthylamine, N-N'-di-β-naphthyl-p-phenylenediamine, N-isopropyl-N'-phenyl-p-phenylenediamine, 2,6-G-t-
Butyl-4-methylphenol, hindered phenol, 6-(4-hydroxy-3,5-di-tert-butyl anilino)-2゜4-bis-octyl-thio-1,3,5
-triazine, 4,41-methylene-bis-(2,6-
Examples include phenolic antioxidants such as di-tert-butylphenol.

By extrusion coating the outer periphery of at least one insulated wire core, it is possible to obtain an electrical cable with a high degree of flame retardancy.

〔Example〕

120 with various ingredients in the proportions shown in Table 1.
The mixture was put into a 6-inch roll kept at 120°C and kneaded with rolls.
m extruder (L/D=25), outer diameter 5.0 mm
A cable was produced by wrapping a copper tape around the outer periphery of three twisted cross-linked polyethylene insulated wire cores, and extrusion coating the tape to a thickness of 1.3 mm. The evaluation results of the cable thus produced are as shown in the lower column of Table 1.

Tensile properties were determined by taking five test pieces from the cable using a dumbbell No.
Measured at 00mm/min.

Heat deformation resistance was determined by cutting a test piece with a length of 4 an.
ρ, ρQAI/l/IQ'74t17m*[la"l$
The heat deformation rate was measured after 4 hours under a 90'C1 load of 500 g, and those with a heat deformation rate of 50% or less were judged to have passed, and those with a heat deformation rate of 50% or less were judged to be rejected.

For flame retardancy evaluation, eight cables are lined up vertically and a 70,000 BTU flame is applied from below for 20 minutes, and if the flame self-extinguishes, it passes; if it burns out without self-extinguishing, it fails.

As is clear from Table 1, Examples 1 to 1 according to the present invention
The material shown in 6 shows tensile properties that meet the vinyl standards and polyethylene standards stipulated in the Electrical Appliance and Materials Control Law.
It also has excellent heat deformation resistance and passes the vertical tray combustion test.

On the other hand, Comparative Example 1, in which the amount of inorganic flame retardant added was small, failed in flame retardancy, and Comparative Example 2, in which the amount added exceeded 200 parts by weight, had poor tensile properties. Furthermore, Comparative Example 3 using an acrylate copolymer having a crystal melting point peak temperature of 85° C. or less by DSC was rejected in terms of carbon thermal deformability.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to obtain a molded article that has excellent tensile properties, heat deformation resistance, and flame retardancy, and does not generate toxic halogen gas when burned.

Procedural amendment (5L) 59, 12.24 Showa year month day

Claims (1)

[Claims] (1) General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ Here, m and n are natural numbers, and R is an ester group represented by ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (R is a carbon number of 1 to 8 alkyl group). Contains 50 to 200 parts by weight of an inorganic flame retardant containing A1 atoms or Mg atoms per 100 parts by weight of an acrylate copolymer represented by A flame-retardant electrical insulating composition characterized by: