JPH0694522B2 - Flame retardant composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a flame-retardant composition used for electric wires, cables, etc., which does not generate harmful gas such as halogen.

<Prior Art> Recently, problems of fire spread of electric wires and cables, generation of harmful gas, and amount of smoke emitted have become problems, and various improvements have been proposed.

For example, as a proposal for preventing the spread of fire, JP-A-55-6967
JP-A-56-18636 discloses a composition using a flame-retardant composition obtained by adding hydrated alumina and phosphate frit to polychloroprene as seen in JP-A No. 9-90, and a flame-retardant composition which does not generate harmful gas. As can be seen in the publication, there are some which add a large amount of an inorganic water-containing compound to polyolefin.

<Problems to be solved by the invention> However, even in these proposals, prevention of spread of fire, elimination of generation of harmful gas, reduction of smoke generation, and further satisfaction of tapes, sheets, etc. as finished products Has not been obtained.

<Means and Actions for Solving Problems> The present invention is intended to solve the above problems, and the gist thereof is a non-halogen rubber / plastic, preferably an ethylene / propylene copolymer and a non-halogen rubber.・ Using a plastic blend as the base polymer,
This is a flame-retardant composition in which an inorganic water-containing compound, a halogen-free carbonization promoter, and a metal oxide or a silicon oxide are blended.
By installing it on the outermost layer of the cable,
You can get the cable.

Hereinafter, the details of the present invention will be described together with the operation.

First, the base polymer used in the present invention is an ethylene / propylene copolymer, butyl rubber, butadiene rubber,
SBR (styrene butadiene rubber), polyethylene, polypropylene, ethylene-α-olefin multi-component copolymer, ethylene-vinyl acetate copolymer, EEA (ethylene-
Ethyl acrylate), EAA (ethylene-acrylic acid), EMAA (ethylene-methacrylic acid copolymer),
Rubber and plastic that does not contain halogen elements such as ethylene acrylic elastomer. Then, in consideration of processability and the like, the ethylene / propylene copolymer is used as an essential component and the above-mentioned other rubber / plastic is blended therein. By blending in this way, it is possible to suppress the generation of harmful gases such as halogen gas and the amount of smoke generation, and also solve the problems in extrusion, molding into tapes, sheets and the like.

Then, in order to further improve the flame retardancy, with respect to 100 parts by weight of the base polymer, an inorganic water-containing compound,
Magnesium hydroxide, zinc borate, aluminum hydroxide,
50 to 200 parts by weight of basic magnesium carbonate or the like, and a carbonization promoter composed of a phosphate ester compound containing no halogen and / or a phosphate frit in order to more strongly prevent the heat carbonized layer from falling off. ˜50 parts by weight and 5 to 50 parts by weight of a metal oxide and / or silicon oxide forming a glass layer, preferably having a softening temperature of 500 ° C. or higher.

Examples of the phosphoric acid ester compound include TCP (tricresyl phosphate), TOP (trioctyl phosphate), O
DP (octyldiphenyl phosphate) and the like, and metal oxides include oxides of titanium, zirconium, antimony and the like. Further, a silicon oxide having a semi-metallic property similar to this metal oxide can also be used.

Incidentally, as a preferred structure, by blending the inorganic hydrous compound magnesium hydroxide and zinc borate in the range of 10: 1 to 50: 1, a stronger carbonized layer, it is possible to form a glass layer, or By subjecting the inorganic hydrous compound to a surface treatment with a titanium coupling agent, elongation after vulcanization of a sheet, tape or the like can be improved.

The reason for the above composition is that the inorganic hydrous compound is 200
If it is less than parts by weight, the flame retardant effect is not sufficient, and if it exceeds 400 parts by weight, the composition becomes too hard and the processability deteriorates. If it is less than 50 parts by weight, the carbonized layer is fragile, and if it exceeds 50 parts by weight, the flame retardancy is rather lowered. Further, if the amount of the metal compound or silicon oxide is less than 5 parts by weight, the burning time will be long, or the carbonized film will fall off when burning at high temperature, resulting in insufficient flame retardancy. This is because the product becomes too hard and the workability deteriorates.

Additives such as an antiaging agent, a coloring agent, a softening agent, a lubricant, and an ultraviolet absorber can be added to the flame-retardant composition of the present invention.

The composition of the present invention as described above is used by being extrusion-coated and molded into a sheet or tape.

The sheet-shaped or tape-shaped material is usually crosslinked (vulcanized) with a crosslinking agent (vulcanizing agent) and provided on the outermost layer of the electric wire / cable. Then, this waveform is wound while being overlapped, but in the case of this configuration, there are advantages that it can be easily applied and that replacement and the like are easy.

The thickness of this sheet and tape is about 0.5-1 mm,
Even if it is wound around 1/2 wrap twice, it is possible to achieve flame retardancy for electric wires and cables.

<Example> Example 1 The composition shown in Table 1 (Example No., Comparative Example No.
), The elongation characteristics and flame retardancy (short circuit, dropping of the refractory layer) and the like were examined.

As is clear from Table 1, the flame retardant composition of the present invention is
It can be seen that all the properties are excellent.

Example II A sample prepared by processing the No. 1 composition of Example I into a tape having a thickness of 1 mm and winding it twice around the outermost layer of a 6 KV, 1 × 150 mm ² CV cable with 1/2 wrap Then, the combustion test shown in FIG. 1 was performed. In this case, the two burners 2 and 2 are aimed at the sample wire / cable 1 from an angle of 120 degrees, and the core temperature of the burner flame is set.
The test was performed at 1020 ± 30 ° C for 10 hours.

The comparative example is the case where the composition of No. of the comparative example given in the above-mentioned Example 1 was processed into a tape shape and wound around the outermost layer of the CV cable. The results are shown in Table 2.

<Effects of the Invention> As described above, the flame-retardant composition of the present invention does not generate a harmful gas such as a halogen gas and has sufficient flame resistance (there is no loss of the refractory layer) and electrical characteristics (constant). No short circuit). In addition, it has sufficient elongation characteristics required for molding and is excellent in practical use.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a method of burning test of electric wire / cable. In the figure, 1 ... Sample (electric wire / cable), 2 ... Burner,

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Claims (2)

[Claims] 1. An ethylene / propylene copolymer and butyl rubber, butadiene rubber, SBR (styrene butadiene rubber), polyethylene, polypropylene, ethylene-α-
Contains a halogen element selected from olefin multi-component copolymer, ethylene-vinyl acetate copolymer, EEA (ethylene-ethyl acrylate), EAA (ethylene-click acid), EMAA (ethylene-methacrylic acid copolymer), ethylene acrylic elastomer Magnesium hydroxide, against 100 parts by weight of rubber / plastic mixture, not
200 to 400 parts by weight of an inorganic hydrous compound selected from zinc borate, aluminum hydroxide and basic magnesium carbonate, 5 to 50 parts by weight of a carbonization accelerator consisting of a halogen-free phosphate ester compound and / or a phosphate frit, titanium, zirconium A flame-retardant composition comprising 5 to 50 parts by weight of antimony metal oxide and / or silicon oxide. 2. The flame-retardant composition according to claim 1, wherein at least one of the inorganic hydrous compounds is surface-treated with a titanate coupling agent.