JPH0616874A - Flame-retardant composition - Google Patents

Abstract

PURPOSE:To obtain a flame-retardant compsn. which contains no halogen, is excellent in flame retardance and also in mechanical properties, and can be used in electric wire and cable, their connections, and building constructions. CONSTITUTION:A flame retardant compsn. comprises 100 pts.wt. polyolefin, 30-200 pts.wt. inorg. flame retardant, 1-50 pts.wt. molybdenum compd., and 0.5-30 pts.wt. carbon black. Compounding specified amts. of the molybdenum compd. and carbon black together with such an amt. of the flame retardant enables the production of a nonhalogen flame-retardant compsn. excellent in flame retardance mechanical properties, and processibility without the necessity for adding an excessive amt. of the flame retardant.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-halogen flame-retardant composition containing no halogen element, which is used for electric wires and cables, their connecting parts, and also for building structures.

[0002]

2. Description of the Related Art Conventionally, polyolefins such as polyethylene, polypropylene, and ethylene-vinyl acetate copolymer have been widely used for electric wires, cables, and their connecting portions because of their excellent electric insulation properties. .

[0003]

However, since polyolefin alone is inferior in flame retardance to polyvinyl chloride (PVC), there is a problem that it lacks self-extinguishing property when exposed to fire. there were. Therefore, conventionally, a halogen-containing flame retardant or an inorganic flame retardant such as an inorganic hydrate is added to a polyolefin base material.

With halogen-containing flame retardants, although good self-extinguishing properties can be obtained by the action of halogenated gas generated during combustion, the halogenated gas is harmful to the human body and peripheral equipment. There was a problem such as corroding.

On the other hand, in the case of the above-mentioned inorganic flame retardant, there is no problem of toxicity and the good self-extinguishing property can be obtained by the endothermic action by dehydration that occurs at the time of combustion, but in order to obtain such flame retardant effect. Requires large additions. However, when a large amount of this inorganic flame retardant is added, for example, when about 300 parts by weight of the inorganic flame retardant is added to 100 parts by weight of the polyolefin which is the base resin, the mechanical properties and processability of the composition itself deteriorate. There is a problem that there is a limit to increase the amount of use,
No higher flame retardancy could be expected.

The present invention has been made in view of the above conventional circumstances, and by mixing a specific amount of a molybdenum flame retardant and carbon black together with an inorganic flame retardant,
An object of the present invention is to provide a flame-retardant composition excellent in not only flame retardancy but also mechanical properties and processability by controlling the compounding amount of the inorganic flame retardant to an appropriate level.

[0007]

MEANS FOR SOLVING THE PROBLEM AND ACTION THEREOF The present invention provides 100 parts by weight of polyolefin and 30 to 30 parts of inorganic flame retardant.
The flame-retardant composition comprises 200 parts by weight, 1 to 50 parts by weight of a molybdenum-based flame retardant, and 0.5 to 30 parts by weight of carbon black.

The polyolefin used in the present invention is
For example, polyethylene (PE), polypropylene (P
P), ethylene-ethyl acrylate copolymer (EE
A), ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl methacrylate copolymer (EMA), ethylene-propylene copolymer (EPR), ethylene-propylene-gen-terpolymer (EPDM), and the like, These can be used alone or in combination.

Examples of the inorganic flame retardant used in the present invention include hydrates such as aluminum hydroxide, magnesium hydroxide, calcium hydroxide and barium hydroxide which are metal aquatic products. And, the addition amount is the same as the above-mentioned conventional addition amount (3 parts with respect to 100 parts by weight of polyolefin).
Even if the amount is 30 to 200 parts by weight instead of the compounding amount of about 00 parts by weight), sufficient flame retardancy can be obtained because the flame retardant as described above is used in combination. However, if the addition amount is less than 30 parts by weight, the flame retardant effect is hardly obtained, and if it exceeds 200 parts by weight, mechanical properties and workability are deteriorated, which is not preferable.

The molybdenum-based flame retardant used in the present invention includes molybdenum trioxide (MoO ₃ ), ammonium dimolybdenum [(NH ₄ ) ₂ Mo ₂ O ₇ ], octamolybdenum ammonium [(NH ₄ ) ₄ Mo ₈ O ₂₆ ], Sodium molybdenum (Na ₂ MoO ₄ ), molybdenum calcium (CaMoO ₄ ), and the like, and an inorganic flame retardant whose surface is coated with molybdenum. Examples thereof include those obtained by treating the surface of the above-mentioned inorganic flame retardant such as aluminum hydroxide and magnesium hydroxide with a molybdenum compound. And, the addition amount is set to 1 to 50 parts by weight because the flame retardant effect is hardly obtained when the amount is less than 1 part by weight.
This is because the addition of more than parts by weight cannot be expected to provide a further flame retardant effect, and conversely increases the viscosity and deteriorates the workability, which is not preferable.

The carbon black used in the present invention exhibits a flame-retardant effect when used in combination with the above-mentioned molybdenum-based flame retardant, and the amount added is 0.5 to 30 parts by weight.
This is because if it is less than 0.5 parts by weight, almost no flame retardant effect is obtained, and if it exceeds 30 parts by weight, further flame retardant effect cannot be expected, and conversely the mechanical properties are deteriorated, which is not preferable. .

As described above, by mixing 100 parts by weight of the polyolefin, which is the base resin, with the inorganic flame retardant and the above-described amounts of the molybdenum flame retardant and carbon black, the compounding amount of the inorganic flame retardant can be adjusted appropriately. It is possible to obtain a flame-retardant composition having a high flame retardancy, for example, an oxygen index (O.I.) of 30 or more, and excellent mechanical properties and processability by suppressing the amount to a standard level.

In the composition of the present invention, in addition to the above materials, if necessary, other additives such as pigments,
An anti-aging agent, a processing aid, a stabilizer and the like may be added in appropriate amounts. Further, an appropriate amount of a cross-linking agent such as an organic peroxide (for example, DCP) or a cross-linking aid may be added for cross-linking.

[0014]

EXAMPLES Based on the formulations shown in Table 1, flame-retardant compositions according to the present invention (Examples 1 to 4) and compositions lacking the conditions of the present invention (Comparative Examples 1 to 7) were produced and The flammability (oxygen index), mechanical properties (tensile strength, elongation), and extrudability were tested. The results are also shown in the table.

[0015]

[Table 1]

From Table 1, in the case of the flame-retardant composition according to the present invention (Examples 1 to 6), high flame retardancy (oxygen index = 30) was obtained.
From the above, it can be seen that the mechanical properties and workability are excellent. In contrast, a composition lacking the conditions of the present invention (Comparative Example 1
~ 7), the desired flame retardancy may not be obtained,
It is also understood that there are problems such as poor mechanical properties and workability.

[0017]

As described above, according to the flame-retardant composition of the present invention, the molybdenum-based flame retardant and the carbon black are blended in a specific ratio together with the inorganic flame retardant such as a hydrate. It is possible to obtain a non-halogen flame-retardant composition which is excellent in mechanical properties and processability as well as having high flame retardancy, without excessively blending the flame retardant.

If this flame-retardant composition is used as a coating material for electric wires or cables, electric wires or cables with excellent characteristics can be obtained, and if it is used as a coating material for connecting portions of electric wires or cables, connection with excellent characteristics can be obtained. Part is obtained. Furthermore, this flame-retardant composition can be used for a building structure or the like that requires flame retardancy, and thereby an excellent flame-retardant effect is obtained in which no harmful gas is generated.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Izumi Ishikawa 1-5-1, Kiba, Koto-ku, Tokyo Inside Fujikura Electric Wire Co., Ltd.

Claims (1)

[Claims] 1. A flame-retardant composition comprising 100 parts by weight of a polyolefin, 30 to 200 parts by weight of an inorganic flame retardant, 1 to 50 parts by weight of a molybdenum-based flame retardant, and 0.5 to 30 parts by weight of carbon black. .