JPH0676524B2 - Flame-retardant composition and flame-retardant cable using the same - Google Patents

Description

The present invention relates to a so-called non-halogen flame-retardant composition containing no halogen element and a flame-retardant cable using the same.

<Prior Art> The conventional general flame-retardant method for cables includes (1). Resins containing halogen elements such as chlorine and bromine that are rich in flame retardancy, such as PVC, polychloroprene rubber, chlorosulfonated polyethylene rubber, chlorinated polyethylene, etc., or flame retardants such as antimony oxide for these resins. A method of further improving flame retardancy by adding,
(2). Flammable resin, eg polyethylene, ethylene-
A method of adding a flame retardant containing a halogen element such as chlorine or bromine in combination with antimony oxide to vinyl acetate copolymer (EVA), ethylene-ethyl acrylate (EEA), ethylene propylene (EP) rubber, etc. (3 ). There is a method in which aluminum hydroxide is used as a main flame retardant and a halogen element-containing flame retardant is not used.

<Problems to be Solved by the Invention> However, when the resin containing a halogen element and the flame retardant of the above (1) and (2) are used, for example, during combustion, hydrogen chloride (HCl), hydrogen bromide (HBr) A large amount of hydrogen halide gas such as is generated, and these gases corrode metals and give a harmful effect to the human body. Furthermore, a large amount of smoke is generated during combustion. Therefore, such a flame-retardant composition and a flame-retardant cable using this composition have safety problems, for example, in subways, underground malls, hospitals, general buildings, ships, nuclear power plants, It cannot be used in chemical plants or other facilities requiring high safety.

In this respect, when the aluminum hydroxide of (3) is used as a main flame retardant, no harmful gas or smoke is generated as in the above (1) and (2), but high flame retardancy is obtained. Since aluminum hydroxide must be highly filled, the mechanical properties and electrical properties of the flame-retardant composition itself or the sheath or insulator of a flame-retardant cable using the flame-retardant composition may deteriorate. In the case of extrusion molding, there is a problem such as foaming.

<Means for Solving Problems> The present invention has been made to solve the above-mentioned conventional problems, and its characteristic constitution is that 100 parts by weight of ethylene-α-olefin resin has an average particle diameter of 50 to 200 parts by weight of magnesium hydroxide of 0.3 μm to 2 μm and oil absorption of 0.5 ml / g to 2.
5 to 50 parts by weight of 0 ml / g carbon black powder, 3 to 10 parts by weight of organopolysiloxane, and a basic lead compound represented by xPbO.Pb (R) .yH ₂ O (where 0 ≦ x ≦ 3, R is Sulfuric acid group, higher fatty acid having 6 or more carbon atoms or aromatic carboxylic acid, and 0 ≦ y ≦ 10) 3 to 10 parts by weight of the mixture is added and mixed to form an organic peroxide vulcanizing agent. A flame-retardant composition crosslinked by, and a cable core in which the flame-retardant composition is provided with an insulator on a conductor, or a sheath in which a sheath is formed by twisting these into multiple cores with an intervening material. Or / and the flame-retardant cable used as the insulator. Then, if necessary, magnesium hydroxide is surface-treated with stearic acid or oleic acid, and a flame retardant containing red phosphorus is further added. In the case of a cable, inclusions between the twisted core and the sheath are removed. A flame-retardant composition containing no halogen element and having an oxygen index value of 30 or more can be obtained.

The flame-retardant cable of the present invention will be described in more detail with reference to FIGS. 1 and 2. In the figure, 1 is a conductor, 2 is an insulator, 3a and 3b are interposed, 4 is a sheath, 5 is a core tape, 6
Is a restraining tape.

Here, the sheath 4 is composed of 100 parts by weight of the flame-retardant composition of the present invention, that is, ethylene-α-olefin resin, 50-200 parts by weight of magnesium hydroxide having an average particle diameter of 0.3 μm-2 μm, and an oil absorption of 0.5. ml / g ~ 2.0 ml / g carbon black powder 5
To 50 parts by weight, organopolysiloxane 3 to 10 parts by weight, a basic lead compound represented by xPbO.Pb (R) .yH ₂ O containing no halogen element (where 0 ≦ x ≦ 3, R is a sulfate group, A higher fatty acid or aromatic carboxylic acid having 6 or more carbon atoms,
Further, it is formed of a flame-retardant admixture obtained by cross-linking an admixture obtained by adding and mixing 3 to 10 parts by weight (where 0 ≦ y ≦ 10) with a vulcanizing agent of an organic peroxide. The insulator 2 is the sheath 4
It is formed of the same flame-retardant composition as described above, or a usual rubber or plastic which does not contain a halogen element. First
Intervention 3a in the figure is a normal interposition formed of paper tape or jute, and intervening 3b in FIG. 2 is formed of a flame-retardant composition containing no halogen element and having an oxygen index value of 30 or more. It is a full-fledged intervention. In the case of this solid type intervention,
Preferably, in order to prevent fusion between the core and the sheath, as described above, the core tape 5 such as mylar is wound on the core and the restraining tape 6 is wound on the solid interposition.

<Function> The flame-retardant composition of the present invention and the flame-retardant cable using the same are composed of a base resin, which is a non-halogen ethylene-α-olefin resin containing no halogen element as described above, and a non-halogen additive. Therefore, even if you encounter a fire and burn, the combustion gas does not contain harmful gases such as halogenated element gas, which does not corrode the metal around the cable laying and has a harmful effect on the human body. It has no effect.

In addition, as magnesium hydroxide that causes an endothermic reaction upon release of water of crystallization, a specific particle size (0.3 μm to 2 μm) is added, so even if the filling is comparatively high, the mechanical properties deteriorate and the processability during extrusion is high. And the high filling rate provides extremely high flame retardancy. Particularly, in the case of magnesium hydroxide, the temperature of releasing water of crystallization is around 200 ° C. of aluminum hydroxide (this temperature is lower than the thermal decomposition of the resin depending on the resin and the temperature at which the resin used is limited). The temperature is higher than that of the base resin and is around 370 ° C., so that it is close to the thermal decomposition temperature of the base resin, and the kneading temperature and extrusion temperature of the resin used are hardly restricted. Furthermore, when magnesium hydroxide is surface-treated with stearic acid or oleic acid, a larger amount of filling can be achieved and good processability can be obtained. Also, as carbon black, a specific oil absorption (0.5ml / g ~ 2.0
(ml / g) is added, so the particle size is small and the surface area is large, so the flame-retardant effect is large, and sufficient flame-retardant effect can be obtained with a small amount of addition. Further, the carbon black in this composition is heated in a state where oxygen is blocked during combustion, and therefore carbonizes to form a carbonized layer in the composition. The formation of the carbonized layer effectively suppresses the flow of the composition itself and the outflow (melt drip) of the combustible material from the inside of the cable, so that the spread of fire is further prevented.

Organopolysiloxane (generally treated as silicone rubber) and xPbO / Pb with the above specific properties
Addition of the basic lead compound represented by (R) · yH ₂ O in combination improves flame retardancy. A small amount of these additives can provide a sufficient flame retardant effect.

When a specific amount of red phosphorus is added, the carbonization effect in the composition is further promoted during combustion. That is, in red phosphorus, when it is heated and oxidized at a high temperature, hydrogen is taken from the resin and dehydrated, so that carbonization of the resin is promoted. This dehydration and carbonization action can be achieved with a small amount of red phosphorus, and it is preferably used in combination with the above magnesium hydroxide.

Further, since the flame-retardant composition is cross-linked by the organic peroxide vulcanizing agent, it has excellent mechanical properties. Further, in making flame retardant, magnesium hydroxide having a specific particle size, carbon black having a specific oil absorption amount, and red phosphorus, which are good materials, are used. The amount of smoke is smaller than that of.

When a flame-retardant composition containing no halogen element and having an oxygen index value of 30 or more is used for the interposition as in the cable of FIG. 2, a sheath formed of the flame-retardant composition of the present invention is also used. Further, in combination with the structure with the insulator and / or the insulator, higher flame retardancy can be obtained.

As described above, as the base resin used in the present invention,
An ethylene-α-olefin resin, preferably an ethylene-α-olefin copolymer having 90% or more of an ethylene component having good mechanical properties such as high tensile strength can be mentioned.

The average particle diameter of the magnesium hydroxide of the present invention is 0.3μ
If it is less than 0.3 μm, the cohesive force is large, the dispersion in the mixture becomes poor, and the mechanical properties are adversely affected, and if it exceeds 2 μm, the adhesion with the resin is poor. This is because mechanical properties such as tensile strength and elongation are also deteriorated, which is not preferable. And, the addition amount is set to 50 to 200 parts by weight, if it is less than 50 parts by weight, a sufficient flame retardant effect cannot be obtained, and if it exceeds 200 parts by weight, there is too much and mechanical properties deteriorate. , Foaming during extrusion,
Furthermore, the workability is deteriorated.

The oil absorption of the carbon black of the present invention is 0.5 ml / g to 2.0.
The reason for using ml / g is to have a high flame retardant effect, good processability, and excellent mechanical properties.
This is because if it is less than g, the tensile strength is low and the flame retardant effect is small, and if it exceeds 2.0 ml / g, the viscosity of the admixture is high and processing failure occurs, and the electrical insulating property is deteriorated. And the added amount is 5 to 50 parts by weight is 5
If it is less than 50 parts by weight, the desired flame retarding effect and carbonized layer forming effect cannot be obtained, and if it exceeds 50 parts by weight, the viscosity of the admixture increases, the workability becomes poor, and the elongation decreases.

Examples of the organopolysiloxane used in the present invention include dimethylpolysiloxane, methylphenylpolysiloxane and methylvinylpolysiloxane. Further, a basic lead compound represented by xPbO.Pb (R) .yH ₂ O containing no halogen element of the present invention used in combination therewith (provided that 0 ≦ x ≦ 3, R is a sulfuric acid group, carbon number A higher fatty acid of 6 or more or an aromatic carboxylic acid, and 0 ≦
(y ≦ 10) or these surface-treated compounds include, for example, tribasic lead sulfate, dibasic lead phthalate, and basic lead stearate. And
The addition amount of each of these is set to 3 to 10 parts by weight. When the amount is less than 3 parts by weight, the flame retardancy-improving effect is hardly obtained, and the addition amount exceeds 10 parts by weight, and the total amount of both increases. If it is too much, the tensile strength will decrease, but the flame retardancy will not be improved despite the addition, and it will be expensive, which is not preferable in terms of cost.

Further, the amount of red phosphorus added in the present invention is set so that the red phosphorus component in the composition is 2 to 15 parts by weight. When the amount is less than 2 parts by weight, the effect of promoting the carbonization is hardly obtained, and This is because, if the amount is more than the amount by weight and the amount is too large, the flame retardancy is decreased, and the smoke generation is increased.

As the vulcanizing agent used in the present invention, in the case of a peroxide vulcanizing agent, for example, DCP (dicumyl peroxide), 2,5-dimethyl-2,5 di (t-butylperoxine) hexane, 2, Five
-Dimethyl-2,5-di (t-butylperoxy) hexine, t-butylperbenzoate and the like can be mentioned.

Then, in manufacturing the cable, the insulator and the sheath are extruded by a usual extrusion method. When interposing paper tape or jute, fill it vertically. In the case of solid inclusion, it depends on the extrusion method.

Although the illustrated cable is a multi-core cable, the present invention is of course applicable to a single-core cable.

(Example) Table 1 shows each example of the flame-retardant composition according to the present invention.
Is shown together with the respective characteristic test results. In addition, Table 2 shows compositions that do not meet the requirements of the present invention and ordinary polyvinyl chloride compositions as Comparative Examples 1 to 3 together with the results of their respective characteristic tests.

It can be seen from Table 1 above that each flame-retardant composition of the present invention satisfies the following performances and exhibits excellent properties when each compounding material is in a desired range.

Tensile strength, TS ≧ 1.0 Elongation El ≧ 350 * Performance standard of conventional cross-linked polyethylene (XLPE) (JIS C-
3605).

Mooney viscosity ≤35 Smoke emission ≤2.0 * ASTM A-1306.

Oxygen index value OI ≧ 25 * JIS D-2863.

On the other hand, according to Table 2, the following can be seen. In the comparative example, when the total amount of the organopolysiloxane and the basic lead compound is too large, the tensile strength decreases, but the flame retardancy does not increase so much. In the comparative example, a flame retardant containing bromine (decabromodiphenyl oxide) was used, and a large amount of hydrogen bromide gas was generated and a large amount of smoke was generated. The comparative example is a composition containing chlorine, which is well balanced in terms of OI and tensile strength, but is not preferable in terms of smoke generation and generation of hydrogen halide gas, corrosiveness, and toxicity.

Table 3 shows each example of the flame-retardant cable according to the present invention.
Is shown together with the respective characteristic test results. In addition, Table 4 shows the cables using the composition not satisfying the requirements of the present invention and the ordinary polyvinyl chloride composition, as Comparative Examples to, together with the respective characteristic test results.

From Table 3 above, each flame-retardant cable of the present invention is IE
You can see that you have passed EE Std. 383. That is, the finished appearance was good, there was no generation of hydrogen chloride gas, and there was little smoke emission, and a viewing distance of 100 m or more was obtained in each case. Further, it is understood that in order to obtain high flame retardancy, it is preferable to provide a solid flame retardant interposition.

On the other hand, from Table 4 above, the comparative example has a sheath flame-retarded with a flame retardant containing bromine, and although the combustion test passed, generation of hydrogen bromide gas is expected, and It emits a lot of smoke and has a short visibility distance. Comparative examples are all
Although the PVC sheath passed the combustion test, a large amount of hydrogen chloride gas was generated, which corroded the metal in the event of a fire and was harmful to the human body. There was also a large amount of smoke.

<Effects of the Invention> According to the present invention, as is clear from the above description, it has a high flame retardancy, and the combustion gas does not contain hydrogen halide gas and the like, which corrodes the surrounding metal. To provide a so-called clean flame-retardant composition and a flame-retardant cable that have never existed before, which do not have a harmful effect on the human body, emit a small amount of smoke, and have excellent mechanical properties. You can

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 and FIG. 2 are vertical cross-sectional views of a flame-retardant cable using the flame-retardant composition according to the present invention. 1 ... conductor, 2 ... insulator, 3a, 3b ... intervening, 4 ... sheath.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Hideo Sunazuka 1-5-1 Kiba, Koto-ku, Tokyo Fujikura Electric Wire Co., Ltd. (72) Akira Yoshino 1-1-5 Kiba, Koto-ku, Tokyo Fujikura Electric wire company (72) Inventor Takao Matsuda 1-5-1, Kiba, Koto-ku, Tokyo Fujikura Electric Line Co., Ltd. (72) Yoshiko Shingo 1-1-5, Kiba, Koto-ku, Tokyo Fujikura Den Line Co., Ltd.

Claims (3)

[Claims] 1. Magnesium hydroxide having an average particle size of 0.3 μm to 2 μm in 100 parts by weight of ethylene-α-olefin resin.
0 to 200 parts by weight, 5 to 50 parts by weight of carbon black powder having an oil absorption of 0.5 ml / g to 2.0 ml / g, and organopolysiloxane 3 to
10 parts by weight, a basic lead compound represented by xPbO · Pb (R) · yH ₂ O (provided that 0 ≦ x ≦ 3, R is a sulfuric acid group, a higher fatty acid having 6 or more carbon atoms or an aromatic carboxylic acid, Also 0 ≦ y
A flame-retardant composition, characterized in that an admixture obtained by adding and mixing 3 to 10 parts by weight (wherein ≦ 10) is crosslinked with a vulcanizing agent of an organic peroxide. 2. The flame-retardant composition according to claim 1, wherein magnesium hydroxide is surface-treated with stearic acid or oleic acid. 3. Magnesium hydroxide having an average particle size of 0.3 μm to 2 μm in 100 parts by weight of ethylene-α-olefin resin.
0 to 200 parts by weight, 5 to 50 parts by weight of carbon black powder having an oil absorption of 0.5 ml / g to 2.0 ml / g, and organopolysiloxane 3 to
10 parts by weight, a basic lead compound represented by xPbO · Pb (R) · yH ₂ O (provided that 0 ≦ x ≦ 3, R is a sulfuric acid group, a higher fatty acid having 6 or more carbon atoms or an aromatic carboxylic acid, Also 0 ≦ y
A flame-retardant composition obtained by cross-linking an admixture obtained by adding and mixing 3 to 10 parts by weight (wherein ≦ 10) with a vulcanizing agent of an organic peroxide, a cable core in which an insulator is provided on a conductor, or These are used as the sheath or / and the insulator of a cable in which a sheath is formed by twisting inclusions into multiple cores, and the inclusion provided between the cable core and the sheath does not contain a halogen element. Also, a flame-retardant cable comprising a flame-retardant composition having an oxygen index value of 30 or more.