JPS6147753A - Flame-retardant composition and flame-retardant cable using same - Google Patents

Abstract

PURPOSE:A flame-retardant composition, obtained by incorporating a rubber or plastic containing no halogen element with megnesium hydroxide, carbon black and organopolysiloxane, etc. and crosslinking the resultant mixture, having improved flame retardance and mechanical chareacteristics without containing toxic gases in the combustion gases. CONSTITUTION:A flame-retardant composition obtained by incorporating (A) 100pts.wt. rubber or plastic prepared by combination of one or more polyolefins with >=90% ehtylenic component without containing a halogen element with (B) 50-200pts.wt. magnesium hydroxide having 0.3-2mum average particle diameter, (C) 5-50pts.wt. carbon black powder having 0.5-2ml/g oil absorption, (D) 3-10pts.wt. organopolysiloxane and (E) 3-10pts.wt. basic lead compound expressed by the formula (0<=x<=3; R is sulfuric acid group, etc.; 0<=y<=10), and crosslinking the resltant mixture with a vulcanizing agent. The resultant composition is used as an insulator of cable cores and/or sheaths of cables.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) 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.

<Conventional technology> Conventional methods for making cables flame retardant include (1).

Methods using highly flame-retardant resins containing halogen elements such as chlorine and bromine, such as PVC, polychloroprene rubber, chlorosulfonated polyethylene rubber, and chlorinated polyethylene, or adding flame retardants such as antimony oxide to these resins. Method for further improving flame retardancy by adding (2)
), flame retardants containing halogen elements such as chlorine and bromine are added to flammable resins such as polyethylene, ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylate (EEA), and ethylene propylene (EP) rubber. There is a method in which it is added in combination with antimony oxide, a method (3) in which aluminum hydroxide is used as the main flame retardant, and a method in which a flame retardant containing a halogen element is not used.

<Problems to be Solved by the Invention> However, when the halogen element-containing resin and flame retardant of (1) and (2) above are used, for example, during combustion, hydrogen chloride (HCIl), hydrogen bromide (HBr) A large amount of hydrogen halide gases such as these are generated, and these gases corrode metals and have harmful effects on 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,
Due to safety issues, it cannot be used, for example, in subway stations, underground malls, hospitals, general buildings, ships, nuclear power plants, chemical plants, and other facilities where high safety is required.

In this regard, when aluminum hydroxide (3) is used as the main flame retardant, no harmful gas or smoke is generated as in (1) and (2) above, but if high flame retardance is to be obtained, , aluminum hydroxide must be highly filled, which may deteriorate the mechanical and electrical properties of the flame-retardant composition itself, or of the sheath and insulation of flame-retardant cables using it. When using extrusion molding, etc., there are problems such as foaming.

<Means for Solving the Problems> The present invention has been made to solve the above-mentioned conventional problems, and its characteristic structure is that 100 parts by weight of rubber or plastic that does not contain halogen elements is Particle size 0.
50 to 200 parts by weight of magnesium hydroxide with a diameter of 3 μm to 2 μm and an oil absorption of 0. 5 m j! / g~2.0m/!
/H carbon blank powder 5 to 50 parts by weight, organopolysiloxane 3 to 10 parts by weight, xPbO-Pb(R)
・Basic lead compound represented by yH20 (however, 0≦x≦
3, R is a sulfate group, a higher fatty acid having 6 or more carbon atoms, or an aromatic carboxylic acid, and O≦y≦10)3-1
A mixture obtained by adding and mixing 0 parts by weight of organic peroxide,
A flame-retardant composition cross-linked with a vulcanizing agent of sulfur or a sulfur-based compound, and a cable core in which an insulator is provided on a conductor, or a cable core with an insulator provided on a conductor, or a multi-core twist of these and an inclusion. The present invention relates to the sheath of the cable sheathed through and/or the flame-retardant cable used as the insulator. If necessary, the surface of the magnesium hydroxide is treated with stearic acid or oleic acid, and the rubber and plastic used have a 90% ethylene content.
One type or a combination of two or more of the above polyolefin resins are used, and a flame retardant containing red phosphorus is added, and in the case of cables, the inclusions between the twisted core and sheath are made of halogen elements. It is possible to produce a flame-retardant composition that does not contain any of the following: and has an oxygen index value of 30 or more.

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

Here, the sheath 4 is made of the flame retardant composition of the present invention, that is, 100 parts by weight of rubber or plastic that does not contain halogen elements, and 50 to 200 parts by weight of magnesium hydroxide having an average particle size of 0.3 μm to 2 μm. Oil absorption iiQ, 5ml1/g
~2.0mj! /g carbon blank powder 5-50 parts by weight, organopolysiloxane 3-10 parts by weight, halogen-free xPbo ・Pb (R) ・yH
z Basic lead compound represented by O (however, 0≦x≦3,
R is a sulfuric acid group, a higher fatty acid having 6 or more carbon atoms, or an aromatic carboxylic acid, and 0≦y≦10. or a flame-retardant mixture crosslinked with a sulfur compound vulcanizing agent. The insulator 2 is made of the same flame-retardant composition as the sheath 4, or is made of ordinary rubber or plastic that also does not contain halogen elements. The interposition 3a in Fig. 1 is a normal interposition formed of paper tape, jute, etc., and the interposition 3b in Fig. 2 is formed of a flame-retardant composition that does not contain a halogen element and has an oxygen index value of 30 or more. This is a fulfilling type of intervention. In the case of this solid type interposition, preferably, in order to prevent fusion between the core and sheath, a core tape 5 such as mylar is wrapped around the core as described above, and a restraining tape 6 is applied over the solid interposition. Wrap it around.

As mentioned above, the flame-retardant composition of the present invention and the flame-retardant cable using the same are composed of a non-halogen rubber and plastic-based resin and a non-halogen additive that do not contain any halogen elements, so they are less likely to cause fires, etc. Even if it encounters and combusts, the combustion gas does not contain harmful gases such as hydrogen halide gas, so it will not corrode the metal around the cable installation and will not have any harmful effects on the human body. .

In addition, as magnesium hydroxide that causes an endothermic reaction by releasing crystal water is added with a specific particle size (0.3 μm to 2 μm), even with relatively high loading, mechanical properties may deteriorate or processing during extrusion may occur. In particular, in the case of magnesium hydroxide, the temperature at which water of crystallization is released is around 200°C (this temperature is higher than that of aluminum hydroxide). , depending on the resin, it is higher than the thermal decomposition temperature of the resin (which is the temperature that limits the use of the resin), which is around 370 ° C.
It is close to the thermal decomposition temperature of the base resin, so there are almost no restrictions on the kneading temperature or extrusion temperature of the resin used.

Furthermore, if magnesium hydroxide is surface-treated with stearic acid or oleic acid, even more filling becomes possible and good processability is obtained. In addition, as a carbon blank, a specific oil absorption amount (0.5mβ/g ~ 2.0mj!/g
) Since it is added later, the flame retardant effect is large because the particle size is small and the surface area is large, and a sufficient flame retardant effect can be obtained by adding a small amount. Further, during combustion, the carbon blank in this composition is heated in a state where oxygen is cut off, so that it is carbonized and a carbonized layer is formed in the composition. The formation of this carbonized layer effectively suppresses the flow of the composition itself and the outflow of combustible materials from inside the cable (melt drip), thereby further preventing the spread of fire.

In addition, organopolysiloxane (generally treated as silicone rubber) and xPbO with the above specific properties
Flame retardancy can be improved by adding it in combination with a basic lead compound represented by -Pb(R).yH20. A sufficient flame retardant effect can be obtained with a small amount of these additives.

Furthermore, when a certain amount of red phosphorus is added, the carbonization effect in the composition is further promoted during combustion. That is, when red phosphorus is heated to a high temperature and oxidized, hydrogen is taken away from the resin and dehydrated, thereby promoting carbonization of the resin. This dehydration and carbonization effect can be achieved with a small amount of red phosphorus, and it is best to use it in combination with the above-mentioned magnesium hydroxide.

Moreover, since the flame retardant composition is crosslinked by the hot-flow treatment of peroxide, sulfur, or a sulfur-based compound, it also has excellent mechanical properties. Furthermore, since it uses magnesium hydroxide with a specific particle size, carbon black with a specific oil absorption amount, and red phosphorus, which are good materials for flame retardation, conventional flame retardants containing halogens such as chlorine and bromine can be used. The amount of smoke emitted is also lower than that of

Further, as in the cable shown in Fig. 2, when a flame-retardant composition that does not contain a halogen element and has an oxygen index value of 30 or more is used for the intervening material, a sheath formed of the flame-retardant composition of the present invention is used. In combination with or/and the structure with an insulator, even higher flame retardance can be obtained.

The rubbers and plastics used in the present invention are so-called non-halogen rubbers and plastics that do not contain halogen elements, such as PE, natural rubber, butyl rubber, silicone rubber, ethylene propylene rubber (EPM), ethylene propylene diene elastomer (EPDM), and ethylene. −
Examples include vinyl acetate copolymers, ethylene and ethyl acrylate copolymers, ethylene and α-olefin copolymers, ethylene acrylic elastomers, hydrogenated styrene butadiene elastomers, and blends thereof. In order to obtain good mechanical properties such as high tensile strength, it is preferable to use one or a combination of two or more polyolefin resins containing 90% or more of ethylene.

Moreover, the average particle diameter of the magnesium hydroxide of the present invention is 0.3
μm to 2 μm is because if it is less than 0.3 μm, the cohesive force will be large and dispersion in the mixture will be poor, which will have a negative effect on mechanical properties, etc. If it exceeds 2 μm, the adhesion with the resin will be poor. This is because mechanical properties such as , tensile strength, and elongation deteriorate, which is undesirable. The reason why the amount added is set at 50 to 200 parts by weight is that if it is less than 500 parts by weight, a sufficient flame retardant effect cannot be obtained, and if it exceeds 200 parts by weight, it is too much and the mechanical properties may deteriorate. , during extrusion,
This is because foaming may occur and workability may deteriorate.

In addition, the oil absorption amount of the carbon black of the present invention is 0°5mj!
/g ~2.0m1t/g because of its high flame retardant effect,
This is because it has both good processability and excellent mechanical properties, and if it is less than 0.5 mA/g, the tensile strength is low and the flame retardant effect is also small.
If it exceeds g, the viscosity of the mixture will be high, resulting in poor processing and deterioration of electrical insulation properties. The reason why the amount added is set to 5 to 50 parts by weight is that if it is less than 5 parts by weight, the desired flame retardant effect and carbonized layer forming effect cannot be obtained, and if it exceeds 50 parts by weight, the viscosity of the mixture increases. This is because processability becomes poor and elongation decreases.

Furthermore, examples of the organopolysiloxane used in the present invention include dimethylpolysiloxane, methylphenylpolysiloxane, and methylvinylpolysiloxane. Moreover, xPb which does not contain a halogen element of the present invention is used in combination with this.

・Pb(R) ・) A basic lead compound represented by 1H2O (where 0≦x≦3, R is a sulfuric acid group, a higher fatty acid having 6 or more carbon atoms, or an aromatic carboxylic acid, and O≦y≦
10) or these surface-treated compounds include, for example, tribasic lead sulfate, dibasic lead phthalate,
Examples include basic lead stearate. The reason for setting the amount of each of these additives to 3 to 10 parts by weight is that if the amount is less than 3 parts by weight, the effect of improving flame retardancy will hardly be obtained.
On the other hand, if it exceeds 10 parts by weight and the total amount of both is too large, the tensile strength will decrease, but the flame retardance will not be improved much compared to the addition, and it will be expensive, which is unfavorable from a cost standpoint.

In addition, 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, because if it is less than 2 parts by weight, almost no effect of promoting carbonization can be obtained. This is because if the amount exceeds the weight part, the flame retardance will conversely decrease and smoke generation will increase, which is undesirable.

Further, as the preflow agent used in the present invention, in the case of peroxide additive treatment, for example, DCP (dicumyl peroxide), 2.
Examples include 5-dimethyl-2,5-di(t-butylperoxine)hexane, 2,5-dimethyl-2,5-di(t-butylperoxy)hexine, and t-butylperbenzoate.

Other vulcanizing agents include sulfur or a combination of a thiuram-based vulcanizing agent and a sulfur-based compound.

In manufacturing the above-mentioned cable, the insulator and sheath are extruded using a conventional extrusion method. If paper tape or jute is used, it can be filled vertically. In the case of solid interposition, it depends on the extrusion method.

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

<Examples> Table 1 shows examples ■ to ■ of the flame retardant composition according to the present invention.
are shown together with the results of each characteristic test. Table 2 also shows compositions that do not meet the requirements of the present invention and ordinary polyvinyl chloride compositions as Comparative Examples (1) to (2) along with the results of their respective characteristic tests.

From Table 1 above, it can be seen that each flame retardant composition of the present invention satisfies the performance shown below and exhibits excellent characteristics when each compounding material is set within a desired range.

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

Mooney viscosity ≦35 Fuming property ≦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 Comparative Example (2), when the total amount of organopolysiloxane and basic lead compound is too large, the tensile strength decreases, but the flame retardance does not increase so much. Comparative example ■ is a case where a flame retardant containing bromine (decabromodiphenyl oxide) is used.
A large amount of hydrogen bromide gas is generated, as well as a large amount of smoke. Comparative examples ■ and ■ are compositions containing chlorine, and 0■ has a well-balanced tensile strength, but is smoke-emitting, generates a lot of hydrogen halide gas, and is corrosive and toxic. Undesirable.

Table 3 shows each example of the flame-retardant cable according to the present invention.
(2) is shown together with the results of each characteristic test. Table 4 also shows cables using compositions that do not meet the requirements of the present invention and ordinary polyvinyl chloride compositions as comparative examples.
~■ are shown together with the results of each characteristic test.

From Table 3 above, each flame-retardant cable of the present invention is all I
It can be seen that it has passed EEE Std, 383. That is, the finished appearance was good, there was no generation of hydrogen chloride gas, and there was little smoke generation, and the visibility distance was improved to 100 m or more in all cases. It is also understood that in order to obtain high flame retardancy, it is better to provide a flame retardant enriched intervening material.

On the other hand, from Table 4 above, Comparative Example (3) has a sheath made flame retardant with a flame retardant containing bromine, and although it passes the combustion test, it is expected that hydrogen bromide gas will be generated. It also produces a lot of smoke and has a short visibility distance. Comparative Examples ① to ② were all PvC sheaths, and although they passed the combustion test, a large amount of hydrogen chloride gas was generated, corroding metals in the event of a fire, and being harmful to the human body. There was also a lot of smoke.

<Effects of the Invention> As is clear from the above description, the present invention has high flame retardancy, and the combustion gas does not contain hydrogen halide gas, etc., which corrodes surrounding metals. To provide an unprecedented so-called clean flame-retardant composition and flame-retardant cable that have no harmful effects on the human body, emit little smoke, and have excellent mechanical properties. I can do it.

[Brief explanation of drawings]

1 and 2 are longitudinal sectional views of a flame-retardant cable using the flame-retardant composition according to the present invention. DESCRIPTION OF SYMBOLS 1... Conductor, 2... Insulator, 3a, 3b... Interposition, 4... Sheath. Figure 1 Figure 2 Procedural amendment written format) % formula % 2. Name of the invention Flame-retardant composition and flame-retardant cable using the same 3. Relationship with the person making the amendment Patent applicant address Tokyo Koto-ku Kiba-chome 5-1 Name Fujikura
Electric Wire Co., Ltd. Representative Makoto Kagaya - 4, Agent 141! 103 (440)
-6761 Address: 5-23-1 Higashigotanda, Tokyo Parts Ward
No.6, Subject of amendment

Claims (6)

[Claims] (1) Rubber and plastic that do not contain halogen elements 1
00 parts by weight, 50 to 200 parts by weight of magnesium hydroxide with an average particle diameter of 0.3 μm to 2 μm, and an oil absorption of 0.5 ml.
/g~2.0ml/g carbon black powder 5~50
Parts by weight, organopolysiloxane 3 to 10 parts by weight, xP
A basic lead compound represented by bO-Pb(R)・yH_2O (where 0≦x≦3, R is a sulfuric acid group, a higher fatty acid having 6 or more carbon atoms, or an aromatic carboxylic acid, and 0≦y≦
A flame-retardant composition characterized in that a mixture obtained by adding and mixing 3 to 10 parts by weight of 10) is crosslinked with a vulcanizing agent of organic peroxide, sulfur, or a sulfur-based compound. (2) Rubber and plastics that do not contain halogen elements 1
00 parts by weight, 50 to 200 parts by weight of magnesium hydroxide with an average particle diameter of 0.3 μm to 2 μm, and an oil absorption of 0.5 ml.
/g~2.0ml/g carbon black powder 5~50
Parts by weight, organopolysiloxane 3 to 10 parts by weight, xP
A basic lead compound represented by bO-Pb(R)・yH_2O (where 0≦x≦3, R is a sulfuric acid group, a higher fatty acid having 6 or more carbon atoms, or an aromatic carboxylic acid, and 0≦y≦
A flame retardant composition obtained by adding and mixing 3 to 10 parts by weight of 10) with a vulcanizing agent of organic peroxide, sulfur, or a sulfur-based compound is used to form an insulator on a conductor. 1. A flame-retardant cable characterized in that it is used as the sheath and/or the insulator of a cable in which a cable core is provided, or a cable is formed by twisting these into a multi-core structure and sheathing the cable via an inclusion. (3) The flame-retardant composition according to claim 1, wherein the magnesium hydroxide is surface-treated with stearic acid or oleic acid; The flame-retardant cable described in item 2. (4) In the flame-retardant composition, the rubber or plastic contains one or a combination of two or more polyolefin resins whose ethylene content is 90% or more. The flame-retardant composition according to item 1 or 3, or the flame-retardant cable according to item 2 or 3. (5) In the flame retardant composition, a flame retardant containing red phosphorus is added so that the red phosphorus component in the composition is 2 to 15 parts by weight. 1
The flame-retardant composition according to item 1, 3 or 4, or the flame-retardant cable according to item 2, 3 or 4. (6) In the cable coated with the flame retardant composition, an inclusion provided between the twisted core and the sheath,
The flame retardancy according to claim 2, 3, 4 or 5, which is made of a flame retardant composition that does not contain a halogen element and has an oxygen index value of 30 or more. cable.