JP2001354826A - Flame-retardant resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a halogen-free flame-retardant resin composition having excellent flame-retardancy and abrasion resistance, free from whitening trouble of molded article, exhibiting good shape recovery and suitable as a coating material for electric cable of car, etc. SOLUTION: The resin composition is produced by compounding 100 pts. of a blend polymer composed of 20-80 wt.% polypropylene block copolymer and 80-20 wt.% hydrogenated SBR with 40-80 pts.wt. of a metal hydroxide, 3-20 pts.wt. of zinc hydroxystannate and/or zinc stannate and 3-10 pts.wt. of ammonium polyphosphate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flame-retardant resin composition suitable for covering materials such as electric wires for automobiles.

[0002]

2. Description of the Related Art Automotive electric wires are required to have good flame retardancy, high abrasion resistance, and low cost for the purpose of use. For this reason, plasticized polyvinyl chloride compositions have been mainly used for covering materials such as insulators and sheaths of automobile electric wires. However, the use of halogen-containing polymers such as polyvinyl chloride is being reviewed due to recent environmental problems.

[0003] For this reason, it has been studied to construct a covering material for an automobile electric wire by using a non-halogen resin composition other than the plasticized polyvinyl chloride composition. As a material satisfying such requirements, a large amount of magnesium hydroxide is blended in a blend polymer of an ethylene-ethyl acrylate copolymer and a polypropylene block copolymer, and a non-halogen flame-retardant resin having flame retardancy and abrasion resistance. Compositions have been proposed.

[0004] However, this non-halogen flame-retardant resin composition has a drawback that when a molded article obtained therefrom is bent, the bent portion becomes white, and when the molded article has insufficient elasticity and is crushed. There is also a problem that the wire does not return to its original shape, and there is also a problem that when the wire having the coating material made of this resin composition is subjected to harness processing, the wire bouncing phenomenon occurs.

[0005]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a molded article which does not suffer from whitening phenomenon, has sufficient elasticity, and has sufficient elasticity to provide excellent resilience. An object of the present invention is to obtain a non-halogen flame-retardant resin composition which is rich and does not cause wire splashing when used as an electric wire, and is suitable as a coating material for automobile electric wires and the like.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a blend of a polypropylene block polymer and a hydrogenated styrene-butadiene rubber as a base polymer, and 100 parts (parts by weight, hereinafter the same) of the base polymer to a metal hydroxide. The problem is solved by a resin composition containing 40 to 80 parts, zinc hydroxystannate and / or zinc stannate 3 to 20 parts, and ammonium polyphosphate 3 to 10 parts.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
As the base polymer of the flame-retardant resin composition of the present invention, a blend polymer of a polypropylene block copolymer and a hydrogenated styrene-butadiene rubber (HSBR) is used. The polypropylene block copolymer is a block copolymer of propylene and ethylene, having an ethylene content of 5 to 30 mol% and a melt index (230 ° C,
2.16 kg) in the range of 0.5 to 2 is used. This polymer has a high-order structure in which a homopolymer of propylene and a copolymer portion of ethylene and propylene are dispersed in a matrix, and is a polymer having high rigidity and high impact resistance.

[0008] Hydrogenated styrene butadiene rubber (HSB)
R) is a type of thermoplastic elastomer and is a block copolymer of styrene and hydrogenated butadiene;
It comprises a crystalline hard segment of polystyrene and a soft segment of amorphous hydrogenated polybutadiene. The physical properties of this elastomer vary depending on the ratio of styrene to hydrogenated butadiene. In the present invention, those having a styrene content of 20 to 50 mol% are suitably used.

The mixing ratio of the polypropylene block copolymer and the hydrogenated styrene-butadiene rubber is 20 to 80% by weight for the polypropylene block copolymer and 80 to 20% by weight for the hydrogenated styrene-butadiene rubber. When the content of the polypropylene block copolymer is 20
If the amount is less than 80% by weight, the wear resistance becomes insufficient.
If the ratio exceeds the above, flexibility and whitening properties become insufficient. A preferable mixing ratio of both is that the polypropylene block copolymer is 6
0-80% by weight, hydrogenated styrene butadiene rubber is 20-40% by weight.

[0010] A metal hydroxide as a flame retardant is blended with the base polymer comprising the blend polymer. As the metal hydroxide, one or a mixture of two or more of magnesium hydroxide, aluminum hydroxide, calcium hydroxide and the like is used. Among them, magnesium hydroxide having a high flame-retardant effect is preferable. The amount of the metal hydroxide to be compounded is determined by the flame retardancy required of the flame retardant resin composition. If it is less than 40 parts, the flame retardancy is insufficient, and if it exceeds 80 parts, the mechanical properties deteriorate.

Further, as a flame retardant aid, 3 to 20 parts of zinc hydroxystannate and / or zinc stannate are blended with respect to 100 parts of the base polymer, and 3 to 10 parts of ammonium polyphosphate is blended with respect to 100 parts of the base polymer. You. Zinc hydroxystannate, zinc stannate, and ammonium polyphosphate are all non-halogen-based compounds having a high flame retardant effect. These compounds reduce the amount of metal hydroxide to provide sufficient flame retardancy. It is possible to simultaneously obtain properties that are incompatible with high mechanical properties.

The compounding amounts of these flame-retardant assistants are as described above. However, in order to obtain a predetermined flame retardancy, when the compounding amount of the metal hydroxide is as small as 40 to 50 parts, these difficult-to-fire additives are used. It is necessary to mix the fuel aid with a large amount of 20 to 30 parts in total,
When the compounding amount of the metal hydroxide is as large as 60 to 80 parts,
What is necessary is just to mix about 10 to 20 parts of these flame retardant aids in total.

The blending of the flame retardant and the flame retardant auxiliary lowers the mechanical properties such as the tensile strength, elongation, and abrasion resistance of the flame retardant resin composition. In consideration of the required flame retardancy, it is appropriately determined within the above range.

The flame-retardant resin composition of the present invention may contain, if necessary, an antioxidant, an ultraviolet absorber, a coloring agent, an inorganic filler,
An additive such as a cross-linking agent can be appropriately compounded. It is also possible to increase the flame retardancy by adding 10 parts or less of a silicone flame retardant such as silicone powder or silicone gum, or to reduce the amount of the metal hydroxide.

The electric wire of the present invention has a covering material such as an insulator or a sheath made of the above-described flame-retardant resin composition. The formation of these coating materials is performed by a usual extrusion coating method, and if a crosslinked coating material is required as a coating material, a composition containing a crosslinking agent such as dicumyl peroxide is used, and after extrusion coating, What is necessary is just to send to a bridge | crosslinking apparatus and to heat and to bridge | crosslink.

The flame-retardant resin composition of the present invention does not contain a halogen element such as chlorine in the composition,
It is non-halogen and has good flame retardancy and high mechanical properties such as abrasion resistance. Moreover, even if this is incinerated, no harmful substances such as dioxin are generated. Further, even if a molded article obtained from the flame-retardant resin composition is bent, the bent portion does not become white. In addition, it is rich in elasticity and immediately restores its original shape without plastic deformation even when the molded product is pressed. In addition, when a wire having a coating made of this composition is subjected to harness processing, wire bouncing does not occur.

Therefore, the flame-retardant resin composition of the present invention comprises:
Various molded articles such as various electric wires such as automobile electric wires, covering materials of cables, electric conduits, pipes, plates, sheets and the like can be obtained.

The following is a specific example. A flame-retardant composition having the composition shown in Tables 1 and 2 (expressed in parts by weight) was prepared, extruded and coated on a conductor having a cross-sectional area of 0.5 mm ² to form an electric wire having an outer diameter of 1.6 mm. did. This wire was subjected to a wear test in accordance with JASO D611 wear test, a blade reciprocating method, and a wire was evaluated as 150 times or more.
Further, the combustion test was performed in accordance with the JASO D611 horizontal combustion test, and a fire was self-extinguished within 15 seconds in all three trials.

The same flame-retardant resin composition was extruded into a sheet having a thickness of 2 mm, and the sheet was used as a test piece to measure the tensile strength, elongation, and the presence or absence of whitening when the sheet was bent at 90 degrees. did. Tables 1 and 2 show the results.
As the polypropylene block polymers in Tables 1 and 2, those having a melt index (230 ° C.) of 1 were used.

[0020]

[Table 1]

[0021]

[Table 2]

[0022]

As described above, the flame-retardant resin composition of the present invention is non-halogen, has high flame retardancy and mechanical properties, and a molded article obtained therefrom has a whitening effect. The phenomenon does not occur, the elasticity is high, and the shape restoring property is good. For this reason, it is suitable as a covering material for electric wires for automobiles and the like.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) H01B 3/00 H01B 3/00 A 3/28 3/28 3/30 3/30 N 3/44 3/44 G 7 / 29 7/34 A F term (reference) 4J002 AC11X BP02W DE076 DE086 DE146 DE187 DH058 FD136 GQ01 5G303 AA06 AA08 AB20 BA12 CA09 CA11 5G305 AA02 AB18 AB25 AB35 AB40 BA13 CA01 CA02 CA08 CA47 CA51 CA52 CC03 CC03 CD01 CD03 CD03 CD03 CD14 CD17

Claims (3)

[Claims] 1 to 40 parts by weight of a metal hydroxide, 3 to 20 parts by weight of zinc hydroxystannate and / or zinc stannate based on 100 parts by weight of a blend polymer comprising a polypropylene block copolymer and a hydrogenated styrene-butadiene rubber. And a flame retardant resin composition comprising 3 to 10 parts by weight of ammonium polyphosphate. 2. The flame-retardant resin composition according to claim 1, wherein the blend polymer comprises 20 to 80% by weight of a polypropylene block copolymer and 80 to 20% by weight of a hydrogenated styrene-butadiene rubber. 3. An electric wire having a coating comprising the flame-retardant resin composition according to claim 1.