JP2000080210A - Elastomer composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a halogen-free elastomer composition having improved flexibility and elasticity while maintaining heat resistance and abrasion resistance of a composition containing an olefin-based elastomer and a flame retardant, suitable for a part material of wire harness, etc. SOLUTION: This elastomer composition comprises 70-90 pts.wt. of an olefin- based elastomer such as a propylene-ethylene-propylene copolymer, 30-10 pts.wt. of a hydrogenated styrene/butadiene rubber and a flame retardant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an elastomer composition, and more particularly, to an elastomer composition suitable as a material used for exterior parts such as tubes and sheets of automobile wire harnesses.

[0002]

2. Description of the Related Art In consideration of environmental measures, halogen-free materials have come to be used for manufacturing components such as tubes and sheets for automobile wire harnesses. Conventional halogen-free materials add heat resistance and abrasion resistance to olefin-based elastomers, such as propylene-ethylene-propylene copolymers, to which metal hydroxides are added as flame retardants, and furthermore, fatty acid salts as lubricants. Is used.

[0003] A composition comprising an olefin polymer and hydrogenated styrene-butadiene rubber is disclosed in Japanese Unexamined Patent Publication No.
No. 45278 and JP-A-9-220898. However, the compositions described in these publications are used for stationery such as file binders and desk mats, and are not provided with flame retardancy, so that they are not suitable as component materials for wire harnesses for automobiles. Also, the olefin polymers described are resins, not elastomers.

[0004]

However, the composition containing the propylene-ethylene-propylene copolymer, the flame retardant and the lubricant is excellent in heat resistance and abrasion resistance, but is inferior in flexibility and elasticity. Therefore, there is a problem that the tube may be broken during winding operation in manufacturing the tube, or may be crushed when sandwiched between the feed rollers at the time of cutting the scale, and the tube may not be restored. On the other hand, as described above, the compositions described in JP-A-7-145278 and JP-A-9-220898 contain a resin as a main component and do not have flame retardancy. Not suitable as wire harness parts material. Accordingly, an object of the present invention is to provide an elastomer composition which has solved the above-mentioned disadvantages of a conventional composition containing a propylene-ethylene-propylene copolymer, a flame retardant and a lubricant.

[0005]

According to the present invention, there is provided an elastomer composition comprising 70 to 90 parts by weight of an olefinic elastomer, 30 to 10 parts by weight of a hydrogenated styrene / butadiene rubber, and a flame retardant. Offer things.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, an olefin-based elastomer is an elastomer containing an olefin as a main component (that is, 50% by weight or more of a repeating unit). The olefin has 2 to 6 carbon atoms, preferably 2 carbon atoms.
Preferred are olefins 4 to 4, such as ethylene, propylene, and butylene. The olefin-based elastomer may be a homopolymer or a copolymer, and the type of the copolymer is not limited.

[0007] Hydrogenated styrene-butadiene rubber is obtained by hydrogenating styrene-butadiene rubber, and either a block copolymer or a random copolymer can be used in the composition of the present invention. As the hydrogenated styrene / butadiene rubber, commercially available products, for example, DYNARON HSBR1
320P (10% styrene content) and 1910P (30% styrene content) can be used.

The amount of the olefin elastomer and the hydrogenated styrene / butadiene rubber in the composition of the present invention is 30 to 10 parts by weight of the hydrogenated styrene / butadiene rubber with respect to 70 to 90 parts by weight of the olefin elastomer. If the amount of the hydrogenated styrene-butadiene rubber is less than the above lower limit, the flexibility and elasticity of the composition cannot be improved. On the other hand, when the amount of the hydrogenated styrene / butadiene rubber exceeds the above upper limit, the wear resistance of the olefin elastomer is impaired, and the wear resistance of the entire composition is reduced.

As the flame retardant, any flame retardant used in conventional elastomer compositions and the like can be used. Examples of preferred flame retardants are metal hydroxides (e.g., magnesium hydroxide, aluminum hydroxide, etc.), others, phosphate esters, phosphorus compounds and the like. The compounding amount of the flame retardant is 50 to 150 parts by weight, preferably 80 to 120 parts by weight, per 100 parts by weight of the total of the olefin elastomer and the hydrogenated styrene / butadiene rubber. Within this range, good flame retardancy can be imparted to the composition.

[0010] The composition of the present invention may contain any of the additives usually added to elastomer compositions conventionally used as component materials for wire harnesses. Examples of such additives are lubricants (eg, fatty acids, fatty acid metal salts, fatty acid amides, etc.), various colorants, antistatic agents and the like. The amount of the additive may be appropriately selected according to the type of the additive.

The hydrogenated styrene-butadiene rubber has good compatibility with the crystalline polyolefin and is excellent in flexibility and elasticity, so that it can be easily kneaded with the olefin elastomer and has excellent flexibility and composition in the composition. Elasticity can be imparted. Also, because it is hydrogenated,
The heat resistance of the composition does not decrease. Further, since the composition of the present invention maintains a high proportion of the olefin-based elastomer, the composition can maintain sufficient abrasion resistance.

[0012]

The present invention will be described below in detail with reference to examples and comparative examples. Example 1-3 and Comparative Example 1-3 The components shown in Table 1 were used in the amounts shown in Table 1, and kneaded at 170 ° C. for 10 minutes with a pressurized kneader (capacity: 20 liters), followed by use of a pelletizer. Pelletized. 5
Using a 0 mmφ extruder, a protective tube (0.4 mm thick, 10 mm inner diameter) for a wire harness was extruded from the obtained pellets at a die temperature of 180 ° C. and a linear speed of 35 m / min. When the obtained tube was subjected to a natural winding treatment with a diameter of 400 mm, the tube could be wound well without any breakage. In addition, the natural winding means that the manufactured tube is freely dropped and spirally wound. In addition, the tube manufactured in the example did not crush even at the time of cutting with a 50 mmφ opposed roller feeder. In addition, about the obtained tube,
As a result of a heat resistance and abrasion resistance test, the product of the example had characteristics equivalent to those of the conventional product of the comparative example 1.

The heat resistance and abrasion resistance were tested as follows. Heat resistance JIS K6303 No. 3 dumbbell pieces were prepared and subjected to heat aging at 100 ° C. for 120 hours during gear opening. Thereafter, a tensile test was performed at a crosshead speed of 200 mm / min, and the elongation at break was measured. The residual elongation was calculated based on the elongation at break of the unheated aged product. Abrasion resistance A tube having an inner diameter of 10 mm is passed through a metal rod having an outer diameter of 10 mm, and a tube test piece is fixed so as to be in contact with the abrasion tape of the polishing pad 150-AA. A load of 450 gf is applied, and the tape is placed at the same position of the tube. 1500mm /
Run the tape at a speed of min and read the running length of the tape until the metal bar is exposed and comes into contact with the tape (when the tube wears out).

The above results are summarized in Table 1.

[Table 1]

According to the present invention, by blending a hydrogenated styrene / butadiene rubber which is flexible and excellent in elasticity with an olefin elastomer, heat resistance and abrasion resistance are not impaired, and workability (rolling after extrusion molding) is improved. Wire harness exterior protection material that has excellent properties (heat resistance, abrasion resistance, etc.) as an exterior part and does not contain environmentally harmful halogen elements. Can be provided.

Claims (3)

[Claims] 1. An elastomer composition comprising 70 to 90 parts by weight of an olefinic elastomer, 30 to 10 parts by weight of a hydrogenated styrene / butadiene rubber, and a flame retardant. 2. The elastomer composition according to claim 1, wherein the olefin-based elastomer is a propylene-ethylene-propylene copolymer. 3. The elastomer composition according to claim 1, wherein the flame retardant is contained in an amount of 50 to 150 parts by weight per 100 parts by weight of the total of the olefin-based elastomer and the hydrogenated styrene-butadiene rubber.