JP2001270967A - Olefin elastomer composition and method for molding the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an olefin elatomer composition that has flame resistance equal to that of polyvinyl chloride and can satisfy the requirements especially on abrasion resistance as a protective tube or sheet for wiring harness for a vehicle. SOLUTION: The olefin elastomer composition comprises 12.5-30 wt.% styrene elastomer, at least 5.5 wt.% bromine containing flame retardant (as a weight of bromine), at least 2.5 wt.% antimony trioxide and at least 0.5 wt.% lubricant, based on the weight of the total composition, blended into an olefin elastomer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an olefin-based elastomer composition and a method for molding the same, and more particularly, to an olefin-based elastomer composition useful as a material for a protective tube and a sheet of an electric wire used in a wire harness for automobiles. And its forming method.

[0002]

2. Description of the Related Art Up to now, protective tubes and sheets for automobile wire harness electric wires have been mainly formed of polyvinyl chloride (PVC). However, in consideration of recent global environmental measures, halogen-free materials have come to be used instead of polyvinyl chloride in the production of automotive wiring harness component materials, such as tubes and sheets. To maintain the abrasion resistance and flame retardancy of halogen-free materials sufficiently high and to measure weight reduction, (soft)
Compositions in which a bromine-based flame retardant is added as a flame retardant to an olefin-based elastomer or a composition in which a styrene-based elastomer is added to impart flexibility (Japanese Patent Laid-Open No. 9-1433)
No. 08 publication) has been proposed.

[0003] When a styrene-based elastomer is added to an olefin-based elastomer, the cost of the entire composition is reduced because the styrene-based elastomer has a relatively low material unit price. Properties, for example, tensile strength, tensile elongation, etc., are reduced.

[0004]

DISCLOSURE OF THE INVENTION The present invention relates to an olefin elastomer having flame retardancy equivalent to that of PVC and satisfying properties as a protective tube and a sheet for a wire harness electric wire for automobiles, especially abrasion resistance. It is intended to provide a composition. Another object of the present invention is to provide a method for molding such an olefin-based elastomer composition.

[0005]

According to the present invention, in order to solve the above-mentioned problems, 12.5 to 30% by weight of a styrene-based elastomer, based on the weight of the whole composition, a brominated flame retardant (in terms of bromine element weight) A) an olefinic elastomer composition comprising at least 5.5% by weight, at least 2.5% by weight of antimony trioxide, and at least 0.5% by weight of a lubricant.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, each component contained in the composition of the present invention will be described. In the present invention, as the olefin-based elastomer, an elastomer containing an olefin as a main component (that is, 50% by weight or more of a repeating unit) can be used. As the olefin, an olefin having 2 to 6 carbon atoms, preferably 2 to 4 carbon atoms, for example, ethylene, propylene, butylene and the like are preferable. The olefin-based elastomer may be a homopolymer or a copolymer, and the type of the copolymer is not limited.
For example, a propylene-ethylene-propylene copolymer can be preferably used.

[0007] As the styrene-based elastomer, an elastomer containing styrene as a main component can be used. For example, styrene-butadiene-styrene copolymer (SBS), styrene-isoprene-styrene copolymer (SIS) and the like can be preferably used. The amount of the styrene-based elastomer is usually 12.5 to 30% by weight, preferably 12.8 to 25% by weight based on the total weight of the composition.
% By weight. If the amount of the styrene elastomer is less than the above lower limit, sufficient flexibility cannot be imparted to the composition. On the other hand, if the amount of the styrene-based elastomer exceeds the above upper limit, physical properties of the composition, for example, tensile strength,
The tensile elongation etc. decrease.

[0008] The type of brominated flame retardant is not particularly limited, and brominated flame retardants conventionally used as flame retardants such as resins and rubbers can be used. Preferred examples of the bromine-containing compound that can be used as a flame retardant include a derivative of tetrabromobisphenol A. Commercially available flame retardants include Fireguard 3100 (bromine element content: 65% by weight) manufactured by Teijin Chemicals Limited and Flamecut 1 manufactured by Tosoh Corporation.
21R (bromine element content: 67% by weight).

The amount of the brominated flame retardant is at least 5.5 in terms of elemental bromine weight based on the weight of the whole composition.
% By weight, preferably 5.5 to 20.5% by weight. When the amount of the brominated flame retardant is less than the above lower limit, the composition cannot have a sufficient flame retardant effect. Although the upper limit is not particularly limited, if the amount of the brominated flame retardant is too large, the specific gravity of the composition may increase, and the composition may not be reduced in weight.

The amount of antimony trioxide is at least 2.5% by weight, preferably 2.5 to 10.3% by weight, based on the total weight of the composition. If the amount of antimony trioxide is less than 2.5% by weight, sufficient flame retardancy cannot be imparted. Although the upper limit is not particularly limited, if the amount of antimony trioxide is too large, the specific gravity of the composition becomes large.

The composition of the present invention may contain any of the additives usually added to elastomer compositions conventionally used as wire harness component materials. 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 olefin-based elastomer composition of the present invention can be produced by mixing the above essential components and desired components. In this case, the olefin elastomer composition has a temperature of 145 to 160 ° C. so that the temperature of the composition does not exceed 170 ° C. It is preferred to carry out mixing. Also, when molding the olefin-based elastomer composition of the present invention, it is preferable to perform molding at 150 to 160 ° C so that the composition temperature does not exceed 170 ° C. When the composition temperature exceeds 170 ° C., the styrenic polymer decomposes, thereby generating an offensive odor. In addition, the physical properties of the composition such as tensile strength also decrease.

Although the olefin elastomer composition of the present invention has a halogen content (by weight) reduced to about 1/10 or less as compared with PVC, the olefin elastomer composition has a low PV content.
It has flame retardancy equal to or higher than C, and the specific gravity of the composition can be 1.0 or less. Further, since the olefin elastomer composition of the present invention is excellent in abrasion resistance, when it is used as an electric wire protection tube for a wire harness, its thickness is 0.5 mm (in the case of PVC) to 0.1 mm.
It can be reduced to 35 mm, and therefore the component weight can be reduced.

[0014]

Examples 1 to 4 and Comparative Examples 1 to 5 The components shown in Tables 1 and 2 were kneaded for 10 minutes at 145 to 160 ° C. using a pressure kneader (capacity: 20 liters), and pelletized with a pelletizer. It has become. In Comparative Example 5, a vinyl chloride resin alone was used. The amounts of the components in the table are "parts by weight". Using these pellets, diameter 50m
extruder at a die temperature of 150 to 160 ° C. and a linear speed of 35 m / min.
A 0 mm tube was obtained.

The obtained tubes were measured or evaluated for tensile strength, flame retardancy and abrasion resistance by the following methods. A No. 3 dumbbell specified in JIS K6251 was formed from the tensile strength composition, and the dumbbell was attached to a tester specified in JIS B7721 and pulled at a speed of 200 mm / min to measure the strength at break. The lower limit of the tensile strength required for the wire protection tube for a wire harness is 15.
7 MPa. According to flammability JIS K 7201, oxygen index is measured,
The flame retardancy was evaluated. The lower limit of the oxygen index required for the wire protection tube for a wire harness is 27. Abrasion resistance A tape abrasion test was performed as follows. Inner diameter 10
A tape abrasion test was performed using a tube having a diameter of 2 mm with a wear resistance test apparatus shown in FIG. A test piece was fixed through a metal rod through a tube so as to be in contact with a 150-AA wear tape, a load of 450 gf was applied, and the wear tape was moved at a speed of 1500 mm / min until the tape came into contact with the conductor. Read the required length of the wear tape. As shown in FIG. 1, the wear tape comes into contact with the tube by approaching the tube at an angle of 30 degrees with respect to the longitudinal direction of the tube.
The tube was run around a 17 mm diameter cylinder away from the tube at an angle of degrees. The lower limit of the abrasion required for the wire protection tube for a wire harness is 150 cm.
The results are shown in Tables 1 and 2.

[0016]

[Table 1] Notes: 1) Cataloy KS-353P (Montel). 2) Clayton D1107 (manufactured by Shell). 3) Clayton D1101 (manufactured by Shell). 4) Fireguard 3100 (manufactured by Teijin Chemicals Limited, bromine content: 65% by weight). 5) Mikuni Seiren Co., Ltd. 6) Made by Sakai Chemical Co., Ltd. 7) Weight ratio when the same volume of PVC is set to 100.

[0017]

[Table 2] note:

[Brief description of the drawings]

FIG. 1 is a schematic view of a test apparatus used for evaluating wear resistance in Examples and Comparative Examples.

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Claims (4)

[Claims] 1 to 30% by weight of a styrenic elastomer, at least 5.5% by weight of a brominated flame retardant (in terms of elemental bromine weight), and at least 2.5% of antimony trioxide, based on the total weight of the composition. An olefinic elastomer composition comprising at least 0.5% by weight of a lubricant and at least 0.5% by weight of a lubricant. 2. The olefin elastomer composition according to claim 1, wherein the proportion of the styrene elastomer is 12.8 to 25% by weight based on the total weight of the composition. 3. The olefin elastomer composition according to claim 1, wherein the lubricant is a fatty acid salt. 4. A method for molding an olefin elastomer composition, comprising: kneading and molding the olefin elastomer composition according to claim 1 at a resin temperature of 170 ° C. or lower.