JP2000302923A - Elastomer composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a halogen-free elastomer composition having improved flexibility and elasticity while keeping the heat-resistance and abrasion resistance of an olefin elastomer composition, enabling the weight reduction of product and suitable as a material for part of wire harness, etc. SOLUTION: The objective elastomer composition contains 40-85 pts.wt. of an olefin elastomer, 10-30 pts.wt. of a hydrogenated styrene-butadiene rubber and 10-30 pts.wt. of a thermoplastic polyurethane or 5-10 pts.wt. of polymethyl methacrylate or ultra-high molecular weight polyethylene.

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 emphasize heat resistance and abrasion resistance, and add metal hydroxide as a flame retardant to an olefin-based elastomer, for example, a propylene-ethylene-propylene copolymer, and further use a fatty acid salt or the like as a lubricant. The added composition 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. There has been a problem that a break occurs during the picking-up operation, or the sheet is crushed when it is pinched by a feed roller at the time of cutting the scale, and is not restored. On the other hand, JP-A-7-145278 and JP-A-9-2
The composition described in 20898 is, as described above,
Since it is mainly composed of resin and does not have flame retardancy, it is not suitable as a component material for automobile wire harnesses. Therefore, the present inventors have developed an olefin-based elastomer, hydrogenated styrene / butadiene, in order to provide an elastomer composition which has solved the above-mentioned disadvantages of a composition containing a conventional propylene-ethylene-propylene copolymer, a flame retardant and a lubricant. A new elastomer composition containing rubber and a flame retardant has been developed and a patent application has already been filed (Japanese Patent Application No. 10-1998).
No. 252370. Filed on September 7, 1998).

[0005]

A product such as a wire harness for an automobile manufactured from the above-mentioned novel elastomer composition has the same abrasion resistance as a conventional product, and is equivalent to a conventional product. Used for wall thickness. Therefore, the product weight is the same as that of the conventional polyvinyl chloride product. However, from the viewpoint of protection of the global environment, reducing the weight of automobile parts and the like is preferable because it leads to reduction of energy consumption. Therefore, if the thickness of the product can be reduced while maintaining the wear resistance, a preferable product can be provided from such a viewpoint.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides 40 to 85 parts by weight of an olefin-based elastomer, 10 to 30 parts by weight of a hydrogenated styrene / butadiene rubber, and 10 to 30 parts by weight of a thermoplastic polyurethane. Or an elastomer composition comprising 5 to 10 parts by weight of polymethyl methacrylate or ultra high molecular weight polyethylene.

[0007]

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.

[0008] 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, DYNAR manufactured by JSR Corporation
ON HSBR1320P (10% styrene content) and 1910P (30% styrene content) can be used.

The thermoplastic polyurethane may be a commonly used thermoplastic polyurethane. Examples of commercially available products include Elaston ET12 manufactured by Takeda Birdish Co., Ltd.
85 and the like. Polymethyl methacrylate may also be a commonly used polymethyl methacrylate. Ultra-high molecular weight polyethylene is a molecular weight of about 500,000 to 5,
It is a polyethylene of 1,000,000, and commercially available products include, for example, Mitsui Chemicals, Inc., Lübma-L4000.

The amount of the olefin elastomer, hydrogenated styrene-butadiene rubber, and thermoplastic polyurethane, polymethyl methacrylate or ultrahigh molecular weight polyethylene in the composition of the present invention is generally 40 to 85 parts by weight of the olefin elastomer, 10 to 30 parts by weight of styrene-butadiene rubber and 10 to 30 parts by weight of thermoplastic polyurethane or 5 to 10 parts by weight of polymethyl methacrylate or ultra-high molecular weight polyethylene. However, the total weight does not exceed 100 weight parts. Therefore,
When using a thermoplastic polyurethane, the amount of the olefin-based elastomer is 40 to 80 parts by weight, and when using polymethyl methacrylate or ultra-high molecular weight polyethylene, the amount of the olefin-based elastomer is 60 to 85 parts by weight.
It is appropriate to use parts by weight.

When 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. If the amount of the thermoplastic polyurethane, polymethyl methacrylate or ultra-high molecular weight polyethylene exceeds the above upper limit, the flexibility is reduced.

A flame retardant can be added to the composition of the present invention, if desired. 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 (eg,
Magnesium hydroxide, aluminum hydroxide, etc.), phosphate esters, phosphorus compounds and the like. The amount of the flame retardant is olefin-based elastomer, hydrogenated styrene
It is 5 to 200 parts by weight, preferably 60 to 120 parts by weight, per 100 parts by weight of the butadiene rubber and the thermoplastic polyurethane, polymethyl methacrylate or ultrahigh molecular weight polyethylene. Within this range, good flame retardancy can be imparted to the composition.

The composition of the present invention may contain any of the additives usually added to elastomer compositions conventionally used as wire harness component materials and the like. 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. 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 contains thermoplastic polyurethane, polymethyl methacrylate or ultra-high molecular weight polyethylene, the composition can be reduced in thickness without impairing the properties of the conventional olefin-based elastomer composition. Sufficient wear resistance can be maintained. Therefore, the product weight can be reduced as a result.

[0015]

EXAMPLES Examples, comparative examples and reference examples are shown below.
The present invention will be specifically described. Examples 1 and 2, Comparative Example 1 and Reference Example 1 The components shown in Table 1 were used in the amounts shown in Table 1 and kneaded at 170 ° C. for 10 minutes using a pressurized kneader (capacity: 20 liters). And pelletized. 5
Using a 0 mmφ extruder, at a die temperature of 180 ° C. and a linear velocity of 35 m / min, a protective tube for wire harness (thickness 0.24 mm (0.1 in Example 1) was obtained from the obtained pellets.
4 mm) and an inner diameter of 10 mm). When the obtained tube was naturally wound up with a diameter of 400 mm,
The film could be wound well without breaking.
In addition, the natural winding means that the manufactured tube is freely dropped and spirally wound. In addition, 50mmφ
No crushing occurred in the tube manufactured in the example even at the time of cutting with a counter roller feeder. In addition, as a result of performing a wear resistance test on the obtained tube, the product of the example had the same wear resistance as the conventional product of Reference Example 1 having a thick wall.

The wear resistance was tested as follows. 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 brought into contact with the same portion of the tube at 1500 mm.
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 (the tube wears out). In addition, the thickness is reduced from 0.4 mm to 0.1 mm.
"Mass loss" due to a 40% reduction to 24 mm was calculated.

[0017]

[Table 1] The above results are summarized in Table 1.

Examples 3-4 and Comparative Example 2 Example 1 except that the amounts of each component were changed as shown in Table 2.
Tubes were manufactured in the same procedure as in Examples 2 to 2, and the characteristics were evaluated. Table 2 shows the results.

[Table 2]

Examples 5-6 and Comparative Example 3 Example 1 except that the amounts of each component were changed as shown in Table 3.
Tubes were manufactured in the same procedure as in Examples 2 to 2, and the characteristics were evaluated. Table 3 shows the results.

[Table 3]

Examples 7 and 8, Comparative Example 4 and Reference Example 2 The components shown in Table 4 were used in the amounts shown in Table 4 and kneaded at 170 ° C. for 10 minutes using a pressurized kneader (capacity: 20 liters). And pelletized using a pelletizer. 5
Using a 0 mmφ extruder at a die temperature of 180 ° C. and a linear velocity of 35 m / min, a protective tube for wire harness (thickness 0.24 mm (0.1 in Example 2)
4 mm) and an inner diameter of 10 mm). When the obtained tube was subjected to a natural winding treatment in the same manner as in Examples 1 to 6, it was possible to wind the tube without breaking. In addition, even when cutting with a 50 mmφ opposed roller feeding device, no crushing occurred in the tube manufactured in the example. In addition, as a result of performing a wear resistance test (scraping wear test) on the obtained tube, the product of the example had a wear resistance equal to or higher than that of the conventional product of Reference Example 2 having a thick wall. .

The scrape abrasion test was carried out as follows. An iron rod having an outer diameter slightly smaller than the inner diameter of the sample tube is passed through the tube, and the end of the tube is fixed with an adhesive tape. While applying a load of 7.35 N to the jig having the shape of the tip R = 0.2 mm, the tip of the jig is brought into contact with the tip of the jig 50 to 60 times per minute at a stroke width of 10 mm on the surface of the sample tube. Reciprocate. Measure the number of times until the tip of the jig contacts the iron bar. In addition, "mass reduction" due to a 40% reduction in wall thickness from 0.4 mm to 0.24 mm was calculated.

The results are summarized in Table 4.

[Table 4]

Examples 9 to 10 and Comparative Example 5 Example 7 except that the amounts of the components were changed as shown in Table 5.
Tubes were manufactured in the same procedure as in Examples 8 to 8, and their characteristics were evaluated. Table 5 shows the results.

[Table 5]

Examples 11 to 12 and Comparative Example 6 Example 7 except that the amounts of the components were changed as shown in Table 6.
Tubes were manufactured in the same procedure as in Examples 8 to 8, and their characteristics were evaluated. Table 6 shows the results.

[Table 6]

Examples 13 to 14 and Comparative Example 7 The components shown in Table 7 were used in the amounts shown in Table 7, kneaded with a pressurized kneader (capacity: 20 liters) at 170 ° C. for 10 minutes, and then used with a pelletizer. And pelletized. 5
Using a 0 mmφ extruder, a protective tube for wire harness (thickness 0.24 mm, inner diameter 10 mm) 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 natural winding treatment in the same manner as in Examples 1 to 6, it was possible to wind the tube without breaking. In addition, 50mmφ
No crushing occurred in the tube manufactured in the example even at the time of cutting with a counter roller feeder. Further, the obtained tube was subjected to a wear resistance test (scrape wear test) in the same manner as in Examples 7 and 8. Table 7 shows the results.

[0026]

[Table 7]

Examples 15-16 and Comparative Example 8 Example 1 except that the amounts of each component were changed as shown in Table 8.
Tubes were manufactured in the same procedure as in 3 to 14, and the characteristics were evaluated. Table 8 shows the results.

[Table 8]

Examples 17-18 and Comparative Example 9 Example 1 except that the amounts of each component were changed as shown in Table 9.
Tubes were manufactured in the same procedure as in 3 to 14, and the characteristics were evaluated. Table 9 shows the results.

[Table 9]

According to the present invention, the heat resistance is improved by blending a hydrogenated styrene / butadiene rubber which is flexible and excellent in elasticity and a thermoplastic polyurethane or polymethyl methacrylate or ultra high molecular weight polyethylene which is excellent in abrasion resistance into an olefin elastomer. It has excellent workability (winding process after extrusion molding, cut length, assembling wire harness) while maintaining sufficient wear resistance, and has sufficient properties (heat resistance, wear resistance, etc.) as exterior parts. It is possible to provide an elastomer composition suitable for a wire harness exterior protective material which can reduce product weight and does not contain an environmentally harmful halogen element.

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Claims (3)

[Claims] 1 to 40 parts by weight of an olefin elastomer, 10 to 30 parts by weight of a hydrogenated styrene / butadiene rubber, and 10 to 30 parts by weight of a thermoplastic polyurethane or 5 to 10 parts by weight of polymethyl methacrylate or ultrahigh molecular weight polyethylene. An elastomer composition comprising: 2. The elastomer composition according to claim 1, wherein the olefin-based elastomer is a propylene-ethylene-propylene copolymer. 3. A flame retardant is added in an amount of 5 to 2 per 100 parts by weight of a total of olefinic elastomer, hydrogenated styrene / butadiene rubber and thermoplastic polyurethane or polymethyl methacrylate or ultra high molecular weight polyethylene.
The elastomer composition according to claim 1, which comprises 00 parts by weight.