JP2002128963A - Polyolefin resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide polyolefin resin compositions which have excellent wear resistance, sufficiently high flame retardancy and, in addition, are useful as protective tubes for the lightweight wire harness electric wire for automobiles and sheet materials. SOLUTION: The polyolefin compositions comprise 10-99 pts.wt. hard polyolefin resin and 1-90 pts.wt. ethylene-propylene copolymer rubber or ethylene- butene-1 copolymer and, if necessary, based on 100 pts.wt. sum of the polyolefin resin and the ethylene-propylene copolymer rubber or ethylene-butene-1 copolymer, at least 2 pts.wt. bromine based flame-retardant (in terms of the bromine element) and at least 1 pt.wt. antimony trioxide, and at least 0.2 wt.% lubricant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyolefin resin composition, and more particularly to a polyolefin resin composition useful as a material for protective tubes and sheets of electric wires used in automobile wire harnesses.

[0002]

2. Description of the Related Art Protective tubes and sheets for automobile wire harness electric wires have hitherto been mainly formed of polyvinyl chloride. However, in consideration of recent global environmental measures, halogen-free materials have been used in place of polyvinyl chloride in the production of automotive wiring harness component materials, such as tubes and sheets.
Conventional halogen-free materials focus on heat resistance and abrasion resistance, and use olefin-based elastomers such as propylene-based elastomers.
A composition in which a metal hydroxide is added as a flame retardant to an ethylene-propylene copolymer, and a fatty acid salt or the like is further added as a lubricant is used.

[0003] On the other hand, in recent years, increasingly high flame retardancy has been required for protective materials for wire harness wires for automobiles. However, in the composition containing the above-mentioned olefin-based elastomer and metal hydroxide, The required flame retardancy cannot be satisfied. In addition, as part of environmental measures, it has been proposed to reduce the weight of automobiles to improve fuel efficiency. For that purpose, it is also important to reduce the weight of components such as wire harnesses. However, the specific gravity of the composition containing polyvinyl chloride or an olefin-based elastomer and a metal hydroxide is 1.3 or more, which hinders weight reduction. However, in the conventional materials, when the thickness of the tube or the like is reduced to reduce the weight, the wear resistance is greatly reduced, and the function as the outer tube or the like cannot be performed.

[0004]

DISCLOSURE OF THE INVENTION The present invention is useful as a protective tube and sheet material for a wire harness electric wire for an automobile, which can realize light weight and low halogen without deteriorating wear resistance and other required characteristics. It is intended to provide a polyolefin resin composition.

[0005]

In order to solve the above-mentioned problems, the present invention provides a hard polyolefin resin of 10 to 99 parts by weight and an ethylene-propylene copolymer rubber or an ethylene-butene-1 copolymer of 1 to 90 parts by weight. Parts, optionally at least 2 parts by weight of a brominated flame retardant (in terms of elemental bromine weight), based on 100 parts by weight of the total of the hard polyolefin resin and the ethylene-propylene copolymer rubber or ethylene-butene-1 copolymer. A polyolefin resin composition further comprising at least 1 part by weight of antimony trioxide and at least 0.2% 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, the hard polyolefin resin has an olefin as a main component (that is, 50% by weight or more of a repeating unit) and a flexural modulus of 700 MPa.
a or higher polyolefin resin. 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 polyolefin resin may be a homopolymer or a copolymer, and the type of the copolymer is not limited, but polyethylene and polypropylene are preferred. Polyethylene is high density polyethylene (HDP
E), low density polyethylene (LDPE) and linear low density polyethylene (LLDPE). Commercial products include Mitsui Chemicals Hizex 5305E (polyethylene) and Tokuyama RB110 (polypropylene).

[0007] The ethylene-propylene copolymer rubber may be one conventionally used. The composition ratio of ethylene and propylene is as follows: ethylene: propylene = 50: 5
0 to 80:20, preferably 65:35 to 75:25
(Weight ratio). As a commercially available product, EP02 manufactured by JSR
P and the like. The ethylene-butene-1 copolymer may also be those conventionally used. Commercially available products include X-75 manufactured by Mitsui Chemicals.

[0008] The ratio of the polyolefin resin contained in the composition is 1 in total of the polyolefin resin and the ethylene-propylene copolymer rubber or ethylene-butene-1 copolymer.
10 to 99 parts by weight, preferably 4 parts by weight, per 100 parts by weight
0 to 90 parts by weight. Therefore, the proportion of the ethylene-propylene copolymer rubber is 1 to 90 parts by weight, preferably 10 to 60 parts by weight, based on 100 parts by weight of the total of the polyolefin resin and the ethylene-propylene copolymer rubber. However, when using an ethylene-propylene copolymer rubber, the upper limit of the amount is preferably set to 80 parts by weight.

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: 68% by weight) manufactured by Teijin Chemicals Limited and Flame Cut 1 manufactured by Tosoh Corporation.
21R (bromine element content: 67% by weight).

The amount of the brominated flame retardant is based on 100 parts by weight of the total of the polyolefin resin and the ethylene-propylene copolymer rubber or the ethylene-butene-1 copolymer.
It is at least 2 parts by weight (in terms of elemental bromine weight), preferably at least 2.5 parts 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. Therefore, a preferred upper limit is 15% by weight.

The amount of antimony trioxide is at least 1 part by weight, preferably at least 2.5 parts by weight, per 100 parts by weight of the total of polyolefin resin and ethylene-propylene copolymer rubber or ethylene-butene-1 copolymer.
Parts by weight. If the amount of antimony trioxide is less than 1 part by weight, sufficient flame retardancy cannot be imparted. The upper limit is not particularly limited, but if there is too much antimony trioxide,
The specific gravity of the composition increases.

[0012] The polyolefin resin composition of the present invention includes:
A lubricant is blended to improve moldability. Examples of the lubricant include fatty acids, fatty acid metal salts, and fatty acid amides. The blending amount of the lubricant may be a polyolefin resin and an ethylene-propylene copolymer rubber or an ethylene-propylene rubber.
It is at least 0.2 part by weight, preferably 0.5 part by weight, based on 100 parts by weight of the butene-1 copolymer in total.

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 various colorants, antistatic agents and the like. The amount of the additive may be appropriately selected according to the type of the additive.

[0014] The polyolefin resin is a relatively hard resin, but the composition is flexible because it contains a low modulus ethylene-propylene copolymer rubber or ethylene-butene-1 copolymer. Further, the polyolefin resin and the ethylene-propylene copolymer rubber or the ethylene-butene-1 copolymer both have good abrasion resistance and good compatibility with each other, so that the blend can be made without impairing the mechanical properties of the composition. can do.

In the present invention, a polyolefin resin composition having high flame retardancy can be obtained without impairing the properties of the polyolefin resin by adding a bromine-based flame retardant capable of imparting high flame retardancy to the polyolefin resin in a small amount. Can be The halogen content (by weight) of the composition of the present invention is about 1/10 or less as compared with polyvinyl chloride.

[0016]

Examples 1 to 5 Using a pressure kneader (volume: 10 liters), the components shown in Tables 1 and 2 were kneaded at 170 ° C. for 10 minutes and pelletized with a pelletizer. The amounts of the components in the table are "parts by weight". Using these pellets, diameter 50m
m, a die temperature of 200 ° C. and a linear speed of 35 m /
In a minute, it was extruded to obtain a tube having a thickness of 0.3 mm and an inner diameter of 10 mm.

The resulting tubes were tested for tensile strength, flame retardancy and abrasion resistance by the following methods. Tensile strength The tensile strength at break was measured based on the tensile test of JIS K6310. Flame retardancy According to JIS K 7201, the oxygen index (OI) was measured to evaluate the flame retardancy. Abrasion resistance (scraping test) : Using the blade (hardened steel) shown in FIG. 1, the blade was pressed against the sample with a load of 7.4 N as shown in FIG. 2, and the amplitude was 10 m at a temperature of 23 ° C.
Reciprocate once per second with m. The number of round trips until the sample is completely worn and disappears is recorded. 2000 or more passes. The results are shown in Tables 1 and 2. In addition, the tubes manufactured in Examples 1 to 10 were also subjected to tests such as aging characteristics, heat resistance, cold resistance, and hardness, and all of them had sufficient characteristics as tube materials.

Comparative Example 1 Using a polyvinyl chloride tube having a thickness of 0.5 mm and an inner diameter of 10 mm, tensile strength, flame retardancy and abrasion resistance were tested by the following methods in the same manner as in the example. Table 1 shows the results.

[0019]

[Table 1]

[0020]

[Table 2]

Note: 1) HIZEX 5305 manufactured by Mitsui Chemicals, Inc.
E. 2) Tokuyama RB110. 3) Ethylene-propylene copolymer EP02 manufactured by JSR
P. 4) Fire Guard 3100 manufactured by Teijin Chemicals Limited (bromine content: 68% by weight). 5) Mikuni Refining Co., Ltd. 6) Made by Sakai Chemical Co., Ltd. 7) Assuming that the weight of halogen contained in the PVC tube of Comparative Example 1 is 100, the amount of halogen contained in the tubes manufactured in each Example having the same length. 8) Weight ratio when PVC of the same volume is set to 100. 9) Mitsui Chemicals ethylene-butene-1 copolymer X-7
5

[Brief description of the drawings]

FIG. 1 is a schematic view of a blade used in a scrape test.

FIG. 2 is a diagram showing an arrangement of a blade and a sample in a scrape test.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 23/16 C08L 23/16 H01B 7/00 301 H01B 7/00 301 7/18 7/18 B 7 / 295 7/34 BF term (reference) 4J002 BB01W BB03W BB05X BB12W BB15X DE127 EF018 EG018 EJ056 EP008 FD136 FD137 FD178 5G309 AA11 5G313 AB03 AB09 AD08 AE01 AE02 AE07 5G315 CA03 CC04 CD08 CC08

Claims (5)

[Claims] 1. A polyolefin resin composition comprising 10 to 99 parts by weight of a hard polyolefin resin and 1 to 90 parts by weight of an ethylene-propylene copolymer rubber or an ethylene-butene-1 copolymer. 2. The polyolefin resin composition according to claim 1, comprising 40 to 90 parts by weight of a hard polyolefin resin and 10 to 60 parts by weight of an ethylene-propylene copolymer rubber or an ethylene-butene-1 copolymer. 3. The polyolefin resin composition according to claim 1, wherein the polyolefin resin is polyethylene or polypropylene. 4. A brominated flame retardant (in terms of elemental bromine weight) of at least 2 parts by weight, based on 100 parts by weight of the total of the polyolefin resin and the ethylene-propylene copolymer rubber or ethylene-butene-1 copolymer. At least 1 part by weight of antimony oxide and at least 0.2% by weight of a lubricant
The polyolefin resin composition according to claim 1, further comprising: 5. The polyolefin resin composition according to claim 4, wherein the lubricant is a fatty acid salt.