JPH0676644A - Thin-walled flame-retardant insulated wire - Google Patents

Abstract

PURPOSE:To provide a new thin-walled flame-retardant insulated wire which does not generate any highly corrosive halogen gas during combustion and has high abrasion resistance. CONSTITUTION:A composition contains (a) a polyolefin having a yield strength of 3.0Kg/mm<2> or more and (b) an extra molecular-weight polyethylene having an average molecular weight of 1X10<6> or more and an average particle size of 50mum or less. A conductor is covered at its periphery with the composition having 40 to 100 parts by weight of a metal hydroxide blended with 100 parts by weight of the blended polymers comprising (a), (b) components blended in a weight ratio of 95:5 to 70:30.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flame-retardant thin-wall flame-retardant insulated wire having excellent wear resistance.

[0002]

2. Description of the Related Art In recent years, the performance and functionality of automobiles, especially passenger cars, have been rapidly advanced, and along with this, the number of electric and electronic circuits has increased and the enlargement of wire harness has become a problem. Since this enlargement causes adverse effects such as an increase in wiring space, weight and cost, countermeasures against enlargement have been demanded, and as a part of this, reduction in diameter and thinning of wire harness electric wires has been studied. In the case of polyvinyl chloride insulated wires, the core diameter and insulation diameter are reduced to reduce the diameter,
Thinning has come to be achieved.

[0003]

By the way, recently, the preservation of the global environment has been attracting attention as a global issue, and recycling of resources and processed products and industrial waste treatment in a wide range of fields represented by automobiles. Has come to be regarded as important at the global level. Therefore, even for polyvinyl chloride used for wire harnesses for automobiles, the generation of corrosive halogen-based gas during incineration is becoming a problem as global environmental pollution. From such social trends, attention has been paid to non-halogen flame-retardant materials that do not generate corrosive gas.

However, a non-halogen flame-retardant material in which a metal hydroxide is mixed with a polyolefin is inferior in toughness as compared with conventional polyvinyl chloride, and particularly in abrasion resistance,
It was difficult to apply to thin and thin electric wires.

Therefore, the present invention has been devised in order to effectively solve the above-mentioned problems, and its purpose is not to generate a halogen-based gas having a high corrosiveness at the time of combustion and to have a high wear resistance. A thin flame-retardant insulated electric wire having

[0006]

In order to achieve the above object, the present invention provides (a) a polyolefin having a yield strength of 3.0 kg / mm ² or more, and (b) an average molecular weight of 1 × 10 ⁶ or more and an average particle diameter of 50 μm. The following ultra high molecular weight polyethylene is contained, and the weight ratio of component (a) / component (b) is 95/5 to 70.
A composition in which 40 to 100 parts by weight of a metal hydroxide is mixed with 100 parts by weight of a blend polymer of / 30 is coated around the conductor.

In the present invention, examples of the polyolefin include polypropylene and high-density polyethylene, which are required to have a yield strength of 3.0 Kg / mm ² or more in a tensile test according to JIS-K-6758. The target wear resistance cannot be imparted. Examples of polypropylene include homopolymers, random copolymers, block copolymers, and graft copolymers. Further, as high-density polyethylene, the density at 23 ° C. is 0.9.
Forty-five or more polyethylene is referred to herein. And by dispersing ultra high molecular weight polyethylene in these,
The inventors have found that the wear resistance is remarkably improved and have reached the present invention.

The ultra-high molecular weight polyethylene is a polyethylene having a viscosity average molecular weight of 1 × 10 ⁶ or more, and the average particle diameter thereof must be 50 μm or less. That is, if the average particle diameter exceeds the limited value, the desired effect of improving the wear resistance is significantly reduced. Further, the blending ratio of the above-mentioned polyolefin and ultra high molecular weight polyethylene needs to be 95/5 to 70/30 by weight ratio, and if the ratio of the ultra high molecular weight polyethylene is less than the limited value, the target abrasion resistance can be imparted. On the other hand, if the limit value is exceeded, extrusion molding becomes difficult.

Magnesium hydroxide, which has a high decomposition temperature, is desirable as the metal hydroxide, and it has a mean particle size of 0.1 to 5 μm and a fatty acid metal salt or silane because of its aggregation, toughness, flame retardancy, water resistance and the like. It is preferable to use those surface-treated with a coupling agent, a titanate coupling agent, or the like.
The amount of the metal hydroxide to be blended must be 40 to 100 parts by weight of the metal hydroxide based on 100 parts by weight of the blended polymer which is a combination of the above-mentioned polyolefin and ultra-high molecular weight polyethylene. If it is less than the limit value, the desired flame retardancy cannot be imparted, and if it exceeds the limit value, the wear resistance is significantly reduced.

Further, in the present invention, in addition to the above-mentioned components, a polyfunctional monomer, an antioxidant, a copper damage inhibitor, etc. may be appropriately added, and the insulating composition composed of this may be subjected to electron beam irradiation or the like. .

[0011]

Since the present invention has the above-described structure, it is possible to manufacture a small-diameter, thin-walled electric wire that is flame-retardant and has excellent wear resistance, and does not generate a halogen-based gas that is highly corrosive when incinerated. , Does not cause environmental pollution.

[0012]

EXAMPLE An example of the present invention will be described in detail below.

According to the blending components shown in the columns of Examples 1 to 5 and Comparative Examples 1 to 5 in Table 1, each main component was kneaded with a 30 mm biaxial kneader set to 220 ° C.
Using a 40 mm extruder set at 0 ° C., a copper conductor having a core wire outer diameter of 0.87φ was extrusion-coated with a thickness of 0.20 mm. At this time, the conductor was preheated to 100 ° C. with a gas burner. In Example 5, electron beam crosslinking was performed at 20 Mrad.
The electric wires thus produced were evaluated as follows.

(1) Flame retardance According to Japanese Automotive Standard (JASO) D608-87,
The sample after 300 mm was supported horizontally, and the afterflame time after applying the reducing flame of Bunsen burner for 10 seconds passed within 30 seconds,
Those over 30 seconds were judged as rejected.

(2) Wear resistance According to JASO-D608-87, a wear test by a blade reciprocating method was carried out four times under a load of 510 g to show the minimum number of conductor exposures.

(3) Self-diameter winding test: A mandrel having an outer diameter of 1.27φ was wound at room temperature for 6 turns, and the occurrence of cracks was examined. Those with no cracks were judged to be acceptable, and those with cracks were judged to be unacceptable.

[0017]

[Table 1]

As a result, as is clear from Table 1, all the samples of Examples 1 to 5 of the present invention passed the flame retardancy test, did not cause cracks in the self-diameter winding test, and were excellent. It can be seen that it has abrasion resistance. On the other hand, in Comparative Example 1 in which ultra-high molecular weight polyethylene is not added, abrasion resistance is remarkably poor, and in Comparative Example 2 in which the ratio of ultra-high molecular weight polyethylene exceeds the limit value, extrusion molding is difficult. further,
In Comparative Example 3 using a polymer whose yield strength of polyolefin is less than the specified value and Comparative Example 4 using ultra-high density polyethylene whose average particle size exceeds the specified value, wear resistance is low, and the latter is self-wrapping. The test causes cracks. Also,
Comparative Example 5 in which the mixing amount of magnesium hydroxide exceeds the limit value
Wear resistance remarkably decreases.

[0019]

As described above in detail, according to the present invention, it is possible to manufacture a small-diameter, thin-walled electric wire which is flame-retardant and has excellent wear resistance, and moreover, it produces a halogen gas which is highly corrosive when incinerated. Without doing so, it has an excellent effect that environmental pollution can be greatly reduced.

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Claims (1)

[Claims] 1. A component containing (a) a polyolefin having a yield strength of 3.0 kg / mm ² or more and (b) an ultrahigh molecular weight polyethylene having an average molecular weight of 1 × 10 ⁶ or more and an average particle size of 50 μm or less, The weight ratio of the component (b) is 95/5 to 7
With respect to 100 parts by weight of the blend polymer which is 0/30,
A thin flame-retardant insulated electric wire, characterized in that the conductor is coated with a composition containing 40 to 100 parts by weight of a metal hydroxide.