JP3031076B2 - Small-diameter flame-retardant insulated wire - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention has flame retardancy,
The present invention relates to a small-diameter flame-retardant insulated wire having excellent wear resistance and cold resistance.

[0002]

2. Description of the Related Art In recent years, high performance and high functionality of automobiles have been rapidly promoted, mainly for passenger cars, and with this, electric and electronic circuits have increased and the enlargement of wire harnesses has become a problem. This enlargement causes adverse effects such as an increase in wiring space, an increase in weight and cost. For this reason, countermeasures against the enlargement have been demanded, and as a part of this, thinning and thinning of the wire harness electric wire have been studied. It is becoming thinner.

[0003]

[0005] Recently, global environmental protection has been receiving attention as a global issue, and resources and processed products have been recycled and industrial waste has been treated in a wide range of fields such as automobiles. Is gaining importance at the global level. For this reason, the generation of corrosive halogen-based gas at the time of incineration of polyvinyl chloride used for automobile wire harness electric wires has been regarded as a problem of global environmental pollution. From such social trends, attention has been paid to non-halogen flame-retardant materials that generate less corrosive gas. However, non-halogen flame-retardant materials in which a metal hydroxide is mixed with polyolefin have lower toughness than conventional polyvinyl chloride, and particularly have small diameter and poor abrasion resistance.
It was difficult to apply to thin electric wires.

Accordingly, the present invention has been devised in order to effectively solve the above-mentioned problems, and an object of the present invention is to prevent generation of a highly corrosive halogen-based gas at the time of combustion and to achieve high abrasion resistance. The present invention provides a small-diameter flame-retardant insulated wire having the following.

[0005]

In order to achieve the above object, the present invention provides (a) polypropylene having a yield strength of 3.0 kg / mm ² or more, (b) ultra-low density polyethylene or linear low density polyethylene, and (C) It contains a carboxylic acid-modified polymer, and the weight ratio of component (a) / component (b) is 60.
/ 40 to 95/5, [(a) component + (b) component]
/ 100 parts by weight of the blend polymer having a weight ratio of the component (c) of 80/20 to 97/3, and a metal hydroxide 40
The composition is prepared by coating the composition around 100 parts by weight around the conductor.

As the polypropylene, a homopolymer,
Random copolymers, block copolymers, and graft copolymers are listed, and their yield strength is JIS-K675.
In the tensile test of No. 8, it is necessary to be 3.0 kg / mm ² or more, and if it is less than the limit value, the target wear resistance cannot be imparted. However, such polypropylene alone has low elongation and cold resistance, and as a result of various investigations, it has been found that the use of ultra-low-density polyethylene or linear low-density polyethylene in combination, and the addition of a carboxylic acid-modified polymer further reduces the abrasion resistance. It has been found that elongation or cold resistance can be improved without significantly reducing the amount, and the present invention has been accomplished.

Here, ultra-low density polyethylene or linear low density polyethylene is a copolymer of ethylene and α-olefin, the former having a density of 0.910 or less and a melting point peak of 110 to 120 ° C., and the latter having a density of 0. .910-0.
935, with a melting point peak of 115-130 ° C.
The carboxylic acid-modified polymer is obtained by grafting or copolymerizing a carboxylic acid to a polyolefin represented by low-density polyethylene, medium-density polyethylene, high-density polyethylene, and polypropylene-ethylene-vinyl acetate copolymer, and the carboxylic acid is maleic anhydride. Is typical.

The blend ratio of polypropylene to ultra low density polyethylene or linear low density polyethylene is 60 /
The weight ratio is 40 to 95/5, and if the weight ratio is out of the specified range, wear resistance, elongation, and cold resistance cannot be provided. Also,
The weight ratio of the blend polymer to the carboxylic acid-modified polymer is preferably from 80/20 to 97/3. If the ratio of the carboxylic acid-modified polymer exceeds the limit value, the elongation is remarkably reduced. No effect is observed.

Examples of the metal hydroxide include magnesium hydroxide, aluminum hydroxide, hydrotalcites and the like, and magnesium hydroxide is particularly preferred from the viewpoint of flame retardancy. It is preferable to use those having an average particle diameter of 0.1 to 5 μm and surface-treated with a fatty acid, a fatty acid metal salt, a silane coupling agent, a titanate coupling agent, or the like from the viewpoints of aggregation, toughness, flame retardancy, and water resistance. .

The blending amount of the metal hydroxide is as follows: a blend polymer of polypropylene and ultra-low-density polyethylene or linear low-density polyethylene, and a carboxylic acid-modified polymer.
The amount must be 0 parts by weight. If the amount is less than the limit value, the desired flame retardancy cannot be imparted. If the amount exceeds the limit value, the wear resistance is significantly impaired.

In the present invention, a polyfunctional monomer, an antioxidant, a copper damage inhibitor and the like may be appropriately added to the above-mentioned components, and a composition comprising the composition may be irradiated with an electron beam or the like.

[0012]

Since the present invention has the above-described composition, it is possible to manufacture a thin-diameter, thin-walled electric wire having excellent flame resistance, abrasion resistance, and cold resistance. Will not occur.

[0013]

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

First, various components were kneaded in a 30 mm twin-screw kneader set at 220 ° C. in accordance with the components shown in each column of Examples and Comparative Examples 1 to 6 in Table 1, and these were then mixed with 220
It was extrusion-coated with a thickness of 0.35 mm on a copper conductor having a core wire outer diameter of 0.87φ using a 40 mm extruder set at ° C. At this time, the conductor was preheated to 130 ° C. with a gas burner.

Next, the electric wires thus manufactured were evaluated as described below.

(1) Flame retardancy Based on Japanese Automobile Standards (JASO) D608-87,
A 300 mm sample was supported horizontally, and the residual flame time after applying a Bunsen burner reducing flame for 10 seconds was measured. And
A residual flame time of 30 seconds or less was judged as pass, and a flame time of more than 30 seconds was judged as unacceptable.

(2) Wear Resistance According to JASO-D608-87, a wear test was performed four times by a reciprocating method using a blade with a load of 510 g, and the minimum number of conductor exposures was shown.

(3) Tensile Properties Using a tubular test piece from which the conductor was removed, measurement was performed at a temperature of 23 ° C. and a tensile speed of 200 mm / min.

(4) Cold resistance According to JIS-C3406-6,7, after holding the electric wire at -40 ° C for 3 hours, the wire is placed in a 75φ cylinder at this temperature.
Bend 0 °. Thereafter, a withstand voltage test was performed in water at 1000 V for 1 minute.

[0020]

[Table 1]

As a result, as shown in Table 1, it is understood that each of the samples of Examples 1 to 5 according to the present invention has good flame retardancy, tensile properties, cold resistance, and excellent wear resistance.

On the other hand, in Comparative Example 1 in which the yield strength of the polypropylene was less than the specified value, and in Comparative Example 2 in which the blend ratio of the polypropylene and the ultra-low density polyethylene was out of the specified range, the abrasion resistance was significantly reduced. In Comparative Example 3 using polyethylene other than ultra-low-density polyethylene or linear low-density polyethylene, the decrease in elongation was large and the cold resistance was also low. In Comparative Example 4 in which the polyethylene was not blended and in Comparative Example 5 in which the carboxylic acid-modified polymer was not added, the cold resistance was poor. Furthermore, in Comparative Example 6 in which the amount of the metal hydroxide mixed exceeds the limit value, the wear resistance and the cold resistance are significantly reduced.

[0023]

As described in detail above, according to the present invention, it is possible to manufacture a thin-diameter, thin-walled electric wire having excellent flame resistance, abrasion resistance, and cold resistance, and at the same time, a halogen-based halogen-based material having high corrosion resistance. It has excellent effects such as not generating gas and greatly reducing environmental pollution.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ identification code FI C08L 23/10 C08L 23/10 H01B 7/18 H01B 7/18 B (58) Investigated field (Int.Cl. ⁷ , DB name ) H01B 7/18-7/36 H01B 3/00-3/44

Claims (1)

(57) [Claims] 1. Component (a) comprising (a) polypropylene having a yield strength of at least 3.0 kg / mm ² , (b) ultra-low density polyethylene or linear low-density polyethylene, and (c) a carboxylic acid-modified polymer. / The weight ratio of the component (b) is 6
0/40 to 95/5, and 100 parts by weight of the blend polymer in which the weight ratio of the component (a) + the component (b) / the component (c) is 80/20 to 97/3, A small-diameter flame-retardant insulated wire, characterized in that a composition containing 40 to 100 parts by weight of an oxide is coated around a conductor.