JPH10334738A - Wire/cable covered with elastomer containing fluorine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the tensile strength and elongation and improve the dielectric breakdown voltage and thermal aging resistance by mixing calcium carbonate having a specified particle size to a fluorine polymer composition for covering a conductor or insulated wire core periphery. SOLUTION: An insulated wire core 3 formed by stranding two crosslinked polyethylene insulated wires covered with crosslinked polyethylene are provided on a copper stranded wire 1, and the periphery is covered with a fluorine polymer composition. It is passed in an ionizing radiation irradiating reactor, and crosslinked by irradiating electron beams, whereby a fluorine-containing elastomer covered wire or cable is provided. In this case, the fluorine polymer composition is obtained by mixing calcium carbonate having a particle size of 0.5 μm or less to fluorine polymer. Thus, the initial tensile strength and elongation are enhanced, the tensile strength and elongation after thermal aging are enhance, and the dielectric breakdown voltage can be also increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorine-containing elastomer-coated electric wire / cable.

[0002]

2. Description of the Related Art Various rubbers and plastics are used as covering materials for electric wires and cables.

[0003] Rubber coating materials include natural rubber, chloroprene rubber, styrene butadiene rubber, chlorosulfonated polypolyethylene rubber, ethylene propylene diene rubber, polyurethane rubber, silicone rubber, fluorine rubber, and tetrafluoroethylene-propylene copolymer. .

As plastics coating materials, polyethylene, polypropylene, polyvinyl chloride admixture,
There are polyamide resin, fluorine resin and the like.

Among these, tetrafluoroethylene-propylene copolymers are excellent in flexibility, heat resistance, heat stability, electrical insulation, oil resistance, chemical resistance, flame retardancy, etc. -It has come to be widely used as a heat-resistant coating material for cables. In particular, a tetrafluoroethylene-propylene copolymer elastomer crosslinked by heat or radiation irradiation using peroxide is used for electric wires and
It is widely used as a heat-resistant coating material for cables.

However, since the tetrafluoroethylene-propylene copolymer also has plastic properties on one side, there is a problem that it is easily softened at high temperatures.
In particular, an electric wire formed by thinly coating a tetrafluoroethylene-propylene copolymer on a conductor or an outer periphery of an electric wire core.
Because the cable is thin, it is extremely susceptible to thermal softening at high temperatures.

[0007] The characteristic that it is difficult to thermally soften at such a high temperature is
It is evaluated for cut-through resistance. Although the details of this test method will be described later, the point is that a blade with a load is placed on the surface of the test material at a high temperature and the cut-through state is evaluated.

Hitherto, as a method for improving the cut-through resistance of a tetrafluoroethylene-propylene copolymer, a large amount of an inorganic filler has been used. Tetrafluoroethylene containing a large amount of such an inorganic filler
Propylene copolymer improves cut-through resistance,
There is a drawback that tensile strength, elongation, dielectric breakdown voltage, heat aging resistance, etc. are significantly reduced.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of such a point, and an object of the present invention is to solve the above-mentioned disadvantages of the prior art and to provide a remarkably excellent cut-through resistance. An object of the present invention is to provide a fluorine-containing elastomer-coated electric wire / cable which has excellent tensile strength, tensile strength, elongation, dielectric breakdown voltage, heat aging resistance and the like.

[0010]

The gist of the present invention is to provide a fluorine-containing elastomer-coated electric wire or cable comprising a conductor or an outer periphery of an insulated electric wire core coated with a fluoropolymer composition. The composition is a fluorine-containing elastomer-coated electric wire / cable characterized in that the composition is obtained by mixing calcium carbonate having a particle size of 0.5 μm or less with a fluoropolymer.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the invention of a fluorine-containing elastomer-coated electric wire / cable of the present invention will be described.

In the present invention, the fluoropolymer may be a tetrafluoroethylene-propylene copolymer, an ethylene-tetrafluoroethylene copolymer, or a tetrafluoroethylene-propylene copolymer having excellent heat resistance and flexibility. It is a blended fluorine polymer with an ethylene-tetrafluoroethylene copolymer.

Here, the blended fluoropolymer of the tetrafluoroethylene-propylene copolymer and the ethylene-tetrafluoroethylene copolymer does not limit the blend ratio, but from the viewpoint of the property balance, the tetrafluoroethylene-propylene copolymer is not preferred. A propylene copolymer and an ethylene-tetrafluoroethylene copolymer are mixed at a weight ratio of 95 /
A blend of 5-60 / 40 is suitable.

In the present invention, calcium carbonate was used as a filler because heat resistance does not decrease even if calcium carbonate is blended in a large amount in a fluoropolymer.

The calcium carbonate may be surface-treated with a fatty acid, a metal salt of a fatty acid, a silane compound, a titanium compound or the like.

The reason why the particle size is limited to 0.5 μm or less is that, in a fluorine-based polymer composition in which calcium carbonate having a particle size of 0.5 μm or more is blended with a fluoropolymer, the calcium carbonate blended has a coagulated diameter. This is because large secondary agglomerates such as 10 to 30 μm are formed, and as a result, the electrical characteristics of the fluorine-based polymer composition, particularly the dielectric breakdown voltage, are significantly reduced. Here, the dispersibility of the fluoropolymer composition can be easily observed with a scanning electron microscope.

In the present invention, the fluoropolymer composition is obtained by mixing 20 to 100 parts by weight of calcium carbonate having a particle size of 0.5 μm or less with 100 parts by weight of the fluoropolymer.

The reason why the content of calcium carbonate is limited to 20 to 100 parts by weight in the present invention is that when the amount is less than 20 parts by weight, there is no effect of improving the cut-through resistance, and when it is more than 100 parts by weight, the heat resistance sharply decreases. It is. In addition, a more preferable range is 30 to 80 parts by weight.

In the present invention, if necessary, other components such as a crosslinking monomer, a crosslinking agent, a crosslinking aid, a pigment, a lubricant, a processing aid, a stabilizer, an antioxidant and the like may be added in addition to these components. Good.

[0020]

Next, examples of the fluorine-containing elastomer-coated electric wires and cables of the present invention will be described together with comparative examples.

Example 1 First, 90 parts by weight of a tetrafluoroethylene-propylene copolymer having a number average molecular weight of 100,000, a softening point of 225 ° C. and a melt index of 3
0 to 10 parts by weight of ethylene to tetrafluoroethylene-1,1-dihydroperfluoropropene-1, 1 part by weight of triallyl isocyanurate as a cross-linking aid, 1 part by weight of barium stearate as a lubricant, and granules as a filler. Diameter 0.1
60 parts by weight of 5 μm calcium stearate surface-treated calcium carbonate “A” was weighed and collected.

Next, these were uniformly kneaded with a kneading roll at 50 to 60 ° C. to obtain a fluoropolymer composition of Example 1.

Next, the fluoropolymer composition of Example 1 obtained above was heated at a cylinder head temperature of 250 ° C., a cylinder 1 position temperature of 280 ° C., a cylinder 2 position temperature of 300 ° C., and L / D = 22. It was placed in the hopper of a 40 mm extruder.

Next, an insulated wire core was prepared by twisting two cross-linked polyethylene insulated wires each formed by coating a cross-linked polyethylene on a copper stranded wire having a conductor cross-sectional area of 75 mm ^2. Example 1 was obtained by extrusion-coating the fluoropolymer composition of Example 1 to a coating thickness of 1.0 mm.
Of non-crosslinked fluorine-containing elastomer-coated electric wires and cables.

Next, the obtained uncrosslinked fluorine-containing elastomer-coated electric wire / cable of Example 1 is passed through an ionizing radiation irradiation furnace, irradiated with a 10 Mrad electron beam, and crosslinked to obtain the fluorine-containing fluorine-containing material of Example 1. Elastomer-coated wires and cables were obtained.

FIG. 1 shows a cross section of the thus obtained fluorine-containing elastomer-coated electric wire / cable of Example 1.

In FIG. 1, 1 is a copper stranded wire, 2 is a crosslinked polyethylene insulated layer, 3 is a crosslinked polyethylene insulated wire core, 4 is an inclusion layer, and 5 is a fluorine-containing elastomer coating layer.

Although the crosslinked polyethylene is used as the insulating layer here, it is a matter of course that other insulating layers such as a fluorine-containing elastomer, a vinyl chloride resin admixture, various rubbers and the like may be used.

Example 2 First, 90 parts by weight of a tetrafluoroethylene-propylene copolymer having a number average molecular weight of 100,000, a softening point of 225 ° C. and a melt index of 3
0 to 10 parts by weight of ethylene to tetrafluoroethylene-1,1-dihydroperfluoropropene-1, 1 part by weight of a cross-linking aid, triallyl isocyanurate, 1 part by weight of barium stearate as a lubricant, and granules as a filler. Diameter 0.1
80 μm of each of the μm calcium stearate-treated calcium carbonate “B” was weighed and collected.

Thereafter, an uncrosslinked fluorine-containing elastomer-coated electric wire / cable of Example 2 was obtained in the same manner as in Example 1.

Example 3 First, 70 parts by weight of a tetrafluoroethylene-propylene copolymer having a number average molecular weight of 100,000, a softening point of 225 ° C. and a melt index of 3
0 to 30 parts by weight of ethylene to tetrafluoroethylene-1,1-dihydroperfluoropropene-1, 1 part by weight of triallyl isocyanurate as a cross-linking aid, 1 part by weight of barium stearate as a lubricant, and granules as a filler. Diameter 0.1
40 parts by weight of the silica surface-treated calcium carbonate "B" of calcium stearate-treated calcium carbonate "B" having a thickness of μm were weighed and collected.

Thereafter, an uncrosslinked fluorine-containing elastomer-coated electric wire / cable of Example 3 was obtained in the same manner as in Example 1.

Example 4 First, 85 parts by weight of a tetrafluoroethylene-propylene copolymer having a number average molecular weight of 100,000, a softening point of 225 ° C. and a melt index of 3
0 to 15 parts by weight of ethylene to tetrafluoroethylene-1,1-dihydroperfluoropropene-1, 1 part by weight of triallyl isocyanurate as a crosslinking aid, 1 part by weight of barium stearate as a lubricant, and granules as filler. Diameter 0.4
60 parts by weight of 5 μm calcium stearate surface-treated calcium carbonate “C” was weighed and collected.

Thereafter, an uncrosslinked fluorine-containing elastomer-coated electric wire / cable of Example 4 was obtained in the same manner as in Example 1.

Example 5 First, 80 parts by weight of a tetrafluoroethylene-propylene copolymer having a number average molecular weight of 100,000, a softening point of 225 ° C. and a melt index of 3
0 to 20 parts by weight of ethylene to tetrafluoroethylene-1,1-dihydroperfluoropropene-1, 1 part by weight of triallyl isocyanurate as a cross-linking aid, 1 part by weight of barium stearate as a lubricant, and granules as a filler. Diameter 0.1
50 parts by weight of μm calcium stearate surface-treated calcium carbonate “B” were weighed and collected.

Thereafter, an uncrosslinked fluorine-containing elastomer-coated electric wire / cable of Example 5 was obtained in the same manner as in Example 1.

Comparative Example 1 First, a tetrafluoroethylene-propylene copolymer 100 having a number average molecular weight of 100,000 was used.
1 part by weight of triallyl isocyanurate as a cross-linking aid, 1 part by weight of barium stearate as a lubricant, and 80 parts by weight of calcium stearate surface-treated calcium carbonate “D” having a particle size of 1.8 μm as a filler. Weighing,
Collected.

Thereafter, in the same manner as in Example 1, an uncrosslinked fluorine-containing elastomer-coated electric wire / cable of Comparative Example 1 was obtained.

Comparative Example 2 First, 80 parts by weight of a tetrafluoroethylene-propylene copolymer having a number average molecular weight of 100,000, a softening point of 225 ° C. and a melt index of 3
0 to 20 parts by weight of ethylene to tetrafluoroethylene-1,1-dihydroperfluoropropene-1, 1 part by weight of triallyl isocyanurate as a cross-linking aid, 1 part by weight of barium stearate as a lubricant, and granules as a filler. Diameter 0.4
120 parts by weight of 5 μm calcium stearate surface-treated calcium carbonate “C” was weighed and collected.

Thereafter, in the same manner as in Example 1, an uncrosslinked fluorine-containing elastomer-coated electric wire / cable of Comparative Example 2 was obtained.

Comparative Example 3 First, 80 parts by weight of a tetrafluoroethylene-propylene copolymer having a number average molecular weight of 100,000, a softening point of 225 ° C. and a melt index of 3
0 to 30 parts by weight of ethylene to tetrafluoroethylene-1,1-dihydroperfluoropropene-1, 1 part by weight of triallyl isocyanurate as a cross-linking aid, 1 part by weight of barium stearate as a lubricant, and granules as a filler. Diameter 0.1
10 parts by weight of μm calcium stearate surface-treated calcium carbonate “B” was weighed and collected.

Next, these were uniformly kneaded with a kneading roll at 50 to 60 ° C. to obtain a fluoropolymer composition of Example 1.

Thereafter, in the same manner as in Example 1, an uncrosslinked fluorine-containing elastomer-coated electric wire / cable of Comparative Example 3 was obtained.

Comparative Example 4 First, 50 parts by weight of a tetrafluoroethylene-propylene copolymer having a number average molecular weight of 100,000, a softening point of 225 ° C. and a melt index of 3
0 to 50 parts by weight of ethylene to tetrafluoroethylene-1,1-dihydroperfluoropropene-1, 1 part by weight of triallyl isocyanurate as a cross-linking aid, 1 part by weight of barium stearate as a lubricant, and granules as a filler. Diameter 0.1
80 parts by weight of 5 μm calcium stearate surface-treated calcium carbonate “A” was weighed and collected.

Next, these were uniformly kneaded with a kneading roll at 50 to 60 ° C. to obtain a fluoropolymer composition of Example 1.

Thereafter, an uncrosslinked fluorine-containing elastomer-coated electric wire / cable of Comparative Example 4 was obtained in the same manner as in Example 1.

(List of Fluoropolymer Compositions) Table 1 is a list of the fluoropolymer compositions of Examples 1 to 5 and Comparative Examples 1 to 4.

[0048]

[Table 1]

(Method of Testing Properties of Fluorine-Containing Elastomer-Coated Wires and Cables) Next, property tests were performed on the obtained fluorine-containing elastomer-coated wires and cables of Examples 1 to 5 and Comparative Examples 1 to 4.

A. Tensile strength test (measurement of initial tensile strength and initial elongation) First, each of the insulated wire cores and the like were extracted from the fluorine-containing elastomer-coated wires and cables of Examples 1 to 5 and Comparative Examples 1 to 4 obtained above. The fluoroelastomer coating was removed.

Next, the collected Examples 1 to 5 and Comparative Example 1
Each of the fluoroelastomer coating layers Nos. 1 to 4
A tensile test was performed according to SK-6301, and a tensile strength (MPa) and an elongation (%) were measured.

The fluoroelastomer coating layers of the other Examples 1 to 5 and Comparative Examples 1 to 4 collected above were
Abrasion samples each having a thickness of 0.8 mm were prepared, and a tensile test was performed on each of them according to JIS-K-6301 to measure tensile strength (MPa) and elongation (%).

B. Dielectric breakdown voltage test Regarding the fluorine-containing elastomer-coated wires and cables of Examples 1 to 5 and Comparative Examples 1 to 4 obtained above, 5
A sample of 0 cm length was taken.

Next, each was immersed in water, and then an alternating voltage was applied between the conductor of the fluorine-containing elastomer-coated electric wire / cable and water at a rate of 1,000 V / min while increasing the breakdown voltage. Was measured.

C. Heat aging resistance (measurement of tensile strength and elongation after heat aging) For the fluorine-containing elastomer-coated electric wires and cables of Examples 1 to 5 and Comparative Examples 1 to 4 obtained above, 5
A sample of 0 cm length was taken.

Next, these fluorine-containing elastomer-coated electric wires and cables were heated at a temperature of 232 ° C. and an air displacement of 200 times /
The sample was placed in an Hr gear oven heat aging test tank and heat-aged for 7 days.

After completion of the heat aging, the cores of the insulated wires and the like were respectively extracted to take out the fluorine-containing elastomer coating layer.

Next, the collected Examples 1 to 5 and Comparative Example 1
Each of the fluoroelastomer coating layers Nos. 1 to 4
A tensile test was performed according to SK-6301, and a tensile strength (MPa) and an elongation (%) were measured.

D. Cut-through resistance The fluorinated elastomer-coated electric wires / cables of Examples 1 to 7 and Comparative Examples 1 to 4 obtained above are UL sub.
A cut-through resistance test was performed at 200 ° C. according to JECT 758.

[Characteristic Test Results of Fluorine-Containing Elastomer-Coated Wires and Cables] Table 2 shows the characteristic test results of the fluorinated elastomer-coated wires and cables of Examples 1 to 5 and Comparative Examples 1 to 4.

[0061]

[Table 2]

As can be seen from Table 2, the fluorine-containing elastomer-coated electric wire / cable of Comparative Example 1 had a tensile strength of 10.2.
kg and a very low dielectric breakdown voltage of 10 kv.

The fluorine-containing elastomer-coated electric wire of Comparative Example 2
The cable has a drawback that the initial elongation is as small as 140% and the elongation after heat aging is reduced to 50% of the initial value.

The fluorine-containing elastomer-coated electric wire of Comparative Example 3
The cable has the poorest cut-through resistance of 50.

The fluorine-containing elastomer-coated electric wire of Comparative Example 4
The cable has a drawback that the initial elongation is the smallest and the elongation after heat aging is reduced to 55% of the initial value.

On the other hand, the fluorine-containing elastomer-coated electric wires and cables of Examples 1 to 5 have a large initial tensile strength and elongation, a large tensile strength and elongation after thermal aging, and a large dielectric breakdown voltage. Furthermore, the cut-through resistance is excellent.

[0067]

The fluorine-containing elastomer-coated electric wire of the present invention
Cables have excellent flexibility, heat resistance, heat stability, electrical insulation, oil resistance, chemical resistance, and flame retardancy.
It has high initial tensile strength and elongation, which has been a difficult point in the past, and has high tensile strength and elongation after thermal aging. In addition, it has high dielectric breakdown voltage and excellent cut-through resistance. is there.

[Brief description of the drawings]

FIG. 1 shows a cross section of a fluorine-containing elastomer-coated electric wire / cable according to a first embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Copper stranded wire 2 Insulation layer 3 Insulated wire core 4 Inclusion layer 5 Fluorine-containing elastomer coating layer

Claims (4)

[Claims] 1. A fluorine-containing elastomer-coated electric wire or cable comprising a conductor or an outer periphery of an insulated wire core coated with a fluoropolymer composition, wherein the fluoropolymer composition has a particle diameter of 0.5 μm or less in the fluoropolymer. A fluorine-containing elastomer-coated electric wire / cable characterized by being mixed with calcium carbonate. 2. The method according to claim 1, wherein the fluoropolymer is a tetrafluoroethylene-propylene copolymer, an ethylene-tetrafluoroethylene copolymer, or a tetrafluoroethylene copolymer.
The fluoroelastomer-coated electric wire / cable according to claim 1, characterized in that it is a blended fluoropolymer of a propylene copolymer and an ethylene-tetrafluoroethylene copolymer. 3. The fluoroelastomer-coated electric wire or cable according to claim 1, wherein the calcium carbonate in the fluoropolymer composition is finely dispersed so as to have an aggregate diameter of 5 μm or less. 4. The fluoropolymer composition is a fluoropolymer 1
The fluorine-containing elastomer-coated electric wire / cable according to claim 1, wherein 20 to 100 parts by weight of calcium carbonate having a particle size of 0.5 µm or less is mixed with 00 parts by weight.