JPH10334739A - Wire/cable covered with elastomer and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wire/cable covered with fluorine-contained elastomer and a manufacturing method thereof. SOLUTION: In this wire/cable covered with fluorine contained elastomer, a conductor or periphery of an insulated wire core 3 is covered with a fluorine contained elastomer blended material composed of tetrafluorethylene-propylene copolymer and ethylene-tetrafluorethylene copolymer. In this case, the fluorine- contained elastomer blended material layer has a concentration gradient in the blend concentration of the ethylene-tetrafluoroethylene copolymer along the thickness direction of the blended material. The tetrafluoroethylene-propylene copolymer and the ethylene-tetrafluoroethylene copolymer which are put in a hopper of an extruder are dry blended and extruded onto the conductor or the periphery of the insulated wire core 3 in order to cover it.

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 and a method for producing the same.

[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, tetrafluoroethylene-propylene copolymer elastomers crosslinked by irradiation with ionizing radiation or the like are widely used as heat-resistant coating materials for electric wires and 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 or cable in which a tetrafluoroethylene-propylene copolymer is thinly coated on a conductor or on the outer periphery of an insulated electric wire core is easily softened remarkably at high temperatures because of its thin thickness.

[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 was a problem that the half-plane tensile strength and the cold resistance were 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 having excellent tensile strength and excellent cold resistance, and a method for producing the same.

[0010]

The gist of the present invention lies in the following two points.

(1) A fluorine-containing elastomer-coated wire obtained by coating a conductor or an outer periphery of an insulated wire core with a fluorine-containing elastomer blend of a tetrafluoroethylene-propylene copolymer and an ethylene-tetrafluoroethylene copolymer. In the cable, the fluorine-containing elastomer blend layer is formed by coating the ethylene-containing layer along the coating thickness direction.
A fluorine-containing elastomer-coated electric wire or cable, characterized in that the blend concentration of the tetrafluoroethylene-based copolymer has a concentration gradient.

(2) The tetrafluoroethylene-propylene copolymer and the ethylene-tetrafluoroethylene copolymer put in the hopper of the extruder are extruded and coated on the conductor or the outer periphery of the insulated wire core while dry blending. A method for producing a fluorine-containing elastomer-coated electric wire or cable, comprising:

In the present invention, the fluorine-containing elastomer blend is a fluorine-containing elastomer blend comprising a tetrafluoroethylene-propylene copolymer and an ethylene-tetrafluoroethylene copolymer in a weight ratio of 95/5 to 50/50. .

In the present invention, the fluorine-containing elastomer blend is a blend 100 comprising a tetrafluoroethylene-propylene copolymer and an ethylene-tetrafluoroethylene copolymer in a weight ratio of 95/5 to 50/50.
This is a fluorine-containing elastomer blend obtained by adding 60 to 200 parts by weight of an inorganic filler to parts by weight.

Further, in the present invention, the blend concentration of the ethylene-tetrafluoroethylene-based copolymer in the fluorine-containing elastomer blend layer is configured so as to become higher toward the outer peripheral side.

In the present invention, the blend of the ethylene-tetrafluoroethylene copolymer is dry-blended at the time of extrusion coating on electric wires and cables.

In the present invention, the inorganic filler is not particularly limited as long as it is industrially practical, but calcium carbonate and the like are particularly suitable.

According to the present invention, it is possible to obtain a fluorine-containing elastomer-coated electric wire / cable having such a constitution that the cut-through resistance is remarkably excellent and the tensile strength and the cold resistance are also excellent.

First, the cut-through resistance is remarkably improved by adding a large amount of an inorganic filler such as calcium carbonate.

Second, the tensile properties and cold resistance are improved by blending an ethylene-tetrafluoroethylene copolymer.

Third, the blending of the ethylene-tetrafluoroethylene copolymer is carried out by a dry blending method at the time of extrusion coating onto a conductor or an outer periphery of an electric wire core, whereby an ethylene-tetrafluoroethylene copolymer is obtained. The blend concentration can easily have a concentration gradient along the coating thickness direction.

That is, in the present invention, these first to third effects act synergistically to provide a fluorine-containing elastomer-coated electric wire / cable having not only excellent cut-through resistance but also excellent tensile strength and cold resistance. You can get it.

[0023]

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

In the present invention, tetrafluoroethylene
As the propylene copolymer, a copolymer composed of tetrafluoroethylene and propylene, or a copolymer of tetrafluoroethylene, propylene and another copolymerizable component can be used.

Examples of such copolymerizable components include methacrylic acid, alkyl methacrylate, vinyl fluoride, vinylidene fluoride, hexafluoropropene, chloroethyl vinyl ether, glycidyl vinyl ether,
Chlorotrifluoroethylene, perfluoroalkyl vinyl ether and the like.

Here, in the copolymer with tetrafluoroethylene, propylene and other copolymerizable components, the content of the copolymerizable component is 50 mol% or less, particularly preferably 30 mol% or less. is there.

In the present invention, the fluorine-containing elastomer blend is used for improving tensile strength, cold resistance and workability.
Weight ratio 95/5 to 50 of tetrafluoroethylene-propylene and ethylene-tetrafluoroethylene copolymer
/ 50 fluoroelastomer blend. A particularly preferred fluorine-containing elastomer blend is a fluorine-containing elastomer blend having a weight ratio of tetrafluoroethylene-propylene to ethylene-tetrafluoroethylene copolymer of 90/10 to 45/55.

In the present invention, the ethylene-tetrafluoroethylene copolymer is a copolymer of ethylene and tetrafluoroethylene or a copolymer of ethylene, tetrafluoroethylene and another copolymerizable component. Particularly, a copolymer of ethylene, tetrafluoroethylene and another copolymerizable component is preferable. Among them, preferred is a copolymer of ethylene, tetrafluoroethylene and fluoroolefin.

Here, as the fluoroolefin, chlorotrifluoroethylene, vinylidene fluoride, trifluoroethylene, 1,1-dihydroperfluoropropene-1,1,1-dihydroperfluorobutene, 1,1
1,5-trihydroperfluoropentene-1,1,1
1,7-trihydroperfluoropentene-1,1,
1,2-trihydroperfluorohexene-1,1,2
-Trihydroperfluorooctene-1, perfluoro (methyl vinyl ether), perfluoro (ethyl vinyl ether), hexafluoropropylene, perfluorobutene-1, 3.3, 3-trifluoro-2-trifluoromethylpropene-1 Etc.

The copolymer of ethylene, tetrafluoroethylene and fluoroolefin herein may have a molar ratio of ethylene / tetrafluoroethylene / fluoroolefin of 10 to 40/90 to 60 / 0.1 to 20. desirable.

In the present invention, the fluorine-containing elastomer blend comprises a weight ratio of tetrafluoroethylene-propylene to ethylene-tetrafluoroethylene copolymer of 95 /
This is a fluorine-containing elastomer blend obtained by adding 60 to 200 parts by weight of an inorganic filler to 100 parts by weight of a blend of 5 to 50/50. The reasons for these limitations are as follows. That is, when the amount of the inorganic filler is 60 parts by weight or less, the effect of improving the cut-through resistance is not seen, and when the amount is 200 parts by weight or more, the tensile strength and the cold resistance are remarkably deteriorated.

Here, the inorganic filler may be used as it is, or may be one which has been surface-treated with vinylsilane, aminosilane, fatty acid or the like.

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.

[0034]

EXAMPLES Next, examples of a fluorine-containing elastomer-coated electric wire / cable of the present invention and a method for producing the same will be described together with comparative examples.

[0035]

[Table 1]

[Preparation of Tetrafluoroethylene-Propylene Copolymer Base] First, ethylene-tetrafluoroethylene copolymers were removed from Examples 1 to 7 and Comparative Examples 1 to 5 according to the composition table in Table 1. The composition, that is, the tetrafluoroethylene-propylene copolymer base material was weighed and collected. For example, Embodiment 1 is as follows.

[0038] Tetrafluoroethylene-propylene copolymer 80 parts by weight Cross-linking aid 1 part by weight Lubricant 1 part by weight Calcium carbonate 60 parts by weight Here, the number average molecular weight of the tetrafluoroethylene-propylene copolymer is 100,000.

The crosslinking aid is triallyl isocyanurate.

Furthermore, the lubricant is barium stearate.

[Preparation of Tetrafluoroethylene-Propylene Copolymer Base Pellets] Next, each of the weighed and collected tetrafluoroethylene-propylene copolymer base materials of Examples 1 to 7 and Comparative Examples 1 to 5 was 50
The mixture was kneaded with a kneading roll heated to 加熱 60 ° C. for 15 minutes to prepare a tetrafluoroethylene-propylene copolymer base pellet.

[Preparation of fluorine-containing elastomer blend]
Next, for Examples 1 to 7 and Comparative Examples 1 to 5 in Table 1,
The corresponding ethylene-tetrafluoroethylene-based copolymers were collected, and each of them was dried onto the tetrafluoroethylene-propylene copolymer base pellets obtained above, whereby Examples 1 to 7 were obtained.
And the fluorine-containing elastomer blend of Comparative Examples 1-5 was obtained.

[Extrusion coating on electric wires and cables] The fluoroelastomer blends of Examples 1 to 7 and Comparative Examples 1 to 5 obtained above were heated at a cylinder head temperature of 250 ° C.
The temperature of the cylinder 1 was 280 ° C., the temperature of the cylinder 2 was 300 ° C., and L / D = 22. The extruder was placed in a hopper of a 40 mm extruder, and then extruded and coated while being dry-blended in the hopper.

Here, Examples 1 to 5 and Comparative Examples 1 to
In the case of the fluorine-containing elastomer-coated electric wire / cable No. 5, extrusion coating was carried out on a stranded copper wire having a conductor cross-sectional area of 75 mm ² so as to have a coating thickness of 0.4 mm.

In the case of the fluorine-containing elastomer-coated electric wires and cables of Examples 6 and 7, the coating was extruded to a coating thickness of 1.0 mm on the outer periphery of the insulated electric wire core formed by twisting two cross-linked polyethylene insulated electric wires. did.

FIG. 1 shows a cross section of the thus obtained fluorine-containing elastomer-coated electric wire and cable of Example 6.

In FIG. 1, 1 is a copper stranded wire, 2 is a cross-linked polyethylene insulating layer, 3 is a cross-linked 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, other insulating layers, for example, a fluorine-containing elastomer, a vinyl chloride resin admixture, various rubbers and the like may be used.

Further, the fluorine-containing elastomer blend placed in the hopper of the extruder is extruded and coated on a copper stranded wire. At this time, the ethylene-tetrafluoroethylene copolymer component constituting the fluorine-containing elastomer blend is used. Is a resin having good thermal fluidity, and thus flows in a large amount on the outer peripheral side of the coating thickness to be coated. In other words, the ethylene-tetrafluoroethylene-based copolymer component increases toward the outer periphery of the coating thickness.

[Preparation of Fluorine-Containing Elastomer-Coated Wires / Cables] Next, the extruded coated wires / cables of Examples 1 to 7 and Comparative Examples 1 to 5 obtained above were respectively passed through an ionizing radiation irradiation furnace. Irradiation with an electron beam of 10 Mrad was carried out to crosslink, thereby obtaining fluorine-containing elastomer-coated electric wires and cables of Examples 1 to 7 and Comparative Examples 1 to 5.

[Method of Testing Characteristics of Fluorine-Containing Elastomer-Coated Wires / Cables] Next, characteristics tests were performed on the fluorine-containing elastomer-coated wires / cables of Examples 1 to 7 and Comparative Examples 1 to 5 obtained above.

A. Tensile strength test First, copper stranded wires were extracted from each of the obtained fluorine-containing elastomer-coated electric wires and cables of Examples 1 to 7 and Comparative Examples 1 to 5, and a fluorine-containing elastomer coating layer was taken out.

Next, the collected Examples 1 to 7 and Comparative Example 1
Each of the fluoroelastomer coating layers Nos. 1 to 5
A tensile test was performed according to SK-6301.

B. Cold Resistance A sheet having a thickness of 2 mm was prepared for each of the fluorine-containing elastomer blends of Examples 1 to 7 and Comparative Examples 1 to 5, and then subjected to an embrittlement test according to JIS-K-6301.

C. Cut-through resistance The fluorinated elastomer-coated electric wires and cables of Examples 1 to 7 and Comparative Examples 1 to 5 obtained as described above were UL sub.
A cut-through resistance test was performed at 200 ° C. according to JECT 758.

[Characteristic Test Results of Fluorine-Contained Elastomer-Coated Wires and Cables] The characteristic test results of the fluorinated elastomer-coated wires and cables of Examples 1 to 7 and Comparative Examples 1 to 5 are shown in Table 1 above.

As can be seen from Table 1, the fluorine-containing elastomer-coated electric wire / cable of Comparative Example 1 does not have a dry blending property because the ethylene-tetrafluoroethylene copolymer component is not blended. The tensile strength is as low as 10.2 kg, the cold resistance is poor enough to be brittle at 0 ° C., and the cut-through resistance is also extremely poor at 250 g.

The fluorine-containing elastomer-coated electric wire of Comparative Example 2
The cable has a dry blending property because the ethylene-tetrafluoroethylene-based copolymer component is blended, but the drawback is that the elongation is extremely small.

The fluorine-containing elastomer-coated electric wire of Comparative Example 3
Although the cable is blended with an ethylene-tetrafluoroethylene copolymer component but is not intentionally dry-blended, the cut-through resistance is the worst at 150 g.

The fluorine-containing elastomer-coated electric wire of Comparative Example 4
The cable has a dry blending property because the ethylene-tetrafluoroethylene copolymer component is blended, but the tensile strength is the smallest at 5.7 kg and the cold resistance is 0 ° C.
Bad enough to embrittle.

The fluorine-containing elastomer-coated electric wire of Comparative Example 5
Although the cable is a blend of ethylene-tetrafluoroethylene copolymer components but is not intentionally dry blended, the tensile strength is 10.2 kg.
And the cold resistance is so poor that it becomes brittle at 20 ° C., and the cut-through resistance is extremely poor at 300 g.

On the other hand, the fluorine-containing elastomer-coated electric wires and cables of Examples 1 to 7 have a dry blending property because the ethylene-tetrafluoroethylene copolymer component is blended. 3kg or more, excellent in cold resistance so as not to be brittle even at 40 ℃,
Further, the cut-through resistance is excellent at 600 g or more.

[0062]

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 tensile strength and excellent cold resistance, which have conventionally been regarded as difficult points, and also has excellent cut-through resistance, which is industrially useful.

[Brief description of the drawings]

FIG. 1 shows a cross section of a fluorine-containing elastomer-coated electric wire / cable according to a sixth 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 (5)

[Claims] 1. A fluorine-containing elastomer-coated wire comprising a conductor or an outer periphery of an insulated wire core coated with a fluorine-containing elastomer blend of a tetrafluoroethylene-propylene copolymer and an ethylene-tetrafluoroethylene copolymer. In the cable, the fluorine-containing elastomer blend layer is configured so that the blend concentration of the ethylene-tetrafluoroethylene-based copolymer has a concentration gradient along the coating thickness direction. Fluoro-elastomer coated wires and cables. 2. A fluorine-containing elastomer blend comprising a tetrafluoroethylene-propylene copolymer and an ethylene-tetrafluoroethylene copolymer in a weight ratio of 95/5 to 5/5.
The fluorine-containing elastomer-coated electric wire / cable according to claim 1, which is a fluorine-containing elastomer blend comprising 0/50. 3. A fluorine-containing elastomer blend comprising a tetrafluoroethylene-propylene copolymer and an ethylene-tetrafluoroethylene copolymer in a weight ratio of 95/5 to 5/5.
2. A fluoroelastomer blend obtained by adding 60 to 200 parts by weight of an inorganic filler to 100 parts by weight of a 0/50 blend.
Fluoro-elastomer-coated wires and cables as described. 4. The method according to claim 1, wherein the blend concentration of the ethylene-tetrafluoroethylene-based copolymer in the fluorine-containing elastomer blend layer becomes higher toward the outer peripheral side. Fluorine-containing elastomer coated wires and cables. 5. Extrusion coating of a tetrafluoroethylene-propylene copolymer and an ethylene-tetrafluoroethylene-based copolymer placed in a hopper of an extruder onto a conductor or an outer periphery of an insulated wire core while dry blending. A method for producing a fluorine-containing elastomer-coated electric wire or cable, comprising: