JPS5914843B2 - Fireproof wire with shield - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a shielded refractory electric wire, and particularly to a shielded refractory electric wire suitable for being drawn into a conduit.

Conventionally, shielded fire-resistant electric wires have been used in which a metal tape is wound over a fire-resistant insulated wire core, and a flame-retardant polyethylene sauce is applied thereon.

However, in fire-resistant wires with such a structure10, the outside of the fire-resistant insulated wire core is covered with metal tape, so in the event of a fire, the wires are steamed, and the conductive chlorine generated thereby The drawback was that gas entered the refractory layer of the refractory insulated wire core, reducing the fireproof properties. For this reason, attempts have been made to wrap the metal tape with a gap or to use a metal braid instead of the metal tape in order to prevent the conductive gas from entering the fireproof layer. However, in the former case, since the metal tape is wound with a gap, the electric resistance of the current flowing through the shielding layer becomes large and the shielding effect is reduced accordingly. Also,
For example, when extending the above-mentioned electric wire along a laying route of about 1000 m that has several bends, the metal tape of the above-mentioned electric wire may be bent frequently during the wiring, and the metal tape may break off. 5. Otherwise, the connection portion of the metal tape connected during manufacturing may come off, resulting in a disadvantage that the shielding effect of the shielded fireproof electric wire is significantly reduced. In the latter method, compared to the former method of manufacturing wires with metal tape shielding,
This has the disadvantage that the number of work steps increases by one step, and the work speed is also 10 times slower and the cost is higher. On the other hand, polyolefin compositions are used as sheath materials for fireproof wires, but these compositions are flammable as they are, so
It was unsuitable as a sheath material for fireproof electric wires. For this reason, in order to impart flame retardancy to poly-15 olefin compositions, attempts have been made to add halogen-based flame retardants, but in this case, the same disadvantages as mentioned above occur, so it is not preferable. Ta. Furthermore, attempts have been made to obtain the desired flame retardant effect by adding only inorganic flame retardants such as aluminum hydroxide to polyolefin compositions; It is necessary to incorporate a fairly large amount of flame retardant, which has the disadvantage that the mechanical properties, electrical properties, processability, etc. of the polyolefin are significantly reduced.

The present invention has been made to eliminate these drawbacks, and by vertically attaching copper wire directly below or directly above the copper tape gap winding layer and using a non-halogen flame retardant as the sheath material of the fireproof wire, it is possible to of? The object of the present invention is to provide a shielded fire-resistant electric wire that satisfies the shielding characteristics and fire-resistance characteristics.

The present invention will be explained below based on the drawings of one embodiment.

In FIG. 1, the shielded refractory electric wire according to the present invention includes a refractory insulated wire core 1, a copper tape 2 gap-wound around the outer circumference of the refractory insulated wire core 1, or a circumference of the outer circumference of the wire cores, and a gap-wound layer of the copper tape gap-wound layer. It mainly consists of a flame-retardant sheath 3 provided on the copper tape, and a copper wire 4 longitudinally attached directly below or directly above the copper tape.

The fireproof insulated wire core 1 includes a conductor 5, a fireproof layer 6 made of mica glass tape or the like attached vertically to the outside of the conductor 5 so that the mica side faces the conductor 5, and an insulator 7 made of polyethylene or the like provided outside the fireproof layer. It is made up of.

The copper tape 2 is wound horizontally with gears of, for example, about three threads.

The purpose of providing a gap is to prevent conductive gas from being hidden behind the fireproof layer during combustion. The copper wire 4 is made of a stranded copper wire or the like, and at least one wire is attached vertically so as to be electrically connected to the copper tape 2.

Here, the reason for using copper tape as the shielding layer will be described.

Typically, the shielding layer is formed by a wrap of copper or aluminum tape. However, when the shielding layer of a fireproof electric wire is formed of aluminum tape, the melting point of the aluminum tape is low, so there is a drawback that it cannot pass a combustion test at 840° C. for 30 minutes. That is, since the melting point of aluminum is about 650° C., the aluminum shielding layer melts at an early stage in the event of a fire, making it difficult to achieve the desired shielding effect. Therefore, copper tape with a high melting point (approximately 10
83°C) was used.

The flame retardant sheath 3 is made of a non-halogen flame retardant material containing (a) 100 parts by weight of polyolefin, (b) 1 to 10 parts by weight of organopolysiloxane, and (c) 1 to 30 parts by weight of organic barium salt and/or red phosphorus. It is formed from a polyolefin composition. Examples of the polyolefin include polyethylene, ethylene-propylene copolymer, polybutadiene, ethylene monovinyl acetate copolymer, ethylene-ethyl acrylate copolymer, and the like.

These may be used alone or in combination. However, in this case, if a large amount of acid-containing polymer such as ethylene monovinyl acetate copolymer is used, the inside of the conduit tends to be affected by the weakly conductive gas and the insulation resistance tends to decrease somewhat. -Propylene copolymers are preferred. For organopolysiloxane, 25℃
Dimethylpolysiloxane, methylphenylpolysiloxane, etc. having a melt viscosity of 10,000 centipoise or more are suitable. These amounts are 1 to 1 per 100 parts by weight of the base polymer.
It is preferably 0 parts by weight; if it is less than this, there is no flame retardant effect, and if it is more than this, it becomes difficult to process. Examples of organic barium salts include barium stearate and barium laurate. The red phosphorus may be one containing red phosphorus, such as red phosphorus alone or a blend of red phosphorus and titanium oxide. In the present invention, the organic barium salt and red phosphorus may be used alone, or in order to achieve even greater effects, both may be used in combination.

When used alone, it is appropriate to use 1 to 30 parts by weight per 100 parts by weight of the base polymer, and when used in combination, it is appropriate to use 1 to 20 parts by weight each within a total of 30 parts by weight. If it is less than this, there will be no flame retardant effect, and if it is more than this, mechanical properties and processability will deteriorate. In the flame-retardant sheath, in addition to the above compounding agents, inorganic fillers such as talc, clay, aluminum hydroxide, and magnesium carbonate may be added to the extent that mechanical properties are not impaired, and anti-aging agents and lubricants may be added. , a softener, etc. may be added as appropriate. In the figure, 8 indicates an inclusion, and 9 indicates a restraining tape.

Next, a fire resistance test was conducted on the shielded refractory electric wire obtained by the present invention (hereinafter referred to as A) and the conventional shielded refractory electric wire (hereinafter referred to as B and C), and the results are shown in FIGS. 2 and 3.
It was as shown in the figure.

Note that the above A is a shielding layer in which an annealed copper wire is vertically attached directly under the copper tape gap winding layer as a shielding layer, and a so-called non-halogen flame-retardant polyethylene sheath made of the components listed in Table 1 is extruded and coated to the required thickness as a sheath. A fire-resistant electric wire, B is a shielded fire-resistant electric wire in which a vinyl sheath is used in place of the non-halogen flame-retardant polyethylene sheath of A, and a shielding tape is wrapped around the shielding tape. Figure 2 shows the so-called unshielded ordinary fireproof electric wires that have been removed, with the wires AB and C exposed, and Figure 3 shows the wires A and C inside the conduit tube. The fire resistance test characteristics are shown when a fire resistance test is conducted with B and C inserted respectively.

In addition, the fire resistance test was conducted with J
It is heated according to the fire temperature curve of ISAl3O4 for 30 minutes, withstood, and then subjected to an insulation resistance of 0.4 MΩ or more and a withstand voltage test of ACl5OOVl.

From Figures 2 and 3, the insulation resistance of wire C was good in the exposure test, but poor in the in-tube test, about 2
Dielectric breakdown occurred in 0 minutes.

B has slightly better characteristics than C in the in-tube test, but it breaks down in about 22 minutes, and in the exposed wire test, it has better characteristics than C.
It was worse than that, and dielectric breakdown occurred in about 20 minutes. C has the required voltage resistance characteristics for both exposure and in-conduit tests,
It can be seen that the insulation resistance is 0.4 MΩ/1.3 m, which sufficiently satisfies the standard value. In the above-mentioned shielded fireproof electric wire of the present invention, a copper wire is longitudinally attached to the inside or outside of a gap-wound copper tape, and a halogen-free flame-retardant polyolefin material is used as a sheath, so it is more durable than conventional wires. It has a good shielding effect, and even if the copper tape is cut during wire installation, the copper wire can provide continuity. Furthermore, since the copper wire can be used as a grounding wire during grounding work, the grounding work can be easily performed. Furthermore, in the present invention, since copper wires made of the same material as the copper tape are longitudinally attached to the copper tape, there is no need to worry about metal corrosion between the copper tape and the longitudinally attached wires. When vertically attaching a wire of a different type to this tape, it is necessary to apply solder plating to the wire itself, but in the present invention, there is no need to form such a solder plating layer, so the conventional method of vertically attaching Compared to wires, it is easier to manufacture vertical affixed wires because there is no plating layer, and if there is a plating layer, the apparent cross-sectional area increases due to the plating layer, so the electrical resistance increases accordingly. However, in the present invention, since there is no plating layer, there is an advantage that the thickness of the vertical auxiliary lines can be made thinner. Also,
The shielded fireproof electric wire of the present invention has sufficient fireproof performance even when burned under closed conditions such as inside a conduit, and there is no deterioration in processability of the sheath material or mechanical properties as a general-purpose electric wire. , is extremely useful.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing one embodiment of the shielded refractory electric wire according to the present invention, Fig. 2 is a graph showing the fire resistance performance of various refractory electric wires in an exposed state, and Fig. 3 is a graph showing the fire resistance performance of various refractory electric wires in the conduit tube. It is a graph showing the fire resistance performance of. 1...Fireproof insulated wire core, 2...Copper tape gap, winding layer, 3...Refractory sheath, 4...
····Copper wire.

Claims (1)

[Scope of Claims] 1 A copper tape is gap-wound on the outside of an insulated wire core having a fireproof layer between a conductor and an insulator, and a refractory sheath is provided on the outside, wherein the copper tape gap is A copper wire is longitudinally attached directly below or above the winding layer, and the sheath is made of (a) 100 parts by weight of polyolefin;
(b) 1 to 10 parts by weight of organopolysiloxane, (c)
A shielded fireproof electric wire characterized in that it is formed from a non-halogenated flame-retardant polyolefin composition containing 1 to 30 parts by weight of an organic barium salt and/or red phosphorus. 2. The shielded fireproof electric wire according to claim 1, wherein the polyolefin is polyethylene and/or an ethylene-propylene copolymer.