JPH10302552A - Fire resistant electric wire-cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance fire resistance and prevent drop in insulation even if being heated for long hours by forming fire resistant layers in such specified three layer structure that a layer coming in contact with a conductor is made of a fire resistant tape, its outside layer is made of a silicone resin base material, and its outside layer is made of a fire resistant layer. SOLUTION: A fire resistant layer 2 made of a first fire resistant tape, a fire resistant layer 3 using silicone resin as a base material, and a fire resistant layer 4 made of a second fire resistant layer are arranged. As the fire resistant tape used in forming the fire resistant layers 2, 4 made of the first and second fire resistant tapes, for example, a double film mica tape, a single film mica tape, or the like is used, the fire resistant layer 2 is covered on a conductor 1, and the fire resistant layer 4 is covered on the fire resistant layer 3. As the silicone resin used for forming the fire resistant layer 3, for example, dimethyl family silicone resin, methyl vinyl family silicone resin, or the like is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to fire-resistant electric wires and cables, and more particularly to an improvement in fire resistance.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 1, a conductor is covered with a fire-resistant layer made of a silicone resin as a base material, and the outside thereof is covered with an insulator or sheath. As described above, there are known fire-resistant electric wires and cables in which a conductor is covered with a fire-resistant layer composed of two layers of fire-resistant tape, the outside is covered with an insulator, and the outside is covered with a sheath. In FIG. 1, 1 is a conductor, 2 is a refractory layer made of a silicone resin as a base material, 3 is an insulator, and 4 is a sheath. In FIG. 2, 1 is a conductor, 2 is a refractory layer made of a first refractory tape, 3 is a refractory layer made of a second refractory tape, 4 is an insulator, and 5 is a sheath.

[0003]

However, the known fire-resistant electric wires and cables are not yet sufficiently fire-resistant, and when heated for a long time, cracks and the like occur in the fire-resistant layer, resulting in a decrease in insulation. There is a problem of causing a short circuit.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of conventional fire-resistant electric wires and cables and to provide excellent fire resistance.
An object of the present invention is to provide a fire-resistant wire or cable whose insulation does not decrease even when heated for a long time. The present inventor has conducted intensive studies to achieve the above object, and as a result, the fire-resistant layer, the layer in contact with the conductor is a layer made of fire-resistant tape, the outside is a layer made of a silicone resin as a base material, and the outside is further Completed the present invention by finding that it is possible to provide a fire-resistant wire / cable that has excellent fire resistance and does not decrease in insulation even if it is heated for a long time if it has a three-layer structure with a specific arrangement of layers made of fire-resistant tape. did. Accordingly, the present invention provides a fire-resistant wire or cable in which a conductor is covered with a fire-resistant layer, and the outside of the fire-resistant layer is further covered with an insulator and a sheath. The present invention relates to a fire-resistant wire / cable characterized in that the outside has a three-layer structure including a layer made of a silicone resin as a base material and a layer made of a fire-resistant tape outside. The specific arrangement of the refractory layer is an important factor in achieving the object of the present invention, and deviates from the provisions of the present invention, for example, a layer in contact with a conductor is a layer made of a silicone resin as a base material. The object of the present invention cannot be attained by an arrangement of a fire-resistant layer in which the outside is a layer made of a fire-resistant tape and the outside is a layer made of a silicone resin as a base material.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below. FIG. 3 is a conceptual diagram of a cross section of a fire-resistant wire / cable according to the present invention. In FIG. 3, 1 is a conductor, 2 is a fire-resistant layer made of a first fire-resistant tape, 3 is a fire-resistant layer made of a silicone-based resin, 4 is a fire-resistant layer made of a second fire-resistant tape, 5 is an insulator, 6 is a sheath.

In the practice of the present invention, various known fire-resistant tapes can be used as the fire-resistant tape used to form the fire-resistant layer comprising the first and second fire-resistant tapes. For example, a double-sided film mica tape, a single-sided film mica tape, a mica glass tape, a silicone rubberized glass tape, or the like can be used. The formation of these refractory layers may be performed by a known method such as winding a refractory tape to be used around the outer periphery of the object to be coated. The object to be covered with the fire-resistant layer made of the first fire-resistant tape is a conductor, and the object to be covered with the fire-resistant layer made of the second fire-resistant tape is one coated with a fire-resistant layer made of a silicone resin.

[0007] As the silicone resin used for forming the refractory layer having the silicone resin as a base material, various known silicone resins can be used. For example, a dimethyl-based silicone resin, a methylvinyl-based silicone resin, a methylphenylvinyl-based silicone resin, or the like can be used. In addition, various known additives such as fillers and crosslinking agents can be added to the silicone-based resin, if necessary. The mixing ratio of the filler is suitably from 0 to 200 parts by weight per 100 parts by weight of the resin, and the mixing ratio of the crosslinking agent is 0.1 to 100 parts by weight of the resin.
10 to 10 parts by weight is suitable. As a filler, mica powder is used. The filler has an average particle diameter of 1 to 20.
00 μm is preferably used. As the crosslinking agent, a peroxide-based or platinum-based crosslinking agent is preferably used. The formation of the fire-resistant layer comprising the silicone-based resin as a base material may also be carried out by a known method such as an extrusion coating method. It is formed so as to cover the outside.

In the fire-resistant electric wire / cable according to the present invention, various insulators (for example, polyethylene, cross-linked polyethylene, etc.) known in the art can be used as the outermost insulator. Further, as the sheath, various kinds of conventionally known ones (for example, polyethylene and the like) can be used.

Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples. (Example 1) On a conductor having a diameter of 2 mm, a thickness of 0.225 m
m of the first fire-resistant tape layer (tape used: mica glass tape, winding method: vertical wrapping (1/2 wrap)), and a 0.45 mm thick silicone resin is used as a base material thereon. Fireproof layer (Methyl vinyl silicone resin 1
00 parts by weight, mica powder 100 having an average particle diameter of 450 μm
Parts by weight, extrusion coating of a blend of 1 part by weight of a peroxide-based crosslinking agent), and 0.225 m thick thereon.
m, a wire covered with a second fire-resistant tape layer (used tape: same as the first layer, winding method: same as the first layer) was prepared, and the heating temperature specified in JIS A 1304 for the wire was prepared. A fire resistance test was performed according to a standard curve. Table 1 shows the results.

(Comparative Example 1) Three layers of a fire-resistant tape layer (tape used: three layers in the same type as in Example 1,
Winding method: An electric wire covered by wrap winding (1/2 wrap) was prepared, and the same fire resistance test as in Example 1 was performed on this electric wire. Table 1 shows the results. (Comparative Example 2) An electric wire was prepared by coating a conductor having a diameter of 2 mm with four layers of fire-resistant tape layers (the used tape: the same type as in Example 1 and the winding method: the same as in Example 1). Was subjected to the same fire resistance test as in Example 1. Table 1 shows the results.
Shown in

(Comparative Example 3) A fireproof layer (silicone-based resin, compound, and compounding ratio) formed on a conductor having a diameter of 2 mm and having a first silicone-based resin having a thickness of 0.3 mm as a base material was used. And a 0.225 mm thick fire-resistant tape layer thereon (tape used: Example 1).
And a refractory layer (silicone-based resin, compound, compounding ratio of 0.375 mm) having a thickness of 0.375 mm as a base material. In each case, an electric wire coated with the same extrusion coating as in Example 1 was prepared, and the same fire resistance test as in Example 1 was performed on this electric wire. Table 1 shows the results. (Comparative Example 4) A thickness of 0.675 m on a conductor having a diameter of 2 mm
m with a refractory layer (extruded coating similar to that of Example 1 for all of the silicone resin, the compound, and the compounding ratio) as a base material, and a thickness of 0.225 mm on it.
(Electric tape: the same type as in Example 1, winding method: the same as in Example 1) was prepared, and the same fire resistance test as in Example 1 was performed on this electric wire. Table 1 shows the results.

Comparative Example 5 A 0.225 mm thick fire-resistant tape layer (tape used: Example 1) was placed on a conductor having a diameter of 2 mm.
And a refractory layer having a thickness of 0.675 mm as a base material (a silicone resin, a compound, and a compounding ratio). An electric wire covered with the same extrusion coating as in Example 1 was prepared, and the electric wire was subjected to the same fire resistance test as in Example 1. Table 1 shows the results. (Comparative Example 6) A fire-resistant layer comprising a 0.9 mm thick silicone-based resin as a base material on a conductor having a diameter of 2 mm (the same extrusion coating as in Example 1 for all silicone-based resins, compounds, and compounding ratios) , And the same fire resistance test as in Example 1 was performed on the electric wire. Table 1 shows the results.

[0013]

[Table 1]

As is clear from the results of the above Examples and Comparative Examples, the specific arrangement of the refractory layer specified in the present invention exhibits a unique effect in improving the fire resistance of refractory wires and cables.

[0015]

According to the present invention, there is provided a fire-resistant wire / cable which has excellent fire resistance and does not lose its insulation even after being heated for a long time.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of one conventional fire-resistant wire / cable, wherein 1 is a conductor, 2 is a fire-resistant layer made of a silicone resin as a base material, 3 is an insulator, and 4 is a sheath.

FIG. 2 is a cross-sectional view of another conventional fire-resistant wire / cable, wherein 1 is a conductor, 2 is a fire-resistant layer made of a first fire-resistant tape, 3 is a fire-resistant layer made of a second fire-resistant tape, and 4 is The insulator 5 is a sheath.

FIG. 3 is a conceptual diagram of a cross section of a fire-resistant wire / cable according to the present invention, wherein 1 is a conductor, 2 is a fire-resistant layer made of a first fire-resistant tape, 3 is a fire-resistant layer made of a silicone resin as a base material,
4 is a refractory layer made of a second refractory tape, 5 is an insulator, 6
Is a sheath.

Claims (1)

[Claims] 1. A fire-resistant wire or cable in which a conductor is covered with a fire-resistant layer, and the outside of the fire-resistant layer is covered with an insulator and a sheath. A layer comprising a silicone resin as a base material and a layer comprising a fire-resistant tape on the outside of the layer.