JPH09270208A - Fireproof electric wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fireproof electric wire having necessary flexibility as an electric wire at normal temperature and also sufficiently high fireproof property and at the same time having a fireproof layer which is not cracked or separated even heated at a relatively low temperature of 400-500 deg.C. SOLUTION: This fireproof electric wire 7 is produced by forming a sheath 4 on an insulated core wire 6 or a plurality of twisted insulated core wires 6; and the insulated core wires 6 are produced by forming a 0.2-2mm thick fireproof layer 2 directly or through another layer on the outer circumferences of conductors 1 by extrusion coating with a kneaded mixture containing 100 pts.wt of silicone polymer which practically provides flexibility, 0.5-60 pts.wt. of glass fibers having average fiber length 0.3-30mm, fiber diameter 0.1-50μm, less than 0.5wt.% of alkali metal contents (calculated as oxides), and softening temperature 900-1100 deg.C, 5-150 pts.wt. of silica powder, and a platinum compound or platinum in a proper amount to give 0.1-100ppm of the platinum content to the silicone polymer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fireproof electric wire used for an emergency power supply path or the like.

[0002]

2. Description of the Related Art Conventionally, as a fireproof electric wire, a mica tape such as a glass mica tape or a plastic mica tape is wound around a conductor to provide a fireproof layer, and a polyethylene resin or the like is extrusion-coated on this to form an insulating layer. It is known that an external protective layer is provided by further providing it with polyvinyl chloride or the like by extrusion coating.

However, in the case of a fireproof electric wire having a fireproof layer formed by winding a mica tape in this manner, the winding process of the mica tape takes time, resulting in poor productivity, and the mica used in the mica tape is easily broken and easily peeled off. Therefore, there are problems such as poor work environment for workers and lack of quality stability. Moreover, the fireproof electric wire using the mica tape has a problem that it is hard and has poor workability because sufficient fire resistance cannot be obtained unless the mica tape is wound several times. Furthermore, since mica tape is relatively expensive, the price of fireproof wires is high. In order to solve the problems of productivity, workability, processability, and price of a fireproof electric wire using such a mica tape, a fireproof electric wire using a mixture of olefin resin and hollow glass beads as a fireproof layer is disclosed in JP-A-6- 52
Proposed in No. 727.

However, in the case where a mixture of glass powder such as glass beads and an olefin resin as shown in JP-A-6-52727 is used as the refractory layer and the combustion is intense, the olefin group of the refractory layer is used. The resin softens and flows down, and at the same time, the glass powder also drops off from the conductor, or the olefin resin in the refractory layer burns and the glass powder loses the olefin resin as the adhesion medium. Insulation characteristics may not be maintained during and after combustion due to detachment from above,
Insufficient fire resistance.

A refractory wire having a refractory layer made of a mixture of silicone and inorganic powder is disclosed in Japanese Patent Laid-Open No. 49-417.
5, JP-B-57-25930, JP-A-51-149
No. 578 and Japanese Patent Laid-Open No. 5-254912. Even if silicone is burned, unlike other organic polymers, since it becomes silica after burning and some ash residue remains, this may be used as an insulator during and after burning. Then, by mixing the inorganic powder, which remains reliably after combustion, with silicone, there is a possibility that the insulation residue after combustion is further increased and the fire resistance can be obtained.

[0006]

However, in the case where silicone having flexibility, represented by silicone rubber, is merely mixed with a powdered inorganic material, a large amount of insulation residue remains when burned, but the remaining insulation remains. The residue is extremely fragile and may fall off even if a little load is applied, or it may fall off spontaneously, which is extremely insufficient as a fireproof layer for a fireproof electric wire. Thus, in the electric wire with a refractory layer made by simply mixing inorganic powder into the conventionally proposed silicone rubber, the problem of falling off when the refractory layer burns,
There was a problem of cracking, which was a serious problem for practical use as a fireproof electric wire.

[0007] Further, the line proposed as a refractory layer made of a mixture of the above silicone rubber and inorganic powder has a relatively rapid temperature change of 840 as shown in the heating temperature curve in the fire resistance test announced by the Fire Department. When the temperature is raised to ℃, the refractory layer is brittle, but some of it remains mineralized and hardens, but when it is kept at a temperature not too high, for example, 400 ℃ ~ 500 ℃, only the organic component of silicone is desorbed. Progresses, for example, because the binder effect of the inorganic powder due to the softening of the glass powder is not sufficiently exerted,
It has been newly found that this type of refractory layer has a problem that it becomes extremely brittle and easily falls off. The object of the present invention is to solve the above-mentioned problems, to have the flexibility required as an electric wire at room temperature and to have a sufficient fire resistance, and 400 to 500 ° C.
Another object of the present invention is to provide a refractory electric wire having a refractory layer that does not crack or drop even when heated at a relatively low temperature.

[0008]

In order to achieve the above object, in the present invention, 100% by weight of a silicone polymer exhibiting substantially flexibility a) directly on the outer circumference of a conductor or through another layer. B) Average fiber length 0.3 to 3
0 mm, fiber diameter 0.1 to 50 μm, alkali metal content less than 0.5 wt% in terms of oxide, softening temperature 900 ° C.
0.5 to 60 parts by weight of glass fiber at 1100 ° C.,
(C) 5 to 150 parts by weight of silica powder, d) 0.2 to 2 mm thick mixture obtained by kneading platinum compound or platinum in an amount such that the platinum content of the silicone polymer is 0.1 to 100 ppm. There is provided a fire resistant electric wire characterized in that a sheath is provided on an insulated wire core having a fire resistant layer extruded and coated, or on a plurality of the insulated wire cores combined together. Further, in the present invention, (b) an average fiber length of 0.3 to 30 mm with respect to 100 parts by weight of a silicone polymer that exhibits substantial flexibility, directly on the outer circumference of the conductor or through another layer. A glass fiber having a fiber diameter of 0.1 to 50 μm, an alkali metal content of less than 0.5% by weight in terms of oxide, and a softening temperature of 900 ° C. to 1100 ° C. is 0.5 to 60.
Parts by weight, c) 5-150 parts by weight of silica powder, and d) platinum content of 0.1-100 with respect to the silicone polymer.
a refractory layer obtained by extrusion-coating a platinum compound or a mixture obtained by kneading with platinum in an amount of ppm to a thickness of 0.2 to 2 mm;
Further, there is provided a fire resistant electric wire characterized in that a sheath is provided on an insulating wire core having an insulating layer provided on the outside of the fire resistant layer, or on a plurality of the insulating wire cores combined with each other. . Further, in the present invention, there is provided a fire resistant electric wire characterized in that a coating layer of glass mica tape or plastic mica tape is provided between the conductor and the fire resistant layer in the fire resistant electric wire.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
FIG. 2 shows a cross-sectional view of one embodiment of the fireproof electric wire of the present invention. In the figure, 1 is a conductor, 2 is 100 parts by weight of silicone polymer, average fiber length is 0.3 to 30 mm, fiber diameter is 0.1 to 50 μm,
Alkali metal content is less than 0.5% by weight in terms of oxide,
Glass fiber 0.5 having a softening temperature of 900 ° C to 1100 ° C
˜60 parts by weight, silica powder 5 to 150 parts by weight, a platinum compound of 0.1 to 100 ppm as platinum, or a refractory layer provided by extrusion-coating a mixture obtained by kneading platinum to a thickness of 0.2 to 2 mm, 6 Is an insulated wire core consisting of the conductor 1 and the refractory layer 2,
Reference numeral 4 denotes a sheath made of polyvinyl chloride, flame-retardant polyolefin or the like. In this embodiment, the refractory layer also serves as an insulating layer which has been conventionally provided on the refractory layer.

FIG. 1 shows a sectional view of another embodiment of the fireproof electric wire of the present invention. In the figure, 1 is a conductor, 2 is a silicone polymer 100 parts by weight, average fiber length is 0.3 to 30 mm, fiber diameter is 0.1 to 50 μm, alkali metal content is less than 0.5% by weight in terms of oxide, and softened. 0.5 to 60 parts by weight of glass fiber having a temperature of 900 ° C to 1100 ° C, silica powder of 5 to 15
0 parts by weight, a platinum compound of 0.1 to 100 ppm as platinum, or a refractory layer provided by extrusion-coating a mixture obtained by kneading platinum to a thickness of 0.2 to 2 mm, 3 has an olefin resin as a main component Insulating layers and 4 are sheaths made of polyvinyl chloride, flame-retardant polyolefin or the like.

FIG. 4 shows a sectional view of another embodiment of the present invention. In the figure, 1 is a conductor, 5 is glass mica tape,
A coating layer formed by vertically coating a plastic mica tape or a synthetic mica tape, 2 is a silicone polymer 100
Parts by weight, average fiber length 0.3 to 30 mm, fiber diameter 0.1 to
50 μm, 0.5 to 60 parts by weight of glass fiber having an alkali metal content of less than 0.5% by weight in terms of oxide, a softening temperature of 900 ° C. to 1100 ° C., and a silica powder of 5 to 150
Parts by weight, a refractory layer formed by extrusion-coating a platinum compound of 0.1 to 100 ppm as platinum or a mixture obtained by kneading platinum to a thickness of 0.2 to 2 mm, 3 is an insulation containing an olefin resin as a main component Layers 4 indicate sheaths made of polyvinyl chloride, flame-retardant polyolefin or the like.

Examples of the silicone polymer of the fire-resistant layer in the present invention include silicone rubber and silicone resin from the morphological classification, but any silicone polymer having substantially flexibility may be used, and silicone rubber is particularly preferable. It is common. Examples of the silicone rubber include silicone polymers such as methyl silicone, methyl vinyl silicone, methyl vinyl phenyl silicone, and methyl phenyl silicone, and silicone polymers mainly having a linear molecular structure are preferable.

The silicone polymer of the present invention may or may not be crosslinked.

To perform the crosslinking treatment on the refractory layer, an organic peroxide such as 2,4-dichlorobenzoyl peroxide or a known silicone crosslinking agent such as a platinum compound is mixed as a crosslinking agent into the refractory layer, and the mixture is extruded. After coating, this may be heat-treated with a known heating means to crosslink. Further, even when these cross-linking agents and the like are added, the cross-linking treatment by heating need not be performed. Compared to the product without cross-linking agent, ash is more likely to remain than the one without cross-linking agent or the one without cross-linking agent and without heat treatment. There is also a tendency to easily occur. However, in any case, sufficient fire resistance can be obtained within the range of the present invention.

The viscosity of the silicone rubber is typically 1 to 20 million centistokes, but the viscosity is not limited to this. Alternatively, a silicone rubber having an appropriate viscosity that can be extruded from the beginning may be mixed with the above glass fibers, or a silicone obtained by addition polymerization or condensation polymerization of a low-viscosity liquid silicone. An extruded composition having appropriate flexibility may be obtained by using rubber and mixing the above glass fibers in the case of liquid silicone, and then proceeding with polymerization.

Further, in the present invention, the glass fiber mixed in the mixture for forming the refractory layer 2 has an average fiber length of 0.3 to 30 mm, a fiber diameter of 0.1 to 50 μm, and an alkali metal content of oxidized. It must be less than 0.5% by weight in terms of material and have a softening temperature in the range of 900 to 1100 ° C.

If the average fiber length of the glass fibers to be mixed is too short, the refractory layer shrinks sharply during combustion, causing large cracks in the refractory layer, and entanglement between the glass fiber conductors and entanglement between the glass fibers. Since the degree of adhesion is low, the refractory layer becomes brittle and easily falls off. For this reason, glass fibers having a length of 0.3 mm or more are required. Further, if the glass fiber to be mixed is too long, the extrudability at the time of extrusion coating the refractory layer is deteriorated, and the uniform kneading and mixing property of the extrusion mixture is also deteriorated, and as a result, a fireproof electric wire having stable characteristics can be obtained. Disappear. Therefore, the average fiber length of glass fibers is preferably 30 mm or less. The diameter of the glass fiber is 0.1 to 50 μm. If the diameter of the glass fiber is too small, the reinforcing effect of the fire resistant layer at the time of combustion due to the blending of the glass fiber cannot be sufficiently obtained. On the other hand, if the glass fiber diameter is too large, the flexibility of the glass fiber is lowered, and the reinforcing effect due to the incorporation of the glass fiber cannot be sufficiently obtained.

The alkali metal content of the glass fiber is less than 0.5% by weight in terms of oxide. If it is 0.5% by weight or more, the electrical insulation characteristics at high temperature will be greatly deteriorated.
Those containing 0.5% by weight or more have a low softening temperature and a small reinforcing effect.

The softening temperature of this glass fiber must be 900 ° C. or higher. With glass fibers having a softening temperature of less than 900 ° C., cracking of the refractory layer cannot be sufficiently suppressed during combustion. Some ceramic fibers do not soften even at 1100 ° C., but since such ceramic fibers are brittle, they have little effect of suppressing cracking of the refractory layer during combustion.

The glass fibers include, for example, borosilicate glass and high silica glass, if they are classified according to their components. As the glass fiber, one obtained by bundling a plurality of glass fibers with a resin or the like may be used, or one subjected to various surface treatments may be appropriately used.

Further, regarding the blending amount of the glass fiber of the mixture of the refractory layer in the present invention, the range of the proper blending amount varies depending on the blending amount and the kind of the glass powder and the like to be blended, but taking this into consideration. It is preferably 0.5 to 60 parts by weight with respect to 100 parts by weight of the silicone polymer. It is more preferably 1 to 30 parts by weight. The glass fiber content is 0.
If the amount is less than 5 parts by weight, the reinforcing effect by the glass fiber cannot be sufficiently obtained, large cracks are generated in the refractory layer at the time of combustion, or the refractory layer becomes brittle and easily falls off. If it exceeds 60 parts by weight, the extrudability of the mixture will be poor and the kneading property will be poor, so that a fireproof electric wire with stable quality cannot be obtained.

Further, in the present invention, a trace amount of a platinum compound or platinum is mixed in the mixture of the refractory layer. It is known per se to add a platinum compound or platinum to a silicone polymer to make it flame-retardant, but in the present invention, by using it together with a specific glass fiber, it is not flame-retardant and cracks at the time of burning. It has the function of improving the fire resistance that ash is more likely to remain. Among so-called flame retardants, only platinum compounds or platinum have the action of improving such fire resistance performance, and other flame retardants do not contribute to the improvement of fire resistance performance but rather increase the insulation resistance during high temperature heating. Lower.

The platinum compound or the amount of platinum compounded is such that the platinum content relative to the silicone polymer is 0.1 to 100 pp.
m is preferred. If it is less than 0.1 ppm, cracking may occur during combustion or the material may become brittle, failing to exhibit sufficient fire resistance. Moreover, not only does it contribute much to the improvement of fire resistance performance even if it is mixed in a large amount, but rather the cost of the electric wire increases significantly due to the use of expensive platinum.

In the present invention, a fine silica powder is mixed in the mixture of the refractory layer. It is known that a silicone polymer mixed with a minute amount of silica powder has improved mechanical properties in a rubbery state before being exposed to a high temperature, but in the present invention, a platinum compound or platinum and a specific glass fiber are used. Since they are used together, the ash can be left firmly and firmly when burning, and can be prevented from falling off from the conductor. The blending amount of silica powder is 5 to 150 parts by weight based on 100 parts by weight of the silicone polymer.
If it is less than 5 parts by weight, the refractory layer becomes brittle during combustion and may fall off from the conductor, which is not preferable. If it exceeds 150 parts by weight, the mixture for the refractory layer becomes too hard and the cohesion becomes poor, resulting in poor extrusion processability. Examples of the type of silica powder include wet silica and dry silica, depending on the powder manufacturing method.

Further, ceramic powder, glass powder, natural mica powder, synthetic fluorine mica powder and clay mineral powder may be further added to the fire resistant layer of the fire resistant electric wire of the present invention. In addition, these, ceramics powder, clay mineral powder,
If mica powder or the like is added too much, the flexibility of the mixture is lost and the extrusion processability deteriorates. Therefore, the compounding amount should be appropriately selected. The amount of these powders that can be blended is at most about 350 parts by weight with respect to 100 parts by weight of the silicone polymer. And, the amount that can be kneaded is the type of each powder,
It depends on the size and shape, and also depends on the specific softening temperature, the compounding amount and the type of glass fiber having a specific fiber length, which is essential in the present invention. As a kneading means, a known kneading means such as a Banbury mixer or a roll can be used.

The refractory layer in the present invention is formed by extrusion coating the mixture having the composition described above on the conductor so that the refractory layer has a thickness of 0.2 to 2 mm. If the thickness of the refractory layer is less than 0.2 mm, cracks are likely to occur during combustion, and the fire resistance layer is too thin, resulting in poor electrical insulation properties during combustion and insufficient fire resistance performance. If the thickness exceeds 2 mm, the outer diameter of the electric wire becomes large and the workability deteriorates. Also,
Insulation resistance at high temperature may decrease, which is not preferable.

In the fireproof electric wire of the present invention, an insulating layer may be provided on the fireproof layer having the above construction. Examples of the insulating layer include an olefin resin such as polyethylene, polypropylene, an ethylene vinyl acetate copolymer, and an ethylene ethyl acrylate copolymer, a rubber such as ethylene propylene rubber and a silicone rubber, or a material containing a cross-linked product thereof as a main component. However, as long as it has excellent electrical characteristics, it is not particularly limited.

Examples of the conductor of the fireproof electric wire of the present invention include copper, nickel, silver or nickel-plated copper, silver-plated copper, stainless steel clad copper, chrome-plated copper and nickel-clad copper, but are not particularly limited. is not.

Further, in the fire resistant electric wire of the present invention, a resin composition such as polyvinyl chloride or flame retardant polyolefin, a paper tape, a flame retardant foam tape, a glass tape or the like is provided on the fire resistant layer or the insulating layer. A tape sheath made of organic or inorganic material is provided.

In addition, a coating layer serving as a second refractory layer of mica tape such as glass mica tape or plastic mica tape may be provided between the conductor and the refractory layer provided by extrusion. By providing the second refractory layer with mica tape, the fire resistance is improved. This coating layer may be provided by wrapping mica tape with wrapping, or may be provided by vertical attachment wrapping. In the case of wrapping, like a conventional fireproof wire, it may be lapped many times, but in the fireproof wire of the present invention, a fireproof layer formed by extrusion of the mixture is provided, so that a mica tape is overlaid. Even with a small number of turns, sufficient improvement in fire resistance can be obtained.

Further, in the case of vertically encasing the mica tape, it was difficult to stack the foreskin, but in the present invention, it has sufficient fire resistance without overlapping the foreskin. Therefore, even when a second refractory layer made of mica tape is provided, the conductor is vertically attached to the conductor, and the above refractory layer containing glass fibers is extrusion-coated on the conductor to efficiently and easily perform refractory electric wire. Can be manufactured. When a sheath is provided in the fireproof electric wire of the present invention, under the sheath,
In order to impart heat insulation and flame retardancy, flame retardant paper tape,
A tape such as a flame-retardant foam tape or a glass tape may be wound.

As described in detail above, the fire resistant electric wire of the present invention has 100 parts by weight of a silicone polymer which exhibits substantial flexibility and an average fiber length of 0.3 to 30 m on the outer circumference of the conductor.
m, fiber diameter 0.1 to 50 μm, alkali metal content less than 0.5% by weight in terms of oxide, and softening temperature 900 ° C. to 11
0.5 to 60 parts by weight of glass fiber in the range of 00 ° C, 5 to 150 parts by weight of silica powder, and a platinum compound or a mixture containing 0.1 to 100 ppm of platinum are extrusion-coated to have a thickness of 0.2 to 2 mm. It has a sheath on the insulated core with a refractory layer, and is flexible and flexible at room temperature before being heated to a high temperature, but is exposed to high temperatures. When exposed to a flame or burned, the refractory layer contains a specific glass fiber and a platinum compound or platinum so that the refractory layer firmly remains on the conductor. As a result, the fire resistant electric wire of the present invention has sufficient insulation performance during and after combustion and is excellent in fire resistance.

[0033]

EXAMPLES Examples of the present invention will be shown below. (Examples 1 to 12 and Comparative Examples 1 to 14) Various compositions shown in Tables 1 and 2 were kneaded using a two-roll mill to obtain an admixture to be a refractory layer. The obtained mixture is extrusion-coated to a thickness of 0.5 mm on a copper conductor having an outer diameter of 1.4 mm to form a refractory layer, and then polyethylene is extrusion-coated to a thickness of 0.8 mm to form an insulating layer. And got the insulated core. Two insulation wire cores obtained were twisted together, and a sheath made of polyvinyl chloride was extrusion-coated on the outer circumference thereof to manufacture various fire resistant electric wires having the structure shown in FIG. (Example 13) A fire resistant electric wire having the configuration shown in Fig. 2 was manufactured by the same method as in Examples 1 to 12 and Comparative Examples 1 to 14 except that the fire resistant layer was 0.8 mm thick and no insulating layer was formed. .

With respect to Examples 1 to 13 and Comparative Examples 1 to 14, the extrudability of the fireproof layer and the fireproof performance of the obtained fireproof wire were evaluated as follows. (Extrudability) The results are shown in Tables 1 and 2 when the extrudability of the above-mentioned admixture was good and there were no problems, and when the extrudability was poor, it was x.

(Fireproof performance) The obtained fireproof wires of Examples 1 to 13 and Comparative Examples 1 to 14 were heated to 850 ° C using an electric heating furnace and then kept at 850 ° C for 30 minutes. I went. Then, the insulation resistance was measured during the heat treatment and the appearance of the refractory layer after the heat treatment was evaluated.
Resistance measurement during heat treatment is 85
Measured every 5 minutes while maintaining at 0 ° C.
Those having a resistance of 4 MΩ or less were evaluated as x, those having a resistance of 0.4 MΩ or more were evaluated as ◯, and those having a resistance of 10 MΩ or more were evaluated as ⊚. The appearance of the electric wire after the heat treatment was evaluated as × when the refractory layer fell off, when the refractory layer had a large crack, or when the refractory layer was significantly deformed and the conductor was exposed. Then, ⊚ indicates that the fireproof layer remained firmly without a large crack in the state of covering the conductor, and ∘ indicates that there was a small crack but remained in the state of covering the conductor. The results are shown in Tables 1 and 2. Further, the obtained refractory electric wire was heated to 450 ° C. and then kept at 450 ° C. for 30 minutes for heat treatment. The fire-resistant wire after this heat treatment was evaluated for appearance of the fire-resistant layer in the same manner as in the heat treatment at 850 ° C. The results are shown in Tables 1 and 2.

The materials used for various blends in the examples are shown below. Silicone rubber 1: Toshiba Silicone TSE2502
5 to 60 silica per 100 parts by weight of U silicone polymer
By weight, contains 5 to 30 ppm of platinum. Contains platinum compounds or flame retardants other than platinum. Silicone rubber 2: SE1607 manufactured by Toray Dow Corning Silicone Co. Contains 5 to 60 parts by weight of silica and 5 to 30 ppm of platinum based on 100 parts by weight of the silicone polymer. Contains platinum compounds or flame retardants other than platinum. Silicone rubber 3: Toshiba Silicone TSE2425
5 to 60 silica per 100 parts by weight of U silicone polymer
Contains parts by weight. Does not contain platinum compounds or platinum or other flame retardants. Silicone rubber 4: SH410 manufactured by Toray Dow Corning Silicone Co., Ltd. Silica and a platinum compound or platinum, and other flame retardants are not contained. Silicone rubber 5: TSE201 manufactured by Toshiba Silicone Co., Ltd. Silica and platinum compound or platinum, and other flame retardants are not contained. Glass fiber 1: CST manufactured by Nitto Boseki Co., softening temperature 975
° C, average fiber length of about 13 mm, fiber diameter of 10 µm, alkali metal content of less than 0.1% by weight in terms of oxides Glass fiber 2: CST manufactured by Nitto Boseki Co., softening temperature 975
° C, average fiber length about 6 mm, fiber diameter 10 µm, alkali metal content less than 0.1% by weight in terms of oxide glass fiber 3: Nitto Boseki CST, softening temperature 975
° C, average fiber length about 0.6 mm, fiber diameter 10 µm, alkali metal content less than 0.1% by weight in terms of oxide glass fiber 4: CST manufactured by Nitto Boseki Co., softening temperature 975
° C, average fiber length about 0.2 mm, fiber diameter 10 µm, alkali metal content is less than 0.1% by weight in terms of oxide glass fiber 5: CS manufactured by Nitto Boseki Co., softening temperature 840 ° C,
Average fiber length of about 13 mm, fiber diameter of 10 μm, alkali metal content of 0.5 to 1.0% by weight in terms of oxide Ceramics fiber 1: Mitsui Mining Material Co., Ltd. Almax, alumina fiber, heat resistant temperature 1300 ° C., average fiber Length about 13 mm, fiber diameter 10 μm Ceramics fiber 2: Mitsui Mining Materials Co., Ltd. Almax, alumina fiber, heat resistance temperature 1300 ° C., average fiber length about 0.2 mm, fiber diameter 10 μm Glass powder: Nippon Horo Glaze Co., softening temperature 575 ℃ Synthetic mica powder: MK100 made by Cope Chemical Co., Ltd. Platinum paste: TC20 made by Toshiba Silicone Co., Ltd. Zinc oxide: Flame retardant Aluminum hydroxide: Flame retardant Crosslinking agent: 2,4-dichlorobenzoyl peroxide type

[0037]

[Table 1]

[0038]

[Table 2]

The following can be seen from the results of Tables 1 and 2. From the comparison between Example 1 and Comparative Examples 2, 3, 11 to 13,
When using a glass fiber having a specific average fiber length, fiber diameter, alkali metal content, and softening temperature, silica, and a mixture containing a platinum compound or platinum, the refractory layer is removed even after heating. In addition, good electrical resistance can be maintained. On the other hand, it can be seen that even if the platinum compound or the one not containing platinum is blended with other flame retardant, the refractory layer after heating falls off. Further, from the comparison between each Example and Comparative Example 1, even when the softening temperature of the glass fiber is in the range of 900 to 1100 ° C,
It can be seen that cracks occur in the refractory layer after heating in the case of using the admixture containing only fiber lengths not more than the specified length. Further, from Comparative Examples 5 and 10, the softening temperature was 900.
It can be seen that those containing only glass fibers having a temperature of ℃ or less have cracks in the refractory layer after heating at 850 ° C. Further, as in Comparative Examples 4 and 7, those containing the ceramic fiber having a very high heat resistance temperature are fragile in the ceramic fiber, so that cracks occur in the refractory layer after heating. Further, as in Comparative Example 6, when the amount of the glass fiber is more than the specified amount, the extrudability is poor and a good coating layer cannot be formed. It can be seen that, as in Comparative Example 8, if the glass powder is not contained and only the glass powder is contained, the fire resistant layer after heating is not retained on the conductor, and the required electrical insulation cannot be maintained. In addition, comparison between Example 8 and Example 9 shows that those containing no platinum compound or flame retardant other than platinum have higher insulation resistance during heating.

[0040]

The fireproof electric wire of the present invention has a silicone polymer, an average fiber length of 0.3 to 30 mm, and a fiber diameter of 0.
1 to 50 μm, and the content of alkali metal is 0.1 in terms of oxide.
Since it has a refractory layer extrusion-coated with a mixture of glass fibers having a softening temperature of less than 5% by weight and a softening temperature of 900 ° C. to 1100 ° C., a platinum compound or platinum, and silica powder, it has flexibility and is sufficient. It has a fire resistant layer and has a fire resistant layer that does not crack or fall off even when heated to a relatively low temperature of 400 to 500 ° C.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a fireproof electric wire of the present invention.

FIG. 2 is a sectional view showing another embodiment of the fireproof electric wire of the present invention.

FIG. 3 is a sectional view showing another embodiment of the fireproof electric wire of the present invention.

FIG. 4 is a cross-sectional view showing an embodiment of the fireproof electric wire of the present invention.

[Explanation of symbols]

 1 conductor 2 fireproof layer 3 insulating layer 4 sheath 5 mica tape covering layer 6 insulated wire core 7 fireproof wire

Claims (4)

[Claims] 1. A silicone polymer 100 which exhibits a substantial flexibility on the outer circumference of a conductor either directly or through another layer.
B) Average fiber length 0.3 to 30 mm, fiber diameter 0.1 to 50 parts by weight
μm, alkali metal content is 0.5% by weight in terms of oxide
Less than 0.5 to 60 parts by weight of glass fiber having a softening temperature of 900 ° C. to 1100 ° C., c) 5 to 150 parts by weight of silica powder, and d) a platinum content of 0.1 to the silicone polymer.
On the insulation core having a refractory layer obtained by extrusion-coating a platinum compound or a mixture obtained by kneading platinum in an amount of about 100 ppm to a thickness of 0.2 to 2 mm, or a plurality of the insulation cores are combined. Fireproof electric wire characterized by having a sheath on the top. 2. A silicone polymer 100 exhibiting substantially flexibility on the outer circumference of a conductor, either directly or through another layer.
B) Average fiber length 0.3 to 30 mm, fiber diameter 0.1 to 50 parts by weight
μm, alkali metal content is 0.5% by weight in terms of oxide
Less than 0.5 to 60 parts by weight of glass fiber having a softening temperature of 900 ° C. to 1100 ° C., c) 5 to 150 parts by weight of silica powder, and d) a platinum content of 0.1 to the silicone polymer.
Insulated wire core having a refractory layer obtained by extrusion-coating a 0.2 to 2 mm thick mixture of a platinum compound or a platinum compound in an amount of 100 ppm to 100 ppm, and an insulating layer provided outside the refractory layer. A fireproof electric wire, characterized in that a sheath is provided on or above the insulated cores. 3. A mica tape coating layer is provided between the conductor and the refractory layer.
Heat resistant electric wire described in. 4. The fire resistant electric wire according to claim 3, wherein the mica tape is made of synthetic mica.