JPH09282951A - Fireproof cable - Google Patents

Abstract

(57) Abstract: [PROBLEMS] To provide a fire resistant cable capable of further reducing the manufacturing cost while maintaining the insulation characteristics and the high temperature withstand voltage characteristics that pass the fire resistance certification standard. SOLUTION: To 100 parts by weight of talc having a particle size of 5 μm or less, 1 to 9 parts by weight of silica having a particle size of 1 μm or less, 50 to 130 parts by weight of methylphenyl silicone resin, and 0.1 to 0. A liquid composition containing 4 parts by weight and 50 to 110 parts by weight of a liquid diluent is applied to a conductor to form a refractory layer, and an insulating layer made of a polyolefin resin is provided thereon and, if necessary, on the insulating layer. The sheath is provided with a sheath to obtain the fire resistant cable of the present invention.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention can withstand long-term use even when exposed to high heat or flame due to fire or the like.
The present invention relates to a fire-resistant cable having a synthetic resin insulating layer.

[0002]

2. Description of the Related Art Generally, in places where many people gather, such as theaters and department stores, when an emergency such as a fire occurs, it is necessary to safely guide people in the hall to an emergency exit. In such a case, even if the emergency exit guide light itself is not destroyed, if the power transmission cable is exposed to high heat, flame, etc., a short circuit may occur in a short time and the power transmission may stop. There is. However, since the emergency exit guide light is required to be lit for a certain period of time, the cable for supplying power to the emergency exit guide light does not break the insulation even when it is exposed to high heat, flame, etc. It is necessary to be able to supply.

[0003] Some fire-resistant cables used for such a purpose have a structure as shown in FIG. That is, the fireproof cable 1 is formed by forming the fireproof layer 3 on the outer periphery of the conductor 2, covering the outer periphery thereof with the insulating layer 4 made of polyethylene, and further covering the outer periphery thereof with the sheath 5. As shown in FIG. 2, the fire-resistant layer 3 of the fire-resistant cable 1 is formed by bonding a mica layer 32 to a base layer 31 made of an inorganic material such as a glass fiber cloth.
Glued mica sheet 33 having a thickness of about 0.01 to 0.15 mm
And the reinforcing layer 34 were bonded together to form a tape shape.

In order to satisfy the insulation characteristic and the withstand voltage characteristic at a high temperature of 840 ° C. or higher, which is the fireproof certification standard defined by the Fire Service Agency Notification No. 7, such a fireproof cable has the above-mentioned fireproof tape 2 to Since the three sheets were formed by wrapping them in a 1/2 to 1/4 stack, or by winding them vertically, the thickness of the refractory layer was 450 to 600 μm,
When the sheath is coated on the refractory layer, the cable becomes thick, which is not only inferior in flexibility but also cannot be reduced in weight, resulting in poor handling.

Therefore, in recent years, a method of forming a refractory layer of a ceramic coating on a conductor by using a dipping method in which a conductor is dipped and run in a coating solution containing ceramic particles and a silicone resin (for example, Japanese Patent Publication No. 63-3
No. 7922) has been proposed. However, in this method, general heat-resistant insulation and withstand voltage characteristics can be imparted, but the fire resistance certification standard specified by the Fire and Disaster Management Agency Notification No. 7 (insulation resistance after heating to 840 ° C is 0.4 MΩ or more) Therefore, the insulation withstand voltage of 1500 V for 1 minute could not be satisfied.

[0006] Further, as a cable that improves the surface smoothness of the fire-resistant cable obtained by the dipping method and has flexibility, and that conforms to the fire resistance certification standard of the Fire Service Agency, methylphenyl silicone resin and A conductor is dipped in a mixture of a diluent, a silane coupling agent, and talc having a particle size of 3 μm or less to form a refractory layer, and an insulator such as polyethylene is coated on the refractory layer. (Japanese Patent Laid-Open No. 7-105733) has been proposed.

[0007]

However, in such an improved fire-resistant cable, it is necessary to use finely ground talc powder having a particle size of 3 μm or less in order to meet the fire resistance certification standard. However, the use of such special materials is not economical. And in order to avoid that problem, if you use relatively inexpensive talc powder with loose pulverization, not only the smoothness of the fireproof layer is lost, but also the high temperature withstand voltage characteristics of the cable deteriorate and the fireproof certification There was a problem that the standard could not be met.

[0008] Therefore, an object of the present invention is to provide a fire resistant cable which can further reduce the manufacturing cost while maintaining the insulation characteristics and the high temperature withstand voltage characteristics that pass the fire resistance certification standard.

[0009]

A refractory cable of the present invention that can achieve the above object comprises a methylphenyl silicone resin, a silane coupling agent, talc having a particle size of 5 μm or less, and silica having a particle size of 1 μm or less. It is characterized in that a refractory layer made of the composition is provided. Further, an insulating layer made of a polyolefin resin may be provided on the fire resistant layer, and a sheath may be provided on the insulating layer if necessary.

Further, the fire resistant cable of the present invention has a particle size of 1 μm with respect to 100 parts by weight of talc having a particle size of 5 μm or less.
A liquid composition containing 1 to 9 parts by weight of the following silica, 50 to 130 parts by weight of a methylphenyl silicone resin, 0.1 to 0.4 parts by weight of a silane coupling agent, and 50 to 110 parts by weight of a liquid diluent. It can be manufactured by forming a refractory layer by applying an object to a conductor.

[0011]

DETAILED DESCRIPTION OF THE INVENTION The fire resistant cable of the present invention has essentially the same structure as a conventional fire resistant cable as shown in FIG. 1, except that its fire resistant layer 3 has a specific composition. However, it is different from the conventional fire resistant cable in that it is formed by applying the liquid composition to the surface of the conductor 2. However, the point that the insulating layer 4 is coated on the refractory layer 3 and the sheath 5 is coated on the insulating layer 4 is the same as the conventional refractory cable.

In the fireproof cable of the present invention, talc, which is a fireproofing material used for the fireproof layer, must be in the form of fine powder in terms of withstand voltage characteristics. The particle size of such talc, that is, the one having a mode value by weight of 5 μm or less can be used, and preferably the maximum particle size does not exceed 20 μm. The smaller the particle size of such talc is, the better the insulation property and withstand voltage property are, but on the other hand, there is a problem that the crushing cost is high and dust is remarkably generated to make the handling difficult. And the larger one is preferable.

Silica, which is blended with talc as a fire resistance-imparting material, also needs to be in the form of fine powder, and its particle size is 1 μm or less, particularly preferably 0.1 μm.
It is as follows. As such fine powdery silica, so-called white carbon, which is amorphous silica having a unit particle diameter of 50 nm or less, is preferably used, but either dry or wet production method may be used.

The compounding amount of such fine powdery silica is 1 to 9 parts by weight per 100 parts by weight of talc. When the content of silica is less than 1 part by weight, the withstand voltage characteristics are not improved, and when it is more than 9 parts by weight, not only the smoothness of the applied fireproof layer is impaired but also the withstand voltage characteristics are deteriorated. Not preferable.

To form the refractory layer of the refractory cable of the present invention, a methylphenyl silicone resin is used as a binder for the refractory-imparting material consisting of the talc and the fine powdery silica. Such a methylphenyl silicone resin is a material suitable for maintaining the insulation characteristics and the withstand voltage characteristics at high temperatures, and the compounding amount thereof is talc 1
It is preferably 50 to 130 parts by weight per 00 parts by weight. If the amount of the methylphenyl silicone resin blended is less than this range, the surface of the fireproof layer is rough and the flexibility is insufficient, and the withstand voltage characteristics are not improved. On the other hand, if the blending amount exceeds this range, the surface of the refractory layer becomes rough and the electrical characteristics at high temperature are impaired, which is not preferable.

Further, the silane coupling agent used together with the methylphenylsilicone-based resin effectively bonds the methylphenylsilicone-based resin and the above-mentioned fire resistance-imparting material to form a uniform and dense fireproof layer. For this purpose, γ- (2-aminoethyl) aminopropyltrimethoxysilane is particularly preferably used. The special silane coupling agent is preferably added in an amount of 0.1 to 0.4 parts by weight per 100 parts by weight of talc. When the amount of the silane coupling agent is less than this range, the withstand voltage characteristics deteriorate, and even when it exceeds this range, the withstand voltage characteristics deteriorate.

In order to form the fire resistant layer of the fire resistant cable of the present invention, the above-mentioned fire resistance-imparting material, methylphenyl silicone resin and silane coupling agent are mixed with a liquid diluent to form a liquid composition. Then, this is applied to the surface of the linear conductor and dried. The liquid diluent at this time is for obtaining a liquid composition having a viscosity suitable for forming a uniform coating layer of a predetermined thickness on the conductor, for example, an aromatic solvent such as xylene is preferable. Used. The amount of the liquid diluent blended is 50 to 11 per 100 parts by weight of talc.
The amount is preferably 0 parts by weight, and it is desirable to appropriately adjust the amount within the above range so that the liquid composition has a viscosity suitable for the operation for coating on the conductor.

An appropriate method can be adopted for applying the liquid composition as described above onto the conductor, but the dip coating method is preferable from the viewpoint of uniformity of the coating film.

The fire resistant cable of the present invention is obtained by applying the above-mentioned liquid composition for forming a fire resistant layer on a conductor composed of a single wire or a stranded wire by a dip coating method or the like, and drying it and then insulating it with a polyolefin resin or the like. It can be manufactured by coating, and if necessary, covering with a synthetic resin sheath for protection, a metal tape or the like.

[0020]

EXAMPLES Methylphenyl silicone resins (Toray Dow Corning Silicone, SH-
805) and a silane coupling agent (γ- (2-aminoethyl) aminopropyltrimethoxysilane) are mixed with a liquid diluent (xylene), finely pulverized talc is added thereto, and fine powdery silica is further added. In addition, a liquid composition was produced. The finely pulverized talc used in this case had a particle size of 2.1 μm (particle size distribution of 8 to 0.6 μm) manufactured by Fuji Talc Co., Ltd.,
The particle size is 4.5 μm (particle size distribution 10 to 0.8 μm), the particle size is 9.0 μm (particle size distribution 20 to 0.8 μm), and the fine powder silica has a unit particle size manufactured by Nippon Aerosil Co., Ltd. It was 16 nm.

[0021]

[Table 1]

Into a dip coating apparatus containing these liquid compositions, a single-wire copper conductor having a diameter of 1.6 mm was introduced, the liquid compositions were applied to the conductor surface, the solvent was removed and dried, and then at 150 ° C. for 3 minutes. By baking, a cable core having a fire-resistant layer having a thickness of 0.17 mm was obtained. Next, the fireproof cable core was coated with a polyethylene insulating coating having a thickness of 0.75 mm, and further coated with a 1.4 mm thick sheath made of polyethylene to obtain a fireproof cable having an outer diameter of 6.24 mm.

A sample of the core obtained by removing the sheath and the insulating coating from the fire-resistant cable thus obtained was subjected to an appearance inspection and a flexibility test, and a sample cut out from the fire-resistant cable was subjected to an insulation property at room temperature and a room temperature. Withstand voltage characteristics, insulation characteristics at high temperature, and withstand voltage characteristics at high temperature were tested, and the test results are summarized and shown in Table 1. The test methods and criteria for these tests are as follows.

[Appearance Inspection] The surface of the refractory layer of the wire core sample was visually inspected, and those having no unevenness and being uniform were evaluated as ◯, and those not having such unevenness were evaluated as x. [Flexibility] A wire core sample was wound around a mandrel having a diameter of 10 mm.

[Normal Temperature Insulation] Cable for Exposed Wiring Test Vertical 300 installed vertically on a truck that can move in and out of a heating furnace
mm, width 300 mm, thickness 10 mm perlite plate,
A 1.3 m long fire-resistant cable sample whose bending habit was corrected in advance using a 10 mm mandrel was placed at two positions 20 cm apart from the center of the fire resistant cable sample, each having a diameter of 1.6 mm.
It was mounted and fixed horizontally using a soft copper wire of mm. Then, at both ends of the bundle of two soft copper wires having a length of 1.6 mm and having a diameter of 40 mm, the both ends of a bundle of two soft copper wires having a diameter of 1.6 mm were wound around the center of the mounting position, and a 320 g weight (length 1 mm) was wound around the center of the soft copper wire. Load equivalent to twice the weight of a 3 m fireproof cable)
Was hung. In this state, 5 mm is placed between the core conductor and the fixed wire.
A DC voltage of 00 V was applied to measure the insulation resistance at room temperature, and those having a resistance value of 50 MΩ or more were evaluated as ○, and those not measured as ×. Cable Test for Conduit Wiring Similar to the cable test for exposed wiring, a thin-walled conduit with an outer diameter of 19.1 mm and a length of 40 cm was attached to the pearlite plate mounted on the bogie at a distance of 20 cm at the center. At the position of the place, it was horizontally attached and fixed by a double-wound annealed copper wire having a diameter of 1.6 mm. Then, a fireproof cable sample having a length of 1.3 m was passed through the above conduit, and the end of the conduit was filled with rock wool to fix the fireproof cable sample.
After that, measurement was performed under the same test conditions as the exposed wiring cable test, and those having a resistance value of 50 MΩ or more were marked with ◯, and those not having resistance were marked with x.

[Normal Temperature Withstanding Voltage] Cable Test for Exposed Wiring Following the above normal temperature insulation measurement, a commercial AC voltage of 1500 V is applied between the core conductor and the fixed wire, and dielectric breakdown occurs in one minute. Those that did not exist were evaluated as ○, and those that did not exist were evaluated as ×. Conduit wiring cable test Subsequent to the above room temperature insulation measurement, measurement is performed under the same test conditions as the above exposed wiring cable test. ○ If no dielectric breakdown occurs in 1 minute, ○, otherwise And

[High-Temperature Insulation] Cable Test for Exposed Wiring After carrying out the above-mentioned room temperature withstand voltage measurement, a truck with a sample of the fireproof cable is introduced into the heating furnace and the heating furnace is set to 3
The temperature was raised to 840 ° C. in 0 minutes. In this state, a DC voltage of 500 V was applied between the conductor and the fixed wire, and the insulation resistance was measured. Those that were not were evaluated as x. After conducting the normal temperature withstand voltage measurement for the conduit cable test , the measurement is performed under the same heating test conditions as the above exposed wiring cable test,
A sample having a resistance value of 0.4 MΩ or more was evaluated as ◯, and a sample having no resistance value was evaluated as x.

[High temperature withstand voltage] Cable test for exposed wiring Subsequent to the above high temperature insulation measurement, a commercial AC voltage of 1500 V is applied between the conductor and the fixed wire, and dielectric breakdown does not occur in 1 minute. Was marked with ○, and the other was marked with x. Conduit wiring cable test Subsequent to the above high-temperature insulation measurement, measurement is performed under the same test conditions as the above exposed wiring cable test. ○ If no dielectric breakdown occurs in 1 minute, ○, otherwise. And

Looking at the test results shown in Table 1, the particle size is 1 μm.
When the fine powdery silica of m or less is not added or the amount of addition is small, the high-temperature withstand voltage decreases when the particle size of talc exceeds 3 μm, whereas the fine powdery silica described above contains 100 wt. It can be seen that the high temperature withstand voltage is improved by adding 1 to 9 parts by weight to the parts.
It is also understood that if the particle size of talc exceeds 5 μm, the effect of adding fine powdery silica cannot be expected.

Further, the compounding amount of the methylphenyl silicone resin is in the range of 50 to 130 parts by weight with respect to 100 parts by weight of talc, and the compounding amount of the silane coupling agent is 1 part of talc.
It can be seen that good high-temperature withstand voltage can be expected in the range of 0.1 to 0.4 parts by weight with respect to 00 parts by weight.
Further, when the refractory layer is applied to the conductor, the amount of the liquid diluent compounded in the composition having the above composition is talc 100.
It can also be seen that 50 to 110 parts by weight are suitable with respect to parts by weight.

[0031]

EFFECTS OF THE INVENTION The fire resistant cable of the present invention comprises a combination of talc powder having a specific particle size and fine powder silica having a specific particle size in a specific ratio to form a fire resistant layer. It has excellent insulation properties that comply with the fire resistance certification standard and excellent high-temperature withstand voltage characteristics, and is economically effective. Further, it has the effect of suppressing dust generation and improving the environment of production equipment.

[Brief description of drawings]

FIG. 1 is a sectional view showing a structure of a fire-resistant cable according to the present invention.

FIG. 2 is a cross-sectional view showing a configuration of a fireproof layer in a conventional fireproof cable.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fireproof cable 2 Conductor 3 Fireproof layer 4 Insulation layer 5 Sheath 31 Base material layer 32 Grated mica layer 33 Grated mica sheet 34 Reinforcement layer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location H01B 3/46 H01B 3/46 D

Claims (3)

[Claims] 1. A refractory layer made of a composition containing a methylphenyl silicone resin, a silane coupling agent, talc having a particle size of 5 μm or less and silica having a particle size of 1 μm or less is provided on the surface of a linear conductor. Fireproof cable to. 2. The fire resistant cable according to claim 1, wherein an insulating layer made of a polyolefin resin is provided on the fire resistant layer. 3. A methylphenyl silicone resin 50 to
130 parts by weight, silane coupling agent 0.1-0.4
Parts by weight, 100 parts by weight of talc having a particle size of 5 μm or less, 1 to 9 parts by weight of silica having a particle size of 1 μm or less, and a liquid diluent 50.
A method for producing a refractory cable, characterized in that the refractory layer is formed by applying a liquid composition containing about 110 parts by weight to a conductor.