JPH0722419U - Fireproof insulated cable - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a fire resistant insulated cable which has excellent fire resistance, is easy to manufacture and is easy to handle. [Structure] This fire-resistant insulated cable is an insulating cable in which a concavo-convex portion 3 is formed on the entire surface of a synthetic resin cable sheath 2, and a heat-foamable fire-resistant paint applied to at least the concave portion 3a of the concavo-convex portion 3. It consists of 4 and.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a fireproof insulated cable.

[0002]

[Prior art]

 As shown in FIG. 5, an insulated cable used for indoor wiring is usually an insulated wire 1 in which the outer periphery of a conductor 1a is covered with an insulating layer 1b of an electrically insulating synthetic resin such as polyvinyl chloride. (20 in the figure) are twisted together, and the whole is covered with a cable sheath 2 of synthetic resin such as polyvinyl chloride.

Generally, a cable coated with rubber or synthetic resin is known as a general-purpose coated cable, and is used as an insulated cable in various specifications. Since many of the insulation materials of these insulated cables are flammable, they spread, for example, due to external ignition, overheating when an abnormal current is applied, or sparks when a short circuit occurs. Sometimes.

Particularly, in the case of a cable connecting electrical equipment, since the fire spread of the cable may be a medium of fire spread between the equipment, measures for preventing the fire spread of the cable should be taken from the viewpoint of safety. Is strongly demanded. For this reason, like the above-mentioned insulated cable, the one using a synthetic resin such as polyvinyl chloride that generates a nonflammable gas as a covering material is widely used as a suitable cable.

However, in view of a fire situation caused by actual burning, it is often the case that the above-mentioned fire resistance measures are insufficient. Especially, when a multi-row cable is laid, The current situation is that the fire activity is so high that the effect of fire-resistant measures can hardly be expected. Therefore, as a fireproof measure for such insulated cables, an aqueous resin emulsion paint containing halogen components, in which non-combustible inorganic fibers and refractory materials such as mica powder are mixed on the surface of the cable, is used as a fire spread inhibitor. It has been proposed to apply it.

On the other hand, the essential role of the cable is to transmit energy, information, etc., and it is necessary to exert its function even in an emergency. In particular, the cable needs to maintain a certain function even in the case of a fire. However, not only ordinary cables but also flame-retardant cables that require insulation or coating to be flame-retardant will stop functioning in an extremely short time when an actual fire is encountered. Is the current situation.

For this reason, as an emergency cable, for example, a conductor in which mica tape or the like is wound directly as an insulating material on the conductor and fireproof measures are taken to ensure the insulation property in the event of a fire is known. There is. However, this fire resistant cable is expensive, and the flame retardancy of the synthetic resin that constitutes the insulating layer is limited, so it cannot be said that the function of the cable as a fire is sufficiently maintained.

As described above, usually, a procedure is adopted in which a predetermined flame retardant is mixed with the insulating layer 1b and the cable sheath 2 to impart fire resistance and flame retardancy to the cable. Further, a fire spread prevention coating such as Dunnecka (trade name, manufactured by Furukawa Electric Co., Ltd.) is applied to the surface of the cable sheath 2 to provide a fire spread prevention layer as the outermost layer. Insulated cables with different structures are also known.

However, recently, in response to the stricter indoor safety environment, there is an increasing demand for an insulated cable having not only fire spread prevention but also higher level fire resistance.

[0010]

[Problems to be solved by the device]

 The present invention was developed to meet the above-mentioned requirements, and an object of the present invention is to provide a fire-resistant insulated cable with significantly improved fire spread prevention and fire resistance without impairing the original function of the insulation cable. To do.

[0011]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, in the present invention, an insulating cable main body in which a concavo-convex portion is formed on the entire surface of a synthetic resin cable sheath, and at least a concave portion of the concavo-convex portion is coated. There is provided a fire resistant insulated cable characterized by comprising a heat-foamable fire resistant paint.

[0012]

[Action]

 The heat-foamable fire-resistant paint applied to the surface of the cable sheath of the fire-resistant insulated cable is, for example, a paint commercially available from Herberts GmbH (Germany) as "Unitherm" series. The above-mentioned paint is a viscous material whose viscosity at room temperature is about the same as a general paint. Moreover, its specific gravity is as light as 1.15 to 1.40, and it can be applied thinly to a desired thickness by a method such as spraying, roll coating, brush coating, etc., as with commonly known paints. it can.

When a flame hits the formed coating film, the heat is absorbed at the flame contact portion of the coating film, and the film expands and is converted into a carbide layer containing fine pores. And it works. At this time, the above-mentioned coating film usually expands about 20 to 40 times, although it depends on the film thickness, and the thermal conductivity of this carbide is almost the same as that of urethane foam at room temperature. Is excellent.

Therefore, in the case of the fireproof insulated cable of the present invention, even if the coating amount of the above-mentioned paint is small, when the coating film is exposed to the flame, the coating film expands greatly and the cable sheath Converts it into a heat-insulating layer that covers the entire surface and protects the cable sheath as well as the twisted insulated wire from flames. That is, the heat insulation layer formed by foaming the above paint upon receiving heat protects the cable from high heat from the outside due to flames, etc., thereby not only ensuring the insulation function of the cable but also the cable. It has great effects such as preventing smoke and toxic gas from being generated by the combustion of fire, and preventing the spread of fire.

If the outer surface of the cable sheath is provided with irregularities, the heat-foamable fire-resistant paint applied to the insulated cable impairs its fire resistance when the insulated cable of the present invention is manufactured or handled. It is possible to prevent the situation that the outer surface of the cable sheath is peeled off. In other words, since there is a convex portion on the surface of the cable sheath, even if the cable sheath comes into contact with or collides with other members during manufacture or handling of the insulated cable, the cable sheath will be affected and peeled off. Is only the paint applied to the convex portion. As a result, it is possible to prevent the paint applied to the concave portion on the surface of the cable sheath from peeling off.

Even in such a coating state, when a flame hits, a very large volume expansion of the coating material occurs at the flame contact portion in the coating film, and as a result, the coating material is exposed. The convex portion is also buried in the heat insulating layer, and the whole is covered with the heat insulating layer. The coating may be applied only to the concave portions of the concave and convex portions, and the convex portions may be exposed from the beginning in the state where the coating is not coated.

In addition, the uneven portion formed on the surface of the cable sheath increases the area of the entire surface to improve the adhesiveness with the above-mentioned paint applied to the surface, and to evenly apply the paint. And has the effect of facilitating topcoat treatment.

[0018]

【Example】

 Hereinafter, an insulated cable according to an embodiment will be described with reference to the accompanying drawings. Embodiment 1 FIG. 1 is a sectional view showing a sectional structure of an insulated cable of the present invention. In the figure, a plurality of insulated electric wires 1 composed of a conductor 1a and an insulating layer 1b are twisted together, and a cable sheath 2 made of polyvinyl chloride is formed around the twisted wires.

And, on the surface of the cable sheath 2, a concave convex portion 3 composed of a concave portion 3a and a convex portion 3b is formed. An enlarged view of the portion surrounded by II in FIG. 1 is shown in FIG. Here, the shapes of the concave portions 3a and the convex portions 3b are not particularly limited, but for example, in addition to the wavy concavo-convex shape as shown in the figure, a mesh pattern or a spiral shape extending in the longitudinal direction of the cable sheath 2 is used. The groove structure may be any of the above, and the essential point is that these uneven shapes are formed on the entire surface of the cable sheath 2 in a pattern.

The depth of the recess 3a is preferably 0.3 mm or more. If the depth of the concave portion 3a is shallower than 0.3 mm, the amount of the coating material applied on the concave portion 3a is small, and therefore the volume expansion amount when contacting with the flame is small. It is not enough to cover the entire surface. However, even if it is too deep, it is wasteful of paint and is meaningless in terms of fire resistance. Therefore, it is preferable to set the depth of the recess 3a to 0.3 to 5.0 mm. .

[0021] At least the heat-foamable fireproof coating material 4 is applied to the above-mentioned recess 3a. In this case, the coating material may be applied so that the entire concave and convex portion 3 is embedded in the coating material, but as shown in FIGS. 1 and 2, the concave portion 3a is embedded and the top portion of the convex portion 3b is exposed. It is preferable to apply such a coating. This is because even when the insulated cable comes into contact with or collides with other members, the cable sheath 2 only comes into contact with the convex portion 3b and does not come into direct contact with the applied paint 4 so that the paint 4 is not damaged. .

When applying the paint 4, as in the case of a normal paint, a primer having a good compatibility with the paint 4 is applied to the surface of the cable case 2 to apply a base treatment. May be. Furthermore, after applying the paint 4, a top coat of various colors may be applied thereon. Further, an appropriate amount of chop of refractory fiber such as glass fiber or various ceramic fibers may be blended with the coating material 4, and the blended product may be applied instead of the coating material 4. This is preferable because the fire resistance is further improved.

Furthermore, it is preferable to mix the paint 4 with a pigment of a predetermined color and apply the paint to the surface of the cable sheath because the presence or absence of the paint 4 can be visually recognized during wiring. In addition, after applying the coating material 4, a skin layer may be covered on the entire surface of the cable sheath for protection of the whole. In Fig. 1, the conductor 1a is made of a copper wire having a diameter of 2 mm, the insulating layer 1b is made of 20 mm of polyvinyl chloride, and 20 insulated wires made of polyvinyl chloride are twisted together. The height of the portion 3b) An insulated cable having a diameter of 20 mm covered with a polyvinyl chloride cable sheath 2 having an uneven portion 3 of 0.45 mm was prepared.

This cable sheath 2 was brushed with Unitherm C38104 (trade name, heat-foaming paint manufactured by Herberts (Germany)) to the recessed portion 3a to a depth of 0.3 mm, and the whole was air-dried. It was an insulated cable. A flame having a temperature of 800 ° C. was applied to the surface of this insulated cable with a propane gas burner, and the change with time of the temperature at the boundary between the cable sheath 2 and the insulated wire 1 was examined.

For comparison, the same test was performed on an insulated cable to which no paint was applied, and the temperature change at the boundary portion was examined. The above results are shown in Table 1.

[0026]

[Table 1] Example 2 An insulated cable was manufactured in the same manner as in Example 1 except that the surface of the insulated cable of Example 1 was brushed with Uniterm C38104 to the recess 3a to a depth of 0.4 mm.

A flame test was performed on this insulated cable in the same manner as in Example 1. The temperature inside the cable sheath 95 seconds after the initiation of flame contact was 55 ° C., and the temperature after 115 seconds was 68 ° C. . Embodiment 3 FIGS. 3 and 4 show another embodiment of the present invention.

In the case of this fireproof insulated cable, the skin layer 5 is formed by covering the entire outside of the cable of the first embodiment. The skin layer 5 is formed by extrusion coating polyvinyl chloride, for example, and has a thickness of 0.5 mm. In the case of this cable, not only the heat-foamable fire-resistant paint 4 is protected from external damage by the skin layer 5, but also when the cable is laid outdoors, for example, the skin-layer 5 causes the heat-foamable fire-resistant paint 4 to be exposed to ultraviolet rays. It is prevented from being deteriorated by rainwater and the like, so that the performance of the heat-foamable fire-resistant paint 4 is reliably maintained for a long time.

[0029]

[Effect of device]

 As is clear from the above explanation, in the fireproof insulated cable of the present invention, the heat-foaming fireproof paint used has a low specific gravity, has a large volume expansion when it comes into contact with a flame, and its foam layer has excellent heat insulating properties. There is. Therefore, in the insulated cable of the present invention, the function of the foam layer protects the cable sheath itself or the insulated wire inside the cable from flame for a relatively long time.

In addition, since the insulated cable of the present invention is provided with the uneven portion on the surface thereof, it is possible to prevent the insulated cable from contacting or colliding with other members at the time of manufacturing or handling the insulated cable. However, only the paint applied to the convex part is affected. As a result, peeling of the paint applied to the concave portion of the cable sheath is prevented. That is, the insulated cable of the present invention is easy to manufacture and handle without being impaired in fire resistance even if it is handled such as moving, stacking, and winding before the paint is sufficiently dried. .

Further, since the fire resistance of the cable can be enhanced even if the coating amount of the paint is small, the flexibility of the insulated cable is not hindered.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of a sectional structure of an insulated cable of the present invention.

FIG. 2 is an enlarged view showing a portion II of FIG.

FIG. 3 is a sectional view showing an example of a sectional structure of another insulated cable of the present invention.

FIG. 4 is an enlarged view showing a part IV in FIG.

FIG. 5 is a sectional view showing a sectional structure of a conventional insulated cable.

[Explanation of symbols]

 1 Insulated Wire 1a Conductor 1b Insulating Layer 2 Cable Sheath 3 Uneven Part 3a Recessed Part 3b Convex Part 4 Thermal Foaming Fireproof Paint 5 Skin Layer

Claims (4)

[Scope of utility model registration request] 1. An insulating cable body having a concavo-convex portion (3) formed on the entire surface of a synthetic resin cable sheath (2) and at least a concave portion (3a) of the concavo-convex portion (3). A fire-resistant insulated cable comprising a heat-foamable fire-resistant paint (4). 2. The depth of the recess (3a) is 0.3 to 5.0 mm.
The fireproof insulated cable according to claim 1. 3. A fireproof insulated cable according to claim 1, wherein a skin layer (5) is formed by covering the entire outside of the heat-foamable fireproof paint (4). 4. The fireproof insulated cable according to claim 1, wherein the heat-foamable fireproof paint (4) further contains fireproof fibers.