JPH11306891A - Laminated mica tape for fire resisting wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce weight and improve high-temperature insulating characteristic, without increasing the number of turns or the thickness by setting the substantial average thickness of mica flakes constituting a laminated mica part to a specified value or less. SOLUTION: As mica flakes 3 constituting a laminated mica part 2, those crushed by a crusher capable of remarkably finely crushing natural mica or synthetic mica with a substantial average particle size of 45-170 μm are used. The substantial average thickness of the mica flakes 3 is set to 2 μm (0.1-2 μm) or less. Since the high-temperature insulating characteristic is sharply improved according to this, the number of turns onto a conductor circumference can be minimized. Thus, the outer diameter of the resulting fire resisting wire can be minimized to reduce the weight, and the manufacturing cost can be also reduced. Furthermore, the airtightness of the reconstituted mica part 2 is improved, so that the penetration of a cracked gas causing reduction in insulation in a high-temperature insulation test can be strongly prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mica scale formed by pulverizing natural mica or synthetic mica to form a mica scale, and affixing a reinforcing material such as glass cloth using a silicone resin or the like as an adhesive. The present invention relates to a mica tape for fire-resistant electric wires formed in combination.

[0002]

2. Description of the Related Art Conventionally, for a fire-resistant electric wire specified by, for example, a notice of the Fire and Disaster Management Agency, the following high-temperature insulation resistance and withstand voltage are measured by a sample A shown in FIG.

[0005] In FIG. 5, a sample A is composed of two refractory wires D in which a mica tape for refractory wire (hereinafter simply referred to as “mica tape”) C is wound around a conductor B having a conductor diameter of 2 mm by about 1/2 lap winding twice. The two refractory wires D are brought into parallel contact with each other, and a vinyl chloride sheet E is wrapped around the outer periphery of the two refractory wires D by one-half wrap, and the outer periphery of the vinyl chloride sheet E is pressed and wound with a mica tape F. .

The sample A shown in FIG.
Under the specified load specified in the aforementioned Fire Service Notification, etc.,
While applying AC600 V in an electric furnace, JISA130
In accordance with the indoor fire temperature curve specified in Section 4 (Fire prevention test method for non-combustible structures in buildings), the temperature rises from room temperature to 840 ° C in 30 minutes, and during this time, the refractory wire D maintains a high-temperature insulation resistance of 0.4 MΩ or more. Further, after heating, it is required to have a withstand voltage of AC 1.5 KV or more.

Therefore, conventionally, in order to satisfy the above requirements, the laminated mica tape 11 constructed as shown in FIG.
Was used. That is, in FIG. 3, reference numeral 12 denotes an assembled mica portion formed by pulverizing mica scales 13 obtained by pulverizing natural mica or synthetic mica. The reinforcing member 14 such as a glass cloth is bonded.

In the conventional mica tape 11 constructed as described above, the thickness m ₁ of the mica assembly 12 shown in FIG. 3 is about 105 μm. The thickness h ₂ of the reinforcing member 14 is about 3
Since the thickness of the mica tape 11 is 5 μm,
Was about 140 μm.

The conventional laminated mica tape 11
The aggregated mica part 12 of the mica scale 13 shown in FIG. 4 is substantially average particle diameter d of 45 to 1700 μm,
When the average is taken, the particle size d is 300 μm (in this specification, “substantially average particle size d is 1700 μm” means that “substantially the average particle size d is 1700 μm or more. 1/2 means that the particle diameter d is substantially less than 1700 μm is about 1/2 ”(the same applies hereinafter).

In addition, the practical average thickness t of the mica scale 13
Is 2 to 7 μm, and when the average thereof is taken, the thickness t is 4 μm.
μm (in the present specification, “substantially the average thickness t is 7 μm”).
“m” means that “substantially the thickness t is 7 μm or more is about 、, and that the thickness t is substantially less than 7 μm is about」 ”. Yes. The same applies hereinafter.)

Therefore, the number n of laminated mica scales 13 in the laminated mica portion 12 of the conventional laminated mica tape 11 is such that the thickness m ₁ of the laminated mica portion 12 is 105 μm.
Is divided by the average thickness t = 4 μm of the mica scale 13 to obtain about 26 sheets. Therefore, the leakage path LP indicated by the broken line in FIG. 4 is given by the following equation (1): LP = (n−1) d / 2 + nt─── (1) The calculated path LP is about 3854 μm.

Thus, the conventional mica tape 11 constructed as shown in FIG.
It is used in a 1/2 mm wrap around a 2.0 mm conductor.

The conventional laminated mica tape 11
5 was prepared using a fire-resistant electric wire using the above method, and under a predetermined load determined by the Fire and Disaster Management Agency notice or the like, while applying AC600V in an electric furnace, according to the indoor fire temperature curve described above. The temperature is raised from room temperature to 840 ° C. for 30 minutes while maintaining a high-temperature insulation resistance of 0.4 MΩ or more,
Further, after the heating, it was designed to have a withstand voltage of AC 1.5 KV.

[0012]

However, in recent years, in order to guarantee higher security, the AC1.5
In some cases, a performance that can withstand a high voltage significantly higher than KV is required, and on the other hand, an insulating material whose weight is further reduced is required, and the high-temperature insulating property required for the insulating material is further improved. Is required.

By the way, in order to manufacture a refractory wire capable of withstanding a high voltage significantly higher than the above-mentioned AC 1.5 KV using a normal mica tape, it is necessary to increase the thickness of the mica part or to increase the thickness of the mica part. Conventionally, a method of increasing the number of turns of the mica tape has been generally considered.

However, both of these methods have the disadvantage that the outer diameter of the refractory wire becomes large, which goes against the above-mentioned demand for weight reduction, and that the production cost becomes high. The present invention has been made by paying attention to the above points, and the object thereof is to reduce the thickness of the mica scales constituting the assembled mica portion, and for fire-resistant electric wires capable of withstanding the high voltage. It is an object of the present invention to provide a laminated mica tape, thereby reducing the weight of a fire-resistant wire and improving high-temperature insulation properties.

[0015]

According to the present invention, in order to achieve the above-mentioned object, a silicone resin or the like is bonded to a laminated mica portion formed by forming mica scales obtained by pulverizing natural mica or synthetic mica. In the mica tape for fire-resistant electric wire which is made by bonding reinforcing material such as glass cloth as an agent,
It is characterized in that the mica scales constituting the mica aggregate part have a substantially average thickness of 2 μm or less.

[0016]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. 1 is a sectional view showing a configuration of a laminated mica tape refractory wire according to the present invention, FIG 2 is X ₁ arrow radical 113 enlarged cross-sectional view shown in FIG.

In the figure, reference numeral 1 denotes an assembled mica tape, 2 denotes an assembled mica portion, 3 denotes a mica scale, 4 denotes a reinforcing material such as glass cloth, and 5 denotes an adhesive such as a silicone resin. [First Embodiment] Next, a first embodiment of the present invention will be described in detail.

The structure of the mica tape 1 shown in FIG.
Mica scale 3 obtained by crushing natural mica or synthetic mica
Is formed by bonding a reinforcing material 4 such as a glass cloth to the lower surface of the mica portion 2 formed by sheeting with an adhesive 5 such as a silicone resin. This structure is different from the conventional structure shown in FIG. with the same, and its laminated mica thickness h ₁ of the mica paper portion 2 of the tape 1 is about 105 .mu.m, the thickness h ₂ of the reinforcement 4 of the glass cloth or the like bonded by an adhesive 5 is about 35μm Therefore, the thickness H of the assembled mica tape 1 is about 140 μm, which is the same as the conventional one.

However, the mica scale 3 constituting the laminated mica part 2 of the first embodiment of the present invention is obtained by pulverizing natural mica or synthetic mica with a pulverizer capable of remarkably finely pulverizing. The mica scale 3 has a substantially average particle diameter d of 45 to 170 μm, and when the average is taken, the particle diameter d is 120 μm (in this specification, “substantially average particle diameter d is 170 μm”). Is described as “substantially having a particle diameter d of 170 μm or more is about 1 /
2. Substantially 1/2 having a particle size d of less than 170 μm ”
(The same applies hereinafter).

The mica scale 3 has a substantially average thickness t.
Is 0.1 to 2 μm, and the average is the thickness t.
1.0 μm (in this specification, “substantially average thickness t is 2 μm” means that “substantially thickness t is 2 μm”.
m is about 1/2, and the thickness t is substantially less than 2 μm is about 1/2 ”(the same applies hereinafter).

Therefore, the number n of the mica scales 3 laminated in the mica part 2 of the mica tape 1 is determined by the thickness h ₁ = 105 μm of the mica part 2 and the average thickness t = 1.0 of the mica scale 3. Calculated by dividing by
It is about 105 sheets.

Therefore, when the leakage path LP indicated by a broken line in FIG. 2 is calculated by the above equation (1), LP = 6345
μm, and the conventional mica unit 12 shown by a broken line in FIG.
About 60% longer than the leakage path LP.

Therefore, by using the mica tape 1 of the first embodiment of the present invention, the high-temperature insulation resistance can be improved without increasing the number of windings or increasing the thickness.

Using the mica tape 1 of the first embodiment of the present invention, the sample A shown in FIG. 5 was manufactured in the same manner as in the prior art, and the sample A was heated in an electric furnace in the same manner as described above.
The temperature was raised to 0 ° C and the high-temperature insulation resistance was measured.
MΩ, compared to the conventional 0.4 MΩ,
The high temperature insulation resistance has been significantly improved.

The measurement result of the dielectric breakdown voltage after the temperature rise is as follows:
Since it was 4.1 KV, it was greatly improved compared to the conventional 2.4 KV. [Second Embodiment] Next, a second embodiment of the present invention will be described.

[0026] Thus, different from the present invention the second embodiment and the first embodiment, the thickness h ₁ of the mica part 2 shown in FIG. 1, although the first embodiment is approximately 105μm On the other hand, the second embodiment is the same as the first embodiment except for the point of about 65 μm.

[0027] Therefore, in the present invention h ₁ of the mica part 2 shown in Figure 1 of the second embodiment is about 65 .mu.m, h ₂ of the reinforcing material 4 was bonded with an adhesive 5, as in the first embodiment About 3
Since the thickness is 5 μm, the thickness H of the mica tape 1 is about 100 μm.

Thus, the mica scale 3 constituting the aggregated mica portion 2 has a substantially average particle size d of 120 μm,
The mica scale 3 is substantially the same as the first embodiment in that the average thickness t of the mica scale 3 is 1 μm, but the number m of laminated mica scales 3 in the aggregated mica portion 2 is the thickness of the aggregated mica portion 2 h ₁ = 65 μm, the average thickness t of the mica scale 3
= 1.0 μm, it is about 65 sheets.

Therefore, the leakage path LP indicated by the broken line in FIG. 2 is calculated to be 3905 μm when the mica unit 2 of the second embodiment is calculated by the above-mentioned equation (1). Then, using the mica tape 1 of the second embodiment of the present invention, the sample A of FIG. 5 was manufactured in the same manner as in the prior art, and the sample A was heated to 840 ° C. in an electric furnace in the same manner as described above. and, as a result of measuring the high-temperature insulation resistance during its heating, the ones of the present invention the second embodiment, despite the thickness h ₁ of the laminated mica portion 2 are significantly thinner than the conventional, Although it was 0.4 MΩ which was almost the same as the conventional one, the measurement result of the dielectric breakdown voltage after the temperature rise was 2.6 KV, which was greatly improved as compared with the conventional one.

Table 1 below shows a conventional mica tape assembly and
The measured values of the high-temperature insulation resistance during the temperature rise and the dielectric breakdown voltage after the temperature rise are shown by the configuration dimensions, the leakage path, and the sample A shown in FIG. 5 in the first and second examples.

[0031]

[Table 1]

As is apparent from Table 1, those of the first embodiment although mica portion thickness h ₁ is the same as that of the conventional leakage path LP is improved significantly compared with the conventional high temperature insulation It is shown that the resistance and the dielectric breakdown voltage after the temperature rise are significantly improved as compared with the conventional one. Next, according to the second embodiment of the present invention, the thickness m
₁ is 105 μm in the prior art, whereas 65 μm in the second embodiment, the leakage path and the high-temperature insulation resistance during the temperature rise are significantly reduced despite the extremely thinness.
It is almost the same as the conventional case, and it is shown that the dielectric breakdown voltage after the temperature rise is greatly improved as compared with the conventional case.

In the first and second embodiments of the present invention, the adhesive 5 such as silicone resin shown in FIG.
Epoxy resin, Alkit phenol, polyamide, polyimide, polyethylene, or the like may be used instead of the silicon resin (these are collectively referred to as “silicone resin or the like” in this specification).

In the first and second embodiments of the present invention, the reinforcing material 4 such as a glass cloth shown in FIG.
Instead of a glass cloth, a polyester film, a polyester nonwoven fabric, a polyester woven fabric, a polyamide film, a polyimide film, a polyethylene, or the like may be used (in the present specification, these are collectively referred to as “glass cloth or the like”).

[0035]

As is clear from the above description, according to the present invention, the mica scales composed of mica scales having a substantially average thickness of 2 μm or less have the following excellent effects.

(A) As in the first embodiment of the present invention, when the thickness of the mica assembly is made the same as that of the conventional one, the high-temperature insulation characteristics are remarkably improved. Therefore, the number of windings on the outer periphery of the conductor can be reduced as compared with the conventional case, and the outer diameter of the refractory wire can be reduced, so that the weight can be reduced and the manufacturing cost can be reduced.

(B) As in the second embodiment of the present invention, even if the thickness of the mica assembly is thinner than that of the conventional one, the high-temperature insulation characteristics can be made almost the same as the conventional one. Even if the number of turns around the conductor wire is the same as the conventional one, the outer diameter of the fire-resistant wire can be reduced, thereby reducing the weight of the fire-resistant wire and reducing the manufacturing cost. Can be done.

(C) The laminated mica tape according to the present invention comprises:
As described above, the purpose is to reduce the weight of the refractory wire and to improve the high-temperature insulation properties. However, as described above, the average thickness of the mica scales constituting the assembled mica portion is set to 2 μm or less. As a result, the airtightness of the mica assembly is improved, and the invasion of a decomposition gas, which causes insulation deterioration during a high-temperature insulation test, can be prevented much more strongly than in the past, so that the durability characteristics of the high-temperature insulation are improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a mica tape according to an embodiment of the present invention.

2 is an enlarged sectional view of the X ₁ arrow radical 113 shown in FIG.

FIG. 3 is a cross-sectional view showing the structure of a conventional mica tape of this type.

It is an enlarged sectional view of the X ₂ arrows radical 113 shown in FIG. 3; FIG.

FIG. 5 is a partial cross-sectional side view of a sample used for a high-temperature insulation resistance test of a fire-resistant wire.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Mica tape 2 ... Mica part 3 ... Mica scale 4 ... Reinforcing material such as glass cloth 5 ... Adhesive such as silicone resin

Claims (1)

[Claims] 1. A fire-resistant electric wire obtained by bonding a mica scale formed by pulverizing natural mica or synthetic mica to form a mica scale and bonding a reinforcing material such as a glass cloth with a silicone resin or the like as an adhesive. A mica tape for a fireproof electric wire, wherein the mica scales constituting the mica laminated part have a substantially average thickness of 2 μm or less.