JPH09213138A - Electric wire and cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric wire and cable which has superior rat proofing effects and flame resistance and is easily manufactured by using flame resistant composite using acetal copolymer as a base polymer for a rat proofing layer and containing red phosphorus. SOLUTION: A cable is so constituted that a plurality of insulating wire cores 3 formed by coating a conductor 1, which is composed of copper and aluminium, with insulating bodies 2 such as polyethylene and cross-linked polyethylene are stranded with each other, and a flame resistant sheath 5 composed of flame resisting vinyl chloride resin, flame resisting polyolefin, etc., and a rat proofing layer are provided around the outer circumference via an inclusion 4 such as paper. The rat proofing layer is so formed that a flame resistant composite using acetal copolymer as a base polymer and containing red phosphorus is extruded and coated on the sheath 5. The bending elastic modulus of the acetar copolymer is preferable to be 4000kgf/cm<2> or mare and the bending elastic modulus in the last composite is more preferable to be 8000-10000kgf/cm<2> .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire / cable having both rodent-proof property and flame-retardant property.

[0002]

2. Description of the Related Art Electric wires and cables used in buildings and underground malls are required to have flame retardancy from the viewpoint of disaster prevention measures, and those using flame-retardant materials for covering materials such as sheaths are generally used. There is. On the other hand, in recent years, the number of reports of food damage due to such rods of electric wires / cables has been increasing, and there is a possibility of causing serious accidents such as abnormal operation or stoppage of equipment.

By the way, as a technique for imparting rod-proof property to electric wires / cables, there is a method of mechanically protecting the electric wires / cables by blending a repellent agent in the sheath and winding a metal tape such as stainless tape. Is generally known. Further, recently, a method of providing a coating made of a polymer having high mechanical strength has been devised.

[0004]

However, the use of repellents has some problems in terms of long-term sustainability of effects. Further, the method of winding the metal tape has a drawback that the flexibility of the electric wire / cable is lowered and the manufacturing process is complicated. On the other hand, the method of coating a polymer having high mechanical strength does not complicate the production and also has a good long-term sustainability of the rodent-proof effect. However, on the other hand, since the polymer is flammable, there is a problem that the flame retardancy is lowered. Therefore, still
The fact is that no electric wire / cable having excellent anti-mouse effect and flame retardancy, which is useful as an electric wire / cable to be laid in a building or the like, has been obtained.

The present invention has been made in view of such conventional circumstances, and provides an electric wire / cable which has both excellent rodent-proof effect and flame retardancy and is easy to manufacture. To aim.

[0006]

An electric wire / cable of the present invention is characterized by comprising an acetal copolymer as a base polymer and a rodent-proof layer made of a flame-retardant composition containing red phosphorus. To do.

In such an electric wire / cable, since the rodent-proof layer has a rodent-proof effect excellent in long-term sustainability and also has excellent flame retardancy, the electric-wire / cable has these characteristics. Moreover, the production is easy because the flame-retardant composition may be extrusion-coated, and the flexibility of the electric wire / cable is not impaired as in the case of winding a metal tape.

[0008]

Embodiments of the present invention will be described below.

FIG. 1 is a cross sectional view showing an example of an embodiment of the present invention.

As shown in FIG. 1, this cable has a plurality of insulating cores 3 (in FIG. 1, a conductor 1 made of copper, aluminum or the like and an insulator 2 made of polyethylene, cross-linked polyethylene or the like coated on the conductor 1. 2 pieces) are twisted together, and a flame-retardant sheath 5 made of flame-retardant vinyl chloride resin, flame-retardant polyolefin, etc. and a rodent-proof layer 6 are sequentially provided on the outer circumference of these two layers with an intervening member 4 made of paper or the like. ing.

The rodent-proof layer 6, which is a feature of the present invention, comprises a flame-retardant sheath 5 containing a flame-retardant composition containing an acetal copolymer as a base polymer and containing red phosphorus.
It is formed by extrusion coating on top.

The acetal copolymer used herein has the general formula

Embedded image The copolymer (polyacetal) represented by is a copolymer of comonomer components such as oxyethylene group and oxybutylene group. Its mechanical strength and rigidity are slightly lower than those of homopolymers. The flexibility is superior to that of the homopolymer, and the rodent-proof layer 6 has excellent rodent-proof effect. From the viewpoint of the rodent-proof effect, use of a homopolymer, that is, polyacetal is conceivable, but as described above, it is not suitable as a coating material for electric wires / cables due to its poor flexibility. In the present invention, it is particularly preferable to use an acetal copolymer having a flexural modulus of 4000 kgf / cm ² or more, and if it is less than 4000 kgf / cm ² , the rodent-proof effect may be insufficient. More preferably, it is an acetal copolymer having a flexural modulus of the final composition in the range of 8000 to 10000 kgf / cm ² , and specifically, DURACON (trade name) manufactured by Polyplastics Co. is suitable. used.

Red phosphorus imparts excellent flame retardancy to the rodent-proof layer 6. That is, since the acetal copolymer has an oxygen atom in the molecule, it is extremely flammable, but by adding red phosphorus, flame retardancy can be imparted. This is due to the effect that red phosphorus reacts with oxygen to generate polymetaphosphoric acid, which forms a nonvolatile protective film to block oxygen, and the flame-retardant effect of the carbon film produced by the dehydration reaction by polymetaphosphoric acid. Conceivable. This red phosphorus is an acetal copolymer.
It is desirable to mix 3 to 30 parts by weight per 100 parts by weight.

In the present invention, by blending melamine powder with such red phosphorus, the flame retardancy can be further enhanced, and further, a halogen flame retardant and / or an antimony flame retardant can be blended. As a result, even more excellent flame retardancy can be imparted. Examples of halogen-based flame retardants include chlorine-based flame retardants such as chlorinated paraffin and perchlorocyclopentadecane, bromine-based flame retardants such as hexabromobenzene and ethylenebistetrabromophthalimide, and three antimony-based flame retardants. Examples thereof include antimony oxide and antimony pentoxide.

When the melamine powder is blended, the mixing ratio with red phosphorus is approximately 1: 1 by weight, and the total amount thereof is in the range of 5 to 50 parts by weight per 100 parts by weight of the acetal copolymer. desirable. The blending amount of melamine powder is
The desired high flame retardancy cannot be obtained even if the amount is too much or too little compared to red phosphorus. Further, if the total amount of these is less than 5 parts by weight per 100 parts by weight of the acetal copolymer, the effect of imparting flame retardancy becomes insufficient, and conversely, if it exceeds 50 parts by weight, the mechanical properties deteriorate.

The amount of halogen-based flame retardant and / or antimony-based flame retardant compounded is preferably in the range of 3 to 30 parts by weight per 100 parts by weight of acetal copolymer.

In addition to the above-mentioned components, the flame-retardant composition constituting the rodent-proof layer 6 may, if necessary, be a colorant, an antioxidant, an ultraviolet ray, etc. within a range not impairing the effects of the present invention. You may mix | blend an absorber, a lubricant, and other additives.

Further, the layer thickness of the rodent-proof layer 4 made of such a flame-retardant composition is preferably about 0.4 to 1.0 mm in view of the rodent-proof effect and economical efficiency.

In the cable thus constructed, the acetal copolymer is used as the base polymer and the rodent-proof layer 6 made of the flame-retardant composition containing red phosphorus is contained, so that an excellent rodent-proof that lasts for a long time is obtained. In addition to having the effect, it also has excellent flame retardancy. Further, in manufacturing, a special process such as winding a metal tape is not required, and the flexibility of the cable is not impaired. Therefore, it is very useful as a cable installed in a building.

The above-described example is an example in which the present invention is applied to a cable having a structure in which a plurality of insulated wire cores 3 are twisted and a flame-retardant sheath 5 is provided on the outer periphery thereof, but the present invention is not limited to this. The present invention is not limited to such an example, and although not shown, the present invention can be applied to an electric wire / cable of various structures including an insulated electric wire in which a conductor is covered with an insulator. If necessary, another protective coating may be provided on the outer periphery of the rodent-proof layer 6.

[0021]

EXAMPLES Next, specific examples of the present invention will be described.

Example 1 ^Two insulated wire cores having an outer diameter of about 3 mm, which are made by coating an insulator made of polyvinyl chloride on a copper conductor having a cross-sectional area of 1.25 mm 2, are twisted together, and an intervening paper is added to the outside thereof. The flame-retardant polyvinyl chloride resin composition was extrusion coated to form a 1.1 mm-thick sheath, and then 100 parts by weight of acetal copolymer (DURACON) was added and mixed with 20 parts by weight of red phosphorus. The flame-retardant composition thus obtained was extrusion-coated to form a rat-proof layer having a thickness of 0.4 mm (final outer diameter of about 9.5 mm).

Example 2 A cable was manufactured in the same manner as in Example 1 except that the thickness of the rodent-proof layer was 0.3 mm.

Examples 3 and 4 Cables were manufactured in the same manner as in Example 1 except that the compounding ingredients of the material for forming the rodent-proof layer and the compounding amounts were changed as shown in Table 1.

The obtained cables of the respective examples were subjected to a food damage test with a mouse and a vertical tray burning test according to IEEE std.383 to evaluate the rodent resistance and flame retardancy. The results are shown in Table 1.

The food damage test is about 1.5 after capturing outdoors.
The brown rats, which have been kept indoors for a month, are placed in a cage containing a 10 cm long sample cable along with a solid feed for breeding and breeding mice and rats (product name CE-2 manufactured by CLEA Japan, Inc.) and water, and after 2 days have passed. It was observed with the naked eye whether or not the sample cable of FIG.

For comparison with the present invention, Table 1 shows an example in which the rodent-proof layer was formed of only the acetal copolymer (Comparative Examples 1 and 2), and a composition in which melamine powder was mixed with the acetal copolymer. Example formed (Comparative Example 3), Example formed with a composition containing another flame retardant in an acetal copolymer (Comparative Example 4), formed with a flame-retardant polyvinyl chloride resin composition containing a repellent (naramycin) The example (Comparative Example 5) was also shown.

[Table 1] As is clear from Table 1, the cable according to the present invention has both a rodent-proof effect and a flame retardant property, and particularly has a high rodent-proof property when the thickness of the rodent-proof layer is 0.4 mm. It was confirmed.

[0028]

As described above, the electric wire / cable of the present invention has a constitution in which the acetal copolymer is used as the base polymer and the rat-proof layer made of the flame retardant composition containing red phosphorus is provided. In addition, it has an excellent anti-mouse effect and flame retardancy, and the manufacturing process is not complicated, and the characteristics such as flexibility are not deteriorated. Therefore, it is extremely useful as an electric wire or cable laid in a building or the like.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of an electric wire / cable of the present invention.

[Explanation of symbols]

 1 ... Conductor 2 ... Insulator 3 ... Insulation wire core 4 ... Interposition 5 ... Flame-retardant sheath 6 ... Rat-proof layer

Claims (3)

[Claims] 1. An electric wire / cable comprising an acetal copolymer as a base polymer and a rodent-proof layer made of a flame-retardant composition containing red phosphorus. 2. The flexural modulus of the acetal copolymer is 4
The electric wire / cable according to claim 1, wherein the electric wire / cable is 000 kgf / cm ² or more. 3. The electric wire / cable according to claim 1, wherein the flame-retardant composition contains melamine powder.