JPS622406B2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a termite-proof cable.

Conventionally, various termite-proof electric cables have been used to prevent damage to electric cables caused by termites and the like. These termite-proof cables include, for example, cables with a metal sheath or metal tape formed on the cable insulated core, cables with a nylon jacket formed on the cable sheath, or cables with high-density polyethylene or the like formed on the cable insulated core. Those equipped with a hard plastic sheath are used.

However, cables formed with metal sheaths or metal tapes are hard and difficult to bend, making them difficult to handle during construction work such as installation work, and increasing the price of the cables. In addition, in this type of electric cable, the metal sheath or metal tape itself is not damaged by termites, but if the rubber or plastic anti-corrosion layer of the outer sheath of the metal tape or metal sheath is damaged, the metal sheath or metal tape It also has the disadvantage that it is attacked by corrosive action. Further, the electric cable formed with a nylon jacket is hard and difficult to bend and has poor handling efficiency. Another drawback is that special techniques and equipment are required to form the nylon jacket, which increases the cost. Furthermore, electric cables equipped with hard plastic sheaths are hard and inconvenient to handle, and must be extruded at high temperatures using a large extruder to form the hard plastic sheath. There are drawbacks such as being subject to various practical restrictions.

This invention was made in view of the above circumstances,
With the aim of providing a termite-proof cable that is easy to handle, does not require special manufacturing equipment, and is not susceptible to termite damage, the compound represented by the following formula, (In the formula, R represents an alkyl group) An anti-termite layer made of a composition contained in a rubber composition or synthetic resin composition having a molding temperature below the thermal decomposition temperature of this compound is provided on the outside or inside of the cable sheath. It is characterized by this.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 shows an example of the termite-proof cable of the present invention, and reference numeral 1 in the figure indicates the termite-proof cable of the present invention. This anti-termite cable 1 is composed of three insulated wire cores 2, 2, 2, a sheath 4 covering these insulated wire cores 2, 2, 2, and an anti-termite layer 5 provided on the outside of the sheath 4. has been done.

This anti-termite layer 5 is made of a nitrile rubber composition, a chloroprene rubber composition, a polyvinyl chloride resin composition plasticized with a plasticizer such as a phthalate ester or a fatty acid ester, or a polyethylene resin plasticized with a chlorinated paraffin. The composition is made of a rubber composition or synthetic resin composition with a molding temperature of 165°C or less, such as a composition mainly composed of low molecular weight polyvinyl chloride resin, and the compound represented by the above formula (1) is kneaded. is included. For example, when the alkyl group is an ethyl group, this compound
It is called diethyl O-3.5.6-trichloro-2-pyridyl-phosphorothioate, and is a type of so-called organophosphorus insecticide. In addition, when the alkyl group is a methyl group, O・O-dimethyl O
It is called -3,5,6-trichloro-2-pyridyl-phosphorothioate, and is also a type of organophosphorus insecticide. Here, the molding temperature of the rubber composition or synthetic resin composition was specified to be 165°C or less because the thermal decomposition temperature of the above compounds is about 165°C, and the above compounds are heated during the extrusion coating process of the termite-proof layer 5. This is to prevent the anti-termite properties from decreasing due to thermal decomposition caused by the heat treatment. The amount of these compounds in the anti-termite layer 5 is 0.05 to 20% by weight; if it is less than 0.05% by weight, the desired anti-termite effect cannot be obtained, and if it exceeds 20% by weight, the anti-termite layer 5 will not be formed. The mechanical and electrical properties of the rubber composition or synthetic resin composition deteriorate, which is disadvantageous.

In addition, the sheath 4 is made of a nitrile rubber composition, a chloroprene rubber composition, a polyvinyl chloride resin composition,
It is made of a common rubber composition such as a polyethylene resin composition or a synthetic resin composition. Since the termite-proofing layer 5 of the sheath 4 is formed of a rubber composition or a synthetic resin composition with a molding temperature of 165° C. or lower, its mechanical strength is inevitably low, so the termite-proofing cable 1
This was provided because it may not be able to sufficiently protect the equipment from mechanical damage, etc.

This anti-termite cable 1 provided with an anti-termite layer 5 containing such the above-mentioned compound exhibits a long-lasting and excellent anti-termite effect due to the above-mentioned compound contained in the anti-termite layer 5, and is prevented by termites etc. In addition to being free from corrosion damage, the internal insulated wire cores 2, 2, 2 are sufficiently protected by the internal sheath 4 having excellent mechanical strength.

FIG. 2 shows a second embodiment of the present invention, and the same components as those in FIG. 1 are given the same reference numerals and their explanations will be omitted. This example of termite-proof cable 1
consists of three insulated wire cores 2, 2, 2, an inner sheath 4 that covers these insulated wire cores 2, 2, 2, and an anti-termite layer that is a tape-wrapped layer provided on the outside of this inner sheath 4. 5, and an outer sheath 6 that covers this anti-termite layer 5. The anti-termite layer 5 is a tape formed from a rubber composition or synthetic resin composition containing the above-mentioned compound and having a molding temperature of 165° C. or less by a roll molding method, a calendar molding method, an extrusion molding method, or the like. This anti-termite layer 5 is wound around or longitudinally attached to the outside of the inner sheath 4. Further, the outer sheath 6 is made of the same ordinary rubber composition or synthetic resin composition as the inner sheath 4. Therefore, this example of termite-proof cable 1
is sufficiently mechanically protected by the outermost outer sheath 6 and the inner inner sheath 4, and at the same time, even if the outer sheath 6 is damaged by termites, it is protected by the inner termite-proof layer 5. This prevents the ant cable 1 from being eaten by the central part.

FIG. 3 shows a third embodiment of the present invention, and the same components as those in FIG. 1 are designated by the same reference numerals and their explanation will be omitted. This example of termite-proof cable 1
consists of three insulated wire cores 2, 2, 2, an anti-termite layer 5 formed by simultaneously wrapping the insulated wire cores 2, 2, 2 together with tape, and an anti-termite layer 5 that covers the anti-termite layer 5. It is composed of an outer sheath 6. The anti-termite cable 1 of this example is also protected by the external sheath 6 with high mechanical strength, and at the same time, even if the external sheath 6 is damaged by termites, the anti-termite layer 5 prevents the termite damage. It is prevented from advancing into the center of the cable 1.

As explained above, the termite-proof cable of the present invention is characterized by adding 0.05 to 20% of the compound represented by formula (1) to a rubber composition or synthetic resin composition having a molding temperature below the thermal decomposition temperature of the compound. An anti-termite layer made of an anti-termite composition kneaded and contained in the sheath is provided on the inside or outside of the sheath.
The above-mentioned compound does not undergo thermal decomposition during molding of the anti-termite layer, prevents the deterioration of the anti-termite effect, makes full use of the anti-termite effect of the above compound, and resists feeding damage by termites etc. over a long period of time. There is no. Furthermore, since the above-mentioned compound is simply contained in the anti-termite layer, the bendability and various properties of the cable are hardly impaired. Furthermore, since it can be manufactured using conventional electric cable manufacturing equipment as is without requiring any special manufacturing equipment or technology, it has the advantage of minimizing cost increases.

[Brief explanation of the drawing]

1 to 3 are sectional views showing examples of the termite-proof cable of the present invention. 2...Insulated wire core, 3...Sheath, 5...Ant-proof layer.

Claims (1)

[Claims] 1. General formula (In the formula, R represents an alkyl group.) A termite-prevention layer made of a rubber composition or synthetic resin composition in which 0.05 to 20% by weight of the compound represented by the formula is kneaded and whose molding temperature is below the thermal decomposition temperature of this compound is formed. An ant-proof cable characterized by being provided on the inside or outside of the sheath. 2. The termite-proof cable according to claim 1, wherein the alkyl group is a methyl group or an ethyl group.