JPH11317116A - Electromagnetic wave shield material, and electromagnetic wave shield sheet, wire and cable, and cable cover using this - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve each characteristic of sound insulation, impact resistance and vibration isolation, and to facilitate the manufacture at a low cost to an enlarged object by adding a specified quantity of conductive carbon and carbon fiber to a plastic material. SOLUTION: This shield material is obtained by adding conductive carbon to a plastic material in the ratio of 35-65 pts.wt. to 100 pts.wt. of the plastic material, and also adding carbon fiber in the ratio of 10-40 pts.wt. To this shield material, 4-16 pts.wt. of sulfur is added to 100 pts.wt. of the plastic material, whereby the plastic material can be formed into a more stable and uniform conductive material, so that the electromagnetic wave shield effect can be more improved in a high frequency band. In this shield material, further, 3-30 pts.wt. of zinc oxide is added to 100 pts.wt. of the plastic material, whereby an uniform and sure conductive material can be provided, so that a shield body excellent in sound insulation, impact resistance and vibration isolation can be easily manufactured at a low cost.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic wave shielding material for shielding electromagnetic waves, and more particularly to an electromagnetic wave shielding material formed of plastic, an electromagnetic wave shielding sheet made of the electromagnetic wave shielding material, and an electromagnetic wave shielding material. Wires and cables to be covered,
And a cable cover made of the electromagnetic wave shielding material.

[0002]

2. Description of the Related Art In recent years, electronic devices have been constructed with digital circuits, and have been operated with very small signal currents due to power saving due to high integration of various components in the devices. A so-called Electromagnetic Interference (E), in which the signal current of a device is disturbed by an electromagnetic wave generated by the device or an interfering electromagnetic wave from another electronic device.
MI) is more likely to occur. Electromagnetic waves (noise) that cause this EMI include conductive noise that flows through circuits and wiring of electronic devices and radiation noise that propagates in the air. In general, conductive noise can be removed by interposing a filter or the like in the circuit.However, for radiated noise, an electromagnetic wave that covers the target electronic device with a conductive material and prevents the electromagnetic wave from passing inside and outside You need to shield. As a method of this conventional electromagnetic wave shielding, use of a conductive composite plastic molding material, conductive surface treatment,
There is use of metal materials.

The use of the conductive composite plastic molding material is a method of integrally molding a casing having a predetermined shape using a molding material obtained by mixing a conductive filler in an ABS resin, a polypropylene resin, a nylon resin, or the like. As this conductive filler, conductive carbon, carbon fiber, metal flake,
There are metal fibers and the like.

[0004] The conductive surface treatment is a method of coating a conductive film on the front surface or the back surface of a housing for accommodating electronic equipment or the like to be subjected to EMI. The conductive film is formed by spraying zinc, applying a conductive paint mixed with a powder of nickel or carbon, or vacuum-depositing aluminum or the like.

The metal material is a metal foil or a laminate sheet of a metal foil and a plastic film, and is mainly used as a partial shield for parts and joints to cover a noise source.

[0006] On the other hand, cables used to connect electronic devices as wiring in the electronic device or outside the electronic device are often exposed to external radiation noise together with the conductive noise. In addition, an electromagnetic wave, that is, radiation noise has been generated from a cable or an electric wire by itself when a current flows. Conventionally, this cable uses a filter such as a ferrite core to remove conductive noise generated due to radiated noise and conductive noise transmitted directly from equipment. It prevented the generation of electromagnetic waves from itself.

In addition, electric wires such as high-voltage wires that do not have a metal foil or a metal braid around the conductor as a shield are not often affected by external electromagnetic waves, but generate electromagnetic waves from the wires themselves. Was being radiated around.

[0008]

Since the conventional electromagnetic wave shielding has been performed as described above, when a conductive composite plastic molding material and a metal material are used, they are manufactured in a shape that shields the entire building or room. There is a problem that it is technically difficult to perform the method, and the production cost increases. In addition, conventional conductive materials have a problem that sufficient sound insulation properties and shock absorption properties cannot be obtained.

In particular, it is difficult to shield an electromagnetic wave on an object such as an automobile, a vehicle, an airplane, or the like where vibrations may occur, with the conventional conductive material satisfying sufficient vibration proof and vibration proof characteristics. Was.

In addition to the above, in the case of using a filter such as a ferrite core in a conventional electromagnetic wave shield for a cable, the shield performance is often insufficient because the filter is partially used, and an extra filter is required. A large space is required, and there is a problem that it is difficult to use a wiring cable inside an electronic device that is generally required to be miniaturized.

In the case of a shielded cable, since a metal braid or a metal foil must be provided in the cable, the structure is complicated, the productivity is not good, and the manufacturing cost is high. Then, in order to perform electromagnetic shielding that blocks both the effects of electric and magnetic fields, it is necessary to add not only a conductive material but also a magnetic material to the shield material, which further complicates the structure and increases the cost. Had issues.

Further, a method of covering the entire cable or electric wire with the above-mentioned conductive composite plastic molding material or metal material to secure electromagnetic wave shielding can be considered, but the conductive composite plastic molding material or metal material can be applied to the cable or electric wire. However, it is difficult to manufacture such a shape, and the manufacturing cost is high. In addition, it is difficult to obtain sufficient flexibility in each case, and it is difficult to mount the device on a cable or an electric wire. In particular, in the case of a thin cable, there is a problem that it is difficult to form the cable into a predetermined thin diameter which does not impair the space-saving property in a state where the material satisfies sufficient flexibility and insulation with the core wire. .

On the other hand, in the case of electric wires such as high-voltage wires, although electromagnetic waves are generated from the wires themselves, no electromagnetic wave shielding is performed at all since no metal foil or metal braid as a shield is provided around the conductor. There has been a concern about the effect of the generated electromagnetic waves on the surrounding environment.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is an electromagnetic wave shielding material which is excellent in sound insulation, impact, and vibration isolation characteristics and can be manufactured easily and at low cost for a large object. In addition, the electromagnetic wave shielding sheet made of the shielding material, the electromagnetic wave shielding material is formed integrally with the core wire as a jacket, so that no extra space is taken,
It is another object of the present invention to provide an electric wire / cable that can be easily manufactured at low cost and has excellent handleability, and a cable cover made of an electromagnetic wave shielding material.

[0015]

According to the present invention, there is provided an electromagnetic wave shielding material comprising a plastic material to which 35 to 65 parts by weight of conductive carbon is added to 100 parts by weight of the plastic material, and 10 to 40 parts by weight. The carbon fiber is added at a ratio of parts. As described above, according to the present invention, a conductive material and a carbon fiber are added to a plastic material at a predetermined ratio to make the plastic material a stable and uniform conductive material, thereby covering an object such as an electronic device. If it is used as a shield, it has electromagnetic wave shielding properties for electromagnetic waves in a wide frequency band from low frequency to high frequency equivalent to an electromagnetic wave shield of a metal plate, and particularly shields electromagnetic waves in a high frequency band that causes EMI In addition to being able to do so, it is excellent in sound insulation, shock, and vibration isolation characteristics, and can easily and inexpensively produce a shield, and can cope with a large object without any problem.

The electromagnetic wave shielding material according to the present invention is characterized in that the plastic material is
Sulfur is added at a ratio of 4 to 16 parts by weight with respect to 0 parts by weight. As described above, according to the present invention, by adding sulfur in a predetermined ratio to a plastic material that has become a conductive material by adding conductive carbon, the plastic material is made more stable and uniform, and the electromagnetic wave shielding effect is obtained. Can be further improved in a high frequency band.

Further, the electromagnetic wave shielding material according to the present invention is such that zinc white is added to the plastic material at a ratio of 3 to 30 parts by weight with respect to 100 parts by weight of the plastic material as required. As described above, according to the present invention, by adding zinc white to a plastic material at a predetermined ratio, the plastic material can be made more uniformly and reliably a conductive material, and each characteristic of sound insulation, impact, and vibration isolation can be improved. An excellent shield can be manufactured easily and at low cost.

Further, in the electromagnetic wave shielding sheet according to the present invention, the electromagnetic wave shielding material is formed into a substantially sheet-like body having a predetermined shape, and a large number of holes having a predetermined shape penetrate the substantially sheet-like body at predetermined intervals. It is formed. As described above, according to the present invention, when a large number of holes are formed at predetermined intervals in an electromagnetic wave shielding material formed into a substantially sheet shape, the electromagnetic wave shielding performance can be improved when covering an object such as an electronic device as a shield. In addition to ensuring heat dissipation, heat can be dissipated from inside by allowing ventilation inside and outside, eliminating the need for special mechanisms and devices for heat dissipation, and reducing the weight by forming holes. Cost reduction can be achieved as a whole.

Further, in the electromagnetic wave shielding sheet according to the present invention, if necessary, the substantially sheet-like body is formed in a substantially rectangular shape, and has a first shape of a predetermined shape which is circumferentially continuous with two adjacent sides. A joining portion is formed, and a second joining portion having a predetermined shape is formed on the remaining two sides of the periphery so as to join the first joining portion to continuously connect the substantially sheet-like bodies integrally. . As described above, according to the present invention, the first sheet-like body and the second joint part which can be joined to each other are formed around each other, so that a plurality of electromagnetic wave shielding sheets are arranged side by side. In this case, it can be arranged without creating a gap between each sheet, and the shielding performance can be maximized without weakening even at the joints, and multiple electromagnetic wave shielding sheets provide uniform shielding effect over a wide range Given. In addition, even when the electromagnetic wave shielding material has directionality, the directionality is kept constant without misalignment so that the first joint and the second joint are joined without contradiction between adjacent substantially sheet-like bodies. They can be arranged side by side, and a shielding effect can be reliably obtained.

Further, in the electromagnetic wave shielding sheet according to the present invention, the above-mentioned substantially sheet-like body is formed with different colors on the front and back as required. As described above, according to the present invention, by changing the color of the front and back sides of the substantially sheet-like body so that the front and back sides can be easily distinguished, if the shielding performance is slightly different between the front side and the back side, they are arranged in the correct direction. As a result, the desired shielding performance can be reliably obtained.

Further, the electric wire / cable according to the present invention is formed by covering one or more core wires with the electromagnetic wave shielding material. Thus, according to the present invention,
By coating the core wire with an electromagnetic wave shielding material based on a plastic material, it is possible to shield electromagnetic waves, especially electromagnetic waves in a high frequency band, only with a jacket made of the electromagnetic wave shielding material, thereby not impairing flexibility and saving space. In addition, it can be manufactured easily and at low cost.

The electric wire / cable according to the present invention may be, if necessary, a metal having an electromagnetic wave absorbing property in a ratio of 50 to 230 parts by weight based on 100 parts by weight of the plastic material. The compound is added with fine short fibers. As described above, according to the present invention, by adding a predetermined amount of fine short fibers of a metal compound having an electromagnetic wave absorbing property to a plastic material, a high frequency from a low frequency similar to the case of an electromagnetic wave shield made of a plate of a metal compound is increased. Effective electromagnetic wave shielding characteristics can be demonstrated in all frequency bands up to the frequency,
At the same time, sufficient flexibility can be secured.

Further, the electric wire / cable according to the present invention may be provided, if necessary, in addition to the electromagnetic wave shielding material, another non-conductive plastic material may be coated on the core to form an electromagnetic wave shielding material and the other plastic material. Cover the core wire in layers. Thus, according to the present invention, the form of the cable jacket is a multi-layer structure of another plastic material layer and an electromagnetic wave shielding material layer,
By arranging a layer of another plastic material on the outermost layer or innermost layer, it is possible to ensure insulation between the core and the outside made of another plastic material, and there is no need to consider special insulation for the cable. Cable can be used safely in any location.

Further, the electric wire / cable according to the present invention is such that the electromagnetic wave shielding material covers the core wire in a layer in a state sandwiched between two layers of another plastic material as necessary. . As described above, according to the present invention, by forming the cable jacket into a three-layer structure in which the electromagnetic wave shielding material layer is sandwiched between different plastic materials, the outermost layer and the innermost layer are formed of the different electromagnetic wave shielding material portions. The cable can be reliably insulated from the core wire and the outside.There is no need to consider special insulation for the cable.The cable can be used safely at any point, and the outermost layer can be used for construction work. Even when removed, safety can be ensured without passing the current on the core wire side.

In the electric wire / cable according to the present invention, if necessary, the electromagnetic wave shielding material is laminated in a plurality of layers with different directions to cover the core. As described above, according to the present invention, a non-uniform state of the electromagnetic wave shielding property due to the directionality at the time of manufacturing is eliminated by forming a laminated structure in which the two electromagnetic wave shielding material layers are arranged with different directions. The influence can be reduced, the electromagnetic wave shielding property can be more reliably exhibited, and the electromagnetic wave attenuating effect can be increased as compared with a single electromagnetic wave shielding material having the same thickness.

In the cable cover according to the present invention, a conductive filler is added to the plastic material to provide conductivity, and sulfur is added at a ratio of 4 to 16 parts by weight with respect to 100 parts by weight of the plastic material. The formed electromagnetic wave shielding material is formed into a substantially tubular shape and surrounds the outer periphery of one or more electric wires or cables. As described above, according to the present invention, an electromagnetic shielding material formed by adding a predetermined amount of sulfur while adding a conductive filler is formed in a tubular shape to cover an electric wire or a cable. It is possible to shield electromagnetic waves that have an external influence, or that are generated from electric wires or cables and affect the surroundings, particularly electromagnetic waves in a high frequency band.

Further, the cable cover according to the present invention is formed in a substantially tubular shape by laminating one or more layers of another non-conductive plastic material on the electromagnetic wave shielding material as required. Thus, according to the present invention,
Considering special insulation for wires and cables that perform electromagnetic shielding by securing the outer and inner insulation of the cable cover structure as a multi-layer structure of another plastic material layer and an electromagnetic wave shielding material layer It is not necessary and can be used safely for any wire and cable.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment of the Present Invention) Hereinafter, an electromagnetic wave shielding material according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a composition example No. in the electromagnetic wave shielding material according to the present embodiment. 1 to No. 1 4 and FIG. 3 is an electromagnetic wave shield characteristic diagram, and FIG. FIG. 4 is an electromagnetic wave shielding characteristic diagram of FIG. 3 is an electromagnetic wave shielding characteristic diagram, and FIG. FIG. 4 is an electromagnetic shielding characteristic diagram of FIG.

Each of the formulation examples No. 1 to No. 3 of the electromagnetic wave shielding material according to the present embodiment. 1 to No. 1 No. 4 is a structure formed by adding a conductive agent to a plastic material as a basic material to provide conductivity, and adding a predetermined amount of sulfur or zinc white as needed.

As the plastic material, a thermoplastic polyester resin which is a kind of a thermoplastic resin which can be easily molded by press molding, injection molding, extrusion molding or the like is used. Thermosetting resins and engineering plastics such as polyamide resins and polycarbonates can also be used.

The conductive agent is conductive carbon and carbon fiber. The conductive material has an appropriate shielding effect, and the mixing and kneading operation can be carried out smoothly. The conductive carbon is added at a rate of 35 to 65 parts by weight (hereinafter, phr; par hundred resin) and the carbon fiber is added at a rate of 10 to 40 phr based on 100 parts by weight of the plastic material. The sulfur is added to the plastic material at a rate of 4 to 16 phr, and the zinc white is added at a rate of 3 to 30 phr. Further, a plasticizer, a stabilizer, and the like may be added to the plastic material in addition to the additives.

Each of the above Formulation Examples No. 1 to No. 1 The combinations and mixing ratios of the respective materials in No. 4 are shown below (see FIG. 1). First, Formulation No. 1 is an oil furnace black (Ketjen Black E manufactured by Lion Corporation) as the conductive carbon in the plastic material.
C) is added at a ratio of 40 phr and carbon fiber (fiber length 24 mm) is added at a ratio of 40 phr.

Next, Formulation No. 2 is the formulation example N
o. In addition to the composition of No. 1, the composition is such that zinc flower No. 3 is added to the plastic material at a rate of 5 phr and sulfur is added at a rate of 12 phr. In addition, Formulation Example No. 3
Is the above-mentioned formulation example No. In No. 1, the conductive carbon is added to the plastic material at a rate of 50 phr, and sulfur is added to the plastic material at a rate of 12 phr.

In addition, Formulation Example No. No. 4 is the formulation example N
o. No. 3 is a composition in which Zinc Hua No. 3 is added to the plastic material at a ratio of 5 phr instead of sulfur. The molding of the electromagnetic wave shielding material of each of the above blending examples is performed by first winding and kneading a thermoplastic polymer on a rotating rough kneading roller, and mixing zinc white first when using zinc white for the wound polymer. Conductive carbon, then sulfur if sulfur is used, and finally carbon fiber. While mixing, mill back on the rolls so that the mixture is well dispersed in the polymer. After a certain thickness, cut out from the roll to form a sheet. The sheet was pressed by applying a predetermined press temperature and pressure to obtain a sheet-like sample. The thickness of the sample is 4 mm.

FIGS. 2 to 5 show the results of evaluating the electromagnetic wave shielding characteristics by placing the electromagnetic wave shielding material of each of the above formulation examples in an environment where electromagnetic waves are generated. The degree of the electromagnetic wave shielding effect of these electromagnetic wave shielding materials depends on the incident electric field (magnetic field) from the front side of the sample and the electric field (magnetic field) after transmission to the back side.
And the decay rate, which is the ratio of Here, 0-1
The attenuation rate characteristics for electromagnetic waves in the frequency range of 000 MHz are being investigated. The obtained characteristics are shown in a graph with the horizontal axis representing the frequency of the electromagnetic wave (MHz) and the vertical axis representing the attenuation rate (dB).

As shown in FIG. In 1,
It can be seen that the attenuation rate is lower than −30 dB in almost all the frequency bands on the graph, and that the electromagnetic wave shielding effect can be obtained in a high frequency band of several hundred MHz.

As shown in FIG. Formulation No. 1 in which zinc white and sulfur were added to No. 1 In Formulation No. 2, although there is almost no difference in the attenuation characteristics with respect to the electric field, Formulation Example No. Since the damping effect on the magnetic field is slightly better than that of No. 32, it is understood that the shielding effect can be improved by adding one or both of zinc white and sulfur.

As shown in FIG. No. 3, the electromagnetic wave shielding characteristics are shown in Formulation No. 1 and No. 1 2
In comparison with the above, the damping effect is improved in a band of 200 MHz or more for an electric field and 600 MHz or more for a magnetic field.
Since the attenuation rate is lower than B, it can be seen that the electromagnetic wave shielding effect at a high frequency of several hundred MHz band can be significantly increased by increasing the amount of conductive carbon added.

Further, as shown in FIG.
In the above-mentioned formulation example No. 4, Since the attenuation effect is slightly weaker in the higher frequency band than that of No. 3, even if zinc white is added without adding sulfur, the electromagnetic wave shielding performance cannot be improved, and zinc white can be combined with sulfur. It can be seen that the electromagnetic wave shielding performance can be affected.

As described above, an electromagnetic wave shielding material obtained by adding conductive carbon, carbon fiber, sulfur, and zinc white to a plastic material at a predetermined mixture ratio is several hundred MHz.
In addition to obtaining a predetermined electromagnetic wave shielding effect in such a high frequency band, it can be easily formed into various shapes by using a plastic material as a base, and is lightweight, low-cost, and excellent in handleability.

(Second Embodiment of the Present Invention)
The electromagnetic shielding sheet according to the embodiment will be described with reference to FIGS. FIG. 6 is a schematic configuration diagram of the electromagnetic wave shielding sheet according to the present embodiment, and FIG. 7 is an explanatory diagram of the electromagnetic wave shielding sheet according to the present embodiment.

The electromagnetic wave shielding sheet 1 according to the present embodiment is made by adding a plurality of types of conductive agents (reinforcing agents) to a plastic material as a basic material so as to provide conductivity and to add a predetermined amount of sulfur. The shield material is formed in a sheet shape.

The electromagnetic wave shielding sheet 1 is formed as a substantially square thin sheet body having a large number of circular holes 2 penetrating from the front to the back at predetermined intervals in the front, rear, left and right directions, and forms a half of a peripheral portion. A first joint portion 3 having a substantially stepwise vertical cross-sectional shape is formed on two adjacent sides, and a substantially reverse stepwise shape that can be engaged with the first joint portion 3 on the other two sides of the other half of the peripheral portion. The second joining portion 4 is formed, and further, it is configured to be formed with different colors on the front and back.

Since the holes 2 allow ventilation on the front side and the back side, when covering an object such as an electronic device as a shield, heat can be radiated from the inside while sufficiently securing electromagnetic wave shielding performance. This eliminates the need for a special mechanism or contrivance for heat radiation in the object, reduces the weight of the sheet by the amount of the holes 2, and reduces the cost as a whole.

When a plurality of electromagnetic wave shielding sheets 1 are arranged side by side, as shown in FIG.
And the second joint portion 4 are brought into close contact with each other, so that a gap having a weak shielding effect does not occur between the sheets, and a plurality of electromagnetic wave shielding materials provide a uniform shielding effect over a wide range. Can be Furthermore, even if the shielding performance differs depending on the direction of the electromagnetic wave shielding material (there is a directivity), if a sheet having a constant relationship between the directionality and the sheet peripheral portion is used, the first joining portion is formed between the adjacent sheets in the front, rear, left and right directions. By arranging the sheets 3 side by side so that there is no contradiction between the engagement of the second joint portion 3 and the second joint portion 4, a uniform shielding effect can be obtained by keeping the directionality of each sheet constant. In addition, although the shape of the said 1st joining part 3 and the 2nd joining part 4 is formed in step shape, other shapes, for example, as shown in FIG. As shown in FIG. 7C, a structure in which the surface is formed as an inclined surface may be employed.

In addition to these, the electromagnetic wave shielding sheet 1
By changing the color of the front and back, even when using materials with different electromagnetic wave shielding characteristics on the front and back, the front and back can be easily identified and arranged in the correct direction without error, and the desired shielding performance can be achieved. Can be obtained reliably.

In the electromagnetic shielding sheet according to the above-described embodiment, the holes are formed as circular holes. However, the present invention is not limited to this, and may have any shape such as a square or a polygon.

(Third Embodiment of the Present Invention)
The cable according to the embodiment will be described with reference to FIG.
FIG. 8 is a schematic configuration explanatory view of the cable according to the present embodiment.

In the cable 5 according to this embodiment, a plurality of types of conductive agents (reinforcing agents) are added to a plastic material as a basic material to provide conductivity, and a predetermined amount of sulfur and zinc white are added. The electromagnetic wave shielding material to be formed is used as the jacket 6 to cover the core wire 7. The conductive agent is conductive carbon and carbon fiber, and is added to the plastic material in an amount that can smoothly perform the mixing and kneading operation and does not hinder product processing. Further, a softening agent, a processing aid, an antioxidant, an accelerator and the like are added to the plastic material as the basic material. Further, if necessary, a predetermined short amount of a metal compound fine short fiber such as ferrite having electromagnetic wave absorbing properties is added. The cable 5 can be obtained by coating the core wire 7 with the electromagnetic wave shielding material having such a composition as a single jacket material.

The cable 5 formed by coating the core wire 7 with the electromagnetic wave shielding material obtained by adding each of the above-mentioned compounding agents at a predetermined mixing ratio, shields electromagnetic waves in a high frequency band such as several hundred MHz, and reduces noise level. Can be reduced.

As described above, in the cable according to the present embodiment, the sheath made of the electromagnetic wave shielding material based on the plastic material makes the cable less susceptible to external electromagnetic waves and generates the cable itself. The electromagnetic wave that absorbs the electromagnetic wave is suppressed, and the emission to the outside is suppressed, the cable can be prevented from becoming a noise source, and no extra space is required like a filter. The flexibility is hardly impaired and the handleability is excellent. In the cable of the above embodiment, the core is configured as a multi-core insulated wire, but may be a single-core insulated wire or a bare wire.

(Fourth Embodiment of the Present Invention) The fourth embodiment of the present invention
The cable according to this embodiment will be described with reference to FIG. FIG. 9A is a cross-sectional view of the cable according to the present embodiment.

The cable 5 according to the present embodiment is
In the same manner as in the first embodiment, as the jacket 6 covering the core wire 7, a plastic material is supplied with sulfur, conductive carbon, carbon fiber, zinc white, a softener, an antioxidant, a vulcanization accelerator, etc. in a predetermined amount, respectively. The electromagnetic wave shielding material having conductivity obtained by addition is used. The difference is that the structure of the outer cover 6 is a two-layer structure of a general plastic material having no conductivity and an electromagnetic wave shielding material. The inner layer has a configuration in which a general plastic material is disposed in the outer layer.

As described above, in the cable according to the present embodiment, the outer jacket 6 has the two-layer structure of the general plastic material layer and the electromagnetic wave shielding material layer, so that the outer layer 6 is formed of a general plastic material. The insulation of the cable can be ensured, and there is no need to consider special insulation for the cable, and the cable can be safely used alone at any location.

(Fifth Embodiment of the Present Invention) The fifth embodiment of the present invention
The cable according to this embodiment will be described with reference to FIG. FIG. 9B is a schematic configuration sectional view of the cable according to the present embodiment.

The cable 5 according to the present embodiment is provided with the third
In the same manner as in the first embodiment, as the jacket 6 covering the core wire 7, a plastic material is supplied with sulfur, conductive carbon, carbon fiber, zinc white, a softener, an antioxidant, a vulcanization accelerator, etc. in a predetermined amount, respectively. Electromagnetic wave shielding material having conductivity obtained by addition is used. The difference is that the structure of the jacket 6 is such that a general plastic material having no conductivity is used as the innermost layer, and the electromagnetic wave shielding material is used as the intermediate layer. A general plastic material having no conductivity is disposed in the outermost layer, and has a three-layer structure in which a shielding material layer is sandwiched between general plastic material layers.

As described above, in the cable according to the present embodiment, the outer jacket 6 has a three-layer structure in which the electromagnetic wave shielding material layer is sandwiched between the general plastic material layers, so that the outermost general plastic material is formed. Insulation with the outside can be ensured, and there is no need to consider special insulation for the cable, and the cable can be used safely at any point by itself, and the electromagnetic wave shielding material layer and the inner core wire 7 can be connected. Can be insulated reliably.

(Sixth Embodiment of the Present Invention) The sixth embodiment of the present invention
The cable according to this embodiment will be described with reference to FIG. FIG. 10A is a cross-sectional view of the cable according to the present embodiment.

The cable 5 according to the present embodiment is
In the same manner as in the first embodiment, as the jacket 6 covering the core wire 7, a plastic material is supplied with sulfur, conductive carbon, carbon fiber, zinc white, a softener, an antioxidant, a vulcanization accelerator, etc. in a predetermined amount, respectively. An electromagnetic wave shielding material having conductivity obtained by addition is used. The difference is that the structure of the outer cover 6 is such that a general plastic material having no conductivity is arranged in the innermost layer and the outermost layer, and the intermediate layer is used as an intermediate layer. The electromagnetic wave shielding material is arranged in two layers with different directions, and has a configuration of four layers with two electromagnetic wave shielding material layers sandwiched between general plastic material layers.

As described above, in the cable according to the present embodiment, the two-layered electromagnetic wave shielding material layer sandwiched between the general plastic material layers is formed as a four-layered jacket 6 with different directions. This can eliminate the non-uniform state of the electromagnetic wave shielding property due to the directionality and reduce the influence thereof, and can more reliably exert the electromagnetic wave shielding property and increase the electromagnetic wave attenuation effect.

(Seventh Embodiment of the Present Invention) The seventh embodiment of the present invention
The cable according to this embodiment will be described with reference to FIG. FIG. 10B is a schematic configuration sectional view of the cable according to the present embodiment.

The cable 5 according to the present embodiment is
In the same manner as in the first embodiment, as the jacket 6 covering the core wire 7, a plastic material is supplied with sulfur, conductive carbon, carbon fiber, zinc white, a softener, an antioxidant, a vulcanization accelerator, etc. in a predetermined amount, respectively. An electromagnetic wave shielding material having conductivity obtained by addition is used. The difference is that the structure of the jacket 6 is such that the electromagnetic wave shielding material having different directions is arranged in the inner layer and the outer layer, respectively. It has the structure which becomes.

As described above, in the cable according to the present embodiment, the two electromagnetic wave shielding material layers are arranged in the two-layered structure with the directions changed from each other, so that the electromagnetic wave shielding material according to the directionality is formed. Can compensate each other by compensating for the non-uniform state of the electromagnetic wave shielding property in each layer, and compared with the jacket 6 of the third embodiment having the same thickness.
Electromagnetic wave shielding can be more reliably exerted, and the electromagnetic wave attenuation effect can be increased.

(Eighth Embodiment of the Present Invention) The eighth embodiment of the present invention
The cable cover according to the embodiment will be described with reference to FIG. FIG. 11 is a schematic configuration explanatory view of the cable cover according to the present embodiment.

The cable cover 8 according to the present embodiment is similar to the jacket 6 of the cable 5 according to the third embodiment, except that a plastic material is made of sulfur, conductive carbon, carbon fiber, zinc white, softener, aging. It has a configuration in which a substantially tubular body is formed by using a conductive electromagnetic shielding material obtained by adding predetermined amounts of an inhibitor, a vulcanization accelerator, and the like. Inside the cable cover 8, an electric wire 9 to be subjected to electromagnetic wave shielding is housed.

As described above, in the cable cover 8 of the present embodiment, the substantially tubular body having the electromagnetic wave shielding property based on the plastic material makes the cable cover 8 less susceptible to external electromagnetic waves and also stores the stored electric wires. 9
It also absorbs electromagnetic waves generated by itself and suppresses emission to the outside, prevents wires and cables from becoming a noise source, and does not require extra space like filters etc.
In addition, multiple wires and cables can be collectively shielded,
Excellent handleability.

In the cable cover according to the above-described embodiment, the electric wire 9 is housed inside, and the electromagnetic wave radiated from the electric wire 9 to the outside or the electromagnetic wave from the outside toward the electric wire 9 is shielded. , In addition to this,
Tubes of insulating material such as rubber or plastic can be passed through the inside, and the static electricity on the tube surface can be released outside through the conductive electromagnetic shielding material of the cable cover. It is possible to prevent the generation of electrostatic sparks due to electrification due to friction with the insulating material or the like, thereby ensuring safety against a flammable atmosphere or a flammable substance passing through the pipe.

[0068]

As described above, in the present invention, by adding conductive carbon and carbon fiber at a predetermined ratio to a plastic material to make the plastic material a stable and uniform conductive material, electronic equipment and the like can be obtained. If it is used as a shield that covers the target object, it has electromagnetic wave shielding characteristics against electromagnetic waves in a wide frequency band from low frequency to high frequency equivalent to the electromagnetic wave shielding material formed of a metal plate, especially EMI In addition to being able to shield electromagnetic waves in the high frequency band that causes it, it also has excellent sound insulation, shock, and vibration proof characteristics, and can manufacture shields easily and at low cost.
This has the effect of being able to respond to a large object without any problem. Further, in the present invention, by adding sulfur in a predetermined ratio to a plastic material that has become a conductive material by adding conductive carbon, the plastic material is made more stable and uniform, and the electromagnetic wave shielding effect is enhanced. This has the effect that it can be further improved in the frequency band. Further, in the present invention, by adding zinc white to the plastic material at a predetermined ratio, the plastic material can be more uniformly and reliably made a conductive material, and has excellent sound insulation, shock, and vibration isolation characteristics. This has the effect that the shield can be manufactured easily and at low cost. Further, in the present invention, by forming a large number of holes at predetermined intervals in an electromagnetic wave shielding material formed in a substantially sheet shape, when covering an object such as an electronic device as a shield, the electromagnetic wave shielding performance is ensured. In addition, the internal and external ventilation can be performed and heat can be dissipated from the inside, eliminating the need for a special mechanism or device for heat dissipation, and reducing the weight by forming the holes. This has the effect of reducing costs. Further, in the present invention, the plurality of electromagnetic wave shielding sheets are arranged side by side by forming the first sheet joint and the second sheet joint that can be joined to each other around the substantially sheet-like body. In addition, it can be arranged without creating a gap between each sheet, the shielding performance can be maximized without weakening even at the joint, and multiple electromagnetic shielding sheets can provide a uniform shielding effect over a wide range . In addition, even when the electromagnetic wave shielding material has directionality, the directionality is kept constant without misalignment so that the first joint and the second joint are joined without contradiction between adjacent substantially sheet-like bodies. The shield effect can be obtained reliably because they can be arranged side by side. Further, in the present invention, by changing the color of the front and back of the electromagnetic wave shielding material so that the front and back can be easily distinguished, if the shielding performance is slightly different between the front and back, the electromagnetic wave shielding material can be arranged in the correct orientation. This has the effect that desired shielding performance can be reliably obtained. In addition, in the present invention, by covering the core wire with an electromagnetic wave shielding material based on a plastic material, it becomes possible to shield electromagnetic waves, particularly electromagnetic waves in a high frequency band, only with a jacket made of the electromagnetic wave shielding material, thereby increasing flexibility. This has the effect that it is not damaged, the space can be saved, and it can be manufactured easily and at low cost. Further, in the present invention, by adding a predetermined amount of fine short fibers of a metal compound having an electromagnetic wave absorbing property to the plastic material, from a low frequency to a high frequency similar to the case of the electromagnetic wave shielding body made of a metal compound plate body The effective electromagnetic wave shielding characteristics can be exhibited in all the frequency bands described above, and at the same time, there is an effect that sufficient flexibility can be secured. Further, in the present invention, by forming the cable jacket into a multi-layered structure of another plastic material layer and an electromagnetic wave shielding material layer, another plastic material layer is arranged as the outermost layer or the innermost layer, and the cable jacket is formed separately. The insulation between the core and the outside made of the plastic material can be ensured, and there is no need to consider special insulation for the cable, and the cable can be safely used alone at any location. In the present invention,
By forming the cable jacket into a three-layer structure sandwiching the electromagnetic wave shielding material layer with another plastic material, the outermost layer and the innermost layer of another plastic material allow the electromagnetic wave shielding material part to be securely connected to the core wire and the outside. It is insulated, so there is no need to consider special insulation for the cable, and the cable can be used safely at any point alone, and even if the outermost layer is removed during construction work, etc. This has the effect of ensuring safety without passing current. In addition, in the present invention, a non-uniform state of the electromagnetic wave shielding property due to the directionality at the time of manufacturing is eliminated by forming a laminated structure in which two electromagnetic wave shielding material layers are arranged with different directions. Can be reduced, the electromagnetic wave shielding property can be more reliably exhibited, and the effect of attenuating electromagnetic waves can be increased as compared with a single layer of electromagnetic wave shielding material having the same thickness. Further, in the present invention, an electromagnetic shielding material formed by adding a predetermined amount of sulfur while adding a conductive filler is formed in a tubular shape to cover the electric wire or cable, so that the electric wire or cable can be externally applied. It has an effect that it can shield electromagnetic waves that have an influence or affect the surroundings generated from electric wires or cables, especially electromagnetic waves in a high frequency band. Further, in the present invention, by securing the insulation between the outside and the inside of the cable cover structure as a multi-layer structure of another plastic material layer and an electromagnetic wave shielding material layer, the cable and the wire to perform electromagnetic wave shielding Therefore, there is no need to consider special insulation, and there is an effect that any wire or cable can be used safely.

[Brief description of the drawings]

FIG. 1 is a composition example No. 1 of an electromagnetic wave shielding material according to a first embodiment of the present invention. 1 to No. 1 4 is an explanatory diagram of each composition. FIG.

FIG. 2 is a composition example No. 1 of the electromagnetic wave shielding material according to the first embodiment of the present invention. 1 is an electromagnetic wave shield characteristic diagram of FIG.

FIG. 3 is a composition example No. of the electromagnetic wave shielding material according to the first embodiment of the present invention. 2 is an electromagnetic wave shield characteristic diagram of FIG.

FIG. 4 is a composition example No. of the electromagnetic wave shielding material according to the first embodiment of the present invention. 3 is an electromagnetic wave shield characteristic diagram of FIG.

FIG. 5 is a composition example No. of the electromagnetic wave shielding material according to the first embodiment of the present invention. FIG. 4 is an electromagnetic shielding characteristic diagram of FIG.

FIG. 6A is a plan view of an electromagnetic wave shielding sheet according to a second embodiment of the present invention. (B) is an essential part sectional view of an electromagnetic wave shielding sheet according to a second embodiment of the present invention.

FIG. 7A is an explanatory view showing a state in which electromagnetic shielding sheets are arranged side by side according to a second embodiment of the present invention. (B) is a joining partial cross-sectional view of another electromagnetic wave shielding sheet according to the second embodiment of the present invention. (C) is a junction partial sectional view of another electromagnetic wave shielding sheet according to the second embodiment of the present invention.

FIG. 8A is a schematic configuration perspective view of a cable according to a third embodiment of the present invention. (B) is a sectional view of a cable according to a third embodiment of the present invention.

FIG. 9A is a sectional view of a cable according to a fourth embodiment of the present invention. (B) is a sectional view of a cable according to a fifth embodiment of the present invention.

FIG. 10A is a sectional view of a cable according to a sixth embodiment of the present invention. (B) is a sectional view of a cable according to a seventh embodiment of the present invention.

FIG. 11 is a schematic configuration explanatory view of a cable cover according to an eighth embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 electromagnetic wave shielding sheet 2 hole 3 first joint 4 second joint 5 cable 6 jacket 7 core 8 cable cover 9 electric wire

Claims (13)

[Claims] 1. A plastic material, wherein conductive carbon is added at a ratio of 35 to 65 parts by weight with respect to 100 parts by weight of the plastic material, and carbon fiber is added at a ratio of 10 to 40 parts by weight. And electromagnetic wave shielding material. 2. The electromagnetic wave shielding material according to claim 1, wherein sulfur is added to the plastic material at a ratio of 4 to 16 parts by weight based on 100 parts by weight of the plastic material. material. 3. The electromagnetic shielding material according to claim 1, wherein zinc white is added to the plastic material at a ratio of 3 to 30 parts by weight based on 100 parts by weight of the plastic material. Electromagnetic wave shielding material. 4. An electromagnetic wave shielding material according to claim 1, wherein said electromagnetic wave shielding material is formed into a substantially sheet-like body having a predetermined shape, and holes having a predetermined shape penetrating said substantially sheet-like body are formed at predetermined intervals. An electromagnetic wave shielding sheet, which is formed in a large number. 5. The electromagnetic wave shielding sheet according to claim 4, wherein the substantially sheet-like body is formed in a substantially square shape, and has a first shape having a predetermined shape that is circumferentially continuous with two adjacent sides. And a second joining portion of a predetermined shape capable of joining the first joining portion and joining the substantially sheet-like bodies together integrally on the remaining two sides of the periphery. To shield electromagnetic waves. 6. The sheet for electromagnetic wave shielding according to claim 4, wherein the substantially sheet-like body is formed with different colors on the front and back sides. 7. An electric wire / cable formed by covering one or a plurality of core wires with the electromagnetic wave shielding material according to claim 1. Description: 8. The electric wire or cable according to claim 7, wherein the electromagnetic wave shielding material comprises a plastic material,
An electric wire / cable, characterized by adding 50 to 230 parts by weight of a fine short fiber of a metal compound having electromagnetic wave absorption to 100 parts by weight of the plastic material. 9. The electric wire / cable according to claim 7, wherein, together with the electromagnetic wave shielding material, another non-conductive plastic material also covers the core wire, and the electromagnetic wave shielding material and the another plastic material are covered. An electric wire or cable characterized in that the material covers the core wire in layers. 10. The electric wire / cable according to claim 9, wherein the electromagnetic wave shielding material covers the core wire in a layer in a state sandwiched between the two layers of the another plastic material. And electric wires and cables. 11. The electric wire / cable according to claim 7, wherein the electromagnetic wave shielding material is laminated in a plurality of layers with different directions to cover the core wire. Electric wires and cables. 12. A cable cover, wherein the electromagnetic wave shielding material according to any one of claims 1 to 3 is formed in a substantially tubular shape and surrounds one or a plurality of electric wires or cables. 13. The cable according to claim 12, wherein one or more layers of another non-conductive plastic material are laminated on the electromagnetic wave shielding material to form a substantially tubular shape. cover.