JPS581145B2 - Conductive anisotropic rubber or plastic - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to novel rubbers and plastics having conductive anisotropy.

2. Description of the Related Art Conductive rubber formed by mixing a polymeric elastic material and conductive powder and molding the mixture is well known and is used as a non-chargeable rubber.

However, conventionally known conductive rubbers have high resistivity and poor rubber properties, and therefore, their properties have not been actively utilized, except for some special uses from the viewpoint of antistatic properties. It never happened.

Furthermore, anisotropically conductive rubbers and plastics that have particularly high conductivity in a specific direction and appropriate elasticity or hardness, and their usefulness have not been known.

The present invention has been made based on the above-mentioned viewpoints, and its purpose is to make a wide range of proposals regarding these anisotropic conductive rubbers or plastics, their manufacturing methods, uses, etc.

Therefore, the gist of the present invention is a rubber or plastic containing conductive fibers arranged in a certain direction, but the present invention can be implemented in combination with other components. For example, conductive rubber mixed with magnetic powder at the same time, reinforced sheets with core wires, cloth, or mesh, composite sheets with plating on both sides, or with metal foil, insulating film, etc. In addition, the product of the present invention is manufactured by laminating and rolling rubber or plastic fabric blended with conductive fibers in a fixed direction many times, vulcanizing or polymerizing, drying, heating, or cooling. However, by performing appropriate secondary processing after rolling and before these treatments, it can be made into plates, bands, wires, rods, pipes, hoses, etc.
It can be provided as a container, box, gasket, or other desired shaped molded product.

In the product of the present invention, the desired conductivity can be imparted without impairing the properties of rubber or plastic, particularly their flexibility, but rather by reinforcing the strength and elasticity of these materials. Since the conductivity is much higher than that of known conductive rubbers and it responds sharply to externally applied stress, the present invention has an extremely wide range of applications.

The structure, manufacturing method, uses, etc. of the conductive anisotropic rubber or plastic according to the present invention will be explained below with reference to the drawings.

FIGS. 1 and 2 are explanatory diagrams showing a method for manufacturing the product of the present invention, FIGS. 3 to 7 are partially cutaway perspective views showing various embodiments of the present invention, and FIG. and FIG. 9 are explanatory diagrams showing different usage examples of the product of the present invention, and FIGS. 10 to 12 are graphs showing examples of electromagnetic characteristics of the product of the present invention, respectively.

First, the explanation will be given sequentially starting from FIGS. 1 and 2.

In the figure, 1 and 1 are a pair of rolling rollers, 2 is a conductive fiber 3,
Conductive rubber dough 5 and 6 are rolled sheets made by kneading conductive rubber material 3 and raw rubber 4 mixed with an appropriate vulcanizing agent.

Therefore, inside the fabric 2, the conductive fibers 3, 3 are not oriented in a fixed direction and are electrically and mechanically isotropic, but once rolled by the rolling rollers 1, 1. When the sheet 5 is rolled, the conductive fibers 3, 3 tend to be oriented in the rolling direction (the y-axis direction in the figure).

As shown in FIG. 2, the sheets 5 are then stacked or folded and laminated and rolled again in the same direction.

In such a case, the directions of the conductive fibers 3, 3 are further made uniform inside the re-rolled sheet 6.

After repeating the same lamination rolling to make the direction of the conductive fibers 3, 3 uniform to a certain level, heating and vulcanization treatment are performed, mechanically as shown in Fig. 3. A conductive rubber sheet 7 having both electrical and electrical anisotropy is obtained.

In addition, the dough sheet 6 before vulcanization treatment is appropriately cut, punched,
After molding into the desired shape by stamping, pasting, etc.
It is also recommended to perform heating and vulcanization treatment.

As the conductive fiber, for example, carbon fiber or copper,
Aluminum and other ferromagnetic or nonmagnetic metal fibers, whiskers, etc. can be used, and instead of raw rubber, silicone rubber, soft vinyl chloride, polyethylene, and other synthetic resins can be used.

The conductive rubber sheet 7 shown in FIG. 3 shows the basic structure of the product of the present invention.

A feature of this sheet 7 is that the conductive fibers 3, 3 are arranged in parallel to the rolling direction inside the sheet 7, which allows for a smaller amount of conductive fibers compared to conventionally known sheets. This means that high conductivity, especially in the y-axis direction, can be obtained depending on the ratio.

Therefore, according to the present invention, sufficiently high conductivity can be imparted to the rubber or plastic at a small material cost, without significantly impairing the flexibility, elasticity, fatigue fracture strength, etc. of the rubber or plastic.

In addition, in this sheet 7, since the conductive fibers 3, 3 act as strong fillers, the tensile strength and toughness in the y-axis direction are greatly improved, but on the other hand, the tensile strength and toughness in the x-axis and z-axis directions are Elasticity and flexibility are not significantly affected.

In addition, if ultra-fine long fibers with a metallic luster are used as the conductive fibers 3 and 3, and transparent synthetic resin is used, a unique light effect will occur, resulting in beautiful conductive boards, films, etc. .

Another important characteristic of the product of the present invention is that the conductivity of these conductive rubbers or plastics changes sharply in response to external forces applied from various directions.

The sheet 7 having the basic structure shown in FIG. 3 can be used for a wide range of purposes depending on the above-mentioned properties, the rubber or plastic used, and the specific properties of the conductive fibers. be.

To give you a glimpse of it, first of all, there are materials that take advantage of its conductivity and mechanical strength, such as materials for non-static hoses, oil containers, belts, tank lining materials, flooring materials, etc., and materials using copper fibers. The use of conductive synthetic rubber as a shoe sole material not only increases durability, but also has the effect of preventing athlete's foot, preventing electric shock caused by static electricity, and preventing slipping, which is extremely advantageous.

Furthermore, the product of the present invention can be provided as a composite sheet or the like in which it is composited with other constituent materials, as shown in FIGS. 4 to 7.

In the sheet 8 shown in FIG.
Along with this, magnetic fine particles 9, 9 are blended.

The sheet 8 is rolled in a strong magnetic field parallel to the rolling direction, and as a result, these magnetic fine particles 9,
The easy magnetization axes of No. 9 are aligned in the rolling direction, that is, in the y-axis direction.

Similarly, the sheet 10 shown in FIG.
and is rolled in a strong magnetic field in the x-axis direction, so that the magnetic fine particles 9, 9 are arranged so that their easy magnetization axes are perpendicular to the sheet surface.

These sheets 8 and 10 are made of electromagnetic rubber and are widely used as force-magnetic conversion elements, magneto-resistance conversion elements, artificial muscles, etc.

The sheet 11 shown in FIG. 6 has a joint pattern 12 on its upper surface, a large number of parallel copper wires 13, 13 arranged in the center of its thickness, and a pressure-sensitive adhesive layer on its bottom surface. 14 and a backing paper 15, and a seventh
The sheet 16 shown in the figure has fine serrations 17 on its upper surface, a wire mesh 18 on its inside, and an aluminum foil 19 on its bottom.

FIG. 8 is an explanatory diagram showing an example of the use of the sheet 7 shown in FIG. 23 is the cargo to be transported, 24 to 27 are guide rollers, 28 is a constant voltage DC power source, and 29 is a circuit protection device. 30 is an ammeter.

As explained later in FIGS. 10 to 12, the resistance value of the belt between the guide rollers 25 and 26 changes sharply depending on the load weight of the cargo 23 on top of the belt. The indication on the ammeter 30 changes accordingly.

Therefore, by reading this indicated value, the load weight is known, and by integrating that value, the total conveyance amount is known.

Furthermore, FIG. 9 shows an example of the use of the sheet 16 shown in FIG.
8 and the aluminum foil 19, a DC power supply 32 is connected via a protective resistor 31, and a Schmitt trigger circuit 33 is connected to the wire mesh side terminal of the protective resistor 31, and its output signal is sent to the empty vehicle indicator. 34.

Therefore, when there is no load W on the seat 16, the wire mesh 18 is at a high potential, so the output of the Schmitt trigger circuit 33 is at a high level, and the empty vehicle indicator 34 is glowing, but the seat When a vehicle enters onto the 16 and a load W is generated, the resistance between the wire mesh 18 and the aluminum foil 19 decreases rapidly, so the output of the Schmitt trigger circuit 33 becomes low level and the empty vehicle indicator 34 disappears. It is something.

Further, in this embodiment, it is also possible to use a light emitting diode or the like instead of the protective resistor 31 to more directly display parking information.

It is also possible to use the sheet 11 shown in FIG. 6 for the same purpose as in this embodiment.

It is obvious that these sheets can also be applied to security alarms, passing vehicle counters, and the like.

Next, examples regarding the anisotropic electroconductive rubber according to the present invention will be shown.

Example 1 Carbon fiber 30V with a diameter of 1μ and a length of about 5μ is added to silicone raw rubber (dimethyl, silane, diol) with a polymerization accelerator.
Ba ferrite powder with ol% and particle size of 0.5μ 5Vol%
are blended and rolled repeatedly at 10 to 20 kg/cm2 until the direction of the carbon fibers is sufficiently aligned.

During rolling and subsequent polymerization and rubber elasticity processes, an external magnetic field of 3,000 Oe is applied perpendicular to the rolling surface to magnetize and align the Ba ferrite powder in the direction of the magnetic field.

A rubber sheet with a thickness of 3 mm was obtained as described above.

The anisotropy and pressure sensitive properties of the electroconductive rubber obtained as described above were as shown in FIGS. 10A to 10D.

10A is an x-axis direction magnetic flux density-compressive force characteristic diagram when compressive force is applied in the x-, y-, and z-axis directions, and FIG. 10B is also an x-axis direction resistivity-compressive force characteristic diagram, Similarly, C is a y-axis specific resistance-compressive force characteristic diagram, and D is a z-axis specific resistance-compressive force characteristic diagram.

Therefore, the magnetic flux density in the y-axis direction and the Z-axis direction was much smaller than the magnetic flux density in the x-axis direction shown in FIG. A, and could be considered to be substantially zero.

Example 2 The same materials as in Example 1 above were mixed in the following manner, and the same treatments as in Example 1 above were performed to obtain a rubber sheet with a thickness of 0.6 mm.

Carbon fiber blending ratio: 28 Vol% Ba ferrite blending ratio: 10 Vol% The anisotropy and pressure sensitive properties of the electromagnetic rubber thus obtained are the first.
It was as shown in Figure 1 A to D.

Therefore, Fig. 11 A, B, C, and D are compressive force characteristic diagrams corresponding to Fig. 10 A, B, C, and D, respectively, and the magnetic flux density in the y-axis direction and the z-axis direction is This was much smaller than the x-axis direction magnetic flux density shown in FIG. 3A, and could be considered to be substantially zero.

Example 3 Processed as in Example 2 using the following compounding ratio to obtain a thickness of 0.2
A rubber sheet of mm was obtained.

Carbon fiber blending ratio: 25 Vol% Ba ferrite blending ratio: 10 Vol% The X-axis direction magnetic flux density-compressive force characteristic diagram of this electroconductive rubber is shown in Figure 12A, and the Specific resistance-compressive force characteristic diagrams are shown in Figure 12 B, C and D, respectively.
It was as shown.

As is clear from the examples described above. Characteristics of these rubbers are that they have anisotropy in electrical conductivity and magnetism, and that these electrical conductivities and magnetisms are large and change extremely sensitively to compression from various directions.

To explain the data in Figures 10 to 12 more specifically, these electromagnetic rubbers have a high magnetic flux density in the x-axis direction, and the magnetic flux density is compressed in the x-, y-, and z-axis directions. It increases when a force is applied, but for compression in the y- and Z-axis directions, when the compressive force is 1 kg/cm2, the rate of increase in magnetic flux density (rate of increase relative to the magnetic flux density when the compressive force is 0, the same applies hereinafter) .

) increases by about 50 to 60%, whereas when compressed in the x-axis direction, it increases by about 200%, that is, about three times.

Therefore, the magnetic flux density in the y-axis direction and the z-axis direction was almost zero in both cases.

Regarding resistivity, the resistivity in the x-, y-, and z-axis directions all change hyperbolically with the compressive force from each direction, and the rate of change is almost unrelated to the direction of the compressive force. be.

Further, under the same compression conditions, the specific resistance values in the x-axis direction and the z-axis direction are approximately the same value, and both are about 1.5 to 3 times the specific resistance value in the y-axis direction.

In the above embodiments, only the compression of the electromagnetic rubber was explained, but it is obvious that the magnetic flux density and electrical resistance of these rubbers change not only by compression but also by tension, bending, or twisting.

Further, the above-mentioned magnetic flux density and electrical resistance vary greatly depending on the materials, dimensions, shapes, and blending ratios of the ferromagnetic powder and conductive fibers to be blended.

Note that the ferromagnetic powder to be blended as described above does not necessarily have to have a strong coercive force, and may be soft iron powder that does not become a permanent magnet.Furthermore, if a conductive fiber having ferromagnetism is used as the conductive fiber, An anisotropically conductive electromagnetic rubber different from that of the above embodiments is obtained.

Note that the magnetic flux density in the x-axis direction and the electric conductivity in the y-axis direction of these rubbers are both larger than those of known isotropic rubbers.

The conductive rubber according to the present invention has a wide range of useful uses other than the above-mentioned examples, and if put into practice, it can provide great industrial and consumer benefits.

[Brief explanation of the drawing]

FIGS. 1 and 2 are explanatory diagrams showing a method for manufacturing the product of the present invention, FIGS. 3 to 7 are partially cutaway perspective views showing various embodiments of the present invention, and FIGS. FIG. 9 is an explanatory diagram showing different usage examples of the product of the present invention, and FIGS. 10 to 12 are graphs each showing an example of the electromagnetic characteristics of the product of the present invention. 1, 1: rolling roller, 3, 3: conductive fiber, 2: raw rubber, 5, 6, 7, 8, 9, 10, 11, 16: conductive rubber sheet, 9: magnetic fine particles, 13: copper wire, 18: wire mesh, 14: pressure sensitive adhesive, 15: backing paper, 19: aluminum foil.

Claims (1)

[Claims] 1. In conductive rubber or plastic made by bonding fine conductor powder with rubber or plastic, the fine conductor powder is in the form of fibers, and the direction of the conductor fibers is aligned in a substantially constant direction. conductive anisotropic rubber or plastic characterized by a particularly low resistivity