JP2001089668A - Conductive thermoplastic elastomer composition and conductive member formed therefrom - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a material that is easy in molding and processing, has small electric resistance, and used for manufacturing a conductive member such as a bipolar plate for a fuel cell. SOLUTION: This conductive thermoplastic elastomer composition is formed by adding a conductive filler such as carbon to a vulcanized thermoplastic elastomer. By adding the conductive filler to a completely vulcanized thermoplastic elastomer, the conductive thermoplastic elastomer composition can remarkably increase the compounding amount of the filler and reduce electric resistance while keeping good toughness of the material and excellent thermoplastic operability.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a highly conductive thermoplastic elastomer composition and a conductive member formed from the composition.

[0002]

BACKGROUND OF THE INVENTION Conductive members are used in many applications, such as electrical connectors, wire and cable covers, flooring, and minimize static electricity, such as in the manufacture of computer chips and magnetic components. Used for applications that need to be. Another major use for conductive members is in devices, such as fuel cells, in which two or more substances are chemically combined in the presence of a diaphragm catalyst to convert chemical energy into electrical energy.

[0003] A fuel cell generates a continuous current directly from oxidation of a fuel (eg, a chemical reaction between hydrogen and oxygen) without burning the fuel. There are several types of fuel cells under development, including phosphoric acid, molten carbonate, solid oxide, and proton exchange membranes.
membrane. A PEM) method, an alkali method, a direct methanol method, and the like are known. Among these approaches, PEM fuel cells are being actively researched and developed by automakers as potential candidates for environmentally friendly automotive electrochemical power units. This is because PEM fuel cells have relatively high power density performance and almost zero emissions.

[0004] In general, a PEM fuel cell comprises a membrane electrode assembly (MEA) and a membrane electrode assembly (MEA).
It has channels formed in the bipolar plate on both sides facing the MEA. MEA is "Nafion" (trademark of Dupont)
And a proton conductive electrolytic membrane such as This electrolytic diaphragm is sandwiched between two electrodes. There are two thin catalyst layers between the electrode and the diaphragm. PEM fuel cells convert the chemical energy of the reactants into electrical energy. A typical example of a PEM fuel cell is described in US Pat. No. 5,260,143, the disclosure of which is incorporated herein.

The current of a PEM fuel cell is, inter alia, a function of the size of the active surface area (or current producing surface area) of the MEA.
Typically, a bipolar plate is provided with grooves (channels) formed on a flat, planar surface of an electrode plate by molding, machining, or embossing, so that a gaseous fuel (typically, Hydrogen flows through these channels to the anode side of the MEA, and gaseous oxidant (typically air or oxygen) flows through these channels to the cathode side. On the anode side, hydrogen dissociates into free electrons and protons. The free electrons are the base of the current, and the bipolar plate (or flow separator plate) from the anode side to the cathode side
To move. Protons pass through the MEA and combine with oxygen and free electrons to produce water.

In order to maximize the electrical efficiency of a fuel cell,
It is very important that free electrons can flow through the bipolar plate with minimal resistance. Bipolar plates known today cannot be easily molded from composite materials. The reason is that in order to minimize the electrical resistance, it is necessary to fill the material with a very high percentage of solids.

[0007] Another limitation of the known fuel cells is that grooves must be formed by machining or embossing flow passage plates formed of a chemically inert material.
Therefore, there is a demand for a bipolar plate which can be manufactured at low cost, is easy to manufacture, has excellent corrosion resistance, and has high conductivity.

[0008] Conductive materials have also been used in other applications such as electrical connectors, wires and cables, and flooring.
Also in these applications, it is required that the material can be manufactured at low cost, is easy to manufacture or mold, has excellent corrosion resistance, and has high conductivity.

[0009]

A solution to the above demand is to use a thermoplastic elastomer material which has high conductivity, is easy to process (work), has excellent corrosion resistance, and can be manufactured at low cost for a conductive member. Can be achieved.
More specifically, this problem can be solved by using a conductive vulcanized thermoplastic elastomer (TPV).

As is well known, a thermoplastic resin is a crystalline or semi-crystalline material having a relatively high glass transition temperature, such as graphite powder, carbon black powder, metal powder, or the like.
Thermoplastics can be made conductive by mixing conductive fillers such as carbon fibers or metal fibers (e.g., British Patent No. 1,495,275, US Patent No. 4,179,341, US Patent No. 4,510,078). U.S. Pat.No. 5,207,949; U.S. Pat.No. 5,322,874; U.S. Pat.
5,707,699).

However, there is a limit to the amount of filler that can be incorporated in order to keep both the mechanical and processing (working) properties of the material intact. For example, U.S. Pat. No. 4,569,786 specifically addresses this problem, and the combination of metal fiber and carbon fiber in less than 20% by weight of thermoplastic material does not impair ease of melt processing. It is disclosed. This amount is
Much more than replacing these fibers with the same type of powdered conductive filler. Such a composition with a high metal fiber loading is unsuitable for use in electrochemical fuel cells and other conductive components due to corrosion problems. U.S. Pat. No. 4,937,015 addresses the problem that conductive thermoplastics filled with large amounts of filler are inferior in processability and material properties. This reference teaches the use of thermoplastic particles and up to 20% by weight of a solid conductive material to form the material, while using pressure to form the electrode plate. However, the material manufactured by this method has a volume resistivity of 10 ³ Ω · cm.
The drawback is that it doesn't get smaller.

In order to improve the mechanical properties of a conductive thermoplastic resin to which a large amount of filler has been added, a crystalline elastomer material and an amorphous elastomer material (ie, a non-crystalline material having a low glass transition point) are used. Conventionally, a conductive filler is blended with the above-mentioned blend. US Patent 4,265,789
And U.S. Pat. No. 4,321,162 describe a flexible, melt-processable, conductive material based on a blend of an elastomeric low Tg (glass transition temperature) material and a crystalline high Tg material. I have. Target applications for this material are electrical connectors, cables, and other conductive moldings. In each case, none of the polymer phases is chemically crosslinked.

US Pat. No. 5,484,838 also describes the addition of carbon black to a blend of crystalline and amorphous materials, the use of which is suitable for electrostatic coating. It is intended for compositions. The volume resistivity of these materials is stated to be at least 10 ⁵ Ω · cm, and none of the polymer phases is chemically crosslinked.

Another approach to managing the electrical resistance of carbon black / polymer blends is to control processing conditions. U.S. Pat. No. 3,823,217 describes that the room temperature resistance of a carbon black / crystalline polymer blend is reduced by thermal cycling of the blend. U.S. Pat. No. 4,534,889 discloses a method of tuning a compounded composition of a conductive filler and a polymer to produce a material having controlled electrical properties, particularly electrical properties with respect to temperature, and such compositions. The device made of the object is described. The key to this method is to fill the elastomer phase with filler and then control the electrical properties through processing conditions and cure cycles. US Patent 5,
In 844,037, the control of the electrical properties of the polymer blend carbon black composition is performed by controlling the phase morphology and how the carbon black is dispersed between the different phases. Through all these prior arts, the conductive filler is dispersed within each polymer blend component.

None of the above prior art patents solves the problem of providing a highly conductive material that is easy to process and process for bipolar plates or other conductive members. Thus, there remains a need for inexpensive, highly conductive materials for bipolar fuel cell electrode plates and other conductive moldings.

[0016]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention relates to a method for producing a bipolar fuel cell electrode plate and other conductive molded articles, wherein a completely vulcanized (crosslinked) thermoplastic elastomer ( thermoplastic vulcanizat
e. A thermoplastic composition formed by adding a conductive filler to TPV) is used. Here, “fully vulcanized” refers to US Pat. No. 4,311,628.
As described in the above item, it means that it has been vulcanized (crosslinked) to an extent that it does not dissolve in cyclohexane at 23 ° C. by more than about 3%. TPV is used to exclude fillers from a discrete chemically crosslinked elastomeric phase within the TPV. By removing the filler from the elastomer phase,
Since the conductive filler remains exclusively in the continuous thermoplastic phase of the material (composition), the amount of filler required to form conductive paths in the material is reduced.

The vulcanized thermoplastic elastomer used in the present invention may be manufactured with a conductive filler or without a conductive filler. However, one feature of the present invention involves incorporating and dispersing the conductive filler into the continuous thermoplastic matrix phase of the TPV by adding the conductive filler after synthesis of the TPV. If the conductive filler is added after the formation of the TPV, the material can be made conductive with a smaller amount of filler compared to the case where the conductive filler is added before the formation of the TPV. The conductive filler increases the volume resistivity of the material by 10 ^8.
It is added in an amount sufficient to reduce it to less than Ω · cm, further to less than 10 ³ Ω · cm, preferably to less than 10 ¹ Ω · cm.

It is believed that the addition of the conductive filler after the formation of the TPV prevents the filler from entering the discrete elastomeric phase of the TPV due to the presence of a network of chemical crosslinking. Thus, a smaller amount of filler is sufficient to form the necessary conductive paths and reduce the electrical resistance of the material.

The present invention provides a conductive member formed of a thermoplastic elastomer, the thermoplastic elastomer comprising a vulcanized thermoplastic elastomer and a conductive solid filler, wherein the filler is 5%. And a volume resistivity of less than 10 ⁸ Ω · cm.

An object of the present invention is to provide a thermoplastic elastomer for a conductive member having a volume resistivity of less than 10 ⁸ Ω · cm. Another object of the present invention is to provide a conductive member which contains a thermoplastic elastomer and a conductive filler in a range of 5 to 75% by weight and is easily processed.

Still another object of the present invention is to provide a conductive molded article using a vulcanized thermoplastic elastomer, and in the vulcanized thermoplastic elastomer, a conductive path is formed. Conductive fillers have been added to the thermoplastic phase of the material to reduce the amount of filler required to reduce the electrical resistance of the material. Still another object of the present invention is to provide a thermoplastic elastomer containing a dynamically vulcanized thermoplastic resin. In this thermoplastic elastomer, a conductive path is formed to reduce the electric resistance of the material. Conductive fillers have been added to the thermoplastic phase of the material to reduce the amount of filler required. The above and other features of the present invention will become more apparent from the following description.

[0022]

DETAILED DESCRIPTION OF THE INVENTION Vulcanized thermoplastic elastomers (TPVs) are defined as (1) continuous, crystalline, semi-crystalline or amorphous polymers having a high glass transition temperature. Alternatively, it is defined as a multi-phase material having a co-continuous thermoplastic phase and (2) a discrete particulate phase. The latter discrete phase is a fully vulcanized amorphous elastomer, typically having a low glass transition temperature.

The composition of the present invention has appropriate conductivity and can be processed into a molded article or an extruded article. In a preferred embodiment of the present invention, a highly conductive material for the conductive member is used. The conductive member includes a flat planar member such as a bipolar plate, a floor material, and an annular member (an electrical connector, a wire, a cable, etc.) of a fuel cell, each of which is electrostatically generated during manufacturing and / or use. Need to be in a low state.

One of the effects obtained by reducing the amount of the filler necessary to achieve the target conductivity is that the thermoplastic processability (workability) is improved. Further, the materials of the present invention have very low volume resistivity (ie,
Even when the conductive filler is added to a level necessary to achieve a volume resistivity of less than 1 Ω · cm), the processability is maintained.

[0025] Non-limiting examples of vulcanized thermoplastic elastomers (TPV) that can be used in the present invention include the TPVs described in US Patent Nos. 4,130,535 and 4,311,628. These are blends of an olefin rubber and an olefin thermoplastic resin, in which the rubber has been completely vulcanized in a dynamic vulcanization step. The product of this dynamic vulcanization step is TPV, the latter being a two-phase material consisting of a discrete particulate phase composed of vulcanized rubber and a continuous phase composed of thermoplastic resin, Thermoplastics allow thermoplastic processing of the material.

Commercially available TPVs include thermoplastic rubber "Santoprene" (trademark of Advanced Elastomer Systems) and thermoplastic rubber "Surlink" (trademark of DMS Thermoplastic Elastomers). TPVs based on other suitable thermoplastic resin-elastomer systems can also be used to practice the present invention. Non-limiting examples thereof include rubber systems crosslinked with polyesters described in U.S. Pat.No. 4,141,863, and U.S. Pat.
There is a polyamide-EPDM system described in 915,121-A1, a polyester-acrylate rubber system described in U.S. Pat. No. 5,300,537, and a polyamide-acrylate rubber system described in U.S. Pat. No. 5,591,798.

In the present invention, the conductive filler is 1 Ω · c
means a solid filler having a volume resistivity less than m. Non-limiting examples of these include carbon in powder and fiber form (carbon black and graphite) and pitch and polyacrylonitrile (PA
There are fibers based on N). Also included are metals in the form of powders, flakes, and fibers (eg, aluminum, copper, gold, nickel, silver, steel, tungsten, zinc, etc.). Further, particles of alloys such as brass, tin, and stainless steel, and particles coated with metal (for example, glass fibers or glass spheres coated with nickel or silver) are also included. Also included are conductive polymers in the form of particles, non-limiting examples of which include conductive salts of polypyrrole, polyaniline, polythiopenes, and similar materials. Suitable fillers for the present invention are carbon black and graphite type fillers.

In the present invention, the conductive carbon black has a larger agglomerate size before the mixing step than after the mixing step. The initial agglomerate size of carbon black is not critical, but generally, almost all particles are less than 5 microns, preferably 3 microns, more preferably less than 1 micron.

The conductive carbon black added to the TPV is
Preferably, it can have a pore volume of 150 ml / 100 g or more as measured by the dibutyl phthalate (DBP) adsorption method based on ASTM D 2414-97. 400ml / 10
Carbon black having a DBP level of 0 g or around 0.05 microns is preferred. Non-limiting examples of carbon blacks suitable for the present invention include Akzo Nobel®
Chemicals “Ketjenblack EC-300J” (“Ketjenbla
"ck" is a trademark of the company) (DBP adsorption: 380), Degussa Hüll "Printex XE-2"("Printex" is a trademark of the company) (DBP adsorption: 175 ml / 100 g), Columbia Chemicals “Conductex 975U” (“Conductex”
Is the company's trademark) (DBP adsorption: 165 ml / 100g).

In the TPV, individual grades of carbon black may be used alone, or a blend of two or more types of carbon black may be added. When using carbon black in the TPV composition of the present invention, the amount thereof is 5 to 5 regardless of the type of carbon black used.
75 weight percent, preferably 20-60 weight percent. This amount can vary depending on the type of carbon black, the processing conditions used to add the carbon black, and the required level of conductivity.

The filling graphite may be synthetic or natural. Synthetic graphite is preferred because synthetic graphite has higher conductivity than natural graphite due to the layered crystal structure. Like the carbon black particles, the graphite particles have a larger particle size before the mixing step, and have a smaller particle size during the mixing step. The initial particle size of the graphite particles is not critical, but generally, almost all particles are less than 50 microns, preferably 5 microns, more preferably less than 1 micron. Since graphite has good lubricating properties, it is easy to mix graphite particles completely and homogeneously with TPV without significant loss of conductivity. As a preferred graphite, “Graphite 3120” (average particle size of 3
~ 5 microns), "Graphite A99" (average particle size 25
Micron) and "Micro 450" (average particle size 3-5 microns).

Each type of graphite may be used alone or a blend of two or more graphites may be added to the TPV. When graphite is used in the TPV composition of the present invention, regardless of the type of graphite used, the amount thereof is the same as that of carbon black, and the total amount is 5%.
７５75% by weight, preferably 20-60% by weight. This amount can vary depending on the type of graphite filler, the processing conditions used to add the graphite filler, and the required conductivity level.

Further, other types of fillers can be used in combination in the practice of the present invention. Non-limiting examples of such filler mixtures include a mixture of graphite powder and carbon powder, a mixture of graphite carbon powder and carbon fiber, a mixture of graphite fiber and carbon fiber, or a mixture of graphite carbon powder and silver powder. And mixtures of other similar materials. Any combination of conductive fillers is within the scope of the present invention. The thermoplastic processing apparatus used in the present invention comprises an extrusion,
Includes molding equipment such as injection and transfer molding.
The polar thermoplastic resin used in the present invention includes acrylic rubber, fluorine rubber, epichlorohydrin rubber, hydrogenated nitrile butadiene rubber and the like.

[0034]

The following specific examples are provided for the purpose of clarifying the features and advantages of the present invention, and are merely illustrative, and do not limit the scope of the present invention. Hardness, ultimate tensile strength (UTS) and elongation at break were each measured according to the following ASTM standard: AS
TM D 2240-97, ASTM D 412-98a, and ASTM D 412-9
8a.

Example 1 To demonstrate that a high degree of conductivity could be achieved while maintaining processability, the two graphites were each separately mixed in different proportions with an olefin-based TPV. T
PV is an olefin-based TPV with a Shore A hardness of 91 sold by Advanced Elastomer Systems, Inc. (Akron, Ohio) under the trade name "Santoprene ™ 101-87". The graphite used was a natural graphite “Graphite 3120” (particle size 3) of Asbury Carbons (Asbury, NJ).
~ 5 microns) and synthetic graphite "graphite
A99 "(average particle size 25 microns).
6. 190 ° C. in a 6 liter Banbury mixer.
Mix for 5 minutes, drop and mill, and mix in Banbury mixer for an additional 6 minutes. All samples were formed by compression molding. Table 1 shows the composition of the sample and the test results. In the table, the sample composition is% by weight. That is, sample B is 96% by weight of TPV, 4% by weight of "Graphite 3120"
It is. The volume resistivity of Samples A to F was measured using ASTM D 257-93, and that of Samples G to J was measured using ASTM D 4496-87 (reapproved 1993).

[0036]

[Table 1]

Example 2 This example shows that the addition of a conductive filler to a TPV results in a very conductive and processable material. In this example, a TPV “Santoprene” manufactured by Advanced Elastomer Systems, Inc.
(Trademark) was mixed with two different grades of graphite from Asbury Carbons and conductive carbon black from Cabot (Boston). These materials are mixed in a Moriyama mixer with a melting point higher than the melting point of TPV "Santoprene".
Mix for 30 minutes at 00 ° C. A test plate having a thickness of about 2 mm made of the material thus mixed was produced by compression molding at 200 ° C. for 4 minutes and cooling for 8 minutes. About test plates Lucas Signtone series 4
The volume resistivity was measured using a point resistance probe. The principle and operation of the series four-point resistance probe are described in LB Valdes's "Measurement of Germanium Resistance for Transistors" (Proc. Ins
t., Radio Eng., p. 42, 420-7, 1954).

[0038]

[Table 2]

Example 3 This example demonstrates a mixture of graphite, carbon black, and silver-coated glass spheres from Potters Industries, Inc. (Valley Forge, Pa.).
Fil) added to the TPV "Santoprene" shows that highly conductive materials can be obtained. Furthermore, this example shows that a large amount of oil can be added to the material to improve the melt processability. The material of this example was kneaded, and the thickness was 1.5 m in the same manner as in Example 2.
m plate. Similarly, the volume resistivity was measured using the same series four-point resistance probe as in Example 2.

[0040]

[Table 3]

FIGS. 1 and 2 show a bipolar plate (electrode plate) 10 according to a preferred embodiment of the present invention. The electrode plate 10 is a thin, flat member having a flat first surface 12 and an opposite second flat surface 16. Surface 12, 1
A channel (groove) 20 is formed in one or both of the channels 6. The electrode plate 10 has an opening 22 for supplying gas to the flow path 20 and an opening 2 for extracting exhaust gas from the flow path.
4

The unit fuel cell comprises one solid membrane electrode assembly (MEA) 28.
And one bipolar plate 10 and another similar bipolar plate 10 '. Both sides of the MEA 28 are coated with a thin platinum catalyst, hydrogen gas flows through the flow path of the anode side electrode plate of the bipolar plate pair, and air flows through the flow path of the cathode side electrode plate of the bipolar plate pair. Flows.

Accordingly, the MEA 28 is composed of a polymer electrolytic diaphragm, a catalyst layer, and a reaction electrode layer. The polymeric electrolytic diaphragm is formed of a fluoropolymer such as "Nafion" (R) or other similar materials suitable for fuel cell applications (e.g., those manufactured by WL GORE).

On the anode side, hydrogen gas dissociates into free electrons and protons in the presence of a platinum catalyst. Free electrons are bipolar plates 1
The zeros lead in the form of a current to an external circuit (not shown). Protons pass through the MEA to the cathode side, where
Oxygen from the air, electrons coming from an external circuit through an adjacent bipolar plate, and protons generate water and heat. The bipolar plate 10 'is identical to the bipolar plate 10 except that it is located on the opposite side of the MEA from the electrode plate 10.

The bipolar plates 10 and 10 'combine the TPV with the conductive filler after dynamic vulcanization of the TPV as described above to disperse the conductive filler in the continuous thermoplastic phase of the TPV. It is formed by this. This improves conductivity and reduces the volume resistivity of the material. Due to the reduced volume resistivity of the material, the fuel cell operates at a lower temperature and receives less resistance to the flow of electrons, resulting in a more effective electrochemical reaction. Further, the bipolar plate has elasticity, so that an electrode plate that is flexible, easier to assemble into a fuel cell, and hard to crack during handling is obtained. In addition, the elasticity of the bipolar plate improves the sealing property between the adjacent bipolar plates. As is apparent to those skilled in the art, in a fuel cell, it is necessary to provide an insulating layer between electrode plates in order to realize a sealing function and an electrical insulating function for the MEA.

FIG. 3 shows a floor tile according to a second embodiment of the present invention. The floor tile 200 is a thin flat member having a pair of opposing flat surfaces 210. Tile 200
Also has an edge 220. The floor tile 200 is preferably square, but any other suitable shape (rectangular, triangular,
Polygonal, circular, oval, etc.). The floor tile 200 is formed by dispersing the conductive filler in the continuous thermoplastic phase of the TPV by combining the TPV with the conductive filler after dynamically vulcanizing the TPV as described above. Molded, molded or extruded using the blended material. This improves conductivity and reduces the volume resistivity of the material. Thus, the static electricity generated by the shoes of people walking on the floor tiles in the work area is directed to the ground (not shown), and the static electricity is removed through the floor tiles in the immediate vicinity of the production area of the electro-sensitive component.

FIG. 4 shows an electric connector 300 according to a third embodiment of the present invention. The electrical connector 300 has a male connector member 310 and a female connector member 350. Male connector member 310 includes outer body portion 312 and inner body portion 3.
It has 14. Inner body portion 314 holds at least one, and preferably two or more, wires 320. Wire 320 has pins 330 protruding outwardly from outer body portion 312 of connector 300.

The female connector member 350 is connected to the outer body portion 35.
2 and an inner body portion 354. Inner body part 354
Is at least one, preferably two or more wires 360
Is held inside. Female connector member 350 has at least one, and preferably two or more, sockets 370 that interengage with wires 320 of male connector member 310. When the connector is connected, the male connector member 31
The zero pin 330 is inserted into the socket 370 and locked by a mechanical locking mechanism (not shown).

The electrical connector 300 is made of a conductive material (the TPV is dynamically vulcanized as described above, then the TPV is combined with the conductive filler, and the conductive filler is dispersed in the continuous thermoplastic phase of the TPV. Molded, molded, or extruded using the blended material. This improves conductivity and reduces the volume resistivity of the material.
Due to the reduced volume resistivity of the material, the electrical connector operates at a lower temperature and the flow of electrons undergoes less resistance. In addition, TPVs containing conductive fillers are elastic, making them flexible and easier to assemble,
It is possible to obtain a connector that is hardly damaged during handling, can reduce the possibility of accumulation of static charge in the connector 300, and can provide a sealing function.

FIG. 5 shows an electric wire or cable 400 according to a fourth embodiment of the present invention. The cable 400 has an outer skin 410 and an inner body 415. Inner body 415
Has at least one, preferably two or more wires 42
0 is buried. The outer sheath 410 and the inner body 415 of the electrical cable 400 combine the TPV with the conductive filler after dynamically vulcanizing the TPV as described above to disperse the conductive filler in the continuous thermoplastic phase of the TPV. Then, molding, molding, or extrusion molding is performed using the blended conductive material. This improves conductivity and reduces the volume resistivity of the material. Due to the reduced volume resistivity of the material, the cable operates at lower temperatures and the resistance to the flow of electrons is less. Furthermore, TPVs containing conductive fillers have elasticity, so they are flexible,
A cable is obtained that is easier to manufacture, less susceptible to breakage during handling, and that reduces the likelihood of static charge buildup on the cable 400.

As will be apparent to those skilled in the art, materials made using the principles of the present invention can be used in other conductive moldings, and they are also within the scope of the present invention. Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and the present invention includes various modifications.

[Brief description of the drawings]

FIG. 1 is a perspective view of a bipolar plate according to the present invention.

FIG. 2 is a sectional view of a fuel cell.

FIG. 3 is a perspective view of a flooring according to the present invention.

FIG. 4 is a sectional view of an electrical connector according to the present invention.

FIG. 5 is a sectional view of an electric cable according to the present invention.

[Explanation of symbols]

 10: Bipolar plate 12: Surface of electrode plate 20: Channel

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Claims (10)

[Claims] 1. A conductive thermoplastic composition comprising a vulcanized thermoplastic elastomer and a conductive solid filler, wherein the filler is in the range of 5 to 75 weight percent. A conductive thermoplastic composition having a volume resistivity of less than 10 ⁸ Ω · cm. 2. The conductive thermoplastic composition according to claim 1, having a volume resistivity of less than 10 ³ Ω · cm. Wherein a volume resistivity of 10 ⁰ Omega · conductive thermoplastic compositions based on claim 2, characterized in that less than cm. 4. The conductive thermoplastic composition according to claim 1, wherein said composition can be processed in a thermoplastic processing apparatus. 5. The conductive thermoplastic composition according to claim 1, wherein the vulcanized thermoplastic elastomer contains a polyolefin elastomer and a polyolefin thermoplastic resin. 6. The conductive thermoplastic composition according to claim 1, wherein the vulcanized thermoplastic elastomer contains an ethylene polypropylene rubber and a polypropylene thermoplastic resin. 7. The conductive thermoplastic composition according to claim 1, wherein the vulcanized thermoplastic elastomer contains a polar rubber and a polar thermoplastic resin. 8. The conductive thermoplastic composition according to claim 7, wherein the vulcanized thermoplastic elastomer contains an acrylate rubber and a polyester thermoplastic resin. 9. The conductive thermoplastic composition according to claim 7, wherein the vulcanized thermoplastic elastomer contains an acrylate rubber and a polyamide-based thermoplastic resin. 10. A bipolar plate for a fuel cell formed from the conductive thermoplastic composition according to claim 1.