WO2003025069A1 - Thermoplastic elastomer composition - Google Patents

Abstract

A thermoplastic elastomer composition having a thermoplastic elastomer material and a filler, characterized in that the filler comprises a carbon fiber having a length of 0.1 to 50 μm and a diameter of 0.002 to 0.5 μm. The carbon fiber is preferably a hollow fiber having a length of 0.1 to 30 μm and a diameter of 2 to 60 nm, i.e., the so-called carbon nanotube, or a fiber having been prepared by the vapor phase growth method and having a length of 1 to 50 μm and a diameter of 0.05 to 0.5 μm, i.e., the so-called vapor phase grown carbon fiber. The carbon fiber is preferably contained in an amount of 0.001 to 20 vol % relative to the total amount of the thermoplastic elastomer composition. The thermoplastic elastomer composition is good in thermal conductivity, electrical conductivity, thermal resistance, mechanical characteristics and the like, and also is excellent in moldability, such as kneadability.

Description

 Description Thermoplastic elastomer composition Technical field

 TECHNICAL FIELD The present invention relates to a thermoplastic elastomer composition (hereinafter, also simply referred to as “composition”). More specifically, it has good heat conductivity, electric conductivity, mechanical properties, and the like, and has molding properties such as kneading properties. The present invention relates to a thermoplastic elastomer composition having excellent heat resistance. Background art

 Various products such as electrical and electronic parts, tires, and belts have various thermoplastic elastomers based on elastic materials such as natural rubber, various thermosetting synthetic rubbers, and thermoplastic elastomers, depending on their characteristics. Tomato compositions have been used. The performance and functions of such products are greatly affected by the vulcanization conditions and other auxiliary materials, such as fillers, which are mixed in various ways, as well as the characteristics of the basic material itself as the base material.

 For example, among the elastic materials, power pump racks and silica are widely known as fillers for obtaining the reinforcing effect of natural rubber and various thermosetting synthetic rubbers, and alumina is used to enhance thermal conductivity. In order to impart electrical conductivity, for example, boron nitride or the like, and a metal powder such as copper or nickel, or conductive carbon are mixed.

 Also, there are many types of thermoplastic elastomers, from those having mechanical properties close to vulcanized rubber to those having soft physical properties like gel, and various types of materials that can exhibit a wide range of physical properties. It has been expanded to applications. Even if such a thermoplastic elastomer is to be used for an application that requires a specific function, it is possible to achieve both the required performance and the characteristics as the elastomer by adding various fillers that perform the intended function. Is achieved.

However, with the conventionally known fillers, the only way to obtain a high property-improving effect is to increase the compounding amount. As a result, it is not possible to obtain a uniform dispersion of the fillers in the volatile material. Variations in performance, increase in viscosity and decrease in physical properties However, there is a possibility that defects such as deterioration of the moldability due to the increase of the mechanical properties of the obtained elastic body composition and the practical use of the resulting elastic body composition may not be achieved.

 Therefore, an object of the present invention is to achieve various properties by using a filler that exhibits a high property improving effect only by adding a relatively small amount and does not adversely affect other performances such as mechanical properties. An object of the present invention is to provide an elastic composition having physical properties, in particular, a thermoplastic elastomer composition. Disclosure of the invention

 The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, by using a structure made of a carbon atom having a specific shape as a filler, a thermoplastic elastomer obtained by adding only a small amount is used. The inventors have found that the thermal conductivity and mechanical properties of one composition are greatly improved, and that sufficient effects can be obtained without adversely affecting the other properties, thereby completing the present invention.

 That is, the thermoplastic elastomer composition of the present invention comprises a thermoplastic elastomer material and a filler, and has at least a length of 0.1 to 50 ^ m and a diameter of 0 as the filler. It is characterized in that carbon fibers of 0.2 to 0.5 m are blended.

 The compounding amount of the carbon fiber in the present invention is preferably 0.0001 to 20% by volume of the entire thermoplastic elastomer composition. Further, the thermoplastic elastomer composition of the present invention may contain at least one of the force pump rack and the inorganic filler in an amount of 1 to 40% by volume.

 Further, the thermoplastic elastomer composition preferably has a JIS A hardness of 1 to 90.

 Further, the carbon fiber has a length of 0. ~ 30 μπι, hollow fibers with diameters of 2 to 60 nm, and fibers with a length of l to 50 iim and a diameter of 0.05 to 0.5 m produced by vapor phase growth are preferably used. be able to. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, specific embodiments of the present invention will be described. . The thermoplastic elastomer composition of the present invention comprises a thermoplastic elastomer as a base material and a carbon fiber having a specific structure as a filler. By using carbon fiber with a specific structure as the filler, it is possible to obtain sufficient effects such as thermal conductivity and mechanical properties by adding a small amount. It does not cause inconveniences such as deterioration of other properties and moldability due to the large amount of addition.

 The thermoplastic elastomer used in the present invention is a material that exhibits the properties of an elastomer at normal temperature, and is plastically deformed by an external force at a high temperature so that injection molding is possible.For example, a styrene-based material, an olefin-based material, Examples include urethane-based, ester-based, amide-based, and fluorine-based block polymers, graft polymers, ionomers, and the like, and polymers having an appropriate degree of crystallinity, such as stereoblock polypropylene and 1,2-polybutadiene. be able to. In the present invention, among the various thermoplastic elastomers, those having physical properties according to the use can be appropriately used, and there is no particular limitation.

 The carbon fiber used as the filler in the present invention preferably has a length of 0.1 to 50 mm and a diameter of 0.002 to 0.5 m, and has a hollow structure. May also be solid. As such carbon fibers, so-called carbon nanotubes and so-called vapor-grown carbon fibers produced by vapor-phase growth can be preferably used.

A carbon nanotube (CNT) is a hollow structure composed of carbon atoms with a diameter of several nm to several tens of nm, and is made of ordinary carbon fiber (CF) (average diameter 5 im ~, length 100 m). the degree) of 1 0 - ³ times of the order one, has a very fine tubular structure. Since carbon nanotubes have an aspect ratio on the order of 10 i to 10 ³ , the tensile strength is extremely high, for example, about 45 GPa, and the appearance of a repeating structure of six-membered rings constituting a cylinder have any of the electrical properties of the metal properties and semiconductor-like characteristics by people, for example, the current density is much as compared 1 O MA / cm ² in 1 G AZ cm ² degree and superconductors It is said to have excellent mechanical and electrical properties, such as high values.

The carbon nanotube to be used preferably has a length of 0.1 to 30 Hm, particularly 0.1 to 10 m.If it is shorter than 0.1 lm, the length is too small. The effect of improving the characteristics according to the invention is difficult to exert, and if it exceeds 30 m, effective dispersion in the composition is obtained because the entanglement between carbon nanotubes becomes strong. Is not easy, and neither is preferable. Further, the diameter is preferably in the range of 2 to 60 nm, particularly preferably in the range of 2.5 to 50 nm. If the diameter is smaller than 2 nm, it is difficult to obtain an effective tube structure.If the diameter exceeds 6 O nm, the aspect ratio does not increase depending on the length, and as a fibrous additive, It is not preferable because the feature becomes difficult to appear. The preferred aspect ratio of the carbon nanotube in the present invention is preferably in the range of 20 to 2000, more preferably in the range of 30 to 100.

 Preferably, carbon nanotubes are synthesized by a plasma CVD (chemical vapor deposition) method, a thermal CVD method, a surface decomposition method, a fluidized gas phase synthesis method, an arc discharge method, and the like. Those obtained by a gas phase synthesis method are particularly preferred. Either single-walled nanotubes or multi-walled nanotubes can be used, and there are no particular restrictions on the number of tubes in a single-walled tube or the number of tube-walled tubes in a multi-walled tube. In the present invention, commercially available carbon nanotubes can be used as appropriate. For example, carbon nanotubes manufactured by Materials Technologies Research, Inc. of the United States (MTR (Materials, Technologies, Research; Ltd.)) can be used. Can be used.

Further, the vapor-grown carbon fibers is usually forces one carbon fiber one (CF) (mean diameter 5 [pi! ~, Length 1 0 0 _tm about) 1 0 ² - :! of . - for ^one times the order one is a fine fibrous structure, rather difficulty arise problems such as dispersibility than the case of adding conventional carbon fiber one and achieve the same performance improvement There are advantages that can be. The vapor-grown carbon fiber is not particularly limited, and a fiber having a fiber diameter, a fiber length, and an aspect ratio according to required performance can be used as appropriate, and preferably, the average diameter is 0.0. 5 ~ 0.5 ^ m, especially in the range of 0.1 ~ 0.4 4, average length :! 550 ^ m, especially those having a range of 5〜30 m. Further, it is preferable to use one having a specific surface area of 5 to 50 m ² / g, particularly preferably 8 to 30 m ² / g. Specifically, as a commercial product, for example, vapor grown carbon fiber VGCF (registered trademark) manufactured by Showa Denko KK can be used.

The compounding amount of the carbon fiber according to the present invention is 0.1% of the entire thermoplastic elastomer composition. It is preferably within a range of from 0.1 to 20% by volume, particularly preferably from 0.1 to 15% by volume. When the content is 0.01% by volume or more, the desired performance can be sufficiently obtained, and when the content is 20% by volume or less, the expected effect of improving the performance is sufficiently exhibited. In addition, it is possible to avoid a decrease in workability in mixing and molding.

 In the thermoplastic elastomer composition of the present invention, the Young's modulus is preferably in the range of 1 to 100 MPa, particularly preferably in the range of 2 to 80 MPa. When the Young's modulus is equal to or higher than the lower limit, a decrease in physical properties such as creep property and strength can be suppressed. it can.

 The JISA hardness of the thermoplastic elastomer composition of the present invention is preferably in the range of 1 to 90.

 In the thermoplastic elastomer composition of the present invention, various reinforcing fillers (hereinafter, sometimes referred to as “other fillers”) such as carbon black, inorganic fillers, etc., in addition to the carbon fibers described above, may be used. They can be appropriately blended. The content of the other filler is preferably not more than 60% by volume, particularly preferably not more than 40% by volume of the whole filler. When a proper amount of other filler is blended in the composition, a higher reinforcing effect can be obtained as compared with a case where only carbon fiber is blended. Suitable other fillers include carbon black, silica, and inorganic fillers described below.

 Depending on the production method, carbon black includes channel black, furnace black, acetylene black, and thermal black.Specific examples include SRF, GPF, FEF, HAF, IS AF, and SAF. it can. In the present invention, any of these can be used, but it is preferable to appropriately select and use the thermoplastic elastomer composition according to the use and blending thereof.

Further, as the inorganic filler, for example, silica can be suitably used. The silica used in the present invention is not particularly limited, and those conventionally used for reinforcing rubber, for example, dry-processed silica (gayic anhydride), wet-processed silica (hydrous silicate), calcium silicate, and silicate It can be appropriately selected from aluminum and the like, and is preferably wet-process silica, which has the most remarkable effect of improving the fracture resistance. Ma In addition, colloidal characteristics and the like can be appropriately selected according to the purpose and use. For example, when wear resistance and low fuel consumption are important, those having a nitrogen adsorption specific surface area (BET) in the range of 100 m ² / g to 300 m ² Zg are suitable. Here, the BET value is a value measured in accordance with ASTM D 480-93 after drying at 300 for 1 hour.

 Other inorganic fillers include the following general formula (I),

_{^{mM 1 - XS i O y ·}} z H 2 0 (I)

(In the formula (I), M ¹ is selected from metals selected from the group consisting of aluminum, magnesium, titanium and calcium, oxides or hydroxides of these metals, and hydrates thereof. M, x, y, and z are respectively integers from 1 to 5, integers from 0 to 10, integers from 2 to 5, and integers from 0 to 10). It is preferably used. Such an inorganic filler may further contain a metal such as potassium, sodium, iron, and magnesium, an element such as fluorine, and a group such as NH ⁴ .

Specifically, alumina monohydrate _{(A 1 2 0 3 · H} 2 0), Gibusai bets, aluminum hydroxide, etc. Baiyarai preparative _{[A 1 (OH) 3]} , magnesium hydroxide [Mg (OH), magnesium oxide (MgO), talc (3 Mg_〇 _{'4 S i 0 2' H} 2 〇), § evening Parujai bets (5 Mg O '8 S i 〇 _2' 9 H ₂ 0), titanium white (T i 〇 _2), titanium down black (T i 0 _2n - J, calcium oxide (C a O), calcium hydroxide _{[C a (OH) 2]} , magnesium aluminum oxide (MgO 'A l ₂ 〇 _3), clay (A _{l 2 O - 2 S i 0} 2), kaolin _{(Α 1 2 0 3 · 2} S i Ο 2 · 2 H 2 0), Pairofui La wells _{(A l 2 0 3 '4} S i 0 2' H ₂ 0), bentonite bets (A l ₂ 〇 _{3 '4 S i 0 2'} 2 H 2 〇), Kei aluminum (A 1 ₂ S i 〇 _{5, A 1 4 · 3 S} i O 4 · 5 H 2 0), magnesium silicate (Mg ₂ S i〇 ₄ , Mg S i〇 ₃ etc.), calcium silicate (C a ₂ ′) S i 0 _4, etc.), Kei calcium aluminum (A l ₂ 〇 ₃ 'C aO' 2 S i 〇 _2, etc.), Keisan magnesium calcium (C AMG S I_〇 _4), various Zeorai DOO, long stone, Mai And M1 are preferably montmorillonite, etc. In particular, M ¹ is preferably aluminum, and particularly preferably aluminas and clays. Among the inorganic fillers represented, the following general formula (I 1),

A 1 ₂ 〇 _{3 · n H 2 O (II} )

(In the formula (II), n is an integer of 0 to 3.)

It means what is represented by.

The clays, clay _{(Α 1 2 0 3 · 2} S i 0 2), kaolin (Α 1 ₂ 〇 ₃ -

2 S i 0 ₂ · 2 H ₂ 0), pyrophyllite (A l ₂ 0 ₃ '4 S i 0 ₂ ' H ₂ 〇), bentonite (A l ₂ 〇 ₃ '4 S i 0 ₂ ' 2) H ₂ 0), Ru include Monmori furnace bets like.

 In the present invention, these other fillers may be used alone or in combination of two or more.

 In the thermoplastic elastomer composition of the present invention, in the case where a silicic acid or other inorganic filler is used, a coupling agent can be blended as required to further improve its effect. The coupling agent is not particularly limited, and any one of various conventionally known coupling agents can be selected and used. Among them, a silane-based coupling agent is particularly preferable.

Here, examples of the silane coupling agent include the general formula (RO) ₃ S i -S m-S i (OR) ₃ or XS i (OR) ₃ (where R is X is a functional group that reacts with an organic substance (eg, a mercaptoalkyl group, an aminoalkyl group, a vinyl group, an epoxy group, a glycidoxyalkyl group, a benzothiazolyl group). , N, N-dimethylcarbamoyl group, etc.), and m is an integer satisfying 0 <m≤9), specifically, bis (3-triethoxysilylpropyl). ) Tetrasulfide, bis (3-trimethoxysilylpropyl) tetrasulfide, bis (3-methyldimethoxysilylpropyl) tetrasulfide, bis (3-triethoxysilylethyl) tetrasulfide, Bis (3-triethoxysilylpropyl) disulphide, bis (3-trimethoxysilylpropyl) disulphide, bis (3-triethoxysilylpropyl) trisulphide, 3-mercaptopropyl trimethoxysilane, 3-mercaptopropyl Triethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3 3-aminopropyl trimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, r-glycidoxypropyltrimethyoxysilane, α-glycidoxypropyl mouth-methylpytoxysilane, 3-trimethoxysilylpropyl-N, N-dimethylcarbamoyltetra Sulfide, 3-trimethoxysilylpropylbenzothiazolyltetrasulfide, 3-trimethoxysilylpropylmethacryloyl monosulfide and the like.

 In the present invention, such a coupling agent may be used alone, or two or more kinds may be used in combination. It is preferable that the compounding amount is selected in the range of 1% by weight to 50% by weight based on the total amount of the silica and the other inorganic filler. If the amount is less than 1 part by weight, the effect of the compounding may not be sufficiently exhibited. If the amount is more than 50% by weight, the effect is not improved in proportion to the amount, which is rather disadvantageous economically. In consideration of the mixing effect and the economical efficiency, the more preferable content of the coupling agent is in the range of 2% by weight to 40% by weight, particularly preferably 5% by weight to 30% by weight.

 The thermoplastic elastomer composition of the present invention has a low thermal conductivity by blending a small amount of the above-mentioned predetermined carbon fiber without significantly changing other physical properties and without impairing moldability. It can be widely used in electrical and electronic parts, tires, belts, and various other products because it can significantly improve properties such as electrical conductivity. In addition, the thermoplastic elastomer composition of the present invention includes, in addition to the reinforcing filler described above, for example, an antioxidant, a lubricant, a surface treatment agent, a pigment, an ultraviolet absorber, an antistatic agent, a dispersant, A neutralizing agent, a foaming agent, a cross-linking agent, and the like can be appropriately used. As a method for mixing and molding the thermoplastic elastomer composition of the present invention, a known method used for mixing and molding of various ordinary compositions can be used, and there is no particular limitation.

 Hereinafter, the present invention will be described in more detail with reference to Examples.

 1. Example of using carbon nanotube as carbon fiber

 (Example 1 and Comparative Examples 1 to 3)

In the composition shown in Table 1 below, styrene ethylene propylene styrene block copolymer (SEPS) as a thermoplastic elastomer and polypropylene (P P) and various additives were mixed and kneaded with a roll at 150 ° C., and then a sheet of a thermoplastic elastomer composition having a thickness of 0.5 mm was produced by an electric heat press. The amounts in Table 1 below all indicate parts by weight.

Table 1

 1) Kuraray Co., Ltd. Trademark: Septon 4 0 7 7

 2) Exxon Chemical Co., Ltd., Trademark: Achieve

 3) Idemitsu Kosan Co., Ltd., Trademark: Diana Process Oil PW380

 4) Multilayer carbon nanotube (closed), tube diameter: 7 to 12 nm, tube length: 0.5 to 10 urn, tube layer: 5 to 50 layers, manufactured by MTR (Materials Technologies Research), U.S.A., ARC Made by the discharge method

 5) Showa Denko K.K., Trademark: AS-10 (particle size 36 iim)

Evaluation of the physical properties

 The sheets of each of the obtained compositions were evaluated for their JISA hardness, fracture physical properties (rupture strength, elongation at break) and thermal properties (thermal conductivity, thermal resistance). The JISA hardness is measured in accordance with JISK 6253-19997, the breaking strength and the elongation at break are measured in accordance with JISK625-1—1997, and the thermal conductivity is measured in Kyoto. The thermal resistance was measured using a rapid thermal conductivity meter QTM-500 manufactured by Electronics (II), and the thermal resistance was measured using a transistor radiator-type thermal resistance meter manufactured by Com Electronics Co., Ltd. The results are shown in Table 2 below.

Table 2 Comparative Example 1 Example 1 Comparative Example 2 Comparative Example 3

 Hardness (JIS A) 80 80 81 85

 Breaking strength (MPa) 5.8 5.8 5.8 3.8

 Elongation at break (%) 98 90 90 60

 Thermal conductivity (W / m -K) 1.2 1.6 1.2 1.5

 Thermal resistance (° czw) 1.4 1.1 1.4 1.4

 As is evident from the results in Table 2 above, the thermoplastic elastomer composition of Example 1 containing about 1.1% by volume of carbon nanotubes had a good thermal conductivity. Compared to Comparative Example 1, which uses only alumina, the thermal conductivity is significantly improved.This is due to the comparison of Comparative Example 2 in which alumina was increased instead of carbon nanotubes. The difference between the two can be clearly seen. Furthermore, when compared with Comparative Example 3 in which the amount of alumina was greatly increased, the physical properties of the composition were reduced when a large amount of alumina was added, so that an effect of improving thermal conductivity equivalent to that of the carbon fiber used in the present invention was obtained. It turns out to be difficult. That is, the addition of carbon nanotubes improves the values of thermal conductivity and thermal resistance without adversely affecting the hardness and the crushing properties. It was confirmed that a performance improvement effect equal to or higher than that obtained by simply adding was obtained.

 (Example 2 and Comparative Examples 4, 5)

 Next, a similar experiment was performed using a system in which the thermoplastic elastomer was changed to a styrene-butadiene-styrene triblock copolymer.

 In the composition shown in Table 3 below, styrene-butadiene-styrene triblock copolymer (SBS) as a thermoplastic elastomer and various additives were mixed and rolled into a 150 roll. After kneading, a sheet of a thermoplastic elastomer composition having a thickness of 0.5 mm was produced by an electric heat press. The amounts in Table 3 below all represent parts by weight.

Table 3 Comparative Example 4 Example 2 Comparative Example 5

SBS ⁶⁾ 100 100 100

Carbon nanotube ⁴⁾ 0 10 0

Alumina ⁵ ) 0 0 10 4) MTR (Materials Technology Research) U.S.A., multi-layer carbon nanotube (closed), tube diameter 7 to 12 nm, tube length 0.5 to 10 m, tube layer 5 to 50, AR Made by C discharge method

5) Showa Denko Co., Ltd., Trademark: AS-10 (particle size 36 m)

6) Made by Asahi Kasei Corporation, Trademark: Asaprene T-1 420

 Physical properties of the obtained sheets of the respective compositions were evaluated in the same manner as described above. The results are shown in Table 4 below.

Table 4

 As is evident from the results in Table 4 above, similar effects can be obtained even when the rubber type and filler are changed.

 2. Example of using vapor grown carbon fiber as carbon fiber

 (Example 3 and Comparative Examples 6 to 8)

 The blending contents shown in Table 5 below were used to mix styrene ethylene propylene styrene block copolymer (SEPS) as a thermoplastic elastomer, polypropylene (PP), and various additives. After kneading with a roll at ° C, a sheet of a thermoplastic elastomer composition having a thickness of 0.5 mm was produced by an electric heat press. The amounts in Table 5 below are all parts by weight.

Table 5

) Kuraray Co., Ltd. Trademark: Septon 4 0 7 7 2) Exxon Chemical Co., Ltd., Trademark: Achieve

 3) Idemitsu Kosan Co., Ltd., Trademark: Diana Process Oil PW380

 5) Showa Denko Co., Ltd., Trademark: AS-10 (particle size 36 m)

 7) Vapor-grown carbon fiber (VGCF F ™) manufactured by Showa Denko KK (fiber diameter 0.15 im, fiber length 10 to 20 μm)

 Physical properties of the obtained sheet of the thermoplastic elastomer composition were evaluated in the same manner as described above. The results are shown in Table 6 below.

Table 6

 As is clear from the results in Table 6 above, in the thermoplastic elastomer composition of Example 3 containing about 1.1% by volume of the vapor-grown carbon fiber, Comparative Example 6 using only alumina, Good thermal resistance was obtained in comparison with Comparative Example 7 in which alumina was increased in place of the vapor grown carbon fiber, and Comparative Example 8 in which alumina was significantly increased. The same performance improvement effect has been obtained with the addition of a small amount of about one-tenth of alumina. That is, it was confirmed that the addition of the vapor-grown carbon fiber improved the thermal conductivity and the thermal resistance without adversely affecting the hardness and the crushing property.

 (Example 4, Comparative Examples 9, 10)

 Next, a similar experiment was conducted using a system in which the thermoplastic elastomer was changed to a styrene-butadiene-styrene triblock copolymer.

The styrene-butadiene-styrene triblock copolymer (SBS) as a thermoplastic elastomer was mixed with various additives in the composition shown in Table 7 below to form a roll at 150 ° C. After kneading, a sheet of a thermoplastic elastomer composition having a thickness of 0.5 mm was produced by an electric heat press. The amounts in Table 7 below all represent parts by weight. Table 7

 5) Showa Denko Co., Ltd., Trademark: AS-10 (particle size: 36 im)

 6) Made by Asahi Kasei Corporation, Trademark: Asaprene T—420

 7) Vapor-grown carbon fiber (VGCF (trademark)) (fiber diameter 0.15, manufactured by Showa Denko KK) Sheets of each composition obtained were evaluated for physical properties in the same manner as described above. The results are shown in Table 8 below.

Chapter 8

 As is clear from the results in Table 8 above, it can be seen that the same effect can be obtained even if the rubber type and filler are changed. Industrial applicability

 As described above, according to the thermoplastic elastomer composition of the present invention, by using a structure composed of a carbon atom having a specific shape as a filler, the hardness and the fracture can be improved even when a small amount is added. Significant improvements in properties such as thermal conductivity, thermal resistance, and electrical conductivity can be obtained without significantly changing other physical properties such as physical properties and without impairing moldability. Therefore, the thermoplastic elastomer composition of the present invention can be used not only widely in electric and electronic parts, tires, belts, and other various products, but also with little increase in hardness, while maintaining flexibility. Since a low thermal resistance value can be obtained, it is extremely effective when used for heat dissipation sheets.

Claims

The scope of the claims 1. It contains a thermoplastic elastomer and a filler, and the filler contains at least a carbon fiber with a length of from 0:! To 50 im and a diameter of from 0.02 to 0.5 m. What is claimed is: 1. A thermoplastic elastomer composition, comprising:  2. The thermoplastic elastomer composition according to claim 1, wherein the compounding amount of the carbon fiber is 0.001 to 20% by volume of the entire thermoplastic elastomer composition.  3. The thermoplastic elastomer according to claim 1, further comprising at least one kind of a force pump rack and an inorganic filler as the filler, in an amount of 1 to 40% by volume of the entire thermoplastic elastomer. Composition.  4. The thermoplastic elastomer composition according to claim 1, wherein the JISA hardness is 1 to 90.  5. The thermoplastic elastomer composition according to claim 1, wherein the carbon fiber is a hollow fiber having a length of 0.1 to 30 μιη and a diameter of 2 to 60 nm.  6. The thermoplastic elastomer composition according to claim 1, wherein the carbon fiber is a fiber having a length of l to 50 im and a diameter of 0.05 to 0.5, produced by a vapor growth method.