JP2008266586A - Low electric conductivity high heat radiation polymer material and molded article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polymer material and a molded article that can assure both characters of low electrical conductivity and high heat radiation property. <P>SOLUTION: The low electric conductivity and high heat radiation polymer material is produced by combining a polymer material 1 with a carbon fiber 2 of 10-35 vol% and a ceramics 3 of 1-20 vol%, and the molded article is made from the low electric conductivity and high heat radiation polymer material, wherein, the ceramics is e.g. alumina (Al<SB>2</SB>O<SB>3</SB>), aluminium nitride (AlN), boron nitride (BN), silicone nitride (Si<SB>3</SB>N<SB>4</SB>), and silicon carbide (SiC), etc. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a polymer material having a low electrical conductivity and a high heat dissipation property and a molded body.

In terms of the environment such as CO ₂ reduction, the fuel efficiency of automobiles has been reduced. In recent years, hybrid cars have attracted attention. In the future, the spread of fuel cell vehicles and the like is also expected. Among them, there are many products that require low electrical conductivity and high heat dissipation in battery and motor-related parts, and various materials and shapes have been studied in order to ensure both characteristics.

However, it is difficult to ensure both characteristics with a single practical material. This is because high heat dissipation is premised on high thermal conductivity (high thermal conductivity), but practical materials having high thermal conductivity are almost always high in electrical conductivity. That is,
(1) A metal has high thermal conductivity and high heat dissipation, but also has high electrical conductivity, so low electrical conductivity (preferably electrical insulation) cannot be secured as it is. Therefore, it is necessary to separately set an insulating plate made of resin or the like, and the low heat dissipation of the insulating plate becomes a problem, or the product weight increases by the amount of the insulating plate. Also, the metal itself has a high specific gravity.
(2) Although the polymer material (resin, rubber) has low electrical conductivity (substantially electrical insulation), it is also low thermal conductivity, so high heat dissipation cannot be secured as it is. Therefore, it is necessary to secure high heat dissipation by devising the product shape (creating air passages), and the product becomes large and requires a large installation space.

(3) Therefore, the following composite materials are being studied.
Patent Document 1 describes a polymer material in which a graphitized hydrocarbon containing a boron compound is blended.
Patent Document 2 describes a material in which graphitized carbon fiber and an electrically insulating heat conductive filler are blended in silicone rubber.
Patent Document 3 describes a material in which heat conductive filler particles whose surface is coated with a ceramic material are blended in a polymer material.
Patent Document 4 describes a material in which an organic compound having a hydroxyl group and a metal oxide are blended in a polymer such as rubber.
Patent Document 5 describes a material in which boron nitride is blended in silicone rubber.
Patent Document 6 describes a material in which boron nitride whose surface is coated with amino-modified silicone oil is blended in silicone rubber.
Patent Document 7 describes a material in which liquid nitride or the like is mixed with aluminum nitride powder or metal powder.
JP 2002-88249 A Japanese Patent Laid-Open No. 2002-3717 Japanese Patent Laid-Open No. 9-32191 JP-A-7-145270 JP-A-7-111300 JP 7-33983 A JP 2004-10880 A

Patent Documents 1 to 7 are composites of the idea of ensuring both characteristics by filling a polymer material (base material) that provides low electrical conductivity with a filler made of ceramics or the like that provides high heat dissipation. Material. However, this composite material also has the following problems.
(A) High heat dissipation cannot be ensured unless the filler is filled in a considerably large amount (in high density).
(B) Since a large amount of filler is filled, the product shape is limited (limited to a sheet shape).
(C) The coating may be broken during mixing, and the conductive portion of the filler may be exposed, resulting in lack of reliability.

  An object of the present invention is to provide a polymer material and a molded body that can solve the above-described problems and can ensure both low electrical conductivity and high heat dissipation characteristics.

[A] The low electrical conductivity and high heat dissipation polymer material of the present invention comprises 10 to 35% by volume of carbon fiber and 1 to 20% by volume of ceramic in the polymer material. did.

The aspect of each element in the present invention is exemplified below.
[1] Polymer material Although it does not specifically limit as a polymer material, Resin, rubber | gum, a thermoplastic elastomer can be illustrated, It is PE (polyethylene), PP (polypropylene), PPS (polyphenylene sulfide), an epoxy resin, or silicone. It is preferable.
1. Resins: Olefin resins such as PP and PE, styrene resins such as PS (polystyrene), vinyl resins such as PVC (polyvinyl chloride), PPS, LCP (liquid crystal polymer), PBT (polybutylene terephthalate), PET (polyethylene) Examples thereof include thermosetting resins such as terephthalate), PA (polyamide) such as PA6 (polyamide 6), engineering plastic resins such as PTFE (polytetrafluoroethylene) and POM (polyacetal), epoxy resins, phenol resins, and acrylic resins.
2. Rubber: EPDM (ethylene propylene diene copolymer), CR (chloroprene rubber), NBR (acrylonitrile-butadiene rubber), silicone rubber and the like can be exemplified.
3. Thermoplastic elastomers: Examples of olefin-based, styrene-based, vinyl chloride-based, polyester-based, polyurethane-based, polyamide-based, and fluorine-based thermoplastic elastomers.

  The polymer material is not particularly limited, but preferably has a thermal conductivity of less than 1.0 W / m · K. The thermal conductivity is more preferably 0.1 to 0.5 W / m · K. Specifically, those shown in the following Table 1 can be exemplified. Table 2 shows the thermal conductivity of the carbon fibers and ceramics.

  Regarding the relationship between the thermal conductivity of a resin or the like filled (blended) with a ceramic or the like, and the thermal conductivity and filling rate of the ceramic or the like, there is a Bruggeman formula shown in the following formula 1. Since the thermal conductivity of the resin (shown in Table 1) is smaller than the thermal conductivity of the ceramics and carbon fibers (shown in Table 2), the resin etc. was filled with the ceramic etc. by changing the resin etc. The effect on the thermal conductivity (change in thermal conductivity) is small.

φ: Volume filling rate of ceramics, etc. λe: Thermal conductivity of resin filled with ceramics, etc. λd: Thermal conductivity of ceramics, etc. λc: Thermal conductivity of resin, etc.

[2] Carbon fiber Although it does not specifically limit as carbon fiber, A PAN-type carbon fiber and a pitch-type carbon fiber can be illustrated, and it is preferable that it is a pitch-type carbon fiber.

[2-1] PAN-based carbon fiber Generally, a PAN-based carbon fiber is a carbon fiber using PAN (polyacrylonitrile) fiber as a raw material, and the PAN fiber is calcined at 1000 ° C. to 1500 ° C. in an inert gas, Thereafter, it is carbonized at 2000 to 3000 ° C. for production.
A characteristic of PAN-based carbon fibers is that the graphite crystals constituting the carbon fibers are small and randomly arranged, so that electricity and heat can be easily passed in various directions of the fibers. In addition, since PAN-based carbon fibers have many defects in crystals, their thermal conductivity is smaller than that of pitch-based carbon fibers.

[2-2] Pitch-based carbon fiber In general, pitch-based carbon fiber is carbon fiber made from petroleum-based tar. The tar is blended with various compounding agents such as a thickener, and yarn is formed at 250 to 400 ° C. And then carbonized at 1000 to 1500 ° C. in an inert gas and further baked at 2500 to 3000 ° C.
Graphite crystals in pitch-based carbon fibers are larger than PAN-based carbon fibers, neatly arranged in the fiber length direction, and have few defects. Therefore, the pitch-based carbon fiber can easily conduct electricity and heat in the fiber length direction, and its thermal conductivity is much higher than that of the PAN-based carbon fiber. The reason why the thermal conductivity of the pitch-based carbon fiber is greatly increased by the orientation described later is that the direction of thermal conduction is aligned by aligning the fiber length direction.

[3] Ceramics The ceramics is not particularly limited, and examples thereof include metal oxides, nitrides and carbides, and boron nitride, alumina or aluminum nitride is preferable. In addition, the shape of the ceramic is not particularly limited, but examples thereof include powdery, fibrous, and scale-like shapes, and the dimensions are not particularly limited, but an average particle diameter of 5 to 100 μm can be exemplified.
[3-1] Oxide The metal oxide is not particularly limited, and examples include alumina (Al ₂ O ₃ ), zirconia (ZrO ₂ ), and magnesia (MgO).
The [3-2] nitride metal nitride is not particularly limited, aluminum nitride (AlN), boron nitride (BN), silicon nitride _(Si 3 _{N 4)} or the like can be exemplified.
[3-3] Carbide The metal carbide is not particularly limited, and examples thereof include silicon carbide (SiC) and boron carbide (B ₄ C).

[4] Compounding amount [4-1] Carbon fiber compounding amount The carbon fiber compounding amount in the polymer material is 10 to 35% by volume, preferably 15 to 30% by volume, and 15 to 25%. More preferably, it is volume%. When the blending amount is small, sufficient heat dissipation tends not to be secured, and when the blending amount is large, low electrical conductivity tends to be impaired or processability tends to deteriorate.
[4-2] Blending amount of ceramics The blending amount of the ceramics in the polymer material is 1 to 20% by volume, and more preferably 5 to 15% by volume.

[5] Orientation of carbon fiber The carbon fiber blended in the polymer material can be oriented by a magnetic field or the like. With this orientation, there is a merit that the thermal conductivity can be increased even if the blending amount of the carbon fiber is the same, or that the blending amount of the carbon fiber can be reduced if the same thermal conductivity is acceptable. The orientation is a state in which carbon fibers are regularly arranged in a specific direction in a polymer material as a base material.

[5-1] Confirmation or Evaluation of Orientation Orientation can be confirmed, for example, by the following two methods, and particularly by Method 1.
1. Measurement of azimuth intensity distribution of crystal lattice of carbon fiber by X-ray diffraction For example, in carbon fiber, graphite crystals are regularly arranged in the fiber length direction, and X-ray diffraction is performed on the graphite crystal (0.0.2) plane. By measuring the azimuth intensity distribution by (for example, FIG. 5 described later), the orientation direction of the carbon fiber itself can be known. In the case of orientation, a peak occurs in the azimuth intensity distribution. In the case of particularly good orientation, the half width is measured for the peak, and the following degree of orientation is defined. It can be said that the degree of orientation is such that the orientation can be visually perceived when 0.7 or more and the action effect of the orientation becomes clear.
Degree of orientation = (180 ° −half-value width) / 180 ° Formula 2
2. Visual confirmation by microscopic observation etc. A molded object is cut in the surface which wants to confirm orientation, and the direction of carbon fiber is observed with a scanning electron microscope. However, from this observation, it is difficult to quantitatively say the degree of orientation.

[5-2] Orientation direction The direction in which the carbon fibers in the polymer material are oriented is not particularly limited. For example, when the molded body includes a plate-shaped portion, any of the carbon fibers along the surface of the plate-shaped portion is used. One direction may be sufficient and the thickness direction of the plate-shaped part may be sufficient.

[5-3] Orientation Method The method for orienting the carbon fiber is not particularly limited, and examples thereof include the following magnetic field method and processing method.
1. Method by magnetic field Molding a molded body or a molded body as a raw material of the molded body with the above-mentioned low electrical conductivity and high heat dissipation polymer material, and the polymer material of the molded body having fluidity In this method, the carbon fibers in the material are oriented by a magnetic field. The carbon fibers are oriented along the direction of the magnetic field (the direction of the magnetic field lines). After the orientation, the polymer material is solidified by cooling or the like. The strength of the magnetic field is not particularly limited, but a strong magnetic field of 1T (Tesla) or more is preferable. According to this method, there is an advantage that various alignment directions including the alignment direction exemplified above can be realized only by aligning the alignment direction with the direction of the magnetic field.
Here, the state in which the polymer material has fluidity is not particularly limited, but examples include a melted state and a state before crosslinking and polymerization.
2. Method by processing A molded body or a molded body as a raw material of the molded body is molded with the above-mentioned low electrical conductivity high heat dissipation polymer material, and the molded body is in a state where the polymer material of the molded body has fluidity. In this method, at least a part is stretched and deformed by processing to orient the carbon fibers in the polymer material. The carbon fibers are oriented along the extension direction. After the orientation, the polymer material is solidified by cooling or the like.
In the above method, the molded body as the material of the molded body refers to, for example, a sheet material in a case where the molded body is a sheet material formed into a three-dimensional shape by vacuum forming or the like of the sheet material. It refers to a precursor molded body when it undergoes molding.

[B] The low electrical conductivity high heat dissipation molded article of the present invention is formed from the above low electrical conductivity high heat dissipation polymer material.
Although it does not specifically limit as a specific product of the molded object, The following product can be illustrated.
As shown in FIG. 2, an insulating plate 12, a battery case 13, a bus bar module, etc. that insulates the battery elements of the battery pack 11 (such as an electric drive vehicle such as a hybrid vehicle or a fuel cell vehicle) Motor coil insulators, sealing materials, etc. for motors, inverter cases (for electric drive vehicles, home appliances, etc.), heat dissipation sheets (for home appliances, personal computers, etc.), housings, etc.

The development history and operation of the present invention are as follows.
Carbon fiber is suitable for this purpose because it has a high thermal conductivity (and hence a high heat dissipation property) and also has a reinforcing property to the polymer material. However, since carbon fiber has high electrical conductivity, the present invention aims to suppress the electrical conductivity of the material blended with carbon fiber.
As a result of various studies, a new material having low electrical conductivity and high heat dissipation was obtained by combining carbon fiber and various insulating ceramics in a polymer material. .

  According to the polymer material and the molded body of the present invention, both low electrical conductivity and high heat dissipation characteristics can be ensured.

  It is a low-electric-conductivity, high-heat-dissipating polymer material obtained by blending 15 to 30% by volume of carbon fiber and 5 to 15% by volume of ceramic in the polymer material. Moreover, it is the low electrical conductivity high heat dissipation molded object shape | molded with the same low electrical conductivity high heat dissipation polymer material.

  Table 3 below uses polyethylene (PE) resin (trade name “Sumikasen G807” manufactured by Sumitomo Chemical Co., Ltd.) as the polymer material 1 of the base material, and carbon fiber 2 and ceramics 3 are placed on this polyethylene resin. It is a composition and physical property of Examples 1-15 which mix | blended fixed quantity, and Comparative Examples 1-5 which mix | blended predetermined amounts of carbon fiber.

Examples 1 to 11 are blends of carbon fibers and boron nitride, Examples 12 to 14 are blends of carbon fibers and alumina, and Example 15 is blends of carbon fibers and aluminum nitride. It is a thing.
On the other hand, Comparative Example 1 is a polyethylene resin only, Comparative Examples 2 and 3 are those containing only carbon fibers, and Comparative Examples 4 and 5 are those containing only boron nitride.

  In addition, Table 4 below shows, as a polymer material 1 as a base material, polypropylene (PP) resin (trade name “Novatech PP” manufactured by Nippon Polypro) instead of polyethylene (PE) resin, polyphenylene sulfide (PPS). Resin (trade name “Torelina A900” manufactured by Toray Industries, Inc.), silicone rubber (trade name “KE106” manufactured by Shin-Etsu Chemical Co., Ltd.) or bisphenol A type epoxy resin (trade name “Epomount” manufactured by Refine Tech) The compositions and physical properties of Examples 16 to 43 and Comparative Examples 6 to 8 using

The polymer materials of the base materials used for each sample are polypropylene resin in Examples 16 to 24 and Comparative Example 6, PPS resin in Examples 25 to 33 and Comparative Example 7, and silicone in Examples 34 to 42 and Comparative Example 8 Rubber, Example 43, is a bisphenol A type epoxy resin.
Moreover, Examples 16-19, 25-28, 34-37 mix | blend carbon fiber and boron nitride, and Examples 20-23, 29-32, 38-41, and 43 are carbon fiber. Examples in which alumina was blended, Examples 24, 33, and 42 were blended with carbon fiber and aluminum nitride.

The carbon fiber used in this test is a product name “DIALEAD K223HGM” (average particle diameter Φ10 × 50 μm) manufactured by Mitsubishi Chemical Corporation, which is a pitch-based carbon fiber, and boron nitride (BN) is , Trade name “PT110” (average particle size 50 μm) manufactured by GE Specialty Materials, and alumina (Al ₂ O ₃ ) are trade names “DAW10” (average particle size 10 μm) manufactured by Denki Kagaku Kogyo Co., Ltd. Aluminum nitride (AlN) is a trade name “FAN-f80” (average particle size 80 μm) manufactured by Toyo Aluminum.

[Molding and physical properties test]
The ingredients of each example or comparative example were mixed at a temperature of 210 ° C. (polyethylene resin), 200 ° C. (polypropylene resin), 320 ° C. (PPS) using a laboratory mixer (model number “KF70V”) manufactured by Toyo Seiki Seisakusho. Resin), room temperature (silicone rubber, bisphenol A type epoxy resin), rotation speed 100 rpm, time 10 minutes, and filling rate 70%. After mixing, the material was mixed with a hand press at a pressure of 20 MPa, polyethylene resin at 210 ° C. for 5 minutes, polypropylene resin at 200 ° C. for 5 minutes, PPS resin at 320 ° C. for 5 minutes, and silicone rubber at 150 ° C. for 30 minutes. The bisphenol A type epoxy resin was press-molded at room temperature for 24 hours to prepare a test piece of 25 mm × 25 mm × (thickness) 2 mm.

About each test piece, the physical property was measured with the following method.
(1) Thermal conductivity measurement The product name “Xe flash analyzer LFA447 Nanoflash” manufactured by NETZSCH was used as a measuring device, and the measurement was performed at 25 ° C. (room temperature). The direction of heat conduction is the thickness direction of the test piece.
(2) Volume Specific Resistance Measurement When the volume specific resistance was 10 ⁶ Ω · cm or less, a product name “Loresta GP” manufactured by Dia Instruments Co., Ltd. was used as a measuring device, and measurement was performed by a four-terminal method. Both the separation direction (current direction) of the current application terminal and the separation direction (potential difference direction) of the voltage measurement terminal are the thickness direction of the test piece.
When the volume resistivity was 10 ⁶ Ω · cm or more, the product name “Hiresta UP” manufactured by Dia Instruments Co., Ltd. was used as the measuring device, and the measurement was performed by the double ring method (JISK6911 compliant).

[Evaluation of the physical properties]
All of the Examples ensure both low electrical conductivity (volume resistivity 1 × 10 ² Ω · cm or more) and high heat dissipation (thermal conductivity 0.5 W / m · K or more). On the other hand, although the low electrical conductivity is ensured about the comparative examples 1 and 6-8, high heat dissipation is bad. In Comparative Examples 2 and 3, high heat dissipation is ensured, but low electrical conductivity is extremely poor. In Comparative Examples 4 and 5, both low electrical conductivity and high heat dissipation are ensured, but the mechanical strength is small, so it is not practical.
In addition, when evaluating the thermal conductivity and electrical conductivity of each compounding material, the required high heat dissipation is required depending on the specific product type of the low electrical conductivity, high heat dissipation molded product molded from the compounding material. It should be taken into account that the level of low and the level of low electrical conductivity are different.

[Preliminary test for orienting carbon fibers]
First, a preliminary test was performed to confirm that the carbon fibers can be oriented by a magnetic field. Polyethylene resin blended with 15% by volume, 25% by volume, 30% by volume, or 35% by volume of pitch-based carbon fiber, and 15% by volume of pitch-based carbon fiber and 5% by volume of alumina with an average particle size of 10 μm. 5 types of materials are mixed under the same conditions as above and formed into a test piece of 25 mm × 25 mm × 2 mm, and then carbon fiber is 15 volume%, 25 volume%, 35 volume% and carbon fiber and alumina. The magnetic field was applied to the examples of blending (the magnetic fiber was not applied to the example of 30% by volume of carbon fiber, and the magnetic field was applied to the example of 25% by volume of carbon fiber). Specifically, as shown in FIGS. 3 and 4, the orientation was performed by the following apparatus and procedure.
-A cooling superconducting magnet device (HF10-100VHT) manufactured by Sumitomo Heavy Industries, Ltd. was used as the magnetic field generating means.
An electric heater 23 is installed in the lower part of the space 22 (bore) located in the center of the magnetic field of the apparatus 21, and the test piece 24 is placed on the electric heater 23 one by one in the thickness direction of the test piece. It was set so as to be in the direction of the magnetic field (direction of the lines of magnetic force).
The test piece 24 in the same space was heated with an electric heater 23 to a temperature range where the polyethylene resin was melted (the temperature was 220 ° C.), and the base material polyethylene resin of the test piece was melted. At this time, the test piece was held so as to maintain the above dimensions.
While maintaining the same heating and temperature, the apparatus was operated to apply a magnetic field to the test piece (implemented 8T (Tesla)), and the test piece 24 was left in the magnetic field for 1 hour.
Thereafter, the heating was stopped, and the test piece 24 was allowed to stand for 0.5 hours to be naturally cooled, thereby solidifying the base material polyethylene resin of the test piece.
-The test piece 24 was taken out from the space 22 of the apparatus 21, and the orientation of the carbon fiber was confirmed.

The orientation of the carbon fiber was confirmed by the following two methods.
1. Measurement of azimuth intensity distribution of crystal lattice of carbon fiber by X-ray diffraction Example of blending 30% by volume of carbon fiber not applying a magnetic field, Example of blending 15% by volume of carbon fiber to which a magnetic field is applied, Example of blending 35% by volume And as for the example of blending carbon fiber and alumina, using an X-ray diffractometer, as described above, the azimuth intensity distribution by X-ray diffraction was measured for the graphite crystal (0.0.2) plane of the carbon fiber. The measurement results are shown in FIG. The carbon fiber is well oriented in the thickness direction of the test piece 24 in the example of blending 15% by volume of carbon fiber to which a magnetic field is applied, in the example of blending 35% by volume, and in the example of blending carbon fiber and alumina. A peak occurs in the azimuth intensity distribution. The full width at half maximum of this peak was measured, and the degree of orientation was determined from Equation 2 given above. As a result, the carbon fiber was 0.98 in the example of 15% by volume and 0.97 in the example of the 35% by volume. It was.
2. Visual confirmation by microscopic observation of sample For a sample containing 25% by volume of carbon fiber not applied with a magnetic field and a sample containing 25% by volume of carbon fiber applied with a magnetic field, the test piece was cut in the thickness direction, and scanning electron The presence or absence of orientation in the thickness direction of the carbon fiber was observed with a microscope. The micrographs are shown in FIGS. The dark gray part is polyethylene resin and the light gray part is carbon fiber. FIG. 6 shows an example in which no magnetic field is applied, but the direction of the carbon fibers is random. Although FIG. 7 shows an example in which a magnetic field is applied, it can be said that the carbon fibers are regularly oriented in the thickness direction and are well oriented. In addition, the orientation degree calculated | required from the numerical formula 2 mentioned above of the example of carbon fiber which applied the magnetic field 25 volume% mixing | blending was 0.98.

[Examples in which carbon fibers are oriented]
(A) Base material of polyethylene resin Since it was confirmed that carbon fibers could be well oriented in this preliminary test, Examples 1, 2, 3, 5, 6, 12, 13, 14, 15 and comparison Examples 1, 2, 3, 4, and 5 have the same material composition and molding method, but differ only in that the carbon fibers in the base polymer material (polyethylene resin) are oriented by a magnetic field. Examples 1a, 2a, 3a, 5a, 6a, 12a, 13a, 14a, 15a and Comparative Examples 1a, 2a, 3a, 4a, 5a were carried out. In these, the carbon fibers contained are particularly well oriented (the degree of orientation obtained from Equation 2 above is 0.9 to 1).
Orientation by a magnetic field was performed in the same manner as the preliminary test using the apparatus and procedure shown in FIGS. And the test piece taken out from the space 22 of the apparatus 21 was used for the said physical property test. The results are shown in Table 5. In addition, about Example 1a, it measured also about the heat conductivity of the direction orthogonal to the orientation direction of a carbon fiber, and the value was 1.1 W / m * K.

  Moreover, the measurement of the melt flow rate (MFR) of each sample is based on JISK7210-1999, and the brand name "Melt indexer P-001 type" made by Toyo Seiki Seisakusho Co., Ltd. is used. Test temperature: 220 ° C, test Load: 2.16 kgf (21.18 N) The test conditions were used. The results are shown in Table 6 below.

(B) Base material such as resin other than polyethylene resin As in the case of Examples 16 to 43 and Comparative Examples 6 to 8 where the polymer material of the base material is other than polyethylene resin, the material composition and Although the molding method is the same, Examples 16a to 43a and Comparative Examples 6a to 8a which differ only in that the carbon fibers in the polymer material of the base material are oriented by a magnetic field were carried out. In order to orient the carbon fibers, the polypropylene resin sample is heated to 220 ° C., the PPS resin sample is heated to 320 ° C., and the carbon fibers are oriented in a molten state. Silicone rubber and bisphenol A type epoxy resin are Instead of heating and melting, the carbon fibers were oriented in a state before polymerization or the like. The results are shown in Table 7.
The orientation method and physical property test are the same as when the polymer material of the base material is a polyethylene resin.

  Further, measurement of the melt flow rate (MFR) of each sample of Examples 16a to 24a and Comparative Example 6a (the polymer material of the base material is polypropylene resin), and when the polymer material of the base material is a polyethylene resin Under the same conditions, the melt flow rate (MFR) of each of the samples of Examples 25a to 33a and Comparative Example 7a (the base polymer material is PPS resin) was measured at a test temperature of 320 ° C. and a test load of 5 kgf ( 49.03N) (other conditions are the same as for polypropylene resin). Furthermore, each sample of Examples 34a to 42a and Comparative Example 8a (matrix polymer material is silicone rubber) and Example 43a (matrix polymer material is bisphenol A type epoxy resin) before polymerization, etc. The viscosity was measured using an E-type viscometer (Metock Co., Ltd.). The results are shown in Table 7.

[Evaluation of the physical properties]
Each sample using polyethylene resin as the base polymer material had the following results when the carbon fibers were oriented.
All of the Examples ensure both low electrical conductivity (volume resistivity 1 × 10 ² Ω · cm or more) and high heat dissipation (thermal conductivity 0.5 W / m · K or more).
In Examples, high heat dissipation (thermal conductivity) was greatly improved, and low electrical conductivity (volume specific resistance) was somewhat deteriorated, but required performance could be secured. On the other hand, in Comparative Example 2a, the high heat dissipation performance was greatly improved, but the low electrical conductivity was further deteriorated. About the comparative example 3a, the low electrical conductivity deteriorated further.

Each sample using a resin other than the polyethylene resin as the base polymer material has the following effects when the carbon fibers are oriented.
All of the examples ensure both low electrical conductivity (volume resistivity 1 × 10 ² Ω · cm or more) and high heat dissipation (thermal conductivity 0.5 W / m · K or more).
-The example with 15-30 volume% of carbon fiber compounding quantity improved high heat dissipation, and especially the thing of 15-20 volume% of carbon fiber compounding quantity improved the high heat dissipation significantly.
-The low electrical conductivity improved the Example whose compounding quantity of carbon fiber was 15-20 volume% except one part (Example 38, 39).

  The present invention is not limited to the above-described embodiments, and can be modified and embodied as appropriate without departing from the spirit of the invention.

It is a schematic diagram of the low electrical conductivity high heat dissipation high molecular material of the implementation goods of this invention. It is a perspective view which shows the example of the molded object shape | molded with the polymeric material of this invention. It is explanatory drawing which shows the apparatus and method for orienting carbon fiber with a magnetic field. It is explanatory drawing which similarly shows the method of orientating carbon fiber with a magnetic field. It is a graph which shows the measurement result of azimuth intensity distribution by X-ray diffraction. It is a microscope picture of the example of the molded object which does not orientate carbon fiber. It is a microscope picture of the example of the molded object which orientated carbon fiber.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Polymer material 2 Carbon fiber 3 Ceramics 11 Battery pack 12 Insulation plate 13 Battery case 21 Cooling superconducting magnet apparatus 22 Space 23 Electric heater 24 Test piece

Claims (8)

  A low-electric-conductivity, high-heat-dissipating polymer material containing 10 to 35% by volume of carbon fiber and 1 to 20% by volume of ceramic in a polymer material.   The low-conductivity, high heat-dissipating polymer material according to claim 1, wherein the polymer material has a thermal conductivity of less than 1.0 W / m · K.   3. The low electrical conductivity and high heat dissipation polymer material according to claim 1, wherein the polymer material is polyethylene, polypropylene, polyphenylene sulfide, silicone or epoxy resin.   The said ceramic is boron nitride, an alumina, or aluminum nitride, The low electrical conductivity highly heat-dissipating polymeric material as described in any one of Claims 1-3.   The said carbon fiber is a pitch-type carbon fiber, The low electrical conductivity highly heat-dissipating polymeric material as described in any one of Claims 1-4.   The low electrical conductivity high heat dissipation molded object shape | molded with the low electrical conductivity high heat dissipation polymer material as described in any one of Claims 1-5.   The low electrical conductivity high heat dissipation molded article according to claim 6, wherein carbon fibers are oriented in the polymer material.   A molded body or a molded body as a raw material of the molded body is molded with the low electrical conductivity high heat dissipation polymer material according to any one of claims 1 to 5, and the polymeric material of these molded bodies is fluidized. A method for producing a low-electric-conductivity and high-heat-dissipation shaped body, in which carbon fibers in the polymer material are oriented by a magnetic field in a state having a property.