JP2010174139A - Thermoconductive resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermoconductive composition which has the rubber-like elasticity and the high thermoconductivity in a plane direction though an elastomer component is filled with a great deal of a carbon fiber. <P>SOLUTION: This thermoconductive composition contains (a) 100 pts.mass of an elastomer component, (b) 50-600 pts.mass of a carbon fiber having an average fiber length of 50-300 μm and an average fiber diameter of 5-15 μm, or of a graphite powder having an average particle diameter of 1-150 μm, (c) 50-500 pts.mass of a ceramics powder having a relatively smaller particle diameter than that of a ceramic powder (d), (d) 0-500 pts.mass of a ceramic powder having a relatively larger particle diameter than that of a metal-based filler or the ceramic powder (c), (e) 0.05-20 pts.mass of a hardener or a vulcanizing agent, wherein a thermal conductivity in a plane direction is 8 or more W/m×K, and the composition is cured. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a heat conductive composition used for heat conductive parts such as electronic parts.

  Electronic parts such as plasma displays, notebook computers, fuel cells, and light emitting diodes (LEDs) may have reduced output and performance when heat is unevenly distributed. Therefore, it is necessary to eliminate uneven distribution of heat (hereinafter referred to as soaking). Since the calorific value in recent years has increased, there has been a demand for heat dissipation of the heat conductive composition that soaks more quickly. Recently, graphite sheets are often used for soaking. In addition, polyphenylene sulfide (PPS) and a compound in which carbon fiber is kneaded into polypropylene are sold, and these processed products may be used. However, graphite has no elasticity, and the sheet shape is limited to a flat surface, and its use is limited. In addition, since a compound obtained by adding or kneading carbon fiber or graphite powder to PPS or polypropylene is hard and brittle, it is difficult to form a thin film. In recent years, therefore, it has been proposed to fill the elastomer with carbon fibers. However, the main purpose is to improve rigidity. Although there is a proposal for improving the thermal conductivity, it is difficult to vulcanize the carbon fiber-added compound, and in addition, it is difficult to highly fill the carbon fiber into the elastomer, so that the thermal conductivity in the plane direction is low. There was a problem. Further, since the graphite powder-containing compound is vulcanized or cured only with a part of the peroxide, the processing method is limited, and the usable elastomer component is also limited.

Various methods have been proposed in the past to solve these problems. Proposal for filling thermoplastic elastomer with carbon fiber (Patent Document 1), Proposal for filling silicone rubber with carbon fiber (Patent Document 2)
Proposal for filling ceramic powder and carbon fiber in combination (Patent Literatures 3 and 4), Proposal for filling thermoplastic elastomer with graphite powder (Patent Literature 5), Proposal for filling silicone rubber with graphite powder (Patent Literature 6) There is a proposal (Patent Document 7) for filling ceramic rubber with a combination of ceramic powder and carbon fiber.

  However, Patent Document 1 is an invention related to a thermoplastic elastomer and its heat dissipation sheet. Since the elastomer is not cured, there is a problem that the heat resistance is not good. Although the modified polyphenylene ether is excellent in heat resistance, there is a problem that it cannot be said to be an elastic body due to poor rubber elasticity.

  Patent Document 2 is an invention relating to a heat conductive silicone rubber in which a predetermined carbon fiber is blended with a silicone rubber, and a heat transfer device thereof. Although there is a regulation of the processing temperature of carbon fiber, there is no description of a technique for facilitating addition to the elastomer, and this method has a problem that the curing reaction of the elastomer is unstable and physical properties are not constant.

  Patent Document 3 is an invention relating to a fiber-reinforced composite material. Although there is a description of a compound using carbon fiber and ceramic powder in combination, it is not an invention in which thermal conductivity is a technical problem. Carbon fiber has a problem that it is difficult to fill the polymer polymer, and further, it is extremely difficult to mix the ceramic powder with the polymer.

  Patent document 4 is a heat-radiation sheet which mix | blends boron nitride and a carbon fiber as a heat conductive filler. Carbon fiber is used as an additive for assisting heat conduction between ceramic powders, and there is a problem that carbon fiber does not act as a main heat conductive material.

  Patent Document 5 is an invention relating to a separator for a fuel cell. As in the case of Patent Document 1, since the elastomer is not cured, there is a problem that the heat resistance is not sufficient.

  Patent Document 6 is an invention relating to a heat dissipation sheet obtained by adding graphite powder to silicone rubber. However, spherical graphite powder called mesocarbon microbeads inhibits the curing mechanism of silicone rubber. There is a problem that the thermal conductivity in the planar direction does not improve even if a large amount is filled.

Patent Document 7 is an invention related to a heat dissipating material in which graphite powder and metal particles are blended with silicone and a method for producing the heat dissipating material. The sheet does not have to be cured because it is a heat-dissipating sheet that is an invention of a heat conductive adhesive, not a heat-dissipating sheet using silicone gel, and is disposed between the heat-generating element and the heat-dissipating element.
JP 2003-113272 A Japanese Patent Laid-Open No. 11-279406 JP-A-8-157620 Japanese Patent Laid-Open No. 2001-110961 JP 2006-156131 A JP-A-10-298433 JP 2002-299534 A

  The present invention provides a heat conductive composition that has rubber elasticity and high thermal conductivity in the plane direction despite the large amount of carbon fiber or graphite powder filled in the elastomer component.

The thermally conductive composition of the present invention is
(A) 100 parts by mass of an elastomer component;
(B) carbon fiber having an average fiber length of 50 to 300 μm, an average fiber diameter of 5 to 15 μm, or 50 to 600 parts by mass of graphite powder having an average particle diameter of 1 to 150 μm;
(C) 50 to 500 parts by mass of ceramic powder having a relatively small particle diameter compared to the ceramic powder (d);
(D) 0 to 500 parts by mass of ceramic powder having a relatively large particle size compared to the metal filler or ceramic powder (c);
(E) It contains 0.05 to 20 parts by mass of a curing agent or a vulcanizing agent, has a thermal conductivity of 8 W / m · K or more in the plane direction, and is cured.

  The present invention can provide a heat conductive composition having rubber elasticity and high thermal conductivity in the plane direction, despite the elastomer component being filled with a large amount of carbon fiber or graphite powder.

FIG. 1A is a cross-sectional view of a U-shaped extruded product according to an embodiment of the present invention, and FIG. 1B is a cross-sectional view in which the extruded product is incorporated into a battery. FIG. 2A is a cross-sectional view of a semi-circular extruded product according to another embodiment of the present invention, and FIG. 2B is a cross-sectional view in which the extruded product is incorporated into a battery. FIG. 3A is a cross-sectional view of a flat extruded product according to another embodiment, and FIG. 3B is a cross-sectional view in which the extruded product is assembled between a heat generating element and a heat sink.

  The component (a) used in the present invention is preferably an elastomer. The elastomer component is at least one elastomer selected from silicone, olefin-based, acrylic-based, fluorine-based, urethane-based and diene-based, and the elastomer may be used alone or a mixture of two or more types can be suitably used. It is also possible to use a partially modified elastomer. Specific examples include silicone-modified acrylic and silicone-modified urethane, but are not limited thereto.

  The component (b) used in the present invention is preferably pitch-based and polyacrylonitrile (PAN) -based carbon fibers, and more preferably pitch-based carbon fibers in consideration of the thermal conductivity in the plane direction. The fiber length distribution is preferably 0.5 μm to 1500 μm, and the average fiber length is preferably 50 to 300 μm. Furthermore, it is preferable that an average fiber diameter is 5-15 micrometers. If the short fiber length is large, the thermal conductivity in the planar direction is lowered. Conversely, if the long fiber length is large, the filling property and workability into the elastomer are deteriorated. The component (b) used in the present invention may be graphite powder having an average particle size of 1 to 150 μm. The graphite powder should have advanced crystallization.

  Carbon fiber or graphite powder is M (OR) n, where M is a 3-6 valent metal atom (preferred metals are Si, Ti, Al, Zr), n is 3-6, R is a methyl group, an ethyl group, n It may be coated with a metal alkoxide which is -propyl group, iso-propyl group, n-butyl group, iso-butyl group, sec-butyl group, tert-butyl group, phenyl group, or a partial hydrolyzate thereof. preferable. The amount of the metal alkoxide is preferably 0.5 to 1.5% by weight of the amount of carbon fiber or graphite powder. If the amount of the metal alkoxide is within the above range, the surface of the carbon fiber or graphite powder can be sufficiently covered with the metal alkoxide, the rubber curability is not affected, and the heat resistance of the cured rubber is not lowered.

  For the treatment of the metal alkoxide on the carbon fiber or graphite powder, the treatment method of the silane coupling agent can be referred to. Treatment methods include dry methods and wet methods. Considering the handling of the metal alkoxide, it is preferable to treat by a wet method. In this method, carbon fiber or graphite powder is placed in a container, the solvent is immersed, a specified amount of metal alkoxide is diluted with the solvent, and this is used as the drug. The drug is dropped into the solution containing the carbon fiber or graphite powder soaked in the solvent. . The solvent used is preferably alcohol. In addition to removing moisture in advance for the containers to be used, depending on the metal alkoxide to be used, it is preferable to proceed while replacing with rare gas. After the solvent-diluted metal alkoxide solution has been added dropwise, the solvent is removed after standing at room temperature for 12 hours or longer. When the solvent is completely removed, for example, heating is performed at 200 ° C. for 2 to 4 hours, and then cooling is performed.

  No baking is performed at 800 to 1000 ° C. as in the sol-gel method. For example, heating at 200 ° C. for 2 to 4 hours will decompose the metal alkoxide. The present invention does not aim to completely convert the metal alkoxide into a metal oxide. It may be a chemical substance in the middle of becoming a metal oxide. It is important to place a decomposition product of metal alkoxide on a cross section or corner where carbon fiber or graphite powder has high activity. This makes it possible to prevent the curing agent or the like from being absorbed, adsorbed or decomposed.

The component (c) used in the present invention is a metal oxide or nitride having an average particle size of 0.02 to 1.5 μm, and is one or a mixture of two or more selected from these, and R (CH ₃ ) silane _{a Si (oR ') 3-} a (R is an unsubstituted or substituted organic group having 6 to 20 carbon atoms, R' is an alkyl group having 1 to 4 carbon atoms, a is 0 or 1) or portions thereof, A ceramic powder coated with a hydrolyzate is preferred. The shape includes a spherical shape, a scale shape, and a polyhedral shape, but any shape may be used as long as the specific surface area is in the range of 0.6 to 80 m ² / g. The specific surface area referred to here is the BET specific surface area, and the measuring method is in accordance with JIS R1626.

  Metal oxides include alumina, zinc oxide, magnesium oxide, silicon oxide, and titanium oxide, nitrides include boron nitride, aluminum nitride, and titanium nitride. Metal oxides include alumina, zinc oxide, and nitride. It is preferable to mix aluminum by selecting one or a mixture of two or more thereof.

The small particle size ceramic powder is R (CH ₃ ) _a Si (OR ′) _{3 -a} (R is an unsubstituted or substituted organic group having 6 to 20 carbon atoms, R ′ is an alkyl group having 1 to 4 carbon atoms, a Is preferably coated with 0 or 1) silane or a partial hydrolyzate thereof. R (CH ₃₎ silane _{a Si (OR ') 3-} a (R is an unsubstituted or substituted organic group having 6 to 20 carbon atoms, R' is an alkyl group having 1 to 4 carbon atoms, a is 0 or 1) One or a mixture of two or more can be preferably used.

R (CH ₃₎ silane _{a Si (OR ') 3-} a (R is an unsubstituted or substituted organic group having 6 to 20 carbon atoms, R' is an alkyl group having 1 to 4 carbon atoms, a is 0 or 1) For hexyltrimethoxylane, hexyltriethoxysilane, octyltrimethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, decyltriethoxysilane, dodecyltrimethoxysilane, dodecyltriethoxysilane, hexadodecyltrimethoxysilane, hexadodecyl There are triethoxy silane, octadecyl trimethoxy silane, octadecyl triethoxy silane and the like, but not limited to those listed here.

  Examples of the coating treatment method include (1) a dry method, (2) a wet method, and (3) an integral blend method. However, the integral blend method is not preferable because it contains many volatile components.

(1) Dry method The dry method is a method in which a surface treatment is performed by dripping a chemical agent on the thermally conductive inorganic powder by mechanical stirring such as a Henschel mixer, a Nauter mixer, or a vibration mill. is there. Examples of the drug include a solution obtained by diluting silane with an alcohol solvent, a solution obtained by diluting silane with an alcohol solvent and further adding water, and a solution obtained by diluting silane with an alcohol solvent and further adding water and an acid. The preparation method of the chemical is described in the catalog of the manufacturer of the silane coupling agent, but which method is selected depends on the silane hydrolysis rate and the type of thermally conductive inorganic powder. Decide.

(2) Wet method The wet method is a method in which a thermally conductive inorganic powder is directly immersed in a drug. Drugs include solutions in which silane is diluted with an alcohol solvent, solutions in which silane is diluted in an alcohol solvent and water is added, and solutions in which silane is diluted with an alcohol solvent and water and acid are added. The method to be selected depends on the hydrolysis rate of silane and the type of thermally conductive inorganic powder.

(3) Integral blend method The integral blend method is a method in which a silane diluted with a stock solution or alcohol is added directly to a mixer when stirring the resin and the thermally conductive inorganic powder, followed by stirring. is there. The method for adjusting the drug is the same as in the dry method and the wet method, but the amount of silane in the case of the integral blend method is generally larger than that in the dry method and the wet method.

  In the dry method and the wet method, the drug is appropriately dried as necessary. When a drug using alcohol or the like is added, it is necessary to volatilize the alcohol. If alcohol eventually remains in the formulation, it will adversely affect the polymer content and will be generated as a gas from the product. The drying temperature is preferably higher than the boiling point of the solvent used. Furthermore, it is preferable to use an apparatus to quickly remove silane that has not reacted with the thermally conductive inorganic powder and heat it to a high temperature. However, considering the heat resistance of the silane, the temperature is below the decomposition point of the silane. It is preferable to keep. The treatment temperature is preferably about 80 to 150 ° C., and the treatment time is preferably 0.5 to 4 hours. The solvent and unreacted silane can be removed by appropriately selecting the drying temperature and time depending on the amount of treatment.

The amount of silane required to treat the surface of the thermally conductive inorganic powder can be calculated by the following equation.
Amount of silane (g) = Amount of thermally conductive inorganic powder (g) × Specific surface area of thermally conductive inorganic powder (m ² / g) / Minimum coverage area of silane (m ² / g)
“Minimum coverage area of silane” is obtained by the following formula.
Minimum covered area of silane (m ² /g)=(6.02×10 ²³ ) × (13 × 10 ⁻²⁰ ) / molecular weight of silane In the above formula, 6.02 × 10 ²³ : Avogadro constant 13 × 10 ⁻²⁰ : Area covered by one molecule of silane (0.13 nm ² )
The necessary amount of silane is preferably 0.5 times or more and less than 1.0 times the amount of silane calculated by this calculation formula. The upper limit is less than 1.0 times because the amount of silane actually present on the surface of the thermally conductive inorganic powder is made smaller than 1.0 in consideration of unreacted components. The reason why the lower limit value is the amount calculated by the above formula is that even when the amount is 0.5 times, the amount is sufficiently effective for improving the heat-conductive inorganic powder filling property into the rubber.

A powder obtained by treating carbon fiber or graphite powder with a metal alkoxide is further converted into R (CH ₃ ) _a Si (OR ′) _{3 -a} (R is unsubstituted or substituted with 6 to 20 carbon atoms) as in the case of small-diameter ceramic powder. Surface treatment may be performed with an organic group, R ′ is an alkyl group having 1 to 4 carbon atoms, a is 0 or 1) silane, or a partial hydrolyzate thereof. The amount of silane at that time is preferably 0.5 to 1.5% by weight. The same processing method as that for the small particle size ceramic powder can be used.

  The metallic filler as component (d) used in the present invention is preferably one or a mixture of two or more selected from gold, silver, copper, platinum, iron, tin, zinc, indium, nickel, and chromium. An alloy selected from the metals listed here may also be used. Further, the large particle size ceramic powder includes metal oxides, nitrides, etc., and the same kind of powder as the small particle size ceramic powder can be used. The shape of the metallic filler as the component (d) or the large particle size ceramic powder includes a spherical shape, a scale shape, and a polyhedral shape, but any shape may be used. The average particle size is preferably 10 to 150 μm. Moreover, a metal filler or a large particle size ceramic powder can be used alone, or a mixture of a metal filler and a large particle size ceramic powder can also be used.

The component (d) used in the present invention is M (OR) n, where M is a trivalent to hexavalent metal atom (preferred metals are Si, Ti, Al, Zr), n is 3 to 6, and R is a methyl group. , Ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, sec-butyl group, tert-butyl group, phenyl alkoxide metal alkoxide, or a partial hydrolyzate thereof R ′ (CH ₃ ) _a Si (OR ″) _{3 -a} (where R ′ is an unsubstituted or substituted organic group having 6 to 20 carbon atoms, R ″ is an alkyl group having 1 to 4 carbon atoms, a May be surface-treated with 0 or 1) silane, or a partial hydrolyzate thereof. However, silane coupling agents, titanium coupling agents, aluminum coupling agents, and zirconium coupling agents are often sufficient. That is, the component (d) only needs to be M (OR) n surface treatment.

  The curing agent or vulcanizing agent as component (e) used in the present invention is a substance that cures the elastomer component. Since the curing form varies depending on the elastomer component, the curing agent needs to be appropriately selected. Also, the amount of curing agent added varies depending on the elastomer used.

  The softener composed of the polymer component is an elastomer component such as naphthenic or paraffinic, and is selected according to the elastomer component selected as appropriate.

  Softeners that are not composed of polymer components such as phosphate esters are not considered to be elastomer components. However, the component that becomes an elastomer upon curing is an elastomer component.

A titanium coupling agent, an aluminum coupling agent, or a zirconium coupling agent may be used as the surface treatment of the thermally conductive inorganic powder, and R (CH ₃ ) _a Si (OR ′) _3-a (R is the number of carbon atoms) 6-20 unsubstituted or substituted organic groups, R ′ is an alkyl group having 1 to 4 carbon atoms, a is 0 or 1) silane is used simultaneously with a thermally conductive inorganic powder treated with one kind or a mixture of two or more kinds. be able to.

  As other additives, pigments, heat-resistant agents, flame retardants and the like may be appropriately added according to the purpose. There are inorganic and organic pigments, but inorganic pigments are preferred from the viewpoint of heat resistance. Specific examples include iron oxide and cobalt oxide, but are not limited thereto. A heat-resistant agent can be suitably selected according to resin. Adoption of phenolic antioxidants, phosphite antioxidants, thioether antioxidants, and metal oxides is safe but not limited to those listed here. Flame retardants include phosphorous, phosphoric acid, metal oxide, carbon, metal hydroxide, etc., and are not limited to those listed here. In any case, one that does not inhibit the curing or vulcanization reaction of the resin and that does not affect the physical properties of the resin component is appropriately selected and blended as one or a mixture of two or more.

  The present invention will be described in detail with reference to examples, but the present invention is not limited to the examples.

(Examples 1-24, Comparative Examples 1-12)
First, surface treatment of carbon fiber or graphite powder was examined. Table 1 shows a list of carbon fibers or graphite powder studied below.

（備考）平均粒径は各社のカタログ値による。なお、平均粒子径はレーザ光散乱法を使用して測定できる。

(Remarks) The average particle size depends on the catalog value of each company. The average particle diameter can be measured using a laser light scattering method.

  Processing is performed as follows. CB-150 is used as the filler and titanium tetraisopropoxide is used as the metal alkoxide as an example, but other carbon fibers or graphite are treated in the same manner.

(Preliminary drying of carbon fiber or graphite powder)
After drying at 110 ° C. for 2 hours in a hot air circulation oven, the product was cooled in a desiccator.

(Metal alkoxide)
Tetraisopropoxytitanium (Wako Pure Chemical Industries)
75% tetra-n-propoxyzirconium solution (Nippon Soda Co., Ltd.)
(Coupling agent)
Hexyltetraethoxysilane (Product name: KBE3063, manufactured by Shin-Etsu Chemical Co., Ltd.)
Isopropyltriisostearoyl titanate (Product name: KR-TTS Ajinomoto Fine Techno Co., Ltd.)
(solvent)
Isopropyl alcohol was prepared by distilling once.

(Treatment with metal alkoxide)
100 parts by mass of CB-150 was charged into a 500 ml Erlenmeyer flask, and 150 parts by mass of isopropyl alcohol which had been distilled off was added. The flask was shaken and stirred until CB-150 was uniformly dispersed. Next, with respect to 1 part by mass of titanium tetraisopropoxide, an agent prepared by diluting 10 parts by mass of distilled isopropyl alcohol was added at once, and the flask was immediately shaken and stirred. Stirring was performed every hour for 4 hours, and then left for 12 hours. After 12 hours, isopropyl alcohol was completely volatilized and dried in a hot air circulating oven at 200 ° C. for 4 hours.

(Treatment with coupling agent)
100 parts by mass of CB-150 treated with metal alkoxide was charged into a 500 ml Erlenmeyer flask, and 150 parts by mass of isopropyl alcohol which had been distilled off was added. The flask was shaken and stirred until CB-150 was uniformly dispersed. Next, 1 mass of hexyltetraethoxysilane was added all at once, and the flask was immediately shaken and stirred. Stirring was performed every hour for 4 hours, and then left for 12 hours. After 12 hours, isopropyl alcohol was completely volatilized.

(Check rubber curability)
Two-part room temperature curable silicone rubber (product name: CF5036, manufactured by Toray Dow Corning) CB-150 treated with a metal alkoxide or metal alkoxide treated with 100 parts by mass of CB- treated with a coupling agent Add 150 parts by weight of 150, knead for 5 minutes while defoaming with a planetary mixer, pour 20g of the kneaded compound into 50cc polypropylene, and heat-treat at 100 ° C for 10 minutes in a hot air circulation oven. And cured.

  The conditions and results of Examples 1 to 24 and Comparative Examples 1 to 12 are summarized in Tables 2 to 4.

表２〜４の実施例１〜２４と比較例１〜１２を比較する。グラファイト又は炭素繊維を金属アルコキシドで処理することによってコンパウンドは硬化する。それに対して処理をしないグラファイト又は炭素繊維を用いたコンパウンドは硬化しない。同様に、シランップリング剤又はチタンカップリング剤で処理したグラファイト又は炭素繊維を用いたコンパウンドも硬化せず、明確な差がでた。しかし、繊維長が長い場合は金属アルコキシドでの処理を行わなくても硬化する。

The Examples 1-24 of Tables 2-4 are compared with Comparative Examples 1-12. The compound is cured by treating graphite or carbon fiber with a metal alkoxide. In contrast, a compound using graphite or carbon fiber that is not treated does not cure. Similarly, a compound using graphite or carbon fiber treated with a silane coupling agent or a titanium coupling agent did not cure and a clear difference was observed. However, when the fiber length is long, it is cured without treatment with a metal alkoxide.

(Examples 25-40, Comparative Examples 13-29)
Next, a system combining graphite or carbon fiber and ceramic powder using the metal alkoxide treated product established in the above experiment will be described. The following materials were used for the study.

(Elastomer component)
Two-component room temperature curable silicone rubber (Product name: CF5036, manufactured by Toray Dow Corning)
Polyisobutylene (Product name: EP200A, manufactured by Kaneka Corporation) Hydrogenated α-olefin (Product name: PAO-5010, manufactured by Idemitsu Kosan Co., Ltd.)
(Crosslinking material)
Methyl hydrogen polysiloxane for silicone (Product name: SE1700 Catalyst Toray Dow Corning) Methyl hydrogen polysiloxane for polyisobutylene (Product name: CR300 manufactured by Kaneka)
(Small particle size ceramic powder)
Alumina with an average particle size of 0.4 μm AL160SG-1 Zinc oxide with an average particle size of 0.4 μm manufactured by Showa Denko Co., Ltd. 1 type of zinc oxide
Copper powder with an average particle size of 20-25 μm Made by Nikko Materials (Large particle size ceramic powder)
Alumina with an average particle size of 22 μm AS20 manufactured by Showa Denko KK (curing agent or vulcanizing agent)
Polyisobutylene curing agent PT-VTSC-3.0IPA Made by Umicore Precious Metals Japan, Inc. (retarder)
Surfynol 61 manufactured by Nissin Chemical Industry Co., Ltd. Small particle size ceramic powder AL160SG-1 and one kind of zinc oxide were treated as follows.

(AL160SG-1)
Required amount of KBE3063 = amount of thermally conductive inorganic powder (g) × specific surface area of thermally conductive inorganic powder (m ² / g) / minimum covering area of silane (m ² / g). Since the minimum covering area of KBE 3063 is 315 m ² / g, it was set to 1000 g × 7.0 m ² / g / 315 m ² /g=22.2 g. KBE 3063: 22.2 g, isopropanol: 40 g, water: 2 g were mixed to give a drug. 1 kg of AL160SG-1 was added to the blender, the drug was added little by little while stirring, stirred for 15 minutes, allowed to stand for 1 day, and dried at 100 ° C. for 2 hours.

(1 type of zinc oxide)
Required amount of KBE3063 = amount of thermally conductive inorganic powder (g) × specific surface area of thermally conductive inorganic powder (m ² / g) / minimum covering area of silane (m ² / g). Since the minimum covering area of KBE 3063 is 315 m ² / g, it was set to 1000 g × 4 m ² / g / 315 m ² /g=12.7 g. KBE 3063: 12.7 g, isopropanol: 20 g, water: 1 g were mixed to give a drug. 1 kg of zinc oxide was added to the blender, the chemical was added little by little while stirring, stirred for 15 minutes, allowed to stand for 1 day, and dried at 100 ° C. for 2 hours.

(Compound creation method)
Carbon fiber or graphite powder, small particle size ceramic powder, metal filler or large particle size ceramic powder, curing agent or vulcanizing agent were added to the polymer component in the planetary mixer and stirred for 10 minutes while defoaming.

(Sheet forming method)
A mold having a thickness of 2 mm was placed on the polyester film subjected to fluorine release treatment, a compound was charged, and another polyester film subjected to fluorine release treatment was placed thereon. This was heated at a pressure of 5 MPa at 120 ° C. for 30 minutes, and then cooled to obtain a heat conductive resin composition.

The CB-100, RA-301, and XN-100N-03Z used in the experiment were those treated in the above examples as shown below.
CB-100: Example 11
RA-301: Example 17
XN-100N-03Z: Example 23
The above conditions and results are summarized in Tables 5-6.

（物性の測定方法）
（ｉ）平面方向の熱伝導率：ホットディスク法（京都電子工業株式会社）熱物性測定装置ＴＰＡ−５０１（製品名）を使用して測定した。この装置の説明は同社のホームページに掲載されている。測定試料は以下のように作成した。各実施例，比較例で記述してあるシート成形方法にて作成した厚み２ｍｍシートを大きさ縦５０ｍｍ×横５０ｍｍにカットし、これを２個用意した。直径７ｍｍのセンサ−を、用意したシートで上下に挟み、冶具にセットした。冶具を挟むトルクは３０Ｎ・ｃｍでおこなった。

(Measurement method of physical properties)
(I) Thermal conductivity in the plane direction: measured using a hot disk method (Kyoto Electronics Industry Co., Ltd.) thermophysical property measuring apparatus TPA-501 (product name). A description of this device can be found on the company's website. The measurement sample was prepared as follows. A sheet having a thickness of 2 mm prepared by the sheet forming method described in each example and comparative example was cut into a size of 50 mm in length and 50 mm in width, and two of them were prepared. A sensor having a diameter of 7 mm was sandwiched between the prepared sheets and set on a jig. The torque between the jigs was 30 N · cm.

As for the measuring method, when set on the jig, the cover attached to the jig was covered so as not to be exposed to the wind and stabilized for 15 minutes. Once stabilized, the measurement was started and the numbers were read. Repeat the same procedure when measuring another sample.
(Ii) Hardness: ASTM D2240 Shore C
(Iii) Viscosity: Precision rotational viscometer Examples 25 to 32 and Comparative Examples 13 and 14, and Examples 33 to 40 and Comparative Examples 21 and 22 are correspondingly compared. Each example product was able to obtain a heat conductive resin composition in which the hardness did not increase so much even when carbon fiber or graphite powder and a small particle size ceramic powder were used in combination. In addition, in the carbon fiber system, the addition of a small particle size ceramic powder has made it possible to determine the viscosity of the compound and to measure the viscosity. This indicates that the compound is not crumbly (keeps viscosity), which indicates that the sheet formability is remarkably improved. Furthermore, Examples 25-32 and Comparative Examples 15-18 are compared with Examples 33-40 and Comparative Examples 23-26. It can be seen that the thermal conductivity in the planar direction is not improved when the addition of the small particle size ceramic powder is small. In particular, carbon fiber systems are particularly effective when used with small-diameter ceramic powders. It can also be seen that the thermal conductivity in the planar direction is improved by using together with carbon fiber or graphite powder regardless of the type of small particle size ceramic powder.

  However, Examples 25-32 and Comparative Examples 17, 18 Corresponding to Examples 33-40 and Comparative Examples 25, 26, as can be seen from the above, if too small ceramic particle powder is added, carbon fibers or In some cases, graphite powder cannot be filled. Further, if the small particle size ceramic powder is not surface-treated as in Comparative Examples 19, 20, 27, and 28, the viscosity of the compound increases and the compound does not harden.

  Comparative Example 29 is a study in which the carbon fiber length is long. If the carbon fiber length is long, the elastomer cannot be filled.

(Examples 41 to 44, Comparative Examples 30 to 34)
Until now, evaluation of a liquid elastomer was performed, but from now on, examples and comparative examples of clay-like elastomers will be described. The following materials were used for the study.

(Elastomer component)
Millable silicone rubber (Product name: TSE201 manufactured by Momentive Performance Materials)
(Crosslinking material)
Crosslinking material for silicone (Product name: TC-25B manufactured by Momentive Performance Materials)
(Small particle size ceramic powder)
Alumina with an average particle size of 0.4 μm AL160SG-1 Zinc oxide with an average particle size of 0.4 μm manufactured by Showa Denko Co., Ltd. 1 type of zinc oxide
Copper powder with an average particle size of 20-25 μm Made by Nikko Materials (curing agent or vulcanizing agent)
Hardener for silicone (TC-25A manufactured by Momentive Performance Materials)
(Compound creation method)
Carbon fiber or graphite powder, small particle size ceramic powder, metal filler, curing agent or vulcanizing agent was added to the polymer component with two rolls and stirred for 10 minutes.

(Sheet forming method)
A 2 mm thick mold was placed on the polyester film that had been subjected to fluorine release treatment, a compound was charged, and another polyester film that had been subjected to fluorine release treatment was placed thereon. This was temporarily molded at a pressure of 5 MPa at 25 ° C. for 1 minute. The preliminarily molded sheet was heated in a hot air circulation oven set at 120 ° C. for 30 minutes, taken out and cooled to obtain a heat conductive resin composition.

実施例４１〜４４と比較例３０〜３１を比較する。グラファイト粉又は炭素繊維を表面処理しないとエラストマーの硬化が不充分になることがわかる。

Examples 41-44 and Comparative Examples 30-31 are compared. It can be seen that if the graphite powder or carbon fiber is not surface treated, the elastomer will be insufficiently cured.

  Further, as can be seen from the comparison between Examples 41 to 44 and Comparative Examples 32 to 35, the combination of carbon fiber or graphite powder and small particle size ceramic powder is more flat than the case where no small particle size ceramic powder is used in combination. Directional thermal conductivity is improved. However, if too small a ceramic particle powder is added, carbon fiber or graphite powder cannot be filled. It can be seen that it is important that the small particle size ceramic powder is in an appropriate amount.

(Examples 45-46, Comparative Examples 36-41)
Next, the elastomer component was examined using polyisobutylene.

(Elastomer component)
Polyisobutylene (Product name: EP200A manufactured by Kaneka Corporation)
Hydrogenated α-olefin (Product name: PAO-5010, manufactured by Idemitsu Kosan Co., Ltd.)
(Crosslinking material)
Methyl hydrogen polysiloxane for polyisobutylene (Product name: CR300 manufactured by Kaneka Corporation)
(Small particle size ceramic powder)
Alumina with an average particle size of 0.4 μm AL160SG-1 Zinc oxide with an average particle size of 0.4 μm manufactured by Showa Denko Co., Ltd. 1 type of zinc oxide manufactured by Hakusuitec Co., Ltd. Processed. The processing method was the same as in the previous example.

(Metal filler)
Copper powder with an average particle size of 20-25 μm Made by Nikko Materials (curing agent or vulcanizing agent)
Polyisobutylene curing agent PT-VTSC-3.0IPA Made by Umicore Precious Metals Japan, Inc. (retarder)
Surfynol 61 manufactured by Nissin Chemical Industry (compound preparation method)
Carbon fiber or graphite powder, small particle size ceramic powder, large particle size ceramic powder, curing agent or vulcanizing agent were added to the planetary mixer as polymer components and stirred for 5 minutes while defoaming.

(Sheet forming method)
A 2 mm-thick mold is placed on the polyester film that has been subjected to fluorine release treatment, a compound is charged, and another polyester film that has been subjected to fluorine release treatment is placed thereon. This was heated at a pressure of 5 MPa at 120 ° C. for 30 minutes and then cooled to obtain a heat conductive resin composition.

  Table 8 shows the above conditions and results.

測定方法は前記実施例同様でおこなった。可塑度についてはウォーレス可塑度計を用いて測定した。

The measurement method was the same as in the previous example. The plasticity was measured using a Wallace plasticity meter.

  Comparing Examples 45 and 46 with Comparative Examples 36 and 37, it can be seen that unless the small particle size ceramic powder is surface-treated, the viscosity of the compound increases and the compound does not harden. When Examples 45 and 46 are compared with Comparative Examples 38 to 41, it is understood that the elastomer is not sufficiently cured unless the graphite powder or the carbon fiber is surface-treated.

  From the above examples, the carbon fiber or the graphite powder-containing elastomer can be cured by treating the carbon fiber or the graphite powder with a metal alkoxide. In addition, by adding a small particle size ceramic powder surface-treated with silane, the thermal conductivity in the planar direction was improved, and the compound was no longer crisp, and the compound became cohesive. Especially in the case of carbon fiber, the effect was great. In addition, it became possible to perform extrusion molding by making it possible to cure with a platinum catalyst.

  Extrusion molding was performed using the compound (formulation) of Example 45. The shape is shown in FIGS. 1A is a cross-sectional view of a U-shaped extrudate 1, FIG. 1B is a cross-sectional view in which the extrudate 1 is incorporated in a battery 2, FIG. 2A is a cross-sectional view of a semicircular extrudate 3, and FIG. 3A is a cross-sectional view of the flat extruded product 6, and FIG. 3B is a cross-sectional view of the extruded product 6 assembled between the heating element 5 and the heat sink 7. The example product of the present invention is suitable for such a use, and is also useful as a heat conductive sheet from a general heating element.

  The heat conductive resin composition of the present invention is useful as a heat conductive sheet for heat-generating electronic components such as plasma displays, notebook computers, game machines, fuel cells, and light emitting diodes (LEDs).

1 U-shaped extruded product 2, 4 Battery 3 Semi-circular extruded product 5 Heating element 6 Flat extruded product 7 Heat sink

Claims (13)

(A) 100 parts by mass of an elastomer component;
(B) carbon fiber having an average fiber length of 50 to 300 μm, an average fiber diameter of 5 to 15 μm, or 50 to 600 parts by mass of graphite powder having an average particle diameter of 1 to 150 μm;
(C) 50 to 500 parts by mass of ceramic powder having a relatively small particle diameter compared to the ceramic powder (d);
(D) 0 to 500 parts by mass of ceramic powder having a relatively large particle size compared to the metal filler or ceramic powder (c);
(E) A thermally conductive resin composition comprising 0.05 to 20 parts by mass of a curing agent or a vulcanizing agent, having a thermal conductivity in a plane direction of 8 W / m · K or more and being cured. .   The thermally conductive resin composition according to claim 1, wherein the component (a) is at least one selected from a thermosetting resin, a thermoplastic resin, and rubber.   The thermally conductive resin composition according to claim 1, wherein the component (a) is silicone rubber.   The component (b) is M (OR) n, where M is a trivalent to hexavalent metal atom, n is 3 to 6, R is a methyl group, ethyl group, n-propyl group, iso-propyl group, n- The heat conductive resin composition of Claim 1 currently surface-treated with the metal alkoxide which is a butyl group, iso-butyl group, sec-butyl group, tert-butyl group, a phenyl group, or its partial hydrolyzate. The component (b) is R ′ (CH ₃ ) _a Si (OR ″) _3-a (wherein R ′ is an unsubstituted or substituted organic group having 6 to 20 carbon atoms) after the surface treatment of claim 4. The thermally conductive resin composition according to claim 1, wherein R ′ is a surface treatment with a C 1-4 alkyl group, a is 0 or 1) silane, or a partial hydrolyzate thereof.   The said (a) component is a thermosetting resin, The heat conductive resin composition of Claim 2 containing a vulcanizing agent and / or a hardening | curing agent.   The thermally conductive resin composition according to claim 3, wherein the component (a) is a silicone rubber and is cured with a platinum catalyst.   The heat conductive resin composition according to claim 1, wherein the heat conductive resin composition can be extruded.   The thermally conductive resin composition according to claim 1, wherein the component (c) is at least one selected from metal oxides and nitrides having an average particle size of 0.02 to 1.5 μm.   The metal oxide is at least one selected from alumina, zinc oxide, magnesium oxide, silicon oxide, and titanium oxide, and the nitride is at least one selected from boron nitride, aluminum nitride, and titanium nitride. Thermally conductive resin composition. Wherein component _{(c), R (CH 3) a Si} (OR ') 3-a (R is an unsubstituted or substituted organic group having 6 to 20 carbon atoms, R' is an alkyl group having 1 to 4 carbon atoms, a The thermally conductive resin composition according to claim 1 or 9, which is coated with 0 or 1) silane, or a partial hydrolyzate thereof.   The thermally conductive resin according to claim 1, wherein the component (d) is at least one selected from gold, silver, copper, platinum, iron, tin, zinc, indium, nickel and chromium having an average particle diameter of 10 to 150 µm. Composition. The component (d) is M (OR) n, where M is a 3-6 valent metal atom, n is 3-6, R is a methyl group, ethyl group, n-propyl group, iso-propyl group, n- The heat conductive resin composition of Claim 1 or 12 surface-treated with the metal alkoxide which is a butyl group, iso-butyl group, sec-butyl group, tert-butyl group, a phenyl group, or its partial hydrolyzate. object.

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