JP2010013521A - Heat conductive silicone composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat conductive silicone composition exhibiting both of good high thermal conductivity and insulating property. <P>SOLUTION: The heat conductive silicone composition has a viscosity of 100 to 1,000 Pas at 25°C before cured, and contains: (A) organopolysiloxane having a specified viscosity and having two or more alkenyl groups bonded to silicon atoms in one molecule; (B) organohydrogenpolysiloxane having two or more SiH groups in one molecule; (C) Al powder having an average particle diameter of 0.5 to 50 μm and an oxygen amount of 0.5 to 5.0 mass%; (E) at least one kind selected from (E1) organosilane expressed by the formula of R<SP>1</SP><SB>a</SB>R<SP>2</SP><SB>b</SB>Si(OR<SP>3</SP>)<SB>4-a-b</SB>and (E2) hydrolyzable methylpolysiloxane having three functional groups at one end shown in the figure; (F) a catalyst selected from a group of platinum and platinum compounds; (G) a reaction controlling agent selected from acetylene compounds, nitrogen compounds, organic phosphorus compounds, oxime compounds and organic chlorine compounds; and (D) heat conductive powder other than the Al powder component (C), having an average particle diameter of 0.1 to 5.0 μm. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a silicone composition excellent in thermal conductivity and insulation.

  Since many electronic components generate heat during use, it is necessary to remove the heat from the electronic components in order for the electronic components to function properly. In particular, an integrated circuit element such as a CPU used in a personal computer has an increased amount of heat generated due to an increase in operating frequency, and countermeasures against heat are an important issue.

  Many methods have been proposed as means for removing this heat. In particular, in an electronic component that generates a large amount of heat, a method for releasing heat by interposing a heat conductive grease or a heat conductive material such as a heat conductive sheet between the electronic component and a member such as a heat sink has been proposed (Patent Document 1). And Patent Document 2).

  Moreover, as this heat conductive material, the thermal radiation grease which mix | blended the zinc oxide and the alumina powder based on silicone oil is known (refer patent document 3 and patent document 4).

  Furthermore, in order to improve the thermal conductivity, the above Patent Document 1 discloses that a liquid organosilicone carrier, silica fiber, dendritic zinc oxide, flaky aluminum nitride and flaky boron nitride are used. A thixotropic heat-conducting material consisting of at least one selected from is disclosed. Patent Document 5 discloses a silicone grease composition obtained by blending a specific organopolysiloxane with a spherical hexagonal aluminum nitride powder having a certain particle size range, and Patent Document 6 discloses a fine particle aluminum nitride powder and particles. A thermally conductive silicone grease combined with a coarse-grained aluminum nitride powder is disclosed in Patent Document 7; a thermally conductive silicone grease combined with an aluminum nitride powder and a zinc oxide powder is disclosed in Patent Document 8; A thermally conductive grease composition using surface-treated aluminum nitride powder is disclosed.

  Aluminum nitride has a thermal conductivity of 70 to 270 W / mK, and diamond having a thermal conductivity of 900 to 2,000 W / mK is a material having a higher thermal conductivity. Patent Document 9 discloses a thermally conductive silicone composition in which diamond, zinc oxide, and a dispersant are blended with a silicone resin.

  In addition, metal is a material having high thermal conductivity, and can be used in places where electronic components do not require insulation. Patent Document 10 discloses a thermally conductive grease composition in which metallic aluminum powder is blended with a base oil such as silicone oil.

  The metallic aluminum powder is very effective in obtaining wettability to silicone oil and the like, so that the filling rate can be easily increased and high heat conduction performance can be obtained. However, since it is a metal powder, it is difficult to use it in places that require insulation. On the other hand, metal powders such as insulating alumina powder and zinc oxide powder, and ceramic powders such as aluminum nitride powder, boron nitride powder, and silicon nitride do not have sufficient wettability with silicone oil, etc. It was difficult to obtain high thermal conductivity compared to the case of using aluminum powder. That is, it has been difficult to obtain a heat conductive silicone composition having both good high heat conductivity and insulating properties.

JP-A-56-28264 JP-A 61-157487 Japanese Patent Publication No.52-33272 Japanese Patent Publication No.59-52195 Japanese Patent Laid-Open No. 2-153955 Japanese Patent Laid-Open No. 3-14873 JP-A-10-110179 JP 2000-63872 A JP 2002-30217 A JP 2000-63873 A

  This invention is made | formed in view of the said situation, and it aims at providing the heat conductive silicone composition which shows both favorable high heat conductivity and insulation.

  As a result of various studies to achieve the above object, the present inventors have determined that the oily organopolysiloxane has an average particle size of 0.5 to 50 μm and an oxygen amount of 0.5 to 5.0 mass%. It has been found that a heat conductive silicone composition obtained by high-filling an aluminum powder having good heat conductivity and insulation has led to the present invention.

That is, the present invention includes the following components (A) to (G):
(A) 100 parts by mass of an organopolysiloxane having at least two alkenyl groups bonded to silicon atoms in one molecule and having a viscosity at 25 ° C. of 10 to 100,000 mm ² / s,
(B) An organohydrogenpolysiloxane having at least two Si—H groups in one molecule {number of Si—H groups} / {number of alkenyl groups in component (A)} is 0.5 to 5.0 ,
(C) 500 to 1300 parts by mass of aluminum powder having an average particle size of 0.5 to 50 μm and an oxygen content of 0.5 to 5.0% by mass;
(E) At least one selected from the following (E1) and (E2):
(E1) Organosilane represented by the following general formula (1):
R ¹ _a R ² _b Si (OR ³ ) _4-ab (1)
Wherein R ¹ is an alkyl group having 9 to 15 carbon atoms, R ² is a hydrocarbon group having 1 to 8 carbon atoms, R ³ is each independently an alkyl group having 1 to 6 carbon atoms, and a is 1 to 1 An integer of 3, b is an integer of 0 to 2, a + b is an integer of 1 to 3) 0.01 to 15 parts by mass, and (E2) one terminal trifunctional hydrolyzable methyl represented by the following general formula (2) Polysiloxane:

・・・（２）

（式中、Ｒ⁴は炭素数１〜６のアルキル基、ｃは５〜１００の整数である）1〜100質量部、
（Ｆ）白金及び白金化合物からなる群より選択される触媒 白金元素として成分（Ａ）の0.1〜500ppmとなる量、及び
（Ｇ）アセチレン化合物、窒素化合物、有機リン化合物、オキシム化合物、及び有機クロロ化合物より選択される少なくとも１種の反応制御剤 0.01〜1質量部
を含む、２５℃での硬化前の粘度が100〜1000Pasである熱伝導性シリコーン組成物である。

... (2)

(Wherein R ⁴ is an alkyl group having 1 to 6 carbon atoms, and c is an integer of 5 to 100) 1 to 100 parts by mass,
(F) a catalyst selected from the group consisting of platinum and platinum compounds, and an amount of 0.1 to 500 ppm of component (A) as platinum element, and (G) acetylene compounds, nitrogen compounds, organophosphorus compounds, oxime compounds, and organic chloro It is a thermally conductive silicone composition having a viscosity of 100 to 1000 Pas at 25 ° C. before curing, comprising 0.01 to 1 part by mass of at least one reaction control agent selected from compounds.

  The thermally conductive silicone composition of the present invention has both good thermal conductivity and insulating properties.

Hereinafter, each component used for the composition of this invention is demonstrated.
[Component (A)]
The organopolysiloxane of component (A) has at least two alkenyl groups directly bonded to silicon atoms in one molecule, and may be linear or branched, or a mixture of two or more of different viscosities. Examples of the alkenyl group include alkenyl groups having 2 to 6 carbon atoms such as vinyl group, allyl group, 1-butenyl group and 1-hexenyl group, but vinyl group is preferable from the viewpoint of ease of synthesis and cost. . Examples of the remaining organic group bonded to the silicon atom include an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, and a dodecyl group; an aryl group such as a phenyl group; a 2-phenylethyl group, and a 2-phenylpropylene group. An aralkyl group such as a chloro group, and a halogen atom-substituted alkyl group such as a chloromethyl group and 3.3.3.-trifluoropropyl group are also exemplified. Among these, a methyl group is preferable from the viewpoint of ease of synthesis and cost. The alkenyl group bonded to the silicon atom may be present at any end of the molecular chain of the organopolysiloxane, but it is preferably at least at the end. The organopolysiloxane preferably has a viscosity at 25 ° C. of preferably 10 to 100,000 mm ² / s, more preferably 100 to 50,000 mm ² / s. When the viscosity is lower than 10 mm ² / s, the storage stability of the resulting composition is deteriorated, and when it is higher than 100,000 mm ² / s, the progress of the obtained composition is deteriorated. The viscosity of the organopolysiloxane is a kinematic viscosity at 25 ° C. measured with an Ostwald viscometer.

[Component (B)]
The organohydrogenpolysiloxane having Si—H groups as component (B) needs to have at least two Si—H groups in one molecule in order to reticulate the composition by crosslinking. Examples of the remaining organic group bonded to the silicon atom include an alkyl group such as a methyl group, an ethyl group, a purpyl group, a butyl group, a hexyl group, and a dodecyl group; an aryl group such as a phenyl group; a 2-phenylethyl group, and 2-phenylpropyl Examples thereof include aralkyl groups such as a group, and further examples include halogen-substituted alkyl groups such as a chloromethyl group and 3.3.3.-trifluoropropyl group. Of these, a methyl group is preferred from the viewpoint of ease of synthesis and cost. Such organopolysiloxane having a Si—H group may be linear, branched or cyclic, or a mixture thereof. The blending amount of component (B) is the number of Si—H groups in component (B) relative to the number of alkenyl groups in component (A), ie {number of Si—H groups} / {in component (A). The number of alkenyl groups in the formula is 0.5 to 5.0, preferably 1.0 to 3.0. If this ratio is less than 0.5, when the composition is cured, a sufficient network structure cannot be obtained, and the necessary hardness after curing cannot be obtained. If the ratio is more than 5.0, a dehydrogenation reaction is likely to occur.

[Component (C)]
The aluminum powder of component (C) has an average particle size in the range of 0.5 to 50 μm, preferably in the range of 1.0 to 30 μm, and more preferably in the range of 1.0 to 20 μm. When the average particle size is less than 0.5 μm, high filling becomes difficult, and when it exceeds 50 μm, the silicone grease becomes non-uniform. In the present invention, the average particle diameter can be obtained as, for example, a volume average diameter (or cumulative average diameter: median diameter) by a laser diffraction method or the like.
The aluminum powder of component (C) also contains oxygen in the range of 0.5 to 5.0% by weight, preferably 0.5 to 3.0% by weight. When the amount of oxygen is less than 0.5% by mass, good insulation is not exhibited, and when it is greater than 5.0% by mass, the wettability with the base oil is deteriorated.
As a method for increasing the amount of oxygen in aluminum, the aluminum powder can be left in a high temperature bath of several hundred degrees to advance the oxidation, or can be left in a high temperature and high humidity using a device such as a constant temperature and humidity chamber. However, the oxygen amount only needs to be within a specific range, and is not limited to these methods. The amount of oxygen can be measured in accordance with JIS Z 2613 inert gas melting-infrared absorption method.
The blending ratio of the aluminum powder is in the range of 500 to 1300 parts by mass, preferably in the range of 600 to 1000 parts by mass with respect to 100 parts by mass of the component (A). If it is less than 500 parts by mass, the resulting composition has insufficient thermal conductivity, whereas if it is greater than 1300 parts by mass, the fluidity of the thermally conductive silicone composition before curing is lost and workability is reduced.

[Component (D)]
In the present invention, in order to further improve the thermal conductivity, as the component (D), a thermal conductive powder having an average particle size other than the above component (C) aluminum powder of 0.1 to 5.0 μm, for example, zinc oxide Inorganic powders such as powder, aluminum oxide powder, boron nitride powder, aluminum nitride powder, and silicon carbide powder may be added. Here, the thermally conductive powder refers to a powder having a thermal conductivity of 5 W / (m · ° C.) or more at room temperature.
When one or more heat conductive powders having an average particle size of 0.1 to 5.0 μm are added, the filling property is improved by entering the gaps between the aluminum powders filled in the silicone. Moreover, it is preferable because the stability of the heat conductive silicone composition of the present invention is improved and oil separation can be prevented. If the average particle size is less than 0.1 μm, the bulk density increases, so that high filling may be difficult, and if it exceeds 5.0 μm, close-packing with a combination with aluminum powder may not be possible. Therefore, the average particle size is preferably in the range of 0.1 to 5.0 μm, more preferably in the range of 0.2 to 3.0 μm.
The blending amount of the heat conductive powder of component (D) is preferably in the range of 0 to 500 parts by weight, more preferably 50 to 500 parts by weight, particularly preferably 100 with respect to 100 parts by weight of component (A). It is the range of -400 mass parts. When the amount is more than 500 parts by mass, the fluidity of the thermally conductive silicone grease composition is lost, and workability may be reduced. In addition, it is preferable that the total compounding quantity of component (C) and (D) is 60-90 volume% in a heat conductive silicone composition, especially 70-85 volume%.

[Ingredient (E)]
Ingredient as a (E), the general ^{_{formula: R 1 a R 2 b Si}} (OR 3) 4-ab (1)
(Wherein R ¹ , R ² , R ³ , a, and b are as previously defined) can be used. Component (A), which is a base oil, has poor wettability with fillers such as components (C) and (D), and if a wetter (wetting improver) is not added and mixed, a sufficient amount of filler is filled. Can not do it. As a result of various studies, it has been found that the amount of the components (C) and (D) can be significantly increased by adding the organosilane of the above general formula.
Specific examples of R ¹ in the above general formula of the organosilane used as a wetter include, for example, alkyl groups having 9 to 15 carbon atoms such as nonyl group, decyl group, dodecyl group, tetradecyl group and the like. If the carbon number of the alkyl group is less than 9, the wettability with the filler is not sufficient, and if it is greater than 15, the organosilane solidifies at room temperature, which is inconvenient to handle and the low temperature characteristics of the resulting composition are low. descend.

A in the above general formula is 1, 2 or 3, and is preferably 1. Although b in the above general formula is 0, 1 or 2, it is preferably 0.
R ² in the above general formula is a saturated or unsaturated monovalent hydrocarbon group having 1 to 8 carbon atoms. Examples of such a group include an alkyl group, a cycloalkyl group, an alkenyl group, an aryl group, and an aralkyl group. Groups, groups obtained by substituting one or more hydrogen atoms of these groups with halogen atoms, and the like. For example, alkyl groups such as methyl group, ethyl group, propyl group, hexyl group and octyl group; cyclohexyl groups such as cyclopentyl group and cyclohexyl group; alkenyl groups such as vinyl group and allyl group; aryl groups such as phenyl group and tolyl group; Aralkyl groups such as 2-phenylethyl group and 2-methyl-2-phenylethyl group; 3,3,3-trifluoropropyl group, 2- (perfluorobutyl) ethyl group, 2- (perfluorooctyl) ethyl group And halogen-substituted alkyl groups such as a p-chlorophenyl group, and a methyl group and an ethyl group are particularly preferable.
R ³ in the above general formula is one or more alkyl groups having 1 to 6 carbon atoms such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group, particularly a methyl group or an ethyl group. Groups are preferred.

Specific examples of the organosilane represented by the general formula (1) include the following:
C ₁₀ H ₂₁ Si (OCH ₃ ) ₃ , C ₁₂ H ₂₅ Si (OCH ₃ ) ₃ , C ₁₀ H ₂₁ Si (CH ₃ ) (OCH ₃ ) ₂ , C ₁₀ H ₂₁ Si (C ₆ H ₆ ) (OCH _{3) 2, C 10 H 21} Si (CH 3) (OC 2 H 5) 2, C 10 H 21 Si (CH = CH 2) (OCH 3) 2, C 10 H 21 Si (CH 2 CH 2 CF 3 ) (OCH ₃ ) ₂ .
The amount of the organosilane of the general formula (1) is preferably in the range of 0.01 to 15 parts by mass, more preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the component (A). If the amount is less than 0.01 parts by mass, the wettability of the component (A) becomes poor, and if it exceeds 15 parts by mass, the effect of the wettability does not increase, which is uneconomical.

  Further, instead of or in combination with the organosilane of the general formula (1), as a wetter component of the components (C) and (D), one-terminal trifunctional hydrolyzable methyl represented by the following general formula (2) Polysiloxanes can be used.

・・・（２）

式（２）中、Ｒ⁴は炭素数１〜６のアルキル基であり、ｃは５〜１００の整数であり、好ましくは１０〜６０の整数である。
この片末端３官能加水分解性メチルポリシロキサンの配合量は、成分（Ａ）100質量部に対して1〜100質量部であることが好ましく、さらに好ましくは20〜50質量部である。1質量部より少ないとウェッター効果が期待できないし、100質量部より多くとも濡れ性の効果の増大は期待できず不経済である。本発明においては、成分（Ｃ）及び（Ｄ）のウエッター成分として、上記一般式（１）で表されるアルコキシシランと一般式（２）で表される片末端３官能加水分解性メチルポリシロキサンとを併用することもできる。

... (2)

In the formula (2), R ⁴ is an alkyl group having 1 to 6 carbon atoms, c is an integer of 5 to 100, preferably 10 to 60 integers.
The blending amount of the one-terminal trifunctional hydrolyzable methylpolysiloxane is preferably 1 to 100 parts by mass, more preferably 20 to 50 parts by mass with respect to 100 parts by mass of the component (A). If the amount is less than 1 part by mass, the wetter effect cannot be expected, and if it exceeds 100 parts by mass, an increase in wettability cannot be expected, which is uneconomical. In the present invention, as the wetter component of components (C) and (D), the alkoxysilane represented by the general formula (1) and the one-terminal trifunctional hydrolyzable methylpolysiloxane represented by the general formula (2) Can also be used in combination.

  When the organosilane of the general formula (1) and the one-terminal trifunctional hydrolyzable methylpolysiloxane of the general formula (2) are used in combination as the component (E), the total amount of the component (E) is the component (A). It is 0.01-50 mass parts with respect to 100 mass parts, Preferably it is 1-40 mass parts.

[Component (F)]
The catalyst selected from platinum of component (F) and a platinum compound is a component for promoting the addition reaction between the alkenyl group of component (A) and the Si—H group of component (B). Examples of the component (F) include platinum alone, chloroplatinic acid, platinum-olefin complexes, platinum-alcohol complexes, and platinum coordination compounds. The compounding quantity of a component (F) is the range of 0.1-500 ppm as a platinum atom with respect to the weight of a component (A). If it is less than 0.1 ppm, there is no effect as a catalyst, and even if it exceeds 500 ppm, no improvement in the curing rate can be expected.

[Component (G)]
The reaction control agent of component (G) suppresses the progress of the hydrosilylation reaction at room temperature and extends shelf life and pot life. Known reaction control agents can be used, and one or more selected from acetylene compounds, various nitrogen compounds, organic phosphorus compounds, oxime compounds, and organic chloro compounds can be used. The compounding quantity of a component (G) is 0.01-1 mass part with respect to 100 mass parts of components (A), Preferably it is the range of 0.01-0.5 mass part. If the amount is less than 0.01 parts by mass, sufficient shelf life and pot life cannot be obtained. If the amount is more than 1 part by mass, the curability decreases.

[Other ingredients]
In the present invention, in addition to the components (A) to (G) described above, if necessary, an adhesion aid or the like may be added to chemically bond and fix the element and the heat radiating body to prevent deterioration. In order to prevent this, an antioxidant may be added.

The heat conductive silicone composition of the present invention can be stored at a low temperature for a long period of time as a one-component addition type by mixing the components (A) to (G). In some cases, this thermally conductive silicone composition can be dispensed by filling a commercially available syringe or cartridge. For this reason, if the viscosity is lower than 100 Pas, dripping occurs at the time of dispensing, and if it is higher than 1000 Pas, the dispensing efficiency is deteriorated. .
The thermally conductive silicone composition of the present invention is cured by heat generated from a heat-generating member such as an element after dispensing, and after curing, the composition has tackiness so that it is not displaced or detached. Further, after the dispensing is mounted, the heat curing may be actively performed.

Hereinafter, the present invention will be described in further detail with reference to examples. First, the following components for forming the composition of the present invention were prepared.
Ingredient (A):
A-1: Dimethylpolysiloxane having both ends blocked with dimethylvinylsilyl groups and a viscosity at 25 ° C. of 600 mm ² / s
A-2: Dimethylpolysiloxane component having both ends blocked with dimethylvinylsilyl groups and a viscosity at 25 ° C. of 30,000 mm ² / s (B):
B-1: Organohydrogenpolysiloxane represented by the following formula

Ingredient (C): The following aluminum powder and zinc oxide powder were mixed at room temperature for 15 minutes at a mixing ratio of the following (Table-1) using a 5 liter planetary mixer (manufactured by Inoue Seisakusho Co., Ltd.). 1-6 were obtained.
C-1: Aluminum powder (average particle size 5.6 μm, oxygen content 2.7 mass%)
C-2: Aluminum powder (average particle size 12.3 μm, oxygen content 0.64 mass%)
C-3: Aluminum powder (average particle size 7.6 μm, oxygen content 0.31 mass%)
C-4: Aluminum powder (average particle size 14.6 μm, oxygen content 7.5% by mass)
C-5: Aluminum powder (average particle size 0.4 μm, oxygen content 3.0 mass%)
C-6: Aluminum powder (average particle size 55.4 μm, oxygen content 0.91 mass%)
Here, the oxygen concentration measurement of a component (C) was performed based on the inert gas melting-infrared absorption method of JISZ2613. OXYGEN / NITROGEN ANALYZER EMGA-523 manufactured by HORIBA, Ltd. was used as the analyzer. Moreover, the average particle diameter of the said component (C) and the following component (D) is a value of the cumulative average diameter (median diameter) measured by Microtrac MT3300EX which is a particle size analyzer made by Nikkiso Co., Ltd.
Ingredient (D)
D-1: Alumina powder (average particle size 1.4 μm)
D-2: Zinc oxide powder (average particle size: 0.5 μm)
D-3: Alumina powder (average particle size 6.5 μm)
Ingredient (E)
E-1: Alkoxysilane C ₁₀ H ₂₁ Si (OCH ₃ ) ₃ represented by the following composition
E-2: Hydrolyzable methylpolysiloxane represented by the following composition formula

成分（Ｆ）
F-1：塩化白金酸のエタノール溶液、白金原子を1％含有
成分（Ｇ）
G-1：1-エチニル-1-シクロヘキサノール
上記成分（Ａ）〜（Ｇ）を以下のように混合して実施例１〜６および比較例１〜８の組成物を得た。即ち、表１又は表２に示す配合量で５リットルプラネタリーミキサー釜（井上製作所（株）社製）にまず成分（Ａ）を取り、これに成分（Ｃ）、（Ｄ）及び（Ｅ)を加え、70℃で1時間混合した。常温になるまで冷却した後、成分（Ｇ）を加えて15分間混合した。次に成分（Ｆ）を加えてまた15分間攪拌し、最後に成分（Ｂ）を加えてさらに30分間混合し、均一な組成物を得た。

Ingredient (F)
F-1: Ethanol solution of chloroplatinic acid, containing 1% platinum atom (G)
G-1: 1-ethynyl-1-cyclohexanol The components (A) to (G) were mixed as follows to obtain compositions of Examples 1 to 6 and Comparative Examples 1 to 8. That is, the component (A) is first taken in a 5-liter planetary mixer kettle (manufactured by Inoue Seisakusho Co., Ltd.) with the blending amounts shown in Table 1 or Table 2, and then the components (C), (D) and (E) And mixed at 70 ° C. for 1 hour. After cooling to room temperature, component (G) was added and mixed for 15 minutes. Next, component (F) was added and stirred again for 15 minutes. Finally, component (B) was added and mixed for another 30 minutes to obtain a uniform composition.

<Test method>
The characteristic of the obtained heat conductive silicone composition was measured with the following test method. The results are shown in Tables 1 and 2.
〔viscosity〕
The thermally conductive silicone grease composition was allowed to stand in a thermostatic chamber at 25 ° C. for 24 hours, and then the viscosity at a rotation speed of 10 rpm was measured using a Malcolm viscometer.
[Method of measuring thermal conductivity]
Each composition was poured into a 6 mm thick mold and heated at 120 ° C. for 1 hour to prepare a sheet-like rubber molded product having a thickness of 6 mm, and then returned to 25 ° C. A total of 24mm thick block pieces were made by stacking four of them. The block pieces were measured with Model QTM-500 manufactured by Kyoto Electronics Industry Co., Ltd.
[Insulation measurement method]
Measurement was performed by a method based on JIS K6249. The adjusted material was poured into a 1 mm thick mold and heated at 120 ° C. for 1 hour to form a 1 mm thick sheet-like molded product, and then returned to 25 ° C. Using this sheet, the volume resistivity of the sheet was measured at a voltage of 500 V using a volume resistance measuring device “4329A HIGH RESISTANCE METER” manufactured by HP (Hewlett-Packard).

The numerical values of components (A) to (G) in the table are parts by mass. Vi is a vinyl group.

表中の成分（Ａ）〜（Ｇ）の数値は質量部である。Viはビニル基である。

The numerical values of components (A) to (G) in the table are parts by mass. Vi is a vinyl group.

  From the results of Tables 1 and 2, it can be seen that the silicone composition of the present invention has both excellent thermal conductivity and insulating properties as compared with the composition of the comparative example.

Claims (4)

The following components (A) to (G):
(A) 100 parts by mass of an organopolysiloxane having at least two alkenyl groups bonded to silicon atoms in one molecule and having a viscosity at 25 ° C. of 10 to 100,000 mm ² / s,
(B) An organohydrogenpolysiloxane having at least two Si—H groups in one molecule {number of Si—H groups} / {number of alkenyl groups in component (A)} is 0.5 to 5.0 ,
(C) 500 to 1300 parts by mass of aluminum powder having an average particle size of 0.5 to 50 μm and an oxygen content of 0.5 to 5.0% by mass;
(E) At least one selected from the following (E1) and (E2):
(E1) Organosilane represented by the following general formula (1):
R ¹ _a R ² _b Si (OR ³ ) _4-ab (1)
Wherein R ¹ is an alkyl group having 9 to 15 carbon atoms, R ² is a hydrocarbon group having 1 to 8 carbon atoms, R ³ is each independently an alkyl group having 1 to 6 carbon atoms, and a is 1 to 1 An integer of 3, b is an integer of 0 to 2, a + b is an integer of 1 to 3) 0.01 to 15 parts by mass, and (E2) one terminal trifunctional hydrolyzable methyl represented by the following general formula (2) Polysiloxane:

... (2)

(Wherein R ⁴ is an alkyl group having 1 to 6 carbon atoms, and c is an integer of 5 to 100) 1 to 100 parts by mass,
(F) a catalyst selected from the group consisting of platinum and platinum compounds, and an amount of 0.1 to 500 ppm of component (A) as platinum element, and (G) acetylene compounds, nitrogen compounds, organophosphorus compounds, oxime compounds, and organic chloro A thermally conductive silicone composition having a viscosity before curing at 25 ° C of from 100 to 1000 Pas, comprising 0.01 to 1 part by mass of at least one reaction control agent selected from compounds.   The component (D) further includes a heat conductive powder having an average particle size of 0.1 to 5.0 μm other than the component (C) aluminum powder in an amount of 500 parts by mass or less. The heat conductive silicone composition as described.   The amount of a component (D) is 50-500 mass parts, The heat conductive silicone composition of Claim 2 characterized by the above-mentioned.   The heat conduction according to claim 2 or 3, wherein the component (D) is at least one selected from the group consisting of zinc oxide powder, aluminum oxide powder, boron nitride powder, aluminum nitride powder and silicon carbide powder. Silicone composition.