JP7476795B2 - Addition-curable silicone composition - Google Patents

Description

The present invention relates to an addition-curable silicone composition. In particular, the present invention relates to an addition-curable silicone composition with high thermal conductivity, and an addition-curable silicone composition with good adhesion to the surface of precious metals such as gold.

It is widely known that electronic components such as LSIs and IC chips generate heat during use, which leads to a decrease in performance, and various heat dissipation technologies are used as a means to solve this problem. A common heat dissipation technology is to place a cooling member near the heat-generating part, bring the two into close contact, and then dissipate heat by efficiently removing the heat from the cooling member.

In this case, if there is a gap between the heat-generating component and the cooling component, the air with poor thermal conductivity will be trapped, reducing the thermal conductivity and preventing the temperature of the heat-generating component from dropping sufficiently. To prevent this air from being trapped and improve the thermal conductivity, heat-dissipating materials with good thermal conductivity and conformability to the surface of the component, such as heat-dissipating grease and heat-dissipating sheets, are used (Patent Documents 1 to 11: Japanese Patent No. 2938428, Japanese Patent No. 2938429, Japanese Patent No. 3580366, Japanese Patent No. 3952184, Japanese Patent No. 4572243, Japanese Patent No. 4656340, Japanese Patent No. 4913874, Japanese Patent No. 4917380, Japanese Patent No. 4933094, Japanese Patent No. 5283346, Japanese Patent No. 5233325).

For example, Patent Document 9 discloses a thermally conductive silicone grease composition containing an organopolysiloxane having a specific structure, an alkoxysilane having a specific substituent, and a thermally conductive filler, and describes that the composition has good thermal conductivity, good fluidity, and excellent workability. Patent Documents 10 and 11 disclose a sheet having adhesiveness and thermal conductivity, and disclose a thermally conductive composition in which an addition-curing silicone rubber composition is blended with a thermally conductive filler and a silicone resin having no aliphatic unsaturated hydrocarbon group. Patent Documents 10 and 11 disclose that a thermally conductive cured product having appropriate adhesiveness and good thermal conductivity in a thin film state can be provided.

Some heat dissipation greases are given adhesive properties to firmly bond the semiconductor chip and the heat spreader. If the semiconductor chip and the heat spreader are not sufficiently bonded through the grease, the heat dissipation performance will not be fully exerted, resulting in a significant decrease in performance. Therefore, it is important to firmly bond the semiconductor chip and the heat spreader with the grease. On the other hand, in order to improve the thermal conductivity of the heat dissipation grease, it is also necessary to fill a large amount of thermally conductive filler. If a large amount of thermally conductive filler is filled into the grease, the amount of organic components will relatively decrease, resulting in a problem of reduced adhesiveness of the resulting cured product. If the adhesiveness decreases, the cured product will not be able to follow the distortion of the semiconductor chip due to the thermal history of heating and cooling, causing peeling, and in the worst case, the semiconductor chip may be damaged. For example, Patent Document 12 (Patent Publication No. 6149831) discloses a thermally conductive silicone grease composition that contains an organohydrogenpolysiloxane of a specific structure and has good adhesiveness to metal silicon and nickel surfaces.

On the other hand, in recent years, semiconductor devices in which precious metals such as gold are vapor-deposited on the surfaces of semiconductor chips or heat spreaders are sometimes provided in order to improve the reliability of the semiconductor devices. It is known that addition-curing silicone compositions may fail to cure on surfaces on which precious metals such as gold are vapor-deposited, and in such cases, there is a problem in that the adhesive strength of compositions that have been given adhesive properties is significantly reduced.

Patent Document 13 (Japanese Patent No. 5,447,337) discloses a thermally conductive silicone composition that can be bonded to a gold-vapor-deposited surface by using a peroxide with a 10-hour half-life temperature of 80°C or higher and lower than 130°C as a curing agent; however, the adhesive strength is weak and is not at a level sufficient to firmly bond a semiconductor chip and a heat spreader.

Patent Document 14 (JP Patent Publication 2008-106185 A) discloses a thermally conductive silicone composition that can be bonded to a gold-deposited surface by treating the precious metal surface with a primer that contains a platinum-based compound and a solvent but does not contain an alkoxysilane. However, as with Patent Document 13, the adhesive strength is weak and is not at a level that can firmly bond the semiconductor chip and the heat spreader. Furthermore, treatment with a primer is not preferred because it complicates the process and is uneconomical.

As mentioned above, in recent years, emphasis has been placed on improving the reliability of semiconductor devices, and one method of achieving this is to vapor-deposit precious metals such as gold onto the surfaces of semiconductor chips and heat spreaders. However, conventional silicone thermal greases have the problem that they are unable to exhibit sufficient adhesion on surfaces that have been vapor-deposited with precious metals such as gold. There is a demand for silicone thermal greases that exhibit good adhesion even on such surfaces.

Japanese Patent No. 2938428 Patent No. 2938429 Japanese Patent No. 3580366 Patent No. 3952184 Patent No. 4572243 Japanese Patent No. 4656340 Patent No. 4913874 Patent No. 4917380 Japanese Patent No. 4933094 Patent No. 5283346 Patent No. 5233325 Patent No. 6149831 Patent No. 5447337 JP 2008-106185 A

Therefore, the present invention has been made in consideration of the above circumstances, and aims to provide an addition-curing silicone composition that has better adhesion to surfaces vapor-deposited with precious metals such as gold than conventional silicone thermal greases.

As a result of intensive research conducted by the inventors in order to achieve the above object, they discovered that by blending specific amounts of an aliphatically unsaturated hydrocarbon group-containing organopolysiloxane, a thermally conductive filler, an organohydrogenpolysiloxane, a hydrolyzable organosilane compound having a specific structure and containing sulfur atoms, a platinum group metal catalyst, and, if necessary, a silicone resin having an aliphatically unsaturated hydrocarbon group, it is possible to obtain an addition-curable silicone composition that can exhibit good adhesion even on surfaces onto which precious metals such as gold have been vapor-deposited, and this led to the creation of the present invention.

（式中、Ｒ¹は置換基を有していてもよい炭素数１～１０の１価炭化水素基を表し、それぞれのＲ¹は同一であっても異なっていてもよい。Ｒ²はそれぞれ独立に非置換もしくは置換の炭素数１～２０のアルキル基、非置換もしくは置換の炭素数６～１０のアリール基、炭素数７～１０のアラルキル基、非置換もしくは置換の炭素数２～１０のアルケニル基、又は非置換もしくは置換の炭素数１～２０のアルコキシ基であり、Ｒ³は非置換もしくは置換の炭素数１～１０のアルキル基、又は非置換もしくは置換の炭素数６～１０のアリール基であり、ｎは１～３の整数であり、ｍは１～１２の整数である。）
（Ｆ）白金族金属触媒： 有効量
を必須成分とする付加硬化型シリコーン組成物。
［２］．
さらに、（Ｇ）反応制御剤を（Ａ）成分と（Ｂ）成分の合計１００質量部に対して０．０５～５質量部含む［１］に記載の付加硬化型シリコーン組成物。
［３］．
さらに、（Ｈ）パーオキシケタール、ハイドロパーオキサイド、ジアルキルパーオキサイド、ジアシルパーオキサイド、パーオキシエステル、及びパーオキシジカーボネートから選ばれる有機過酸化物を（Ａ）成分と（Ｂ）成分の合計１００質量部に対して０．０１～１０質量部含む［１］又は［２］に記載の付加硬化型シリコーン組成物。
［４］．
さらに、（Ｉ）下記一般式（２）で示される加水分解性オルガノシラン化合物を（Ａ）成分と（Ｂ）成分の合計１００質量部に対して０．１～３０質量部含む［１］～［３］のいずれかに記載の付加硬化型シリコーン組成物。

（式中、Ｒ¹は置換基を有していてもよい炭素数１～１０の１価炭化水素基を表し、それぞれのＲ¹は同一であっても異なっていてもよい。Ｒ⁴はエポキシ基、アクリロイル基、メタクリロイル基、アルコキシシリル基から選択される基である。Ｘはヘテロ原子を含んでもよい炭素数１～２０のアルキレン基である。ａは０～２の整数である。）
［５］．
さらに、（Ｊ）下記一般式（３）で表される加水分解性オルガノポリシロキサン化合物を（Ａ）成分と（Ｂ）成分の合計１００質量部に対して１～２００質量部含む［１］～［４］のいずれかに記載の付加硬化型シリコーン組成物。

（式中、Ｒ¹は置換基を有していてもよい炭素数１～１０の１価炭化水素基を表し、それぞれのＲ¹は同一であっても異なっていてもよい。ｂは５～１００の整数である。）
［６］．
さらに、（Ｋ）下記一般式（４）で表される加水分解性オルガノポリシロキサン化合物を（Ａ）成分と（Ｂ）成分の合計１００質量部に対して１～５０質量部含む［１］～［５］のいずれかに記載の付加硬化型シリコーン組成物。

（式中、Ｒ¹は置換基を有していてもよい炭素数１～１０の１価炭化水素基を表し、それぞれのＲ¹は同一であっても異なっていてもよい。Ｒ⁵は炭素数２～６のアルケニル基である。ｐ、ｑは１≦ｐ≦５０、１≦ｑ≦９９、５≦ｐ＋ｑ≦１００を満足する数である。） Accordingly, the present invention provides the following addition-curable silicone composition.
[1]
(A) an organopolysiloxane having at least two aliphatic unsaturated hydrocarbon groups in one molecule and having a kinetic viscosity at 25° C. of 60 to 100,000 mm ² /s: 100 parts by mass,
(B) a silicone resin having at least one aliphatic unsaturated hydrocarbon group per molecule: 0 to 100 parts by mass per 100 parts by mass of component (A),
(C) at least one thermally conductive filler selected from the group consisting of metals, metal oxides, metal hydroxides, metal nitrides, metal carbides, and allotropes of carbon: in an amount of 10 to 95% by mass based on the total mass of the composition;
(D) an organohydrogenpolysiloxane having two or more hydrogen atoms bonded to silicon atoms per molecule: an amount such that the number of SiH groups relative to the total number of aliphatic unsaturated hydrocarbon groups in components (A) and (B) is 0.5 to 5;
(E) a hydrolyzable organosilane compound represented by the following general formula (1): 0.1 to 10 parts by mass per 100 parts by mass of the total of the components (A) and (B),

(In the formula, R ¹ represents a monovalent hydrocarbon group having 1 to 10 carbon atoms which may have a substituent, and each R ¹ may be the same or different. Each R ² is independently an unsubstituted or substituted alkyl group having 1 to 20 carbon atoms, an unsubstituted or substituted aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 10 carbon atoms, an unsubstituted or substituted alkenyl group having 2 to 10 carbon atoms, or an unsubstituted or substituted alkoxy group having 1 to 20 carbon atoms; R ³ represents an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms, or an unsubstituted or substituted aryl group having 6 to 10 carbon atoms; n is an integer from 1 to 3; and m is an integer from 1 to 12.)
(F) Platinum group metal catalyst: An addition-curable silicone composition containing an effective amount of a platinum group metal catalyst as an essential component.
[2]
The addition-curable silicone composition according to [1], further comprising 0.05 to 5 parts by mass of a reaction inhibitor (G) per 100 parts by mass of the combined total of the components (A) and (B).
[3]
The addition-curable silicone composition according to [1] or [2] further comprises (H) 0.01 to 10 parts by mass of an organic peroxide selected from a peroxyketal, a hydroperoxide, a dialkyl peroxide, a diacyl peroxide, a peroxy ester, and a peroxydicarbonate, per 100 parts by mass of the combined total of the components (A) and (B).
[4]
The addition-curable silicone composition according to any one of [1] to [3], further comprising: (I) 0.1 to 30 parts by mass of a hydrolyzable organosilane compound represented by the following general formula (2), per 100 parts by mass of the total of the components (A) and (B):

(In the formula, ^R1 represents a monovalent hydrocarbon group having 1 to 10 carbon atoms which may have a substituent, and each ^R1 may be the same or different. ^R4 represents a group selected from an epoxy group, an acryloyl group, a methacryloyl group, and an alkoxysilyl group. X represents an alkylene group having 1 to 20 carbon atoms which may contain a heteroatom. a represents an integer of 0 to 2.)
[5]
The addition-curable silicone composition according to any one of [1] to [4], further comprising (J) 1 to 200 parts by mass of a hydrolyzable organopolysiloxane compound represented by the following general formula (3), per 100 parts by mass of the total of the components (A) and (B):

(In the formula, R ¹ represents a monovalent hydrocarbon group having 1 to 10 carbon atoms which may have a substituent, and each R ¹ may be the same or different, and b is an integer of 5 to 100.)
[6]
The addition-curable silicone composition according to any one of [1] to [5], further comprising (K) 1 to 50 parts by mass of a hydrolyzable organopolysiloxane compound represented by the following general formula (4), per 100 parts by mass of the total of the components (A) and (B):

(In the formula, ^R1 represents a monovalent hydrocarbon group having 1 to 10 carbon atoms which may have a substituent, and each ^R1 may be the same or different. ^R5 represents an alkenyl group having 2 to 6 carbon atoms. p and q are numbers which satisfy 1≦p≦50, 1≦q≦99, and 5≦p+q≦100.)

The addition-curable silicone composition of the present invention has good adhesion to surfaces on which precious metals such as gold are vapor-deposited. In other words, it can be applied to semiconductor devices in which precious metals such as gold are vapor-deposited on the surfaces of semiconductor chips and heat spreaders to improve reliability.

The present invention will be described in detail below.
Component (A)
Component (A) is an organopolysiloxane having at least 2, preferably 2 to 100, and more preferably 2 to 50 aliphatic unsaturated hydrocarbon groups in each molecule and having a kinematic viscosity at 25° C. of 60 to 100,000 mm ² /s.

The aliphatic unsaturated hydrocarbon group is preferably a monovalent hydrocarbon group having an aliphatic unsaturated bond and having 2 to 8 carbon atoms, more preferably 2 to 6 carbon atoms, and is more preferably an alkenyl group. Examples of alkenyl groups include vinyl groups, allyl groups, propenyl groups, isopropenyl groups, butenyl groups, hexenyl groups, cyclohexenyl groups, and octenyl groups. Vinyl groups are particularly preferred. The aliphatic unsaturated hydrocarbon group may be bonded to either a silicon atom at the molecular chain terminal or a silicon atom in the middle of the molecular chain, or may be bonded to both.
The organopolysiloxane of component (A) preferably has an aliphatic unsaturated hydrocarbon group content per molecule of 0.00001 to 0.01 mol/g, and particularly preferably 0.0001 to 0.01 mol/g.

The organic group other than the aliphatic unsaturated hydrocarbon group bonded to the silicon atom of the organopolysiloxane is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms, and more preferably 1 to 8 carbon atoms, and having no aliphatic unsaturated bonds. Examples include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, octyl, nonyl, and decyl; aryl groups such as phenyl, tolyl, xylyl, and naphthyl; aralkyl groups such as benzyl, phenylethyl, and phenylpropyl; and groups in which some or all of the hydrogen atoms of these groups have been substituted with halogen atoms such as fluorine, bromine, and chlorine, or cyano groups, such as chloromethyl, chloropropyl, bromoethyl, trifluoropropyl, and cyanoethyl. In particular, a methyl group is preferable.

The organopolysiloxane has a kinetic viscosity of 60 to 100,000 mm ² /s, and preferably 100 to 30,000 mm ² /s, at 25° C. If the kinetic viscosity is less than 60 mm ² /s, the physical properties of the silicone composition will be impaired, whereas if it exceeds 100,000 mm ² /s, the extensibility of the silicone composition will be poor.
In the present invention, the kinematic viscosity is a value measured at 25° C. using an Ubbelohde-type Ostwald viscometer (the same applies hereinafter).

The molecular structure of the organopolysiloxane is not particularly limited as long as it has the above properties, and examples thereof include a linear structure, a branched structure, and a linear structure having a partially branched structure or a cyclic structure. In particular, it is preferable that the main chain is composed of a repeating diorganosiloxane unit and has a linear structure in which both ends of the molecular chain are blocked with triorganosiloxy groups. The organopolysiloxane having the linear structure may also have a partially branched structure or a cyclic structure.

The organopolysiloxanes may be used alone or in combination of two or more.

Component (B) Component (B) is a silicone resin. The silicone resin of component (B) has at least one aliphatic unsaturated hydrocarbon group in one molecule. Component (B) does not have to be blended, but when the silicone resin of component (B) is contained, the adhesive strength of the cured product obtained from the addition curing silicone composition of the present invention can be improved.

In the present invention, component (B) is preferably ^a silicone _resin containing SiO4 _/2 units, ^R62R7SiO1 _/ 2 units, and ^R63SiO1 _{/2 units} (wherein ^R6 is each independently a monovalent hydrocarbon group that does not have an aliphatic unsaturated bond, and ^R7 is a monovalent aliphatic unsaturated hydrocarbon group).

In the formula, R ⁶ is independently an unsubstituted or substituted monovalent hydrocarbon group having 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms, and more preferably 1 to 8 carbon atoms, and does not have an aliphatic unsaturated bond. Examples of R ⁶ include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, octyl, nonyl, and decyl; aryl groups such as phenyl, tolyl, xylyl, and naphthyl; aralkyl groups such as benzyl, phenylethyl, and phenylpropyl; and groups in which some or all of the hydrogen atoms of these groups have been substituted with halogen atoms such as fluorine, bromine, and chlorine, or cyano groups, such as chloromethyl, chloropropyl, bromoethyl, trifluoropropyl, and cyanoethyl. Among these, a methyl group is particularly preferred.

^R7 is a monovalent aliphatic unsaturated hydrocarbon group, preferably a monovalent hydrocarbon group having an aliphatic unsaturated bond and having 2 to 8 carbon atoms, more preferably 2 to 6 carbon atoms, and more preferably an alkenyl group. Examples of the alkenyl group include a vinyl group, an allyl group, a propenyl group, an isopropenyl group, a butenyl group, a hexenyl group, a cyclohexenyl group, and an octenyl group. A vinyl group is particularly preferred.

The silicone resin of component (B) has at least one aliphatic unsaturated hydrocarbon group per molecule, preferably 1×10 ⁻⁵ to 1×10 ⁻² mol/g, and more preferably 1×10 ⁻⁴ to 2×10 ⁻³ mol/g.

Furthermore, in component (B), the molar ratio of SiO _4/2 units (Q units) to R ⁶ ₂ R ⁷ SiO _1/2 units and R ⁶ ₃ SiO _1/2 units (M units) is preferably such that (M units)/(Q units) is a number that satisfies 0.1 to 3, more preferably such that (M units)/(Q units) is a number that satisfies 0.3 to 2.5, and particularly preferably such that (M units)/(Q units) is a number that satisfies 0.5 to 2. When the molar ratio of M units to Q units is within the above range, a grease with good adhesiveness and strength can be provided. The silicone resin according to the present invention may contain R ₂ SiO _2/2 units (D units) and RSiO _3/2 units (T units) in the molecule to an extent that does not impair the properties of the addition-curable silicone composition of the present invention (for example, 1 to 50 mol % in the silicone resin of component (B)) (wherein R is R ⁶ or R ⁷ ).

The silicone resin used in the present invention is a solid or viscous liquid at room temperature. There are no particular limitations on the average molecular weight of the silicone resin, but it is preferable that the molecular weight be such that the kinetic viscosity of the silicone resin when dissolved in xylene to form a 50% by mass solution is 0.5 to ¹⁰ mm2/s, preferably 1 to 5 ^mm2 /s. Having the kinetic viscosity of the silicone resin within the above range is preferable because it is possible to prevent a decrease in the physical properties of the composition.

The amount of silicone resin in component (B) is 0 to 100 parts by mass per 100 parts by mass of component (A), but if it is blended, it is preferably 1 to 100 parts by mass, and more preferably 3 to 50 parts by mass. If the amount of component (B) is less than the above lower limit, it may be insufficient to exhibit adhesive properties, and if it is more than the above upper limit, it may result in poor extensibility.

Component (C) Component (C) is one or more thermally conductive fillers selected from the group consisting of metals, metal oxides, metal hydroxides, metal nitrides, metal carbides, and allotropes of carbon. Examples include aluminum, silver, copper, metal silicon, alumina, zinc oxide, magnesium oxide, aluminum oxide, silicon dioxide, cerium oxide, iron oxide, aluminum hydroxide, cerium hydroxide, aluminum nitride, boron nitride, silicon carbide, diamond, graphite, carbon nanotubes, graphene, etc. These can be used alone or in appropriate combination of two or more, and it is preferable to use a combination of a large particle component and a small particle component.

If the average particle size of the large particle component is less than 0.1 μm, the viscosity of the resulting composition may become too high and the extensibility may become poor, whereas if it is more than 100 μm, the resulting composition may become non-uniform. Therefore, the average particle size of the large particle component is preferably in the range of 0.1 to 100 μm, preferably in the range of 10 to 50 μm, and more preferably in the range of 10 to 45 μm.
Furthermore, if the average particle size of the small particle component is less than 0.01 μm, the viscosity of the resulting composition may become too high and the extensibility may become poor, whereas if it is 10 μm or more, the resulting composition may become non-uniform. Therefore, the average particle size of the small particle component is preferably in the range of 0.01 μm or more and less than 10 μm, and more preferably in the range of 0.1 to 4 μm.
The ratio of the large particle component to the small particle component is not particularly limited, but is preferably in the range of 9:1 to 1:9 (mass ratio). The shapes of the large particle component and the small particle component are not particularly limited and may be spherical, irregular, acicular, etc.
The average particle size can be determined, for example, as a volume-based average value (or median diameter) in particle size distribution measurement by laser light diffraction method.

The amount of component (C) is 10 to 95% by mass of the entire composition, preferably 20 to 90% by mass, more preferably 30 to 88% by mass, and most preferably 50 to 85% by mass. If it is more than 95% by mass, the composition will have poor extensibility, and if it is less than 10% by mass, the composition will have poor thermal conductivity.

Component (D) Component (D) is an organohydrogenpolysiloxane having, in each molecule, at least 2 hydrogen atoms bonded to silicon atoms (SiH groups), preferably 2 to 100, and more preferably 2 to 20. The organohydrogenpolysiloxane may be any organohydrogenpolysiloxane in which the SiH groups in the molecule can undergo an addition reaction with the aliphatic unsaturated hydrocarbon groups in components (A) and (B) described above in the presence of a platinum group metal catalyst to form a crosslinked structure.

The molecular structure of the organohydrogenpolysiloxane is not particularly limited as long as it has the above properties, and examples of such structures include a linear structure, a branched structure, a cyclic structure, and a linear structure having a partially branched or cyclic structure. A linear structure or a cyclic structure is preferred.

The organohydrogenpolysiloxane preferably has a kinetic viscosity at 25° C. of 1 to 1,000 mm ² /s, and more preferably 10 to 100 mm ² /s. If the kinetic viscosity is 1 mm ² /s or more, there is no risk of the physical properties of the silicone composition being reduced, and if it is 1,000 mm ² /s or less, there is no risk of the silicone composition having poor extensibility.

The organic group bonded to the silicon atom of the organohydrogenpolysiloxane may be an unsubstituted or substituted monovalent hydrocarbon group other than an aliphatic unsaturated hydrocarbon group. In particular, it is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms. For example, alkyl groups such as methyl, ethyl, propyl, butyl, hexyl, and dodecyl groups, aryl groups such as phenyl groups, aralkyl groups such as 2-phenylethyl and 2-phenylpropyl groups, and groups in which some or all of the hydrogen atoms of these groups have been substituted with halogen atoms such as fluorine, bromine, and chlorine, cyano groups, and epoxy ring-containing organic groups (glycidyl groups or glycidyloxy group-substituted alkyl groups), such as chloromethyl groups, chloropropyl groups, bromoethyl groups, trifluoropropyl groups, cyanoethyl groups, 2-glycidoxyethyl groups, 3-glycidoxypropyl groups, and 4-glycidoxybutyl groups. Among these, methyl groups and 3-glycidoxypropyl groups are preferred.

The organohydrogenpolysiloxane may be used alone or in a mixture of two or more types.

The amount of organohydrogenpolysiloxane in component (D) is such that the number of SiH groups in component (D) relative to the total number of aliphatic unsaturated hydrocarbon groups in components (A) and (B) is 0.5 to 5, preferably 0.7 to 4.5, and more preferably 1 to 4. If the amount of component (D) is less than the lower limit above, the addition reaction will not proceed sufficiently, resulting in insufficient crosslinking. If the amount exceeds the upper limit above, the crosslinked structure may become non-uniform and the shelf life of the composition may be significantly reduced.

In the present invention, it is desirable that the number of SiH groups in the composition (particularly in component (D)) relative to the total number of aliphatic unsaturated hydrocarbon groups in the composition (particularly in components (A), (B), (E), and the optional components (I), (J), and (K) described below) is 0.5 to 5, and particularly 1 to 4.

（式中、Ｒ¹は置換基を有していてもよい炭素数１～１０の１価炭化水素基を表し、それぞれのＲ¹は同一であっても異なっていてもよい。Ｒ²はそれぞれ独立に非置換もしくは置換の炭素数１～２０のアルキル基、非置換もしくは置換の炭素数６～１０のアリール基、炭素数７～１０のアラルキル基、非置換もしくは置換の炭素数２～１０のアルケニル基、又は非置換もしくは置換の炭素数１～２０のアルコキシ基であり、Ｒ³は非置換もしくは置換の炭素数１～１０のアルキル基、又は非置換もしくは置換の炭素数６～１０のアリール基であり、ｎは１～３の整数であり、ｍは１～１２の整数である。） Component (E) Component (E) is a hydrolyzable organosilane compound represented by the following general formula (1) which has both a hydrolyzable silyl group and an S-Si bond in one molecule. It may use either a single compound or an appropriate combination of two or more compounds, and it acts as an adhesion aid for improving the adhesion of the silicone composition obtained in the present invention to a surface onto which a precious metal such as gold has been vapor-deposited.

(In the formula, R ¹ represents a monovalent hydrocarbon group having 1 to 10 carbon atoms which may have a substituent, and each R ¹ may be the same or different. Each R ² is independently an unsubstituted or substituted alkyl group having 1 to 20 carbon atoms, an unsubstituted or substituted aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 10 carbon atoms, an unsubstituted or substituted alkenyl group having 2 to 10 carbon atoms, or an unsubstituted or substituted alkoxy group having 1 to 20 carbon atoms; R ³ represents an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms, or an unsubstituted or substituted aryl group having 6 to 10 carbon atoms; n is an integer from 1 to 3; and m is an integer from 1 to 12.)

R ¹ in the above formula (1) is a monovalent hydrocarbon group having 1 to 10 carbon atoms which may have a substituent, and is preferably a monovalent saturated aliphatic hydrocarbon group which may have a substituent, a monovalent unsaturated aliphatic hydrocarbon group which may have a substituent, or a monovalent aromatic hydrocarbon group (including an aromatic heterocycle) which may have a substituent, more preferably a monovalent saturated aliphatic hydrocarbon group which may have a substituent, or a monovalent aromatic hydrocarbon group which may have a substituent, and particularly preferably a monovalent saturated aliphatic hydrocarbon group which may have a substituent.
Specific examples of monovalent saturated aliphatic hydrocarbon groups which may have a substituent include linear alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl and octyl groups; branched alkyl groups such as isopropyl, isobutyl, tert-butyl, isopentyl and neopentyl groups; cycloalkyl groups such as cyclopentyl, cyclohexyl and cycloheptyl groups; and halogen-substituted alkyl groups such as chloromethyl, 3-chloropropyl, 3,3,3-trifluoropropyl and bromopropyl groups, each of which has 1 to 10 carbon atoms, preferably 1 to 8 carbon atoms, and more preferably 1 to 6 carbon atoms.
Specific examples of monovalent unsaturated aliphatic hydrocarbon groups which may have a substituent include alkenyl groups such as ethenyl, 1-methylethenyl, and 2-propenyl, and alkynyl groups such as ethynyl and 2-propynyl, each of which has 2 to 10 carbon atoms, preferably 2 to 8 carbon atoms, and more preferably 2 to 6 carbon atoms.
Specific examples of monovalent aromatic hydrocarbon groups which may have a substituent include aryl groups such as a phenyl group or a tolyl group, aralkyl groups such as a benzyl group or a 2-phenylethyl group, and halogen-substituted aryl groups such as an α,α,α-trifluorotolyl group or a chlorobenzyl group, each of which has 6 to 10 carbon atoms, preferably 6 to 8 carbon atoms, and more preferably 6 carbon atoms.
As R ¹ in the above formula (1), a methyl group, an ethyl group, a propyl group, a butyl group, a phenyl group, etc. are preferable, and among these, a methyl group and an ethyl group are more preferable.

R ² is independently an unsubstituted or substituted alkyl group having 1 to 20 carbon atoms, an unsubstituted or substituted aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 10 carbon atoms, an unsubstituted or substituted alkenyl group having 2 to 10 carbon atoms, or an unsubstituted or substituted alkoxy group having 1 to 20 carbon atoms. Examples of the alkyl group of R ² include a methyl group, an ethyl group, a tert-butyl group, an octyl group, a decyl group, and a dodecyl group. Examples of the aryl group include a phenyl group, a tolyl group, and a xylyl group. Examples of the aralkyl group include a benzyl group. Examples of the alkenyl group include a vinyl group, a propenyl group, and a pentenyl group. Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, an octoxy group, and a dodecoxy group. Examples of the substituent in the substituted alkyl group, substituted aryl group, substituted alkenyl group, and substituted alkoxy group include a halogen atom. Of these, ^R2 is preferably a methyl group, an ethyl group, a methoxy group, or an ethoxy group, and more preferably at least one of R2 is a methoxy group or an ethoxy group.

^R3 is an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms, or an unsubstituted or substituted aryl group having 6 to 10 carbon atoms, and examples of the alkyl group of ^R3 include a methyl group, an ethyl group, a propyl group, and a butyl group, examples of the aryl group include a phenyl group, and examples of the substituent in the substituted alkyl group or substituted aryl group include a halogen atom. Of these, a methyl group is preferable as ^R3 .

Furthermore, n is an integer from 1 to 3, and preferably 3. m is an integer from 1 to 12, and preferably an integer from 1 to 8.

（式中、Ｒ¹、ｎ、Ｒ²は上記と同様であり、Ｒ⁸は非置換もしくは置換の炭素数１～２０のアルキル基、非置換もしくは置換の炭素数６～１０のアリール基、炭素数７～１０のアラルキル基、又は非置換もしくは置換の炭素数２～１０のアルケニル基であり、Ｍｅはメチル基である。） The hydrolyzable organosilane compound represented by formula (1) is preferably one represented by the following general formula (5).

(In the formula, R ¹ , n, and R ² are the same as above, R ⁸ is an unsubstituted or substituted alkyl group having 1 to 20 carbon atoms, an unsubstituted or substituted aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 10 carbon atoms, or an unsubstituted or substituted alkenyl group having 2 to 10 carbon atoms, and Me is a methyl group.)

R ⁸ in the above formula (5) is an unsubstituted or substituted alkyl group having 1 to 20 carbon atoms, an unsubstituted or substituted aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 10 carbon atoms, or an unsubstituted or substituted alkenyl group having 2 to 10 carbon atoms, and examples of the alkyl group of R ⁸ include a methyl group, an ethyl group, a tert-butyl group, an octyl group, a decyl group, and a dodecyl group, examples of the aryl group include a phenyl group, a tolyl group, and a xylyl group, examples of the aralkyl group include a benzyl group, examples of the alkenyl group include a vinyl group, a propenyl group, and a pentenyl group, and examples of the substituent in the substituted alkyl group, substituted aryl group, and substituted alkenyl group include a halogen atom. Among these, a methyl group and an ethyl group are preferable as R ⁸ .

（式中、Ｒ¹、ｎ、Ｍｅは上記と同様であり、Ｅｔはエチル基である。） As the hydrolyzable organosilane compound of component (E), those represented by the following general formulas (6) to (11) are more preferable, and one or more of these can be used.

(In the formula, R ¹ , n, and Me are the same as above, and Et is an ethyl group.)

The amount of component (E) is 0.1 to 10 parts by mass, preferably 0.2 to 7 parts by mass, per 100 parts by mass of the total of components (A) and (B). If the amount is less than 0.1 part by mass, it will not be effective in improving the adhesion of the silicone composition to surfaces onto which precious metals such as gold have been vapor-deposited, whereas if the amount is more than 10 parts by mass, it may inhibit the addition reaction of the silicone composition, thereby reducing the adhesion to surfaces onto which precious metals such as gold have been vapor-deposited.

Component (F) Component (F) is a platinum group metal catalyst, and functions to promote the addition reaction of the above-mentioned components. The platinum group metal catalyst may be any of those conventionally known for use in addition reactions. Examples include platinum-based, palladium-based, and rhodium-based catalysts, among which platinum or platinum compounds, which are relatively easy to obtain, are preferred. Examples include simple platinum, platinum black, chloroplatinic acid, platinum-olefin complexes, platinum-alcohol complexes, platinum coordination compounds, and the like. The platinum group metal catalyst may be used alone or in combination of two or more.

The amount of component (F) to be blended should be an effective amount as a catalyst, that is, an effective amount required to promote the addition reaction and cure the addition-curable silicone composition of the present invention. Preferably, the amount is 0.1 to 500 ppm, more preferably 1 to 200 ppm, based on the total mass of components (A) and (B) converted into platinum group metal atoms. If the amount of catalyst is less than the lower limit, the catalytic effect may not be obtained. Furthermore, exceeding the upper limit is not preferable because the catalytic effect does not increase and it is uneconomical.

In addition to the above components, the addition-curable silicone composition of the present invention may further contain the following optional components as necessary.

Component (G) Component (G) is a reaction inhibitor that suppresses the progress of the hydrosilylation reaction at room temperature, and can be added to extend shelf life and pot life. The reaction inhibitor can be any reaction inhibitor known in the art that is used in addition curing silicone compositions. Examples of such reaction inhibitors include acetylene compounds such as acetylene alcohols (e.g., ethynylmethyldecylcarbinol, 1-ethynyl-1-cyclohexanol, 3,5-dimethyl-1-hexyn-3-ol), various nitrogen compounds such as tributylamine, tetramethylethylenediamine, and benzotriazole, organic phosphorus compounds such as triphenylphosphine, oxime compounds, and organic chloro compounds.

When component (G) is blended, the blending amount is preferably 0.05 to 5 parts by mass, and more preferably 0.1 to 1 part by mass, per 100 parts by mass of the combined total of components (A) and (B). If the amount of reaction inhibitor is less than 0.05 parts by mass, it may not be possible to obtain the desired sufficient shelf life and pot life, and if it is more than 5 parts by mass, the curability of the silicone composition may decrease.
The reaction inhibitor may be diluted with organo(poly)siloxane, toluene, or the like to improve dispersibility in the silicone composition.

Component (H) Component (H) is an organic peroxide selected from peroxyketals, hydroperoxides, dialkyl peroxides, diacyl peroxides, peroxy esters, and peroxydicarbonates that decompose under specific conditions to generate free radicals. It may use one type alone or two or more types in appropriate combination, and it acts as a reaction initiator that introduces a silalkylene structure into the siloxane crosslinked structure of the silicone composition obtained by the present invention.

Specifically, peroxyketals such as 1,1-di(tert-butylperoxy)cyclohexane and 2,2-(4,4-di-(tert-butylperoxy)cyclohexyl)propane, hydroperoxides such as p-menthane hydroperoxide and diisopropylbenzene hydroperoxide, dialkyl peroxides such as dicumyl peroxide, tert-butylcumyl peroxide and 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, diacyl peroxides such as dibenzoyl peroxide and disuccinic acid peroxide, peroxyesters such as tert-butyl peroxyacetate and tert-butyl peroxybenzoate, and peroxydicarbonates such as diisopropyl peroxydicarbonate are preferably used. In particular, the use of peroxyketals, hydroperoxides, dialkyl peroxides, and peroxyesters with relatively high decomposition temperatures is preferred from the standpoint of ease of handling and storage.

In particular, the decomposition temperature for obtaining a one-hour half-life is preferably in the range of 50 to 200°C, and more preferably in the range of 80 to 170°C. If the decomposition temperature for obtaining a one-hour half-life is less than 50°C, an explosive reaction may occur, making handling difficult, while if it exceeds 200°C, the reactivity is low, and the efficiency of introducing the silalkylene structure into the structure of the silicone composition may decrease. These organic peroxides may also be used diluted with any organic solvent, hydrocarbon, liquid paraffin, inert solid, etc.

When component (H) is blended, the blending amount is preferably 0.01 to 10 parts by mass, and more preferably 0.1 to 5 parts by mass, per 100 parts by mass of the combined total of components (A) and (B). If the blending amount is less than 0.01 part by mass, the efficiency of introducing the silalkylene structure into the structure of the silicone composition decreases, and if the blending amount exceeds 10 parts by mass, the storage stability of the silicone composition may decrease.

（式中、Ｒ¹は置換基を有していてもよい炭素数１～１０の１価炭化水素基を表し、それぞれのＲ¹は同一であっても異なっていてもよい。Ｒ⁴はエポキシ基、アクリロイル基、メタクリロイル基、アルコキシシリル基から選択される基である。Ｘはヘテロ原子を含んでもよい炭素数１～２０のアルキレン基である。ａは０～２の整数である。） Component (I) Component (I) represented by general formula (2) below is a hydrolyzable organosilane compound which may be used alone or in appropriate combination of two or more types and which acts as an adhesion aid to improve the adhesiveness of the silicone composition obtained in the present invention.

(In the formula, ^R1 represents a monovalent hydrocarbon group having 1 to 10 carbon atoms which may have a substituent, and each ^R1 may be the same or different. ^R4 represents a group selected from an epoxy group, an acryloyl group, a methacryloyl group, and an alkoxysilyl group. X represents an alkylene group having 1 to 20 carbon atoms which may contain a heteroatom. a represents an integer of 0 to 2.)

R ¹ in the above formula (2) is the same as described above, and among them, a methyl group, an ethyl group, a 3,3,3-trifluoropropyl group, and a phenyl group are preferable, a methyl group, an ethyl group, and a phenyl group are more preferable, and a methyl group is particularly preferable.

^R4 is a group selected from an epoxy group, an acryloyl group, a methacryloyl group, and an alkoxysilyl group. For the purpose of improving adhesion to metal adherends such as semiconductor chips and heat spreaders in semiconductor devices, it is preferable to select an epoxy group or an alkoxysilyl group.
Examples of the alkoxysilyl group include a trimethoxy group, a dimethoxymethyl group, a methoxydimethylsilyl group, a triethoxy group, a diethoxymethyl group, and an ethoxydimethylsilyl group. Of these, a trimethoxy group and a triethoxy group are preferred.

X is an alkylene group having 1 to 20 carbon atoms which may contain a heteroatom, and is a spacer connecting ^R4 and the silicon atom. The structure of X is not particularly limited, and may be linear or branched, but is preferably linear. Specific examples of X include the following:
_{-CH2OCH2CH2CH2- ​ ​ ​
-CH2OCH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2- ​ ​ ​ ​ ​ ​ ​ ​}
-( _CH2 ) _x-
(x is an integer from 1 to 20.)

a is an integer from 0 to 2, and specifies the number of alkoxy groups in the alkoxysilyl group of the hydrolyzable organosilane compound of component (I). The greater the number of alkoxysilyl groups in component (I), the easier it is for component (I) to be immobilized on the surface of the thermally conductive filler of component (C), so a is preferably 0 or 1, and more preferably 0.

When component (I) is blended, the blending amount is 0.1 to 30 parts by mass, preferably 1 to 20 parts by mass, per 100 parts by mass of the total of components (A) and (B). If the blending amount is less than 0.1 part by mass, the amount of coverage on the thermally conductive filler surface will decrease, and there is a risk that adhesiveness will not be fully expressed. If the blending amount exceeds 30 parts by mass, the strength of the cured product of the silicone composition will decrease, and there is a risk that adhesiveness will not be fully expressed, which is not preferable.

（式中、Ｒ¹は置換基を有していてもよい炭素数１～１０の１価炭化水素基を表し、それぞれのＲ¹は同一であっても異なっていてもよい。ｂは５～１００の整数である。） Component (J) The addition-curable silicone composition of the present invention can further contain a hydrolyzable organopolysiloxane compound (J) represented by the following general formula (3): The hydrolyzable organopolysiloxane compound of component (J) is used to treat the surface of the thermally conductive filler, and plays a role in assisting in high loading of the filler.

(In the formula, R ¹ represents a monovalent hydrocarbon group having 1 to 10 carbon atoms which may have a substituent, and each R ¹ may be the same or different, and b is an integer of 5 to 100.)

R ¹ in the above formula (3) is the same as described above, and is particularly preferably a methyl group. b is an integer from 5 to 100, and preferably an integer from 10 to 60. If the value of b is less than 5, oil bleeding from the silicone composition may become severe, and reliability may be reduced. If the value of b is greater than 100, wettability with the filler may be insufficient.

When component (J) is blended, the blending amount is preferably 1 to 200 parts by mass, and particularly preferably 5 to 30 parts by mass, per 100 parts by mass of the combined total of components (A) and (B). If the amount of component (J) is less than 1 part by mass, sufficient wettability may not be exhibited. Furthermore, if the amount of component (J) is more than 200 parts by mass, oil bleeding from the composition may become severe.

（式中、Ｒ¹は置換基を有していてもよい炭素数１～１０の１価炭化水素基を表し、それぞれのＲ¹は同一であっても異なっていてもよい。Ｒ⁵は炭素数２～６のアルケニル基である。ｐ、ｑは１≦ｐ≦５０、１≦ｑ≦９９、５≦ｐ＋ｑ≦１００を満足する数である。） Component (K) The addition-curable silicone composition of the present invention can further contain a hydrolyzable organopolysiloxane compound (K) represented by the following general formula (4): The hydrolyzable organopolysiloxane compound of component (K) treats the surface of the thermally conductive filler and also has a reinforcing effect that increases the strength of the silicone composition.

(In the formula, ^R1 represents a monovalent hydrocarbon group having 1 to 10 carbon atoms which may have a substituent, and each ^R1 may be the same or different. ^R5 represents an alkenyl group having 2 to 6 carbon atoms. p and q are numbers which satisfy 1≦p≦50, 1≦q≦99, and 5≦p+q≦100.)

In the above formula (4), ^R1 is the same as described above, and is particularly preferably a methyl group. ^R5 is an alkenyl group having 2 to 6 carbon atoms, specifically, vinyl group, allyl group, propenyl group, isopropenyl group, butenyl group, hexenyl group, cyclohexenyl group, etc., and is particularly preferably a vinyl group.

p is 1 to 50, preferably 1 to 10, and q is 1 to 99, preferably 4 to 50. If p is small, the silicone composition may not have a sufficient reinforcing effect, if p is large, the crosslinking may be uneven, if q is small, oil bleeding may be severe, and if q is large, the treatment of the thermally conductive filler surface may be insufficient. Also, p + q is 5 ≦ p + q ≦ 100, but preferably 5 ≦ p + q ≦ 60. If p + q is less than 5, the composition may suffer from severe oil bleeding and may become less reliable. Also, if p + q is greater than 100, the wettability with the filler may be insufficient.

When component (K) is blended, the blending amount is 1 to 50 parts by mass, and preferably 2 to 30 parts by mass, per 100 parts by mass of the total of components (A) and (B). If the amount of component (K) is less than the above lower limit, sufficient wettability and reinforcing effect may not be exhibited. Furthermore, if the amount of component (K) is more than the above upper limit, oil bleeding from the composition may become severe.

Other Components The addition-curable silicone composition of the present invention may contain a non-reactive organo(poly)siloxane such as methylpolysiloxane in order to adjust the strength and viscosity of the composition. Furthermore, in order to prevent deterioration of the silicone composition, a conventionally known antioxidant such as 2,6-di-tert-butyl-4-methylphenol may be contained as necessary. Furthermore, dyes, pigments, flame retardants, anti-settling agents, thixotropy improvers, etc. may be blended as necessary.

Step of preparing the silicone composition The method of preparing the silicone composition of the present invention will now be described. The method of preparing the silicone composition of the present invention is not particularly limited, but includes the steps of preparing a silicone composition containing the above-mentioned components (A) to (F) and, if necessary, components (G) to (K).

Methods include mixing the above-mentioned components (A) to (F), and, if necessary, components (G) to (K), using a mixer such as Trimix, Twinmix, or Planetary Mixer (all registered trademarks of mixers manufactured by Inoue Seisakusho Co., Ltd.), Ultra Mixer (registered trademark of mixers manufactured by Mizuho Kogyo Co., Ltd.), or Hivis Dispermix (registered trademark of mixers manufactured by Tokushu Kika Kogyo Co., Ltd.).

The addition-curable silicone composition of the present invention may be mixed while being heated. There are no particular limitations on the heating conditions, but the temperature is usually 25 to 220°C, preferably 40 to 200°C, and particularly preferably 50 to 200°C, and the heating time is usually 3 minutes to 24 hours, preferably 5 minutes to 12 hours, and particularly preferably 10 minutes to 6 hours. Degassing may also be performed during heating.
In the present invention, from the viewpoint of enabling the silicone composition to exhibit good adhesive strength, it is preferable to first heat-mix components (A) to (C) at 50 to 200° C., and then mix components (D) to (F). When optional components (G) to (K) are added, it is preferable to first heat-mix components (A) to (C) and (I) to (K) at 50 to 200° C., and then mix components (D) to (H).

The addition-curable silicone composition of the present invention preferably has a viscosity measured at 25°C of 1 to 1,000 Pa·s, more preferably 20 to 700 Pa·s, and even more preferably 40 to 600 Pa·s. If the viscosity is less than 1 Pa·s, there is a risk of poor workability, such as difficulty in maintaining the shape. Also, if the viscosity exceeds 1,000 Pa·s, there is a risk of poor workability, such as difficulty in discharging or applying. The above-mentioned viscosity can be obtained by adjusting the blending amounts of each of the above-mentioned components.
Furthermore, the addition-curable silicone composition of the present invention is thermally conductive, and typically has a thermal conductivity of 0.5 to 10 W/m·K.
In the present invention, the viscosity is a value measured at 25° C. using a rotational viscometer, and the thermal conductivity is a value measured by a hot disk method.

The addition-curable silicone composition of the present invention can be suitably used as a composition for dissipating heat by being interposed between an electronic component such as an LSI or other heat-generating component and a cooling component, and for transferring heat from the heat-generating component to the cooling component, and can be used in the same manner as conventional silicone heat-dissipating greases. For example, the addition-curable silicone composition of the present invention can be cured by heat generated by a heat-generating component such as an electronic component, or the addition-curable silicone composition of the present invention may be actively heated and cured after being applied.
The addition-curable silicone composition of the present invention has particularly good adhesion to surfaces on which precious metals such as gold have been vapor-deposited, and is therefore particularly suitable for use as a thermal grease for semiconductor devices in which precious metals such as gold have been vapor-deposited onto the surfaces of semiconductor chips or heat spreaders for the purpose of improving reliability.
This makes it possible to provide a semiconductor device in which a cured product of the addition-curable silicone composition of the present invention is interposed between a heat-generating component and a cooling component.

The curing conditions when the addition-curable silicone composition of the present invention is heat-cured are not particularly limited, but are usually 80 to 200°C, preferably 100 to 180°C, for 30 minutes to 4 hours, preferably 30 minutes to 2 hours.

The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples. The kinematic viscosity is the value at 25° C. measured with an Ubbelohde-type Ostwald viscometer.
First, the following components for preparing the addition-curable silicone composition of the present invention were prepared.

(A) Component A-1: Dimethylpolysiloxane having both ends capped with dimethylvinylsilyl groups and a kinetic viscosity at 25° C. of 600 mm ² /s: SiVi group amount 0.00014 mol/g

(B) Component B-1: Silicone resin represented by the following average composition formula: kinetic viscosity of 3.0 mm ² /s when made into a 50% by weight solution in xylene solvent, SiVi group amount of 0.0004 mol/g
(SiO4 _/ 2) _1.0 (( _CH2 =CH) _{( CH3} )2SiO1 _/ 2) _0.12 (( _CH3 )3SiO1 _{/2 ) 0.75}

(C) Component C-1: Aluminum powder obtained by premixing aluminum powder having an average particle size of 20.0 μm and aluminum powder having an average particle size of 2.0 μm in a mass ratio of 60:40 C-2: Zinc oxide powder having an average particle size of 1.0 μm

Ｄ－２：下記式（１３）で示されるポリシロキサン
（２５℃における動粘度＝２５ｍｍ²／ｓ）

Ｄ－３：下記式（１４）で示されるポリシロキサン
（２５℃における動粘度＝１１ｍｍ²／ｓ）

(D) Component D-1: Methylhydrogendimethylpolysiloxane represented by the following formula (12) (kinematic viscosity at 25° C.=12 mm ² /s)

D-2: Polysiloxane represented by the following formula (13) (kinematic viscosity at 25° C.=25 mm ² /s)

D-3: Polysiloxane represented by the following formula (14) (kinematic viscosity at 25° C.=11 mm ² /s)

（式中、Ｍｅはメチル基。）
Ｅ－２：下記式（１６）で示される加水分解性オルガノシラン化合物

（式中、Ｍｅはメチル基、Ｅｔはエチル基。）
Ｅ－３：下記式（１７）で示される加水分解性オルガノシラン化合物

（式中、Ｍｅはメチル基。） (E) Component E-1: a hydrolyzable organosilane compound represented by the following formula (15):

(In the formula, Me is a methyl group.)
E-2: A hydrolyzable organosilane compound represented by the following formula (16):

(In the formula, Me is a methyl group, and Et is an ethyl group.)
E-3: A hydrolyzable organosilane compound represented by the following formula (17):

(In the formula, Me is a methyl group.)

(F) Component F-1: A solution of platinum-divinyltetramethyldisiloxane complex dissolved in the same dimethylpolysiloxane as A-1 (platinum atom content: 1% by mass)

(G) Component G-1: 1-ethynyl-1-cyclohexanol represented by the following formula (18):

Ｈ－２：下記式（２０）で示される１，１－ジ（ｔｅｒｔ－ブチルパーオキシ）シクロヘキサン（１時間半減期を得るための分解温度＝１１１℃）

(H) Component H-1: 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane represented by the following formula (19) (decomposition temperature for obtaining a half-life of 1 hour = 138°C)

H-2: 1,1-di(tert-butylperoxy)cyclohexane represented by the following formula (20) (decomposition temperature for obtaining a half-life of 1 hour = 111°C)

Ｉ－２：下記式（２２）で示される８－グリシドキシオクチルトリメトキシシラン

(I) Component I-1: 3-glycidoxypropyltrimethoxysilane represented by the following formula (21)

I-2: 8-glycidoxyoctyltrimethoxysilane represented by the following formula (22):

(J) Component J-1: a dimethylpolysiloxane having one end blocked with a trimethoxysilyl group, represented by the following formula (23):

(K) Component K-1: a methylvinylpolysiloxane capped at both ends with trimethoxysilyl groups, represented by the following formula (24):

[Examples 1 to 11, Example 4 is a reference example, Comparative Examples 1 to 7]
Preparation of Silicone Composition
The above components (A) to (K) were blended in the amounts shown in Tables 1 to 3 by the method shown below to prepare silicone compositions. In the tables, the mass of component (F) is the mass of a solution (platinum atom content: 1 mass%) in which a platinum-divinyltetramethyldisiloxane complex is dissolved in dimethylpolysiloxane. SiH/SiVi is the ratio of the total number of SiH groups in component (D) to the total number of alkenyl groups in components (A), (B), and (K). SiH(D)/SiVi((A)+(B)) is the number of SiH groups in component (D) to the total number of aliphatic unsaturated hydrocarbon groups in components (A) and (B).

Components (A), (B), (C), (J) and (K) were added to a 5 liter planetary mixer (Inoue Seisakusho Co., Ltd.) and mixed at 170°C for 1 hour. The mixture was cooled to below 40°C, then component (I) was added and mixed at 70°C for 1 hour. The mixture was cooled to below 40°C, then components (G), (F), (D), (H) and (E) were added and mixed until uniform to prepare a silicone composition.

The viscosity, thermal conductivity, and adhesive strength of each silicone composition obtained by the above method were measured according to the following methods. The results are shown in Tables 1 to 3.

[viscosity]
The absolute viscosity of each silicone composition was measured at 25° C. using a Malcolm viscometer (Type PC-1T) (Rotor A, 10 rpm, shear rate 6 [1/s]).

[Thermal conductivity]
Each silicone composition was wrapped in kitchen wrap, and the thermal conductivity was measured using a Kyoto Electronics Manufacturing Co., Ltd. TPS-2500S.

[Adhesive strength]
Each silicone composition was sandwiched between a 10 mm x 10 mm silicon wafer and a 20 mm x 20 mm gold-deposited silicon wafer (gold layer thickness = 200 μm), and heat-cured for 60 minutes at 150 ° C. while applying a pressure of 1.8 kgf with a clip. Thereafter, the shear adhesive strength was measured using a Dage series-4000PXY (manufactured by Dage Deutchland GmbH).

From the results in Tables 1 to 3, it can be seen that the silicone compositions of Examples 1 to 11, which satisfy the requirements of the present invention, have high adhesive strength to a gold-vapor-deposited surface. In other words, it can be judged that they have excellent adhesive properties. On the other hand, the silicone compositions of Comparative Examples 1 to 7 have low adhesive strength to a gold-vapor-deposited surface, or the adhesive strength cannot be measured. In other words, it can be judged that they have poor adhesive properties.
Therefore, the addition-curable silicone composition of the present invention has good adhesion to surfaces on which a precious metal such as gold has been vapor-deposited. Because of these characteristics, the addition-curable silicone composition of the present invention can be particularly suitably used as a thermal grease for semiconductor devices in which a precious metal such as gold has been vapor-deposited on the surfaces of semiconductor chips or heat spreaders for the purpose of improving reliability.

The present invention is not limited to the above-described embodiments. The above-described embodiments are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and exhibits similar effects is included within the technical scope of the present invention.

Claims (8)

(A) an organopolysiloxane having at least two aliphatic unsaturated hydrocarbon groups in one molecule and having a kinetic viscosity at 25° C. of 60 to 100,000 mm ² /s: 100 parts by mass,
(B) A silicone resin having at least one aliphatic unsaturated hydrocarbon group in one molecule, and including SiO4 _{/2 units} , ^R62R7SiO1 _/2 ^units , and ^R63SiO1 _{/2 units} (wherein ^R6 is each independently a monovalent hydrocarbon group having no aliphatic unsaturated bonds, and ^R7 is a monovalent aliphatic unsaturated hydrocarbon group), and
A silicone resin in which the molar ratio [(M units)/(Q units)] of the SiO _4/2 units (Q units) to the R ⁶ ₂ R ⁷ SiO _1/2 units and R ⁶ ₃ SiO _1/2 units (M units) is a number that satisfies 0.1 to 3: 3 to 50 parts by mass per 100 parts by mass of component (A),
(C) at least one thermally conductive filler selected from the group consisting of metals, metal oxides, metal hydroxides, metal nitrides, metal carbides, and allotropes of carbon: an amount of 50 to 95.0 mass% based on the total mass of the composition;
(D) an organohydrogenpolysiloxane having two or more hydrogen atoms bonded to silicon atoms per molecule, comprising one or more organohydrogenpolysiloxanes having an epoxy ring-containing organic group and one or more other organohydrogenpolysiloxanes: an amount such that the number of SiH groups relative to the total number of aliphatic unsaturated hydrocarbon groups in components (A) and (B) is 0.7 to 5,
(E) a hydrolyzable organosilane compound represented by the following general formula (1): 0.1 to 10 parts by mass per 100 parts by mass of the total of the components (A) and (B),

(In the formula, R ¹ represents a monovalent hydrocarbon group having 1 to 10 carbon atoms which may have a substituent, and each R ¹ may be the same or different. Each R ² is independently an unsubstituted or substituted alkyl group having 1 to 20 carbon atoms, an unsubstituted or substituted aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 10 carbon atoms, an unsubstituted or substituted alkenyl group having 2 to 10 carbon atoms, or an unsubstituted or substituted alkoxy group having 1 to 20 carbon atoms; R ³ represents an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms, or an unsubstituted or substituted aryl group having 6 to 10 carbon atoms; n is an integer from 1 to 3; and m is an integer from 1 to 12.)
(F) a platinum group metal catalyst: an effective amount,
(H) 0.01 to 10 parts by mass of an organic peroxide selected from peroxyketals, hydroperoxides, dialkyl peroxides, diacyl peroxides, peroxy esters, and peroxydicarbonates, per 100 parts by mass of the total of components (A) and (B), and (I) 0.1 to 30 parts by mass of a hydrolyzable organosilane compound represented by the following general formula (2):

(In the formula, ^R1 represents a monovalent hydrocarbon group having 1 to 10 carbon atoms which may have a substituent, and each ^R1 may be the same or different. ^R4 represents a group selected from an epoxy group, an acryloyl group, a methacryloyl group, and an alkoxysilyl group. X represents an alkylene group having 1 to 20 carbon atoms which may contain a heteroatom other than a sulfur atom. a represents an integer of 0 to 2.)
An addition-curable silicone composition comprising, as an essential component: The addition-curable silicone composition according to claim 1 further comprises 0.05 to 5 parts by mass of a reaction inhibitor (G) per 100 parts by mass of the total of components (A) and (B). 3. The addition-curable silicone composition according to claim 1 or 2, further comprising (J) 1 to 200 parts by mass of a hydrolyzable organopolysiloxane compound represented by the following general formula (3), per 100 parts by mass of the total of the components (A) and (B):

(In the formula, R ¹ represents a monovalent hydrocarbon group having 1 to 10 carbon atoms which may have a substituent, and each R ¹ may be the same or different, and b is an integer of 5 to 100.) The addition-curable silicone composition according to any one of claims 1 to 3, further comprising (K) 1 to 50 parts by mass of a hydrolyzable organopolysiloxane compound represented by the following general formula (4), per 100 parts by mass of the total of the components (A) and (B):

(In the formula, ^R1 represents a monovalent hydrocarbon group having 1 to 10 carbon atoms which may have a substituent, and each ^R1 may be the same or different. ^R5 represents an alkenyl group having 2 to 6 carbon atoms. p and q are numbers which satisfy 1≦p≦50, 1≦q≦99, and 5≦p+q≦100.) The addition-curable silicone composition according to any one of claims 1 to 4, wherein component (C) is a combination of a large particle component having an average particle size of 10 to 100 μm and a small particle component having an average particle size of 0.01 μm or more and less than 10 μm. The addition-curable silicone composition according to claim 5, in which the ratio of large particle components to small particle components is 9:1 to 1:9 (mass ratio). The addition-curable silicone composition according to any one of claims 1 to 6, which is sandwiched between a 10 mm x 10 mm silicon wafer and a 20 mm x 20 mm gold-deposited silicon wafer, and heat-cured at 150°C for 60 minutes while being pressed with a clip of 1.8 kgf, has a shear adhesive strength of 2.4 to 3.5 MPa when measured. A method for producing an addition-curable silicone composition according to any one of claims 1 to 7, comprising heating and mixing components (A) to (C) and (I) in advance at a temperature of 50 to 200°C, and then mixing components (D) to (F) and (H).