JP5832983B2 - Silicone composition - Google Patents

Description

  The present invention relates to a silicone composition. More specifically, the present invention relates to a silicone composition that provides a high thermal conductivity silicone grease, and relates to a silicone composition that can provide a grease having good adhesiveness even when a large amount of a thermal conductive filler is contained.

  Electronic parts such as LSIs and IC chips are widely known to generate heat during use and to deteriorate performance, and various heat dissipation techniques are used as means for solving this. As a general method, a cooling member is disposed in the vicinity of the heat generating portion, and after heat-radiating by efficiently removing heat from the cooling member after bringing them into close contact with each other.

  At this time, if there is a gap between the heat generating member and the cooling member, the heat conductivity is lowered due to the presence of air having poor heat conductivity, and the temperature of the heat generating member cannot be sufficiently lowered. In order to prevent such a phenomenon, for the purpose of preventing air from intervening, a heat radiating material having good thermal conductivity and following the surface of the member, for example, a heat radiating grease or a heat radiating sheet is used (Patent Document 1). To 11). For example, Patent Document 9 describes a thermally conductive silicone grease composition comprising an organopolysiloxane having a specific structure, an alkoxysilane having a specific substituent, and a thermally conductive filler. It describes that the composition has good thermal conductivity, good fluidity, and excellent workability. Patent Document 10 and Patent Document 11 relate to a sheet having adhesiveness and thermal conductivity, and an addition-curing silicone rubber composition having a silicone resin having no thermal conductive filler and no aliphatic unsaturated hydrocarbon group. The heat conductive composition which mix | blended is described. Patent Document 10 and Patent Document 11 describe that the composition provides a thermally conductive cured product having moderate adhesiveness and good thermal conductivity in a thin film state.

  Among heat dissipating greases, there is one that imparts adhesive performance to the grease in order to firmly bond the semiconductor chip and the heat spreader. If the semiconductor chip and heat spreader are not sufficiently bonded via grease, the heat dissipation performance will not be fully exerted and the performance will be significantly reduced. is important. However, in order to improve the thermal conductivity of the heat dissipating grease, it is necessary to fill the heat conductive filler in a large amount. When a large amount of the thermally conductive filler is filled in the grease, there is a problem that the adhesiveness of the obtained cured product is lowered. When the adhesiveness is lowered, the cured product cannot follow the distortion of the semiconductor chip due to the heat history of heat generation and cooling, causing peeling, and in the worst case, the semiconductor chip may be damaged.

  Patent Document 12 contains alkenyl group-containing organopolysiloxane, hydrolyzable methylpolysiloxane, thermally conductive filler, organohydrogenpolysiloxane, triazine ring and alkenyl group-containing adhesion aid, and platinum-based catalyst as essential components. A thermally conductive silicone grease composition is described. Patent Document 12 describes that the composition can provide a heat-dissipating grease that has a small increase in hardness when subjected to heat aging at a high temperature after curing and suppresses a decrease in elongation. Patent Document 13 describes a thermally conductive silicone composition containing a peroxide having a 10-hour half-life temperature of 80 ° C. or more and less than 130 ° C. as a curing agent, and the composition includes a group having a noble metal layer such as gold. It describes that a heat dissipating grease that can be easily cured on the surface of the material can be provided.

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. 4933894 JP 2008-260798 A JP 2009-209165 A JP 2012-102283 A JP 2012-96361 A

  In recent years, the amount of heat generated during operation of high-quality semiconductor devices has been increasing. However, the conventional silicone grease has a problem that the thermal conductivity is not sufficient and a problem that the thermal conductivity is high but the adhesiveness is low. The present invention has been made in view of the above circumstances, and provides a silicone composition capable of providing a silicone grease having a high thermal conductivity and good adhesion compared to conventional silicone greases. With the goal.

  As a result of diligent studies to achieve the above object, the present inventors include an aliphatic unsaturated hydrocarbon group-containing organopolysiloxane, a thermally conductive filler, an organohydrogenpolysiloxane, and a platinum group metal catalyst. Heat conduction by adding a silicone resin having an aliphatic unsaturated hydrocarbon group to the silicone composition, and making the heat conductive filler a filler containing aluminum powder and zinc oxide powder in a specific ratio The present inventors have found that a silicone grease having good adhesiveness can be provided even if a large amount of the filler is contained.

That is, the present invention
(A) an organopolysiloxane having at least two aliphatic unsaturated hydrocarbon groups in one molecule and a kinematic viscosity at 25 ° C. of 60 to 100,000 mm ² / s,
(B) Silicone resin having at least one aliphatic unsaturated hydrocarbon group in one molecule: 2 to 50 parts by mass with respect to 100 parts by mass in total of (A) component and (B) component,
(C) Filler containing aluminum powder and zinc oxide powder, and the weight ratio of aluminum powder to the weight of zinc oxide powder is 1 to 10: 500 for a total of 100 parts by mass of component (A) and component (B) ~ 2,000 parts by mass,
(D) Organohydrogenpolysiloxane having two or more hydrogen atoms bonded to silicon atoms (that is, SiH groups) in one molecule: (A) component and aliphatic unsaturated hydrocarbon in component (B) (D) the amount that the number of SiH groups in the component is 0.5-5 with respect to the total number of groups, and (E) a platinum group metal catalyst: a silicone composition containing an effective amount, and the silicone composition To provide grease.

  Since the silicone composition of the present invention can have good adhesiveness even if it contains a large amount of a thermally conductive filler, it provides a silicone grease having high thermal conductivity and good adhesiveness. be able to.

  Hereinafter, the present invention will be described in detail.

Component (A) Component (A) is an organopolysiloxane having at least two aliphatic unsaturated hydrocarbon groups per molecule and 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 2 to 8, more preferably 2 to 6 carbon atoms, and more preferably an alkenyl group having an aliphatic unsaturated bond. . Examples thereof include alkenyl groups such as vinyl group, allyl group, propenyl group, isopropenyl group, butenyl group, hexenyl group, cyclohexenyl group, and octenyl group. Particularly preferred is a vinyl group. The aliphatic unsaturated hydrocarbon group may be bonded to either a silicon atom at the end of the molecular chain or a silicon atom in the middle of the molecular chain, or may be bonded to both. In particular, in order to improve the flexibility of the resulting cured product, it should be bonded only to the silicon atom at the end of the molecular chain.

The organopolysiloxane should have a kinematic viscosity at 25 ° C. of 60 to 100,000 mm ² / s, preferably 600 to 100,000 mm ² / s. If the kinematic viscosity is less than the lower limit, the physical properties of the composition may be lowered, and if it exceeds the upper limit, the extensibility of the composition may be poor. In the present invention, the kinematic viscosity is a value at 25 ° C. measured by an Ubbelohde Ostwald viscometer.

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

The organopolysiloxane has at least two aliphatic unsaturated hydrocarbon groups in one molecule. Preferably, the amount of aliphatic unsaturated hydrocarbon groups is 2.0 × 10 ^{−5 to} 1.0 × 10 ⁻³ mol / g, especially 2.0 × 10 ^{−5 to} 7.7 in the organopolysiloxane. It is good that it is ^0x10 < ^-4 > mol / g. If the amount of the aliphatic unsaturated hydrocarbon group is less than the lower limit, the resulting composition may be poorly extensible, and if it exceeds the upper limit, the physical properties of the composition may be deteriorated. is there. These organopolysiloxanes can be used alone or in combination of two or more.

  The organic group other than the aliphatic unsaturated hydrocarbon group bonded to the silicon atom of the organopolysiloxane is unsubstituted or substituted having 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms. These are monovalent hydrocarbon groups. For example, alkyl groups such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, cyclohexyl group, octyl group, nonyl group, decyl group; Aryl groups such as phenyl group, tolyl group, xylyl group, naphthyl group; aralkyl groups such as benzyl group, phenylethyl group, phenylpropyl group, or part or all of hydrogen atoms of these groups are fluorine, bromine, chlorine And those substituted with a halogen atom such as cyano group, and the like, such as chloromethyl group, chloropropyl group, bromoethyl group, trifluoropropyl group, cyanoethyl group and the like. In particular, a methyl group is preferable.

The organopolysiloxane can be represented by the following average composition formula (1).
R ⁵ _a SiO _{(4-a) / 2} (1)
In the above formula, R ^{5 s} are each 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. Examples of R ⁵ include organic groups other than the aliphatic unsaturated hydrocarbon groups and aliphatic unsaturated hydrocarbon groups described above. In particular, it is preferable that 90 mol% or more of all R ⁵ is a methyl group. However, at least two of R ⁵ are aliphatic unsaturated hydrocarbon groups, preferably alkenyl groups. a is a positive number of 1.5 to 2.8, preferably 1.8 to 2.5, more preferably 1.95 to 2.05. However, the kinematic viscosity at 25 ° C. of the organopolysiloxane is 60 to 100,000 mm ² / s, preferably 600 to 100,000 mm ² / s. The structure of the organopolysiloxane is not particularly limited, and may be a straight chain, a branched chain, a partially branched or a linear chain having a cyclic structure.

  Examples of the organopolysiloxane include, for example, dimethylpolysiloxane blocked with dimethylvinylsilyl group at both ends, dimethylpolysiloxane blocked with methyldivinylsiloxy group at both ends of molecular chain, dimethylsiloxane / methylphenylsiloxane Examples include coalescence.

(B) Component (B) component is a silicone resin. The present invention is characterized in that the silicone resin has at least one aliphatic unsaturated hydrocarbon group in one molecule. When the silicone composition of this invention contains this silicone resin, the adhesive strength of the hardened | cured material obtained can be improved notably. In the present invention, the component (B) is preferably a silicone resin containing SiO _4/2 units (Q units) and R ₃ SiO _1/2 units (M units). In the above formula, Rs are each independently an unsubstituted or substituted monovalent hydrocarbon group having 1 to 18, preferably 1 to 10, more preferably 1 to 8 carbon atoms. R includes a monovalent hydrocarbon group (a group represented by R ¹ in the following) and an aliphatic unsaturated hydrocarbon group (a group represented by R ² in the following) having no aliphatic unsaturated bond. However, at least one silicone resin per molecule, preferably 1 × 10 ⁻⁵ to 1 × 10 ⁻² mol / g, more preferably 1 × 10 ⁻⁴ to 2 × 10 ⁻³ mol / g of fat. Having an unsaturated hydrocarbon group.

The molar ratio between the SiO _4/2 unit (Q unit) and the R ₃ SiO _1/2 unit (M unit) is such that (M unit) / (Q unit) satisfies 0.1 to 3.0, It is preferable that (M unit) / (Q unit) is a number satisfying 0.3 to 2.5, and in particular, (M unit) / (Q unit) is a number satisfying 0.5 to 2.0. It is preferable. When the molar ratio between the M unit and the Q unit is within the above range, a grease having good adhesion and strength can be provided. The silicone resin of the present invention contains R ₂ SiO _2/2 units (D units) and RSiO _3/2 units (T units) in the molecule to such an extent that the properties of the composition of the present invention are not impaired. Good (wherein R is the same as above).

In the present invention, the silicone resin is a solid or viscous liquid at room temperature. The average molecular weight of the silicone resin is not particularly limited, but the kinematic viscosity when the silicone resin is dissolved in xylene to form a 50% by mass solution is 0.5 to 10 mm ² / s, preferably 1.0 to 5. It should be 0 mm ² / s. The kinematic viscosity is a value measured at 25 ° C. using an Ubbelohde Ostwald viscometer. A silicone resin having a viscosity within the above range is preferable because the physical properties of the composition do not deteriorate.

Preferably, the component (B) is composed of SiO _4/2 units, R ¹ ₂ R ² SiO _1/2 units, and R ¹ ₃ SiO _1/2 units (wherein R ¹ , independently of each other, is aliphatic unsaturated. It is a monovalent hydrocarbon group having no bond, and R ² is an aliphatic unsaturated hydrocarbon group). In particular, the component (B) is represented by the following average composition formula (2).
(SiO _4/2 ) _b (R ¹ ₂ R ² SiO _1/2 ) _c (R ¹ ₃ SiO _1/2 ) _d (2)
In the above formula, b, c, and d are each a positive number, (c + d) / b is a number satisfying 0.1 to 3.0, and (c + d) / b is 0.3 to 2.5. It is preferable that the number is satisfied, and it is particularly preferable that (c + d) / b is a number satisfying 0.5 to 2.0.

R ² is an aliphatic unsaturated hydrocarbon group, preferably a monovalent hydrocarbon group having 2 to 8 carbon atoms, more preferably 2 to 6 carbon atoms, having an aliphatic unsaturated bond, more preferably An alkenyl group. Examples thereof include alkenyl groups such as vinyl group, allyl group, propenyl group, isopropenyl group, butenyl group, hexenyl group, cyclohexenyl group, and octenyl group. Particularly preferred is a vinyl group.

R ¹ is preferably an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond and having 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms. . For example, alkyl groups such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, cyclohexyl group, octyl group, nonyl group, decyl group; Aryl groups such as phenyl group, tolyl group, xylyl group, naphthyl group; aralkyl groups such as benzyl group, phenylethyl group, phenylpropyl group, and a part or all of hydrogen atoms of these groups are fluorine, bromine, chlorine, etc. Substituted with a halogen atom, a cyano group or the like, such as a chloromethyl group, a chloropropyl group, a bromoethyl group, a trifluoropropyl group, a cyanoethyl group, or the like. Particularly preferred is a methyl group.

  (B) The quantity of a silicone resin is 2-50 mass parts with respect to a total of 100 mass parts of (A) component and (B) component, Preferably it is 10-40 mass parts. If the amount of component (B) is less than the above lower limit, there is a fear that it will be insufficient to develop adhesiveness, and if it is more than the above upper limit, there is a possibility that the extensibility will be poor.

Component (C) The component (C) is a thermally conductive filler. The present invention is characterized in that the filler contains aluminum powder and zinc oxide powder, and the weight ratio of the aluminum powder to the weight of the zinc oxide powder is 1 to 10, preferably 2 to 8. Thereby, the grease which has favorable viscosity and storage stability can be provided. In addition, since the thermal conductivity of aluminum powder is about 237 W / mK and the thermal conductivity of zinc oxide powder is about 20 W / mK, in order to obtain high thermal conductivity, aluminum powder is used alone or in a high ratio. Mixing is considered. However, it is preferable to mix aluminum powder alone or in excess of the above upper limit because grease cannot be obtained, or oil separation is likely to occur in the grease over time, resulting in poor storage stability of the grease. Absent. Moreover, since the heat conductivity of the composition obtained when the compounding ratio of aluminum powder is smaller than the said lower limit will become a thing which is unpreferable.

In the present invention, the shape of the aluminum powder is not particularly limited, and examples thereof include a spherical shape and an indefinite shape. The aluminum powder may be a powder whose surface has been treated in advance.
Preferably, the aluminum powder has an average particle size of 0.1-100 μm, more preferably 1-40 μm. If the average particle size of the aluminum powder is less than the above lower limit, the resulting composition may have too high a viscosity, resulting in poor extensibility, and if it exceeds the upper limit, the resulting composition may be non-uniform. is there. In the present invention, as the aluminum powder, an aluminum powder having a large average particle diameter or an aluminum powder having a small average particle diameter may be used alone, but preferably a large average particle diameter (for example, 5 μm to 100 μm). , Preferably 10 μm or more and 100 μm or less, more preferably 10 μm or more and 40 μm or less) and a small average particle size (for example, 0.1 μm or more and less than 5 μm, preferably 0.1 μm or more and 3 μm or less, more preferably 1 μm or more) It is preferable to mix and use aluminum powder having 3 μm or less). By mixing, a grease having a good viscosity can be obtained. The mixing ratio may be adjusted according to the desired viscosity of the grease. In particular, the mass ratio of the aluminum powder having a large average particle size to the aluminum powder having a small average particle size is 0.5 to 9.0, Preferably it is 1.0-5.0.

  In the present invention, the shape of the zinc oxide powder is not particularly limited, and examples thereof include a spherical shape and an indefinite shape. Preferably, the zinc oxide powder has an average particle size of 0.1 to 10 μm, more preferably 1 to 4 μm. If the average particle size of the zinc oxide powder is less than the above lower limit, the resulting composition may have too high a viscosity, resulting in poor extensibility, and if it exceeds the above upper limit, the resulting composition will be non-uniform. There is a fear.

  In the present invention, the “average particle diameter” means a particle diameter at an integrated value of 50% in a particle size distribution obtained by a laser diffraction / scattering method. Measurement by the laser diffraction / scattering method may be performed by, for example, a microtrack particle size analyzer MT3300EX (manufactured by Nikkiso Co., Ltd.).

  In the present invention, the filler (C) includes titanium oxide powder, alumina powder, boron nitride powder, aluminum nitride powder, diamond powder, gold powder, silver powder, copper powder, carbon, in addition to the aluminum powder and zinc oxide powder. Conventionally known thermally conductive fillers such as powder, nickel powder, indium powder, gallium powder, metal silicon powder, and silica powder may be contained within a range not impairing the effects of the present invention.

  (C) The quantity of a filler is 500-2,000 mass parts with respect to a total of 100 mass parts of (A) component and (B) component, Preferably it is 800-1,200 mass parts. If the amount of the filler is less than the lower limit, the resulting composition may have poor thermal conductivity, and if it exceeds the upper limit, the composition may have poor extensibility.

Component (D) The component (D) is composed of 2 or more, preferably 3 or more, particularly 3 to 100, more preferably 3 to 20 hydrogen atoms bonded to silicon atoms (ie, SiH groups) in one molecule. This is an organohydrogenpolysiloxane. In the organohydrogenpolysiloxane, the SiH group in the molecule is an aliphatic unsaturated hydrocarbon group contained in the above-described components (A) and (B), or a component (G) described later, and a platinum group metal catalyst described below. Any one can be used as long as it undergoes an addition reaction in the presence of bismuth to form a crosslinked structure. The organohydrogenpolysiloxane is not particularly limited in its molecular structure as long as it has the above properties, and examples thereof include linear, branched, cyclic, partially branched, or linear linear structures having a cyclic structure. Preferably it is linear or cyclic.

The organohydrogenpolysiloxane has a kinematic viscosity at 25 ° C. of 1.0 to 1,000 mm ² / s, preferably 10 to 100 mm ² / s. If the kinematic viscosity is less than the lower limit, the physical properties of the composition may be deteriorated, and if it exceeds the upper limit, the extensibility of the composition may be poor. In the present invention, the kinematic viscosity is a value at 25 ° C. measured by an Ubbelohde Ostwald viscometer.

  Examples of the organic group bonded to the silicon atom of the organohydrogenpolysiloxane include monovalent hydrocarbon groups other than aliphatic unsaturated hydrocarbon groups. 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, methyl groups, ethyl groups, propyl groups, butyl groups, hexyl groups, alkyl groups such as dodecyl groups, aryl groups such as phenyl groups, aralkyl groups such as 2-phenylethyl groups and 2-phenylpropyl groups, and hydrogens thereof. Those in which part or all of the atoms are substituted with halogen atoms such as fluorine, bromine, chlorine, cyano groups, etc., such as chloromethyl group, chloropropyl group, bromoethyl group, trifluoropropyl group, cyanoethyl group, and the like, and 2- Examples include epoxy ring-containing organic groups (glycidyl group or glycidyloxy group-substituted alkyl group) such as glycidoxyethyl group, 3-glycidoxypropyl group, 4-glycidoxybutyl group and the like. The organohydrogenpolysiloxane may be used alone or in combination of two or more.

The organohydrogenpolysiloxane is represented, for example, by the following average composition formula (3).
R ³ _e H _f SiO _{(4-ef) / 2} (3)
In the formula, R ³ independently of each other is an aliphatic unsaturated hydrocarbon group having 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, which is not an aliphatic unsaturated hydrocarbon group. Is mentioned. e is a positive number of 0.7 to 2.1, preferably 0.8 to 2.05, f is a positive number of 0.001 to 1.0, preferably 0.005 to 1.0, And e + f is a number satisfying 0.8 to 3.0, preferably 1.0 to 2.5. The weight average molecular weight of the organohydrogenpolysiloxane is preferably 100 to 30,000, more preferably 500 to 10,000. The structure of the organohydrogenpolysiloxane is not particularly limited, and may be linear, branched, cyclic, partially branched, or linear having a cyclic structure.

  The amount of (D) organohydrogenpolysiloxane is such that the number of SiH groups in component (D) is 0.5 to the total number of aliphatic unsaturated hydrocarbon groups in components (A) and (B). 5, preferably 1 to 3, and more preferably 1.3 to 2.7. If the amount of the component (D) is less than the above lower limit value, sufficient adhesion performance cannot be exhibited, and the adhesion to the substrate may be deteriorated. On the other hand, if the value exceeds the upper limit, unreacted SiH groups cause an excessive crosslinking reaction, and the hardness of the cured product may increase.

Component (E) The component (E) is a platinum group metal catalyst and functions to promote the addition reaction described above. A conventionally well-known thing used for an addition reaction can be used for a platinum group metal catalyst. For example, platinum-based, palladium-based, and rhodium-based catalysts may be mentioned. Among them, platinum or platinum compounds that are relatively easily available are preferable. Examples thereof include platinum alone, platinum black, chloroplatinic acid, platinum-olefin complexes, platinum-alcohol complexes, platinum coordination compounds, and the like. A platinum-type catalyst may be used individually by 1 type or in combination of 2 or more types.

  The blending amount of the component (E) may be an effective amount as a catalyst, that is, an effective amount necessary to accelerate the addition reaction and cure the composition of the present invention. In particular, it is 0.1 to 500 ppm, more preferably 1 to 200 ppm, based on the mass based on the platinum group metal atom, based on the total mass of the component (A) and the component (B). If the amount of the catalyst is smaller than the lower limit, the effect as a catalyst may not be obtained. Further, even if the above upper limit is exceeded, the catalytic effect does not increase and is uneconomical.

Component (F) The silicone composition of the present invention can further contain a hydrolyzable methylpolysiloxane represented by the following formula (4).

In the above formula (4), R ⁴ is an alkyl group having 1 to 6 carbon atoms, methyl group, ethyl group, propyl group, isopropyl group, butyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl. Groups and the like. g is an integer of 5 to 100, preferably an integer of 10 to 60. When the value of g is smaller than the above lower limit, oil bleed derived from the silicone composition may be serious and reliability may be deteriorated. On the other hand, if the value of g is larger than the above upper limit value, the wettability with the filler may not be sufficient.

  The amount of the component (F) is an amount that is 1 to 50 parts by mass, preferably 10 to 30 parts by mass with respect to 100 parts by mass as a total of the components (A) and (B). If the amount of component (F) is less than the above lower limit, sufficient wettability may not be exhibited. Moreover, when there is more quantity of (F) component than the said lower limit, there exists a possibility that the bleeding from a composition may become intense.

(G) Component The silicone composition of the present invention may further contain (G) an adhesion assistant. The adhesion assistant is a compound having a triazine ring in one molecule and at least one aliphatic unsaturated hydrocarbon group that may have an oxygen atom, and can improve the adhesion performance of the composition.

式（５）中、Ｒ⁶は、酸素原子を有してよい脂肪族不飽和炭化水素基又は−（ＣＨ_２）_ｖ−Ｓｉ（ＯＲ^７）_３で示される基である（式中、Ｒ^７は水素原子又は炭素数１〜６の１価炭化水素基であり、ｖは１〜６、特には１〜４の整数である）。但し、Ｒ^６の少なくとも１は脂肪族不飽和炭化水素基である。Ｒ^６としては、好ましくは炭素数２〜８、更に好ましくは炭素数２〜６の、直鎖状又は分岐を有するアルケニル基、例えば、ビニル基、アリル基、１−ブテニル基、１−ヘキセニル基、及び２−メチルプロペニル基、又は（メタ）アクリル基等が挙げられる。中でも、コストの観点からアリル基が好ましい。 The component (G) can be represented by the following general formula (5).

In the formula (5), R ⁶ is an aliphatic unsaturated hydrocarbon group which may have an oxygen atom or a group represented by — (CH ₂ ) _v —Si (OR ⁷ ) ₃ (wherein R ⁷ Is a hydrogen atom or a monovalent hydrocarbon group having 1 to 6 carbon atoms, and v is an integer of 1 to 6, particularly 1 to 4. However, at least 1 of R ⁶ is an aliphatic unsaturated hydrocarbon group. R ⁶ is preferably a linear or branched alkenyl group having 2 to 8 carbon atoms, more preferably 2 to 6 carbon atoms, such as a vinyl group, an allyl group, a 1-butenyl group, or a 1-hexenyl group. And 2-methylpropenyl group or (meth) acryl group. Among these, an allyl group is preferable from the viewpoint of cost.

  As the component (G), an alkoxy group in which an alkoxysilyl group such as 1-2 trimethoxysilyl groups is added to 1-2 allyl groups of triallyl isocyanurate, trimethacryl isocyanurate, and triallyl isocyanurate. Examples include silyl-substituted / triallyl isocyanurate and siloxane-modified products (derivatives) that are hydrolyzed condensates thereof.

  The amount of the component (G) is 0.05 to 0.5 parts by mass, preferably 0.05 to 0.3 parts by mass with respect to 100 parts by mass in total of the components (A) and (B). . If it is less than the lower limit, the composition may not exhibit sufficient adhesion performance, and if it exceeds the upper limit, the addition reaction may not proceed sufficiently and the adhesion performance may not be exhibited. In addition, when a silicone composition contains (G) component, the amount of (D) organohydrogenpolysiloxane mentioned above is the aliphatic unsaturated carbonization in (A) component, (B) component, and (G) component. The amount of SiH groups in component (D) relative to the total number of hydrogen groups is 0.5 to 5, preferably 1 to 3, and more preferably 1.3 to 2.7.

(H) Component The silicone composition of the present invention may further contain (H) a control agent. The control agent functions to suppress the progress of the hydrosilylation reaction at room temperature and prolong the shelf life and pot life. As the control agent, a conventionally known control agent used in addition-curable silicone compositions can be used. For example, acetylene compounds such as acetylene alcohols (for example, 1-ethynyl-1-cyclohexanol, 3,5-dimethyl-1-hexyn-3-ol), various nitrogen compounds such as tributylamine, tetramethylethylenediamine, and benzotriazole And organic phosphorus compounds such as triphenylphosphine, oxime compounds, and organic chloro compounds.

  The amount of the component (H) is 0.05 to 0.6 parts by mass, preferably 0.1 to 0.5 parts by mass, with respect to 100 parts by mass in total of the components (A) and (B). If the amount of the control agent is less than the above lower limit value, the desired sufficient shelf life and pot life may not be obtained, and if it exceeds the upper limit value, the curability of the silicone composition may be lowered. The control agent may be used after diluted with toluene or the like in order to improve dispersibility in the silicone composition.

  Moreover, in order to prevent deterioration of the composition, the silicone composition of the present invention may contain a conventionally known antioxidant such as 2,6-di-t-butyl-4-methylphenol as necessary. Good. Further, dyes, pigments, flame retardants, anti-settling agents, thixotropic agents, and the like can be blended as necessary within a range that does not impair the object of the present invention.

  The method for producing the silicone composition of the present invention is not particularly limited as long as it follows the conventional method for producing a silicone grease composition. For example, the above-mentioned components (A) to (H), and other components as necessary, are trimix, twin mix, planetary mixer (all are registered trademarks of mixer manufactured by Inoue Seisakusho Co., Ltd.), ultra mixer (Mizuho Industry Co., Ltd.) It can be manufactured by a method of mixing with a mixer such as a registered trademark of a mixer manufactured by (Co., Ltd.), Hibis Disper Mix (registered trademark of a mixer manufactured by Special Machine Industries Co., Ltd.).

  The silicone composition of the present invention preferably has a viscosity of 10 to 1,000 Pa · s measured at 25 ° C., more preferably 50 to 1,000 Pa · s. If the viscosity is higher than the upper limit, workability is deteriorated, which is not preferable. The viscosity can be obtained by adjusting the blending of each component described above. In the present invention, the viscosity is a value of 25 ° C. measured with a Malcolm viscometer (rotor A: 10 rpm, displacement speed: 6 [1 / s]).

  The silicone composition of the present invention can be suitably used to dissipate heat by transferring heat from the heat generating member to the cooling member by interposing between the electronic component such as LSI or other heat generating member and the cooling member, It can be used in the same manner as conventional heat conductive silicone grease. For example, the silicone composition of the present invention can be cured by heat generated from a heat generating member such as an electronic component. Moreover, after apply | coating the silicone composition of this invention, you may heat-harden actively. Thereby, the semiconductor device which interposed the hardened | cured material of the silicone composition of this invention between the heat generating member and the cooling member can be provided. The curing conditions for heat curing the silicone composition of the present invention are not particularly limited, but are usually 80 to 200 ° C., preferably 100 to 180 ° C., 30 minutes to 4 hours, preferably 30 minutes to 2 It's time. Since the silicone composition of the present invention has high thermal conductivity and good adhesiveness, it can be particularly suitably used as a heat dissipating grease for high-quality semiconductor devices and the like.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated in detail, this invention is not restrict | limited to the following Example. In the following, the kinematic viscosity is a value measured at 25 ° C. with an Ubbelohde Ostwald viscometer (manufactured by Shibata Kagaku Co., Ltd.).

Each component used in the examples and comparative examples is described below.
(A) Component A-1: Dimethylpolysiloxane having both ends blocked with dimethylvinylsilyl groups and kinematic viscosity at 25 ° C. of 600 mm ² / s A-2: Both ends blocked with dimethylvinylsilyl groups, 25 ° C. Dimethylpolysiloxane having a kinematic viscosity at 5,000 mm ² / s

(B) Component B-1: Silicone resin represented by the following average composition formula: Kinematic viscosity of 50 mm% solution in xylene solvent 3.0 mm ² / s
(SiO _4/2 ) _1.0 ((CH ₂ ═CH) (CH ₃ ) ₂ SiO _1/2 ) _0.12 ((CH ₃ ) ₃ SiO _1/2 ) _0.75
B-2: Silicone resin represented by the following average composition formula: Kinematic viscosity 1.5 mm ² / s when a 50% by mass solution in a xylene solvent is used.
(SiO _4/2 ) _1.0 ((CH ₂ ═CH) (CH ₃ ) ₂ SiO _1/2 ) _0.25 ((CH ₃ ) ₃ SiO _1/2 ) _1.5

In Comparative Example 8, the following silicone resin was used.
B-3: Silicone resin represented by the following average composition formula: Kinematic viscosity 2.8 mm ² / s when a 50% by mass solution in a xylene solvent is used.
(SiO _4/2 ) _1.0 ((CH ₃ ) ₃ SiO _1/2 ) _0.87

(C) Component C-1: Aluminum powder having an average particle size of 2.0 μm (thermal conductivity: 237 W / m · ° C.)
C-2: Aluminum powder having an average particle diameter of 20.0 μm (thermal conductivity: 237 W / m · ° C.)
C-3: Zinc oxide powder having an average particle diameter of 1.0 μm (thermal conductivity: 25 W / m · ° C.)

Ｄ−２：

(D) Component D-1:

D-2:

(E) Component E-1: Solution in which a platinum-divinyltetramethyldisiloxane complex is dissolved in the same dimethylpolysiloxane as the above A-1 (platinum atom content: 1% by mass)

(F) Component F-1:

(G) Component G-1:

(H) Component H-1: 1-ethynyl-1-cyclohexanol

[Examples 1-8, Comparative Examples 1-8]
Preparation of Silicone Composition The above-mentioned components (A) to (H) were blended by the method shown below according to the blending amounts shown in Tables 1 and 2 below to prepare silicone compositions. In Table 1, the mass of the component (E) is the mass of a solution (platinum atom content: 1 mass%) in which a platinum-divinyltetramethyldisiloxane complex is dissolved in dimethylpolysiloxane. SiH / SiVi (number ratio) is the ratio of the number of SiH groups in component (D) to the total number of alkenyl groups in component (A), component (B), and component (G).

  Components (A), (B), (C), and (F) were added to a 5-liter planetary mixer (manufactured by Inoue Seisakusho Co., Ltd.) and mixed at 170 ° C. for 1 hour. The mixture was cooled to room temperature, and then the components (D), (E), (G), and (H) were added and mixed uniformly to prepare a silicone composition.

About each composition obtained by the said method, the viscosity, heat conductivity, elongation at the time of cutting | disconnection, and adhesive strength were measured in accordance with the following method. The results are shown in Tables 1 and 2.
[viscosity]
The absolute viscosity of each composition was measured at 25 ° C. using a Malcolm viscometer (type PC-1T).
[Thermal conductivity]
Each composition was wrapped in kitchen wrap, and the thermal conductivity was measured with TPA-501 manufactured by Kyoto Electronics Industry Co., Ltd.
[Elongation at cutting]
Each composition was heated and cured at 150 ° C. for 90 minutes to prepare a 2 mm thick sheet, and then a No. 2 dumbbell shape was prepared according to JIS K6251 and the elongation at break was measured.
[Adhesive strength]
Each composition was sandwiched between a 1 mm × 1 mm silicon wafer and a nickel plate and heated at 150 ° C. for 60 minutes while being pressed with a 1.8 kgf clip. Thereafter, the adhesive strength was measured using Dage series-4000PXY (manufactured by Dage Deutschland GmbH).

  As shown in Table 2, the composition of Comparative Example 1 containing no silicone resin has low adhesive strength. The compositions of Comparative Examples 2 and 3 having too much silicone resin are not greases. The composition of Comparative Example 4 having too little filler content has low thermal conductivity. The composition of Comparative Example 5 in which the amount of the filler is too large does not become grease. The composition of Comparative Example 6 in which the blending ratio of the aluminum powder is too large with respect to the zinc oxide powder does not become grease. The composition of Comparative Example 7 in which the blending ratio of the aluminum powder is too small relative to the zinc oxide powder has a low thermal conductivity. In addition, the composition of Comparative Example 8 in which the silicone resin does not have an aliphatic unsaturated hydrocarbon group has low adhesive strength, and low viscosity and elongation at break. On the other hand, as shown in Table 1, the silicone composition of the present invention has high thermal conductivity and good adhesiveness.

Since the silicone composition of the present invention has high thermal conductivity and good adhesion, it can be suitably used as a heat dissipating grease for semiconductor devices and the like.

Claims (9)

(A) an organopolysiloxane having at least two aliphatic unsaturated hydrocarbon groups in one molecule and a kinematic viscosity at 25 ° C. of 60 to 100,000 mm ² / s,
(B) Silicone resin having at least one aliphatic unsaturated hydrocarbon group in one molecule: 2 to 50 parts by mass with respect to 100 parts by mass in total of (A) component and (B) component,
(C) Filler containing aluminum powder and zinc oxide powder, and the weight ratio of aluminum powder to the weight of zinc oxide powder is 1 to 10: 500 for a total of 100 parts by mass of component (A) and component (B) ~ 2,000 parts by mass,
(D) Organohydrogenpolysiloxane having two or more hydrogen atoms bonded to silicon atoms (that is, SiH groups) in one molecule: (A) component and aliphatic unsaturated hydrocarbon in component (B) (D) the amount by which the number of SiH groups in the component is 0.5-5 with respect to the total number of groups, and (E) a platinum group metal catalyst: a silicone composition containing an effective amount. (B) The silicone resin is composed of SiO _4/2 units (Q units) and R ₃ SiO _1/2 units (M units) (wherein R is independently of each other, unsubstituted or substituted, having 1 to 18 carbon atoms. Which is a monovalent hydrocarbon group, provided that the silicone resin has at least one aliphatic unsaturated hydrocarbon group, and the molar ratio of Q units to M units (M units) / (Q units) is The silicone composition of Claim 1 which is 0.1-3.0. (F) The following general formula (4)

(Wherein R ⁴ is an alkyl group having 1 to 6 carbon atoms, and g is an integer of 5 to 100)
The hydrolyzable methylpolysiloxane represented by the formula (1) is further contained in an amount of 1 to 50 parts by mass with respect to 100 parts by mass in total of the component (A) and the component (B). Silicone composition.   (G) A bonding agent having a triazine ring and at least one aliphatic unsaturated hydrocarbon group which may have an oxygen atom in one molecule is the sum of the component (A) and the component (B). The silicone composition of any one of Claims 1-3 further contained in the quantity used as 0.05-0.5 mass part with respect to 100 mass parts.   (H) One or more control agents selected from the group consisting of an acetylene compound, a nitrogen compound, an organic phosphorus compound, an oxime compound and an organic chloro compound are added in a total of 100 parts by mass of the component (A) and the component (B). The silicone composition according to any one of claims 1 to 4, further contained in an amount of 0.05 to 0.6 parts by mass. (B) Silicone resin is _composed of SiO _4/2 unit, R ¹ ₂ R ² SiO _1/2 unit, and R ¹ ₃ SiO _1/2 unit (wherein R ¹ is an aliphatic unsaturated bond independently of each other) a monovalent hydrocarbon group having no, R ² consists of a is) aliphatic unsaturated hydrocarbon group, the silicone composition of any one of claims 2-5. (C) The silicone composition of any one of Claims 1-6 whose weight ratio of the aluminum powder with respect to the weight of a zinc oxide powder is 4.5-10 in a filler. A grease comprising the silicone composition according to any one of claims 1 to 7 . 9. The semiconductor device having a heat generating member and a cooling member, wherein the heat generating member and the cooling member are joined via the grease according to claim 8.