Silicone composition

Abstract

As a silicone composition capable of forming a silicone grease having high thermal conductivity and good adhesion compared to conventional silicone grease, provided is a silicone composition containing: (A) an organopolysiloxane having at least two aliphatic unsaturated hydrocarbon groups in one molecule and having a kinematic viscosity at 25 DEG C of 60-100,000 mm2 / s; (B) a hydrolyzable organopolysiloxane represented by general formula (1); (C) at least one thermally conductive filler selected from the group consisting of metal oxides and metal nitrides; (D) an organohydrogenpolysiloxane represented by general formula (2); (E) an organohydrogenpolysiloxane represented by general formula (3); (F) a hydrolyzable organopolysiloxane represented by general formula (4); (G) a platinum group metal catalyst; and (H) a reaction control agent.

Description

TECHNICAL FIELD

[0001] The present application relates to a silicone composition. Specifically, it relates to a silicone composition which can form a silicone grease having high thermal conductivity, and to a silicone composition which can form a grease having good adhesion even if a large amount of a thermally conductive filler is contained. BACKGROUND

[0002] For electronic parts such as LSI, IC chip, heat dissipation in use and performance reduction caused thereby have been known, and as a means for solving the same, various heat dissipation techniques have been used. As a general method, by disposing a cooling member in the vicinity of a heat dissipation part so that they are in close contact, and efficiently removing heat from the cooling member, heat dissipation is performed. At this time, if there is a gap between the heat dissipation member and the cooling member, the thermal conductivity is reduced due to the intervention of air having poor thermal conductivity, and the temperature of the heat dissipation member becomes unable to sufficiently decrease. In order to prevent such a phenomenon, in order to prevent the intervention of air, a heat dissipation material having good thermal conductivity, such as a heat dissipation grease, a heat dissipation sheet, which has followability to the surface of the member, is used.

[0003] In the heat dissipation grease, in order to firmly bond the semiconductor chip and the heat sink, there is a grease in which adhesion has been imparted to the grease. If the semiconductor chip and the heat sink are not sufficiently bonded via the grease, the heat dissipation performance cannot be sufficiently exerted, and sometimes significant performance reduction occurs. Therefore, it is important to firmly bond the semiconductor chip and the heat sink with each other using the grease. However, in order to improve the thermal conductivity of the heat dissipation grease, it is also necessary to fill a thermally conductive filler in a large amount. If the thermally conductive filler is added in a large amount in the grease, there is a problem that the adhesion of the obtained cured product decreases. If the adhesion decreases, the cured product cannot follow the deformation of the semiconductor chip caused by the thermal history of heat dissipation and cooling, peeling occurs, and in the worst case, it is known that the breakage of the semiconductor chip can occur.

[0004] In Patent Literature 1, a thermally conductive silicone grease composition containing an organopolysiloxane containing an alkenyl group, a thermally conductive filler, an organohydrogenpolysiloxane, an organohydrogenpolysiloxane having at least one of an alkoxysilyl group and an epoxy group, and a platinum-based catalyst as essential components is described. However, observing the examples, the thermal conductivity does not exceed 2.0 W / mK, which is insufficient.

[0005] Patent Document 2 describes a heat conductive silicone grease composition containing, as essential components, an organopolysiloxane containing an alkenyl group, a hydrolyzable methylpolysiloxane, a heat conductive filler, an organohydrogenpolysiloxane, a bonding aid containing a triazine ring and an alkenyl group, and a platinum-based catalyst. However, observing the examples, the thermal conductivity does not exceed 3.0 W / mK, which is insufficient. In Patent Document 3, a heat conductive silicone composition containing a silicone resin having an aliphatic unsaturated hydrocarbon group is described, and it is described that the composition can provide a heat dissipation grease having high adhesion. However, observing the examples, the thermal conductivity does not exceed 4.0 W / mK, which is insufficient.

[0006] In recent years, in semiconductor devices of high-grade models, the amount of heat dissipation during operation is increasing. However, existing silicone greases have problems of insufficient thermal conductivity, and high thermal conductivity but low adhesion.

[0007] Prior Art Documents

[0008] Patent Documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 2012-067153

[0010] Patent Document 2: Japanese Patent Application Publication No. 2012-102283

[0011] Patent Document 3: Japanese Patent Application Publication No. 2016-053140 SUMMARY

[0012] Problems to be Solved by the Invention

[0013] The present invention was made in view of the above-described actual circumstances, and aims to provide a silicone composition that can provide a silicone grease having high thermal conductivity and good adhesion, compared to existing silicone greases.

[0014] Means for Solving the Problems

[0015] The present inventors made intensive studies in order to achieve the above-described object, and as a result, found that a silicone composition containing an organopolysiloxane containing an aliphatic unsaturated hydrocarbon group, an organopolysiloxane having a hydrolyzable group, a heat conductive filler, an organohydrogenpolysiloxane having a specific structure, and a platinum group metal catalyst can form a silicone grease having good adhesion even if the heat conductive filler is contained in a large amount, and completed the present invention.

[0016] That is, the present invention provides a silicone composition described below.

[0017] 1. A silicone composition containing the following (A) to (D) components:

[0018] (A) an organopolysiloxane having at least two aliphatic unsaturated hydrocarbon groups in one molecule, a kinematic viscosity at 25°C of 60 to 100,000 mm 2 / s: 100 parts by mass,

[0019] (B) a hydrolyzable organopolysiloxane represented by the following general formula (1): 100 to 600 parts by mass,

[0020] [Chem. 1]

[0021]

[0022] (in the formula, R 1 independently of one another, an alkyl group having 1 to 6 carbon atoms, and r is an integer of 5 to 100),

[0023] (C) a thermally conductive filler selected from at least one of a metal oxide and a metal nitride: 4001 to 12000 parts by mass,

[0024] (D) an organohydrogenpolysiloxane represented by the following general formula (2): 1.0 to 8.0 parts by mass,

[0025] [Chem. 2]

[0026]

[0027] (in the formula, n and m are each a number greater than 0, and are numbers satisfying 5.0 ≤ n + m ≤ 100, n / (n + m) ≤ 0.5, R 2 independently of one another, an alkyl group having 1 to 6 carbon atoms.)

[0028] (E) an organohydrogenpolysiloxane represented by the following general formula (3): 1.0 to 7.0 parts by mass,

[0029] [Chem. 3]

[0030]

[0031] (in the formula, o is an integer of 1 to 8, R 3 independently of one another, a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or R 4 however, 2 or 3 of the groups represented by R 3 are hydrogen atoms. The R 4 is a group selected from an epoxy group, an acryloyl group, a methacryloyl group, an ether group, and a trialkoxysilyl group, which is bonded to a silicon atom via a carbon atom or an oxygen atom,

[0032] (F) a hydrolyzable organopolysiloxane represented by the following general formula (4): 1 to 30 parts by mass,

[0033] [Chem. 4]

[0034]

[0035] (In the formula, p, q are each a number of 1.0 or more, and are numbers satisfying 5.0 ≤ p + q ≤ 100, R 5 are each independently an alkyl group having 1 to 6 carbon atoms, R 6 is an alkenyl group having 2 to 6 carbon atoms.

[0036] (G) Platinum group metal catalyst: effective amount

[0037] (H) Reaction control agent: 0.05 to 5.0 parts by mass.

[0038] 2. The silicone composition according to 1, wherein the (C) component comprises the following (C-l) to (C-3) components,

[0039] (C-l) aluminum nitride particles having an average particle diameter of 10 μm or more and less than 30 μm, and a residual fraction of less than 1.0 mass% with respect to a 200 mesh metal screen,

[0040] (C-2) a metal oxide or metal nitride having an average particle diameter of 1 μm or more and less than 10 μm,

[0041] (C-3) a metal oxide or metal nitride having an average particle diameter of 0.1 μm or more and less than 1 μm.

[0042] 3. The silicone composition according to 1 or 2, wherein the thermal conductivity of the cured product is 4.0 W / m-K or more.

[0043] 4. A semiconductor device in which a cured product of a silicone composition is interposed between a heat radiating member and a cooling member, a layer of the cured product comprising a cured product of the silicone composition according to any one of 1 to 3, and having a thickness of 100 μm or less.

[0044] 5. A method for producing a silicone composition according to 2, comprising a step of previously mixing the (C-l) to (C-3) components with the (A) component and the (B) component.

[0045] Effects of the Invention

[0046] The silicone composition of the present application has good adhesiveness even if a large amount of a thermally conductive filler is contained, and thus can provide a silicone grease having high thermal conductivity and good adhesiveness. DETAILED DESCRIPTION

[0047] The present application is described in detail below.

[0048] [(A) Component]

[0049] (A) Component is an organopolysiloxane having at least two aliphatic unsaturated hydrocarbon groups in one molecule, a kinematic viscosity at 25°C of 60 to 100,000 mm 2 The aliphatic unsaturated hydrocarbon group preferably has a monovalent hydrocarbon group having 2 to 8 carbon atoms of an aliphatic unsaturated bond, more preferably a monovalent hydrocarbon group having 2 to 6 carbon atoms of an aliphatic unsaturated bond, and further preferably an alkenyl group.

[0050] As specific examples of the aliphatic unsaturated bond, there can be mentioned vinyl group, allyl group, propenyl group, isopropenyl group, butenyl group, hexenyl group, cyclohexenyl group, and octenyl group, and the like. The vinyl group is particularly preferred. The aliphatic unsaturated hydrocarbon group can be bonded to either of the silicon atom at the end of the molecular chain, the silicon atom in the middle of the molecular chain, or both.

[0051] The organopolysiloxane has a kinematic viscosity at 25°C of 60 to 100,000 mm 2 / s, and preferably 100 to 30,000 mm 2 / s. If the kinematic viscosity is less than 60 mm 2 / s, the physical properties of the silicone composition can be reduced, and if it exceeds 100,000 mm 2 / s, the stretchability of the silicone composition can be lacking. In the present application, the kinematic viscosity is the value at 25°C measured using a U-type Ostwald viscometer. The organopolysiloxane described above is not particularly limited in the molecular structure as long as it has the properties described above, and there can be mentioned straight-chain, branched-chain, straight-chain with a part of the branched or cyclic structure, and the like.

[0052] In particular, as the organopolysiloxane, there is preferably an organopolysiloxane having a straight-chain structure in which the main chain is composed of repeating diorganosiloxane units and both ends of the molecular chain are capped with triorganosiloxy groups. The organopolysiloxane having the straight-chain structure can partially have a branched-chain structure or a cyclic structure. The organopolysiloxane can be used alone or in combination of two or more.

[0053] The organic group other than the aliphatic unsaturated hydrocarbon group bonded to the silicon atom of the organopolysiloxane described above is preferably an unsubstituted or substituted monovalent hydrocarbon group having 1 to 18 carbon atoms, more preferably an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, and further preferably an unsubstituted or substituted monovalent hydrocarbon group having 1 to 8 carbon atoms.

[0054] As specific examples of the above-mentioned unsubstituted or substituted monovalent hydrocarbon group, there can be mentioned alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, amyl, neopentyl, hexyl, cyclohexyl, octyl, nonyl, decyl and the like; aryl groups such as phenyl, tolyl, xylyl, naphthyl and the like; aralkyl groups such as benzyl, phenylethyl, phenylpropyl and the like; or groups in which a part or all of the hydrogen atoms of these groups are substituted with halogen atoms such as fluorine, bromine, chlorine and the like, a cyano group or the like, for example, chloromethyl, chloropropyl, bromoethyl, trifluoropropyl, cyanoethyl and the like. Methyl group is particularly preferred.

[0055] [(B) component]

[0056] The (B) component is a hydrolyzable organopolysiloxane represented by the following general formula (1).

[0057] [Chemical Formula 5]

[0058]

[0059] (In the formula, R 1 independently of one another, an alkyl group having 1 to 6 carbon atoms, and r is an integer of 5 to 100)

[0060] The above-mentioned R 1 is an alkyl group having 1 to 6 carbon atoms, and as specific examples thereof, there can be mentioned methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, t-butyl, amyl, hexyl and the like, with methyl, ethyl, propyl, isopropyl and butyl being preferred, and methyl being more preferred.

[0061] The above-mentioned r is an integer of 5 to 100, and is preferably an integer of 10 to 60. If the value of r is smaller than the above-mentioned lower limit value, bleeding from the silicone composition becomes severe, and reliability can become poor. On the other hand, if the value of r is larger than the above-mentioned upper limit value, wettability with the filler can become insufficient.

[0062] The amount of the (B) component is an amount of 100 to 600 parts by mass, relative to 100 parts by mass of the (A) component, and is preferably an amount of 100 to 300 parts by mass, and more preferably an amount of 200 to 300 parts by mass. If the amount of the (B) component is less than the above-mentioned lower limit value, sufficient wettability can not be exerted. On the other hand, if the amount of the (B) component is more than the above-mentioned upper limit value, bleeding from the composition becomes severe, and adhesion is reduced.

[0063] [(C) component]

[0064] (C) a thermally conductive filler selected from at least one of metal oxides and metal nitrides. As specific examples of the (C) component, there can be mentioned aluminum nitride powder, alumina powder, zinc oxide powder, magnesium oxide powder, and the like. The (C) component can be used alone as one kind or in combination of two or more, but is preferably one or more selected from the group consisting of aluminum nitride powder, alumina powder, and zinc oxide powder. Further, the (C) component preferably contains the following (C-l) to (C-3) components.

[0065] (C-l) aluminum nitride having an average particle diameter of 10 μm or more and less than 30 μm

[0066] (C-2) aluminum nitride or alumina having an average particle diameter of 1 μm or more and less than 10 μm

[0067] (C-3) zinc oxide, aluminum nitride, or alumina having an average particle diameter of 0.1 μm or more and less than 1 μm

[0068] The (C) component can further increase the amount of the thermally conductive filler by being a combination of the above (C-l) to (C-3) components, and can improve the thermal conductivity of the resulting composition.

[0069] The (C-l) component is aluminum nitride having an average particle diameter of 10 μm or more and less than 30 μm, and is preferably aluminum nitride having an average particle diameter of 15 μm or more and 25 μm or less. By having an average particle diameter in the above range, both high thermal conductivity and stability can be achieved. Further, the (C-l) component preferably has a residue of 1.0 mass% or less, more preferably 0.5 mass% or less, and further preferably 0.1 mass% or less, with respect to the residue of 200 mesh metal screen. Further, it is further preferred to have a residue of 1.0 mass% or less, particularly 0.5 mass% or less, and most preferably 0.1 mass% or less, with respect to the residue of 325 mesh metal screen. It should be noted that the 200 mesh metal screen and the 325 mesh metal screen used herein are metal screens defined in JIS Z 8801. By having a residue of 1.0 mass% or less of the (C-l) component with respect to the residue of 200 mesh metal screen, the thickness of the coating film of the composition interposed between the heat dissipating member and the cooling member in the semiconductor device can be made sufficiently thin.

[0070] Further, as the shape of the (C-l) component, broken, polyhedron, circle, and spherical shape can be given, and a circle is preferred. In the present application, the "average particle diameter" means the particle diameter at the cumulative value of 50% in the particle size distribution on a volume basis, which is measured by a laser diffraction scattering method. The measurement by the laser diffraction scattering method can be performed, for example, by using a Microtrac particle size analyzer MT3300EX (manufactured by Nikkiso Co., Ltd.). Furthermore, in order to improve the filling property, reduce the viscosity of the composition, and prevent the precipitation of the filler, it is preferred to include the (C-2) component and the (C-3) component in addition to the (C-l) component. The viscosity of the composition of the three-component system of the (C-l) to (C-3) components becomes lower than that of the two-component system of the (C-l) component and the (C-2) component, and further, the adhesion at the time of curing is improved.

[0071] The average particle diameter of the (C-2) component is preferably 1 to 10 μm, more preferably 2 to 8 μm, and further preferably 3 to 7 μm. If the average particle diameter is 1 to 10 μm, a uniform composition is obtained when the (C-l) component is mixed with the (C-2) component and the (C-3) component in the (A) component and the (B) component, the viscosity of the composition becomes lower, and further, the adhesion at the time of curing is improved.

[0072] The average particle diameter of the (C-3) component is preferably 0.1 to 1 μm. If the (C-3) component is 1 μm or more, the viscosity of the silicone composition that can be obtained is likely to increase, or the extensibility is likely to become poor.

[0073] The amount of the (C) component is 4001 to 12000 parts by mass, and preferably 5000 to 12000 parts by mass, relative to 100 parts by mass of the (A) component. If the amount of the filler is less than 4001 parts by mass, the thermal conductivity of the composition that is obtained is likely to become poor, and if it exceeds 12000 parts by mass, the composition is likely to become poor in extensibility.

[0074] The (C) component preferably contains 50 to 90 mass% of the (C-l) component and the (C-2) component, more preferably 50 to 80 mass%, and further preferably 50 to 70 mass%, relative to the entire (C) component. If the amount of the (C-l) and (C-2) components is less than 50 mass%, the thermal conductivity is likely to decrease. Further, if the amount of the (C-l) and (C-2) components exceeds 90 mass%, the composition is likely to become non-uniform.

[0075] Further, the content ratio of the (C-l) component to the (C-2) component is preferably 50:50 to 95:5, and preferably 60:40 to 80:20, on a mass basis. If the content ratio of the (C-l) component is less than 50, the thermal conductivity is likely to decrease. Further, if the content ratio of the (C-l) component exceeds 95, the adhesion is likely to decrease.

[0076] [(D) component]

[0077] The (D) component is an organohydrogenpolysiloxane. The SiH group in the molecule of this organohydrogenpolysiloxane is addition-reacted with the aliphatic unsaturated hydrocarbon group in the composition in the presence of a platinum group metal catalyst described later, to form a crosslinked structure. This organohydrogenpolysiloxane is represented by the following general formula (2).

[0078] [Chemical Formula 6]

[0079]

[0080] (In the formula, n, m are each a number larger than 0, and are numbers satisfying 5.0 < n + m < 100, n / (n + m) < 0.5, R 2 each independently a C1-6 alkyl group)

[0081] Further, this organohydrogenpolysiloxane must not have a SiH group at the end of the molecular chain. In the case where an organohydrogenpolysiloxane having a SiH group at the end of the molecular chain is used, the storage properties of the silicone composition are significantly reduced. Furthermore, n, m satisfy 5.0 < n + m < 100, and preferably 10 < n + m < 80. In the case where n + m is less than 5.0, the physical properties of the silicone composition can be reduced, and in the case where n + m is larger than 100, the silicone composition can become lacking in stretchability. In addition, n, m satisfy n / (n + m) < 0.5, and preferably n / (n + m) < 0.3. In the case where n / (n + m) is larger than 0.5, the adhesion of the silicone composition can be reduced. 2 each independently a C1-6 alkyl group, and as specific examples thereof, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a t-butyl group, a pentyl group, a hexyl group, and the like can be given. This organohydrogenpolysiloxane can be used alone as one kind, or two or more kinds can be used in combination.

[0082] The amount of the (D) component is 1.0 to 8.0 parts by mass, and preferably 1.2 to 7.0 parts by mass, relative to 100 parts by mass of the (A) component. If the amount of the (D) component is less than 1.0 part by mass, the curing properties of the cured product of the obtained composition can be lacking or reduced, and if it exceeds 8.0 parts by mass, the hardness of the cured product of the composition can increase.

[0083] [(E) component]

[0084] The (E) component is an organohydrogenpolysiloxane. The SiH group in the molecule of this organohydrogenpolysiloxane is addition-reacted with the aliphatic unsaturated hydrocarbon group in the composition in the presence of a platinum group metal catalyst described later, to form a crosslinked structure, and at the same time, to impart adhesion to the silicone composition. This organohydrogenpolysiloxane is represented by the following general formula (3).

[0085] [Chem. 7]

[0086]

[0087] (In the formula, o is an integer of 1 to 8, R 3 independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or R 4 However, 2 or 3 of the groups represented by R 3 independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or R 4 are groups selected from the group consisting of an epoxy group, an acryl group, a methacryl group, an ether group, and a trialkoxysilyl group, which are bonded to the silicon atom via a carbon atom or an oxygen atom. )

[0088] independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or R 3 independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or R 4 However, 2 or 3 of the groups represented by R 3 independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or R 4 are groups selected from the group consisting of an epoxy group, an acryl group, a methacryl group, an ether group, and a trialkoxysilyl group, which are bonded to the silicon atom via a carbon atom or an oxygen atom, and have an effect of imparting adhesion to the silicone composition. In addition, R 3 independently an alkyl group having 1 to 6 carbon atoms, and as specific examples thereof, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a t-butyl group, a pentyl group, a hexyl group, and the like can be given. The organohydrogenpolysiloxane can be used alone as one kind, or two or more kinds can be used in combination.

[0089] The amount of the (E) component is 1.0 to 7.0 parts by mass, and preferably 1.5 to 7.0 parts by mass, relative to 100 parts by mass of the (A) component. If the amount of the (D) component is less than 1.0 part by mass, the adhesion of the obtained composition decreases. If it exceeds 7.0 parts by mass, the hardness of the cured product of the composition can decrease.

[0090] [(F) component]

[0091] The (F) component is a hydrolyzable organopolysiloxane for imparting wettability to the thermally conductive filler, and imparting adhesion to the silicone composition. The hydrolyzable organopolysiloxane is represented by the following general formula (4).

[0092] [Chem. 8]

[0093]

[0094] (In the formula, p and q are each a number of 1.0 or more, and are numbers satisfying 5.0 ≤ p + q ≤ 100, R 5 independently an alkyl group having 1 to 6 carbon atoms, and R 6is an alkenyl group having 2 to 6 carbon atoms.

[0095] p and q satisfy 5.0 ≤ p + q ≤ 100, preferably 10 ≤ p + q ≤ 60. If p + q is less than 5.0, bleeding from the silicone composition becomes severe, and reliability can deteriorate. In addition, in the case where p + q is greater than 100, wettability with the filler can become insufficient.

[0096] R 5 independently, an alkyl group having 1 to 6 carbon atoms, and as specific examples thereof, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a t-butyl group, a pentyl group, a hexyl group, and the like can be given. In addition, R 6 is an alkenyl group having 2 to 6 carbon atoms, and as specific examples thereof, a vinyl group, an allyl group, a propenyl group, an isopropenyl group, a butenyl group, a hexenyl group, a cyclohexenyl group, and the like can be given.

[0097] The amount of the (F) component is 1 to 30 parts by mass, preferably 3 to 25 parts by mass, and more preferably 5 to 20 parts by mass, with respect to 100 parts by mass of the (A) component. If the amount of the (F) component is less than the above lower limit, it can not be possible to exert sufficient wettability and adhesiveness. In addition, if the amount of the (F) component is more than the above upper limit, bleeding of the cured product obtained by using the composition of the present application can become severe.

[0098] [(G) component]

[0099] The (G) component is a platinum group metal catalyst, and functions to promote the above addition reaction. The platinum group metal catalyst can use a platinum group metal catalyst conventionally known for an addition reaction. For example, a platinum-based, palladium-based, or rhodium-based catalyst can be given, and among these, platinum or a platinum compound, which is relatively easily available, is preferred. As specific examples of the platinum-based catalyst, a platinum simple substance, platinum black, chloroplatinic acid, a platinum-olefin complex, a platinum-alcohol complex, a platinum coordination compound, and the like can be given. The platinum-based catalyst can be used alone as one kind, or two or more kinds can be used in combination.

[0100] The amount of the (G) component is only required to be an effective amount as a catalyst, that is, an effective amount required for curing the composition of the present application by promoting the addition reaction. In particular, with respect to the entire composition, it is preferred that the amount be 0.1 to 500 ppm, and more preferably 1 to 200 ppm, on a mass basis converted into platinum group metal atoms. If the amount of the catalyst is less than the above lower limit, it can not be possible to obtain the effect as a catalyst. In addition, even if the above upper limit is exceeded, the effect of the catalyst does not increase, and since it is not economical, it is not preferred.

[0101] [(H) component]

[0102] (H) component is a reaction control agent that suppresses the progress of a hydrosilylation reaction at room temperature, and functions to extend the shelf life and pot life. The reaction control agent can use a conventionally known reaction control agent used in an addition-curable silicone composition. As specific examples of the reaction control agent, acetylenic alcohols (for example, ethynylmethyldecylcarbinol, 1-ethynyl-1-cyclohexanol, 3,5-dimethyl-1-hexyn-3-ol), and the like acetylenic compounds; various nitrogen compounds such as tributylamine, tetramethylethylenediamine, benzotriazole, and the like; organophosphorus compounds such as triphenylphosphine; oxime compounds; organochlorine compounds; and the like can be listed.

[0103] The amount of the (H) component is 0.05 to 5.0 parts by mass, and preferably 0.1 to 1.0 parts by mass, relative to 100 parts by mass of the (A) component. If the amount of the reaction control agent is less than 0.05 parts by mass, it can be impossible to obtain a sufficient shelf life and pot life as desired, and in the case of more than 5.0 parts by mass, the curability of the silicone composition can be reduced. In addition, in order to improve the dispersibility in the silicone composition, the control agent can be used by being diluted with an organic (poly)siloxane, toluene, or the like.

[0104] [Other Components]

[0105] The silicone composition of the present application can contain a non-reactive organic (poly)siloxane such as methylpolysiloxane, or the like, in order to adjust the modulus of elasticity 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, or the like, can be contained as needed. In addition, a dye, a pigment, a flame retardant, an anti-settling agent, or a thixotropy improver, or the like, can be compounded as needed.

[0106] Next, a method for producing the thermally conductive silicone composition of the present application will be described, but is not limited to these. The method for producing the thermally conductive silicone composition of the present application has a step of producing a silicone composition containing the above (A) to (H) components.

[0107] [Production Step of Silicone Composition]

[0108] The method of producing the silicone composition of the present application is not particularly limited and can be carried out according to the conventional method of producing silicone grease compositions. For example, the components (A) to (J) described above, and other components as needed can be mixed by using a mixer such as a Trimix, a Twin Mix, a Planetary Mixer (all are registered trademarks of the mixing machine manufactured by Noguchi Seiki Kaisha Co., Ltd.), an Ultra Mixer (registered trademark of the mixing machine manufactured by Mizuho Industrial Co., Ltd.), a Hivis DisperMix (registered trademark of the mixing machine manufactured by Tokushu Kika Kogyo Co., Ltd.), and the like. In the case where the components (C-1) to (C-3) are used as the component (C), it is preferable to mix the components (C-1) to (C-3) with the components (A) and (B) in advance from the viewpoint of obtaining a uniform composition.

[0109] The absolute viscosity of the silicone composition of the present application measured at 25°C is preferably 3.0 to 800 Pa-s, more preferably 150 to 450 Pa-s. If the absolute viscosity is less than 3.0 Pa-s, the shape retention becomes difficult and the workability can be deteriorated. In addition, in the case where the absolute viscosity exceeds 800 Pa-s, the discharge becomes difficult and the workability can be deteriorated. The absolute viscosity described above can be obtained by adjusting the compounding of the components described above. In the present application, the absolute viscosity is the value measured at 25°C using a Malcom viscometer (with rotor A, at 10 rpm, shear rate 6 [1 / s]).

[0110] The thermal conductivity of the silicone composition of the present application measured at 25°C is preferably 4.0 W / m°C or more, more preferably 5.0 W / m°C or more, and further preferably 6.0 W / m°C or more. In the present application, the thermal conductivity is the value measured using a TPA-501 manufactured by Kyoto Electronics Manufacturing Co., Ltd.

[0111] In addition, the coating film thickness of the silicone composition described above obtained by using the following measurement method is preferably 100 μm or less, more preferably 75 μm or less, and further preferably 65 μm or less. By having such a property, for example, when applied between a heat dissipating member and a cooling member of a semiconductor device, a thin coating film can be formed, and by curing the silicone composition, a thin cured product layer can be obtained.

[0112] In the present application, the measurement method of the coating film thickness of the silicone composition described above is the value measured using the following method. A test piece was produced by applying a pressure of 0.1 MPa for 60 minutes at 25°C in a state where each composition was sandwiched between two circular aluminum plates (diameter 12.6 mm, thickness 1 mm) so as to have a thickness of 100 μm.

[0113] The thickness of the test piece was measured using a well-known micrometer, and the thickness of the composition was determined by subtracting the thickness of the aluminum plate, which was measured in advance.

[0114] [the cured product]

[0115] The silicone composition of the present application can be preferably used between a heat dissipating member such as an electronic component such as an LSI and a cooling member to transfer heat from the heat dissipating member to the cooling member to dissipate heat, and can be used in the same manner as the conventional heat conductive silicone grease. For example, the silicone composition of the present application can be cured by heat dissipation from the heat dissipating member such as an electronic component. Alternatively, the silicone composition of the present application can be actively heated and cured after being applied. Thus, a semiconductor device in which the cured product of the silicone composition of the present application is present between the heat dissipating member and the cooling member can be provided. The curing conditions when the silicone composition of the present application is heated and cured are not particularly limited, and are usually 80 to 200°C, preferably 100 to 180°C, for 30 minutes to 4 hours, preferably 30 minutes to 2 hours.

[0116] Further, from the viewpoint of improving adhesiveness and heat dissipation performance, it is preferable that the thickness of the layer of the cured product of the silicone composition interposed between the heat dissipating member and the cooling member be 100 μm or less, more preferably 75 μm or less, and further preferably 65 μm or less.

[0117] The thickness of the above-mentioned cured product layer can be adjusted by adjusting the thickness of the coating film of the above-mentioned silicone composition. Further, when the above-mentioned silicone composition is applied between the heat dissipating member and the cooling member, the heat dissipating member and the cooling member are pressed at a prescribed temperature and pressure, whereby the thickness of the coating film can be made thinner, and further improvement in heat dissipation performance while maintaining good adhesiveness is expected.

[0118] [tensile shear adhesive force]

[0119] The tensile shear adhesive force of the cured product of the silicone composition of the present application is preferably 0.05 to 3.0 MPa, and more preferably 0.1 to 2.0 MPa. The method for measuring the adhesive force is described in the Examples described later.

[0120] The silicone composition of the present application has high thermal conductivity, and good adhesiveness, and further can form a thin coating film, and thus can be particularly preferably used as a heat dissipation grease for a semiconductor device or the like of a high-quality equipment type.

[0121] Examples

[0122] Examples and Comparative Examples are shown below to explain the present application in more detail, and the present application is not limited by the following Examples. In the following, the kinematic viscosity is a value measured at 25°C using a U-type Ostwald viscometer (manufactured by Shibata Scientific Technology Co., Ltd.).

[0123] [(A) component]

[0124] A-1: dimethylpolysiloxane capped at both terminals with dimethylvinylsilyl groups, having a kinematic viscosity at 25°C of 600 mm 2 / s

[0125] A-2: dimethylpolysiloxane capped at both terminals with dimethylvinylsilyl groups, having a kinematic viscosity at 25°C of 400 mm 2 / s

[0126] [(B) component]

[0127] B-1: polyorganosiloxane having a hydrolyzable group represented by the following average formula

[0128] [Chemical 9]

[0129]

[0130] [(C) component]

[0131] C-1-1: round aluminum nitride powder having an average particle diameter of 19.6 μm (0.02 mass% of sieve residue with a 200 mesh metal screen, 0.9 mass% of comb / sieve residue with a 325 mesh metal screen)

[0132] C-1-2: round aluminum nitride powder having an average particle diameter of 22.6 μm (0.04 mass% of sieve residue with a 200 mesh metal screen, 0.01 mass% of comb / sieve residue with a 325 mesh metal screen)

[0133] C-1-3: round aluminum nitride powder having an average particle diameter of 15.6 μm (0.01 mass% of sieve residue with a 200 mesh metal screen, 0.70 mass% of comb / sieve residue with a 325 mesh metal screen)

[0134] C-1-4: round aluminum nitride powder having an average particle diameter of 10.6 μm (0.01 mass% of sieve residue with a 200 mesh metal screen, 0.01 mass% of comb / sieve residue with a 325 mesh metal screen)

[0135] C-1-5: round aluminum nitride powder having an average particle diameter of 20.9 μm (1.02 mass% of sieve residue with a 200 mesh metal screen, 8.76 mass% of comb / sieve residue with a 325 mesh metal screen)

[0136] C-2-1: round aluminum nitride powder having an average particle diameter of 6.6 μm (0.01 mass% of sieve residue with a 200 mesh metal screen, 0.01 mass% of comb / sieve residue with a 325 mesh metal screen)

[0137] C-2-2: Round aluminum nitride powder having an average particle diameter of 2.6 μm (0.01 mass% of sieve residue with 200 mesh metal net, 0.01 mass% of comb / sieve residue with 325 mesh metal net)

[0138] C-2-3: Spherical aluminum oxide powder having an average particle diameter of 3.6 μm (0.01 mass% of sieve residue with 200 mesh metal net, 0.01 mass% of comb / sieve residue with 325 mesh metal net)

[0139] C-3-1: Zinc oxide powder having an average particle diameter of 0.4 μm

[0140] C-3-2: Zinc oxide powder having an average particle diameter of 0.9 μm

[0141] C-3-3: Aluminum nitride powder having an average particle diameter of 0.7 μm

[0142] C-3-4: Aluminum oxide powder having an average particle diameter of 0.9 μm

[0143] [(D) Component]

[0144] D-1: Organic hydrogen polysiloxane represented by the following formula

[0145] [Chemical Formula 10]

[0146]

[0147] D-2: Organic hydrogen polysiloxane represented by the following formula

[0148] [Chemical Formula 11]

[0149]

[0150] D-3: Organic hydrogen polysiloxane represented by the following formula (comparative product)

[0151] [Chemical Formula 12]

[0152]

[0153] [(E) Component]

[0154] E-1: Organic hydrogen polysiloxane represented by the following formula

[0155] [Chemical Formula 13]

[0156]

[0157] E-2: Organic hydrogen polysiloxane represented by the following formula

[0158] [Chemical Formula 14]

[0159]

[0160] [(F) component]

[0161] F-1: a hydrolyzable organopolysiloxane represented by the following formula

[0162] [Chemical Formula 15]

[0163]

[0164] F-2: a hydrolyzable organopolysiloxane represented by the following formula [Chemical Formula 16]

[0165]

[0166] [(G) component]

[0167] G-1: a solution in which platinum-divinyltetramethyldisiloxane complex is dissolved in the same dimethylpolysiloxane as A-1 (platinum atom content: 1 mass%)

[0168] [(H) component]

[0169] H-1: a compound represented by the following formula

[0170] [Chemical Formula 17]

[0171]

[0172] [Examples 1 to 24, Comparative Examples 1 to 6]

[0173] (1) Preparation of silicone composition

[0174] The silicone compositions were prepared by compounding the above (A) to (H) components in the amounts shown in Tables 1 to 4 below, using the methods shown below. In Table 1, the mass of the (G) component is the mass of a solution in which platinum-divinyltetramethyldisiloxane complex is dissolved in dimethylpolysiloxane (platinum atom content: 1 mass%).

[0175] Into a 5 liter Planetary Mixer (manufactured by Nakamura Manufacturing Co., Ltd.), the (A), (B), (C), (F) components were added, and mixed at 170°C for 1 hour. After cooling to room temperature, the (D), (E), (G), (H) components were added, and mixed to make uniform, to prepare a silicone composition.

[0176] For each of the compositions obtained using the above method, the viscosity, thermal conductivity, elongation at break, and adhesive strength were measured according to the following methods. The results are shown in Tables 1 and 2.

[0177] [Viscosity]

[0178] The absolute viscosity of each composition was measured at 25°C using a Malcom viscometer (PC-1T type).

[0179] [Thermal conductivity]

[0180] Each composition was heated at 125°C for 60 minutes to cure, and a 6 mm thick sheet was produced. The thermal conductivity was measured using a TPS-2500 manufactured by Kyoto Electronics Manufacturing Co., Ltd.

[0181] [Measurement of thickness]

[0182] A test piece was produced by sandwiching each composition between two circular aluminum plates (diameter 12.6 mm, thickness 1 mm) so that the thickness was 100 μm, and applying a pressure of 0.1 MPa at 25°C for 60 minutes.

[0183] The thickness of the test piece was measured using a micrometer (manufactured by Mitutoyo Corporation), and the thickness of the composition was determined by subtracting the thickness of the aluminum plate, which was measured in advance.

[0184] [Measurement of tensile shear adhesive force]

[0185] A test piece was produced by sandwiching each composition between two aluminum (JIS H 4000A1050P) plates each having a thickness of 1.0 mm so that the thickness was 2.0 mm and the adhesive area was 25 mm x 10 mm, and heating at 125°C for 1 hour to cure the composition. The tensile shear adhesive force of the test piece was measured according to JIS K 6850.

[0186] [Table 1]

[0187]

[0188] [Table 2]

[0189]

[0190] [Table 3]

[0191]

[0192] [Table 4]

[0193]

[0194] From the results of Tables 1 to 4, the silicone compositions of Examples 1 to 24 satisfying the essential features of the present application have lower viscosity, higher thermal conductivity, and stronger adhesion compared to Comparative Examples 1 to 6. On the other hand, Comparative Example 1 having as little as 35 to 40 parts by mass of the component (C) relative to 100 parts by mass of the component (A) has low thermal conductivity. Comparative Example 2 having as much as 650 parts by mass of the component (B) relative to 100 parts by mass of the component (A) and Comparative Example 3 not containing the component (F) have low adhesion. In addition, the composition of Comparative Example 4 having much of the component (C) becomes non-uniform. In addition, Comparative Example 5 having n / (n+m) > 0.5 in the component (D) does not cure. In addition, Comparative Example 6 not containing the component (E) has low adhesion.

[0195] Therefore, the silicone composition of the present application can be confirmed to have good adhesion even if a large amount of thermally conductive filler is contained in the case of being used for firmly adhering a semiconductor chip to a heat sink.

Claims

1. A silicone composition comprising the following (A) to (D) components: (A) an organopolysiloxane having at least 2 aliphatic unsaturated hydrocarbon groups in one molecule, a kinematic viscosity at 25°C of 60 to 100,000 mm 2 / s: 100 parts by mass, (B) a hydrolyzable organopolysiloxane represented by the following general formula (1): 100 to 600 parts by mass, [Chem. 1] wherein R 1 independently of one another, alkyl having 1 to 6 carbon atoms, and r is an integer from 5 to 100, (C) a thermally conductive filler selected from at least one of metal oxides and metal nitrides: 4001 to 12000 parts by mass, (D) an organohydrogenpolysiloxane represented by the following general formula (2): 1.0 to 8.0 parts by mass, [Chem. 2] wherein n and m are each a number greater than 0, and are numbers satisfying 5.0 < n + m < 100, n / (n + m) < 0.5, R 2 independently of one another, an alkyl group having from 1 to 6 carbon atoms, (E) an organohydrogenpolysiloxane represented by the following general formula (3): 1.0 to 7.0 parts by mass, [Chem. 3] wherein o is an integer of 1 to 8, R 3 independently of one another a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or R 4 However, 2 or 3 of the groups represented by R 3 are hydrogen atoms, and the R 4 is a group selected from an epoxy group, an acryloyl group, a methacryloyl group, an ether group and a trialkoxysilyl group, which is bonded to the silicon atom via a carbon atom or an oxygen atom, (F) a hydrolyzable organopolysiloxane represented by the following general formula (4): 1 to 30 parts by mass, [Chem. 4] wherein p and q are each a number of 1.0 or more, and are numbers satisfying 5.0 < p + q < 100, R 5 independently of one another, an alkyl group having 1 to 6 carbon atoms, R 6 is an alkenyl group having 2 to 6 carbon atoms, (G) a platinum group metal catalyst: an effective amount (H) a reaction control agent: 0.05 to 5.0 parts by mass.

2. The silicone composition of claim 1, wherein, The (C) component comprises the following (C-1) to (C-3) components, (C-1) aluminum nitride particles having an average particle diameter of 10 μm or more and less than 30 μm, and a residual fraction of less than 1.0% by mass on a 200 mesh metal screen, (C-2) a metal oxide or a metal nitride having an average particle diameter of 1 μm or more and less than 10 μm, (C-3) a metal oxide or a metal nitride having an average particle diameter of 0.1 μm or more and less than 1 μm.

3. The silicone composition of claim 1, wherein, The thermal conductivity of the cured product is 4.0 W / m-K or more.

4. A semiconductor device in which a cured product of a silicone composition is interposed between a heat dissipating member and a cooling member, the layer of the cured product comprising a cured product of the silicone composition according to any one of claims 1 to 3, and the thickness of the layer is 100 μm or less.

5. The method for producing a silicone composition according to claim 2, comprising: A step of previously mixing the (C-1) to (C-3) components with the (A) component and the (B) component. A step of previously mixing the (C-1) to (C-3) components with the (A) component and the (B) component.

Images