JP7219728B2 - Thermally conductive silicone composition - Google Patents

Description

The present invention relates to thermally conductive silicone compositions.

It is widely known that electronic components such as LSIs and IC chips generate heat during use and the accompanying deterioration in performance, and various heat dissipation techniques are used as means for solving this problem. For example, by arranging a cooling member such as a heat sink near the heat generating part and bringing them into close contact, efficient heat transfer to the cooling member is promoted and the cooling member is cooled, thereby efficiently dissipating heat from the heat generating part. known to go to At that time, if there is a gap between the heat-generating member and the cooling member, heat transfer becomes inefficient due to the interposition of air with low thermal conductivity, and the temperature of the heat-generating member does not sufficiently decrease.

In order to prevent such a phenomenon, a heat dissipation sheet or heat dissipation grease is used as a heat dissipating material that has good thermal conductivity and conformability to the surface of the member in order to prevent air from intervening between the heat generating member and the cooling member. (Patent Documents 1 to 3). Among them, thermal grease exhibits high performance from the viewpoint of thermal resistance because it can be used with a reduced thickness when mounted. There is also a type of thermally conductive grease that is heat-cured after being sandwiched between members.

Thermal grease contains a large amount of filler to improve thermal conductivity, but as a result, the elongation after heat curing is reduced. There is concern that the material will lose its flexibility due to the reduction in elongation, and that it will not be able to follow the warpage during operation. If it becomes impossible to follow, a gap is generated between the member and the heat-dissipating grease, and the heat-dissipating performance deteriorates. In order to solve this problem, by blending a component containing an alkenyl group at the end of the molecular chain and a component containing an alkenyl group at the side chain and/or the end of the molecular chain, elongation after curing is high and warping during operation A thermally conductive silicone composition has been proposed that can follow. However, a composition with high elongation is very soft and lacks material strength, so there is a problem that it cannot withstand the expansion of volatile components generated by high temperature heating and voids are generated.

Japanese Patent No. 2938428 Japanese Patent No. 2938429 Japanese Patent No. 3952184

An object of the present invention is to provide a thermally conductive silicone composition that has high elongation, can follow warping, and does not generate voids after curing or after heating at high temperature.

In order to achieve the above objects, the present invention provides a thermally conductive silicone composition containing the following components (A), (B), (C) and (D).
(A) an organopolysiloxane having at least 6 alkenyl groups directly bonded to silicon atoms at the ends of the molecular chain in one molecule and having a kinematic viscosity at 25° C. of 100 to 100,000 mm ² /s;
(B) at least one thermally conductive filler selected from the group consisting of metals, metal oxides, metal hydroxides, metal nitrides, metal carbides, and carbon allotropes: 10 to 95 mass% of the total composition the amount that becomes
(C) Organohydrogenpolysiloxane having two or more silicon-bonded hydrogen atoms (Si—H groups) in one molecule: {number of Si—H groups in component (C)}/(in composition number of alkenyl groups) is 0.5 to 1.5,
(D) platinum group metal catalyst: effective amount

Such a thermally conductive silicone composition has high elongation, can follow warpage, and does not generate voids after curing and after heating at a high temperature.

（式中、Ｒ^１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Ｒ^１は同一であっても異なっていてもよい。またｍは５～１００の整数を示す。）
を含むものであってもよい。 Furthermore, the thermally conductive silicone composition of the present invention comprises (E) a hydrolyzable organopolysiloxane represented by the following general formula (1): 0.1 to 20% by mass of the entire composition;

(In the formula, R ¹ represents an optionally substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, each R ¹ may be the same or different, and m is 5 Indicates an integer of ~100.)
may include.

By including component (E), the viscosity of the thermally conductive silicone composition of the present invention can be lowered and adjusted, and furthermore, component (B) can be highly filled.

Furthermore, the thermally conductive silicone composition of the present invention (F) has at least one alkenyl group directly attached to a silicon atom at the end of the molecular chain in each molecule, excluding component (A), at 25°C. with a kinematic viscosity of 100 to 100,000 mm ² /s: up to 90% by weight based on the total organopolysiloxane containing alkenyl groups in the composition.

Furthermore, the thermally conductive silicone composition of the present invention has (G) at least 3 alkenyl groups in the side chain and/or the end of the molecular chain in one molecule, excluding the above components (A) and (F). Organopolysiloxane having a kinematic viscosity at 25° C. of 100 to 100,000 mm ² /s: an amount up to 50% by weight based on the total organopolysiloxane containing alkenyl groups in the composition, good too.

By containing such components (F) and (G), the hardness of the cured product of the thermally conductive silicone composition of the present invention can be adjusted.

Also, the component (B) is preferably aluminum powder and/or zinc oxide powder.

Such a component (B) is preferred from the viewpoint of thermal conductivity and availability.

Further, the thermally conductive silicone composition of the present invention comprises (H) a reaction controller selected from acetylene compounds, nitrogen compounds, organophosphorus compounds, oxime compounds, and organochloro compounds: It may contain an amount of 0.1% by mass to 5% by mass with respect to the total polysiloxane.

By including the component (H), the catalytic activity of the component (D) is suppressed, that is, by suppressing the progress of the hydrosilylation reaction at room temperature. Extends shelf life and pot life.

The thermally conductive silicone composition was heated and cured at 150° C. for 60 minutes to prepare a 2 mm thick sheet. Preferably.

With such a thermally conductive silicone composition of the present invention, delamination is less likely to occur during high-temperature storage, and the risk of deterioration in thermal resistance can be reduced.

The thermally conductive silicone composition was sandwiched between glass sheets, pressurized at room temperature for 15 minutes, heated at 150° C. for 60 minutes, cooled to room temperature, and heated at 260° C. for 5 minutes five times. preferably not.

With such a thermally conductive silicone composition, heat dissipation performance can be maintained even under the above conditions.

As described above, the thermally conductive silicone composition of the present invention has high elongation, can follow warpage, does not generate voids even after curing, and does not generate voids even after heating at high temperature. It becomes a flexible silicone composition.

As described above, there has been a demand for the development of a thermally conductive silicone composition that has high elongation, can follow warpage, and does not generate voids after curing or after being heated to a high temperature.

As a result of intensive studies to achieve the above object, the present inventors have developed a thermally conductive silicone composition that has high elongation, can follow warpage, and does not generate voids after curing and after heating at high temperatures.

More specifically, by blending a component containing six alkenyl groups at the ends of the molecular chains, it was found that voids do not occur after curing and after heating at high temperature while maintaining the softness of the material, and the present invention was completed. let me

The present invention is a thermally conductive silicone composition containing the following components (A), (B), (C) and (D).
(A) an organopolysiloxane having at least 6 alkenyl groups directly bonded to silicon atoms at the ends of the molecular chain in one molecule and having a kinematic viscosity at 25° C. of 100 to 100,000 mm ² /s;
(B) at least one thermally conductive filler selected from the group consisting of metals, metal oxides, metal hydroxides, metal nitrides, metal carbides, and carbon allotropes: 10 to 95 mass% of the total composition the amount that becomes
(C) Organohydrogenpolysiloxane having two or more silicon-bonded hydrogen atoms (Si—H groups) in one molecule: {number of Si—H groups in component (C)}/(in composition number of alkenyl groups) is 0.5 to 1.5,
(D) platinum group metal catalyst: effective amount

The thermally conductive silicone composition of the present invention will be described in more detail below, but the present invention is not limited thereto.
[(A) Component]
The organopolysiloxane of component (A) has at least 6 alkenyl groups directly linked to silicon atoms at the ends of the molecular chain in one molecule, and may be linear or branched. Mixtures of different viscosities are also possible. Examples of the alkenyl group include vinyl group, allyl group, 1-butenyl group, 1-hexenyl group and the like, but the vinyl group is preferred from the viewpoints of ease of synthesis and cost. The remaining organic groups bonded to the silicon atom include alkyl groups such as methyl group, ethyl group, propyl group, butyl group, hexyl group and dodecyl group; aryl groups such as phenyl group; Examples include aralkyl groups such as alkyl group, and substituted hydrocarbon groups such as chloromethyl group and 3,3,3-trifluoropropyl group. Among these, a methyl group is preferred from the viewpoints of ease of synthesis and cost. The alkenyl group directly bonded to the silicon atom is preferably present at the end of the main molecular chain of the organopolysiloxane. The kinematic viscosity of the component (A), organopolysiloxane, at 25° C. is in the range of 100 to 100,000 mm ² /s, preferably 500 to 100,000 mm ² /s. If the kinematic viscosity is outside the above range, the obtained composition may be inferior in fluidity, workability and strength of the cured product.

[(B) Component]
Component (B) is 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. As the thermally conductive filler having the thermal conductivity of component (B), one having a thermal conductivity of 10 W/mK or more is preferably used. This is because if the thermal conductivity of the thermally conductive filler is 10 W/mK or more, the thermal conductivity of the thermally conductive silicone composition itself increases. Such thermally conductive fillers include aluminum powder, copper powder, iron powder, nickel powder, gold powder, metallic silicon powder, aluminum nitride powder, boron nitride powder, alumina powder, diamond powder, carbon powder, indium powder, gallium powder. , zinc oxide powder and the like. Any filler having a capacity of 10 W/mK or more may be used, and one type or a combination of two or more types may be used.

Component (B) is preferably aluminum powder, alumina powder, or zinc oxide powder, more preferably aluminum powder and/or zinc oxide powder, from the viewpoint of thermal conductivity and availability.

The average particle size of component (B) is preferably in the range of 0.1 to 100 μm. If the average particle size is 0.1 μm or more, the resulting thermally conductive silicone composition will be grease-like and will have good spreadability. This is because there is little possibility that the thermal performance will deteriorate. In the present invention, the average particle size can be measured by Microtrac MT3300EX manufactured by Nikkiso Co., Ltd., and is the volume-based average particle size. The shape of component (B) may be irregular, spherical, or any other shape.

The filling amount of component (B) is in the range of 10 to 95% by mass, preferably 15 to 95% by mass, more preferably 15 to 93% by mass, based on the total composition. If the filling amount is less than the lower limit, the thermal conductivity of the composition will be low, and if it exceeds the upper limit, the viscosity of the composition will increase, resulting in poor extensibility.

[(C) Component]
The organohydrogenpolysiloxane of component (C) must have two or more silicon-bonded hydrogen atoms (Si—H groups) in one molecule in order to form a network by cross-linking. , may be linear or branched, or a mixture of two or more of these with different viscosities. The remaining organic groups bonded to the silicon atom include alkyl groups such as methyl group, ethyl group, propyl group, butyl group, hexyl group and dodecyl group; aryl groups such as phenyl group; Examples include aralkyl groups such as alkyl group, and substituted hydrocarbon groups such as chloromethyl group and 3,3,3-trifluoropropyl group. Among these, a methyl group is preferred from the viewpoints of ease of synthesis and cost.

The blending amount of component (C) is such that {number of Si—H groups in component (C)}/(number of alkenyl groups in composition) is 0.5 to 1.5, and 0.7. A range of ~1.3 is more preferred. If the amount of component (C) is less than the above lower limit, the composition will not be sufficiently reticulated and the grease will not harden sufficiently. .

[(D) Component]
Component (D) is a platinum group metal catalyst that promotes the addition reaction between the alkenyl groups in the composition containing component (A) and the Si—H groups of component (C). As the platinum group metal catalyst, conventionally known ones used for addition reactions can be used. For example, platinum-based, palladium-based, and rhodium-based catalysts can be used, but platinum or platinum compounds, which are relatively easily available, are preferred. Examples thereof include simple platinum, platinum black, chloroplatinic acid, platinum-olefin complexes, platinum-alcohol complexes, and platinum coordination compounds. The platinum-based catalyst may be used singly or in combination of two or more.

The amount of component (D) is 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. It is preferably from 0.1 to 500 ppm, more preferably from 1 to 200 ppm, based on the total mass of the component (organopolysiloxane) containing an alkenyl group, including the component (A), in terms of platinum group metal atoms. If the amount of the catalyst is at least the above lower limit, a sufficient catalytic effect can be obtained, and if it is at most the above upper limit, the catalytic effect can be obtained economically, which is preferable.

（式中、Ｒ^１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Ｒ^１は同一であっても異なっていてもよい。またｍは５～１００の整数を示す。） [(E) Component]
In order to reduce the viscosity of the composition, the thermally conductive silicone composition of the present invention may further contain a hydrolyzable organopolysiloxane represented by the following general formula (1) as component (E). Component (E) is used to treat the surface of the thermally conductive filler, and assists in increasing the filling of the filler.

(In the formula, R ¹ represents an optionally substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, each R ¹ may be the same or different, and m is 5 Indicates an integer of ~100.)

In the above formula, each R ¹ is independently an unsubstituted or substituted monovalent group containing no aliphatic unsaturated groups, preferably having 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, more preferably 1 to 3 carbon atoms. It is a hydrocarbon group. Examples include linear alkyl groups, branched alkyl groups, cyclic alkyl groups, aryl groups, aralkyl groups, and halogenated alkyl groups. Linear alkyl groups include, for example, methyl, ethyl, propyl, hexyl, octyl, and decyl groups. Branched chain alkyl groups include, for example, isopropyl, isobutyl, tert-butyl, and 2-ethylhexyl groups. Cyclic alkyl groups include, for example, a cyclopentyl group and a cyclohexyl group. Aryl groups include, for example, a phenyl group and a tolyl group. The aralkyl group includes, for example, 2-phenylethyl group, 2-methyl-2-phenylethyl group and the like. Halogenated alkyl groups include, for example, 3,3,3-trifluoropropyl, 2-(nonafluorobutyl)ethyl, and 2-(heptadecafluorooctyl)ethyl groups. Among them, R ¹ is preferably a methyl group or a phenyl group. m is an integer of 5-100, preferably an integer of 10-60. When the value of m is 5 or more, there is little possibility that oil bleeding from the silicone composition will become severe and reliability will deteriorate. Further, when the value of m is 100 or less, the possibility that the wettability of the filler is insufficient is small.

The amount of component (E) is preferably 0.1 to 20% by mass, more preferably 1 to 15% by mass, based on the total composition. If the amount of component (E) is at least the above lower limit, there is little risk of insufficient wettability being exhibited, and if the amount is below the above upper limit, there is little risk of severe bleeding from the composition.

[(F) Component]
In order to adjust the hardness of the cured product of the resulting composition, the thermally conductive silicone composition of the present invention further contains a silicon atom at the end of the molecular chain as component (F), excluding component (A). Organopolysiloxanes containing at least one alkenyl group directly linked to can be blended. The organopolysiloxane may be linear or branched, or a mixture of two or more of these with different viscosities. Examples of the alkenyl group include vinyl group, allyl group, 1-butenyl group, 1-hexenyl group and the like, but the vinyl group is preferred from the viewpoints of ease of synthesis and cost. The remaining organic groups bonded to the silicon atom include alkyl groups such as methyl group, ethyl group, propyl group, butyl group, hexyl group and dodecyl group; aryl groups such as phenyl group; Examples include aralkyl groups such as alkyl group, and substituted hydrocarbon groups such as chloromethyl group and 3,3,3-trifluoropropyl group. Among these, a methyl group is preferred from the viewpoints of ease of synthesis and cost. The alkenyl group directly bonded to the silicon atom is preferably present at the end of the main molecular chain of the organopolysiloxane. The number of alkenyl groups in component (F) is preferably two or more, more preferably two. Also, the kinematic viscosity at 25° C. is in the range of 100 to 100,000 mm ² /s, preferably 500 to 100,000 mm ² /s.

The amount of component (F) to be blended is preferably up to 90% by mass, preferably up to 85% by mass, more preferably 80% by mass, based on the total amount of organopolysiloxane containing alkenyl groups in the composition. % is good. If the component (F) is within the above range, there is little possibility that the crosslink density will be too low and the composition will not be sufficiently cured.

[(G) Component]
In order to adjust the hardness of the cured product of the thermally conductive silicone composition of the present invention, the component (G), excluding components (A) and (F), contains side chains of molecular chains in one molecule. and/or an organopolysiloxane having at least three terminal alkenyl groups. The organopolysiloxane may be linear or branched, or a mixture of two or more of these with different viscosities. Examples of the alkenyl group include vinyl group, allyl group, 1-butenyl group, 1-hexenyl group and the like, but the vinyl group is preferred from the viewpoints of ease of synthesis and cost. The remaining organic groups bonded to the silicon atom include alkyl groups such as methyl group, ethyl group, propyl group, butyl group, hexyl group and dodecyl group; aryl groups such as phenyl group; Examples include aralkyl groups such as alkyl group, and substituted hydrocarbon groups such as chloromethyl group and 3,3,3-trifluoropropyl group. Among these, a methyl group is preferred from the viewpoints of ease of synthesis and cost. The alkenyl group bonded to the silicon atom may be in the side chain or terminal of the molecular chain, but is preferably present in at least the side chain. Furthermore, it is preferable to have it on both the side chain and the end. Also, the kinematic viscosity at 25° C. is in the range of 100 to 100,000 mm ² /s, preferably 500 to 100,000 mm ² /s.

The amount of component (G) to be blended is at most 50% by mass, preferably up to 45% by mass, more preferably 40% by mass, based on the total amount of alkenyl group-containing organopolysiloxanes in the composition. % is good. If the component (G) is within the above range, there is little possibility that the crosslink density will become too high and the elongation will decrease.

[(H) Component]
The thermally conductive silicone composition of the present invention contains reaction control agents for the purpose of suppressing the catalytic activity of component (D), that is, to suppress the progress of the hydrosilylation reaction at room temperature and extend the shelf life and pot life. As an agent, the component (H) can be further contained. Conventionally known reaction control agents can be used, and acetylene compounds, various nitrogen compounds, organic phosphorus compounds, oxime compounds, organic chloro compounds, and the like can be used.

The amount of component (H) to be blended is 0.1% by mass or more relative to the total of alkenyl group-containing organopolysiloxanes in the composition (total of components (A), (F) and (G)). The range of 0.1 to 5% by mass is preferable because a sufficient shelf life and pot life can be obtained if the amount is sufficient, and the curing rate does not decrease if the amount is 5% by mass or less. These components (H) may be diluted with toluene or the like for better dispersibility in the thermally conductive silicone composition.

[Additive]
In addition to the above components (A) to (H), the thermally conductive silicone composition of the present invention contains 2,6-di-t-butyl-4-methyl to prevent deterioration of the addition-curable silicone composition. A conventionally known antioxidant such as phenol may be contained as necessary. Furthermore, adhesion aids, release agents, dyes, pigments, flame retardants (heat-resistant improvers), anti-settling agents, thixotropic improvers, etc. can be blended as necessary.

[Method for preparing thermally conductive silicone composition]
The method of preparing the thermally conductive silicone composition (grease) of the present invention is not particularly limited. (registered trademark of mixer manufactured by Co., Ltd.), Ultra Mixer (registered trademark of mixer manufactured by Mizuho Kogyo Co., Ltd.), Hivis Dispermix (registered trademark of mixer manufactured by Tokushu Kika Kogyo Co., Ltd.), etc. A method of mixing can be mentioned.

The thermally conductive silicone composition of the present invention may be mixed while being heated, and the heating conditions are not particularly limited. The temperature is preferably 50 to 200° C., and the time is usually 3 minutes to 24 hours, preferably 5 minutes to 12 hours, more preferably 10 minutes to 6 hours. Further, degassing may be performed during heating.

[Characteristics of Thermally Conductive Silicone Composition]
The thermally conductive silicone composition of the present invention thus obtained preferably has a viscosity measured at 25° C. of 100 to 1,000 Pa·s, preferably 150 to 800 Pa·s, more preferably 150 to 800 Pa·s. is 200 to 600 Pa·s. If the viscosity is equal to or higher than the lower limit of the above range, there is little possibility that workability will be deteriorated, such as sedimentation of the thermally conductive filler over time during storage. Further, when the thickness is equal to or less than the upper limit of the above range, there is little possibility that extensibility will be poor and workability will be deteriorated.

Thermally conductive silicone compositions of the present invention typically have a thermal conductivity of 0.5 to 10 W/mK.

The thermally conductive silicone composition of the present invention is, for example, heated and cured at 150° C. for 60 minutes to prepare a sheet with a thickness of 2 mm. The subsequent elongation at break is preferably 80% or more, more preferably 85% or more, and still more preferably 90% or more. When the elongation at break is at least the above lower limit, peeling is less likely to occur during high-temperature storage, and the risk of deterioration in heat resistance is small.

Alternatively, the thermally conductive silicone composition of the present invention may be sandwiched between glass plates, pressurized at room temperature for 15 minutes, heated at 150° C. for 60 minutes, cooled to room temperature, and then heated at 260° C. for 5 minutes. It is preferred to have no voids after 5 iterations.
With such a thermally conductive silicone composition, heat dissipation performance can be maintained even under the above conditions.

EXAMPLES 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 these.

A test regarding the effect of the present invention was conducted as follows.

[viscosity]
The absolute viscosity of each thermally conductive silicone composition was measured at 25° C. using a Malcolm viscometer (type PC-1TL).

[Thermal conductivity]
Each thermally conductive silicone composition was poured into a mold with a thickness of 3 cm, covered with plastic wrap for kitchen use, and measured using Model QTM-500 manufactured by Kyoto Electronics Industry Co., Ltd.

[Thermal resistance measurement]
Each thermally conductive silicone composition was sandwiched between a 15 mm × 15 mm × 1 mmt Si chip and a 15 mm × 15 mm × 1 mmt Ni plate, and the thermally conductive silicone composition was cured by heating in an oven at 150°C for 60 minutes. A test piece for resistance measurement was produced. After that, the test piece was allowed to stand at 150° C. for 1000 hours to observe changes in thermal resistance. In addition, this thermal resistance measurement was performed by nanoflash (LFA447 manufactured by Nitschei).

[Elongation at break]
Each thermally conductive silicone composition was cured by heating at 150° C. for 60 minutes to prepare a 2 mm thick sheet, which was shaped into a No. 2 dumbbell according to JIS K6251 and measured for elongation at break. The elongation at break was measured by AGS-X (manufactured by Shimadzu Corporation).

[Void test]
Each thermally conductive silicone composition was sandwiched between glass plates and left at room temperature for 15 minutes while being pressurized. After that, the thermally conductive silicone composition was cured by heating in an oven at 150°C for 60 minutes, removed from the oven and cooled to room temperature. . Furthermore, after repeating the cycle of placing the test piece in an oven at 260° C., leaving it for 5 minutes, taking it out and cooling it, the presence or absence of voids was visually confirmed.

The following components were prepared to form the thermally conductive silicone composition of the present invention. The kinematic viscosity indicates the value at 25° C. measured by an Ubbelohde-type Ostwald viscometer.

(A) Component A-1: Dimethylpolysiloxane having both ends capped with trivinylsilyl groups and a kinematic viscosity at 25°C of 1,500 mm ² /s A-2: Both ends capped with trivinylsilyl groups, Dimethylpolysiloxane having a kinematic viscosity of 5,000 mm ² /s at 25°C

(B) Component B-1: Aluminum powder in which aluminum powder having an average particle size of 20 μm and aluminum powder having an average particle size of 2 μm were previously mixed at a mass ratio of 60:40 B-2: Zinc oxide powder having an average particle size of 1.0 μm

Ｃ－２：

Ｃ－３：

Component (C) Organohydrogenpolysiloxane C-1 represented by the following formula:

C-2:

C-3:

(D) Component D-1: D-1 solution of platinum-divinyltetramethyldisiloxane complex containing 1% platinum atom

ここで、ｍは３０である。 (E) Component Organopolysiloxane E-1 represented by the following formula:

where m is 30.

(F) Component F-1: Dimethylpolysiloxane having both ends capped with dimethylvinylsilyl groups and a kinematic viscosity at 25°C of 600 mm ² /s F-2: Both ends capped with dimethylvinylsilyl groups at 25°C Dimethylpolysiloxane having a kinematic viscosity of 30,000 mm ² /s at

(G) Component G-1: Dimethylpolysiloxane having 8 methylvinylsilyl groups in the molecular chain and a kinematic viscosity at 25°C of 700 mm ² /s G-2: 15 methylvinylsilyl groups in the molecular chain dimethylvinylsilyl group at both ends and having a kinematic viscosity of 800 mm ² /s at 25° C. G-3: having one methylvinylsilyl group in the molecular chain and dimethylvinylsilyl at both ends Dimethylpolysiloxane with a kinematic viscosity of 30,000 mm ² /s at 25° C. blocked with groups

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

Heat resistance improver:

Examples 1-6 and Comparative Examples 1-6 were obtained by blending the components (A) to (H) and the heat resistance improver as follows.
Specifically, components (A), (B), (E), (F) and (G) were added to a 5-liter planetary mixer (manufactured by Inoue Seisakusho Co., Ltd.) and mixed at 170° C. for 1 hour. After cooling to room temperature, components (H), (D) and (C) and a heat resistance improver were added and mixed uniformly to prepare each thermally conductive silicone composition.

From the results in Tables 1 and 2, the thermally conductive silicone compositions of Examples 1 to 6, which satisfy the requirements of the present invention, exhibit high elongation and do not generate voids after heating at high temperatures.
On the other hand, in Comparative Examples 1 to 3, which do not contain component (A), high elongation and suppression of voids during high-temperature heating cannot be achieved at the same time. Also, in Comparative Example 4, the content of the component (B) was too large, so that it did not become grease-like. Furthermore, in Comparative Examples 5 and 6, when the ratio of {number of Si—H groups in component (C)}/(number of alkenyl groups in the composition) is too low, the composition does not sufficiently cure, and the ratio is too high. It becomes too hard and elongation becomes low.
Therefore, it was found that the thermally conductive silicone composition of the present invention can achieve both high elongation and suppression of voids after high-temperature heating.

Since the thermally conductive silicone composition of the present invention has high elongation, it is possible to follow the warp of the base material, and furthermore, voids do not occur even after heating at high temperature, so electronic parts that generate heat during use. It can be particularly suitably used as a heat-dissipating grease used for removing heat from the heat.

It should be noted that the present invention is not limited to the above embodiments. The above-described embodiment is an example, and any device having substantially the same configuration as the technical idea described in the claims of the present invention and exhibiting the same effects is the present invention. included in the technical scope of

Claims (8)

A thermally conductive silicone composition containing the following components (A), (B), (C) and (D).
(A) an organopolysiloxane having at least 6 alkenyl groups directly bonded to silicon atoms at the ends of the molecular chain in one molecule and having a kinematic viscosity at 25° C. of 100 to 100,000 mm ² /s;
(B) at least one thermally conductive filler selected from the group consisting of metals, metal oxides, metal hydroxides, metal nitrides, metal carbides, and carbon allotropes: 10 to 95 mass% of the total composition the amount that becomes
(C) Organohydrogenpolysiloxane having two or more silicon-bonded hydrogen atoms (Si—H groups) in one molecule: {number of Si—H groups in component (C)}/(in composition number of alkenyl groups) is 0.5 to 1.5,
(D) platinum group metal catalyst: effective amount (E) a hydrolyzable organopolysiloxane represented by the following general formula (1): 0.1 to 20% by mass of the total composition;

(In the formula, R ¹ represents an optionally substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, each R ¹ may be the same or different, and m is 5 Indicates an integer of ~100.)
The thermally conductive silicone composition according to claim 1, comprising: (F) Except for the above component (A), each molecule has at least one alkenyl group directly bonded to a silicon atom at the end of the molecular chain, and has a kinematic viscosity at 25°C of 100 to 100,000 mm ² /s Organopolysiloxane: A thermally conductive silicone composition according to Claim 1 or 2, characterized in that it contains up to 90% by weight of the total alkenyl group-containing organopolysiloxane in the composition. Furthermore, (G) excluding the above components (A) and (F), each molecule has at least 3 alkenyl groups on the side chain and/or the end of the molecular chain, and has a kinematic viscosity at 25 ° C. of 100 to 100 ,000 mm ² /s of organopolysiloxane: an amount of up to 50% by weight relative to the total of organopolysiloxanes containing alkenyl groups in the composition. The thermally conductive silicone composition according to Item. 5. The thermally conductive silicone composition according to any one of claims 1 to 4, wherein said component (B) is aluminum powder and/or zinc oxide powder. (H) a reaction controller selected from acetylene compounds, nitrogen compounds, organophosphorus compounds, oxime compounds, and organochloro compounds: 0.1 mass relative to the total amount of organopolysiloxane containing alkenyl groups in the composition % to 5% by weight of the thermally conductive silicone composition according to any one of claims 1 to 5. The thermally conductive silicone composition is heat-cured at 150° C. for 60 minutes to prepare a sheet with a thickness of 2 mm, and the sheet is shaped into a No. 2 dumbbell according to JIS K6251 and measured to have an elongation of 80% or more. The thermally conductive silicone composition according to any one of claims 1 to 6, characterized by The thermally conductive silicone composition was sandwiched between glass sheets, pressurized at room temperature for 15 minutes, heated at 150° C. for 60 minutes, cooled to room temperature, and heated at 260° C. for 5 minutes five times. The thermally conductive silicone composition according to any one of claims 1 to 7, characterized in that it does not have