WO2021241097A1 - Thermally conductive addition curing-type silicone composition - Google Patents

Abstract

The present invention is a thermally conductive addition curing-type silicone composition characterized by containing (A) an organopolysiloxane which has at least two aliphatic unsaturated hydrocarbon groups per molecule and has a kinematic viscosity at 25ºC of 60-100,000 mm2/s; (B) a silver powder at a quantity of 10-98 mass% relative to the overall composition; (C) a silver oxide powder at a quantity of 0.03-10 mass% relative to the overall composition; (D) an organohydrogenpolysiloxane having two or more silicon atom-bonded hydrogen atoms per molecule, at a quantity whereby the number of silicon atom-bonded hydrogen atoms is 0.5-5 relative to the total number of aliphatic unsaturated hydrocarbon groups in component (A); and (E) an effective amount of a platinum group metal catalyst. Due to this configuration, provided is a silver powder-containing thermally conductive addition curing-type silicone composition that exhibits excellent curing properties.

Description

Thermally conductive, curable silicone composition

The present invention relates to a thermally conductive addition-curable silicone composition.

As a problem common to electronic component packages and power modules, it is widely known that heat generation during operation and deterioration of performance due to it are widely known, and various heat dissipation technologies are used as means for solving this. In particular, a technique is generally used in which a cooling member is arranged in the vicinity of a heat generating portion so that the two are brought into close contact with each other, and then heat is efficiently removed from the cooling member to dissipate heat.

At that time, if there is a gap between the heat generating part and the cooling member, the heat transfer property is lowered due to the intervention of air having poor thermal conductivity, and the temperature of the heat generating member does not drop sufficiently. In order to prevent such air intervention and improve heat conduction, a heat radiating material having good thermal conductivity and following the surface of the member, for example, heat radiating grease or heat radiating sheet is used (for example, Patent Document 1). ~ 9).

As a heat countermeasure for actual electronic component packages and power modules, heat-dissipating grease that can be thinly compressed and has excellent penetration into the gap between the heat-generating part and the cooling member is suitable from the viewpoint of heat-dissipating performance. Furthermore, by heat-curing after compressing to the desired thickness, it is difficult for heat-dissipating grease to flow out (pumping out) due to expansion and contraction due to heat history that repeats heat generation and cooling of the heat-generating part, making it difficult for electronic component packages and power. Additive-curing thermal paste, which can increase the reliability of the module, is particularly useful (eg, Patent Document 10).

In recent years, in order to support new applications such as high output and high performance of electronic component packages and power modules, semiconductors for autonomous vehicles and IoT, there is a demand for higher heat conduction and higher reliability for heat dissipation materials. Silver powder is an example of a thermally conductive filler that can satisfy such a requirement. Silver has extremely high thermal conductivity by itself, and as a result of efficiently forming a heat transfer path by partially sintering the powders during heat curing, the thermal conductivity of the heat-dissipating material containing silver powder is improved. May be significantly improved.

On the other hand, it is known that the curability of the addition-curable silicone composition containing silver powder is lowered. If it is mounted on an electronic component package or a power module in a state where it is not sufficiently cured, reliability may decrease. Patent Document 11 discloses that the curability of an addition-curable silicone composition can be improved by blending a siloxane oligomer, an organopolysiloxane, and a silver powder surface-treated with a silicone resin. However, there is a problem that productivity is lowered due to the addition of a surface treatment step to the produced silver powder, and in order to more easily improve the curability of the addition-curable silicone composition containing the silver powder. Measures are required.

Japanese Unexamined Patent Publication No. 2002-327116 Japanese Unexamined Patent Publication No. 2004-130646 Japanese Unexamined Patent Publication No. 2009-234112 Japanese Unexamined Patent Publication No. 2009-209230 Japanese Unexamined Patent Publication No. 2010-09730 Japanese Unexamined Patent Publication No. 2008-031336 Japanese Unexamined Patent Publication No. 2007-177001 Japanese Unexamined Patent Publication No. 2008-260798 Japanese Unexamined Patent Publication No. 2009-209165 Japanese Unexamined Patent Publication No. 2016-053140 Japanese Unexamined Patent Publication No. 7-109501

Therefore, the present invention has been made in view of the above circumstances, and an object of the present invention is to provide a heat-conducting additive-curable silicone composition containing silver powder and having excellent curability.

In order to solve the above problems, the present invention
(A) Organopolysiloxane, which has at least two aliphatic unsaturated hydrocarbon groups in one molecule and has a kinematic viscosity of 60 to 100,000 mm ² / s at 25 ° C.
(B) Silver powder: an amount of 10 to 98% by mass with respect to the entire composition,
(C) Silver oxide powder: 0.03 to 10% by mass based on the total composition,
(D) Organohydrogenpolysiloxane having hydrogen atoms bonded to two or more silicon atoms in one molecule: Hydrogen bonded to silicon atoms with respect to the total number of aliphatic unsaturated hydrocarbon groups in the component (A). Amount in which the number of atoms is 0.5 to 5,
(E) Platinum group metal catalyst: Provided is a thermally conductive addition-curable silicone composition characterized by containing an effective amount.

If it is such a heat conductive addition curable silicone composition, it can be a heat conductive add curable silicone composition containing silver powder having excellent curability.

Further, in the present invention, it is preferable that the average particle size of the component (B) is 0.01 to 300 μm.

With such a thermally conductive addition-curable silicone composition, the obtained composition becomes uniform, the viscosity does not become too high, and the extensibility is excellent.

Further, in the present invention, it is preferable that the component (C) is silver (I) oxide.

With such a thermally conductive addition-curable silicone composition, the effect of the present invention can be further enhanced.

Further, in the present invention, an effective amount of one or more addition curing reaction control agents selected from the group consisting of (F) an acetylene compound, a nitrogen compound, an organic phosphorus compound, an oxime compound and an organic chloro compound may be further contained. preferable.

With such a heat conductive additive-curable silicone composition, a desired sufficient shelf life and pot life can be obtained, and there is no possibility that the curability of the silicone composition will be lowered.

The heat conductive add-curable silicone composition of the present invention has excellent heat curability while achieving high heat conductivity by blending silver powder. As a result, it is possible to achieve both excellent heat dissipation performance and high reliability by mounting it on an electronic component package or a power module.

As described above, there has been a demand for the development of a heat-conducting, heat-conducting, curable silicone composition containing silver powder, which has excellent curability.

As a result of diligent research to achieve the above object, the present inventors have obtained an aliphatic unsaturated hydrocarbon group-containing organopolysiloxane, silver powder, silver oxide powder, organohydrogenpolysiloxane, and platinum group metal catalyst. It has been found that a heat-conducting additive-curable silicone composition containing silver powder having excellent curability can be obtained by blending a specific amount, and the present invention has been made.

That is, the present invention comprises (A) an organopolysiloxane having at least two aliphatic unsaturated hydrocarbon groups in one molecule and having a kinematic viscosity of 60 to 100,000 mm ² / s at 25 ° C.
(B) Silver powder: an amount of 10 to 98% by mass with respect to the entire composition,
(C) Silver oxide powder: 0.03 to 10% by mass based on the total composition,
(D) Organohydrogenpolysiloxane having hydrogen atoms bonded to two or more silicon atoms in one molecule: Hydrogen bonded to silicon atoms with respect to the total number of aliphatic unsaturated hydrocarbon groups in the component (A). Amount in which the number of atoms is 0.5 to 5,
(E) Platinum group metal catalyst: A thermally conductive addition-curable silicone composition comprising an effective amount.

Hereinafter, the present invention will be described in detail, but the present invention is not limited thereto.

Component (A) Component (A) has at least 2, preferably 2 to 100, more preferably 2 to 50 aliphatic unsaturated hydrocarbon groups in one molecule, and has kinematic viscosity at 25 ° C. Is an organopolysiloxane having a viscosity of 60 to 100,000 mm ^{2 / s.}

The aliphatic unsaturated hydrocarbon group is preferably a monovalent hydrocarbon group having an aliphatic unsaturated bond and having 2 to 8 carbon atoms, more preferably 2 to 6 carbon atoms, and more preferably an alkenyl group. .. For example, alkenyl groups such as a vinyl group, an allyl group, a propenyl group, an isopropenyl group, a butenyl group, a hexenyl group, a cyclohexenyl group, and an octenyl group can be mentioned. A vinyl group is particularly preferable. 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.

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

The organopolysiloxane has a kinematic viscosity at 25 ° C. of 60 to 100,000 mm ² / s, 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 deteriorate, ^{and if it exceeds 100,000 mm 2} / s, the extensibility of the silicone composition becomes poor.

In the present invention, the kinematic viscosity is a value at 25 ° C. measured by an Ubbelohde type Ostwald viscometer (hereinafter, the same applies).

The molecular structure of the organopolysiloxane is not particularly limited as long as it has the above-mentioned properties, and examples thereof include a linear structure, a branched chain structure, a partially branched structure, and a linear structure having a cyclic structure. .. In particular, it is preferable that the main chain consists of repeating diorganosiloxane units and has a linear structure in which both ends of the molecular chain are closed with a triorganosyloxy group. The organopolysiloxane having the linear structure may have a partially branched structure or a cyclic structure.
The blending amount of the component (A) is preferably 1.5 to 90% by mass, more preferably 2 to 20% by mass, based on the entire composition. If it is 90% by mass or less, the thermal conductivity is excellent, and if it is 1.5% by mass or more, there is no risk of deterioration in workability.

The organopolysiloxane can be used alone or in combination of two or more.

Component (B) Component (B) is silver powder. The method for producing the silver powder is not particularly limited, and examples thereof include an electrolysis method, a pulverization method, a heat treatment method, an atomizing method, and a reduction method. The shape thereof is not particularly limited, such as flake-shaped, spherical, granular, indefinite-shaped, dendritic-shaped, and needle-shaped.
If the average particle size of the component (B) is 0.01 μm or more, the viscosity of the obtained composition does not become too high and the extensibility is excellent, and if it is 300 μm or less, the obtained composition becomes uniform. Therefore, a range of 0.01 to 300 μm, preferably a range of 0.1 to 100 μm, and more preferably a range of 1 to 50 μm is preferable. The average particle size can be obtained, for example, as a volume-based average value (or median diameter) in the particle size distribution measurement by a laser light diffraction method.

Further, the component (B) can be used alone or in combination of two or more, and the ratio thereof is not particularly limited and is arbitrary.

The blending amount of the component (B) is 10 to 98% by mass, preferably 70 to 97% by mass, and more preferably 80 to 95% by mass with respect to the entire composition. If it is more than 98% by mass, the viscosity of the composition may be significantly increased and the workability may be significantly lowered, and if it is less than 10% by mass, the thermal conductivity is poor.

Component (C) Component (C) is a silver oxide powder and acts as a co-catalyst for improving the curability of the thermally conductive additive-curable silicone composition obtained in the present invention. Silver oxide contains silver (I) oxide and silver monoxide depending on the difference in the number of oxidations of silver atoms, but it is preferable to use silver (I) oxide from the viewpoint of chemical stability and availability.

The blending amount of the component (C) is 0.03 to 10% by mass with respect to the entire composition, preferably 0.05 to 5 parts by mass. If the blending amount is less than 0.03% by mass, the effect of contributing to the improvement of the curability of the thermally conductive addition-curable silicone composition is poor, and even if it exceeds 10% by mass, the co-catalyst effect does not increase, which is uneconomical. Therefore, it is not preferable.

Component (D) The component (D) is an organohydrogenpoly having two or more hydrogen atoms (SiH groups) bonded to silicon atoms in one molecule, particularly preferably 2 to 100, and even more preferably 2 to 50. It is a siloxane. The organohydrogenpolysiloxane is capable of forming a crosslinked structure by an addition reaction of a SiH group in the molecule with an aliphatic unsaturated hydrocarbon group contained in the above-mentioned component (A) in the presence of a platinum group metal catalyst. All you need is.

The molecular structure of the organohydrogenpolysiloxane is not particularly limited as long as it has the above-mentioned properties, and the organohydrogenpolysiloxane has a linear structure, a branched chain structure, a cyclic structure, a partially branched structure, or a linear structure having a partially branched structure. The structure and the like can be mentioned. A linear structure or a cyclic structure is preferable.

The organohydrogenpolysiloxane has a kinematic viscosity at 25 ° C. of preferably 1 to 1,000 mm ² / s, more preferably 10 to 300 mm ² / s. If the kinematic viscosity is 1 mm ² / s or more, the physical properties of the silicone composition may not be deteriorated ^{, and if it is 1,000 mm 2} / s or less, the extensibility of the silicone composition may be poor. There is no.

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

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

Regarding the blending amount of the organohydrogenpolysiloxane of the component (D), the number of SiH groups in the component (D) is 0.5 to 5 with respect to the total number of aliphatic unsaturated hydrocarbon groups in the component (A). The amount is preferably 0.7 to 4.5, more preferably 1 to 4. If the amount of the component (D) is less than the above lower limit, the addition reaction does not proceed sufficiently and the crosslinking becomes insufficient. Further, if the value exceeds the above upper limit, the crosslinked structure may become non-uniform or the storage stability of the composition may be significantly deteriorated.

Component (E) Component (E) is a platinum group metal catalyst and functions to promote the addition reaction of the above-mentioned components. As the platinum group metal catalyst, conventionally known ones used for the addition reaction can be used. For example, platinum-based, palladium-based, and rhodium-based catalysts can be mentioned, but platinum or a platinum compound, which is relatively easily available, is preferable. For example, elemental platinum, platinum black, platinum chloride acid, platinum-olefin complex, platinum-alcohol complex, platinum coordination compound and the like can be mentioned. The platinum group metal catalyst may be used alone or in combination of two or more.

The blending amount of the component (E) may be an effective amount as a catalyst, that is, an effective amount necessary for promoting the addition reaction and curing the thermally conductive addition-curable silicone composition of the present invention. It is preferably 0.1 to 500 ppm, more preferably 1 to 200 ppm, still more preferably 10 to 100 ppm based on the mass in terms of platinum group metal atoms with respect to the entire composition. If the amount of the catalyst is equal to or more than the above lower limit, the effect as a catalyst can be sufficiently obtained. Moreover, it is economical if it is less than the above upper limit.

In addition to the above components, the following optional components can be further added to the thermally conductive addition-curable silicone composition of the present invention, if necessary.

Component (F) Component (F) is a reaction control agent that suppresses the progress of the hydrosilylation reaction at room temperature, and can be added to prolong the shelf life and pot life. As the reaction control agent, a conventionally known reaction control agent used in the addition-curable silicone composition can be used. This includes, for example, acetylene compounds such as acetylene alcohols (eg, ethynylmethyldecylcarbinol, 1-ethynyl-1-cyclohexanol, 3,5-dimethyl-1-hexin-3-ol), tributylamine, tetra. Examples thereof include various nitrogen compounds such as methylethylenediamine and benzotriazole, organic phosphorus compounds such as triphenylphosphine, oxime compounds, and organic chloro compounds.

When the component (F) is blended, the blending amount is preferably 0.05 to 5 parts by mass, more preferably 0.1 to 2 parts by mass with respect to 100 parts by mass of the component (A). If the amount of the reaction control agent is 0.05 parts by mass or more, the desired sufficient shelf life and pot life can be obtained, and if it is 5 parts by mass or less, the curability of the silicone composition may decrease. There is no.

Further, the reaction control agent may be diluted with organo (poly) siloxane, toluene or the like and used in order to improve the dispersibility in the silicone composition.

Other Ingredients The thermally conductive addition-curable silicone composition of the present invention may contain a non-reactive organo (poly) siloxane such as methylpolysiloxane in order to adjust the strength and viscosity of the composition. .. Further, one or more conventionally known heat conductive fillers other than silver may be used in combination. Further, a hydrolyzable organopolysiloxane, various modified silicones, and a hydrolyzable organosilane may be blended for the purpose of improving the filling property of the heat conductive filler and for imparting adhesiveness to the composition. Further, a solvent for adjusting the viscosity of the composition may be added. Further, in order to prevent deterioration of the silicone composition, a conventionally known antioxidant such as 2,6-di-tert-butyl-4-methylphenol may be contained, if necessary. Further, a dye, a pigment, a flame retardant, a sedimentation inhibitor, a thixo property improving agent and the like can be blended as needed.

Step for Producing Silicone Composition A method for producing a silicone composition in the present invention will be described. The method for producing the silicone composition in the present invention is not particularly limited, but the silicone composition contains the above-mentioned components (A) to (D), and if necessary, the component (E) and other components. Has a step of making.

The above-mentioned components (A) to (D), and if necessary, the component (E) and other components are used, for example, Trimix, Twinmix, Planetary Mixer (all are registered trademarks of Inoue Seisakusho Co., Ltd. mixer). , Ultramixer (registered trademark of Mizuho Kogyo Co., Ltd. mixer), Hibismix (registered trademark of Primix Co., Ltd. mixer), etc., usually at 25 ° C. for 3 minutes to 24 hours, preferably. Is a method of mixing for 5 minutes to 12 hours, particularly preferably 10 minutes to 6 hours. Further, degassing may be performed at the time of mixing, or the mixture may be mixed while heating in the range of 40 to 170 ° C.

In the present invention, it is preferable to mix the components (A) and (B) in advance at 25 ° C., and then mix the components (C), (D) and (E) at 25 ° C., for the silicone composition. It is preferable from the viewpoint of exhibiting thermal conductivity and curability. When the component (F), which is an optional component, is blended, the components (A) and (B) are mixed in advance, the component (F) is mixed, and then the components (C), (D) and (E) are mixed. Is preferably mixed.

The thermally conductive addition-curable silicone composition of the present invention has an absolute viscosity measured at 25 ° C., preferably 10 to 1,000 Pa · s, more preferably 20 to 700 Pa · s, still more preferably 40 to 600 Pa · s.・ S. When the absolute viscosity is 10 Pa · s or more, the shape can be easily maintained, the silver powder does not settle, and the workability does not deteriorate. Further, when the absolute viscosity is 1,000 Pa · s or less, there is no possibility that workability is deteriorated, such as easy ejection and coating. The absolute viscosity can be obtained by adjusting the blending amount of each of the above-mentioned components. The absolute viscosity can be measured at 25 ° C. using, for example, a Malcolm viscometer (type PC-1T).

Further, the heat conductive addition-curable silicone composition of the present invention usually has a thermal conductivity of 0.5 to 20 W / m · K. The thermal conductivity can be derived from, for example, the following equation.
(Thickness of silicone composition [μm]) ÷ (Thermal resistance value of silicone composition [mm ² · K / W])

The curing conditions for heat-curing the heat-conducting additive-curable silicone composition of the present invention are not particularly limited, but are usually 80 to 200 ° C., preferably 100 to 180 ° C. for 15 minutes to 4 hours. It is preferably 30 minutes to 2 hours.

Hereinafter, the present invention will be described in more detail by showing Examples and Comparative Examples, but the present invention is not limited to the following Examples. The kinematic viscosity shows the value at 25 ° C. by the Ubbelohde type Ostwald viscometer. Vi indicates a vinyl group. The average particle size is a volume-based average value in the particle size distribution measurement by the laser optical diffraction method.

First, the following components for preparing the thermally conductive addition-curable silicone composition of the present invention were prepared.

(A) Component A-1: Both ends are sealed with a dimethylvinylsilyl group, ^{and dimethylpolysiloxane A-2 having a kinematic viscosity at 25 ° C. of 600 mm 2} / s: Both ends are sealed with a dimethylvinylsilyl group, 25 ° C. Dimethylpolysiloxane with kinematic viscosity of 30,000 mm ^{2 / s}

(B) Component B-1: Flake-shaped silver powder with an average particle size of 3 μm B-2: Flake-shaped silver powder with an average particle size of 4 μm B-3: Flake-shaped silver powder with an average particle size of 10 μm B-4: Average particle size Flake-shaped silver powder B-5 with an average particle size of 15 μm: Spherical silver powder with an average particle size of 3 μm

(C) Ingredient C-1: Silver (I) oxide powder (manufactured by Wako Pure Chemical Industries, Ltd., standard content 99.0 +%)

(D) Component D-1: Methylhydrogendimethylpolysiloxane represented by the following formula (1) (kinematic viscosity at 25 ° C. = 100 mm ² / s)

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

(F) Component F-1: 1-ethynyl-1-cyclohexanol represented by the following formula (2)

[Examples 1 to 7, Comparative Examples 1 to 5]
Preparation of Thermally Conductive Additive-Curing Silicone Composition The above-mentioned components (A) to (F) are blended in the amounts shown in Tables 1 and 2 below by the methods shown below to form a thermally conductive addition-curable silicone composition. Was prepared. In the table, the mass of the component (E) is the mass of a solution (platinum atom content: 1% by mass) in which a platinum-divinyltetramethyldisiloxane complex is dissolved in dimethylpolysiloxane. Further, SiH / SiVi is the ratio of the total number of SiH groups in the component (D) to the total number of alkenyl groups in the component (A).
The components (A) and (B) were added to a 0.3 liter hibis mix (manufactured by Primix Corporation), and the mixture was mixed at 25 ° C. for 1 hour. Next, the components (F), (E), (D), and (C) were added and mixed so as to be uniform to prepare a silicone composition.
For each silicone composition obtained by the above method, the absolute viscosity and thermal conductivity were measured according to the following methods, and the state of the cured product was confirmed. The results are shown in Tables 1 and 2.

[Absolute viscosity]
The absolute viscosity of each silicone composition was measured at 25 ° C. using a Malcolm viscometer (type PC-1T) (10 rpm with rotor A, slip speed 6 [1 / s]).

[Thermal conductivity]
Each silicone composition is sandwiched between two aluminum plates of φ12.7 mm and heat-cured at 150 ° C. for 1 hour under a pressure of 0.14 MPa to prepare a test piece for thermal resistance measurement, and the silicone composition is prepared. The thermal resistance of was measured. Further, the thickness of the test piece was measured with a microgauge, and the thickness of the silicone composition was calculated from the difference from the thickness of the aluminum plate measured in advance. Then, the thermal conductivity of the silicone composition was derived from the following formula.
(Thickness of silicone composition [μm]) ÷ (Thermal resistance value of silicone composition [mm ² · K / W])
A nanoflash (manufactured by Nitsche, LFA447) was used for the thermal resistance measurement.

[Condition of cured product]
Each uncured silicone composition was applied between two parallel plates having a diameter of 2.5 cm to a thickness of 2 mm. After heating the coated plate from 25 ° C to 150 ° C at 5 ° C / min,
After holding at 150 ° C. for 1 hour, the mixture was cooled to 25 ° C., and it was determined by touch whether it was a rubber-like cured / uncured and liquid state. A viscoelasticity measuring device (ARES-G2: manufactured by TA Instruments Japan Co., Ltd.) was used to prepare the cured product.

From the results of Tables 1 and 2, the heat-conducting additive-curable silicone compositions of Examples 1 to 7 satisfying the requirements of the present invention have high thermal conductivity and a rubber-like cured product can be obtained after heat-curing. You can see that. That is, high reliability can be obtained when mounting an electronic component package or a power module.

On the other hand, the silicone compositions of Comparative Examples 1 to 3 containing no component (C) (silver oxide powder), Comparative Example 4 in which the content of the component (C) is too small, and Comparative Example 5 in which the value of SiH / SiVi is too small. As for the product, a rubber-like cured product cannot be obtained after heat curing and remains in a liquid state. That is, there is a risk that the reliability when mounting the electronic component package or the power module will decrease.

Therefore, the heat conductive addition-curable silicone composition of the present invention achieves high heat conductivity by blending a large amount of silver powder, and has good heat curability by containing a specific amount of silver oxide powder. .. Since it has such characteristics, it can be particularly preferably used as a thermal paste used for electronic component packages and power modules that require high reliability.

The present invention is not limited to the above embodiment. The above-described embodiment is an example, and any of the above-described embodiments having substantially the same configuration as the technical idea described in the claims of the present invention and having the same effect and effect is the present invention. Is included in the technical scope of.

Claims (4)

(A) Organopolysiloxane, which has at least two aliphatic unsaturated hydrocarbon groups in one molecule and has a kinematic viscosity of 60 to 100,000 mm ² / s at 25 ° C.
(B) Silver powder: an amount of 10 to 98% by mass with respect to the entire composition,
(C) Silver oxide powder: 0.03 to 10% by mass based on the total composition,
(D) Organohydrogenpolysiloxane having hydrogen atoms bonded to two or more silicon atoms in one molecule: Hydrogen bonded to silicon atoms with respect to the total number of aliphatic unsaturated hydrocarbon groups in the component (A). Amount in which the number of atoms is 0.5 to 5,
(E) Platinum group metal catalyst: A thermally conductive addition-curable silicone composition comprising an effective amount. The heat conductive addition-curable silicone composition according to claim 1, wherein the average particle size of the component (B) is 0.01 to 300 μm. The heat conductive addition-curable silicone composition according to claim 1 or 2, wherein the component (C) is silver (I) oxide. Further, claim 1 is characterized by containing an effective amount of one or more addition curing reaction control agents selected from the group consisting of (F) an acetylene compound, a nitrogen compound, an organic phosphorus compound, an oxime compound and an organic chloro compound. The heat conductive addition-curable silicone composition according to any one of claims 3.