JP2016216523A - Composition for thermal conducive grease, thermal conductive grease and heat dissipating member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition suitable for thermal conductive grease having excellent cold thermal shock resistance and small heat resistance.SOLUTION: In a first embodiment, a composition for thermal conductive grease is provided that contains (A) to (E) components. (A) silicone containing vinyl groups at both terminals and having a mass average molecular weight of 10,000 to 800,000 of 2.5 to 15 mass%. (B) silicone containing no vinyl group in a molecule and containing average 5 to 10 hydrosilyl groups in the molecule and having mass average molecular weight of 2000 to 10000 of 0.005 to 0.1 mass%. (C) silicone containing vinyl groups at both terminals and average 1 to 4 hydrosilyl group in the molecule and having mass average molecular weight of 10000 to 40000 of 1 to 10 mass%. (D) a silane coupling agent having a reactive double bond of 0.1 to 0.6 mass%. (E) a thermal conductive filler. In a second embodiment, a composition for thermal conductive grease is provided which is identical to the composition for thermal conductive grease described in the first embodiment except that the thermal conductive filler (E) is composed of one or more kind of component selected from silica, alumina, boron nitride, aluminum nitride and zinc oxide.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a thermally conductive grease composition, a thermally conductive grease, and a heat dissipation member.

  As heat generating electronic components are miniaturized and output is increased, the amount of heat per unit area generated from these electronic components has become very large. A metal heat sink or housing is used for cooling, and a heat dissipating material is used to efficiently transfer heat from electronic components to a cooling unit such as a heat sink or housing. As a reason for using this heat radiating material, when an electronic component and a heat sink or the like are brought into contact with each other as they are, microscopically, air is present at the interface, which hinders heat conduction. Therefore, heat can be efficiently transferred by allowing the heat dissipating material to exist between the electronic component and the heat sink instead of the air present at the interface.

  In addition, the heat radiation material continues to receive a thermal shock of several hundred degrees C. every time the electronic component is used, such as from minus tens of degrees Celsius depending on the use environment of the electronic device before operation of the electronic parts and high temperature during operation. In order to prevent the electronic components from failing for a long period of time, it is necessary to continue cooling the electronic components that generate heat, and the heat dissipation characteristics of the heat dissipation material should not be deteriorated.

  As a heat dissipation material, a heat conductive sheet made of a cured product obtained by filling a high molecular weight silicone or low molecular weight silicone with a heat conductive powder, a soft silicone such as low molecular weight silicone is filled with the heat conductive powder, and has flexibility. There are a thermally conductive pad made of a cured product, a fluid grease in which liquid silicone is filled with a thermally conductive powder, and a phase change type thermally conductive material that softens or fluidizes at the operating temperature of a heat generating electronic component. Among these, grease is particularly easy to conduct heat.

  The grease is a base oil that is a liquid silicone such as silicone oil, or a low-viscosity silicone such as low molecular weight silicone that contains a heat conductive powder.

  Grease is highly heat conductive but has fluidity, so if it is used in locations where the thermal shock is repeated many times, it will crack and pump out (the grease will flow out of the cooling section due to the thermal expansion and contraction of the base material and the grease itself). Phenomenon) and the thermal resistance increases. In general, cracks are more likely to occur as the viscosity of grease at lower temperatures is higher, and pump-out is more likely to occur as the viscosity of grease at higher temperatures is lower. It is extremely difficult. The cracking property of the present invention means a phenomenon in which a defective portion is formed in the grease when exposed to an atmosphere of 150 ° C. or higher for a long time.

In order to solve the above problems, silicone compositions using hydrosilylation reaction by a platinum-based catalyst have been proposed (Patent Documents 1 to 4), all of which are adhesive to a substrate when used as a heat dissipation material, It pays attention to heat resistance and mechanical properties (tensile strength) as a heat-dissipating resin material, and it is judged that the effects on crack resistance and pump-out resistance in the thermal shock process are insufficient.

JP 2014-162885 A W02010 / 010841 JP 2012-102177 A JP 2014-162886 A

As a result of intensive studies, the inventors have confirmed that the grease cracking phenomenon during the thermal shock process is a phenomenon caused by re-aggregation of the filler. In order to reduce reaggregation of the filler, it has been found that it is effective to introduce a silane coupling agent that interacts with the filler surface into the silicone molecular chain. Furthermore, regarding the grease pump-out phenomenon, it was confirmed that the structure control of the crosslinked silicone was indispensable. It has been found that a silicone having a specific molecular weight, the number of vinyl groups, and a certain number of average hydrosilyl groups in the molecule is indispensable for controlling the structure of the crosslinked silicone.
The present invention has been made in view of the above problems and circumstances, and an object of the present invention is to provide a composition for thermally conductive grease that is excellent in crack resistance and pump-out resistance in the process of thermal shock. Furthermore, it aims at providing the heat conductive grease and heat radiating member which are manufactured using this composition for heat conductive grease.

The present invention employs the following means in order to solve the above problems.
(1) A composition for thermally conductive grease containing (A) component, (B) component, (C) component, (D) component and (E) component. (A) Silicone having a weight average molecular weight of 10,000 to 800,000 containing vinyl groups at both ends, (B) A weight average of containing no vinyl groups in the molecule and containing 5 to 10 hydrosilyl groups in the molecule Silicone having a molecular weight of 2000 to 10000, (C) a silicone having a weight average molecular weight of 10,000 to 40,000 containing vinyl groups at both ends and an average of 1 to 4 hydrosilyl groups in the molecule, (D) reactive double Silane coupling agent containing a bond, (E) Thermally conductive filler (2) The total of (A) component, (B) component, (C) component and (D) component in the thermally conductive grease composition is The composition for thermally conductive grease according to (1), which is 6 to 20% by mass.
(3) In the composition for thermally conductive grease, the component (A) is 2.5 to 15% by mass, the component (B) is 0.005 to 0.1% by mass, and the component (C) is 1 to 10% by mass. %, (D) component is 0.01-0.6 mass%, The composition for heat conductive grease as described in (1) or (2).
(4) The thermally conductive grease according to any one of (1) to (3), wherein the component (E) is at least one selected from silica, alumina, boron nitride, aluminum nitride, and zinc oxide. Composition.
(5) The component (E) consists of coarse powder having an average particle diameter of 15 to 100 μm, medium powder having an average particle diameter of 2 to 11 μm, and fine powder having an average particle diameter of 0.5 to 1 μm. The composition for heat conductive grease as described in any one of 1)-(4).
(6) A thermal conductive grease obtained by curing any one of the thermal conductive grease compositions according to (1) to (5).
(7) A heat radiating member in which an electronic component and a heat sink are joined via the heat conductive grease according to (6).

  In the present invention, a thermally conductive grease composition containing a specific silicone, a silane coupling agent, and a thermally conductive filler maintains the properties as a grease even after a thermal shock process, and is resistant to cracking and pump-out. I found out that it is compatible.

2 is a test piece after a pump-out resistance evaluation test of Example 2. FIG. It is a test piece after the pump-out resistance evaluation test of Comparative Example 3. It is a test piece after the crack resistance evaluation test of Example 2. It is a test piece after the crack resistance evaluation test of Comparative Example 2. It is the image which binarized the test piece after the crack resistance evaluation test of the comparative example 2.

  The composition for thermally conductive grease of the present invention comprises (A) a silicone having a vinyl group at both ends and a weight average molecular weight of 10,000 to 800,000, (B) no vinyl group in the molecule, and an average in the molecule. Silicone having a mass average molecular weight of 2000 to 10000 containing 5 to 10 hydrosilyl groups, (C) A mass average molecular weight of 10,000 containing vinyl groups at both ends and an average of 1 to 4 hydrosilyl groups in the molecule ~ 40000 silicone, (D) a silane coupling agent containing a vinyl group, and (E) a thermally conductive filler.

  The thermally conductive grease composition allows the crosslinking reaction to proceed by the addition reaction of silicone, and a flowable thermally conductive grease can be obtained by optimizing the degree of crosslinking. Examples of the curing method include a method in which a platinum-based catalyst is added to the thermally conductive grease composition and heated. Moreover, the composition for thermal conductive grease can be divided into two parts, a platinum catalyst is added to one of them, and the composition can be cured at room temperature.

  (A) The silicone containing vinyl groups at both ends has a mass average molecular weight of 10,000 to 800,000, and more preferably 10,000 to 40,000. By setting the mass average molecular weight to 10,000 or more, the pump-out resistance is improved. Moreover, crack resistance becomes favorable because a mass mean molecular weight shall be 800,000 or less. As these commercially available products, for example, SE1885 / A agent manufactured by Toray Dow Corning Co., Ltd. can be used.

  The addition amount of the component (A) in the thermally conductive grease composition is preferably 2.5 to 15% by mass, and more preferably 3 to 5% by mass. By setting it to 2.5% by mass or more, the crack resistance is improved. Moreover, pumping out resistance becomes favorable by setting it as 15 mass% or less.

  (B) Silicone having a weight average molecular weight of 2000 to 10000 containing no vinyl group in the molecule and containing an average of 5 to 10 hydrosilyl groups in the molecule is a crosslink of the cured product of the composition for heat conductive grease. It is for adjusting the degree. The number of hydrosilyl groups in the molecule is 5 to 10 on average and more preferably 5 to 7 on average. By setting the number of hydrosilyl groups to 5 or more on average, the pump-out resistance is improved. Moreover, crack resistance becomes favorable by setting it as 10 or less on average. As a commercial item, the Toray Dow Corning Silicone make, brand name "RD-1" etc. are mentioned, for example.

  The addition amount of the component (B) in the heat conductive grease composition is preferably 0.005 to 0.1% by mass, and more preferably 0.005 to 0.04% by mass. By setting it to 0.005 mass% or more, the pump-out resistance is improved. Moreover, crack resistance becomes favorable by setting it as 0.1 mass% or less.

  (C) Silicone having a weight average molecular weight of 10,000 to 40,000 containing vinyl groups at both ends and containing an average of 1 to 4 hydrosilyl groups in the molecule is the degree of crosslinking of the cured product of the composition for thermally conductive grease. It is for adjusting. The number of hydrosilyl groups in the molecule is 1 to 4 on average and more preferably 1 to 2 on average. By setting the number of hydrosilyl groups to 1 or more on average, crack resistance is improved. Moreover, pump-out resistance becomes favorable by setting it as 4 or less on average.

  (C) The mass mean molecular weight of a component is 10,000-40000, and 10000-25000 is more preferable. By setting the mass average molecular weight to 10,000 or more, the pump-out resistance is improved. Moreover, crack resistance becomes favorable by setting it as 40000 or less.

  The addition amount of the component (C) in the heat conductive grease composition is preferably 1 to 10% by mass, and more preferably 2.5 to 5% by mass. By setting the content to 1% by mass or more, the pump-out resistance is improved. Moreover, crack resistance becomes favorable by setting it as 10 mass% or less.

  (D) The silane coupling agent having a reactive double bond is used to introduce a silane coupling agent that interacts with the filler surface into the silicone molecular chain in order to reduce reaggregation of the filler. In order to introduce a silane coupling agent into the silicone molecular chain, the silane coupling agent has a reactive double bond. A reactive double bond means a vinyl group or an allyl group. (D) As a silane coupling agent containing a reactive double bond, allyltriethoxysilane, allylchlorodimethylsilane, allyltrimethoxysilane, allyltrichlorosilane, chlorodimethylvinylsilane, diethoxymethylvinylsilane, dimethoxymethylvinylsilane, Examples include trichlorovinylsilane, vinyltrimethoxysilane, dimethylethoxyvinylsilane, and vinyltris (2-methoxyethoxy) silane. Examples of commercially available products include “Z6300”, “Z6519”, and “Z6075” manufactured by Toray Dow Corning Silicone. Among these, Z6519 (allyltriethoxysilane) is preferable in terms of reactivity with the filler and generation of less harmful ethanol as a by-product after the dehydration condensation reaction with the filler.

  The amount of component (D) added to the thermally conductive grease composition is preferably 0.01 to 0.6 mass%, more preferably 0.02 to 0.3 mass%. By setting the content to 0.01% by mass or more, the crack resistance is improved. Moreover, pumping-out resistance becomes favorable by setting it as 0.60 mass% or less.

  The total of the components (A), (B), (C) and (D) in the heat conductive grease composition is preferably 6 to 20% by mass, more preferably 6 to 10% by mass. Thermal conductivity becomes favorable by setting it as 6 mass% or more. Moreover, the viscosity at the time of application | coating becomes favorable by setting it as 20 mass% or less.

  When the composition for thermally conductive grease of the present invention is divided into two parts and used, (A) silicone having a weight average molecular weight of 10,000 to 800,000 containing vinyl groups at both ends, (D) reactivity A silane coupling agent containing a double bond, and a platinum-based catalyst, (B) a mass that contains no vinyl group in the molecule and contains an average of 5 to 10 hydrosilyl groups in the molecule. It is preferable to include a silicone having an average molecular weight of 2000 to 10,000 and (C) a silicone having a weight average molecular weight of 10,000 to 40,000 containing vinyl groups at both ends and containing an average of 1 to 4 hydrosilyl groups in the molecule. . Thereby, even if a platinum-type catalyst exists, the storage stability of two agents can be improved.

  (E) The thermally conductive filler is preferably at least one selected from silica, alumina, boron nitride, aluminum nitride, and zinc oxide. Among these, alumina is preferable in terms of filling, and alumina and Aluminum nitride is preferred from the viewpoint of thermal conductivity.

(E) The thermally conductive filler may be composed of coarse powder having an average particle diameter of 15 to 100 μm, medium powder having an average particle diameter of 2 to 11 μm, and fine powder having an average particle diameter of 0.5 to 1 μm. preferable.
By setting the average particle diameter of the coarse powder to 15 μm or more, the thermal conductivity and the pump-out resistance are improved. Moreover, insulating property and crack resistance become favorable because the average particle diameter of coarse powder shall be 100 micrometers or less. Moreover, the filling amount of a heat conductive filler improves by setting the average particle diameter of medium-sized powder to 2-11 micrometers. Furthermore, heat conductivity and pump-out resistance become favorable by making the average particle diameter of a fine powder into 0.5 micrometer or more. Moreover, insulating property and crack resistance become favorable because the average particle diameter of fine powder shall be 1 micrometer or less. Thus, by using three types of thermally conductive fillers having different average particle diameters, it is possible to achieve both insulation, crack resistance, thermal conductivity and pump-out resistance while maintaining a viscosity suitable for coating. .

  The amount of (E) the heat conductive filler in the heat conductive grease composition is preferably more than 80% by mass to less than 94% by mass, and more preferably 90 to 94% by mass. Heat conductivity becomes favorable by setting it as the quantity exceeding 80 mass%. Moreover, the viscosity at the time of application | coating becomes favorable by setting it as less than 94 mass%.

  In the present invention, for example, a colorant such as “Resino Black” manufactured by Resino Color Industry Co., Ltd. is used in an amount of 0.05 to 0.2 parts by weight with respect to 100 parts by weight of the thermally conductive grease composition. You may add to the extent which does not have a bad influence on the physical property as. Moreover, you may mix | blend antioxidant, a metal corrosion inhibitor, etc. as needed.

  The composition for thermally conductive grease of the present invention can be produced by kneading with a planetary stirrer, universal mixing stirrer, kneader, hybrid mixer or the like.

  The composition for thermally conductive grease of the present invention can be used as a heat dissipating grease in a state where the crosslinking reaction is advanced by heating at 25 ° C. to 200 ° C. for 0.5 hours to 24 hours in advance. Moreover, after joining an electronic component and a heat sink, you may heat and use on the same conditions.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely, this invention is not limited to this.

<Manufacture of thermal conductive grease composition>
The following raw materials were used for the production of the composition for thermally conductive grease.
(A) Silicone having a weight average molecular weight of 10,000 to 800,000 containing vinyl groups at both ends, manufactured by Wacker, “Silgel 613 A agent”, a weight average molecular weight of 10,000,
Manufactured by Momentive, "XE14-B8530 A agent", mass average molecular weight 25000,
“SE1885 A agent” manufactured by Dow Corning, weight average molecular weight 40000,
Manufactured by Momentive, "TSE201", mass average molecular weight 800000,
(B) Silicone having a weight average molecular weight of 2000 to 10,000 containing no vinyl group in the molecule and containing 5 to 10 hydrosilyl groups in the molecule, “RD-1”, mass average molecular weight, manufactured by Dow Corning 2000, average number of hydrosilyl groups of 5,
“BLUESIL FLD 628 V12 H3.5” manufactured by Brewster Silicone, mass average molecular weight 3000, average number of hydrosilyl groups 7,
“BLUESIL FLD 626 V30 H2.5” manufactured by Brewster Silicone, mass average molecular weight 5000, average number of hydrosilyl groups 9,
Bluestar Silicone, “BLUESIL FLD 626 V70 H0.7”, mass average molecular weight 10,000, average hydrosilyl group number 10 Bluestar Silicone, “BLUESIL FLD 620 V3”, mass average molecular weight 2000, average hydrosilyl group number 2,
Further, as a comparative example, “BLUESIL FLD 626 V25 H7” manufactured by Brewster Silicone Co., Ltd., a mass average molecular weight of 3000 and an average number of hydrosilyl groups of 20 were used.
(C) Silicone having a mass average molecular weight of 10,000 to 40,000 containing vinyl groups at both ends and containing an average of 1 to 4 hydrosilyl groups in the molecule, “Silgel 613 B agent”, mass average molecular weight 10,000 1 average hydrosilyl group,
Manufactured by Momentive, "XE14-B8530 B agent", mass average molecular weight 25000, average number of hydrosilyl groups 2,
“SE1885 B agent” manufactured by Dow Corning Co., Ltd. “Si6585 B agent”, mass average molecular weight 40000, average hydrosilyl group number 4 (D) silane coupling agent containing vinyl group vinyltriethoxysilane, manufactured by Dow Corning Co., “Z6519”
(E) Thermally conductive filler coarse powder: Alumina, manufactured by Denki Kagaku Kogyo Co., Ltd., “DAW90”, average particle size 90 μm,
Alumina, manufactured by Denki Kagaku Kogyo Co., Ltd., “DAW70”, average particle size 70 μm,
Alumina, manufactured by Denki Kagaku Kogyo Co., Ltd., “DAW45”, average particle size 45 μm,
Alumina, manufactured by Sumitomo Chemical Co., Ltd., “AA-18”, average particle size 18 μm,
Aluminum nitride, manufactured by Denki Kagaku Kogyo Co., Ltd., “SAN”, average particle size 20 μm,
Medium grain powder: alumina, manufactured by Denki Kagaku Kogyo Co., Ltd., “DAS10”, average particle diameter 10 μm,
Alumina, manufactured by Denki Kagaku Kogyo Co., Ltd., “DAW05”, average particle size 5 μm,
Alumina, manufactured by Sumitomo Chemical Co., Ltd., “AA-2”, average particle size 2 μm,
Zinc oxide, manufactured by Sakai Chemical Industry Co., Ltd., “ZIMC-11”, average particle diameter 11 μm,
Fine powder: Alumina, manufactured by Sumitomo Chemical Co., Ltd., “AA-05”, average particle size 0.5 μm,
Zinc oxide, manufactured by Honjo Chemical Co., Ltd., “Type”, average particle size 0.5 μm,
Aluminum nitride, manufactured by Tokuyama, “H”, average particle size 1 μm
Platinum-based catalyst: “SFG-32” manufactured by Momentive was added to the thermally conductive resin composition in an amount of 20 ppm in terms of platinum amount.

  Various raw materials were vacuum-heated and kneaded at 150 ° C. for 3 hours and at an absolute pressure of 100 Pa or less to produce several types of thermally conductive grease. In addition, the mass average molecular weight of each compounding raw material, the average number of hydrosilyl groups, and the average particle diameter were measured with the following method.

[Mass average molecular weight]
The weight average molecular weight in terms of standard polystyrene was determined using GPC (gel permeation chromatography). The solvent was measured using “HLC-8020” manufactured by Tosoh Corporation using THF. RI (differential refractometer) was used as a detector.

[Average number of hydrosilyl groups]
1H-NMR measurement was performed using “JOEL ECP-300” manufactured by JOEL, and the number ratio of the number of vinyl groups, the number of methyl groups, and the number of hydrosilyl groups was quantified. In the case of hydrosilyl group-containing silicones containing vinyl groups at both ends, the average number of hydrosilyl groups was calculated from the number ratio of vinyl groups and hydrosilyl groups. For hydrosilyl group-containing silicones that do not have a vinyl group, the mass average molecular weight is measured using “HLC-8020” manufactured by Tosoh Corporation, and then the number ratio of the number of methyl groups to the number of hydrosilyl groups and the measured value of the mass average molecular weight. From this, the average number of hydrosilyl groups was calculated.

[Average particle size]
Measurement was performed using a “laser diffraction particle size distribution analyzer SALD-200” manufactured by Shimadzu Corporation. As an evaluation sample, 5 g of 50 cc of pure water and a heat conductive filler to be measured were added to a glass beaker, stirred using a spatula, and then subjected to dispersion treatment for 10 minutes with an ultrasonic cleaner. The dispersion liquid of the thermally conductive filler that had been subjected to the dispersion treatment was added drop by drop to the sampler portion of the apparatus using a dropper, and waited until the absorbance became measurable. Measurement was performed when the absorbance was stabilized in this manner. In the laser diffraction particle size distribution analyzer, the particle size distribution is calculated from the data of the light intensity distribution of the diffracted / scattered light by the particles detected by the sensor. The average particle size was obtained by multiplying the value of the measured particle size by the relative particle amount (difference%) and dividing by the total relative particle amount (100%).

  The physical properties of the thermally conductive grease described in Tables 1 to 4 were measured by the following methods.

[viscosity]
Using Thermo Scientific rotary rheometer MARSIII, a parallel plate of 35mmΦ is used as the upper jig, and heat conductive grease is placed on the lower plate of 35mmΦ that can be controlled by Peltier element. The sample was compressed to 1 mm, the protruding part was scraped off, and measurement was started. The viscosity at a shear rate of 0.0001 to 100 s ⁻¹ was measured, and the viscosity at a shear rate of 10 s ⁻¹ was used for evaluation. When the viscosity is lower than 400 Pas, metal mask / screen printing and application by squeegee are possible, and workability is good. When the viscosity is 400 Pas or more and less than 1200 Pas, metal mask screen printing and application by squeegee are impossible, but discharge and application from a syringe by an automatic application machine are possible. When the pressure is 1200 Pas or more and less than 1500 Pas, it is difficult to discharge and apply by an automatic application machine because it takes time. When 1500 Pas is exceeded, neither discharge nor application by an automatic coating machine is possible.
As described above, the following indices were used for the evaluation.
Excellent: Viscosity less than 400 Pas Good: Viscosity 400 Pas or more and less than 1200 Pas Possible: Viscosity 1200 Pas or more and less than 1500 Pas Impossible: Viscosity 1500 Pas or more

[Thermal conductivity]
Thermal conductivity between a rectangular copper jig with a heater embedded at 100 mm ² (10 mm × 10 mm) and a rectangular copper jig with a cooling fin attached at a tip of 100 mm ² (10 mm × 10 mm) The thermal resistance was measured in the range of 0.05 mm to 0.30 mm with the grease interposed therebetween, and the thermal conductivity was calculated from the gradient of the thermal resistance and thickness and evaluated. The thermal resistance is applied to the heater with electric power of 10 W and held for 30 minutes, and the temperature difference (° C.) between the copper jigs is measured.
Thermal resistance (° C./W)={temperature difference (° C.) / Power (W)}.
As the thermal conductivity, if it is 1 W / mK or more in view of the use of the thermal conductive grease, it is used without any problem.
In the evaluation, the following indicators were used.
Excellent: Thermal conductivity of 2.5 W / mK or more Good: Thermal conductivity of 1.0 W / mK or more and less than 2.5 W / mK Impossibility: Thermal conductivity of less than 1.0 W / mK

[Pump-out resistance]
The aluminum plate was coated with 0.03 cc × 4 points of heat conductive grease having a size of 60 mm square and a thickness of 100 μm, and vacuum defoaming was processed for 1 hour. Thereafter, the glass plate was sandwiched and adjusted so that the diameter of the thermally conductive grease was 20 mm.
Next, a weight of 4 kg was placed on the glass plate and allowed to stand for 1 day. Then, both ends of the glass plate were closed and fixed with clips, and the outer periphery of the thermally conductive grease deformed by the load was marked with an oily magic. A thermal shock test from −40 ° C. to 150 ° C. was performed to evaluate the pump-out resistance. The holding time of −40 ° C. and 150 ° C. was 30 minutes, the temperature increase / decrease from −40 ° C. to 150 ° C. and 150 to −40 ° C. was within 5 minutes, and 300 cycles were performed. In the evaluation of pump-out resistance, the evaluation of pump-out performance was as follows.
Pump-out rate (%)
= (Diameter after thermal shock test-Diameter before thermal shock test) / Diameter before thermal shock test x 100
Excellent: Pump-out rate 0%
Good: Pump-out rate 1% or more and less than 5% Possible: Pump-out rate 5% or more and less than 15% Impossible: Pump-out rate 15% or more

[Crack resistance]
A thermally conductive grease having a size of 60 mm square and a thickness of 100 μm was applied to the aluminum plate with a squeegee, vacuum defoaming was treated for 1 hour, and then the glass plate was sandwiched.
Next, a thermal shock test from −40 ° C. to 150 ° C. was performed. The holding time of −40 ° C. and 150 ° C. was 30 minutes, the temperature increase / decrease from −40 ° C. to 150 ° C. and 150 to −40 ° C. was within 5 minutes, and 300 cycles were performed.
As shown in FIG. 5, the crack resistance ratio is calculated using binarization using image processing software that can be binarized (here, GIMP 2.0), and the void area (black portion) and grease area. (White part) was measured.
Excellent: 0% crack rate
Good: Crack rate 1% or more and less than 5% Possible: Crack rate 5% or more but less than 15% Impossible: Crack rate 15% or more

As shown in Examples and Comparative Examples, the heat conductive grease using the composition for heat conductive grease of the present invention was excellent in pump-out resistance and crack resistance, and also had high heat conductivity.

Claims (7)

A composition for thermally conductive grease containing (A) component, (B) component, (C) component, (D) component and (E) component.
(A) A silicone having a weight average molecular weight of 10,000 to 800,000 containing vinyl groups at both ends (B) A weight average molecular weight having no vinyl group in the molecule and an average of 5 to 10 hydrosilyl groups in the molecule Silicone (C) of 2000 to 10,000 (C) contains vinyl groups at both ends, and contains silicone (D) reactive double bonds having a weight average molecular weight of 10,000 to 40,000 containing 1 to 4 hydrosilyl groups in the molecule. Silane coupling agent (E) Thermally conductive filler 2. The composition for heat conductive grease according to claim 1, wherein the sum of components (A), (B), (C) and (D) in the composition for heat conductive grease is 6 to 20% by mass. Composition. In the composition for thermally conductive grease,
(A) A component is 2.5-15 mass%
(B) component is 0.005-0.1 mass%
(C) 1-10 mass% of component
(D) The composition for heat conductive grease of Claim 1 or 2 which is 0.01-0.6 mass%. The composition for thermally conductive grease according to any one of claims 1 to 3, wherein the component (E) is at least one selected from silica, alumina, boron nitride, aluminum nitride, and zinc oxide. The component (E) comprises coarse powder having an average particle diameter of 15 to 100 μm, medium powder having an average particle diameter of 2 to 11 μm, and fine powder having an average particle diameter of 0.5 to 1 μm. 5. The composition for thermally conductive grease according to any one of 4 above. The heat conductive grease formed by hardening | curing the composition for heat conductive grease as described in any one of Claims 1-5. A heat dissipating member obtained by joining an electronic component and a heat sink via the thermally conductive grease according to claim 6.