JP5155033B2 - Thermally conductive silicone composition - Google Patents

Description

  The present invention relates to a thermally conductive silicone composition, and more particularly, to a thermally conductive silicone composition capable of obtaining a cured product having excellent adhesiveness and excellent thermal conductivity.

  Conventionally, in many electronic components, a heat radiating member such as a heat sink or a heat spreader has been used in order to prevent damage or performance degradation due to temperature rise during use. In order to efficiently conduct heat generated from the electronic component to the heat radiating member, generally, a heat conductive material is interposed between the electronic component and the heat radiating member.

  As the heat conductive material, a heat radiating sheet and a heat radiating grease are known (see, for example, Patent Document 1). In general, the heat dissipation sheet has the merit that it can be mounted easily, but the surface of the heat-generating electronic parts such as CPU and heat dissipation fins has many microscopic irregularities, so that it adheres securely to the adherend. Is difficult. For this reason, there is an inconvenience that an air layer is interposed between the heat radiating member and the heat radiating sheet, and as a result, the heat radiating effect cannot be sufficiently exhibited.

  On the other hand, heat radiation grease is close to liquid and is less affected by unevenness on the surface of heat-generating electronic components and heat-dissipating members compared to heat-dissipating sheets, and can reduce the interfacial thermal resistance. Although there is an advantage that it can be used, there is a problem that oil bleeding is likely to occur when used for a long time.

  For such a reason, a heat-curable heat conductive silicone composition in which a liquid silicone rubber composition is used as a base component and an adhesiveness imparting agent is blended has been proposed.

However, in the conventional heat conductive silicone composition, since there are few compounding quantities of the filler which provides heat conductivity, heat conductivity was not enough. And if the blending amount of the filler is increased in order to improve the thermal conductivity, the viscosity of the composition before curing increases, so not only the workability (coating workability) is deteriorated but also used for electronic parts. There is a problem that the wettability with respect to the metal base material (aluminum or nickel) is also deteriorated. Moreover, since the adhesiveness with respect to the said metal base material is inadequate, the adhesion defect was easy to generate | occur | produce. Furthermore, due to the further increase in the amount of heat generated in recent years due to higher integration and higher speed of electronic components, there is a need for silicone compositions with better thermal conductivity, but conventional compositions are sufficient for such demands. I couldn't respond.
JP 2004-161797 A

  The present invention was made to solve such problems, and has a low viscosity, good workability (coating workability), a silicone composition that forms a cured product having excellent adhesiveness and high thermal conductivity. The purpose is to provide.

  As a result of intensive studies to achieve the above object, the present inventors have found that (A) a low-viscosity siloxane oligomer having a trimethoxysilyl group and an alkenyl group, and (B) a filler having a different average particle diameter. (B) Thermal conductivity by blending a heat conductive filler that uses seeds in combination with each blending ratio, and (E) an adhesion-imparting agent, and (D) a specific amount of a crosslinking agent. The present inventors have found that a cured product having a low viscosity, excellent workability, and excellent adhesiveness can be obtained even when the filler is highly charged, and the present invention has been completed.

（式中、Ｚはアルケニル基、ｍは０〜２０の整数、ｎは１０〜４０の整数であり、ｍ＋ｎは１０〜４０である。）

（Ｂ）（Ｂ1）最大粒径が６０μｍ以下であって、粒径１０〜３０μｍの粒子を全体の９０重量％以上含み、平均粒径が１０μｍ以上、５０μｍ未満のアルミニウム粉末または酸化アルミニウム、（Ｂ2）最大粒径が１０μｍ以下であって、粒径２〜７μｍの粒子を全体の９０重量％以上含み、平均粒径が１μｍ以上、１０μｍ未満のアルミニウム粉末または酸化アルミニウムおよび（Ｂ3）最大粒径が３μｍ以下であって、粒径０．２〜０．８μｍの粒子を全体の６０重量％以上含み、平均粒径が０．１μｍ以上、１μｍ未満の酸化アルミニウムをそれぞれ含む熱伝導性充填剤１０００〜３０００重量部（但し、（Ｂ1）は（Ｂ）成分全体の５０〜７０vol％となる量、（Ｂ2）は（Ｂ）成分全体の１０〜３０vol％となる量、（Ｂ3）は（Ｂ）成分全体の１０〜３０vol％となる量である。）と、（Ｃ）白金系触媒の触媒量と、（Ｄ）１分子中にケイ素原子に結合した水素原子を３個以上有するポリオルガノハイドロジェンシロキサンを、（Ａ）成分のアルケニル基１個に対してケイ素原子に結合した水素原子が０．５〜２．０個となる量、および（Ｅ）接着性付与剤１．０〜１０重量部を含有することを特徴としている。 That is, the thermally conductive silicone composition of the present invention has (A) a viscosity of 10 to 100 mPa · s at 23 ° C., and 100 parts by weight of an alkenyl group-containing siloxane oligomer represented by the following general formula:

(In the formula, Z is an alkenyl group, m is an integer of 0 to 20, n is an integer of 10 to 40, and m + n is 10 to 40.)

(B) (B1) An aluminum powder or aluminum oxide having a maximum particle size of 60 μm or less and containing 90% by weight or more of particles having a particle size of 10 to 30 μm and an average particle size of 10 μm or more and less than 50 μm, (B2 ) a the maximum particle size of 10 [mu] m or less, contains particles having a particle diameter 2~7μm total 90 wt% or more, an average particle diameter of 1μm or more, aluminum powder or aluminum oxide and (B3 less than 10 [mu] m) is the maximum particle size Thermally conductive filler 1000 that includes 3 μm or less of particles having a particle size of 0.2 to 0.8 μm and 60% by weight or more of the whole, and an aluminum oxide having an average particle size of 0.1 μm or more and less than 1 μm. 3000 parts by weight (provided that (B1) is an amount that is 50 to 70 vol% of the entire component (B), (B2) is an amount that is 10 to 30 vol% of the entire component (B), and (B3) is the component (B) Overall 10 (C) a catalyst amount of a platinum-based catalyst, and (D) a polyorganohydrogensiloxane having three or more hydrogen atoms bonded to silicon atoms in one molecule (A ) An amount of 0.5 to 2.0 hydrogen atoms bonded to a silicon atom with respect to one alkenyl group of the component, and (E) 1.0 to 10 parts by weight of an adhesion promoter. It is a feature.

  The silicone composition of the present invention having the above structure forms a cured product having low viscosity, good workability (coating workability), excellent adhesion, and good thermal conductivity.

  Hereinafter, the thermally conductive silicone composition of the present invention will be described in detail.

[(A) component]
The alkenyl group-containing siloxane oligomer of component (A) has an alkenyl group at a part of the terminal and further has a trimethoxysilyl group. The component (A) serves as a surface treatment agent (wetter) for the thermally conductive filler that is the component (B) described later, and is good for the composition even if a large amount of the thermally conductive filler is blended. Gives fluidity and workability. Moreover, (A) component performs addition reaction with the crosslinking agent (polyorganohydrogensiloxane) which has Si-H group which is (D) component in presence of the platinum-type catalyst which is (C) component.

で表される。 The component (A) has the following general formula:

It is represented by

  In formula, Z is an alkenyl group, for example, C2-C6 alkenyl groups, such as a vinyl group, an allyl group, a butenyl group, a petenyl group, a hexenyl group, are mentioned. A vinyl group is preferred. m is an integer of 0-20, preferably an integer of 0-5. n is an integer of 10 to 40, preferably an integer of 20 to 30. m + n is 10 to 40, preferably 20 to 30. When the value of m + n is less than 10, since the molecular weight of the component (A) is low, the unreacted product after crosslinking is likely to bleed out. On the other hand, if the value of m + n exceeds 40, an increase in the viscosity of the composition cannot be suppressed, and good workability cannot be obtained.

  (A) The viscosity in 23 degreeC of a component is 10-100 mPa * s, Preferably it is 30-80 mPa * s. When the viscosity is less than 10 mPa · s, since the molecular weight is low, unreacted materials after crosslinking are likely to bleed out. On the other hand, when the viscosity exceeds 100 mPa · s, it is possible to disperse the component (B) when the thermally conductive filler of the component (B) and the component (A) are kneaded in the production process of the composition. Tends to be putty-like, making it difficult to blend other ingredients.

[Component (B)]
(B) The heat conductive filler of a component is a component which provides heat conductivity to a composition, and uses together 3 types of aluminum powder or aluminum oxide powder which has a specific average particle diameter. That is, as the component (B), (B1) an aluminum powder or aluminum oxide powder having an average particle diameter of 10 μm or more and less than 50 μm, (B2) an aluminum powder or aluminum oxide powder having an average particle diameter of 1 μm or more and less than 10 μm, ( B3) An aluminum oxide powder having an average particle size of 0.1 μm or more and less than 1 μm is used. When electrical insulation is required for the present composition, it is preferable that the components (B1), (B2) and (B3) are all aluminum oxide powder.

  (B1) The average particle diameter of a component is 10 micrometers or more and less than 50 micrometers, Preferably it is 10-30 micrometers. When the average particle size exceeds 50 μm, the stability of the composition is deteriorated and oil separation tends to occur. The maximum particle size of (B1) is 60 μm or less, and it is preferable that particles having a particle size of 10 to 30 μm are contained in 90% by weight or more of the total component (B1). As long as the average particle size is in the above range, those having different particle sizes or particle size distributions may be mixed and used. The average particle size and the maximum particle size are values measured by a laser diffraction method. The shape of (B1) is not limited, and may be, for example, either a spherical shape or an indefinite shape.

  (B2) The average particle diameter of a component is 1 micrometer or more and less than 10 micrometers, Preferably it is 2-7 micrometers. The maximum particle size of (B2) is 10 μm or less, and it is preferable that particles having a particle size of 2 to 7 μm are contained in 90% by weight or more of the total component (B2). As long as the average particle size is in the above range, those having different particle sizes or particle size distributions may be mixed and used. The shape of (B2) is not limited, and may be, for example, either a spherical shape or an indefinite shape.

  (B3) The average particle diameter of a component is 0.1 micrometer or more and less than 1 micrometer, Preferably it is 0.2-0.8 micrometer. If the average particle size is less than 0.1 μm, it is difficult to obtain a desired low-viscosity composition. The maximum particle size of (B3) is 3 μm or less, and it is preferable that particles having a particle size of 0.2 to 0.8 μm are contained in an amount of 60% by weight or more of the total component (B3). As long as the average particle size is in the above range, those having different particle sizes or particle size distributions may be mixed and used. The shape of (B3) is not limited, and may be either spherical or indefinite.

  (B) The compounding quantity of a component shall be 1000-3000 weight part with respect to 100 weight part of (A) component, Preferably it is 1500-2500 weight part. If the blending amount is less than 1000 parts by weight, the desired thermal conductivity cannot be obtained. On the other hand, when it exceeds 3000 parts by weight, the fluidity of the composition is lowered and the workability is deteriorated.

  The blending ratio of the components (B1) to (B3) constituting the component (B) is such that the component (B1) is 50 to 70 vol% (volume%) with respect to the entire component (B), preferably 55. It is the quantity which becomes -65 vol%. The specific gravity of aluminum is 2.70, and the specific gravity of aluminum oxide (alumina) is 3.97. When the blending ratio of the component (B1) is out of the above range, when the component (B) and the component (A) are kneaded, the component (B) is not easily dispersed and becomes powdery. Becomes impossible.

  Further, the blending ratio of the component (B2) is an amount that becomes 10 to 30 vol%, preferably 15 to 25 vol%, with respect to the entire component (B). When the blending ratio of the component (B2) is out of the above range, the viscosity of the composition increases and good workability cannot be obtained.

  The blending ratio of the component (B3) is an amount that becomes 10 to 30 vol%, preferably 15 to 25 vol%, with respect to the entire component (B). When the blending ratio of the component (B3) exceeds 30 vol% of the total component (B), when the component (B) and the component (A) are kneaded, the component (B) is easily dispersed without being dispersed. It becomes impossible to mix the ingredients. On the other hand, if it is less than 10 vol% of the total component (B), the viscosity of the composition increases, and good workability cannot be obtained.

[Component (C)]
As the component (C), a known platinum-based catalyst can be used as a catalyst used in the hydrosilylation reaction. Examples of the platinum-based catalyst include platinum black, platinous chloride, chloroplatinic acid, a reaction product of chloroplatinic acid and a monohydric alcohol, a complex of chloroplatinic acid with olefins and vinyl siloxane, platinum bisacetoacetate, and the like. Can be mentioned.

  The blending amount of the component (C) may be an amount necessary for curing the composition, and can be appropriately adjusted according to a desired curing rate. Usually, it is preferable to set it as 0.01-100 ppm in conversion of a platinum element with respect to the total amount of a composition. If the blending amount is less than 0.01 ppm, the composition will not be sufficiently cured, and even if an amount exceeding 100 ppm is blended, the curing rate of the composition will not be significantly improved.

[(D) component]
The polyorganohydrogensiloxane of component (D) is a crosslinking agent and has 3 or more hydrogen atoms bonded to silicon atoms in one molecule. This hydrogen atom may be bonded to the silicon atom at the end of the molecular chain, may be bonded to the silicon atom in the middle of the molecular chain, or may be bonded to both.

As the component (D), the general formula:
^{_{R 2 p H q SiO [4-}} (p + q)] / 2
What is shown by is used.

In the formula, R ² is the same or different substituted or unsubstituted monovalent hydrocarbon group excluding an aliphatic unsaturated bond. Examples of R ² include 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 hexyl group, a cyclohexyl group, and an octyl group; Aryl groups; aralkyl groups such as benzyl and phenylethyl groups; and those in which some or all of the hydrogen atoms are substituted with halogen atoms such as fluorine, chlorine, bromine or cyano groups, such as chloro A methyl group, a bromoethyl group, a trifluoropropyl group, a cyanoethyl group and the like can be mentioned. From the viewpoint of ease of synthesis and cost, an alkyl group having 1 to 4 carbon atoms such as methyl group, ethyl group, propyl group, isopropyl group, butyl group and isobutyl group is preferable, and a methyl group is more preferable.

  p and q are positive numbers satisfying 0.5 ≦ p ≦ 2, 0 <q ≦ 2, and 0.5 <p + q ≦ 3, respectively, preferably 0.6 ≦ p ≦ 1.9, 0.8. It is a positive number satisfying 01 ≦ q ≦ 1.0 and 0.6 ≦ p + q ≦ 2.8.

  The molecular structure of component (D) may be any of linear, branched, cyclic, or three-dimensional network, and can be used alone or in combination of two or more.

  (D) The viscosity in 23 degreeC of a component is 0.001-1 Pa.s, Preferably it is 0.01-0.5 Pa.s.

  Component (D) is blended in such an amount that 0.5 to 2.0 hydrogen atoms bonded to silicon atoms in component (D) are present per alkenyl group in component (A), preferably Is an amount of 0.7 to 1.5. If the number of hydrogen atoms bonded to the silicon atom is less than 0.5, sufficient crosslinking of the cured product cannot be obtained, and it is difficult to obtain a desired curability. On the other hand, even if the number exceeds 2.0, there is no significant difference in curability and hardness of the cured product, but the blending ratio of the thermally conductive filler as the component (B) is reduced, and as a result, the thermal conductivity is reduced. Will be reduced.

[(E) component]
The component (E) is an adhesiveness imparting agent, and one or more organic silicon compounds selected from the group consisting of the components (a), (b) and (c) shown below can be used.

で示され、別個のシロキサン単位に含まれる基を分子中に少なくとも１個有するポリシロキサン骨格を持つものであることが好ましい。ここで、Ｑ^１は、合成の容易さと耐加水分解性の点から、炭素原子数２個以上の直鎖状または分岐状のアルキレン基が好ましく、特にメチレン基あるいはイソプロピレン基が好ましい。またＱ^２は、耐加水分解性の点から、炭素原子数３個以上の直鎖状または分岐状のアルキレン基が好ましく、特にプロピレン基が好ましい。さらに、一般式（Ｉ）におけるＲ^１は、炭素数１〜４のアルキル基を表す。メチル基、エチル基、プロピル基、イソプロピル基およびブチル基を例示することができるが、組成物が良好な接着性を示すことから、メチル基およびエチル基が好ましい。このような側鎖を含むシロキサン単位は、分子中のＳｉ−Ｈ結合にアクリル酸またはメタクリル酸のトリアルコキシシリルプロピルエステルを付加させるなどの方法で合成することができる。このような有機ケイ素化合物のシロキサン骨格は、環状でも鎖状でもよく、またそれらの混合物でもよいが、合成の容易さから環状ポリシロキサン骨格を有するものが最も好ましい。環状の場合は、合成の容易さから、シロキサン環を形成するケイ素原子の数は３〜６個、好ましくは４個のものが用いられる。鎖状の場合は、分子量が大きいと粘度が高くなって合成や取り扱いに不便になるので、シロキサン鎖を形成するケイ素原子は、２〜２０個、好ましくは４〜１０個のものが用いられる。 The organosilicon compound as component (a) is a silane derivative or a polysiloxane derivative, and from the viewpoint of ease of synthesis, at least one hydrogen atom bonded to a silicon atom, that is, a Si—H bond, is represented by the general formula (I )

And a polysiloxane skeleton having at least one group contained in a separate siloxane unit in the molecule. Here, Q ¹ is preferably a linear or branched alkylene group having 2 or more carbon atoms, particularly a methylene group or an isopropylene group, from the viewpoint of ease of synthesis and hydrolysis resistance. Q ² is preferably a linear or branched alkylene group having 3 or more carbon atoms from the viewpoint of hydrolysis resistance, and particularly preferably a propylene group. Further, ^{R 1} in the general formula (I) represents an alkyl group having 1 to 4 carbon atoms. A methyl group, an ethyl group, a propyl group, an isopropyl group, and a butyl group can be exemplified, but a methyl group and an ethyl group are preferable because the composition exhibits good adhesiveness. Such a siloxane unit containing a side chain can be synthesized by a method such as adding a trialkoxysilylpropyl ester of acrylic acid or methacrylic acid to a Si—H bond in the molecule. Such a siloxane skeleton of the organosilicon compound may be cyclic or chain-like, or a mixture thereof, but those having a cyclic polysiloxane skeleton are most preferable from the viewpoint of ease of synthesis. In the case of a ring, the number of silicon atoms forming the siloxane ring is 3 to 6, preferably 4, for ease of synthesis. In the case of a chain, a large molecular weight increases the viscosity, which is inconvenient for synthesis and handling. Therefore, 2 to 20 silicon atoms, preferably 4 to 10 silicon atoms are used to form a siloxane chain.

で表されるシロキサンなどが例示される。 The organosilicon compound as component (b) is a silane or siloxane containing at least two alkoxy groups in the molecule and containing an epoxy group. From the viewpoint of improving the adhesion to the substrate, the number of alkoxy groups bonded to the silicon atom is more preferably 3 or more. As the organosilicon compound of component (b), γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldiethoxy Silanes such as silane, formula:

The siloxane etc. which are represented by these are illustrated.

で表されるシランおよびその加水分解縮合物が例示される。 The organosilicon compound as component (c) is an alkoxysilane or siloxane having a hydrocarbon group having an unsaturated double bond. From the viewpoint of improving the adhesion to the substrate, the number of alkoxy groups bonded to the silicon atom is more preferably 3 or more. Examples of the hydrocarbon group having an unsaturated double bond include alkenyl groups such as vinyl group and allyl group; groups such as acryloyl group, methacryloyl group, acryloxypropyl group, and methacryloxypropyl group. As the organosilicon compound of component (c), vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, and the formula:

And the hydrolysis-condensation product thereof are exemplified.

  These organosilicon compounds of components (a), (b) and (c) are all useful as an adhesion-imparting agent for addition-reaction type compositions, and can be used alone, but have an adhesive property to a substrate. Two or more kinds may be used in combination in order to further improve. The blending amount of the component (E) composed of the components (a), (b) and (c) is 1 to 10 parts by weight with respect to 100 parts by weight of the component (A). When the amount is less than 1 part by weight, sufficient adhesive strength cannot be obtained, and when it exceeds 10 parts by weight, the mechanical properties of the cured product are deteriorated, which is not preferable.

[Other optional ingredients]
The heat-conductive silicone composition of the present invention comprises the above components (A) to (E) as basic components, and in the range that does not impair the object of the present invention, if necessary, the reinforcing silica and flame retardancy An imparting agent, a heat resistance improver, a plasticizer, a colorant, and the like may be added. In addition, a reaction regulator such as triallyl isocyanurate can be added.

[Method for producing thermally conductive silicone composition]
In the production of the heat conductive silicone composition of the present invention, the order of addition of the respective components is not particularly limited. For example, the alkenyl group-containing siloxane oligomer (A) and the heat (B) are used. After kneading the conductive filler with a kneader described later, (C) a platinum-based catalyst and (D) polyorganohydrogensiloxane which is a crosslinking agent, and other optional components as necessary are kneaded. Is preferred. Examples of the kneading machine include a planetary mixer equipped with a heating means and a cooling means, a three-roller, a kneader, and a Shinagawa mixer. These can be used alone or in combination.

  The viscosity of the heat conductive silicone composition of the present invention is preferably 30 to 300 Pa · s at 23 ° C. When the viscosity exceeds 300 Pa · s, for example, when the composition is stored in a syringe or the like and injected into the gap between the heat-generating electronic component and the heat-dissipating member, it becomes difficult to discharge, and workability is likely to deteriorate. On the other hand, if it is less than 30 Pa · s, liquid dripping is likely to occur during coating.

  Examples of the method for curing the thermally conductive silicone composition of the present invention include a method of leaving the composition at room temperature and a method of heating at a temperature of 50 to 200 ° C. From the viewpoint of rapid curing, it is preferable to employ a heating method. The resulting cured product has excellent thermal conductivity and good adhesion to a metal substrate such as aluminum or nickel.

  The thermal conductivity of the cured product at 23 ° C. (measured by the hot wire method) is 3.0 W / (m · K) or more, and it is also possible to increase the thermal conductivity to 4.5 W / (m · K). is there. If the thermal conductivity is less than 3.0 W / (m · K), the thermal conductivity performance may be insufficient depending on the application, which is not preferable because the application is limited.

  As described above, the thermally conductive silicone composition of the present invention forms a cured product having a low viscosity, excellent coating workability, excellent adhesion, and good thermal conductivity. Therefore, it is suitable as a heat conductive material interposed between the heat-generating electronic component and the heat dissipation member.

  Next, a semiconductor device using the thermally conductive silicone composition of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view schematically showing a configuration of a semiconductor device.

  The semiconductor device 1 includes the above-described heat conduction between a heat-generating electronic component 3 such as a CPU mounted on a wiring board 2 and a heat spreader 4 provided in the periphery to dissipate heat generated from the electronic component. The cured product layer 5 of the conductive silicone composition has a structure. The exothermic electronic component 3 and the heat spreader 4 are bonded via the cured product layer 5, and heat dissipation from the exothermic electronic component 3 to the heat spreader 4 is aided. Further, a heat conductive layer 7 is interposed between the heat spreader 4 and a heat radiating member such as the heat sink 6. The heat conductive layer 7 is composed of a heat conductive silicone grease or a heat conductive sheet, but may be a cured layer of the above-described heat conductive silicone composition. When the heat conductive layer 7 is made of a heat conductive silicone grease or a heat conductive sheet, it is easy to remove a heat radiating member such as the heat sink 6 from the heat spreader 4 for repair or the like. In the figure, reference numeral 8 denotes a connection bump for mounting the heat-generating electronic component 3 on the wiring substrate 2, and 9 denotes a sealing layer for hermetically sealing the bump connection portion.

  The thickness of the cured product layer 5 of the heat conductive silicone composition is preferably 5 to 300 μm. If the thickness is less than 5 μm, a gap may be formed between them, and adhesion is insufficient. On the other hand, if it is thicker than 300 μm, the thermal resistance increases and the heat dissipation effect tends to deteriorate.

  In such a semiconductor device 1, a heat conductive silicone composition is applied to a heat-generating electronic component 3 mounted on a wiring board 2 with a thickness of 5 to 300 μm, for example, with a syringe, and a heat spreader 4 is placed thereon to heat. After curing, a heat conductive layer 7 such as a heat conductive silicone grease and a heat sink 6 are further disposed, and the heat sink 6 and the wiring board 2 are pressed.

  The heat conductive silicone composition of this invention is demonstrated in detail by an Example. The characteristics of the thermally conductive silicone compositions obtained in the examples and comparative examples were measured and evaluated as follows, and the results are shown in Table 1. The characteristics shown in Table 1 are values measured at 23 ° C., and the average particle diameter is a value measured by a laser diffraction method.

[viscosity]
The viscosity at 23 ° C. of the thermally conductive silicone composition was measured using a viscometer (trade name: Brookfield Engineering, HBT type).

[Thermal conductivity]
The silicone compositions obtained in Examples 1 and 2 and Comparative Example 2 were poured into a mold having a depth of 2.5 cm and cured by heating in a hot air dryer at 150 ° C. for 1 hour. After the cured product was cooled to room temperature, the thermal conductivity was measured using a thermal conductivity meter (trade name: QTM-500) manufactured by Kyoto Electronics Industry Co., Ltd.

[Adhesiveness]
Two aluminum plates of 80 mm × 25 mm × 2 mm were placed in parallel with the long sides overlapped by 10 mm, and the layers of the silicone compositions obtained in Examples 1 and 2 and Comparative Example 2 ( After forming a thickness of 1 mm, it was cured by heating at 150 ° C. for 1 hour and allowed to cool. In this way, a sample for an adhesion test for an aluminum plate was prepared. Similarly, a sample for an adhesion test with respect to a nickel-plated plate was prepared. The sample thus obtained was mounted on a tensile tester and 10 mm / min. An adhesion test was conducted at a tensile speed of 5 to examine whether there was any peeling. Those without peeling were evaluated as having good adhesion.

で表されるビニル基含有シロキサンオリゴマー（式中、Ｖｉはビニル基を意味する。ビニル基量０．６８ｍｍｏｌ／ｇ）１００重量部と、（Ｂ1-1）平均粒径１８μｍの丸み状の酸化アルミニウム１１４０重量部と、（Ｂ2）平均粒径３μｍの丸み状の酸化アルミニウム３８０重量部、および（Ｂ3）平均粒径０．４μｍの丸み状の酸化アルミニウム３８０重量部を、プラネタリーミキサーで１５０℃に加熱して１２０分間混練した後、３０℃まで冷却した。次いで、（Ｃ）塩化白金酸のビニルシロキサン錯体化合物（白金量２．０重量％）０．２重量部（白金元素量として０．５ｐｐｍ）と、（Ｄ）２３℃における粘度が０．１Ｐａ・ｓであり、
式：(ＣＨ_３)_３ＳｉＯ[ＳｉＨ(ＣＨ_３)Ｏ]_２３[Ｓｉ(ＣＨ_３)_２Ｏ]_１６Ｓｉ(ＣＨ_３)_３
で表されるポリオルガノハイドロジェンシロキサン（Ｓｉ−Ｈ基の含有量８．４ｍｍｏｌ／ｇ）８．１重量部と、（Ｅ-1）γ−グリシドキシプロピルトリメトキシシラン２重量部と、（Ｅ-2）γ−メタクリロキシプロピルトリメトキシシラン２重量部、および反応調節剤としてトリアリルイソシアヌレート０．５重量をそれぞれプラネタリーミキサーに添加し、常温（２３℃）で３０分間均一に混練して、熱伝導性シリコーン組成物を得た。この組成物の特性を測定し、結果を表１に示した。 Example 1
First, (A-1) the viscosity at 23 ° C. is 0.050 Pa · s, and the following formula:

100 parts by weight of a vinyl group-containing siloxane oligomer represented by the formula (wherein Vi represents a vinyl group, vinyl group amount 0.68 mmol / g) and (B1-1) round aluminum oxide having an average particle size of 18 μm 1140 parts by weight, (B2) 380 parts by weight of round aluminum oxide having an average particle diameter of 3 μm, and (B3) 380 parts by weight of round aluminum oxide having an average particle diameter of 0.4 μm were brought to 150 ° C. with a planetary mixer. After heating and kneading for 120 minutes, the mixture was cooled to 30 ° C. Next, (C) 0.2 parts by weight of a vinylsiloxane complex compound of chloroplatinic acid (platinum amount 2.0% by weight) (0.5 ppm as the amount of platinum element) and (D) a viscosity at 23 ° C. of 0.1 Pa · s,
Formula: (CH ₃ ) ₃ SiO [SiH (CH ₃ ) O] ₂₃ [Si (CH ₃ ) ₂ O] ₁₆ Si (CH ₃ ) ₃
8.1 parts by weight of a polyorganohydrogensiloxane represented by formula (Si-H group content 8.4 mmol / g), (E-1) 2 parts by weight of γ-glycidoxypropyltrimethoxysilane, E-2) Add 2 parts by weight of γ-methacryloxypropyltrimethoxysilane and 0.5 parts by weight of triallyl isocyanurate as a reaction regulator, respectively, and knead uniformly at room temperature (23 ° C.) for 30 minutes. Thus, a heat conductive silicone composition was obtained. The properties of this composition were measured and the results are shown in Table 1.

Example 2
In the same manner as in Example 1, except that 1140 parts by weight of aluminum oxide (B1-1) having an average particle diameter of 18 μm in Example 1 was changed to 770 parts by weight of aluminum having (B1-2) an average particle diameter of 20 μm, A conductive silicone composition was obtained. The properties of this composition were measured and the results are shown in Table 1.

で表され、２３℃における粘度が０．１８０Ｐａ・ｓであるビニル基含有シロキサンオリゴマー１００重量部に変えたところ、（Ｂ）成分が（Ａ）成分に分散したがパテ状となったため、組成物の調製を中止した。 Comparative Example 1
In Example 1, (A-1) 100 parts by weight of a vinyl group-containing siloxane oligomer having a viscosity at 23 ° C. of 0.050 Pa · s is represented by the formula (A-2):

When the viscosity was changed to 100 parts by weight of a vinyl group-containing siloxane oligomer having a viscosity at 23 ° C. of 0.180 Pa · s, the component (B) was dispersed in the component (A) but became putty. The preparation of was stopped.

で表されるビニル基をもたないシロキサンオリゴマー２０重量部と、（Ａ-4）２３℃における粘度が０．１０Ｐａ・ｓの両末端ビニル基含有シロキサン（ビニル基量０．３３ｍｍｏｌ／ｇ）８０重量部との混合物を用いた。また、（Ｄ）成分であるポリオルガノハイドロジェンシロキサンの配合量を３．１４重量部とした。それ以外は実施例１と同様にして、熱伝導性シリコーン組成物を得た。この組成物の特性を測定し、結果を表１に示した。 Comparative Example 2
Instead of 100 parts by weight of the vinyl group-containing siloxane oligomer having a viscosity at 23 ° C. of (A-1) of Example 1 of (A-3), the viscosity at 23 ° C. of (A-3) is 0.050 Pa · s. The following formula:

20 parts by weight of a siloxane oligomer having no vinyl group and (A-4) a siloxane containing both terminal vinyl groups having a viscosity of 0.10 Pa · s at 23 ° C. (vinyl group amount 0.33 mmol / g) 80 A mixture with parts by weight was used. Moreover, the compounding quantity of polyorganohydrogensiloxane which is (D) component was 3.14 weight part. Other than that was carried out similarly to Example 1, and obtained the heat conductive silicone composition. The properties of this composition were measured and the results are shown in Table 1.

Comparative Example 3
In Example 1, (B1-1) the amount of aluminum oxide having an average particle size of 18 μm was 1520 parts by weight, and (B2) the amount of aluminum oxide having an average particle size of 3 μm was 190 parts by weight. Further, the blending amount of (B3) aluminum oxide having an average particle diameter of 0.4 μm was 190 parts by weight. Otherwise, preparation was performed in the same manner as in Example 1. However, since the component (B) was not dispersed in the component (A) and remained in powder form, the preparation of the composition was stopped.

Comparative Example 4
In Example 1, (B1-1) the amount of aluminum oxide having an average particle size of 18 μm was 760 parts by weight, and (B2) the amount of aluminum oxide having an average particle size of 3 μm was 570 parts by weight. The blending amount of (B3) aluminum oxide having an average particle size of 0.4 μm was 570 parts by weight. Otherwise, preparation was performed in the same manner as in Example 1. However, since the component (B) was not dispersed in the component (A) and remained in powder form, the preparation of the composition was stopped.

Comparative Example 5
In Example 1, (B1-1) the amount of aluminum oxide having an average particle size of 18 μm was 950 parts by weight, and (B2) the amount of aluminum oxide having an average particle size of 3 μm was 760 parts by weight. Further, the blending amount of (B3) aluminum oxide having an average particle diameter of 0.4 μm was 190 parts by weight. Otherwise, preparation was performed in the same manner as in Example 1. However, since the component (B) was not dispersed in the component (A) and remained in powder form, the preparation of the composition was stopped.

Comparative Example 6
The amount of (B1-1) aluminum oxide having an average particle size of 18 μm in Example 1 was 1330 parts by weight, and the amount of (B2) 380 parts by weight of aluminum oxide having an average particle size of 3 μm was 95 parts by weight. The blending amount of (B3) aluminum oxide having an average particle size of 0.4 μm was 475 parts by weight. Otherwise in the same manner as in Example 1, the component (B) was dispersed in the component (A) but became putty, so the preparation of the composition was stopped.

Comparative Example 7
In Example 1, (B1-1) the amount of aluminum oxide having an average particle size of 18 μm was 950 parts by weight, and (B2) the amount of aluminum oxide having an average particle size of 3 μm was 190 parts by weight. The blending amount of (B3) aluminum oxide having an average particle size of 0.4 μm was 760 parts by weight. Otherwise, preparation was performed in the same manner as in Example 1. However, since the component (B) was not dispersed in the component (A) and remained in powder form, preparation of the composition was stopped.

Comparative Example 8
In Example 1, (B1-1) the amount of aluminum oxide having an average particle size of 18 μm was 1330 parts by weight, and (B2) the amount of aluminum oxide having an average particle size of 3 μm was 475 parts by weight. The blending amount of (B3) aluminum oxide having an average particle size of 0.4 μm was 95 parts by weight. Otherwise, preparation was performed in the same manner as in Example 1. However, since the component (B) was dispersed in the component (A) but became putty, the preparation of the composition was stopped.

  As is clear from Table 1, the silicone compositions of Examples 1 and 2 are highly filled with the thermally conductive filler as the component (B) but have a low viscosity, so that good coating performance and coating work are achieved. Have sex. Moreover, the cured product exhibits extremely high thermal conductivity of 4.5 W / (m · K) or more, and is excellent in adhesion to metal substrates (aluminum plates and nickel plated plates).

It is sectional drawing which shows an example of the semiconductor device to which the heat conductive silicone composition of this invention is applied.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Semiconductor device, 2 ... Wiring board, 3 ... Exothermic electronic component, 4 ... Heat spreader, 5 ... Hardened | cured material layer of a heat conductive silicone composition, 6 ... Heat sink.

Claims (4)

(A) The viscosity at 23 ° C. is 10 to 100 mPa · s, and 100 parts by weight of an alkenyl group-containing siloxane oligomer represented by the following general formula:

(In the formula, Z is an alkenyl group, m is an integer of 0 to 20, n is an integer of 10 to 40, and m + n is 10 to 40.)
(B) (B1) An aluminum powder or aluminum oxide having a maximum particle size of 60 μm or less and containing 90% by weight or more of particles having a particle size of 10 to 30 μm and an average particle size of 10 μm or more and less than 50 μm, (B2 ) Aluminum powder or aluminum oxide having a maximum particle size of 10 μm or less, containing 90% by weight or more of particles having a particle size of 2 to 7 μm , an average particle size of 1 μm or more and less than 10 μm, and (B3) the maximum particle size Thermally conductive filler 1000 that includes 3 μm or less of particles having a particle size of 0.2 to 0.8 μm and 60% by weight or more of the whole, and an aluminum oxide having an average particle size of 0.1 μm or more and less than 1 μm. 3000 parts by weight (provided that (B1) is 50 to 70% by volume (vol%) of the total component (B), (B2) is 10 to 30 vol% of the total (B) component, (B3) (B) component As the amount to be 10 to 30 vol% of the body.)
(C) the amount of platinum-based catalyst;
(D) A polyorganohydrogensiloxane having three or more hydrogen atoms bonded to silicon atoms in one molecule, wherein 0.5 to 0.5 hydrogen atoms bonded to silicon atoms per one alkenyl group of component (A) A thermally conductive silicone composition comprising an amount of 2.0, and (E) 1.0 to 10 parts by weight of an adhesion-imparting agent. The adhesiveness imparting agent as the component (E) is
The thermally conductive silicone composition according to claim 1, wherein the composition is one or more organic silicon compounds selected from the group consisting of the following (a) to (c).
(A) at least one hydrogen atom bonded to a silicon atom in the molecule;

(In the formula, Q ¹ and Q ² represent a linear or branched alkylene group, and R ¹ represents an alkyl group having 1 to 4 carbon atoms.) Organic having at least one group represented in the molecule Silicon compound (b) Organosilicon compound having at least two alkoxy groups bonded to a silicon atom and at least one epoxy group in the molecule (c) At least one alkoxy group bonded to a silicon atom in the molecule And an organosilicon compound having at least one hydrocarbon group having an unsaturated double bond in the molecule The thermally conductive silicone composition according to claim 1 or 2, wherein the viscosity at 23 ° C before curing is 30 to 300 Pa · s. The thermally conductive silicone composition according to any one of claims 1 to 3, wherein the cured product has a thermal conductivity of 3.0 W / (m · K) or more.

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