JP6087499B2 - Thermally conductive silicone composition - Google Patents

Description

  The present invention relates to a novel organosilicon compound, and more particularly to an organosilicon compound that can be suitably used as a wetter (dispersant) for a silicone composition highly filled with a filler such as a heat conductive filler.

  Since many electronic components generate heat during use, it is necessary to remove the heat from the electronic component in order for the electronic component to function properly. In particular, an integrated circuit element such as a CPU used in a personal computer has an increased amount of heat generated due to an increase in operating frequency, and countermeasures against heat are an important issue.

  Many methods have been proposed as means for removing this heat. In particular, for electronic components that generate a large amount of heat, a method has been proposed in which a heat conductive material such as a heat conductive grease or a heat conductive sheet is interposed between the electronic component and a member such as a heat sink (patented). Reference 1 and Patent Reference 2).

  Moreover, as such a heat conductive material, a heat radiation grease or a heat radiation adhesive based on silicone and containing zinc oxide or alumina powder is known (see Patent Document 3 and Patent Document 4).

  In order to obtain a thermally conductive material based on silicone and having high thermal conductivity, it is necessary to highly fill the thermally conductive filler. However, if just high filling is attempted, the fluidity of the heat conductive material is significantly reduced, workability such as coating properties (dispensing properties, screen printing properties) is deteriorated, and the fineness of the surface of electronic components and heat sinks is further reduced. The problem that it becomes impossible to follow unevenness arises. In order to solve this problem, a method is proposed in which the thermal conductive filler is surface-treated with a silane coupling agent (wetter) and dispersed in the base polymer silicone to maintain the fluidity of the thermal conductive material. Has been.

  Currently, there are alkoxysilanes having an alkyl group (Patent Documents 5 and 6) as frequently used wetters. When these wetters use methyl silicone as a base polymer, the viscosity can be lowered, but when a substituent other than a methyl group is introduced into the base silicone, the effect is not necessarily sufficient.

JP-A-56-28264 JP-A 61-157487 Japanese Patent Publication No.52-33272 Japanese Patent Publication No.59-52195 Japanese Patent No. 3290127 Japanese Patent No. 3372487

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an organosilicon compound suitable as a wetter capable of highly filling a silicone with a filler and imparting good workability. To do.

（式中Ｒ^１は同一または異種の１価有機基であり、ｊおよびｋは０または１であり、ｍは１〜５の整数であり、ｎは６〜２０の整数である。） In order to solve the above problems, the present invention provides an organosilicon compound represented by the following general formula (1).

(In the formula, R ¹ is the same or different monovalent organic group, j and k are 0 or 1, m is an integer of 1 to 5, and n is an integer of 6 to 20.)

  Such an organosilicon compound is suitable as a wetter that enables high filling of a filler into silicone. In particular, even when an organic group such as an aryl group is introduced into the base silicone, the filler can be highly filled.

R ¹ is preferably an unsubstituted or substituted monovalent hydrocarbon group or an acyl group.

Such R ¹ is easy to synthesize and is preferable from the viewpoint of economy.

  Furthermore, it is preferable that j and k satisfy j + k = 1.

  If it is such j and k, the organosilicon compound of this invention will have an ester bond, it will be easy to synthesize | combine and it will become especially preferable from an economical viewpoint.

Further, m is preferably 1 or 2, and R ¹ is preferably a methyl group or an ethyl group.

Such m and R ¹ are particularly preferable from the viewpoints of ease of synthesis, economy, and reactivity.

  As described above, since the wettability of the filler with respect to silicone can be improved by blending the organosilicon compound of the present invention, the filler can be highly filled into silicone. For this reason, the thermally conductive silicone composition containing the organosilicon compound of the present invention can suppress an increase in viscosity and maintain fluidity even when the filler is highly filled. Furthermore, the organosilicon compound of the present invention can exhibit a sufficient effect even when an organic group such as an aryl group is introduced into the base silicone.

  Hereinafter, the present invention will be described in detail, but the present invention is not limited thereto. In the present invention, the part is an amount represented by “part by mass”, the viscosity and the kinematic viscosity are values at 25 ° C. “Me” represents a methyl group, and “Ph” represents a phenyl group.

  As a result of intensive studies, the present inventors have been able to highly fill a silicone with a filler if it is an organic silicon compound represented by the following general formula (1), and improve the wettability of the filler with respect to silicone. In particular, the present inventors have found that the present invention has a sufficient effect even when an organic group such as an aryl group is introduced into the base silicone.

（式中Ｒ^１は同一または異種の１価有機基であり、ｊおよびｋは０または１であり、ｍは１〜５の整数であり、ｎは６〜２０の整数である。） That is, this invention is an organosilicon compound characterized by being represented by the following general formula (1).

(In the formula, R ¹ is the same or different monovalent organic group, j and k are 0 or 1, m is an integer of 1 to 5, and n is an integer of 6 to 20.)

In the general formula (1), R ¹ is the same or different monovalent organic group and is not particularly limited as long as SiOR ¹ is hydrolyzable. Preferably, it is a monovalent organic group having 1 to 6 carbon atoms, more preferably 1 to 4, and still more preferably 1 to 3. More specifically, R ¹ is independently, for example, an unsubstituted or substituted monovalent hydrocarbon group, an acyl group, or the like, preferably having 1 to 6 carbon atoms, more preferably 1 to 4 carbon atoms. Preferably, it is a monovalent hydrocarbon group of 1 to 2, an acyl group or the like. When R ¹ is a monovalent hydrocarbon group, specific examples thereof include methyl group, ethyl group, propyl group, isopropyl group, butyl group, t-butyl group, pentyl group, hexyl group and other alkyl groups; cyclopentyl group And cycloalkyl groups such as cyclohexyl group; alkenyl groups such as vinyl group, allyl group and butenyl group; and aryl groups such as phenyl group. Further, when R ¹ is an acyl group, examples thereof include acyl groups such as an acetyl group, a propionyl group, an acryloyl group, and a methacryloyl group. Among these, an alkyl group having 1 to 4 carbon atoms is preferable, and a methyl group and an ethyl group are particularly preferable from the viewpoints of ease of synthesis, economy, and reactivity.

In said general formula (1), m is an integer of 1-5, Preferably it is 1-4, More preferably, it is an integer of 1-3. More specifically, examples of C _m H _{2m + 1} include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a t-butyl group, and a pentyl group. Among these, a methyl group and an ethyl group are particularly preferable from the viewpoint of ease of synthesis of the organosilicon compound of the present invention and economical efficiency.

In particular, m is preferably 1 or 2, and R ¹ is preferably a methyl group or an ethyl group. Such m and R ¹ are particularly preferable from the viewpoints of ease of synthesis, economy, and reactivity.

  In the general formula (1), j and k are 0 or 1, and preferably one of them is 0 and the other is 1, and j + k = 1 is satisfied. That is, the organosilicon compound of the present invention preferably has an ester bond.

  In said general formula (1), n is an integer of 6-20, Preferably it is an integer of 6-15, Most preferably, it is an integer of 8-12. If n is less than 6, the wetting (dispersibility improvement) effect is insufficient, and if it exceeds 20, synthesis may be difficult.

Specific examples of the organosilicon compound represented by the general formula (1) include the following compounds, but are not limited thereto.

  The organosilicon compound represented by the general formula (1) of the present invention is produced, for example, according to the following reaction formula.

（式中Ｒ^１、ｊ、ｋ、ｍおよびｎは前記の通りである。）

(Wherein R ¹ , j, k, m and n are as described above.)

  As shown in the above reaction formula, the organosilicon compound of the present invention is obtained by hydrosilylation reaction of an organic compound having a carbonyl group and an unsaturated group at the terminal and a silane compound having a hydrogen atom bonded to silicon. It is done. Here, the reaction molar ratio between the unsaturated group-containing organic compound and the silane compound having a hydrogen atom bonded to silicon is not particularly limited, but considering reaction efficiency, it is 1.5 / 1 to 1 / 1.5. In particular, the ratio is preferably 1.2 / 1 to 1 / 1.2.

  The above reaction is usually performed in the presence of a catalyst. Examples of the catalyst include platinum group metal catalysts conventionally known in hydrosilylation addition reactions, such as platinum, palladium and rhodium catalysts, and platinum catalysts are preferred. Platinum-based metal catalyst includes platinum black; solid platinum supported on a support such as alumina or silica; chloroplatinic acid, alcohol-modified chloroplatinic acid, complex of chloroplatinic acid and olefin; platinum and vinylsiloxane A complex etc. are mentioned. The amount of these used may be a so-called catalytic amount, and is usually 0.1 to 1000 ppm, preferably 1 to 1000 ppm in terms of platinum group metal with respect to the total amount of the acrylic group-containing alkoxysilane and hydrosilyl group-containing alkoxysilane. The amount is 100 ppm.

  The temperature of the above reaction may usually be room temperature to 200 ° C, preferably 30 to 120 ° C. The reaction time can be appropriately determined according to the production scale and the reaction temperature. In the above reaction, a solvent may not be used, and a solvent may be used as long as it does not adversely influence the reaction.

  The organosilicon compound of the present invention can be suitably applied as a wetter for a silicone composition containing a filler. As the silicone composition, curing types such as addition reaction curable silicone composition, organic peroxide curable silicone composition, condensation reaction curable silicone composition can be applied without limitation, and non-cured silicone grease and the like can be applied. It can also be applied to types of silicone compositions. Examples of fillers to be filled in the silicone composition include fumed silica, precipitated silica, quartz powder, alumina, aluminum hydroxide, boron nitride, aluminum nitride, silicon nitride, iron oxide, magnesium oxide, titanium oxide, zinc oxide, It can be applied to known fillers such as zirconium oxide, calcium carbonate, carbon black, graphite, aluminum, gold, silver, copper and nickel.

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

[Preparation Example 1] Preparation of platinum catalyst The reaction product of hexachloroplatinic acid and sym-tetramethyldivinyldisiloxane was diluted with toluene so that the platinum content was 0.5% by mass. A platinum catalyst (catalyst A) used in the comparative example was prepared.

[Example 1]
In a 1 liter four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a dropping funnel, 50.0 g (252 mmol) of methyl 10-undecenoate, 50.0 g of toluene, and 0.10 g of catalyst A were added and stirred. The temperature was raised to 75 ° C. Next, 37.0 g (303 mmol) of trimethoxysilane was added dropwise to the mixture with stirring. After the dropping, the reaction was carried out at a temperature of 80 ° C. for 3 hours. After completion of the reaction, unreacted raw materials and toluene were distilled off under reduced pressure to obtain 74.3 g (yield 92%) of the following product.

The above compound was identified by ¹ H NMR. NMR data is shown below. The corresponding hydrogen atom is underlined.
¹ H NMR (CDCl ₃ )
_{3.67ppm (s, 3H, C H} 3 O-)
3.52ppm (s, 9H, -Si ( OC H 3) 3)
2.25ppm (t, 2H, -COC H 2 -)
_{1.55ppm (tt, 2H, -COCH 2} C H 2 -)
1.34-1.17 ppm (br, 14 H , — (CH ₂ ) ₂ (C H ₂ ) ₇ CH ₂ Si≡)
0.60 ppm (t, 2H, -C H ₂ Si≡)

[Example 2]
In a 1 liter four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a dropping funnel, 50.0 g (235 mmol) of ethyl 10-undecenoate, 50.0 g of toluene, and 0.10 g of catalyst A were added and stirred. The temperature was raised to 75 ° C. Next, 34.5 g (282 mmol) of trimethoxysilane was added dropwise to the mixture with stirring. After the dropping, the reaction was carried out at a temperature of 80 ° C. for 3 hours. After completion of the reaction, unreacted raw materials and toluene were distilled off under reduced pressure to obtain 70.9 g (yield 90%) of the following product.

The above compound was identified by ¹ H NMR.
¹ H NMR (CDCl ₃ )
_{4.08ppm (q, 2H, CH 3} C H 2 -)
3.52ppm (s, 9H, -Si ( OC H 3) 3)
2.24ppm (t, 2H, -COC H 2 -)
_{1.57ppm (tt, 2H, -COCH 2} C H 2 -)
1.37 ppm (t, 3H, C H ₃ CH _2- )
1.35-1.16 ppm (br, 14H, — (CH ₂ ) ₂ (C H ₂ ) ₇ CH ₂ Si≡)
0.60 ppm (t, 2H, -C H ₂ Si≡)

[Example 3]
In a 1 liter four-necked flask equipped with a stirrer, a reflux condenser, a thermometer and a dropping funnel, 50.0 g (271 mmol) of acetic acid 8-nonenyl, 50.0 g of toluene, and 0.10 g of catalyst A were added and stirred. The temperature was raised to 75 ° C. Next, 39.7 g (325 mmol) of trimethoxysilane was added dropwise to the mixture with stirring. After the dropping, the reaction was carried out at a temperature of 80 ° C. for 3 hours. After completion of the reaction, unreacted raw materials and toluene were distilled off under reduced pressure to obtain 76.5 g (yield 92%) of the following product.

The above compound was identified by ¹ H NMR.
¹ H NMR (CDCl ₃ )
3.98 ppm (t, 2H, —OC H ₂ —)
3.50ppm (s, 9H, -Si ( OC H 3) 3)
1.98 ppm (s, 3H, C H ₃ CO-)
_{1.55ppm (tt, 2H, -OCH 2} C H 2 -)
1.44-1.23 ppm (br, 12H, — (CH ₂ ) ₂ (C H ₂ ) ₆ CH ₂ Si≡)
0.58 ppm (t, 2H, -C H ₂ Si≡)

[Application examples 1 and 2]
Next, the following components (A) to (C) for forming a composition containing the organosilicon compound of the present invention were prepared.

(A) Organopolysiloxane A-1: Organopolysiloxane represented by the following formula (6) and having a viscosity of 2.0 Pa · s

(B) Silane coupling agent (wetter)
B-1: Organosilicon compound represented by the following formula (7) B-2: Organosilicon compound represented by the following formula (4) (synthesized in Example 2)

(C) Filler C-1: Alumina powder (average particle size 10.0 μm)
C-2: Alumina powder (average particle size 1.5 μm)

[Method for producing composition containing organosilicon compound]
The components (A) to (C) were mixed as shown in Table 1 to obtain compositions of Application Examples 1 and 2 and Comparative Examples 1 and 2. That is, each component was weighed at the composition ratio (parts by mass) shown in Table 1 and mixed using a rotation / revolution mixer (manufactured by Shinky Corporation). The obtained composition was cooled to room temperature.

〔Test method〕
Thereafter, the obtained composition was allowed to stand in a thermostatic chamber at 25 ° C. for 24 hours, and then the viscosity at a rotational speed of 5 rpm was measured using a rotational viscometer. The results are shown in Table 1.

  As shown in Table 1, in Comparative Examples 1 and 2 that do not contain the organosilicon compound of the present invention, when the filler is highly filled, the viscosity becomes high, the fluidity of the heat conductive material is remarkably lowered, and the coating property (dispensing) From the viewpoints of properties, screen printability, etc. In contrast, Application Examples 1 and 2 show that the organosilicon compound of the present invention can suppress an increase in the viscosity of the composition and is suitable as a wetter capable of highly filling the filler.

The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

Claims (3)

An organosilicon compound represented by the following general formula (1);

(Wherein R ¹ is the same or different monovalent organic group, j = 0, k = 1 , j + k = 1, m is an integer of 1 to 5, and n is an integer of 6 to 20) .)
Silicone having an aryl group as a base polymer;
Look contains a filler, the filler is precipitated silica, quartz powder, alumina, aluminum hydroxide, boron nitride, titanium oxide, zinc oxide, aluminum, gold, silver, that is either copper and nickel A heat conductive silicone composition characterized by the above. 2. The thermally conductive silicone composition according to claim 1, wherein R ¹ is an unsubstituted or substituted monovalent hydrocarbon group or an acyl group. 3. The thermally conductive silicone composition according to claim 1, wherein m is 1 or 2, and R ¹ is a methyl group or an ethyl group.