Organopolysiloxane

Abstract

To provide novel organopolysiloxane acting as a wetter to allow phenyl modified silicone to be highly filled with a high thermal conductive filler.SOLUTION: The present invention provides organopolysiloxane represented by a general formula (1). (In the formula, each R1 independently represents a C6-10 monovalent aromatic hydrocarbon group, each R2 independently represents a C1-10 alkyl group, R3 represents a C1-4 alkyl group, a is 2 or 3, m is an integer satisfying 1≤m≤30, and n is an integer satisfying 0≤n≤60, provided that the range 3≤m+n≤90 is satisfied. Boding of each siloxane unit in brackets in the general formula (1) may be a block or random.)SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to organopolysiloxanes. [Background technology]

[0002] Electronic components such as CPUs, which are highly integrated circuits, experience a significant decrease in performance due to the heat generated during use. To solve this problem, heat dissipation materials are used to improve heat transfer efficiency by being introduced into the air layer between the heat-generating and cooling parts. Among these, silicone heat dissipation materials are widely used in various fields due to their high heat resistance, weather resistance, and electrical insulation properties derived from silicone. Furthermore, in recent years, electronic devices have become smaller and more highly integrated, making it crucial to cool the heat they generate more efficiently. Therefore, there is a demand for heat dissipation materials with high thermal conductivity.

[0003] The thermal conductivity of a material containing silicone oil and a thermally conductive filler is affected by the thermal conductivity of the thermally conductive filler itself when its volume fraction exceeds 0.6. Therefore, to increase the thermal conductivity of a heat dissipation material, it is important to increase the density of the thermally conductive filler. However, simply increasing the density significantly reduces the fluidity of the conductive grease, resulting in poor processability. To solve this problem, a method has been proposed in which the thermally conductive filler is surface-treated with a silane coupling agent (wetter) to disperse it in the silicone base oil, thereby maintaining the fluidity of the thermally conductive grease.

[0004] Phenyl-modified silicone, which has a structure where part of the methyl silicone is replaced by a phenyl group, has heat resistance, cold resistance, and oxidation resistance compared to methyl silicone. Furthermore, due to its high gas barrier property and high refractive index, phenyl-modified silicone is applied to cosmetics, encapsulating materials for light-emitting diodes, etc. (Patent Documents 1, 2). Therefore, it is considered that by using phenyl-modified silicone as a base oil and applying it to a heat dissipation material, properties that cannot be achieved with methyl silicone can be realized. On the other hand, since the silicone skeleton becomes rigid due to the introduction of a phenyl group, there is a problem that the viscosity significantly increases, especially in high phenyl-modified silicone (Patent Document 3).

[0005] Therefore, when a heat conductive filler is filled into phenyl-modified silicone to form a grease, the fluidity of the heat conductive grease significantly deteriorates. In addition, organopolysiloxane having a trialkoxysilyl group, which is often used as a wetter, has poor solubility in phenyl-modified silicone (Patent Documents 4, 5). Therefore, there has been a demand for the development of a wetter that shows high solubility in phenyl-modified silicone and suppresses an increase in viscosity when filled with a heat conductive filler.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Disclosure of the Invention

Problems to be Solved by the Invention

[0007] An object of the present invention is to provide a novel organopolysiloxane that acts as a wetter capable of highly filling a resin material, particularly phenyl-modified silicone, with a high thermal conductivity filler.

Means for Solving the Problems

[0008] In order to achieve the above object, the present invention provides the following novel organopolysiloxane.

[0009] That is, the present invention provides an organopolysiloxane represented by the following general formula (1):

Chemical formula

[0010] Such an organopolysiloxane is suitable as a wetter, and for example, it can highly fill a phenyl-modified silicone with a high thermal conductivity filler.

[0011] It is preferable that the above organopolysiloxane is represented by the following general formula (2).

Chemical formula

[0012] Such organopolysiloxanes exhibit high solubility due to phenyl-modified silicones.

[0013] The R shown in the above general formulas (1) and (2) 1 R is a phenyl group, 2 It is preferable that it be a methyl group. These groups are preferable from the viewpoint of organopolysiloxane synthesis.

[0014] The present invention provides a wetter comprising the organopolysiloxane described above. By using the organopolysiloxane described above as a wetter, the thermally conductive filler can be more effectively dispersed in the phenyl-modified silicone. [Effects of the Invention]

[0015] The organopolysiloxane of the present invention is useful as a silane coupling agent (wetter) that improves the dispersibility of thermally conductive fillers in phenyl-modified silicone. Therefore, even when a phenyl-modified silicone composition containing the organopolysiloxane of the present invention contains a large amount of thermally conductive filler, the viscosity of the composition is suppressed and fluidity is maintained. Thus, when the organopolysiloxane of the present invention is introduced into a silicone composition, a thermally conductive silicone composition can be obtained in which viscosity increase is suppressed even when the thermally conductive filler is highly packed. [Brief explanation of the drawing]

[0016] [Figure 1]29Si-NMR chart of the organopolysiloxane synthesized in Example 1.

Mode for Carrying Out the Invention

[0017] The inventors of the present invention searched for an organopolysiloxane suitable as a wetter that enables high filling of a resin material, particularly phenyl-modified silicone, with a highly thermally conductive filler, and found that those represented by the following general formula (1) are useful, thus completing the present invention. That is, the present invention provides an organopolysiloxane represented by the following general formula (1)

Chemical formula

Chemical formula

[0018] The present invention will be described in detail below.

[0019] In the above general formula (1), R 1 R is an independent monovalent aromatic hydrocarbon group having 6 to 10 carbon atoms. 1 Specific examples include aryl groups such as phenyl, tolyl, xylyl, and mesityl groups, with the phenyl group being preferred from the viewpoint of ease of synthesis.

[0020] In the above general formula (1), R 2 R is an alkyl group having 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, more preferably 1 to 3 carbon atoms. 2 Examples of these groups include methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, pentyl, hexyl, octyl, nonyl, and decyl groups, among which methyl or ethyl groups are preferred from the viewpoint of ease of synthesis.

[0021] In the above general formula (1), R 3 R is independently an alkyl group having 1 to 4 carbon atoms, preferably a methyl group or an ethyl group. 3 Examples of these groups include methyl, ethyl, propyl, isopropyl, butyl, and tert-butyl groups. Among these, methyl and ethyl groups are particularly preferred from the viewpoint of the hydrolysis properties of the organopolysiloxane compound of the present invention. In addition, in the above general formula (1), a is 2 or 3, but from the viewpoint of ease of synthesis and economic efficiency, a is preferably 3.

[0022] In the above general formula (1), m is usually an integer between 1 ≤ m ≤ 30, preferably 3 ≤ m ≤ 20, and more preferably 5 ≤ m ≤ 18. If m exceeds 30, the viscosity of the organopolysiloxane increases significantly, which is undesirable. Also, in the above general formula (1), n ​​is usually an integer between 0 ≤ n ≤ 60, preferably 5 ≤ n ≤ 50, and more preferably 10 ≤ n ≤ 40. Outside this range, the compatibility with phenyl-modified silicone decreases, which is undesirable. Furthermore, m + n is between 3 ≤ m + n ≤ 90, and preferably 6 ≤ m + n ≤ 60. Outside this range, the handling of the product during the synthesis of this compound becomes poor, which is undesirable. Furthermore, the siloxane units enclosed in parentheses in general formula (1) may be linked in a block or randomly.

[0023] Specific examples of organopolysiloxanes represented by the general formula (1) above include, but are not limited to, the following compounds. In the formulas shown below, "Me" represents a methyl group and "Ph" represents a phenyl group. [ka]

[0024] The organopolysiloxane represented by the above general formula (1) can be synthesized, for example, as shown in the following reaction equation.

[0025] Reaction equation: [ka]

[0026] In the formula, m and n are 29 Identified by Si-NMR

[0027] Organopolysiloxane compounds as shown in the general formula (1) above are synthesized by heating and stirring silanol and 1,1-diphenyl-3,3,5,5-tetramethyltrisiloxane (hereinafter sometimes referred to as phenyl-modified cyclic siloxane) in acetonitrile solvent in the presence of a bis(1,2-benzenediolate)phenyl silicate sodium salt (NAS, above formula) catalyst, and then reacting with ethyl 2-(trimethoxysilyl)propionate (ECMS, above formula) as a reaction stopper. Polar solvents such as acetonitrile (MeCN) or N,N-dimethylformamide (DMF) are preferred as the solvent for this reaction. The reaction temperature is usually 60-65°C, and the reaction time for each step is approximately 2 hours.

[0028] By changing the equivalent amount of phenyl-modified cyclic siloxane relative to silanol, the length of the main chain (m+n) of the organopolysiloxane compound, i.e., the degree of polymerization, can be adjusted.

[0029] The resulting organopolysiloxane exhibits high solubility in phenyl-modified silicone.

[0030] The phenyl-modified silicone composition containing the above organopolysiloxane of the present invention can be highly filled while maintaining the dispersibility of the thermally conductive filler, and is therefore suitable for use as a wetter. [Examples]

[0031] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In the following examples, the kinematic viscosity is the value measured at 25°C using a Cannon-Fenske viscometer as described in JIS Z8803::2011. The refractive index is the value measured at 25°C using an Abbe refractometer as described in JIS K0062:1992. D This is the value of . Also, in the formula below, Me represents a methyl group and Ph represents a phenyl group.

[0032] [Example 1] A 300 mL round-neck separable flask was equipped with a stirrer, thermometer, and condenser via a four-neck separable cover. Trimethylsilanol (9.0 g, 0.1 mol), phenyl-modified cyclic siloxane (103.8 g, 0.3 mol), and acetonitrile (60.8 g) were added to this separable flask, and the mixture was heated and stirred at 65°C to dissolve the phenyl-modified cyclic siloxane. After the phenyl-modified cyclic siloxane was completely dissolved, NAS (61 mg, 0.0178 mmol) was added, and the reaction solution was heated and stirred at 65°C for 2 hours. The reaction proceeded as follows: 1 After tracking the reaction using 1H-NMR spectroscopy and confirming the disappearance of the signal for the phenyl-modified cyclic siloxane, the reaction stopper ECMS (29.1 g, 0.13 mol) was added, and the mixture was heated and stirred at 65°C for 2 hours. After confirming the disappearance of the peak corresponding to the silanol by infrared spectroscopy, methanol was added to the reaction solution, and the mixture was heated and stirred at 65°C for 1 hour. After the reaction mixture was allowed to return to room temperature, it was washed with methanol, and the oil layer was extracted. The solvent and low molecular weight siloxane contained in the obtained oil layer were removed under reduced pressure to obtain the organopolysiloxane compound. This compound is a colorless, transparent liquid with a kinematic viscosity of 314 mmHg. 2 ·s ―1 The refractive index was 1.505. Also, 29 Si-NMR spectroscopy revealed that it has the following structure (NMR chart shown in Figure 1). 29 Si-NMR spectrum (99.37 MHz, CDCl3, 25°C): δ = 7.9 (SiMe3), -17.8 to -21.1 (SiMe2), -46.7 to -47.8 (SiPh2), -84.7 to -85.0 (Si(OMe)3) [ka]

[0033] [Example 2] An organopolysiloxane compound was obtained using the same method as described above, except that 5 equivalents of phenyl-modified cyclic siloxane were used relative to trimethylsilanol. This compound is a colorless, transparent liquid with a kinematic viscosity of 552 mmHg. 2 ·s-1 The refractive index was 1.509. Also, 29 Si-NMR spectroscopy revealed that it has the following structure. [ka] 29 Si-NMR spectrum (99.37 MHz, CDCl3, 25°C): δ = 7.9 (SiMe3), -17.8 to -21.3 (SiMe2), -46.7 to -47.7 (SiPh2), -84.7 to -85.0 (Si(OMe)3).

[0034] [Example 3] An organopolysiloxane compound was obtained using the same method as described above, except that 10 equivalents of phenyl-modified cyclic siloxane were used relative to trimethylsilanol. This compound is a colorless, transparent liquid with a kinematic viscosity of 1255 mmHg. 2 ·s -1 The refractive index was 1.512. Also, 29 Si-NMR spectroscopy revealed that it has the following structure. [ka] 29 Si-NMR spectrum (99.37 MHz, CDCl3, 25°C): δ = 7.9 (SiMe3), -17.8 to -21.3 (SiMe2), -46.7 to -47.7 (SiPh2), -84.7 to -85.0 (Si(OMe)3).

[0035] [Example 4] An organopolysiloxane compound was obtained using the same method as described above, except that 15 equivalents of phenyl-modified cyclic siloxane were used relative to trimethylsilanol. This compound is a colorless, transparent liquid with a kinematic viscosity of 2158 mmHg. 2 ·s -1 The refractive index was 1.515. Also, 29 Si-NMR spectroscopy revealed that it has the following structure. [ka] 29 Si-NMR spectrum (99.37MHz, CDCl3, 25℃): δ=7.9 (SiMe3), -17.6~-21.3 (SiMe2), -47.0~-48.0 (SiPh2), -84.7 to -85.0 (Si(OMe)3).

[0036] [Compatibility Test] When the following organosiloxane (B-6) is dispersed at 25% in phenyl-modified silicone, turbidity and layer separation occur. On the other hand, when the above novel organosiloxane is dispersed under the same conditions, turbidity and layer separation do not occur, indicating that the above novel organosiloxane exhibits high compatibility with phenyl-modified silicone.

[0037] The components described below were mixed with components (A) to (C) in the composition ratios shown in Tables 1 and 2 to obtain the compositions of Examples 5 to 11 and Comparative Examples 1 to 4.

[0038] [Example 5] A thermally conductive phenyl-modified silicone composition was obtained by mixing component (A) A-1, component (B) B-1, and component (C). The mixing was performed by placing plastic containers containing components (A) to (C) into a rotation-revolution type mixer (product name: Awatori Rentaro, manufactured by THINKY Co., Ltd.), mixing at room temperature at 2,000 rpm for 1 minute twice, and then cooling the resulting mixture to room temperature before measuring its viscosity.

[0039] [Example 6] A thermally conductive phenyl-modified silicone composition was prepared in the same manner as in Example 5 by changing component (B) from B-1 to B-2, and viscosity measurements were performed.

[0040] [Example 7] (B) A thermally conductive phenyl-modified silicone composition was prepared in the same manner as in Example 5 by changing component B-1 to B-3, and viscosity measurements were performed.

[0041] [Example 8] (B) A thermally conductive phenyl-modified silicone composition was prepared in the same manner as in Example 5 by changing component B-1 to B-4, and viscosity measurements were performed.

[0042] [Comparative Example 1] (B) The composition of Comparative Example 1 was prepared in the same manner as in Example 5, with component B changed from B-1 to B-5, and viscosity measurements were performed.

[0043] [Comparative Example 2] (B) The composition of Comparative Example 2 was prepared in the same manner as in Example 5, with component B changed from B-1 to B-6, and viscosity measurements were performed.

[0044] [Example 9] A thermally conductive phenyl-modified silicone composition was prepared in the same manner as in Example 5, by changing component (A) from A-1 to A-2 and component (B) from B-1 to B-2, and viscosity measurements were performed.

[0045] [Example 10] A thermally conductive phenyl-modified silicone composition was prepared in the same manner as in Example 5, by changing component (A) from A-1 to A-3 and component (B) from B-1 to B-2, and viscosity measurements were performed.

[0046] [Example 11] A thermally conductive phenyl-modified silicone composition was prepared in the same manner as in Example 5 by changing the composition and content of component (B) from B-1 to B-2 and component (C) (C-1 was changed to C-4), and viscosity measurements were performed.

[0047] [Comparative Example 3] (A) In addition to A-1, A-2 was added as component (A), and component (B) was omitted. The composition of Comparative Example 3 was prepared in the same manner as in Example 5, and viscosity measurements were performed.

[0048] [Comparative Example 4] Without adding component (B), the composition of Comparative Example 4 was prepared in the same manner as in Example 5, by changing the content of component (C), and the viscosity was measured.

[0049] (A) Organosiloxane A-1: Expressed by the following formula, when the kinematic viscosity is 700 mm2 ·s -1 organosiloxane [ka]

[0050] A-2: Expressed by the following formula, where the kinematic viscosity is 380 mm 2 ·s -1 Phenyl-modified organosiloxane [ka]

[0051] A-3: Expressed by the following formula, when the kinematic viscosity is 2,000 mm 2 ·s -1 Phenyl-modified organosiloxane [ka]

[0052] (B) Wetter B-1: Organosiloxane synthesized in Example 1, represented by the following formula. [ka]

[0053] B-2: Organosiloxane synthesized in Example 2, represented by the following formula. [ka]

[0054] B-3: Organosiloxane synthesized in Example 3, represented by the following formula. [ka]

[0055] B-4: Organosiloxane synthesized in Example 4, represented by the following formula. [ka]

[0056] B-5: Organosiloxane of Comparative Example 1, represented by the following formula [ka]

[0057] B-6: Organosiloxane represented by the following formula [ka]

[0058] (C) Thermally conductive filler C-1: Spherical alumina powder (average particle size 45 μm) C-2: Spherical alumina powder (average particle size 10 μm) C-3: Amorphous alumina powder (average particle size 2 μm) C-4: Amorphous aluminum nitride powder (average particle size 30 μm)

[0059] [Manufacturing method] The compositions of the example composition and comparative example were obtained by mixing components (A) to (C) as follows. Components (A) to (C) were weighed out and placed in plastic containers in a rotary / revolving mixer (product name: Awatori Rentaro, manufactured by THINKY Co., Ltd.) in the composition ratio (volume) shown in Table 1. The mixture was mixed at room temperature at 2,000 rpm for 1 minute twice, and the resulting mixture was then cooled to room temperature.

[0060] [Test Method] The properties of the obtained compositions were measured using the following test methods. The results are shown in the table below.

[0061] [Viscosity measurement] The obtained composition was measured using a viscosity and viscoelasticity measuring device (product name: MARS40 (Thermo Fisher Scientific Co., Ltd.)) at a rotation speed of 10s. -1 The viscosity was measured using the viscometer. The measurement conditions were 23°C, using a parallel plate, and a gap of 0.5 mm.

[0062] [Table 1]

[0063] [Table 2]

[0064] The results in Tables 1 and 2 show that the phenyl-modified silicone composition containing organopolysiloxane of the present invention has a reduced viscosity, allowing for high-density filling of thermally conductive fillers. In particular, in Example 10, despite using the high-viscosity A-3 as component A, the viscosity of the composition was reduced compared to Comparative Example 1. On the other hand, when B-5, which is not included in the range shown in general formula (2), was used (Comparative Example 1), and when the composition did not contain component (B) (Comparative Examples 3 and 4), the viscosity increased. Furthermore, when B-6, which does not contain a phenyl group, was used (Comparative Example 2), the viscosity of the composition did not increase.

[0065] This specification includes the following embodiments: [1]: An organopolysiloxane characterized by being represented by the following general formula (1). [ka] (In the formula, R 1 R is an independent monovalent aromatic hydrocarbon group having 6 to 10 carbon atoms. 2 R is an alkyl group having 1 to 10 carbon atoms, and 3 is an alkyl group having 1 to 4 carbon atoms. a is 2 or 3, m is an integer between 1 ≤ m ≤ 30, and n is an integer between 0 ≤ n ≤ 60, provided that 3 ≤ m + n ≤ 90. The bonding of the siloxane units enclosed in parentheses in general formula (1) may be in a block or random. [2]: The organopolysiloxane of [1], characterized in that the organopolysiloxane is represented by the following general formula (2). [ka] (In the formula, R 1 , R 2 , R 3 And a are the same as above, x is an integer between 1 ≤ x ≤ 30, m' is an integer between 1 ≤ m' ≤ 3, and n' is an integer between 0 ≤ n' ≤ 2, where m' + n' is 3. The bonding of siloxane units enclosed in parentheses in the above general formula (2) may be block or random, and the bonding of two types of siloxane units enclosed in parentheses with x is a block polymer. [3]: In the above general formulas (1) and (2), R 1 is a phenyl group, R 2 The organopolysiloxane according to [1] or [2], characterized in that the group is a methyl group. [4]: A wetter comprising the organopolysiloxane described in any of [1] to [3] above.

[0066] It should be noted that the present invention is not limited to the embodiments described above. The embodiments described above are illustrative, and any configuration that is substantially identical to the technical idea described in the claims of the present invention and achieves similar effects is included within the technical scope of the present invention.

Claims

1. The following general formula (2) 【Chemistry 1】 (In the formula, R １ R is an independent monovalent aromatic hydrocarbon group having 6 to 10 carbon atoms. ２ R is an alkyl group having 1 to 10 carbon atoms, ３ is an alkyl group having 1 to 4 carbon atoms. a is 2 or 3, x is an integer between 1 and 30, m' is an integer between 1 and 2, and n' is an integer between 1 and 2, where m' + n' is 3. The bonds between the siloxane units enclosed in parentheses with m' and n' may be block or random, and the bonds between the two types of siloxane units enclosed in parentheses with x are block polymers. An organopolysiloxane characterized by being represented by [the formula shown].

2. The aforementioned R １ is a phenyl group, and the R ２ The organopolysiloxane according to claim 1, characterized in that the group is a methyl group.

3. A wetter comprising the organopolysiloxane according to claim 1 or claim 2.

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