Thermally conductive silicone composition

Patent metadata

Field	Value
Publication number	US-2024218150-A1
Application number	US-202218563419-A
Country	US
Kind code	A1
Filing date	Mar 31, 2022
Priority date	May 26, 2021
Publication date	Jul 4, 2024
Grant date	—

Abstract

[Problem]
One object of the present invention is to provide a thermally conductive silicone composition in which an increase in viscosity is suppressed when a thermally conductive filler is filled with a high amount level, and a thermally conductive silicone cured product having good thermal conductivity and excellent handling properties.
[Solution]
A thermally conductive silicone composition comprising the following components (A) to (F): (A) an organopolysiloxane having at least two alkenyl groups each bonded to a silicon atom: 100 parts by mass; (B) an organohydrogenpolysiloxane having at least two hydrogen atoms each bonded to a silicon atom in an amount such that a ratio of the number of the hydrogen atom bonded to a silicon atom to the number of the alkenyl group in component (A) is 0.1 to 2; (C) a thermally conductive filler: 4,000 to 7,000 parts by mass; (D) a platinum group metal-based catalyst: a catalyst amount; (E) an addition reaction control agent: 0.01 to 1 part by mass; and (F) a dimethylpolysiloxane having a trialkoxysilyl group at one end of a molecular chain and represented by the formula (1): 100 to 300 parts by mass: wherein R 5 is, independently of each other, an alkyl group having 1 to 6 carbon atoms and c is an integer of 5 to 100, wherein the thermally conductive filler (C) comprises, relative to a total mass of component (C), 20 to 50 mass % of aluminum nitride (C1) having a volume median diameter in the range of 50 μm or more and less than 120 μm, 20 to 40 mass % of alumina (C2) having a volume median diameter in the range of 1 μm or more and less than 5 μm, and 2 to 10 mass % of alumina (C3) having a volume median diameter in the range of 0.1 μm or more and less than 1 μm.

First claim

1 . A thermally conductive silicone composition comprising the following components (A) to (F):
(A) an organopolysiloxane having at least two alkenyl groups each bonded to a silicon atom: 100 parts by mass; (B) an organohydrogenpolysiloxane having at least two hydrogen atoms each bonded to a silicon atom in an amount such that a ratio of the number of the hydrogen atom bonded to a silicon atom to the number of the alkenyl group in component (A) is 0.1 to 2; (C) a thermally conductive filler: 4,000 to 7,000 parts by mass; (D) a platinum group metal-based catalyst: a catalyst amount; (E) an addition reaction control agent: 0.01 to 1 part by mass; and (F) a dimethylpolysiloxane having a trialkoxysilyl group at one end of a molecular chain and represented by the following formula (1): 100 to 300 parts by mass:

wherein R 5 is, independently of each other, an alkyl group having 1 to 6 carbon atoms and c is an integer of 5 to 100,
wherein the thermally conductive filler (C) comprises, relative to a total mass of component (C), 20 to 50 mass % of aluminum nitride (C1) having a volume median diameter in the range of 50 μm or more and less than 120 μm, 20 to 40 mass % of alumina (C2) having a volume median diameter in the range of 1 μm or more and less than 5 μm, and 2 to 10 mass % of alumina (C3) having a volume median diameter in the range of 0.1 μm or more and less than 1 μm.

2 . The thermally conductive silicone composition according to claim 1 , further comprising 1 to 30 parts by mass of (G) an organopolysiloxane represented by the following general formula (2):
R 6 —(SiR 6 2 O) d SiR 6 3   (2)
wherein R 6 is, independently of each other, a monovalent hydrocarbon group having 1 to 8 carbon atoms, free from an aliphatic unsaturated bond, and d is an integer of 5 to 2,000, and having a kinematic viscosity at 25° C. of 10 to 100,000 mm 2 /s.

3 . The thermally conductive silicone composition according to claim 1 , further comprising alumina (C4) having a volume median diameter in the range of 5 μm or more to 100 μm or less in an amount of 58 mass % or less, relative to the total mass of component (C).

4 . The thermally conductive silicone composition according to claim 1 , wherein component (C1) is a crushed aluminum nitride.

5 . The thermally conductive silicone composition according to claim 1 , wherein component (C2) is at least one selected from a spherical alumina and a crushed alumina.

6 . The thermally conductive silicone composition according to claim 1 , wherein component (C3) is a spherical alumina.

7 . The thermally conductive silicone composition according to claim 1 , having a viscosity of 3,000 Pas or less.

8 . A cured product composed of curing the thermally conductive silicone composition according to claim 1 .

9 . The cured product according to claim 8 , having a thermal conductivity of 8.5 W/m·K or more.

10 . A thermally-conductive heat-dissipating silicone sheet comprising a PET film and the cured product according to claim 8 .

11 . The thermally conductive silicone composition according to claim 2 , further comprising alumina (C4) having a volume median diameter in the range of 5 μm or more to 100 μm or less in an amount of 58 mass % or less, relative to the total mass of component (C).

12 . The thermally conductive silicone composition according to claim 2 , wherein component (C1) is a crushed aluminum nitride.

13 . The thermally conductive silicone composition according to claim 2 , wherein component (C2) is at least one selected from a spherical alumina and a crushed alumina.

14 . The thermally conductive silicone composition according to claim 2 , wherein component (C3) is a spherical alumina.

15 . The thermally conductive silicone composition according to claim 2 , having a viscosity of 3,000 Pa·s or less.

16 . A cured product composed of curing the thermally conductive silicone composition according to claim 2 .

17 . The cured product according to claim 16 , having a thermal conductivity of 8.5 W/m·K or more.

18 . A thermally-conductive heat-dissipating silicone sheet comprising a PET film and the cured product according to claim 16 .

19 . The thermally conductive silicone composition according to claim 3 , wherein component (C1) is a crushed aluminum nitride.

20 . The thermally conductive silicone composition according to claim 3 , wherein component (C2) is at least one selected from a spherical alumina and a crushed alumina.

Assignees

• Shinetsu Chemical Co

Inventors

• Ito Takanori
• Miyano Megumi
• Tsukada Junichi
• Ishihara Yasuhisa
• Endo Akihiro
• HIRONAKA Yuya

Classifications

• C08G77/20

  containing silicon bound to unsaturated aliphatic groups · CPC title

• C08G77/12

  containing silicon bound to hydrogen · CPC title

• C08L83/04 Primary

  Polysiloxanes · CPC title

• C08K2201/001

  Conductive additives · CPC title

• C08K2201/014

  Additives containing two or more different additives of the same subgroup in C08K · CPC title