US 12,359,038 B2
Highly thermally conductive flowable silicone composition
Yan Zheng, Shanghai (CN); Chen Chen, Shanghai (CN); Dorab Bhagwagar, Auburn, MI (US); Peng Wei, Shanghai (CN); and Qianqing Ge, Shanghai (CN)
Assigned to Dow Silicones Corporation, Midland, MI (US)
Appl. No. 17/761,360
Filed by Dow Silicones Corporation, Midland, MI (US)
PCT Filed Dec. 5, 2019, PCT No. PCT/CN2019/123175
§ 371(c)(1), (2) Date Mar. 17, 2022,
PCT Pub. No. WO2021/109051, PCT Pub. Date Jun. 10, 2021.
Prior Publication US 2022/0289936 A1, Sep. 15, 2022
Int. Cl. C08K 3/22 (2006.01); C08G 77/04 (2006.01); C08K 3/28 (2006.01)
CPC C08K 3/22 (2013.01) [C08G 77/04 (2013.01); C08K 3/28 (2013.01); C08K 2003/2227 (2013.01); C08K 2003/282 (2013.01); C08K 2201/001 (2013.01); C08K 2201/005 (2013.01)] 10 Claims
 
1. A composition comprising:
a. 2.5-4.0 weight-percent of a polyorganosiloxane component comprising:
i. a trialkoxysiloxy-terminated diorganopolylsiloxane having Formula (I) where Vi refers to vinyl group, R in each occurrence is methyl and subscript a is a value in a range of 50 to 60:
ViR2SiO—(R2SiO)a—SiR2Vi  (I)
ii. a trimethylsiloxy-terminated dimethyl siloxane methylhydrogen siloxane having Formula (II) where b has a value in a range of 5 to 25, c has a value in a range of one to 5:
(CH3)3Si—((CH3)2SiO)b˜((CH3)HSiO)c—Si(CH3)3  (II);
b. a filler treating agent comprising:
i. 0.20-0.26 wt % of an alkyltrialkoxysilane having the general formula (R′)(R″O)3Si where R′ is an alkyl having 8 or more and at the same time 12 or fewer carbon atom on average per molecule and R″ is methyl; and
ii. 0-1.2 wt % of a trialkoxysiloxy-terminated diorganopolysiloxane having the general formula R3SiO—(R2SiO)d—[(CH2)e((CH3)2SiO)f]g—(CH2)e—Si(OR″)3 where each R and R″ are methyl groups, d is a value in a range of 25-35, and e and g are zero;
c. 90-98 weight-percent of a combination of thermally conductive fillers comprising:
i. 25-40 weight-percent of thermally conductive filler particles having an average particle size of 70-120 micrometers and selected from one or a combination of aluminum oxide and aluminum nitride particles;
ii. 15-30 weight-percent thermally conductive filler particles having an average particle size in a range of 30-45 micrometers selected from one or a combination of aluminum oxide and aluminum nitride particles;
iii. 25-32 weight-percent aluminum oxide particles having an average particle size in a range of 1-3 micrometers; and
iv. 10-15 weight-percent aluminum oxide thermally conductive filler particles having an average particle size in a range of 0.1 to 0.5 micrometers;
where weight-percent is relative to composition weight.