Heat-conductive silicone composition
View Patent ↗A heat-conductive silicone composition comprising at least (A) an organopolysiloxane, (B) a heat-conductive filler, and (C) a specific organosiloxane. The silicone composition is excellent in handleability, even when it contains a large amount of a heat-conductive filler for the purpose of attaining higher heat conductivity.
1. A thermally conductive silicone composition comprising:
(A) an organopolysiloxane,
(B) a thermally conductive filler comprising a metal powder, a metal oxide powder, a metal nitride powder, a metal carbide powder, a soft magnetic alloy powder, a ferrite, and combinations thereof, and
(C) at least one organosiloxane selected from the group consisting of
(i) an organosiloxane represented by the general formula:
[R 1 a R 2 (3−a) SiO(R 1 b R 2 (2−b) SiO) m (R 2 2 SiO) n ] c SiR 2 [4−(c+d)] (OR 3 ) d
where R 1 stand for monovalent hydrocarbon groups having aliphatic unsaturated bonds, R 2 stand for identical or different monovalent hydrocarbon groups having no aliphatic unsaturated bonds, R 3 is selected from a group consisting of an alkyl, alkoxyalkyl, alkenyl, and acyl, the subscript a is an integer of 0 to 3, b is 1 or 2, c is an integer of 1 to 3, d is an integer of 1 to 3, c+d is an integer of 2 to 4, m is an integer of 0 or greater, and n is integer of from 10 to 100, with the proviso that m is an integer of 1 or greater when a is 0,
(iii) an organosiloxane represented by the general formula:
where R 4 is identical or different monovalent hydrocarbon groups, R 5 is an oxygen atom or divalent hydrocarbon group, R 3 is the same as defined above, p is an integer of 105 to 200, and d is the same as above, and
(iv) an organosiloxane represented by the general formula:
[H e R 2 (3−e) SiO(R 2 2 SiO) n ] c SiR 2 [4−(c+d)] ( 0 R 3 ) d
where R 2 , R 3 , c,d and n are the same as defined above, and e is an integer of 1 to 3.
2. The thermally conductive silicone composition according to claim 1 , in which the average particle size of Component (B) is 0.1 to 100 μm.
3. The thermally conductive silicone composition according to claim 1 , in which Component (B) is an alumina powder.
4. The thermally conductive silicone composition according to claim 3 , in which Component (B) is a mixture of (B 1 ) a spherical alumina powder with an average particle size of greater than 5 to 50 μm and (B 2 ) a spherical or inegular-shaped alumina powder with an average particle size of 0.1 to 5 μm.
5. The thermally conductive silicone composition according to claim 4 , in which Component (B) is made up of 30 to 90 wt % of component (B 1 ) and 10 to 70 wt % of component (B 2 ).
6. The thermally conductive silicone composition according to claim 1 , in which the content of Component (B) is 500 to 2,500 parts by weight per 100 parts by weight of Component (A).
7. The thermally conductive silicone composition according to claim 1 , in which the content of Component (C) is 0.1 to 10 parts by weight per 100 parts by weight of Component (B).
8. The thermally conductive silicone composition according to claim 1 , in which Component (B) is surface-treated with Component (C) in Component (A).
9. The thermally conductive silicone composition according to claim 1 , in which the thermally conductive silicone composition further contains (D) a curing agent and is curable.
10. The thermally conductive silicone composition according to claim 9 , in which the thermally conductive silicone composition is curable by means selected from the group consisting of (i) a hydrosilation reaction, (ii) condensation reaction, and (iii) an organic peroxide-induced free radical reaction.
11. The thermally conductive silicone composition according to claim 9 , in which the thermally conductive silicone composition is curable by means of a hydrosilation reaction.
12. The thermally conductive silicone composition according to claim 1 , in which Component (A) has a viscosity of from 100 to 50,000 MPa·s at 25° 0 C.
13. The thermally conductive silicone composition according to claim 12 , in which Component (A) comprises at least one of an alkyl group, an alkenyl group, and an aryl group.
14. The thermally conductive silicone composition according to claim 13 , in which the alkyl group comprises a methyl group, the alkenyl group comprises a vinyl group and the aryl group comprises a phenyl group.
15. The thermally conductive silicone composition according to claim 14 , in which Component (A) has an average of at least 0.8 silicon-bonded alkyenyl groups per molecule.
16. The thermally conductive silicone composition according to claim 1 , in which Component (A) has an average of at least 0.1 silicon-bonded alkyenyl groups per molecule.
17. The thermally conductive silicone composition according to claim 16 , in which Component (A) has an average of at least 0.8 silicon-bonded alkyenyl groups per molecule.
18. The thermally conductive silicone composition according to claim 1 , in which p is an integer of 110 to 190.