Thermally conductive composition and methods and devices in which said composition is used

1. A composition comprising:

(A) An organopolysiloxane composition that comprises;

an organopolysiloxane having a general formula (I)

R 1 3 Si—(R 1 R 2 SiO) a (R 1 2 SiO) b —R 3 —SiR 1 3   (I)

wherein each R 1 is independently a C1-C6 alkyl group, each R 2 is an aryl group, each R 3 is selected from an oxygen atom or a divalent hydrocarbon group, subscript a is 0 or has an average value of at least 1, subscript b has an average value of at least 1;

(B) a filler treating agent;

(C) a thermal stabilizer; and

(D) thermally conductive filler, comprising:

(D-1) a small-particulate thermally conductive filler having a mean size of up to 3 μm;

(D-2) spherical aluminum nitride having a mean size of from 50 to 150 μm;

(D-3) boron nitride having a mean size of from 20 to 200 μm.

2. The composition according to claim 1 , wherein component (A) is curable.

3. The composition according to claim 2 , wherein component (A) is a combination of organopolysiloxanes comprising:

(A′1) An alkenyl-containing organopolysiloxane having general formulae

R 1 (3-p) R 4 p SiO(R 1 2 SiO) c (R 1 R 2 SiO) d (R 1 R 4 SiO) e SiR 1 (3-q) R 4 q ,   (II)

R 1 3 SiO(R 1 2 SiO) f (R 1 R 2 SiO) g (R 1 R 4 SiO) h SiR 1 3 ,   (III)

or

a combination thereof,

where each R 1 is independently an alkyl group, R 2 is independently an aryl group, R 4 is independently an alkenyl group, subscript d and subscript e may be 0 or a positive number, subscripts p and q are independently 0, 1, or 2, provided that p, q, and e are not all 0 at the same time,; and

(A′-2) organohydrogenpolysiloxane comprising a compound of the formulae

R 3 SiO(R 2 SiO) i (RHSiO) j SiR 3   (IV),

R 2 HSiO(R 2 SiO) k (RHSiO) l SiR 2 H   (V),

or a combination thereof,

where each R is independently independently a monovalent organic group, subscript i has an average value ranging from 0 to 2000, subscript j has an average value ranging from 2 to 2000, subscript k has an average value ranging from 0 to 2000, and subscript 1 has an average value ranging from 0 to 2000 , wherein the mole ratio of the alkenyl group in component (A′1) and the silicon-bonded hydrogen atom in component (A′2) is in the range of 10:1 to 1:10.

4. The composition according to claim 1 , wherein component (A) is cured.

5. The composition according to claim 1 , wherein component (B) comprises a silicone and/or a silane.

6. The composition according to claim 5 , wherein component (B) is selected from the group consisting of alkyl trialkoxysilane and alkenyl end-capped trialkoxysiloxy-terminated dimethylpolysiloxane.

7. The composition according to claim 6 , wherein component (B) is selected from n-decyltrimethoxysilane and dimethylvinylsiloxy- and trimethoxysiloxy-terminated dimethylpolysiloxane.

8. The composition according to claim 1 , wherein component (C) is phthalocyanine or metal phthalocyanine.

9. The composition of claim 1 , further comprising an additional ingredient selected from (G) a spacer, (H) an antioxidant stabilizer, (I) a pigment, (J) a vehicle, or (K) a wetting agent, and a combination thereof.

10. The composition of claim 2 in which component (A) is a curable composition, further comprising (E) curing catalyst and/or (F) curing inhibitor.

11. A method comprising interposing the composition of claim 1 along a thermal path between a heat source and a heat dissipator.

12. The method of claim 11 , where the heat source comprises an (opto)electronic component.

13. A device comprising:

a) a heat source,

b) a composition according to claim 1 , and

c) a heat dissipator;

where the composition is positioned between the heat source and the heat dissipator along a thermal path extending from a surface of the heat source to a surface of the heat dissipator.