| CPC C08L 83/06 (2013.01) [C08L 2205/025 (2013.01); C08L 2205/035 (2013.01)] | 8 Claims |
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1. A thermally-conductive two-part addition-curable silicone composition, comprising a first liquid and a second liquid,
the first liquid comprising:
a heat-treated mixture including
(A) an organopolysiloxane represented by the following average composition formula (1),
RaR1bSiO(4-a-b)/2 (1)
wherein R independently represents an alkenyl group, R1 independently represents an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, “a” represents 0.0001 to 0.2, “b” represents 1.7 to 2.2, and “a+b” represents a positive number satisfying 1.9 to 2.4, the organopolysiloxane having at least two alkenyl groups bonded to a silicon atom in one molecule, and
(C) aluminum oxide having Na+ ion content equal to or lower than 100 ppm, the Na+ ion content being determined by measuring an aqueous layer by ion chromatography, the aqueous layer being heat extract from aluminum oxide powders with pure water at 120° C. for 48 hours,
the component (C) having been subjected to surface treatment with a part of the component (A);
(E) a platinum-group metal catalyst; and
(F) an ion-trapping agent of a cation-exchange type and/or a cation-and-anion-exchange type, carrying at least one element selected from Zr, Bi, Sb, Mg, and Al,
the second liquid comprising:
a heat-treated mixture including
(A) an organopolysiloxane represented by the following average composition formula (1),
RaR1bSiO(4-a-b)/2 (1)
wherein R independently represents an alkenyl group, R1 independently represents an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, “a” represents 0.0001 to 0.2, “b” represents 1.7 to 2.2, and “a+b” represents a positive number satisfying 1.9 to 2.4, the organopolysiloxane having at least two alkenyl groups bonded to a silicon atom in one molecule,
(B) an organohydrogenpolysiloxane represented by the following average composition formula (2),
R2cHdSiO(4-c-d)/2 (2)
wherein R2 independently represents an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, “c” represents 0.7 to 2.2, “d” represents 0.001 to 0.5, and “c+d” represents a positive number satisfying 0.8 to 2.5, the organohydrogenpolysiloxane having at least three hydrogen atoms bonded to a silicon atom in one molecule, and
(C) aluminum oxide having Na+ ion content equal to or lower than 100 ppm, the Na+ ion content being determined by measuring an aqueous layer by ion chromatography, the aqueous layer being heat extract from aluminum oxide powders with pure water at 120° C. for 48 hours, the component (C) having been subjected to surface treatment with a part of the component (B); and
(D) an organohydrogenpolysiloxane represented by the following average composition formula (3),
R3eHfSiO(4-e-f)/n (3)
wherein R3 independently represents an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, “e” represents 0.7 to 2.2, “f” represents 0.001 to 0.5, and “e+f” represents a positive number satisfying 0.8 to 2.5, the organohydrogenpolysiloxane having at least two hydrogen atoms bonded to a silicon atom in one molecule,
wherein the first liquid does not contain the components (B) and (D), and the second liquid does not contain the components (E) and (F),
in the composition, the component (A) is contained in an amount of 100 parts by mass in total, the component (B) is contained in an amount such that a number of the hydrogen atom bonded to a silicon
atom (SiH group) in the component (B) is 0.1 to 2 per one alkenyl group in the component (A), the component (C) is contained in an amount of 1,000 to 7,000 parts by mass in total, the component (D) is contained in an amount such that a number of the hydrogen atom bonded to a silicon atom (SiH group) in the component (D) is 0.01 to 3 per one alkenyl group in the component (A), the component (E) is contained in an amount of 1 to 200 ppm in mass of a platinum group metal relative to the component (A), and the component (F) is contained in an amount of 0.01 to 10 parts by mass, and
the first liquid and the second liquid each have a thermal conductivity of 2.0 to 7.0 W/m·K in a hot disk method according to ISO 22007-2, and the first liquid and the second liquid each have a viscosity at 25° C. of 30 to 800 Pa·s when measurement is performed at a rotation number of 10 rpm at shear rate 6 (1/sec) in a rotor A using a spiral viscometer.
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