Low heat resistance silicone composition

A low heat resistance silicone composition, comprising:

• (A) 5 to 99 parts by weight of an organopolysiloxane having a kinematic viscosity at 25° C. of 10 to 10,000 mm2/s and represented by the following general formula (1):
• wherein R1 is each independently an unsubstituted or substituted monovalent hydrocarbon group having 1 to 18 carbon atoms, R2 is each independently alkyl, alkoxyalkyl, alkenyl, or acyl, a is an integer of 5 to 100, and b is an integer of 1 to 3;
• (B) 95 to 1 part by weight of an organopolysiloxane having a kinematic viscosity at 25° C. of 10 to 100,000 mm2/s and represented by the following general formula (2):
• R3SiO(4-c)/2 (2)
• wherein R3 is each independently an unsubstituted or substituted monovalent hydrocarbon group having 1 to 18 carbon atoms, and c is a number of 1.8 to 2.2,
• provided that the total amount of components (A) and (B) combined is 100 parts by weight;
• (C) an α-aluminum oxide powder, the α-aluminum oxide having a crystal structure of a hexagonal close-packed lattice which is formed of a polyhedron with 8 or more faces, and a particle shape with a D/H ratio of 0.3 to 30 when a maximum particle diameter parallel to a hexagonal lattice face of the hexagonal close-packed lattice is taken as D and a particle diameter perpendicular to the hexagonal lattice face is taken as H, and the α-aluminum oxide powder having an average particle diameter of 0.3 to 5 μm, a content ratio of coarse particles with 10 μm or more in a laser diffraction-type particle size distribution of 1% by weight or less of the entire component (C), and a purity of 99% or more;
• and
• (D) a spherical and/or irregular-shaped zinc oxide powder having an average particle diameter of 0.01 μm or more and less than 3 μm, and a content ratio of coarse particles with 10 μm or more in a laser diffraction-type particle size distribution of 1% by weight or less of the entire component (D),
• provided that a weight ratio of component (C) and component (D) is 5/5 to 9.5/0.5, and the total amount of components (C) and (D) combined is 65 to 80% by volume of the entire composition,
• the composition having a heat conductivity of 2 W/m·K or more and less than 4 W/m·K as measured by a hot disk method in accordance with ISO 22007-2, and a viscosity at 25° C. of 5 to 800 Pa·s as measured by a spiral viscometer at a rotation speed of 10 rpm.