| 摘要 |
PROBLEM TO BE SOLVED: To aim at the improvement of a heat conductivity by forming a silicone rubber composition containing a specific organopolysiloxane, a heat conductive boron nitride filler and a cross-linking agent as a sheet state and vulcanizing. SOLUTION: This insulating heat releasing sheet is obtained by blending 100 pts.wt. organopolysiloxane having >=25 cst viscosity at 25 deg.C, of the formula: RaSiO(4-a)/2 [R is a monovalent hydrocarbon group (a) is 1.85-2.10], with 30-500 pt.wt., especially 100-300 pt.wt. heat conductive boron nitride having 3-50% degree of aggregation, <=10 m<2> /g, especially <=5 m<2> /g specific surface area, >=500 Å, especially >=700 Å crystallite size, >=95 wt.%, especially >=98 wt.% purity and 1-30 μm, especially 5-20 μm average particle diameter of primary particles, and 0.1-10 pt.wt. cross-linking agent such as benzoyl peroxide and 2,4-dichlorobenzoyl peroxide to obtain a silicone rubber composition, forming the silicone rubber composition into a sheet state material and vulcanizing. |
