Thermally conductive silicone composition

Abstract

A composition contains: (A) a curable silicone composition including: (a1) a vinyldimethylsiloxy-terminated polydimethylpolysiloxane having a viscosity in a range of 30-400 milliPascal*seconds, (a2) a silicon-hydride functional crosslinker, and (a3) a hydrosilylation catalyst, where the molar ratio of silicon-hydride functionality from the crosslinker to vinyl functionality is in a range of 0.5:1 to 1:1; (B) a filler treating agent comprising one or both of an alkyl trialkoxysilane and a mono-trialkoxysiloxy terminated dimethylpolysiloxane; and (C) a thermally conductive filler mixture including (c1) 40-55 wt % of aluminum nitride fillers, containing a blend of: (c1-a) 15-41 wt % of spherical aluminum nitride particles having a D50 particle size of 100 micrometers or more, and (c1-b) spherical or irregular shaped aluminum nitride particles having a D50 particle size of 20-80 micrometers; (c2) spherical aluminum oxide particles having a D50 particle size of 1-5 micrometers; and (c3) 10-20 wt % of irregular zinc oxide particles having a D50 particle size of 0.1-0.5 micrometer; where the total amount of the thermally conductive filler mixture is 94-97 wt %; and where wt % values are relative to the weight of the thermally conductive composition unless otherwise stated.