Heat radiating member

Abstract

A heat dissipating member which is disposed between a heat generating electronic component which when operated generates heat and reaches a temperature higher than room temperature and a heat dissipating component is characterized in that the heat dissipating member is non-fluid in a room temperature state prior to operation of the electronic component and acquires a low viscosity, softens or melts under heat generation during operation of the electronic component to fluidize at least a surface thereof so as to fill between the electronic component and the heat dissipating component without leaving any substantial voids, and the heat dissipating member is formed of a composition comprising a silicone resin and a heat conductive filler.

1 . A heat dissipating member which is disposed between a heat generating electronic component which when operated generates heat and reaches a temperature higher than room temperature and a heat dissipating component, characterized in that the heat dissipating member is non-fluid in a room temperature state prior to operation of the electronic component and acquires a low viscosity, softens or melts under heat generation during operation of the electronic component to fluidize at least a surface thereof so as to fill between the electronic component and the heat dissipating component without leaving any substantial voids, and the heat dissipating member is formed of a composition comprising a silicone resin and a heat conductive filler.  
     
     
         2 . The heat dissipating member of  claim 1 , comprising a silicone resin containing in the molecule RSiO 3/2  units (T units) and R 2 SiO 2/2  units (D units) wherein R is a substituted or unsubstituted monovalent hydrocarbon radical having 1 to 10 carbon atoms.  
     
     
         3 . The heat dissipating member of  claim 1 , comprising a silicone resin containing RSiO 3/2  units (T units) wherein R is a substituted or unsubstituted monovalent hydrocarbon radical having 1 to 10 carbon atoms and a silicone oil or gum having a viscosity of at least 100 Pa.s at 25° C.  
     
     
         4 . The heat dissipating member of  claim 1 ,  2  or  3  wherein the heat conductive filler has been surface treated.  
     
     
         5 . The heat dissipating member of  claim 4  wherein the heat conductive filler has been surface treated with an alkoxy group-containing diorganopolysiloxane or alkoxy group-containing silane.  
     
     
         6 . The heat dissipating member of any one of  claims 1  to  5  wherein the heat conductive filler is a mixture of a filler having an average particle size of 0.1 to 5 μm and a filler having an average particle size of 5 to 25 μm.  
     
     
         7 . The heat dissipating member of any one of  claims 1  to  6 , characterized by having a thermal conductivity of at least 0.5 W/mK and a viscosity of 1×10 2  to 1×10 5  Pa.s at 80° C.  
     
     
         8 . The heat dissipating member of any one of  claims 1  to  7 , characterized in that the composition is formed into a sheet or film.