Heat-Transfer Sheet, Heat Transfer System, and Method of Using Heat-Transfer Sheet

Abstract

This invention provides (i) a heat-transfer sheet which comes into close contact with a heat generator and a radiator when caught there between and can be used repeatedly, (ii) a method of using the heat-transfer sheet, and (iii) a heat transfer system comprising the heat-transfer sheet. The heat-transfer sheet is made of expanded graphite and disposed between a heat generator and a radiator, and its bulk density is less than 1.0 Mg/m 3 . Because its bulk density is low, it is easily compressed between the heat generator and the radiator even under low pressure to be put into close contact with them. Thus, the thermal resistance between the heat generator and the heat sink is low and, hence, the heat generator is efficiently cooled down.

1 . A heat-transfer sheet which is made of expanded graphite and disposed between a heat generator and a radiator and whose bulk density is less than 1.0 Mg/m 3 . 
   
   
       2 . The heat-transfer sheet according to  claim 1  whose compressibility is 50% or more and whose recovery is 5% or more when it is thicknesswise compressed by the pressure of 34.3 MPa. 
   
   
       3 . A heat transfer system comprising a radiator and the heat-transfer sheet of  claim 1  disposed between the radiator and a heat generator. 
   
   
       4 . A method of using a heat-transfer sheet which is made of expanded graphite, whose bulk density is less than 1.0 Mg/m 3 , and which is disposed between a heat generator and a radiator to be thicknesswise compressed therebetween by the pressure of 2.0 MPa or less. 
   
   
       5 . A method of using a heat-transfer sheet which is made of expanded graphite, whose bulk density is less than 0.9 Mg/m 3 , and which is disposed between a heat generator and a radiator to be thicknesswise compressed therebetween by the pressure of 1.5 MPa or less. 
   
   
       6 . A heat transfer system comprising a radiator and the heat-transfer sheet of  claim 2  disposed between the radiator and a heat generator.