Heat-dissipating member and joined structure

Abstract

It is an object of the present invention to provide a heat-dissipating member, which has an excellent handling property at room temperature and can tightly adhere to a heat generating element and a heat sink by being interposed between the heat generating element and the heat sink and by having high flexibility to efficiently conduct heat generated from the heat generating element to the heat sink and can keep the state of adherence even in increasing in temperature, and a joined structure obtainable by joining a heat sink to a heat generating element with the heat-dissipating member. The present invention relates to a heat-dissipating member, which comprises a thermoplastic resin composition containing a thermoplastic resin and a thermally conductive fine particle and not containing a compound having a melting temperature in the range of 40 to 80° C., at 23° C., a storage modulus at 0.1 Hz is 50,000 Pa or larger and the member remains finite in shape, and in the range of 50 to 80° C., a storage modulus at 0.1 Hz being 400 to 50,000 Pa and the member being indefinite in shape, and at 100° C., a storage modulus at 0.1 Hz being 5,000 Pa or smaller and the member being indefinite in shape.

1 . A heat-dissipating member, 
 which comprises a thermoplastic resin composition containing a thermoplastic resin and a thermally conductive fine particle and not containing a compound having a melting temperature in the range of 40 to 80° C.,    at 23° C., a storage modulus at 0.1 Hz being 50,000 Pa or larger and the member remains finite in shape, and    in the range of 50 to 80° C., a storage modulus at 0.1 Hz being 400 to 50,000 Pa and the member being indefinite in shape, and    at 100° C., a storage modulus at 0.1 Hz being 5,000 Pa or smaller and the member being indefinite in shape.    
   
   
       2 . The heat-dissipating member according to  claim 1 , 
 wherein the thermoplastic resin is a styrene block copolymer and/or a butyl-rubber resin.    
   
   
       3 . The heat-dissipating member according to  claim 2 , 
 wherein the styrene block copolymer is a styrene-isoprene-styrene block copolymer having the proportion of diblock of styrene-isoprene being 50% by weight or larger and the content of styrene being 25% by weight or smaller.    
   
   
       4 . The heat-dissipating member according to  claim 1 , 
 wherein the thermoplastic resin composition mainly contains an aromatic thermoplastic resin being solid at 23° C. and further contains a xylene resin having viscosity at 23° C.    
   
   
       5 . A joined structure obtainable by joining a heat sink to a heat generating element with the heat-dissipating member according to  claim 1 , 
 wherein thickness of the heat-dissipating member may be reduced by heat generation of the heat generating element compared with thickness of the member before the heat generation.    
   
   
       6 . A joined structure obtainable by joining a heat sink to a heat generating element with the heat-dissipating member according to  claim 1 , 
 wherein thickness of the heat-dissipating member has already been reduced by heat generation of the heat generating element compared with thickness of the member before the heat generation.    
   
   
       7 . The heat-dissipating member according to  claim 2 , 
 wherein the thermoplastic resin composition mainly contains an aromatic thermoplastic resin being solid at 23° C. and further contains a xylene resin having viscosity at 23° C.    
   
   
       8 . The heat-dissipating member according to  claim 3 , 
 wherein the thermoplastic resin composition mainly contains an aromatic thermoplastic resin being solid at 23° C. and further contains a xylene resin having viscosity at 23° C.    
   
   
       9 . A joined structure obtainable by joining a heat sink to a heat generating element with the heat-dissipating member according to  claim 2 , 
 wherein thickness of the heat-dissipating member may be reduced by heat generation of the heat generating element compared with thickness of the member before the heat generation.    
   
   
       10 . A joined structure obtainable by joining a heat sink to a heat generating element with the heat-dissipating member according to  claim 3 , 
 wherein thickness of the heat-dissipating member may be reduced by heat generation of the heat generating element compared with thickness of the member before the heat generation.    
   
   
       11 . A joined structure obtainable by joining a heat sink to a heat generating element with the heat-dissipating member according to  claim 4 , 
 wherein thickness of the heat-dissipating member may be reduced by heat generation of the heat generating element compared with thickness of the member before the heat generation.    
   
   
       12 . A joined structure obtainable by joining a heat sink to a heat generating element with the heat-dissipating member according to  claim 2 , 
 wherein thickness of the heat-dissipating member has already been reduced by heat generation of the heat generating element compared with thickness of the member before the heat generation.    
   
   
       13 . A joined structure obtainable by joining a heat sink to a heat generating element with the heat-dissipating member according to  claim 3 , 
 wherein thickness of the heat-dissipating member has already been reduced by heat generation of the heat generating element compared with thickness of the member before the heat generation.    
   
   
       14 . A joined structure obtainable by joining a heat sink to a heat generating element with the heat-dissipating member according to  claim 4 , 
 wherein thickness of the heat-dissipating member has already been reduced by heat generation of the heat generating element compared with thickness of the member before the heat generation.