Thermal interface material and method for making same

Abstract

A thermal interface material includes a curable matrix, a plurality of thermally conductive fibers, and a plurality of the thermally conductive fillers. The thermally conductive fibers and the thermally conductive fillers are embedded in the matrix. The thermally conductive fibers and the thermally conductive fillers are embedded in the matrix. The thermally conductive fillers and the thermally conductive fibers interconnect with each other to cooperatively form a thermally conductive framework in the matrix. A method for making the thermal interface material is also provided.

1 . A thermal interface material comprising: 
 a matrix;    a plurality of thermally conductive fibers embedded in the matrix; and    a plurality of the thermally conductive fillers embedded in the matrix, the thermally conductive fillers and the thermally conductive fibers interconnecting with each other to cooperatively form a thermally conductive framework in the matrix.    
   
   
       2 . The thermal interface material as claimed in  claim 1 , wherein the thermally conductive fillers each interconnect with one or more adjacent thermally conductive fibers.  
   
   
       3 . The thermal interface material as claimed in  claim 1 , wherein the thermally conductive fillers are comprised of a thermally conductive material selected from the group consisting of silver, gold, copper, nickel, aluminum, alumina, aluminum nitride, boron nitride, zinc oxide, graphite, carbon black, and any combination thereof.  
   
   
       4 . The thermal interface material as claimed in  claim 1 , wherein the thermally conductive fillers have an average grain size of less than about 1 micrometer.  
   
   
       5 . The thermal interface material as claimed in  claim 1 , wherein the thermally conductive fibers are comprised of a thermally conductive material selected from the group consisting of carbon nanotubes, metal fibers, oxide fibers, boron nitride nanotubes, carbon fibers, and any combination thereof.  
   
   
       6 . The thermal interface material as claimed in  claim 1 , wherein the thermally conductive fibers have a diameter of less than about  1  micrometer.  
   
   
       7 . The thermal interface material as claimed in  claim 1 , wherein a ratio of the fibers to the fillers by weight is in the range from about 1:10 to about 1:1.  
   
   
       8 . The thermal interface material as claimed in  claim 1 , wherein a ratio of a total weight of the fibers plus fillers to a weight of the matrix is in the range from about 1:1 to about 20:1.  
   
   
       9 . The thermal interface material as claimed in  claim 1 , wherein the matrix is comprised of a macromolecular material selected from the group consisting of polyvinylacetate, polyvinyl, silicone grease, polyorganosiloxane, polyvinyl chloride, polyol, epoxies, polyester, polyacrylic acid, polypropylene, polyoxymethylene, polyacetal, polyvinyl alcohol, polyolefin, and any combination thereof.  
   
   
       10 . The thermal interface material as claimed in  claim 1 , wherein the thermal interface material has a thickness in the range from about 1 micrometer to about 100 micrometers.  
   
   
       11 . A method for making a thermal interface material, comprising the steps of: 
 loosely interconnecting a plurality of thermally conductive fillers and a plurality of thermally conductive fibers in a liquid curable material; and    curing the liquid curable material, whereby the fillers and the fibers interconnect with each other to cooperatively form a thermally conductive framework in a matrix of the cured material.    
   
   
       12 . The method according to  claim 11 , wherein the loosely interconnecting step comprises: mixing the fillers and the fibers to form a thermally conductive loose framework; and submerging the loose framework in the liquid curable material.  
   
   
       13 . The method according to  claim 11 , wherein the loosely interconnecting step is performed by directly mixing the fillers and the fibers in the liquid curable material to form a thermally conductive loose framework in the liquid curable material.  
   
   
       14 . The method according to  claim 11 , wherein the thermally conductive framework in the matrix defines a thermal interface material precursor, and the method further comprises the step of grinding the precursor using a three roller-mingling machine.  
   
   
       15 . The method according to  claim 11 , wherein the loosely interconnecting step is performed in a machine selected from the group consisting of a three roller-mingling machine, a planetary mingling machine, and a grinding machine.  
   
   
       16 . The method according to  claim 11 , wherein the thermally conductive fibers are comprised of a thermally conductive material selected from the group consisting of carbon nanotubes, metal fibers, oxide fibers, boron nitride nanotubes, carbon fibers, and any combination thereof.  
   
   
       17 . A thermal management system comprising: 
 a heat source;    a heat spreader; and    a thermal interface material between the heat source and the heat spreader, the thermal interface material comprising: 
 a matrix;  
 a plurality of thermally conductive fibers embedded in the matrix; and  
 a plurality of the thermally conductive fillers embedded in the matrix, the thermally conductive fillers and the thermally conductive fibers interconnecting with each other to cooperatively form a thermally conductive framework in the matrix.