Carbon fiber powder, a method of making the same, and thermally conductive composition

Abstract

A carbon fiber powder is produced by graphitizing a polymeric fiber having an aromatic ring on its main chain by heating and then pulverizing or cutting it. The polymeric fiber is selected from the group consisting of polybenzazole fiber, aromatic polyamide fiber, aromatic polyimide fiber, polyphenylene sulfide fiber, and wholly aromatic polyester fiber. The carbon fiber is preferably graphitized by heating the polymeric fiber at least 2500 degree C. under vacuum or in an inert gas. Thus, the carbon fiber powder that has excellent thermal conductivity and filling capability, a method of making the carbon fiber powder, and a thermally conductive composition including the carbon fiber powder are provided.

1 . A carbon fiber produced by graphitizing a polymeric fiber having an aromatic ring on its main chain by heating.  
     
     
         2 . The carbon fiber according to  claim 1 , wherein the polymeric fiber is selected from the group consisting of polybenzazole fiber, aromatic polyamide fiber, aromatic polyimide fiber, polyphenylene sulfide fiber, and wholly aromatic polyester fiber.  
     
     
         3 . The carbon fiber according to  claim 1 , wherein the carbon fiber has an interplanar spacing (d002) of graphite planes of less than 0.3370 nm by X-ray diffractometry.  
     
     
         4 . A method of making a carbon fiber comprising: 
 graphitizing a polymeric fiber having an aromatic ring on its main chain by heating the polymeric fiber at least 2500 degree C. under vacuum or in an inert gas.    
     
     
         5 . The method according to  claim 4 , wherein the polymeric fiber is selected from the group consisting of polybenzazole fiber, aromatic polyamide fiber, aromatic polyimide fiber, polyphenylene sulfide fiber, and wholly aromatic polyester fiber.  
     
     
         6 . A carbon fiber powder produced by graphitizing a polymeric fiber having an aromatic ring on its main chain by heating.  
     
     
         7 . The carbon fiber powder according to  claim 6 , wherein the polymeric fiber is selected from the group consisting of polybenzazole fiber, aromatic polyamide fiber, aromatic polyimide fiber, polyphenylene sulfide fiber, and wholly aromatic polyester fiber.  
     
     
         8 . The carbon fiber powder according to  claim 6 , wherein the carbon fiber powder has an interplanar spacing (d002) of graphite planes of less than 0.3370 nm by X-ray diffractometry.  
     
     
         9 . The carbon fiber powder according to  claim 6 , wherein the fiber powder has a diameter of from 5 to 20 μm and an average particle size of from 5 to 500 μm.  
     
     
         10 . A method of making a carbon fiber powder comprising: 
 graphitizing a polymeric fiber having an aromatic ring on its main chain by heating the polymeric fiber at least 2500 degree C. under vacuum or in an inert gas.    
     
     
         11 . The method according to  claim 10  further comprising: 
 pulverizing or cutting the polymeric fiber after the graphitizing step.  
 
     
     
         12 . The method according to  claim 10 , wherein the polymeric fiber is selected from the group consisting of polybenzazole fiber, aromatic polyamide fiber, aromatic polyimide fiber, polyphenylene sulfide fiber, and wholly aromatic polyester fiber.  
     
     
         13 . A thermally conductive composition comprising: 
 a matrix; and    carbon fiber powders mixed in the matrix, wherein the carbon fiber powder is produced by graphitizing a polymeric fiber having an aromatic ring on its main chain by heating.    
     
     
         14 . The composition according to  claim 13 , wherein the matrix has at least one polymeric material selected from the group consisting of vulcanized rubber, thermoplastic elastomer, thermoplastic resin, and thermosetting resin.  
     
     
         15 . The composition according to  claim 13 , wherein the content of the carbon fiber powders is from 1 to 800 parts by weight relative to 100 parts by weight of the matrix.  
     
     
         16 . The composition according to  claim 13 , wherein the composition is a thermally conductive molded article molded into a predetermined shape.  
     
     
         17 . The composition according to  claim 13 , wherein the composition is a thermally conductive sheet.  
     
     
         18 . The composition according to  claim 13 , wherein the composition is a thermally conductive adhesive.  
     
     
         19 . The composition according to  claim 13 , wherein the composition is a thermally conductive grease.