Manufacture of materials from graphite particles

Abstract

A method of manufacturing flexible sheets of expanded graphite material from recycled materials, comprising providing source materials in the form of flexible sheets of expanded graphite; comminuting the source materials into particles; re-expending the particles; and preparing a mat from the re-expanded particles. Also described herein is a process of manufacturing a graphite material comprising grinding a cured resin impregnated graphite material into particles; removing at least part of the resin from the particles; and expanding the resin removed particles.

1 . A method of manufacturing flexible sheets of expanded graphite material from recycled materials, comprising: 
 (a) providing source materials in the form of flexible sheets of expanded graphite;    (b) comminuting the source materials into particles;    (c) re-expanding the particles; and    (d) preparing a mat from the re-expanded particles.    
   
   
       2 . The method of  claim 1 , further comprising: 
 compressing the mat into a flexible sheet of expanded graphite material.    
   
   
       3 . The method of  claim 1 , wherein: 
 in step (a) the source materials are selected from the group consisting of unimpregnated expanded graphite sheets, uncured resin impregnated expanded graphite sheets and cured resin impregnated graphite sheets.    
   
   
       4 . The method of  claim 1 , wherein: 
 in step (a) the source materials include resin impregnated expanded graphite sheets.    
   
   
       5 . The method of  claim 4 , further comprising: 
 between steps (b) and (c), removing at least part of the resin from the particles.    
   
   
       6 . The method of  claim 5 , wherein: 
 the removing step includes heating the particles, while avoiding flashing of the resin decomposition products from the particles.    
   
   
       7 . The method of  claim 5 , wherein: 
 the removing step includes heating the particles at less than about 600° C.    
   
   
       8 . The method of  claim 5 , wherein: 
 the removing step includes heating the particles to a temperature in a range of from about 250° C. to about 600° C.    
   
   
       9 . The method of  claim 5 , wherein: 
 the removing step includes heating the particles at about 500° C. for about 150 minutes.    
   
   
       10 . The method of  claim 5 , further comprising: 
 compressing the mat into a flexible sheet of expanded graphite material; and    wherein the removing step results in increased tensile strength of the sheet created in the compressing step, as compared to a similar method in which the resin is not removed.    
   
   
       11 . The method of  claim 5 , wherein the removing step further comprises: 
 removing greater than 75% of the resin.    
   
   
       12 . The method of  claim 1 , wherein: 
 step (c) includes steps of intercalating the particles and heating the intercalated particles.    
   
   
       13 . The method of  claim 12 , wherein: 
 in step (c), the particles are expanded to have a specific volume of at least about 100 cc/g.    
   
   
       14 . The method of  claim 1 , wherein: 
 in step (b), the particles have a particle size of no greater than about 20 mesh.    
   
   
       15 . The method of  claim 1 , further comprising: 
 impregnating the mat with resin;    compressing the impregnated mat into a flexible sheet of expanded graphite material; and    embossing and curing the sheet.    
   
   
       16 . The method of  claim 1 , further comprising: 
 blending the particles with expandable natural graphite flakes.    
   
   
       17 . The method of  claim 16 , wherein: 
 step (c) includes steps of intercalating the particles and exfoliating the intercalated particles by heating the intercalated particles in a furnace; and    the blending step occurs in the furnace during the exfoliation process.    
   
   
       18 . A material suitable for the construction of a component of a fuel cell, manufactured by the process of  claim 1 .  
   
   
       19 . A process of manufacturing a graphite material comprising: 
 (a) grinding a resin impregnated graphite material into particles;    (b) removing at least part of the resin from the particles; and    (c) expanding the resin removed particles.    
   
   
       20 . The process of  claim 19 , further comprising: 
 after step (c), forming the expanded resin removed particles, into a flexible sheet of graphite material.    
   
   
       21 . The process of  claim 19 , wherein: 
 step (c) includes an intercalation process followed by exfoliation of the intercalated particles in a furnace.    
   
   
       22 . The process of  claim 21 , further comprising: 
 blending expandable natural graphite flake material with the intercalated particles in the furnace during the exfoliation process.    
   
   
       23 . The method of  claim 19 , wherein step (b), further comprises: 
 heating the particles, while avoiding flashing of theresin decomposition products from the particles.    
   
   
       24 . The method of  claim 19 , wherein: 
 the removing step includes heating the particles at less than about 600° C.    
   
   
       25 . The method of  claim 19 , wherein: 
 the removing step includes heating the particles to a temperature in a range of from about 300° C. to about 600° C.    
   
   
       26 . The method of  claim 19 , wherein: 
 the removing step includes heating the particles in the range of from about 400° C. to about 800° C. for a time in the range of from about 10 to about 150 minutes.    
   
   
       27 . The method of  claim 19 , wherein: 
 in step (a), the particles have a particle size of no greater than about 20 mesh.    
   
   
       28 . The method of  claim 19 , wherein: 
 in step (b), greater than 75% of the resin is removed.