Aerosol-forming substrate with expanded graphite

Abstract

An aerosol-forming substrate for use in a heated aerosol-generating article comprises expanded graphite particles. Expanded graphite particles have high thermal conductivity and low density and may improve efficiency of aerosol delivery from the substrate.

1 . An aerosol-forming substrate for use in a heated aerosol-generating article, the aerosol-forming substrate comprising expanded graphite particles. 
     
     
         2 . An aerosol-forming substrate according to  claim 1  in which the aerosol-forming substrate has a thermal conductivity of at least 0.12 W/(mK). 
     
     
         3 . An aerosol-generating article according to  claim 1  in which the expanded graphite particles make up at least 1 wt. % of the aerosol-forming substrate. 
     
     
         4 . An aerosol-forming substrate according to  claim 1  comprising, on a dry weight basis:
 between 1 and 90 wt. % expanded graphite particles; 
 between 7 and 60 wt. % of an aerosol former; 
 between 2 and 20 wt. % of fibres; and 
 between 2 and 10 wt. % of a binder. 
 
     
     
         5 . An aerosol-forming substrate according to  claim 1 , comprising between 1 and 15 wt. % expanded graphite particles. 
     
     
         6 . An aerosol-forming substrate according to  claim 1 , wherein the expanded graphite particles have a particle size distribution having a volume D10 particle size between 1 and 20 microns. 
     
     
         7 . An aerosol-forming substrate according to  claim 1 , wherein the expanded graphite particles have a particle size distribution having a volume D90 particle size between 50 and 300 microns. 
     
     
         8 . An aerosol-forming substrate according to  claim 1 , wherein the expanded graphite particles are substantially homogeneously distributed throughout the aerosol-forming substrate. 
     
     
         9 . An aerosol-forming substrate according to  claim 1 , wherein the aerosol-forming substrate is a tobacco-free aerosol-forming substrate. 
     
     
         10 . An aerosol-forming substrate according to  claim 1  comprising tobacco particles. 
     
     
         11 . A method of forming an aerosol-forming substrate according to  claim 1 , the method comprising:
 forming a slurry comprising expanded graphite particles, an aerosol former, fibres, and a binder;   casting and drying the slurry to form the aerosol-forming substrate or a precursor to the aerosol-forming substrate.   
     
     
         12 . A method according to  claim 11 , wherein forming the slurry comprises:
 forming a first mixture comprising:
 the aerosol former; 
 the fibres; 
 water; 
 optionally, an acid; and 
 optionally, nicotine, 
   forming a second mixture comprising:
 the expanded graphite particles; and 
 the binder, 
   and adding the second mixture to the first mixture to form a combined mixture.   
     
     
         13 . An aerosol-generating article comprising an aerosol-forming substrate according to  claim 1 . 
     
     
         14 . An aerosol-generating article according to  claim 13  comprising a plurality of elements, including the aerosol-forming substrate, assembled within a wrapper. 
     
     
         15 . An aerosol-generating system comprising an aerosol-generating article according to  claim 13  and an electrical aerosol-generating device for heating the aerosol-forming substrate.