Improved aerosol-forming substrate

Abstract

There is provided an aerosol-forming substrate comprising, on a dry weight basis: between 10 and 90 wt % thermally conductive particles, each thermally conductive particle of the thermally conductive particles having a thermal conductivity of at least 1 W/(mK) in at least one direction at 25 degrees Celsius; 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. The aerosol-forming substrate has a thermal conductivity of at least 0.22 W/(mK) in at least one direction at 25 degrees Celsius. There is also provided an aerosol-generating article comprising the aerosol-forming substrate and a method of forming the aerosol-forming substrate.

1 . An aerosol-forming substrate comprising, on a dry weight basis:
 between 10 and 90 wt % thermally conductive particles, each thermally conductive particle of the thermally conductive particles having a thermal conductivity of at least 1 W/(mK) in at least one direction at 25 degrees Celsius;   between 7 and 60 wt % of an aerosol former;   between 2 and 20 wt % of fibres;   between 2 and 10 wt % of a binder; and   less than 5 wt % tobacco,   wherein the aerosol-forming substrate has a thermal conductivity of at least 0.22 W/(mK) in at least one direction at 25 degrees Celsius.   
     
     
         2 . An aerosol-forming substrate according to  claim 1 , wherein the thermally conductive particles have a particle size distribution having a volume D10 particle size between 1 and 20 microns 
     
     
         3 . An aerosol-forming substrate according to  claim 1 , wherein the thermally conductive particles have a particle size distribution having a volume D90 particle size between 50 and 300 microns. 
     
     
         4 . An aerosol-forming substrate according to  claim 1 , wherein the thermally conductive particles have a particle size distribution having a volume D10 particle size and a number D90 particle size, wherein the volume D90 particle size is no more than 50 times the number D10 particle size. 
     
     
         5 . An aerosol-forming substrate according to  claim 1 , wherein some or all of the thermally conductive particles are substantially spherical. 
     
     
         6 . An aerosol-forming substrate according to  claim 1 , wherein some or all of the thermally conductive particles comprise or consist of a susceptor material. 
     
     
         7 . An aerosol-forming substrate according to  claim 1 , wherein the substrate comprises, on a dry weight basis, at least 40 wt % of the thermally conductive particles. 
     
     
         8 . An aerosol-forming substrate according to  claim 1 , wherein the substrate comprises, on a dry weight basis, between 65 and 85 wt % of the thermally conductive particles. 
     
     
         9 . An aerosol-forming substrate according to  claim 1 , wherein the thermally conductive particles are substantially homogeneously distributed throughout the aerosol-forming substrate. 
     
     
         10 . An aerosol-forming substrate according to  claim 1 , wherein the aerosol-forming substrate is a tobacco-free aerosol-forming substrate. 
     
     
         11 . An aerosol-forming substrate according to  claim 1 , wherein the aerosol-forming substrate comprises between 1 and 20 wt % water. 
     
     
         12 . A combined aerosol-forming substrate comprising:
 a first material and a second material, the first material being comprised in the combined aerosol-forming substrate as a first plurality of discrete elements and the second material being comprised in the combined aerosol-forming substrate as a second plurality of discrete elements,   in which the first material comprises an aerosol former and has a first thermal conductivity,   and in which the second material comprises, or is, an aerosol-forming substrate according to  claim 1  and has a second thermal conductivity that is greater than the first thermal conductivity.   
     
     
         13 . An aerosol-generating article comprising an aerosol-forming substrate according to  claim 1 . 
     
     
         14 . 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 or combined aerosol-forming substrate of the aerosol-generating article. 
     
     
         15 . A method of forming an aerosol-forming substrate according to  claim 1 , the method comprising:
 forming a slurry comprising the thermally conductive particles, the aerosol former, the fibres, and the binder; and   casting and drying the slurry to form the aerosol-forming substrate or a precursor for forming into the aerosol-forming substrate.