Aerosol-generating article having a thermal indicator

Abstract

An aerosol-generating article for an aerosol-generating device having a heating element is provided, the article including: a rod of aerosol-generating substrate formed of an aerosol-forming material having an aerosol former content of between 5 percent and 30 percent on a dry weight basis; and an outer wrapper wrapped around at least a portion of the rod, and at least a portion of an outer surface of the wrapper includes a thermal indicator including a thermochromic material, at least a portion of which is configured to undergo a visual change when a temperature at the portion exceeds a threshold temperature, such that the outer wrapper provides a visual indication that a temperature at the thermal indicator has exceeded the threshold temperature, the threshold temperature being at least about 175° C.

1 .- 15 . (canceled) 
     
     
         16 . An aerosol-generating article for an aerosol-generating device having a heating element, the aerosol-generating article comprising:
 a rod of aerosol-generating substrate, the rod of aerosol-generating substrate being formed of an aerosol-forming material having an aerosol former content of between 5 percent and 30 percent on a dry weight basis; and   an outer wrapper, wherein the outer wrapper is wrapped around at least a portion of the rod of aerosol-generating substrate and at least a portion of an outer surface of the wrapper comprises a thermal indicator, the thermal indicator comprising:
 a thermochromic material, whereby at least a portion of the thermochromic material is configured to undergo a visual change when a temperature at said portion of the thermochromic material exceeds a threshold temperature, such that the outer wrapper provides a visual indication that a temperature at the thermal indicator has exceeded the threshold temperature, wherein the threshold temperature is at least about 175 degrees Celsius. 
   
     
     
         17 . An aerosol-generating article for an aerosol-generating device having a heating element, the aerosol-generating article comprising:
 a rod of aerosol-generating substrate; and   an outer wrapper, wherein the outer wrapper is wrapped around at least a portion of the rod of aerosol-generating substrate and at least a portion of an outer surface of the wrapper comprises a thermal indicator, the thermal indicator comprising:
 a thermochromic material, whereby at least a portion of the thermochromic material is configured to undergo a visual change when a temperature at said portion of the thermochromic material exceeds a threshold temperature, such that the outer wrapper provides a visual indication that a temperature at the thermal indicator has exceeded the threshold temperature, wherein the threshold temperature is at least about 175 degrees Celsius, 
   wherein the thermal indicator overlies at least 5 square millimetres of an external surface area of the rod of aerosol-generating substrate.   
     
     
         18 . An aerosol-generating article for an aerosol-generating device having a heating element, the aerosol-generating article comprising:
 a rod of aerosol-generating substrate; and   an outer wrapper, wherein the outer wrapper is wrapped around at least a portion of the rod of aerosol-generating substrate and at least a portion of an outer surface of the wrapper comprises a thermal indicator, the thermal indicator comprising:
 a thermochromic material, whereby at least a portion of the thermochromic material is configured to undergo a visual change when a temperature at said portion of the thermochromic material exceeds a threshold temperature, such that the outer wrapper provides a visual indication that a temperature at the thermal indicator has exceeded the threshold temperature, wherein the threshold temperature is at least about 220 degrees Celsius. 
   
     
     
         19 . The aerosol-generating article according to  claim 16 , wherein the threshold temperature is at least about 220 degrees Celsius. 
     
     
         20 . The aerosol-generating article according to  claim 16 , wherein the thermal indicator overlies at least 5 square millimetres of an external surface area of the rod of aerosol-generating substrate. 
     
     
         21 . The aerosol-generating article according to  claim 16 , wherein the thermal indicator extends longitudinally along at least 50 percent of a total length of the rod of aerosol-generating substrate. 
     
     
         22 . The aerosol-generating article according to  claim 16 ,
 wherein the thermochromic material is arranged such that the visual change occurs only within a circumferential portion of the outer wrapper, and   wherein the circumferential portion extends only partially around a circumference of the aerosol-generating article.   
     
     
         23 . An aerosol-generating article for an aerosol-generating device having a heating element, the aerosol-generating article comprising:
 a rod of aerosol-generating substrate, the rod of aerosol-generating substrate being formed of an aerosol-forming material having an aerosol former content of between 5 percent and 30 percent on a dry weight basis; and   an outer wrapper, wherein at least a portion of an outer surface of the wrapper comprises a thermal indicator, wherein the thermal indicator is disposed downstream of the rod of aerosol-generating substrate, the thermal indicator comprising:
 a thermochromic material, whereby at least a portion of the thermochromic material is configured to undergo a visual change when a temperature at said portion of the thermochromic material exceeds a threshold temperature, such that the outer wrapper provides a visual indication that a temperature at the thermal indicator has exceeded the threshold temperature, wherein the threshold temperature is at least about 115 degrees Celsius. 
   
     
     
         24 . The aerosol-generating article according to  claim 16 , wherein the visual change is irreversible. 
     
     
         25 . The aerosol-generating article according to  claim 16 , wherein the thermal indicator extends longitudinally along at least 20 percent of a total length of the aerosol-generating article. 
     
     
         26 . The aerosol-generating article according to  claim 16 , wherein the visual change comprises a colour change. 
     
     
         27 . The aerosol-generating article according to  claim 16 , wherein the visual change comprises displaying a graphical representation and/or warning indicia or messages. 
     
     
         28 . The aerosol-generating article according to  claim 16 , wherein the outer wrapper comprises temperature indicating sensor paper, whereby the thermochromic material is integral to the temperature indicating sensor paper. 
     
     
         29 . The aerosol-generating article according to  claim 16 , wherein the thermochromic material comprises thermochromic paint, ink, or dye applied to the at least a portion of the outer surface of the wrapper. 
     
     
         30 . The aerosol-generating article according to  claim 16 , further comprising:
 a mouthpiece disposed downstream of the rod of aerosol-generating substrate;   a support element disposed immediately downstream of the rod of aerosol-generating substrate; and   an aerosol-cooling element disposed between the support element and the mouthpiece.   
     
     
         31 . A thermochromic material in a thermal indicator disposed on an outer wrapper of a rod of aerosol-generating substrate of an aerosol-generating article, the rod of aerosol-generating substrate being formed of an aerosol-forming material having an aerosol former content of between 5 percent and 30 percent on a dry weight basis and the aerosol-generating article being configured to be used with an aerosol-generating device having a heating element, wherein the outer wrapper is wrapped around at least a portion of the rod of aerosol-generating substrate and whereby at least a portion of the thermochromic material is configured to undergo a visual change when a temperature at said portion of the thermochromic material exceeds a threshold temperature, such that the outer wrapper provides a visual indication that a temperature at the thermal indicator has exceeded the threshold temperature, wherein the threshold temperature is at least about 175 degrees Celsius. 
     
     
         32 . A thermochromic material in a thermal indicator disposed on an outer wrapper of an aerosol-generating article, the aerosol-generating article being configured to be used with an aerosol-generating device having a heating element, and the aerosol-generating article comprising a rod of aerosol-generating substrate, the rod of aerosol-generating substrate being formed of an aerosol-forming material having an aerosol former content of between 5 percent and 30 percent on a dry weight basis, whereby the thermal indicator is disposed downstream of the rod of aerosol-generating substrate and at least a portion of the thermochromic material is configured to undergo a visual change when a temperature at said portion of the thermochromic material exceeds a threshold temperature, such that the outer wrapper provides a visual indication that a temperature at the thermal indicator has exceeded the threshold temperature, wherein the threshold temperature is at least about 115 degrees Celsius. 
     
     
         33 . An aerosol-generating system, comprising:
 an aerosol-generating article according to  claim 16 ; and   an aerosol-generating device configured to receive the aerosol-generating article, the aerosol-generating device comprising a heater element configured to heat a rod of aerosol-generating material,   wherein the heater element is configured so as to be controlled to operate below a maximum operating temperature,   wherein a thermal indicator of the aerosol-generating article is configured such that a threshold temperature is not exceeded during use of the aerosol-generating system with the heater element operating below the maximum operating temperature.