Smoking article filter with amorphous magnesium carbonate

Abstract

A filter for a smoking article includes filtration material and an amorphous magnesium carbonate material contained within the filtration material. A smoking article includes a smokable material and the filter downstream of the smokable material.

1 . A filter for a smoking article comprising, filtration material and an amorphous magnesium carbonate material contained within the filtration material. 
     
     
         2 . The filter according to  claim 1 , wherein the amorphous magnesium carbonate material is hygroscopic, wherein the amorphous magnesium carbonate material physically adsorbs at least about 1.5 mmol water/g at a relative humidity of about 10% at about 27 degree Celsius and one Atm. 
     
     
         3 . The filter according to  claim 1 , wherein the amorphous magnesium carbonate material has a BET surface area of at least about 300 m2/g. 
     
     
         4 . The filter according to  claim 1 , wherein the amorphous magnesium carbonate material has an average particle size in a range from 100 micrometres (about 140 mesh) to about 2000 micrometres (about 10 mesh). 
     
     
         5 . The filter according to  claim 1 , wherein the filter comprises about 10 mg to about 200 mg of amorphous magnesium carbonate material. 
     
     
         6 . The filter according to  claim 1 , wherein the filter comprises a mixture of crystalline magnesium carbonate material and amorphous magnesium carbonate contained within the filtration material. 
     
     
         7 . The filter according to  claim 1 , wherein the filter comprises a mixture of magnesium oxide material and amorphous magnesium carbonate contained within the filtration material. 
     
     
         8 . The filter according to  claim 1 , wherein the filtration material comprises a plug of tow material and the amorphous magnesium carbonate material is dispersed within the plug of tow material, and the tow material preferably comprises cellulose acetate. 
     
     
         9 . The filter according to  claim 1 , wherein the filter is a segmented filter comprising two filtration elements in axial alignment and separated by a void space, the void space containing the amorphous magnesium carbonate material. 
     
     
         10 . The filter according to  claim 1 , wherein the filter is a segmented filter comprising an upstream filtration element in axial alignment with a downstream filtration element, the upstream filtration element containing the amorphous magnesium carbonate material, and the downstream filtration element is free of the x-ray amorphous magnesium carbonate material. 
     
     
         11 . The filter according to  claim 1 , wherein the amorphous magnesium carbonate material comprises bound water. 
     
     
         12 . The filter according to  claim 1 , wherein the filter is free of activated carbon. 
     
     
         13 . The filter according to  claim 1 , further comprising activated carbon contained within the filtration material. 
     
     
         14 . A smoking article comprising:
 smokable material;   a filter, according to  claim 1 , downstream of the smokable material.   
     
     
         15 . The smoking article according to  claim 14 , wherein the smokable material comprises tobacco, or cut tobacco. 
     
     
         16 . The filter according to  claim 1 , wherein the amorphous magnesium carbonate material has a BET surface area within a range from about 300 m2/g to about 1200 m2/g. 
     
     
         17 . The filter according to  claim 16 , wherein the amorphous magnesium carbonate material has an average particle size in a range from about 200 micrometres (about 70 mesh) to about 1500 micrometres (about 14 mesh). 
     
     
         18 . The filter according to  claim 17 , wherein the amorphous magnesium carbonate material is hygroscopic, wherein the amorphous magnesium carbonate material physically adsorbs at least 2 mmol water/gram, at a relative humidity of about 10% at about 27 degree Celsius and one Atm. 
     
     
         19 . The filter according to  claim 18 , wherein the filter comprises a mixture of crystalline magnesium carbonate material and amorphous magnesium carbonate contained within the filtration material. 
     
     
         20 . A smoking article comprising:
 smokable material;   a filter, according to  claim 19 , downstream of the smokable material.