Tobacco smoke filter
A tobacco smoke filter which gives an acceptable vapor phase filtration and flavor delivery in the presence of a volatile flavorant (e.g. menthol), the filter containing activated carbon in which (1) pores of under 2 nm pore diameter (micropores) provide a pore volume of at most 0.3 cm 3 /g (NZ); and (2) (a) pores of 2 to 50 nm pore diameter (mesopores) provide a pore volume of at least 0.25 cm 3 /g (N 2 ) and/or (b) pores of 7 to 50 nm diameter (larger mesopores) provide a pore volume of at least 0.12 cm 3 /g (Hg).
1. A tobacco smoke filter containing activated carbon having micropores of under 2 nm pore diameter and first mesopores having a pore diameter of 2 to 50 nm and second mesopores having a pore diameter of 7 to 50 nm pore diameter, and a flavourant, the micropores having a micropore volume at most 0.3 cm 3 /g (N 2 ), the first mesopores having a mesopore volume of at least 0.25 cm 3 /g (N 2 ) and the second mesopores having a mesopore volume of at least 0.12 cm 3 /g (Hg); wherein the first mesopores and the second mesopores having different pore diameters and different mesopore volumes.
2. A tobacco smoke filter according to claim 1 wherein macropores of over 50 nm diameter provide a surface area of at least 5 m 2 /g (Hg).
3. A tobacco smoke filter according to claim 1 wherein said micropore volume is at most 0.26 cm 3 /g (N 2 ).
4. A tobacco smoke filter according to claim 1 wherein said micropore volume is at most 0.15 cm 3 /g (N 2 ).
5. A tobacco smoke filter according to claim 1 wherein said first mesopores having a mesopore volume of about 0.3 cm 3 /g (N 2 ).
6. A tobacco smoke filter according to claim 1 wherein said first mesopores having a mesopore volume over 0.4 cm 3 /g (N 2 ) or over 0.5 cm 3 /g (N 2 ).
7. A tobacco smoke filter according to claim 1 wherein said second mesopores having a mesopore volume of at least 0.13 cm 3 /g (Hg).
8. A tobacco smoke filter according to claim 1 wherein said second mesopores having a mesopore volume over 0.3 cm 3 /g (Hg).
9. A filter cigarette containing a tobacco smoke filter of claim 1 , wherein said flavourant comprises menthol.
10. A filter cigarette according to claim 9 , wherein said flavourant is applied to said activated carbon.
11. A tobacco smoke filter according to claim 1 wherein said second mesopores having a mesopore volume over 0.5 cm 3 /g (Hg).