Smoking article having a filter including a capsule

Abstract

There is provided a smoking article having an aerosol generating substrate and a mouthpiece. The mouthpiece includes a cavity at least partially filled with a particulate material, such as activated carbon,and contains at least one breakable capsule of a liquid flavourant at least partially surrounded by the particulate material, such that the force required to break the capsule within the mouthpiece to release the liquid flavourant is less than three times the inherent burst strength of the capsule.

Claims

1. A smoking article comprising: an aerosol generating substrate; and a mouthpiece comprising a cavity at least partially filled with a particulate material and containing a breakable capsule of a liquid flavourant at least partially surrounded by the particulate material, wherein the particulate material comprises at least one sorbent material and wherein the force required to break the capsule within the mouthpiece to release the liquid flavourant is less than three times the inherent burst strength of the capsule, wherein the hardness of the particulate material is at least 90% when measured in a Ball Pan Hardness test conducted in accordance with ASTM D3802 and wherein the at least one sorbent material has a total pore volume, and at least 30 percent of the total pore volume of the sorbent material is provided by pore sizes in the range of about 2 nm to about 50 nm, wherein the particulate material has a mean average particle size that is at least three times smaller than a maximum diameter of the breakable capsule, and wherein the particulate material occupies at least 60% of the space in the cavity that is not occupied by the capsule.

2. A smoking article according to claim 1, wherein the breakable capsule has an inherent burst strength of at least 10 Newtons.

3. A smoking article according to claim 1, wherein the breakable capsule has an inherent burst strength of at least 25 Newtons.

4. A smoking article according to claim 1, wherein the force required to break the capsule within the mouthpiece to release the liquid flavourant is less than 50 Newtons.

5. A smoking article according to claim 1, wherein the particulate material has a mesh size such that at least 95% of the particles fall between 12 and 20 mesh.

6. A smoking article according to claim 5, wherein the capsule has a diameter of between 3 millimeters and 5 millimeters.

7. A smoking article according to claim 1, wherein the BET surface area of the at least one sorbent material is less than 1500 square metres per gram.

8. A smoking article according to claim 1, wherein the particulate material has a bulk density of at least 0.3 grams per cubic centimeter.

9. A smoking article according to claim 1, wherein the length of the cavity, in the longitudinal direction of the mouthpiece, is at least about 1.5 mm greater than the maximum diameter of the breakable capsule.

10. A smoking article according to claim 1, wherein the breakable capsule comprises an outer shell encapsulating the liquid flavourant, wherein the outer shell has a thickness of at least 30 microns.

11. A smoking article according to claim 1, wherein the mouthpiece comprises a mouth end filter segment and a rod end filter segment, wherein the cavity is defined between the mouth end filter segment and the rod end filter segment.

12. A filter for a smoking article, the filter comprising a cavity at least partially filled with a particulate material and containing a breakable capsule of a liquid flavourant at least partially surrounded by the particulate material, wherein the particulate material comprises at least one sorbent material and wherein the force required to break the capsule within the filter to release the liquid flavourant is less than three times the inherent burst strength of the capsule, wherein the hardness of the particulate material is at least 90% when measured in a Ball Pan Hardness test conducted in accordance with ASTM D3802 and wherein the at least one sorbent material has a total pore volume, and at least 30 percent of the total pore volume of the sorbent material is provided by pore sizes in the range of about 2 nm to about 50 nm, wherein the particulate material has a mean average particle size that is at least three times smaller than a maximum diameter of the breakable capsule, and wherein the particulate material occupies at least 60% of the space in the cavity that is not occupied by the capsule.

13. A smoking article comprising: an aerosol generating substrate; and a mouthpiece comprising a cavity at least partially filled with a particulate material and containing a breakable capsule of a liquid flavourant at least partially surrounded by the particulate material, wherein the particulate material comprises at least one sorbent material and wherein the force required to break the capsule within the mouthpiece to release the liquid flavourant is less than three times the inherent burst strength of the capsule, wherein the particulate material has a mesh size such that at least 95% of the particles fall between 12 and 20 mesh, wherein the particulate material has a mean average particle size that is at least three times smaller than a maximum diameter of the breakable capsule, wherein the hardness of the particulate material is at least 90% when measured in a Ball Pan Hardness test conducted in accordance with ASTM D3802, wherein the at least one sorbent material has a total pore volume, and at least 30 percent of the total pore volume of the sorbent material is provided by pore sizes in the range of about 2 nm to about 50 nm, wherein the particulate material occupies at least 60% of the space in the cavity that is not occupied by the capsule and wherein the breakable capsule comprises an outer shell encapsulating the liquid flavourant, wherein the outer shell has a thickness of at least 30 microns.

14. A smoking article according to claim 13, wherein the capsule has a diameter of between 3 millimeters and 5 millimeters.

Description

(1) The invention will be further described, by way of example only, with reference to the accompanying drawings in which:

(2) FIG. 1 shows a longitudinal cross section of a smoking article according to the described embodiment.

(3) FIG. 1 is a perspective view of a smoking article 100 according to an embodiment of the invention. The smoking article 100 includes an aerosol forming substrate in the form of a generally cylindrical tobacco rod 101 and a mouthpiece in the form of a generally cylindrical filter 103. The tobacco rod 101 and filter 103 are axially aligned in an end-to-end relationship, preferably abutting one another. The tobacco rod 101 includes an outer wrapper 105 circumscribing the smoking material. The tobacco is preferably a shredded tobacco or tobacco cut filler. The filter 103 includes a filter wrapper (not shown) circumscribing the filter material. The tobacco rod 101 has an upstream, lit end 109 and a downstream end 111. The filter 103 has an upstream end 113 and a downstream, mouth end 115. The upstream end 113 of the filter 103 is adjacent the downstream end 111 of the tobacco rod 101. A breakable capsule 120 containing a liquid flavourant is disposed in a cavity of the filter 103. The cavity also contains a particulate material 125, in the form of activated carbon granules, which surround the breakable capsule 120. The capsule has a diameter of 3.5 mm and the cavity has a length of 5 mm along the longitudinal axis of the filter.

(4) The filter 103 is attached to the tobacco rod 101 by tipping material 117 which circumscribes the entire length of the filter 103 and an adjacent region of the tobacco rod 101. The tipping material 117 is shown partially removed from the smoking article in FIG. 1, for clarity. In this embodiment, the tipping material 117 also includes a circumferential row of perforations 123. The perforations 123 are provided for ventilation of the mainstream smoke.

EXAMPLES

(5) Two capsule containing filters were prepared and tested. The first filter (Sample A) was a standard capsule containing filter, in which a 3.5 mm diameter capsule was embedded within a single segment of cellulose acetate tow. The second filter (Sample B) was a filter in accordance with the present invention. That is, the second filter had a plug-space-plug construction with an 11 mm long upstream segment of cellulose acetate tow and an 11 mm long downstream segment of cellulose acetate tow defining a 5 mm wide cavity between them. The cavity contained a 3.5 mm diameter capsule surrounded by 70 mg of activated carbon particles. The activated carbon particles had a mesh size of 12 to 20 mesh. The filters of both samples were circumscribed with an 80 microns thick filter wrapper and a 40 micron thick tipping paper. The tipping paper was coated on its inner surface with a layer of nitrocellulose to prevent the liquid from the capsule from migrating to the outer surface of the filter. In both samples, the 3.5 mm diameter capsules had a burst strength of approximately 15 Newtons.

(6) An Alluris type FMI—220 C2—digital force gauge 0-200N device (commercially available from Alluris Gmbh & Co. KG, Germany) was used to apply a gradually increasing force to the capsule containing region of both filters, and record the force at which the capsule would break. In sample A, the capsule was found to break in the filter after a force of 45 Newtons had been applied to the filter. In sample B, the capsule was found to break in the filter after a force of 22 Newtons had been applied to the filter.