Smoking article with mouth end cavity

Abstract

A smoking article (10) comprises a tobacco rod (12) and a filter (14) connected to the tobacco rod (12). The filter (14) comprises a first filter segment (18, 20) comprising one or more breakable capsules, wherein each breakable capsule comprises an outer shell and an inner core containing an additive. The filter (14) further comprises a hollow tube segment (22) downstream of the first filter segment (18, 20) and positioned between a downstream end of the first filter segment (18, 20) and the mouth end of the filter (14). The hollow tube segment (22) defines a cavity (24) at the mouth end of the filter (14). A plug wrap (23) circumscribes the first filter segment (18, 20) and the hollow tube segment (22), wherein the plug wrap (23) has a basis weight of less than 90 grams per square meter.

Claims

1. A smoking article comprising: a tobacco rod; a filter comprising: a first filter segment comprising one or more breakable capsules, each breakable capsule comprising an outer shell and an inner core containing an additive; a hollow tube segment downstream of the first filter segment, the hollow tube segment comprising a wall with an inner wall surface defining a cavity at the mouth end of the filter, the hollow tube segment positioned between a downstream end of the first filter segment and the mouth end of the filter; and a plug wrap circumscribing the first filter segment and an outer wall surface of the hollow tube segment, wherein the plug wrap has a basis weight of less than 90 grams per square meter, wherein the wall of the hollow tube segment is formed from a plurality of overlapping paper layers, adjacent paper layers of the wall of the hollow tube segment being adhered together by an intermediate layer of an adhesive; and a tipping wrapper circumscribing the plug wrap and at least a portion of the tobacco rod to connect the filter to the tobacco rod.

2. The smoking article according to claim 1, wherein the ovality of the hollow tube segment after a 50% deformation of the filter is less than 25%.

3. A smoking article according to claim 2 wherein the ovality of the tube segment is less than 25% after a capsule crush test in which a force corresponding to the crush strength of the one or more capsules is applied to the first filter segment.

4. A smoking article according to claim 1 wherein the ovality of the tube segment is less than 25% after a capsule crush test in which a force corresponding to the crush strength of the one or more capsules is applied to the first filter segment.

5. A smoking article according to claim 1, wherein the wall of the hollow tube segment is formed from a plurality of spirally wound paper layers.

6. A smoking article according to claim 1, wherein the difference between the ovality of the tube segment after 50% deformation of the filter and the ovality of the tube segment prior to deformation of the filter is less than 25%.

7. A smoking article according to claim 1, wherein the ovality of the hollow tube segment after a 50% deformation of the filter performed after the smoking article has been subjected to a smoking test is less than 35%.

8. A smoking article according to claim 1 wherein the hollow tube segment comprises a coating layer on an inner surface thereof.

9. A smoking article according to claim 1 wherein the compressive strength of the filter is at least 20 Newtons at 50% compression.

10. A smoking article according to claim 1 wherein the wall of the hollow tube segment has a thickness of between 150 micrometers and 500 micrometers.

11. A smoking article according to claim 1 wherein the hollow tube segment extends at least 2 mm from the downstream end of the first filter segment.

12. A smoking article according to claim 1 further comprising a rod end segment between the first filter segment and the tobacco rod.

13. A smoking article according to claim 1, wherein the tipping wrapper comprises paper having a basis weight between about 20 gsm and 70 gsm.

Description

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

(2) FIG. 1 shows a smoking article in accordance with the present invention;

(3) FIG. 2 shows the mouth end of the smoking article of FIG. 1 with the filter unwrapped;

(4) FIG. 3 shows an exemplary method of forming a tubular member for forming hollow tube segments in accordance with the present invention;

(5) FIG. 4 shows a method of forming a plurality of smoking article filter rods for use in producing smoking articles according to the present invention;

(6) FIG. 5 shows a dual filter rod;

(7) FIG. 6 shows a quad filter rod; and

(8) FIG. 7 shows an exemplary method for forming a smoking article using a dual filter rod.

(9) FIGS. 1 and 2 show a filter cigarette 10 in accordance with the present invention. The cigarette 10 comprises a wrapped rod 12 of tobacco cut filler which is attached at one end to an axially aligned filter 14. A tipping wrapper 16 circumscribes the filter 14 and a portion of the wrapped rod 12 of tobacco to join together the two portions of the cigarette 10.

(10) As shown in FIG. 2, the filter 14 comprises a rod end filter segment 18, a flavour containing filter segment 20, and a mouth end hollow tube segment 22. The segments 18, 20 and 22 are circumscribed by a combining plug wrap 23 which connects the three segments to form the filter 14. The combining plug wrap 23 has a basis weight of less than 90 gsm. One or more of the segments 18, 20, 22 may also be wrapped in an individual plug wrap.

(11) The rod end filter segment 18 and the flavour containing filter segment 20 are formed of a suitable filtration material, such as cellulose acetate tow. Furthermore, the flavour containing filter segment 20 comprises a suitable flavourant provided in the form of one or more breakable capsules contained within the flavour containing filter segment 20. The one or more breakable capsules may be ruptured by the consumer when desired by squeezing the flavour containing filter segment 20 between the consumer's fingers.

(12) The mouth end hollow tube segment 22 defines a mouth end cavity 24 in the filter 14 which extends between the downstream end of the flavour containing filter segment 20 and the mouth end edge of the filter 14. The mouth end hollow tube segment 22 may be formed of a plurality of spirally wound paper layers which can further improve the resistance to deformation of the mouth end cavity 24, for example during the rupture of the one or more breakable capsules when present in the flavour containing filter segment 20. The ovality of the tube segment after a 50% deformation of the filter 14 is less than 25%.

(13) FIG. 3 shows an exemplary method of forming a tube member 30 which can be cut to form a plurality of hollow tube segments for use in forming smoking articles in accordance with the present invention. A plurality of continuous paper plies 32 are spirally wound around a cylindrical mandrel 34 in a staggered, overlapping arrangement. A suitable adhesive may be applied to one or more of the plies 32 using an adhesive bath 36 prior to winding each ply around the mandrel 34. The plies 32 are driven by a rubber belt 38 so that the formed tubular member 30 rotates around the mandrel 34 until it is cut into desired lengths further downstream.

(14) To form a plurality of smoking articles in accordance with the present invention, the process illustrated in FIGS. 4 to 7 can be used. First, a plurality of filter rods is produced according to the process shown in FIG. 4. A substantially continuous array of filter components is formed by providing a plurality of tubular members 40, a plurality of flavour containing filter segments 20 and a plurality of rod end filter members 42. A tubular member 40 is provided between each pair of consecutive rod end filter members 42, and a flavour containing filter segment 20 is provided between each rod end filter member 42 and each tubular member 40. The substantially continuous array of filter components is then wrapped in a continuous sheet of plug wrap 44 to form a wrapped filter array.

(15) To form a plurality of filter rods, a plurality of first cuts 46 are made through at least some of the rod end filter members 42 of the wrapped filter array, each first cut 46 positioned at an intermediate position along the length of the respective rod end filter member 42. The resilience of each tubular member 40 advantageously prevents collapse of the cavities defined therein during the cutting process and subsequent handling of the filter rods and smoking articles incorporating filters manufactured from the filter rods.

(16) To form a dual filter rod, as shown in FIG. 5, the wrapped filter array is cut through each rod end filter member 42 so as to provide a filter rod having a rod end filter segment 18 at each end, two flavor containing filter segments 20 positioned between the two rod end filter segments 18, and a tubular member 40 positioned between the two flavor containing filter segments 20. The dual filter rod essentially defines two smoking article filters 14 which are joined by a continuous plug wrap 44 and a tubular member 40.

(17) Alternatively, a quad filter rod, as shown in FIG. 6, can be formed by cutting the wrapped filter array through every other filter member 42 so as to provide a filter rod which essentially comprises two joined dual filter rods.

(18) The formed filter rods can be used to form two or more smoking articles. For example, as shown in FIG. 7, a dual filter rod can be used to form two filter cigarettes 10 by placing a tobacco rod 12 in axial alignment with each end of the filter rod. A tipping wrapper 50 is then wrapped around the filter rod and a portion of each tobacco rod 12 adjacent the filter rod. The tipping wrapper 50, the plug wrap 44 and the tubular member 40 are then cut along a cut line 52 to form two filter cigarettes. The resilience of the tubular member 40 prevents collapse or deformation of the mouth end cavities of each cigarette 10 during the cutting process.

(19) To form a plurality of smoking articles using a quad filter rod, the filter rod is first cut through the rod end filter member 42 to form two dual filter rods. The two dual filter rods can then be used to form four smoking articles using the method shown in FIG. 7.