Smoking article including flavour granules having permeable outer layer

Abstract

A method for the production of a flavor granule for a smoking article comprises the steps of: a) forming an inner core by compaction of particles of herbaceous plant material; b) providing a coating suspension of colored binder particles comprising at least one colorant and at least one polymeric binder in a solvent; c) applying the coating suspension to the outer surface of the inner core to form an outer layer, wherein the coating suspension is applied to the inner core within a coating system and wherein within that coating system the vapor pressure of the solvent is greater than 5 kPa; and d) drying the outer layer to evaporate the solvent.

Claims

1. A method for the production of a flavour granule for a smoking article, the method comprising the steps of: forming an inner core by compaction of particles of herbaceous plant material; providing a coating suspension comprising between 20 percent and 30 percent by weight of coloured binder particles comprising at least one colourant and at least one polymeric binder in a solvent; applying the coating suspension to an outer surface of the inner core to form an outer layer, wherein the coating suspension is applied to the inner core within a coating system and wherein within that coating system the vapour pressure of the solvent is greater than 5 kPa; and drying the outer layer to evaporate the solvent.

2. A method according to claim 1 wherein the solvent is an organic solvent having a boiling point of less than 85 degrees Celsius.

3. A method according to claim 1 wherein the step of applying the coating suspension to the inner core is carried out in a fluidised bed apparatus.

4. A method according to claim 1 wherein a solids content of the coating suspension is at least 20 percent by weight.

5. A method according to claim 1 wherein the drying step is carried out using a flow of air at a temperature of less than 25 degrees Celsius.

6. A method according to claim 2 wherein the step of applying the coating suspension to the inner core is carried out in a fluidised bed apparatus.

7. A method according to claim 2 wherein a solids content of the coating suspension is at least 20 percent by weight.

8. A method according to claim 3 wherein a solids content of the coating suspension is at least 20 percent by weight.

9. A method according to claim 2 wherein the drying step is carried out using a flow of air at a temperature of less than 25 degrees Celsius.

10. A method according to claim 6 wherein a solids content of the coating suspension is at least 20 percent by weight.

11. A method according to claim 10 wherein the drying step is carried out using a flow of air at a temperature of less than 25 degrees Celsius.

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 side view of a filter cigarette containing flavour granules obtained by methods according to the present invention, comprising a single segment filter (first arrangement); and

(3) FIG. 2 shows a side view of a filter cigarette containing flavour granules obtained by methods according to the present invention, comprising a multi-component filter (alternative arrangement).

(4) In each of the side views, portions have been broken away to illustrate interior details of the filter.

(5) The filter cigarette 10 of FIG. 1 comprises an elongate, cylindrical wrapped tobacco rod 12 attached at one end to an axially aligned, elongate, cylindrical, filter 14.

(6) The filter 14 of the filter cigarette 10 is a single segment filter consisting of a flavour release segment 16 adjacent to and abutting the wrapped tobacco rod 12.

(7) The flavour release segment 16 comprises a plug of cellulose acetate tow with a plurality of green flavour granules substantially evenly distributed therein. The flavour release segment 16 is wrapped with a substantially transparent plug wrap 18.

(8) The wrapped tobacco rod 12 and the wrapped filter 14 are joined by an outer wrapper 20 formed of tipping paper, which circumscribes the entire length of the filter 14 and an adjacent portion of the tobacco rod 12. The outer wrapper 20 comprises a circular cut-out portion 22 having a diameter of approximately 5 mm which is positioned approximately 5 mm from the rod end of the outer wrapper. The underlying substantially transparent plug wrap 18 is exposed through the cut-out portion 22 in the outer wrapper 20 and an area of the flavor release segment 16 including the green flavor granules is therefore visible through the cut-out portion 22.

(9) Circumferential rows of perforations 24 are provided approximately 12 mm from the mouth end of the cigarette 10.

(10) To form the filter cigarette 10 the filter 14 is produced and then joined to the wrapped tobacco rod 12, which is produced in a conventional manner, by the tipping paper 16 using known filter cigarette making equipment.

(11) The filter cigarette 30 shown in FIG. 2 comprises an elongate, cylindrical wrapped tobacco rod 32 attached at one end to an axially aligned, elongate, cylindrical, filter 34. The filter 34 of the cigarette 30 is a multi-component filter 34 that includes three segments in abutting end-to-end relationship: a mouth end segment 36, distant from the tobacco rod 32; a flavour release segment 38 located upstream of the mouth end segment; and a rod end segment 40, located upstream of the flavour release segment 38 and adjacent to and abutting the wrapped tobacco rod 32.

(12) The mouth end segment 36 comprises a plug of cellulose acetate tow of low filtration efficiency plasticised with glycerol triacetate.

(13) The flavour release segment 38 comprises a cavity containing a plurality of green flavour granules.

(14) The rod end segment 40 comprises a plug of cellulose acetate tow of medium to high filtration efficiency that, in use, partially filters out particulate phase components of the mainstream smoke.

(15) The wrapped tobacco rod 32 and the multi-component filter 34 are joined in a conventional manner by tipping paper 42, which circumscribes the entire length of the multi-component filter and an adjacent portion of the wrapped tobacco rod 32. To ventilate mainstream smoke produced during combustion of the wrapped tobacco rod 32 with ambient air, a plurality of annular perforations 44 are provided through the tipping paper 42 at a location along the multi-component filter 34.

(16) To produce the multi-component filter 34 of the filter cigarette 30 shown in FIG. 2, separate continuous rods comprising multiple units of each segment 36, 40 of the multi-component filter 34 are produced in a known manner. The segments 36, 40 are then placed in a plug wrap material in a manner that creates a space between the segments 36, 40. The space is filled with the granules and then the plug wrap material is wrapped around the segments 36, 40, enclosing the granules within the space.

(17) In each of the filters 14, 34 the flavour release segment 16, 38 contains a plurality of flavour granules having a total weight of approximately 25 mg. The flavour granules are cylindrical and have an average largest dimension of about 0.8 mm. Each flavour granule comprises an inner core formed of compacted particles of mint leaf, and a porous outer layer of coloured binder particles. Suitable flavour granules may be produced according to the example set out below.

EXAMPLE

(18) The inner core of the flavour granules is formed from mint leaf, which has first been cut to a particle size of between 0.2 mm and 0.5 mm before being sprayed with steam to increase the moisture content of the mint leaf to between 35 percent and 45 percent oven volatiles. The wet mass of cut mint leaf is then extruded through a screw extruder to compact the mint leaf in order to increase the density, as well as shaping the mint leaf into the desired cross-sectional shape for the granules. The result extruded mass of mint leaf granules is then cut to form the inner core having a size of around 0.8 mm and the inner core is allowed to dry at room temperature.

(19) After drying, the inner core is sprayed with a liquid coating suspension including 75 percent by weight of ethyl acetate solvent and 25 percent by weight of coloured binder particles comprising a green pigment supported on an ethyl cellulose binder. The green pigment may be formed from a mixture of Tartrazin (E102) and Indigotin I (E132), or a mixture of Sunset Yellow FCF (E110) and Indigotin I (E132). The spraying is carried out in a Mini Glatt fluidised bed sprayer with an air temperature of 24 degrees Celsius, an air pressure of 0.89 Bar and a liquid flow rate of 1 gram per minute for 5 minutes. The amount of the liquid coating suspension applied to the fluidised inner cores corresponds to about 10 percent by weight of the total weight of the inner cores.

(20) The solvent is evaporated from the coated inner cores using a stream of air in the fluidised bed sprayer.

(21) A menthol analysis conducted on a sample of flavour granules produced according to this example demonstrated that the menthol content by weight of the flavour granules including the permeable outer layer was within 0.1 percentage points of the menthol content of the inner cores prior to the application of the outer layer. This indicates that the loss of menthol from the inner cores as a result of the additional processing required to apply the porous outer layer is minimal.