Smoking article with liquid release component having frangible shell

Abstract

A smoking article (10) incorporates a liquid release component (20), the liquid release component comprising an inner core of a sustained release liquid delivery material and a frangible outer shell encapsulating the inner core. The liquid delivery material comprises a closed matrix structure comprising a cross-linked polymer matrix defining a plurality of domains; and a liquid composition that is trapped within the domains and is releasable from the closed matrix structure upon compression of the material. The frangible outer coating comprises at least one film-forming polymer and at least one plasticiser.

Claims

1. A smoking article incorporating a liquid release component, the liquid release component comprising: an inner core of a sustained release liquid delivery material comprising: a closed matrix structure comprising a cross-linked polymer matrix defining a plurality of domains; and a liquid composition that is trapped within the domains and is releasable from the closed matrix structure upon compression of the material, wherein the liquid delivery material provides a sustained release of the liquid composition upon compression of the material over a range of force of at least 5 Newtons; and a frangible outer shell encapsulating the inner core of liquid delivery material, the frangible outer shell comprising at least one film-forming polymer comprising at least 80 percent by weight and at least one plasticizer comprising less than 12 percent by weight, based on total dry weight of the frangible outer shell.

2. A smoking article according to claim 1 wherein the at least one film-forming polymer in the outer shell comprises a polyester film-forming polymer, a cellulosic film-forming polymer or a combination thereof.

3. A smoking article according to claim 1 wherein the at least one film-forming polymer in the outer shell comprises a starch based film-forming polymer.

4. A smoking article according to claim 1 wherein the average thickness of the outer shell corresponds to at least 2 percent of a maximum diameter of the inner core.

5. A smoking article according to claim 1 wherein the outer shell has an average thickness of between 25 microns and 500 microns.

6. A smoking article according to claim 1 wherein the outer shell corresponds to at least 5 percent by weight based on the total dry weight of the liquid release component.

7. A smoking article according to claim 1 wherein a force/displacement curve obtained upon compression of the liquid release component within the smoking article in a force/displacement test comprises a plurality of local minima in a force level over a range of compression of at least 1 mm, wherein each of the local minima corresponds to a reduction in the force level of at least 1 Newton.

8. A smoking article according to claim 7 wherein an acoustic signal detected upon compression of the liquid release component during the force/displacement test comprises an elevated phase in which a plurality of acoustic peaks having an elevated decibel level of at least 65 decibels are detected, wherein the elevated phase extends over a range of compression of at least 1 mm.

9. A smoking article according to claim 7 wherein the range of compression over which the local minima in the force level are detected corresponds to at least 20 percent of a dimension of the liquid release component in the direction of the applied force.

10. A smoking article according to claim 1 wherein a maximum diameter of the liquid release component corresponds to at least 30 percent of a maximum diameter of the smoking article at the position of the liquid release component.

11. A filter for a smoking article comprising a liquid release component, the liquid release component comprising: an inner core of a sustained release liquid delivery material comprising: a closed matrix structure comprising a cross-linked polymer matrix defining a plurality of domains; and a liquid composition that is trapped within the domains and is releasable from the closed matrix structure upon compression of the material, wherein the liquid delivery material provides a sustained release of the liquid composition upon compression of the material over a range of force of at least 5 Newtons; and a frangible outer shell encapsulating the inner core of liquid delivery material, the frangible outer shell comprising at least one film-forming polymer comprising at least 80 percent by weight, based on total dry weight of the frangible outer shell, and at least one polysaccharide filler.

12. A flavour release component for a smoking article, the flavour release component comprising: an inner core of a sustained release flavour delivery material comprising: a closed matrix structure comprising a cross-linked polymer matrix defining a plurality of domains; and a flavour composition that is trapped within the domains and is releasable from the closed matrix structure upon compression of the material, wherein the flavour delivery material provides a sustained release of the flavour composition upon compression of the material over a range of force of at least 5 Newtons; and a frangible outer shell encapsulating the inner core of flavour delivery material, the frangible outer shell comprising at least one film-forming polymer comprising at least 80 percent by weight and at least one plasticizer comprising less than 12 percent by weight, based on total dry weight of the frangible outer shell.

13. A method of producing a flavour release component according to claim 12, the method comprising the steps of: forming a flavour composition by dispersing a flavourant in one or more fats that are liquid at a temperature of approximately 22 C.; mixing the flavour composition with a matrix solution comprising one or more polysaccharides to form an emulsion; adding the emulsion to a cross-linking solution to cross-link the polysaccharides to form an inner core having a polymer matrix including a plurality of domains having the flavour composition within the domains; coating the inner core with a coating solution comprising at least one film-forming polymer and at least one plasticiser; and drying the coated inner core to form a flavour release component having a frangible outer shell.

Description

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

(2) FIG. 1 shows a side view of a filter cigarette according to the present invention comprising a flavour release component in the filter; and

(3) FIG. 2 shows the force/displacement curve and acoustic signal obtained during a force/displacement test on the smoking article of FIG. 1.

(4) The cigarette 10 shown in FIG. 1 comprises an elongate, cylindrical wrapped tobacco rod 12 attached at one end to an axially aligned, elongate, cylindrical filter 14. The filter 14 includes a single segment of cellulose acetate tow. The wrapped tobacco rod 12 and the filter 14 are joined in a conventional manner by tipping paper 16, which circumscribes the entire length of the filter 14 and an adjacent portion of the wrapped tobacco rod 12. To mix ambient air with mainstream smoke produced during combustion of the wrapped tobacco rod 12, a plurality of annular perforations 18 are provided through the tipping paper 16 at a location along the filter 14.

(5) A single flavour bead 20 formed of a coated flavour delivery material, as described above, is provided centrally within the filter 14. The flavour bead 20 has a diameter of around 4 mm and has a structure comprising an inner core of flavour delivery material and a frangible outer shell around the inner core. The flavour delivery material in the bead 20 incorporates a flavour composition comprising a menthol flavourant, which is released upon compression of the material with a force of between about 5 Newtons and about 10 Newtons. After compression, the menthol flavourant is available for release into the mainstream smoke as the smoke passes through the filter during smoking.

(6) The amount of flavour composition released from the flavour delivery material depends upon the applied compressive force such that the flavour intensity can be controlled through control of the pressure applied to the filter. The flavour bead can be compressed one or more times prior to or during smoking in order to provide a burst of menthol flavour to the smoke.

(7) Examples of suitable formulations for the flavour bead and a process for forming the flavour bead are set out below.

EXAMPLE 1

(8) The inner core of the flavour bead is formed of a flavour delivery material comprising a cross-linked alginate matrix with a plurality of domains of a menthol flavour composition dispersed through the matrix. To produce the inner core of flavour delivery material, the menthol flavour composition is first formed from a mixture of the following components:

(9) TABLE-US-00001 Amount Component (weight percent) Natural L-menthol 26.07 MCT Oil (MYGLIOL 810) 72.05 Other flavour 1.88

(10) The mixing is conducted with magnetic agitation at a temperature of 30 degrees Celsius for a period of 20 minutes.

(11) A matrix solution is then formed from a mixture of the following components:

(12) TABLE-US-00002 Amount Component Function (weight percent) Sodium alginate Anionic 2.36 polysaccharide OSA-modified corn starch Amphiphilic 0.67 polysaccharide filler Glycerol Plasticiser 0.34 Sorbitol Plasticiser 0.34 Water Solvent 96.29

(13) As the amphiphilic polysaccharide filler, OSA-modified corn starch HI-CAP 100 (commercially available from National Starch & Chemical, Manchester UK) is used. HI-CAP 100 is an OSA-modified starch derived from waxy maize. Due to the hydrophobic and steric properties imparted by OSA, HI-CAP 100 is structurally significantly different from a natural starch, such as Merizet 100 starch (commercially available from Tate & Lyle), and displays, accordingly, different chemical-physical properties, including in particular interfacial and rheological properties.

(14) The mixing is conducted with a marine impeller operating at 1500 revolutions per minute and at a temperature of less than 30 degrees Celsius. The mixing is continued for 30 minutes.

(15) A solution then is formed with 30 percent w/w of the flavour composition and 70 percent w/w of the matrix solution. The solution is mixed in a shear mixer, such as a Polytron 3100B, available from Kinematica. The solution is subjected to high shear at an RPM of 15000 to 20000 whilst maintaining the mixture at a temperature of 52-55 degrees Celsius. The mixing is continued for 3 to 4 minutes to produce an emulsion of the flavour composition in the matrix polymer solution in which the size of the flavour composition droplets is reduced to below about 10 to 50 microns.

(16) The emulsion is then added to a cross-linking solution of the following composition to form the polymer matrix having the plurality of domains.

(17) TABLE-US-00003 Amount Component (weight percent) Calcium chloride 5.0 Water 95.0

(18) The emulsion is dripped into a bath of the cross-linking solution to form a flavour delivery material in the form of spheres which provide the inner core of the flavour beads. The emulsion is added drop-by-drop through a nozzle using a peristaltic pump. The emulsion is dropped through a 5 millimetre nozzle at a flow rate of 500 grams per hour. The process is carried out at room temperature and the bath of cross-linking solution is agitated using a magnetic mixer at a speed of 100 revolutions per minute. The emulsion and the cross-linking solution are allowed to react for a period of ten minutes.

(19) The inner cores are then removed from the cross-linking solution and washed in deionised water before being dried in a stream of dried air at a temperature of about 25 degrees Celsius for at least 360 minutes.

(20) The number average weight of each inner core of flavour delivery material is 29.1 milligrams and the number average diameter of each bead is 3.94 mm. The average water content of each bead is between about 4 percent and about 6 percent by weight and the average menthol content of each bead is approximately 20 to 25 percent by weight.

(21) Once dried, the inner cores are coated with a coating solution formed of an aqueous solution of the following mixture of compounds in water:

(22) TABLE-US-00004 Amount Component Function (weight percent) Shellac Film-forming polymer 72.0 Corn starch Film-forming polymer 19.9 Xylitol Plasticiser 4.8 Glycerol Plasticiser 3.3

(23) The solution contains about 30 percent by weight of the compounds above and 70 percent by weight of water. The mixing of the coating solution is conducted with magnetic agitation at a temperature of 30 degrees Celsius for a period of 20 minutes.

(24) The coating solution is then applied to the inner cores in a Mini Glatt fluidised bed sprayer with an air temperature of 40-45 degrees Celsius, an atomisation pressure of 3 Bar and a liquid flow rate of 8 gram per minute for 5 minutes. The amount of the liquid coating solution applied to the fluidised inner cores corresponds to about 25 percent by weight of the total weight of the inner cores.

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

(26) The number average weight of each coated inner core (after drying) is 32.2 milligrams and the number average diameter of each bead is 4.1 mm. The average water content of each bead is between about 2 percent and about 3 percent by weight.

(27) A force/displacement test was carried out on the smoking article including the flavour bead using a Texture Analyser and Acoustic Envelope Detector from Stable Micro Systems as detailed above. The smoking article was compressed, at the position of the flavour bead, with a compression rate of 10 mm per minute up to a compression of 5 mm. The force required was plotted as a function of the compression distance in a force/displacement curve, as shown in FIG. 2. During the force/displacement test, the acoustic emission from the smoking article was detected and plotted as a function of the compression distance, as shown in FIG. 2.

(28) As can be seen from FIG. 2, the force/displacement curve 30 includes a plurality of force drops 32 of at least 1 Newton. The acoustic signal 40 comprises an initial phase in which the acoustic output is relatively flat and an elevated phase starting at a compression distance of approximately 2.5 mm, in which a plurality of acoustic peaks 42 having an acoustic level above 65 decibels were detected. The elevated phase extends to a compression distance of approximately 4.5 mm and therefore corresponds to a range of compression of approximately 2 mm. Within the elevated phase, the acoustic signal further comprises a region 44 between approximately 2.5 mm and 3.5 mm in which the acoustic level is sustained above 55 decibels.

(29) The acoustic signal and force/displacement curve demonstrate the sustained crunchiness of the outer shell upon compression, as described in detail above.

EXAMPLE 2

(30) The inner core of the flavour bead is formed as described above for Example 1. Once dried, the inner cores are coated with a coating solution formed of an aqueous solution of the following mixture of compounds:

(31) TABLE-US-00005 Amount Component Function (weight percent) Shellac Film-forming polymer 87.5 Methyl hydroxypropyl Film-forming polymer 7.4 cellulose Glycerol Plasticiser 5.1

(32) The solution contains about 20 percent by weight of the compounds above and 80 percent by weight of water.

(33) The coating solution is applied to the inner cores as described above. The amount of the liquid coating solution applied to the fluidised inner cores corresponds to about 27 percent by weight of the total weight of the inner cores.

(34) The number average weight of each coated inner core (after drying) is 32.4 milligrams and the number average diameter of each bead is 4.0 mm. The average water content of each bead is between about 2 percent and about 3 percent by weight.

EXAMPLE 3

(35) The inner core of the flavour bead is formed as described above for Example 1. Once dried, the inner cores are coated with a coating solution formed of an aqueous solution of the following mixture of compounds:

(36) TABLE-US-00006 Amount Component Function (weight percent) Methyl hydroxypropyl Film-forming polymer 22.2 cellulose Corn starch Film-forming polymer 66.7 Glycerol Plasticiser 11.1

(37) The solution contains about 20 percent by weight of the compounds above and 80 percent by weight of water.

(38) The coating solution is applied to the inner cores as described above. The amount of the liquid coating solution applied to the fluidised inner cores corresponds to about 14 percent by weight of the total weight of the inner cores.

(39) The number average weight of each coated inner core (after drying) is 31.4 milligrams and the number average diameter of each bead is 4.0 mm. The average water content of each bead is between about 2 percent and about 3 percent by weight.