Smoking article with liquid delivery material

Abstract

A smoking article (10) incorporates a sustained release liquid delivery material (20), the liquid delivery material comprising a closed matrix structure defining a plurality of domains. A liquid composition is trapped within the domains and is releasable from the closed matrix structure upon compression of the material. The liquid delivery material (20) provides a sustained release of the liquid composition over a range of force of at least 5 Newtons. Preferably, the liquid delivery material is provided within the filter (14) of the smoking article (10).

Claims

1. A smoking article incorporating a sustained-release liquid delivery material, the liquid delivery material comprising: a closed matrix structure defining a plurality of closed pores; and a liquid composition that is trapped within the closed pores and is releasable from the closed matrix structure upon compression of the liquid delivery material, wherein the liquid delivery material provides a sustained release of the liquid composition upon compression of the liquid delivery material over at least a 5 Newton range of force.

2. A smoking article according to claim 1 wherein the liquid delivery material provides a sustained release of the liquid composition upon compression of the liquid delivery material over a range of force from 10 Newtons to 15 Newtons.

3. A smoking article according to claim 2 wherein an amount of the liquid composition released from the liquid delivery material upon compression of the liquid delivery material with a force of 5 Newtons corresponds to at least 2 percent by weight of the liquid delivery material prior to any compression and wherein an additional amount of the liquid composition that is released upon further compression of the liquid delivery material with a force of 10 Newtons to a total force of 15 Newtons corresponds to at least 10 percent by weight of the liquid delivery material prior to any compression.

4. A smoking article according to claim 2 wherein an amount of the liquid composition released from the liquid delivery material upon compression of the liquid delivery material with a force of 10 Newtons corresponds to at least 20 percent by weight of the liquid delivery material prior to any compression and wherein an additional amount of the liquid composition that is released upon further compression of the liquid delivery material with a force of 15 Newtons to a total force of 25 Newtons corresponds to at least 10 percent by weight of the liquid delivery material prior to any compression.

5. A smoking article according to claim 1 wherein an amount of the liquid composition released from the liquid delivery material upon compression of the liquid delivery material with a force of 5 Newtons corresponds to at least 2 percent by weight of the liquid delivery material prior to any compression and wherein an additional amount of the liquid composition that is released upon further compression of the liquid delivery material with a force of 10 Newtons to a total force of 15 Newtons corresponds to at least 10 percent by weight of the liquid delivery material prior to any compression.

6. A smoking article according to claim 5 wherein an amount of the liquid composition released from the liquid delivery material upon compression of the liquid delivery material with a force of 10 Newtons corresponds to at least 20 percent by weight of the liquid delivery material prior to any compression and wherein an additional amount of the liquid composition that is released upon further compression of the liquid delivery material with a force of 15 Newtons to a total force of 25 Newtons corresponds to at least 10 percent by weight of the liquid delivery material prior to any compression.

7. A smoking article according to claim 1 wherein an amount of the liquid composition released from the liquid delivery material upon compression of the liquid delivery material with a force of 10 Newtons corresponds to at least 20 percent by weight of the liquid delivery material prior to any compression and wherein an additional amount of the liquid composition that is released upon further compression of the liquid delivery material with a force of 15 Newtons to a total force of 25 Newtons corresponds to at least 10 percent by weight of the liquid delivery material prior to any compression.

8. A smoking article according to claim 1 wherein the liquid delivery material provides a sustained release of the liquid composition upon compression of the liquid delivery material over at least a 25 percent range of deformation.

9. A smoking article according to claim 1 wherein an amount of the liquid composition released from the liquid delivery material upon compression of the liquid delivery material to a 10 percent deformation corresponds to at least 2 percent by weight of the liquid delivery material prior to any compression and wherein an additional amount of the liquid composition that is released upon further compression of the liquid delivery material to a 40 percent deformation corresponds to at least 10 percent by weight of the liquid delivery material prior to any compression.

10. A smoking article according to claim 1, wherein the liquid delivery material comprises a sustained release flavour delivery material comprising a flavour composition.

11. A smoking article according to claim 1, wherein the liquid delivery material is a flavour delivery material, wherein the closed matrix structure is a polymer matrix comprising one or more matrix-forming polymers and a plasticiser, and wherein the liquid composition trapped within the plurality of closed pores defined by the polymer matrix is a flavour composition, the flavour composition comprising a flavourant mixed with one or more fats that are liquid at 22 C.

12. A smoking article according to claim 11 wherein the flavour composition of the flavour delivery material comprises a fat including at least 30 percent by weight of medium chain triglycerides having at least one carboxylic acid having a chain length of between 6 and 12.

13. A smoking article according to claim 12 wherein the plasticiser in the polymer matrix of the flavour delivery material comprises at least one of polyethylene glycol and glycerol.

14. A smoking article according to claim 11 wherein the plasticiser in the polymer matrix of the flavour delivery material comprises at least one of polyethylene glycol and glycerol.

15. A smoking article according to claim 14 wherein the amount of plasticiser in the polymer matrix corresponds to at least 5 percent by weight of the matrix-forming polymers.

16. A smoking article according to claim 11 wherein the amount of plasticiser in the polymer matrix corresponds to at least 5 percent by weight of the matrix-forming polymers.

17. A smoking article according to claim 11 wherein the matrix-forming polymers in the polymer matrix of the flavour delivery material include at least one of alginate and pectin.

18. A smoking article according to claim 1 wherein the liquid composition comprises menthol.

19. A smoking article according to claim 1 comprising a filter including the liquid delivery material.

20. The smoking article according to claim 1, wherein the closed matrix structure comprises a cross-linked polymer.

21. The smoking article according to claim 20, wherein the cross-linked polymer comprises a polysaccharide.

22. A filter for a smoking article comprising a sustained-release flavour delivery material, the flavour delivery material comprising: a closed matrix structure defining a plurality of closed pores; and a flavour composition that is trapped within the closed pores and is releasable from the closed matrix structure upon compression of the flavour delivery material, wherein the flavour delivery material provides a sustained release of the flavour composition upon compression of the flavour delivery material over at least a 5 Newton range of force.

23. The filter for a smoking article according to claim 22, wherein the closed matrix structure comprises a cross-linked polymer.

24. The filter for a smoking article according to claim 23, wherein the cross-linked polymer comprises a polysaccharide.

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 according to the present invention comprising a flavour delivery material in the tobacco rod; and

(3) FIG. 2 shows a scanning electron microscope image of the flavour delivery material used in the filter cigarette 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 sustained release flavour delivery material, as described above, is provided centrally within the filter 14. The flavour bead 20 has a diameter of around 2.5 mm. 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 delivery material 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) An example of a suitable formulation for the flavour delivery material forming the bead and a process for forming the flavour delivery material is set out below.

EXAMPLE 1

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

(9) TABLE-US-00001 Amount (weight Component percent) Natural L-menthol 28 MCT Oil (MYGLIOL 810) 70 Other flavour 2

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

(11) TABLE-US-00002 Amount (weight Component percent) Sodium alginate 2.47 (available from Sigma Aldrich) Citrus Pectin 0.96 (available from Sigma Aldrich) Polyethylene glycol 1500S 0.27 Water 96.30

(12) A solution is formed with 20 percent w/w of the flavour composition and 80 percent w/w of the matrix polymer solution. The solution is mixed in a shear mixer, such as a Polytron 3100B equipped with a dispersing aggregate head PT-DA 3030/4 EC with a diameter of 30 mm, 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 C. 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 20 to 40 microns.

(13) The resultant emulsion is formed into the shape of spherical beads and dropped into a cross-linking solution of the following composition, at a temperature of 4 C.:

(14) TABLE-US-00003 Amount (weight Component percent) Calcium chloride 5.0 (available from Sigma Aldrich) Water 95.0

(15) The beads are left in the cross-linking solution for approximately 60 seconds in order to cross-link the alginate and pectin to form the polymer matrix. The beads are then removed from the cross-linking solution and washed in water before being dried in hot dried air at a temperature of 40-50 C. for 300 minutes.

(16) FIG. 2 shows a scanning electron microscope image of the flavour delivery material produced in the above example. It can be seen from the image that the internal structure of the flavour delivery material is provided by a polymer matrix with a plurality of small domains of the flavour composition dispersed through the matrix.

(17) The sustained release profile of the bead of flavour delivery material may be analysed in a flexure test. In the flexure test, a bead of flavour delivery material of a known weight is mounted on a base plate and compressed by a flat compression head having an area that is greater than the area of the bead. The compression head exerts a compressive force in a downwards direction onto the bead. During the flexure test, the compression head is brought into contact with the bead and moved downwards by a defined distance or force, referred to as the flexure distance or force.

(18) The force required to move the compression head by the defined flexure distance is measured. The percentage deformation of the bead at the flexure distance of the compression head corresponds to the flexure divided by the initial diameter of the bead, multiplied by 100 percent. After compression, the bead is removed from the compression apparatus and the amount of flavour composition that has been released from the flavour delivery material as a result of the applied compressive force is measured.

(19) The amount of released flavour composition can be estimated as follows. After removal from the compression apparatus, the bead is wiped with tissue or another non-abrasive, absorbent paper material in order to remove as much of the flavour composition from the ruptured domains as possible. The bead is then weighed to determine the approximate weight of the flavour composition that has been released from the material as a result of the applied compression by comparing the measured weight with the original weight of the bead. For the present purposes, it is assumed that the measured weight loss from the bead corresponds to the amount of the flavour composition that is released.

(20) A sequence of similar tests is then carried out with the compression head moved downwards by different defined flexure distances.

(21) The measured deformation and percent weight loss from the beads at different compressive forces were found to vary as shown in the table below. For each flexure distance, the values indicate corresponds to the average mean values from identical tests carried out on 5 beads.

(22) TABLE-US-00004 Flexure Force Deformation Weight loss (mm) (N) (%) (%) 0.3 8.75 12 3 0.6 9.44 24 9 0.9 12.19 36 16 1.2 17.73 48 28 1.4 13.6 56 33

(23) As can be seen from the results above, an increasing amount of flavour composition is released from the flavour delivery material at high compressive forces and higher levels of deformation. The results illustrate that the bead is capable of sustained release of the flavour composition over a range of compressive force of around 9 Newtons. The results additionally illustrate that the bead is capable of sustained released of the flavour composition over a range of deformation of around 30 percent.

(24) In certain circumstances, it may be desired to measure the amount of flavour composition released from the same bead at two or more different compressive forces in order to determine the flavour release profile of a single bead. In that case, the flexure test described above is carried out on a bead with a first applied compressive force and after weighing of the bead to determine the loss of flavour composition, the same bead is tested again with a second compressive force. In both tests, the procedure as described above is followed, the only difference being that a single bead is used for both tests.

EXAMPLE 2

(25) The flavour delivery material comprises a cross-linked alginate matrix with a plurality of domains of a menthol flavour composition dispersed through the matrix. The flavour delivery material is prepared using processes similar to those described above in Example 1.

(26) The flavour composition is formed by dispersing menthol and flavour in a lipophilic phase made of a medium chain triglyceride (Miglyol 812N).

(27) A hydrophilic polymer solution is then formed from alginate (Algogel 3001), corn starch (Merizet 100) and a plasticiser (polyethylene glycol (PEG) or glycerol), and mixed with the flavour composition to form an emulsion. The mixing is conducted in an Ultra-turrax apparatus operating at 10000 revolutions per minute and at a temperature of less than 30 degrees Celsius.

(28) The emulsion is then added to a cross-linking solution comprising calcium chloride to form the polymer matrix having the plurality of domains. The emulsion is dripped into a bath of the cross-linking solution to form a flavour delivery material in the form of beads. The emulsion is added drop-by-drop through a nozzle using a peristaltic pump. The emulsion is dropped from a height of 30 centimeters through a 4.4 millimeter 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.

(29) Two batches of flavour delivery material were produced for this Example 2, the batches having the following compositions:

(30) TABLE-US-00005 Batch 1 Amount (weight Component percent) Algogel 3001 8.3 Merizet 100 2.9 Glycerol 1.9 Miglyol 812N 60.7 Menthol 24.4 Other flavour 1.8

(31) TABLE-US-00006 Batch 2 Amount (weight Component percent) Algogel 3001 8.2 Merizet 100 5.6 PEG 1.8 Miglyol 812N 57.8 Menthol 24.8 Other flavour 1.8

(32) For batch 1, the number average weight of each bead of flavour material is 17.3 milligrams and the number average diameter of each bead is 3.4 millimeters. The average water content of each bead is 3.3% by weight and the average menthol content of each bead is approximately 4 milligrams.

(33) For batch 2, the number average weight of each bead of flavour material is 16.3 milligrams and the number average diameter of each bead is 3.4 millimeters. The average water content of each bead is 4.0% by weight and the average menthol content of each bead is 3.2 milligrams.

(34) A number of test cigarettes were formed by taking a plurality of standard cigarettes (circumference 25 millimeters, tipping length 32 millimeters, filter plug length 27 millimeters, tobacco rod length 57 millimeters, total length 84 millimeters) and removing the filter plug and the plug wrap from each cigarette, therefore leaving a hollow tipping paper tube attached to the tobacco rod. A new filter plug was cut to a length of 27 millimeters and the plug wrap removed. A slight incision was made in the filter plug using a scalpel and one bead of the flavour delivery material from either batch 1 or batch 2 was inserted into the filter plug such that the axial distance between the mouth end of the filter plug and the centre of the bead was 13.5 millimeters. A new filter plug, without a plug wrap, was then inserted into the hollow tipping paper tube of each cigarette to form the plurality of test cigarettes. For test cigarettes containing a bead from batch 1, the average resistance to draw of each test cigarette was 93 mmWG and the average ventilation of each test cigarette was 55%. For test cigarettes containing a bead from batch 2, the average resistance to draw of each test cigarette was 91 mmWG and the average ventilation of each test cigarette was 54%. Resistance to draw is measured using the test procedure described in ISO 6565:2002 and ventilation is measured using ISO 9512:2002.

(35) A panel of five smoking experts conducted a qualitative test of the test cigarettes containing beads from batch 2. It was found that no minty note and no cooling sensation were perceived without compression of the beads. After several compressions a cooling, minty note was perceived by the panellists. The panellists noted that as more pressure was applied to the beads, the cooling sensation and minty notes increased.

(36) The test cigarettes containing beads from batch 1 were tested to measure the menthol in smoke (MIS) when subjected to a smoking test after varying degrees of compression.

(37) Firstly, the test cigarettes were grouped into sample sets each comprising 20 cigarettes. Each sample set was conditioned at 22 degrees Celsius and 60% relative humidity, and then each sample set was subjected to a compressive force applied simultaneously to the 20 cigarettes in each sample set. Each set was subjected to one of the following compressive forces: 0 Newtons; 700 Newtons per twenty cigarettes; 900 Newtons per 20 cigarettes; 1100 Newtons per 20 cigarettes; and 1300 Newtons per 20 cigarettes. The compressive force was applied using an Instron Instrument modified with a tool for compressing 20 cigarettes simultaneously. Two minutes after applying the compressive force, each sample set was smoked using a standard smoking test. Specifically, each smoking article was subjected to a standard smoking test under ISO conditions (35 ml puffs lasting 2 seconds each, every 60 seconds), with the ventilation zone fully uncovered. The total amount of menthol contained in the smoke from the cigarettes was measured and the test procedure repeated at each compressive force for a second set of 20 cigarettes. An average value for the amount of menthol contained in the smoke from each cigarette was calculated as follows:

(38) TABLE-US-00007 Compressive force (Newtons Average menthol in smoke per 20 cigarettes) (milligrams per cigarette) 0 0 700 0.34 900 0.405 1100 0.4 1300 0.425

(39) As can be seen from the table above, with the matrix material used in these tests, the amount of menthol released does not vary linearly with the compressive force applied.

(40) After the smoking tests were completed, the cigarette butts were cut open and the beads removed and weighed. As shown below, the greater the compressive force applied to each bead prior to the smoking test, the smaller the residual weight of the bead after the smoking test due to the release of menthol into the cigarette. A summary of the average residual weight of the beads after being subjected to compression and the smoking test is as follows:

(41) TABLE-US-00008 Average residual weight of Compressive force (Newtons each bead after the smoking per 20 cigarettes) test (milligrams) 0 17.16 700 11.61 900 10.54 1100 9.66 1300 9.02