Aerosol-generating article having novel tobacco substrate

Abstract

A heated aerosol-generating article is provided, including an aerosol-forming substrate including tobacco and a metal-based sulphide scavenger compound, an amount of a metal component of the sulphide scavenger compound in the aerosol-forming substrate is at least 0.05 percent by weight, based on a total dry weight of the aerosol-forming substrate, and the sulphide scavenger compound is based on a transition metal.

Claims

1. A heat-not-burn article, comprising: an aerosol-forming substrate comprising a sheet of homogenised tobacco material, the homogenised tobacco material comprising tobacco, an aerosol former, and a sulphide scavenger compound based on a transition metal selected from zinc or copper, wherein an amount of a transition metal component of the sulphide scavenger compound in the aerosol-forming substrate is at least 0.05 percent by weight, based on a total dry weight of the aerosol-forming substrate, wherein the sulphide scavenger compound is a transition metal salt selected from a carbonate, sulphate, hydroxide, malate, acetate, or bromide.

2. The heat-not-burn article according to claim 1, wherein the amount of the transition metal component of the sulphide scavenger compound is between 0.05 percent and 5 percent by weight based on the total dry weight of the aerosol-forming substrate.

3. The heat-not-burn article according to claim 2, wherein the amount of the transition metal component of the sulphide scavenger compound is between 0.25 percent and 2.5 percent by weight based on the total dry weight of the aerosol-forming substrate.

4. The heat-not-burn article according to claim 1, wherein the amount of the transition metal component of the sulphide scavenger compound is at least 0.1 percent by weight based on the total dry weight of the aerosol-forming substrate.

5. The heat-not-burn article according to claim 1, wherein the sulphide scavenger compound in the aerosol-forming substrate provides a reduction of at least 50 percent by weight of hydrogen sulphide during a pre-heating test compared with an equivalent aerosol-generating article without the sulphide scavenger compound in the aerosol-forming substrate, and wherein in the pre-heating test a heating element configured to heat the aerosol-forming substrate in the heat-not-burn article is programmed to heat at 350 degrees Celsius for 30 seconds and then to switch off.

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 is a schematic cross-sectional view of an aerosol-generating article according to an embodiment of the invention;

(3) FIG. 2 is a schematic cross-sectional view of an aerosol-generating system comprising an aerosol-generating device and an aerosol generating article according to the embodiment illustrated in FIG. 1; and

(4) FIG. 3 is a schematic cross-sectional view of the electrically heated aerosol generating device of FIG. 2.

(5) The aerosol-generating article 10 shown in FIG. 1 comprises four elements arranged in coaxial alignment: an aerosol-forming substrate 20, a support element 30, an aerosol-cooling element 40, and a mouthpiece 50. Each of the four elements is circumscribed by a corresponding plug wrap (not shown). These four elements are arranged sequentially and are circumscribed by an outer wrapper 60 to form the aerosol-generating article 10. The aerosol-generating 10 has a proximal or mouth end 70, which a user inserts into his or her mouth during use, and a distal end 80 located at the opposite end of the aerosol-generating article 10 to the mouth end 70.

(6) In use air is drawn through the aerosol-generating article by a user from the distal end 80 to the mouth end 70. The distal end 80 of the aerosol-generating article may also be described as the upstream end of the aerosol-generating article 10 and the mouth end 70 of the aerosol-generating article 10 may also be described as the downstream end of the aerosol-generating article 10. Elements of the aerosol-generating article 10 located between the mouth end 70 and the distal end 80 can be described as being upstream of the mouth end 70 or, alternatively, downstream of the distal end 80.

(7) The aerosol-forming substrate 20 is located at the extreme distal or upstream end of the aerosol-generating article 10. In the embodiment illustrated in FIG. 1, aerosol-forming substrate 20 comprises a gathered sheet of crimped homogenised tobacco material circumscribed by a wrapper. The crimped sheet of homogenised tobacco material comprises glycerin as an aerosol former. The aerosol-forming substrate 20 also comprises at least 0.05 percent by weight of a sulphide scavenger compound, based on the total dry weight of the aerosol-forming substrate 20. Suitable sulphide scavenger compounds are provided in Table 2 below.

(8) The support element 30 is located immediately downstream of the aerosol-forming substrate 20 and abuts the aerosol-forming substrate 20. In the embodiment shown in FIG. 1, the support element is a hollow cellulose acetate tube. The support element 30 locates the aerosol-forming substrate 20 at the extreme distal end 80 of the aerosol-generating article 10 so that it can be penetrated by a heating element of an aerosol-generating device. As described further below, the support element 30 acts to prevent the aerosol-forming substrate 20 from being forced downstream within the aerosol-generating article 10 towards the aerosol-cooling element 40 when a heating element of an aerosol-generating device is inserted into the aerosol-forming substrate 20. The support element 30 also acts as a spacer to space the aerosol-cooling element 40 of the aerosol-generating article 10 from the aerosol-forming substrate 20.

(9) The aerosol-cooling element 40 is located immediately downstream of the support element 30 and abuts the support element 30. In use, volatile substances released from the aerosol-forming substrate 20 pass along the aerosol-cooling element 40 towards the mouth end 70 of the aerosol-generating article 10. The volatile substances may cool within the aerosol-cooling element 40 to form an aerosol that is inhaled by the user. In the embodiment illustrated in FIG. 1, the aerosol-cooling element comprises a crimped and gathered sheet of polylactic acid circumscribed by a wrapper 90. The crimped and gathered sheet of polylactic acid defines a plurality of longitudinal channels that extend along the length of the aerosol-cooling element 40.

(10) The mouthpiece 50 is located immediately downstream of the aerosol-cooling element 40 and abuts the aerosol-cooling element 40. In the embodiment illustrated in FIG. 1, the mouthpiece 50 comprises a conventional cellulose acetate tow filter of low filtration efficiency.

(11) To assemble the aerosol-generating article 10, the four elements described above are aligned and tightly wrapped within the outer wrapper 60. In the embodiment illustrated in FIG. 1, the outer wrapper 60 is a conventional cigarette paper. As shown in FIG. 1, an optional row of perforations is provided in a region of the outer wrapper 60 circumscribing the support element 30 of the aerosol-generating article 10. A distal end portion of the outer wrapper 60 of the aerosol-generating article 10 is circumscribed by a band of tipping paper (not shown).

(12) The aerosol-generating article 10 illustrated in FIG. 1 is designed to engage with an aerosol-generating device comprising a heating element in order to be consumed by a user. In use, the heating element of the aerosol-generating device heats the aerosol-forming substrate 20 of the aerosol-generating article 10 to a sufficient temperature to form an aerosol, which is drawn downstream through the aerosol-generating article 10 and inhaled by the user.

(13) During the pre-heating phase, the sulphide scavenger compound in the aerosol-forming substrate acts to reduce the level of hydrogen sulphide emitted from the tobacco in the aerosol-forming substrate. In a pre-heating test as defined above, the reduction achieved is at least 30 percent compared to an aerosol-generating article of a similar construction but with a conventional aerosol-forming substrate not including the sulphide scavenger compound. For many sulphide scavenger compounds, a reduction of up to 70 percent in the level of hydrogen sulphide can be achieved. Such a reduction in the level of hydrogen sulphide means that the malodour from the hydrogen sulphide is minimised and may not be detectable by the consumer at all.

(14) FIG. 2 illustrates a portion of an aerosol-generating system 100 comprising an aerosol-generating device 110 and an aerosol-generating article 10 according to the embodiment described above and illustrated in FIG. 1.

(15) The aerosol-generating device 110 comprises a heating element 120. As shown in FIG. 2, the heating element 120 is mounted within an aerosol-generating article receiving chamber of the aerosol-generating device 110. In use, the user inserts the aerosol-generating article 10 into the aerosol-generating article receiving chamber of the aerosol-generating device 110 such that the heating element 120 is directly inserted into the aerosol-forming substrate 20 of the aerosol-generating article 10 as shown in FIG. 2. In the embodiment shown in FIG. 2, the heating element 120 of the aerosol-generating device 110 is a heater blade.

(16) The aerosol-generating device 110 comprises a power supply and electronics (shown in FIG. 3) that allow the heating element 120 to be actuated. Such actuation may be manually operated or may occur automatically in response to a user drawing on an aerosol-generating article 10 inserted into the aerosol-generating article receiving chamber of the aerosol-generating device 110. A plurality of openings is provided in the aerosol-generating device to allow air to flow to the aerosol-generating article 10; the direction of air flow is illustrated by arrows in FIG. 2.

(17) The support element 40 of the aerosol-generating article 10 resists the penetration force experienced by the aerosol-generating article 10 during insertion of the heating element 120 of the aerosol-generating device 110 into the aerosol-forming substrate 20. The support element 40 of the aerosol-generating article 10 thereby resists downstream movement of the aerosol-forming substrate 20 within the aerosol-generating article 10 during insertion of the heating element 120 of the aerosol-generating device 110 into the aerosol-forming substrate 20.

(18) Once the internal heating element 120 is inserted into the aerosol-forming substrate 20 of the aerosol-generating article 10 and the heating element 120 is actuated, the aerosol-forming substrate 20 of the aerosol-generating article 10 is heated to a temperature of approximately 375 degrees Celsius by the heating element 120 of the aerosol-generating device 110. At this temperature, volatile compounds are evolved from the aerosol-forming substrate 20 of the aerosol-generating article 10. As a user draws on the mouth end 70 of the aerosol-generating article 10, the volatile compounds evolved from the aerosol-forming substrate 20 are drawn downstream through the aerosol-generating article 10 and condense to form an aerosol that is drawn through the mouthpiece 50 of the aerosol-generating article 10 into the user's mouth.

(19) As the aerosol passes downstream thorough the aerosol-cooling element 40, the temperature of the aerosol is reduced due to transfer of thermal energy from the aerosol to the aerosol-cooling element 40. When the aerosol enters the aerosol-cooling element 40, its temperature is approximately 60 degrees Celsius. Due to cooling within the aerosol-cooling element 40, the temperature of the aerosol as it exits the aerosol-cooling element is approximately 40 degrees Celsius.

(20) In FIG. 3, the components of the aerosol-generating device 110 are shown in a simplified manner. Particularly, the components of the aerosol-generating device 110 are not drawn to scale in FIG. 3. Components that are not relevant for the understanding of the embodiment have been omitted to simplify FIG. 3.

(21) As shown in FIG. 3, the aerosol-generating device 110 comprises a housing 130. The heating element 120 is mounted within an aerosol-generating article receiving chamber within the housing 130. The aerosol-generating article 10 (shown by dashed lines in FIG. 3) is inserted into the aerosol-generating article receiving chamber within the housing 130 of the aerosol-generating device 110 such that the heating element 120 is directly inserted into the aerosol-forming substrate 20 of the aerosol-generating article 10.

(22) Within the housing 130 there is an electrical energy supply 140, for example a rechargeable lithium ion battery. A controller 150 is connected to the heating element 120, the electrical energy supply 140, and a user interface 160, for example a button or display. The controller 150 controls the power supplied to the heating element 120 in order to regulate its temperature.

EXAMPLES

(23) For each of the sulphide scavenger compounds indicated in Table 2 below, the sulphide scavenger compound was incorporated into a tobacco slurry having the composition shown in FIG. 1, at the concentration indicated. A tobacco sheet was formed from the tobacco slurry and the tobacco sheet was formed into an aerosol-forming substrate, using conventional techniques. An aerosol-generating article as described above with reference to FIG. 1 was then assembled. Each aerosol-generating article was subjected to the pre-heating test defined above.

(24) The percentage reductions in hydrogen sulphide and methanethiol were measured relative to a control sample in which no sulphide scavenger compound was added to the aerosol-forming substrate.

(25) It can be seen from the results below that for each compound, a reduction of over 50 percent of hydrogen sulphide was observed relative to the control sample. In many cases, a reduction of over 70 percent was observed. Significant reductions in methanethiol were also observed.

(26) TABLE-US-00001 TABLE 1 Slurry component % by weight in slurry Tobacco powder 21 Guar gum 0.75 Cellulosic fibres 0.5 Glycerin 5 Water 72.75

(27) TABLE-US-00002 TABLE 2 Amount of metal component % Reduction % Reduction Sulphide scavenger (% based on dry in Hydrogen in compound weight of substrate) Sulphide Methanethiol Zinc sulphate 1.3 79 38 Zinc carbonate basic 2.3 86 45 Iron (II) sulphate 2.0 63 48 Iron (III) sulphate 2.0 58 50 Copper (II) sulphate 0.81 100 96 Copper (II) sulphate 0.202 100 52 Copper (II) sulphate 0.051 89 40