A FORMULATION FOR USE IN AN AEROSOL-GENERATING SYSTEM

Abstract

A formulation for an aerosol-generating system is provided, the formulation including: one or more aerosol formers; one or more metal salts; and one or more polymeric thickening agents, in which the formulation has a polymeric thickening agent content of greater than or equal to about 0.5 percent by weight, and in which the one or more metal salts include one or more metal stearates. An aerosol-generating article for the aerosol-generating system, and an aerosol-generating system, are also provided.

Claims

1.-14. (canceled)

15. A formulation for an aerosol-generating system, the formulation comprising: one or more aerosol formers; one or more metal salts; and one or more polymeric thickening agents, wherein the formulation has a polymeric thickening agent content of greater than or equal to about 0.5 percent by weight, and wherein the one or more metal salts include one or more metal stearates.

16. The formulation according to claim 15, wherein the formulation has a polymeric thickening agent content of between about 5 percent by weight and about 20 percent by weight.

17. The formulation according to claim 15, wherein the one or more polymeric thickening agents are selected from the group consisting of: polyvinyl alcohol, polyethylene glycol, polypropylene glycol, and starch.

18. The formulation according to claim 15, wherein the one or more metal salts are selected from the group consisting of: metal alginates, metal benzoates, metal cinnamates, metal cycloheptanecarboxylates, metal levulinates, metal propanoates, metal stearates, and metal undecanoates.

19. The formulation according to claim 18, wherein the one or more metal salts are selected from the group consisting of metal cinnamates, metal cycloheptanecarboxylates, metal stearates, and metal undecanoates.

20. The formulation according to claim 15, wherein the formulation has a metal stearate content of greater than or equal to about 0.5 percent.

21. The formulation according to claim 15, wherein the one or more metal stearates comprise sodium stearate.

22. The formulation according to claim 15, wherein the one or more aerosol formers comprise glycerine.

23. The formulation according to claim 22, wherein the one or more aerosol formers comprise glycerine and propylene glycol.

24. The formulation according to claim 23, wherein a ratio of the weight percent glycerine content to the weight percent propylene glycol content of the formulation is greater than or equal to about 1.5.

25. The formulation according to claim 15, wherein the formulation has an aerosol former content of greater than or equal to about 50 percent by weight.

26. The formulation according to claim 15, further comprising water.

27. The formulation according to claim 26, wherein the formulation has a water content of less than or equal to about 30 percent by weight.

28. An aerosol-generating article for an aerosol-generating system, the aerosol-generating article containing a formulation according to claim 15.

29. An aerosol-generating system, comprising: a formulation according to claim 15; and an atomiser configured to generate an aerosol from the formulation.

Description

[0126] Specific embodiments will now be described, by way of example only, with reference to the following examples and the accompanying drawings, in which:

[0127] FIG. 1 shows schematically a sectional side view of an aerosol-generating system comprising an aerosol-generating device and an aerosol-generating article comprising a formulation according to the invention;

[0128] FIG. 2 shows schematically a sectional view of the aerosol-generating system of FIG. 1, with the aerosol-generating article inserted into the aerosol-generating device;

[0129] FIG. 3 shows schematically a sectional view of an alternative aerosol-generating system comprising an aerosol-generating device and an aerosol-generating article comprising a formulation according to the invention;

[0130] FIG. 4 shows schematically a sectional view of an aerosol-generating article comprising a formulation according to the invention;

[0131] FIG. 5 shows schematically a sectional view of an aerosol-generating article comprising a formulation according to the invention

[0132] FIG. 6 is a graph showing average aerosolised collected mass in mg per puff for a range of different aerosol former compositions;

[0133] FIG. 7 is a graph showing average nicotine in mg per puff for a range of different aerosol former compositions; and

[0134] FIG. 8 is a graph showing average nicotine percent for a range of different aerosol former compositions.

[0135] Aerosol-generating systems for delivering to a user typically comprise an atomiser configured to generate an inhalable aerosol from a formulation. Some known aerosol-generating systems comprise a thermal atomiser such as an electric heater that is configured to heat and vaporise the formulation to generate an aerosol. Typical formulations for use in aerosol-generating systems are nicotine formulations, which may be liquid nicotine formulations comprising an aerosol former such as glycerine and/or propylene glycol.

[0136] An aerosol generating system can comprise an aerosol-generating device and an aerosol-generating article containing a formulation. Typical aerosol-generating systems may suffer from a problem of unwanted leakage of the formulation out of the aerosol-generating article. Leakage of a formulation may occur in a number of different situations, such as: when there is too much of the formulation in a reservoir of the aerosol-generating article; when the material forming one or more parts of the aerosol-generating article or system fails to retain the formulation as designed; due to a change in pressure, for example when at a high altitude during transport by an aeroplane; or at a high temperature, for example due to hot weather.

[0137] It would be desirable to provide a formulation that provides a reduced risk of leakage from an aerosol-generating article or system compared to typical formulations.

[0138] FIGS. 1 and 2 show an aerosol-generating system including an aerosol-generating device 10 and an aerosol-generating article 20. In this example, the aerosol-generating article 20 is cartridge.

[0139] The aerosol-generating device 10 is configured to receive the aerosol-generating article 20 in a cavity 18. The aerosol-generating article 20 includes a housing 24. The housing 24 defines a reservoir 22. The reservoir 22 has a reservoir opening that can be covered by a removable cover 26. An aerosol-forming substrate is disposed in the reservoir 22. The aerosol-forming substrate in the reservoir 22 may be a formulation according to the invention.

[0140] In the example shown in FIGS. 1 and 2, the aerosol-generating article 20 includes an atomiser configured to generate an aerosol from the formulation in the reservoir 22. The atomiser may be a thermal atomiser. In the example shown in FIGS. 1 and 2 the atomiser is an electric heater 30.

[0141] In the example of FIGS. 1 and 2, the aerosol-generating article 20 contains an aerosol-forming substrate and an atomiser and may therefore be referred to as a “cartomiser”.

[0142] The aerosol-generating article 20 is replaceable by a user when the aerosol-forming substrate provided in the reservoir 22 is depleted.

[0143] FIG. 1 shows the aerosol-generating article 20 just prior to insertion into the aerosol-generating device 10. The arrow 1 in FIG. 1 indicates the direction of insertion of the aerosol-generating article 20 in to the aerosol-generating device 10.

[0144] The aerosol-generating device 10 is portable and has a size comparable to a conventional cigar or cigarette. The aerosol-generating device 10 comprises a main body 11 and a mouthpiece portion 12. The main body 11 contains a battery 14, such as a lithium iron phosphate battery, control electronics 16 and a cavity 18.

[0145] The mouthpiece portion 12 is connected to the main body 11 by a hinged connection 21 and can move between an open position as shown in FIG. 1 and a closed position as shown in FIG. 2. The mouthpiece portion 12 is placed in the open position to allow for insertion and removal of an aerosol-generating article 20 and is placed in the closed position when the aerosol-generating system is to be used to generate aerosol.

[0146] The mouthpiece portion 12 comprises a plurality of air inlets 13 and an outlet 15. In use, a user sucks or puffs on the outlet 15 to draw air from the air inlets 13, through the mouthpiece portion to the outlet 15, and thereafter into the mouth or lungs of the user. Internal baffles 17 are provided to force the air flowing through the mouthpiece portion 12 past the aerosol-generating article 20.

[0147] The housing 24 includes a capillary material soaked in the aerosol-forming substrate. The capillary material in this example is positioned adjacent the electric heater 30.

[0148] The cavity 18 has a circular cross-section and is sized to receive a housing 24 of the aerosol-generating article 20. Electrical connectors 19 are provided at the sides of the cavity 18 to provide an electrical connection between the control electronics 16 and battery 14 and corresponding electrical contacts on the aerosol-generating article 20. This setup allows power to be supplied to the electric heater 30.

[0149] FIG. 2 shows the aerosol-generating article 20 inserted into the cavity 18 of the aerosol-generating device 10. In this position, the electrical connectors 19 rest against the corresponding electrical contacts on the aerosol-generating article 20. The cover 26 has been fully removed and the mouthpiece portion 12 has been moved to a closed position.

[0150] The mouthpiece portion 12 is retained in the closed position by a clasp mechanism (not illustrated). It will be apparent to a person of ordinary skill in the art that other suitable mechanisms for retaining the mouthpiece in a closed position may be used, such as a snap fitting or a magnetic closure.

[0151] The mouthpiece portion 12 in a closed position retains the aerosol-generating article 20 in electrical contact with the electrical connectors 19 so that a good electrical connection is maintained in use, whatever the orientation of the aerosol-generating system is.

[0152] In use, when the aerosol-generating device 10 is activated by a user, the electric heater 30 aerosolises at least a portion of the aerosol-forming substrate in the reservoir 22. As a user sucks or puffs on the outlet 15, air flows through the air inlets 13 and over the electric heater 30 and the capillary material. The air flowing over the electric heater 30 and the capillary material entrains the volatized aerosol components from the vaporised aerosol-forming substrate. The air with entrained aerosol-forming substrate then flows out through the outlet 15 and to the user. This air flow regime is shown in FIG. 2.

[0153] FIG. 3 shows an alternative embodiment of an aerosol-generating system. The embodiment shown in FIG. 3 works in much the same way as the embodiment shown in FIGS. 1 and 2. However, in the embodiment of FIG. 3, the aerosol-generating article 20 is not removable from the aerosol-generating device 10. Instead, after the reservoir 22 has been depleted of aerosol-generating substrate, the reservoir 22 can be refilled by a user through a reservoir opening 40.

[0154] In FIG. 3 the reservoir opening 40 is shown in an open position in which it can be refilled with aerosol-generating substrate. The reservoir opening 40 can however be sealed with a closure such as a cap (not shown).

[0155] The embodiment shown in FIG. 3 otherwise works in a similar way to the embodiment shown in FIGS. 1 and 2.

[0156] FIGS. 4 and 5 are schematic sectional views of an alternative aerosol-generating article 200. FIG. 4 shows the aerosol-generating article 200 before it has been used by the user. The aerosol-generating article 200 includes a body 212 defining a reservoir 210 having a reservoir opening 215. Aerosol-forming substrate 211 is disposed in the reservoir 210. The aerosol-generating article 200 includes a heater 222 located across the reservoir opening 215. In this example, the heater 222 has a heating element in the form of a mesh layer 223. The aerosol-generating article 200 also includes a transfer element 224. The transfer element 224 is preferably formed from a porous material. In the example of FIG. 4, the transfer element 224 is formed from a layer of glass fibers. The transfer element 224 provides control of the flow of the aerosol-forming substrate 211 from the reservoir 210 to the mesh layer 213 of the heater 222. In this example, the aerosol-forming substrate 211 is a formulation according to the invention.

[0157] In use, the formulation flows from the reservoir 210 and into the porous transfer element 224. The formulation then flows to the mesh layer 223 of the heater 222, where it is thermally vaporised into an aerosol.

[0158] It may be advantageous to mix the aerosol-forming substrate 211 before or during heating of the aerosol-forming substrate 211 by the heater 222. Mixing the aerosol-forming substrate 211 ensures that the aerosol-forming substrate 211 becomes or remains as a substantially homogeneous mixture. In the example shown in FIG. 4, the aerosol-generating article 200 includes a mixer that is operable to stir the aerosol-forming substrate 211. The mixer may be mechanically operated or electrically operated. In this example, the mixer is an agitator 226. The agitator 226 may be a linear resonant actuator. In other examples, the mixer may be a different type of device or mechanism that is suitable for mixing liquids, such as a magnetic stirrer. In another example, the aerosol-forming substrate 211 may be mechanically mixed by the user. In another example, the aerosol-forming substrate 211 may be mixed during the manufacturing process, for example by ultrasonic vibration.

EXAMPLES

[0159] Three formulations according to the invention (Examples A, B and C) are prepared having the compositions shown in Table 1. The formulations of Examples A, B and C are liquid at standard temperature and pressure.

TABLE-US-00002 TABLE 2 Example A B C Glycerine (% by weight) aerosol former 91 84 81 Sodium Stearate (% by weight) metal salt 2 2 2 Polyvinyl Alcohol (% by weight) Polymeric thickening agent 7 8 7 Water (% by weight) 0 6 10

[0160] The formulations A, B and C are prepared by mixing the components together in, for example, a vessel. The aerosol former, which in these examples is glycerine, is added into the vessel first. Next, the metal salt, which in these examples is sodium stearate, is added into the vessel. Water is then added into the vessel. Finally, the polymeric thickening agent, which in this case is polyvinyl alcohol, is added into the vessel. The components are then mixed together in the vessel.

[0161] The formulations of Examples A and B are then heated on a hot plate for a period of time. In this example, the formulations of Examples A and B are heated for six minutes. Samples of the formulations of Examples A and B are heated to different temperatures. In one example, a sample of the formulations of Examples A and B is heated to 200 degrees Celsius. In another example, the formulations of Examples A and B is heated to 120 degrees Celsius. In another example, the formulations of Examples A and B is heated to 90 degrees Celsius. The formulations of Examples A and B are then removed from the hot plate.

[0162] After cooling down, some of the six samples solidify. Examples A and B that are heated to 200 degrees Celsius both solidify. Examples A and B that are heated to 120 degrees Celsius also both solidify. The Example A that is heated to 90 degrees Celsius does not solidify and remains as a liquid. However, the Example B that is heated to 90 degrees does solidify.

[0163] An example of use of a formulation according to the invention as an aerosol-forming substrate will now be described with reference to the formulation of Example C when used as an aerosol-forming substrate 211 in the aerosol-generating article 200 shown in FIGS. 4 and 5.

[0164] Advantageously, as an initial step, the agitator 226 can be activated for a period of time in order to mix the aerosol-forming substrate. In another example, the aerosol-generating article 200 may be shaken by a user in order to mix the aerosol-forming substrate 211. The initial step of mixing ensures that the aerosol-forming substrate 211 is a substantially homogenous mixture prior to heating.

[0165] The aerosol-generating article 200 is then inserted into the aerosol-generating device 10 that is shown in FIG. 1.

[0166] The aerosol-generating device is then activated by a user. Activation of the aerosol-generating device involves activation of the heater 222 of the aerosol-generating article 200. Activation of the heater 222 heats a portion of the aerosol-generating substrate 211 contained within the transfer element 224. Heating of aerosol-forming substrate 211 contained within the transfer element 224 vaporises at least a portion of the aerosol-generating substrate 211 into an aerosol. In this example, the heater 222 is activated at a power of 0.8 Watts for a time of six minutes. In one example, the heater 222 may be activated at a different power level. In another example, the heater 222 may be activated for a different time period.

[0167] Activation of the heater 222 at a power of 0.8 Watts for six minutes increases the temperature of the mesh layer 223 to around 200 degrees Celsius.

[0168] When the mesh layer 223 of the heater 222 cools, the aerosol-forming substrate 211 that was heated but not evaporated solidifies into a solid layer 225. The solid layer 225 may be held within the transfer element 224. In this example, the solid layer 225 that is formed completely covers the reservoir opening 215.

[0169] FIG. 5 shows the aerosol-generating article 200 after a first use by a user. That is, FIG. 5 shows the aerosol-generating article 200 after a first heating cycle of six minutes has occurred.

[0170] As can be seen from FIG. 5, after the first use of the aerosol-generating article 200, a solid layer 225 has been formed partially within the transfer element 224. The solid layer 225 is also in contact with the mesh layer 223 of the heater 222. In the example shown in FIG. 5, the solid layer 225 internally seals the reservoir opening 215. Advantageously, sealing the reservoir opening 215 may prevent the formulation (that is, the aerosol-forming substrate) from escaping from the reservoir 210.

[0171] The aerosol-generating article 200 may be used several times before the aerosol-generating substrate 211 contained within the reservoir 210 is fully consumed. Thus, the aerosol-generating article 200 may experience multiple heating cycles.

[0172] Before a second heating cycle, the solid layer 225 remains in position blocking the porous mesh layer 223 (as is shown in FIG. 5) and preventing escape of the formulation out of the reservoir opening 215. When the aerosol-generating article 200 is used for a second time, the heater 222 is activated for a second heating cycle. Activating the heater 222 for a second heating cycle 222 heats the mesh layer 223. Heating the mesh layer 223 increases the temperature of the solid layer 225 that is formed on the mesh layer 223 until the solid layer 225 melts into a liquid. At this point, in some examples, the aerosol-forming substrate may be fully liquid. As the temperature of the aerosol-forming substrate 211 increases, a portion of the aerosol-forming substrate 211 is vaporised by the heater 222.

[0173] After the second heating cycle has finished, as the mesh layer 223 of the heater 222 cools, the aerosol-forming substrate 211 that was heated but not evaporated solidifies within the transfer element 224 into another solid layer 225. In this example, the solid layer 225 again covers the mesh layer 223 and therefore again seals the reservoir opening 215, thereby preventing aerosol-forming substrate 211 from leaking out of the reservoir 210.

[0174] In an alternative example, the first heating cycle is activated during manufacturing. For example, the first heating cycle may be activated after the reservoir 210 has been filled with the aerosol-forming substrate 211.

[0175] In one example, a further step is carried out. This further step is optional and not necessary to provide the advantages and effects of the invention. After a heating cycle has been activated and the solid layer 225 begins to form as the aerosol-forming substrate 211 cools, the aerosol-generating article 200 is rotated into a particular orientation that promotes formation of the solid layer 225 in a position that blocks the mesh layer 223, thereby sealing the reservoir opening 215 closed. For example, the aerosol-generating article 200 may be stored upside down after the first heating cycle.

[0176] Advantageously, the solid layer 225 formed after the formulation cools down provides a barrier that seals the reservoir opening 215 closed. Sealing the reservoir 215 prevents fluid from escaping out of the reservoir 215. Accordingly, the solid layer 225 prevents the formulation from leaking out of the reservoir 215 between uses of the aerosol-generating device 600. A reservoir seal may be advantageous in certain circumstances that typically result in leakage of formulation out of the reservoir 215, such as due to changes in pressure (for example when a user is climbing a mountain or travelling in an aeroplane) and at high temperatures (for example due to strong summer heat).

[0177] FIG. 6 shows the average aerosolised collected mass in mg per puff for a range of different aerosol former compositions when the weight percent of propylene glycol (PG) is varied relative to the weight percent of vegetable glycerine (VG). For example, the data for “25% PGvsVG” is for a formulation comprising an aerosol former composition that contains 25 percent by weight propylene glycol and 75 percent by weight vegetable glycerine.

[0178] FIG. 7 is a graph showing average nicotine in mg per puff for a range of different aerosol former compositions when the weight percent of propylene glycol (PG) is varied relative to the weight percent of vegetable glycerine (VG). For example, the data for “25% PGvsVG” is for a formulation comprising an aerosol former composition that contains 25 percent by weight propylene glycol and 75 percent by weight vegetable glycerine.

[0179] FIG. 8 is a graph showing average nicotine percent for a range of different aerosol former compositions when the weight percent of propylene glycol (PG) is varied relative to the weight percent of vegetable glycerine (VG). For example, the data for “25% PGvsVG” is for a formulation comprising an aerosol former composition that contains 25 percent by weight propylene glycol and 75 percent by weight vegetable glycerine.

[0180] The data in the graphs shows that, as discussed above, by including propylene glycol as an aerosol former in a formulation that includes nicotine, there is an improvement in the nicotine content of the aerosol. For example, the highest weight percent of nicotine is when there is 5 weight percent of propylene glycol in the aerosol former. This improvement may be due to more efficient vaporisation of the nicotine because propylene glycol has a lower boiling point (188° C.) compared to glycerine (290° C.).

[0181] However, if there is high amount of propylene glycol in the formulation (for example 25 percent by weight propylene glycol) then the nicotine content of the aerosol decreases because the propylene glycol can be vaporised during a heating cycle. Therefore, it is advantageous to have a limited amount of propylene glycol in the nicotine formulation.

[0182] The exemplary embodiments described above are not intended to limit the scope of the claims. Other embodiments consistent with the exemplary embodiments described above will be apparent to those skilled in the art. Features described in relation to one embodiment may also be applicable to other embodiments.