Aerosol-generating article comprising an aerosol-forming substrate and a heat-conducting element

Abstract

An aerosol-generating article is provided, including an aerosol-forming substrate including aerosol-forming material and a tobacco-containing wrapper around and in contact with the aerosol-forming material, the wrapper having an aerosol former content of between about 5% and about 30% by weight of the total weight of the wrapper; a combustible heat source upstream of the aerosol-forming substrate; and a heat-conducting element around and in contact with at least a portion of the wrapper.

Claims

1. An aerosol-generating article, comprising: an aerosol-forming substrate comprising aerosol-forming material and a tobacco-containing wrapper around and in contact with the aerosol-forming material, the wrapper having an aerosol former content of between about 5% and about 30% by weight of the total weight of the wrapper; a combustible heat source upstream of the aerosol-forming substrate; and a heat-conducting element around and in contact with at least a portion of the wrapper.

2. The aerosol-generating article according to claim 1, wherein the heat-conducting element is around and in contact with at least a rear portion of the combustible heat source and at least a front portion of the wrapper.

3. The aerosol-generating article according to claim 1, further comprising a non-combustible substantially air-impermeable barrier between a rear end face of the combustible heat source and the aerosol-forming substrate.

4. The aerosol-generating article according to claim 1, wherein the combustible heat source is a blind combustible carbonaceous heat source.

5. The aerosol-generating article according to claim 1, wherein the wrapper has an aerosol former content of at least about 10% by weight of a total weight of the wrapper.

6. The aerosol-generating article according to claim 1, wherein the wrapper has an aerosol former content of less than or equal to about 20% by weight of a total weight of the wrapper.

7. The aerosol-generating article according to claim 1, wherein the aerosol former comprises one or more polyhydric alcohols.

8. The aerosol-generating article according to claim 7, wherein the aerosol former comprises glycerine.

9. The aerosol-generating article according to claim 1, wherein the heat-conducting element comprises one or both of a metal foil and a metal alloy foil.

10. The aerosol-generating article according to claim 9, wherein the heat-conducting element comprises aluminum foil.

11. The aerosol-generating article according to claim 1, wherein the aerosol-forming substrate comprises tobacco material.

12. An aerosol-generating article, comprising: an aerosol-forming substrate comprising aerosol-forming material and a wrapper around and in contact with the aerosol-forming material, the wrapper having an aerosol former content of between about 5% and about 30% by weight of the total weight of the wrapper; and a heat-conducting element around and in contact with at least a portion of the wrapper, wherein the heat-conducting element is a susceptor.

13. The aerosol-generating article according to claim 12, wherein the wrapper is a tobacco-containing wrapper.

14. An aerosol-generating system, comprising: an aerosol-generating article according to claim 12; and an electrically-operated aerosol-generating device comprising an inductor configured to produce a fluctuating or alternating electromagnetic field.

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 schematic longitudinal cross-section of an aerosol-generating article according to an embodiment of the invention; and

(3) FIG. 2 shows a graph of (a) the amounts of aerosol former (glycerine) and (b) the amounts of nicotine delivered per puff for an aerosol-generating article according to the embodiment of the invention shown in FIG. 1 and two aerosol-generating articles not according to the invention.

(4) The aerosol-generating article 2 according to the embodiment of the invention shown in FIG. 1 comprises a combustible carbonaceous heat source 4 having a front end face 6 and an opposed rear end face 8, an aerosol-forming substrate 10, a transfer element 12, an aerosol-cooling element 14, a spacer element 16 and a mouthpiece 18 in abutting coaxial alignment. As shown in FIG. 1, the aerosol-forming substrate 10, transfer element 12, aerosol-cooling element 14, spacer element 16 and mouthpiece 18 and a rear portion of the blind combustible heat source 4 are wrapped in an outer wrapper 20 of sheet material such as, for example, cigarette paper.

(5) The combustible carbonaceous heat source 4 is a blind carbonaceous combustible heat source and is located at the distal end of the aerosol-generating article 2. As shown in FIG. 1, a non-combustible substantially air impermeable barrier 22 in the form of a disc of aluminium foil is provided between the rear end face 8 of the combustible carbonaceous heat source 4 and the aerosol-forming substrate 10. The barrier 22 is applied to the rear end face 8 of the combustible carbonaceous heat source 4 by pressing the disc of aluminium foil onto the rear end face 8 of the combustible carbonaceous heat source 4 and abuts the rear end face 8 of the combustible carbonaceous heat source 4 and the aerosol-forming substrate 10.

(6) The aerosol-forming substrate 10 is located immediately downstream of the barrier 22 applied to the rear end face 8 of the combustible carbonaceous heat source 4. The aerosol-forming substrate 10 comprises a gathered crimped sheet of homogenised tobacco material 24 and a wrapper 26 around and in direct contact with the gathered crimped sheet of homogenised tobacco material 24. The gathered crimped sheet of homogenised tobacco material 24 comprises a suitable aerosol former such as, for example, glycerine. The wrapper 26 comprises a suitable aerosol former such as, for example, glycerine, and has an aerosol former content of between about 8% and about 20% by weight of the total weight of the wrapper.

(7) The transfer element 12 is located immediately downstream of the aerosol-forming substrate 10 and comprises a cylindrical open-ended hollow cellulose acetate tube 28.

(8) The aerosol-cooling element 14 is located immediately downstream of the transfer element 12 and comprises a gathered sheet of biodegradable polymeric material such as, for example, polylactic acid.

(9) The spacer element 16 is located immediately downstream of the aerosol-cooling element 14 and comprises a cylindrical open-ended hollow paper or cardboard tube.

(10) The mouthpiece 18 is located immediately downstream of the spacer element 16. As shown in FIG. 1, the mouthpiece 18 is located at the proximal end of the aerosol-generating article 2 and comprises a cylindrical plug of suitable filtration material 30 such as, for example, cellulose acetate tow of very low filtration efficiency, wrapped in filter plug wrap 32.

(11) The aerosol-generating article may further comprise a band of tipping paper (not shown) circumscribing a downstream end portion of the outer wrapper 20.

(12) As shown in FIG. 1, the aerosol-generating article 2 further comprises a heat-conducting element 34 formed from a suitable thermally conductive material such as, for example, aluminium foil around and in direct contact with a rear portion 4b of the blind combustible heat source 4 and a front portion 10a of the aerosol-forming substrate 10. In the aerosol-generating article 2 according to the first embodiment of the invention shown in FIG. 1, the aerosol-forming substrate 10 extends downstream beyond the heat-conducting element 34. That is, the heat-conducting element 34 is not around and in direct contact with a rear portion of the aerosol-forming substrate 10. However, it will be appreciated that in other embodiments of the invention (not shown), the heat-conducting element 34 may be around and in contact with the entire length of the aerosol-forming substrate 10. It will also be appreciated that in other embodiments of the invention (not shown), one or more additional heat-conducting elements may be provided that overlie the heat-conducting element 34.

(13) The aerosol-generating article 2 according to the embodiment of the invention shown in FIG. 1 comprises one or more first air inlets 36 around the periphery of the aerosol-forming substrate 10. As shown in FIG. 1, a circumferential arrangement of first air inlets 36 is provided in the wrapper 26 of the aerosol-forming substrate 10 and the overlying outer wrapper 20 to admit cool air (shown by dotted arrows in FIG. 1) into the aerosol-forming substrate 10.

(14) In use, a user ignites the combustible carbonaceous heat source 4. Once the combustible carbonaceous heat source 4 is ignited the user draws on the mouthpiece 18 of the aerosol-generating article 2. When a user draws on the mouthpiece 18, cool air (shown by dotted arrows in FIG. 1) is drawn into the aerosol-forming substrate 10 of the aerosol-generating article 2 through the first air inlets 36.

(15) The periphery of the front portion 10a of the aerosol-forming substrate 10 is heated by conduction through the rear end face 8 of the combustible carbonaceous heat source 4 and the barrier 22 and through the heat-conducting element 34.

(16) The heating of the aerosol-forming substrate 10 by conduction releases aerosol former from the wrapper 26 and releases aerosol former and other volatile and semi-volatile compounds from the gathered crimped sheet of homogenised tobacco material 24. The compounds released from the aerosol-forming substrate 10 form an aerosol that is entrained in the air drawn into the aerosol-forming substrate 10 of the aerosol-generating article 2 through the first air inlets 36 as it flows through the aerosol-forming substrate 10. The drawn air and entrained aerosol (shown by dashed arrows in FIG. 1) pass downstream through the interior of the cylindrical open-ended hollow cellulose acetate tube 28 of the transfer element 12, the aerosol-cooling element 14 and the spacer element 16, where they cool and condense. The cooled drawn air and entrained aerosol pass downstream through the mouthpiece 18 and are delivered to the user through the proximal end of the aerosol-generating article 2. The non-combustible substantially air impermeable barrier 22 on the rear end face 8 of the combustible carbonaceous heat source 4 isolates the combustible carbonaceous heat source 4 from air drawn through the aerosol-generating article 2 such that, in use, air drawn through the aerosol-generating article 2 does not come into direct contact with the combustible carbonaceous heat source 4.

(17) An aerosol-generating article according to the embodiment of the invention shown in FIG. 1 is produced comprising: an aerosol-forming substrate comprising a gathered crimped sheet of homogenised tobacco material comprising glycerine and a tobacco-containing paper wrapper around and in direct contact with the gathered crimped sheet of homogenised tobacco material, the tobacco-containing paper wrapper having a glycerine content of 10% by weight of the total weight of the tobacco-containing paper wrapper; and a heat-conducting element formed of aluminium foil around and in contact with a front portion of the tobacco-containing paper wrapper.

(18) A first comparative aerosol-generating article not according to the invention is produced comprising: an aerosol-forming substrate comprising a gathered crimped sheet of homogenised tobacco material comprising glycerine and a tobacco-containing paper wrapper around and in direct contact with the gathered crimped sheet of homogenised tobacco material; and a heat-conducting element formed of aluminium foil around and in contact with a front portion of the tobacco-containing paper wrapper. The tobacco-containing paper wrapper in the first comparative aerosol-generating article not according to the invention does not comprise glycerine. Otherwise, the tobacco-containing paper wrapper in the first comparative aerosol-generating article not according to the invention is the same as the tobacco-containing paper wrapper in the aerosol-generating article according to the invention.

(19) A second aerosol-generating article not according to the invention is also produced comprising: an aerosol-forming substrate comprising a gathered crimped sheet of homogenised tobacco material comprising glycerine and a paper wrapper of filter plug wrap around and in direct contact with the gathered crimped sheet of homogenised tobacco material; and a heat-conducting element formed of aluminium foil around and in contact with a front portion of the paper wrapper of filter plug wrap.

(20) The first comparative aerosol-generating article and the second comparative aerosol-generating article not according to the invention differ only from the aerosol-generating article according to the invention in the type of wrapper around and in direct contact with the gathered crimped sheet of homogenised tobacco material; the combustible carbonaceous heat sources, heat-conducting elements, transfer elements, aerosol-cooling elements, spacer elements and mouthpieces and all other components and dimensions of the first comparative aerosol-generating article and the second comparative aerosol-generating article are identical to those of the aerosol-generating article according to the invention.

(21) The amounts of (a) glycerine (in micrograms) and (b) nicotine (in micrograms) per puff for the aerosol-generating article according to the invention, the first comparative aerosol-generating article and the second comparative aerosol-generating article are measured as a function of puff number under a Health Canada smoking regime over 12 puffs with a puff volume of 55 ml, puff duration of 2 seconds and a puff interval of 30 seconds. Each puff is collected on a Cambridge filter pad and then extracted with a liquid solvent. The resulting liquid is analysed by gas chromatography to determine the nicotine delivery. The results are shown in: FIG. 2 (a) puff-by-puff glycerine delivery profile; and FIG. 2 (b) puff-by-puff nicotine delivery profile. In FIG. 2 (a) and FIG. 2 (b) the puff-by-puff delivery profile for the aerosol-generating article according to the invention is shown by the right hand columns, the puff-by-puff delivery profile for the first comparative aerosol-generating article is shown by the central columns and the puff-by-puff delivery profile for the second comparative aerosol-generating article is shown by the left-hand columns.

(22) As illustrated FIG. 2 (a) and 2 (b), the inclusion of a wrapper having an aerosol former content of 10% by weight of the total weight of the wrapper around and in direct contact with the tobacco material of the aerosol-forming substrate of the aerosol-generating article according to the invention advantageously results in more consistent puff-by-puff glycerine and nicotine delivery profiles than are obtained for the first comparative aerosol-generating article not according to the invention and the second comparative aerosol-generating article not according to the invention, which comprise an aerosol-forming substrate comprising tobacco material and a wrapper around and in direct contact with the tobacco material wherein the wrapper does not have an aerosol former content of between about 5% and about 30% by weight of the total weight of the wrapper. As shown in FIG. 2 (a) and 2 (b), the inclusion of a wrapper having an aerosol former content of 10% by weight of the total weight of the wrapper around and in direct contact with the tobacco material of the aerosol-forming substrate of the aerosol-generating article according to the invention generally results in an increase in the amounts of nicotine and glycerine in initial puffs (puffs 1 to 3) and final puffs (puffs 9 to 12) and a decrease in the amounts of nicotine and glycerine in intermediate puffs (puffs 5 to 7) compared to the first comparative aerosol-generating article and the second comparative aerosol-generating article.

(23) The specific embodiments and examples described above illustrate but do not limit the invention. It is to be understood that other embodiments of the invention may be made and the specific embodiments and examples described herein are not exhaustive.