Aerosol-generating article with improved outermost wrapper

Abstract

An aerosol-generating article is provided, including an aerosol-forming substrate; and an outermost wrapper around at least a portion of the aerosol-forming substrate, wherein an outer surface of the outermost wrapper forms at least part of an outer surface of the aerosol-generating article, and wherein the outermost wrapper includes a metallized substrate comprising a substrate layer and a metal layer radially outward of the substrate layer, the metal layer having a thickness of less than or equal to about 100 nm.

Claims

1. An aerosol-generating article, comprising: an aerosol-forming substrate configured to be heated to generate an aerosol, wherein the aerosol-generating article does not comprise an aerosol-forming substrate that is configured to be combusted to produce smoke; and an outermost wrapper around at least a portion of the aerosol-forming substrate, wherein an outer surface of the outermost wrapper forms at least part of an outer surface of the aerosol-generating article, and wherein the outermost wrapper comprises a metallized substrate comprising a substrate layer and a metal layer radially outward of the substrate layer, the metal layer having a thickness of less than or equal to 100 nm.

2. The aerosol-generating article according to claim 1, wherein the metal layer of the metallized substrate has a thickness of greater than or equal to 5 nm.

3. The aerosol-generating article according to claim 1, wherein the metal layer of the metallized substrate has a thickness of between 10 nm and 60 nm.

4. The aerosol-generating article according to claim 1, wherein the metal layer of the metallized substrate is an aluminum layer.

5. The aerosol-generating article according to claim 1, wherein the substrate layer of the metallized substrate has a thickness of between 40 μm and 80 μm.

6. The aerosol-generating article according to claim 1, wherein the substrate layer of the metallized substrate is a paper layer.

7. The aerosol-generating article according to claim 6, wherein the paper layer of the metallized substrate has a basis weight of between 35 grams per square meter and 60 grams per square meter.

8. The aerosol-generating article according to claim 1, wherein the outermost wrapper further comprises a surface coating on at least a portion of an outer surface of the metal layer of the metallized substrate.

9. The aerosol-generating article according to claim 8, wherein the surface coating comprises one or more inorganic materials selected from the group consisting of graphite, metal oxides, and metal carbonates.

10. The aerosol-generating article according to claim 1, wherein the outer surface of the outermost wrapper has an emissivity of less than or equal to 0.6.

11. The aerosol-generating article according to claim 1, wherein the outer surface of the outermost wrapper has an emissivity of greater than or equal to 0.1.

12. The aerosol-generating article according to claim 1, further comprising a heat-conducting element radially inward of the outermost wrapper.

13. The aerosol-generating article according to claim 12, wherein the outermost wrapper is around at least a portion of the heat-conducting element.

14. The aerosol-generating article according to claim 1, further comprising a heat source.

15. The aerosol-generating article according to claim 14, wherein the heat source is a combustible heat source.

16. The aerosol-generating article according to claim 15, wherein the aerosol-forming substrate is downstream of the combustible heat source.

17. The aerosol-generating article according to claim 14, wherein the outermost wrapper is around at least a portion of the heat source.

18. An aerosol-generating article, comprising: a proximal end and a distal end; a combustible carbonaceous heat source; an aerosol-forming substrate located between the combustible carbonaceous heat source and the proximal end of the aerosol-generating article, wherein the aerosol-generating article does not comprise an aerosol-forming substrate located between the combustible carbonaceous heat source and the distal end of the aerosol-generating article; and an outermost wrapper around at least a portion of the aerosol-forming substrate, wherein an outer surface of the outermost wrapper forms at least part of an outer surface of the aerosol-generating article, and wherein the outermost wrapper comprises a metallized substrate comprising a substrate layer and a metal layer radially outward of the substrate layer, the metal layer having a thickness of less than or equal to 100 nm.

19. An aerosol-generating article, comprising: a proximal end and a distal end; a combustible carbonaceous heat source located at the distal end of the aerosol-generating article; an aerosol-forming substrate located between the combustible carbonaceous heat source and the proximal end of the aerosol-generating article; and an outermost wrapper around at least a portion of the aerosol-forming substrate, wherein an outer surface of the outermost wrapper forms at least part of an outer surface of the aerosol-generating article, and wherein the outermost wrapper comprises a metallized substrate comprising a substrate layer and a metal layer radially outward of the substrate layer, the metal layer having a thickness of less than or equal to 100 nm.

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 the amounts of aerosol former (glycerine) per puff for an example of the aerosol-generating article according to the embodiment shown in FIG. 1 and a comparative example of an aerosol-generating article 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 space 16 and a mouthpiece 18 in abutting coaxial alignment. The aerosol-forming substrate 10, transfer element 12 and aerosol-cooling element 14 and a rear portion of the combustible carbonaceous heat source 4 are wrapped in an outermost wrapper 20. As shown in FIG. 1, a downstream end portion of the outermost wrapper 20 around a rear portion of the aerosol-cooling element 14, the space 16 and the mouthpiece 18 are wrapped in a band of tipping paper 22, which connects the mouthpiece 18 to the other components of the aerosol-generating article 2.

(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 24 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 24 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 a front end of the aerosol-forming substrate 10.

(6) The aerosol-forming substrate 10 is located immediately downstream of the barrier 24 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 26 and a wrapper 28 around and in contact with the gathered crimped sheet of homogenised tobacco material 26. The gathered crimped sheet of homogenised tobacco material 26 comprises a suitable aerosol former such as, for example, glycerine.

(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 30.

(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 mouthpiece 18 is located downstream of the aerosol-cooling element 14. 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 32 such as, for example, cellulose acetate tow of very low filtration efficiency, wrapped in filter plug wrap 34.

(10) In the aerosol-generating article 2 according to the embodiment of the invention shown in FIG. 1, the aerosol-generating article 2 comprises a space 16 between the aerosol-cooling element 14 and the mouthpiece 18.

(11) In other embodiments of the invention (not shown) the space 16 between the aerosol-cooling element 14 and the mouthpiece 18 may be omitted and the mouthpiece 18 may be located immediately downstream of the aerosol-cooling element 14.

(12) In further embodiments of the invention (also not shown) both the aerosol-cooling element and the space 16 between the aerosol-cooling element 14 and the mouthpiece 18 may both be omitted and the mouthpiece 18 may be located immediately downstream of the transfer element 12.

(13) The outermost wrapper 20 comprises a metallised substrate comprising a substrate layer and a metal layer radially outward of the substrate layer, the metal layer having a thickness of less than or equal to about 100 nanometres. The outermost wrapper 20 may further comprise a surface coating on at least a portion of an outer surface of the metal layer of the metallised substrate.

(14) As shown in FIG. 1, the aerosol-generating article 2 further comprises a heat-conducting element 36 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 combustible carbonaceous heat source 4 and a front portion 10a of the aerosol-forming substrate 10. In the aerosol-generating article 2 according to the embodiment of the invention shown in FIG. 1, the aerosol-forming substrate 10 extends downstream beyond the heat-conducting element 36.

(15) The aerosol-generating article 2 according to the embodiment of the invention shown in FIG. 1 comprises one or more air inlets 38 around the periphery of a rear portion of the aerosol-forming substrate 10. As shown in FIG. 1, a circumferential arrangement of air inlets 38 is provided in the wrapper 28 of the aerosol-forming substrate 10 and the overlying outermost wrapper 20 to admit cool air (shown by dotted arrows in FIG. 1) into the aerosol-forming substrate 10.

(16) 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 air inlets 38.

(17) 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 24 and through the heat-conducting element 36.

(18) The heating of the aerosol-forming substrate 10 by conduction releases aerosol former and other volatile and semi-volatile compounds from the gathered crimped sheet of homogenised tobacco material 26. 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 air inlets 38 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 38 of the transfer element 12 and the aerosol-cooling element 14, where they cool and condense. The cooled drawn air and entrained aerosol pass downstream through the space 16 and 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 24 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.

(19) An example of an aerosol-generating article 2 according to the embodiment of the invention shown in FIG. 1 is produced comprising an aerosol-forming substrate 10 comprising a gathered crimped sheet of homogenised tobacco material 26 comprising glycerine, a heat-conducting element 36 formed of aluminium foil, an aerosol-cooling element 14 comprising a gathered crimped sheet of polylactic acid and a mouthpiece 18 comprising a plug of cellulose acetate tow. The outermost wrapper 20 of the aerosol-generating article 2 comprises a metallised substrate comprising a paper layer and an aluminium layer radially outward of the paper layer. The paper layer of the metallised substrate has a basis weight of 50 grams per square metre and a thickness of about 50 micrometres. The aluminium layer of the metallised substrate has a weight of between about 0.04 grams per square metre and about 0.1 grams per square metre and a thickness of between about 15 nanometres and about 35 nanometres. The outermost wrapper 20 further comprises a continuous surface coating on the entire outer surface of the aluminium layer of the metallised substrate. The surface coating is a lacquer comprising 60 percent by weight of calcium carbonate. The surface coating has a weight of about 2.7 grams per square metre and a thickness of about 1 micrometre.

(20) A comparative example of an aerosol-generating article not according to the invention is also produced. The comparative example of the aerosol-generating article not according to the invention is of largely similar construction to the example of the aerosol-generating article 2 according to the embodiment of the invention shown in FIG. 1. However, the outermost wrapper of the comparative example of the aerosol-generating article not according to the invention comprises a laminate comprising a paper layer and a metal layer radially outward of the paper layer. The paper layer of the laminate has a basis weight of 45 grams per square metre and a thickness of about 70 micrometres. The aluminium layer of the laminate has a weight of about 17 grams per square metre and a thickness of about 6.3 micrometres. The outermost wrapper further comprises a continuous surface coating on the entire outer surface of the aluminium layer of the laminate. The surface coating is a lacquer comprising 60 percent by weight of calcium carbonate. The surface coating has a weight of about 2.7 grams per square metre and a thickness of about 1 micrometre.

(21) As shown In Table 1, the length of the front portion 10a of the aerosol-forming substrate 10 in contact with the heat conducting element 36 in the example of the aerosol-generating article 2 according to the embodiment of the invention shown in FIG. 1 is greater than the length of the front portion of the aerosol-forming substrate in contact with heat conducting element in the comparative example of the aerosol-generating article not according to the invention.

(22) The construction and dimensions of the comparative example of the aerosol-generating article not according to the invention are otherwise the same as the construction and dimensions of the example of the aerosol-generating article according to the embodiment of the invention shown in FIG. 1.

(23) TABLE-US-00001 TABLE 1 Comparative Example example Length of heat conducting element 8 mm 5 mm Length of rear portion of combustible 3 mm 3 mm carbonaceous heat source in contact with heat conducting element Length of front portion of aerosol-forming 5 mm 2 mm substrate in contact with heat conducting element

(24) The amount of glycerine (in micrograms) per puff for the example of the aerosol-generating article 2 according to the invention shown in FIG. 1 and the comparative example of the aerosol-generating article not according to the invention is 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. The results are shown in FIG. 2. In FIG. 2, the right hand columns show the puff-by-puff delivery profile for the example of the aerosol-generating article 2 according to the invention shown in FIG. 1 and the left-hand columns show the puff-by-puff delivery profile for the comparative example of the aerosol-generating article not according to the invention.

(25) As shown in FIG. 2, inclusion in the aerosol-generating article according to the invention of an outermost wrapper comprising a metallised substrate comprising a substrate layer and a metal layer radially outward of the substrate layer, wherein the metal layer has a thickness of less than or equal to about 100 nanometres advantageously results in a significant increase in the amount of glycerine in puffs 4 to 12 compared to the aerosol-generating article not according to the invention, which comprises an outermost wrapper comprising a laminate comprising a substrate layer and a metal layer radially outward of the substrate layer, wherein the metal layer has a thickness of greater than 100 nanometres.

(26) In fact the outermost wrapper of the aerosol-generating article according to the invention is so effective in reducing radiative and conductive heat losses compared to the outermost wrapper of the aerosol-generating article not according to the invention that it is necessary to increase the length of the front portion of the aerosol-forming substrate in contact with the heat conducting element in the aerosol-generating article according to the invention compared to the aerosol-generating article not according to the invention in order to prevent burning of the paper layer of the metallised substrate of the outermost wrapper of the aerosol-generating article according to the invention.

(27) The specific embodiment and example 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 embodiment and example described herein are not exhaustive.