AEROSOL-GENERATING ARTICLE HAVING WRAPPER WITH HEAT CONTROL ELEMENT

Abstract

An aerosol-generating article for an aerosol-generating device having a heating element is provided, the article including: a rod of aerosol-generating substrate; and a wrapper at least partially circumscribing the rod, the wrapper including a heat control element on at least one surface of the wrapper, the heat control element including one or more circumferential bands of a heat-shrinkable material, configured such that upon heating of the heat-shrinkable material to a temperature above a shrink temperature thereof, an internal radius of each of the one of more circumferential bands of the heat-shrinkable material is reduced by at least 20 percent compared to an internal radius of the respective circumferential band prior to heating, whereby a portion of the substrate underlying the heat control element is deformed such that a resistance to draw (RTD) of the article is increased, and the shrink temperature is between about 180° C. and about 300° C.

Claims

1.-14. (canceled)

15. An aerosol-generating article for an aerosol-generating device having a heating element, the aerosol-generating article comprising: a rod of aerosol-generating substrate; and a wrapper at least partially circumscribing the rod of aerosol-generating substrate, the wrapper comprising a heat control element on at least one surface of the wrapper, the heat control element comprising one or more circumferential bands of a heat-shrinkable material, configured such that upon heating of the heat-shrinkable material to a temperature above a shrink temperature thereof, an internal radius of each of the one of more circumferential bands of the heat-shrinkable material is reduced by at least 20 percent compared to an internal radius of the respective circumferential band prior to heating, whereby a portion of the aerosol-generating substrate underlying the heat control element is deformed such that a resistance to draw (RTD) of the aerosol-generating article is increased, wherein the shrink temperature is between about 180 degrees Celsius and about 300 degrees Celsius.

16. The aerosol-generating article according to claim 15, wherein upon heating the one or more circumferential bands of heat-shrinkable material to a temperature above the shrink temperature thereof, the RTD of the aerosol-generating article is increased to above 130 mm H.sub.2O.

17. The aerosol-generating article according to claim 15, wherein a reduction in the internal radius of each of the one or more circumferential bands of the heat-shrinkable material upon heating to a temperature above the shrink temperature of the heat-shrinkable material is at least 30 percent compared to the internal radius of the respective circumferential band prior to heating.

18. The aerosol-generating article according to claim 15, wherein said each of the one or more circumferential bands comprises a layer of a heat-shrinkable material on an inner surface of the wrapper.

19. The aerosol-generating article according to claim 18, wherein each layer of heat-shrinkable material has a radial thickness of less than 0.5 mm.

20. The aerosol-generating article according to claim 15, wherein the heat control element extends along at least 75 percent of a length of the rod of aerosol-generating substrate.

21. The aerosol-generating article according to claim 15, wherein the heat control element overlies at least 90 percent of an external surface area of the rod of aerosol-generating substrate.

22. The aerosol-generating article according to claim 15, wherein the heat control element further comprises a plurality of circumferential bands spaced apart along a length of the rod of aerosol-generating substrate.

23. The aerosol-generating article according to claim 15, wherein the heat control element further comprises one or more circumferential bands of a first heat-shrinkable material having a first shrink temperature and one or more circumferential bands of a second heat-shrinkable material having a second shrink temperature higher than the first shrink temperature.

24. The aerosol-generating article according to claim 23, wherein the second shrink temperature is at least 30 degrees Celsius higher than the first shrink temperature.

25. The aerosol-generating article according to claim 15, wherein the one or more circumferential bands extend diagonally around the rod of aerosol-generating substrate relative to a longitudinal axis of the aerosol-generating article.

26. The aerosol-generating article according to claim 15, wherein the one or more circumferential bands of heat-shrinkable material are formed from a material selected from: low density polyethylene (LDPE), linear low density polyethylene cellulose (LLDPE), polyolefin, enhanced polyethylene resin (EPE), and combinations thereof.

27. The aerosol-generating article according to claim 15, wherein the heat-shrinkable material is configured to reach or exceed the shrink temperature of the heat-shrinkable material when the aerosol-generating substrate is internally heated to a temperature above an internal threshold temperature or when the aerosol-generating substrate is externally heated to a temperature above an external threshold temperature, wherein the internal threshold temperature is at least about 350 degrees Celsius, and wherein the external threshold temperature is below about 200 degrees Celsius.

28. An aerosol-generating system, comprising: an aerosol-generating article according to claim 15; and an aerosol-generating device configured to receive the aerosol-generating article, the aerosol-generating device comprising a heater element configured to heat the rod of aerosol-generating material, wherein the heater element is controlled during use to operate below a maximum operating temperature, wherein the heat control element of the aerosol-generating article is configured such that the shrink temperature of the heat-shrinkable material is not exceeded during use of the aerosol-generating system with the heater element operating below the maximum operating temperature.

Description

[0095] The invention will now be further described with reference to the figures in which:

[0096] FIG. 1 shows a schematic perspective view of an aerosol-generating article according to a first embodiment of the invention, with the wrapper of the aerosol-generating substrate unwrapped;

[0097] FIG. 2 shows a schematic perspective view of the aerosol-generating article of FIG. 1, after activation of the heat control element;

[0098] FIG. 3 shows a schematic perspective view of an aerosol-generating article according to a second embodiment of the invention, with the wrapper of the aerosol-generating substrate unwrapped;

[0099] FIG. 4 shows a schematic perspective view of the aerosol-generating article of FIG. 3, after activation of the heat control element;

[0100] FIG. 5 shows a schematic perspective view of an aerosol-generating article according to a third embodiment of the invention, with the wrapper of the aerosol-generating substrate unwrapped;

[0101] FIG. 6 shows a schematic perspective view of the aerosol-generating article of FIG. 5, after activation of the heat control element;

[0102] FIG. 7 is a schematic cross-sectional view of an aerosol-generating system comprising an aerosol-generating device and an aerosol generating article according to the invention; and

[0103] FIG. 8 is a schematic cross-sectional view of the electrically heated aerosol generating device of FIG. 7.

[0104] The aerosol-generating article 10 shown in FIG. 1 comprises four elements arranged in coaxial alignment: an aerosol-generating substrate 20, a support element 30, an aerosol-cooling element 40, and a mouthpiece 50. The aerosol-generating substrate 20 is circumscribed by a wrapper 60, described in more detail below. Each of the other elements is circumscribed by a corresponding plug wrap (not shown). These four elements are arranged sequentially and are circumscribed by an outer wrapper (not shown) 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.

[0105] 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.

[0106] The aerosol-generating substrate 20 is located at the extreme distal or upstream end of the aerosol-generating article 10. In the embodiment illustrated in FIG. 1, the aerosol-generating substrate 20 comprises a gathered sheet of crimped homogenised tobacco material.

[0107] The crimped sheet of homogenised tobacco material comprises glycerin as an aerosol former.

[0108] The aerosol-generating substrate 20 is circumscribed by a wrapper 60 comprising a heat control element 62 on the inner surface. The heat control element 62 comprises a single layer 64 of a heat-shrinkable material having a shrink temperature of around 200 degrees Celsius, which covers the entire inner surface of the wrapper 60 and therefore extends along the full length of the aerosol-generating substrate 20. In the assembled aerosol-generating article 10, with the wrapper surrounding the aerosol-generating substrate 20, the layer 64 of heat-shrinkable material forms a band 66 which circumscribes the entire aerosol-generating substrate 20.

[0109] Prior to activation of the heat control element 62, the band 66 of heat-shrinkable material has an internal radius substantially corresponding to the outer radius of the underlying aerosol-generating substrate 20. The heat control element 62 therefore has a negligible effect on RTD and will not impact the normal use of the aerosol-generating article 10.

[0110] If the shrink temperature of 200 degrees Celsius is exceeded at the inner surface of the wrapper 60 due to overheating of the aerosol-generating article 10, the heat control element 62 will activate and the band 66 of the heat-shrinkable material will radially shrink so that the internal radius of the band is reduced by over 20 percent. As shown in FIG. 2, this radial shrinkage of the band 66 causes compression and deformation of the aerosol-generating substrate 20 which causes an increase in RTD to a level above 130 mm H.sub.2O. It will therefore become difficult for the consumer to draw air through the aerosol-generating article and further use of the aerosol-generating article will no longer be possible.

[0111] The support element 30 is in the form of a hollow cellulose acetate tube located immediately downstream of the aerosol-generating substrate 30 and abutting the aerosol-generating substrate 20. The support element 30 locates the aerosol-generating 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 is in place to prevent the aerosol-generating 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-generating 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-generating substrate 20.

[0112] 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-generating 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 60. 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.

[0113] 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.

[0114] FIG. 3 shows an aerosol-generating article 110 according to a second embodiment of the present invention. The aerosol-generating article 110 has a similar structure to the aerosol-generating article 10 shown in FIG. 1 and described above, except that the wrapper 160 circumscribing the aerosol-generating substrate 20 comprises a heat control element 162 having a different structure to that described above. All other components of the aerosol-generating article 110 are as described above in relation to the aerosol-generating article 10 shown in FIG. 1 and the same reference numerals have been applied.

[0115] The heat control element 162 of the aerosol-generating article 110 shown in FIG. 3 comprises a plurality of diagonal strips 164 of a heat-shrinkable material on the inner surface of the wrapper 160. The diagonal strips 164 are substantially parallel to each other and spaced apart from each other in a longitudinal direction along the wrapper 160. The heat control element 162 covers substantially the entire inner surface of the wrapper 160 and therefore extends along the full length of the aerosol-generating substrate 20. As in the first embodiment, the strips are formed of a heat-shrinkable material having a shrink temperature of around 200 degrees Celsius. In the assembled aerosol-generating article 110, with the wrapper 160 surrounding the aerosol-generating substrate 20, each of the strips 164 of heat-shrinkable material forms a diagonal band 166 which circumscribes the aerosol-generating substrate 20.

[0116] FIG. 4 shows the aerosol-generating article 110 after activation of the heat control element 162 and the resultant shrinkage of the diagonal bands 166. Activation occurs in the same way as described above in relation to the first embodiment, with a corresponding effect on the RTD of the aerosol-generating article 110.

[0117] FIG. 5 shows an aerosol-generating article 210 according to a third embodiment of the present invention. The aerosol-generating article 210 has a similar structure to the aerosol-generating article 10 shown in FIG. 1 and described above, except that the wrapper 260 circumscribing the aerosol-generating substrate 20 comprises a heat control element 262 having a different structure to that described above. All other components of the aerosol-generating article 210 are as described above in relation to the aerosol-generating article 10 shown in FIG. 1 and the same reference numerals have been applied.

[0118] The heat control element 262 of the aerosol-generating article 210 shown in FIG. 5 comprises a first strip 264 of a first heat-shrinkable material and a second strip 265 of a second heat-shrinkable material. The first strip 264 and the second strip 265 are provided adjacent to each other on the inner surface of the wrapper 260, with a small space between. The first strip 264 and the second strip 265 have substantially the same width as each other and in combination, cover substantially the entire inner surface of the wrapper 260, apart from the space between the strips 264, 265. The first heat-shrinkable material has a different shrink temperature to the second heat-shrinkable material.

[0119] In the assembled aerosol-generating article 210, with the wrapper 260 surrounding the aerosol-generating substrate 20, the first 264 and second 265 strips of heat-shrinkable material form first 266 and second 267 bands of heat-shrinkable material, respectively, which circumscribe the aerosol-generating substrate 20.

[0120] FIG. 6 shows the aerosol-generating article 210 after activation of the heat control element 262 and heating of the heat control element 262 to a temperature that is above both the first shrink temperature and the second shrink temperature. In this stage, both the first 266 and second 267 bands of heat-shrinkable material have radially shrunk to cause deformation of the underlying aerosol-generating substrate 20. Activation occurs in a similar way to that described above in relation to the first embodiment, with a corresponding effect on the RTD of the aerosol-generating article 210.

[0121] FIG. 7 illustrates a portion of an aerosol-generating system 300 comprising an aerosol-generating device 310 and an aerosol-generating article 10 according to the first embodiment described above and shown in FIG. 1. It will be appreciated that the aerosol-generating device 310 could be used in combination with an alternative aerosol-generating article according to the invention, such as any of the other embodiments described above and shown in the Figures.

[0122] The aerosol-generating device 310 comprises a heating element 320. As shown in FIG. 8, the heating element 320 is mounted within an aerosol-generating article receiving chamber of the aerosol-generating device 310. In use, the user inserts the aerosol-generating article 10 into the aerosol-generating article receiving chamber of the aerosol-generating device 310 such that the heating element 320 is directly inserted into the aerosol-generating substrate 20 of the aerosol-generating article 10 as shown in FIG. 8. In the embodiment shown in FIG. 8, the heating element 320 of the aerosol-generating device 310 is a heater blade.

[0123] The aerosol-generating device 310 comprises a power supply and electronics (shown in FIG. 3) that allow the heating element 320 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 310. 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 airflow is illustrated by arrows in FIG. 8.

[0124] The support element 30 acts to resist the penetration force experienced by the aerosol-generating article 10 during insertion of the heating element 320 of the aerosol-generating device 310 into the aerosol-generating substrate 20. The support element 30 thereby resists downstream movement of the aerosol-generating substrate 20 within the aerosol-generating article 10 during insertion of the heating element 320 of the aerosol-generating device 310 into the aerosol-generating substrate 20.

[0125] Once the internal heating element 320 is inserted into the aerosol-generating substrate 20 of the aerosol-generating article 10 and the heating element 320 is actuated, the aerosol-generating substrate 20 of the aerosol-generating article 10 is heated to a temperature of approximately 350 degrees Celsius by the heating element 320 of the aerosol-generating device 310. At this temperature, volatile compounds are evolved from the aerosol-generating 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-generating 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.

[0126] 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.

[0127] In FIG. 8, the components of the aerosol-generating device 310 are shown in a simplified manner. Particularly, the components of the aerosol-generating device 310 are not drawn to scale in FIG. 8. Components that are not relevant for the understanding of the embodiment have been omitted to simplify FIG. 8.

[0128] As shown in FIG. 8, the aerosol-generating device 310 comprises a housing 330. The heating element 320 is mounted within an aerosol-generating article receiving chamber within the housing 330. The aerosol-generating article 10 (shown by dashed lines in FIG. 9) is inserted into the aerosol-generating article receiving chamber within the housing 330 of the aerosol-generating device 310 such that the heating element 320 is directly inserted into the aerosol-generating substrate 20 of the aerosol-generating article 10.

[0129] Within the housing 330 there is an electrical energy supply 340, for example a rechargeable lithium ion battery. A controller 350 is connected to the heating element 320, the electrical energy supply 340, and a user interface 360, for example a button or display. The controller 350 controls the power supplied to the heating element 320 in order to regulate its temperature.

[0130] During this normal usage of the aerosol-generating articles according to the invention with the compatible aerosol-generating device 310 shown in FIGS. 7 and 8, the heat control element 62 within the wrapper 60 of the aerosol-generating substrate 20 of the aerosol-generating article is unaffected.

[0131] In the event that the aerosol-generating articles according to the invention are used with a non-compatible device and are overheated to above a preferred maximum operating temperature, the heat control element will activate upon reaching the shrink temperature of the heat-shrinkable material forming the band or bands of the heat control element. As described above in relation to the separate embodiments, upon activation of the heat control element, the bands of heat-shrinkable material radially shrink by at least 20 percent, causing significant compression of the aerosol-generating substrate. The RTD of the aerosol-generating article increases to a level at which the consumer is no longer able to draw air through the aerosol-generating article. After activation of the heat control element, the aerosol-generating article can therefore no longer be used.