U.S. patent application number 16/976353 was filed with the patent office on 2021-05-20 for aerosol-generating article having wrapper with heat control element.
This patent application is currently assigned to Philip Morris Products S.A.. The applicant listed for this patent is Philip Morris Products S.A.. Invention is credited to Rui Nuno BATISTA, Evan JOCHNOWITZ.
Application Number | 20210145044 16/976353 |
Document ID | / |
Family ID | 1000005382962 |
Filed Date | 2021-05-20 |
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United States Patent
Application |
20210145044 |
Kind Code |
A1 |
BATISTA; Rui Nuno ; et
al. |
May 20, 2021 |
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.degree. C. and
about 300.degree. C.
Inventors: |
BATISTA; Rui Nuno;
(Neuchatel, CH) ; JOCHNOWITZ; Evan; (Neuchatel,
CH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Philip Morris Products S.A. |
Neuchatel |
|
CH |
|
|
Assignee: |
Philip Morris Products S.A.
Neuchatel
CH
|
Family ID: |
1000005382962 |
Appl. No.: |
16/976353 |
Filed: |
April 9, 2019 |
PCT Filed: |
April 9, 2019 |
PCT NO: |
PCT/EP2019/058984 |
371 Date: |
August 27, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A24D 1/025 20130101;
A24F 40/53 20200101; A24F 40/20 20200101; A24D 1/20 20200101 |
International
Class: |
A24D 1/20 20060101
A24D001/20; A24D 1/02 20060101 A24D001/02; A24F 40/20 20060101
A24F040/20; A24F 40/53 20060101 A24F040/53 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 9, 2018 |
EP |
18166415.2 |
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
[0001] The present invention relates to a heated aerosol-generating
article incorporating a wrapper with a heat control element, and to
an aerosol-generating system comprising such a heated
aerosol-generating article.
[0002] Aerosol-generating articles in which an aerosol-generating
substrate, such as a tobacco-containing substrate, is heated rather
than combusted, are known in the art. Typically in such heated
smoking articles, an aerosol is generated by the transfer of heat
from a heat source to a physically separate aerosol-generating
substrate or material, which may be located in contact with,
within, around, or downstream of the heat source. During use of the
aerosol-generating article, volatile compounds are released from
the aerosol-generating substrate by heat transfer from the heat
source and are entrained in air drawn through the
aerosol-generating article. As the released compounds cool, they
condense to form an aerosol.
[0003] A number of prior art documents disclose aerosol-generating
devices for consuming or smoking heated aerosol-generating
articles. Such devices include, for example, electrically heated
aerosol-generating devices in which an aerosol is generated by the
transfer of heat from one or more electrical heating elements of
the aerosol-generating device to the aerosol-generating substrate
of a heated aerosol-generating article. One advantage of such
electrically heated aerosol-generating devices is that they
significantly reduce sidestream smoke.
[0004] In such aerosol-generating devices, the heating element will
typically be configured to heat the aerosol-generating substrate
within a defined temperature range which has been selected by the
manufacturer to provide an optimal aerosol release profile from the
aerosol-generating article. The aerosol-generating article and
aerosol-generating device are therefore specifically adapted for
use in conjunction with each other.
[0005] However, where an aerosol-generating article is
inadvertently or intentionally used with a non-compatible
(incompatible) aerosol-generating device, an optimal aerosol
release profile is very unlikely to be provided to the consumer.
The construction of the heating element in the non-compatible
device will typically be different to that of the compatible device
and the form of heating of the aerosol-generating substrate is
therefore likely to be different. Furthermore, the heater may not
be operated in the same way within the same temperature ranges, so
that the aerosol-generating substrate will not be heated under the
same temperature profile as in a compatible device. As a result,
the properties of the aerosol released from the substrate will not
be as intended by the manufacturer. The experience of the consumer
will likely therefore be adversely affected as a result of using
the aerosol-generating article with a non-compatible device.
[0006] Particular problems may arise when an aerosol-generating
article is used in a device that heats the aerosol-generating
substrate to a higher temperature than intended, such that at least
a part of the substrate becomes overheated. This may occur, for
example, when an aerosol-generating article that is adapted to be
heated by an internal heating element is instead used in an
aerosol-generating device that heats the aerosol-generating article
externally. Such devices that heat the substrate from the outside
during use typically require much higher operating temperatures and
therefore at least the outer parts of the substrate are likely to
be heated to a much higher temperature than would be provided using
an internal heating element.
[0007] It would be desirable to provide a novel arrangement of an
aerosol-generating article which prevents the use of the
aerosol-generating article with a non-compatible aerosol-generating
device and in particular, with a non-compatible device that heats
the aerosol-generating substrate to a higher temperature than is
intended. It would be further desirable to provide such a novel
arrangement of an aerosol-generating article which does not
adversely impact the use of the aerosol-generating article under
normal heating conditions in a compatible device. It would be
particularly desirable if such a novel arrangement of an
aerosol-generating article could be readily provided without
significantly impacting the construction of the aerosol-generating
article or the method and apparatus used for the production of the
aerosol-generating article.
[0008] According to a first aspect of the present invention, there
is provided a heated aerosol-generating article for use with an
aerosol-generating device having a heating element, the heated
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 comprises one or more circumferential bands of a
heat-shrinkable material, wherein upon heating of the
heat-shrinkable material to a temperature above the shrink
temperature thereof, the 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 the internal radius of the
respective circumferential band prior to heating. As a result, the
portion of the aerosol-generating substrate underlying the heat
control element is deformed such that the resistance to draw (RTD)
of the aerosol-generating article is increased.
[0009] According to a second aspect of the present invention, there
is provided an aerosol-generating system comprising an
aerosol-generating article according to the first aspect of the
invention, as defined above; and an aerosol-generating device
adapted to receive the aerosol-generating article. The
aerosol-generating device comprises a heater element configured to
heat the rod of aerosol-generating material during use wherein the
heater element is controlled during use to operate below a maximum
operating temperature. The heat control element of the
aerosol-generating article is adapted 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.
[0010] As used herein, the term "heated aerosol-generating article"
refers to an aerosol-generating article for producing an aerosol
comprising an aerosol-generating substrate that is intended to be
heated rather than combusted in order to release volatile compounds
that can form an aerosol. Such articles are commonly referred to as
"heat-not-burn" products.
[0011] As used herein, the term "aerosol-generating substrate"
refers to a substrate capable of releasing upon heating volatile
compounds, which can form an aerosol. The aerosol generated from
aerosol-generating substrates of aerosol-generating articles
described herein may be visible or invisible and may include
vapours (for example, fine particles of substances, which are in a
gaseous state, that are ordinarily liquid or solid at room
temperature) as well as gases and liquid droplets of condensed
vapours.
[0012] As used herein, the term "band of heat-shrinkable material"
refers to an annular ring or tube of material that shrinks radially
when heated above the "shrink temperature". Suitable heat-shrink
tubing for use in forming the circumferential bands of
heat-shrinkable material in the wrapper of the present invention
would be well known to the skilled person and examples of suitable
materials are provided below.
[0013] As used herein, the term "resistance to draw" (RTD) refers
to the pressure required to force air through the full length of
the object under test at the rate of 17.5 millilitres per second at
22 degrees Celsius and 101 kilopascals (760 Torr). Resistance to
draw is expressed in units of millimetres water gauge (mmWG or mm
H.sub.2O) and is measured in accordance with ISO 6565:2011.
[0014] As used herein, the term "rod" refers to a generally
cylindrical element of substantially polygonal cross-section and
preferably of circular, oval or elliptical cross-section.
[0015] As used herein, the term "longitudinal" refers to the
direction corresponding to the main longitudinal axis of the
aerosol-generating article, which extends between the upstream and
downstream ends of the aerosol-generating article. During use, air
is drawn through the aerosol-generating article in the longitudinal
direction. The term "transverse" refers to the direction that is
perpendicular to the longitudinal axis.
[0016] As used herein, the terms "upstream" and "downstream"
describe the relative positions of elements, or portions of
elements, of the aerosol-generating article in relation to the
direction in which the aerosol is transported through the
aerosol-generating article during use.
[0017] Aerosol-generating articles according to the present
invention are suitable for use in an aerosol-generating system
comprising an electrically heated aerosol-generating device having
an internal heating element for heating the aerosol-generating
substrate. For example, aerosol-generating articles according to
the invention find particular application in aerosol-generating
systems comprising an electrically heated aerosol-generating device
having an internal heater blade which is adapted to be inserted
into the rod of aerosol-generating substrate. Aerosol-generating
articles of this type are described in the prior art, for example,
in European patent application EP-A-0 822 670.
[0018] As used herein, the term "aerosol-generating device" refers
to a device comprising a heating element that interacts with the
aerosol-generating substrate of the aerosol-generating article to
generate an aerosol.
[0019] As described above, aerosol-generating articles according to
the present invention incorporate a heat control element on at
least one surface of the wrapper circumscribing the
aerosol-generating substrate, wherein the heat control element
comprises one or more circumferential bands of a heat-shrinkable
material. The heat control element provides a safe and effective
means for preventing use of the aerosol-generating article in a
non-compatible device that heats the aerosol-generating article
excessively above a desired operating temperature range. The heat
control element therefore provides means for prevention of
overheating of the aerosol-generating article.
[0020] The positioning of the heat control element on the wrapper,
surrounding the outside of the aerosol-generating substrate makes
it particularly responsive to overheating of the aerosol-generating
article due to use of a non-compatible device having a peripheral
heater that heats the aerosol-generating substrate externally, as
described above.
[0021] The heat control element is adapted such that above a
defined threshold temperature, corresponding to the shrink
temperature of the heat-shrinkable material, the internal radius of
the one or more bands of heat-shrinkable material is significantly
reduced, to "activate" the heat control element. The radial
shrinkage of the one or more bands of heat-shrinkable material
causes the underlying aerosol-generating substrate to be
compressed. This compression and deformation of the underlying
aerosol-generating substrate makes it difficult or impossible for
the consumer to draw air through the aerosol-generating article,
thereby increasing the resistance to draw (RTD) of the
aerosol-generating article. In this way, the consumer will be
alerted to the fact that he is attempting to use the
aerosol-generating article with a non-compatible aerosol-generating
device and will not be able to continue with smoking of the
aerosol-generating article.
[0022] As discussed in more detail below, the heat-shrinkable
material from which the bands of the heat control element are
formed is selected with an appropriate shrink temperature that will
only be reached or exceeded when the aerosol-generating article is
overheated, that is, heated above the intended operating
temperature range. In other words, the one or more bands of
heat-shrinkable material will only shrink at excessive operating
temperatures. The threshold temperature at which the heat control
element is activated will correspond to the temperature reached at
the surface of the wrapper incorporating the heat control element
when the aerosol-generating substrate is heated above the maximum
desired temperature, as determined by the manufacturer.
[0023] Advantageously, when the aerosol-generating articles
according to the invention are heated normally in a compatible
aerosol-generating device, the presence of the heat control element
will not perceivably impact the consumer experience. In particular,
the heat control element should not have an impact on the RTD of
the aerosol-generating article, or on the composition and
properties of the aerosol generated from the underlying
aerosol-generating substrate during use.
[0024] The heat control element comprising the one or more bands of
heat-shrinkable material can be conveniently incorporated into the
wrapper circumscribing the aerosol-generating substrate of an
aerosol-generating article, without impacting the arrangement of
the other components of the article. Furthermore, the heat control
element can conveniently be incorporated into the wrapper prior to
the application of the wrapper around the aerosol-generating
substrate. The inclusion of the heat control element should not
therefore significantly impact the manufacture of the
aerosol-generating articles. Aerosol-generating articles according
to the invention can therefore advantageously be made using
existing high speed methods and apparatus.
[0025] As defined above, the shrinkage of the one or more bands of
the heat-shrinkable material brings about a reduction in the
internal radius of each band of at least about 20 percent compared
to the original internal radius of the band, prior to heating of
the aerosol-generating substrate. This is to ensure that sufficient
deformation of the aerosol-generating substrate occurs that the RTD
of the aerosol-generating article will be significantly impacted by
the activation of the heat control element. Preferably, the
reduction in the internal radius of each of the one or more
circumferential bands of heat-shrinkable material upon heating to a
temperature above the shrink temperature of the heat-shrinkable
material is at least about 30 percent compared to the internal
radius of the respective circumferential band prior to heating.
[0026] Alternatively or in addition, the reduction in the internal
radius of each of the one or more circumferential bands of
heat-shrinkable material upon heating to a temperature above the
shrink temperature of the heat-shrinkable material is preferably no
more than about 50 percent compared to the internal radius of the
respective circumferential band prior to heating.
[0027] These values of radial shrinkage correspond to the shrinkage
of the bands when they are in position over the aerosol-generating
substrate. The degree of shrinkage achieved by the bands may depend
on the properties of the underlying aerosol-generating substrate
and the aerosol-generating substrate will resist the shrinkage to a
certain extent. The degree of shrinkage achieved by the band in
isolation from the aerosol-generating substrate, which may be
defined for example in terms of a "shrink ratio", will typically be
higher.
[0028] The radial shrinkage of the one or more circumferential
bands of heat-shrinkable material has the effect of increasing the
RTD of the aerosol-generating article due to the compression of the
underlying aerosol-generating substrate, as described above. The
increase in RTD should be sufficiently large that it is detectable
by the consumer to alert them to the unintended use of the
aerosol-generating article. For example, the increase in RTD may be
at least 30 mm H.sub.2O or at least 50 mm H.sub.2O, depending upon
the RTD provided under normal operating conditions.
[0029] Preferably, the RTD is increased to a level that makes it
very difficult, and preferably substantially impossible, for the
consumer to continue to draw air through the aerosol-generating
article. Preferably, the RTD is therefore increased to above about
130 mm H.sub.2O, more preferably above about 140 mm H.sub.2O and
most preferably above about 150 mm H.sub.2O.
[0030] The RTD may increase up to about 300 mm H.sub.2O.
Alternatively, the RTD may increase up to about 250 mm H.sub.2O.
Alternatively, the RTD may increase up to about 200 mm H.sub.2O.
Alternatively, the RTD may increase up to about 180 mm H.sub.2O.
Such upper limits of RTD are sufficient to render the
aerosol-generating article substantially unusable, in the sense
that such upper limits of RTD make it very difficult for the
consumer to draw air through the aerosol-generating article.
[0031] Preferably, the RTD of the aerosol-generating article prior
to activation of the heat control element is between about 80 mm
H.sub.2O and about 90 mm H.sub.2O.
[0032] The one or more circumferential bands of heat-shrinkable
material forming the heat control element may be provided on the
inner surface of the wrapper, the outer surface of the wrapper, or
both the inner surface and the outer surface of the wrapper. In
certain embodiments it may be preferably to provide the heat
control element on the inner surface of the wrapper to minimise the
visibility of the bands of heat-shrinkable material to the
consumer.
[0033] Each of the circumferential bands is preferably provided by
a layer of the heat-shrinkable material applied to the appropriate
surface of the wrapper. For example, the heat-shrinkable material
may be incorporated onto the surface of the wrapper by lamination
during manufacture of the wrapper. The layer of heat-shrinkable
material will form a band or ring circumscribing the
aerosol-generating substrate when the wrapper is wrapped
circumferentially around the aerosol-generating substrate.
Preferably, each of the bands extends circumferentially all of the
way around the aerosol-generating substrate to form an annular band
or ring, so that the compressive effect of the shrinkage of the
band on the underlying aerosol-generating substrate is
maximised.
[0034] Preferably, the layer of heat-shrinkable material forming
each circumferential band has a radial thickness of less than about
0.5 millimetres, more preferably less than about 0.3 millimetres
and more preferably less than about 0.2 millimetres. The selection
of a relatively thin layer of the heat-shrinkable material may
advantageously optimise the thermal sensitivity of the heat control
element. Furthermore, the impact of the incorporation of the heat
control element on the overall dimensions of the aerosol-generating
article can be minimised.
[0035] Alternatively or in addition, the layer of heat-shrinkable
material forming each circumferential band has a radial thickness
of at least about 0.05 millimetres. This ensures that a sufficient
compressive force can be provided by the bands of heat-shrinkable
material to achieve the desired increase in RTD of the
aerosol-generating article.
[0036] Preferably, the heat control element including the one or
more circumferential bands of heat-shrinkable material extends
along at least about 50 percent of the length of the rod of
aerosol-generating substrate, more preferably along at least about
75 percent of the length. In some embodiments, the heat control
element extends along 100 percent of the length of the
aerosol-generating substrate. This is based on a measurement of the
longitudinal distance between the most upstream portion of the heat
control element and the most downstream portion of the heat control
element, including any spaces provided between bands.
[0037] Alternatively or in addition, the heat control element
including the one or more circumferential bands of heat-shrinkable
material preferably overlies at least about 60 percent of the
external surface are of the rod of aerosol-generating substrate,
more preferably at least about 75 percent and most preferably at
least about 90 percent. This is based on a measurement of the
overall area covered by the heat control element between the most
upstream portion of the heat control element and the most
downstream portion of the heat control element, including any
spaces provided between bands.
[0038] By providing sufficient coverage of the heat control element
along and around the rod of aerosol-generating substrate, a
sufficient deformation of the aerosol-generating substrate can be
achieved upon shrinkage of the bands of heat-shrinkable material to
bring about the desired increase in RTD when the heat control
element is activated.
[0039] The arrangement of the one or more circumferential bands of
heat-shrinkable material in the heat control element may vary, for
example, depending on the properties of the heat-shrinkable
material selected. In some preferred embodiments, the heat control
element comprises a single band of heat-shrinkable material. The
single band may extend longitudinally along only a portion of the
rod of aerosol-generating substrate or the single band may extend
along substantially the entire rod of aerosol-generating
substrate.
[0040] Where a single band is provided, the width of the band is
preferably at least about 2 millimetres, more preferably at least
about 3 millimetres. The "width" of the band corresponds to the
dimension of the band in the longitudinal direction of the
aerosol-generating article. As described above, in certain
preferred embodiments, the single band of heat-shrinkable material
circumscribes the rod of aerosol-generating substrate along
substantially its full length so that the width of the band
corresponds to the length of the rod of aerosol-generating
substrate.
[0041] In alternative preferred embodiments, the heat control
element comprises a plurality of circumferential bands of
heat-shrinkable material which are spaced apart in a longitudinal
direction along the length of the rod of aerosol-generating
substrate. This arrangement of a plurality of bands may
advantageously enable the heat control element as a whole to extend
overall over a greater proportion of the rod of aerosol-generating
substrate to be covered by the heat control element but using less
material than would be required for a single band covering the same
proportion of the rod.
[0042] Preferably, the heat control element comprises between about
2 circumferential bands and about 8 circumferential bands of
heat-shrinkable material spaced apart along at least a portion of
the length of the rod of aerosol-generating substrate, more
preferably between about 2 circumferential bands and about 5
circumferential bands.
[0043] Where a plurality of circumferential bands of
heat-shrinkable material are provided, the bands may have
substantially the same width and thickness as each other, or the
bands may vary in at least one of the width and the thickness.
[0044] Where a plurality of circumferential bands of
heat-shrinkable material are provided, the width of each band and
the spacing between the bands can be adapted depending on the total
number of bands in the heat control element, to provide the desired
level of coverage along the rod of aerosol-generating substrate.
Preferably, the width of each band is at least 1 millimetre, more
preferably at least 2 millimetres.
[0045] For embodiments comprising a heat control element with a
plurality of circumferential bands of heat-shrinkable material, as
described above, all of the bands may be formed of the same
heat-shrinkable material. Alternatively, the heat control element
may comprise 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. For example, the heat control element may comprise a
single band of the first heat-shrinkable material and a single band
of the second heat-shrinkable material, wherein the bands are
provided adjacent to each other, with or without a space.
Alternatively, the heat control element may comprise a plurality of
alternating bands of the first and second heat-shrinkable
materials.
[0046] Preferably, the second shrink temperature of the second
heat-shrinkable material is at least 30 degrees Celsius higher than
the first shrink temperature of the first heat-shrinkable
material.
[0047] The use of a combination of two or more different
heat-shrinkable materials advantageously enables a range of shrink
temperatures to be provided for the same aerosol-generating
article, so that the heat control element can potentially be
activated over a wider range of overheating conditions. As such,
the heat control element can be adapted to activate in response to
use of the aerosol-generating article with a variety of different
non-compatible devices, which may have different heater locations
and heating profiles to each other.
[0048] For any embodiment of the present invention, each of the
circumferential bands may be provided substantially perpendicular
to the longitudinal axis of the aerosol-generating article such
that the longitudinal coverage of the band substantially
corresponds to its width. Alternatively, each of the
circumferential bands may extend diagonally around the rod of
aerosol-generating substrate relative to the longitudinal axis of
the aerosol-generating article so that the longitudinal coverage of
the band is greater than its width. With such an arrangement, the
band extends along the rod of aerosol-generating substrate in a
longitudinal direction, as well as circumferentially around it.
This may improve the overall coverage of the heat control element
over the rod of aerosol-generating substrate, without the need to
necessarily increase the amount of material required.
[0049] A suitable heat-shrinkable material should be selected for
the heat control element, wherein the heat-shrinkable material has
an appropriate shrink temperature to ensure that there is no risk
of the heat control element activating when the aerosol-generating
article is heated to within a normal operating temperature range
but so that the bands of heat-shrinkable material shrink as rapidly
as possible when the aerosol-generating article is heated to a
temperature above this range. Suitable heat-shrinkable materials
are well known and the skilled person will be readily able to
select a material having an appropriate shrink temperature,
depending on the temperature at which it is intended for the heat
control element to be activated.
[0050] The aerosol-generating articles are intended to be used in a
device comprising a heater blade which is inserted into the rod of
aerosol-generating article and heats the aerosol-generating article
internally. The temperature within the aerosol-generating substrate
will decrease with increasing radial distance from the heater blade
and will typically be lowest at the surface of the rod of
aerosol-generating substrate, where the heat control element will
be positioned. Using thermocouples, it is possible to measure the
temperature reached at the wrapper when the aerosol-generating
article is heated to within the normal operating temperature so
that the threshold temperature at which the heat control element
activates can be set above this.
[0051] Preferably, the shrink temperature of the heat-shrinkable
material forming the one or more circumferential bands of the heat
control element is at least about 180 degrees Celsius, more
preferably at least about 200 degrees Celsius and most preferably
at least about 220 degrees Celsius. This range of shrink
temperature will ensure that the heat control element is not
activated during heating of the rod of aerosol-generating substrate
under normal operating conditions.
[0052] Preferably, the shrink temperature of the heat-shrinkable
material forming the one or more circumferential bands of the heat
control element is no more than about 300 degrees Celsius, more
preferably no more than 280 degrees Celsius. This ensures that the
heat control element is sufficiently sensitive to heating of the
aerosol-generating substrate above the maximum desired
temperature.
[0053] Preferably, the heat-shrinkable material is a polymeric
material, most preferably a thermoplastic polymeric material.
Suitable polymeric materials would be known to the skilled person
but include: low density polyethylene (LDPE), linear low density
polyethylene cellulose (LLDPE), polyolefin, enhanced polyethylene
resin (EPE) and combinations thereof.
[0054] Preferably, the heat-shrinkable material is substantially
transparent.
[0055] Preferably, 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 said
internal threshold temperature is at least about 350 degrees
Celsius and wherein said external threshold temperature is below
about 200 degrees Celsius. This enables the heat-shrinkable
material to not be activated during the intended internal heating
of the aerosol-generating substrate in an aerosol-generating
device, but enables the heat-shrinkable material to be activated
when externally heated. This ensures that the heat-shrinkable
material is activated when the heated aerosol-generating article is
used with an incompatible aerosol-generating device, but not
activated when the article is used with a compatible
aerosol-generating device. Said heat-shrinkable material
corresponds to any of the heat-shrinkable materials forming the
heat control element.
[0056] The "internal threshold temperature" refers to a temperature
within the aerosol-generating substrate, when it is internally
heated, at which the heat-shrinkable material reaches or exceeds
its corresponding shrink temperature.
[0057] The "external threshold temperature" refers to a temperature
at the outer surface of the aerosol-generating substrate, when it
is externally heated, at which the heat-shrinkable material reaches
or exceeds its corresponding shrink temperature.
[0058] The internal threshold temperature may be at least about 300
degrees Celsius. Alternatively, the internal threshold temperature
may be at least about 400 degrees Celsius. Alternatively, the
internal threshold temperature may be at least about 450 degrees
Celsius.
[0059] The external threshold temperature may be below about 150
degrees Celsius. Alternatively, the external threshold temperature
may be below about 250 degrees Celsius. Alternatively, the external
threshold temperature may be below about 300 degrees Celsius.
Alternatively, the external threshold temperature may be below
about 350 degrees Celsius. Alternatively, the external threshold
temperature may be below about 400 degrees Celsius. Alternatively,
the external threshold temperature may be below about 450 degrees
Celsius.
[0060] The aerosol-generating articles according to the present
invention may comprise a plurality of elements, including the rod
of aerosol-generating substrate and the heat control component,
assembled within a wrapper, such as a cigarette paper.
[0061] The rod of aerosol-generating substrate is formed of an
aerosol-forming material, which is particularly preferably
homogenised tobacco material.
[0062] As used herein, the term "homogenised tobacco material"
encompasses any tobacco material formed by the agglomeration of
particles of tobacco material. Sheets or webs of homogenised
tobacco material are formed by agglomerating particulate tobacco
obtained by grinding or otherwise powdering of one or both of
tobacco leaf lamina and tobacco leaf stems. In addition,
homogenised tobacco material may comprise a minor quantity of one
or more of tobacco dust, tobacco fines, and other particulate
tobacco by-products formed during the treating, handling and
shipping of tobacco. The sheets of homogenised tobacco material may
be produced by casting, extrusion, paper making processes or other
any other suitable processes known in the art.
[0063] In preferred embodiments, the rod comprises one or more
sheets of a homogenised tobacco material that have been gathered to
form a plug and circumscribed by an outer wrapper. As used herein
with reference to the invention, the term "sheet" describes a
laminar element having a width and length substantially greater
than the thickness thereof. As used herein with reference to the
invention, the term "gathered" describes a sheet that is
convoluted, folded, or otherwise compressed or constricted
substantially transversely to the longitudinal axis of the
aerosol-generating article.
[0064] Advantageously, the aerosol-generating substrate comprises a
gathered textured sheet of homogenised tobacco material. As used
herein with reference to the invention, the term "textured sheet"
describes a sheet that has been crimped, embossed, debossed,
perforated or otherwise deformed.
[0065] Use of a textured sheet of homogenised tobacco material may
advantageously facilitate gathering of the sheet of homogenised
tobacco material to form the aerosol-generating substrate.
[0066] The aerosol-generating substrate may comprise a gathered
textured sheet of homogenised tobacco material comprising a
plurality of spaced-apart indentations, protrusions, perforations
or any combination thereof.
[0067] In certain preferred embodiments, the aerosol-generating
substrate comprises a gathered crimped sheet of homogenised tobacco
material. As used herein with reference to the invention, the term
"crimped sheet" describes a sheet having a plurality of
substantially parallel ridges or corrugations. Advantageously, when
the aerosol-generating article has been assembled, the
substantially parallel ridges or corrugations extend along or
parallel to the longitudinal axis of the aerosol-generating
article. This facilitates gathering of the crimped sheet of
homogenised tobacco material to form the aerosol-generating
substrate.
[0068] However, it will be appreciated that crimped sheets of
homogenised tobacco material for inclusion in the
aerosol-generating substrates of aerosol-generating articles
according to the invention may alternatively or in addition have a
plurality of substantially parallel ridges or corrugations that are
disposed at an acute or obtuse angle to the longitudinal axis of
the aerosol-generating article when the aerosol-generating article
has been assembled.
[0069] Sheets of homogenised tobacco material for use in the
invention may have a tobacco content of at least about 40 percent
by weight on a dry weight basis, more preferably of at least about
50 percent by weight on a dry weight basis more preferably at least
about 70 percent by weight on a dry weight basis and most
preferably at least about 90 percent by weight on a dry weight
basis.
[0070] Preferably, the sheets of homogenised tobacco material
comprise an aerosol former. The sheets of homogenised tobacco
material may comprise a single aerosol former. Alternatively, the
sheets of homogenised tobacco material may comprise a combination
of two or more aerosol formers.
[0071] Suitable aerosol-formers are known in the art and include,
but are not limited to: monohydric alcohols like menthol,
polyhydric alcohols, such as triethylene glycol, 1,3-butanediol and
glycerine; esters of polyhydric alcohols, such as glycerol mono-,
di- or triacetate; and aliphatic esters of mono-, di- or
polycarboxylic acids, such as dimethyl dodecanedioate, dimethyl
tetradecanedioate, erythritol, 1,3-butylene glycol, tetraethylene
glycol, triethyl citrate, propylene carbonate, Ethyl laurate,
triacetin, meso-erythritol, a diacetin mixture, a diethyl suberate,
triethyl citrate, benzyl benzoate, benzyl phenyl acetate, ethyl
vanillate, tributyrin, lauryl acetate, lauric acid, myristic acid,
and propylene glycol.
[0072] Preferably, the sheets of homogenised tobacco material have
an aerosol former content of greater than 5 percent on a dry weight
basis.
[0073] The sheets of homogenised tobacco material may have an
aerosol former content of between approximately 5 percent and
approximately 30 percent on a dry weight basis. In a preferred
embodiment, the sheets of homogenised tobacco material have an
aerosol former content of approximately 20 percent on a dry weight
basis.
[0074] Sheets of homogenised tobacco material for use in the
invention may comprise one or more intrinsic binders, that is
tobacco endogenous binders, one or more extrinsic binders, that is
tobacco exogenous binders, or a combination thereof to help
agglomerate the particulate tobacco. Alternatively, or in addition,
sheets of homogenised tobacco material for use in the
aerosol-generating substrate may comprise other additives
including, but not limited to, tobacco and non-tobacco fibres,
aerosol-formers, humectants, plasticisers, flavourants, fillers,
aqueous and non-aqueous solvents and combinations thereof.
[0075] Suitable extrinsic binders for inclusion in sheets of
homogenised tobacco material for use in the invention are known in
the art and include, but are not limited to: gums such as, for
example, guar gum, xanthan gum, arabic gum and locust bean gum;
cellulosic binders such as, for example, hydroxypropyl cellulose,
carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose
and ethyl cellulose; polysaccharides such as, for example,
starches, organic acids, such as alginic acid, conjugate base salts
of organic acids, such as sodium-alginate, agar and pectins; and
combinations thereof.
[0076] Suitable non-tobacco fibres for inclusion in sheets of
homogenised tobacco material for use in the aerosol-generating
substrate are known in the art and include, but are not limited to:
cellulose fibers; soft-wood fibres; hard-wood fibres; jute fibres
and combinations thereof. Prior to inclusion in sheets of
homogenised tobacco material for use in the aerosol-generating
substrate, non-tobacco fibres may be treated by suitable processes
known in the art including, but not limited to: mechanical pulping;
refining; chemical pulping; bleaching; sulfate pulping; and
combinations thereof.
[0077] Sheets of homogenised tobacco for use in the invention
preferably have a width of between about 70 mm and about 250 mm,
for example between about 120 mm and about 160 mm. Preferably, the
thickness of the sheets of homogenised tobacco material is between
about 50 micrometres and about 300 micrometres, more preferably
between about 150 micrometres and about 250 micrometres.
[0078] Sheets of homogenised tobacco for use in the
aerosol-generating article of the present invention may be made by
methods known in the art, for example the methods disclosed in
International patent application WO-A-2012/164009 A2.
[0079] In a preferred embodiment, sheets of homogenised tobacco
material for use in the aerosol-generating article are formed from
a slurry comprising particulate tobacco, guar gum, cellulose fibres
and glycerine by a casting process.
[0080] As an alternative to the use of a gathered sheet of
homogenised tobacco material, as described above, the
aerosol-generating substrate may be formed of a plurality of strips
or shreds of a sheet of homogenised tobacco material. For example,
the aerosol-generating substrate may be formed of a plurality of
shreds of homogenised tobacco material that are aligned in the
longitudinal direction and have been brought together and wrapped
to form a rod of aerosol-generating substrate.
[0081] The shreds of homogenised tobacco material preferably have a
length of between about 10 millimetres and about 20 millimetres,
more preferably between about 12 millimetres and about 18
millimetres, more preferably between about 14 millimetres and about
16 millimetres, more preferably about 15 millimetres. Alternatively
or in addition, the shreds of homogenised tobacco material
preferably have a width of between about 0.4 millimetres and about
0.8 millimetres.
[0082] Preferably, the density of the sheet of homogenised tobacco
material from which the shreds are formed is between about 500 and
about 1500 milligrams per cubic centimetre, more preferably between
about 800 and about 1200 milligrams per cubic centimetre, more
preferably between about 900 and about 1100 milligrams per cubic
centimetre, and most preferably between about 900 and about 970
milligrams per cubic centimetre.
[0083] Preferably, the bulk density of the shreds of homogenised
tobacco material within the aerosol-generating substrate is between
about 0.4 grams per cubic centimetre and about 0.8 grams per cubic
centimetre, preferably between about 0.5 grams per cubic centimetre
and about 0.7 grams per cubic centimetre and most preferably
between about 0.65 grams per cubic centimetre and about 0.67 grams
per cubic centimetre.
[0084] As described above, the homogenised tobacco material may be
formed by the casting of a slurry. Alternatively, the homogenised
tobacco material may be formed by another suitable method, such as
for example, an extrusion method.
[0085] As described above, the aerosol-generating substrate
comprises a rod of the homogenised tobacco material circumscribed
by a wrapper, wherein the wrapper is provided around and in contact
with the homogenised tobacco material and incorporates the heat
control element. The wrapper may be formed from any suitable sheet
material that is capable of being wrapped around homogenised
tobacco material to form an aerosol-generating substrate. The
wrapper may be porous or non-porous. Preferably, the wrapper is a
paper wrapper but the wrapper may alternatively be non-paper.
[0086] The rod of aerosol-generating substrate preferably has an
external diameter that is approximately equal to the external
diameter of the aerosol-generating article.
[0087] Preferably, the rod of aerosol-generating substrate has an
external diameter of at least 5 millimetres. The rod of
aerosol-generating substrate may have an external diameter of
between about 5 millimetres and about 12 millimetres, for example
of between about 5 millimetres and about 10 millimetres or of
between about 6 millimetres and about 8 millimetres. In a preferred
embodiment, the rod of aerosol-generating substrate has an external
diameter of 7.2 millimetres, to within 10 percent.
[0088] The rod of aerosol-generating substrate may have a length of
between about 7 millimetres and about 15 mm. In one embodiment, the
rod of aerosol-generating substrate may have a length of about 10
millimetres. In a preferred embodiment, the rod of
aerosol-generating substrate has a length of about 12
millimetres.
[0089] Preferably, the rod of aerosol-generating substrate has a
substantially uniform cross-section along the length of the rod.
Particularly preferably, the rod of aerosol-generating substrate
has a substantially circular cross-section.
[0090] The aerosol-generating articles according to the invention
preferably comprise one or more elements in addition to the rod of
aerosol-generating substrate and the heat control component. For
example, aerosol-generating articles according to the invention may
further comprise at least one of: a mouthpiece, an aerosol-cooling
element and a support element such as a hollow acetate tube. For
example, in one preferred embodiment, an aerosol-generating article
comprises, in linear sequential arrangement, a rod of
aerosol-generating substrate as described above, a support element
located immediately downstream of the aerosol-generating substrate,
an aerosol-cooling element located downstream of the support
element, and an outer wrapper circumscribing the rod, the support
element and the aerosol-cooling element.
[0091] Aerosol-generating systems according to the present
invention comprise an aerosol-generating article as described in
detail above in combination with an aerosol-generating device which
is adapted to receive the upstream end of the aerosol-generating
article during smoking. The aerosol-generating device comprises a
heating element which is configured to heat the aerosol-generating
substrate in order to generate an aerosol during use. Preferably,
the heating element is adapted to penetrate the aerosol-generating
substrate when the aerosol-generating article is inserted into the
aerosol-generating device. For example, the heating element is
preferably in the form of a heater blade.
[0092] The heating element is controlled during use to operate with
a defined operating temperature range, below a maximum operating
temperature. The heat control element of the aerosol-generating
article is adapted such that the shrink temperature of the
heat-shrinkable material forming the one or more circumferential
bands of the heat control element will not be reached during normal
use of the aerosol-generating article in the aerosol-generating
device with the heating element operating below the maximum
operating temperature. This ensures that when the
aerosol-generating article and aerosol-generating device are used
together, the heat control element will not be activated during
normal use.
[0093] Preferably, the aerosol-generating device additionally
comprises a housing, an electrical power supply connected to the
heating element and a control element configured to control the
supply of power from the power supply to the heating element.
[0094] Suitable aerosol-generating devices for use in the
aerosol-generating system of the present invention are described in
WO-A-2013/098405.
[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.
* * * * *