Note: Descriptions are shown in the official language in which they were submitted.
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ELECTRICALLY HEATED CIGARETTE INCLUDING CONTROLLED-
RELEASE FLAVORING
BACKGROUND
[0001 ] Traditional cigarettes are smoked by lighting an end of a wrapped
tobacco rod
and drawing air predominately through the lit end by suction at a mouthpiece
end of
the cigarette. Traditional cigarettes deliver smoke as a result of combustion,
during
which tobacco is combusted at temperatures that typically exceed 800°
C.
during a puff. The heat of combustion releases various gaseous combustion
products
and distillates from the tobacco. As these gaseous products are drawn through
the
cigarette, they cool and condense to form an aerosol, which provides the
flavors and
aromas associated with smoking.
[0002] Traditional cigarettes produce sidestream smoke during smoldering
between
puffs. Once lit, they normally are fully consumed or discarded. Relighting a
traditional cigarette is possible, but is not desirable for subjunctive
reasons including
flavor, taste and odor.
[0003] An alternative to the more traditional cigarette is the electrically
heated
cigarette used in electrical smoking systems. As compared to traditional
cigarettes,
electrical smoking systems significantly reduce sidestream smoke, and also
permit
smokers to suspend and reinitiate smoking as desired. Exemplary electrical
smoking
systems are disclosed in commonly-assigned U.S. Pat. Nos. 6,026,820;
5,988,176;
5,915,387; 5,692,526; 5,692,525; 5,666,976; 5,499,636; and 5,388,594.
Electrical
smoking systems include an electrically powered lighter and an electrically
heated
cigarette, which is constructed to cooperate with the lighter. It is desirable
that
electrical smoking systems be capable of delivering smoke in a
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manner similar to the smoker's experiences with traditional cigarettes, such
as by
providing an immediacy response (smoke delivery occurring immediately upon
draw), a desired level of delivery (that correlates with FTC tar level), a
desired
resistance to draw (RTD), as well as puff-to-puff and cigarette-to-cigarette
consistency.
[0004] Volatile flavorings have been incorporated in traditional cigarettes to
add
flavors and aromas to mainstream and sidestream tobacco smoke. See, for
example, U.S. Patents Nos. 3,006,347; 3,236,244; 3,344,796; 3,426,011;
3,972,335; 4,715,390; 5,137,034; 5,144,964; and 6,325,859, and commonly-
owned International Publication No. WO 01/80671. The added flavorings are
desirably volatilized when the cigarette is smoked. However, volatile
flavorings
tend to migrate in the cigarette to other components and possibly through the
entire
cigarette. Volatile flavorings can be lost from cigarettes during storage and
distribution at ordinary conditions prior to smoking of the cigarettes. The
degree
of migration of volatile flavorings in cigarettes depends on different
factors,
including the flavoring's vapor pressure, the solubility of the flavoring in
other
components of the cigarette, and temperature and humidity conditions. In
addition, a large portion of the added flavoring can be lost to the side
stream
smoke in traditional cigarettes.
[0005] Flavorings that have been incorporated in traditional cigarettes also
can
chemically and/or physically deteriorate by contacting and/or reacting with
other
components of the cigarette, as well as with the environment. For example,
activated carbon has been incorporated in traditional cigarettes to remove gas-
phase constituents from mainstream smoke. However, flavorings that have been
incorporated in the cigarettes along with the activated carbon have been
adsorbed
by the activated carbon, clogging pores of the activated carbon and
consequently
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deactivating the activated carbon, thereby diminishing its ability to filter
tobacco
smoke.
[0006] For the foregoing reasons, flavorings that have been incorporated in
traditional cigarettes have not been totally satisfactorily delivered to the
smoker.
Consequently, the flavorings incorporated in some traditional cigarettes have
not
satisfactorily provided the desired taste effect to the smoker and the
flavorings'
desired value to the subjective quality of the cigarette has been less than
desired.
Due to the flavoring loss, the uniformity of flavored cigarettes has not been
totally
satisfactory. In addition, the sorption of flavorings by sorbents in the
cigarettes has
deactivated the sorbents and thereby reduced their ability to remove gas phase
constituents from tobacco smoke.
SUMMARY
[0007] In view of the above-described problems that have been encountered in
some traditional cigarettes including flavorings and those also including
sorbents,
an electrically heated cigarette is provided, which includes a sorbent and a
controlled-release flavoring. In a preferred embodiment, the electrically
heated
cigarette comprises a sorbent and a flavoring incorporated in the cigarette in
a
form that preferably minimizes release and migration of the flavoring in the
cigarette prior to smoking, for example, at ambient conditions, and thus
preferably
minimizes deactivation of the sorbent by the flavoring. In addition, the
flavoring
preferably is released in the cigarette in a controlled manner during smoking.
Consequently, the flavoring preferably enhances subjective characteristics of
the
cigarette while the sorbent maintains its ability to remove gas-phase
constituents
from mainstream smoke.
[0008] A preferred embodiment of the electrically heated cigarette comprises
at
least one sorbent and a flavoring-release additive including one or more
flavorings.
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The flavoring is releasable in the cigarette upon the flavoring-release
additive
being heated to at least a minimum temperature, which occurs during smoking of
the cigarette.
[0009] The flavoring-release additive can be incorporated in various forms in
the
electrically heated cigarette. In one preferred embodiment, the flavoring-
release
additive comprises beads. In another preferred embodiment, the flavoring-
release
additive is a film. In yet another preferred embodiment, the flavoring-release
additive is an inclusion complex including a selected host molecule, and the
flavoring as a guest molecule in the inclusion complex.
[0010] In another preferred embodiment, two or more different flavoring-
release
additives having different flavoring release temperatures are located at
different
locations in an electrically heated cigarette that reach different
temperatures from
each other. The flavoring-release additives can be located at locations in the
electrically heated cigarette that reach the flavoring release temperature for
those
flavoring-release additives. Accordingly, the flavoring-release additive can
provide efficient, controlled release of the flavoring during smoking.
[0011] The electrically heated cigarette can comprise various sorbents. By
providing the flavoring in the flavoring-release additive, which preferably
minimizes release and/or migration of the flavoring until the flavoring-
release
additive reaches the flavoring release temperature, the flavoring is
preferably
substantially prevented from being sorbed by, and thus deactivating, the
sorbent,
thereby not adversely affecting the sorbent's ability to remove selected gas-
phase
constituents from mainstream tobacco smoke. In addition, because the flavoring
is
temperature released in the cigarette, it can be effectively delivered to a
smoker in
a controlled manner during puff cycles of the cigarette.
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[0012] A preferred embodiment of an electrical smoking system comprises a
lighter and at least one electrically heated cigarette including at least one
sorbent
and a flavoring-release additive.
[0013] A preferred embodiment of a method of making an electrically heated
cigarette comprises incorporating a sorbent and a flavoring-release additive
into an
electrically heated cigarette.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 illustrates a preferred embodiment of an electrically heated
cigarette for use in an electrical smoking system with the cigarette in a
partially
unassembled condition.
[0015] FIG. 2 illustrates the electrically heated cigarette shown in FIG. 1 in
the
assembled condition with one end of the cigarette contacting a stop piece of
an
electrically operated lighter of the electrical smoking system.
[0016] FIG. 3 illustrates another preferred embodiment of an electrically
heated
cigarette for use in an electrical smoking system with the cigarette in a
partially
unassembled condition.
[0017] FIG. 4 illustrates a preferred embodiment of an electrical smoking
system with an electrically heated cigarette inserted into the electrically
operated
lighter.
[0018] FIG. 5 illustrates the electrical smoking system shown in FIG. 4 with
the
cigarette withdrawn from the lighter.
[0019] FIG. 6 illustrates a heater fixture of the electrical smoking system.
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DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0020] An electrically heated cigarette includes one or more sorbents and at
least
one flavoring for affecting flavor, taste, and/or aroma of tobacco smoke. In a
preferred embodiment, the flavoring is incorporated in the cigarette in a
flavoring-
release additive, which preferably minimizes the release and/or migration of
the
flavoring in the cigarette prior to smoking. Preferably, the flavoring is
released
from the flavoring-release additive in a controlled manner during smoking of
the
cigarette. The flavoring-release additive enables the flavoring to enhance
subjective characteristics of the cigarette while avoiding an adverse impact
on the
effectiveness of the sorbent in removing selected gas-phase constituents from
mainstream smoke.
[0021] In a preferred embodiment of the electrically heated cigarette, the
flavoring is released in the cigarette upon the flavoring-release additive
being
heated to at least a minimum temperature (flavoring release temperature),
which
occurs when a smoker draws mainstream smoke through the cigarette.
[0022] It has been determined that different regions of the electrically
heated
cigarette reach different temperatures when a smoker draws on the cigarette.
In a
preferred embodiment, different flavoring-release additives are selectively
disposed at two or more locations in the electrically heated cigarette that
respectively reach at least the minimum temperature at which the flavoring is
released from the flavoring-release additive disposed at that location. By
selectively locating one or more flavoring-release additives in the cigarette,
the
cigarette can provide efficient, controlled release of the flavoring during
smoking.
[0023] The flavoring-release additive can have various constructions and
compositions and can be located at one or more locations, and/or incorporated
in
one or more components of the electrically heated cigarette. The flavoring-
release
additives can be designed to have different associated flavoring release
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temperatures. Accordingly, the flavoring-release additives can be incorporated
in
the electrically heated cigarette at locations that are most suitable for
providing
efficient release of the flavoring from the particular flavoring-release
additive.
[0024] The electrically heated cigarette can comprise one or more sorbents
capable of removing selected gas-phase constituents from mainstream smoke. By
providing the flavoring in the flavoring-release additive that preferably
minimizes
the release and/or migration of the flavoring in the cigarette until the
flavoring-
release additive reaches at least the minimum temperature, the flavoring is
preferably substantially prevented from deactivating the sorbent. Thus, the
ability
of the sorbent to remove selected gas-phase constituents from mainstream
tobacco
smoke can be maintained. Preferably, the flavoring-release additive enables
the
flavoring to be effectively delivered to a smoker in a controlled manner.
[0025] As used herein, the term "sorption" denotes filtration by adsorption
and/or absorption. Sorption is intended to encompass interactions on the outer
surface of the sorbent, as well as interactions within the pores and channels
of the
sorbent. In other words, a "sorbent" is a substance that has the ability to
condense
or hold molecules of other substances on its surface, and/or the ability to
take up
other substances, i.e., through penetration of the other substances into its
inner
structure, or into its pores. The term "sorbent" as used herein refers to
either an
adsorbent, an absorbent, or a substance that can function as both an adsorbent
and
an absorbent.
[0026] As used herein, the term "remove" refers to adsorption and/or
absorption
of at least some portion of a component of mainstream tobacco smoke.
[0027] The term "mainstream smoke" includes the mixture of gases passing
down the tobacco rod and issuing through the filter end, i.e., the amount of
smoke
issuing or drawn from the mouth end of a cigarette during smoking of the
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cigarette. The mainstream smoke contains air that is drawn in through the
heated
region of the cigarette and through the paper wrapper.
[0028] The term "molecular sieve" as used herein refers to a porous structure
comprised of an inorganic material and/or organic material. Molecular sieves
include natural and synthetic materials. Molecular sieves can sorb molecules
of
certain dimensions, while rejecting molecules having larger dimensions.
[0029] FIGS. 1 and 2 illustrate a preferred embodiment of the electrically
heated
cigarette 23. However, it should be understood that the electrically heated
cigarette can have other configurations suitable for smoking in an
electrically
powered lighter. The electrically heated cigarette 23 comprises a tobacco rod
60
and a filter tipping 62 joined together by tipping paper 64. The tobacco rod
60
preferably includes a tobacco web or "mat" 66 folded into a tubular form about
a
free-flow filter 74 at one end and a tobacco plug 80 at the other end.
[0030] An over wrap 71 surrounds the tobacco-containing mat 66 and is held
together along a longitudinal seam. The over wrap 71 retains the mat 66 in a
wrapped condition about the free-flow filter 74 and tobacco plug 80.
[0031] The mat 66 preferably comprises a base web 68 and a layer of tobacco
material 70. The tobacco material 70 can be located along the inside surface
or the
outside surface of the base web 68. At the tipped end of the tobacco rod 60,
the
mat 66 and the over wrap 71 are wrapped about the free-flow filter plug 74.
Preferably, the tobacco plug 80 comprises a relatively short tobacco column 82
of
cut filler tobacco, which is retained by a surrounding inner wrap 84.
[0032] A void 90 is between the free-flow filter 74 and the tobacco plug 80.
The void 90 is an unfilled portion of the tobacco rod 60 and is in fluid
communication with the tipping 62 through the free flow filter 74.
[0033] The tipping 62 preferably comprises a free-flow filter 92 located
adjacent
the tobacco rod 60 and a mouthpiece filter plug 94 at the distal end of the
tipping
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62 from the tobacco rod 60. Preferably, the free-flow filter 92 is tubular and
transmits air with very low pressure drop. The mouthpiece filter plug 94
closes
off the free end of the tipping 62.
[0034] The cigarette 23 optionally includes at least one row of perforations
12
adjacent the free end 15 of the cigarette 23. The perforations can be formed
as
slits 17, which preferably extend through the over wrap 71, the mat 66 and the
inner wrap 84.
[0035] To further improve delivery, at least one additional row of
perforations
14 comprising slits 17 can optionally be formed at a location along the
tobacco
plug 80. The perforations 12 or 14 may comprise a single row or a dual row of
slits 17. The number and extent of the slits 17 can be selected to control the
resistance to draw (RTD) along the side walls of the cigarettes 23 and the
delivery.
[0036] Optional holes 16 provided in the mat 66 are covered by the over wrap
71. The perforations 12, 14 can be used to approximate desired delivery levels
for
the cigarette 23, with the holes 16 being used to adjust delivery with a
lesser effect
on the RTD.
[0037] The cigarette 23 preferably has a substantially constant diameter along
its
length. The diameter of the cigarette 23, like more traditional cigarettes, is
preferably between about 7.5 mm to 8.5 mm so that the electrical smoking
system
21 provides a smoker with a familiar "mouth feel" during smoking.
[0038] The tobacco column 82 preferably comprises cut filler of a typical
blend
of tobaccos, such as blends comprising bright, Burley, and Oriental tobaccos
together with, optionally, reconstituted tobaccos and other blend components,
including traditional cigarette flavors.
[0039] The free-flow filter 92 and the mouthpiece filter plug 94 are
preferably
joined together as a combined plug with a plug wrap 101. The plug wrap 101 is
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preferably a porous, low-weight plug wrap. The combined plug is attached to
the
tobacco rod 60 by the tipping paper 64.
[0040] As described above, the electrically heated cigarette 23 can comprise
one or
more sorbents that remove gas-phase constituents of tobacco smoke. The sorbent
can
comprise one or more porous materials through which tobacco smoke can flow. In
a
preferred embodiment, the sorbent is activated carbon. For example, the
sorbent can
comprise activated carbon granules located in a void in the filter, or
activated carbon
particles loaded on fibrous material or paper. The activated carbon can be in
various
forms including particles, fibers, beads, and the like. The activated carbon
can have
different porosity characteristics, such as a selected pore size and total
pore volume.
[0041 ] In another preferred embodiment, the sorbent is one or more suitable
molecular sieve sorbent materials. Molecular sieve sorbents that may be used
in the
electrically heated cigarette 23 include, but are not limited to, one or more
of the
zeolites, mesoporous silicates, alumino phosphates, mesoporous
aluminosilicates, and
other related porous materials, such as mixed oxide gels, which may optionally
further
comprise inorganic or organic ions and/or metals. See, for example, commonly-
owned International Publication No. WO 01/80973.
[0042] In a preferred embodiment, the sorbent is one or more zeolites.
Zeolites
include crystalline aluminosilicates having pores, such as channels and/or
cavities of
uniform, molecular sized dimensions. There are many known unique zeolite
structures
having different sized and shaped pores, which can significantly affect the
properties
of these materials with regard to sorption and separation processes. Molecules
can be
separated by zeolites by size and shape effects related to the possible
orientation of
the molecules in the pores, and/or by differences in strength of sorption. One
or more
zeolites having pores larger than one or more selected
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gas phase components of a gas that is desired to be filtered can be used in
the
electrically heated cigarette 23, such that only selected molecules that are
small
enough to pass through the pores of the molecular sieve material are able to
enter
the cavities and be sorbed on the zeolite.
[0043] The zeolite can be, but is not limited to, one or more of zeolite A;
zeolite
X; zeolite Y; zeolite K-G; zeolite ZK-5; zeolite BETA; zeolite ZK-4 and
zeolite
ZSM-5. In a preferred embodiment, zeolite ZSM-5 and/or zeolite BETA is used.
ZSM-5 is in the MFI structural classification family and represented by the
crystal
chemical data [Nan(Al Si96-nO192) -16H20, with n < 27, orthorhombic, Pnma],
while zeolite BETA is in the BEA structural classification family and
represented
by the crystal chemical data [Na7(Al7Si57O128) tetragonal, P4122]. These two
zeolites are thermally stable at temperatures up to about 800 C, allowing them
to
be incorporated in cigarette filters and/or the tobacco rod of the
electrically heated
cigarette 23.
[0044] In another preferred embodiment, the sorbent incorporated in the
electrically heated cigarette 23 has a composite composition. In such
embodiment,
the sorbent comprises, for example, activated carbon and one or more molecular
sieve materials, such as those described above. For example, sorbent fibers
can be
impregnated with at least one sorbent.
[0045] Microporous, mesoporous, and/or macroporous molecular sieves may be
used in the electrically heated cigarette 23, depending on the selected
component(s)
desired to be removed from mainstream tobacco smoke.
[0046] The sorbent can be incorporated in one or more locations of the
electrically heated cigarette 23. For example, the sorbent can placed in the
passageway of the tubular free-flow filter 74, in the free-flow filter 92,
and/or in
the void space 90. The sorbent can additionally or alternatively be
incorporated in
the tobacco plug 80.
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[0047] FIG. 3 shows another preferred embodiment of an electrically heated
cigarette 23 including a filter 150. The filter 150 comprises a sorbent in the
form
of oriented fibers 152 and a sleeve 154, such as paper, surrounding the
fibers.
The sorbent can be, for example, one or more of activated carbon, silica gel,
zeolite, and other molecular sieves in fibrous forms. The sorbents can be
surface
modified materials, for example, surface modified silica gel, such as amino
propyl
silyl (APS) silica gel. Sorbent mixtures can provide different filtration
characteristics to achieve a targeted filtered mainstream smoke composition.
[0048] Alternatively, the fibers 152 can comprise one or more sorbent
materials,
such as carbon, silica, zeolite and the like, impregnated in microcavity
fibers, such
as TRIADTM micro-cavity fiber, as disclosed in commonly-owned International
Publication No. WO 01/80973. In a preferred embodiment, the fibers are shaped
microcavity fibers impregnated with particles of one or more sorbent
materials, or
alternatively continuous activated carbon fibers. The fibers preferably have a
diameter of from about 10 microns to about 100 microns. The fibers can have a
length of from about 10 microns to about 200 microns, for example.
[0049] In another preferred embodiment, the fibers are bundles of non-
continuous fibers, which are preferably oriented parallel to the direction of
mainstream smoke flow through the electrically heated cigarette.
[0050] The filters 150 including fibers 152 can be formed, for example, by
stretching a bundle of non-crimped sorbent fiber material, preferably having a
controlled total and per filament denier, through a pre-formed or in-situ
formed
sleeve 154 during the filter making process. The formed filter can be sized by
cutting to a desired length. For example, the filters can have a length of
from
about 5 mm to about 30 mm.
[0051] The filter 150 including fibers 152 can be incorporated in the
electrically
heated cigarette at one or more desired locations. Referring also to FIGS. 1
and 2,
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in a preferred embodiment, the filter 150 can be substituted for the entire
free-flow
filter 92. In another preferred embodiment, the free-flow filter 150 can be
substituted for a portion of the free-flow filter 92. The filter 150 can be in
contact
with (i.e., abut) the free-flow filter 74, positioned between the free-flow
filter 74
and the mouthpiece filter plug 94, or in contact with (i.e., abut) the
mouthpiece
filter plug 94. The filter 150 preferably has a diameter substantially equal
to that
of the outer diameter of the free-flow filter 92 to minimize by-pass of smoke
during the filtration process.
[0052] The fibrous sorbents preferably have a high loft with a suitable
packing
density and fiber length such that parallel pathways are created between
fibers.
Such structure can effectively remove significant amounts of selected gas-
phase
constituents, such as formaldehyde and/or acrolein, while preferably removing
only a minimal amount of particulate matter from the smoke, thereby achieving
a
significant reduction of the selected gas-phase constituents, while not
significantly
affecting the total particulate matter (TPM) in the gas. A sufficiently low
packing
density and a sufficiently short fiber length are preferred to achieve such
filtration
performance.
[0053] The amount of sorbent used in preferred embodiments of the electrically
heated cigarette 23 depends on the amount of selected gas-phase constituents
in the
tobacco smoke and the amount of the constituents that is desired to be removed
from the tobacco smoke.
[0054] As described above, the electrically heated cigarette 23 also comprises
at
least one flavoring-release additive. The flavoring can be, for example, one
or
more flavorings including, but not limited to, menthol, mint, such as
peppermint
and spearmint, chocolate, licorice, citrus and other fruit flavors, gamma
octalactone, vanillin, ethyl vanillin, breath freshener flavors, spice
flavors, such as
cinnamon, methyl salicylate, linalool, bergamot oil, geranium oil, lemon oil,
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ginger oil, and tobacco flavor. In a preferred embodiment, the flavoring is
menthol and optionally at least one mint flavoring.
[0055] As described above, the flavoring-release additive can have different
structures and compositions in the electrically heated cigarette. In one
preferred
embodiment, the flavoring-release additive is in the form of beads. The beads
preferably encapsulate the flavoring and provide for controlled release of the
flavoring in the cigarette during puff cycles.
[0056] The beads preferably comprise at least one encapsulating material and
at
least one flavoring. The encapsulating material preferably comprises a binder,
which can be, for example, one or more of palm oil, konjac gum, xylitol, zein,
hydroxypropylcellulose, sorbitol, maltitol, and hydroxypropylmethylcellulose.
Other materials known in the art that can improve the bead-forming
characteristics
of the encapsulating material or enhance its stability can optionally also be
added
in the beads. In a preferred embodiment, the beads have a substantially
homogenous composition in which flavoring is substantially uniformly
distributed.
By such structure, the flavoring can be released from the beads in a more
uniform
manner during smoking.
[0057] Depending on the composition of the beads, the minimum temperature at
which the beads release the flavoring can be adjusted. Beads comprising one or
more of the above-described binders preferably have a minimum temperature at
which the flavoring is released of at least about 40 C, such as about 40 C to
about
150 C. The beads protect the flavoring from exposure to undesired substances
in
the atmosphere (e.g., ambient air, inside a package) and undesired substances
in
the cigarette, and preferably minimize release and/or migration of the
flavoring
until the flavoring-release additive is heated to a sufficiently high
temperature
during smoking of the cigarette. Consequently, the flavoring is preferably
substantially prevented from migrating in the cigarette, reacting with other
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substances in the cigarette or with the environment, and deactivating sorbent
present
in the cigarette.
[0058] The beads can have any desired shape, such as different regular and
irregular
shapes, including round, square, rectangular, oval, other polygonal shapes,
cylindrical,
fibrous, and the like. The beads can have various sizes. Preferably, the beads
are
microbeads having a maximum particle size of less than about 25 microns, and
more
preferably less than about 1 micron. Decreasing the size of the beads can
provide a
more homogenous and controlled release of flavoring by providing increased
surface
area of the beads.
[0059] The beads can be manufactured by any suitable process that produces
beads
having the desired structure, composition, and size. For example, the beads
can be
manufactured by extrusion, spray drying, coating, or other suitable processes.
In a
preferred embodiment, the beads are formed by forming a solution, dispersion
or
emulsion containing a binder, flavoring and optional additives to form beads,
which
can be isolated and dried. Processes for preparing beads containing an active
ingredient, such as a flavor, are disclosed in U.S. Pat. No. 6,325,859.
[0060] The electrically heated cigarette 23 preferably comprises an amount of
the
beads that provides a desired amount of the flavoring in the cigarette. In a
preferred
embodiment, the electrically heated cigarette comprises, based on the total
weight of
tobacco in the cigarette, up to about 20%, and more preferably about 10% to
about
15%, of the beads. For example, a cigarette containing 100 mg of tobacco
preferably
contains up to about 20 mg of beads. The beads can preferably comprise up to
about
20% of flavoring. The cigarette can comprise, for example, from about 1 mg to
about
15 mg of flavoring.
[0061] In a preferred embodiment, the beads are disposed in at least one
location in
the electrically heated cigarette 23 that reaches at least the minimum
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temperature at which the flavoring is released from the beads and into the
cigarette
during smoking. For example, the beads can be disposed in the tobacco rod 60,
in
the void 90 between the tobacco plug 80 and the free-flow filter 74, on one or
more surfaces of the free-flow filter 74, on or in the mat 66, and/or on or in
the
inner wrap 84 surrounding the tobacco plug 80.
[0062] In another preferred embodiment, different bead compositions having
two or more different minimum flavoring-release temperatures can be
incorporated
at two or more locations in an electrically heated cigarette that reaches
different
temperatures at such locations during smoking. For example, beads having a
first
flavoring release temperature can be located at a first location in the
cigarette that
reaches the first flavoring-release temperature, and beads having a second
flavoring-release temperature higher than the first flavoring-release
temperature
can be located at a second location in the cigarette that reaches the second
flavoring-release temperature. For example, the two flavoring release
temperatures can vary by up to about 100 C. For example, these two
temperatures can vary by up to about 10 C, 20 C, 30 C, 40 C, 50 C, 60 C,
70 C, 80 C, 90 C, or 100 C.
[0063] In another preferred embodiment, the flavoring-release additive
includes
a film. The film preferably encapsulates the flavoring and enables the
controlled
temperature release of the flavoring in the cigarette during smoking. In a
preferred embodiment, the film comprises by weight up to 20%, more preferably
about 10% to about 15%, of the flavoring. In a preferred embodiment, the film
encapsulates menthol and optionally also mint.
[0064] The film-type flavoring-release additive preferably comprises at least
one
encapsulating material and at least one flavoring. The encapsulating material
preferably comprises a binder, which can be, for example, one or more of
carraghenan, gelatin, agar, gellan gum, gum arabic, guar gum, xanthum gum, and
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pectin. Other materials known in the art that can improve the film-forming
characteristics of the encapsulating material or enhance its stability can
optionally
be added to the film. In a preferred embodiment, the film has a substantially
homogenous composition in which flavoring is substantially uniformly
distributed.
By such structure, the flavoring can be released from the film in a more
desired
manner during smoking. The film encapsulating material provides a barrier to
the
release of the flavoring.
[0065] Depending on the composition of the film, the minimum temperature at
which the film releases the flavoring can be adjusted/selected. A film
comprising
one or more of the above-described binders preferably has a minimum
temperature
at which the flavoring is released of at least about 50 C, such as up to about
120 C. The film protects the flavoring from exposure to undesired substances
in
the cigarette and atmosphere and substantially prevents the flavoring from
being
released until the film is heated to the flavoring release temperature during
smoking of the cigarette.
[0066] The film can be applied to one or more components of the electrically
heated cigarette as a liquid coating, which is dried to a film. The dimensions
of
the dried film are not limited. Preferably, the dried film has a maximum
thickness
of about 50 microns to about 150 microns, and more preferably about 75
microns.
[0067] The film can be manufactured by any suitable process that produces a
film having the desired structure, composition, and dimensions. For example,
the
film can be applied by a coating process, such as spray coating, a dipping
process,
electrostatic deposition, printing wheel application, gravure printing, ink
jet
application, and the like. In a preferred embodiment, an emulsion, suspension
or
slurry comprising the binder, flavoring, and optional additives is prepared
and
then applied as a coating to one or more selected surfaces of one or more
selected
components of the electrically heated cigarette. The coating is preferably
dried to
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remove water and/or other solvents and form a solid film having desired
dimensions. Exemplary processes that can be used to prepare the films are
described in U.S. Patents Nos. 3,006,347 and commonly-owned 4,715,390.
[0068] The electrically heated cigarette 23 preferably comprises an amount of
the film that releases a desired amount of the flavoring during smoking of the
cigarette. In a preferred embodiment, the electrically heated cigarette
comprises,
based on the total weight of tobacco in the cigarette to which the film is
applied, up to about 20%, and more preferably about 10% to about 15%, of the
film. For
example, if the film is applied to the mat, the weight of tobacco contained in
the
mat preferably is the weight basis for the amount of the film. If the film is
applied to the mat and to the tobacco plug, the total weight of tobacco
contained in
the mat and the tobacco plug preferably is the weight basis for the amount of
film applied in the cigarette. Preferably, the weight of tobacco contained in
the
mat is the
weight basis for the amount of film applied to the mat, and the weight of
tobacco
contained in the tobacco plug is the weight basis for the amount of film
applied to
the tobacco plug. In a preferred embodiment, the cigarette can comprise from
about 1 mg to about 15 mg of flavoring.
[0069] In a preferred embodiment, the film is disposed in at least one
location
in
the electrically heated cigarette 23 that reaches at least the flavoring
release
temperature. For example, the film can be disposed on the tobacco plug 80, on
the inner wrap 84 surrounding the tobacco plug 80, on the mat 66, and/or on
the
over wrap 71 surrounding the mat. When the film is disposed on the inner
wrap 84 and/or over wrap 71, the weight of the inner wrap 84 and/or over wrap
71 is
the weight basis for the amount of the film. In another preferred embodiment,
the film can be preformed, shredded and incorporated in the tobacco plug 80,
and/or other selected locations that reach the flavoring release temperature.
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[0070] In another preferred embodiment, different flavored films having two or
more
different minimum flavoring-release temperatures can be incorporated at
different
locations in an electrically heated cigarette, where during smoking of the
cigarette, the
temperatures at the different locations exceed the minimum release
temperatures of
the different films.
[0071 ] In another preferred embodiment, the flavoring-release additive is an
inclusion
complex. The inclusion complex comprises a "host molecule," and the flavoring
is the
"guest molecule" in the inclusion complex. The inclusion complex provides for
controlled release of the flavoring in the cigarette during smoking. In a
preferred
embodiment, the flavoring is a lipophilic organic flavoring, which preferably
concentrates within a hydrophobic cavity of the host molecule. Suitable
flavorings
include, but are not limited to, menthol, mint, such as peppermint and
spearmint,
chocolate, licorice, citrus and other fruit flavors, gamma octalactone,
vanillin, ethyl
vanillin, breath freshener flavors, spice flavors, such-as cinnamon, methyl
salicylate,
linalool, bergamot oil, geranium oil, lemon oil, ginger oil, and tobacco
flavor. In a
preferred embodiment, the flavoring includes vanillin and gamma octalactone.
In a
preferred embodiment, the inclusion complex comprises by weight up to about
20%,
more preferably from about 10% to about 15%, of the flavoring.
[0072] The host molecule of the inclusion complex is preferably a
cyclodextrin.
Cyclodextrins are cyclic oligosaccharides including glucopyranose subunits, as
described, for example, in U.S. Pat. No. 3,426,011 and commonly-owned U.S.
Pat.
No. 5,144,964. The inclusion complex is formed when a flavoring material is
mixed
with a selected cyclodextrin in solution. The flavoring resides inside the
cyclodextrin
ring structure. The cyclodextrins and flavoring are typically co-precipitated,
filtered,
and dried.
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[0073] Alpha-cyclodextrin, beta-cyclodextrin and gamma-cyclodextrin include
six, seven and eight glucopyranose subunits, respectively. In a preferred
embodiment, the inclusion complex comprises beta-cyclodextrin, which can
desirably accommodate a wide variety of guest molecules and is readily
available.
Beta-cyclodextrin has a ring structure of the linked subunits with a three-
dimensional o
torus configuration including a hydrophobic cavity with a 7.5 A
diameter and hydrophillic upper and lower edges.
[0074] The minimum temperature at which the inclusion complex comprising a
cyclodextrin releases the flavoring is preferably at least about 60 C, such as
from
about 60'C to about 125'C. By incorporating the flavoring in the inclusion
complex, the flavoring can be protected from exposure to undesired substances
in
the cigarette and the atmosphere release and/or migration of the,flavoring is
preferably minimized until the flavoring-release additive is heated to the
flavoring
release temperature during smoking of the cigarette.
[0075]' The inclusion complex is preferably in powder form. The powder
preferably has maximum size of less than about 200 microns.
[0076] The inclusion complex can be made by forming an aqueous solution of
beta-cyclodextrin and the flavoring. The inclusion complex can be- recovered
from
the solution in powder form. However, the solution can be applied directly to
one
or more selected locations of one or more components of the electrically
heated
cigarette by any suitable process. The inclusion complex powder can
alternatively
be used to form a solution or a suspension. The inclusion complex can be
applied
by a coating process, such as slurry coating, spraying, a dipping process,
electrostatic deposition, printing wheel application, gravure printing, ink
jet
application, and the like. In a preferred embodiment, a solution, suspension
or
slurry comprising the cyclodextrin and flavoring is prepared and applied as a
coating to selected surfaces of selected components of the electrically heated
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cigarette. Exemplary processes that can be used to apply the inclusion complex
in the
electrically heated cigarette are described in commonly-owned U.S. Pat. No.
5,144,964.
[0077] The electrically heated cigarette 23 preferably comprises an amount of
the
inclusion complex that provides a desired amount of the flavoring in the
cigarette. In a
preferred embodiment, the electrically heated cigarette comprises, based on
the
weight of the over wrap or mat, up to about 15%, and more preferably less than
about
8%, of the inclusion complex. For example, if the inclusion complex is applied
to the
mat, then the weight of the mat preferably is the weight basis for the amount
of the
inclusion complex applied to the mat. If the inclusion complex is applied to
the mat
and the over wrap, then the total weight of the mat and the over wrap
preferably is the
weight basis for the amount of the inclusion complex applied to the mat and
the over
wrap. The weight percent of the inclusion complex that is applied to the mat
and/or
over wrap can be the same or different. In a preferred embodiment, the
cigarette
comprises from about 1 mg to about 50 mg of flavoring.
[0078] In a preferred embodiment, the inclusion complex is disposed in at
least one
location in the electrically heated cigarette 23 that reaches at least the
minimum
temperature at which the flavoring is released from the inclusion complex in
the
cigarette during smoking. For example, the inclusion complex can be disposed
on the
inner wrap 84, mat 66, and/or the over wrap 71.
[0079] In another preferred embodiment, the electrically heated cigarette
comprises
two or more different types of flavoring-release additives, for example, a
bead and a
film and/or an inclusion complex, with each flavoring-release additive having
a
different flavoring release temperature. The different flavoring-release
additives can
be incorporated at two or more locations in the same electrically
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heated cigarette that reach different temperatures during smoking in order to
provide further controlled release of the flavoring during smoking.
[0080] FIGS. 4 and 5 illustrate a preferred embodiment of an electrical
smoking
system in which preferred embodiments of the electrically heated cigarette can
be
used. However, it should be understood that preferred embodiments of the
electrically heated cigarette can be used in electrical smoking systems having
other
constructions,. such as those having different electrically powered lighter
constructions. The electrical smoking system 21 includes an electrically
heated
cigarette 23 and a reusable lighter 25. The cigarette 23 is constructed to be
inserted into and removed from a cigarette receiver 27, which is open at a
front
end portion 29 of the lighter 25. Once the cigarette 23 is inserted, the
smoking
system 21 is used in a similar manner as a more traditional cigarette, but
without
lighting or smoldering of the cigarette 23. The cigarette 23 is discarded
after
smoking.
[0081] Preferably, each cigarette 23 provides a total of at least eight puffs
(puff
cycles) per smoke. However, the cigarette 23 can be constructed to provide a
lesser .or greater total number of available puffs... .
[0082] The lighter 25 includes a housing 31 having front and rear housing
portions 33 and 35, respectively. A power source 35a, such as one or more
batteries, is located within the rear housing portion 35 and supplies energy
to a
heater fixture 39. The heater fixture 39 includes a plurality of electrically
resistive, heating elements 37 (FIG. 6). The heating elements 37 are arranged
within the front housing portion 33 to glidingly receive the cigarette 23. A
stop
183 located in the heater fixture 39 defines a terminal end of the cigarette
receiver
27 (FIG. 2).
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[0083] Control circuitry 41 in the front housing portion 33 selectively
establishes electrical communication between the power source 35a and one or
more of the heating elements 37 during each puff cycle.
[0084] The rear housing portion 35 of the housing 31 is constructed to be
opened and closed to facilitate replacement of the power source 35a.
Preferably,
the front housing portion 33 is removably attached to the rear housing portion
35
by mechanical, engagement.
[0085] Referring to FIG. 5, in a preferred embodiment, the control circuitry
41
is activated by a puff-actuated sensor 45, which is sensitive to either
changes in
pressure or changes in the rate of air flow that occur upon initiation of a
draw on
the cigarette 23 by a smoker. The puff-actuated sensor 45 is preferably
located
within the, front housing portion 33 of the lighter 25 and communicates with a
space inside the heater fixture 39 via a port 45a extending through a side
wall
portion 182 of the heater fixture 39. Once actuated by the sensor 45, the
control
circuitry 41 directs electric current to an appropriate one of the heating
elements
37.
.[0086] In a preferred embodiment, .an. indicator 51 is provided at location
along the exterior of the lighter 25 to visually indicate the number of puffs
remaining in a cigarette 23, or other selected information. The indicator 51
preferably includes a liquid crystal display. In a preferred embodiment, the
indicator 51 displays a selected image when a cigarette detector 57 detects
the
presence of a cigarette in the heater fixture 39. The detector 57 can comprise
any
arrangement that senses the presence of an electrically heated cigarette. For
example, the detector can comprise an inductive coil 1102 adjacent the
cigarette
receiver 27 of the heater fixture 39 and electric leads 1104 that communicate
the
coil 1102 with an oscillator circuit within the control circuitry 41. In such
case,
the cigarette 23 can include a metallic element (not shown), which can affect
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inductance of the coil winding 1102 such that whenever 'a suitable cigarette
23 is
inserted into the receiver 27, the detector 57 generates a signal to the
circuitry 41
indicating the cigarette is present. The control circuitry 41 provides a
signal to the
indicator 51. When the cigarette 23 is removed from the lighter 25, the
cigarette
detector 57 no longer detects the presence of a cigarette 23 and the indicator
51 is
turned off.
[0087] The heater fixture 39 supports an inserted cigarette 23 in a fixed
relation
to the heating elements 37 such that the heating elements 37 are positioned
alongside the cigarette 23 at approximately the same location for each newly
inserted cigarette 23. In a preferred embodiment, the heater fixture 39
includes
eight mutually parallel heater elements 37, which are disposed concentrically
about
the axis of symmetry of the cigarette receiver 27. The location where each
heating
element 37 touches a fully inserted cigarette 23 is referred to herein as the
heater
footprint or char zone 42.
[0088] As shown in FIG. 6, the heating elements 37 preferably each include at
least first and second serpentine, elongate members 53a and 53b adjoined at a
tip
54. The heater portions 53a,. 53b. and 54. form a heater blade 120., . The
tips 54 are
adjacent the opening 55 of the cigarette receiver 27. The opposite ends 56a
and
56b of each heating element 37 are electrically connected to the opposite
poles of
the power source 35a as selectively established by the controller 41. An
electrical
pathway through each heating element 37 is established, respectively, through
a
terminal pin 104, a connection 121 between the pin 104 and a free end portion
56a
of one of the serpentine members 53a, through at least a portion of the tip 54
to
the other serpentine member 53b and its end portion 56b. Preferably, a
connection
ring 110 provides a common electrical connection to each of the end portions
56b.
In a preferred embodiment, the ring 110 is connected to the positive terminal
of
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the power source 35a through a connection 123 between the ring 110 and a pin
105.
[0089] Preferably, the heating elements 37 are individually energized by the
power source 35a under the control of the control circuitry 41 to heat the
cigarette
23 preferably eight times at spaced locations about the periphery of the
cigarette
23. The heating renders'eight puffs from the cigarette 23, as is commonly
achieved with the smoking of a more traditional cigarette. It may be preferred
to
activate more than one heating element simultaneously for one or more or all
of
the puffs.
[0090] , The heater fixture 39 includes an air inlet port 1200 through which
air is
drawn into the lighter. A pressure drop is induced upon the air entering the
lighter
such that the puff sensor 45 is operative to recognize initiation of a puff.
The
range of pressure drop induced is selected such that it is within the range of
pressure drop detectable by the pressure sensor 45.
[0091] The length of the tobacco plug 80 and its relative position along the
tobacco rod 60 is preferably selected based on the construction and location
of the
heating elements 37 of-the electrical smoking sysWm.21. When' a cigarette 23
is
properly positioned against a stop 182 (FIG. 2) within the lighter of the
electrical
smoking system, a portion of each heating element contacts the tobacco rod 60.
This region of contact is referred to as a heater footprint 95, which is that
region
of the tobacco rod 60 where the heating element 37 is expected to reach a
temperature high enough to allow smoking of the cigarette without combustion
of
the cigarette paper, mat or tobacco. The'heater foot print 95 can consistently
locate along the tobacco rod 60 at the same predetermined distance 96 from the
free end 78 of the tobacco rod 60 for every cigarette 23 that is fully
inserted into
the lighter 25.
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[0092] Preferably, the length of the tobacco plug 80 of the cigarette 23, the
length of the heater footprint 95, and the distance between the heater
footprint
95 and the stop 182 are selected such that the heater footprint 95 extends
beyond the tobacco plug 80 and superposes a portion of the void 91 by a
distance 98. The distance 98 is also referred to as the "heater-void overlap"
98.
The distance over which the remainder of the heater footprint 95 superposes
the tobacco plug 80 is referred to as the "heater-filler overlap" 99.
[0093] The length of the void 91, tobacco plug 80, and the distribution of the
perforation holes 263 may be adjusted to adjust the smoking characteristics of
the cigarette 23, including adjustments in its taste, draw and delivery. The
pattern of holes 263, the length of the void 90 and the amount of heater-
filler
overlap 99 (and heater-void overlap 98) may also be manipulated to adjust the
immediacy of response, to promote consistency in delivery.
[0094] Electrically heated cigarettes according to preferred embodiments can
provide advantages. By encapsulating one or more added flavorings,
especially volatile flavoring, the flavoring(s) can be retained in the
cigarette
until it is smoked. In addition, the flavouring is preferably temperature
released in a controlled manner during smoking, thereby providing the smoker
with an enhanced subjective characteristic of the cigarette. As the flavouring
can be retained in the flavoring-release additive until the cigarette is
smoked,
deactivation of the sorbent in the cigarette is preferably minimized.
Consequently, the sorbent maintains it ability to remove selected gas phase
constituents from mainstream smoke.
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