Note: Descriptions are shown in the official language in which they were submitted.
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1
ELECTRICALLY HEATED CIGARETTE INCLUDING
CONTROLLED-RELEASE FLAVORING
s [BLANK]
BACKGROUND
Traditional cigarettes are smoked by lighting an end of a wrapped
tobacco rod and drawing air predominately through the lit end by
is 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.
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.
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 US-A-6 026 820; US-A-5 988 176;
US-A-5 915 387; US-A-5 692 526; US-A-5 692 525; US-
A-5 666 976;
US-A-5 499, 636; and US-A-5 388 594.
Electrical smoking systems
include an electrically powered lighter and an electrically heated
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cigarette, which is constructed to cooperate with the lighter. It is
desirable that electrical smoking systems be capable of delivering
smoke in a manner similar to the smoker's experiences with traditional
cigarettes, such as by providing an immediacy response (smoke delivery
s 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.
Volatile flavorings have been incorporated in traditional
cigarettes to add flavors and aromas to mainstream and sidestream
lo tobacco smoke.
See, for example, US-A-3 006 347; US-A-3 236 244;
US-A-3 344 796; US-A-3 426 011; US-A-3 972 335;
US-A-4 715 390;
US-A-5 137 034; US-A-5 144 964; and US-A-6 325 859, and WO-A-01/80671.
The added flavorings are desirably volatilized when the cigarette is
smoked. However, volatile flavorings tend to migrate in the cigarette
15 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
20 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.
Flavorings that have been incorporated in traditional
25 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
30 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 deactivating the activated carbon,
thereby diminishing its ability to filter tobacco smoke.
For the foregoing reasons, flavorings that have been
35 incorporated in traditional cigarettes have not been totally
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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
s than desired. Due to the flavoring loss, the uniformity of flavored
cigarettes has not been totally satisfactory.
Ira 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
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
s 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
o 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
,s constituents from mainstream smoke.
A preferred embodiment of the electrically laeated cigarette
comprises at least one sorbent and a flavoring-release additive
including one or more flavorings. The flavoring is releasable in the
cigarette upon the flavoring-release additive being heated to at least
.o a minimum temperature, which occurs during smoking of the cigarette.
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
Is film.
In yet another preferred embodiment, the flavoring-release
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additive is an inclusion complex including a selected host molecule,
and the flavoring as a guest molecule in the inclusion complex.
In another preferred embodiment, two or more different
flavoring-release additives having different flavoring release
S 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
o flavoring-release additive can provide efficient, controlled release
of the flavoring during smoking.
The electrically heated cigarette can comi=ise various
sorbents.
By providing the flavoring in the flavoring-release
additive, which preferably minimizes release and/or migration of the
s 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 tobaccc> smoke.
In
o 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.
A preferred embodiment of an electrical smoking system
comprises a lighter and at least one electrically heated cigarette
's including at least one sorbent and a flavoring-release adclitive.
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.
Another embodiment relates to an electrically heated cigarette
lo having a flavoring-release additive in a tobacco mat, a sorbent in a
filter component and a tobacco plug free of flavoring-release
additive.
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BRIEF DESCRIPTION OF THE DRAWINGS
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.
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.
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.
FIG. 4 illustrates a preferred embodiment of an electrical
smoking system with an electrically heated cigarette inserted into the
electrically operated lighter.
FIG. 5 illustrates the electrical smoking system shown in FIG.
4 with the cigarette withdrawn from the lighter.
FIG. 6 illustrates a heater fixture of the electrical smoking
system.
FIG. 7 illustrates a second preferred embodiment of an electrically
heated cigarette for use in an electrical smoking system with the
cigarette in a partially unassembled condition.
FIG. 8 illustrates a third preferred embodiment of an electrically
heated cigarette for use in an electrical smoking system with the
cigarette in a partially unassembled condition.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
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
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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.
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
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release temperature) , which occurs when a smoker draws mainstream
smoke through the cigarette.
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
o selectively locating one or more flavoring-release additives in the
cigarette, the cigarette can provide efficient, controlled release of
the flavoring during smoking.
The flavoring-release additive can have various constructions
and compositions and can be located at one or more locations, and/or
.5 incorporated in one or more components of the electrically heated
cigarette.
The flavoring-release additives can be designed to have
different associated flavoring release temperatures. Accordingly, the
flavoring-release additives can be incorporated in the electrically
heated cigarette at locations that are most suitable for providing
m efficient release of the flavoring from the particular flavoring-
release additive.
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
25 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
m 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.
As used herein, the term "sorption" denotes filtration by
adsorption and/or absorption.
Sorption is intended to encompass
35 interactions on the outer surface of the sorbent, as well as
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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.
As used herein, the term "remove" refers to adsorption and/or
lo absorption of at least some portion of a component of mainstream
tobacco smoke.
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
is during smoking of the cigarette. The mainstream smoke contains air
that is drawn in through the heated region of the cigarette and
through the paper wrapper.
The term "molecular sieve" as used herein refers to a porous
structure comprised of an inorganic material and/or organic material.
20 Molecular sieves include natural and synthetic materials. Molecular
sieves can sorb molecules of certain dimensions, while rejecting
molecules having larger dimensions.
FIGS. 1 and 2 illustrate a preferred embodiment of the
electrically heated cigarette 23. However, it should be understood
25 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
30 tubular form about a free-flow filter 74 at one end and a tobacco plug
80 at the other end.
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
35 tobacco plug 80.
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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.
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
lo is in fluid communication with the tipping 62 through the free flow
filter 74.
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 62 from the tobacco rod 60. Preferably,
is 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.
The cigarette 23 optionally includes at least one row of
perforations 12 adjacent the free end 15 of the cigarette 23. The
20 perforations can be formed as slits 17, which preferably extend
through the over wrap 71, the mat 66 and the inner wrap 84.
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
25 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.
Optional holes 16 provided in the mat 66 are covered by the
over wrap 71.
The perforations 12, 14 can be used to approximate
30 desired delivery levels for the cigarette 23, with the holes 16 being
used to adjust delivery with a lesser effect on the RTD
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
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mm so that the electrical smoking system 21 provides a smoker with a
familiar "mouth feel" during smoking.
The tobacco column 82 preferably comprises cut filler of a
typical blend of tobaccos, such as blends comprising bright, Burley,
s and Oriental tobaccos together with, optionally, reconstituted
tobaccos and other blend components, including traditional cigarette
flavors.
The free-flow filter 92 and the mouthpiece filter plug 94 are
preferably joined together as a combined plug with a plug wrap 101.
lo The plug wrap 101 is preferably a porous, low-weight plug wrap. The
combined plug is attached to the tobacco rod 60 by the tipping paper
64.
As described above, the electrically heated cigarette 23 can
comprise one or more sorbents that remove gas-phase constituents of
is 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
20 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.
In another preferred embodiment, the sorbent is one or more
suitable molecular sieve sorbent materials. Molecular sieve sorbents
25 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 WO-A-01/80973
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
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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
s having pores larger than one or more selected 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.
10 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(AinSi96-n03.92)-16H20, with n < 27, orthorhombic, Pnma], while zeolite
BETA is in the BEA structural classification family and represented by
the crystal chemical data [Na7(A17Si570128) 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.
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.
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.
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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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
s 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.
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 WO-A-+01/80973.
In a preferred embodiment, the fibers are shaped
ls 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.
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.
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.
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, 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
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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
s
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.
The fibrous sorbents preferably have a high loft with a suitable
packing density and fiber length such that parallel pathways are
io 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
is 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.
The amount of sorbent used in preferred embodiments of the
electrically heated cigarette 23 depends on the amount of selected
20 gas-phase constituents in the tobacco smoke and the amount of the
constituents that is desired to be removed from the tobacco smoke.
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,
25 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
30 flavoring is menthol and optionally at least one mint flavoring.
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
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the flavoring and provide for controlled release of the flavoring in
the cigarette during puff cycles.
The beads preferably comprise at least one encapsulating
material and at least one flavoring.
The encapsulating material
s
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
lo 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.
15 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
20 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
25 cigarette.
Consequently, the flavoring is preferably substantially
prevented from migrating in the cigarette, reacting with other
substances in the cigarette or with the environment, and deactivating
sorbent present in the cigarette.
The beads can have any desired shape, such as different regular
30 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
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can provide a more homogenous and controlled release of flavoring by
providing increased surface area of the beads.
The beads can be manufactured by any suitable process that
produces beads having the desired structure, composition, and size_
s 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 emulsiona
containing a binder, flavoring and optional additives to form beads,
which can be isolated and dried.
Processes for preparing beads
o containing an active ingredient, such as a flavor, are disclosed in
US-A-6 325 859
The electrically heated cigarette 23 preferably comprises ara
amount of the beads that provides a desired amount of the flavoring ira
.s 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.
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 temperature at which the flavoring is released from
25 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 03:
in the inner wrap 84 surrounding the tobacco plug 80.
30 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
35 temperature can be located at a first location in the cigarette that
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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
s 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.
In another preferred embodiment, the flavoring-release additive
includes a film. The film preferably encapsulates the flavoring and
o 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.
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 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.
Depending on the composition of the film, the minimum
temperature at which the film releases the flavoring can be
o 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
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the flavoring from being released until the film is heated to the
flavoring release temperature during smoking of the cigarette.
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.
The film can be manufactured by any suitable process that
produces a film having the desired structure, composition, and
o 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
L5 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
remove water and/or other solvents and form a solid film having
desired dimensions. Exemplary processes that can be used to prepare
n the films are described in US-A-3 006 347 and commonly-owned
US-A-4 715 390.
The electrically heated cigarette 23 preferably comprises an
amount of the film that releases a desired amount of the flavoring
n 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. Fos
example, if the film is applied to the mat, the weight of tobacco
n 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 plus
preferably is the weight basis for the amount of film applied in the
cigarette. Preferably, the weight of tobacco contained in the mat is
35 the weight basis for the amount of film applied to the mat, and the
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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.
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
lo 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.
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.
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
as
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,
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the inclusion complex comprises by weight up to about 20%, more
preferably from about 10% to about 15%, of the flavoring.
The host molecule of the inclusion complex is preferably a
cyclodextrin. Cyclodextrins are cyclic oligosaccharides including
s glucopyranose subunits, as described, for example, in US-A-3 426 011
and commonly-owned US-A-5 144 964, each of which is incorporated
herein by reference in its entirety. The inclusion complex is formed
when a flavoring material is mixed with a selected cyclodextrin in
solution.
The flavoring resides inside the cyclodextrin ring
lo structure.
The cyclodextrins and flavoring are typically co-
precipitated, filtered, and dried.
Alpha-cyclodextrin, beta-cyclodextrin and gamma-cyclodextrin
include six, seven and eight glucopyranose subunits, respectively. In
a preferred embodiment, the inclusion complex comprises beta-
15 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 torus
configuration including a hydrophobic cavity with a 7.5 A diameter and
hydrophillic upper and lower edges.
20 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
25 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.
The inclusion complex is preferably in powder form. The powder
preferably has maximum size of less than about 200 microns.
30
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
35 suitable process. The inclusion complex powder can alternatively be
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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
s 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
cigarette.
Exemplary processes that can be used to apply the
inclusion complex in the electrically heated cigarette are described
in commonly-owned US-A-5 144 964.
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
is 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.
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.
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,
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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 heated
cigarette that reach different temperatures during smoking in order to
S provide further controlled release of the flavoring during smoking.
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
io 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
is
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.
20
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.
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 slidingly receive the cigarette 23. A stop 183
located in the heater fixture 39 defines a terminal end of the
cigarette receiver 27 (FIG. 2).
Control circuitry 41 in the front housing portion 33
selectively establishes electrical communication between the power
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source 35a and one or more of the heating elements 37 during each puff
cycle.
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.
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
lo 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.
In a preferred embodiment, an indicator 51 is provided at a
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
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
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Cigarette detector 57 no longer detects the presence of a cigarette 23
and the indicator 51 is turned off.
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
lo each heating element 37 touches a fully inserted cigarette 23 is
referred to herein as the heater footprint or char zone 42.
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 the power source 35a through a connection 123
between the ring 110 and a pin 105.
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.
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The heater fixture 39 includes an air inlet port 1200 through
which air is drawn into the lighter. A pressure dr-op 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 prssure drop induced
s is selected such that it is within the range of pressure drop
detectable by the pressure sensor 45.
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
Lo smoking system 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
L5 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 alcmg 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
n lighter 25.
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
25 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.
The length of the void 91, tobacco paug 80, and the
N 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
35 response, to promote consistency in delivery.
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Electrically heated cigarettes according
to prf erred
embodiments can provide advantages.
By encapsulating one c>r more
added flavorings, especially volatile flavoring, the flavoring(s) can
be retained in the cigarette until it is smoked.
In additicxn, the
s flavoring is preferably temperature released in a controlled manner
during smoking, thereby providing the smoker with an exinanced
subjective characteristic of the cigarette. As the flavoring can be
retained in the flavoring-release additive until the cigarette is
smoked, deactivation of the sorbent in the cigarette is pre erably
o minimized. Consequently, the sorbent maintains its ability to remove
selected gas phase constituents from mainstream smoke.
Preferably, the sorbent comprises creped carbon paper adjacent
the mouthpiece plug.
In a preferred cigarette, a poly-prcogylene
sleeve is provided about the creped carbon paper which inhibits
s cigarette to cigarette migration of flavor volatiles and consequent
deactivation of the sorbent while the cigarettes are stored in a
cigarette pack. If the carbon paper is located in a cellulose acetate
tube, the activity level of the carbon could be degraded due to the
adsorption of triacitin by the carbon. The carbon paper is available
lo from Schweitzer-Mauduit, and filter plugs comprising the poly-
propylene sleeve and carbon paper are obtainable from Fiatrona.
Electrically heated cigarettes containing a sorbent comprising creped
carbon paper in a poly-propylene sleeve, located in a filter of the
cigarette, exhibit desirable RTD.
:5 FIGS. 7 and 8 show other preferred embodiments of an electrically
heated cigarette 23 including a filter 150. The filter 150 co-rt.-prises
a sorbent in the form of creped carbon paper and a poly-prfogylene
sleeve 154 surrounding the creped carbon paper.
In FIG. 7, El free-
flow filter 74 is in contact with (i.e., abut) a free-flow filter 92,
o which is in contact with (i.e., abut) the filter 150, which is in
contact with (i.e., abut) a mouthpiece filter plug 94. Alternatively,
in FIG. 8, the free-flow filter 74 is in contact with (i.e., E.but) a
solid segment 151, similar to the mouthpiece filter plug 94, which is
in contact with (i.e., abut) the filter 150, which is in contact with
(i.e., abut) the mouthpiece filter plug 94.
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In an embodiment, flavoring-release additive is located in the
tobacco mat, which surrounds the tobacco plug. The tobacco plug is
preferably free of flavoring-release additive, which allows cigarette
manufacture with the same blend of tobaccos in the tobacco plug for
5 either menthol or non-menthol cigarettes. Having the flavor in the
tobacco mat preferably provides a more efficient delivery of flavors
during smoking and a more immediate delivery of flavors during
initiation of a puff. As explained in commonly-owned US-A-5 692 525,
the length of the tobacco plug, void and heater-filler overlap can be
o adjusted to provide a desired taste, draw and delivery as well as
immediacy of response and/or consistency of delivery.
The encapsulation and placement of flavors within the matrix of
the tobacco mat also reduces the tendency of volatile flavors such as
menthol to migrate from the tobacco rod into the carbon bearing
5 portion of the filter. Accordingly, the activity level of the carbon
has enhanced shelf life and maintenance of its activity level.
Menthol flavoring is preferably provided in the form of a
temperature sensitive powder, such as a multi-stage dried (MSD)
powder.
By using additive materials in the form of temperature
:0 sensitive powders such as MSD powders, the additive materials can be
stored with reduced migration properties and can be controllably
released upon an application of a predetermined stimulus mechanism,
such as heat.
Thus, the additive materials in the temperature
sensitive powders such as MSD powder can have decreased levels of
15 evaporation and migration over time within the smoking article
because
of the properties rendered by the use of temperature sensitive powder.
Suitable menthol-containing powders can be obtained from Mane SA
located in Le Bar Sur Loup, France.
In a MSD process, additive materials are generally formed by
spray drying, fluid bed drying and/or belt drying in multiple steps to
form MSD powder.
In order to maintain the effectiveness of the
additive materials, the drying is completed at low temperature, where
the temperature is effective to dry but does not harm the additive
materials being dried.
For example, if the MSD powder contains a
flavorant, then drying temperatures used in making the MSD powder are
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below the flavorants' volatilization temperature.
For example, MSD
powder containing flavorants can be dried in multiple stages at
temperatures such as 20-50 C, 50-100 C, 100-150 C or 150-200 C.
Also, if spray drying is utilized, for example, the additive
s materials can be atomized from a liquid feed into a spray of droplets,
wherein the droplets can be placed in contact with a first temperature
drying air in a process chamber to remove moisture.
Next, the
droplets can be further dried in a second temperature drying air to
form dry temperature sensitive powder.
Preferably, the second
o temperature is cooler than the first temperature, but is still
sufficiently warm enough to provide effective drying properties. For
example, an additive material, such as menthol with a volatilization
temperature about 250 F, can be sprayed onto a substrate then passed
through a tunnel drier at 200 F to flash off a majority of the liquid,
s then can be air dried at room temperature to form a final temperature
sensitive powder.
As the powder is temperature sensitive, the powder contains and
reduces migration of the additive material until a temperature change
occurs, such as when heat is applied.
For example, a flavorant
so
additive material in a temperature sensitive powder in a cigarette can
be used for encapsulating and/or isolating the flavorant from other
parts of the cigarette, such as a sorbent, until a sufficient amount
of heat is applied to release the flavorant from the temperature
sensitive powder.
Consequently, the temperature sensitive powder can be used
effectively in smoking articles, which include sorbents, where the
additive materials would otherwise be sorbed by the sorbents. The use
of temperature sensitive powder allows additive materials to be
released upon smoking of a cigarette while not being released during
so storage, and also allows for the additive materials to modify smoke
properties from the cigarette.
Using additive materials, such as flavors, in temperature
sensitive powders, such as MSD powders, in a smoking article provides
advantages particularly for cigarettes containing sorbents. By using
ss the temperature sensitive powders, such as MSD powders, in cigarettes
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containing sorbents, sorption of the additive materials in the
temperature sensitive powders by the sorbents is substantially
prevented and controlled release of the additive materials is
provided.
For purposes of discussion the term "MSD powder" will be used to
describe the temperature sensitive powder even though any temperature
sensitive powder capable of controllably releasing additive materials
is contemplated herein. However, it is also noted that MSD powder is
a preferred temperature sensitive powder due to its manufacturing ease
o and consistency.
The term "temperature sensitive" is used herein to refer to a
temperature controlled response by a powder.
For example, as used
herein, a temperature sensitive powder containing additive materials
releases the additive materials when a predetermined amount of heat is
5 applied to release additive properties from the temperature sensitive
powder.
The terms "releasably disposed" or "controllably released" are
used herein to refer to the containment and controlled release of
additive materials properties from their MSD powder form. In the MSD
o powder form, the additive materials are sufficiently contained to
substantially avoid or minimize unwanted migration, such as, for
example, during storage of the smoking article with the MSD powder
therein. This term also includes, but is not limited to, the additive
materials in the MSD powder form being mobile enough to be
,5 controllably released when, for example, the MSD powder is subjected
to heat or combustion.
The MSD powder is a temperature sensitive powder, as mentioned
above, where the additive materials can emanate from the MSD powder
due to melting or other heat interactions with the powder.
The
o temperature sensitive characteristics of the additive materials and
the other constituents of the MSD powder allow for the additive
materials to be controllably released with heat.
For example, if
liquid menthol is incorporated into a MSD powder, where starch in
combination with a MSD process is used to form a MSD powder, the
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temperature at which the menthol liquefies is the critical temperature
for releasing (by melting) the menthol from the MSD powder.
The MSD powder is preferably incorporated into a tobacco mat to
provide encapsulated flavor that has reduced storage migration
properties with controlled release properties.
The MSD powder can include any material in addition to the
additive materials that will allow and potentially aid the controlled
release of the additive material or affect the properties of the
additive materials or the MDS powder upon application of heat or
lo burning.
For example, the MSD powder can include spray dryable
products, preferably food grade spray dryable products, such as
starch, sorbitol, maltodextrin or the like, which can provide
encapsulation of the additive materials, such as menthol, while not
significantly modifying desired characteristics, such as menthol
flavor, in the additive materials.
The MSD powder may be formed by any suitable MSD powder forming
technique, such as spray drying, fluid bed drying and/or belt drying,
where the drying is completed at temperatures below the melting or
volatilization levels of the additive materials and/or the MSD powder,
in order to produce additive materials in dried powder form. Should
too high a temperature be used, the additive material and/or the MSD
powder may melt or volatilize during processing and cause
agglomeration of the MSD powder or release of the additive materials
from the MSD powder form.
MSD powder with additive materials therein are formed by a multi-
stage drying process. In an exemplary multi-stage drying process, an
additive material is provided in liquid form, and then sprayed through
pressure nozzles or a rotary atomizer into heated air at a first
temperature to form droplets, where the heated air removes excess
liquid to form semi-dried droplets. Next, the semi-dried droplets are
fed into a secondary drying area, which is heated at a second
temperature different from the first temperature, where the secondary
drying area is used to remove excess liquid and dry the semi-dried
droplets into MSD powder.
In this way, liquid or viscous products,
such as liquid menthol (with emulsifiers and spray dryable products)
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can be converted into dried, heat sensitive powder, where improved
retention of the properties of the liquid products can be
accomplished.
A preferred method of making a MSD powder which provides an
encapsulated additive material includes liquefying an additive
material and mixing the liquefied additive material with an
emulsifier, such as modified food starch, to form an emulsion. The
additive material can be a liquid or viscous additive, such as liquid
menthol, or can be a solid additive, where the solid additive can be
lo liquefied through the use of solvent, heat, or other liquefying
methods.
The emulsion can then be mixed with a powder or other spray
dryable media, such as maltodextrin and/or sorbitol, where the powder
encapsulates the emulsion of additive and emulsifier.
Next, the
mixture of emulsion and powder can be sprayed and dried. Preferably,
the drying occurs in two stages. First, the sprayed mixture can be
sprayed through a heated air drier at a first temperature to remove a
majority of the liquid. Second, the sprayed mixture can be dried at a
second temperature for removing the remainder of the liquid from the
powder. Preferably, the first temperature is hotter than the second
temperature to reduce any damage that may be caused by prolonged
exposure to the higher temperature while allowing for efficient drying
of the final product. By using a plurality of temperature stages, the
additive material can be encapsulated and dried to a MSD powder, where
the additive material is releasably disposed in the MSD powder.
A tobacco mat is preferably formed by using a paper making-type
process to form a base web while concurrently or thereafter applying a
tobacco flavor material onto the base web. In the first portion of
this process, tobacco strip is washed with water and the solubles are
collected for use in a later coating step. The remaining (extracted)
tobacco fiber is used in the preparation of a slurry that will be used
in web/paper forming techniques to form the base web. To strengthen
the base web, carbon fibers may be added to the slurry by dispersing a
stock of carbon fibers in water and adding, for example, sodium
alginate, to promote dispersion. The carbon fiber dispersion is then
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added (optionally) to the tobacco-fiber slurry together with
(optionally) conventional flavors.
Any other hydrocolloid, may be
added in lieu of the sodium alginate as long as it preferably does not
interfere with the flavored tobacco response, is water soluble and has
5 a suitable molecular weight to impart strength to the tobacco mat.
The resultant mixture is then wet-laid onto a Fourdrinier wire of a
conventional paper-making machine or the like (such as a steel belt)
to form a base web. The solubles previously removed by washing the
tobacco strip are mixed with ground tobacco, and the mixture is coated
lo
onto one side of the base web, preferably with a standard reverse roll
coater located after a drum or Yankee dryer beyond the Fourdrinier
wire. The ratio of tobacco solubles to tobacco dust or particulates
in the added slurry is preferably set at a value between about 1:1 and
20:1, but preferably at or about 4 to 1. The added slurry may also be
15 cast or extruded onto the base web. Alternatively, the coating step
may be executed off-line separate from the production of the base web.
During or after the coating step, flavors that are conventional in the
cigarette industry are preferably added.
Pectin or other
hydrocolloids are added, preferably in a range of between 0.1 to 2.0%
20 by weight of the tobacco mat, to improve the coatability of the
slurry.
A preferred method of incorporating a flavoring-release additive
such as MSD powder into a tobacco mat is provided, where the tobacco
mat includes a flavoring-release additive such as MSD powder in a
25 layer on the tobacco mat for controlled release when a cigarette
incorporating the tobacco mat is smoked. A preferred method includes
forming a tobacco mat by forming a base web, then applying a slurry of
a flavoring-release additive such as MSD powder and a liquid,
preferably water, onto the base web, where the base web includes
30 ground tobacco.
The slurry can be spread across the tobacco mat.
Finally, the slurry can be dried through exposure to ambient air, or
can be dried by applying heat to the slurry, where the temperature of
the heat applied is effective to not melt or volatilize the additive
material in the flavoring-release additive.
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Preferably, the slurry of a flavoring-release additive such as
MSD powder and liquid is prepared just prior to application onto the
base web, so as to minimize the amount of time that the flavoring-
release additive is contained in the slurry, in order to avoid
volatilization of the additive material. More generically, the heat-
activated flavoring-release additive preferably has a low solubility
in water so as to be compatible with the process of tobacco mat-making
or the process of incorporating the flavoring-release additive in a
tobacco mat. The temperature of the slurry is preferably maintained
lo at a suitable temperature such as 80 to 100 F or about 90 F in order
to prevent crystallization of the additive material, such as menthol,
at lower temperatures and volatilization of the additive material at
higher temperatures.
Additionally, glycerine, pectin, and tobacco dust can also be
used in the wet slurry for structural and aesthetic purposes, where
the slurry can be spread with a doctor's knife (blade) to provide a
relatively uniform thickness for the tobacco mat.
A preferred method of making an encapsulating film on a tobacco
mat containing MSD powder is also provided, where the film allows
further reduction in migration of additive materials in the MSD powder
into a smoking article. By providing the film, the MSD powder can be
further isolated from other portions of a smoking article or other
smoking articles when packaged together thus reducing any interaction
between the additive material and the other portions of the smoking
article. The preferred method includes forming a tobacco mat, then
spraying a film onto the mat with a spray nozzle where the temperature
of the film in the spray nozzle is between 120 F and 160 F, more
preferably about 140 F, during spraying. Next, the film can be put in
a drier to expedite and complete drying, where the temperature in the
drier does not cause the film or the MSD powder to melt, burn or be
otherwise adversely affected.
A preferred embodiment of making a cigarette with MSD powder is
provided, where the MSD powder allows for controlled release of
additive materials to the cigarette when the cigarette is smoked. A
preferred method includes grinding tobacco and removing the tobacco
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liquid, also known as the concentrated extract liquor (CEL)
Next,
the remaining tobacco solids can be mixed with cellulose or the like
to form a base web.
Then, slurry including the MSD powder, CEL,
glycerine and/or pectin can be formed on the base web to form a MSD
powder layer on the base web.
Next, an optional layer of a tobacco dust can be applied and
spread across the base web on the slurry to provide further aesthetic
enhancements, such as additional tobacco flavoring, where the base web
and slurry can then be dried.
Finally, a film, preferably of
lo carrageenan or another relatively flavorless, heat responsive, food
grade film can be formed on the dried base web with the dried slurry
layer to seal the slurry constituents including the MSD powder, CEL,
glycerine and/or pectin under the film and thus prevent migration of
any portion of the base web or slurry including the MSD powder.
A preferred embodiment of making a tobacco mat including MSD
powder for a cigarette is provided, where the MSD powder allows flavor
components of tobacco smoke to be releasably disposed in the tobacco
mat.
A preferred method includes forming a tobacco mat with MSD
powder incorporated therein by mixing the MSD powder with tobacco,
then forming a tobacco mat from the mixture. Preferably, the tobacco
is ground or reconstituted tobacco such that the tobacco and the MSD
powder are miscible prior to forming the tobacco mat from the tobacco
and the MSD powder.
Preferably, the tobacco mat is formed such that the width of the
formed tobacco mat is greater than a width of the tobacco mat used in
a cigarette. For example, a tobacco mat can be formed about 12 to 18
inches wide.
Additionally, a film can optionally be sprayed onto the tobacco
mat using a spray nozzle, where the film is preferably heated to
liquefy the film material. For example, if carrageenan is used for
the film, the carrageenan can be heated to between about 120 F and
160 F, more preferably about 140 F to provide a desirable spraying
viscosity. Next, the film can be dried in ambient air, or a dryer or
a vacuum may be used to enhance the drying process.
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After the tobacco mat is formed (and the film formed if desired),
the tobacco mat can be slit or cut into sizes for use in a smoking
article. For example, if the tobacco mat is to be used in a standard
sized non-traditional cigarette, such as cigarettes Lased in
S electrically heated cigarette smoking systems, tobacco mat widths of
about 23.2 mm would be desired.
Another method of forming a film on a tobacco mat including MSD
powder for a cigarette is provided, where the drying process for the
film is part of a tobacco mat rolling process. A preferred method
o includes forming a first bobbin of tobacco mat including the MSD
powder prior to the forming of a film thereon. The tobacco mat from
the first bobbin can then be unwound from the first bobbin to a second
bobbin and wound onto the second bobbin for later incorporation in a
cigarette. Between the first and second bobbins as the tobacco mat
s travels from the first bobbin to the second bobbin, a film can be
applied to the tobacco mat. Preferably, the first bobbin is Located a
distance away from the second bobbin, where the distance allows for
the film to dry prior to being rolled into the second bobbin.
Preferably, the film is applied in several lines onto the tobacco
o mat, where surface tension spreads the film across the surface of the
tobacco mat.
Optionally, heat can be applied to the film and the
tobacco mat to dry the film while the tobacco mat is wound toward and
onto the second bobbin; however, preferably, the distance between the
first and second bobbins is a distance effective to allow drying of
s the film between the first and second bobbins without the use of added
heat. For
example, a distance effective to allow drying off a film
made of carrageenan on a tobacco mat about 16 inches wide, is about 33
feet between the first and second bobbin rolls.
Similarly, inclusion complexes comprising beta-cyclodextrin,
o e.g., for non-menthol cigarettes, are preferably incorporatzed into
tobacco mats, as disclosed above, to provide encapsulated flavor that
has reduced storage migration properties with controlled release
properties.
Thus, while the invention
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has been illustrated and described in accordance with various
preferred embodiments, it is recognized that variations and changes
may be made therein without departing from the invention as set forthi
in the claims.
