US20040129280A1 - Electrically heated cigarette including controlled-release flavoring - Google Patents

Abstract

Electrically heated cigarettes used in an electrical smoking system include a flavoring-release additive and sorbent effective to remove one or more gas-phase constituents of mainstream tobacco smoke. The flavoring-release additive includes at least one flavoring. The flavoring is released in the cigarette upon the flavoring-release additive reaching at least a minimum temperature during smoking. The flavoring-release additive can have various forms including, for example, beads, films and inclusion complexes. Electrical smoking systems including the electrically heated cigarettes, methods of making the cigarettes, and methods of smoking the cigarettes are also provided.

Description

RELATED APPLICATIONS
• This application claims priority under 35 U.S.C. §119 to U.S. Provisional Application No. 60/422,497 entitled ELECTRICALLY HEATED CIGARETTE INCLUDING CONTROLLED RELEASE FLAVORING and filed on Oct. 31, 2002, the entire content of which is hereby incorporated by reference.[0001]
BACKGROUND
• 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, each of which is hereby incorporated by reference in its entirety. 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 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. Pat. 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 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.[0007]
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 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. 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.[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.[0014]
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.[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:[0019]4 with the cigarette withdrawn from the lighter.
• FIG. 6 illustrates a heater fixture of the electrical smoking system.[0020]
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 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 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 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[0030]heated cigarette23. However, it should be understood that the electrically heated cigarette can have other configurations suitable for smoking in an electrically powered lighter. The electricallyheated cigarette23 comprises atobacco rod60 and a filter tipping62 joined together by tippingpaper64. Thetobacco rod60 preferably includes a tobacco web or “mat”66 folded into a tubular form about a free-flow filter74 at one end and atobacco plug80 at the other end.
• An over[0031]wrap71 surrounds the tobacco-containingmat66 and is held together along a longitudinal seam. The overwrap71 retains themat66 in a wrapped condition about the free-flow filter74 andtobacco plug80.
• The[0032]mat66 preferably comprises abase web68 and a layer oftobacco material70. Thetobacco material70 can be located along the inside surface or the outside surface of thebase web68. At the tipped end of thetobacco rod60, themat66 and the over wrap71 are wrapped about the free-flow filter plug74. Preferably, thetobacco plug80 comprises a relativelyshort tobacco column82 of cut filler tobacco, which is retained by a surroundinginner wrap84.
• A void[0033]90 is between the free-flow filter74 and thetobacco plug80. The void90 is an unfilled portion of thetobacco rod60 and is in fluid communication with the tipping62 through thefree flow filter74.
• The tipping[0034]62 preferably comprises a free-flow filter92 located adjacent thetobacco rod60 and a mouthpiece filter plug94 at the distal end of the tipping62 from thetobacco rod60. Preferably, the free-flow filter92 is tubular and transmits air with very low pressure drop. Themouthpiece filter plug94 closes off the free end of thetipping62.
• The[0035]cigarette23 optionally includes at least one row ofperforations12 adjacent thefree end15 of thecigarette23. The perforations can be formed asslits17, which preferably extend through the overwrap71, themat66 and theinner wrap84.
• To further improve delivery, at least one additional row of[0036]perforations14 comprisingslits17 can optionally be formed at a location along thetobacco plug80. Theperforations12 or14 may comprise a single row or a dual row ofslits17. The number and extent of theslits17 can be selected to control the resistance to draw (RTD) along the side walls of thecigarettes23 and the delivery.
• [0037]Optional holes16 provided in themat66 are covered by the overwrap71. Theperforations12,14 can be used to approximate desired delivery levels for thecigarette23, with theholes16 being used to adjust delivery with a lesser effect on the RTD.
• The[0038]cigarette23 preferably has a substantially constant diameter along its length. The diameter of thecigarette23, like more traditional cigarettes, is preferably between about 7.5 mm to 8.5 mm so that theelectrical smoking system21 provides a smoker with a familiar “mouth feel” during smoking.
• The[0039]tobacco column82 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.
• The free-[0040]flow filter92 and the mouthpiece filter plug94 are preferably joined together as a combined plug with aplug wrap101. Theplug wrap101 is preferably a porous, low-weight plug wrap. The combined plug is attached to thetobacco rod60 by the tippingpaper64.
• As described above, the electrically[0041]heated cigarette23 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.
• 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[0042]heated cigarette23 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, which is incorporated herein by reference in its entirety.
• 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 gas phase components of a gas that is desired to be filtered can be used in the electrically[0043]heated cigarette23, 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.
• 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 [Na[0044]_n(Al_nSi_96-nO₁₉₂)˜16H₂O, 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 electricallyheated cigarette23.
• In another preferred embodiment, the sorbent incorporated in the electrically[0045]heated cigarette23 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[0046]heated cigarette23, 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[0047]heated cigarette23. For example, the sorbent can placed in the passageway of the tubular free-flow filter74, in the free-flow filter92, and/or in thevoid space90. The sorbent can additionally or alternatively be incorporated in thetobacco plug80.
• FIG. 3 shows another preferred embodiment of an electrically[0048]heated cigarette23 including afilter150. Thefilter150 comprises a sorbent in the form of orientedfibers152 and asleeve154, 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.
• Alternatively, the[0049]fibers152 can comprise one or more sorbent materials, such as carbon, silica, zeolite and the like, impregnated in microcavity fibers, such as TRIAD™ 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.
• 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[0051]filters150 includingfibers152 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 formedsleeve154 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[0052]filter150 includingfibers152 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, thefilter150 can be substituted for the entire free-flow filter92. In another preferred embodiment, the free-flow filter150 can be substituted for a portion of the free-flow filter92. Thefilter150 can be in contact with (i.e., abut) the free-flow filter74, positioned between the free-flow filter74 and themouthpiece filter plug94, or in contact with (i.e., abut) themouthpiece filter plug94. Thefilter150 preferably has a diameter substantially equal to that of the outer diameter of the free-flow filter92 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 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[0054]heated cigarette23 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.
• As described above, the electrically[0055]heated cigarette23 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, ginger oil, and tobacco flavor. In a preferred embodiment, the 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 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 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, which is incorporated herein by reference in its entirety.[0060]
• The electrically[0061]heated cigarette23 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.
• In a preferred embodiment, the beads are disposed in at least one location in the electrically[0062]heated cigarette23 that reaches at least the minimum temperature at which the flavoring is released from the beads and into the cigarette during smoking. For example, the beads can be disposed in thetobacco rod60, in the void90 between thetobacco plug80 and the free-flow filter74, on one or more surfaces of the free-flow filter74, on or in themat66, and/or on or in theinner wrap84 surrounding thetobacco plug80.
• 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 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 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. Pat. Nos. 3,006,347 and commonly-owned 4,715,390, each of which is incorporated herein by reference in its entirety.[0068]
• The electrically[0069]heated cigarette23 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.
• In a preferred embodiment, the film is disposed in at least one location in the electrically[0070]heated cigarette23 that reaches at least the flavoring release temperature. For example, the film can be disposed on thetobacco plug80, on theinner wrap84 surrounding thetobacco plug80, on themat66, and/or on the over wrap71 surrounding the mat. When the film is disposed on theinner wrap84 and/or overwrap71, the weight of theinner wrap84 and/or overwrap71 is the weight basis for the amount of the film. In another preferred embodiment, the film can be preformed, shredded and incorporated in thetobacco plug80, 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.[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, 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 structure. The cyclodextrins and flavoring are typically co-precipitated, filtered, and dried.[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 torus configuration including a hydrophobic cavity with a 7.5 Å 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 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, which is incorporated herein by reference in its entirety.[0077]
• The electrically[0078]heated cigarette23 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.
• In a preferred embodiment, the inclusion complex is disposed in at least one location in the electrically[0079]heated cigarette23 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 theinner wrap84,mat66, and/or the overwrap71.
• 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 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[0081]electrical smoking system21 includes an electricallyheated cigarette23 and a reusable lighter25. Thecigarette23 is constructed to be inserted into and removed from acigarette receiver27, which is open at afront end portion29 of the lighter25. Once thecigarette23 is inserted, thesmoking system21 is used in a similar manner as a more traditional cigarette, but without lighting or smoldering of thecigarette23. Thecigarette23 is discarded after smoking.
• Preferably, each[0082]cigarette23 provides a total of at least eight puffs (puff cycles) per smoke. However, thecigarette23 can be constructed to provide a lesser or greater total number of available puffs.
• The lighter[0083]25 includes ahousing31 having front andrear housing portions33 and35, respectively. Apower source35a, such as one or more batteries, is located within therear housing portion35 and supplies energy to aheater fixture39. Theheater fixture39 includes a plurality of electrically resistive, heating elements37 (FIG. 6). Theheating elements37 are arranged within thefront housing portion33 to slidingly receive thecigarette23. A stop183 located in theheater fixture39 defines a terminal end of the cigarette receiver27 (FIG. 2).
• Control circuitry[0084]41 in thefront housing portion33 selectively establishes electrical communication between thepower source35aand one or more of theheating elements37 during each puff cycle.
• The[0085]rear housing portion35 of thehousing31 is constructed to be opened and closed to facilitate replacement of thepower source35a. Preferably, thefront housing portion33 is removably attached to therear housing portion35 by mechanical engagement.
• Referring to FIG. 5, in a preferred embodiment, the control circuitry[0086]41 is activated by a puff-actuatedsensor45, which is sensitive to either changes in pressure or changes in the rate of air flow that occur upon initiation of a draw on thecigarette23 by a smoker. The puff-actuatedsensor45 is preferably located within thefront housing portion33 of the lighter25 and communicates with a space inside theheater fixture39 via aport45aextending through aside wall portion182 of theheater fixture39. Once actuated by thesensor45, the control circuitry41 directs electric current to an appropriate one of theheating elements37.
• In a preferred embodiment, an[0087]indicator51 is provided at a location along the exterior of the lighter25 to visually indicate the number of puffs remaining in acigarette23, or other selected information. Theindicator51 preferably includes a liquid crystal display. In a preferred embodiment, theindicator51 displays a selected image when acigarette detector57 detects the presence of a cigarette in theheater fixture39. Thedetector57 can comprise any arrangement that senses the presence of an electrically heated cigarette. For example, the detector can comprise aninductive coil1102 adjacent thecigarette receiver27 of theheater fixture39 andelectric leads1104 that communicate thecoil1102 with an oscillator circuit within the control circuitry41. In such case, thecigarette23 can include a metallic element (not shown), which can affect inductance of the coil winding1102 such that whenever asuitable cigarette23 is inserted into thereceiver27, thedetector57 generates a signal to the circuitry41 indicating the cigarette is present. The control circuitry41 provides a signal to theindicator51. When thecigarette23 is removed from the lighter25, thecigarette detector57 no longer detects the presence of acigarette23 and theindicator51 is turned off.
• The[0088]heater fixture39 supports an insertedcigarette23 in a fixed relation to theheating elements37 such that theheating elements37 are positioned alongside thecigarette23 at approximately the same location for each newly insertedcigarette23. In a preferred embodiment, theheater fixture39 includes eight mutuallyparallel heater elements37, which are disposed concentrically about the axis of symmetry of thecigarette receiver27. The location where eachheating element37 touches a fully insertedcigarette23 is referred to herein as the heater footprint or char zone42.
• As shown in FIG. 6, the[0089]heating elements37 preferably each include at least first and second serpentine,elongate members53aand53badjoined at a tip54. Theheater portions53a,53band54 form aheater blade120. The tips54 are adjacent theopening55 of thecigarette receiver27. The opposite ends56aand56bof eachheating element37 are electrically connected to the opposite poles of thepower source35aas selectively established by the controller41. An electrical pathway through eachheating element37 is established, respectively, through aterminal pin104, aconnection121 between thepin104 and afree end portion56aof one of theserpentine members53a, through at least a portion of the tip54 to the otherserpentine member53band itsend portion56b. Preferably, aconnection ring110 provides a common electrical connection to each of theend portions56b. In a preferred embodiment, thering110 is connected to the positive terminal of thepower source35athrough aconnection123 between thering110 and apin105.
• Preferably, the[0090]heating elements37 are individually energized by thepower source35aunder the control of the control circuitry41 to heat thecigarette23 preferably eight times at spaced locations about the periphery of thecigarette23. The heating renders eight puffs from thecigarette23, 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.
• The[0091]heater fixture39 includes anair inlet port1200 through which air is drawn into the lighter. A pressure drop is induced upon the air entering the lighter such that thepuff sensor45 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 thepressure sensor45.
• The length of the[0092]tobacco plug80 and its relative position along thetobacco rod60 is preferably selected based on the construction and location of theheating elements37 of theelectrical smoking system21. When acigarette23 is properly positioned against a stop182 (FIG. 2) within the lighter of the electrical smoking system, a portion of each heating element contacts thetobacco rod60. This region of contact is referred to as aheater footprint95, which is that region of thetobacco rod60 where theheating element37 is expected to reach a temperature high enough to allow smoking of the cigarette without combustion of the cigarette paper, mat or tobacco. Theheater foot print95 can consistently locate along thetobacco rod60 at the samepredetermined distance96 from thefree end78 of thetobacco rod60 for everycigarette23 that is fully inserted into the lighter25.
• Preferably, the length of the[0093]tobacco plug80 of thecigarette23, the length of theheater footprint95, and the distance between theheater footprint95 and thestop182 are selected such that theheater footprint95 extends beyond thetobacco plug80 and superposes a portion of the void91 by adistance98. Thedistance98 is also referred to as the “heater-void overlap”98. The distance over which the remainder of theheater footprint95 superposes thetobacco plug80 is referred to as the “heater-filler overlap”99.
• The length of the void[0094]91,tobacco plug80, and the distribution of the perforation holes263 may be adjusted to adjust the smoking characteristics of thecigarette23, including adjustments in its taste, draw and delivery. The pattern ofholes263, the length of the void90 and the amount of heater-filler overlap99 (and heater-void overlap98) may also be manipulated to adjust the immediacy of response, to promote consistency in delivery.
• 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 flavoring is preferably temperature released in a controlled manner during smoking, thereby providing the smoker with an enhanced 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 preferably minimized. Consequently, the sorbent maintains it ability to remove selected gas phase constituents from mainstream smoke.[0095]
• The invention may be embodied in other specific forms without departing from the spirit of the invention. Thus, while the invention 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 forth in the claims.[0096]

Claims (37)

What is claimed is:

1. An electrically heated cigarette for an electrical smoking system, comprising:

at least one sorbent; and

a flavoring-release additive including at least one flavoring releasable in the electrically heated cigarette upon the flavoring-release additive being heated to at least a minimum temperature.

2. The electrically heated cigarette ofclaim 1, wherein the sorbent is activated carbon.

3. The electrically heated cigarette ofclaim 1, wherein the sorbent is zeolite.

4. The electrically heated cigarette ofclaim 1, wherein the flavoring is (i) menthol, or (ii) vanillin and gamma octalactone.

5. The electrically heated cigarette ofclaim 1, wherein the flavoring is at least one flavoring selected from the group consisting of menthol, mint, chocolate, licorice, fruit flavors, gamma octalactone, vanillin, ethyl vanillin, breath freshener flavors, spice flavors, methyl salicylate, linalool, bergamot oil, geranium oil, lemon oil, ginger oil, and tobacco flavor.

6. The electrically heated cigarette ofclaim 1, wherein the flavoring-release additive is in the form of beads.

7. The electrically heated cigarette ofclaim 6, wherein the beads comprise a binder selected from the group consisting of palm oil, konjac gum, hydroxypropylcellulose, xylitol, zein, sorbitol, maltitol, and hydroxypropylmethylcellulose.

8. The electrically heated cigarette ofclaim 6, wherein the beads have a maximum particle size of less than about 25 microns.

9. The electrically heated cigarette ofclaim 8, wherein the beads have a maximum particle size of less than about 1 micron.

10. The electrically heated cigarette ofclaim 6, which comprises, based on the total weight of tobacco in the electrically heated cigarette, up to about 20% by weight of the beads.

11. The electrically heated cigarette ofclaim 6, wherein the beads comprise by weight up to about 20% of the flavoring.

12. The electrically heated cigarette ofclaim 6, wherein the minimum temperature is about 40° C. and the beads are disposed in at least one location in the electrically heated cigarette that reaches at least about 40° C. during smoking of the cigarette.

13. The electrically heated cigarette ofclaim 6, wherein the beads are disposed in a tobacco rod, in a void between a tobacco plug and a free-flow filter, on a free-flow filter, on a tobacco-containing mat, and/or on an inner wrap surrounding the tobacco plug.

14. The electrically heated cigarette ofclaim 1, wherein the flavoring-release additive is a film.

15. The electrically heated cigarette ofclaim 14, wherein the film comprises a binder selected from the group consisting of carraghenan, gelatin, agar, gellan gum, gum arabic, guar gum, xanthum gum, and pectin.

16. The electrically heated cigarette ofclaim 14, wherein the film has a thickness of less than about 150 microns.

17. The electrically heated cigarette ofclaim 14, which comprises, based on the total weight of tobacco in the electrically heated cigarette, up to about 20% by weight of the film.

18. The electrically heated cigarette ofclaim 14, wherein the film comprises by weight up to about 20% of the flavoring.

19. The electrically heated cigarette ofclaim 14, wherein the film is in shredded form.

20. The electrically heated cigarette ofclaim 14, wherein the minimum temperature is about 50° C., and the film is disposed in at least one location in the electrically heated cigarette that reaches at least about 50° C. during smoking of the cigarette.

21. The electrically heated cigarette ofclaim 14, wherein the film is disposed in a tobacco plug, on an inner wrap surrounding the tobacco plug, on a tobacco-containing mat, and/or on an over wrap surrounding the mat.

22. The electrically heated cigarette ofclaim 1, wherein the flavoring-release additive is an inclusion complex which includes a host molecule and the flavoring is a guest molecule in the inclusion complex.

23. The electrically heated cigarette ofclaim 22, wherein the host molecule is beta-cyclodextrin.

24. The electrically heated cigarette ofclaim 22, which comprises, based on the weight of an over wrap and/or mat, less than about 15% by weight of the inclusion complex.

25. The electrically heated cigarette ofclaim 22, wherein the inclusion complex comprises up to about 20% of the flavoring.

26. The electrically heated cigarette ofclaim 22, wherein the minimum temperature is about 60° C., and the inclusion complex is disposed in at least one location in the electrically heated cigarette that reaches at least about 60° C. during smoking of the cigarette.

27. The electrically heated cigarette ofclaim 22, wherein the flavoring-release additive is disposed on an inner wrap surrounding a tobacco plug, on a tobacco-containing mat, and/or on an over wrap surrounding the mat.

28. The electrically heated cigarette ofclaim 1, wherein the sorbent is fibers.

29. The electrically heated cigarette ofclaim 28, wherein the fibers are continuous or non-continuous fibers.

30. The electrically heated cigarette ofclaim 28, wherein the fibers are impregnated with at least one sorbent.

31. A method of making an electrically heated cigarette according toclaim 1, comprising incorporating into an electrically heated cigarette (a) the at least one sorbent, and (b) the flavoring-release additive including at least one flavoring releasable in the electrically heated cigarette upon the flavoring-release additive being heated to at least the minimum temperature.

32. A method of smoking the electrically heated cigarette ofclaim 1, comprising heating a portion of the electrically heated cigarette to form smoke and drawing the smoke through the electrically heated cigarette, the sorbent removing at least one selected gas-phase constituent from mainstream smoke.

33. An electrical smoking system, comprising:

a lighter; and

at least one electrically heated cigarette including:

at least one sorbent; and

a flavoring-release additive including at least one flavoring which is releasable in the electrically heated cigarette upon the flavoring-release additive being heated to at least a minimum temperature.

34. An electrically heated cigarette, comprising:

at least one sorbent; and

at least one flavoring-release additive in a form selected from the group consisting of beads, film, and an inclusion complex, each flavoring-release additive including at least one flavoring releasable in the electrically heated cigarette upon the flavoring-release additive being heated to at least a minimum temperature.

35. The electrically heated cigarette ofclaim 34, wherein the flavoring-release additive comprises at least two flavoring-release additives in the form of beads, film, and/or an inclusion complex, each flavoring-release additive having a different minimum temperature at which the flavoring is released during smoking of the electrically heated cigarette.

36. A method of making an electrically heated cigarette according toclaim 34, comprising incorporating into an electrically heated cigarette (a) the at least one sorbent, and (b) the at least one flavoring-release additive in the form of beads, film, and/or an inclusion complex, the flavoring-release additive including at least one flavoring releasable in the electrically heated cigarette upon the flavoring-release additive being heated to at least the minimum temperature.

37. A method of smoking the electrically heated cigarette ofclaim 34, comprising heating a portion of the electrically heated cigarette to form smoke and drawing the smoke through the electrically heated cigarette, the sorbent removing at least one selected gas-phase constituent from mainstream smoke.

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