US20070267033A1

Movatterモバイル変換

Info

Publication number: US20070267033A1
Application number: US11/702,617
Authority: US
Inventors: Munmaya Mishra; Susan Wrenn; Jay Fournier
Original assignee: Philip Morris USA Inc
Current assignee: Philip Morris USA Inc
Priority date: 2006-02-09
Filing date: 2007-02-06
Publication date: 2007-11-22
Also published as: US20170231266A1; JP2009525746A; EA200870241A1; US10537131B2; WO2007091181A3; US20150101624A1; US9668519B2; EP1986511A2; US11690395B2; US20200120971A1; KR20080092982A; ZA200806635B; MA30218B1; US20110079232A1; WO2007091181A2; US12279639B2; CA2641870A1; NO20083774L; AU2007213439A1; BRPI0707577A2

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 gamma cyclodextrin and at least one flavoring. Flavoring is released in a 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, powder and films.

Description

This application claims priority under 35 U.S.C. §119(e) to U.S. provisional Application No. 60/771,462, filed on Feb. 9, 2006, the entire content of which is incorporated herein by reference.

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.

An alternative to the more traditional cigarette is an 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-owned 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.

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.

Flavorings 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 cigarettes to remove gas-phase constituents from mainstream smoke. However, flavorings that have been incorporated in the cigarettes along with the activated carbon can be adsorbed by the activated carbon, which can clog pores of the activated carbon and consequently deactivate the activated carbon, thereby diminishing its ability to filter tobacco smoke.

For the foregoing reasons, flavorings that have been incorporated in cigarettes have not been totally satisfactorily delivered to the smoker. 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 can deactivate the sorbents and thereby reduce the sorbent's ability to remove gas phase constituents from tobacco smoke.

SUMMARY

In view of the above-described problems, a flavoring-release additive including gamma cyclodextrin and flavoring is provided. By providing flavoring within gamma cyclodextrin, the flavoring can be protected from loss during storage and distribution, and the flavoring can be released through thermal degradation upon heating of the gamma cyclodextrin.

In an exemplary embodiment, an electrically heated cigarette for an electrical smoking system, comprises at least one sorbent; and a flavoring-release additive comprising gamma cyclodextrin and at least one flavoring is provided.

In another exemplary embodiment, a method of making an electrically heated cigarette, comprising incorporating into an electrically heated cigarette (a) the at least one sorbent, and (b) the flavoring-release additive comprising gamma cyclodextrin and at least one flavoring is provided.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an exemplary 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 inFIG. 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 exemplary embodiment of an electrically heated cigarette for use in an electrical smoking system with the cigarette in a partially unassembled condition.

FIG. 4 illustrates an exemplary 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 inFIG. 4 with the cigarette withdrawn from the lighter.

FIG. 6 illustrates a heater fixture of the electrical smoking system.

FIG. 7,FIG. 8 andFIG. 9 illustrate exemplary flavoring release comparisons for different flavoring delivery encapsulants.

DETAILED DESCRIPTION

Gamma cyclodextrins, as used herein, are provided with flavoring to protect the flavoring from exposure to the atmosphere (e.g., ambient air, inside a package) and cigarette components (e.g., sorbents). The gamma cyclodextrin can reduce migration of flavoring in a cigarette prior to smoking. In addition, the flavoring can be thermally released from the gamma cyclodextrin flavoring-release additive in the cigarette in a controlled manner during smoking. Consequently, through inclusion of a flavoring guest molecule within a gamma cyclodextrin inclusion complex host molecule, the flavoring can be 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.

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, which are incorporated herein by reference in their entirety. Alpha-cyclodextrin, beta-cyclodextrin and gamma cyclodextrin include six, seven and eight glucopyranose subunits, respectively.

As discussed herein, a gamma cyclodextrin flavoring-release additive comprises a gamma cyclodextrin and at least one flavoring. The gamma cyclodextrin comprises a gamma cyclodextrin inclusion complex “host molecule,” and a flavoring “guest molecule.” In an exemplary embodiment, the flavoring is a lipophilic organic flavoring, which can be held within the inclusion hydrophobic cavity or hole in the gamma cyclodextrin formed by the eight glucopyranose subunits.

In commonly-owned U.S. Patent Publication No. 2004/0129280 to Woodson et al. (hereinafter “Woodson”) and commonly-owned U.S. Patent Publication No. 2005/0172976 to Newman et al. (hereinafter “Newman”), which are incorporated herein in their entireties for all purposes, Woodson and Newman disclose electrically heated cigarettes which can include beta cyclodextrin and flavoring. While the use of beta cyclodextrin can protect flavorings, such as menthol, the beta cyclodextrin only delivers low levels of the flavoring (i.e., 10% delivery compared to a control menthol cigarette).

Unexpectedly, however, gamma cyclodextrin can deliver disproportionately higher flavoring levels than beta cyclodextrin when flavoring is provided in equal amounts to equal amounts of gamma cyclodextrin and beta cyclodextrin. While not wishing to be bound by theory, it is believed that gamma cyclodextrin with its additional glucopyranose subunit creates a larger ring and therefore has a larger inclusion hydrophobic cavity or “hole” than an alpha or beta cyclodextrin. This larger hole, it is believed, allows gamma cyclodextrin to hold more flavoring within the ring (i.e., more of the flavoring is loaded into gamma cyclodextrin rings upon saturation, than is loaded into beta cyclodextrin rings upon saturation of the rings). Thus, it is believed that it is because of the additional glucopyronose subunit that gamma cyclodextrin can deliver higher levels of flavoring than the beta cyclodextrin. This is illustrated in the Example below.

In this Example, the effectiveness of gamma cyclodextrin in flavoring-release additives is compared to other flavoring-release additives. For comparison purposes, the flavoring used is menthol, wherein the menthol deliveries compared are menthol containing cigarettes, which include:

1) electrically heated cigarettes with gamma cyclodextrin with menthol flavoring from 20 wt. % to 33 wt. % (Samples (e), (f), (g) and (h) fromFIGS. 7 and 8);

2) electrically heated cigarettes with beta-cyclodextrin with 23 to 33 wt. % (Samples (c) and (d) fromFIGS. 7 and 8);

3) electrically heated cigarettes with menthol containing microcapsules (Sample (b) fromFIG. 7); and

4) control lit-end, or traditional menthol cigarettes (Sample (a) fromFIG. 7) (i.e., non-sorbent containing traditional cigarettes with menthol diffused into the cigarette).

The menthol containing cigarettes listed above, are compared below in Table 1.

It is noted that as used herein, the beta and gamma cyclodextrin materials can be commercially purchased, for example, from Cargill, Inc. of Cedar Rapids, Iowa, then combined with flavorant to form flavoring containing electrically heated cigarettes. Additionally, the microcapsules can be commercially purchased, for example, from V Mane Fils S A, Le Bar Sur Loup, France, and then inserted into a cavity of an electrically heated cigarette. Also, the control menthol traditional lit end cigarettes can be commercially purchased, for example, as MARLBORO Menthol Lights cigarettes from Philip Morris USA of Richmond, Va.

The beta and gamma cyclodextrin/menthol inclusion complexes can be formed according to the compositions listed in Table 1 by:

1) dissolving the cyclodextrin in water to form a cyclodextrin aqueous solution;

2) mixing menthol and ethanol to form a menthol mixture;

3) mixing the cyclodextrin aqueous solution with the menthol mixture to form a clear solution;

4) sonicating the clear solution for about 1 to about 15 minutes in order to precipitate cyclodextrin flavoring-release additives therefrom; and

5) spray drying the precipitated cyclodextrin flavoring-release additives at 200° C. or less under high vacuum to remove the water.

TABLE 1


Samples of Cyclodextrin (CD)/menthol inclusion complexes

	CD type(s)	Loading %	Inclusion Complex System

(c)	β-CD	20	40 g β-CD/12 g menthol/20 g
			ethanol/100 g water
(d)	β-CD	33	40 g β-CD/20 g menthol/20 g
			ethanol/100 g water
(e)	γ-CD	20	40 g γ-CD/10 g menthol/20 g
			ethanol/150 g water
(f)	γ-CD	23	40 g γ-CD/12 g menthol/20 g
			ethanol/150 g water
(g)	γ-CD	30	40 g γ-CD/17 g menthol/20 g
			ethanol/100 g water
(h)	γ-CD	33	80 g γ-CD/40 g menthol/40 g
			ethanol/200 g water

The loading % is based upon the amount of menthol included in the inclusion complex system. After loading the inclusion complex systems, the inclusion complexes can be incorporated into tobacco of electrically heated cigarettes, i.e., the mats of the electrically heated cigarettes. The delivery of menthol can then be calculated by the amount of menthol released from the inclusion complexes that is delivered, i.e., the amount released that is not adsorbed by sorbent downstream from the tobacco portion of the cigarette.

The four types of menthol containing cigarettes (including those from the above preparations) are compared inFIGS. 7-9. It is noted that the “menthol delivery” illustrated inFIGS. 7-9 is the delivery amount of menthol (downstream from any sorbents) by each of the menthol containing cigarette based upon a maximum or 100% menthol delivery defined as the amount of menthol that can be delivered to a smoker from the control traditional lit end menthol cigarette (sample (a) inFIG. 7). In other words, the % menthol delivery is the amount of menthol delivered by one of the four types of menthol containing cigarette (i.e., the electrically heated beta cyclodextrin-menthol cigarette, the electrically heated gamma cyclodextrin-menthol cigarette, the electrically heated microcapsule menthol cigarette or the control traditional lit end menthol cigarette) divided by the amount of menthol delivered by a control traditional lit end menthol cigarette.

In this example, 20% menthol delivery corresponds to a delivery of about 0.0125 mg of menthol per puff (with eight puffs per cigarette) or at least about 0.1 mg of menthol per cigarette (compared to about 0.5 mg of menthol per control traditional lit end menthol cigarette). However, it is noted that menthol amounts of at least 0.02 mg of menthol per puff or at least about 0.15 mg of menthol per cigarette (i.e., at least about 30% menthol delivery) can give a more desirable taste.

InFIGS. 7-9, as mentioned above, the “menthol delivery” or “% menthol delivery” is calculated based upon the amount of menthol per cigarette delivered (after any sorption by sorbents) to a smoker of each of the menthol containing cigarettes divided by the amount of menthol per cigarette delivered to a smoker from the control menthol traditional lit end cigarette to provide the % menthol delivery. In other words, 20% menthol delivery by an electrically heated gamma cyclodextrin-menthol cigarette can be delivered if the control menthol traditional lit end cigarette delivers 0.1 gram of menthol and the electrically heated gamma cyclodextrin-menthol cigarette delivers 0.02 grams.

Also, the amount of “menthol loading” or the “% menthol loading” is calculated based upon the total amount of additive when initially mixed. In other words, as shown in Table 1, sample (c), 20% menthol loading can be formed by loading 12 grams of menthol into 40 grams of beta cyclodextrin and 20 grams of ethanol (i.e., 12 g menthol/(40g β-CD+20 g ethanol)=20% menthol loading), wherein water can also be added in varying amount. It is noted that the % listed herein are each on a weight basis (and not an atomic basis). In other words, 20% menthol loading is intended to indicate 20% menthol loading by weight.

InFIG. 8, which is an enlarged view of samples (c)-(h), along withFIG. 9, which is a comparison of beta cyclodextrin and gamma cyclodextrin loading levels compared with delivery levels, the % menthol delivery of the beta cyclodextrin compared to the % menthol delivery of the gamma cyclodextrin is illustrated.

As shown inFIGS. 7-9, beta cyclodextrin provides low levels of menthol delivery even with higher loading levels as compared to any of the other samples. For example, the beta cyclodextrin samples with 20% menthol loading (sample (c) inFIGS. 7-9 and Table 1 with 40 grams beta cyclodextrin, 12 g menthol, 20 g ethanol and 100 g water) and 33% menthol loading (sample (d) inFIGS. 7-9 and Table 1) provide only about 7% menthol delivery and 11% menthol delivery, respectively. Additionally, as shown inFIGS. 7-9, gamma cyclodextrin with 20% menthol loading (sample (e) inFIG. 7 and Table 1) provided only about 15% menthol delivery.

Unexpectedly, however, as illustrated inFIGS. 7-9, menthol loading greater than 20% in gamma cyclodextrin delivers a disproportionate increase in % menthol delivery compared to the increase in % menthol loading. One would expect, based upon the change in % menthol delivery from the 20% menthol loaded beta cyclodextrin to the 30% menthol loaded beta cyclodextrin, that the % menthol delivery would increase approximately proportionally (seeFIG. 9 comparing the beta cyclodextrin at 20% menthol loading and 30% menthol loading).

For example, 20% menthol loading in a beta cyclodextrin provides only about 7% menthol delivery, and 33% menthol loading provides only about 11% menthol delivery. However, the change in % menthol delivery from the 20% menthol loaded gamma cyclodextrin to the 30% menthol loaded gamma cyclodextrin, showed a marked increase in % menthol delivery.

As shown inFIGS. 7 and 8 while a 20% menthol loading in gamma cyclodextrin leads to 15% menthol delivery, 23% menthol loading in gamma cyclodextrin (sample (f) inFIG. 7 and Table 1) leads to about 25% menthol delivery. Additionally, as illustrated inFIG. 9, again, 20% menthol loading in gamma cyclodextrin leads to 15% menthol delivery, however, 33% menthol loading in gamma cyclodextrin leads to about 37% menthol delivery.

Additionally, menthol loading over 20% in gamma cyclodextrin, unlike menthol loading in beta cyclodextrin or at 20%, can result in more than 15% or even 20% menthol delivery, as desired. As shown inFIGS. 7 and 8, 23% menthol loading in gamma cyclodextrin (sample (f) inFIG. 7 and Table 1) leads to about 25% menthol delivery. When compared to the 20% and 33% menthol loading in beta cyclodextrin, each of which results in 15% or less menthol delivery, the results of the % menthol delivery by the gamma cyclodextrin are unexpected.

Also, as shown inFIGS. 7 and 8, the increase in menthol delivery over 20% is disproportionate to the increase in % menthol loading. For example, as shown inFIGS. 7 and 8, by increasing the menthol loading by 3% to provide a 23% menthol loading ingamma cyclodextrin 10% more menthol can be delivered for gamma cyclodextrin. This is unexpected especially because such change is not noticed in the beta cyclodextrin. For example, 13% more menthol loading in beta cyclodextrin only provides a 4% increase in menthol delivery.

These unexpected results are further emphasized by the sample with 30% menthol loading into gamma cyclodextrin (sample (g) inFIG. 7 and Table 1), which results in about 34% menthol delivery. As shown by this sample, a 7% increase in menthol loading results in a 9% increase in menthol delivery. Similarly, as also shown inFIGS. 7-9, about 33% menthol loading (sample (h) inFIG. 7 and Table 1) results in about 37% menthol delivery.

As a result, by using gamma cyclodextrin with 23% or higher menthol loading, 25% or higher menthol delivery can be achieved. This is unexpected in view of the lower menthol delivery that can be achieved using the beta cyclodextrin and lower menthol loading levels. This is illustrated inFIG. 9, which compares equal loading levels of menthol in beta cyclodextrin and gamma cyclodextrin, wherein the gamma cyclodextrin has a much higher delivery for both 20% and 33% loading, but the 33% loading has a much larger difference between the beta cyclodextrin and the gamma cyclodextrin in % menthol delivery.

In exemplary embodiments, gamma cyclodextrin flavoring-release additives can be provided in smoking articles in forms including, but not limited to powders, films, solutions and/or suspensions. For example, gamma cyclodextrin flavoring-release additive can include powder or particles sized from 60 to 400 mesh. It is noted that the gamma cyclodextrin flavoring-release additive can be provided as a powder with a maximum particle size of less than about 200 microns, and more preferably less than about 1 micron and a minimum particle size of about 1 nm, preferably more than about 10 nm. Decreasing the size of the powder can provide a more homogenous and controlled release of flavoring by providing increased surface area of the powder.

As another example, the gamma cyclodextrin flavoring-release additive can be provided in a tobacco mat for an electrically heated cigarette. For example, a tobacco mat can be formed by mixing gamma cyclodextrin flavoring-release additive powder with tobacco dust in a slurry mixture to form a tobacco mat.

Alternatively, a gamma cyclodextrin flavoring-release additive film can be coated onto a tobacco mat for an electrically heated cigarette. For example, gamma cyclodextrin flavoring-release additive can be mixed with water and film forming agent, such as propylene glycol, then coated onto a tobacco mat. Exemplary processes that can be used to prepare the films are described in U.S. Pat. No. 3,006,347 and commonly-owned U.S. Pat. No. 4,715,390, each of which is incorporated herein by reference in their entirety.

The dimensions of a gamma cyclodextrin flavoring-release additive film are not limited. Preferably, the film has a thickness of up to about 150 microns or about 50 microns to about 150 microns, and more preferably up to about 75 microns. In another exemplary embodiment, a film of gamma cyclodextrin flavoring-release additive can be pre-formed, shredded and incorporated in the tobacco plug, and/or other selected locations that reach the flavoring release temperature. Exemplary processes that can be used to apply the gamma cyclodextrin flavoring-release additive in an electrically heated cigarette are also described in commonly-owned U.S. Pat. No. 5,144,964, which is incorporated herein by reference in its entirety.

The gamma cyclodextrin flavoring-release additive can also be used in a solution or a suspension. If the gamma cyclodextrin flavoring-release additive is provided in a solution or a suspension, the solution or suspension can be applied directly to one or more selected locations of one or more components of an electrically heated cigarette by any suitable process. For example, a solution of gamma cyclodextrin flavoring-release additive can be applied to a tobacco mat 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 an exemplary embodiment, gamma cyclodextrin flavoring-release additives can be disposed in at least one location in the electrically heated cigarette that reaches at least the minimum temperature at which the flavoring is released from the gamma cyclodextrin in the cigarette during smoking. For example, the gamma cyclodextrin flavoring-release additive can be disposed on an inner wrap, a tobacco mat, and/or an over wrap in the electrically heated cigarette. For example, the gamma cyclodextrin flavoring-release additive can be sprinkled on or adhered (with an adhesive) to the inner wrap, the tobacco mat and/or the over wrap.

Exemplary electricallyheated cigarettes23 include sufficient levels of flavoring and/or gamma cyclodextrin flavoring-release additive to provide a desired amount of the flavoring in the cigarettes. The cigarette can comprise, for example, from about 1 mg to about 30 mg of flavoring and/or about 1 mg to about 50 mg of gamma cyclodextrin flavoring-release additive.

The amount of gamma cyclodextrin flavoring-release additive in a cigarette can be based upon the weight of a cigarette or the weight of components in the cigarette. For example, an electrically heated cigarette can be, based on the total weight of tobacco in the tobacco mat and/or tobacco plug of the electrically heated cigarette, up to about 20%, and more preferably about 10% to about 15% gamma cyclodextrin flavoring-release additive. In other words, a cigarette containing 100 mg of tobacco preferably contains up to about 20 mg of gamma cyclodextrin flavoring-release additive.

Alternatively, the amount of gamma cyclodextrin flavoring-release additive in an exemplary embodiment, can include, based on the weight of the inner wrap, the tobacco mat and/or the over wrap, up to about 15%, and more preferably less than about 8%, of the gamma cyclodextrin flavoring-release additive. In other words, for a cigarette with a 10 mg tobacco mat, 1.5 mg of gamma cyclodextrin flavoring-release additive can be provided.

Gamma cyclodextrin flavoring-release additive can release flavoring at temperatures of at least about 200° C., such as about 200° C. to about 400° C. While not wishing to be bound by theory, it is believed that at temperatures of at least about 200° C., the ring of glucopyranose subunits of the gamma cyclodextrin opens and thus releases a flavoring guest molecule from the gamma cyclodextrin host molecule. It is also believed that at temperatures above about 400° C., the gamma cyclodextrin begins to decompose, thus causing flavoring release to be less uniform and less controlled.

In an exemplary embodiment, the gamma cyclodextrin flavoring-release additive is disposed in at least one location in the electrically heated cigarette that reaches at least the flavoring release temperature. For example, the gamma cyclodextrin flavoring-release additive can be disposed on an inner wrap, a tobacco mat and/or an outer wrap such that the gamma cyclodextrin flavoring-release additive can be heated by a heater element when the inner wrap, the tobacco mat and/or the outer wrap is heated.

The gamma cyclodextrin flavoring-release additive can further include an optional encapsulating material to provide additional barrier properties. The encapsulating material can include a binder, which can include, but is not limited to, one or more of carrageenan, gelatin, agar, gellan gum, gum arabic, guar gum, xanthum gum, and pectin. Other materials known in the art that can improve characteristics of an encapsulating material, e.g., film forming characteristics or additive stability, can optionally be added.

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, tobacco flavor, and combinations thereof. In an exemplary embodiment, the flavoring includes menthol or vanillin.

In exemplary embodiments, one or more sorbents capable of sorption or removal of selected gas-phase constituents from mainstream smoke are provided within a filter portion of an electrically heated cigarette. As used herein, the term “sorption” denotes 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 has 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 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 absorption of at least some portion of a component of mainstream tobacco smoke.

The term “mainstream smoke” includes a 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.

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 remove molecules of certain dimensions, while not removing other molecules with different dimensions (e.g., larger dimensions).

FIGS. 1 and 2 illustrate an exemplary embodiment of an electricallyheated cigarette23. The electricallyheated cigarette23 comprises atobacco rod60 and a filter tipping62 joined together by tippingpaper64. Thetobacco rod60 can include a tobacco web or amat66 folded into a tubular form about a free-flow filter74 at one end and atobacco plug80 at the other end.

An overwrap71 surrounds themat66 and is held together along a longitudinal seam. The overwrap71 retains themat66 in a wrapped condition about the free-flow filter74 andtobacco plug80.

Themat66 can comprise abase web68 and a layer oftobacco material70. Thetobacco material70 can be located along an inside surface or an 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. Thetobacco plug80 can comprise a relativelyshort tobacco column82 of cut filler tobacco, which is retained by a surroundinginner wrap84.

A void90 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 the free-flow filter74.

The tipping62 can comprise a free-flow filter92 located adjacent thetobacco rod60 and a mouthpiece filter plug94 at the distal end of the tipping62 from thetobacco rod60. The free-flow filter92 can be tubular and can transmit air with very low pressure drop. Themouthpiece filter plug94 closes off the free end of thetipping62.

Thecigarette23 optionally includes at least one row ofperforations12 adjacent thefree end15 of thecigarette23. The perforations can be formed asslits17, which can extend through the overwrap71, themat66 and theinner wrap84.

To further improve delivery, at least one additional row ofperforations14 comprisingslits17 can optionally be formed at a location along thetobacco plug80. The

perforations

12 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.

Optional holes

16 provided in themat66 are covered by the overwrap71. The

perforations

12,14 can be used to approximate desired delivery levels for thecigarette23, with theholes16 being used to adjust delivery with a lesser effect on the RTD.

Thecigarette23 can have 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.

Thetobacco column82 can comprise 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-flow filter92 and the mouthpiece filter plug94 can be joined together as a combined plug with aplug wrap101. Theplug wrap101 can be a porous, low-weight plug wrap. The combined plug is attached to thetobacco rod60 by the tippingpaper64.

As described above, the electricallyheated 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 an exemplary 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 exemplary embodiment, the sorbent is one or more suitable molecular sieve sorbent materials. Microporous, mesoporous, and/or macroporous molecular sieves may be used in the electricallyheated cigarette23, depending on the selected component(s) desired to be removed from mainstream tobacco smoke. Molecular sieve sorbents that may be used in the electricallyheated cigarette23 include, but are not limited to, one or more of the zeolites, mesoporous silicates, aluminophosphates, 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 an exemplary 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 electricallyheated 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 an exemplary embodiment, zeolite ZSM-5 and/or zeolite BETA is used. Zeolite ZSM-5 is in the MFI structural classification family and represented by the crystal chemical data [Na_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 EC allowing them to be incorporated in cigarette filters and/or the tobacco rod of the electricallyheated cigarette23.

In another exemplary embodiment, the sorbent incorporated in the electricallyheated cigarette23 has a composite composition. In such embodiment, the sorbent comprises, for example, activated carbon and one or more molecular sieve materials. For example, sorbent fibers can be impregnated with activated carbon and zeolite.

The sorbent can be incorporated in one or more locations of the electricallyheated 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 exemplary embodiment of an electricallyheated 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, thefibers152 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 an exemplary 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 exemplary 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.

Thefilters150 includingfibers152 can be formed, for example, by stretching a bundle of non-crimped sorbent fiber material, and can have a controlled total and per filament denier through using a pre-formed or in-situ formedsleeve 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.

Thefilter150 includingfibers152 can be incorporated in the electrically heated cigarette at one or more desired locations. Referring also toFIGS. 1 and 2, in an exemplary embodiment, thefilter150 can be substituted for the entire free-flow filter92. In another exemplary 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 can have 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 can 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 (i.e., not significantly affecting the total particulate matter (TPM) in the gas). By removing selected constituents, a significant reduction of the selected gas-phase constituents can be achieved. A sufficiently low packing density and a sufficiently short fiber length can be used to achieve such filtration performance.

The amount of sorbent used in exemplary embodiments of the electricallyheated 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.

FIGS. 4 and 5 illustrate an exemplary embodiment of an electrical smoking system in which exemplary embodiments of the electrically heated cigarette can be used. However, it should be understood that exemplary 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. Theelectrical 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 can be discarded after smoking.

Preferably, eachcigarette23 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 lighter25 includes ahousing31 having front and

rear housing portions

33 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 receive thecigarette23. Astop183 located in theheater fixture39 defines a terminal end of the cigarette receiver27 (FIG. 2).

Control circuitry41 in thefront housing portion33 selectively establishes electrical communication between thepower source35aand one or more of theheating elements37 during each puff cycle.

Therear housing portion35 of thehousing31 is constructed to be opened and closed to facilitate replacement of thepower source35a. It is noted that thefront housing portion33 can be removably attached to therear housing portion35 by mechanical engagement if desired.

Referring toFIG. 5, in an exemplary embodiment, the control circuitry41 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 can be located within thefront housing portion33 of the lighter25 and can communicate with a space inside theheater fixture39 via a port45aextending 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 an exemplary embodiment, anindicator51 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 can include a liquid crystal display. In an exemplary 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, thedetector57 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.

Theheater 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 an exemplary 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 orchar zone42.

As shown inFIG. 6, theheating elements37 can each include at least first and second serpentine,

elongate members

53aand53badjoined at atip54. The

heater portions

53a,53band54 form aheater blade120. Thetips54 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 a free end portion56aof one of theserpentine members53a, through at least a portion of thetip54 to the otherserpentine member53band itsend portion56b. It is noted that aconnection ring110 can be used to provide a common electrical connection to each of theend portions56b. In an exemplary embodiment, thering110 is connected to the positive terminal of thepower source35athrough aconnection123 between thering110 and apin105.

Theheating elements37 can be individually energized by thepower source35aunder the control of the control circuitry41 to heat thecigarette23 several times (i.e., eight times) at spaced locations about the periphery of thecigarette23. The heating renders puffs (i.e., 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.

Theheater 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 thetobacco plug80 and its relative position along thetobacco rod60 can be selected based on the construction and location of theheating elements37 of theelectrical smoking system21. When acigarette23 is properly positioned against a stop183 (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 the free end78 of thetobacco rod60 for everycigarette23 that is fully inserted into the lighter25.

The length of thetobacco plug80 of thecigarette23, the length of theheater footprint95, and the distance between theheater footprint95 and thestop183 can be 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 void91,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 exemplary 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 can be 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 minimized. Consequently, the sorbent maintains it ability to remove selected gas phase constituents from mainstream smoke.

The exemplary embodiments may be embodied in other specific forms without departing from the spirit of the invention. Thus, while the exemplary embodiments have been illustrated and described in accordance with various exemplary embodiments, it is recognized that variations and changes may be made therein without departing from the exemplary embodiments as set forth in the claims.