EP2858519B1

EP2858519B1 - Smoking article having high density tobacco

Info

Publication number: EP2858519B1
Application number: EP13737422.9A
Authority: EP
Inventors: Chrystele HOUPHOUET-BOIGNY; Poh Yoke TRITZ
Original assignee: Philip Morris Products SA
Current assignee: Philip Morris Products SA
Priority date: 2012-06-07
Filing date: 2013-06-04
Publication date: 2016-08-17
Anticipated expiration: 2033-06-04
Also published as: DK2858519T3; MX347010B; EP2858519A1; JP6270168B2; RU2625736C2; RS55150B1; LT2858519T; JP2015518730A; SI2858519T1; RU2014153521A; PL2858519T3; ES2598246T3; WO2013182995A1; HUE030474T2; PT2858519T; MX2014014971A

Description

This disclosure relates to smoking articles, such as cigarettes, having a tobacco substrate with a high density of tobacco relative to standard cigarettes.
Such cigarettes may have shorter tobacco rods relative to conventional cigarettes. However, cigarettes having shorter tobacco rods or shorter overall lengths may not be readily accepted by consumers. One way to maintain overall cigarette length of cigarettes having shortened tobacco rods is to lengthen the filter segment. However, lengthening the filter segment presents a number of practical challenges. For example, if the length of standard filter material is increased, the amount trapped by the filter may increase, resulting in less flavour delivery to a smoker. Further, the resistance to draw may be undesirably increased by increasing the length of the filter.
WO 03/039274 A1 discloses cigarette comprising a filter having a diameter about 5 to 10 mm and a length about 25 to 40 mm, cut tobaccos wrapped in a cigarette paper with a diameter about 5 to 10 mm and a length about 15 to 50 mm, wherein the tobacco has a density about 0.00005 gr/mm³ to 0.07 gr/mm³, preferably about 0. 0002 gr/mm³.
In this disclosure, cigarettes having a tobacco rod and a filter portion are described. The tobacco rod has tobacco at a density of greater than or equal to about 270 mg/cm³ and has a length that is less than or equal to 60% of the length of the cigarette. The filter portion has a length extending from a rod end adjacent the tobacco rod and a mouth end configured for insertion into a user's mouth. The filter portion includes a first filter plug in proximity to the rod end, a second filter plug in proximity to the mouth end, and one or more support elements disposed between the first and second filter plugs. The filter portion has one or more cavities between the first filter plug and the second filter plug that cumulatively occupy about 25% or more of the length of the filter portion. Preferably, the filter efficiency of the filter portion is less than or equal to about 40% efficiency.
While the cigarettes described in this disclosure have a high density tobacco rod of a shortened length relative to a conventional cigarette, they maintain attributes that may be desirable to consumers such as an overall cigarette length, filter firmness, and a resistance to draw similar to that of a conventional cigarette. Preferably, the overall smoking experience is similar to a conventional cigarette.
The filter portions of the cigarettes described herein are generally longer than those of conventional cigarettes and, as discussed above, have a first filter plug in proximity to the tobacco rod and a second filter plug in proximity to the mouth end of the cigarette. The filter portion has one or more central cavities between the first and second filter plugs that cumulatively occupy 25% or more of the length of the filter portion while maintaining an acceptable firmness. In embodiments, the cumulative length of the one or more central cavities occupies about 50% or more of the length of the filter portion, about 60% or more of the length of the filter portion, or about 70% or more of the length of the filter portion. In addition or alternatively, the one or more cavities cumulatively occupy about 85% or less of the length of the filter portion. In embodiments, the cavity or cavities may cumulatively have a length from about 20 mm to about 40 mm, for example about 30 mm. If the filter portion includes more than one cavity, such as two cavities, each cavity may have any suitable length to achieve a suitable cumulative length. For example, the length of each of cavities may independently be from about 10 mm to about 20 mm, such as about 15 mm.
A "cavity," as used herein, is a space defined by a portion of the filter that does not substantially contribute to the resistance to draw of the smoking article. Thus, some material may be present in the cavity or cavities, provided that the cavity or cavities do not affect, or do not substantially contribute to, the resistance to draw (for example, do not cumulatively account for more than about 10%, 5%, or 2% of total resistance to draw of the smoking article). In embodiments, the cavity or cavities are free or substantially free of any material.
The filter portion includes a plug wrap that circumscribes at least a portion of the filter portion. The plug wrap may be a stiff plug wrap having any suitable weight such as about 70 g/m² or greater or about 100 g/m² or greater. In addition, or in the alternative, the plug wrap may have a weight of less than 120 g/m². The plug wrap may also have a relatively high porosity, for example greater than about 1,000 Coresta units, or greater than about 5,000 Coresta units. In addition, or in the alternative, the plug wrap may have a porosity of less than about 10,000 Coresta units. The plug wrap may define the cavities and enhance firmness of the filter portion in the regions over cavities. Tipping paper or another suitable wrapper circumscribes the filter portion and may overlap the tobacco rod and attach the filter to the tobacco rod as is generally known in the art.
As described above, the filter portion further includes one or more support elements disposed between the first and second filter plugs. The one or more support elements provide structural support to the overlying plug wrap or tipping paper. The one or more support elements may be disposed at any location between the first and second filter plugs. If only one support element is employed, the support element is preferably disposed about equidistant between the first and second filter plugs for purposes of maximizing support over the distance between the filter plugs.
The filter portion may have any suitable firmness and preferably has a firmness similar to that of a filter in a conventional cigarette. The term "firmness" refers to resistance to compression. Firmness is typically determined by placing 15 cigarettes in three levels of six, five, and four in a holder having a fixed area trapezoidal shaped shoe. An opening at the top of the shoe has a width of slightly more than 28 mm, and a compression device has a compression plate that is 28 mm wide and 30 mm or more in length. The filled cigarette holder is placed under the compression device so that the compression plate overlaps the the filters of the cigarettes in the shoe from the mouth end of the cigarettes to a point that is 30 mm from the mouth end of the cigarettes. The cigarettes are initially compressed with a 100 g plate weight until they stabilize in place. Then, an additional weight of 1400 g is applied. At the end of 30 seconds, a compression value for all of the cigarettes together may be measured in millimeters, which is indicative of cigarette firmness.
The firmness measured for the filter portion of the cigarettes in this way is preferably less than about 6.0 mm, more preferably less than about 5.0 mm, most preferably less than about 4.0 mm. In addition, or in the alternative, the firmness of the filter portion of the cigarettes is greater than about 1.0 mm. In some embodiments, the firmness of the filter portion of the cigarettes is between about 1.0 mm and about 6.0 mm, preferabley between about 1.0 mm and about 5.0 mm, more preferably between about 1.0 mm and about 4.0 mm.
In embodiments, the support element is a third filter plug spaced between the first and second filter plug. Central cavities are formed between the first and third filter plugs and between the second and third filter plugs. The cumulative length of the central cavities may occupy about 25% or more of the length of the filter portion, such as about 50% or more of the length of the filter portion, about 60% or more of the length of the filter portion, or about 70% or more of the length of the filter portion. In addition, or in the alternative, the cumulative length of the central cavities may be about 85% or less of the length of the filter portion. In embodiments, the length of each of the cavities is independently from about 10 mm to about 20 mm, such as about 15 mm. The third filter plug provides support for the overlying filter portion components, such as plug wrap or tipping paper, to maintain desired firmness. The filter plugs may each independently be of any suitable length. In embodiments, the filter plugs are about 5 mm long or greater, such as about 6 mm long or greater. In embodiments, the filter plugs are less than about 15 mm long. In embodiments, the filter plugs are from about 5 mm long to about 10 mm long. Preferably, the filter plugs are about 8 mm long.
The filter plugs may be formed of any suitable material, such as standard cellulose acetate tow, paper or more generally cellulose sorbent material, other known polymeric fibers, or the like.
In embodiments, the support element is a flow restrictor disposed between the first and second filter plugs. The body of the flow restrictor defines one or more lumens, or restrictions, extending through the restrictor. The one or more lumens or restrictions have a total open area of sufficiently small size that the lumens or restrictions substantially contribute to the resistance to draw of the smoking article. For example, the cross-section area of the lumens or restrictions may cumulatively be less than about 20%, or less than about 10% of the cross section of the filter. In addition or alternatively, the cross-sectional area of the lumens or restrictions is cumulatively greater than about 0.05% of the cross-section of the filter.
Central cavities are formed between the first filter plug and the restriction of the flow restrictor and between the second filter plug and the restriction of the flow restrictor. The flow restrictor provides support for the overlying filter portion components, such as plug wrap or tipping paper, to maintain desired firmness. The restrictor element may be of any suitable length. In embodiments, the restrictor element spans the length between the first and second filter plugs, with a portion of the restrictor element forming the cavities. Preferably, the restrictor element has a length of about 5 mm or greater, such as about 6 mm or greater. In embodiments, the restrictor element has a length of about 40 mm or less. In embodiments the restrictor element has length of from about 5 mm to about 10, or about 8 mm. The length of the cavity between the first filter plug and the restriction of the restrictor element and the length of the cavity between the second filter plug and the restriction of the restrictor element may be the same or different and may be of any suitable length. In embodiments, the length of the cavity between the first filter plug and the restriction of the restrictor element and the length of the cavity between the second filter plug and the restriction of the restrictor element are independently from about 10 mm to about 20 mm, such as about 15 mm. The cumulative length of the cavities may occupy any suitable length of the filter portion, such as about 25% or more of the length of the filter portion, about 50% or more of the length of the filter portion, about 60% or more of the length of the filter portion, or about 70% or more of the length of the filter portion. In embodiments, the cumulative length of the cavities occupies about 85% or less of the length of the filter portion.
The restrictor element may be formed of any suitable material, such as a non-biodegradable polymer or a biodegradable polymer. The restrictor element may also be formed of dissolvable polymeric material. Examples of suitable materials for restrictor include polyethylene, polypropylene, polylactic acid, and the like. The restrictor may have any suitable number or lumens, provided that flow is restricted across the restrictor, which contributes substantially to the resistance to draw of the article or filter portion. In embodiments, the restrictor is a restrictor as described in EP 2,253 231 .
In embodiments, the support element is a tubular member disposed between the first and second filter plugs. The tube may span the length between the first and second filter plugs or may span only a portion of the length between the first and second filter plugs. The tube provides support for the overlying filter portion components, such as plug wrap or tipping paper, to maintain desired firmness. A central cavity may be formed within the tube and may extend to the first and second filter plugs, regardless of whether the tube spans the length between the first and second filter plugs or spans only a portion of the length between the first and second filter plugs. The length of the cavity or cavities occupies about 25% or more of the length of the filter portion, such as about 50% or more of the length of the filter portion, about 60% or more of the length of the filter portion, or about 70% or more of the length of the filter portion. In addition or alternatively, the length of the cavity occupies about 85% or less of the length of the filter portion. In embodiments, the length of the cavity is from about 20 mm to about 40 mm, such as about 30 mm.
The tubular member may be of any suitable length. Preferably, the tubular member has a length of about 5 mm or greater, such as about 6 mm or greater. In addition or alternatively, the tubular member may have a length of about 40 mm or less. In embodiments, the tubular member has a length of from about 5 mm to about 10 mm, or about 8 mm.
The tubular element may be formed of any suitable material, such as a non-biodegradable polymer or a biodegradable polymer. The tubular element may also be formed of dissolvable polymeric material. Examples of suitable materials for the tubular element include polyethylene, polypropylene, polylactic acid, or the like. The tubular element may have any suitable wall thickness, such as a thickness of greater than about 0.1 mm. In addition or alternatively, the tubular element may have a wall thickness of about 2 mm or less. In embodiments the wall thickness of the tubular element is from about 0.1 mm to about 0.8 mm. Preferably the wall thickness of the tubular element is about 0.3 mm.
In general, the cigarettes described herein have a tobacco rod and a filter portion adjacent the tobacco rod. In embodiments, the cigarettes may have an overall length that is similar to convention cigarettes. For example, the cigarettes may have a length from about 70 mm to about 130 mm, preferably from about 80 mm to about 130 mm, and more preferably from about 80 mm to about 120 mm.
The tobacco rod contains tobacco packed at a density of about 270 mg/cm³ or greater. In addition or alternatively, the tobacco rod contains tobacco at a density of about 600 mg/ cm³ or less. In embodiments, the tobacco is present in the rod at a density greater than about 290 mg/ cm³. Preferably, the tobacco is present in the rod at a density from about 270 mg/cm³ to about 400 mg/cm³, such as from about 290 mg/cm³ to about 380 mg/cm³, or from about 290 mg/cm³ to about 350 mg/cm³.
With such tobacco densities, it has been found that less tobacco may be employed than with standard cigarettes while providing the user with a smoking experience similar to that of conventional cigarettes. That is, even though the density of tobacco in the rod is higher than with conventional cigarettes (which typically have a tobacco density from about 180 mg/cm³ to about 250 mg/cm³), less tobacco may be employed while providing a similar puff count, a similar smoke particulate phase delivery, and the like. Accordingly, cigarettes with tobacco densities as described herein may result in lower overall manufacturing costs relative to conventional cigarettes. In some embodiments, to achieve use of less tobacco, the higher density rods are shorter than those of conventional cigarettes.
For example, in some embodiments, the length of the tobacco rod is about 50 mm or less, preferably about 45 mm or less. In embodiments, the length of the tobacco rod is about 20 mm or greater or about 25 mm or greater. In embodiments, the length of the tobacco rod is from about 20 to about 50 mm, or from about 25 mm to about 45 mm. Preferably, the length of the tobacco rod is about 35 mm.
In embodiments, the length of the tobacco rod is about 60% or less than the length of the cigarette, preferably 55% or less than the length of the cigarette, and more preferably 50% or less than the length of the cigarette. In addition, or in the alternative, the tobacco rod is about 25% or more of the length of the cigarette.
The length of the filter portion may be adjusted based on the length of the tobacco rod to achieve a desired overall length of the cigarette. In embodiments, the length of the filter portion is equal to or greater than about 40% of the length of the cigarette. Preferably the length of the filter portion is equal to or greater than about 45% of the length of the cigarette. More preferably, the length of the filter portion is equal to or greater than about 50% of the length of the cigarette. In addition, or in the alternative, the length of the filter portion is less than about 75% of the length of the cigarette. In embodiments, the length of the filter portion is about 30 mm or greater, such as about 40 mm or greater. In addition, or in the alternative, the length of the filter portion is less than about 70 mm. Preferably, the length of the filter portion is about 50 mm. A cigarette having a densely packed rod may produce any suitable number of puffs when measured by the standard ISO testing method, as defined in ISO 4387:2000. The puff count may vary due to the density of the tobacco in the rod. In embodiments, the puff count is from about 3 to about 8, such as from about 3 to about 7, and preferably about 4 to about 6.
In embodiments, the puff count of a cigarette having a high density tobacco rod as described in this disclosure produces a puff count lower than a conventional cigarette of a similar overall length. In some cases, this may be beneficial for consumers, for example when smoking time is limited. While the puff count may be lower than a similar length conventional cigarette, the overall amount of smoke particulate phase delivered to a smoker may be similar.
To achieve a desired amount of particulate phase delivery to a user, the filter portion may also be appropriately adjusted. For example, the overall filter efficiency may be adjusted. Filter efficiency refers to the percentage of particulate phase that is captured by the filter. That is, filter efficiency equals the weight of particulate phase captured by the filter divided by the weight of the mainstream particulate phase produced times 100%. Accordingly, a filter having a filter efficiency of about 50% captures about 50% of the mainstream particulate phase. Preferably, the cumulative efficiency of the filter portion is about 40% or less; more preferably about 35%; even more preferably about 30% or less. In this manner, a similar amount of particulate phase may be delivered to a user compared to a standard cigarette while using less tobacco.
The filter efficiency can be tested using the standard ISO smoking test method. The weight of all of the particulate phase is the weight of the particulate phase captured by the cigarette filters together with the weight of the particulate phase caught by the filter in the testing machine. The weight of the particulate phase captured by the cigarette filters can be determined by first cutting the cigarette rod off of a sampling of unsmoked cigarettes and measuring the weight of the filter. Another sampling of cigarettes is tested using the standard ISO smoking test method mentioned above, any remaining portion of the tobacco rod is removed, and the smoked filters are weighed. The difference between the weight of the smoked filters and the unsmoked filters is the weight of the particulate phase captured by the cigarette filters.
Cumulative efficiency of the filter may be adjusted in any suitable manner. For example, the overall length of filter plug material may be adjusted to alter the filter efficiency, with longer filter plugs having greater efficiency than shorter plugs when using the same material, manufacturing process, and density. By way of another example, the density of the filter material may be adjusted, with more dense filters having a greater efficiency than less dense filters when using the same materials. By way of further example, the material of the filter may be selected to achieve a desired filter efficiency, as different materials have different filtering efficiencies. Examples of filter materials that may be used include cellulose acetate tow, other cellulose sorbent material, other known polymeric fibers, or the like. In some embodiments, the rod end and mouth end filter segments described above are made of fibrous filtration material such as cellulose acetate. In embodiments, one or more filter segments, for example the rod end filter segment, include carbon or other sorbent material.
Cigarettes described in this disclosure may have any suitable resistance to draw (RTD). Preferably, the resistance to draw of the tobacco rod results in a RTD for the cigarette that is not appreciably different than standard cigarettes. The filter material, components and construction may also affect resistance to draw. Selection of filter material, components and construction may be determined by balancing the desired filter efficiency with the desired resistance to draw.
In embodiments, the cigarette has a resistance to draw of from about 70 mm of water gauge ("mm WG") and about 250 mm WG, preferably between about 80 mm WG and about 150 mm WG.
A cigarette described in this disclosure may include a ventilation zone. The ventilation zone has an increased porosity that allows a greater amount of airflow into the device along the ventilation zone as compared to areas adjacent to the ventilation zone. The ventilation zone, which is typically in the form of perforations in the wrapper, may be in an upstream cavity, a downstream cavity, or in a filter plug, or the like. In some embodiments, the ventilation zone is located on the upstream cavity or on the support element. Preferably, the ventilation zone provides between about 30% and about 90% dilution of the mainstream smoke, more preferably between about 50% and about 80% dilution of the mainstream smoke, wherein the "dilution" refers to the percentage by volume of air that is included in the smoke delivered to the consumer from the mouth end of the filter with the ventilation zone completely open. The level of ventilation or dilution achieved by the ventilation zone can be determined using ISO test method 9512:2002.
Referring now to FIGS. 1-8 , schematic drawings are depicted that illustrate various aspects of novel smoking articles. The drawings are not necessarily to scale and are presented for purposes of illustration and not limitation. The drawings depict various aspects described herein. However, it will be understood that other aspects not depicted in the drawings fall within the scope and spirit of this disclosure. Like numbers used in the figures refer to like components, steps and the like. However, it will be understood that the use of a number to refer to a component in a given figure is not intended to limit the component in another figure labelled with the same number. In addition, the use of different numbers to refer to components is not intended to indicate that the different numbered components cannot be the same or similar.

FIG. 1 is a schematic perspective view of a smoking article.
FIG. 2 is a schematic perspective view of an embodiment of a smoking article in which a portion of a wrapper is shown partially unfolded to reveal internal filter components.
FIG. 3 is a schematic longitudinal section of an embodiment of a smoking article shown in FIG. 2 .
FIG. 4 is a schematic longitudinal section of an alternative embodiment of a smoking article shown in FIG. 2 .
FIG. 5 is a schematic longitudinal section of another alternative embodiment of a smoking article shown in FIG. 2 .
FIG. 6 is a schematic perspective view of an embodiment of a smoking article in which a portion of a wrapper is shown partially unfolded to reveal internal filter components.
FIG. 7 is a schematic longitudinal section of an embodiment of a smoking article shown in FIG. 6 .
FIG. 8 is a schematic longitudinal section of an embodiment of a smoking article.

Referring now to FIG. 1 , a filtered cigarette 10 having a tobacco rod 12 and a filter portion 14 is shown. The tobacco rod 12 has tobacco packed at a density of about 270 mg/cm³ or greater, as discussed above, which is circumscribed by an outer wrapper.
The cigarette 10 has a length, L_C; the tobacco rod 12 has a length, L_R; and the filter portion 14 has a length, L_F. The length of the cigarette 10, Lc, and the length of the tobacco rod 12, L_R, may be as discussed above. For example, the length of the tobacco rod 12, L_R, may be about 60% or less than the length of the cigarette 10, L_C. The length, L_F, of the filter portion 14 may be adjusted based on the length, L_R, of the tobacco rod 12 to achieve a desired overall length, L_C, of the cigarette 10.
Referring now to FIG. 2 , the filter portion 14 includes a first filter plug 20 and a second filter plug 22. The first filter plug 20 is adjacent the tobacco rod 12. The second filter plug 22 is adjacent the mouth end of the cigarette 10. Preferably the second filter plug 22 is visible from, or extends to, the mouth end, as depicted, for purposes of providing an appearance approximating a conventional cigarette that has a filter at the mouth end. The length of the filter portion 14 (see, for example, L_F in FIG. 1 ) is defined as the length from the end of the first filter plug 20 that faces the tobacco rod 12 to the mouth end of the cigarette.
As shown in FIG. 2 , the filter portion 14 optionally includes a plug wrap 40 that circumscribes at least a portion of the filter portion 14. The plug wrap 40 may be a stiff plug wrap with any suitable weight, such as described above, and may enhance firmness of the filter portion 14 in the regions over cavities 60, 62. Tipping paper 50 or other suitable wrapper circumscribes the filter portion 14 and may overlap the tobacco rod 12 as is generally known in the art.
The filter portion 14 further comprises a support element 30 disposed between the first 20 and second 22 filter plugs. The support element 30 provides structural support to the overlying plug wrap 40 or tipping paper 50. The support element 30 may be disposed at any location between the first 20 and second 22 filter plugs. Preferably, the support element 30 is disposed about equidistant between the first 20 and second 22 filter plugs (that is, d₁ ≈ d₂) for purposes of maximizing support over the distance between the filter plugs. In embodiments, for example as described below and depicted in FIG. 6 , the support element 30 spans the distance between the first filter plug 20 and the second filter plug 22.
Regardless whether support element 30 spans the distance between the first 20 and second 22 filter plugs, the support element 30 contributes to the structural integrity of the filter portion 14. Other elements of the filter portion 14, such as the filter plugs 20, 22, plug wrap 40 and outer wrapper 50 also contribute to the structural support of the filter portion 14 and also contribute to the desired firmness of the filter portion 14.
The support structure in the embodiment depicted in FIG. 3 is a third filter plug 32, which is disposed between the first 20 and second 22 filter plugs, leaving cavity 60 between the second 22 and third 32 filter plugs and cavity 62 between the first 20 and third 32 filter plugs. In the embodiment depicted in FIG. 3 , the cumulative length (d₁ + d₂) and the individual lengths (d₁, d₂) of the cavities 60, 62 may be as described above.
Referring now to FIG. 4 , the filter portion 14 of the smoking article 10 includes a tubular element 34 as the support element. The body of the tubular element 34 defines a lumen extending through the element. The lumen has a diameter of sufficient size such that the tubular element 34 does not substantially contribute to resistance to draw as air flows freely through the lumen (as defined above). Accordingly, the cavity of the filter region 14 may be considered to include the region that includes the tubular element 34. That is, the length of the cavity may be considered to be d₃ as depicted in FIG. 4 , which may be as described above.
The tubular member 34 may be of any suitable length, and in embodiments may extend from the first 20 filter plug to the second 22 filter plug (see, for example, FIG. 7 below). In embodiments such as depicted in FIG. 4 , the length of the space between the first filter plug 20 and the tubular member 34 (d₂) and the length of the space between the second filter plug 22 and the tubular member 34 (d₁) may be the same or different and may be of any suitable length. Preferably, the tubular member 34 is spaced about equidistant between the first 20 and second 22 filter plugs.
Referring now to FIG. 5 , the filter portion 14 of the smoking article 10 includes a flow restrictor 36 as the support element. The body of the flow restrictor 36 defines a lumen or restriction extending through the restrictor. The lumen has a diameter of sufficiently small size that the restrictor 36 substantially contributes to resistance to draw of the smoking article 10, such as described above. The restrictor element 36 may include portions that do not substantially contribute to resistance to draw, such as depicted in and described below with regard to FIG. 8 .
Still referring to FIG. 5 , the restrictor element 36 is disposed between the first 20 and second 22 filter plugs, leaving a cavity 60 between the second filter plug 22 and the lumen or restriction of the restrictor 36 and a cavity 62 between the first filter plug 20 and the lumen or restriction of the restrictor 36.
The restrictor element 36 may be of any suitable length, such as described above. The length of the space between the first filter plug 20 and the lumens or restrictions of the restrictor 36 (d₂) and the length of the space between the second filter plug 22 and the lumens or restrictions of the restrictor 36 (d₁) may be the same or different and may be of any suitable length, such as described above. The cumulative length (d₁ + d₂) or individual lengths (d₁, d₂) of the cavities 60, 62 may be as described above.
In the embodiments depicted in FIGS. 2-5 , it may be desirable for at least a portion of the filter portion 14 to be circumscribed by a stiff plug wrap (see plug wrap 40 in FIG. 2 ) to provide additional support to, and add to the firmness of, the filter portion 14. By combining a stiff plug wrap with cavities 60, 62 that are free, or substantially free, of material under the stiff plug wrap, the filter portion 14 may have a firmness and general feel similar to a conventional cigarette.
Referring now to FIGS. 6-7 , a smoking article 10 includes a tobacco rod 12 having tobacco packed at a high density, such as described above, and a filter portion 14 adjacent the tobacco rod. The filter portion 14 includes a first filter plug 20 and a second filter plug 22, which may be as described above with regard to FIGS. 2-3 . A support element 30, in the form of a tubular element 34, is disposed between and abuts the first 20 and second 22 filter plugs. An optional stiff plug wrap 40 may circumscribe at least a portion of the filter portion 14. An outer wrapper 50, such as tipping paper, circumscribes at least a portion of the filter portion 14 and overlaps a portion of the tobacco rod 12. The tubular element 34 defines a lumen of sufficient size such that the tubular element 34 does not substantially inhibit flow and does not substantially contribute to resistance to draw (as discussed above). Because the tubular element 34 does not substantially contribute to resistance to draw, the cavity 64 of the filter portion is defined by the lumen of the tubular member 34 and has a length (d₃) defined by the length of the tubular member 34. The length (d₃) of the cavity 64 is preferably about 25% or more of the length of the filter portion 14.
The tubular element 34 may be a tubular element as described above with regard to FIG. 4 .
Referring now to FIG. 8 , a smoking article 10 that includes a high density tobacco rod 12 and a filter portion 14 is shown. The filter portion 14 includes a first filter plug 20 adjacent the tobacco rod 12 and a second filter plug 22 adjacent the mouth end. The filter plugs 20, 22 may be, for example, as described above with regard to FIGS. 2-3 .
A restrictor element 36 is disposed between the filter plugs 20, 22 and serves as a support element. The distance from the end of the restrictor 36 facing the first filter plug 20 to the first filter plug 20 is depicted as d₂. The distance from the end of the restrictor 36 facing the second filter plug 22 to the second filter plug 22 is depicted as d₁. The restrictor element 36 has flange portions extending from the outer edges to inner shoulders. These portions of the restrictor do not substantially interfere with gas flow and thus do not substantially affect resistance to draw (as discussed above). Between the shoulders, the restrictor 36 forms a lumen or restriction of sufficiently small dimension to restrict flow of gas across the restrictor and thus substantially contributes to resistance to draw. The distance from the lumen or restriction of the restrictor 36 facing the first filter plug 20 to the first filter plug 20 is depicted as d₄. The distance from the lumen or restriction of the restrictor 36 facing the second filter plug 22 to the second filter plug 22 is depicted as d₃.
Accordingly, the cumulative length of the cavity of the filter region may be considered the sum of d₃ and d₄.
The restrictor 36 may be a restrictor as described above with regard to, for example, FIG. 5 . The filter portion 14 and components thereof, are constructed taking into account the desired properties of the smoking article 10, such as firmness, feel, filter efficiency, resistance to draw, and the like.
All scientific and technical terms used herein have meanings commonly used in the art unless otherwise specified. The definitions provided herein are to facilitate understanding of certain terms used frequently herein.
As used in this specification and the appended claims, the singular forms "a", "an", and "the" encompass embodiments having plural referents, unless the content clearly dictates otherwise.
As used in this specification and the appended claims, the term "or" is generally employed in its sense including "and/or" unless the content clearly dictates otherwise.
As used herein, "have", "having", "include", "including", "comprise", "comprising" or the like are used in their open ended sense, and generally mean "including, but not limited to". It will be understood that "consisting essentially of", "consisting of", and the like are subsumed in "comprising," and the like.
Non-limiting examples are presented below of smoking articles illustrating some of the inventive aspects described herein.

Examples

Example 1. Support structure is filter plug

For purpose of illustration, reference to FIG. 3 is made, with reference numerals as they appear in FIG. 3 being shown in the following text in parentheses.
A cigarette (10) having an overall length of 84 mm and a diameter of 7.85 mm was constructed. The cigarette had a 30 mm long rod (12) into which 425 mg of tobacco was packed (approximate density of 293 mg per cubic centimeter). The filter (14) had a length of 54 mm and included three 8 mm long sections of standard cellulose acetate plugs (20, 22, 32).
The first plug (20) abutted the tobacco rod (12). The second plug (22) extends to the mouth end of the cigarette. The third plug (32) was placed equidistant between the first two plugs resulting in a 15 mm long (d₁) cavity (60) between the second plug (22) and the middle plug (32) and a 15 mm long (d₂) cavity (62) between the first plug (20) and the middle plug (32).
The filter portion (14) was circumscribed by a stiff plug wrap. Tipping paper, which circumscribed the stiff plug wrap and overlapped with the tobacco rod (12), was used to axially align and fix the filter portion (14) relative to the rod (12).
The resulting cigarette (10) was tested according to the ISO test method.

The following results were obtained:

Table 1: Results from first test article

	ISO Test Method	Results
Tar	ISO 4387:2000	4.2 mg
Nicotine	ISO 10315:2000	0.4 mg
Carbon monoxide	ISO 20774:2007	7.5 mg
Puff Count	ISO 4387:2000	4.78
Filter Ventilation	ISO 9512:2002	0%
Resistance to draw	ISO 6565:2011	203 mmWG

Example 2. Support structure is flow restrictor

For purpose of illustration, reference to FIG. 8 is made, with reference numerals as they appear in FIG. 8 being shown in the following text in parentheses.
A cigarette (10) having an overall length of 84 mm and a diameter of 7.85 mm was constructed. The cigarette had a 30 mm long rod (12) into which 425 mg of tobacco was packed (approximate density of 293 mg per cubic centimeter). The filter (14) had a length of 54 mm and included of two 8 mm long sections of standard cellulose acetate plugs (20, 22) and an 8 mm long flow restrictor element (36).
The first plug (20) abutted the tobacco rod (12). The second plug (22) abutted the mouth end. The flow restrictor element (36) was placed equidistant between the first two plugs resulting in a 15 mm long (d₁) cavity between the second plug (22) and the middle plug (32) and a 15 mm long (d₂) cavity between the first plug (20) and the middle plug (32).
The filter portion (14) was circumscribed by a stiff plug wrap. Tipping paper, which circumscribed the stiff plug wrap and overlapped with the tobacco rod (12), was used to axially align and fix the filter portion (14) relative to the rod (12).
The resulting cigarette (10) was tested according to ISO test methods

The following results were obtained:

Table 2: Results from second test article

	ISO Test Method	Results
Tar	ISO 4387:2000	1 mg
Nicotine	ISO 10315:2000	0.1 mg
Carbon monoxide	ISO 20774:2007	1.7 mg
Puff Count	ISO 4387:2000	5.5
Filter Ventilation	ISO 9512:2002	80%
Resistance to draw	ISO 6565:2011	111 mmWG

Example 3. Support structure is tubular member

For purpose of illustration, reference to FIG. 4 is made, with reference numerals as they appear in FIG. 4 being shown in the following text in parentheses.
A cigarette (10) having an overall length of 84 mm and a diameter of 7.85 mm was constructed. The cigarette had a 30 mm long rod (12) into which 425 mg of tobacco was packed (approximate density of 293 grams per cubic millimetres). The filter (14) had a length of 54 mm and included of two 8 mm long sections of standard cellulose acetate plugs (20, 22) and an 8 mm tubular element (34). The tubular element (34) was a hollow polypropylene tube.
The first plug (20) abutted the tobacco rod (12). The second plug (22) abutted the mouth end. The tubular element (36) was placed equidistant between the first two plugs resulting in a 15 mm long (d₁) cavity between the second plug (22) and the middle plug (32) and a 15 mm long (d₂) cavity between the first plug (20) and the middle plug (32).
The filter portion (14) was circumscribed by a stiff plug wrap. Tipping paper, which circumscribed the stiff plug wrap and overlapped with the tobacco rod (12), was used to axially align and fix the filter portion (14) relative to the rod (12).
The resulting cigarette (10) was tested according to ISO test methods.

The following results were obtained:

Table 3: Results from third test article

	ISO Test Method	Results
Tar	ISO 4387:2000	5.6 mg
Nicotine	ISO 10315:2000	0.57 mg
Carbon monoxide	ISO 20774:2007	7.4 mg
Puff Count	ISO 4387:2000	4.8
Filter Ventilation	ISO 9512:2002	0%
Resistance to draw	ISO 6565:2011	149 mmWG

Claims

A cigarette (10) having a length and comprising:
a tobacco rod (12) comprising tobacco of a density of greater than or equal to about 270 mg/cm³, wherein the tobacco rod has a length that is less than or equal to 60% of the length of the cigarette; and

a filter portion (14) having a length extending from a rod end adjacent the tobacco rod and a mouth end configured for insertion into a user's mouth,

wherein the filter portion comprises a first filter plug (20) in proximity to the rod end, a second filter plug (22) in proximity to the mouth end, and a support element (30) disposed between the first and second filter plugs, and

wherein the filter portion has one or more cavities (60, 62) between the first filter plug and the second filter plug that cumulatively occupy about 25% or more of the length of the filter portion.
A cigarette according to claim 1, wherein the filter efficiency of the filter portion is less than or equal to about 40% efficiency
A cigarette according to claim 1 or 2, wherein the tobacco rod comprises tobacco packed at a density of greater than or equal to about 290 mg/cm³.
A cigarette according to any one of claims 1-3, wherein the filter portion has a firmness of less than 6.0 mm.
A cigarette according to any of claims 1-4, wherein the support element comprises a filter plug (32).
A cigarette according to claim 5, wherein the support element consists of a filter plug.
A cigarette according to any of claims 1-4, wherein the support element comprises a restrictor (36).
A cigarette according to any of claims 1-4, wherein the support element comprises a hollow tube (34).
A cigarette according to any of claims 1-8, wherein the support element is biodegradable.
A cigarette according to any one of claims 1-9, wherein the tobacco rod has a length of less than or equal to about 50% of the length of the cigarette.
A cigarette according to any of claims 1-10, wherein the cumulative length of the one or more cavities of the filter portion is equal to or greater than about 50% of the length of the filter portion.
A cigarette according to any of claims 1-11, wherein the length of each of the first filter plug, the second filter plug and the support element is independently between about 5 mm and about 10 mm.
A cigarette according to any of claims 1-12, wherein the support element is disposed about equidistant between the first filter plug and the second filter plug.
A cigarette according to any of claims 1-13, wherein at least a portion of the filter portion comprises a stiff plug wrap (40) circumscribing at least a portion of the first and second filter plugs and the support element.
A cigarette according to claim 14, wherein the stiff plug wrap of the filter portion has a weight basis of equal to or greater than about 70 g/m².