Aerosol-generating article with non-circular perforations in ventilation zone

Abstract

To provide a new and improved aerosol-generating article.SOLUTION: The invention relates to an aerosol-generating article (10) comprising a rod (12) of aerosol-generating substrate. The aerosol-generating article further comprises a ventilation zone (60) arranged downstream the rod of aerosol-generating substrate. The ventilation zone comprises perforations. One or more of the perforations have a non-circular cross-section having an ovality, the ovality being the ratio of a large diameter of a perforation divided by a small diameter of the perforation, of at least 1.5. A thickness of the peripheral wall of the ventilation zone is between 0.1 millimeter and 2.5 millimeter. One or more perforations have a width of between 0.05 millimeter and 0.2 millimeter and a length of between 0.25 millimeter and 1.0 millimeter. The invention further relates to an aerosol-generating system comprising an aerosol-generating device having a cavity for receiving an aerosol-generating article. The invention further relates to a method for manufacturing an aerosol-generating article.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an aerosol-generating article. The aerosol-generating article may include an aerosol-generating substrate and may be adapted to generate an inhalable aerosol upon heating. The present invention further relates to an aerosol-generating system comprising an aerosol-generating device having a cavity for receiving the aerosol-generating article. The present invention further relates to a method for manufacturing the aerosol-generating article. [Background technology]

[0002] Aerosol-generating articles in which an aerosol-generating substrate, such as a tobacco-containing substrate, is heated rather than combusted are known in the art. Typically, in such heated smoking articles, an aerosol is generated by transferring heat from a heat source to a physically separated aerosol-generating substrate or material, which may be located in contact with, within, around, or downstream of the heat source. During use of the aerosol-generating article, volatile compounds are released from the aerosol-generating substrate by heat transfer from the heat source and are entrained in the air drawn through the aerosol-generating article. As the released compounds cool, they condense to form an aerosol.

[0003] Numerous prior art documents disclose aerosol generating devices for consuming aerosol-generating articles. Such devices include, for example, electrically heated aerosol generating devices in which an aerosol is generated by heat transfer from one or more electric heater elements of the aerosol generating device to an aerosol-generating substrate of the heated aerosol-generating article. For example, an electrically heated aerosol generating device has been proposed that includes an internal heater blade adapted to be inserted into the aerosol-generating substrate. Alternatively, an inductively heatable aerosol-generating article has been proposed that includes an aerosol-generating substrate and a susceptor disposed within the aerosol-generating substrate. Alternatively, a susceptor arrangement may be disposed within the aerosol generating device so as to at least partially surround a cavity for receiving the aerosol-generating article. Summary of the Invention [Problem to be solved by the invention]

[0004] Aerosol-generating articles in which a tobacco-containing substrate is heated rather than combusted present several challenges not faced by conventional smoking articles. First, the tobacco-containing substrate is typically heated to a significantly lower temperature compared to the temperature reached by the combustion front of a conventional cigarette. This can affect nicotine release from the tobacco-containing substrate and nicotine delivery to the consumer. At the same time, if the heating temperature is increased in an attempt to enhance nicotine delivery, the aerosol generated typically needs to be cooled more extensively and more quickly before reaching the consumer. However, technical solutions commonly used to cool mainstream smoke in conventional smoking articles, such as providing a high-filtration efficiency segment at the mouth end of the cigarette, can have undesirable effects in aerosol-generating articles in which the tobacco-containing substrate is heated rather than combusted, as this can reduce nicotine delivery. Second, there is a general need for aerosol-generating articles that are easier to use and have improved practicality in general.

[0005] It is desirable to provide an aerosol-generating article that can be produced efficiently and rapidly, and that preferably has a satisfactory RTD and low RTD variation between articles. It is desirable to provide an aerosol-generating article that provides efficient cooling. It is desirable to provide an aerosol-generating article that efficiently cools the aerosol. It is desirable to provide an aerosol-generating article that efficiently cools the vaporized aerosol-forming substrate. It is desirable to provide an aerosol-generating article that provides efficient mixing of ambient air with the vaporized aerosol-forming substrate.

[0006] It would be desirable to provide new and improved aerosol-generating articles adapted to achieve at least one of the above desired results. [Brief explanation of the drawings]

[0007] [Figure 1] 1 shows a schematic cross-sectional side view of an aerosol-generating article according to the present invention. [Figure 2] 1 shows a cross-sectional view of an aerosol-generating article at the location of a ventilation zone. [Figure 3] 1 shows non-circular perforations in the ventilation zone. DETAILED DESCRIPTION OF THE INVENTION

[0008] According to an embodiment of the present invention, there is provided an aerosol-generating article that may comprise a rod of aerosol-generating substrate. The aerosol-generating article may further comprise a ventilation zone disposed downstream of the rod of aerosol-generating substrate. The ventilation zone may comprise perforations. One or more of the perforations may have a non-circular cross-section having an ellipticity, the ellipticity being the ratio of the major diameter of the perforation divided by the minor diameter of the perforation, of at least 1.5. The thickness of the peripheral wall of the ventilation zone may be between 0.1 millimeters and 2.5 millimeters.

[0009] According to an embodiment of the present invention, there is provided an aerosol-generating article comprising a rod of aerosol-generating substrate. The aerosol-generating article further comprises a ventilation zone disposed downstream of the rod of aerosol-generating substrate. The ventilation zone comprises perforations. One or more of the perforations have a non-circular cross-section having an ellipticity, the ellipticity being the ratio of the major diameter of the perforation divided by the minor diameter of the perforation, of at least 1.5. The thickness of the peripheral wall of the ventilation zone is between 0.1 millimeters and 2.5 millimeters.

[0010] Having a non-circular cross-section can improve mixing between the ambient air drawn into the ventilation zone through the perforations and the air drawn into the ventilation zone through the rod of the aerosol-forming substrate. The flow of ambient air drawn into the ventilation zone can be influenced by the shape of the perforations. Non-circular perforations can create a more turbulent airflow, which can result in improved mixing between the ambient air and the air drawn through the rod or the aerosol-forming substrate.

[0011] The cross-sectional shape of the perforations can be seen in a plane parallel to the central axis of the ventilation zone, which is preferably the same as the central axis of the entire aerosol-generating article. The cross-sectional shape of the perforations can be seen at the outermost or peripheral open area of ​​the perforations.

[0012] One or more of the perforations may have an elliptical cross-section.

[0013] One or more of the perforations may be slit-shaped.

[0014] For one or more of the perforations, the length of the perforation may be greater than the width of the perforation, preferably the length is 1.5 times greater than the width, more preferably 2.5 times greater than the width, more preferably 4 times greater than the width, and most preferably 5 times greater than the width, for one or more of the perforations.

[0015] For one or more of the perforations, the longitudinal axis of the perforation may be parallel to the longitudinal axis of the aerosol-generating article.

[0016] The one or more perforations may have a width of 0.05 mm to 0.2 mm, preferably 0.1 mm to 0.15 mm, and most preferably 0.11 mm to 0.13 mm.

[0017] The one or more perforations may have a length of 0.25 mm to 1.0 mm, preferably 0.4 mm to 0.8 mm, and most preferably 0.5 mm to 0.6 mm.

[0018] The ovality of the perforations may be at least 2, preferably at least 3, more preferably at least 4, and most preferably at least 5.

[0019] Between 5 and 15 perforations may be provided within the ventilation zone. Preferably, between 7 and 14 perforations may be provided within the ventilation zone. Preferably, between 9 and 13 perforations may be provided within the ventilation zone. Preferably, between 10 and 12 perforations may be provided within the ventilation zone. Preferably, the number of perforations is 11.

[0020] Having a ventilation zone with perforations can allow ambient air to be drawn into the ventilation zone. This ambient air may mix with the air drawn through the rod of the aerosol-forming substrate. The rod of the aerosol-forming substrate may be heated by the aerosol generating device to volatilize the aerosol-forming substrate. The volatilized aerosol-forming substrate may be entrained in the air flowing through the rod of the aerosol-forming substrate. This airflow mixes with the ambient air downstream of the rod of the aerosol-forming substrate in the ventilation zone. The mixture of ambient air and air drawn through the rod of the aerosol-forming substrate cools to form an aerosol. Having 10 to 12 perforations improves mixing between the ambient air drawn into the ventilation zone through the perforations and the air drawn through the rod of the aerosol-forming substrate. This improved mixing may result in improved aerosol generation. Without being bound by any theory, it has been found that 10 to 12 perforations leads to the best mixture of ambient air and air carrying volatilized aerosol-forming substrate. The reason may be that this relatively small number of perforations requires relatively large perforations to allow a sufficient amount of ambient air to be drawn into the ventilation zone, which may lead to relatively strong turbulence between the two airflows and therefore improved mixing of the two airflows.

[0021] Each perforation may have a central axis. The aerosol-generating article may have a central axis. The minimum distance between the central axis of each perforation and the central axis of the aerosol-generating article may be 3% to 15% of the outer diameter of the aerosol-generating article, preferably 4% to 13% of the outer diameter of the aerosol-generating article, more preferably 5% to 10% of the outer diameter of the aerosol-generating article, and most preferably 6% of the outer diameter of the aerosol-generating article.

[0022] The central axis of each perforation may be angled at an angle of 3 to 20 degrees, preferably 4 to 15 degrees, more preferably 5 to 10 degrees, and most preferably 7 degrees relative to the radial direction of the aerosol-generating article.

[0023] This inclination of the perforations can lead to a turbulent flow of ambient air being drawn through the perforations into the ventilation zone, which may improve mixing of the ambient air with the air drawn through the rod of the aerosol-forming substrate.

[0024] The inner diameter of the hollow tubular ventilation zone may be between 2.5 mm and 7.5 mm, preferably between 3.5 mm and 6.5 mm, more preferably between 4.0 mm and 6.0 mm, more preferably between 4.5 mm and 5.5 mm, and most preferably 5.0 mm.

[0025] The ventilation zone may be disposed within a second hollow tubular segment of the aerosol cooling element. The second hollow tubular segment may be 130 mm 3 ~200mm 3 , preferably 155mm 3 ~185mm 3 , more preferably 170 mm 3 may have an internal volume of

[0026] The perforations may be arranged in the peripheral wall of the ventilation zone. The perforations may be arranged asymmetrically within the peripheral wall. The arrangement may be asymmetric in that it may not be point symmetric with respect to any point on the central longitudinal axis of the aerosol-generating article. Additionally or alternatively, the arrangement may be asymmetric in that it does not further have line symmetry.

[0027] The perforations may be arranged in the peripheral wall of the ventilation zone with a non-constant pitch. The pitch of the perforations is the distance between the perforations. The non-constant pitch arrangement of the perforations may be an arrangement in which the coefficient of variation of the pitch is greater than 5%, preferably greater than 10%, and more preferably greater than 15%. The coefficient of variation is the ratio of the standard deviation to the mean. The non-constant pitch arrangement of the perforations may be an arrangement in which the coefficient of variation of the pitch is less than 40%, preferably less than 35%, and more preferably less than 30%.

[0028] In other words, a first pair of adjacent perforations may have a first distance between each other measured along the arc length of the peripheral wall, a second pair of adjacent perforations may have a second distance between each other measured along the arc length of the peripheral wall that is different from the first pair, and a third pair of adjacent perforations may have a third distance between each other measured along the arc length of the peripheral wall that is different from the first and second pairs. The first distance, second distance, and third distance may be different.

[0029] In one embodiment, more than half of the perforations may be located in one half of the peripheral wall of the ventilation zone and less than half of the perforations may be located in the remaining half of the peripheral wall of the ventilation zone. In a preferred embodiment, more than two-thirds of the perforations may be located in one half of the peripheral wall of the ventilation zone and less than one-third of the perforations may be located in the remaining half of the peripheral wall of the ventilation zone.

[0030] By having an asymmetric arrangement of perforations, the same quality of mixing between the ambient air and the air drawn through the rod of the aerosol-forming substrate can be achieved. However, asymmetric arrangement of perforations can facilitate manufacturing or promote increased manufacturing speed. More specifically, it is difficult to increase manufacturing speed while maintaining high-quality symmetric arrangement of perforations. It has been found that having asymmetric arrangement of perforations as described herein does not lead to a decrease in the quality of air mixing or a decrease in the quality of aerosol generation.

[0031] The perforations may penetrate the peripheral wall. The perforations may extend through the peripheral wall.

[0032] The peripheral wall may at least partially surround the ventilation zone. The peripheral wall may completely surround the ventilation zone. The hollow tubular shape of the ventilation zone may be facilitated by the peripheral wall of the ventilation zone. The peripheral wall may abut the ambient environment surrounding the aerosol-generating article. The peripheral wall may abut the hollow interior of the ventilation zone.

[0033] The thickness of the peripheral wall of the ventilation zone may be between 0.8 millimeters and 2.2 millimeters, more preferably between 1.2 millimeters and 1.8 millimeters, and most preferably about 1.5 millimeters.

[0034] The peripheral wall can be configured to provide a dimensionally stable ventilation zone. Due to the location of the perforations within the peripheral wall and the angle of the perforations, the perforations can have a length of 0.1 to 2.7 millimeters, preferably 0.8 to 2.4 millimeters, more preferably 1.2 to 2.0 millimeters, and most preferably about 1.7 millimeters.

[0035] The length of the perforations can affect the airflow through the perforations. The airflow can be directed by the shape of the perforations. The angle of the perforations described herein can cause turbulence as the air exits the perforations.

[0036] In one embodiment, all of the perforations are inclined in the same direction. All of the perforations may be inclined at the same angle relative to the radial direction. This may create a spiral turbulent airflow that enhances mixing of the ambient air with the air drawn through the rod of the aerosol-forming substrate.

[0037] The cross-sectional shape of one or more of the perforations may not vary along a central axis of the perforations. One or more of the perforations may have a cylindrical shape. One or more of the perforations may have a hollow cylindrical shape. One or more of the perforations may have a hollow tubular shape.

[0038] The perforations may be arranged in a row. The perforations may be arranged like pearls on a string. The row of perforations may be arranged in a ring shape. The row of perforations may be arranged in a ring shape with its centre on the central axis of the ventilation zone.

[0039] The distance between the perforations in the ventilation zone and the downstream end of the rod of the aerosol-generating substrate may be from 1 mm to 6 mm, preferably from 2 mm to 5 mm, more preferably from 3 mm to 4 mm.

[0040] The placement of the perforations in this region of the ventilation zone can improve aerosol generation by positioning the perforations so that optimized mixing is achieved between the ambient air drawn into the ventilation zone through the perforations and the air drawn through the rods of the aerosol-forming substrate into the perforations.

[0041] The distance between the perforations in the ventilation zone and the downstream end of the aerosol-generating article may be from 10 mm to 26 mm, preferably from 12 mm to 24 mm, more preferably from 14 mm to 22 mm, and most preferably from 16 mm to 20 mm.

[0042] The placement of perforations in this region of the ventilation zone can improve aerosol generation by having an optimized distance downstream of the perforations to allow cooling of the mixture of ambient air and air carrying the volatilized aerosol-forming substrate, allowing cooling of the mixture and subsequent aerosol formation.

[0043] The perforations may be configured to allow ambient air to be drawn into the ventilation zone.

[0044] The ratio of ambient air drawn into the ventilation zone through the perforations to air drawn into the ventilation zone through the rods of the aerosol-forming substrate may be between 5 percent and 75 percent, preferably between 20 percent and 65 percent, more preferably between 30 percent and 60 percent, more preferably between 40 percent and 55 percent, and most preferably 50 percent.

[0045] This ratio may improve aerosol formation by achieving thorough mixing of the air with the ambient air drawn through the rod of the aerosol-forming substrate. This ratio may improve aerosol formation by achieving optimized cooling of the air drawn through the rod of the aerosol-forming substrate by mixing this air with the ambient air.

[0046] The aerosol-generating article may further comprise a filter plug downstream of the ventilation zone. The resistance to withdrawal (RTD) of the filter plug may be between 5 millimeters HO and 80 millimeters HO, preferably between 10 millimeters HO and 65 millimeters HO, more preferably between 15 millimeters HO and 50 millimeters HO, more preferably between 20 millimeters HO and 40 millimeters HO, and most preferably 30 millimeters HO. Typically, the RTD may be measured by one of ISO 6565:2002 and Cholesta Recommended Method No. 41.

[0047] The overall resistance to withdrawal of the aerosol-generating article may be essentially determined by the resistance to withdrawal of the filter plug. The resistance to withdrawal of further components of the aerosol-generating article, particularly the ventilation zone, may be negligible compared to the resistance to withdrawal of the filter plug.

[0048] The present invention further relates to an aerosol generating system comprising an aerosol generating device having a cavity for receiving an aerosol-generating article as described herein.

[0049] The present invention further relates to a method of making an aerosol-generating article, the method comprising: providing a rod of aerosol-generating substrate; providing a ventilation zone downstream of the rod of the aerosol-generating substrate; forming non-circular perforations in the peripheral wall of the ventilation zone having an ellipticity, where the ellipticity is the ratio of the major diameter of the perforation divided by the minor diameter of the perforation, and is at least 1.5, and the thickness of the peripheral wall of the ventilation zone is between 0.1 millimeters and 2.5 millimeters.

[0050] The present invention further relates to a method of making an aerosol-generating article, the method comprising: providing a rod of aerosol-generating substrate; providing a ventilation zone downstream of the rod of the aerosol-generating substrate; forming non-circular perforations in the peripheral wall of the ventilation zone having an ellipticity, where the ellipticity is the ratio of the major diameter of the perforation divided by the minor diameter of the perforation, and is at least 1.5, and the thickness of the peripheral wall of the ventilation zone is between 0.1 millimeters and 2.5 millimeters.

[0051] The term "aerosol-generating article" is used herein to mean an article in which an aerosol-generating substrate is heated to generate an inhalable aerosol for delivery to a consumer. As used herein, the term "aerosol-generating substrate" means a substrate that has the ability to release volatile compounds upon heating to generate an aerosol.

[0052] As used herein, the term "aerosol-generating device" refers to a device that includes a heater element that interacts with an aerosol-generating substrate of an aerosol-generating article to generate an aerosol.

[0053] As used herein in connection with the present invention, the term "rod" is used to denote a generally cylindrical element of substantially circular, oval or elliptical cross section.

[0054] As used herein, the term "longitudinal" refers to a direction corresponding to the major longitudinal axis of the aerosol-generating article extending between the upstream and downstream ends of the aerosol-generating article. As used herein, the terms "upstream" and "downstream" describe the relative positions of elements (or portions of elements) of the aerosol-generating article with respect to the direction in which aerosol is transported through the aerosol-generating article during use.

[0055] During use, air is drawn longitudinally through the aerosol-generating article. The term "transverse" refers to a direction perpendicular to the longitudinal axis. Any reference to a "cross section" of an aerosol-generating article or a component of an aerosol-generating article refers to a transverse cross section, unless otherwise specified.

[0056] The term "length" refers to the dimension of a component of an aerosol-generating article in its longitudinal direction. For example, it may be used to refer to the dimension of a rod or elongated tubular element in its longitudinal direction.

[0057] The aerosol-forming substrate may be a solid aerosol-forming substrate.

[0058] In certain preferred embodiments, the aerosol-forming substrate comprises homogenized plant material, preferably homogenized tobacco material.

[0059] As used herein, the term "homogenized plant material" encompasses any plant material formed by agglomeration of plant particles. For example, a sheet or web of homogenized tobacco material for the aerosol-forming substrate of the present invention may be formed by agglomerating particles of tobacco material obtained by grinding, crushing, or comminuting plant material and, optionally, one or more of tobacco lamina and tobacco stems. Homogenized plant material may be produced by casting, extrusion, a papermaking process, or any other suitable process known in the art.

[0060] The homogenized plant material may be provided in any suitable form. For example, the homogenized plant material may be in the form of one or more sheets. The term "sheet" as used herein with respect to the present invention describes a thin layer of material having a width and length that is significantly greater than its thickness.

[0061] The homogenized plant material may be in the form of a plurality of pellets or granules.

[0062] The homogenized plant material may be in the form of multiple strands, pieces, or fragments. As used herein, the term "strand" describes an elongated element of material having a length substantially greater than its width and thickness. The term "strand" should be considered to encompass pieces, fragments, and any other homogenized plant material having a similar morphology. Strands of homogenized plant material may be formed from a sheet of homogenized plant material, for example, by cutting or shredding, or by other methods, such as extrusion methods.

[0063] The tobacco particles may have a nicotine content of at least about 2.5 weight percent on a dry weight basis. More preferably, the tobacco particles may have a nicotine content of at least about 3 weight percent on a dry weight basis, even more preferably at least about 3.2 weight percent, even more preferably at least about 3.5 weight percent, and most preferably at least about 4 weight percent.

[0064] The aerosol-forming substrate may further comprise one or more aerosol formers. Upon volatilization, the aerosol formers may carry other vaporized compounds, such as nicotine and flavorants in the aerosol, that are released from the aerosol-forming substrate upon heating. Aerosol formers suitable for inclusion in the homogenized plant material are known in the art and include, but are not limited to, polyhydric alcohols (such as triethylene glycol, propylene glycol, 1,3-butanediol, and glycerol), esters of polyhydric alcohols (such as glycerol mono-, di-, or triacetate), and aliphatic esters of mono-, di-, or polycarboxylic acids (such as dimethyl dodecanedioate and tetradecanedioate).

[0065] The aerosol-forming substrate may have an aerosol-former content of from about 5 weight percent to about 30 weight percent on a dry weight basis, or from about 10 weight percent to about 25 weight percent on a dry weight basis, or from about 15 weight percent to about 20 weight percent on a dry weight basis.

[0066] For example, when the substrate is intended for use in an aerosol-generating article for an electrically-operated aerosol-generating system having a heating element, the aerosol former content may preferably be about 5 weight percent to about 30 weight percent on a dry weight basis.When the substrate is intended for use in an aerosol-generating article for an electrically-operated aerosol-generating system having a heating element, the aerosol former is preferably glycerol.

[0067] The aerosol-forming substrate may comprise a gel composition comprising an alkaloid compound, or a cannabinoid compound, or both an alkaloid compound and a cannabinoid compound. In a particularly preferred embodiment, the aerosol-forming substrate comprises a gel composition comprising nicotine.

[0068] Preferably, the gel composition comprises nicotine.

[0069] The aerosol-generating article may comprise a substrate wrapper at least partially surrounding the aerosol-forming substrate. The substrate wrapper may comprise one or more layers having the same length along the longitudinal axis of the aerosol-generating article. The substrate wrapper may have a thickness of 30 to 45 micrometers. However, it may be preferred that the substrate wrapper have a thickness of 50 micrometers or more.

[0070] The substrate wrapper may have a thickness of 60 micrometers or more, preferably 65 micrometers or more, more preferably 75 micrometers or more, more preferably 80 micrometers or more, more preferably 90 micrometers or more, more preferably 100 micrometers or more, more preferably 110 micrometers or more, more preferably 120 micrometers or more, more preferably 130 micrometers or more, more preferably 140 micrometers or more, more preferably 145 micrometers or more, more preferably 150 micrometers or more. The substrate wrapper may have a thickness of about 148 micrometers. The substrate wrapper may have a thickness of 143 micrometers to 153 micrometers. The substrate wrapper may have a thickness of 140 micrometers to 160 micrometers.

[0071] The orientation of the perforations according to the present invention may be preferred when the tobacco plug is thin compared to the outer diameter of the aerosol-generating article (i.e., when the aerosol-forming substrate rod has a relatively thin radial thickness). This is particularly true when the substrate wrapper is thick as described herein (i.e., when the substrate wrapper has a thickness of 50 micrometers or more). This may be because the airflow is linear and different mixing with the air coming from the vent may be required if the aerosol-generating substrate does not occupy the entire diameter of the stick.

[0072] The substrate wrapper may have a density of 800 kilograms per cubic meter or less.

[0073] Preferably, in an aerosol-generating article according to the invention, the susceptor is disposed within the rod of the aerosol-forming substrate and is in thermal contact with the aerosol-forming substrate. The susceptor is preferably an elongated susceptor.

[0074] As used herein with respect to this specification, the term "susceptor" refers to a material capable of converting electromagnetic energy into heat. When located within a varying electromagnetic field, induced eddy currents in the susceptor cause the susceptor to heat. The elongated susceptor is located in thermal contact with an aerosol-forming substrate, which is heated by the susceptor.

[0075] When used to describe a susceptor, the term "elongated" means that the susceptor has a length dimension that is greater than its width dimension or its thickness dimension, for example, greater than twice its width dimension or its thickness dimension.

[0076] The susceptor is preferably disposed substantially longitudinally within the rod, meaning that the length dimension of the elongated susceptor is aligned approximately parallel to the longitudinal direction of the rod, for example, within ±10 degrees of parallel to the longitudinal direction of the rod. In a desirable embodiment, the elongated susceptor may be positioned at a radially central location within the rod, extending along the longitudinal axis of the rod.

[0077] Preferably, the susceptor extends all the way to the downstream end of the rod of aerosol-generating article. In some embodiments, the susceptor may extend all the way to the upstream end of the rod of aerosol-generating article. In particularly preferred embodiments, the susceptor has substantially the same length as the rod of aerosol-forming substrate, extending from the upstream end of the rod to the downstream end of the rod.

[0078] The susceptor is preferably in the form of a pin, rod, strip or blade.

[0079] The length of the susceptor is preferably in the range of about 5 mm to about 15 mm (for example, about 6 mm to about 12 mm, or about 8 mm to about 10 mm).

[0080] The ratio between the length of the susceptor and the overall length of the aerosol-generating article substrate may be from about 0.2 to about 0.35.

[0081] The susceptor may be formed from any material that can be inductively heated to a temperature sufficient to generate an aerosol from the aerosol-forming substrate. Preferred susceptors include metal or carbon.

[0082] A preferred susceptor may include or consist of a ferromagnetic material (e.g., a ferromagnetic alloy, ferritic iron, or ferromagnetic steel or stainless steel). A suitable susceptor may be or include aluminum. A preferred susceptor may be formed from 400 series stainless steel, such as grade 410, or grade 420, or grade 430 stainless steel. Different materials dissipate different amounts of energy when placed in electromagnetic fields having similar values ​​of frequency and field strength.

[0083] Thus, the susceptor parameters, such as material type, length, width, and thickness, may all be modified to provide the desired power dissipation within a known electromagnetic field. Preferred susceptors may be heated to temperatures in excess of 250 degrees Celsius.

[0084] A suitable susceptor may include a non-metallic core having a metal layer disposed thereon (e.g., a metal track formed on the surface of a ceramic core). The susceptor may have a protective outer layer, such as a protective ceramic or glass layer, encapsulating the susceptor. The susceptor may also include a protective coating formed of glass, ceramic, or an inert metal formed over a core of susceptor material.

[0085] The susceptor is arranged in thermal contact with the aerosol-forming substrate, such that as the temperature of the susceptor increases, the aerosol-forming substrate is heated and an aerosol is formed. Preferably, the susceptor is arranged in direct physical contact with the aerosol-forming substrate, for example, within the aerosol-forming substrate.

[0086] The aerosol-generating article may further comprise a downstream section located downstream of the rod of the aerosol-forming substrate. The downstream section may include an intermediate hollow section including an aerosol-cooling element arranged in alignment with and downstream of the rod of the aerosol-forming substrate.

[0087] The downstream section may further include one or more downstream elements above the aerosol-cooling element. For example, the intermediate hollow section may further comprise a support element positioned immediately downstream of the rod of the aerosol-forming substrate, and the aerosol-cooling element may be located between the support element and the downstream end (or mouth end) of the aerosol-generating article. More specifically, the aerosol-cooling element may be positioned immediately downstream of the support element. In some preferred embodiments, the aerosol-cooling element may abut the support element. As described below, the downstream section may further include one or more elements above the intermediate hollow section at a position downstream of the intermediate hollow section.

[0088] The aerosol cooling element may comprise a hollow tubular segment defining a cavity extending entirely from the upstream end of the aerosol cooling element to the downstream end of the aerosol cooling element, and ventilation zones may be provided at locations along the hollow tubular segment.

[0089] As used herein, the term "hollow tubular segment" is used generally to mean an elongated element that defines a lumen or airflow passage along its longitudinal axis. In particular, the term "tubular" is used hereinafter with reference to a tubular element that has a substantially cylindrical cross-section and defines at least one airflow conduit that establishes uninterrupted fluid communication between the upstream end of the tubular element and the downstream end of the tubular element. However, it will be appreciated that alternative shapes (e.g., alternative cross-sectional shapes) of the tubular element may be possible.

[0090] In the context of the present invention, the hollow tubular segment provides an unrestricted flow channel. This means that the hollow tubular segment provides a negligible level of resistance to withdrawal (RTD). Therefore, the flow channel should not include any components that would impede the longitudinal air flow. Preferably, the flow channel is substantially empty.

[0091] The term "elongated" when used to describe an aerosol cooling element means that the aerosol cooling element has a length dimension that is greater than its width dimension or its diameter dimension, for example, more than twice its width dimension or its diameter dimension.

[0092] The inventors have discovered that satisfactory cooling of the aerosol stream generated upon heating of an aerosol-forming substrate and drawn through one of such aerosol-cooling elements can be achieved by providing ventilation zones at locations along the hollow tubular segment. Furthermore, the inventors have discovered that, as described in more detail below, it may be possible to counter the effects of increased aerosol dilution caused by entrainment of ventilation air into the article, particularly by locating ventilation zones at precisely defined locations along the length of the aerosol-cooling element, and preferably by utilizing hollow tubular segments having a predetermined peripheral wall thickness or internal volume.

[0093] Without wishing to be bound by theory, it is believed that the introduction of ventilated air rapidly reduces the temperature of the aerosol stream as it moves toward the mouthpiece segment, so that the ventilated air enters the aerosol stream relatively close to the upstream end of the aerosol-cooling element (i.e., close enough to the heat source in use, the susceptor extending into the rod of the aerosol-forming substrate), achieving dramatic cooling of the aerosol stream, which has a favorable effect on aerosol particle condensation and nucleation. As a result, the overall ratio of aerosol particle phase to aerosol vapor phase may be increased compared to existing non-vented aerosol-generating articles.

[0094] The aerosol cooling element is positioned substantially aligned with the rod. This means that the length dimension of the aerosol cooling element is positioned approximately parallel to the longitudinal direction of the rod and article, for example, within ±10 degrees of parallel to the longitudinal direction of the rod. In a preferred embodiment, the aerosol cooling element extends along the longitudinal axis of the rod. The longitudinal axis of the rod is preferably the same as the longitudinal axis of the aerosol-generating article. The longitudinal axis of the aerosol-generating article is preferably the same as the central axis of the aerosol-generating article.

[0095] The aerosol-cooling element preferably has an outer diameter approximately equal to the outer diameter of the rod of the aerosol-forming substrate and the outer diameter of the aerosol-generating article.

[0096] The aerosol cooling element may have an outer diameter of 5 millimeters to 12 millimeters, such as an outer diameter of 5 millimeters to 10 millimeters, or an outer diameter of 6 millimeters to 8 millimeters. In a preferred embodiment, the aerosol cooling element has an outer diameter of 7.2 millimeters plus or minus 10 percent.

[0097] Preferably, the hollow tubular segment of the aerosol cooling element has an inner diameter of at least about 2 millimeters. More preferably, the hollow tubular segment of the aerosol cooling element has an inner diameter of at least about 3.5 millimeters. Even more preferably, the hollow tubular segment of the aerosol cooling element has an inner diameter of at least about 5 millimeters.

[0098] The peripheral wall of the aerosol cooling element may have a thickness of less than about 2.5 millimeters, preferably less than 22 millimeters. In particularly preferred embodiments, the peripheral wall of the aerosol cooling element has a thickness of between 1.2 millimeters and 1.8 millimeters.

[0099] In one embodiment, the peripheral wall of the aerosol cooling element has a thickness of about 1.5 millimeters.

[0100] The aerosol cooling element may have a length of less than about 10 millimeters.

[0101] The aerosol cooling element may have a length of at least about 5 millimeters, preferably at least about 6 millimeters, and more preferably at least about 7 millimeters.

[0102] The aerosol cooling element may have a length of from about 5 millimeters to about 10 millimeters, preferably from about 6 millimeters to about 10 millimeters, and more preferably from about 7 millimeters to about 10 millimeters.

[0103] The aerosol cooling element can therefore have a relatively short length compared to aerosol cooling elements of prior art aerosol-generating articles. The reduction in the length of the aerosol cooling element is possible due to optimization of the effectiveness of the hollow tubular segments forming the aerosol cooling element in aerosol cooling and nucleation. The reduction in the length of the aerosol cooling element advantageously reduces the risk of deformation of the aerosol-generating article due to compression during use, since the aerosol cooling element typically has lower resistance to deformation than the mouthpiece. Furthermore, the reduction in the length of the aerosol cooling element can provide cost benefits to manufacturers, since the cost of hollow tubular segments is typically higher per unit length than the cost of other elements, such as the mouthpiece element.

[0104] The ratio between the length of the aerosol-cooling element and the length of the rod of the aerosol-forming substrate may be from about 0.25 to about 1.

[0105] Preferably, the ratio between the length of the aerosol-cooling element and the length of the rod of the aerosol-forming substrate is at least about 0.3, more preferably at least about 0.4, and even more preferably at least about 0.5. In a preferred embodiment, the ratio between the length of the aerosol-cooling element and the length of the rod of the aerosol-forming substrate is less than about 0.9, more preferably less than about 0.8, and even more preferably less than about 0.7.

[0106] The ratio between the length of the aerosol-cooling element and the length of the rod of the aerosol-forming substrate can be about 0.3 to about 0.9, preferably about 0.4 to about 0.9, and more preferably about 0.5 to about 0.9. In other embodiments, the ratio between the length of the aerosol-cooling element and the length of the rod of the aerosol-forming substrate is about 0.3 to about 0.8, preferably about 0.4 to about 0.8, and more preferably about 0.5 to about 0.8. The ratio between the length of the aerosol-cooling element and the length of the rod of the aerosol-forming substrate is about 0.3 to about 0.7, preferably about 0.4 to about 0.7, and more preferably about 0.5 to about 0.7.

[0107] The ratio between the length of the aerosol-cooling element and the length of the rod of the aerosol-forming substrate may be about 0.66.

[0108] The ratio between the length of the aerosol-cooling element and the overall length of the aerosol-generating article substrate may be from about 0.125 to about 0.375.

[0109] Preferably, the ratio between the length of the aerosol-cooling element and the total length of the aerosol-generating article substrate is at least about 0.13, more preferably at least about 0.14, and even more preferably at least about 0.15. The ratio between the length of the aerosol-cooling element and the total length of the aerosol-generating article substrate is preferably less than about 0.3, more preferably less than about 0.25, and even more preferably less than about 0.20.

[0110] The ratio between the length of the aerosol-cooling element and the overall length of the aerosol-generating article substrate is preferably about 0.13 to about 0.3, more preferably about 0.14 to about 0.3, and even more preferably about 0.15 to about 0.3. In another embodiment, the ratio between the length of the aerosol-cooling element and the overall length of the aerosol-generating article substrate is preferably about 0.13 to about 0.25, more preferably about 0.14 to about 0.25, and even more preferably about 0.15 to about 0.25. In a further embodiment, the ratio between the length of the aerosol-cooling element and the overall length of the aerosol-generating article substrate is preferably about 0.13 to about 0.2, more preferably about 0.14 to about 0.2, and even more preferably about 0.15 to about 0.2.

[0111] The ratio between the length of the aerosol-cooling element and the overall length of the aerosol-generating article substrate is about 0.18.

[0112] The length of the mouthpiece element is preferably at least 1 millimeter greater than the length of the aerosol cooling element, more preferably at least 2 millimeters greater than the length of the aerosol cooling element, and more preferably at least 3 millimeters greater than the length of the aerosol cooling element. Reducing the length of the aerosol cooling element as described above can advantageously allow for an increase in the length of other elements of the aerosol-generating article, such as the mouthpiece element. The potential technical benefits of providing a relatively long mouthpiece element are discussed above.

[0113] In aerosol-generating articles according to the present invention, the aerosol cooling element preferably has an average radial hardness of at least about 80 percent, more preferably at least about 85 percent, and even more preferably at least about 90 percent, such that the aerosol cooling element can provide the aerosol-generating article with the desired level of hardness.

[0114] If desired, the radial stiffness of the aerosol cooling element of an aerosol-generating article according to the present invention may be further increased by surrounding the aerosol cooling element with a stiff plug wrap, such as a plug wrap having a basis weight of at least about 80 grams per square meter (gsm), or at least about 100 gsm, or at least about 110 gsm.

[0115] The aerosol cooling element may be formed from any suitable material or combination of materials. For example, the aerosol cooling element may be formed from one or more materials selected from the group consisting of cellulose acetate, cardboard, crimped paper (such as crimped heat-resistant paper or crimped parchment paper), and polymeric materials (such as low-density polyethylene (LDPE)). Other suitable materials include polyhydroxyalkanoate (PHA) fibers.

[0116] In a preferred embodiment, the aerosol cooling element is formed from cellulose acetate.

[0117] The ventilation zone comprises a plurality of perforations through the peripheral wall of the aerosol cooling element. Preferably, the ventilation zone comprises at least one peripheral row of perforations. In some embodiments, the ventilation zone may comprise two peripheral rows of perforations. For example, the perforations may be formed online during the manufacture of the aerosol-generating article. Preferably, each peripheral row of perforations comprises 8 to 30 perforations. However, certain numbers of perforations, such as 5 to 15 perforations, 7 to 14 perforations, 9 to 13 perforations, 10 to 12 perforations, and especially 11 perforations, have been found to result in improved aerosol generation.

[0118] When the aerosol-generating article includes a bonded plug for attaching the aerosol cooling element to one or more other components of the aerosol-generating article, the ventilation zone preferably includes at least one corresponding circumferential row of perforations provided through a portion of the bonded plug wrap. These may be formed online during the manufacture of the smoking article. The peripheral row or rows of perforations provided through a portion of the bonded plug wrap are preferably substantially aligned with the row(s) of perforations through the peripheral wall of the aerosol cooling element. In some embodiments, the distance between the ventilation zone and the upstream end of the hollow tubular segment of the aerosol cooling element is at least about 1 millimeter. Preferably, the distance between the ventilation zone and the upstream end of the hollow tubular segment of the aerosol cooling element is at least about 2 millimeters. More preferably, the distance between the ventilation zone and the upstream end of the hollow tubular segment of the aerosol cooling element is at least about 3 millimeters.

[0119] In some embodiments, the distance between the ventilation zone and the upstream end of the hollow tubular segment of the aerosol cooling element is about 6 millimeters or less. Preferably, the distance between the ventilation zone and the upstream end of the hollow tubular segment of the aerosol cooling element is about 5 millimeters or less. More preferably, the distance between the ventilation zone and the upstream end of the hollow tubular segment of the aerosol cooling element is about 4 millimeters or less.

[0120] The distance between the ventilation zone and the mouth end of the aerosol-generating article is preferably at least about 10 millimeters. More preferably, the distance between the ventilation zone and the mouth end of the aerosol-generating article is at least about 12 millimeters. Even more preferably, the distance between the ventilation zone and the mouth end of the aerosol-generating article is at least about 16 millimeters.

[0121] Preferably, the distance between the ventilation zone and the mouth end of the aerosol-generating article is about 26 millimeters or less. More preferably, the distance between the ventilation zone and the mouth end of the aerosol-generating article is about 24 millimeters or less. Even more preferably, the distance between the ventilation zone and the mouth end of the aerosol-generating article is about 22 millimeters or less. In a particularly preferred embodiment, the distance between the ventilation zone and the mouth end of the aerosol-generating article is about 20 millimeters or less.

[0122] Preferably, the distance between the ventilation zone and the upstream end of the downstream section is at least about 6 millimeters. More preferably, the distance between the ventilation zone and the upstream end of the downstream section is at least about 8 millimeters. Even more preferably, the distance between the ventilation zone and the upstream end of the downstream section is at least about 10 millimeters.

[0123] Preferably, the distance between the ventilation zone and the upstream end of the downstream section is about 20 millimeters or less. More preferably, the distance between the ventilation zone and the upstream end of the downstream section is about 18 millimeters or less. Even more preferably, the distance between the ventilation zone and the upstream end of the downstream section is about 16 millimeters or less.

[0124] Preferably, the distance between the ventilation zone and the downstream end of the susceptor is at least about 6 millimeters. More preferably, the distance between the ventilation zone and the downstream end of the susceptor is at least about 8 millimeters. Even more preferably, the distance between the ventilation zone and the downstream end of the susceptor is at least about 10 millimeters.

[0125] The distance between the ventilation zone and the downstream end of the susceptor may be between 9 millimeters and 10 millimeters.

[0126] The distance between the ventilation zone and the downstream end of the aerosol-forming substrate may be between 9 millimeters and 10 millimeters.

[0127] Preferably, the distance between the ventilation zone and the downstream end of the susceptor is about 20 millimeters or less. More preferably, the distance between the ventilation zone and the downstream end of the susceptor is about 18 millimeters or less. Even more preferably, the distance between the ventilation zone and the downstream end of the susceptor is about 16 millimeters or less.

[0128] Aerosol-generating articles according to the present invention may have a breathability level of at least about 5 percent. The term "breathability level" may also be referred to as "breathability percentage."

[0129] The term "ventilation level" is used throughout this specification to mean the volume ratio of the airflow entering the aerosol-generating article through the ventilation zone (ventilation airflow) to the sum of the aerosol airflow and the ventilation airflow. The greater the ventilation level, the greater the dilution of the aerosol stream delivered to the consumer.

[0130] Aerosol-generating articles according to the present invention may preferably have a breathability level of at least about 10 percent, preferably at least about 15 percent, more preferably at least about 20 percent, more preferably at least about 30 percent, and most preferably at least about 40 percent. In particularly preferred embodiments, aerosol-generating articles according to the present invention have a breathability level of at least about 25 percent.

[0131] Preferably, the aerosol-generating article has a breathability level of less than about 75 percent, preferably less than about 65 percent, and more preferably less than about 60 percent.

[0132] Aerosol-generating articles according to the present invention preferably have a breathability level of about 45 percent or less, more preferably about 40 percent or less, and even more preferably about 35 percent or less.

[0133] In a particularly preferred embodiment, the aerosol-generating article has a breathability level of about 30 percent.

[0134] In particularly preferred embodiments, the aerosol-generating article has a breathability level of about 28 percent to about 42 percent. In some particularly preferred embodiments, the aerosol-generating article has a breathability level of about 30 percent.

[0135] Without wishing to be bound by theory, the inventors have found that the temperature reduction caused by admitting cooler outside air into the hollow tubular segment through the ventilation zone can have a beneficial effect on the nucleation and growth of aerosol particles.

[0136] The formation of aerosols from gaseous mixtures containing various chemical species depends on a delicate interplay between nucleation, evaporation, condensation, and even fusion, which accounts for changes in vapor concentration, temperature, and velocity fields. The so-called classical nucleation theory is based on the assumption that a fraction of molecules in the gas phase are large enough to remain coherent for a long time with a sufficient probability (e.g., a 50 / 50 chance). These molecules represent a certain kind of critical, threshold molecular cluster within the transient molecular aggregates, meaning that smaller molecular clusters generally tend to break down into the gas phase rather quickly, while larger clusters generally tend to grow. These critical clusters are identified as primary nucleation cores from which droplets are expected to grow due to the condensation of molecules from the vapor. It is assumed that freshly nucleated, virgin droplets emerge with a certain original diameter and may subsequently grow by several orders of magnitude. This may be facilitated and enhanced by the rapid cooling of the surrounding vapor, which induces condensation. In this regard, it is helpful to remember that evaporation and condensation are two aspects of one and the same mechanism: gas-liquid mass transfer. Evaporation involves the net mass transfer from the droplets to the gas phase, while condensation is the net mass transfer from the gas phase to the droplet phase. Evaporation (or condensation) causes the droplets to shrink (or grow), but the number of droplets remains the same.

[0137] In this scenario (when the scenario is further complicated by fusion phenomena), the temperature and rate of cooling may play an important role in determining how the system responds. In general, because the nucleation process is typically nonlinear, different cooling rates may lead to significantly different temperature behaviors with respect to the formation of the liquid phase (droplets). Without wishing to be bound by theory, it is hypothesized that cooling can cause a rapid increase in the number of condensed droplets, followed by a short-term, strong increase in this growth (nucleation burst). This nucleation burst appears to be more pronounced at lower temperatures. Furthermore, it appears that a faster cooling rate may favor the onset of early nucleation. In contrast, a decrease in the cooling rate appears to have a favorable effect on the final size that the aerosol droplets ultimately reach.

[0138] Thus, the rapid cooling induced by admitting ambient air into the hollow tubular segment through the ventilation zone can be used to favor favorable nucleation and growth of aerosol droplets. At the same time, however, admitting ambient air into the hollow tubular segment has the direct drawback of diluting the aerosol stream delivered to the consumer.

[0139] The inventors have surprisingly found that the dilution effect on the aerosol (which can be assessed, inter alia, by measuring the effect on the delivery of the aerosol former (e.g., glycerol) contained in the aerosol-forming substrate) is advantageously minimized at aeration levels within the aforementioned ranges. In particular, aeration levels of 20 percent to 70 percent, preferably 25 percent to 50 percent, and even more preferably 28 to 42 percent, have been found to lead to particularly satisfactory glycerin delivery values. At the same time, the degree of nucleation, and consequently, the delivery of nicotine and aerosol former (e.g., glycerol), are enhanced.

[0140] The inventors have surprisingly found that the favorable effect of enhanced nucleation promoted by the rapid cooling induced by the introduction of ventilation air into the article can significantly counteract the undesirable effects of dilution, and therefore satisfactory aerosol delivery values ​​are consistently achieved by aerosol-generating articles in accordance with the present invention.

[0141] This is particularly advantageous for "short" aerosol-generating articles, such as those in which the length of the rod of aerosol-forming substrate is less than about 40 millimeters, preferably less than 25 millimeters, and even more preferably less than 20 millimeters, or the total length of the aerosol-generating article is less than about 70 millimeters, preferably less than about 60 millimeters, and even more preferably less than 50 millimeters. As will be appreciated, in such aerosol-generating articles, there is little time and space for aerosol formation and for the particle phase of the aerosol to become available for delivery to the consumer.

[0142] Furthermore, because the vented hollow tubular element does not substantially contribute to the overall RTD of the aerosol-generating article, the overall RTD of the article can be advantageously fine-tuned in an aerosol-generating article according to the present invention by adjusting the length and density of the rod of the aerosol-forming substrate, or the length and density of the segment of filtering material that optionally forms part of the mouthpiece, or the length and density of the segment of filtering material provided upstream of the aerosol-forming substrate and susceptor. Therefore, aerosol-generating articles having a predetermined RTD can be consistently and precisely manufactured, thereby providing a satisfactory level of RTD for the consumer, even in the presence of ventilation.

[0143] In an aerosol-generating article according to the present invention, the overall RTD of the article depends essentially on the RTD of the rod and, optionally, the RTD of the mouthpiece and / or upstream plug, since the hollow tubular segments of the aerosol-cooling element and the hollow tubular segments of the support element are substantially empty and therefore only make a substantially small contribution to the overall RTD of the aerosol-generating article.

[0144] In practice, the hollow tubular segment of the aerosol cooling element may be adapted to generate an RTD in the range of approximately 0 millimeters of HO (approximately 0 Pa) to approximately 20 millimeters of HO (approximately 200 Pa). Preferably, the hollow tubular segment of the aerosol cooling element is adapted to generate an RTD in the range of approximately 0 millimeters of HO (approximately 0 Pa) to approximately 10 millimeters of HO (approximately 100 Pa).

[0145] The downstream section of the aerosol-generating article according to the present invention preferably comprises an intermediate hollow section including a support element aligned with and arranged downstream of the rod of the aerosol-forming substrate. In particular, the support element may be located immediately downstream of the rod of the aerosol-forming substrate or adjacent to the rod of the aerosol-forming substrate.

[0146] The support element may be formed from any suitable material or combination of materials. For example, the support element may be formed from one or more materials selected from the group consisting of cellulose acetate, cardboard, crimped paper (such as crimped heat-resistant paper or crimped parchment paper), and polymeric materials (such as low-density polyethylene (LDPE)). In a preferred embodiment, the support element is formed from cellulose acetate. Other suitable materials include polyhydroxyalkanoate (PHA) fibers.

[0147] The support element may comprise a hollow tubular element. In a preferred embodiment, the support element comprises a hollow cellulose acetate tube.

[0148] The support element is positioned substantially aligned with the rod, meaning that the length dimension of the support element is positioned approximately parallel to the longitudinal direction of the rod and article, for example, within ±10 degrees of parallel to the longitudinal direction of the rod. In a preferred embodiment, the support element extends along the longitudinal axis of the rod.

[0149] The support element preferably has an outer diameter approximately equal to the outer diameter of the rod of the aerosol-forming substrate and the outer diameter of the aerosol-generating article.

[0150] The support element may have an outer diameter of 5 millimeters to 12 millimeters, such as an outer diameter of 5 millimeters to 10 millimeters, or an outer diameter of 6 millimeters to 8 millimeters. In a preferred embodiment, the support element has an outer diameter of 7.2 millimeters ±10 percent. The support element may have a length of 5 millimeters to 15 millimeters. In a preferred embodiment, the support element has a length of 8 millimeters.

[0151] The peripheral wall of the support element may have a thickness of at least 1 millimeter, preferably at least about 1.5 millimeters, and more preferably at least about 2 millimeters.

[0152] The support element may have a length of from about 5 millimeters to about 15 millimeters.

[0153] Preferably, the support element has a length of at least about 6 millimeters, and more preferably at least about 7 millimeters.

[0154] In preferred embodiments, the support element has a length of less than about 12 millimeters, more preferably less than about 10 millimeters.

[0155] In some embodiments, the support element has a length of about 5 millimeters to about 15 millimeters, preferably about 6 millimeters to about 15 millimeters, and more preferably about 7 millimeters to about 15 millimeters. In other embodiments, the support element has a length of about 5 millimeters to about 12 millimeters, preferably about 6 millimeters to about 12 millimeters, and more preferably about 7 millimeters to about 12 millimeters. In further embodiments, the support element has a length of about 5 millimeters to about 10 millimeters, preferably about 6 millimeters to about 10 millimeters, and more preferably about 7 millimeters to about 10 millimeters.

[0156] In a preferred embodiment, the support element has a length of about 8 millimeters.

[0157] The ratio between the length of the support element and the length of the rod of the aerosol-forming substrate may be from about 0.25 to about 1.

[0158] Preferably, the ratio between the length of the support element and the length of the rod of the aerosol-forming substrate is at least about 0.3, more preferably at least about 0.4, and even more preferably at least about 0.5. In a preferred embodiment, the ratio between the length of the support element and the length of the rod of the aerosol-forming substrate is less than about 0.9, more preferably less than about 0.8, and even more preferably less than about 0.7.

[0159] In some embodiments, the ratio between the length of the support element and the length of the rod of the aerosol-forming substrate is about 0.3 to about 0.9, preferably about 0.4 to about 0.9, and more preferably about 0.5 to about 0.9. In other embodiments, the ratio between the length of the support element and the length of the rod of the aerosol-forming substrate is about 0.3 to about 0.8, preferably about 0.4 to about 0.8, and more preferably about 0.5 to about 0.8. In further embodiments, the ratio between the length of the support element and the length of the rod of the aerosol-forming substrate is about 0.3 to about 0.7, preferably about 0.4 to about 0.7, and more preferably about 0.5 to about 0.7.

[0160] In a particularly preferred embodiment, the ratio between the length of the support element and the length of the rod of the aerosol-forming substrate is about 0.66.

[0161] The ratio between the length of the support element and the overall length of the aerosol-generating article substrate may be from about 0.125 to about 0.375.

[0162] The ratio between the length of the support element and the overall length of the aerosol-generating article substrate is at least about 0.13, more preferably at least about 0.14, and even more preferably at least about 0.15. The ratio between the length of the support element and the overall length of the aerosol-generating article substrate is preferably less than about 0.3, more preferably less than about 0.25, and even more preferably less than about 0.20.

[0163] In some embodiments, the ratio between the length of the support element and the overall length of the aerosol-generating article substrate is preferably about 0.13 to about 0.3, more preferably about 0.14 to about 0.3, and even more preferably about 0.15 to about 0.3. In other embodiments, the ratio between the length of the support element and the overall length of the aerosol-generating article substrate is preferably about 0.13 to about 0.25, more preferably about 0.14 to about 0.25, and even more preferably about 0.15 to about 0.25. In further embodiments, the ratio between the length of the support element and the overall length of the aerosol-generating article substrate is preferably about 0.13 to about 0.2, more preferably about 0.14 to about 0.2, and even more preferably about 0.15 to about 0.2.

[0164] In a particularly preferred embodiment, the ratio between the length of the support element and the overall length of the aerosol-generating article substrate is about 0.18.

[0165] In aerosol-generating articles according to the present invention, the support element preferably has an average radial hardness of at least about 80 percent, more preferably at least about 85 percent, and even more preferably at least about 90 percent, such that the support element can provide the aerosol-generating article with the desired level of hardness.

[0166] If desired, the radial stiffness of the support element of an aerosol-generating article according to the present invention may be further increased by surrounding the support element with a stiff plug wrap, such as a plug wrap having a basis weight of at least about 80 grams per square meter (gsm), or at least about 100 gsm, or at least about 110 gsm.

[0167] When inserting an aerosol-generating article according to the present invention into an aerosol-generating device to heat the aerosol-forming substrate, the user may need to apply some force to overcome the resistance to insertion of the aerosol-forming substrate of the aerosol-generating article. This may damage one or both of the aerosol-generating article and the aerosol-generating device. In addition, applying force when inserting the aerosol-generating article into the aerosol-generating device may cause the aerosol-forming substrate within the aerosol-generating article to become misaligned. This may result in the heating element of the aerosol-generating device not being properly aligned with the susceptor provided in the aerosol-forming substrate, leading to uneven and inefficient heating of the aerosol-forming substrate of the aerosol-generating article. Advantageously, the support element is configured to resist downstream movement of the aerosol-forming substrate during insertion of the article into the aerosol-generating device.

[0168] In an aerosol-generating article according to the present invention, the overall RTD of the article depends essentially on the RTD of the rod and, optionally, the RTD of the mouthpiece and / or upstream plug, since the hollow tubular segments of the aerosol-cooling element and the hollow tubular segments of the support element are substantially empty and therefore only make a substantially small contribution to the overall RTD of the aerosol-generating article.

[0169] In practice, the hollow tubular segment of the support element may be adapted to generate an RTD in the range of approximately 0 millimeters of HO (approximately 0 Pa) to approximately 20 millimeters of HO (approximately 200 Pa). Preferably, the hollow tubular segment of the support element is adapted to generate an RTD in the range of approximately 0 millimeters of HO (approximately 0 Pa) to approximately 10 millimeters of HO (approximately 100 Pa).

[0170] In some embodiments where the downstream section comprises both a support element comprising a first hollow tubular segment and an aerosol cooling element comprising a second hollow tubular segment, the support element and the aerosol cooling element together defining an intermediate hollow section, the inner diameter (D STS ) is preferably equal to the inner diameter (D FTS ) is greater than

[0171] More specifically, the inner diameter (D STS ) and the inner diameter (D FTS ) is preferably at least about 1.25. More preferably, the ratio between the inner diameter (D STS ) and the inner diameter (D FTS ) is preferably at least about 1.3. Even more preferably, the ratio between the inner diameter (D STS ) and the inner diameter (D FTS ) is preferably at least about 1.4. In particularly preferred embodiments, the ratio between the inner diameter (D STS ) and the inner diameter (D FTS ) is at least about 1.5, more preferably at least about 1.6.

[0172] The inner diameter (D STS ) and the inner diameter (D FTS ) is preferably about 2.5 or less. More preferably, the ratio between the inner diameter (D STS) and the inner diameter (D FTS ) is preferably about 2.25 or less. Even more preferably, the ratio between the inner diameter (D STS ) and the inner diameter (D FTS ) is preferably about 2 or less.

[0173] In those embodiments in which the article further comprises an elongated susceptor longitudinally disposed within the aerosol-forming substrate, the inner diameter (D FTS The ratio between the inner diameter (D ) of the first hollow tubular segment and the width of the susceptor is preferably at least about 0.2. FTS ) and the width of the susceptor is at least about 0.3. Even more preferably, the ratio between the inner diameter (D FTS ) and the width of the susceptor is at least about 0.4.

[0174] Additionally or alternatively, the inner diameter (D STS The ratio between the inner diameter (D ) of the second hollow tubular segment and the width of the susceptor is preferably at least about 0.2. STS ) and the width of the susceptor is at least about 0.5. Even more preferably, the ratio between the inner diameter (D STS ) and the width of the susceptor is at least about 0.8.

[0175] Preferably, the ratio between the volume of the cavity of the first hollow tubular segment and the volume of the cavity of the second hollow tubular segment is at least about 0.1. More preferably, the ratio between the volume of the cavity of the first hollow tubular segment and the volume of the cavity of the second hollow tubular segment is at least about 0.2. Even more preferably, the ratio between the volume of the cavity of the first hollow tubular segment and the volume of the cavity of the second hollow tubular segment is at least about 0.3.

[0176] Preferably, the ratio between the volume of the cavity of the first hollow tubular segment and the volume of the cavity of the second hollow tubular segment is about 0.9 or less. More preferably, the ratio between the volume of the cavity of the first hollow tubular segment and the volume of the cavity of the second hollow tubular segment is about 0.7 or less. Even more preferably, the ratio between the volume of the cavity of the first hollow tubular segment and the volume of the cavity of the second hollow tubular segment is about 0.5 or less.

[0177] In a preferred embodiment, the downstream section of an aerosol-generating article according to the present invention comprises an intermediate hollow section having both an aerosol-cooling element as described above and a support element as described above.

[0178] The length of the mouthpiece element is preferably at least 0.4 times the total length of the intermediate hollow section, more preferably at least 0.5 times the length of the intermediate hollow section, more preferably at least 0.6 times the length of the intermediate hollow section, more preferably at least 0.7 times the length of the intermediate hollow section.

[0179] The downstream section of the aerosol-generating article of the present invention preferably comprises a mouthpiece element. The mouthpiece element is preferably located at the downstream or mouth end of the aerosol-generating article. The mouthpiece element preferably comprises at least one mouthpiece filter segment for filtering the aerosol generated from the aerosol-forming substrate. For example, the mouthpiece element may comprise one or more segments of a fibrous filtering material. Suitable fibrous filtering materials are known to those skilled in the art. It is particularly preferred that the at least one mouthpiece filter segment comprises a cellulose acetate filter segment formed from cellulose acetate tow.

[0180] In certain preferred embodiments, the mouthpiece element comprises a single mouthpiece filter segment. In alternative embodiments, the mouthpiece element comprises two or more axially aligned mouthpiece filter segments abutting one another in an end-to-end relationship.

[0181] In certain embodiments of the present invention, the downstream section may comprise a mouth-end recess at a downstream end downstream of the mouthpiece element as described above. The mouth-end recess may be defined by a hollow tubular element provided at the downstream end of the mouthpiece. Alternatively, the mouth-end recess may be defined by an outer wrapper of the mouthpiece element, the outer wrapper extending in a downstream direction from the mouthpiece element.

[0182] The mouthpiece element may optionally include a flavorant, which may be provided in any suitable form, for example, the mouthpiece element may include one or more capsules, flavorant beads or granules, or one or more flavor-loaded threads or filaments.

[0183] In the aerosol-generating article according to the invention, the mouthpiece element forms part of the downstream section and is therefore located downstream of the rod of the aerosol-forming substrate.

[0184] In certain preferred embodiments, the downstream section of the aerosol-generating article further comprises a support element located immediately downstream of the rod of the aerosol-forming substrate. The mouthpiece element is located downstream of the support element. Preferably, the downstream section further comprises an aerosol-cooling element located immediately downstream of the support element. The mouthpiece element is preferably located downstream of both the support element and the aerosol-cooling element. Particularly preferably, the mouthpiece element is located immediately downstream of the aerosol-cooling element. As an example, the mouthpiece element may abut against the downstream end of the aerosol-cooling element.

[0185] Preferably, the mouthpiece element has a low particle filtration efficiency.

[0186] Preferably, the mouthpiece is formed from a segment of fibrous filtering material.

[0187] The mouthpiece element is preferably surrounded by plug wrap. The mouthpiece element is preferably non-ventilated so that air does not enter the aerosol-generating article along the mouthpiece element.

[0188] The mouthpiece element is preferably connected to one or more of the adjacent upstream components of the aerosol-generating article by a tip wrapper.

[0189] Preferably, the mouthpiece element has an RTD of less than about 25 millimeters HO. More preferably, the mouthpiece element has an RTD of less than about 20 millimeters HO. Even more preferably, the mouthpiece element has an RTD of less than about 15 millimeters HO.

[0190] RTD values ​​of about 10 millimeters HO to about 15 millimeters HO are particularly preferred, as a mouthpiece element having one such RTD is expected to contribute minimally to the overall RTD of the aerosol-generating article, thereby providing substantially no filtering effect on the aerosol delivered to the consumer.

[0191] The mouthpiece element preferably has an outer diameter approximately equal to the outer diameter of the aerosol-generating article. The mouthpiece element may have an outer diameter of about 5 millimeters to about 10 millimeters, or about 6 millimeters to about 8 millimeters. In a preferred embodiment, the mouthpiece element has an outer diameter of about 7.2 millimeters.

[0192] The mouthpiece element preferably has a length of at least about 5 millimeters, more preferably at least about 8 millimeters, more preferably at least about 10 millimeters. Alternatively, or additionally, the mouthpiece element preferably has a length of less than about 25 millimeters, more preferably less than about 20 millimeters, more preferably less than about 15 millimeters.

[0193] In some embodiments, the mouthpiece element preferably has a length of about 5 millimeters to about 25 millimeters, more preferably about 8 millimeters to about 25 millimeters, and even more preferably about 10 millimeters to about 25 millimeters. In other embodiments, the mouthpiece element preferably has a length of about 5 millimeters to about 10 millimeters, more preferably about 8 millimeters to about 20 millimeters, and even more preferably about 10 millimeters to about 20 millimeters. In further embodiments, the mouthpiece element preferably has a length of about 5 millimeters to about 15 millimeters, more preferably about 8 millimeters to about 15 millimeters, and even more preferably about 10 millimeters to about 15 millimeters.

[0194] For example, the mouthpiece element may have a length of about 5 millimeters to about 25 millimeters, or about 8 millimeters to about 20 millimeters, or about 10 millimeters to about 15 millimeters. In a preferred embodiment, the mouthpiece element has a length of approximately 12 millimeters.

[0195] In certain preferred embodiments of the present invention, the mouthpiece element has a length of at least 10 millimeters. In such embodiments, the mouthpiece element is therefore relatively long compared to mouthpiece elements provided in prior art articles. Providing a relatively long mouthpiece element in the aerosol-generating article of the present invention can provide several benefits to consumers. The mouthpiece element is typically more resilient to deformation or better adapted to recover its original shape after deformation than other elements that may be provided downstream of the aerosol-forming substrate rod, such as an aerosol cooling element or a support element. Therefore, increasing the length of the mouthpiece element has been found to provide an improved grip by the consumer and facilitate insertion of the aerosol-generating article into a heating device. Longer mouthpieces can be additionally used to provide higher levels of filtration and removal of undesirable aerosol components, such as phenol, thereby delivering a higher quality aerosol. Furthermore, the use of longer mouthpiece elements allows for more complex mouthpieces to be provided, as there is more space for incorporating mouthpiece components such as capsules, threads, and restrictors.

[0196] In particularly preferred embodiments of the present invention, a mouthpiece having a length of at least 10 millimeters is combined with a relatively short aerosol cooling element, for example, an aerosol cooling element having a length of less than 10 millimeters. This combination has been found to reduce the risk of deformation of the aerosol cooling element during use and provide a more rigid mouthpiece, contributing to a more efficient puffing action by the consumer.

[0197] The ratio between the length of the mouthpiece element and the length of the rod of the aerosol-forming substrate may be from about 0.5 to about 1.5.

[0198] Preferably, the ratio between the length of the mouthpiece element and the length of the rod of the aerosol-forming substrate is at least about 0.6, more preferably at least about 0.7, and even more preferably at least about 0.8. In preferred embodiments, the ratio between the length of the mouthpiece element and the length of the rod of the aerosol-forming substrate is less than about 1.4, more preferably less than about 1.3, and even more preferably less than about 1.2.

[0199] In some embodiments, the ratio between the length of the mouthpiece element and the length of the rod of the aerosol-forming substrate is about 0.6 to about 1.4, preferably about 0.7 to about 1.4, and more preferably about 0.8 to about 1.4. In other embodiments, the ratio between the length of the mouthpiece element and the length of the rod of the aerosol-forming substrate is about 0.6 to about 1.3, preferably about 0.7 to about 1.3, and more preferably about 0.8 to about 1.3. In further embodiments, the ratio between the length of the mouthpiece element and the length of the rod of the aerosol-forming substrate is about 0.6 to about 1.2, preferably about 0.7 to about 1.2, and more preferably about 0.8 to about 1.2.

[0200] In a particularly preferred embodiment, the ratio between the length of the mouthpiece element and the length of the rod of the aerosol-forming substrate is about 1.

[0201] The ratio between the length of the mouthpiece element and the overall length of the aerosol-generating article substrate may be from about 0.2 to about 0.35.

[0202] Preferably, the ratio between the length of the mouthpiece element and the overall length of the aerosol-generating article substrate is at least about 0.22, more preferably at least about 0.24, and even more preferably at least about 0.26. The ratio between the length of the mouthpiece element and the overall length of the aerosol-generating article substrate is preferably less than about 0.34, more preferably less than about 0.32, and even more preferably less than about 0.3.

[0203] In some embodiments, the ratio between the length of the mouthpiece element and the overall length of the aerosol-generating article substrate is preferably about 0.22 to about 0.34, more preferably about 0.24 to about 0.34, and even more preferably about 0.26 to about 0.34. In other embodiments, the ratio between the length of the mouthpiece element and the overall length of the aerosol-generating article substrate is preferably about 0.22 to about 0.32, more preferably about 0.24 to about 0.32, and even more preferably about 0.26 to about 0.32. In further embodiments, the ratio between the length of the mouthpiece element and the overall length of the aerosol-generating article substrate is preferably about 0.22 to about 0.3, more preferably about 0.24 to about 0.3, and even more preferably about 0.26 to about 0.3.

[0204] In a particularly preferred embodiment, the ratio between the length of the mouthpiece element and the overall length of the aerosol-generating article substrate is about 0.27.

[0205] The aerosol-generating article may further comprise an upstream section at a location upstream of the rod of aerosol-forming substrate. The upstream section may comprise one or more upstream elements. In some embodiments, the upstream section may comprise an upstream element located immediately upstream of the rod of aerosol-forming substrate.

[0206] The aerosol-generating article of the present invention preferably includes an upstream element located upstream of and adjacent to the aerosol-forming substrate, the upstream section including at least one upstream element. The upstream element advantageously prevents direct physical contact with the upstream end of the aerosol-forming substrate. In particular, if the aerosol-forming substrate includes a susceptor element, the upstream element may prevent direct physical contact with the upstream end of the susceptor element. This helps to prevent displacement or deformation of the susceptor element during handling or transportation of the aerosol-generating article. This in turn helps to fix the shape and position of the susceptor element. Furthermore, the presence of the upstream element helps to prevent any loss of the substrate, which may be advantageous, for example, when the substrate contains particulate plant material.

[0207] The upstream element may also provide an improved appearance to the upstream end of the aerosol-generating article. Additionally, if desired, the upstream element may be used to provide information about the aerosol-generating article, such as the brand, flavor, content, or details of the aerosol-generating device in which the article is intended to be used.

[0208] The upstream element may be a porous plug element. Preferably, the porous plug element does not alter the draw resistance of the aerosol-generating article. Preferably, the upstream element has a porosity of at least about 50 percent in the longitudinal direction of the aerosol-generating article. More preferably, the upstream element has a porosity of between about 50 percent and about 90 percent in the longitudinal direction. The longitudinal porosity of the upstream element is defined as the ratio of the cross-sectional area of ​​the material forming the upstream element to the internal cross-sectional area of ​​the aerosol-generating article at the location of the upstream element.

[0209] The upstream element may be made of a porous material or may comprise a plurality of openings, which may be achieved, for example, by laser drilling, and the plurality of openings are preferably homogeneously distributed across the cross section of the upstream element.

[0210] The porosity or permeability of the upstream element may be advantageously varied to provide a desired overall resistance to withdrawal of the aerosol-generating article.

[0211] Preferably, the RTD of the upstream element is at least about 5 millimeters of H2O. More preferably, the RTD of the upstream element is at least about 10 millimeters of H2O. Even more preferably, the RTD of the upstream element is at least about 15 millimeters of H2O. In a particularly preferred embodiment, the RTD of the upstream element is at least about 20 millimeters of H2O.

[0212] The RTD of the upstream element is preferably about 80 millimeters H2O or less. More preferably, the RTD of the upstream element is about 60 millimeters H2O or less. Even more preferably, the RTD of the upstream element is about 40 millimeters H2O or less.

[0213] In some embodiments, the RTD of the upstream element is between about 5 millimeters HO and about 80 millimeters HO, preferably between about 10 millimeters HO and about 80 millimeters HO, more preferably between about 15 millimeters HO and about 80 millimeters HO, and even more preferably between about 20 millimeters HO and about 80 millimeters HO. In other embodiments, the RTD of the upstream element is between about 5 millimeters HO and about 60 millimeters HO, preferably between about 10 millimeters HO and about 60 millimeters HO, more preferably between about 15 millimeters HO and about 60 millimeters HO, and even more preferably between about 20 millimeters HO and about 60 millimeters HO. In further embodiments, the RTD of the upstream element is between about 5 millimeters HO and about 40 millimeters HO, preferably between about 10 millimeters HO and about 40 millimeters HO, more preferably between about 15 millimeters HO and about 40 millimeters HO, and even more preferably between about 20 millimeters HO and about 40 millimeters HO.

[0214] In alternative embodiments, the upstream element may be formed from a material that is impermeable to air. In such embodiments, the aerosol-generating article may be configured to allow air to enter the rod of aerosol-forming substrate via suitable venting means provided in the wrapper.

[0215] The upstream element can be made of any material suitable for use in an aerosol-generating article. The upstream element may be made of the same material as that used in one of the other components of the aerosol-generating article, such as the mouthpiece, cooling element, or support element. Suitable materials for forming the upstream element include filter material, ceramic, polymeric material, cellulose acetate, cardboard, zeolite, or an aerosol-forming substrate. The upstream element is preferably formed from a plug of cellulose acetate.

[0216] The upstream element is preferably formed from a heat resistant material, for example, a material that can withstand temperatures up to 350 degrees Celsius, to ensure that the upstream element is not adversely affected by the heating means for heating the aerosol-forming substrate.

[0217] The upstream element preferably has a diameter approximately equal to the diameter of the aerosol-generating article.

[0218] Preferably, the upstream element has a length of about 1 millimeter to about 10 millimeters, more preferably about 3 millimeters to about 8 millimeters, and even more preferably about 4 millimeters to about 6 millimeters. In a particularly preferred embodiment, the upstream element has a length of about 5 millimeters. The length of the upstream element can be advantageously varied to provide a desired overall length for the aerosol-generating article. For example, if it is desired to reduce the length of one of the other components of the aerosol-generating article, the length of the upstream element can be increased to maintain the same overall length for the article.

[0219] The upstream element preferably has a substantially homogeneous structure. For example, the upstream element may be substantially homogeneous in texture and appearance. The upstream element may, for example, have a continuous, regular surface over its entire cross section. The upstream element may, for example, not have any discernible symmetry.

[0220] The upstream element is preferably surrounded by a wrapper that is preferably a stiff plug wrap, such as a plug wrap having a basis weight of at least about 80 grams per square meter (gsm), or at least about 100 gsm, or at least about 110 gsm, to provide structural rigidity to the upstream element.

[0221] The aerosol-generating article may have a length of from about 35 millimeters to about 100 millimeters.

[0222] Preferably, the overall length of an aerosol-generating article according to the present invention is at least about 38 millimeters. More preferably, the overall length of an aerosol-generating article according to the present invention is at least about 40 millimeters. Even more preferably, the overall length of an aerosol-generating article according to the present invention is at least about 42 millimeters.

[0223] Preferably, the overall length of an aerosol-generating article according to the present invention is 70 mm or less, more preferably 60 mm or less, and even more preferably 50 mm or less.

[0224] In some embodiments, the total length of the aerosol-generating article is preferably between about 38 millimeters and about 70 millimeters, more preferably between about 40 millimeters and about 70 millimeters, and even more preferably between about 42 millimeters and about 70 millimeters. In other embodiments, the total length of the aerosol-generating article is preferably between about 38 millimeters and about 60 millimeters, more preferably between about 40 millimeters and about 60 millimeters, and even more preferably between about 42 millimeters and about 60 millimeters. In further embodiments, the total length of the aerosol-generating article is preferably between about 38 millimeters and about 50 millimeters, more preferably between about 40 millimeters and about 50 millimeters, and even more preferably between about 42 millimeters and about 50 millimeters. In an exemplary embodiment, the total length of the aerosol-generating article is about 45 millimeters.

[0225] The aerosol-generating article has an outer diameter of at least 5 millimeters. Preferably, the aerosol-generating article has an outer diameter of at least 6 millimeters. More preferably, the aerosol-generating article has an outer diameter of at least 7 millimeters.

[0226] Preferably, the aerosol-generating article has an outer diameter of about 12 millimeters or less. More preferably, the aerosol-generating article has an outer diameter of about 10 millimeters or less. Even more preferably, the aerosol-generating article has an outer diameter of about 8 millimeters or less.

[0227] In some embodiments, the aerosol-generating article has an outer diameter of about 5 mm to about 12 mm, preferably about 6 mm to about 12 mm, and more preferably about 7 mm to about 12 mm. In other embodiments, the aerosol-generating article has an outer diameter of about 5 mm to about 10 mm, preferably about 6 mm to about 10 mm, and more preferably about 7 mm to about 10 mm. In further embodiments, the aerosol-generating article has an outer diameter of about 5 mm to about 8 mm, preferably about 6 mm to about 8 mm, and more preferably about 7 mm to about 8 mm.

[0228] In certain preferred embodiments of the present invention, the diameter of the aerosol-generating article at the mouth end (D ME ) is the diameter of the aerosol-generating article at its distal end (D DE ) is (preferably) greater than the ratio between the diameter of the aerosol-generating article at its mouth end and the diameter of the aerosol-generating article at its distal end (D ME / D DE ) is (preferably) at least about 1.005.

[0229] Preferably, the ratio between the diameter of the aerosol-generating article at the oral end and the diameter of the aerosol-generating article at the distal end (D ME / D DE ) is (preferably) at least about 1.01. More preferably, the ratio between the diameter of the aerosol-generating article at the oral end and the diameter of the aerosol-generating article at the distal end (D ME / D DE ) is at least about 1.02. Even more preferably, the ratio between the diameter of the aerosol-generating article at the oral end and the diameter of the aerosol-generating article at the distal end (D ME / DDE ) is at least about 1.05.

[0230] The ratio between the diameter of the aerosol-generating article at the oral end and the diameter of the aerosol-generating article at the distal end (D ME / D DE Preferably, the ratio between the diameter of the aerosol-generating article at the mouth end and the diameter of the aerosol-generating article at the distal end (D ME / D DE ) is about 1.25 or less. Even more preferably, the ratio between the diameter of the aerosol-generating article at the oral end and the diameter of the aerosol-generating article at the distal end (D ME / D DE ) is about 1.20 or less. In particularly preferred embodiments, the ratio between the diameter of the aerosol-generating article at the oral end and the diameter of the aerosol-generating article at the distal end (D ME / D DE ) is less than or equal to 1.15 or 1.10.

[0231] In some preferred embodiments, the ratio between the diameter of the aerosol-generating article at the oral end and the diameter of the aerosol-generating article at the distal end (D ME / D DE ) is about 1.01 to 1.30, more preferably 1.02 to 1.30, and even more preferably 1.05 to 1.30.

[0232] In other embodiments, the ratio between the diameter of the aerosol-generating article at the oral end and the diameter of the aerosol-generating article at the distal end (D ME / D DE ) is about 1.01 to 1.25, more preferably 1.02 to 1.25, and even more preferably 1.05 to 1.25. In a further embodiment, the ratio between the diameter of the aerosol-generating article at the oral end and the diameter of the aerosol-generating article at the distal end (D ME / D DE) is about 1.01 to 1.20, more preferably 1.02 to 1.20, and even more preferably 1.05 to 1.20. In still further embodiments, the ratio between the diameter of the aerosol-generating article at the oral end and the diameter of the aerosol-generating article at the distal end (D ME / D DE ) is about 1.01 to 1.15, more preferably 1.02 to 1.15, and even more preferably 1.05 to 1.15.

[0233] By way of example, the outer diameter of the article may be substantially constant over a distal portion of the aerosol-generating article that extends at least about 5 millimeters or at least about 10 millimeters from the distal end. Alternatively, the outer diameter of the article may taper over a distal portion of the article that extends at least about 5 millimeters or at least about 10 millimeters from the distal end.

[0234] In certain preferred embodiments of the present invention, as described above, the elements of the aerosol-generating article are arranged so that the center of mass of the aerosol-generating article is at least about 60 percent along the length of the aerosol-generating article from the downstream end, more preferably the elements of the aerosol-generating article are arranged so that the center of mass of the aerosol-generating article is at least about 62 percent along the length of the aerosol-generating article from the downstream end, and more preferably at least about 65 percent along the length of the aerosol-generating article from the downstream end.

[0235] The center of mass is preferably no more than about 70 percent along the length of the aerosol-generating article from the downstream end.

[0236] Providing an arrangement of elements that provides a center of mass closer to the upstream end than the downstream end results in an aerosol-generating article with a weight imbalance, with the upstream end being heavier. This weight imbalance can advantageously provide tactile feedback to the consumer, allowing them to distinguish between the upstream and downstream ends and insert the correct end into the aerosol generating device. This can be particularly beneficial when the upstream elements are provided such that the upstream and downstream ends of the aerosol-generating article visually resemble each other.

[0237] In embodiments of aerosol-generating articles according to the invention, both the aerosol cooling element and the support element are present, and these are preferably wrapped together in a combined wrapper that surrounds the aerosol cooling element and the support element but does not surround anything further downstream, such as a mouthpiece element.

[0238] In these embodiments, the aerosol cooling element and support element are combined before being surrounded by the combined wrapper, and then further combined with the mouthpiece segment.

[0239] From a manufacturing standpoint, this is advantageous in that it allows shorter aerosol-generating articles to be constructed.

[0240] In general, it can be difficult to handle individual elements with lengths smaller than their diameters. For example, for a 7-millimeter diameter element, a length of about 7 millimeters represents a threshold that is desirable to remain constant. However, a 10-millimeter aerosol-cooling element can be combined with a pair of 7-millimeter support elements on each side (and potentially with other elements, such as aerosol-forming substrate rods) to provide a 24-millimeter hollow segment, which can then be cut into two intermediate 12-millimeter hollow sections.

[0241] In a particularly preferred embodiment, the other components of the aerosol-generating article are individually surrounded by their own wrappers. In other words, the upstream element, the aerosol-forming substrate rod, the support element, and the aerosol cooling element are all individually wrapped. The support element and the aerosol cooling element are combined to form an intermediate hollow section. This is achieved by wrapping the support element and the aerosol cooling element in a combined wrapper. The upstream element, the aerosol-forming substrate rod, and the intermediate hollow section are then combined together with an outer wrapper. They are then combined with a mouthpiece element having its own wrapper using tipping paper.

[0242] Preferably, at least one of the components of the aerosol-generating article is enclosed in a hydrophobic wrapper.

[0243] The term "hydrophobicity" refers to a surface that exhibits water-repellent properties. One useful way to determine this is to measure the water contact angle. The "water contact angle" is the angle traditionally measured through a liquid where the liquid / vapor interface meets a solid surface. It quantifies the wettability of a solid surface by a liquid via Young's equation. Hydrophobicity or water contact angle may be determined by utilizing the TAPPI T558 test method, and the results are expressed as interfacial contact angles, reported in degrees, which can range from approximately zero to approximately 180 degrees.

[0244] In preferred embodiments, the hydrophobic wrapper comprises a paper layer having a water contact angle of about 30 degrees or greater, preferably about 35 degrees or greater, or about 40 degrees or greater, or about 45 degrees or greater.

[0245] By way of example, the paper layer may comprise PVOH (polyvinyl alcohol) or silicone. The PVOH may be applied to the paper layer as a surface coating, or the paper layer may include a surface treatment that includes PVOH or silicone.

[0246] In a particularly preferred embodiment, the aerosol-generating article according to the invention comprises, in a linear series arrangement, an upstream element, a rod of aerosol-forming substrate located immediately downstream of the upstream element, a support element located immediately downstream of the rod of aerosol-forming substrate, an aerosol cooling element located immediately downstream of the support element, a mouthpiece element located immediately downstream of the aerosol cooling element, and an outer wrapper surrounding the upstream element, support element, aerosol cooling element, and mouthpiece element.

[0247] More particularly, the rod of the aerosol-forming substrate may abut against the upstream element. The support element may abut against the rod of the aerosol-forming substrate. The aerosol-cooling element may abut against the support element. The mouthpiece element may abut against the aerosol-cooling element.

[0248] The aerosol-generating article has a substantially cylindrical shape and an outer diameter of about 7.25 millimeters. The circumference of the aerosol-generating article is preferably between 20 millimeters and 23 millimeters, more preferably between 21 millimeters and 22 millimeters.

[0249] The upstream element has a length of about 5 mm, the rod of the aerosol-generating article has a length of about 12 mm, the support element has a length of about 8 mm, and the mouthpiece element has a length of about 12 mm, so that the total length of the aerosol-generating article is about 45 mm.

[0250] The upstream element is in the form of a plug of cellulose acetate encased in a stiff plug wrap.

[0251] The aerosol-generating article comprises an elongated susceptor longitudinally disposed substantially within the rod of the aerosol-forming substrate and in thermal contact with the aerosol-forming substrate, the susceptor being in the form of a strip or blade and having a length substantially equal to the length of the rod of the aerosol-forming substrate and a thickness of about 60 micrometers.

[0252] The support element is in the form of a hollow cellulose acetate tube and has an inner diameter of about 1.9 millimeters, so that the peripheral wall thickness of the support element is about 2.675 millimeters.

[0253] The aerosol cooling element is in the form of a finer hollow cellulose acetate tube and has an inner diameter of about 3.25 millimeters, so the peripheral wall thickness of the aerosol cooling element is about 2 millimeters.

[0254] The mouthpiece is in the form of a low density cellulose acetate filter segment.

[0255] The rod of aerosol-forming substrate comprises at least one of the types of aerosol-forming substrates mentioned above, such as homogenized tobacco, a gel formulation, or homogenized plant material containing particles of plants other than tobacco.

[0256] [Example] The following provides a non-exhaustive list of non-limiting examples, any one or more of the features of which may be combined with any one or more features of any other example, embodiment, or aspect described herein.

[0257] Example A: An aerosol-generating article, comprising: a rod of an aerosol-generating substrate; a ventilation zone located downstream of the rod of the aerosol-generating substrate, An aerosol-generating article, wherein the ventilation zone comprises perforations, one or more of the perforations having a non-circular cross-section with an ellipticity, the ellipticity being the ratio of the major diameter of the perforation divided by the minor diameter of the perforation, of at least 1.5, and wherein the thickness of the peripheral wall of the ventilation zone is between 0.1 millimeters and 2.5 millimeters. Example B: The aerosol-generating article of embodiment A, wherein one or more of the perforations have an elliptical cross-section. Example C: An aerosol-generating article according to any one of Examples A to B, wherein one or more of the perforations are in the form of a slit. Example D: An aerosol-generating article according to any one of Examples A to C, wherein for one or more of the perforations, the length of the perforation is greater than the width of the perforation. Example E: The aerosol-generating article of any one of Examples AD, wherein for one or more of the perforations, the longitudinal axis of the perforation is parallel to the longitudinal axis of the aerosol-generating article. Example F: An aerosol-generating article according to any one of Examples A to E, wherein the one or more perforations have a width of from 0.05 mm to 0.2 mm, preferably from 0.1 mm to 0.15 mm, and most preferably from 0.11 mm to 0.13 mm. Example G: An aerosol-generating article according to any one of Examples A to F, wherein the one or more perforations have a length of from 0.25 mm to 1.0 mm, preferably from 0.4 mm to 0.8 mm, and most preferably from 0.5 mm to 0.6 mm. Example H: An aerosol-generating article according to any one of Examples A to G, wherein the ellipticity of the perforations is at least 2, preferably at least 3, more preferably at least 4, and most preferably at least 5. Example I: An aerosol-generating article according to any one of Examples A to H, wherein 10 to 12 perforations are provided, preferably 11 perforations. Example J: An aerosol-generating article according to any one of Examples A to I, wherein each perforation has a central axis, the aerosol-generating article has a central axis, and the minimum distance between the central axis of each perforation and the central axis of the aerosol-generating article is 3% to 15% of the outer diameter of the aerosol-generating article, preferably 4% to 13% of the outer diameter of the aerosol-generating article, more preferably 5% to 10% of the outer diameter of the aerosol-generating article, and most preferably 6% of the outer diameter of the aerosol-generating article. Example K: An aerosol-generating article according to any one of Examples A to J, wherein each central axis of each perforation is angled at an angle of 3 to 20 degrees, preferably 4 to 15 degrees, more preferably 5 to 10 degrees, and most preferably 7 degrees, relative to the radial direction of the aerosol-generating article. Example L: An aerosol-generating article according to any one of Examples A to K, wherein the ventilation zone is configured as a hollow tubular ventilation zone, and the inner diameter of the hollow tubular ventilation zone is 2.5 mm to 5.0 mm, preferably 3.0 mm to 4.0 mm, more preferably 3.1 mm to 3.5 mm, and most preferably 3.3 mm. Example M: A ventilation zone is disposed within the second hollow tubular segment of the aerosol cooling element, the second hollow tubular segment having a length of 130 mm 3 ~200mm 3 , preferably 155mm 3 ~185mm 3 , more preferably 170 mm 3 The aerosol-generating article of any one of Examples A to L, having an internal volume of Example N: The aerosol-generating article of any of Examples A-M, wherein the perforations are disposed in the peripheral wall of the ventilation zone, and preferably the perforations have a non-constant pitch having a coefficient of variation of pitch greater than 5%. Example O: The aerosol-generating article of any one of Examples A to N, wherein the thickness of the peripheral wall of the ventilation zone is between 0.8 millimeters and 2.2 millimeters, more preferably between 1.2 millimeters and 1.8 millimeters, and most preferably about 1.5 millimeters. Example P: The aerosol-generating article of any one of Examples A to O, wherein the perforations are arranged in rows. Example Q: An aerosol-generating article according to any one of Examples A to P, wherein the distance between the perforations in the ventilation zone and the downstream end of the rod of the aerosol-generating substrate is 1 mm to 6 mm, preferably 2 mm to 5 mm, more preferably 3 mm to 4 mm. Example R: An aerosol-generating article according to any one of Examples A to Q, wherein the distance between the perforations in the ventilation zone and the downstream end of the aerosol-generating article is between 10 mm and 26 mm, preferably between 12 mm and 24 mm, more preferably between 14 mm and 22 mm, and most preferably between 16 mm and 20 mm. Example S: The aerosol-generating article of any of Examples A-R, wherein the perforations are configured to allow ambient air to be drawn into the ventilation zone. Example T: The aerosol-generating article of any one of Examples A to S, wherein the ratio of ambient air drawn into the ventilation zone through the perforations to air drawn into the ventilation zone through the rod of the aerosol-forming substrate is between 5 percent and 75 percent, preferably between 20 percent and 65 percent, more preferably between 30 percent and 60 percent, more preferably between 40 percent and 55 percent, and most preferably 50 percent. Example U: The aerosol-generating article of any one of Examples A to T, wherein the aerosol-generating article further comprises a filter plug downstream of the ventilation zone, the filter plug having a withdrawal resistance of between 5 mm HO and 80 mm HO, preferably between 10 mm HO and 65 mm HO, more preferably between 15 mm HO and 50 mm HO, more preferably between 20 mm HO and 40 mm HO, and most preferably between 30 mm HO. Example V: An aerosol generating system comprising an aerosol generating device having a cavity for receiving the aerosol-generating article of any one of Examples A to U. Example W: 1. A method for producing an aerosol-generating article, comprising: providing a rod of aerosol-generating substrate; providing a ventilation zone downstream of the rod of the aerosol-generating substrate; forming non-circular perforations in a peripheral wall of the ventilation zone having an ellipticity, where the ellipticity is the ratio of the major diameter of the perforation divided by the minor diameter of the perforation, and is at least 1.5, and the thickness of the peripheral wall of the ventilation zone is between 0.1 millimeters and 2.5 millimeters. Example X: The aerosol-generating article may comprise a rod of aerosol-forming substrate. The aerosol-generating article may further comprise a ventilation zone located downstream of the rod of aerosol-forming substrate. The ventilation zone may comprise 5 to 15 perforations, preferably 7 to 14 perforations, more preferably 9 to 13 perforations, more preferably 10 to 12 perforations, and most preferably 11 perforations. Example Y: The aerosol-generating article may include a rod of aerosol-generating substrate. The aerosol-generating article may further include a ventilation zone located downstream of the rod of aerosol-generating substrate. The ventilation zone may include perforations. The perforations may be located in a peripheral wall of the ventilation zone. The perforations may have a non-constant pitch with a coefficient of variation of pitch greater than 5%.

[0258] The invention will be further explained with reference to the drawings.

[0259] 1 comprises a rod 12 of aerosol-forming substrate 12 and a downstream section 14 located downstream of the rod 12 of aerosol-forming substrate. Additionally, the aerosol-generating article 10 comprises an upstream section 16 located upstream of the rod 12 of aerosol-forming substrate. Thus, the aerosol-generating article 10 may extend from an upstream or distal end 18 to a downstream or oral end 20.

[0260] The aerosol-generating article has a total length of about 45 millimeters.

[0261] The downstream section 14 comprises a support element 22 located immediately downstream of the rod 12 of the aerosol-forming substrate, the support element 22 being longitudinally aligned with the rod 12. In the embodiment of Figure 1, the upstream end of the support element 18 abuts the downstream end of the rod 12 of the aerosol-forming substrate. In addition, the downstream section 14 comprises an aerosol-cooling element 24 located immediately downstream of the support element 22, the aerosol-cooling element 24 being in longitudinal alignment with the rod 12 and the support element 22. In the embodiment of Figure 1, the upstream end of the aerosol-cooling element 24 abuts the downstream end of the support element 22.

[0262] As will become apparent from the description below, the support element 22 and the aerosol cooling element 24 together define an intermediate hollow section 50 of the aerosol-generating article 10. As a whole, the intermediate hollow section 50 does not contribute substantially to the overall RTD of the aerosol-generating article. The RTD of the intermediate hollow section 26 as a whole is substantially 0 millimeters HO.

[0263] The support element 22 may include a first hollow tubular segment 26. The first hollow tubular segment 26 is provided in the form of a hollow cylindrical tube made of cellulose acetate. The first hollow tubular segment 26 defines an interior cavity 28 extending entirely from the upstream end 30 of the first hollow tubular segment to the downstream end 32 of the first hollow tubular segment 20. The interior cavity 28 is substantially empty, thereby allowing substantially unrestricted airflow along the interior cavity 28. The first hollow tubular segment 26, and consequently the support element 22, does not substantially contribute to the overall RTD of the aerosol-generating article 10. More specifically, the RTD of the first hollow tubular segment 26 (which is substantially the RTD of the support element 22) is substantially 0 millimeters HO.

[0264] The first hollow tubular segment 26 has a length of about 8 millimeters, an outer diameter of about 7.25 millimeters, and an inner diameter (D FTS ) The peripheral wall thickness of the first hollow tubular segment 26 is therefore approximately 2.67 millimeters.

[0265] The aerosol cooling element 24 includes a second hollow tubular segment 34. The second hollow tubular segment 34 is provided in the form of a hollow cylindrical tube made of cellulose acetate. The second hollow tubular segment 34 defines an interior cavity 36 extending from an upstream end 38 of the second hollow tubular segment all the way to a downstream end 40 of the second hollow tubular segment 34. The interior cavity 36 is substantially empty, thereby allowing substantially unrestricted airflow along the interior cavity 36. The second hollow tubular segment 28, and consequently, the aerosol cooling element 24, does not substantially contribute to the overall RTD of the aerosol-generating article 10. More specifically, the RTD of the second hollow tubular segment 34 (which is essentially the RTD of the aerosol cooling element 24) is substantially 0 millimeters HO.

[0266] The second hollow tubular segment 34 has a length of about 8 millimeters, an outer diameter of about 7.25 millimeters, and an inner diameter (D STS ) of the first hollow tubular segment 26. The thickness of the peripheral wall of the second hollow tubular segment 34 is therefore about 2 millimeters. FTS ) and the inner diameter (D STS ) is about 0.75.

[0267] The aerosol-generating article 10 includes a ventilation zone 60 provided at a location along the second hollow tubular segment 34. More specifically, the ventilation zone is provided approximately 2 millimeters from the upstream end of the second hollow tubular segment 34. The ventilation level of the aerosol-generating article 10 is approximately 25 percent.

[0268] 1, downstream section 14 further comprises a mouthpiece element 42 located downstream of intermediate hollow section 50. More particularly, mouthpiece element 42 is positioned immediately downstream of aerosol cooling element 24. As shown in the drawing of FIG. 1, the upstream end of mouthpiece element 42 abuts downstream end 40 of aerosol cooling element 18.

[0269] Mouthpiece element 42 is provided in the form of a cylindrical plug of low density cellulose acetate.

[0270] Mouthpiece element 42 has a length of about 12 millimeters and an outer diameter of about 7.25 millimeters. The RTD of mouthpiece element 42 is about 12 millimeters H2O.

[0271] The rod 12 includes an aerosol-forming substrate of one of the types described above.

[0272] The rod 12 of aerosol-forming substrate has an outer diameter of about 7.25 millimeters and a length of about 12 millimeters.

[0273] The aerosol-generating article 10 further comprises an elongated susceptor 44 within the aerosol-forming substrate rod 12. More particularly, the susceptor 44 is substantially longitudinally disposed within the aerosol-forming substrate, such as generally parallel to the longitudinal axis of the rod 12. As shown in the drawing in Figure 1, the susceptor 44 is positioned at a radially central location within the rod and effectively extends along the longitudinal axis of the rod 12.

[0274] The susceptor 44 extends completely from the upstream end to the downstream end of the rod 12. In practice, the susceptor 44 has substantially the same length as the rod 12 of the aerosol-forming substrate.

[0275] In the embodiment of Figure 1, the susceptor 44 is provided in the form of a strip, having a length of approximately 12 millimeters, a thickness of approximately 60 micrometers, and a width of approximately 4 millimeters. The upstream section 16 includes an upstream element 46 located immediately upstream of the aerosol-forming substrate rod 12, and the upstream element 46 is longitudinally aligned with the rod 12. In the embodiment of Figure 1, the downstream end of the upstream element 46 abuts the upstream end of the aerosol-forming substrate rod 12. This advantageously prevents the susceptor 44 from becoming dislodged. Furthermore, this prevents consumers from accidentally touching the heated susceptor 44 after use.

[0276] The upstream element 46 is provided in the form of a cylindrical plug of cellulose acetate surrounded by a hard wrapper. The upstream element 46 has a length of approximately 5 millimeters. The RTD of the upstream element 46 is approximately 30 millimeters HO.

[0277] FIG. 2 illustrates perforations 62 in a ventilation zone 60. The ventilation zone 60 is provided at a location along the second hollow tubular segment 34. The perforations 62 are disposed within the peripheral wall of the hollow tubular segment 34. The perforations 62 are arranged in a row around the peripheral wall of the hollow tubular segment 34. The perforations 62 are configured to allow ambient air to flow into the interior cavity 36. FIG. 2 illustrates that eleven perforations are provided in the peripheral wall of the hollow tubular segment 34. This number of perforations 62 has been found to be particularly beneficial for aerosol generation.

[0278] 3 shows a non-circular perforation 62. The perforation 62 has an ellipticity with a length L substantially greater than the width W of the perforation 62. The length of the perforation 62 extends parallel to the central axis of the aerosol-generating article.

[0279] Features described with respect to one embodiment may equally apply to other embodiments of the invention.

Claims

1. An aerosol-generating article, comprising: a rod of an aerosol-generating substrate; a ventilation zone located downstream of the rod of the aerosol-generating substrate, 1. An aerosol-generating article wherein the ventilation zone comprises perforations, one or more of the perforations having a non-circular cross-section with an ellipticity, the ellipticity being the ratio of the major diameter of the perforation divided by the minor diameter of the perforation, of at least 1.5; the thickness of the peripheral wall of the ventilation zone is from 0.1 millimeters to 2.5 millimeters; and the one or more perforations have a width of from 0.05 millimeters to 0.2 millimeters, preferably from 0.1 millimeters to 0.15 millimeters, and most preferably from 0.11 millimeters to 0.13 millimeters; and the one or more perforations have a length of from 0.25 millimeters to 1.0 millimeters, preferably from 0.4 millimeters to 0.8 millimeters, and most preferably from 0.5 millimeters to 0.6 millimeters.

2. 2. The aerosol-generating article of claim 1, wherein one or more of the perforations has an elliptical cross-section.

3. 3. The aerosol-generating article according to claim 1, wherein one or more of the perforations are slit-shaped.

4. An aerosol-generating article as described in any one of claims 1 to 3, wherein for one or more of the perforations, the length of the perforation is greater than the width of the perforation, and preferably, for one or more of the perforations, the longitudinal axis of the perforation is parallel to the longitudinal axis of the aerosol-generating article.

5. 5. An aerosol-generating article according to any preceding claim, wherein the ellipticity of the perforations is at least 2, preferably at least 3, more preferably at least 4, and most preferably at least 5.

6. 6. The aerosol-generating article of any one of claims 1 to 5, wherein the ventilation zone is configured as a hollow tubular ventilation zone, the inner diameter of the hollow tubular ventilation zone being 2.5 millimeters to 5.0 millimeters, preferably 3.0 millimeters to 4.0 millimeters, more preferably 3.1 millimeters to 3.5 millimeters, and most preferably 3.3 millimeters.

7. The ventilation zone is disposed within a hollow tubular segment of the aerosol cooling element, the hollow tubular segment having a length of 130 mm 3 ~200mm 3 , preferably 155 mm 3 ~185mm 3 , more preferably 170 mm 3 7. The aerosol-generating article according to claim 1, having an internal volume of

8. 8. An aerosol-generating article according to any one of claims 1 to 7, wherein the distance between the perforations in the ventilation zone and the downstream end of the rod of the aerosol-generating substrate is from 1 millimetre to 6 millimetres, preferably from 2 millimetres to 5 millimetres, more preferably from 3 millimetres to 4 millimetres.

9. 9. An aerosol-generating article according to any one of claims 1 to 8, wherein the distance between the perforations in the ventilation zone and the downstream end of the aerosol-generating article is from 10 millimetres to 26 millimetres, preferably from 12 millimetres to 24 millimetres, more preferably from 14 millimetres to 22 millimetres, and most preferably from 16 millimetres to 20 millimetres.

10. 10. An aerosol-generating article according to any one of claims 1 to 9, wherein the perforations are configured to allow ambient air to be drawn into the ventilation zone, and preferably the ratio of ambient air drawn into the ventilation zone through the perforations to air drawn into the ventilation zone through the rod of the aerosol-forming substrate is from 5 to 75 percent, preferably from 20 to 65 percent, more preferably from 30 to 60 percent, more preferably from 40 to 55 percent, and most preferably 50 percent.

11. The aerosol-generating article further comprises a filter plug downstream of the ventilation zone, the filter plug having a pull-out resistance of 5 millimeters H 2 0 to 80mm H 2 0, preferably 10 mm H 2 O to 65mm H 2 0, more preferably 15 mm H 2 O to 50mm H 2 0, more preferably 20 mm H 2 O to 40mm H 2 0, most preferably 30 mm H 2 The aerosol-generating article according to any one of claims 1 to 10, wherein O is a hydroxybenzoate.

12. 12. An aerosol-generating article according to any preceding claim, wherein the aerosol-generating article further comprises a substrate wrapper at least partially surrounding the aerosol-forming substrate rod, the substrate wrapper having a thickness of 50 micrometers or more, preferably 65 micrometers or more, more preferably 80 micrometers or more.

13. An aerosol generating system comprising an aerosol generating device having a cavity for receiving an aerosol-generating article according to any one of claims 1 to 12.

14. 1. A method for producing an aerosol-generating article, comprising: - providing a rod of aerosol-generating substrate; - providing a ventilation zone downstream of the rod of the aerosol-generating substrate; forming non-circular perforations in a peripheral wall of the ventilation zone having an ellipticity, the ellipticity being the ratio of the major diameter of a perforation divided by the minor diameter of the perforation, of at least 1.5; the thickness of the peripheral wall of the ventilation zone being between 0.1 millimeters and 2.5 millimeters; one or more perforations having a width of between 0.05 millimeters and 0.2 millimeters, preferably between 0.1 millimeters and 0.15 millimeters, and most preferably between 0.11 millimeters and 0.13 millimeters; and one or more perforations having a length of between 0.25 millimeters and 1.0 millimeters, preferably between 0.4 millimeters and 0.8 millimeters, and most preferably between 0.5 millimeters and 0.6 millimeters.

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