RU2849419C1 - Aerosol-generating device with ventilation - Google Patents

Abstract

FIELD: tobacco industry.

SUBSTANCE: aerosol-generating product comprising an aerosol-generating substrate, a downstream section extending from a downstream end of the aerosol-generating substrate to a downstream end of the aerosol-generating product, wherein the downstream section contains a ventilation zone for providing ventilation to the downstream section. The ventilation zone extends from the downstream end to the upstream end, wherein the upstream end is located less than 5 millimetres from the downstream end of the aerosol-generating substrate. The drag resistance of the downstream section is less than 10 mm water column, and the ventilation zone contains a porous portion of the downstream section with at least 20 percent ventilation.

EFFECT: ensuring increased aerosol delivery.

14 cl, 4 dwg

Description

The present invention relates to an aerosol-generating article comprising an aerosol-generating substrate and adapted to produce an inhalable aerosol upon heating.

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, the aerosol is generated by heat transfer from a heat source to a physically separate aerosol-generating substrate or material, which may be positioned 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 air drawn through the aerosol-generating article. As the released compounds cool, they condense to form an aerosol.

A number of prior art documents disclose aerosol-generating devices for consuming aerosol-generating articles. Such devices include, for example, electrically heated aerosol-generating devices in which the aerosol is generated by transferring heat from one or more electrical heating elements of the aerosol-generating device to an aerosol-generating substrate of the heated aerosol-generating article. For example, electrically heated aerosol-generating devices have been proposed that comprise an internal heating plate that is adapted for insertion into an aerosol-generating substrate. Alternatively, WO 2015/176898 proposes inductively heated aerosol-generating articles comprising an aerosol-generating substrate and a susceptor located within the aerosol-generating substrate. A further alternative embodiment has been described in document WO 2020/115151, which discloses an aerosol generating article used in combination with an external heating system comprising one or more heating elements located around the periphery of the aerosol generating article.

Aerosol-generating products in which the tobacco-containing substrate is heated rather than combusted pose a number of challenges not previously encountered with conventional smoking products. First, tobacco-containing substrates are typically heated to significantly lower temperatures than those reached by the combustion front in a conventional cigarette. This can impact the release of nicotine from the tobacco-containing substrate and the delivery of nicotine to the consumer. At the same time, if the heating temperature is increased in an attempt to enhance nicotine delivery, the generated aerosol typically needs to be cooled to a greater extent and more quickly before reaching the consumer. However, technical solutions widely used to cool the mainstream smoke in conventional smoking products, such as the provision of a highly efficient filtration segment at the mouth end of the cigarette, can have undesirable effects on an aerosol-generating product in which the tobacco-containing substrate is heated rather than combusted, as they can reduce nicotine delivery.

To address one or more issues specifically related to heating, rather than burning, the aerosol-generating substrate to generate the aerosol, a number of aerosol-generating articles have been proposed in which multiple elements are combined, for example, in a longitudinal alignment, with an aerosol-generating element containing the aerosol-generating substrate. For example, the aerosol-generating element has been combined with a support element to provide improved structural strength to the article, an aerosol-cooling element adapted to reduce the aerosol temperature, a low-filtration mouthpiece element, and so on.

There is a general need for aerosol-generating products that are easy to use, offer improved usability, and are more environmentally friendly. It would also be desirable to provide aerosol-generating products that are easier to manufacture and that can make the entire production chain more sustainable and cost-effective. There is also a need for an aerosol-generating product that is particularly suitable for use in combination with an external heating system, particularly one that features improved aerosol generation and aerosol-forming agent delivery.

It would therefore be desirable to provide a new and improved aerosol-generating article adapted to meet at least one of the needs described above. Furthermore, it would be desirable to provide one such aerosol-generating article that can be manufactured efficiently and at high speed, preferably with a satisfactorily low RTD variability from one article to another.

Aerosol-generating devices may contain ventilation for aerosol dilution and cooling. In this case, it may be desirable to effectively mix the dilution air with the aerosol before delivery.

The present invention relates to an aerosol-generating article. The aerosol-generating article may be suitable for producing an inhalable aerosol upon heating. The aerosol-generating article may comprise an aerosol-generating element. The aerosol-generating element may be in the form of a rod. The aerosol-generating element may comprise an aerosol-generating substrate, wherein the aerosol-generating substrate comprises a substance for forming an aerosol. The aerosol-generating article may comprise an aerosol-generating substrate. The aerosol-generating article may comprise a downstream section extending from the downstream end of the aerosol-generating substrate to the downstream end of the aerosol-generating article. The downstream section may comprise a first ventilation zone for providing ventilation into the downstream section. The first ventilation zone may extend from the downstream end to the upstream end. The upstream end of the first ventilation zone may be less than 5 millimeters from the downstream end of the aerosol-generating substrate. The draw resistance of the downstream section may be less than 10 mm H2O.

According to the present invention, an aerosol-generating article is provided, wherein the aerosol-generating article comprises: an aerosol-generating substrate; a downstream section extending from the downstream end of the aerosol-generating substrate to the downstream end of the aerosol-generating article. The downstream section comprises a first ventilation zone for providing ventilation into the downstream section. The first ventilation zone extends from the downstream end to the upstream end. The upstream end of the first ventilation zone is at a distance of less than 5 millimetres from the downstream end of the aerosol-generating substrate. The draw resistance of the downstream section is less than 10 mm H2O.

Providing a downstream section with such a low RTD allows the aerosol generated in the aerosol-generating substrate to pass relatively unimpeded to the downstream end of the downstream section. This can advantageously maximize aerosol delivery. Prior art products with higher RTD downstream sections typically include high-denier filter sections in the downstream section, which remove flavor components from the aerosol. Providing a low RTD downstream section can advantageously prevent this phenomenon.

Furthermore, providing a first ventilation zone can cause a temperature drop by introducing cooler outside air into the downstream section. This can have a beneficial effect on aerosol particle nucleation and growth, which in turn can improve aerosol delivery.

Providing the first ventilation zone near the downstream end of the aerosol-generating substrate places the first ventilation zone as far from the downstream end of the aerosol-generating article as possible. This may advantageously ensure that the cooler outside air has the maximum amount of space in which it can mix with the main aerosol flow before both exit the downstream end of the aerosol-generating article. This may allow for the most complete mixing of the main aerosol flow and the cooler outside air. It should be understood that the first ventilation zone may be provided such that secondary aerosol can be admitted into the downstream section. In this case, providing the first ventilation zone near the downstream end of the aerosol-generating substrate may advantageously allow for the most complete mixing of the main aerosol flow and the secondary aerosol.

Additionally, providing a downstream section having a low RTD, such as when the downstream section is a hollow tubular element, may advantageously allow the primary aerosol stream to readily mix with either cooler outside air or secondary aerosol entering through the first ventilation zone.

Accordingly, the combination of a first ventilation zone located near the aerosol-generating substrate and a downstream section with a low RTD can synergistically promote efficient mixing of the main aerosol flow with either cooler ambient air or secondary aerosol entering through the first ventilation zone. This, in turn, can advantageously ensure a more uniform and consistent aerosol for delivery.

According to the present invention, an aerosol-generating article is provided, wherein the aerosol-generating article comprises: an aerosol-generating substrate; a downstream section extending from the downstream end of the aerosol-generating substrate to the downstream end of the aerosol-generating article. The downstream section comprises a first ventilation zone for providing ventilation into the downstream section. The first ventilation zone extends from the downstream end to the upstream end. The upstream end of the first ventilation zone is located at a distance of less than 5 millimeters from the downstream end of the aerosol-generating substrate. The first ventilation zone comprises a porous portion of the downstream section with a ventilation of at least 20 percent.

Providing a porous portion to allow ventilation into a downstream section may advantageously improve mixing of the main aerosol stream with either cooler outside air or secondary aerosol entering through the first ventilation zone. Without being limited by theory, this may be due to the fact that cooler outside air or secondary aerosol enters the downstream section through a large number of small pores, rather than a smaller number of larger perforations in cases where ventilation is provided by a perforation line. A large number of small pores may result in more uniform mixing of the main aerosol stream with either cooler outside air or secondary aerosol entering through the first ventilation zone.

Additionally, as described above, providing the first ventilation zone near the downstream end of the aerosol-generating substrate places the first ventilation zone as far away from the downstream end of the aerosol-generating article as possible. This can advantageously ensure that cooler outside air has the maximum amount of space in which to mix with the main aerosol flow before both exit the downstream end of the aerosol-generating article.

The present invention provides an aerosol-generating article for generating an inhalable aerosol upon heating. The aerosol-generating article comprises a member containing an aerosol-generating substrate.

The term "aerosol-generating article" is used in this document to refer to an article in which an aerosol-generating substrate is heated to produce and deliver an inhalable aerosol to the user. For the purposes of this document, the term "aerosol-generating substrate" refers to a substrate configured to release volatile compounds upon heating to generate an aerosol.

A conventional cigarette is ignited when the user applies a flame to one end of the cigarette and draws air through the other end. The localized heat provided by the flame and oxygen in the air drawn through the cigarette ignites the end of the cigarette, and the resulting combustion generates inhaled smoke. In contrast, in heated aerosol-generating articles, the aerosol is generated by heating a flavor-generating substrate, such as tobacco. Known heated aerosol-generating articles include, for example, electrically heated aerosol-generating articles and aerosol-generating articles in which the aerosol is generated by heat transfer from a combustible heat-generating element or heat source to a physically separate aerosol-forming material. For example, the aerosol-generating articles according to the present invention find particular application in aerosol-generating systems comprising an electrically heated aerosol-generating device having an internal heating plate adapted for insertion into the rod of an aerosol-generating substrate. Aerosol-generating articles of this type are described in the prior art, for example, in document EP 0 822 760.

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

The aerosol-generating element may be in the form of a rod made of or containing an aerosol-generating substrate. As used herein, the term "rod" is used to describe a substantially cylindrical element with a substantially circular, oval, or elliptical cross-section.

For the purposes of this document, the term "longitudinal" refers to the direction corresponding to the major longitudinal axis of the aerosol-generating article, which extends between the upstream and downstream ends of the aerosol-generating article. For the purposes of this document, the terms "upstream" and "downstream" describe the relative positions of elements or portions of elements of the aerosol-generating article relative to the direction in which the aerosol is transported through the aerosol-generating article during use.

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

The term "length" refers to the longitudinal dimension of an aerosol-generating component. For example, it can be used to describe the longitudinal dimension of a rod or elongated tubular elements.

The aerosol-generating article further comprises a downstream section located at a location downstream of the aerosol-generating substrate. As will be apparent from the following description of various embodiments of the aerosol-generating article according to the present invention, the downstream section may comprise one or more downstream elements.

In some embodiments, the downstream section may comprise a hollow section between the mouthpiece end of the aerosol-generating article and the aerosol-generating element. The hollow section may comprise a hollow tubular element.

In the context of this document, the term "hollow tubular element" is used to designate a substantially elongated element that defines a lumen or passage for air flow along its longitudinal axis. In particular, the term "tubular" will be used hereinafter to refer to a tubular element having a substantially cylindrical cross-section and defining at least one air flow channel that establishes continuous fluid communication between an upstream end of the tubular element and a downstream end of the tubular element. However, it should be understood that alternative geometries (e.g., alternative cross-sectional shapes) of the tubular element may be possible.

In the context of the present invention, the hollow tubular element provides a channel for unimpeded flow. This means that the hollow tubular element provides a negligible resistance to draw (RTD). The term "negligible RTD" is used to describe an RTD of less than 1 mm H2O per 10 millimeters of the length of the hollow tubular element, preferably less than 0.4 mm H2O per 10 millimeters of the length of the hollow tubular element, and more preferably less than 0.1 mm H2O per 10 millimeters of the length of the hollow tubular element.

Therefore, the flow channel must be free of any components that would impede longitudinal airflow. Preferably, the flow channel is substantially empty.

An aerosol-generating article may comprise a first ventilation zone located along a downstream section. More specifically, the aerosol-generating article may comprise a first ventilation zone located along a hollow tubular element. Fluid communication is thus established between the flow channel formed internally by the hollow tubular element and the external environment.

The aerosol-generating article may further comprise an upstream section at a location upstream of the aerosol-generating substrate rod. 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 aerosol-generating element.

As briefly described above, the aerosol generating article according to the present invention comprises an aerosol generating substrate.

In some embodiments, the aerosol-generating element may be provided in the form of a rod containing an aerosol-generating substrate. For example, the aerosol-generating element may comprise a rod of aerosol-generating substrate surrounded by a wrapper.

The aerosol-generating substrate may have a length of at least about 5 millimeters. Preferably, the aerosol-generating substrate has a length of at least about 7 millimeters. More preferably, the aerosol-generating substrate has a length of at least about 10 millimeters. In particularly preferred embodiments, the aerosol-generating substrate has a length of at least about 12 millimeters.

The aerosol-generating substrate can have a length of up to approximately 80 millimeters. Preferably, the aerosol-generating substrate has a length less than or equal to approximately 65 millimeters. More preferably, the aerosol-generating substrate has a length less than or equal to approximately 60 millimeters. Even more preferably, the aerosol-generating substrate has a length less than or equal to approximately 55 millimeters.

In particularly preferred embodiments, the aerosol-generating substrate has a length that is less than or equal to about 50 millimeters, more preferably less than or equal to about 35 millimeters, and even more preferably less than or equal to about 25 millimeters. In particularly preferred embodiments, the aerosol-generating substrate has a length that is less than or equal to about 20 millimeters or even less than or equal to about 15 millimeters.

In some embodiments, the aerosol-generating substrate has a length of from about 5 millimeters to about 60 millimeters, preferably from about 6 millimeters to about 60 millimeters, more preferably from about 7 millimeters to about 60 millimeters, even more preferably from about 10 millimeters to about 60 millimeters, most preferably from about 12 millimeters to about 60 millimeters. In other embodiments, the aerosol-generating substrate has a length of from about 5 millimeters to about 55 millimeters, preferably from about 6 millimeters to about 55 millimeters, more preferably from about 7 millimeters to about 55 millimeters, even more preferably from about 10 millimeters to about 55 millimeters, most preferably from about 12 millimeters to about 55 millimeters. In further embodiments, the aerosol-generating substrate has a length of from about 5 millimeters to about 50 millimeters, preferably from about 6 millimeters to about 50 millimeters, more preferably from about 7 millimeters to about 50 millimeters, even more preferably from about 10 millimeters to about 50 millimeters, most preferably from about 12 millimeters to about 50 millimeters.

In some particularly preferred embodiments, the aerosol-generating substrate has a length of from about 5 millimeters to about 30 millimeters, preferably from about 6 millimeters to about 30 millimeters, more preferably from about 7 millimeters to about 30 millimeters, even more preferably from about 10 millimeters to about 30 millimeters. In other particularly preferred embodiments, the aerosol-generating substrate has a length of from about 5 millimeters to about 20 millimeters, preferably from about 6 millimeters to about 20 millimeters, more preferably from about 7 millimeters to about 20 millimeters, even more preferably from about 10 millimeters to about 20 millimeters. In further particularly preferred embodiments, the aerosol-generating substrate has a length of from about 5 millimeters to about 15 millimeters, preferably from about 7 millimeters to about 20 millimeters, more preferably from about 9 millimeters to about 16 millimeters, even more preferably from about 10 millimeters to about 15 millimeters.

The aerosol generating substrate preferably has an outer diameter that is approximately equal to the outer diameter of the aerosol generating article.

Preferably, the aerosol-generating substrate has an outer diameter of at least about 3 millimeters, at least about 4 millimeters, or at least about 5 millimeters. More preferably, the aerosol-generating substrate has an outer diameter of at least about 6 millimeters. Even more preferably, the aerosol-generating substrate has an outer diameter of at least about 7 millimeters.

The aerosol-generating substrate preferably has an outer diameter of less than or equal to approximately 12 millimeters. More preferably, the aerosol-generating substrate has an outer diameter of less than or equal to approximately 10 millimeters. Even more preferably, the aerosol-generating substrate has an outer diameter of less than or equal to approximately 8 millimeters.

In general, it has been observed that the smaller the diameter of the aerosol-generating substrate, the lower the temperature required to raise the internal temperature of the aerosol-generating element so that sufficient quantities of volatile compounds are released from the aerosol-generating substrate to form the desired amount of aerosol. At the same time, without being limited by theory, it is understood that a smaller aerosol-generating substrate diameter allows for more rapid penetration of heat supplied to the aerosol-generating article into the entire volume of the aerosol-generating substrate. However, when the diameter of the aerosol-generating substrate is too small, the volume-to-surface ratio of the aerosol-generating substrate becomes less favorable, as the amount of available aerosol-generating substrate decreases.

An aerosol-generating substrate diameter within the ranges described herein is particularly advantageous in terms of balancing energy consumption and aerosol delivery. This advantage is particularly noticeable when an aerosol-generating article containing an aerosol-generating substrate having a diameter as described herein is used in combination with an external heater located around the periphery of the aerosol-generating article. It has been observed that under such operating conditions, less thermal energy is required to achieve a sufficiently high temperature in the core of the aerosol-generating substrate and in the core of the article as a whole. Thus, when operating at low temperatures, the desired target temperature in the core of the aerosol-generating substrate can be achieved within a desirably reduced timeframe and with lower energy consumption.

In some embodiments, the aerosol-generating substrate has an outer diameter of about 5 millimeters to about 12 millimeters, preferably about 6 millimeters to about 12 millimeters, more preferably about 7 millimeters to about 12 millimeters. In other embodiments, the aerosol-generating substrate has an outer diameter of about 5 millimeters to about 12 millimeters, preferably about 6 millimeters to about 10 millimeters, more preferably about 7 millimeters to about 10 millimeters. In further embodiments, the aerosol-generating substrate has an outer diameter of about 5 millimeters to about 8 millimeters, preferably about 6 millimeters to about 8 millimeters, more preferably about 7 millimeters to about 8 millimeters.

The aerosol generating substrate can have an outer diameter of 3.7 millimeters to 9 millimeters or 5.7 millimeters to 7.9 millimeters.

In particularly preferred embodiments, the aerosol-generating substrate has an outer diameter of less than approximately 7.5 millimeters. As an example, the aerosol-generating substrate may have an outer diameter of approximately 7.2 millimeters.

The length-to-diameter ratio of the aerosol generating element may be at least about 0.5. Preferably, the length-to-diameter ratio of the aerosol generating element is at least about 0.75. More preferably, the length-to-diameter ratio of the aerosol generating element is at least about 1.0. Even more preferably, the length-to-diameter ratio of the aerosol generating element is at least about 1.25.

The length-to-diameter ratio of the aerosol generating element may be less than or equal to approximately 3.0. Preferably, the length-to-diameter ratio of the aerosol generating element is less than or equal to approximately 2.75. More preferably, the length-to-diameter ratio of the aerosol generating element is less than or equal to approximately 2.5. Even more preferably, the length-to-diameter ratio of the aerosol generating element is less than or equal to approximately 2.25.

In some embodiments, the length-to-diameter ratio of the aerosol-generating element may be from about 0.5 to about 3.0. Preferably, the length-to-diameter ratio of the aerosol-generating element is from about 0.75 to about 3.0. More preferably, the length-to-diameter ratio of the aerosol-generating element is from about 1.0 to about 3.0. Even more preferably, the length-to-diameter ratio of the aerosol-generating element is from about 1.25 to about 3.0.

In other embodiments, the length-to-diameter ratio of the aerosol generating element may be from about 0.5 to about 2.75. Preferably, the length-to-diameter ratio of the aerosol generating element is from about 0.75 to about 2.75. More preferably, the length-to-diameter ratio of the aerosol generating element is from about 1.0 to about 2.75. Even more preferably, the length-to-diameter ratio of the aerosol generating element is from about 1.25 to about 2.75.

In further embodiments, the length-to-diameter ratio of the aerosol-generating element may be from about 0.5 to about 2.5. Preferably, the length-to-diameter ratio of the aerosol-generating element is from about 0.75 to about 2.5. More preferably, the length-to-diameter ratio of the aerosol-generating element is from about 1.0 to about 2.5. Even more preferably, the length-to-diameter ratio of the aerosol-generating element is from about 1.25 to about 2.5.

In still further embodiments, the length-to-diameter ratio of the aerosol generating element may be from about 0.5 to about 2.25. Preferably, the length-to-diameter ratio of the aerosol generating element is from about 0.75 to about 2.25. More preferably, the length-to-diameter ratio of the aerosol generating element is from about 1.0 to about 2.25. Even more preferably, the length-to-diameter ratio of the aerosol generating element is from about 1.25 to about 2.25.

In particularly preferred embodiments, the length to diameter ratio of the aerosol generating element may be at least about 1.3, more preferably about 1.4, even more preferably about 1.5.

In particularly preferred embodiments, the length to diameter ratio of the aerosol generating element may be less than or equal to about 2.0, more preferably less than or equal to about 1.9, even more preferably less than or equal to about 1.8.

In some embodiments, the length to diameter ratio of the aerosol generating element is preferably from about 1.3 to about 2.0, more preferably from about 1.4 to about 2.0, even more preferably from about 1.5 to about 2.0. In other embodiments, the length to diameter ratio of the aerosol generating element is preferably from about 1.3 to about 1.9, more preferably from about 1.4 to about 1.7, even more preferably from about 1.5 to about 1.9. In further embodiments, the length to diameter ratio of the aerosol generating element is preferably from about 1.3 to about 1.8, more preferably from about 1.4 to about 1.8, even more preferably from about 1.5 to about 1.8.

The ratio between the length of the aerosol-generating element and the overall length of the aerosol-generating article may be at least approximately 0.10. Preferably, the ratio between the length of the aerosol-generating element and the overall length of the aerosol-generating article is at least approximately 0.15. More preferably, the ratio between the length of the aerosol-generating element and the overall length of the aerosol-generating article is at least approximately 0.20. Even more preferably, the ratio between the length of the aerosol-generating element and the overall length of the aerosol-generating article is at least approximately 0.25.

In general, the ratio between the length of the aerosol-generating element and the overall length of the aerosol-generating article may be less than or equal to about 0.60. Preferably, the ratio between the length of the aerosol-generating element and the overall length of the aerosol-generating article is less than or equal to about 0.50. More preferably, the ratio between the length of the aerosol-generating element and the overall length of the aerosol-generating article is less than or equal to about 0.45. Even more preferably, the ratio between the length of the aerosol-generating element and the overall length of the aerosol-generating article is less than or equal to about 0.40. In particularly preferred embodiments, the ratio between the length of the aerosol-generating element and the overall length of the aerosol-generating article is less than or equal to about 0.35 and most preferably less than or equal to about 0.30.

In some embodiments, the ratio between the length of the aerosol-generating element and the overall length of the aerosol-generating article is from about 0.10 to about 0.45, preferably from about 0.15 to about 0.45, more preferably from about 0.20 to about 0.45, even more preferably from about 0.25 to about 0.45. In other embodiments, the ratio between the length of the aerosol-generating element and the overall length of the aerosol-generating article is from about 0.10 to about 0.40, preferably from about 0.15 to about 0.40, more preferably from about 0.20 to about 0.40, even more preferably from about 0.25 to about 0.40. In further embodiments, the ratio between the length of the aerosol-generating element and the total length of the aerosol-generating article is from about 0.10 to about 0.35, preferably from about 0.15 to about 0.35, more preferably from about 0.20 to about 0.35, even more preferably from about 0.25 to about 0.35. In yet further embodiments, the ratio between the length of the aerosol-generating element and the total length of the aerosol-generating article is from about 0.10 to about 0.30, preferably from about 0.15 to about 0.30, more preferably from about 0.20 to about 0.30, even more preferably from about 0.25 to about 0.30.

Preferably, the aerosol-generating element comprises a rod of aerosol-generating substrate having a substantially uniform cross-section along the rod's length. Particularly preferably, the rod of aerosol-generating substrate has a substantially circular cross-section.

As will be described in more detail below, the aerosol-generating article according to the present invention comprises a downstream section comprising a hollow tubular element. In the aerosol-generating article according to the present invention, the ratio between the length of the aerosol-generating element and the length of the hollow tubular element may be less than or equal to approximately 0.66. Preferably, the ratio between the length of the aerosol-generating element and the length of the hollow tubular element may be less than or equal to approximately 0.60. More preferably, the ratio between the length of the aerosol-generating element and the length of the hollow tubular element may be less than or equal to approximately 0.50. Even more preferably, the ratio between the length of the aerosol-generating element and the length of the hollow tubular element may be less than or equal to approximately 0.40.

In the aerosol-generating article according to the present invention, the ratio between the length of the aerosol-generating element and the length of the hollow tubular element may be at least about 0.10. Preferably, the ratio between the length of the aerosol-generating element and the length of the hollow tubular element may be at least about 0.15. More preferably, the ratio between the length of the aerosol-generating element and the length of the hollow tubular element may be at least about 0.20. Even more preferably, the ratio between the length of the aerosol-generating element and the length of the hollow tubular element may be at least about 0.25. In particularly preferred embodiments, the ratio between the length of the aerosol-generating element and the length of the hollow tubular element may be at least about 0.30.

In some embodiments, the ratio between the length of the aerosol generating element and the length of the hollow tubular element is from about 0.15 to about 0.60, preferably from about 0.20 to about 0.60, more preferably from about 0.25 to about 0.60, even more preferably from about 0.30 to about 0.60. In other embodiments, the ratio between the length of the aerosol generating element and the length of the hollow tubular element is from about 0.15 to about 0.50, preferably from about 0.20 to about 0.50, more preferably from about 0.25 to about 0.50, even more preferably from about 0.30 to about 0.50. In further embodiments, the ratio between the length of the aerosol generating element and the length of the hollow tubular element is from about 0.15 to about 0.40, preferably from about 0.20 to about 0.40, more preferably from about 0.25 to about 0.40, even more preferably from about 0.30 to about 0.40. As an example, the ratio between the length of the aerosol generating element and the length of the hollow tubular element can be about 0.35.

The density of the aerosol-generating substrate can be at least about 100 micrograms/cubic centimeter. Preferably, the density of the aerosol-generating substrate is at least about 115 micrograms/cubic centimeter. More preferably, the density of the aerosol-generating substrate is at least about 130 micrograms/cubic centimeter. Even more preferably, the density of the aerosol-generating substrate is at least about 140 micrograms/cubic centimeter.

The density of the aerosol-generating substrate may be less than or equal to about 200 micrograms/cubic centimeter. Preferably, the density of the aerosol-generating substrate is less than or equal to about 185 micrograms/cubic centimeter. More preferably, the density of the aerosol-generating substrate is less than or equal to about 170 micrograms/cubic centimeter. Even more preferably, the density of the aerosol-generating substrate is less than or equal to about 160 micrograms/cubic centimeter.

In some embodiments, the density of the aerosol-generating substrate is from 100 micrograms/cubic centimeter to 200 micrograms/cubic centimeter, preferably from 100 micrograms/cubic centimeter to 185 micrograms/cubic centimeter, more preferably from 100 micrograms/cubic centimeter to 170 micrograms/cubic centimeter, even more preferably from 100 micrograms/cubic centimeter to 160 micrograms/cubic centimeter. In other embodiments, the density of the aerosol-generating substrate is from 115 micrograms/cubic centimeter to 200 micrograms/cubic centimeter, preferably from 115 micrograms/cubic centimeter to 185 micrograms/cubic centimeter, more preferably from 115 micrograms/cubic centimeter to 170 micrograms/cubic centimeter, even more preferably from 115 micrograms/cubic centimeter to 160 micrograms/cubic centimeter. In further embodiments, the density of the aerosol-generating substrate is from 130 micrograms/cubic centimeter to 200 micrograms/cubic centimeter, preferably from 130 micrograms/cubic centimeter to 185 micrograms/cubic centimeter, more preferably from 130 micrograms/cubic centimeter to 170 micrograms/cubic centimeter, even more preferably from 130 micrograms/cubic centimeter to 160 micrograms/cubic centimeter. In still other embodiments, the density of the aerosol-generating substrate is from 140 micrograms/cubic centimeter to 200 micrograms/cubic centimeter, preferably from 140 micrograms/cubic centimeter to 185 micrograms/cubic centimeter, more preferably from 140 micrograms/cubic centimeter to 170 micrograms/cubic centimeter, even more preferably from 140 micrograms/cubic centimeter to 160 micrograms/cubic centimeter. In some particularly preferred embodiments, the density of the aerosol generating substrate is approximately 150 micrograms/cubic centimeter.

The density of the aerosol-generating substrate can be at least about 100 milligrams/cubic centimeter. Preferably, the density of the aerosol-generating substrate is at least about 115 milligrams/cubic centimeter. More preferably, the density of the aerosol-generating substrate is at least about 130 milligrams/cubic centimeter. Even more preferably, the density of the aerosol-generating substrate is at least about 140 milligrams/cubic centimeter.

The density of the aerosol-generating substrate may be less than or equal to approximately 200 milligrams/cubic centimeter. Preferably, the density of the aerosol-generating substrate is less than or equal to approximately 185 milligrams/cubic centimeter. More preferably, the density of the aerosol-generating substrate is less than or equal to approximately 170 milligrams/cubic centimeter. Even more preferably, the density of the aerosol-generating substrate is less than or equal to approximately 160 milligrams/cubic centimeter.

In some embodiments, the density of the aerosol-generating substrate is from 100 milligrams/cubic centimeter to 200 milligrams/cubic centimeter, preferably from 100 milligrams/cubic centimeter to 185 milligrams/cubic centimeter, more preferably from 100 milligrams/cubic centimeter to 170 milligrams/cubic centimeter, even more preferably from 100 milligrams/cubic centimeter to 160 milligrams/cubic centimeter. In other embodiments, the density of the aerosol-generating substrate is from 115 milligrams/cubic centimeter to 200 milligrams/cubic centimeter, preferably from 115 milligrams/cubic centimeter to 185 milligrams/cubic centimeter, more preferably from 115 milligrams/cubic centimeter to 170 milligrams/cubic centimeter, even more preferably from 115 milligrams/cubic centimeter to 160 milligrams/cubic centimeter. In further embodiments, the density of the aerosol-generating substrate is from 130 milligrams/cubic centimeter to 200 milligrams/cubic centimeter, preferably from 130 milligrams/cubic centimeter to 185 milligrams/cubic centimeter, more preferably from 130 milligrams/cubic centimeter to 170 milligrams/cubic centimeter, even more preferably from 130 milligrams/cubic centimeter to 160 milligrams/cubic centimeter. In still other embodiments, the density of the aerosol-generating substrate is from 140 milligrams/cubic centimeter to 200 milligrams/cubic centimeter, preferably from 140 milligrams/cubic centimeter to 185 milligrams/cubic centimeter, more preferably from 140 milligrams/cubic centimeter to 170 milligrams/cubic centimeter, even more preferably from 140 milligrams/cubic centimeter to 160 milligrams/cubic centimeter. In some particularly preferred embodiments, the density of the aerosol-generating substrate is about 150 milligrams/cubic centimeter.

As an example, the aerosol-generating element may comprise from about 100 milligrams to about 250 milligrams of an aerosol-generating substrate. In some embodiments, the aerosol-generating element comprises from about 210 milligrams to about 230 milligrams of an aerosol-generating substrate, preferably from 215 milligrams to about 220 milligrams of an aerosol-generating substrate. In other embodiments, the aerosol-generating element comprises from about 150 milligrams to about 180 milligrams of an aerosol-generating substrate, preferably from 160 milligrams to about 165 milligrams of an aerosol-generating substrate.

The aerosol generating substrate may be a solid aerosol generating substrate.

In certain preferred embodiments, the aerosol generating substrate comprises homogenized plant material, preferably homogenized tobacco material.

As used herein, the term "homogenized plant material" encompasses any plant material formed by agglomerating plant particles. For example, sheets or webs of homogenized tobacco material for aerosol-generating substrates according to the present invention may be formed by agglomerating tobacco material particles obtained by grinding, milling, or crushing plant material and, optionally, one or more of tobacco leaf lamellas and tobacco leaf veins. The homogenized plant material may be produced by casting, extrusion, papermaking, or any other suitable methods known in the art.

The homogenized plant material may be provided in any suitable form.

In some embodiments, the homogenized plant material may be in the form of one or more sheets. As used herein, the term "sheet" refers to a layered element having a width and length that are substantially greater than its thickness.

The homogenized plant material may be in the form of multiple beads or granules.

Homogenized plant material may be in the form of multiple strands, strips, or pieces. For the purposes of this document, the term "strand" describes an elongated element of material whose length significantly exceeds its width and thickness. The term "strand" should be understood to encompass strips, pieces, and any other homogenized plant material of similar shape. Strands of homogenized plant material may be formed from a sheet of homogenized plant material, for example, by cutting or dividing it into pieces, or by other methods, such as extrusion.

In some embodiments, the filaments may be formed in situ within the aerosol-generating substrate by separating or splitting a sheet of homogenized plant material during the formation of the aerosol-generating substrate, for example, by corrugating. The filaments of homogenized plant material within the aerosol-generating substrate may be separated from one another. Alternatively, each filament of homogenized plant material within the aerosol-generating substrate may be at least partially connected to an adjacent filament or filaments along the length of the filaments. For example, adjacent filaments may be connected via one or more fibers. This may occur, for example, if the filaments were formed by separating a sheet of homogenized plant material during the production of the aerosol-generating substrate, as described above.

If the aerosol-generating substrate contains homogenized plant material, the homogenized plant material may typically be provided in the form of one or more sheets. In particular, sheets of homogenized plant material can be produced by a casting process. Preferably, sheets of homogenized plant material can be produced by a papermaking process.

In some preferred embodiments, the aerosol-generating substrate comprises a chopped filler. In the context of this technical description, the term "chopped filler" is used to describe a mixture of ground plant material, such as tobacco plant material, including, in particular, one or more of leaf blades, processed stems and veins, and homogenized plant material.

Cut filler may also contain other trimmings, filler tobacco, or casing.

Preferably, the chopped filler comprises at least 25 percent of plant leaf blades, more preferably at least 50 percent of plant leaf blades, even more preferably at least 75 percent of plant leaf blades, and most preferably at least 90 percent of plant leaf blades. Preferably, the plant material is one of tobacco, mint, tea, and cloves. However, as will be described in more detail below, the present invention is equally applicable to other plant material that has the ability to release substances upon the application of heat, which can subsequently form an aerosol.

Preferably, the cut filler comprises tobacco plant material comprising leaf blades of one or more of light tobacco, dark tobacco, aromatic tobacco, and filler tobacco. In the context of the present invention, the term "tobacco" describes any plant belonging to the genus Nicotiana.

Light tobacco varieties are tobacco varieties with typically large, light-colored leaves. Throughout technical descriptions, the term "light tobacco" is used for flue-cured tobacco varieties. Examples of light tobacco varieties include Chinese flue-cured tobacco, Brazilian flue-cured tobacco, American flue-cured tobacco such as Virginia tobacco, Indian flue-cured tobacco, Tanzanian flue-cured tobacco, and other African flue-cured tobaccos. Light tobacco is characterized by a high sugar-to-nitrogen ratio. From an organoleptic perspective, light tobacco is a type of tobacco that, after curing, is associated with a spicy and rich sensation. In the context of the present invention, light tobacco varieties are tobacco varieties with a reducing sugar content of from about 2.5 percent to about 20 percent based on the dry weight of the leaf and a total ammonia content of less than about 0.12 percent based on the dry weight of the leaf. Reducing sugars include, for example, glucose or fructose. Total ammonia content includes, for example, ammonia and ammonia salts.

Dark tobacco varieties are tobacco varieties with typically large, dark-colored leaves. Throughout technical descriptions, the term "dark tobacco" is used for air-cured varieties of tobacco. Dark tobacco varieties may also be fermented. Tobacco varieties used primarily for chewing, snuff, cigars, and pipe blends are also included in this category. These dark tobacco varieties are typically air-cured and possibly fermented. Organoleptically, dark tobacco is a type of tobacco that, after curing, produces a sensation similar to that of dark cigars. Dark tobacco is characterized by a low sugar-to-nitrogen ratio. Examples of dark tobacco include Malawi Burley or other African Burley, dark-cured Brazilian Galpao, and sun- or air-cured Indonesian Kasturi. According to the present invention, dark tobacco varieties are tobacco varieties with a reducing sugar content of less than about 5 percent based on the dry weight of the leaf and a total ammonia content of up to about 0.5 percent based on the dry weight of the leaf.

Aromatic tobacco varieties are tobacco varieties that often have small, light-colored leaves. Throughout the description, the term "aromatic tobacco" is used to refer to other tobacco varieties characterized by a high content of aromatic compounds, such as essential oils. From an organoleptic perspective, aromatic tobacco is a type of tobacco that, after curing, produces a spicy and aromatic sensation. Examples of aromatic tobacco varieties include Greek Oriental, Turkish Oriental, and semi-Oriental tobaccos, as well as fire-cured tobaccos and American Burley tobaccos such as Perique, Shag, American Burley, or Maryland. Filler tobacco is not a specific type of tobacco, but includes types of tobacco that are primarily used to complement other types of tobacco used in a blend and that do not impart a specific, distinctive aromatic quality to the final product. Examples of filler tobacco include the stems, midribs, or petioles of other types of tobacco. A specific example is the flue-cured stems from the lower petioles of the Brazilian flue-cured tobacco species.

The cut filler suitable for use in the present invention may generally resemble the cut filler used in conventional smoking articles. The cut filler's cut width is preferably between 0.3 millimeters and 2.0 millimeters, more preferably between 0.5 millimeters and 1.2 millimeters, and most preferably between 0.6 millimeters and 0.9 millimeters. The cut width can play a role in heat distribution within the aerosol-generating element. The cut width can also play a role in the draw resistance of the article. Furthermore, the cut width can affect the overall density of the aerosol-generating substrate as a whole.

The length of the threads of the cut filler is somewhat random, as the thread length will depend on the overall size of the object from which the thread is cut. However, by maintaining appropriate material conditions before cutting, for example by controlling the moisture content and overall fineness of the material, longer threads can be cut. Preferably, the threads have a length of from approximately 10 millimeters to approximately 40 millimeters before combining the threads to form the aerosol-generating element. Obviously, if the threads are located in the aerosol-generating element in a longitudinal extension where the longitudinal extension of a section is less than 40 millimeters, the final aerosol-generating element may contain threads that are, on average, shorter than the length of the original thread. Preferably, the length of the thread of the cut filler is such that from approximately 20 percent to 60 percent of the threads extend along the entire length of the aerosol-generating element. This prevents the threads from easily separating from the aerosol-generating element.

In preferred embodiments, the weight of the cut filler is from 80 milligrams to 400 milligrams, preferably from 150 milligrams to 250 milligrams, and more preferably from 170 milligrams to 220 milligrams. This amount of cut filler generally provides sufficient material to generate an aerosol. Additionally, in light of the aforementioned diameter and size limitations, this ensures a balanced density of the aerosol-generating element between energy absorption, draw resistance, and fluid passages within the aerosol-generating element, where the aerosol-generating substrate contains plant material.

Preferably, the cut filler is impregnated with an aerosol-forming agent. Impregnation of the cut filler can be accomplished by spraying or other suitable application methods. The aerosol-forming agent can be added to the mixture during the preparation of the cut filler. For example, the aerosol-forming agent can be added to the mixture in a direct-conditioning cylinder (DCCC). Conventional equipment can be used to add the aerosol-forming agent to the cut filler. The aerosol-forming agent can be any suitable known compound or mixture of compounds that, when used, facilitates the formation of a dense and stable aerosol. The aerosol-forming agent can ensure that the aerosol is substantially resistant to thermal degradation at temperatures typically encountered during use of the aerosol-generating article. Suitable aerosol forming substances are, for example: polyhydric alcohols, such as, for example, triethylene glycol, 1,3-butanediol, propylene glycol and glycerol; esters of polyhydric alcohols, such as, for example, glycerol mono-, di- or triacetate; aliphatic esters of mono-, di- or polycarboxylic acids, such as, for example, dimethyl dodecanedioate and dimethyl tetradecanedioate; and combinations thereof.

Preferably, the aerosol forming agent comprises one or more of glycerin and propylene glycol. The aerosol forming agent may consist of glycerin or propylene glycol, or a combination of glycerin and propylene glycol.

Preferably, the amount of aerosol forming agent is from 6 percent to 20 percent by weight based on the dry weight of the cut filler, more preferably, the amount of aerosol forming agent is from 8 percent to 18 percent by weight based on the dry weight of the cut filler, and most preferably, the amount of aerosol forming agent is from 10 percent to 15 percent by weight based on the dry weight of the cut filler. When the aerosol forming agent is added to the cut filler in the amounts described above, the cut filler can become relatively adhesive. This advantageously helps to hold the cut filler in a predetermined location within the article, since the particles of cut filler tend to adhere to surrounding particles of cut filler, as well as to surrounding surfaces (for example, the inner surface of the wrapper surrounding the cut filler).

In some embodiments, the target amount of aerosol-forming agent is approximately 13 percent by weight, based on the dry weight of the cut filler. The most effective amount of aerosol-forming agent will also depend on the cut filler, whether the cut filler contains plant leaf blades or homogenized plant material. For example, among other factors, the type of cut filler will determine the extent to which the aerosol-forming agent can facilitate the release of substances from the cut filler.

For these reasons, an aerosol-generating element containing cut filler, as described above, is capable of efficiently generating sufficient aerosol quantities at relatively low temperatures. Temperatures of 150 to 200 degrees Celsius in the heating chamber are sufficient for such cut filler alone to generate sufficient aerosol quantities, whereas aerosol-generating devices using sheets of molded tobacco leaf typically employ temperatures of approximately 250 degrees Celsius.

An additional benefit of operating at lower temperatures is that the need for aerosol cooling is reduced. Since low temperatures are typically used, a simpler cooling function may be sufficient. This, in turn, allows for a simpler and less complex design of the aerosol-generating device.

As briefly described above, when the aerosol generating substrate comprises homogenized plant material, the homogenized plant material may be provided in the form of one or more sheets.

Each of the one or more sheets described herein may individually have a thickness of between approximately 100 micrometers and 600 micrometers, preferably between 150 micrometers and 300 micrometers, and most preferably between 200 micrometers and 250 micrometers. Individual thickness refers to the thickness of an individual sheet, while the cumulative thickness refers to the total thickness of all sheets that make up the aerosol-generating substrate. For example, if the aerosol-generating substrate is formed from two individual sheets, the cumulative thickness is the sum of the thicknesses of the two individual sheets or the measured thickness of the two sheets when the two sheets are stacked on top of each other in the aerosol-generating substrate.

Each of the one or more sheets as described herein may individually have a grammage of from about 100 grams per square meter to about 600 grams per square meter.

Each of the one or more sheets as described herein may individually have a density of from about 0.3 grams per cubic centimeter to about 1.3 grams per cubic centimeter, and preferably from about 0.7 grams per cubic centimeter to about 1.0 grams per cubic centimeter.

In embodiments of the present invention in which the aerosol-generating substrate comprises one or more sheets of homogenized plant material, the sheets are preferably in the form of one or more assembled sheets. As used herein, the term "assembled" is used to describe a sheet of homogenized plant material that is rolled, folded, or otherwise compressed or narrowed in a direction substantially transverse to the cylindrical axis of the plug or rod.

One or more sheets of homogenized plant material may be collected transversely relative to its longitudinal axis and surrounded by a wrapper to form a continuous rod or plug.

One or more sheets of homogenized plant material may advantageously be corrugated or similarly treated. As used herein, the term "corrugated" refers to a sheet having a plurality of substantially parallel folds or corrugations. Alternatively, or in addition to corrugation, one or more sheets of homogenized plant material may be embossed, blind-embossed, perforated, or otherwise deformed to provide texture on one or both sides of the sheet.

Preferably, each sheet of homogenized plant material can be corrugated such that it has a plurality of folds or corrugations substantially parallel to the cylindrical axis of the plug. This treatment advantageously facilitates the collection of the corrugated sheet of homogenized plant material to form the plug. Preferably, one or more sheets of homogenized plant material can be collected. It will be understood that the corrugated sheets of homogenized plant material can have a plurality of substantially parallel folds or corrugations located at an acute or obtuse angle to the cylindrical axis of the plug. The sheet can be corrugated to such a degree that the integrity of the sheet is disrupted at a plurality of parallel folds or corrugations, which causes material separation and leads to the formation of pieces, threads, or strips of homogenized plant material.

Alternatively, one or more sheets of homogenized plant material can be cut into threads, as mentioned above. In such embodiments, the aerosol-generating substrate comprises a plurality of threads of homogenized plant material. The threads can be used to form a plug. Typically, the width of such threads is approximately 5 millimeters, or approximately 4 millimeters, or approximately 3 millimeters, or approximately 2 millimeters, or less. The length of the threads can be greater than approximately 5 millimeters, from approximately 5 millimeters to approximately 15 millimeters, from approximately 8 millimeters to approximately 12 millimeters, or approximately 12 millimeters. Preferably, the threads have substantially the same length relative to one another.

The homogenized plant material may contain up to about 95 percent by weight of plant particles on a dry weight basis. Preferably, the homogenized plant material contains up to about 90 percent by weight of plant particles, more preferably up to about 80 percent by weight of plant particles, more preferably up to about 70 percent by weight of plant particles, more preferably up to about 60 percent by weight of plant particles, more preferably up to about 50 percent by weight of plant particles on a dry weight basis.

For example, the homogenized plant material may contain from about 2.5 percent to about 95 percent by weight of plant particles, or from about 5 percent to about 90 percent by weight of plant particles, or from about 10 percent to about 80 percent by weight of plant particles, or from about 15 percent to about 70 percent by weight of plant particles, or from about 20 percent to about 60 percent by weight of plant particles, or from about 30 percent to about 50 percent by weight of plant particles on a dry weight basis.

In certain embodiments of the present invention, the homogenized plant material is a homogenized tobacco material containing tobacco particles. Sheets of homogenized tobacco material for use in such embodiments of the present invention may have a tobacco content of at least about 40 percent by weight on a dry weight basis, more preferably at least about 50 percent by weight on a dry weight basis, more preferably at least about 70 percent by weight on a dry weight basis, and most preferably at least about 90 percent by weight on a dry weight basis.

For the purposes of the present invention, the term "tobacco particles" describes particles of any plant belonging to the genus Nicotiana. The term "tobacco particles" encompasses ground or powdered tobacco leaf lamellas, ground or powdered tobacco leaf stems, tobacco dust, tobacco fines, and other particulate tobacco by-products generated during the processing, handling, and shipping of tobacco. In a preferred embodiment, the tobacco particles are substantially all derived from tobacco leaf lamellas. In contrast, separated nicotine and nicotine salts are compounds derived from tobacco but are not considered tobacco particles for the purposes of the present invention and are not included in the percentage of particulate plant material.

The aerosol-generating substrate may further comprise one or more aerosol-forming agents. Upon vaporization, the aerosol-forming agent may carry other vaporized compounds released from the aerosol-generating substrate upon heating, such as nicotine and flavorings, in the aerosol. Aerosol-forming agents 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 dimethyl tetradecanedioate.

The aerosol-generating substrate may have an aerosol-forming substance content of from about 5 percent to about 30 percent by weight on a dry weight basis, such as from about 10 percent to about 25 percent by weight on a dry weight basis, or from about 15 percent to about 20 percent by weight on a dry weight basis.

For example, if the substrate is intended for use in an aerosol-generating article for an electric aerosol-generating system having a heating element, it may preferably comprise an aerosol-forming agent content of from about 5 percent to about 30 percent by weight, based on the dry weight. If the substrate is intended for use in an aerosol-generating article for an electric aerosol-generating system having a heating element, the aerosol-forming agent is preferably glycerol.

In other embodiments, the aerosol-generating substrate may have an aerosol-forming agent content of from about 1 percent to about 5 percent by weight on a dry weight basis. For example, if the substrate is intended for use in an aerosol-generating article in which the aerosol-forming agent is retained in a reservoir separate from the substrate, the substrate may have an aerosol-forming agent content of greater than 1 percent and less than about 5 percent. In such embodiments, the aerosol-forming agent is vaporized upon heating, and a stream of the aerosol-forming agent contacts the aerosol-generating substrate to entrain flavoring agents from the aerosol-generating substrate in the aerosol.

In other embodiments, the aerosol-generating substrate may have an aerosol-forming agent content of from about 30 percent by weight to about 45 percent by weight. This relatively high level of aerosol-forming agent is particularly suitable for aerosol-generating substrates that are intended to be heated at a temperature of less than 275 degrees Celsius. In such embodiments, the aerosol-generating substrate preferably further comprises from about 2 percent by weight to about 10 percent by weight of a cellulose ether on a dry weight basis and from about 5 percent by weight to about 50 percent by weight of additional cellulose on a dry weight basis. It has been found that the use of a combination of a cellulose ether and additional cellulose provides particularly effective aerosol delivery when used in an aerosol-generating substrate having an aerosol-forming agent content of from 30 percent by weight to 45 percent by weight.

Suitable cellulose ethers include, but are not limited to, methylcellulose, hydroxypropylmethylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, ethylhydroxyethylcellulose, and carboxymethylcellulose (CMC). In particularly preferred embodiments, the cellulose ether is carboxymethylcellulose.

As used herein, the term "additional cellulose" encompasses any cellulosic material included in the aerosol-generating substrate that does not originate from non-tobacco plant particles or tobacco particles present in the aerosol-generating substrate. Therefore, additional cellulose is included in the aerosol-generating substrate in addition to the non-tobacco plant material or tobacco material as a source of cellulose separate and distinct from any cellulose inherently present in the non-tobacco plant particles or tobacco particles. The additional cellulose typically originates from a plant other than the non-tobacco plant particles or tobacco particles. Preferably, the additional cellulose is in the form of an inert cellulose material that is inert to the senses and therefore does not significantly affect the organoleptic characteristics of the aerosol generated from the aerosol-generating substrate. For example, the additional cellulose is preferably a tasteless and odorless material.

Supplemental cellulose may contain cellulose powder, cellulose fibers, or a combination of both.

The aerosol forming agent can act as a humectant in the aerosol generating substrate.

The wrapper surrounding the rod of homogenized plant material may be a paper wrapper or a non-paper wrapper. Paper wrappers suitable for use in certain embodiments of the present invention are known in the art and include, but are not limited to, cigarette papers and filter papers. Non-paper wrappers suitable for use in certain embodiments of the present invention are known in the art and include, but are not limited to, sheets of homogenized tobacco materials. In certain preferred embodiments, the wrapper may be formed from a laminated material comprising multiple layers. Preferably, the wrapper is formed from a multi-layer sheet comprising a layer of aluminum. The use of a multi-layer sheet containing aluminum advantageously prevents combustion of the aerosol-generating substrate in the event that the aerosol-generating substrate is to be ignited rather than heated in the intended manner.

In certain alternative embodiments of the present invention, the aerosol-generating substrate comprises a gel composition that contains an alkaloid compound, a cannabinoid compound, or both an alkaloid compound and a cannabinoid compound. In particularly preferred embodiments, the aerosol-generating substrate comprises a gel composition that contains nicotine.

Preferably, the gel composition comprises an alkaloid compound or a cannabinoid compound, or both an alkaloid compound and a cannabinoid compound; an aerosol forming agent; and at least one gelling agent. Preferably, the at least one gelling agent forms a solid medium, and glycerol is distributed in the solid medium, wherein the alkaloid or cannabinoid is distributed in the glycerol. Preferably, the gel composition is a stable gel phase.

A stable nicotine-containing gel composition provides a predictable shape during storage or transportation from production to the consumer. A stable nicotine-containing gel composition essentially maintains its shape. A stable nicotine-containing gel composition essentially does not release its liquid phase during storage or transportation from production to the consumer. A stable nicotine-containing gel composition can provide a simple disposable design. This disposable component can be designed without liquid, thus allowing for a wider range of container materials and designs.

The gel composition described herein can be combined with an aerosol-generating device to deliver nicotine aerosol to the lungs at inhalation or airflow rates within the range of inhalation or airflow rates during normal smoking. The aerosol-generating device can continuously heat the gel composition. The user can take multiple inhalations, or "puffs," with each "puff" delivering a specific amount of nicotine aerosol. The gel composition can be capable of delivering a high-nicotine/low-total-particulate-content (TPC) aerosol to the user upon heating, preferably in a continuous manner.

The phrase "stable gel phase" or "stable gel" refers to a gel that substantially maintains its shape and mass when exposed to various environmental conditions. A stable gel may not release (release moisture) or absorb water when exposed to standard temperature and pressure with relative humidity ranging from approximately 10 percent to approximately 60 percent. For example, a stable gel may substantially maintain its shape and mass when exposed to standard temperature and pressure with relative humidity ranging from approximately 10 percent to approximately 60 percent.

The gel composition contains an alkaloid compound, a cannabinoid compound, or both an alkaloid compound and a cannabinoid compound. The gel composition may contain one or more alkaloids. The gel composition may contain one or more cannabinoids. The gel composition may contain a combination of one or more alkaloids and one or more cannabinoids.

The term "alkaloid compound" refers to any of a class of naturally occurring organic compounds that contain one or more basic nitrogen atoms. Typically, an alkaloid contains at least one nitrogen atom in an amine-type structure. This or another nitrogen atom in the alkaloid compound molecule can be active as a base in acid-base reactions. Most alkaloid compounds have one or more nitrogen atoms as part of a cyclic system, such as a heterocyclic ring. In nature, alkaloid compounds are found primarily in plants and are particularly common in certain families of flowering plants. However, some alkaloid compounds are found in animal species and fungi. In this specification, the term "alkaloid compound" refers to both naturally occurring alkaloid compounds and synthetically produced alkaloid compounds.

The gel composition may preferably contain an alkaloid compound selected from the group consisting of nicotine, anatabine, and combinations thereof.

Preferably, the gel composition contains nicotine.

The term "nicotine" refers to nicotine and nicotine derivatives such as pure nicotine, nicotine salts, etc.

The term "cannabinoid compound" refers to any of a class of naturally occurring compounds found in parts of the cannabis plant, specifically those belonging to the species Cannabis sativa, Cannabis indica, and Cannabis ruderalis. Cannabinoid compounds are particularly concentrated in the female flower heads. Cannabinoid compounds naturally occurring in the cannabis plant include cannabidiol (CBD) and tetrahydrocannabinol (THC). In this specification, the term "cannabinoid compounds" is used to describe both naturally occurring cannabinoid compounds and synthetically produced cannabinoid compounds.

Embodiments of the present invention in which the aerosol-generating element comprises an aerosol-generating substrate containing a gel composition, as described above, may advantageously comprise an upstream element located upstream of the aerosol-generating element. In this case, the upstream element advantageously prevents physical contact with the gel composition. The upstream element may also advantageously compensate for any potential decrease in RTD, for example, due to evaporation of the gel composition when the aerosol-generating element heats up during use. Additional details on the provision of one such upstream element will be described below.

The downstream section may have any length. The downstream section may have a length of at least approximately 10 millimeters. For example, the downstream section may have a length of at least approximately 15 millimeters, at least approximately 20 millimeters, at least approximately 25 millimeters, or at least approximately 30 millimeters.

Providing a downstream section with a length greater than the values specified above can advantageously provide space for the aerosol to cool and condense before reaching the consumer. This can also ensure separation of the user from the heating element when the aerosol-generating device is used in conjunction with an aerosol-generating device.

The downstream section may have a length no greater than approximately 60 millimeters. For example, the downstream section may have a length no greater than approximately 50 millimeters, no greater than approximately 55 millimeters, no greater than approximately 40 millimeters, or no greater than approximately 35 millimeters.

The downstream section may have a length of approximately 10 millimeters to approximately 60 millimeters, approximately 15 millimeters to approximately 50 millimeters, approximately 20 millimeters to approximately 55 millimeters, approximately 25 millimeters to approximately 40 millimeters, or approximately 30 millimeters to approximately 35 millimeters. For example, the downstream section may have a length of approximately 33 millimeters.

The ratio between the length of the downstream section and the length of the aerosol generating substrate may be from about 1.0 to about 4.5.

Preferably, the ratio between the length of the downstream section and the length of the aerosol-generating substrate is at least about 1.5, more preferably at least about 2.0, even more preferably at least about 2.5. In preferred embodiments, the ratio between the length of the downstream section and the length of the aerosol-generating substrate is less than about 4.0, more preferably less than about 3.5, even more preferably less than about 3.0.

In some embodiments, the ratio between the length of the downstream section and the length of the aerosol generating substrate is from about 1.5 to about 4.0, preferably from about 2.0 to about 3.5, more preferably from about 2.5 to about 3.0.

In particularly preferred embodiments, the ratio between the length of the downstream section and the length of the aerosol generating substrate is approximately 2.75.

The ratio between the length of the downstream section and the overall length of the aerosol generating article may be from about 0.1 to about 1.5.

Preferably, the ratio between the length of the downstream section and the total length of the aerosol-generating article is at least about 0.25, more preferably at least about 0.50. The ratio between the length of the downstream section and the total length of the aerosol-generating article is preferably less than about 1.25, more preferably less than about 1.0.

In some embodiments, the ratio between the length of the downstream section and the overall length of the aerosol generating article is preferably from about 0.25 to about 1.25, more preferably from about 0.5 to about 1.0.

In a particularly preferred embodiment, the ratio between the length of the downstream section and the overall length of the aerosol generating article is approximately 0.73 or approximately 0.64.

The length of the downstream section may consist of the sum of the lengths of the individual components that make up the downstream section.

The RTD of the downstream section may be no more than approximately 100 mm H2O. For example, the RTD of the downstream section may be no more than approximately 50 mm H2O, no more than approximately 25 mm H2O, no more than approximately 15 mm H2O, no more than approximately 10 mm H2O, no more than approximately 8 mm H2O, no more than approximately 5 mm H2O, or no more than approximately 1 mm H2O.

The downstream section may comprise an unobstructed path for air flow from the downstream end of the aerosol generating substrate to the downstream end of the downstream section.

The unobstructed airflow path from the downstream end of the aerosol-generating substrate to the downstream end of the downstream section has a minimum diameter of approximately 0.5 millimeters. For example, the unobstructed airflow path may have a minimum diameter of 1 millimeter, 2 millimeters, 3 millimeters, or 5 millimeters.

The downstream section may comprise a hollow tubular element.

Providing a hollow tubular member can advantageously achieve the desired overall length of the aerosol generating article without unacceptably increasing the draw resistance.

A hollow tubular element may extend from the downstream end of a downstream section to the upstream end of the downstream section. In other words, the entire length of the downstream section may be comprised of a hollow tubular element. When this occurs, it will be understood that the lengths and length ratios established above relative to the downstream section apply equally to the length of the hollow tubular element.

The hollow tubular member may be adjacent to a downstream end of the aerosol generating article.

The hollow tubular element may be located at a distance from the downstream end of the aerosol-generating article. When this occurs, there may be a void between the downstream end of the aerosol-generating substrate and the upstream end of the hollow tubular element.

A hollow tubular element may have an internal diameter. The hollow tubular element may have a constant internal diameter along its length. The internal diameter of the hollow tubular element may vary along its length.

The hollow tubular element may have an internal diameter of at least approximately 2 millimeters. For example, the hollow tubular element may have an internal diameter of at least approximately 4 millimeters, at least approximately 5 millimeters, or at least approximately 7 millimeters.

Providing a hollow tubular member having an inner diameter as set forth above can advantageously ensure sufficient rigidity and strength for the hollow tubular member.

The hollow tubular element may have an internal diameter of no more than approximately 10 millimeters. For example, the hollow tubular element may have an internal diameter of no more than approximately 9 millimeters, no more than approximately 8 millimeters, or no more than approximately 7.5 millimeters.

Providing a hollow tubular member having an inner diameter as specified above can advantageously reduce the tightening resistance of the hollow tubular member.

The hollow tubular member may have an internal diameter of from about 2 millimeters to about 10 millimeters, from about 4 millimeters to about 9 millimeters, from about 5 millimeters to about 8 millimeters, or from about 7 millimeters to about 7.5 millimeters.

The hollow tubular element may have an internal diameter of approximately 7.1 millimeters.

The ratio between the inner diameter of the hollow tubular element and the outer diameter of the hollow tubular element may be at least approximately 0.8. For example, the ratio between the inner diameter of the hollow tubular element and the outer diameter of the hollow tubular element may be at least approximately 0.85, at least approximately 0.9, or at least approximately 0.95.

The ratio between the inner diameter of the hollow tubular element and the outer diameter of the hollow tubular element may be no more than approximately 0.99. For example, the ratio between the inner diameter of the hollow tubular element and the outer diameter of the hollow tubular element may be no more than approximately 0.98.

The ratio between the inner diameter of the hollow tubular member and the outer diameter of the hollow tubular member may be approximately 0.97.

Providing a relatively large inner diameter can advantageously reduce the tightening resistance of the hollow tubular member.

The lumen of a hollow tubular element may have any cross-sectional shape. The lumen of a hollow tubular element may have a circular cross-sectional shape.

The hollow tubular element may be formed from any material. For example, the hollow tubular element may comprise cellulose acetate tow. When the hollow tubular element comprises cellulose acetate tow, the hollow tubular element may have a thickness of approximately 0.1 millimeters to approximately 1 millimeter. The hollow tubular element may have a thickness of approximately 0.5 millimeters.

When the hollow tubular member comprises cellulose acetate tow, the cellulose acetate tow may have a denier per filament of from about 2 to about 4 and a total denier of from about 25 to about 40.

The hollow tubular element may comprise paper. The hollow tubular element may comprise at least one layer of paper. The paper may be very rigid paper. The paper may be corrugated paper, such as corrugated heat-resistant paper or corrugated parchment paper. The paper may be cardboard. The hollow tubular element may be a paper tube. The hollow tubular element may be a tube formed from spirally wound paper. The hollow tubular segment may be formed from multiple layers of paper. The paper may have a basis weight of at least about 50 grams per square meter, at least about 60 grams per square meter, at least about 70 grams per square meter, or at least about 90 grams per square meter.

When the tubular segment comprises paper, the paper may have a thickness of at least about 50 micrometers. For example, the paper may have a thickness of at least about 70 micrometers, at least about 90 micrometers, or at least about 100 micrometers.

The hollow tubular element may contain a polymer. For example, the hollow tubular element may contain a polymer film. The polymer film may comprise a cellulose film. The hollow tubular element may contain low-density polyethylene (LDPE) or polyhydroxyalkanoate (PHA) fibers.

The downstream section may comprise a modified tubular element. The modified tubular element may be provided in place of a hollow tubular element. The modified tubular element may be provided immediately downstream of the aerosol-generating substrate. The modified tubular element may abut the aerosol-generating substrate.

The modified tubular element may comprise a tubular main portion defining a cavity extending from a first upstream end of the tubular main portion to a second downstream end of the tubular main portion. The modified tubular element may also comprise a bent end portion defining a first end wall at the first upstream end of the tubular main portion. The first end wall may define the boundaries of an opening that permits airflow between the cavity and the exterior of the modified tubular element. Preferably, the opening is configured to permit airflow from the aerosol-generating substrate to pass through the opening into the cavity.

The cavity of the tubular core may be substantially empty to provide substantially unimpeded airflow along the cavity. The RTD of the modified tubular element may be localized at a specific longitudinal position of the modified tubular element. In particular, the RTD of the modified tubular element may be localized at the first end wall. In this way, the RTD of the modified tubular element can be substantially controlled by the selected configuration of the first end wall and the corresponding opening. The RTD of the modified tubular element (which is essentially the RTD of the first end wall) may be approximately 5 millimeters of water.

The modified tubular element may have any length. The modified tubular element may have a length from approximately 10 millimeters to approximately 60 millimeters, from approximately 15 millimeters to approximately 50 millimeters, from approximately 20 millimeters to approximately 55 millimeters, from approximately 25 millimeters to approximately 40 millimeters, or from approximately 30 millimeters to approximately 35 millimeters. For example, the modified tubular element may have a length of approximately 33 millimeters.

The modified tubular element may have any outside diameter (D _E ). The modified tubular element may have an outside diameter (D _E ) from approximately 5 millimeters to approximately 12 millimeters, from approximately 6 millimeters to approximately 12 millimeters, or from approximately 7 millimeters to approximately 12 millimeters. The modified tubular element may have an outside diameter (D _E ) of approximately 7.3 millimeters.

The modified tubular element may have any inner diameter ( _DI ). The modified tubular element may have an inner diameter ( _DI ) of approximately 2 millimeters to approximately 10 millimeters, approximately 4 millimeters to approximately 9 millimeters, approximately 5 millimeters to approximately 8 millimeters, or approximately 7 millimeters to approximately 7.5 millimeters. The modified tubular element may have an inner diameter ( _DI ) of approximately 7.1 millimeters.

The modified tubular element may have a peripheral wall of any thickness. The peripheral wall of the modified tubular element may have a thickness of between approximately 0.05 millimeters and approximately 0.5 millimeters. The peripheral wall of the modified tubular element may have a thickness of approximately 0.1 millimeters.

The downstream section may contain ventilation. Ventilation may be provided to allow cooler air from outside the aerosol-generating product to enter the interior of the downstream section.

The aerosol generating article may typically have a ventilation level of at least about 10 percent, preferably at least about 20 percent.

In preferred embodiments, the aerosol-generating article has a ventilation level of at least about 20 percent, or 25 percent, or 30 percent. More preferably, the aerosol-generating article has a ventilation level of at least about 35 percent.

The aerosol-generating article preferably has a ventilation level of less than approximately 80 percent. More preferably, the aerosol-generating article has a ventilation level of less than approximately 60 percent or less than approximately 50 percent.

An aerosol generating product can typically have a ventilation level from approximately 10 percent to approximately 80 percent.

In some embodiments, the aerosol-generating article has a ventilation level of from about 20 percent to about 80 percent, preferably from about 20 percent to about 60 percent, more preferably from about 20 percent to about 50 percent. In other embodiments, the aerosol-generating article has a ventilation level of from about 25 percent to about 80 percent, preferably from about 25 percent to about 60 percent, more preferably from about 25 percent to about 50 percent. In further embodiments, the aerosol-generating article has a ventilation level of from about 30 percent to about 80 percent, preferably from about 30 percent to about 60 percent, more preferably from about 30 percent to about 50 percent.

In particularly preferred embodiments, the aerosol-generating article has a ventilation level of between approximately 40 percent and approximately 50 percent. In some particularly preferred embodiments, the aerosol-generating article has a ventilation level of approximately 45 percent.

Without being limited by theory, the present inventors have found that a temperature drop caused by introducing cooler external air into a hollow tubular member can have a beneficial effect on the nucleation and growth of aerosol particles.

The formation of an aerosol from a gaseous mixture containing various chemical compounds depends on the subtle interactions of nucleation, evaporation, condensation, and droplet coalescence, while simultaneously accounting for changes in concentration, temperature, and vapor velocity fields. The so-called classical nucleation theory is based on the assumption that the fraction of molecules in the gas phase is large enough to remain cohesive for a long time with a sufficient probability (e.g., a probability of 0.5 in 1). These molecules represent a kind of critical threshold molecular clusters among transient molecular aggregates, meaning that, on average, smaller molecular clusters are more likely to disintegrate sufficiently quickly into the gas phase, while larger clusters are, on average, more likely to grow. Such a critical cluster is identified as the key nucleation nucleus, from which droplet growth is expected due to the condensation of molecules from the vapor. Primary droplets, which have just formed, are assumed to appear with a certain initial diameter and can then grow by several orders of magnitude. This is simplified and can be accelerated by rapid cooling of the surrounding vapor, which causes condensation. In this regard, it should be remembered that evaporation and condensation are two sides of the same mechanism: mass transfer between gas and liquid. While evaporation refers to the net mass transfer from liquid droplets to the gas phase, condensation is the net mass transfer from the gas phase to the droplet phase. Evaporation (or condensation) will cause a decrease in volume (or growth) of droplets, but will not change the number of droplets.

In this scenario, which may be further complicated by droplet coalescence, temperature and cooling rate may play a significant role in determining the system's response. In general, different cooling rates may lead to significantly different temporal behavior regarding liquid phase (droplet) formation, as the nucleation process is typically nonlinear. Without being limited by theory, it is hypothesized that cooling may cause a rapid decrease in droplet number concentration, followed by a strong, short-term increase in droplet growth (nucleation burst). This nucleation burst may be more significant at lower temperatures. Furthermore, it may be that higher cooling rates may promote an earlier onset of nucleation. Conversely, a decrease in the cooling rate may have a beneficial effect on the final size attained by aerosol droplets.

Thus, the rapid cooling caused by introducing outside air into a hollow tubular element can be beneficially used to promote the nucleation and growth of aerosol droplets. However, a direct disadvantage of introducing outside air into a hollow tubular element is the dilution of the aerosol stream delivered to the consumer.

The present inventors have surprisingly discovered that the dilution effect on the aerosol, which can be measured, particularly the effect on the delivery of an aerosol-forming substance (such as glycerol) incorporated into the aerosol-generating substrate, is advantageously minimized when the ventilation level is within the ranges described above. Specifically, ventilation levels of 25 percent to 50 percent, and even more preferably 28 to 42 percent, were found to result in particularly satisfactory glycerol delivery values. At the same time, nucleation time and, consequently, the delivery of nicotine and an aerosol-forming substance (such as glycerol) are improved.

Ventilation into a downstream section may be provided along substantially the entire length of the downstream section. When this occurs, the downstream section may comprise a porous material that allows air to enter the downstream section. For example, when the downstream section comprises a hollow tubular element, the hollow segment may be formed from a porous material that allows air to enter the interior of the hollow tubular element. When the downstream section comprises a wrapper, the wrapper may be formed from a porous material that allows air to enter the interior of the hollow tubular element.

The downstream section may comprise a first ventilation zone for providing ventilation to the downstream section. The first ventilation zone comprises a portion of the downstream section through which a greater volume of air can flow than the remainder of the downstream section. For example, the first ventilation zone may comprise a portion of the downstream section with a higher porosity than the remainder of the downstream section.

The first ventilation zone may comprise a porous portion of a downstream section with a ventilation of at least 5 percent. For example, the first ventilation zone may comprise a porous portion of a downstream section with a ventilation of at least 10 percent, at least 20 percent, at least 25 percent, at least 30 percent, or at least 35 percent.

The first ventilation zone may comprise a porous portion of a downstream section with ventilation of no more than 80 percent. For example, the first ventilation zone may comprise a porous portion of a downstream section with ventilation of no more than 60 percent or less than 50 percent.

The first ventilation zone may comprise a porous portion of the downstream section with a ventilation of 10 percent to 80 percent, 20 percent to 80 percent, 20 percent to 60 percent, or 20 percent to 50 percent. In other embodiments, the first ventilation zone may comprise a porous portion of the downstream section with a ventilation of 25 percent to 80 percent, 25 percent to 60 percent, or 25 percent to 50 percent. In further embodiments, the first ventilation zone may comprise a porous portion of the downstream section with a ventilation of 30 percent to 80 percent, 30 percent to 60 percent, or 30 percent to 50 percent.

The first ventilation zone may comprise a porous portion of a downstream section with a ventilation rate of 40 percent to 50 percent. In some particularly preferred embodiments, the first ventilation zone may comprise a porous portion of a downstream section with a ventilation rate of 45 percent.

The first ventilation zone may comprise a first line of perforations surrounding a downstream section.

In some embodiments, the first ventilation zone may comprise two annular rows of perforations. For example, the perforations may be formed on a production line during the manufacturing of an aerosol-generating article. Each annular row of perforations may comprise from approximately 5 to approximately 40 perforations; for example, each annular row of perforations may comprise from approximately 8 to approximately 30 perforations.

When the aerosol-generating article comprises a connecting liner, the ventilation zone preferably comprises at least one corresponding annular row of perforations provided through a portion of the connecting liner. These may also be formed on a production line during the manufacturing of the smoking article. Preferably, the annular row or rows of perforations provided through a portion of the connecting liner are substantially aligned with the row or rows of perforations through a downstream section.

If the aerosol-generating article comprises a strip of tipping paper, wherein the strip of tipping paper extends over an annular row or rows of perforations in a downstream section, the ventilation zone preferably comprises at least one corresponding annular row of perforations provided through the strip of tipping paper. These may also be formed on a production line during the manufacturing of the smoking article. Preferably, the annular row or rows of perforations provided through the strip of tipping paper are substantially aligned with the row or rows of perforations through the downstream section.

The first line of perforations may comprise at least one perforation with a width of at least approximately 50 micrometers. For example, the first line of perforations may comprise at least one perforation with a width of at least approximately 65 micrometers, at least approximately 80 micrometers, at least approximately 90 micrometers, or at least approximately 100 micrometers.

The first line of perforations may comprise at least one perforation with a width no greater than approximately 200 micrometers. For example, the first line of perforations may comprise at least one perforation with a width no greater than approximately 175 micrometers, no greater than approximately 150 micrometers, no greater than approximately 125 micrometers, or no greater than approximately 120 micrometers.

The first line of perforations may comprise at least one perforation with a width of from about 50 micrometers to about 200 micrometers, from about 65 micrometers to about 175 micrometers, from about 90 micrometers to about 150 micrometers, or from about 100 micrometers to about 120 micrometers.

When perforations are formed using laser perforation techniques, the width of the perforation holes can be determined by the focal diameter of the laser.

The first line of perforations may comprise at least one perforation with a length of at least approximately 400 micrometers. For example, the first line of perforations may comprise at least one perforation with a length of at least approximately 425 micrometers, at least approximately 450 micrometers, at least approximately 475 micrometers, or at least approximately 500 micrometers.

The first line of perforations may comprise at least one perforation with a length no greater than approximately 1 millimeter. For example, the first line of perforations may comprise at least one perforation with a length no greater than approximately 950 micrometers, no greater than approximately 900 micrometers, no greater than approximately 850 micrometers, or no greater than approximately 800 micrometers.

The first line of perforation holes may comprise at least one perforation hole with a length of from about 400 micrometers to about 1 millimeter, from about 425 micrometers to about 950 micrometers, from about 450 micrometers to about 900 micrometers, from about 475 micrometers to about 850 micrometers, or from about 500 micrometers to about 800 micrometers.

The first line of perforations may comprise at least one perforation with an opening area of at least approximately 0.01 square millimeters. For example, the first line of perforations may comprise at least one perforation with an opening area of at least approximately 0.02 square millimeters, at least approximately 0.03 square millimeters, or at least approximately 0.05 square millimeters.

The first line of perforations may comprise at least one perforation with an opening area of no greater than approximately 0.5 square millimeters. For example, the first line of perforations may comprise at least one perforation with an opening area of no greater than approximately 0.3 square millimeters, no greater than approximately 0.25 square millimeters, or no greater than approximately 0.1 square millimeters.

The first line of perforations may comprise at least one perforation with an opening area of from about 0.01 square millimeters to about 0.5 square millimeters, from about 0.02 square millimeters to about 0.3 square millimeters, from about 0.03 square millimeters to about 0.25 square millimeters, or from about 0.05 square millimeters to about 0.1 square millimeters. The first line of perforations may comprise at least one perforation with an opening area of from about 0.05 square millimeters to about 0.096 square millimeters.

As stated above, the aerosol generating article may comprise a wrapper surrounding at least a portion of the downstream section, the first ventilation zone may comprise a porous portion of the wrapper.

The wrapper may be a paper wrapper and the first ventilation zone may comprise a portion of porous paper.

As stated above, the downstream section may comprise a hollow tubular element located at a distance from the downstream end of the aerosol-generating substrate. When this is the case, the hollow tubular element may be connected to the aerosol-generating substrate by a paper wrapper. The wrapper may be a porous paper wrapper. When this is the case, the first ventilation zone may comprise a portion of the porous paper wrapper covering the space between the downstream end of the aerosol-generating substrate and the upstream end of the hollow tubular element. In this case, the upstream end of the first ventilation zone abuts the downstream end of the aerosol-generating substrate, and the downstream end of the first ventilation zone abuts the upstream end of the hollow tubular element.

The porous portion of the wrapper that forms part of the first ventilation zone may have a basis weight that is less than that of the portion of the wrapper that does not form part of the first ventilation zone.

The porous portion of the wrapper that forms the first ventilation zone may have a thickness that is less than that of the portion of the wrapper that does not form part of the first ventilation zone.

The upstream end of the first ventilation zone may be located less than 10 millimeters from the downstream end of the aerosol generating substrate.

For example, the upstream end of the first ventilation zone may be located less than 8 millimeters, less than 5 millimeters, less than 3 millimeters, or less than 1 millimeter from the downstream end of the aerosol generating substrate.

The upstream end of the first ventilation zone may be longitudinally aligned with the downstream end of the aerosol generating substrate.

The upstream end of the first ventilation zone may be located at a distance of less than 25 percent of the distance along the length of the downstream section from the downstream end of the aerosol-generating substrate. For example, the upstream end of the first ventilation zone may be located at a distance of less than 20 percent, less than 18 percent, less than 15 percent, less than 10 percent, less than 5 percent, or less than 1 percent of the distance along the length of the downstream section from the downstream end of the aerosol-generating substrate.

The downstream end of the first ventilation zone may be located at a distance of less than 30 percent of the distance along the length of the downstream section from the downstream end of the aerosol-generating substrate. For example, the downstream end of the first ventilation zone may be located at a distance of less than 25 percent, less than 20 percent, less than 18 percent, less than 15 percent, less than 10 percent, or less than 5 percent of the distance along the length of the downstream section from the downstream end of the aerosol-generating substrate.

The downstream end of the first ventilation zone may be located less than 10 millimeters from the downstream end of the aerosol-generating substrate. In other words, the first ventilation zone may be located entirely within 10 millimeters of the aerosol-generating substrate.

For example, the downstream end of the first ventilation zone may be located less than 8 millimeters, less than 5 millimeters, or less than 3 millimeters from the downstream end of the aerosol generating substrate.

The first ventilation zone may be located anywhere along the length of the downstream section. The downstream end of the first ventilation zone may be located no more than approximately 25 millimeters from the downstream end of the aerosol-generating article. For example, the first ventilation zone may be located no more than approximately 20 millimeters from the downstream end of the aerosol-generating article.

By arranging the first ventilation zone as described above, it is possible to advantageously prevent the first ventilation zone from being blocked when the aerosol-generating article is inserted into the aerosol-generating device.

The downstream end of the first ventilation zone may be located at a distance of at least approximately 8 millimeters from the downstream end of the aerosol-generating article. For example, the downstream end of the first ventilation zone may be located at a distance of at least approximately 10 millimeters, at least 12 millimeters, or at least approximately 15 millimeters from the downstream end of the aerosol-generating article.

By arranging the first ventilation zone as described above, it is possible to advantageously prevent the first ventilation zone from being obstructed by the mouth or lips of the user when the aerosol generating product is in use.

The downstream end of the first ventilation zone may be located at a distance of approximately 8 millimeters to approximately 25 millimeters, approximately 10 millimeters to approximately 25 millimeters, or approximately 15 millimeters to approximately 20 millimeters from the downstream end of the aerosol-generating article. The downstream end of the first ventilation zone may be located at a distance of approximately 18 millimeters from the downstream end of the aerosol-generating article.

The upstream end of the first ventilation zone may be located at least approximately 20 millimeters from the upstream end of the aerosol-generating article. For example, the upstream end of the first ventilation zone may be located at least approximately 25 millimeters from the upstream end of the aerosol-generating article.

By arranging the first ventilation zone as described above, it is possible to advantageously prevent the first ventilation zone from being blocked when the aerosol-generating article is inserted into the aerosol-generating device.

The upstream end of the first ventilation zone may be located no more than 37 millimeters from the upstream end of the aerosol-generating article. For example, the upstream end of the first ventilation zone may be located no more than approximately 30 millimeters from the upstream end of the aerosol-generating article.

By arranging the first ventilation zone as described above, it is possible to advantageously prevent the first ventilation zone from being obstructed by the mouth or lips of the user when the aerosol generating product is in use.

The upstream end of the first ventilation zone may be located at a distance of approximately 20 millimeters to approximately 37 millimeters, or approximately 25 millimeters to approximately 30 millimeters, from the upstream end of the aerosol-generating article. The upstream end of the first ventilation zone may be located at a distance of approximately 27 millimeters from the downstream end of the aerosol-generating article.

The first ventilation zone may have any length. The first ventilation zone may have a length of at least 0.5 millimeters. In other words, the longitudinal distance between the downstream end of the first ventilation zone and the upstream end of the first ventilation zone is at least 0.5 millimeters. For example, the first ventilation zone may have a length of at least 1 millimeter, at least 2 millimeters, at least 5 millimeters, or at least 8 millimeters.

The first ventilation zone may be no longer than 10 millimeters. For example, the first ventilation zone may be no longer than 8 millimeters or no longer than 5 millimeters.

The first ventilation zone can range in length from 0.5 millimeters to 10 millimeters. For example, the first ventilation zone can range in length from 1 millimeter to 8 millimeters or from 2 millimeters to 5 millimeters.

The aerosol-generating article may further comprise an additional element or component in addition to the hollow tubular element and the aerosol-generating element, such as a filter segment or a mouthpiece segment. More preferably, a downstream section of the aerosol-generating article may comprise an element or component in addition to the hollow tubular element, such as a filter segment or a mouthpiece segment.

Such an additional element may be located downstream of the hollow tubular element. Such an additional element may be located directly downstream of the hollow tubular element. Such an additional element may be located between the aerosol-generating element and the hollow tubular element. Such an additional element may extend from the downstream end of the hollow tubular element to the mouthpiece end of the aerosol-generating article, or to the downstream end of the downstream section. Such an additional element is preferably a downstream element or segment. Such an additional element may be a filter element or segment or a mouthpiece segment. Such an additional element may form part of the downstream section of the aerosol-generating article according to the present invention. Such an additional element may be in axial alignment with the remaining components of the aerosol-generating article, such as the aerosol-generating element and the hollow tubular element. Moreover, the additional element may have a diameter similar to the outer diameter of the hollow tubular element, the diameter of the aerosol generating element, or the diameter of the aerosol generating article.

The aerosol-generating article of the present invention preferably comprises a wrapper surrounding the downstream section (or components of the downstream section). Such a wrapper may be an outer rim wrapper that surrounds the downstream section and a portion of the aerosol-generating element, such that the downstream section is attached to the aerosol-generating element.

A downstream section of the aerosol generating article according to the present invention may form a recessed cavity.

The "additional element" described above may also be referred to in this specification as the "first section" or "first segment" of the "downstream section." The terms "first segment" or "additional element" may alternatively be referred to in this specification as a "mouthpiece segment," "retaining segment," "downstream segment," "mouthpiece element," "downstream element," "retaining element," "filter element," or "filter segment," or "downstream plug element." The term "mouthpiece" may refer to an element of an aerosol-generating article that is located downstream of the aerosol-generating element of the aerosol-generating article, preferably near the mouth-end of the article.

As mentioned above, from about 5 to about 35 percent of the length of the downstream section may comprise a first section that forms a first void for the passage of air, and at least about 65 percent of the length of the downstream section may comprise a second section that forms a second void for the passage of air, where the total cross-sectional area of the first void formed by the first section may be less than the total cross-sectional area of the second void formed by the second section. The inventors of the present invention have found that the longitudinal distribution of the first and second voids within the downstream section ensures that the downstream section achieves a relatively low RTD while simultaneously providing a downstream component (the first section) that does not significantly increase the RTD and provides a physical barrier that can prevent any material expelled from the aerosol-generating element from unintentionally escaping from the mouthpiece end of the aerosol-generating article during normal use.

The term "void section" refers to a section or space through which air can pass. For example, a hollow tubular element can form a cavity that provides a void section. An additional segment can contain multiple airflow channels formed through the segment, and these multiple airflow channels can form a void section within the additional segment for air to pass through. A filter segment or retaining segment, according to the present invention, can also provide a void section formed by multiple air gaps provided within the material forming the filter segment or retaining segment for air to pass through.

The first section, or portion, of a downstream section refers to the section, portion, or component of the downstream section that forms the first void or space. Similarly, the second section, or portion, of a downstream section refers to the section, portion, or component of the downstream section that forms the second void or space.

The first section of the downstream section may comprise one or more first segments according to the present invention. The first segment may comprise at least one air flow path of the segment extending along the longitudinal direction of the first segment. The first empty portion may be formed by at least one (first) air flow path of the segment. The at least one air flow path of the segment may be formed within and by the first section of the downstream section. In other words, when the first section comprises the first segment, at least one air flow path of the segment may be formed within and along the first segment of the downstream section. As discussed above, the first segment of the downstream section may comprise a mouthpiece segment. Preferably, the at least one air flow path of the segment extends along the entire length of the first segment, extending from the upstream end of the first segment to the downstream end of the first segment.

The second void may comprise at least one cavity. The at least one cavity may provide an unobstructed airflow channel extending along the longitudinal direction of the aerosol-generating article. The second section of the downstream section may comprise a second segment. The second segment may be a hollow tubular element according to the present invention. The second section of the downstream section may comprise at least one hollow tubular element. The second void may be formed by at least one hollow tubular element. Providing the majority of the length of the downstream section with at least one hollow tubular element ensures that the downstream section and the aerosol-generating article as a whole achieve a relatively low RTD.

The downstream section may comprise a second section containing two hollow tubular elements and a first section containing a first segment. The second void may be formed by two hollow tubular elements. The first section may be positioned between the two hollow tubular elements. The two hollow tubular elements may have different lengths or substantially the same length relative to each other. In such an example, the two cavities formed by the two hollow tubular elements (together) form the second void. The second void may be divided into multiple void sections.

Alternatively, the downstream section may comprise a second section comprising a hollow tubular element, and the first section comprises at least one first segment. The hollow tubular element may extend from the downstream end of the aerosol-generating element to the mouthpiece end of the aerosol-generating article. At least one first segment of the first section may be located within and along the hollow tubular element. The at least one first segment may, therefore, divide the cavity formed by the hollow tubular element into two portions of the cavity, one located upstream relative to the at least one first segment and the other located downstream relative to the at least one first segment. The at least one first segment forming the first section of the downstream section may form the first empty portion, and the two portions of the cavity formed on each side of the at least one first segment may form the second section of the downstream section and may form the second empty portion. One of the portions of the cavity, which is located furthest downstream, may form a cavity in the form of a recess, extending from the end located downstream of the at least one first segment to the mouthpiece end of the aerosol generating article, and one of the portions of the cavity, which is located upstream, may form a cavity between the end located upstream of the at least one first segment (or first section) and the end located downstream of the aerosol generating element (which is also considered to be the end located upstream of the section located downstream).

The first segment may be located near the mouth end of the aerosol-generating article. The first segment may extend toward the mouth end of the aerosol-generating article. The first segment may extend from the downstream end of the second section, which may comprise a hollow tubular element, to the mouth end of the aerosol-generating article. Alternatively, the first segment may be located upstream relative to the mouth end of the aerosol-generating article. Preferably, the first segment may be located downstream relative to any ventilation zones or ventilation lines provided in the downstream section. Preferably, the first segment is located in the downstream half of the downstream section. The downstream half of the downstream section refers to the portion of the downstream section that extends from the middle or center of the downstream section to the mouth end or the downstream end of the downstream section. Thus, the length of the downstream half of the downstream section may be equal to 50 percent of the length of the downstream section. Preferably, the first segment may be positioned between the ventilation zone or line (or the ventilation zone or line located furthest downstream) and the mouthpiece end of the product.

Providing the first segment of the first section at or near the mouth end of the aerosol-generating article provides structural rigidity and integrity in a downstream portion of the downstream section, the majority of which may comprise at least one hollow tubular element that forms a cavity (or a second void), while also allowing a certain amount of air to pass through it by ensuring that the first void maintains a relatively low RTD of the aerosol-generating article and by providing a physical barrier that prevents any displaced portions of the aerosol-generating element from escaping from the aerosol-generating article through the mouth end.

The upstream end of the first segment of the first section may be located at a distance of approximately 18 mm or less downstream from the downstream end of the downstream section. The upstream end of the first segment of the first section may be located at a distance of approximately 15 mm or less downstream from the downstream end of the downstream section. The upstream end of the first segment of the first section may be located at a distance of approximately 12 mm or less downstream from the downstream end of the downstream section. The upstream end of the first segment of the first section may be located at a distance of at least approximately 0 mm downstream from the zone or ventilation line that is located furthest downstream. The upstream end of the first segment of the first section may be located at a distance of at least approximately 1 mm downstream from the zone or ventilation line that is located furthest downstream. The upstream end of the first segment of the first section may be positioned at least approximately 2 mm downstream of the zone or ventilation line that is located furthest downstream.

Alternatively, the first segment may be located upstream of any ventilation zones or ventilation lines provided in the downstream section. The first segment may be located in the upstream half of the downstream section. The upstream half of the downstream section refers to the portion of the downstream section that extends from the middle or center of the downstream section to the upstream end of the downstream section. Thus, the length of the upstream half of the downstream section may be equal to 50 percent of the length of the downstream section. The first segment may be located in a position between the ventilation zone or line (or the upstream zone or ventilation line) and the downstream end of the aerosol generating element.

The diameter of the first segment (or first section) may be substantially the same as the outer diameter of the hollow tubular element. As mentioned in this description, the outer diameter of the hollow tubular element may be approximately 7.3 mm.

The diameter of the first segment may be from approximately 5 mm to approximately 10 mm. The diameter of the first segment may be from approximately 6 mm to approximately 8 mm. The diameter of the first segment may be from approximately 7 mm to approximately 8 mm. The diameter of the first segment may be approximately 7.3 mm.

Alternatively, the diameter of the first segment (or first section) may be substantially the same as the inner diameter of at least one hollow tubular element of the second section. In other words, the diameter of the first section may be the same as the inner diameter of the second section. As mentioned in this description of the invention, the inner diameter of the hollow tubular element may be 7.1 mm. The diameter of the first segment may be approximately 7.1 mm. The first segment may instead be located within the hollow tubular element of the second section located downstream of the section. The first segment may therefore be surrounded by a wall of the hollow tubular element, preferably impermeable to air, such that air cannot pass between the inner surface of the hollow tubular element and the first segment and can only pass through the first segment.

Alternatively, from about 5 to about 30 percent of the length of the downstream section may comprise a first section that forms a first empty portion for air to pass through, and at least about 70 percent of the length of the downstream section may comprise a second section that forms a second empty portion for air to pass through. More preferably, from about 5 to about 25 percent of the length of the downstream section may comprise a first section that forms a first empty portion for air to pass through, and at least about 75 percent of the length of the downstream section may comprise a second section that forms a second empty portion for air to pass through. Even more preferably, from about 5 to about 20 percent of the length of the downstream section may comprise a first section that forms a first empty portion for air to pass through, and at least about 80 percent of the length of the downstream section may comprise a second section that forms a second empty portion for air to pass through. Alternatively, from about 5 to about 15 percent of the length of the downstream section may comprise a first section that forms a first void for air passage, and at least about 85 percent of the length of the downstream section may comprise a second section that forms a second void for air passage. Preferably, from about 5 to about 10 percent of the length of the downstream section may comprise a first section that forms a first void for air passage, and at least about 90 percent of the length of the downstream section may comprise a second section that forms a second void for air passage.

Unless otherwise specified, the resistance to draw (RTD) of an aerosol-generating component or article is measured in accordance with ISO 6565-2015. RTD refers to the pressure required to force air through the entire length of the component. The terms "pressure drop" or "resistance to draw" of a component or article may also refer to "resistance to draw." Such terms generally refer to measurements in accordance with ISO 6565-2015, which are typically performed under test conditions at a volumetric flow rate of approximately 17.5 milliliters per second at the outlet or downstream end of the component being measured, a temperature of approximately 22 degrees Celsius, a pressure of approximately 101 kPa (approximately 760 Torr), and a relative humidity of approximately 60%.

The resistance to draw per unit length of a specific component (or element) of an aerosol-generating article, such as a downstream section, a first section, or a first segment, can be calculated by dividing the measured resistance to draw of the component by the overall axial length of the component. The RTD per unit length refers to the pressure required to force air through a unit length of the component. Throughout this specification, a unit length refers to a length of 1 mm. Accordingly, to obtain the RTD per unit length of a specific component, a sample of a specific length, for example, 15 mm, of the component can be used in the measurement. The RTD of such a sample is measured in accordance with ISO 6565-2015. If, for example, the measured RTD is approximately 15 mm H2O, then the RTD per unit length of the component is approximately 1 mm H2O per mm. The RTD per unit length of the component depends on the structural properties of the material used for the component, as well as the geometric shape or cross-sectional profile of the component, among other factors.

The relative RTD, or RTD per unit length, of the downstream section may range from approximately 0 mm H2O per mm to approximately 3 mm H2O per mm. The RTD per unit length of the downstream section may range from approximately 0 mm H2O per mm to approximately 0.75 mm H2O per mm.

As mentioned above, the relative RTD, or RTD per unit length, of the downstream section may be greater than approximately 0 mm H2O per mm and less than approximately 3 mm H2O per mm. The RTD per unit length of the downstream section may be greater than approximately 0 mm H2O per mm and less than approximately 0.75 mm H2O per mm.

The RTD per unit length of the downstream section may be greater than or equal to approximately 0 mm H2O per mm. Thus, the RTD per unit length of the downstream section may be from approximately 0 mm H2O per mm to approximately 3 mm H2O per mm. The RTD per unit length of the downstream section may be from approximately 0 mm H2O per mm to approximately 0.75 mm H2O per mm.

The draw resistance of the downstream section may be greater than or equal to approximately 0 mm H2O and less than approximately 10 mm H2O. The draw resistance of the downstream section may be greater than 0 mm H2O and less than approximately 1 mm H2O.

The resistance to draw (RTD) characteristics of a downstream section may be completely or largely related to the RTD characteristics of the first section of the downstream section. In other words, the RTD of the first section of the downstream section may completely determine the RTD of the downstream section.

The relative RTD, or RTD per unit length, of the first section (or at least the first segment forming the first section) may be from about 0 mm H2O per mm to about 3 mm H2O per mm. The RTD per unit length of the first section may be from about 0 mm H2O per mm to about 0.75 mm H2O per mm.

As mentioned above, the relative RTD, or RTD per unit length, of the first section may be greater than approximately 0 mm H2O per mm and less than approximately 3 mm H2O per mm. The RTD per unit length of the first section may be greater than approximately 0 mm H2O per mm and less than approximately 0.75 mm H2O per mm.

The RTD per unit length of the first section may be greater than or equal to approximately 0 mm H2O per mm. Thus, the RTD per unit length of the first section may be from approximately 0 mm H2O per mm to approximately 3 mm H2O per mm. The RTD per unit length of the first section may be from approximately 0 mm H2O per mm to approximately 0.75 mm H2O per mm.

The tightening resistance of the first section (or the first segment forming the first section) may be greater than or equal to approximately 0 mm H2O and less than approximately 10 mm H2O. The tightening resistance of the first section may be greater than 0 mm H2O and less than approximately 1 mm H2O.

The first segment may comprise at least one segment airflow channel extending along the first segment. The segment airflow channel may also be referred to as the segment airflow channel throughout this specification. Providing at least one segment airflow channel in the first segment allows the downstream section to provide a relatively low RTD by allowing air to pass through it, while simultaneously ensuring that the first segment provides a physical barrier to prevent the inadvertent release of the aerosol-generating element material from the mouthpiece end of the aerosol-generating article. As mentioned in this specification, the aerosol-generating element material may comprise cut vegetable filler, in particular cut tobacco filler.

The ratio of the total cross-sectional area of at least one channel of the segment to the total cross-sectional area of the first segment (or first section) of the downstream section may be at least approximately 5%. In other words, the open area or first void portion formed by the first segment may have a total cross-sectional area that is at least approximately 5% of the total cross-sectional area of the first segment. The total cross-sectional area of the first segment, the first section, the second section, the downstream section, the aerosol-generating element, or the aerosol-generating article may be the same as the cross-sectional area calculated on the basis of the respective outer diameters of the first segment, the first section, the second section, the downstream section, the aerosol-generating element, or the aerosol-generating article. The total cross-sectional area of a component in the present invention refers to the total area within the outer perimeter (cross-section) of such component. For example, the total cross-sectional area of a cylindrical component may be equal to the circular cross-sectional area calculated based on the outer diameter of the cylindrical component, i.e., the area occupied by the cross-section of the component. As another example, in the present invention, the total cross-sectional area of a hollow tubular element may be equal to the circular cross-sectional area calculated based on the outer diameter of the hollow tubular element. The total cross-sectional area of the first void portion may be the same as the sum of the cross-sectional areas of each of at least one channel segment formed by the first segment of the first section located downstream of the section.

The ratio of the total cross-sectional area of at least one channel of the segment (the first segment) to the total cross-sectional area of the first segment (or section) may be at least approximately 10%. The ratio of the total cross-sectional area of at least one channel of the segment (the first segment) to the total cross-sectional area of the first segment (or section) may be at least approximately 30%. The ratio of the total cross-sectional area of at least one channel of the segment (the first segment) to the total cross-sectional area of the first segment (or section) may be at least approximately 40%. The ratio of the total cross-sectional area of at least one channel of the segment to the total cross-sectional area of the first segment may be at least approximately 65%. The ratio of the total cross-sectional area of at least one channel of the segment to the total cross-sectional area of the first segment may be at least approximately 70%. Additionally, the first segment itself may be porous. Providing a large proportion of the segment channels, or open area, void space, or empty section ensures that the RTD and RTD per unit length of the first segment and the downstream section are advantageously low, while ensuring that there is sufficient first segment material to prevent any portions of the aerosol generating element from escaping from the article.

The ratio of the total cross-sectional area of at least one channel of the segment to the total cross-sectional area of the first segment may be at most approximately 95%. The ratio of the total cross-sectional area of at least one channel of the segment to the total cross-sectional area of the first segment may be at most approximately 85%. The ratio of the total cross-sectional area of at least one channel of the segment to the total cross-sectional area of the first segment may be at most approximately 75%.

The ratio of the total cross-sectional area of the second empty portion to the total cross-sectional area of the second section of the downstream section may be at least approximately 25%. In other words, the open area formed by the second empty portion of the downstream section may be at least approximately 25% of the total cross-sectional area of the second section of the downstream section, which may have a uniform cross-sectional area. Preferably, the total cross-sectional area of the first section of the downstream section is the same as the total cross-sectional area of the second section of the downstream section. Accordingly, the cross-sectional area of the downstream section may be substantially uniform.

The ratio of the total cross-sectional area of the second void to the total cross-sectional area of the downstream section may be at least approximately 50%. The ratio of the total cross-sectional area of the second void to the total cross-sectional area of the downstream section may be at least approximately 75%. The ratio of the total cross-sectional area of the second void to the total cross-sectional area of the downstream section may be at least approximately 80%. Providing a large proportion of open area or void ensures that the RTD and RTD per unit length of the downstream section and the aerosol-generating article as a whole are advantageously low.

The ratio of the total cross-sectional area of the second empty portion to the total cross-sectional area of the second section may be at most approximately 99%. The ratio of the total cross-sectional area of the second empty portion to the total cross-sectional area of the second section may be at most approximately 95%. The ratio of the total cross-sectional area of the second empty portion to the total cross-sectional area of the second section may be at most approximately 90%.

The ratio of the total cross-sectional area of the second empty portion to the total cross-sectional area of the first empty portion, which can be formed by at least one air flow channel of the segment, can be more than about 1.1 (110%), preferably more than about 1.3 (130%), more preferably about 1.5 (150%) and even more preferably about 2 (200%).

The inner diameter or width of at least one air flow channel of the segment may be from approximately 1 mm to approximately 6 mm. The inner diameter or width of at least one air flow channel of the segment may be from approximately 2 mm to approximately 5 mm. The inner diameter or width of at least one air flow channel of the segment may be from approximately 3 mm to approximately 4 mm.

The internal diameter or width of at least one airflow channel of the segment (which forms the first void) may be smaller than the internal diameter of the airflow channel provided by at least one cavity of the second void. As discussed above, at least one cavity may be formed by at least one hollow tubular element in accordance with the present invention. The hollow tubular element forming the second void may therefore have the same characteristics, such as geometric shape, as the hollow tubular element defined in the present invention.

The first segment may be formed from a fibrous material. The first segment may be formed from a porous material. The first segment may be formed from a biodegradable material. The first segment may be formed from a cellulosic material, such as cellulose acetate. For example, the first segment may be formed from a bundle of cellulose acetate fibers having a denier per fiber of approximately 10 to approximately 15. For example, the first segment is formed from a relatively low-density cellulose acetate tow, such as a cellulose acetate tow containing fibers of approximately 12 denier per fiber, which can provide an RTD per unit length of approximately 0.8 to approximately 2.5 mm H2O per mm.

The first segment can be formed from a polylactic acid-based material. The first segment can be formed from a bioplastic material, preferably a starch-based bioplastic material. The first segment can be manufactured by injection molding or extrusion. Bioplastic-based materials are advantageous because they can provide first segment structures that are simple and inexpensive to manufacture with a specific and complex cross-sectional profile. These structures can contain multiple, relatively large airflow channels through the first segment material, ensuring suitable RTD characteristics.

The first segment may be formed from a sheet of suitable material, corrugated, pleated, gathered, woven, or folded into an element that forms multiple channels extending longitudinally. Such a sheet of suitable material may be formed from paper, cardboard, a polymer such as polylactic acid, or any other cellulose-based material, paper-based material, or bioplastic-based material. A cross-sectional profile of such a first segment may show the channels as randomly oriented.

The first segment may be formed by any other suitable method. For example, the first segment may be formed from a bundle of longitudinally extending tubes. The longitudinal tubes may be formed from polylactic acid. The first segment may be formed by extrusion, casting, lamination, injection, or milling of a suitable material. Thus, it is preferable to have a small pressure drop (or RTD) from the upstream end of the first segment to the downstream end of the first segment.

The first segment may not consist of a hollow tubular element, as defined in the present invention, that forms a single unobstructed airflow channel between its upstream and downstream ends. Such a hollow tubular element would effectively provide an RTD, and an RTD per unit length, of 0 mm H2O.

The length of the first segment may be at least approximately 1 mm. The length of the first segment may not be greater than approximately 15 mm. The length of the first segment may be from approximately 1 mm to approximately 15 mm. The length of the first segment may be from approximately 5 millimeters to approximately 15 millimeters. Preferably, the length of the first segment may be from approximately 1 mm to approximately 10 mm. The length of the first segment may be approximately 6 mm. Preferably, the length of the first section (or the first segment of the first section) is less than the length of the second section of the downstream section, which may be formed by at least one hollow tubular element, so that the relatively low RTD characteristics of the downstream section are not affected by the relatively long first segment, which has a higher RTD than that of the second section or part of the downstream section.

The upstream end of the aerosol-generating article may be formed by a wrapper. Providing a wrapper at the upstream end of the aerosol-generating article may advantageously retain the aerosol-generating substrate within the aerosol-generating article. This feature may also advantageously prevent users from coming into direct contact with the aerosol-generating substrate.

The wrapper can be mechanically sealed at the upstream end of the aerosol-generating product. This can be achieved by folding or twisting the wrapper. Adhesive can be used to seal the upstream end of the aerosol-generating product.

The wrapper forming the upstream end of the aerosol generating article may be formed from the same piece of material as the wrapper surrounding at least a portion of the downstream section.

Ensuring this can advantageously facilitate the manufacture of the aerosol-generating article, as only a single piece of wrapper material may be required. Furthermore, using a single piece of wrapper material can eliminate the need for a seam to join two pieces of wrapper material. This can advantageously simplify manufacture. The absence of a seam can also advantageously prevent or reduce leakage of any aerosol-generating substrate from the aerosol-generating article.

The aerosol-generating article according to the present invention may further comprise an upstream section. The upstream section may comprise an upstream element located upstream of the aerosol-generating substrate. The upstream element may extend from the upstream end of the aerosol-generating substrate to the upstream end of the aerosol-generating article. The upstream element may abut the upstream end of the aerosol-generating article.

An aerosol-generating article may comprise an air inlet at the upstream end of the aerosol-generating article. If the aerosol-generating article comprises an upstream section, the air inlet may be provided through the upstream element. Air entering through the air inlet may pass into the aerosol-generating substrate to generate the mainstream aerosol.

An upstream section may have a high RTD.

In embodiments of the present invention, if the downstream section has a relatively low RTD, for example, an RTD of less than about 10 mm H2O, the provision of an upstream element having a relatively high RTD can advantageously provide an acceptable overall RTD without the need for a high RTD element, such as a filter, downstream of the aerosol-generating substrate. In use, air enters the aerosol-generating article through the upstream end of the upstream section, passes through the upstream section, and into the aerosol-generating substrate. The air then passes into and through the downstream section, and then exits from the downstream end of the downstream section.

Most of the total RTD of an aerosol generating product can be provided by the RTD of an upstream section.

The ratio of the RTD of the upstream section to the RTD of the downstream section may be greater than 1. For example, the ratio of the RTD of the upstream section to the RTD of the downstream section may be greater than about 2, greater than about 5, greater than about 8, greater than about 10, greater than about 15, greater than about 20, or greater than about 50.

The RTD of the upstream section may be at least about 5 mm H2O. For example, the RTD of the upstream section may be at least about 10 mm H2O, at least about 12 mm H2O, at least about 15 mm H2O, at least about 20 mm H2O.

The RTD of the upstream section may be no more than approximately 80 mm H2O. For example, the RTD of the upstream section may be no more than approximately 70 mm H2O, no more than approximately 60 mm H2O, no more than approximately 50 mm H2O, or no more than approximately 40 mm H2O.

The RTD of the upstream section may be from about 5 mmH2O to about 80 mmH2O. For example, the RTD of the upstream section may be from about 10 mmH2O to about 70 mmH2O, from about 12 mmH2O to about 60 mmH2O, from about 15 mmH2O to about 50 mmH2O, or from about 20 mmH2O to about 40 mmH2O.

An upstream section can advantageously prevent direct physical contact with the upstream end of the aerosol-generating substrate. In particular, when the aerosol-generating substrate contains a susceptor element, the upstream section can prevent direct physical contact with the upstream end of the susceptor element. This helps prevent displacement or deformation of the susceptor element during handling or transport of the aerosol-generating article. This, in turn, helps maintain the shape and position of the susceptor element. Furthermore, the presence of an upstream section can help prevent any loss of substrate, which may be advantageous, for example, if the substrate contains particulate plant material.

The upstream section may also provide an improved appearance to the upstream end of the aerosol-generating article. Furthermore, if desired, the upstream section may be used to provide information about the aerosol-generating article, such as brand, flavor, content, or information about the aerosol-generating device with which the article is intended.

If the upstream section comprises an upstream element, the upstream element may comprise a porous plug element. The porous plug element may have a porosity of at least approximately 50 percent in the longitudinal direction of the aerosol-generating article. More preferably, the porous plug element has a porosity of from approximately 50 percent to approximately 90 percent in the longitudinal direction. The porosity of the porous plug element in the longitudinal direction is determined by the ratio of the cross-sectional area of the material forming the porous plug element to the internal cross-sectional area of the aerosol-generating article at the position of the porous plug element.

The porous plug-shaped element may be made of a porous material or may contain multiple holes. This can be achieved, for example, by laser perforation. Preferably, the multiple holes are evenly distributed across the cross-section of the porous plug-shaped element.

The porosity or permeability of the upstream element can advantageously be varied to provide a desired overall draw resistance of the aerosol generating article.

In alternative embodiments, the upstream element may be formed from an air-impermeable material. In such embodiments, the aerosol-generating article may be designed such that air flows into the aerosol-generating substrate rod through suitable ventilation means provided in the wrapper.

The upstream element may be made of any material suitable for use in an aerosol-generating article. For example, the upstream element may comprise a plug made of the material. Suitable materials for forming the upstream element include filter materials, ceramics, polymeric material, cellulose acetate, cardboard, zeolite, or an aerosol-generating substrate. Preferably, the upstream element comprises a plug comprising cellulose acetate.

If the upstream element contains a material plug, the downstream end of the material plug may abut the upstream end of the aerosol-generating substrate. For example, the upstream element may contain a plug containing cellulose acetate that abuts the upstream end of the aerosol-generating substrate. This may advantageously help hold the aerosol-generating substrate in place.

If the upstream element contains a material plug, the downstream end of the material plug may be spaced apart from the upstream end of the aerosol-generating substrate. The upstream element may contain a plug containing fibrous filter material.

Preferably, the upstream element is made of a heat-resistant material. For example, the upstream element is preferably made of a material that can withstand temperatures up to 350 degrees Celsius. This ensures that the upstream element is not adversely affected by the heating means used to heat the aerosol-generating substrate.

Preferably, the upstream section has a diameter that is approximately equal to the diameter of the aerosol generating article.

The upstream section may have a length of at least approximately 1 millimeter. For example, the upstream section may have a length of at least approximately 2 millimeters, at least approximately 4 millimeters, or at least approximately 6 millimeters.

The upstream section may be no more than approximately 15 millimeters long. For example, the upstream section may be no more than approximately 12 millimeters long, no more than approximately 10 millimeters long, or no more than approximately 8 millimeters long.

The upstream section may have a length of between approximately 1 millimeter and approximately 15 millimeters. For example, the upstream section may have a length of between approximately 2 millimeters and approximately 12 millimeters, between approximately 4 millimeters and approximately 10 millimeters, or between approximately 6 millimeters and approximately 8 millimeters.

The length of the upstream section can be advantageously varied to achieve the desired overall length of 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 section can be increased to maintain the same overall article length.

The upstream section preferably has a substantially uniform structure. For example, the upstream section may be substantially uniform in texture and appearance. The upstream section may, for example, have a continuous, regular surface across its entire cross-section. The upstream section may, for example, have no recognizable symmetries.

The upstream section may comprise a second tubular element. The second tubular element may be provided in place of the upstream element. The second tubular element may be provided immediately upstream of the aerosol-generating substrate. The second tubular element may abut the aerosol-generating substrate.

The second tubular element may comprise a tubular main portion defining a cavity extending from a first upstream end of the tubular main portion to a second downstream end of the tubular main portion. The second tubular element may also comprise a bent end portion defining a first end wall at the first upstream end of the tubular main portion. The first end wall may define an opening that permits airflow between the cavity and the exterior of the second tubular element. Preferably, air may flow from the cavity through the opening and into the aerosol-generating substrate.

The second tubular element may comprise a second end wall at the second end of its tubular base portion. This second end wall may be formed by bending the end portion of the second tubular element at a second downstream end of the tubular base portion. The second end wall may define an opening that may also permit airflow between the cavity and the exterior of the second tubular element. In the case of the second end wall, the opening may be configured such that air can pass from outside the aerosol-generating article through the opening and into the cavity. The opening may therefore provide a channel through which air can be drawn into the aerosol-generating article and through the aerosol-generating substrate.

The upstream element or the second tubular element is preferably surrounded by a wrapper. The wrapper surrounding the upstream element or the second tubular element is preferably a rigid filament, such as a filament having a basis weight of at least about 80 grams per square meter (g/m2), or at least about 100 g/m2, or at least about 110 g/m2. This provides structural rigidity to the upstream element.

As discussed above, the present invention also relates to an aerosol-generating system comprising an aerosol-generating device having a distal end and a mouthpiece end. The aerosol-generating device comprises a main portion. The main portion of the aerosol-generating device defines a cavity for removably positioning an aerosol-generating article at the mouthpiece end of the device. The aerosol-generating device comprises a heating element or heater for heating an aerosol-generating substrate when the aerosol-generating article is positioned within the cavity of the device.

The cavity of the device may be referred to as the heating chamber of the aerosol-generating device. The cavity may extend between the distal end and the mouthpiece, or near end. The distal end of the cavity may be the closed end, and the mouthpiece, or near end, of the cavity may be the open end. The aerosol-generating article can be inserted into the cavity of the device, or heating chamber, through the open end of the cavity. The cavity of the device may be cylindrical in shape to match the shape of the aerosol-generating article.

The term "housed within" may refer to the fact that a component or element is fully or partially housed within another component or element. For example, the term "an aerosol-generating article housed within a cavity of a device" refers to an aerosol-generating article that is fully or partially housed within the cavity of the device of the aerosol-generating article. When an aerosol-generating article is housed within a cavity of a device, the aerosol-generating article may abut the distal end of the cavity of the device. When an aerosol-generating article is housed within a cavity of a device, the aerosol-generating article may be in substantial proximity to the distal end of the cavity of the device. The distal end of the cavity of the device may be defined by an end wall.

An aerosol-generating device may include an elongated heater (or heating element) designed to be inserted into the aerosol-generating article when the aerosol-generating article is positioned within the cavity of the device. The elongated heater may be arranged within the cavity of the device. The elongated heater may extend into the cavity of the device. Alternative heating arrangements are discussed in more detail below.

The heater may be any suitable type of heater.

Preferably, the heater can externally heat the aerosol-generating article when it is placed within the aerosol-generating device. Such an external heater can surround the aerosol-generating article when it is inserted into or positioned within the aerosol-generating device.

In some embodiments, the heater is positioned to heat the outer surface of the aerosol-forming substrate. In some embodiments, the heater is adapted to be inserted into the aerosol-forming substrate when the aerosol-forming substrate is positioned within the cavity. The heater may be positioned within the cavity of the device, or a heating chamber.

The heater may comprise at least one heating element. The at least one heating element may be a heating element of any suitable type. In some embodiments, the device comprises only one heating element. In some embodiments, the device comprises multiple heating elements. The heater may comprise at least one resistive heating element. Preferably, the heater comprises multiple resistive heating elements. Preferably, the resistive heating elements are electrically connected in a parallel arrangement. Advantageously, providing multiple resistive heating elements electrically connected in a parallel arrangement can facilitate the delivery of the desired electrical power to the heater, while reducing or minimizing the voltage required to provide the desired electrical power. Advantageously, reducing or minimizing the voltage required to operate the heater can contribute to reducing or minimizing the physical size of the power supply.

In some embodiments, the heater comprises an induction heating device. The induction heating device may comprise an induction coil and a power supply configured to supply a high-frequency oscillating current to the induction coil. In the context of this document, "high-frequency oscillating current" means an oscillating current with a frequency of 500 kHz to 30 MHz. The heater may advantageously comprise a DC-to-AC converter for converting the DC current supplied by the DC power supply into an AC current. The induction coil may be designed to generate a high-frequency oscillating electromagnetic field upon receiving the high-frequency oscillating current from the power supply. The induction coil may be designed to generate a high-frequency oscillating electromagnetic field within the cavity of the device. In some embodiments, the induction coil may substantially surround the cavity of the device. The induction coil may extend at least partially along the length of the cavity of the device.

The heater may comprise an induction heating element. The induction heating element may be a susceptor element. As used herein, the term "susceptor element" refers to an element comprising a material capable of converting electromagnetic energy into heat. When the susceptor element is placed in an alternating electromagnetic field, the susceptor element heats up. Heating of the susceptor element may result from at least one of hysteresis losses and eddy currents induced in the susceptor, depending on the electrical and magnetic properties of the susceptor material.

The current-receiving element may be configured such that, when the aerosol-generating article is placed in the cavity of the aerosol-generating device, the oscillating electromagnetic field generated by the induction coil induces a current in the current-receiving element, which leads to heating of the current-receiving element. In these embodiments, the aerosol-generating device is preferably capable of generating a fluctuating electromagnetic field having a magnetic field strength (field strength H) of 1 to 5 kiloamperes per meter (kA/m), preferably 2 to 3 kA/m, for example approximately 2.5 kA/m. The electrical aerosol-generating device is preferably capable of generating a fluctuating electromagnetic field having a frequency of 1 to 30 MHz, for example 1 to 10 MHz, for example 5 to 7 MHz.

In some embodiments, the current-collecting element is located within an aerosol-generating article. In these embodiments, the current-collecting element is preferably positioned in contact with the aerosol-generating substrate. The current-collecting element may be positioned within the aerosol-generating substrate.

In some embodiments, the current-collecting element is located within the aerosol-generating device. In these embodiments, the current-collecting element may be located within a cavity. The aerosol-generating device may contain only one current-collecting element. The aerosol-generating device may contain multiple current-collecting elements.

In some embodiments, the current-collecting element is positioned to heat the outer surface of the aerosol-forming substrate. In some embodiments, the current-collecting element is adapted to be inserted into the aerosol-forming substrate when the aerosol-forming substrate is positioned within the cavity.

The current-collecting element may comprise any suitable material. The current-collecting element may be formed from any material that can be inductively heated to a temperature sufficient to release volatile compounds from the aerosol-forming substrate. Suitable materials for an elongated current-collecting element include graphite, molybdenum, silicon carbide, stainless steel, niobium, aluminum, nickel, nickel compounds, titanium, and metallic composites. Some current-collecting elements contain metal or carbon. Advantageously, the current-collecting element may comprise or consist of a ferromagnetic material, such as ferritic iron, a ferromagnetic alloy such as ferromagnetic steel or stainless steel, ferromagnetic particles, and ferrite. A suitable current-collecting element may be made of or comprise aluminum. The current collecting element preferably contains more than about 5 percent, preferably more than about 20 percent, more preferably more than about 50 percent, or more than about 90 percent ferromagnetic or paramagnetic materials. Some elongated current collecting elements can be heated to a temperature in excess of about 250 degrees Celsius.

The current-collecting element may comprise a non-metallic core with a metallic layer located on the non-metallic core. For example, the current-collecting element may comprise metallic tracks formed on the outer surface of a ceramic core or substrate.

In some embodiments, the aerosol-generating device may comprise at least one resistive heating element and at least one inductive heating element. In some embodiments, the aerosol-generating device may comprise a combination of resistive heating elements and inductive heating elements.

During use, the heater can be controlled to operate within a specified operating temperature range below the maximum operating temperature. A preferred operating temperature range is from approximately 150 degrees Celsius to approximately 250 degrees Celsius in the heating chamber (or cavity of the device). The heater's operating temperature range can be from approximately 150 degrees Celsius to approximately 250 degrees Celsius. The heater's operating temperature range can be from approximately 180 degrees Celsius to approximately 200 degrees Celsius.

In embodiments where the aerosol generating article comprises a ventilation zone at a location along a downstream section or hollow tubular member, the ventilation zone may be positioned to be open when the aerosol generating article is positioned within the cavity of the device.

The aerosol-generating device may include a power supply. The power supply may be a DC power supply. In some embodiments, the power supply is a battery.

The aerosol generating article may have a length ranging from approximately 35 millimeters to approximately 100 millimeters.

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

The overall length of the aerosol-generating article according to the present invention is preferably less than or equal to 70 millimeters. More preferably, the overall length of the aerosol-generating article according to the present invention is preferably less than or equal to 60 millimeters. Even more preferably, the overall length of the aerosol-generating article according to the present invention is preferably less than or equal to 50 millimeters.

In some embodiments, the overall length of the aerosol-generating article is preferably from about 38 millimeters to about 70 millimeters, more preferably from about 40 millimeters to about 70 millimeters, even more preferably from about 42 millimeters to about 70 millimeters. In other embodiments, the overall length of the aerosol-generating article is preferably from about 38 millimeters to about 60 millimeters, more preferably from about 40 millimeters to about 60 millimeters, even more preferably from about 42 millimeters to about 60 millimeters. In further embodiments, the overall length of the aerosol-generating article is preferably from about 38 millimeters to about 50 millimeters, more preferably from about 40 millimeters to about 50 millimeters, even more preferably from about 42 millimeters to about 50 millimeters. In an exemplary embodiment, the overall length of the aerosol generating article is approximately 45 millimeters.

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.

Preferably, the aerosol-generating article has an outer diameter of less than or equal to approximately 12 millimeters. More preferably, the aerosol-generating article has an outer diameter of less than or equal to approximately 10 millimeters. Even more preferably, the aerosol-generating article has an outer diameter of less than or equal to approximately 8 millimeters.

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

The aerosol generating product can have a length from 3.7 millimeters to 9 millimeters, or from 5.7 millimeters to 7.9 millimeters.

One or more components of the aerosol-generating article may be individually enclosed in a wrapper. In preferred embodiments, all components of the aerosol-generating article are individually enclosed in their own wrapper. Preferably, at least one component of the aerosol-generating article is enclosed in a hydrophobic wrapper.

The term "hydrophobic" refers to a surface that exhibits water-repellent properties. One common method for determining this property is by measuring the water contact angle. The water contact angle is the angle, typically measured using a liquid, where the liquid/vapor interface meets a solid surface. It quantitatively expresses the wettability of the solid surface by the liquid according to Young's equation. Hydrophobicity, or the water contact angle, can be determined using TAPPI Test Method T558, and the result is reported as the contact angle at the interface, expressed in degrees, which can range from approximately zero to approximately 180 degrees.

In preferred embodiments, the hydrophobic wrapper is a wrapper comprising a paper layer having a water contact angle of about 30 degrees or greater, and preferably about 35 degrees or greater, or about 40 degrees or greater, or about 45 degrees or greater.

For example, the paper layer may contain PVOH (polyvinyl alcohol) or silicon. PVOH may be applied to the paper layer as a surface coating, or the paper layer may be surface treated with PVOH or silicon.

In a particularly preferred embodiment, the aerosol generating article according to the present invention comprises, in a linear sequential arrangement, an aerosol generating element comprising a rod comprising an aerosol generating substrate and a hollow tubular element positioned immediately downstream of the aerosol generating element.

In more detail, the hollow tubular element may abut against the aerosol generating element.

The aerosol generating article has a substantially cylindrical shape and an outer diameter of approximately 7.3 millimeters.

The hollow tubular element is shaped like a hollow cellulose acetate tube and has an internal diameter of approximately 7.1 millimeters. Therefore, the thickness of the peripheral wall of the hollow tubular element is approximately 0.1 millimeters. The ventilation zone is located along the hollow tubular element.

The aerosol generating element has the form of a rod of aerosol generating substrate surrounded by a paper wrapper and contains at least one of the types of aerosol generating substrate described above, such as a cut vegetable filler, and in particular a cut tobacco filler, homogenized tobacco, a gel composition or a homogenized vegetable material containing particles of a plant other than tobacco.

An outer rim wrapper surrounds the hollow tubular member and a portion of the aerosol generating member such that the hollow tubular member is secured to the aerosol generating member.

The aerosol-generating substrate rod is approximately 12 millimeters long, and the hollow tubular element is approximately 33 millimeters or approximately 29 millimeters long. Therefore, the total length of the aerosol-generating article is approximately 45 millimeters or approximately 41 millimeters.

In another preferred embodiment, an aerosol generating article according to the present invention comprises, in a linear sequential arrangement, an upstream element, an aerosol generating element positioned immediately downstream of the upstream element, an aerosol generating element comprising a rod comprising an aerosol generating substrate, and a hollow tubular element positioned immediately downstream of the aerosol generating element.

In more detail, the rod of the aerosol-generating substrate may rest against an element located upstream. Additionally, a hollow tubular element may rest against the aerosol-generating element.

The aerosol generating article has a substantially cylindrical shape and an outer diameter of approximately 7.3 millimeters.

The hollow tubular element is shaped like a hollow cellulose acetate tube and has an internal diameter of approximately 7.1 millimeters. Therefore, the thickness of the peripheral wall of the hollow tubular element is approximately 0.1 millimeters. The ventilation zone is located along the hollow tubular element.

The aerosol generating element has the form of a rod of aerosol generating substrate surrounded by a paper wrapper and contains at least one of the types of aerosol generating substrate described above, such as a cut vegetable filler, and in particular a cut tobacco filler, homogenized tobacco, a gel composition or a homogenized vegetable material containing particles of a plant other than tobacco.

An outer rim wrapper surrounds the hollow tubular member and a portion of the aerosol generating member such that the hollow tubular member is secured to the aerosol generating member.

The upstream element is 5 millimeters long, the aerosol-generating substrate rod is approximately 12 millimeters long, and the hollow tubular element is approximately 28 millimeters long. Thus, the total length of the aerosol-generating device is approximately 45 millimeters.

The present invention is defined in the claims. However, a non-exhaustive list of non-limiting examples is provided below. Any one or more features of these examples may be combined with any one or more features of another example, embodiment, or aspect described herein.

Example 1. An aerosol-generating article containing:

aerosol generating substrate,

a downstream section extending from the downstream end of the aerosol generating substrate to the downstream end of the aerosol generating article, wherein

the downstream section comprises a first ventilation zone for providing ventilation to the downstream section,

a first ventilation zone extending from the downstream end to the upstream end, wherein the upstream end is located at a distance of less than 5 millimeters from the downstream end of the aerosol generating substrate,

In this case, the tightening resistance of the section located further downstream is less than 10 mm H2O.

Example 2. An aerosol generating article according to example 1, wherein the first ventilation zone comprises a porous portion of a downstream section with ventilation of at least 20 percent.

Example 3. An aerosol generating article according to example 1 or example 2, further comprising a wrapper surrounding at least a portion of the downstream section, wherein the first ventilation zone comprises a porous portion of the wrapper.

Example 4. An aerosol generating article according to example 3, wherein the wrapper is a paper wrapper and the first ventilation zone comprises a portion of porous paper.

Example 5. An aerosol-generating article according to example 3 or example 4, wherein the porous portion of the wrapper that forms the first ventilation zone has a basis weight that is less than that of the portion of the wrapper that does not form part of the first ventilation zone.

Example 6. An aerosol-generating article according to any of examples 3-5, wherein the porous portion of the wrapper that forms the first ventilation zone has a thickness that is less than that of the portion of the wrapper that does not form part of the first ventilation zone.

Example 7. An aerosol-generating article according to any preceding example, wherein the downstream end of the first ventilation zone is located at a distance of less than 3 millimeters from the downstream end of the aerosol-generating substrate.

Example 8. An aerosol generating article according to any preceding example, wherein the upstream end of the first ventilation zone is located at a distance of less than 1 millimeter from the downstream end of the aerosol generating substrate.

Example 9. An aerosol generating article according to any preceding example, wherein the first ventilation zone has a length of at least 2 millimeters.

Example 10. An aerosol-generating article according to any preceding example, wherein the downstream section comprises an unobstructed airflow path from the downstream end of the aerosol-generating substrate to the downstream end of the downstream section.

Example 11. An aerosol generating article according to example 10, wherein the unobstructed air flow path from the downstream end of the aerosol generating substrate to the downstream end of the downstream section has a minimum diameter of 3 millimeters.

Example 12. An aerosol generating article according to any preceding example, wherein the downstream section has a length of at least 15 millimetres.

Example 13. An aerosol generating article according to any preceding example, wherein the downstream end of the first ventilation zone is located at a distance of at least 10 millimeters from the downstream end of the aerosol generating article.

Example 14. An aerosol generating article according to any preceding example, wherein the upstream end of the first ventilation zone is located at a distance of less than 15 percent of the path along the length of the downstream section from the downstream end of the aerosol generating substrate.

Example 15. An aerosol generating article according to any preceding example, wherein the downstream section comprises a hollow tubular element.

Example 16. An aerosol generating article according to example 15, wherein the hollow tubular member is located at a distance from a downstream end of the aerosol generating substrate, and wherein the hollow tubular member is connected to the aerosol generating substrate by a portion of a porous paper wrapper.

Example 17. An aerosol generating article according to example 15 or example 16, wherein the hollow tubular element comprises an acetate cellulose tow.

Example 18. An aerosol-generating article according to any preceding example, wherein the upstream end of the aerosol-generating article is defined by a wrapper.

Example 19. An aerosol generating article according to example 18, wherein the wrapper forming the upstream end of the aerosol generating article is formed from the same piece of material as the wrapper surrounding at least a portion of the downstream section.

Example 20. An aerosol generating article according to any preceding example, further comprising an upstream element located upstream of the aerosol generating substrate.

Example 21. An aerosol generating article according to example 20, wherein the upstream element abuts against the upstream end of the aerosol generating substrate.

Example 22. An aerosol generating article according to example 20 or example 21, wherein the upstream element has an RTD of at least 20 millimeters of water.

Example 23. An aerosol generating article according to any of examples 20-22, wherein the upstream element comprises a plug containing fibrous filter material.

Example 24. An aerosol-generating article according to any preceding example, further comprising an air inlet at an upstream end of the aerosol-generating article.

Example 25. An aerosol generating system comprising: an aerosol generating device comprising a heater; and

an aerosol-generating article according to any preceding example.

The present invention will now be further described with reference to the accompanying drawings, in which:

Fig. 1 is a schematic side sectional view of an aerosol generating article according to an embodiment of the present invention; and

Fig. 2 is a schematic side sectional view of another aerosol generating article in accordance with another embodiment of the present invention;

Fig. 3 shows a schematic side sectional view of the embodiment of the aerosol generating article of Fig. 1; and

Fig. 4 shows a schematic side sectional view of a variant of the aerosol generating article shown in Fig. 1.

The aerosol-generating article 10 shown in Fig. 1 comprises a rod of aerosol-generating substrate 12 and a downstream section 14 at a location downstream of the rod 12 of the aerosol-generating substrate. Thus, the aerosol-generating article 10 extends from an upstream, or distal, end 16, which substantially coincides with the upstream end of the aerosol-generating substrate 12, to a downstream, or mouthpiece, end 18, which coincides with the downstream end of the downstream section 14.

The aerosol generating article 10 has an overall length of approximately 45 millimeters.

Aerosol-generating substrate 12 contains cut tobacco filler impregnated with approximately 12 percent by weight of an aerosol-forming substance, such as glycerin. The cut tobacco filler comprises 90 percent by weight of tobacco leaf lamellas. The cut width of the cut tobacco filler is approximately 0.7 millimeters. The rod of aerosol-generating substrate 12 contains approximately 130 milligrams of cut tobacco filler.

The downstream section 14 comprises a hollow tubular element 20 positioned downstream of the aerosol-generating substrate 12, wherein the hollow tubular element 20 is in longitudinal alignment with the aerosol-generating substrate 12. In the embodiment of Fig. 1, the upstream end of the hollow tubular element 20 abuts the downstream end of the rod 12 of the aerosol-generating substrate.

The hollow tubular element 20 forms the hollow section of the aerosol-generating article 10. The hollow tubular element does not substantially affect the overall RTD of the aerosol-generating article. More specifically, the RTD of the downstream section is approximately 0 mm H2O.

The hollow tubular element 20 is provided in the form of a hollow cylindrical tube made of cellulose acetate or of rigid paper, such as paper having a grammage of at least approximately 90 g/m2. The hollow tubular element 20 forms an internal cavity 22, which extends all the way from the upstream end 24 of the hollow tubular element to the downstream end 26 of the hollow tubular element 20. The internal cavity 22 is substantially empty, and therefore a substantially unimpeded flow of air through the internal cavity 22 is possible. The hollow tubular element 20 does not substantially affect the overall RTD of the aerosol-generating article 10.

The hollow tubular element 20 has a length of approximately 33 millimeters, an outer diameter (D _E ) of approximately 7.3 millimeters, and an inner diameter (D _I ) of approximately 7.1 millimeters. Thus, the thickness of the peripheral wall of the hollow tubular element 20 is approximately 0.1 millimeters.

The hollow tubular element 20 is located at a distance from the downstream end of the aerosol-generating substrate 12. The distance between the downstream end of the aerosol-generating substrate 12 and the upstream end of the hollow tubular element 20 is approximately 2 millimeters.

The hollow tubular element 20 is connected to the aerosol-generating substrate 12 by a porous paper wrapper 35. The porous paper wrapper 35 surrounds the hollow tubular element 20 and the downstream portion of the aerosol-generating substrate 12 along its entire length. The portion of the porous paper wrapper 35 that covers the gap between the downstream end of the aerosol-generating substrate 12 and the upstream end of the hollow tubular element 20 allows air to enter the downstream section 14 through the porous paper wrapper 35, thereby providing the first ventilation zone 30.

The end of the first ventilation zone 30 located upstream of the flow rests against the end of the aerosol-generating substrate 12 located downstream of the flow.

The ventilation level of the aerosol generating article 10 provided by the first ventilation zone is approximately 40 percent.

In the embodiment of Fig. 1, the aerosol generating article does not contain any additional component upstream of the aerosol generating substrate rod 12 or downstream of the hollow tubular element 20.

The aerosol-generating article 100 shown in Fig. 2 differs from the aerosol-generating article 10 described above only by the provision of an upstream section at a location upstream of the aerosol-generating element. Accordingly, the aerosol-generating article 100 will be described below only with respect to its differences from the aerosol-generating article 10.

The aerosol generating article 100 comprises an upstream section comprising only one upstream element 40 at a location upstream of the aerosol generating substrate 12. As such, the aerosol generating article 100 extends from a distal end 16 substantially coinciding with the upstream end of the upstream element 40 to a mouth end, or downstream end, 18 substantially coinciding with the downstream end of the downstream section 14.

The upstream section 40 comprises an upstream element 42 positioned immediately upstream of the aerosol-generating substrate rod 12, wherein the upstream element 42 is in longitudinal alignment with the rod 12. In the embodiment of Fig. 2, the downstream end of the upstream element 42 abuts the upstream end of the aerosol-generating substrate rod 12. The upstream element 42 is provided in the form of a cylindrical plug made of cellulose acetate surrounded by a rigid wrapper. The upstream element 42 has a length of approximately 5 millimeters. The RTD of the upstream element 42 is approximately 30 millimeters of water.

Fig. 3 shows an aerosol generating article 200, which is a variant of the aerosol generating article 10 described above. The aerosol generating article 200 is generally the same as the aerosol generating article 10 according to the embodiment of Fig. 1, except that the aerosol generating article 200 according to the variant of the first embodiment does not contain the cylindrical hollow tubular element 20, which is described above. Instead, the aerosol generating article 200 of the variant according to the first embodiment contains a modified tubular element 220, located downstream of the aerosol generating element 12.

The modified tubular element 220 comprises a tubular main portion 222 that forms a cavity 224 that extends from a first end of the tubular main portion 222 to a second end of the tubular main portion 222. The modified tubular element 220 also comprises a bent end portion that forms a first end wall 226 at the first end of the tubular main portion 222. The first end wall 226 defines the boundaries of an opening 228 that allows air flow between the cavity 224 and the outer portion of the modified tubular element 220. In particular, the embodiment of Fig. 3 is designed so that the aerosol can flow from the aerosol generating element 12 through the opening 228 into the cavity 224.

Much like the cavity 22 of the first embodiment shown in Fig. 1, the cavity 224 of the tubular body 222 is substantially empty, and therefore a substantially unimpeded air flow is made possible through the cavity 222. Therefore, the RTD of the modified tubular element 220 can be localized at a specific longitudinal position of the modified tubular element 220, namely at the first end wall 226, and can be controlled by means of a selected configuration of the first end wall 226 and its corresponding opening 228. In the embodiment of Fig. 3, the RTD of the modified tubular element 220 (which is essentially the RTD of the first end wall 226) is approximately 5 millimeters of water.

In the embodiment of Fig. 3, the modified tubular element 220 has a length of approximately 33 millimeters, an outer diameter (D _E ) of approximately 7.3 millimeters, and an inner diameter (D _FTS ) of approximately 7.1 millimeters. Thus, the thickness of the peripheral wall of the tubular main portion 222 is approximately 0.1 millimeter.

Fig. 4 shows an aerosol-generating article 300, which is a variant of the aerosol-generating article 100 described above. The aerosol-generating article 300 is generally the same as the aerosol-generating article 100 according to the embodiment of Fig. 2, except that the aerosol-generating article 300 according to the second embodiment does not contain an upstream element 42 provided in the form of a cylindrical plug made of cellulose acetate surrounded by a rigid wrapper. Instead, the aerosol-generating article 300 according to the second embodiment contains a second tubular element 44 located immediately upstream of the aerosol-generating element 12. Therefore, in this embodiment according to the second embodiment, the hollow tubular element 20 located immediately downstream of the aerosol generating element 12 may be referred to as the first tubular element 20.

The second tubular element 44 comprises a tubular main portion 46 that forms a cavity 48 that extends from the first end of the tubular main portion 46 to the second end of the tubular main portion 46. The second tubular element 44 also comprises a bent end portion that forms a first end wall 50 at the first end of the tubular main portion 46. The first end wall 50 defines the boundaries of an opening 52 that allows air to flow between the cavity 48 and the outer portion of the second tubular element 44. In particular, the embodiment of Fig. 4 is designed so that air can pass from the cavity 48 through the opening 52 and into the aerosol generating element 12.

In addition, the second tubular element 44 comprises a second end wall 54 at the second end of its tubular main part 46. This second end wall 54 is formed by bending the end part of the second tubular element 44 at the second end of the tubular main part 46. The second end wall 54 defines the boundaries of an opening 56, which also passes the flow of air between the cavity 48 and the outer part of the second tubular element 44. In the case of the second end wall 54, the opening 56 is designed so that air can pass from outside the article 300 generating an aerosol, through the opening 56 and into the cavity 48. Therefore, the opening 56 provides a channel through which air can be drawn into the article 300 generating an aerosol and through the element 12 generating an aerosol.

In the embodiment shown in Fig. 4, the downstream end of the second tubular element 44 abuts the upstream end of the aerosol-generating substrate rod 12. The second tubular element 44 has a length of approximately 5 millimeters. The RTD of the second tubular element 44 is approximately 5 millimeters of water.

Claims (14)

1. An aerosol-generating article comprising an aerosol-generating substrate, a downstream section extending from a downstream end of the aerosol-generating substrate to a downstream end of the aerosol-generating article, wherein the downstream section comprises a ventilation zone for providing ventilation to the downstream section, wherein the ventilation zone extends from the downstream end to an upstream end, wherein the upstream end is less than 5 millimetres from the downstream end of the aerosol-generating substrate, wherein the draw resistance of the downstream section is less than 10 mm H2O and wherein the ventilation zone comprises a porous portion of the downstream section with a ventilation of at least 20 percent. 2. The aerosol generating article of claim 1, further comprising a wrapper surrounding at least a portion of the downstream section, wherein the ventilation zone comprises a porous portion of the wrapper. 3. An aerosol generating article according to claim 2, characterized in that the wrapper is a paper wrapper and the ventilation zone contains a portion of porous paper. 4. An aerosol-generating article according to paragraph 2 or 3, characterized in that the porous portion of the wrapper that forms a ventilation zone has a basic weight that is less than that of the portion of the wrapper that does not form part of the ventilation zone. 5. An aerosol generating article according to any of the preceding claims, characterized in that the downstream end of the ventilation zone is located at a distance of less than 3 millimeters from the downstream end of the aerosol generating substrate. 6. An aerosol generating article according to any of the preceding claims, characterized in that the upstream end of the ventilation zone is located at a distance of less than 1 millimeter from the downstream end of the aerosol generating substrate. 7. An aerosol generating article according to any of the preceding claims, characterized in that the ventilation zone has a length of at least 2 millimeters. 8. An aerosol generating article according to any one of the preceding claims, wherein the downstream section comprises an unobstructed path for air flow from the downstream end of the aerosol generating substrate to the downstream end of the downstream section. 9. An aerosol generating article according to any one of the preceding claims, characterized in that the downstream section has a length of at least 15 millimeters. 10. An aerosol generating article according to any of the preceding claims, characterized in that the downstream end of the ventilation zone is located at a distance of at least 10 millimeters from the downstream end of the aerosol generating article. 11. An aerosol generating article according to any one of the preceding claims, wherein the upstream end of the ventilation zone is located at a distance of less than 15 percent of the path along the length of the downstream section from the downstream end of the aerosol generating substrate. 12. An aerosol generating article according to any of the preceding claims, characterized in that the downstream section comprises a hollow tubular element. 13. An aerosol generating article according to claim 12, characterized in that the hollow tubular element is located at a distance from the downstream end of the aerosol generating substrate, and the hollow tubular element is connected to the aerosol generating substrate by means of a portion of the porous paper wrapper. 14. An aerosol generating system comprising an aerosol generating device comprising a heater and an aerosol generating article according to any one of the preceding claims.