RU2840404C1 - Aerosol-generating article with low resistance to draw and improved taste delivery - Google Patents

Abstract

FIELD: smoking accessories.

SUBSTANCE: proposed invention relates to an aerosol-generating article adapted to produce an inhaled aerosol when heated. Aerosol generating article extending from a mouth end to a distal end, comprising an aerosol generating element, and a downstream section located downstream of the aerosol generating element. Downstream section extends from the downstream end of the aerosol-generating element to the mouth end of the aerosol-generating article. Downstream section draw resistance (RTD) is less than 10 mm H₂O. From 5 to 35 percent of the length of the downstream section contains the first section forming the first empty section for air passage. At least 65 percent of the length of the downstream section comprises a second section forming a second empty section for air passage. Total cross-sectional area of the first empty section formed by the first section is less than the total cross-sectional area of the second empty section formed by the second section.

EFFECT: obtaining an article for use in combination with an external heating system, characterized by improved aerosol generation and delivery of the aerosol-forming substance with satisfactory low RTD variability from one article to another.

15 cl, 4 dwg, 17 ex

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 burned 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 placed 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.

In a number of prior art documents, aerosol generating devices for consuming aerosol generating articles are disclosed. 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, which comprise an internal heating plate, which is adapted to be inserted into an aerosol generating substrate. As an alternative, inductively heated aerosol generating articles have been proposed in WO 2015/176898, comprising an aerosol generating substrate and a current collector, which is located inside 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 articles in which the tobacco-containing substrate is heated rather than combusted create a number of problems that have not been encountered with conventional smoking articles. First, the tobacco-containing substrates are typically heated to significantly lower temperatures than those reached by the combustion front in a conventional cigarette. This may 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 it reaches the consumer. However, technical solutions that are widely used to cool the mainstream smoke in conventional smoking articles, such as the provision of a highly efficient filtration segment at the mouth end of a cigarette, may have undesirable effects on an aerosol-generating article in which the tobacco-containing substrate is heated rather than combusted, as they may reduce nicotine delivery.

In order to solve one or more problems specifically related to heating, rather than burning, an aerosol-generating substrate to generate an aerosol, a number of aerosol-generating articles have been proposed in which several elements are combined, for example in a longitudinal alignment, with an aerosol-generating element containing an aerosol-generating substrate. As an example, an 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 temperature of the aerosol, a low-filtration mouthpiece element, etc.

There is generally a need for aerosol generating products that are easy to use, have 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 balanced and economical. There is also a need for an aerosol generating product that is particularly suitable for use in combination with an external heating system, and in particular one that has improved aerosol generation and delivery of aerosol forming agent.

It would therefore be desirable to provide a new and improved aerosol generating article adapted to satisfy at least one of the needs described above. It would also 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.

The present invention relates to an aerosol generating article extending from a mouth end to a distal end. 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 article may comprise a downstream section located downstream of the aerosol generating element. The downstream section may extend from a downstream end of the aerosol generating element to the mouth end of the aerosol generating article. The RTD of the downstream section may be less than about 10 mm H2O. From about 5 to about 35 percent of the length of the downstream section may comprise a first section (or first segment) defining a first void for air to pass through. At least approximately 65 percent of the length of the downstream section may comprise a second section (or second segment) that forms a second void for air to pass through. 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.

Moreover, the present invention may relate to an aerosol generating article extending from a mouth end to a distal end. 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 article may comprise a downstream section located downstream of the aerosol generating element. The downstream section may extend from a downstream end of the aerosol generating element to the mouth end of the aerosol generating article. The RTD of the downstream section may be less than about 10 mm H2O. From about 5 to about 35 percent of the length of the downstream section may comprise a first section (or a first segment, as described above) having an RTD that is less than about 10 mm H2O. At least approximately 65 percent of the length of the downstream section may comprise a second section (or second segment) having an RTD of approximately 0 mm H2O.

According to the present invention, an aerosol generating article is provided for producing an inhalable aerosol upon heating, extending from a mouth end to a distal end. The aerosol generating article comprises an aerosol generating element. The aerosol generating article comprises a downstream section located downstream of the aerosol forming element. The downstream section extends from the downstream end of the aerosol forming element to the mouth end of the aerosol generating article. RTD of the downstream section is less than 10 mm H2O. From 5 to 35 percent of the length of the downstream section comprises the first section forming the first empty section for air to pass through. At least 65 percent of the length of the downstream section comprises the second section forming the second empty section for air to pass through. The total cross-sectional area of the first empty section formed by the first section is less than the total cross-sectional area of the second empty section formed by the second section.

The aerosol generating article according to the present invention therefore provides a new configuration of the aerosol generating section downstream of the aerosol generating element rod, which is characterized by having an RTD of less than 10 mm H2O. This particularly low RTD downstream of the aerosol generating element is combined with a relatively short downstream segment forming a void region, which ensures that such a low RTD is maintained simultaneously with providing a physical barrier.

Providing a downstream section having such a low RTD has the effect that substantially all of the RTD of the aerosol generating article can be provided by the aerosol generating rod itself and, if present, by a section located upstream of the aerosol generating rod. The inventors of the present invention have found that when the aerosol generating article has an aerosol generating rod with the geometric properties described above and one such RTD distribution along the length of the article, it is advantageously possible to optimize the delivery of the aerosol to the consumer, especially if the article is used in combination with an external heating system.

The inventors of the present invention have also found that providing from 5 to 35 percent of the length of the downstream section with a first section defining a first void for air to pass through and at least 65 percent of the length of the downstream section with a second section defining a second void for air to pass through, and if the total cross-sectional area of the first void defined by the first section is less than the total cross-sectional area of the second void defined by the second section, ensures that the first section of the downstream section provides sufficient void space for air to pass through such that it does not increase the RTD of the downstream section, while providing a physical barrier to retain any portions of the aerosol generating element from accidentally exiting the aerosol generating article through the mouth end during use by a consumer, which may include the application of suction pressure by the consumer through the aerosol generating article. If the second section comprises at least one hollow tubular element and if the second empty portion is formed by at least one hollow tubular element, the second empty portion is a cavity that provides an unobstructed air flow channel extending along the longitudinal direction of the aerosol-generating article. The first section of the downstream section that forms the empty portion or space tends to provide minimal restriction of the air flow while preventing the material of the aerosol-generating element, such as tobacco, from escaping from the aerosol-generating article.

Additionally, since providing such a low RTD downstream of the aerosol generating rod can be achieved by providing a hollow tubular element downstream of the aerosol generating rod, a substantially empty volume is provided within the article that facilitates nucleation and growth of aerosol particles, while the RTD is substantially eliminated. This can further enhance aerosol generation and delivery compared to existing articles.

According to the present invention, an aerosol generating article is provided for generating an inhalable aerosol upon heating. The aerosol generating article comprises an element comprising an aerosol generating substrate.

The term "aerosol-generating article" is used herein to refer to an article in which an aerosol-generating substrate is heated to produce and deliver an inhalable aerosol to a user. As used herein, the term "aerosol-generating substrate" refers to a substrate that is capable of releasing volatile compounds when heated to generate an aerosol.

A conventional cigarette is lit when a 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 the oxygen in the air drawn through the cigarette causes the end of the cigarette to ignite, 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 transferring heat 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 heater plate which is adapted to be inserted into a rod of a substrate generating the aerosol. 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 have the form of a rod made of or containing an aerosol generating substrate. In the context of this document, in relation to the present invention, the term "rod" is used to describe a substantially cylindrical element with a substantially circular, oval or elliptical cross-section.

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

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

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

The aerosol generating article further comprises a downstream section at a location downstream of the aerosol generating substrate rod. 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 mouth 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 with reference to a tubular element that has a substantially cylindrical cross-section and defines 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 or segment provides an unobstructed flow path. This means that the hollow tubular segment provides an insignificant level of resistance to draw (RTD). The term "insignificant level of 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, 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 the longitudinal flow of air. Preferably, the flow channel is substantially empty.

In some embodiments, the aerosol-generating article may comprise a ventilation zone at a location along the downstream section. In more detail, the aerosol-generating article may comprise a ventilation zone at a location along the hollow tubular element. In this way, fluid communication is established between the flow channel formed inside 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 element comprising 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. As an example, the aerosol generating element may comprise a rod of aerosol generating substrate surrounded by a wrapper.

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

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

In particularly preferred embodiments, the rod containing 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, even more preferably less than or equal to about 25 millimeters. In particularly preferred embodiments, the rod containing 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 rod containing the aerosol-generating substrate has a length of about 5 millimeters to about 60 millimeters, preferably about 6 millimeters to about 60 millimeters, more preferably about 7 millimeters to about 60 millimeters, even more preferably about 10 millimeters to about 60 millimeters, most preferably about 12 millimeters to about 60 millimeters. In other embodiments, the rod containing the aerosol-generating substrate has a length of about 5 millimeters to about 55 millimeters, preferably about 6 millimeters to about 55 millimeters, more preferably about 7 millimeters to about 55 millimeters, even more preferably about 10 millimeters to about 55 millimeters, most preferably about 12 millimeters to about 55 millimeters. In further embodiments, the rod containing 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 rod containing the aerosol-generating substrate has a length of about 5 millimeters to about 30 millimeters, preferably about 6 millimeters to about 30 millimeters, more preferably about 7 millimeters to about 30 millimeters, even more preferably about 10 millimeters to about 30 millimeters. In other particularly preferred embodiments, the rod containing the aerosol-generating substrate has a length of about 5 millimeters to about 20 millimeters, preferably about 6 millimeters to about 20 millimeters, more preferably about 7 millimeters to about 20 millimeters, even more preferably about 10 millimeters to about 20 millimeters. In further particularly preferred embodiments, the rod containing 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 rod containing the aerosol generating substrate preferably has an outer diameter that is approximately equal to the outer diameter of the aerosol generating article.

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

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

In general, it has been observed that the smaller the diameter of the rod containing the aerosol generating substrate, the lower the temperature required to raise the temperature of the core of the aerosol generating element so that sufficient amounts of the evaporable components are released from the aerosol generating substrate to form the desired amount of aerosol. At the same time, without wishing to be limited by theory, it is understood that a smaller diameter of the rod containing the aerosol generating substrate provides a faster penetration of the heat supplied to the aerosol generating article into the entire volume of the aerosol generating substrate. However, when the diameter of the rod containing the aerosol generating substrate is too small, the volume to surface ratio of the aerosol generating substrate becomes less favorable since the amount of available aerosol generating substrate is reduced.

The diameter of the rod containing the aerosol generating substrate falling within the ranges described in this document is particularly advantageous in terms of the balance between energy consumption and aerosol delivery. This advantage is felt in particular when the aerosol generating article containing the rod containing the aerosol generating substrate having a diameter as described in this document is used in combination with an external heater located at 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 rod containing 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 time frame and by means of lower energy consumption.

In some embodiments, the rod containing 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 rod containing 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 rod containing 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.

In particularly preferred embodiments, the rod containing the aerosol-generating substrate has an outer diameter of less than about 7.5 millimeters. As an example, the rod containing the aerosol-generating substrate may have an outer diameter of about 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 1.9, 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 total length of the aerosol generating article may be at least about 0.10. Preferably, the ratio between the length of the aerosol generating element and the total length of the aerosol generating article is at least about 0.15. More preferably, the ratio between the length of the aerosol generating element and the total length of the aerosol generating article is at least about 0.20. Even more preferably, the ratio between the length of the aerosol generating element and the total length of the aerosol generating article is at least about 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 overall 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 still further 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 0.30, 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 length of the rod. 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 may 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 yet 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 may 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 about 200 milligrams/cubic centimeter. Preferably, the density of the aerosol generating substrate is less than or equal to about 185 milligrams/cubic centimeter. More preferably, the density of the aerosol generating substrate is less than or equal to about 170 milligrams/cubic centimeter. Even more preferably, the density of the aerosol generating substrate is less than or equal to about 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 aerosol generating substrate. In some embodiments, the aerosol generating element comprises from about 210 milligrams to about 230 milligrams of aerosol generating substrate, preferably from 215 milligrams to about 220 milligrams of aerosol generating substrate. In other embodiments, the aerosol generating element comprises from about 150 milligrams to about 180 milligrams of aerosol generating substrate, preferably from 160 milligrams to about 165 milligrams of 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.

In the context of this document, 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 obtained by casting processes, extrusion processes, papermaking processes 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" in relation to the present invention describes a layered element having a width and a length that are substantially greater than its thickness.

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

The homogenized plant material may be in the form of a plurality of strands, strips or pieces. In the context 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 considered as covering strips, pieces and any other homogenized plant material having a similar shape. The strands of homogenized plant material may be formed from a sheet of homogenized plant material, for example by cutting or dividing into pieces or by other methods, for example by an extrusion method.

In some embodiments, the filaments may be formed in situ within the aerosol-generating substrate as a result of separating or splitting a sheet of homogenized plant material during the formation of the aerosol-generating substrate, such as by pleating. The filaments of homogenized plant material within the aerosol-generating substrate may be separated from each other. 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 as a result of separating a sheet of homogenized plant material during the production of the aerosol-generating substrate, as described above.

If the aerosol generating substrate comprises homogenized plant material, the homogenized plant material can generally be provided in the form of one or more sheets. In particular, the sheets of homogenized plant material can be obtained by a casting process. Preferably, the sheets of homogenized plant material can be obtained by a paper manufacturing process.

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

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

Preferably, the cut 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 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 relation to the present invention, the term "tobacco" describes any plant belonging to the genus Nicotiana.

Light tobacco varieties are tobacco varieties with generally large, light-colored leaves. Throughout the technical description, the term light tobacco is used for tobacco varieties that have been flue-cured. Examples of light tobacco varieties are Chinese flue-cured, Brazilian flue-cured, American flue-cured such as Virginia tobacco, Indian flue-cured, Tanzanian flue-cured, or other African flue-cured. Light tobacco is characterized by a high sugar to nitrogen ratio. From an organoleptic standpoint, 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 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. The total ammonia content includes, for example, ammonia and ammonia salts.

Dark tobacco varieties are tobacco varieties with typically large, dark colored leaves. Throughout the technical description, the term "dark tobacco" is used for varieties of tobacco that have been air-cured. Additionally, dark tobacco varieties may be fermented. Varieties of tobacco that are used primarily for chewing, snuff, cigars, and pipe blends are also included in this category. As a rule, these dark tobacco varieties are air-cured and possibly fermented. From an organoleptic point of view, dark tobacco is a type of tobacco that, after curing, is associated with a sensation similar to that of the smoke of dark cigars. Dark tobacco is characterized by a low sugar to nitrogen ratio. Examples of dark tobacco are Malawi Burley or other African Burley, dark cured Brazilian Galpao, and sun-cured 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 varieties of tobacco that often have small, light-colored leaves. Throughout the technical description, the term "aromatic tobacco" is used for other varieties of tobacco that are characterized by a high content of aromatic substances, such as essential oils. From an organoleptic point of view, aromatic tobacco is a type of tobacco that, after curing, is associated with a spicy and aromatic sensation. Examples of aromatic tobacco varieties are Greek Oriental, Turkish Oriental, semi-Oriental tobacco, but also fire-cured tobacco, American Burley 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 characteristic aromatic property to the final product. Examples of filler tobacco are 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 for conventional smoking articles. The cut width of the cut filler is preferably from 0.3 millimeters to 2.0 millimeters, more preferably the cut width of the cut filler is from 0.5 millimeters to 1.2 millimeters, and most preferably the cut width of the cut filler is from 0.6 millimeters to 0.9 millimeters. The cut width may play a role in the distribution of heat within the aerosol generating element. Also, the cut width may play a role in the resistance to draw of the article. In addition, the cut width may affect the overall density of the aerosol generating substrate as a whole.

The length of the threads of the cut filler is to some extent a random value, since the length of the threads will depend on the overall size of the object from which the thread is cut. However, by maintaining appropriate conditions for the material before cutting, for example, by controlling the moisture content and the overall fineness of the material, longer threads can be cut. Preferably, the threads have a length of from about 10 millimeters to about 40 millimeters before the threads are combined 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 the section is less than 40 millimeters, the final aerosol generating element can 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 about 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, more preferably from 170 milligrams to 220 milligrams. This amount of cut filler usually allows to obtain enough material to form an aerosol. Additionally, in light of the above-mentioned limitations on diameter and size, this ensures a balanced density of the aerosol generating element between energy absorption, resistance to draw and fluid passages in 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 carried out by spraying or other suitable application methods. The aerosol forming agent can be added to the mixture when preparing the cut filler. For example, the aerosol forming agent can be added to the mixture in a direct conditioning housing 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 facilitates the formation of a dense and stable aerosol when used. The aerosol forming agent can provide substantially resistance of the aerosol to thermal degradation at temperatures typically encountered when using 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 the 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 the aerosol forming agent is from 8 percent to 18 percent by weight based on the dry weight of the cut filler, most preferably, the amount of the 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 sticky. This advantageously helps to hold the cut filler in a given location inside the article, since the particles of the cut filler show a tendency to stick to the surrounding particles of the cut filler, as well as to the surrounding surfaces (for example, the inner surface of the wrapper surrounding the cut filler).

In some embodiments, the amount of aerosol forming agent has a target value of 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, regardless of 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 amounts of aerosol at relatively low temperatures. Temperatures of 150 degrees Celsius to 200 degrees Celsius in the heating chamber are sufficient for one such cut filler to generate sufficient amounts of aerosol, while aerosol generating devices that use sheets of molded tobacco leaves typically use temperatures of approximately 250 degrees Celsius.

An additional benefit associated with 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 product.

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 as described herein may individually have a thickness of from about 100 micrometers to 600 micrometers, preferably from 150 micrometers to 300 micrometers, and most preferably from 200 micrometers to 250 micrometers. The individual thickness refers to the thickness of an individual sheet, while the aggregate 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, then the aggregate 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. In the context of this document, the term "assembled" is used to describe a sheet of homogenized plant material that is rolled, bent 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" means a sheet having a plurality of substantially parallel folds or corrugations. Alternatively or in addition to corrugating, 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 may be corrugated so 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 may be collected. It will be understood that the corrugated sheets of homogenized plant material may alternatively or additionally have a plurality of substantially parallel folds or corrugations arranged at an acute or obtuse angle to the cylindrical axis of the plug. The sheet may be corrugated to such an extent that the integrity of the sheet is disrupted at the plurality of parallel folds or corrugations, which causes separation of the material 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 about 5 millimeters, or about 4 millimeters, or about 3 millimeters, or about 2 millimeters or less. The length of the threads can be greater than about 5 millimeters, from about 5 millimeters to about 15 millimeters, from about 8 millimeters to about 12 millimeters, or about 12 millimeters. Preferably, the threads have substantially the same length relative to each other.

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 comprising 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 basis, more preferably at least about 50 percent by weight on a dry basis, more preferably at least about 70 percent by weight on a dry basis, and most preferably at least about 90 percent by weight on a dry basis.

For purposes of the present invention, the term "tobacco particles" describes particles of any plant belonging to the genus Nicotiana. The term "tobacco particles" includes 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 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 evaporation, the aerosol forming agent may carry other vaporized compounds released from the aerosol generating substrate upon heating, such as nicotine and flavoring agents, 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 electrical aerosol-generating system having a heating element, it may preferably comprise an aerosol-forming substance content of from about 5 percent to about 30 percent by weight on a dry weight basis. If the substrate is intended for use in an aerosol-generating article for an electrical aerosol-generating system having a heating element, the aerosol-forming substance 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 substances from the aerosol-generating substrate in the aerosol.

In other embodiments, the homogenized plant material may have an aerosol former content of from about 30 percent by weight to about 45 percent by weight. This relatively high level of aerosol former 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 homogenized plant material 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 former 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 homogenized plant material that does not originate from non-tobacco plant particles or tobacco particles provided in the homogenized plant material. Therefore, the additional cellulose is included in the homogenized plant material 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 cellulosic 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.

Supplementary 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 a plurality of layers. Preferably, the wrapper is formed from a multi-layer sheet comprising a layer of aluminum. The use of a multi-layer sheet comprising 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 comprises an alkaloid compound or 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 comprises 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.

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

The gel composition described herein may be combined with an aerosol generating device to deliver a nicotine aerosol to the lungs at inhalation or air flow rates that are within the inhalation or air flow rates of a typical smoking regimen. The aerosol generating device may continuously heat the gel composition. The user may inhale several inhalations or "puffs," where each "puff" delivers a certain amount of nicotine aerosol. The gel composition may be capable of delivering a high nicotine/low total particulate matter (TPM) 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 substantially release (release moisture) or absorb water when exposed to standard temperature and pressure when the relative humidity changes from about 10 percent to about 60 percent. For example, a stable gel may substantially maintain its shape and mass when exposed to standard temperature and pressure when the relative humidity changes from about 10 percent to about 60 percent.

The gel composition comprises an alkaloid compound or a cannabinoid compound, or both an alkaloid compound and a cannabinoid compound. The gel composition may comprise one or more alkaloids. The gel composition may comprise one or more cannabinoids. The gel composition may comprise 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 may 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, for example, a heterocyclic ring. In nature, alkaloid compounds are found primarily in plants and are especially common in certain families of flowering plants. However, some alkaloid compounds are found in animal species and in fungi. As used herein, 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, namely, 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 comprising 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 is heated during use. Further 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 about 10 millimeters. For example, the downstream section may have a length of at least about 15 millimeters, at least about 20 millimeters, at least about 25 millimeters, or at least about 30 millimeters.

Providing a downstream section that has a length that is greater than the values set out 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 article is used in conjunction with the aerosol generating device.

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

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

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

The RTD of the downstream section may be no more than about 100 mmH2O. For example, the RTD of the downstream section may be no more than about 50 mmH2O, no more than about 25 mmH2O, no more than about 15 mmH2O, no more than about 10 mmH2O, no more than about 8 mmH2O, no more than about 5 mmH2O, or no more than about 1 mmH2O.

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 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 approximately 0.5 millimeters. For example, the unobstructed air flow path may have a minimum diameter of 1 millimeter, 2 millimeters, 3 millimeters, or 5 millimeters.

The downstream section may comprise a hollow tube segment. The hollow tube segment may be referred to as a hollow tube, a hollow tubular element, or a hollow tubular segment.

Providing a hollow segment in the form of a tube can advantageously provide the desired overall length of the aerosol generating article without unacceptably increasing the draw resistance.

The hollow tube may extend from the downstream end of the 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 tube segment. When this is the case, it will be understood that the lengths and length ratios stated above relative to the downstream section apply equally to the length of the hollow tube segment.

The hollow tube-shaped segment may abut against the downstream end of the aerosol generating article.

The hollow tube segment may be located at a distance from the downstream end of the aerosol generating article. When this is the case, there may be a void space between the downstream end of the aerosol generating substrate and the upstream end of the hollow tube segment.

The hollow tube segment may have an internal diameter. The hollow tube segment may have a constant internal diameter along the length of the hollow tube segment. The internal diameter of the hollow tube segment may vary along the length of the hollow tube segment.

The hollow tube segment may have an internal diameter of at least about 2 millimeters. For example, the hollow tube segment may have an internal diameter of at least about 4 millimeters, at least about 5 millimeters, or at least about 7 millimeters.

Providing a hollow segment in the form of a tube having an inner diameter as stated above can advantageously ensure sufficient rigidity and strength for the hollow segment in the form of a tube.

The hollow tube segment may have an internal diameter of no more than about 10 millimeters. For example, the hollow tube segment may have an internal diameter of no more than about 9 millimeters, no more than about 8 millimeters, or no more than about 7.5 millimeters.

Providing the hollow segment in the form of a tube having an inner diameter as stated above can advantageously reduce the tightening resistance of the hollow tubular segment.

The hollow tube segment 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 tube-shaped segment may have an internal diameter of approximately 7.1 millimeters.

The ratio between the inner diameter of the hollow tube segment and the outer diameter of the hollow tube segment may be at least approximately 0.8. For example, the ratio between the inner diameter of the hollow tube segment and the outer diameter of the hollow tube segment 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 tube segment and the outer diameter of the hollow tube segment may be no more than about 0.99. For example, the ratio between the inner diameter of the hollow tube segment and the outer diameter of the hollow tube segment may be no more than about 0.98.

The ratio between the inner diameter of the hollow tube segment and the outer diameter of the hollow tube segment may be approximately 0.97.

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

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

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

When the hollow tubular segment comprises cellulose acetate tow, the cellulose acetate tow may have a denier per fiber of from about 2 to about 4 and an overall denier of from about 25 to about 40.

The hollow tubular segment may comprise paper. The hollow tubular segment may comprise at least one layer of paper. The paper may be a very rigid paper. The paper may be a corrugated paper, such as a corrugated heat-resistant paper or a corrugated parchment paper. The paper may be cardboard. The hollow tubular segment may be a paper tube. The hollow tubular segment may be formed as a tube of 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 segment may comprise a polymer. For example, the hollow tubular segment may comprise a polymer film. The polymer film may comprise a cellulose film. The hollow tubular segment may comprise low-density polyethylene (LDPE) or polyhydroxyalkanoate (PHA) fibers.

The downstream section may contain ventilation. The ventilation may be provided to allow cooler air from outside the aerosol generating article 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 about 80 percent. More preferably, the aerosol generating article has a ventilation level of less than about 60 percent or less than about 50 percent.

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

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

Without being limited by theory, the present inventors have found that a temperature difference caused by introducing cooler external air into a hollow tubular segment 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 and condensation, and droplet coalescence, while taking into account 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 for them to remain coherent for a long time with a sufficient probability (e.g., with a probability of five tenths). These molecules represent some kind of critical threshold molecular clusters among the transient molecular aggregates, which means that, on average, smaller molecular clusters are more likely to disintegrate sufficiently quickly into the gas phase, whereas larger clusters are, on average, more likely to grow. Such a critical cluster is identified with the key nucleation nucleus from which droplet growth is expected due to condensation of molecules from the vapor. Primary droplets that 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, namely mass transfer between a gas and a liquid. Whereas evaporation refers to a net mass transfer from the liquid droplets to the gas phase, condensation is a net mass transfer from the gas phase to the droplet phase. Evaporation (or condensation) will cause a decrease in the volume (or growth) of the droplets, but will not change the number of droplets.

In this scenario, which may be further complicated by droplet coalescence phenomena, temperature and cooling rate may play an important role in determining the response of the system. In general, different cooling rates may result in significantly different time behavior with respect to liquid phase (droplet) formation, since the nucleation process is typically nonlinear. Without being limited by theory, it is suggested that cooling may cause a rapid decrease in the 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. It may also be that higher cooling rates may favor an earlier onset of nucleation. Conversely, a decrease in the cooling rate may have a beneficial effect on the final size that the aerosol droplets eventually reach.

Thus, the rapid cooling caused by the admission of external air into the hollow tubular segment can be advantageously used to promote the nucleation and growth of aerosol droplets. However, at the same time, the immediate disadvantage of admitting external air into the hollow tubular segment is the dilution of the aerosol stream delivered to the consumer.

The inventors of the present invention have surprisingly found that the effect of dilution on the aerosol, which can be measured, in particular the effect on the delivery of the aerosol forming substance (such as glycerol) contained in the aerosol generating substrate, is advantageously minimized when the ventilation level is within the ranges described above. In particular, it has been found that ventilation levels from 25 percent to 50 percent, and even more preferably from 28 to 42 percent, lead to particularly satisfactory values of glycerol delivery. At the same time, the duration of nucleation and, therefore, the delivery of nicotine and the aerosol forming substance (such as glycerol) are improved.

Ventilation into the downstream section may be provided along substantially the entire length of the downstream section. When this is the case, 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 segment, the hollow segment may be formed from a porous material that allows air to enter the interior of the hollow tubular segment. 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 segment.

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 pass compared to the remainder of the downstream section. For example, the first ventilation zone may be 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 the downstream section with a ventilation of at least 5 percent. For example, the first ventilation zone may comprise a porous portion of the 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 a ventilation of no more than 80 percent. For example, the first ventilation zone may comprise a porous portion of a downstream section with a 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 the downstream section with a ventilation of 40 percent to 50 percent. In some particularly preferred embodiments, the first ventilation zone may comprise a porous portion of the downstream section with a ventilation of 45 percent.

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

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

When the aerosol generating article comprises a unifying wick, the ventilation zone preferably comprises at least one corresponding annular row of perforations provided through a portion of the unifying wick. They can also be formed on a production line during the manufacturing process of the smoking article. Preferably, the annular row or rows of perforations provided through a portion of the unifying wick are substantially in alignment 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. They can 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 in alignment 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 about 50 micrometers. For example, the first line of perforations may comprise at least one perforation with a width of at least about 65 micrometers, at least about 80 micrometers, at least about 90 micrometers, or at least about 100 micrometers.

The first line of perforations may comprise at least one perforation with a width of no more than about 200 micrometers. For example, the first line of perforations may comprise at least one perforation with a width of no more than about 175 micrometers, no more than about 150 micrometers, no more than about 125 micrometers, or no more than about 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 perforations 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 of no more than about 1 millimeter. For example, the first line of perforations may comprise at least one perforation with a length of no more than about 950 micrometers, no more than about 900 micrometers, no more than about 850 micrometers, or no more than about 800 micrometers.

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

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

The first line of perforations may comprise at least one perforation with an opening area of about 0.01 square millimeters to about 0.5 square millimeters, about 0.02 square millimeters to about 0.3 square millimeters, about 0.03 square millimeters to about 0.25 square millimeters, or 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 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 tube located at a distance from the downstream end of the aerosol generating substrate. When this is the case, the hollow tube 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 tube. 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 tube.

The porous portion of the wrapper that forms 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 path along the length of the downstream element 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 path along the length of the downstream element 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 path along the length of the downstream element 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 path along the length of the downstream element from the downstream end of the aerosol generating substrate.

The downstream end of the first ventilation zone may be located no further 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 at a distance of no more than 8 millimeters, no more than 5 millimeters, or no more than 3 millimeters from the downstream end of the aerosol-generating substrate. The first ventilation zone may be located at any location along the length of the downstream section. The downstream end of the first ventilation zone may be located at a distance of no more than about 25 millimeters from the downstream end of the aerosol-generating article. For example, the first ventilation zone may be located at a distance of no more than about 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 about 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 about 10 millimeters, at least 12 millimeters, or at least about 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 article is in use.

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

The upstream end of the first ventilation zone may be located at a distance of 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 a distance of 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 at a distance of 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 at a distance of 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 article is in use.

The upstream end of the first ventilation zone may be located at a distance of about 20 millimeters to about 37 millimeters or about 25 millimeters to about 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 about 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 have a length of no more than 10 millimeters. For example, the first ventilation zone may have a length of no more than 8 millimeters or no more than 5 millimeters.

The first ventilation zone may have a length of 0.5 millimeters to 10 millimeters. For example, the first ventilation zone may have a length of 1 millimeter to 8 millimeters or 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. 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 mouth 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 mouth 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 according to 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 of the present invention may form a recessed cavity.

The above-described "additional element" may also be referred to in this specification as a "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 an 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 defining a first void for air passage, and at least about 65 percent of the length of the downstream section may comprise a second section defining a second void for air passage, where the total cross-sectional area of the first void defined by the first section may be less than the total cross-sectional area of the second void defined 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 a relatively low RTD of the downstream section is achieved while providing a downstream component (the first section) that does not significantly increase the RTD and provides a physical barrier that can prevent any material displaced from the aerosol generating element from unintentionally escaping from the mouth end of the aerosol generating article during normal use.

In other words, the downstream section may comprise a first section and a second section. The first section may comprise from about 5 to about 35 percent of the length of the downstream section, and the second section may comprise at least about 65 percent of the length of the downstream section.

The term "empty area" refers to an area or space through which air can pass. For example, a hollow tubular element can form a cavity that provides an empty area. An additional segment can contain several air flow channels formed through the segment, and these several air flow channels can form an empty area inside the additional segment for air to pass through it. A filter segment or a retaining segment, according to the present invention, can also provide an empty area, which is formed by several gaps or air flow channels (of the segment) for air to pass through it, provided inside the material forming the filter segment or the retaining segment.

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. Likewise, 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 in and by the first section of the downstream section. In other words, when the first section comprises the first segment, the at least one air flow path of the segment may be formed in 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 empty section may comprise at least one cavity. At least one cavity may provide an unobstructed air flow 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 empty section may be formed by at least one hollow tubular element. Providing the greater part of the length of the downstream section with at least one hollow tubular element ensures that a relatively low RTD of the downstream section and the aerosol-generating article as a whole is achieved.

The downstream section may comprise a second section comprising two hollow tubular elements and a first section comprising a first segment. The second empty section may be formed by two hollow tubular elements. The first section may be located between 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 empty section. The second empty section may be divided into several empty 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 mouth end of the aerosol generating article. At least one first segment of the first section may be located inside 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 parts 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 parts 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 parts of the cavity, which is located furthest downstream, can 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 parts of the cavity, which is located earliest downstream, can 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 to 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 of the mouth end of the aerosol generating article. Preferably, the first segment may be located downstream of 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 extending from the middle or the 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 located at a position between the vent zone or line (or the vent zone or line that is located furthest downstream) and the mouth end of the article.

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 defines 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 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 located 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 at 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 of the invention, the outer diameter of the hollow tubular element may be approximately 7.3 mm.

The diameter of the first segment may be from about 5 mm to about 10 mm. The diameter of the first segment may be from about 6 mm to about 8 mm. The diameter of the first segment may be from about 7 mm to about 8 mm. The diameter of the first segment may be about 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 inside the hollow tubular element of the second section located downstream of the flow section. The first segment may therefore be surrounded by a wall of the hollow tubular element, preferably impermeable to air so 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 defining 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 defining 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 defining 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 defining 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 defining 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 defining 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 to pass through, 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 to pass through. 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 to pass through, 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 to pass through.

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 millilitres per second at the outlet or downstream end of the component being measured, at 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 total 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, such as 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 be from about 0 mmH2O per mm to about 3 mmH2O per mm. Alternatively, the RTD per unit length of the downstream section may be from about 0 mmH2O per mm to about 2.5 mmH2O per mm. Alternatively, the RTD per unit length of the downstream section may be from about 0 mmH2O per mm to about 2 mmH2O per mm. The RTD per unit length of the downstream section may be from about 0 mmH2O per mm to about 1 mmH2O per mm. The RTD per unit length of the downstream section may be from about 0 mmH2O per mm to about 0.75 mmH2O per mm.

As mentioned above, the relative RTD, or RTD per unit length, of the downstream section may be greater than about 0 mmH2O per mm and less than about 3 mmH2O per mm. Alternatively, the RTD per unit length of the downstream section may be greater than about 0 mmH2O per mm and less than about 2.5 mmH2O per mm. Alternatively, the RTD per unit length of the downstream section may be greater than about 0 mmH2O per mm and less than about 2 mmH2O per mm. The RTD per unit length of the downstream section may be greater than about 0 mmH2O per mm and less than about 1 mmH2O per mm. The RTD per unit length of the downstream section may be greater than about 0 mmH2O per mm and less than about 0.75 mmH2O per mm.

The RTD per unit length of the downstream section may be greater than or equal to about 0 mmH2O per mm. Thus, the RTD per unit length of the downstream section may be from about 0 mmH2O per mm to about 3 mmH2O per mm. Alternatively, the RTD per unit length of the downstream section may be from about 0 mmH2O per mm to about 2.5 mmH2O per mm. Alternatively, the RTD per unit length of the downstream section may be from about 0 mmH2O per mm to about 2 mmH2O per mm. The RTD per unit length of the downstream section may be from about 0 mmH2O per mm to about 1 mmH2O per mm. The RTD per unit length of the downstream section may be from about 0 mmH2O per mm to about 0.75 mmH2O per mm. st. per mm.

The RTD of the downstream section may be greater than or equal to approximately 0 mmH2O and less than approximately 10 mmH2O. The RTD of the downstream section may be greater than or equal to 0 mmH2O and less than approximately 5 mmH2O. The RTD of the downstream section may be greater than or equal to 0 mmH2O and less than approximately 2 mmH2O. The RTD of the downstream section may be greater than or equal to 0 mmH2O and less than approximately 1 mmH2O.

In other words, the RTD of the downstream section may be less than 10 mmH2O. The RTD of the downstream section may be less than 5 mmH2O. The RTD of the downstream section may be less than 2 mmH2O. The RTD of the downstream section may be less than 1 mmH2O. The RTD of the downstream section may be 0 mmH2O or greater.

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. Alternatively, the RTD per unit length of the first section may be from about 0 mm H2O per mm to about 2.5 mm H2O per mm. Alternatively, the RTD per unit length of the first section may be from about 0 mm H2O per mm to about 2 mm H2O per mm. The RTD per unit length of the first section may be from about 0 mm H2O per mm to about 1 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 can be greater than about 0 mmH2O per mm and less than about 3 mmH2O per mm. Alternatively, the RTD per unit length of the first section can be greater than about 0 mmH2O per mm and less than about 2.5 mmH2O per mm. Alternatively, the RTD per unit length of the first section can be greater than about 0 mmH2O per mm and less than about 2 mmH2O per mm. The RTD per unit length of the first section can be greater than about 0 mmH2O per mm and less than about 1 mmH2O per mm. The RTD per unit length of the first section can be greater than about 0 mmH2O per mm and less than about 0.75 mmH2O per mm.

The RTD per unit length of the first section may be greater than or equal to about 0 mm H2O per mm. Thus, the RTD per unit length of the first section may be from about 0 mm H2O per mm to about 3 mm H2O per mm. Alternatively, the RTD per unit length of the first section may be from about 0 mm H2O per mm to about 2.5 mm H2O per mm. Alternatively, the RTD per unit length of the first section may be from about 0 mm H2O per mm to about 2 mm H2O per mm. The RTD per unit length of the first section may be from about 0 mm H2O per mm to about 1 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.

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 or equal to 0 mm H2O and less than approximately 5 mm H2O. The tightening resistance of the first section may be greater than or equal to 0 mm H2O and less than approximately 2 mm H2O. The tightening resistance of the first section may be greater than or equal to 0 mm H2O and less than approximately 1 mm H2O.

In other words, the RTD of the first section (or the first segment forming the first section) may be less than 10 mmH2O. The RTD of the first section may be less than 5 mmH2O. The RTD of the first section may be less than 2 mmH2O. The RTD of the first section may be less than 1 mmH2O. The RTD of the first section may be 0 mmH2O or greater.

The RTD of the first section (or the first segment forming the first section) may be greater than or equal to 0 mm H2O. The RTD per unit length of the first section (or the first segment forming the first section) may be greater than or equal to 0 mm H2O per mm.

The first segment may comprise at least one segment air flow channel extending along the first segment. The segment air flow channel may also be referred to as the segment air flow channel throughout this specification. Preferably, the at least one segment air flow channel extends along the entire length of the first segment. The at least one filter channel may have a substantially circular cross-section. The at least one segment channel may have a substantially Y-shaped or T-shaped cross-section. The first segment may comprise several such segment air flow channels extending along the first segment. The first segment may comprise at least three segment air flow channels. Providing at least one segment air flow channel in the first segment allows the downstream section to provide a relatively low RTD by allowing air to pass through it, while ensuring that the first segment provides a physical barrier to prevent the aerosol generating element material from inadvertently escaping from the mouth end of the aerosol generating article. As mentioned in this description of the invention, the material of the aerosol generating element may comprise a vegetable cut filler, in particular a tobacco cut 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 about 5%. In other words, the open area or the first empty portion formed by the first section or segment may have a total cross-sectional area that is at least about 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 a component. For example, the total cross-sectional area of the cylindrical component may be equal to the area of the circular cross-section calculated based on the outer diameter of the cylindrical component, that is, the amount of area occupied by the cross-section of the component. As another example, in the present invention, the total cross-sectional area of the hollow tubular element may be equal to the area of the circular cross-section calculated based on the outer diameter of the hollow tubular element. The total cross-sectional area of the first empty portion may be the same as the sum of the cross-sectional areas of each of at least one channel of the segment formed by the first segment of the first section located downstream of the flow 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) can 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) can 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) can 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 can 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 can be at least approximately 70%. Additionally, the first segment itself can be porous. Providing a large proportion of the segment channels, or open area, void space or empty area 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 about 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 about 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 about 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 at least about 1.1 (110%), preferably at least about 1.3 (130%), more preferably about 1.5 (150%), even more preferably about 2 (200%) and even more preferably about 2.5 (250%). The inventors of the present invention have found that by providing a relatively long section (the second section) having a larger void area and a smaller void area formed by a relatively short section (the first section) of a downstream section, as defined by the cross-sectional area ratios listed above, the downstream section can provide a physical barrier, by means of the first section, that can prevent any unintended release of material of the aerosol generating element through the mouth end of the aerosol generating article, while ensuring that the low RTD performance of the downstream section is not degraded.

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

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

The first segment can be formed from a fibrous material. The first segment can be formed from a porous material. The first segment can be formed from a biodegradable material. The first segment can be formed from a cellulosic material, such as cellulose acetate. For example, the first segment can be formed from a bundle of cellulose acetate fibers having a denier per fiber of about 10 to about 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 about 12 denier per fiber, which can provide an RTD per unit length of about 0.8 to about 2.5 mm H2O per mm.

The first segment may be formed from a polylactic acid-based material. The first segment may be formed from a bioplastic material, preferably a starch-based bioplastic material. The first segment may 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 that may contain several relatively large air flow channels passing through the first segment material, which provides suitable RTD characteristics.

The first segment may be formed from a sheet of suitable material, corrugated, folded, gathered, woven or bent into an element that forms several channels extending in the longitudinal direction. 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. The 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 longitudinally extending 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 that there is 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, which forms a single unobstructed air flow path 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 about 1 mm. The length of the first segment may be at least about 5 mm. The length of the first segment may not be more than about 15 mm. The length of the first segment may not be more than about 10 mm. The length of the first segment may be from about 1 mm to about 15 mm. The length of the first segment may be from about 5 millimeters to about 15 millimeters. Preferably, the length of the first segment may be from about 1 mm to about 10 mm. The length of the first segment may be about 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 characteristics of the relatively low RTD of the downstream section are not affected by the relatively long first segment having 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 the wrapper at the upstream end of the aerosol-generating article may advantageously retain the aerosol-generating substrate in the aerosol-generating article. This feature may also advantageously prevent users from coming into direct contact with the aerosol-generating substrate.

The wrapper may be mechanically closed at the upstream end of the aerosol-generating article. This may be achieved by folding or twisting the wrapper. An adhesive may be used to close the upstream end of the aerosol-generating article.

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.

Providing for this may advantageously facilitate the manufacture of the aerosol-generating article, since only one piece of wrapper material may be required. Additionally, the use of one piece of wrapper material may eliminate the need for a seam to join two pieces of wrapper material. This may advantageously facilitate manufacture. The absence of a seam may 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 element 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. The upstream element may be referred to as an upstream section.

The aerosol generating article may comprise an air inlet at an upstream end of the aerosol generating article. If the aerosol generating article comprises an upstream element, 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 a 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, such as an RTD of less than about 10 mm H2O, providing 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 located upstream of the 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 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 about 80 mm H2O. For example, the RTD of the upstream section may be no more than about 70 mm H2O, no more than about 60 mm H2O, no more than about 50 mm H2O, or no more than about 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.

The upstream section may advantageously prevent direct physical contact with the upstream end of the aerosol-generating substrate. In particular, when the aerosol-generating substrate comprises a susceptor element, the upstream section may prevent direct physical contact with the upstream end of the susceptor element. This helps prevent the susceptor element from shifting or deforming during handling or transport of the aerosol-generating article. This, in turn, helps maintain the shape and position of the susceptor element. In addition, the presence of the upstream section may help prevent any loss of substrate, which may be advantageous, for example, if the substrate comprises particulate plant material.

The upstream section may also provide an improved appearance to the upstream end of the aerosol-generating article. In addition, 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.

The upstream section 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 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 and the internal cross-sectional area of the aerosol-generating article in the position of the porous plug element.

The porous plug element may be made of a porous material or may comprise a plurality of holes. This may be achieved, for example, by laser perforation. Preferably, the plurality of holes are distributed uniformly over the cross-section of the porous plug element.

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

In alternative embodiments, the upstream section may be formed from a material that is impermeable to air. In such embodiments, the aerosol-generating article may be designed such that air flows into the aerosol-generating substrate rod through suitable venting means provided in the wrapper.

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

If the upstream section comprises a plug of material, the downstream end of the plug of material may be adjacent to the upstream end of the aerosol generating substrate. For example, the upstream section may comprise a plug comprising cellulose acetate that abuts the upstream end of the aerosol generating substrate. This may advantageously help to hold the aerosol generating substrate in place.

If the upstream section comprises a plug of material, the downstream end of the plug of material may be spaced from the upstream end of the aerosol generating substrate. The upstream element may comprise a plug comprising fibrous filter material.

Preferably, the upstream section is formed from a heat-resistant material. For example, the upstream section is preferably formed from a material that withstands temperatures of up to 350 degrees Celsius. This ensures that the upstream section is not adversely affected by the heating means for heating 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 about 1 millimeter. For example, the upstream section may have a length of at least about 2 millimeters, at least about 4 millimeters, or at least about 6 millimeters.

The upstream section may have a length of no more than about 15 millimeters. For example, the upstream section may have a length of no more than about 12 millimeters, no more than about 10 millimeters, or no more than about 8 millimeters.

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

The length of the upstream section may advantageously vary to provide a 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 may be increased to maintain the same overall length of the article.

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 over the 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 instead of the upstream element. The second tubular element may be provided immediately upstream of the aerosol-generating substrate. The second tubular element may abut against the aerosol-generating substrate.

The second tubular element may comprise a tubular main part forming a cavity extending from a first end of the tubular main part located upstream of the flow to a second end of the tubular main part located further downstream. The second tubular element may also comprise a bent end part forming a first end wall at the first end of the tubular main part located upstream of the flow. The first end wall may define the boundaries of an opening that allows air flow between the cavity and the outer part of the second tubular element. Preferably, air can pass 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 the second downstream end of the tubular base portion. The second end wall may define the boundaries of an opening, which may also allow air to flow between the cavity and the outside of the second tubular element. In the case of the second end wall, the opening may be designed such that air may pass from outside the aerosol-generating article through the opening and into the cavity. The opening may therefore provide a channel through which air may be drawn into the aerosol-generating article and through the aerosol-generating substrate.

The upstream section is preferably surrounded by a wrapper. The wrapper surrounding the upstream section is preferably a rigid filament, such as a filament with 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 section.

The present invention also relates to an aerosol generating system. The aerosol generating system may comprise an aerosol generating article according to the present invention. The aerosol generating article may be suitable for producing an inhalable aerosol upon heating. The aerosol generating system may further comprise an aerosol generating device having a distal end and a mouthpiece end. The aerosol generating device may comprise a main part or a housing. The aerosol generating device or the main part of the aerosol generating device may form a device cavity for removably accommodating the aerosol generating article at the mouthpiece end of the device. The aerosol generating device may comprise a heater for heating the aerosol generating element when the aerosol generating article is positioned within the device cavity.

The aerosol generating system of the present invention therefore provides a new arrangement comprising an aerosol generating article having a section located downstream of the aerosol generating element which is characterized by having an RTD below 10 mm H2O.

Providing a downstream section with such a low RTD has the effect that substantially all of the RTD of the aerosol generating article is provided by the aerosol generating element itself and, if present, by a section located upstream of the aerosol generating element. The inventors of the present invention have found that when the aerosol generating article has such an RTD distribution along the length of the article, it is advantageously possible to optimize the delivery of the aerosol to the consumer, especially if the article is used in combination with the aerosol generating device of the present system.

This is desirable because it simplifies the design and operation of both the aerosol generating product and the heating device. It has also been found to make it possible to heat the substrate to lower temperatures without compromising the quality and quantity of aerosol delivered to the consumer.

Additionally, since providing such a low RTD downstream of the aerosol generating rod can be achieved by providing a hollow tubular element downstream of the aerosol generating rod, a substantially empty volume is provided within the article that facilitates nucleation and growth of aerosol particles, while the RTD is substantially eliminated. This can further contribute to improved aerosol generation and delivery compared to existing aerosol generating articles and systems, thereby improving the overall consumer experience.

Providing a downstream section with such a low RTD has the effect that substantially all of the RTD of the aerosol generating article is provided by the aerosol generating element itself (e.g., a rod-shaped aerosol generating element), and not necessarily by elements located upstream of the aerosol generating element. The inventors of the present invention have found that when an aerosol generating article has such an RTD distribution along the length of the article, it is advantageously possible to optimize the delivery of the aerosol to the consumer, especially if the article is used in combination with an external heating system or heater. The delivery of the aerosol can be influenced to some extent by the RTD of the aerosol generating element itself. This is because the aerosol generated in the upstream portion of the aerosol generating element must first pass through the remaining downstream portion of the aerosol generating element. Thus, controlling the geometric properties of the aerosol generating element also allows for more efficient control of aerosol delivery, and overall aerosol delivery is made more consistent from aerosol generating article to aerosol generating article, particularly when used in combination with an external heating system or heater.

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

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

The aerosol generating device may comprise 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 with the cavity of the device. The elongated heater may extend into the cavity of the device. Alternative arrangements for heating will be discussed in more detail below.

The heater may be any suitable type of heater. Preferably, the heater is an external heater.

Preferably, the heater can heat the aerosol-generating article from the outside when it is placed inside the aerosol-generating device. Such an external heater can surround the aerosol-generating article when it is inserted into the aerosol-generating device or placed inside it. Preferably, the heater can be designed to heat the aerosol-generating article from the outside when it is placed inside the aerosol-generating device. Such an external heater can be designed to surround the aerosol-generating article when it is inserted into the aerosol-generating device or placed inside it.

In some embodiments, the heater is arranged 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 located 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 several heating elements. The heater may comprise at least one resistive heating element. Preferably, the heater comprises several resistive heating elements. Preferably, the resistive heating elements are electrically connected in a parallel arrangement. Advantageously, providing several resistive heating elements electrically connected in a parallel arrangement may 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 may help to reduce or minimize 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 provide 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-AC converter for converting a DC current supplied by a DC power supply into an AC current. The induction coil may be designed to generate a high-frequency oscillating electromagnetic field when receiving the high-frequency oscillating current from the power supply. The induction coil may be designed to generate a high-frequency oscillating electromagnetic field in a 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 current collector. In the context of this document, the term "current collector" refers to an element comprising a material that is capable of converting electromagnetic energy into heat. When the current collector is placed in an alternating electromagnetic field, the current collector heats up. The heating of the current collector may be the result of at least one of hysteresis losses and eddy currents induced in the current collector, depending on the electrical and magnetic properties of the current collector material.

The current-receiving element can be arranged so 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, such as 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, such as 1 to 10 MHz, such as 5 to 7 MHz.

In some embodiments, the current collecting element is located in the aerosol-generating article. In these embodiments, the current collecting element is preferably located in contact with the aerosol-forming substrate. The current collecting element can be located in the aerosol-forming substrate.

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

In some embodiments, the current collecting element is arranged 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 located 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 the elongated current collecting element include graphite, molybdenum, silicon carbide, stainless steels, niobium, aluminum, nickel, nickel compounds, titanium, and composites of metallic materials. Some current collecting elements comprise 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 comprises more than about 5 percent, preferably more than about 20 percent, more preferably more than about 50 percent or more than about 90 percent of 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 in a certain range of operating temperatures below the maximum operating temperature. The operating temperature range is preferably from about 150 degrees Celsius to about 300 degrees Celsius in the heating chamber (or cavity of the device). The operating temperature range of the heater can be from about 150 degrees Celsius to about 250 degrees Celsius.

Preferably, the operating temperature range of the heater may be from about 150 degrees Celsius to about 200 degrees Celsius. More preferably, the operating temperature range of the heater may be from about 180 degrees Celsius to about 200 degrees Celsius. In particular, it has been found that optimal and stable aerosol delivery can be achieved by using an aerosol generating device having an external heater that has an operating temperature range of from about 180 degrees Celsius to about 200 degrees Celsius, wherein the aerosol generating articles have a relatively low RTD (e.g., less than 10 mm H2O), as described throughout this specification.

In embodiments where the aerosol generating article comprises a ventilation zone at a location along a downstream section or hollow tubular element, 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 comprise 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 from approximately 35 millimeters to approximately 100 millimeters.

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

The total length of the aerosol-generating article according to the present invention is preferably less than or equal to 70 millimeters. More preferably, the total length of the aerosol-generating article according to the present invention is preferably less than or equal to 60 millimeters. Even more preferably, the total 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 external diameter of at least 5 millimeters. Preferably, the aerosol generating article has an external diameter of at least 6 millimeters. More preferably, the aerosol generating article has an external diameter of at least 7 millimeters.

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

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

The term "hydrophobic" refers to a surface that exhibits water-repellent properties. One commonly used method of determining this property is by measuring the water contact angle. The "water contact angle" is the angle, typically measured by a liquid, where the liquid/vapor interface meets a solid surface. It quantifies the wettability of the solid surface by the liquid according to Young's equation. Hydrophobicity or 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.

As an 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 have a surface treatment that includes 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 has the form of a hollow cellulose acetate tube and has an internal diameter of approximately 7.1 millimeters. Thus, the thickness of the peripheral wall of the hollow tubular element is approximately 0.1 millimeters. The ventilation zone is provided at a location 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 comprises at least one of the types of aerosol generating substrate described above, such as a plant cut filler, and in particular a tobacco cut filler, homogenized tobacco, a gel composition or a homogenized plant 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, the hollow tubular element is approximately 33 millimeters long. Thus, the total length of the aerosol generating article is approximately 45 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 abut against an upstream element. In addition, 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 has the form of a hollow cellulose acetate tube and has an internal diameter of approximately 7.1 millimeters. Thus, the thickness of the peripheral wall of the hollow tubular element is approximately 0.1 millimeters. The ventilation zone is provided at a location 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 comprises at least one of the types of aerosol generating substrate described above, such as a plant cut filler, and in particular a tobacco cut filler, homogenized tobacco, a gel composition or a homogenized plant 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. The total length of the aerosol-generating article is therefore 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 article generating an aerosol passing from a mouthpiece end to a distal end, comprising:

an aerosol generating element; and

a downstream section located downstream of the aerosol generating element, wherein the downstream section extends from a downstream end of the aerosol generating element to a mouthpiece end of the aerosol generating article, wherein the resistance to draw (RTD) of the downstream section is less than about 10 mm H2O, and

wherein from about 5 to about 35 percent of the length of the downstream section comprises a first section that defines a first void for the passage of air, and wherein at least about 65 percent of the length of the downstream section comprises a second section that defines a second void for the passage of air, wherein the total cross-sectional area of the first void defined by the first section is less than the total cross-sectional area of the second void defined by the second section.

Example 2. An aerosol-generating article according to example 1, wherein the second empty portion comprises at least one cavity, wherein at least one cavity provides an unobstructed air flow channel extending along the longitudinal direction of the aerosol-generating article.

Example 3. An aerosol generating article according to example 1 or 2, wherein the second section of the downstream section comprises at least one hollow tubular element, and wherein the second empty portion is formed by at least one hollow tubular element.

Example 4. An aerosol generating article according to example 3, wherein the thickness of the peripheral wall of at least one hollow tubular element is less than approximately 1.5 millimeters.

Example 5. An aerosol generating article according to any of the previous examples, wherein the first section comprises a first segment, wherein the first segment forms at least one air flow channel of the segment extending along the longitudinal direction of the first segment, and wherein the first empty portion is formed by at least one air flow channel of the segment.

Example 6. An aerosol-generating article according to any of the previous examples, wherein from about 5 to about 25 percent of the length of the downstream section comprises a first section that defines a first void for air to pass through, and wherein at least about 75 percent of the length of the downstream section comprises a second section that defines a second void for air to pass through.

Example 7. An aerosol generating article according to any of the previous examples, wherein the RTD per unit length of the downstream section is from about 0 mm H2O per mm to about 3 mm H2O per mm.

Example 8. An aerosol generating article according to any of the previous examples, wherein the RTD per unit length of the first section is from about 0 mm H2O per mm to about 3 mm H2O per mm.

Example 9. An aerosol generating article according to any of the previous examples, wherein the ratio of the total cross-sectional area of the second empty portion to the total cross-sectional area of the first empty portion is at least approximately 1.1.

Example 10. An aerosol generating article according to any of the previous examples, wherein the ratio of the total cross-sectional area of the first void formed by the first section to the total cross-sectional area of the downstream section is at least about 5 percent.

Example 11. An aerosol generating article according to any of the previous examples, wherein the ratio of the total cross-sectional area of the second void formed by the second section to the total cross-sectional area of the downstream section is at least about 25 percent.

Example 12. An aerosol generating article according to any of the previous examples, wherein the downstream section comprises a ventilation zone at a location along the second section.

Example 13. An aerosol-generating article according to any of the previous examples, wherein the aerosol-generating element comprises cut tobacco filler.

Example 14. An aerosol-generating article according to any of the previous examples, wherein the content of the aerosol-forming substance in the aerosol-generating element is at least about 10 percent by weight.

Example 15. An aerosol generating article according to any of the previous examples, wherein the second section of the downstream section has a length of at least approximately 25 millimeters.

Example 16. An aerosol generating system comprising:

an aerosol generating article according to any of the preceding examples, and

an aerosol generating device configured to receive an aerosol generating article, wherein the aerosol generating device comprises a heater configured to heat the aerosol generating article when it is received within the aerosol generating device.

Example 17. An aerosol generating system according to example 16, wherein the heater of the aerosol generating device is configured to heat the aerosol generating article from the outside when it is placed inside the aerosol generating device.

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

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

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

Fig. 3a is a schematic cross-sectional side view of another aerosol generating article according to an embodiment of the present invention;

Fig. 3b shows a schematic side cross-sectional view of another aerosol generating article according to an embodiment of the present invention; and

each of Figs. 4a-4f show front elevation views of different examples of a mouthpiece segment 50 that may be used in the aerosol generating articles shown in Figs. 3a and 3b.

The aerosol generating article 10 shown in Fig. 1 comprises a rod 12 of an 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 rod 12, to a downstream or mouth end 18, which coincides with the downstream end of the downstream section 14.

The aerosol generating article 10 has a total length of approximately 45 millimeters.

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

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

The hollow tubular member 20 forms a hollow section of the aerosol generating article 10. The hollow tubular member does not substantially affect the overall RTD of the aerosol generating article. In more detail, 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 (basis weight) of at least about 90 grams per square meter. The hollow tubular element 20 forms an internal cavity 22, which extends all the way from the upstream end 24 of the hollow tubular segment 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 aerosol generating article 10 comprises a ventilation zone 30 provided at a location along the hollow tubular element 20. In more detail, the ventilation zone 30 is provided at a distance of approximately 18 millimeters from the downstream end 26 of the hollow tubular element 20. As such, in the embodiment of Fig. 1, the ventilation zone 30 is actually provided at a distance of 18 millimeters from the mouth end 18 of the aerosol generating article 10. The ventilation level of the aerosol generating article 10 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 segment 20.

The aerosol generating article 100 shown in Fig. 2 differs from the aerosol generating article 10 described above only by providing 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.

Above the rod 12 of the aerosol generating substrate and the downstream section 14 at a location downstream of the rod 12, the aerosol generating article 100 comprises an upstream section 40 at a location upstream of the rod 12. Thus, the aerosol generating article 10 extends from a distal end 16 substantially coinciding with the upstream end of the upstream section 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, a downstream end of the upstream element 42 abuts against 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.

In the embodiments of Fig. 3a and 3b, an aerosol generating article similar to that shown in Fig. 1 is shown, but comprising an additional component downstream of the aerosol generating substrate rod 24. Such an additional component consists of a mouthpiece segment 50.

The aerosol generating articles 200, 300 shown in Fig. 3a and 3b differ from the aerosol generating article 10 described above in that the downstream section 14 consists of a first section 58 and a second section 56. The first section 58 comprises a mouthpiece segment 50, and the second section 56 comprises all or part of the hollow tubular element 20. The mouthpiece segment 50 has a length of approximately 6 mm and is located at a distance of at least 1 mm downstream from the ventilation zone 30, which is provided along the hollow tubular element 20 and at a distance of approximately 18 mm from the downstream end 18 of the aerosol generating articles 200, 300. The mouthpiece segment 50 of the first section 58 forms a first empty section (not shown), and the hollow tubular element 20 forms a second empty section 52, which corresponds to the internal cavity 22.

In the aerosol generating article 200 shown in Fig. 3a, the mouthpiece segment 50 is located immediately downstream of the hollow tubular element 20, which has a length of approximately 27 mm. The mouthpiece segment 50 extends from the downstream end of the hollow tubular element 20 to the downstream end of the downstream section 14, which coincides with the mouthpiece end 18 of the aerosol generating article 200.

In the aerosol generating article 300 shown in Fig. 3b, the mouthpiece segment 50 is placed inside the hollow tubular element 20 and in a position along the hollow tubular element 20. The placement of the mouthpiece segment 50 inside the hollow tubular element 20 forms two internal cavities 22a, 22b inside the hollow tubular element 20 and on each side of the mouthpiece segment 50. The outer surface of the mouthpiece segment 50 forms an airtight connection with the surface of the inner wall of the hollow tubular element 20.

The second section 56a, 56b of the downstream section 14 comprises two parts 56a, 56b forming two parts 52a, 52b of the second empty portion which correspond to the internal cavities 22a, 22b formed downstream and upstream of the mouthpiece segment 50. Such two parts 52a, 52b together form the second empty portion 52 which is formed by the second section 56 of the downstream section 14. As shown in Fig. 3b, the length of the hollow tubular element 20 is the same as the length of the downstream section 14, which is approximately 33 mm. The downstream part 22b of the cavity forms a cavity in the form of a recess of the aerosol generating article 300. The length of such a cavity in the form of a recess is approximately 6 mm. The upstream portion 22a of the cavity forms a cavity between the mouthpiece segment 50 and the rod of the aerosol-generating substrate 24. The length of the upstream portion 22a of the cavity is approximately 21 mm.

Fig. 4a shows a mouthpiece segment 50a formed from a bundle of fibers of polylactic acid or acetyl cellulose tow extending longitudinally along the mouthpiece segment 50a. Gaps among the fibers effectively provide air flow channels, and such air flow channels form a first empty section 54a. The cross-sectional area of the mouthpiece segment 50a occupied by fibers is approximately 90% of the total cross-sectional area of the mouthpiece segment 50a, which is the same as the total cross-sectional area of the downstream section 14. The RTD per unit length of the mouthpiece segment 50a is approximately 0.6 mm H2O per mm.

Fig. 4b shows a mouthpiece segment 50b containing a roll of corrugated sheet material based on paper. Longitudinal gaps inside the twisted corrugated sheet material are formed along the entire length of the mouthpiece segment 50b. Such gaps form a first empty section 54b, which is formed by and inside the mouthpiece segment 50b. The RTD per unit length of the mouthpiece segment 50 is approximately 0.25 mm H2O per mm.

In Fig. 4c, a mouthpiece segment 50c is shown, comprising one Y-shaped channel 53c for the air flow of the segment. The Y-shaped channel 53c of the segment can be considered as consisting of three channels connected together along the central axis of the mouthpiece segment 50c by means of the central channel to form one Y-shaped channel 53c for the air flow. The channel 53c forms a first empty section 54c of the mouthpiece segment 50c. The cross-sectional area of the first empty section 54c is approximately 25% of the total cross-sectional area of the mouthpiece segment 50c, which is the same as the total cross-sectional area of the downstream section 14. The mouthpiece segment 50c is formed from cellulose acetate tow. The RTD per unit length of the mouthpiece segment 50c is approximately 0.02 mm H2O per mm.

Fig. 4d shows a mouthpiece segment 50d comprising three air flow channels 53d of the segment. As shown in Fig. 4d, the air flow channels 53d are circular and arranged in a triangular configuration. The air flow channels 53d form a first empty portion 54d of the mouthpiece segment 50d. The total cross-sectional area of the air flow channels 50d is at least approximately 10% of the total cross-sectional area of the mouthpiece segment 50d, which is the same as the total cross-sectional area of the downstream section 14. The mouthpiece segment 50d is formed from cellulose acetate tow.

Fig. 4e shows a mouthpiece segment 50e comprising five air flow channels 53e of the segment. As shown in Fig. 4e, the air flow channels 53e are in the form of annular sectors and are uniformly distributed around the circumference near the outer periphery of the mouthpiece segment 50e. The air flow channels 53e form a first empty portion 54e of the mouthpiece segment 50e. The total cross-sectional area of the air flow channels 53e is approximately 20% of the total cross-sectional area of the mouthpiece segment 50e, which is the same as the total cross-sectional area of the downstream section 14. The mouthpiece segment 50e is formed from cellulose acetate tow. The RTD per unit length of the mouthpiece segment 50e is approximately 0.05 mm H2O per mm.

Fig. 4f shows a mouthpiece segment 50f comprising seven air flow channels 53f. The air flow channels 53f form a first empty portion 54f of the mouthpiece segment 50f. The total cross-sectional area of the air flow channels 53f is at least approximately 80% of the total cross-sectional area of the mouthpiece segment 50f, which is the same as the total cross-sectional area of the downstream section 14. The mouthpiece segment 50f is formed from a bioplastic material. The RTD per unit length of the mouthpiece segment 50f is approximately 0.01 mm H2O per mm.

For the purposes of the present specification and the appended claims, except where otherwise indicated, all numbers expressing quantities, amounts, percentages, etc., are to be understood as modified in all instances by the term "about". Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therebetween that may or may not be specifically recited herein. Therefore, in this context, the number A is understood as A±10% of A. In this context, the number A may be considered to include numerical values that are within the normal standard error for measuring the property that the number A modifies. The number A, in some instances, when used in the appended claims, may vary by the percentages listed above, provided that the amount by which A varies does not materially affect the fundamental and novel characteristic(s) of the claimed invention. Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therebetween that may or may not be specifically recited herein.

Claims (18)

1. An article that generates an aerosol passing from a mouthpiece end to a distal end, comprising: an aerosol generating element; and a downstream section located downstream of the aerosol generating element, wherein the downstream section extends from the downstream end of the aerosol generating element to the mouthpiece end of the aerosol generating article, wherein the resistance to draw (RTD) of the downstream section is less than 10 mm H2O, and wherein from 5 to 35 percent of the length of the downstream section comprises a first section that forms a first void for the passage of air, and wherein at least 65 percent of the length of the downstream section comprises a second section that forms a second void for the passage of air, wherein the total cross-sectional area of the first void formed by the first section is less than the total cross-sectional area of the second void formed by the second section. 2. An aerosol-generating article according to claim 1, characterized in that the second empty section comprises at least one cavity, wherein said at least one cavity provides an unobstructed channel for air flow, passing along the longitudinal direction of the aerosol-generating article. 3. An aerosol generating article according to claim 1 or 2, characterized in that the second section of the section located further downstream comprises at least one hollow tubular element, and wherein the second empty section is formed by said at least one hollow tubular element. 4. An aerosol generating article according to claim 3, characterized in that the thickness of the peripheral wall of said at least one hollow tubular element is less than 1.5 millimeters. 5. An aerosol generating article according to any of the preceding claims, characterized in that the first section comprises a first segment, wherein the first segment forms at least one air flow channel of the segment, extending along the longitudinal direction of the first segment, and wherein the first empty section is formed by said at least one air flow channel of the segment. 6. An aerosol generating article according to any one of the preceding claims, characterized in that from 5 to 25 percent of the length of the downstream section comprises a first section that forms a first void for the passage of air, and at least 75 percent of the length of the downstream section comprises a second section that forms a second void for the passage of air. 7. An aerosol generating article according to any of the preceding claims, characterized in that the RTD per unit length of the downstream section is from 0 mm H2O per mm to 3 mm H2O per mm. 8. An aerosol generating article according to any of the preceding claims, characterized in that the RTD per unit length of the first section is from 0 mm H2O per mm to 3 mm H2O per mm. 9. An aerosol generating article according to any of the preceding claims, characterized in that the ratio of the total cross-sectional area of the second empty portion to the total cross-sectional area of the first empty portion is at least 1.1. 10. An aerosol generating article according to any of the preceding claims, characterized in that the ratio of the total cross-sectional area of the first void formed by the first section to the total cross-sectional area of the downstream section is at least 5 percent. 11. An aerosol generating article according to any one of the preceding claims, characterized in that the ratio of the total cross-sectional area of the second void formed by the second section to the total cross-sectional area of the downstream section is at least 25 percent. 12. An aerosol generating article according to any of the preceding claims, characterized in that the downstream section comprises a ventilation zone at a location along the second section. 13. An aerosol-generating article according to any of the preceding paragraphs, characterized in that the aerosol-generating element contains cut tobacco filler. 14. An aerosol generating article according to any of the preceding claims, characterized in that the content of the aerosol forming substance in the aerosol generating element is at least 10 percent by weight. 15. An aerosol generating article according to any of the preceding claims, characterized in that the second section of the downstream section has a length of at least 25 millimeters.