Aerosol-generating article comprising perforated hollow tubular matrix element

Abstract

An aerosol-generating article (10) comprising: a strip (12) of aerosol-generating substrate, and a downstream section (14) disposed downstream of the strip (12) of aerosol-generating substrate, where the strip (12) of aerosol-generating substrate comprises: a hollow tubular substrate element (40) formed from homogenized tobacco material and defining a longitudinal cavity (44), the longitudinal cavity provides an unrestricted flow passage through the hollow tubular matrix element (40); an outer wrapper (60) defining the hollow tubular matrix element (40) and arranged such that an empty space (90) is defined between at least a portion of an outer surface of the hollow tubular matrix element (40) and the outer wrapper; wherein the hollow tubular matrix element (40) comprises a plurality of perforations (46) providing fluid communication between a longitudinal cavity (44) of the hollow tubular matrix element (40) and an empty space (90) between at least a portion of an outer surface of the hollow tubular matrix element (40) and the outer wrapper (60), wherein the plurality of perforations (46) of the hollow tubular matrix element (40) are formed through a peripheral wall of the hollow tubular matrix element (40), and wherein the outer wrapper (60) comprises a plurality of perforations (66) overlying the hollow tubular matrix element (40).

Description

Technical Field

[0001] The present invention relates to an aerosol-generating article comprising a strip of an aerosol-generating substrate suitable for generating an inhalable aerosol when heated. Background Art

[0002] 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, an aerosol is generated by transferring heat from a heat source to a physically separated aerosol generating substrate or material, which may be positioned in contact with the heat source, inside, around or downstream of the heat source. During the use of the aerosol generating article, volatile compounds are released from the aerosol generating substrate by heat transfer from the heat source and are entrained in the air drawn by the aerosol generating article. When the released compound cools, the compound condenses to form an aerosol.

[0003] Many prior art documents disclose aerosol generating devices for consuming aerosol generating articles. Such devices include, for example, electrically heated aerosol generating devices, in which an aerosol is generated by transferring heat from one or more electric heater elements of the aerosol generating device to an aerosol generating substrate of a heated aerosol generating article. For example, electrically heated aerosol generating devices including internal heater blades have been proposed, and the internal heater blades are suitable for being inserted into the aerosol generating substrate. It is also known to use aerosol generating articles in combination with external heating systems. For example, WO-A-2020 / 115151 describes the provision of external heating elements arranged around the periphery of the aerosol generating article when the aerosol generating article is received in the cavity of the aerosol generating device. As an alternative, WO-A-2015 / 176898 proposes an inductively heatable aerosol generating article, which includes an aerosol generating substrate and a receptor arranged in the aerosol generating substrate.

[0004] In general, it may be difficult to provide efficient heating of an aerosol generating substrate over the entire strip of the entire substrate. The portion of the substrate closest to the heating element will inevitably be heated most efficiently, and the imperfect transfer of heat through the substrate will mean that the portion of the substrate farthest from the heating element may not be heated efficiently. Therefore, the aerosol generation from these portions of the substrate that are not effectively heated is not optimal, and in some cases, portions of the substrate may not reach a sufficiently high temperature to generate an aerosol during use. For example, in the case of using an external heating element to heat the strip of an aerosol generating substrate, as described above, the central portion of the strip of the aerosol generating substrate is unlikely to generate as much aerosol as the outer portion of the strip, and in some cases, may not generate any aerosol. In a word, the aerosol generation from the aerosol generating strip may therefore be inefficient, wherein a portion of the aerosol generating substrate may be wasted.

[0005] In addition, the aerosol-generating substrate generally does not generate an aerosol immediately upon activation of the heating element. This is because there is a warm-up time after activation of the heating element during which the aerosol-generating substrate is heated to the temperature required for aerosol generation. Therefore, there may be a relatively long duration between activation of the heating element and generation of an organoleptically acceptable aerosol for inhalation by the user. Summary of the invention

[0006] Therefore, it is desirable to provide an aerosol generating article having an aerosol generating substrate, which is suitable for providing a more efficient aerosolization of the aerosol generating substrate and reducing the waste of substrate materials such as tobacco. It is also desirable to provide such an aerosol generating article, which can achieve a relatively short preheating time, so that a sensory acceptable aerosol can be delivered to the user shortly after the aerosol generating substrate is heated. It is also desirable to provide such an aerosol generating article, which can provide optimized aerosol delivery from the aerosol generating substrate. It is particularly desirable to provide such an aerosol generating article, which has a relatively simple design so that it can be manufactured and incorporated into existing product designs in a cost-effective manner. It is also desirable to provide such an article, which can be easily adapted so that it can be heated in various types of heating devices (including induction heating devices and resistance heating devices).

[0007] The present disclosure relates to an aerosol generating article. The aerosol generating article may include a strip of an aerosol generating substrate. The aerosol generating article may include a downstream section disposed downstream of the strip of the aerosol generating substrate. The strip of the aerosol generating substrate may include a hollow tubular substrate element. The hollow tubular substrate element may be formed by homogenized tobacco material. The hollow tubular substrate element may define a longitudinal cavity, thereby providing an unrestricted flow channel through the hollow tubular substrate element. The aerosol generating substrate may include an outer wrapper defining the hollow tubular substrate element. The outer wrapper may be arranged so that a blank space is defined between at least a portion of the outer surface of the hollow tubular substrate element and the outer wrapper. The hollow tubular substrate element may include a plurality of perforations. The plurality of perforations may provide fluid communication between the longitudinal cavity of the hollow tubular substrate element and the blank space between at least a portion of the outer surface of the hollow tubular substrate element and the outer wrapper.

[0008] According to the present invention, an aerosol generating article is provided, comprising: a strip of an aerosol generating substrate, and a downstream section arranged downstream of the strip of the aerosol generating substrate, wherein the strip of the aerosol generating substrate comprises: a hollow tubular substrate element, the hollow tubular substrate element is formed by homogenized tobacco material and defines a longitudinal cavity, the longitudinal cavity provides an unrestricted flow channel through the hollow tubular substrate element; an outer wrapper, the outer wrapper defines the hollow tubular substrate element and is arranged so that a blank space is defined between at least a portion of the outer surface of the hollow tubular substrate element and the outer wrapper; wherein the hollow tubular substrate element comprises a plurality of perforations, the plurality of perforations provide fluid communication between the longitudinal cavity of the hollow tubular substrate element and the blank space between at least a portion of the outer surface of the hollow tubular substrate element and the outer wrapper.

[0009] As used herein with reference to the present invention, the term "aerosol-generating article" is used to describe an article comprising an aerosol-generating substrate, which is heated to generate an inhalable aerosol for delivery to a user.

[0010] As used herein with reference to the present invention, the term "aerosol-generating substrate" is used to describe a substrate comprising an aerosol-generating material which is capable of releasing volatile compounds that can generate an aerosol upon heating.

[0011] As used herein with reference to the present invention, the term "aerosol" is used to describe a dispersion of solid particles or liquid droplets, or a combination of solid particles and liquid droplets, in a gas. An aerosol may be visible or invisible. An aerosol may include vapors of a substance that is normally liquid or solid at room temperature, as well as solid particles or liquid droplets, or a combination of solid particles and liquid droplets.

[0012] As used herein with reference to the present invention, the term "rod" is intended to denote a generally cylindrical element having a substantially circular, oval or elliptical cross-section.

[0013] The aerosol-generating article according to the present invention has a downstream end through which the aerosol leaves the aerosol-generating article for delivery to the user in use. The downstream end of the aerosol-generating article may also be referred to as the proximal end or mouth end of the aerosol-generating article. In use, the user directly or indirectly draws on the downstream end of the aerosol-generating article to inhale the aerosol generated by the aerosol-generating article.

[0014] The aerosol-generating article according to the present invention has an upstream end. The upstream end is opposite to the downstream end. The upstream end of the aerosol-generating article may also be referred to as the distal end of the aerosol-generating article.

[0015] Components of aerosol-generating articles according to the invention may be described as being upstream or downstream of each other based on their relative position between an upstream end of the aerosol-generating article and a downstream end of the aerosol-generating article.

[0016] As used herein with reference to the present invention, the term "longitudinal direction" refers to the direction between the upstream end and the opposite downstream end of the aerosol-generating article.

[0017] As used herein with respect to the present invention, the term "lateral" is used to describe a direction perpendicular to the longitudinal direction.

[0018] Unless otherwise stated, as used herein with reference to the present invention, the term "cross-section" is used to refer to a cross-section of an aerosol-generating article or a component thereof.

[0019] As used herein with reference to the present invention, the terms "hollow tubular element" and "hollow tubular matrix element" refer to a generally elongated element defining an inner cavity or airflow passage along its longitudinal axis. In particular, the term "tubular" is used to refer to a tubular element having a substantially cylindrical cross-section and defining at least one airflow conduit that establishes uninterrupted 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 of the tubular element (e.g., alternative cross-sectional shapes) may be possible. The hollow tubular element may be a single discrete element of the aerosol-generating article having a defined length and thickness.

[0020] As used herein with reference to the present invention, the term "homogenised tobacco material" encompasses any material formed by agglomeration of tobacco particles.Homogenised tobacco material may be produced by casting, extrusion, papermaking processes or any other suitable process known in the art.

[0021] As used herein about the present invention, the term "tobacco particles" describes particles of any plant member of the genus Nicotiana. The term "tobacco particles" comprises ground or pulverized tobacco blades, ground or pulverized tobacco leaf stems, tobacco dust, tobacco fines and other granular tobacco by-products formed in the processing, operation and transportation of tobacco. Preferably, tobacco particles are substantially all derived from tobacco blades. By contrast, isolated nicotine and nicotine salts are compounds derived from tobacco, but for purposes of the present invention, are not considered as tobacco particles.

[0022] As described above, the present invention provides a hollow tubular matrix element and an outer wrapper, wherein the outer wrapper defines the hollow tubular matrix element and is arranged such that a blank space is defined between at least a portion of the outer surface of the hollow tubular matrix element and the outer wrapper. Thus, the blank space is located outside the hollow tubular matrix element.

[0023] A plurality of perforations of the wall of the hollow tubular matrix element through which the fluid is communicated, the hollow tubular matrix element defining the longitudinal cavity, the empty space outside the hollow tubular matrix element, and the longitudinal cavity and the empty space are provided can advantageously enable aerosol to be generated and released from both the inner surface and the outer surface of the hollow tubular matrix element. When the consumer draws on the aerosol generating article, the aerosol released into the empty space from the outer surface of the hollow tubular matrix element can be drawn into the longitudinal cavity of the hollow tubular matrix element by a plurality of perforations. This can advantageously increase the amount of aerosol generated from the aerosol generating substrate at each draw. This can also enable to generate a sensory acceptable aerosol faster when starting to heat the aerosol generating substrate. Thus, this can reduce the preheating time of the aerosol generating article. In particular, in the case of heating the aerosol generating substrate with an external heating device, since the outer surface of the hollow tubular matrix element is close to the external heating device, a sensory acceptable aerosol can be generated faster.

[0024] In addition, providing a plurality of perforations that provide fluid communication between the longitudinal cavity and the empty space can advantageously increase the level of turbulence in the longitudinal cavity of the hollow tubular substrate element, for example when a consumer draws on the aerosol-generating substrate. This can enhance the mixing of air and aerosol-forming components released from the hollow tubular substrate element, thereby improving aerosol generation.

[0025] The matrix element of tubular form is provided and can also advantageously optimize the amount of the tobacco material in the aerosol generating matrix, so that when heated, can effectively generate aerosol from the aerosol generating matrix.The tubular form also removes the center portion of the homogenized tobacco material, and the center portion may not be heated as effectively as the outer portion, particularly in the aerosol generating device comprising an external heating device.In a word, compared with the conventional solid rod of homogenized tobacco material, the amount of tobacco material can therefore significantly reduce, and can reduce tobacco waste.For example, it has been found that compared with the amount of the tobacco material used in the matrix solid rod in the conventional aerosol generating article, the amount of the tobacco material in the hollow tubular matrix element for generating an aerosol according to the present invention can be reduced by up to 40%, while keeping the aerosol similar to be delivered to the consumer.

[0026] By controlling the parameters of the hollow tubular substrate element, such as the density and wall thickness of the peripheral wall of the hollow tubular substrate element, the amount of tobacco material provided in the substrate can be easily adapted. In this way, it is possible to adapt the hollow tubular substrate element so that it matches the heating zone of the associated aerosol generating device. Thus, the proportion of the aerosol generating substrate that can be heated to the required temperature for aerosol generation can be maximized, so that the generation of aerosol from the aerosol generating substrate can be optimized.

[0027] The hollow tubular substrate element has a relatively simple structure that can be produced in a simple and cost-effective manner using existing equipment. The hollow tubular substrate element can then be included in an aerosol-generating article together with other components using known assembly methods and equipment.

[0028] As described above, the hollow tubular substrate element is formed from homogenised tobacco material.Preferably, the hollow tubular substrate element is formed from one or more layers of homogenised tobacco material, such as cast leaf.

[0029] Preferably, the hollow tubular substrate element is formed from 2 or more overlapping layers of homogenised tobacco material, more preferably from 3 or more overlapping layers of homogenised tobacco material.

[0030] The hollow tubular matrix element is preferably formed by up to 10 overlapping layers of homogenized tobacco material, more preferably formed by up to 5 overlapping layers of homogenized tobacco material. For example, the hollow tubular matrix element can be formed by about 2 to about 10 overlapping layers of homogenized tobacco material, or by about 3 to about 5 overlapping layers of homogenized tobacco material.

[0031] Preferably, the multiple overlapping layers of homogenised tobacco material directly overlie each other such that adjacent layers are in direct contact with each other, with no intervening layers.

[0032] The multilayer arrangement of layers may provide a relatively dense structure having sufficient structural rigidity to provide the aerosol-generating substrate in an aerosol-generating article without any additional support, such as a carrier layer or internal support members within the longitudinal cavity.

[0033] Preferably, the layer of homogenised tobacco material is in the form of a sheet.As used herein with reference to the present invention, the term "sheet" describes a laminar element having a width and length substantially greater than its thickness.

[0034] The hollow tubular matrix element may have a length of at least about 5 mm, or at least about 7 mm, or at least about 10 mm.

[0035] The hollow tubular matrix element may have a length of up to about 30 mm, up to about 25 mm, or up to about 20 mm.

[0036] For example, the hollow tubular matrix element can have a length between about 5 mm and about 30 mm, or between about 7 mm and about 25 mm, or between about 10 mm and about 20 mm.

[0037] Preferably, the hollow tubular matrix element has a length of about 12 mm.

[0038] As discussed above, the length of the hollow tubular substrate element may advantageously match the longitudinal dimension of a heating element in a corresponding aerosol generating device to be used to heat the aerosol generating article. In this way, as much of the aerosol generating substrate as possible may be heated during use in order to optimize the amount of aerosol that can be generated and reduce the amount of tobacco waste.

[0039] Preferably, the ratio of the length of the hollow tubular substrate element to the overall length of the aerosol-generating article is at least about 0.1. More preferably, the ratio of the length of the hollow tubular substrate element to the overall length of the aerosol-generating article is at least about 0.15. More preferably, the ratio of the length of the hollow tubular substrate element to the overall length of the aerosol-generating article is at least about 0.2.

[0040] Preferably, the ratio of the length of the hollow tubular substrate element to the overall length of the aerosol-generating article is up to about 0.6. More preferably, the ratio of the length of the hollow tubular substrate element to the overall length of the aerosol-generating article is up to about 0.55. More preferably, the ratio of the length of the hollow tubular substrate element to the overall length of the aerosol-generating article is up to about 0.5.

[0041] For example, the ratio of the length of the hollow tubular substrate element to the overall length of the aerosol-generating article may be between about 0.1 and about 0.6, more preferably between about 0.15 and about 0.55, more preferably between about 0.2 and about 0.5.

[0042] Preferably, the outer diameter of the hollow tubular substrate element is smaller than the outer diameter of the aerosol-generating article.

[0043] Preferably, the hollow tubular matrix element may have an outer diameter of at least about 5 mm, or at least about 5.5 mm, or at least 6 mm.

[0044] Preferably, the hollow tubular matrix element may have an outer diameter of up to about 9 mm, or up to about 8 mm, or up to about 7.5 mm.

[0045] For example, the hollow tubular matrix element may have an outer diameter of between about 5 mm and about 9 mm, or between about 5.5 mm and 8 mm, or between about 6 mm and 7.5 mm.

[0046] Preferably, the outer diameter of the hollow tubular matrix element is substantially constant along the length of the hollow tubular matrix. Alternatively, different portions of the hollow tubular matrix element may have different outer diameters.

[0047] As used herein with reference to the present invention, the term "outer diameter" refers to the maximum diameter of an aerosol generating article or a component thereof at a position along the length of the aerosol generating article or a component thereof in the transverse direction of the aerosol generating article. Where a range or value for the outer diameter of an aerosol generating article or a component thereof is described herein, the outer diameter of the aerosol generating article or a component thereof may fall within the same range or have the same value along the entire length of the aerosol generating article or a component thereof. In other words, where a range or value for the outer diameter of an aerosol generating article or a component thereof is described herein, the outer diameter of the aerosol generating article or a component thereof may fall within the same range or have the same value at all positions along the length of the aerosol generating article or a component thereof.

[0048] The outer diameter of the hollow tubular substrate element does not include the width of any other components of the aerosol-generating substrate that are located outside of the hollow tubular substrate element.

[0049] The hollow tubular matrix element has a peripheral wall defining a longitudinal cavity. The wall thickness of the hollow tubular matrix element can be selected based on the desired amount of tobacco material in the hollow tubular matrix. The wall thickness of the hollow tubular matrix element can also be selected to make the hollow tubular matrix element have a sufficiently high rigidity so that it can be self-supporting. The wall thickness of the hollow tubular matrix can also be selected to make the longitudinal cavity have a cross-sectional area that provides a desired resistance to draw (RTD) for the hollow tubular matrix element.

[0050] The hollow tubular matrix element may have a wall thickness of at least about 4% of the outer diameter of the hollow tubular matrix element, or at least about 5% of the outer diameter of the hollow tubular matrix element, or at least about 6% of the outer diameter of the hollow tubular matrix element.

[0051] The hollow tubular matrix element may have a wall thickness of up to about 40% of the outer diameter of the hollow tubular matrix element, or up to about 30% of the outer diameter of the hollow tubular matrix element, or up to about 20% of the outer diameter of the hollow tubular matrix element.

[0052] For example, the hollow tubular matrix element may have a wall thickness of between about 4% to about 40% of the outer diameter of the hollow tubular matrix element, or between about 5% to about 30% of the outer diameter of the hollow tubular matrix element, or between about 6% to about 20% of the outer diameter of the hollow tubular matrix element.

[0053] Preferably, the hollow tubular matrix element has a wall thickness of about 7% of the outer diameter of the hollow tubular matrix element.

[0054] The hollow tubular matrix element may have a wall thickness of at least about 0.3 mm, or at least about 0.35 mm, or at least about 0.4 mm.

[0055] The hollow tubular matrix element may have a wall thickness of up to about 3 mm, or up to about 2 mm, or up to about 1 mm.

[0056] For example, the hollow tubular matrix element may have a wall thickness of between about 0.3 mm and about 3 mm, or between about 0.35 mm and about 2 mm, or between about 0.4 mm and about 1 mm.

[0057] The hollow tubular matrix element may have a wall thickness of about 0.5 mm.

[0058] As described above, the longitudinal lumen provides an unrestricted flow passage through the hollow tubular matrix element. This means that the hollow tubular matrix element provides a negligible level of resistance to suction (RTD). The term "negligible level of RTD" is used to describe an RTD of less than 1 mmH2O / 10 mm length of the hollow tubular matrix element, preferably less than 0.4 mmH2O / 10 mm length of the hollow tubular matrix element, and more preferably less than 0.1 mmH2O / 10 mm length of the hollow tubular matrix element.

[0059] Therefore, the longitudinal cavity should not have any components that hinder the flow of air in the longitudinal direction. Preferably, the longitudinal cavity is substantially empty. More preferably, the longitudinal cavity is empty.

[0060] The longitudinal cavity may also be referred to as a longitudinal air flow channel.

[0061] The longitudinal cavity extends between the ends of the hollow tubular matrix element and is preferably open at both the upstream and downstream ends. The open upstream end can provide a primary air inlet for drawing air through the aerosol-generating article when a consumer draws on the article. Thus, the longitudinal cavity can provide a primary pathway for air and aerosol to flow through the article.

[0062] The diameter of the longitudinal lumen corresponds to the inner diameter of the hollow tubular matrix element.

[0063] The longitudinal lumen may have a diameter of at least about 1 mm, or at least about 2 mm, or at least about 3 mm.

[0064] The longitudinal lumen may be up to about 8 mm, or up to about 7 mm, or up to about 6.5 mm in diameter.

[0065] For example, the longitudinal lumen may have a diameter between about 1 mm and about 8 mm, or between about 2 mm and about 7 mm, or between about 3 mm and about 6.5 mm.

[0066] The longitudinal lumen may have a diameter of approximately 6 mm.

[0067] The diameter of the longitudinal cavity can be selected so that the volume of the cavity is large enough that it provides the desired level of airflow, while also maintaining sufficient wall thickness. This is necessary so that a sufficient amount of tobacco material is provided within the hollow tubular matrix element, and so that the hollow tubular matrix element has a sufficiently high rigidity so that it can be self-supporting.

[0068] Preferably, the longitudinal lumen has a substantially constant cross-sectional shape and size along the length of the hollow tubular matrix. However, one or both of the cross-sectional shape and size of the longitudinal lumen may vary along the length of the hollow tubular matrix element.

[0069] Preferably, the longitudinal cavity has a substantially circular cross-section.Alternatively, the longitudinal cavity may have a substantially elliptical cross-section.

[0070] The longitudinal lumen may have a constant diameter along the length of the hollow tubular matrix element. However, the diameter of the longitudinal lumen may vary along the length of the hollow tubular matrix element.

[0071] As discussed above, the hollow tubular matrix element comprises a plurality of perforations, and the plurality of perforations provide fluid communication between the longitudinal cavity of the hollow tubular matrix element and at least a portion of the outer surface of the hollow tubular matrix element and the empty space between the outer packaging. A plurality of perforations are formed through the peripheral wall of the hollow tubular matrix element. A plurality of perforations are provided so that when the consumer generates the article by aerosol suction, aerosol is generated from the outer portion of the hollow tubular matrix element and is released into the empty space to be sucked into the longitudinal cavity of the hollow tubular matrix element. A plurality of perforations are provided to increase the turbulence level in the longitudinal cavity of the hollow tubular matrix element. This can strengthen air and the aerosol released from the hollow tubular matrix element to form the mixing of components, thereby improving aerosol generation.

[0072] Preferably, the plurality of perforations are arranged in one or more rows extending circumferentially around the hollow tubular matrix element. In other words, the hollow tubular matrix element preferably comprises one or more rows of perforations extending circumferentially around the hollow tubular matrix element.

[0073] The hollow tubular matrix element may include at least two rows of perforations extending circumferentially around the hollow tubular matrix element.

[0074] The hollow tubular matrix element may include up to five rows of perforations extending circumferentially around the hollow tubular matrix element.

[0075] The circumferential rows of perforations may follow various patterns. For example, the circumferential rows of perforations may be arranged circularly or spirally around the hollow tubular matrix element.

[0076] Preferably, each row of circumferential perforations comprises between 8 and 30 perforations.

[0077] The plurality of perforations may be formed using suitable known methods, for example in-line during manufacture of the aerosol-generating article.

[0078] The plurality of perforations may include at least one perforation having a maximum dimension of at least 200 microns, or at least 300 microns, or at least about 400 microns, or at least about 500 microns.

[0079] Where the perforations are substantially circular, the maximum dimension of the perforations is the diameter of the perforations. The plurality of perforations may include at least one perforation having a maximum dimension of up to about 1 mm, or up to about 900 microns, or up to about 800 microns, or up to about 700 microns.

[0080] The plurality of perforations may include at least one perforation having a maximum dimension between about 200 microns and about 1 mm, or between about 200 microns and about 900 microns, or between about 200 microns and 800 microns, or between about 200 microns and about 700 microns.

[0081] The plurality of perforations may include at least one perforation having a maximum dimension between about 300 microns and about 1 mm, or between about 300 microns and about 900 microns, or between about 300 microns and 800 microns, or between about 300 microns and about 700 microns.

[0082] The plurality of perforations may include at least one perforation having a maximum dimension between about 400 microns and about 1 mm, or between about 400 microns and about 900 microns, or between about 400 microns and 800 microns, or between about 400 microns and about 700 microns.

[0083] The plurality of perforations may include at least one perforation having a maximum dimension between about 500 microns and about 1 mm, or between about 500 microns and about 900 microns, or between about 500 microns and 800 microns, or between about 500 microns and about 700 microns.

[0084] Each of the plurality of perforations may have a maximum dimension of at least 200 microns, at least 300 microns, at least 400 microns, or at least 500 microns.

[0085] Each of the plurality of perforations may have a maximum dimension of up to about 1 mm, or up to about 900 microns, or up to about 800 microns, or up to about 700 microns.

[0086] Each of the plurality of perforations may have a maximum dimension between about 200 microns and about 1 mm, or between about 200 microns and about 900 microns, or between about 200 microns and 800 microns, or between about 200 microns and about 700 microns.

[0087] Each of the plurality of perforations may have a maximum dimension between about 300 microns and about 1 mm, or between about 300 microns and about 900 microns, or between about 300 microns and 800 microns, or between about 300 microns and about 700 microns.

[0088] Each of the plurality of perforations may have a maximum dimension between about 400 microns and about 1 mm, or between about 400 microns and about 900 microns, or between about 400 microns and 800 microns, or between about 400 microns and about 700 microns.

[0089] Each of the plurality of perforations may have a maximum dimension between about 500 microns and about 1 mm, or between about 500 microns and about 900 microns, or between about 500 microns and 800 microns, or between about 500 microns and about 700 microns.

[0090] The plurality of perforations may include at least one perforation having an open area of ​​at least about 0.01 square millimeters, or at least about 0.03 square millimeters, or at least about 0.05 square millimeters, or at least about 0.07 square millimeters.

[0091] The plurality of perforations may include at least one perforation having an opening area of ​​no more than 1 square millimeter, or no more than 0.8 square millimeter, or no more than 0.5 square millimeter, or no more than 0.3 square millimeter, or no more than 0.1 square millimeter.

[0092] The plurality of perforations may include at least one perforation having an opening area between about 0.01 square millimeters to about 1 square millimeter, or between about 0.01 square millimeters to about 0.8 square millimeters, or between about 0.01 square millimeters to about 0.5 square millimeters, or between about 0.01 square millimeters to about 0.3 square millimeters, or between about 0.01 square millimeters to about 0.1 square millimeters.

[0093] The plurality of perforations may include at least one perforation having an opening area between about 0.03 square millimeters to about 1 square millimeter, or between about 0.03 square millimeters to about 0.8 square millimeters, or between about 0.03 square millimeters to about 0.5 square millimeters, or between about 0.03 square millimeters to about 0.3 square millimeters, or between about 0.03 square millimeters to about 0.1 square millimeters.

[0094] The plurality of perforations may include at least one perforation having an opening area between about 0.05 square millimeters to about 1 square millimeter, or between about 0.05 square millimeters to about 0.8 square millimeters, or between about 0.05 square millimeters to about 0.5 square millimeters, or between about 0.05 square millimeters to about 0.3 square millimeters, or between about 0.05 square millimeters to about 0.1 square millimeters.

[0095] The plurality of perforations may include at least one perforation having an opening area between about 0.07 square millimeters to about 1 square millimeter, or between about 0.07 square millimeters to about 0.8 square millimeters, or between about 0.07 square millimeters to about 0.5 square millimeters, or between about 0.07 square millimeters to about 0.3 square millimeters, or between about 0.07 square millimeters to about 0.1 square millimeters.

[0096] Each of the plurality of perforations may have an open area of ​​at least about 0.01 square millimeters, or at least about 0.03 square millimeters, or at least about 0.05 square millimeters, or at least about 0.07 square millimeters.

[0097] Each of the plurality of perforations may have an opening area of ​​no more than 1 square millimeter, or no more than 0.8 square millimeter, or no more than 0.5 square millimeter, or no more than 0.3 square millimeter, or no more than 0.1 square millimeter.

[0098] Each of the plurality of perforations may have an opening area between about 0.01 square millimeters and about 1 square millimeter, or between about 0.01 square millimeters and about 0.8 square millimeters, or between about 0.01 square millimeters and about 0.5 square millimeters, or between about 0.01 square millimeters and about 0.3 square millimeters, or between about 0.01 square millimeters and about 0.1 square millimeters.

[0099] Each of the plurality of perforations may have an opening area between about 0.03 square millimeters and about 1 square millimeter, or between about 0.03 square millimeters and about 0.8 square millimeters, or between about 0.03 square millimeters and about 0.5 square millimeters, or between about 0.03 square millimeters and about 0.3 square millimeters, or between about 0.03 square millimeters and about 0.1 square millimeters.

[0100] Each of the plurality of perforations may have an opening area between about 0.05 square millimeters and about 1 square millimeter, or between about 0.05 square millimeters and about 0.8 square millimeters, or between about 0.05 square millimeters and about 0.5 square millimeters, or between about 0.05 square millimeters and about 0.3 square millimeters, or between about 0.05 square millimeters and about 0.1 square millimeters.

[0101] Each of the plurality of perforations may have an opening area between about 0.07 square millimeters and about 1 square millimeter, or between about 0.07 square millimeters and about 0.8 square millimeters, or between about 0.07 square millimeters and about 0.5 square millimeters, or between about 0.07 square millimeters and about 0.3 square millimeters, or between about 0.07 square millimeters and about 0.1 square millimeters.

[0102] The plurality of perforations may have a total open area of ​​at least about 0.05 square millimeters, or at least about 0.2 square millimeters, or at least about 0.35 square millimeters, or at least about 0.5 square millimeters.

[0103] The plurality of perforations may have a total open area of ​​up to about 30 square millimeters, or up to about 25 square millimeters, or up to about 15 square millimeters, or up to about 10 square millimeters, or up to about 5 square millimeters.

[0104] The plurality of perforations may have a total open area between about 0.05 square millimeters and about 30 square millimeters, or between about 0.05 square millimeters and about 25 square millimeters, or between about 0.05 square millimeters and about 15 square millimeters, or between about 0.05 square millimeters and about 10 square millimeters, or between about 0.05 square millimeters and about 5 square millimeters.

[0105] The plurality of perforations may have a total open area between about 0.05 square millimeters and about 30 square millimeters, or between about 0.05 square millimeters and about 25 square millimeters, or between about 0.05 square millimeters and about 15 square millimeters, or between about 0.05 square millimeters and about 10 square millimeters, or between about 0.05 square millimeters and about 5 square millimeters.

[0106] The plurality of perforations may have a total open area between about 0.05 square millimeters and about 30 square millimeters, or between about 0.05 square millimeters and about 25 square millimeters, or between about 0.05 square millimeters and about 15 square millimeters, or between about 0.05 square millimeters and about 10 square millimeters, or between about 0.05 square millimeters and about 5 square millimeters.

[0107] The plurality of perforations may have a total open area between about 0.05 square millimeters and about 30 square millimeters, or between about 0.05 square millimeters and about 25 square millimeters, or between about 0.05 square millimeters and about 15 square millimeters, or between about 0.05 square millimeters and about 10 square millimeters, or between about 0.05 square millimeters and about 5 square millimeters.

[0108] Preferably, both the shape and size of each of the plurality of perforations are the same. This can advantageously simplify the manufacture of the plurality of perforations.

[0109] The plurality of perforations may be substantially circular in shape. The plurality of perforations may be rectangular or square in shape.

[0110] The hollow tubular matrix elements may have a ventilation level of at least about 5%, or at least about 10%, or at least about 15%.

[0111] The hollow tubular matrix elements may have a ventilation level of up to about 60%, or up to about 45%, or up to about 30%.

[0112] As used herein with reference to the present invention, the term "ventilation level" is used to describe the volume ratio between the airflow entering the hollow tubular matrix element via the perforations through the wall of the hollow tubular matrix element and the sum of the airflow entering the hollow tubular matrix element via the upstream end of the hollow tubular matrix element and the airflow entering the hollow tubular matrix element via the perforations through the wall of the hollow tubular matrix element. A greater ventilation level can mean that a higher proportion of aerosol from the empty space is drawn into the hollow cavity.

[0113] The strip of aerosol generating substrate may include one or more projections extending across the empty space between the outer surface of the hollow tubular substrate element and the outer wrapper. The one or more projections preferably extend from the outer surface of the hollow tubular substrate element to the inner surface of the outer wrapper. Thus, the width of the one or more projections is approximately the same as the width of the empty space as measured in the radial direction. When measuring the outer diameter of the hollow tubular substrate element, the width of the one or more projections is not taken into account.

[0114] As used herein with reference to the present invention, the term "radial" is used to describe a direction determined by a line extending in a plane perpendicular to the central longitudinal axis of the aerosol-generating article and passing through the intersection of the central longitudinal axis and the perpendicular plane. Thus, as used herein with reference to the present invention, the term "radial direction" refers to a direction perpendicular to the central longitudinal axis and is used, for example, when describing an aerosol-generating article having a substantially cylindrical shape.

[0115] The overwrap may be wrapped around one or more protrusions to help anchor the hollow tubular matrix element in place and maintain empty space between the hollow tubular matrix element and the overwrap.

[0116] One or more protrusions may be integral with the hollow tubular matrix element.

[0117] One or more protrusions may be non-integral with the hollow tubular matrix element. That is, one or more protrusions may be physically distinct from the hollow tubular matrix element. One or more protrusions may be adhered or otherwise attached directly or indirectly to the outer surface of the hollow tubular matrix element.

[0118] The one or more projections may be integral with the outer wrapper. The one or more projections may be formed by folds or creases in the outer wrapper. The one or more projections may be formed by curling the outer wrapper.

[0119] One or more protrusions may be non-integral with the outer wrapper. For example, one or more protrusions may be adhered or otherwise attached to the inner surface of the outer wrapper directly or indirectly.

[0120] One or more protrusions may be formed from homogenized tobacco material. One or more protrusions may be formed from the same material as the hollow tubular matrix element. Aerosol may advantageously be generated from such protrusions and released into the empty space. This may further reduce the preheating time of the aerosol-generating article.

[0121] The one or more protrusions may be formed of a different material than the hollow tubular matrix element.

[0122] The one or more protrusions may extend the entire length of the hollow tubular matrix element. Alternatively, the one or more protrusions may not extend the entire length of the hollow tubular matrix element. The one or more protrusions may extend a portion of the length of the hollow tubular matrix element.

[0123] The one or more protrusions may be in the form of one or more disks. The disks may be inserted onto the hollow tubular matrix element. The disks may have an outer diameter that is substantially the same as the outer diameter of the aerosol generating article. The disks may have an inner diameter that is substantially the same as the outer diameter of the hollow tubular matrix element. The one or more disks may be arranged so that they do not substantially impede or prevent aerosol in the empty space from being drawn into the longitudinal cavity of the hollow tubular matrix element through the plurality of perforations of the hollow tubular matrix element.

[0124] The one or more protrusions may be arranged such that the empty space is discontinuous. That is, the empty space may include a plurality of channels defined by the one or more protrusions. The plurality of channels of the empty space may be arranged substantially longitudinally along the aerosol generating substrate. For example, the empty space may include a plurality of longitudinal channels defined by two or more protrusions extending the entire length of the hollow tubular substrate element.

[0125] Where the aerosol-generating substrate comprises a plurality of protrusions, the plurality of protrusions may be substantially equally spaced around the hollow tubular substrate element.

[0126] The empty space may be an annular empty space.

[0127] The empty space may have a circular cross-section.

[0128] The empty space may be annular along the entire length of the hollow tubular matrix element. That is, the empty space may have an annular cross-section along the entire length of the hollow tubular matrix element.

[0129] The aerosol generating substrate may include an upstream element adjacent to the upstream end of the hollow tubular substrate element. By providing the upstream element, the hollow tubular substrate element may be more protected than a hollow tubular substrate element without the upstream element upstream of the hollow tubular substrate element. The upstream element may also help define the empty space between the hollow tubular substrate element and the outer packaging. The upstream element may be sized and positioned so that the empty space does not extend to the upstream end of the aerosol generating article or the aerosol generating substrate.

[0130] The upstream element may abut the upstream end of the hollow tubular matrix element.The upstream element may be attached to the hollow tubular matrix element.

[0131] The upstream element may be located at the upstream end of the aerosol-generating substrate.The upstream element may be located at the upstream end of the aerosol-generating article.

[0132] The outer wrapper may define the hollow tubular matrix element and at least a portion of the upstream element. The outer wrapper may define the entire length of the upstream element.

[0133] The upstream element may be an upstream rod element. For example, the upstream element may be a cellulose acetate tow rod.

[0134] Preferably, the outer diameter of the upstream element is substantially the same as the outer diameter of the aerosol-generating substrate.Preferably, the outer diameter of the upstream element is substantially the same as the outer diameter of the aerosol-generating article.

[0135] The outer diameter of the upstream element may be at least about 5 mm, or at least about 5.5 mm, or at least about 6 mm.

[0136] The outer diameter of the upstream element may be up to about 10 mm, or up to about 9 mm, or up to about 8 mm.

[0137] For example, the outer diameter of the upstream element may be between about 5 mm and about 10 mm, or between about 5.5 mm and about 9 mm, or between about 6 mm and about 8 mm.

[0138] The outer diameter of the upstream element may be greater than the outer diameter of at least a portion of the hollow tubular matrix element. This may allow a void space to be defined between the outer surface of the hollow tubular matrix element and an outer wrapper defining the hollow tubular matrix element and at least a portion of the upstream element.

[0139] Preferably, at least a portion of the hollow tubular matrix element has an outer diameter that is at least about 0.1 mm smaller than the outer diameter of the upstream element, or at least about 0.2 mm smaller than the outer diameter of the upstream element.

[0140] Preferably, at least a portion of the hollow tubular matrix element has an outer diameter up to about 6 mm smaller than the outer diameter of the upstream element, up to about 4.5 mm smaller than the outer diameter of the upstream element, or up to 3 mm smaller than the outer diameter of the upstream element.

[0141] For example, the outer diameter of at least a portion of the hollow tubular matrix element can be between about 0.1 mm and about 6 mm smaller than the outer diameter of the upstream element, or between about 0.2 mm and about 3 mm smaller than the outer diameter of the upstream element.

[0142] The outer diameter of at least a portion of the hollow tubular matrix element may be about 0.2 mm smaller than the outer diameter of the upstream element.

[0143] The difference between the outer diameter of the hollow tubular matrix element and the outer diameter of the upstream element can define the size of the empty space. In particular, the difference between the outer diameter of the hollow tubular matrix element and the outer diameter of the upstream element can be equal to twice the spacing of the empty space across the outer surface of the hollow tubular matrix element and the outer wrapper. Thus, the difference between the outer diameter of the hollow tubular matrix element and the outer diameter of the upstream element can be selected based on the desired size of the empty space.

[0144] The upstream element may have a length of at least about 2 mm, or at least about 3 mm, or at least about 5 mm.

[0145] The upstream element may have a length of up to about 15 mm, or up to about 12 mm, or up to about 10 mm.

[0146] For example, the upstream element may have a length of between about 2 mm and about 15 mm, or between about 3 mm and about 12 mm, or between about 5 mm and about 10 mm.

[0147] The upstream element may have a length of approximately 5 mm.

[0148] The length of the upstream element may be selected based on the position of the external heating element in the corresponding aerosol generating device to align the hollow tubular substrate element with the external heating element when the aerosol generating article is fully inserted into the aerosol generating device.

[0149] The aerosol-generating substrate may include a downstream element adjacent to the downstream end of the hollow tubular substrate element. The downstream element may abut the downstream end of the hollow tubular substrate element. The downstream element may be attached to the hollow tubular substrate element.

[0150] The downstream element may be located at the downstream end of the aerosol-generating substrate.The downstream element may be adjacent to a downstream section of the aerosol-generating article.

[0151] The outer wrapper may define the hollow tubular matrix element and at least a portion of the downstream element.The outer wrapper may define the entire length of the downstream element.

[0152] The characteristics of the upstream element discussed above may also apply to the downstream element. For example, at least one of the shape, size and material of the upstream element described above may apply to the downstream element. The downstream element may be the same as the upstream element.

[0153] The downstream element may be a downstream rod element. For example, the downstream element may be a cellulose acetate tow rod.

[0154] Preferably, the outer diameter of the downstream element is substantially the same as the outer diameter of the aerosol-generating substrate. Preferably, the outer diameter of the downstream element is substantially the same as the outer diameter of the aerosol-generating article. Preferably, the outer diameter of the downstream element is substantially the same as the outer diameter of the upstream element. More preferably, the outer diameter of the downstream element is substantially the same as the outer diameter of the upstream element and the outer diameter of the aerosol-generating article. This may help ensure that the outer diameter of the aerosol-generating article is substantially constant along the length of the aerosol-generating article.

[0155] The outer diameter of the downstream element may be at least about 5 mm, or at least about 5.5 mm, or at least about 6 mm.

[0156] The outer diameter of the downstream element may be up to about 10 mm, or up to about 9 mm, or up to about 8 mm.

[0157] For example, the outer diameter of the downstream element may be between about 5 mm and about 10 mm, or between about 5.5 mm and about 9 mm, or between about 6 mm and about 8 mm.

[0158] The outer diameter of the downstream element may be greater than the outer diameter of at least a portion of the hollow tubular matrix element. This may allow a void space to be defined between the outer surface of the hollow tubular matrix element and an outer wrapper defining the hollow tubular matrix element and at least a portion of the downstream element.

[0159] Preferably, at least a portion of the hollow tubular matrix element has an outer diameter that is at least about 0.1 mm smaller than the outer diameter of the downstream element, or at least about 0.2 mm smaller than the outer diameter of the downstream element.

[0160] Preferably, at least a portion of the hollow tubular matrix element has an outer diameter up to about 6 mm smaller than the outer diameter of the downstream element, up to about 4.5 mm smaller than the outer diameter of the downstream element, or up to 3 mm smaller than the outer diameter of the downstream element.

[0161] For example, the outer diameter of at least a portion of the hollow tubular matrix element can be between about 0.1 mm and about 6 mm smaller than the outer diameter of the downstream element, or between about 0.2 mm and about 3 mm smaller than the outer diameter of the downstream element.

[0162] The outer diameter of at least a portion of the hollow tubular matrix element may be about 0.2 mm smaller than the outer diameter of the downstream element.

[0163] The difference between the outer diameter of the hollow tubular matrix element and the outer diameter of the downstream element can define the size of the empty space. In particular, the difference between the outer diameter of the hollow tubular matrix element and the outer diameter of the downstream element can be equal to twice the spacing of the empty space across the outer surface of the hollow tubular matrix element and the outer wrapper. Thus, the difference between the outer diameter of the hollow tubular matrix element and the outer diameter of the downstream element can be selected based on the desired size of the empty space.

[0164] The downstream element may have a length of at least about 2 mm, or at least about 3 mm, or at least about 5 mm.

[0165] The downstream element may have a length of up to about 15 mm, or up to about 12 mm, or up to about 10 mm.

[0166] For example, the downstream element may have a length between about 2 mm and about 15 mm, or between about 3 mm and about 12 mm, or between about 5 mm and about 10 mm.

[0167] The downstream element may have a length of approximately 5 mm.

[0168] The central longitudinal axis of the hollow tubular matrix element is preferably aligned with the central longitudinal axis of other elements of the aerosol-generating article (e.g., other components of the aerosol-generating substrate and components of the downstream section). For example, the central longitudinal axis of the hollow tubular matrix element is preferably aligned with the central longitudinal axis of both the upstream element and the downstream element. The central longitudinal axis of the hollow tubular matrix element is preferably aligned with the central longitudinal axis of the aerosol-generating article.

[0169] In the case where the hollow tubular matrix element is in abutting arrangement with both the upstream element and the downstream element, the hollow tubular matrix element can be supported between the upstream element and the downstream element. The outer packaging material can be tightly wrapped around one or both of the upstream element and the downstream element to hold the upstream element, the hollow tubular matrix element and the downstream element in place.

[0170] The overwrap may not be attached to the hollow tubular matrix element.

[0171] The overwrap may be attached to one or both of the upstream and downstream elements.

[0172] The upstream element, the hollow tubular matrix element, and the downstream element may be attached to each other. This may also help to keep the upstream element, the hollow tubular matrix element, and the downstream element in place.

[0173] Within the void space, the outer surface of the hollow tubular matrix element and the outer wrapper may be separated in the radial direction by at least about 0.05 mm, or separated in the radial direction by at least about 0.1 mm.

[0174] Within the void space, the outer surface of the hollow tubular matrix element and the outer wrapper may be separated in the radial direction by up to about 3 mm, separated in the radial direction by up to about 2.25 mm, or separated in the radial direction by up to about 1.5 mm.

[0175] For example, within the void space, the outer surface of the hollow tubular matrix element and the outer wrapper may be separated in the radial direction by about 0.05 mm and about 3 mm, or by about 0.1 mm and about 1.5 mm.

[0176] Within the void space, the outer surface of the hollow tubular matrix element and the outer wrapper may be separated in the radial direction by about 0.1 mm.

[0177] As described above, the outer wrapper can define the hollow tubular matrix element and at least a portion of both the upstream element and the downstream element to define a blank space between the outer wrapper and the hollow tubular matrix element. In other words, the blank space can be defined by the outer surface of the hollow tubular matrix element, the portion of the outer wrapper that defines the hollow tubular matrix element, the downstream end face of the upstream element, and the upstream end face of the downstream element. Thus, providing both the upstream element and the downstream element can provide an effective way to create a blank space without the need for additional elements.

[0178] Preferably, the outer wrapper has enough structural rigidity so that the empty space can remain between the outer wrapper and the hollow tubular matrix element.For example, the outer wrapper can have enough structural rigidity so that the outer wrapper can not collapse at the hollow tubular matrix element during the processing or storage of the aerosol-generating goods.Yet some flexibility in the outer wrapper may be desirable so that when the consumer generates the goods by aerosol suction air, the outer wrapper can be sucked to the outer surface of the hollow tubular matrix element.This can contribute to forcing the aerosol in the empty space to enter in the longitudinal cavity.The basis weight of the outer wrapper can be selected to make the outer wrapper have the balance of expectation between structural rigidity and flexibility.

[0179] The overwrap may have a basis weight of at least about 15 g / m2, or at least about 20 g / m2, or at least about 25 g / m2.

[0180] The overwrap may have a basis weight of up to about 100 g / m2, or up to about 90 g / m2, or up to about 80 g / m2, or up to 50 g / m2.

[0181] In some embodiments, the overwrap is preferably rigid, for example, the overwrap may have a basis weight of at least about 80 grams per square meter (gsm), or at least about 100 gsm, or at least about 110 gsm.

[0182] The outer wrapper may include a plurality of perforations overlying the hollow tubular matrix element. This may enable air to be drawn into the empty space, which may increase the level of turbulence in the empty space.

[0183] Any wrapper defining the hollow tubular matrix element may include a plurality of perforations that are substantially aligned with the plurality of perforations of the outer wrapper.

[0184] Preferably, the plurality of perforations of the outer wrapper are arranged in one or more circumferential rows. That is, the outer wrapper may comprise one or more rows of circumferential perforations.

[0185] The outer wrapper may comprise at least two rows of circumferential perforations.

[0186] The outer wrapper may include up to five rows of circumferential perforations.

[0187] The circumferential rows of perforations may follow various patterns. For example, the circumferential rows of perforations may be arranged circularly or spirally around the hollow tubular matrix element.

[0188] Preferably, each row of circumferential perforations comprises between 8 and 30 perforations.

[0189] The properties of the plurality of perforations of the hollow tubular matrix element discussed above can also be applied to the plurality of perforations of the outer wrapper. For example, the outer wrapper can have the same number of rows of perforations and the same number of perforations per row as the hollow tubular matrix element.

[0190] The plurality of perforations of the overwrap may include at least one perforation having a maximum dimension of at least 200 microns, or at least 300 microns, or at least about 400 microns, or at least about 500 microns.

[0191] In the case where the perforation of the outer wrapper is substantially circular, the maximum dimension of the perforation is the diameter of the perforation. A plurality of perforations of the outer wrapper may comprise at least one perforation having a maximum dimension of up to about 1 millimeter, or up to about 900 microns, or up to about 800 microns, or up to about 700 microns.

[0192] Each of the plurality of perforations of the outer wrapper may have a maximum dimension of at least 200 microns, at least 300 microns, at least 400 microns, or at least 500 microns.

[0193] Each of the plurality of perforations of the outer wrapper may have a maximum dimension of up to about 1 mm, or up to about 900 microns, or up to about 800 microns, or up to about 700 microns.

[0194] The plurality of perforations of the outer wrapper may include at least one perforation having an opening area of ​​at least about 0.01 square millimeters, or at least about 0.03 square millimeters, or at least about 0.05 square millimeters, or at least about 0.07 square millimeters.

[0195] The plurality of perforations of the outer wrapper may include at least one perforation having an opening area of ​​no more than 1 square millimeter, or no more than 0.8 square millimeter, or no more than 0.5 square millimeter, or no more than 0.3 square millimeter, or no more than 0.1 square millimeter.

[0196] Each of the plurality of perforations of the outer wrapper may have an open area of ​​at least about 0.01 square millimeters, or at least about 0.03 square millimeters, or at least about 0.05 square millimeters, or at least about 0.07 square millimeters.

[0197] Each of the plurality of perforations of the outer wrapper may have an opening area of ​​no more than 1 square millimeter, or no more than 0.8 square millimeter, or no more than 0.5 square millimeter, or no more than 0.3 square millimeter, or no more than 0.1 square millimeter.

[0198] The plurality of perforations of the outer wrapper may have a total open area of ​​at least about 0.05 square millimeters, or at least about 0.2 square millimeters, or at least about 0.35 square millimeters, or at least about 0.5 square millimeters.

[0199] The plurality of perforations of the outer wrapper may have a total open area of ​​up to about 30 square millimeters, or up to about 25 square millimeters, or up to about 15 square millimeters, or up to about 10 square millimeters, or up to about 5 square millimeters.

[0200] The plurality of perforations of the outer wrapper may overlie the empty space.

[0201] Preferably, the plurality of perforations of the outer wrapper overlie the plurality of perforations of the hollow tubular matrix element. That is, preferably, the plurality of perforations of the outer wrapper are substantially aligned with the plurality of perforations of the hollow tubular matrix element. This can allow the aerosol generating article to have a desired RTD. This can also simplify the manufacture of the aerosol generating article, because the plurality of perforations of the outer wrapper and the plurality of perforations of the hollow tubular matrix element can be formed simultaneously after the hollow tubular matrix element is defined by the outer wrapper.

[0202] The plurality of perforations may be formed using suitable known methods, for example in-line during manufacture of the aerosol-generating article.

[0203] Preferably, the outer wrapper is non-porous so that the airflow into the aerosol-generating article can be controlled. For example, a non-porous outer wrapper can prevent air from passing through the outer wrapper into upstream and downstream components.

[0204] The rod of aerosol-generating substrate may comprise one or more susceptor elements positioned in contact with the hollow tubular substrate element for inductively heating the homogenised tobacco material during use.

[0205] As used herein, the term "susceptor element" refers to an element comprising a material capable of converting electromagnetic energy into heat. When the susceptor element is located in an alternating electromagnetic field, the susceptor is heated. The heating of the susceptor element may be the result of at least one of hysteresis losses and eddy currents induced in the susceptor, depending on the electrical and magnetic properties of the susceptor material.

[0206] Preferably, the strip of aerosol-generating substrate comprises one or more susceptor elements located on the surface of the hollow tubular substrate element. The hollow tubular substrate element may comprise one or more susceptor elements located on the inner surface of the hollow tubular substrate element. Alternatively or additionally, the strip of aerosol-generating substrate may comprise one or more susceptor elements located on the outer surface of the hollow tubular substrate element.

[0207] The one or more susceptor elements may be positioned remote from the plurality of perforations of the hollow tubular matrix element such that air and aerosol may flow from the empty space to the hollow cavity through the plurality of perforations of the hollow tubular matrix element.

[0208] One or more susceptor elements may include a plurality of perforations. Preferably, the plurality of perforations of the one or more susceptor elements are arranged to substantially overlap with the plurality of perforations of the hollow tubular matrix element. That is, preferably, the plurality of perforations of the one or more susceptor elements are substantially aligned with the plurality of perforations of the hollow tubular matrix element. This can allow air and aerosol to flow from the empty space to the hollow cavity through the plurality of perforations of the hollow tubular matrix element and through the plurality of perforations of the one or more susceptor elements. For example, the one or more susceptor elements may be in the form of one or more perforated sheets.

[0209] One or more susceptor elements may be embedded within the wall of the hollow tubular matrix element.

[0210] The susceptor element may comprise any suitable material. The susceptor element may be formed of any material that can be inductively heated to a temperature sufficient to release volatile compounds from the aerosol generating substrate. Suitable materials for the elongated susceptor element include graphite, molybdenum, silicon carbide, stainless steel, niobium, aluminum, nickel, nickel-containing compounds, titanium, and metal material composites. Some susceptor elements include metal or carbon. Advantageously, the susceptor element may include or consist of a ferromagnetic material, such as ferritic iron, ferromagnetic alloys (e.g., ferromagnetic steel or stainless steel), ferromagnetic particles, and ferrites. Suitable susceptor elements may be aluminum or include aluminum. The susceptor element preferably comprises greater than about 5%, preferably greater than about 20%, more preferably greater than about 50%, or greater than about 90% ferromagnetic or paramagnetic material. Some elongated susceptor elements may be heated to a temperature exceeding about 250 degrees Celsius.

[0211] The aerosol-generating substrate may have a length of at least about 10 mm, at least about 12 mm, or at least about 15 mm.

[0212] The aerosol-generating substrate may have a length of up to about 40 mm, up to about 37 mm or up to about 35 mm.

[0213] For example, the aerosol-generating substrate may have a length of between about 10 mm and about 40 mm, or between about 12 mm and about 37 mm, or between about 15 mm and about 35 mm.

[0214] The aerosol-generating substrate may have a length that is greater than the length of the hollow tubular substrate element.

[0215] As described above, in the aerosol-generating article of the present invention, the aerosol-generating substrate comprising a hollow tubular substrate element is combined with a downstream section located downstream of the aerosol-generating substrate. Preferably, the downstream section is located immediately downstream of the aerosol-generating substrate. Preferably, the downstream section of the aerosol-generating article extends between the aerosol-generating substrate and the downstream end of the aerosol-generating article. The downstream section may include one or more elements, each of which will be described in more detail within the present disclosure.

[0216] Preferably, the downstream section comprises at least one hollow tubular element. The hollow tubular element may be adjacent to the downstream end of the strip of aerosol-generating substrate. The hollow tubular element may be arranged immediately downstream of the aerosol-generating substrate. In other words, the hollow tubular element may abut the downstream end of the aerosol-generating substrate. This arrangement may optimize the flow of aerosol from the longitudinal airflow channel of the hollow tubular substrate element into the downstream section and through the aerosol-generating article.

[0217] Preferably, the downstream section of the aerosol-generating article comprises a single hollow tubular element. In other words, the downstream section of the aerosol-generating article may comprise only one hollow tubular element.

[0218] The hollow tubular element of the downstream section may also be referred to as hollow tubular downstream element.

[0219] In the context of the present invention, the hollow tubular element of the downstream section provides an unrestricted flow passage through the air flow passage. This means that the hollow tubular element provides a negligible level of resistance to draw (RTD) as defined above. Therefore, the air flow passage should be free of any components that hinder the flow of air in the longitudinal direction. Preferably, the air flow passage is substantially empty.

[0220] The hollow tubular element of the downstream section provides a cavity downstream of the aerosol-generating substrate, which can enhance the cooling and nucleation of aerosol particles generated by the aerosol-generating substrate. Therefore, the hollow tubular element of the downstream section can serve as an aerosol-cooling element.

[0221] The length of the hollow tubular element may be at least about 12 mm. The length of the hollow tubular element may be at least about 15 mm. The length of the hollow tubular element may be at least about 20 mm.

[0222] The length of the hollow tubular element of the downstream section may be less than or equal to about 50 mm. The length of the hollow tubular element may be less than or equal to about 45 mm. The length of the hollow tubular element may be less than or equal to about 40 mm.

[0223] For example, the length of the hollow tubular element of the downstream section may be between about 12 mm and 50 mm. The length of the hollow tubular element may be between about 15 mm and 45 mm. The length of the hollow tubular element may be between about 20 mm and 40 mm. The length of the hollow tubular element may be about 30 mm.

[0224] A relatively long hollow tubular element is provided within the downstream section of the aerosol-generating article and defines a relatively long internal cavity.Providing a relatively long cavity can maximize the above-mentioned nucleation benefits, thereby improving aerosol formation and cooling.

[0225] The ratio between the length of the hollow tubular matrix element and the length of the hollow tubular element of the downstream section may be less than or equal to about 1.25. Preferably, the ratio between the length of the hollow tubular matrix element and the length of the hollow tubular element of the downstream section may be less than or equal to about 1. More preferably, the ratio between the length of the hollow tubular matrix element and the length of the hollow tubular element of the downstream section may be less than or equal to about 0.75.

[0226] The ratio between the length of the hollow tubular matrix element and the length of the hollow tubular element of the downstream section may be at least about 0.2. Preferably, the ratio between the length of the hollow tubular matrix element and the length of the hollow tubular element of the downstream section may be at least about 0.25. More preferably, the ratio between the length of the hollow tubular matrix element and the length of the hollow tubular element of the downstream section may be at least about 0.3.

[0227] For example, the ratio between the length of the hollow tubular matrix element and the length of the hollow tubular element of the downstream segment may be between about 0.2 and about 1.25, or between about 0.25 and about 1, or between about 0.3 and about 0.75.

[0228] The ratio between the length of the hollow tubular element of the downstream section and the total length of the downstream section may be less than or equal to about 1. Preferably, the ratio between the length of the hollow tubular element of the downstream section and the total length of the downstream section may be less than or equal to about 0.90. More preferably, the ratio between the length of the hollow tubular element of the downstream section and the total length of the downstream section may be less than or equal to about 0.85.

[0229] The ratio between the length of the hollow tubular element of the downstream section and the total length of the downstream section may be at least about 0.35. Preferably, the ratio between the length of the hollow tubular element of the downstream section and the total length of the downstream section may be at least about 0.45. More preferably, the ratio between the length of the hollow tubular element of the downstream section and the total length of the downstream section may be at least about 0.50.

[0230] For example, the ratio between the length of the hollow tubular element of the downstream section and the total length of the downstream section may be between about 0.35 and about 1, or between about 0.45 and about 0.9, or between about 0.5 and about 0.85.

[0231] The ratio between the length of the hollow tubular element of the downstream section and the overall length of the aerosol-generating article may be less than or equal to about 0.80. Preferably, the ratio between the length of the hollow tubular element of the downstream section and the overall length of the aerosol-generating article may be less than or equal to about 0.70. More preferably, the ratio between the length of the hollow tubular element of the downstream section and the overall length of the aerosol-generating article may be less than or equal to about 0.60.

[0232] The ratio between the length of the hollow tubular element of the downstream section and the overall length of the aerosol-generating article may be at least about 0.25. Preferably, the ratio between the length of the hollow tubular element of the downstream section and the overall length of the aerosol-generating article may be at least about 0.30. More preferably, the ratio between the length of the hollow tubular element of the downstream section and the overall length of the aerosol-generating article may be at least about 0.40.

[0233] For example, the ratio between the length of the hollow tubular element of the downstream section and the overall length of the aerosol-generating article may be between about 0.25 and about 0.8, or between about 0.3 and about 0.7, or between about 0.4 and about 0.6.

[0234] The wall thickness of the hollow tubular element of the downstream section may be at least about 100 microns. The wall thickness of the hollow tubular element of the downstream section may be at least about 150 microns. The wall thickness of the hollow tubular element of the downstream section may be at least about 200 microns, preferably at least about 250 microns and even more preferably at least about 500 microns (or 0.5 mm).

[0235] The wall thickness of the hollow tubular element of the downstream section may be less than or equal to about 2 mm, preferably less than or equal to about 1.5 mm and even more preferably less than or equal to about 1.25 mm. The wall thickness of the hollow tubular element of the downstream section may be less than or equal to about 1 mm. The wall thickness of the hollow tubular element of the downstream section may be less than or equal to about 500 microns.

[0236] The wall thickness of the hollow tubular element of the downstream section may be between about 100 micrometers and about 2 millimeters, preferably between about 150 micrometers and about 1.5 millimeters, even more preferably between about 200 micrometers and about 1.25 millimeters.

[0237] Keeping the wall thickness of the hollow tubular segment of the downstream section relatively low ensures that the overall internal volume of the hollow tubular element (which allows the aerosol to begin the nucleation process once the aerosol components leave the aerosol generating substrate) and the cross-sectional surface area of ​​the cavity of the hollow tubular element is effectively maximized, while ensuring that the hollow tubular element has the necessary structural strength to prevent collapse of the aerosol generating article and provide some support for the strip of aerosol generating substrate, and the RTD of the hollow tubular element is minimized. Larger values ​​of the cross-sectional surface area of ​​the cavity of the hollow tubular element should be understood to be associated with a reduced velocity of the aerosol flow traveling along the aerosol generating article, which is also expected to be beneficial to aerosol nucleation. In addition, it seems that by utilizing a hollow tubular element with a relatively low thickness, the ventilation air can be substantially prevented from diffusing before it contacts and mixes with the aerosol flow, which is also understood to further facilitate the nucleation phenomenon. In fact, by providing more controlled local cooling of the volatile substance flow, it is possible to enhance the effect of cooling on the formation of new aerosol particles.

[0238] The outer diameter of the hollow tubular element of the downstream section is preferably substantially equal to the outer diameter of the aerosol-generating substrate and the outer diameter of the aerosol-generating article.The outer diameter of the hollow tubular element of the downstream section is preferably greater than the outer diameter of the hollow tubular substrate element of the aerosol-generating substrate.

[0239] The outer diameter of the hollow tubular element may be between 5 and 10 mm, such as between 5.5 and 9 mm, or between 6 and 8 mm.

[0240] The hollow tubular element of the downstream section may have a constant inner diameter along the length of the hollow tubular element.However, the inner diameter of the hollow tubular element may vary along the length of the hollow tubular element.

[0241] The hollow tubular element of the downstream section may have an inner diameter of at least about 2 mm. For example, the hollow tubular element may have an inner diameter of at least about 2.5 mm, at least about 3 mm, or at least about 3.5 mm. Providing a hollow tubular element with an inner diameter as described above can advantageously provide the hollow tubular element with sufficient rigidity and strength.

[0242] The hollow tubular element of the downstream section may have an inner diameter of no more than about 10 mm. For example, the hollow tubular element may have an inner diameter of no more than about 9 mm, no more than about 8 mm, or no more than about 7.5 mm. Providing a hollow tubular element having an inner diameter as described above can advantageously reduce the suction resistance of the hollow tubular segment.

[0243] For example, the hollow tubular element of the downstream section may have an inner diameter between about 2 mm and about 10 mm, between about 2.5 mm and about 9 mm, between about 3 mm and about 8 mm, or between about 3.5 mm and about 7.5 mm.

[0244] The ratio of the inner diameter of the hollow tubular matrix element to the inner diameter of the hollow tubular element of the downstream section is preferably between about 0.8 and about 1.2, more preferably between about 0.9 and about 1.1, and most preferably about 1.

[0245] Particularly preferably, the inner diameter of the hollow tubular matrix element is substantially equal to the inner diameter of the hollow tubular element of the downstream section.

[0246] The central longitudinal axis of the hollow tubular matrix element of the aerosol-generating substrate may preferably be aligned with the central longitudinal axis of the hollow tubular element of the downstream segment. For example, in the case where the inner diameter of the hollow tubular matrix element is substantially equal to the inner diameter of the hollow tubular element of the downstream segment, the central longitudinal axis of the hollow tubular matrix element may be aligned with the central longitudinal axis of the hollow tubular matrix element of the downstream segment, such that the lumen of the hollow tubular matrix element and the lumen of the hollow tubular element of the downstream segment may be substantially aligned.

[0247] The hollow tubular element of the downstream section may comprise a paper-based material. The hollow tubular element may comprise at least one paper layer. The paper may be a very hard paper. The paper may be a curled paper, such as a curled heat-resistant paper or a curled parchment paper.

[0248] Preferably, the hollow tubular element may comprise cardboard. The hollow tubular element may be a cardboard tube. The hollow tubular element may be formed from cardboard. Advantageously, cardboard is a cost-effective material that provides a balance between being deformable so as to provide ease of insertion of the aerosol-generating article into the aerosol-generating device and being sufficiently rigid to provide appropriate engagement of the article with the interior of the device. Thus, the cardboard tube may provide suitable resistance to deformation or compression during use.

[0249] The hollow tubular element of the downstream section can be a paper tube. The hollow tubular element can be a tube formed by spirally wound paper. The hollow tubular element can be formed from multiple paper layers. The paper can 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.

[0250] The hollow tubular element of the downstream section may include a polymer material. For example, the hollow tubular element may include a polymer film. The polymer film may include a cellulose film. The hollow tubular segment may include low density polyethylene (LDPE) or polyhydroxyalkanoate (PHA) fibers. The hollow tube may contain cellulose acetate tow.

[0251] Where the hollow tubular element comprises cellulose acetate tow, the cellulose acetate tow may have a denier per filament of between about 2 and about 4 and a total denier of between about 25 and about 40.

[0252] The hollow tubular element may be located at the upstream end of the downstream section.The hollow tubular element may abut the downstream end of the aerosol-generating substrate.The hollow tubular element may abut the downstream end of the hollow tubular substrate element.

[0253] The outer wrapper of the aerosol-generating substrate may also define at least a portion of the downstream section of the aerosol-generating article. For example, the outer wrapper of the aerosol-generating substrate may also define at least a portion of the hollow tubular element of the downstream section.

[0254] Aerosol-generating articles according to the invention may comprise a ventilation zone located at a position along the downstream section. In more detail, where the downstream section comprises a hollow tubular element, the ventilation zone may be provided at a position along the hollow tubular element.

[0255] Thus, the ventilation cavity is arranged downstream of the strip of aerosol-generating substrate. This can provide particularly effective cooling of the aerosol and promote enhanced nucleation of aerosol particles.

[0256] The ventilation zone may typically comprise a plurality of perforations through the circumferential wall of the hollow tubular element. The plurality of perforations of the ventilation zone may also pass through any packaging defining the hollow tubular element. Preferably, the ventilation zone comprises at least one row of circumferential perforations. The ventilation zone may comprise two rows of circumferential perforations. For example, the perforations may be formed on a production line during manufacture of the aerosol-generating article. Preferably, each row of circumferential perforations comprises 8 to 30 perforations.

[0257] The downstream section may further comprise a mouthpiece element. The mouthpiece element may be located at the downstream end of the aerosol-generating article. Preferably, the mouthpiece element is located downstream of the hollow tubular element of the downstream section, which is described above. The mouthpiece element may extend between the hollow tubular element of the downstream section and the downstream end of the aerosol-generating article.

[0258] Providing a mouthend element at the downstream end of an aerosol-generating article according to the invention may provide an appealing appearance and mouthfeel to the consumer.

[0259] The mouthpiece element may be a mouthpiece filter element. The mouthpiece element may include at least one mouthpiece filter segment formed of a fibrous filter material. Parameters or characteristics described with respect to the mouthpiece element as a whole may also apply to the mouthpiece filter segment of the mouthpiece element.

[0260] The fibrous filter material may be used to filter the aerosol generated by the aerosol generating substrate. Suitable fibrous filter materials will be known to the skilled person. Particularly preferably, at least one mouthpiece filter segment comprises a cellulose acetate filter segment formed from cellulose acetate tow.

[0261] The mouthpiece element may be comprised of a single mouthpiece filter segment.The mouthpiece element may comprise two or more mouthpiece filter segments axially aligned with each other in an abutting end-to-end relationship.

[0262] The downstream section may include a mouth-end cavity at the downstream end downstream of the mouthpiece element as described above. The mouth-end cavity may be defined by a further hollow tubular element disposed at the downstream end of the mouthpiece element. The mouth-end cavity may be defined by an outer wrapper of the aerosol-generating article, wherein the outer wrapper extends from (or through) the mouthpiece element in the downstream direction. For example, the mouth-end cavity may be defined by a tipping wrapper extending downstream through the mouthpiece element.

[0263] The mouthpiece element may optionally include a flavoring agent, which may be provided in any suitable form. For example, the mouthpiece element may include one or more capsules, beads or particles of a flavoring agent, or one or more threads or filaments loaded with a flavoring agent.

[0264] Preferably, the mouthpiece element or mouthpiece filter segment thereof has a low particle filtration efficiency.

[0265] Preferably, the mouthend element is defined by a rod wrap.Preferably, the mouthend element is non-ventilated, such that air does not enter the aerosol-generating article along the mouthend element.

[0266] Preferably, the mouthpiece element has an outer diameter substantially equal to the outer diameter of the aerosol generating article. The diameter of the mouthpiece element (or mouthpiece filter segment) may be substantially the same as the outer diameter of the hollow tubular element. As mentioned in the present disclosure, the outer diameter of the hollow tubular element may be about 7.2 mm ± 10%.

[0267] The diameter of the mouthpiece element may be between about 5 mm and about 10 mm. The diameter of the mouthpiece element may be between about 5.5 mm and about 9 mm. The diameter of the mouthpiece element may be between about 6 mm and about 8 mm. The diameter of the mouthpiece element may be about 7.2 mm ± 10%. The diameter of the mouthpiece element may be about 7.25 mm ± 10%.

[0268] Unless otherwise stated, the draw resistance (RTD) of a component or aerosol-generating article is measured according to ISO 6565-2015. RTD refers to the pressure required to force air through the full length of the component. The term "pressure drop" or "draw resistance" of a component or article may also refer to "resistance to draw".

[0269] The resistance to draw (RTD) of the downstream section may be at least about 0 mmH2O. The RTD of the downstream section may be at least about 3 mmH2O. The RTD of the downstream section may be at least about 6 mmH2O.

[0270] The RTD of the downstream section may be no greater than about 12 mmH2O. The RTD of the downstream section may be no greater than about 11 mmH2O. The RTD of the downstream section may be no greater than about 10 mmH2O.

[0271] The suction resistance of the downstream section may be greater than or equal to about 0 mmH2O and less than about 12 mmH2O. Preferably, the suction resistance of the downstream section may be greater than or equal to about 3 mmH2O and less than about 12 mmH2O. The suction resistance of the downstream section may be greater than or equal to about 0 mmH2O and less than about 11 mmH2O. Even more preferably, the suction resistance of the downstream section may be greater than or equal to about 3 mmH2O and less than about 11 mmH2O. Even more preferably, the suction resistance of the downstream section may be greater than or equal to about 6 mmH2O and less than about 10 mmH2O. Preferably, the suction resistance of the downstream section may be about 8 mmH2O.

[0272] The resistance to draw (RTD) characteristics of the downstream section may be entirely or primarily attributable to the RTD characteristics of the mouthpiece element of the downstream section. In other words, the RTD of the mouthpiece element of the downstream section may entirely define the RTD of the downstream section.

[0273] The resistance to draw (RTD) of the mouthpiece element may be at least about 0 mmH2O. The RTD of the mouthpiece element may be at least about 3 mmH2O. The RTD of the mouthpiece element may be at least about 6 mmH2O.

[0274] The RTD of the mouthpiece element may be no greater than about 12 mmH2O. The RTD of the mouthpiece element may be no greater than about 11 mmH2O. The RTD of the mouthpiece element may be no greater than about 10 mmH2O.

[0275] The draw resistance of the mouthpiece element may be greater than or equal to about 0 mmH2O and less than about 12 mmH2O. Preferably, the draw resistance of the mouthpiece element may be greater than or equal to about 3 mmH2O and less than about 12 mmH2O. The draw resistance of the mouthpiece element may be greater than or equal to about 0 mmH2O and less than about 11 mmH2O. Even more preferably, the draw resistance of the mouthpiece element may be greater than or equal to about 3 mmH2O and less than about 11 mmH2O. Even more preferably, the draw resistance of the mouthpiece element may be greater than or equal to about 6 mmH2O and less than about 10 mmH2O. Preferably, the draw resistance of the mouthpiece element may be about 8 mmH2O.

[0276] As described above, the mouthpiece element or the mouthpiece filter segment may be formed of a fibrous material. The mouthpiece element may be formed of a porous material. The mouthpiece element may be formed of a biodegradable material. The mouthpiece element may be formed of a cellulose material such as cellulose acetate. For example, the mouthpiece element may be formed of bundled cellulose acetate fibers having a single filament denier between about 10 and about 15. For example, the mouthpiece element is formed of a relatively low density cellulose acetate tow, such as a cellulose acetate tow comprising fibers having a single filament denier of about 12.

[0277] The mouthpiece element may be formed of a polylactic acid based material. The mouthpiece element may be formed of a bioplastic material, preferably a starch based bioplastic material. The mouthpiece element may be made by injection molding or by extrusion. Bioplastic based materials are advantageous because they can provide a mouthpiece element structure that is simple and inexpensive to manufacture, with a specific and complex cross-sectional profile that may include a plurality of relatively large airflow channels extending through the mouthpiece element material that provides suitable RTD characteristics.

[0278] The mouthpiece element may be formed from a sheet of suitable material that has been curled, pleated, gathered, woven or folded into an element defining a plurality of longitudinally extending channels. Such a sheet of suitable material may be formed from paper, paperboard, a polymer (e.g., polylactic acid), or any other cellulose-based, paper-based, or bioplastic-based material. The cross-sectional profile of such a mouthpiece element may show the channels as being randomly oriented.

[0279] The mouthpiece element may be formed in any suitable manner. For example, the mouthpiece element may be formed from a bundle of longitudinally extending tubes. The longitudinally extending tubes may be formed from polylactic acid. The mouthpiece element may be formed by extrusion, molding, lamination, injection or shredding of a suitable material. Therefore, preferably, there is a low pressure drop (or RTD) from the upstream end of the mouthpiece element to the downstream end of the mouthpiece element.

[0280] The length of the mouthpiece element may be at least about 1.5 mm. The length of the mouthpiece element may be at least about 2 mm. The length of the mouthpiece element may be equal to or less than about 7 mm. The length of the mouthpiece element may be equal to or less than about 4 mm. For example, the length of the mouthpiece element may be between about 1.5 mm and about 7 mm. The length of the mouthpiece element may be between about 2 mm and about 4 mm.

[0281] The ratio between the length of the mouthpiece element and the length of the downstream section may be less than or equal to about 0.35. Preferably, the ratio between the length of the mouthpiece element and the length of the downstream section may be less than or equal to about 0.30. More preferably, the ratio between the length of the mouthpiece element and the length of the downstream section may be less than or equal to about 0.25.

[0282] The ratio between the length of the mouthpiece element and the length of the downstream section may be at least about 0.03. Preferably, the ratio between the length of the mouthpiece element and the length of the downstream section may be at least about 0.05. More preferably, the ratio between the length of the mouthpiece element and the length of the downstream section may be at least about 0.1.

[0283] For example, the ratio between the length of the mouthend element and the length of the downstream section is from about 0.03 to about 0.35, preferably from about 0.05 to about 0.30, more preferably from about 0.1 to about 0.25.

[0284] The ratio between the length of the mouthpiece element and the overall length of the aerosol-generating article may be less than or equal to about 0.20. Preferably, the ratio between the length of the mouthpiece element and the overall length of the aerosol-generating article may be less than or equal to about 0.15. More preferably, the ratio between the length of the mouthpiece element and the overall length of the aerosol-generating article may be less than or equal to about 0.1.

[0285] The ratio between the length of the mouthpiece element and the overall length of the aerosol-generating article may be at least about 0.01. Preferably, the ratio between the length of the mouthpiece element and the overall length of the aerosol-generating article may be at least about 0.02. More preferably, the ratio between the length of the mouthpiece element and the overall length of the aerosol-generating article may be at least about 0.05.

[0286] For example, the ratio between the length of the mouthend element and the overall length of the aerosol-generating article is from about 0.01 to about 0.2, preferably from about 0.02 to about 0.15, more preferably from about 0.05 to about 0.1.

[0287] In the case where the downstream section includes a hollow tubular element and a mouthpiece element, the ratio of the length of the hollow tubular element to the length of the mouthpiece element may be at least about 1.5. In other words, the length of the hollow tubular element may be at least about 150% of the length of the mouthpiece element. The ratio of the length of the hollow tubular element to the length of the mouthpiece element may be at least about 5. The ratio of the length of the hollow tubular element to the length of the mouthpiece element may be at least about 7.5.

[0288] The ratio of the length of the hollow tubular element to the length of the mouthpiece element may be equal to or less than about 20. The ratio of the length of the hollow tubular element to the length of the mouthpiece element may be equal to or less than about 15. The ratio of the length of the hollow tubular element to the length of the mouthpiece element may be equal to or less than about 12.5.

[0289] For example, the ratio of the length of the hollow tubular element to the length of the mouthpiece element may be between about 1.5 and about 20, or between about 5 and about 15, or between about 7.5 and about 10.

[0290] The overall length of the downstream section is preferably at least about 15 mm, more preferably at least about 20 mm, and more preferably at least about 25 mm.

[0291] The overall length of the downstream section is preferably less than about 50 mm, more preferably less than about 45 mm, more preferably less than about 40 mm.

[0292] For example, the downstream section may have an overall length of between about 20 mm and about 50 mm, more preferably between about 25 mm and about 45 mm, more preferably between about 30 mm and about 40 mm.

[0293] The ratio between the total length of the downstream segment and the overall length of the aerosol-generating article may be less than or equal to about 0.80. Preferably, the ratio between the length of the downstream segment and the overall length of the aerosol-generating article may be less than or equal to about 0.75. More preferably, the ratio between the length of the downstream segment and the overall length of the aerosol-generating article may be less than or equal to about 0.70. Even more preferably, the ratio between the length of the downstream segment and the overall length of the aerosol-generating article may be less than or equal to about 0.65.

[0294] The ratio between the length of the downstream segment and the overall length of the aerosol-generating article may be at least about 0.30. Preferably, the ratio between the length of the downstream segment and the overall length of the aerosol-generating article may be at least about 0.40. More preferably, the ratio between the length of the downstream segment and the overall length of the aerosol-generating article may be at least about 0.50. Even more preferably, the ratio between the length of the downstream segment and the overall length of the aerosol-generating article may be at least about 0.60.

[0295] Preferably, the overall length of an aerosol-generating article according to the present invention is at least about 35 mm. More preferably, the overall length of an aerosol-generating article according to the present invention is at least about 40 mm. Even more preferably, the overall length of an aerosol-generating article according to the present invention is at least about 45 mm. Even more preferably, the overall length of an aerosol-generating article according to the present invention is at least about 50 mm.

[0296] The overall length of the aerosol-generating article according to the present invention is preferably less than or equal to 110 mm. More preferably, the overall length of the aerosol-generating article according to the present invention is preferably less than or equal to 100 mm. Even more preferably, the overall length of the aerosol-generating article according to the present invention is preferably less than or equal to 75 mm. Even more preferably, the overall length of the aerosol-generating article according to the present invention is preferably less than or equal to 70 mm.

[0297] For example, the overall length of the aerosol-generating article may be between about 35 mm and about 110 mm, or between about 40 mm and about 100 mm, or between about 45 mm and about 75 mm, or between about 50 mm and about 70 mm.

[0298] The aerosol-generating article preferably has an outer diameter of at least about 5 mm. Preferably, the aerosol-generating article has an outer diameter of at least 5.5 mm. More preferably, the aerosol-generating article has an outer diameter of at least 6 mm.

[0299] Preferably, the aerosol-generating article has an outer diameter of less than or equal to about 10 mm. More preferably, the aerosol-generating article has an outer diameter of less than or equal to about 9 mm. Even more preferably, the aerosol-generating article has an outer diameter of less than or equal to about 8 mm.

[0300] For example, the aerosol-generating article may have an outer diameter of between about 5 mm and about 10 mm, or between about 5.5 mm and about 9 mm, or between about 6 mm and about 8 mm.

[0301] The outer diameter of the aerosol-generating article may be substantially constant over the entire length of the article. Alternatively, different parts of the aerosol-generating article may have different outer diameters.

[0302] One or more of the components of the aerosol-generating article may be individually defined by its own packaging.

[0303] Preferably, the aerosol-generating substrate and the downstream section are combined together in a wrapper such as a tipping wrapper.

[0304] Preferably, components of aerosol-generating articles according to the invention are made from biodegradable materials.

[0305] Preferably, an aerosol-generating article according to the invention as described herein is suitable for use in an electrically operated aerosol-generating system, wherein the aerosol-generating substrate of the heated aerosol-generating article is heated by an electric heat source.

[0306] The heating element of such an aerosol generating device may be of any suitable form to conduct heat. The heating of the aerosol generating substrate may be achieved internally, externally, or both internally and externally. The heating element may be a heating pad or a heating needle adapted to be inserted into the aerosol generating substrate so as to heat the substrate from the inside. Preferably, the heating element may preferably partially or completely surround the substrate and perform external heating of the substrate circumferentially from the outside.

[0307] The aerosol generating system may be an electrically operated aerosol generating system comprising an induction heating device. As described above, the induction heating device generally comprises an induction source configured to be coupled to a susceptor, which may be disposed externally to the aerosol generating substrate or internally to the aerosol generating substrate. The induction source generates an alternating electromagnetic field that induces magnetization or eddy currents in the susceptor. The susceptor may be heated due to hysteresis losses or induced eddy currents, which heat the susceptor by ohmic or resistive heating.

[0308] An electrically operated aerosol generating system comprising an induction heating device may also comprise an aerosol generating article having an aerosol generating substrate and a susceptor in thermal proximity to the aerosol generating substrate. Typically, the susceptor is in direct contact with the aerosol generating substrate, and heat is transferred from the susceptor to the aerosol generating substrate primarily by conduction. Examples of electrically operated aerosol generating systems having an induction heating device and aerosol generating articles having a susceptor are described in WO-A1-95 / 27411 and WO-A1-2015 / 177255.

[0309] In some cases, the electrically operated aerosol generating system may include an aerosol generating article as defined above, an aerosol forming agent source and a device for vaporizing the aerosol forming agent, preferably a heating element. The aerosol forming agent source may be a refillable or replaceable reservoir located on the aerosol generating device. When the reservoir is physically separated from the aerosol generating article, the generated vapor is guided through the aerosol generating article. The vapor contacts the aerosol generating substrate, and the aerosol generating substrate releases volatile compounds, such as nicotine and flavoring agents in the granular plant material, to form an aerosol. Optionally, in order to help the volatilization of the compounds in the aerosol generating substrate, the aerosol generating system may also include a heating element to heat the aerosol generating substrate, preferably in a coordinated manner with the aerosol forming agent. However, the heating element for heating the aerosol generating article can be separated from the heater that heats the aerosol forming agent.

[0310] As mentioned above, the hollow tubular substrate element of the aerosol-generating article according to the invention may advantageously be adapted such that the length substantially matches the longitudinal dimension of the heating element of the aerosol-generating system intended for heating the aerosol-generating article. This may ensure that the hollow tubular substrate element is heated substantially along its entire length, so that the generation of aerosol from the aerosol-generating substrate may be maximized.

[0311] 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 or embodiment or aspect described herein.

[0312] EX1: An aerosol generating article comprising a strip of an aerosol generating substrate, and a downstream section arranged downstream of the strip of aerosol generating substrate, wherein the strip of aerosol generating substrate comprises a hollow tubular substrate element formed by homogenized tobacco material and an outer wrapper defining the hollow tubular substrate element.

[0313] EX2: An aerosol-generating article according to EX1, wherein the outer wrapper is arranged such that a void space is defined between at least a portion of the outer surface of the hollow tubular matrix element and the outer wrapper.

[0314] EX3: An aerosol-generating article according to EX2, wherein the hollow tubular matrix element comprises a plurality of perforations providing fluid communication between the longitudinal lumen of the hollow tubular matrix element and the outer wrapper.

[0315] EX4: An aerosol-generating article according to any one of EX1 to EX3, wherein the hollow tubular substrate element is formed from 2 or more overlapping layers of homogenised tobacco material.

[0316] EX5: An aerosol-generating article according to any one of EX1 to EX4, wherein the hollow tubular substrate element is formed from up to 10 overlapping layers of homogenised tobacco material.

[0317] EX6: An aerosol-generating article according to any one of EX1 to EX5, wherein the hollow tubular substrate element has a length of at least about 5 mm.

[0318] EX7: An aerosol-generating article according to any one of EX1 to EX6, wherein the hollow tubular substrate element has a length of up to about 30 mm.

[0319] EX8: An aerosol-generating article according to any one of EX1 to EX7, wherein a ratio of the length of the hollow tubular substrate element to the overall length of the aerosol-generating article is at least about 0.1.

[0320] EX9: An aerosol-generating article according to any one of EX1 to EX8, wherein a ratio of the length of the hollow tubular substrate element to the overall length of the aerosol-generating article is up to about 0.6.

[0321] EX10: An aerosol-generating article according to any one of EX1 to EX9, wherein the hollow tubular substrate element has an outer diameter that is smaller than an outer diameter of the aerosol-generating article.

[0322] EX11: An aerosol-generating article according to any one of EX1 to EX10, wherein the hollow tubular substrate element has an outer diameter of at least about 5 mm.

[0323] EX12: An aerosol-generating article according to any one of EX1 to EX11, wherein the hollow tubular substrate element has an outer diameter of up to about 9 mm.

[0324] EX13: An aerosol-generating article according to any one of EX1 to EX12, wherein the hollow tubular matrix element has a wall thickness of at least about 4% of the outer diameter of the hollow tubular matrix element.

[0325] EX14: An aerosol-generating article according to any one of EX1 to EX13, wherein the hollow tubular matrix element has a wall thickness of up to about 40% of the outer diameter of the hollow tubular matrix element.

[0326] EX15: An aerosol-generating article according to any one of EX1 to EX14, wherein the hollow tubular substrate element has a wall thickness of at least about 0.3 mm.

[0327] EX16: An aerosol-generating article according to any one of EX1 to EX15, wherein the hollow tubular substrate element has a wall thickness of up to about 3 mm.

[0328] EX17: An aerosol-generating article according to any one of EX1 to EX16, wherein the longitudinal cavity has a diameter of at least about 1 mm.

[0329] EX18: An aerosol-generating article according to any one of EX1 to EX17, wherein the longitudinal cavity has a diameter of up to about 8 mm.

[0330] EX19: An aerosol-generating article according to any one of EX3 to EX18, wherein the hollow tubular substrate element comprises one or more rows of perforations extending circumferentially around the hollow tubular substrate element.

[0331] EX20: An aerosol-generating article according to any one of EX3 to EX19, wherein the hollow tubular matrix element comprises at least two rows of perforations extending circumferentially around the hollow tubular matrix element.

[0332] EX21: An aerosol-generating article according to any one of EX3 to EX20, wherein the hollow tubular substrate element comprises up to five rows of perforations extending circumferentially around the hollow tubular substrate element.

[0333] EX22: An aerosol-generating article according to any one of EX19 to EX21, wherein the circumferential rows of perforations are arranged circularly or spirally around the hollow tubular substrate element.

[0334] EX23: An aerosol-generating article according to any one of EX20 to EX22, wherein each row of circumferential perforations comprises between 8 and 30 perforations.

[0335] EX24: An aerosol-generating article according to any one of EX3 to EX23, wherein the plurality of perforations includes at least one perforation having a maximum dimension of at least about 200 microns, or wherein each perforation of the plurality of perforations has a maximum dimension of at least about 200 microns.

[0336] EX25: An aerosol-generating article according to any one of EX3 to EX24, wherein the plurality of perforations comprises at least one perforation having a maximum dimension of up to about 1 mm, or wherein each perforation of the plurality of perforations has a maximum dimension of up to about 1 mm.

[0337] EX26: An aerosol-generating article according to any one of EX3 to EX25, wherein the plurality of perforations includes at least one perforation having an opening area of ​​at least about 0.01 square millimeters, or wherein each perforation of the plurality of perforations has an opening area of ​​at least about 0.01 square millimeters.

[0338] EX27: An aerosol-generating article according to any one of EX3 to EX26, wherein the plurality of perforations includes at least one perforation having an opening area of ​​not more than 1 square millimeter, or wherein each perforation of the plurality of perforations has an opening area of ​​not more than 1 square millimeter.

[0339] EX28: An aerosol-generating article according to any one of EX3 to EX27, wherein the plurality of perforations has a total open area of ​​at least about 0.05 square millimeters.

[0340] EX29: An aerosol-generating article according to any one of EX3 to EX28, wherein the plurality of perforations has a total open area of ​​up to about 30 square millimeters.

[0341] EX30: An aerosol-generating article according to any one of EX3 to EX29, wherein the hollow tubular substrate element has a ventilation level of at least about 5%.

[0342] EX31: An aerosol-generating article according to any one of EX3 to EX30, wherein the hollow tubular substrate element has a ventilation level of up to about 60%.

[0343] EX32: An aerosol-generating article according to any one of EX3 to EX31, wherein the strip of aerosol-generating substrate comprises one or more susceptor elements positioned in contact with the hollow tubular substrate element.

[0344] EX33: An aerosol-generating article according to any one of EX1 to EX33, wherein the outer wrapper and the hollow tubular matrix element are not attached.

[0345] EX34: An aerosol-generating article according to any one of EX2 to EX33, wherein the strip of aerosol-generating substrate comprises one or more protrusions extending across the empty space between the outer surface of the hollow tubular substrate element and the outer wrapper.

[0346] EX35: An aerosol-generating article according to EX33 or EX34, wherein the one or more protrusions are integral with the hollow tubular substrate element.

[0347] EX36: An aerosol-generating article according to any one of EX33 to Ex35, wherein the one or more protrusions are non-integral with the hollow tubular substrate element.

[0348] EX37: An aerosol-generating article according to EX33, EX34 or EX36, wherein the one or more protrusions are integral with the outer wrapper.

[0349] EX38: An aerosol-generating article according to any one of EX33 to EX36, wherein the one or more protrusions are not integral with the outer wrapper.

[0350] EX39: An aerosol-generating article according to any one of EX33 to EX36 and EX38, wherein the one or more protrusions are formed of homogenised tobacco material.

[0351] EX40: An aerosol-generating article according to any one of EX33 to EX39, wherein the one or more protrusions are arranged such that the empty spaces are discontinuous.

[0352] EX41: An aerosol-generating article according to any one of EX1 to EX40, wherein the strip of aerosol-generating substrate comprises an upstream element adjacent to the upstream end of the hollow tubular substrate element.

[0353] EX42: An aerosol-generating article according to EX41, wherein the upstream element is adjacent to the upstream end of the hollow tubular substrate element.

[0354] EX43: An aerosol-generating article according to EX41 or EX42, wherein the outer wrapper defines at least a portion of the hollow tubular substrate element and the upstream element.

[0355] EX44: An aerosol-generating article according to any one of EX41 to EX43, wherein the upstream element is an upstream rod element.

[0356] EX45: An aerosol-generating article according to any one of EX41 to EX44, wherein an outer diameter of the upstream element is substantially the same as an outer diameter of the aerosol-generating article.

[0357] EX46: An aerosol-generating article according to any one of EX41 to EX45, wherein the outer diameter of the upstream element is greater than the outer diameter of the hollow tubular substrate element.

[0358] EX47: An aerosol-generating article according to any one of EX41 to EX46, wherein an outer diameter of at least a portion of the hollow tubular substrate element is at least about 0.1 mm smaller than an outer diameter of the upstream element.

[0359] EX48: An aerosol-generating article according to any one of EX41 to EX47, wherein an outer diameter of at least a portion of the hollow tubular substrate element is at least about 6 mm smaller than an outer diameter of the upstream element.

[0360] EX49: An aerosol-generating article according to any one of EX41 to EX48, wherein the upstream element has a length of between about 2 mm and about 15 mm.

[0361] EX50: An aerosol-generating article according to any one of EX1 to EX49, wherein the strip of aerosol-generating substrate comprises a downstream element adjacent to the downstream end of the hollow tubular substrate element.

[0362] EX51: An aerosol-generating article according to EX50, wherein the downstream element is adjacent to the downstream end of the hollow tubular substrate element.

[0363] EX52: An aerosol-generating article according to EX50 or EX51, wherein the outer wrapper defines at least a portion of the hollow tubular substrate element and the downstream element.

[0364] EX53: An aerosol-generating article according to any one of EX50 to EX52, wherein the downstream element is a downstream rod element.

[0365] EX54: An aerosol-generating article according to any one of EX50 to EX53, wherein an outer diameter of the downstream element is substantially the same as an outer diameter of the upstream element and an outer diameter of the aerosol-generating article.

[0366] EX55: An aerosol-generating article according to any one of EX50 to EX54, wherein the outer diameter of the downstream element is greater than the outer diameter of the hollow tubular matrix element.

[0367] EX56: An aerosol-generating article according to any one of EX50 to EX55, wherein the length of the downstream element is between about 2 mm and about 15 mm.

[0368] EX57: An aerosol-generating article according to any one of EX1 to EX56, wherein within the void space, the outer surface of the hollow tubular matrix element and the outer wrapper are separated in a radial direction by at least about 0.05 millimeters.

[0369] EX58: An aerosol-generating article according to any one of EX1 to EX57, wherein within the void space, the outer surface of the hollow tubular matrix element and the outer wrapper are separated in a radial direction by up to about 3 mm.

[0370] EX59: An aerosol-generating article according to any one of EX1 to EX58, wherein the outer wrapper has a basis weight of between about 15 g / m2 and about 100 g / m2.

[0371] EX60: An aerosol-generating article according to any one of EX1 to EX59, wherein the outer wrapper has a basis weight of at least about 80 g / m2.

[0372] EX61: An aerosol-generating article according to any one of EX1 to EX60, wherein the outer wrapper comprises a plurality of perforations overlying the hollow tubular substrate element.

[0373] EX62: An aerosol-generating article according to EX61, wherein the plurality of perforations of the outer wrapper overlie the plurality of perforations of the hollow tubular substrate element.

[0374] EX63: An aerosol-generating article according to any one of EX1 to EX62, wherein the aerosol-generating substrate has a length of between about 10 mm and about 40 mm.

[0375] EX64: An aerosol-generating article according to any one of EX1 to EX63, wherein the downstream section comprises at least one hollow tubular element.

[0376] EX65: An aerosol-generating article according to EX64, wherein a ratio of an inner diameter of the hollow tubular substrate element to an inner diameter of the hollow tubular element of the downstream section is between about 0.8 and 1.2.

[0377] EX66: An aerosol-generating article according to any one of EX1 to EX65, wherein the downstream section comprises a mouthpiece element.

[0378] EX67: An aerosol-generating article according to EX66, wherein the mouthend element comprises at least one segment of fibrous filter material.

[0379] EX68: An aerosol-generating article according to any one of EX1 to EX67, wherein the downstream section comprises a mouth-end cavity located at the downstream end.

[0380] EX69: An aerosol-generating article according to any one of EX1 to EX68, wherein the downstream segment has an overall length of between about 15 mm and about 50 mm.

[0381] EX70: An aerosol-generating article according to any one of EX1 to EX69, wherein the aerosol-generating article has an overall length of between about 35 mm and about 110 mm.

[0382] EX71: An aerosol-generating article according to any one of EX1 to EX70, wherein the outer wrapper comprises a plurality of perforations overlying the empty space.

[0383] EX72: An aerosol-generating article according to any one of EX1 to EX71, wherein the empty space has a circular cross-section. BRIEF DESCRIPTION OF THE DRAWINGS

[0384] The present invention will be further described, by way of example only, with reference to the accompanying drawings, in which:

[0385] Figure 1 shows a schematic side cross-sectional view of an aerosol-generating article according to a first embodiment of the invention;

[0386] Figure 2 A schematic side cross-sectional view of a portion of an aerosol-generating substrate is shown, comprising an aerosol-generating article and an aerosol-generating device according to a second embodiment of the invention. DETAILED DESCRIPTION

[0387] Figure 1 The aerosol-generating article 10 shown in the accompanying drawings comprises a strip 12 of an aerosol-generating substrate and a downstream section 14 disposed downstream of the strip 12 of the aerosol-generating substrate. The aerosol-generating article 10 extends from an upstream end or distal end 16 (coinciding with the upstream end of the aerosol-generating substrate 12) to a downstream end or mouth end 18 (coinciding with the downstream end of the downstream section 14). The downstream section 14 comprises a hollow tubular element 20 and a mouthpiece element 50.

[0388] The aerosol-generating article 10 has an overall length of approximately 55 mm, and an outer diameter of approximately 7.2 mm.

[0389] The aerosol-generating substrate 12 comprises a hollow tubular substrate element 40 formed from homogenized tobacco material. The hollow tubular substrate element has a peripheral wall 42 defining a longitudinal cavity 44 that provides an unrestricted flow passage through the hollow tubular substrate element 40. The upstream end of the longitudinal cavity 44 provides an air inlet through which air can be drawn into the aerosol-generating article 10 during use. The hollow tubular substrate element 40 has a length of about 12 mm.

[0390] The aerosol-generating substrate also includes an upstream rod element 70 of cellulose acetate tow adjacent to the upstream end of the hollow tubular substrate element 40 and a downstream rod element 80 of cellulose acetate tow adjacent to the downstream end of the hollow tubular substrate element 40. The upstream rod element 70 and the downstream rod element 80 each have a length of about 5 mm. The outer diameter of the upstream rod element 70 is approximately the same as the outer diameter of the downstream rod element 80, and is approximately the same as the outer diameter of the aerosol-generating article 10. The outer diameter of the hollow tubular substrate element 40 is smaller than the outer diameters of both the upstream rod element 70 and the downstream rod element 80.

[0391] The aerosol generating substrate further comprises an outer wrapper 60 which defines the hollow tubular substrate element 40, the upstream rod element 70 and the downstream rod element 80. The outer wrapper 60 is arranged such that an empty space 90 is defined between the outer surface of the hollow tubular substrate element and the outer wrapper 60.

[0392] The hollow tubular matrix element 40 includes two rows of circumferential perforations 46 that provide fluid communication between the longitudinal lumen 44 of the hollow tubular matrix element 40 and the empty space 90 between the outer surface of the hollow tubular matrix element 40 and the outer wrapper 60. The perforations 46 are disposed through the circumferential wall 42 of the hollow tubular matrix element 40.

[0393] The outer wrapper 60 also includes two rows of perforations 66 overlying the rows of perforations 46 in the hollow tubular matrix member 40 .

[0394] The hollow tubular matrix element 40 does not substantially affect the overall RTD of the aerosol-generating article. The RTD of the hollow tubular matrix element 40 is therefore approximately 0 mmH2O.

[0395] The hollow tubular element 20 of the downstream section 14 is located immediately downstream of the hollow tubular matrix element 40, and the hollow tubular element 20 is longitudinally aligned with the aerosol-generating substrate 12. The upstream end of the hollow tubular element 20 abuts the downstream end of the hollow tubular matrix element 40.

[0396] The hollow tubular element 20 is provided in the form of a hollow cylindrical tube made of cellulose acetate tow. The hollow tubular element 20 defines an inner cavity 22 extending from the upstream end of the hollow tubular element 20 to the downstream end of the hollow tubular element 20. The inner cavity 22 is substantially empty, and thus substantially unrestricted airflow is achieved along the inner cavity 22. The hollow tubular element 20 does not substantially affect the overall RTD of the aerosol-generating article 10. The RTD of the hollow tubular element 20 is therefore approximately 0 mmH2O.

[0397] like Figure 1 As shown in FIG. 1 , the inner diameter of the hollow tubular element 20 of the downstream section 14 is substantially the same as the inner diameter of the hollow tubular matrix element 40 .

[0398] The mouthpiece element 50 extends from the downstream end of the hollow tubular element 20 to the downstream or mouth end 18 of the aerosol generating article 10. The mouthpiece element 50 comprises a low density cellulose acetate filter segment. The mouthpiece element 50 may be individually wrapped by a stick wrapper (not shown).

[0399] The article 10 comprises a tipping wrapper 52 defining the hollow tubular element 20 and the mouthend element 50. The tipping wrapper 52 additionally overlies an upstream portion of the downstream rod element 80 so as to join the aerosol-generating substrate 12 and the downstream section 14.

[0400] The aerosol-generating article 10 is particularly suitable for use with an aerosol-generating device that includes an external heating device that heats the aerosol-generating substrate 12 from the outside. During use, the aerosol-generating article 10 is therefore preferably inserted into a heating chamber of the aerosol-generating device, wherein the outer surface of the hollow tubular substrate element 40 is adjacent to one or more heating elements within the heating chamber. The heating of the hollow tubular substrate element 40 generates an aerosol from the homogenized tobacco material, which is released from the inner surface of the hollow tubular substrate element 40 directly into the longitudinal cavity 44 of the hollow tubular substrate element 40, and from the outer surface of the hollow tubular substrate element 40 into the empty space 90 defined between the outer wrapper 60 and the outer surface of the hollow tubular substrate element 40. When a consumer draws on the aerosol-generating article 10, the aerosol released into the empty space 90 is drawn into the longitudinal cavity 44 of the hollow tubular matrix element 40 along with air that enters the empty space 90 through the plurality of perforations 66 in the outer wrapper 60 and through the plurality of perforations 46 in the hollow tubular matrix element 40. Air also enters the longitudinal cavity 44 of the hollow tubular matrix element 40 at the upstream end when the consumer draws on the article 10. The combined air and aerosol are drawn through the aerosol-generating article 10 and delivered to the consumer from the downstream end 18 of the aerosol-generating article 10.

[0401] Figure 2 FIG. 1 shows a portion of an aerosol generating system 100 comprising an aerosol generating device 102 and an aerosol generating article 110 according to a second embodiment of the invention. The aerosol generating article 110 is similar to Figure 1 The aerosol-generating article shown in and described above has a similar arrangement of components. However, the aerosol-generating substrate additionally includes a plurality of protrusions 148 extending across the empty space 90 between the outer surface of the hollow tubular substrate element 140 and the outer wrapper 160. The outer wrapper 160 is wrapped around the plurality of protrusions 148 to help hold the hollow tubular substrate element 140 in place and maintain the empty space 90 between the hollow tubular substrate element 140 and the outer wrapper 160. The plurality of protrusions 148 are physically distinct from the hollow tubular substrate element 140 and are directly attached to the outer surface of the hollow tubular substrate element 140.

[0402] like Figure 2 As shown in , the aerosol generating device 102 comprises a longitudinal heating chamber 104 for receiving an aerosol generating article 110. The heating chamber 104 has a closed distal end and an open mouth end. An air flow inlet 106 is provided at the distal end of the chamber so that air can be drawn through the aerosol generating article 110 during use. The heating chamber 104 comprises an external heating element 108 for resistively heating the aerosol generating substrate of the aerosol generating article 110 during use.

[0403] The aerosol-generating device 102 also includes a power source (not shown) and a controller (not shown) to controllably heat the aerosol-generating article 110 when received within the device 102 during use.

[0404] The above specific embodiments and examples are intended to illustrate the present invention, but not to limit the present invention. It should be understood that other embodiments of the present invention can be manufactured, and the specific embodiments and examples described herein are not exhaustive.

Claims

1. An aerosol generating article comprising: A strip of an aerosol-generating substrate, and a downstream section disposed downstream of the strip of aerosol-generating substrate, wherein the strip of aerosol-generating substrate comprises: a hollow tubular matrix member formed of homogenized tobacco material and defining a longitudinal lumen providing an unrestricted flow passage through the hollow tubular matrix member; an outer wrapper circumscribing the hollow tubular matrix element and arranged such that a void space is defined between at least a portion of an outer surface of the hollow tubular matrix element and the outer wrapper; wherein the hollow tubular matrix element comprises a plurality of perforations, the plurality of perforations providing fluid communication between the longitudinal lumen of the hollow tubular matrix element and the empty space between at least a portion of the outer surface of the hollow tubular matrix element and the outer wrapper, wherein a plurality of perforations of the hollow tubular matrix element are formed through a peripheral wall of the hollow tubular matrix element, and The outer wrapper includes a plurality of perforations overlying the hollow tubular matrix element.

2. An aerosol-generating article according to claim 1, wherein the hollow tubular substrate element comprises at least two rows of perforations extending circumferentially around the hollow tubular substrate element.

3. An aerosol-generating article according to claim 1 or 2, wherein each of the plurality of perforations of the hollow tubular substrate element has an open area of ​​at least about 0.01 square millimeters.

4. An aerosol-generating article according to any preceding claim, wherein the hollow tubular matrix element has a wall thickness of between about 5% and about 40% of the outer diameter of the hollow tubular matrix element.

5. An aerosol-generating article according to any preceding claim, wherein within the void space, the outer surface of the hollow tubular substrate element and the outer wrapper are separated in a radial direction by at least about 0.1 millimetres.

6. An aerosol-generating article according to any preceding claim, wherein the outer wrapper and the hollow tubular substrate element are unattached.

7. An aerosol-generating article according to any preceding claim, wherein the plurality of perforations of the outer wrapper overlie the perforations in the hollow tubular substrate element.

8. An aerosol-generating article according to any preceding claim, wherein the strip of aerosol-generating substrate further comprises an upstream rod element adjacent the upstream end of the hollow tubular substrate element, wherein the outer wrapper defines at least a portion of the hollow tubular substrate element and the upstream element.

9. An aerosol-generating article according to claim 8, wherein at least a portion of the hollow tubular substrate element has an outer diameter that is at least about 0.2 mm smaller than the outer diameter of the upstream rod element.

10. An aerosol-generating article according to claim 8 or 9, wherein the strip of aerosol-generating substrate further comprises a downstream rod element adjacent the downstream end of the hollow tubular substrate element and having the same outer diameter as the upstream rod element.

11. An aerosol-generating article according to any preceding claim, wherein the strip of aerosol-generating substrate comprises one or more protrusions extending across the empty space between the outer surface of the hollow tubular substrate element and the outer wrapper.

12. An aerosol-generating article according to any preceding claim, wherein the outer wrapper has a basis weight of at least about 80 grams per square meter.

13. An aerosol-generating article according to any preceding claim, wherein the hollow tubular substrate element is formed from two or more overlapping sheets of homogenised tobacco material.

14. An aerosol-generating article according to any preceding claim, wherein the downstream section comprises at least one hollow tubular element adjacent the downstream end of the strip of aerosol-generating substrate.

15. An aerosol-generating article according to any preceding claim, wherein the downstream section comprises at least one mouthpiece filter element.

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