Aerosol-generating article having tubular section having convex curvature at its end face

Abstract

The present invention relates to an aerosol-generating article for an aerosol-generating device, comprising a substrate section comprising an aerosol-forming substrate, a tubular section having a side wall defining a hollow interior, the tubular section being located downstream of the substrate section, wherein an upstream end of the sidewall includes an upstream end face having a convex curvature.

Description

Technical Field

[0001] The present disclosure relates to an aerosol - generating article for an aerosol - generating device, wherein the aerosol - generating article includes a substrate section and a tubular section. The present disclosure also relates to an aerosol - generating system including the aerosol - generating article and the aerosol - generating device. The present disclosure also relates to the use of the tubular section for cooling an aerosol. Background Art

[0002] It is known to provide an aerosol - generating article having a substrate section and a hollow tubular section. The substrate section may include an aerosol - forming substrate. The article may be inserted into a cavity of an aerosol - generating device for heating the substrate section. Such a device can heat the aerosol - forming substrate to a temperature at which one or more components of the aerosol - forming substrate are volatilized without burning the aerosol - forming substrate. The tubular section can be used to cool the aerosol generated from the aerosol - forming substrate of the substrate section. This can help to generate the aerosol. If the aerosol is too hot, this can prevent the user from being burned. The tubular section generally affects the draw resistance of the aerosol - generating article. When a heating element is inserted into the substrate section, the tubular section may also not provide sufficient support for the substrate section. This may result in the dislocation of the substrate section relative to the tubular section. The tubular section may also affect the aerosol formation within the aerosol - generating article. Summary of the Invention

[0003] It is desirable to provide an aerosol - generating article that provides cooling of the generated aerosol. It is also desirable to provide an aerosol - generating article that improves aerosol generation. It is also desirable to provide an aerosol - generating article that has improved support for the substrate section when a heating element is inserted into the substrate section.

[0004] According to an embodiment of the present invention, there is provided an aerosol - generating article. The aerosol - generating article may include a substrate section. The substrate section may include an aerosol - forming substrate. The aerosol - generating article may further include a tubular section having a sidewall defining a hollow interior. The tubular section may be located downstream of the substrate section. The upstream end of the sidewall may include an upstream end face having a convex curvature.

[0005] Another embodiment of the present invention may provide an aerosol - generating article. The aerosol - generating article includes a substrate section, wherein the substrate section includes an aerosol - forming substrate. The aerosol - generating article further includes a tubular section having a sidewall defining a hollow interior. The tubular section is located downstream of the substrate section. The upstream end of the sidewall includes an upstream end face having a convex curvature.

[0006] Due to the tubular section having a convex curvature at its upstream end face, the aerosol-generating article can provide additional support to the substrate section. Due to the tubular section, the draw resistance of the aerosol-generating article can be improved. Due to the tubular section, the aerosol-generating article can exhibit improved aerosol generation.

[0007] The term "convex curvature" describes that the surface of the upstream end face curves outward relative to the hollow interior of the tubular section. The term "convex curvature" is intended to describe a surface that does not form a flat plane.

[0008] The term "convex curvature" can also describe that a part of the surface of the upstream end face can bulge outward relative to the hollow interior of the tubular section.

[0009] As used herein, the terms "upstream" and "downstream" are used to describe the relative positions of sections of an aerosol-generating article or an aerosol-generating device used with the aerosol-generating article relative to the direction of aerosol delivery through the aerosol-generating article during use. The aerosol-generating article according to the present invention includes a proximal end, and during use, the aerosol exits the aerosol-generating article through the proximal end. The proximal end of the aerosol-generating device can also be referred to as the mouth end or the downstream end. During use, the user sucks on the downstream end or the mouth end of the aerosol-generating article in order to inhale the aerosol generated by the aerosol-generating system. The aerosol-generating system includes an upstream end opposite the downstream end or the mouth end. The mouth end is downstream of the distal end. The distal end of the aerosol-generating device or the aerosol-generating article can also be referred to as the upstream end. Based on their positions relative to the direction of aerosol delivery through the aerosol-generating article or the aerosol-generating device during use of the article or the aerosol-generating device, components or parts of the aerosol-generating article or the aerosol-generating device can be described as being upstream or downstream of each other.

[0010] The term "aerosol-generating article" is used herein to denote an article in which an aerosol-generating substrate is heated to provide an inhalable aerosol to a consumer. As used herein, the term "aerosol-forming substrate" denotes a substrate capable of releasing volatile compounds upon heating to generate an aerosol.

[0011] The radius of curvature of the convex curvature can be between 1.3 millimeters and 2.3 millimeters, preferably between 1.6 millimeters and 2.0 millimeters, more preferably between 1.7 millimeters and 1.9 millimeters, and more preferably about 1.8 millimeters. The upstream end face can have a circular shape.

[0012] A part of the upstream end face can be bent to extend into the hollow interior of the tubular section.

[0013] This can allow the airflow entering the tubular section to be directly guided into the tubular section through the upstream end face. This can improve aerosolization. This can also improve the draw resistance value of the tubular section.

[0014] The upstream end face may define a central orifice. The upstream end face may form a tubular upstream end portion extending from the central orifice into the hollow interior of the tubular section.

[0015] The central orifice may advantageously allow airflow from the substrate section to enter the tubular section. The tubular upstream end portion may direct the airflow into the hollow interior of the tubular section. This may improve the aerosolization process. This may advantageously cool the aerosol formed from the volatile compounds forming the matrix of the air and aerosol.

[0016] The upstream end face may include an upstream portion of the upstream end face. This upstream portion of the end face may be the portion of the upstream end face that is the most upstream in the aerosol - generating article compared to other portions of the upstream end face. Compared to other portions of the upstream end face, this upstream portion of the upstream end face may be arranged closest to the substrate section in the aerosol - generating article. In particular, the upstream portion of the upstream end face may be spaced from the substrate section by at most 5 mm, preferably less than 1 mm. Most preferably, the upstream portion of the upstream end face may be arranged adjacent to the substrate section.

[0017] The upstream end face may include a downstream portion of the upstream end face. This downstream portion of the end face may be the portion of the upstream end face that is the most downstream in the aerosol - generating article compared to other portions of the upstream end face. This downstream portion of the end face may be the portion of the upstream end face that extends into the hollow interior of the tubular section.

[0018] The aerosol - generating article may be configured to be used in combination with an aerosol - generating device. The aerosol - generating article may be configured to be insertable into a cavity of the aerosol - generating device. The aerosol - generating device may be configured to heat the aerosol - forming matrix of the substrate section to a temperature below the combustion temperature of the substrate in order to generate an aerosol.

[0019] A portion of the tubular section may be located adjacent to the substrate section.

[0020] This may ensure a higher mechanical stability of the substrate section. Due to the upstream end face having a convex curvature, this may provide additional support to the substrate section. If a heating element, such as a heating blade, is inserted into the substrate section, this may provide additional stability to the substrate section.

[0021] A portion of the tubular section may be located adjacent to the substrate section. This may advantageously support the substrate section.

[0022] The aerosol - generating article may further include a longitudinal axis. A portion of the side wall of the tubular section may extend along the longitudinal axis. A transverse portion of the upstream end face of the side wall may extend transversely to the longitudinal axis. The transverse portion of the upstream end face of the side wall may extend partially perpendicular to the longitudinal axis.

[0023] The transverse portion of the upstream end face of the side wall may comprise or form the upstream portion of the upstream end face. This portion of the upstream end face may be the most upstream portion located in the aerosol-generating article compared to other portions of the upstream end face.

[0024] The transverse portion of the upstream end face of the side wall may provide additional stability to the upstream end face and the upstream end of the tubular section.

[0025] As used herein, the term "longitudinal" refers to the direction corresponding to the main longitudinal axis of the aerosol-generating article, which extends between the upstream end and the downstream end of the aerosol-generating article.

[0026] Preferably, the transverse portion of the upstream end face may be adjacent to the substrate section. This can ensure that the upstream end face of the tubular section can support the substrate section. This can allow the aerosol generated in the substrate section to be easily transported through the upstream end face into the hollow interior of the substrate section.

[0027] Preferably, the transverse portion of the upstream end face of the tubular portion of the tubular section may be in direct contact with the downstream portion of the substrate section.

[0028] The tubular section may comprise or consist of a cellulose-based material, which is preferably paper or cardboard. This can provide additional stability to the tubular section. This can additionally support the substrate section. The cellulose-based material can be sustainable and biodegradable.

[0029] The substrate section may have a length between 10 and 13 millimeters, preferably between 11 and 12 millimeters. The length of the optional upstream filter mouthpiece section may be between 4 and 6 millimeters, preferably 5 millimeters. The diameter of all sections of the aerosol-generating article may be between 6 and 8 millimeters, preferably between 7.1 and 7.3 millimeters. The thickness of the side wall of the tubular section defining the hollow interior may be between 140 and 610 micrometers, preferably between 150 and 600 micrometers. The diameter of the central orifice of the upstream end face of the tubular section may be between 0.8 and 3.2 millimeters, preferably between 1 and 3 millimeters. The length of the downstream filter section may be between 7 and 12 millimeters.

[0030] The side wall of the tubular section may further comprise a ventilation zone. The ventilation zone may comprise perforations in the side wall. The perforations may allow air to enter the hollow interior of the tubular section. The perforations may provide an additional cooling effect to the aerosol formed by the aerosol-forming substrate in the substrate section. Preferably, the ventilation zone may be located downstream of the upstream end of the side wall. This can allow air to enter the hollow interior of the tubular section through the perforations and further mix with the airflow originating from the substrate section. The ventilation zone can improve the draw resistance (RTD) value of the aerosol-generating article.

[0031] Since the ventilated hollow tubular element has substantially no effect on the overall RTD of the aerosol-generating article, in the aerosol-generating article according to the present invention, by adjusting the length and density of the aerosol-forming substrate strip, and optionally the length and density of the filter material segment forming part of the mouthpiece, or the length and density of the filter material segment provided upstream of the aerosol-forming substrate, the overall RTD of the article can be advantageously finely adjusted. In fact, in the aerosol-generating article according to the present invention, the cavity defined internally by the hollow tubular segment enables the aerosol to flow substantially unimpeded from the upstream end of the hollow tubular segment to the downstream end. This means that the cavity is substantially empty or behaves as if it were substantially empty from the perspective of resistance to flow. Therefore, aerosol-generating articles with a predetermined RTD can be manufactured consistently and with high precision, such that a satisfactory RTD level can be provided to the consumer even in the presence of ventilation.

[0032] The aerosol-generating article may further include a filter section. The filter section may be located downstream of the tubular section. The filter section may be a mouthpiece filter section. The filter section may be used by a user consuming the aerosol-generating article to inhale the aerosol generated by the aerosol-forming substrate.

[0033] The substrate section may include a heating element. The heating element may be configured to heat the aerosol-forming substrate. Preferably, the heating element may be a susceptor heating element.

[0034] Generally, a susceptor is a material capable of absorbing electromagnetic energy and converting it into heat. When placed in an alternating electromagnetic field, eddy currents are typically induced and hysteresis losses occur in the susceptor, thereby causing heating of the susceptor. The susceptor is heated by changing the electromagnetic field generated by one or more induction coils, and the susceptor then transfers heat to the aerosol-generating article, thereby forming an aerosol. Heat transfer may occur mainly by heat conduction. Such heat transfer is optimal if the susceptor is in close thermal contact with the aerosol-generating article.

[0035] The susceptor heating element may be formed of any material that can be inductively heated to a temperature sufficient to generate an aerosol from the aerosol-forming substrate. Preferred susceptor heating elements may include ferromagnetic materials or be composed of ferromagnetic materials, such as ferromagnetic alloys, ferritic iron, or ferromagnetic steel or stainless steel. Suitable susceptors may be aluminum or include aluminum. Preferred susceptors may be heated to a temperature exceeding 250 degrees Celsius.

[0036] Preferred sensors are metal sensors, such as stainless steel. However, the sensor material may also comprise or be made of various ones of the following: graphite; molybdenum; silicon carbide; aluminum; niobium; Inconel alloy (austenite nickel-chromium based superalloy); metallized film; ceramics such as zirconia; transition metals such as iron, cobalt, nickel or metalloid components such as boron, carbon, silicon, phosphorus, aluminum.

[0037] Preferably, the sensor material is a metal sensor material.

[0038] The aerosol-generating article may also comprise an upstream filter section. The upstream filter section may be located upstream of the substrate section.

[0039] The upstream filter section may provide additional support to the substrate section. The upstream filter section may prevent accidental leakage of the aerosol-forming substrate out of the aerosol-generating article.

[0040] The aerosol-forming substrate may comprise an aerosol-forming agent. Preferably, the aerosol-forming agent may be selected from polyols, esters of polyols or aliphatic esters of mono-, di- or poly-carboxylic acids or combinations thereof. Based on the total amount of the aerosol-forming substrate, the aerosol-forming agent may be present in an amount between 10% and 50% by dry weight.

[0041] The term "by dry weight" throughout this application refers to the weight of the aerosol-forming substrate calculated using water removed by Karl-Fischer titration, for example after heating to a temperature of 110 degrees Celsius under standard conditions of temperature and pressure and determining the end point using potentiometry. The end point is detected by double potentiometric titration. A second pair of Pt electrodes is immersed in the anode solution. The detector circuit maintains a constant current between the two detector electrodes during the titration. Before the equivalence point, the solution contains I-, but contains a small amount of I2. At the equivalence point, an excess of I2 appears, and a sudden voltage drop marks the end point. Then, the amount of I2 generated and the charge required to reach the end point can be used to calculate the amount of water in the original sample. The aerosol-forming agent content can be measured by gas chromatography in combination with a flame ionization detector.

[0042] The aerosol-forming substrate may be a solid aerosol-forming substrate. The aerosol-forming substrate may include both a solid component and a liquid component. The aerosol-forming substrate may include a tobacco-containing material that contains volatile tobacco flavor compounds released from the substrate upon heating. The aerosol-forming substrate may include a non-tobacco material. The aerosol-forming substrate may include an aerosol-forming agent that facilitates the formation of a dense and stable aerosol. Suitable aerosol-forming agents are well known in the art and include, but are not limited to: polyols such as triethylene glycol, 1,3-butanediol, and glycerol; esters of polyols such as glycerol mono-, di-, or triacetate; and aliphatic esters of mono-, di-, or polycarboxylic acids such as dimethyl dodecanedioate and dimethyl tetradecanedioate. The aerosol-forming agent may be a polyol or a mixture thereof, for example, triethylene glycol, 1,3-butanediol, and glycerol. The aerosol-forming agent may be propylene glycol. The aerosol-forming agent may include both glycerol and propylene glycol.

[0043] The aerosol-forming substrate may be a solid aerosol-generating substrate.

[0044] In certain preferred embodiments, the aerosol-forming substrate includes homogenized plant material, preferably homogenized tobacco material.

[0045] As used herein, the term "homogenized plant material" encompasses any plant material formed by the coalescence of plant particles. For example, a sheet or web of homogenized tobacco material for use in the aerosol-forming substrate of the present invention may be formed by coalescing particles of tobacco material obtained by crushing, grinding, or milling plant material and optionally one or more of tobacco leaves and tobacco stems. The homogenized plant material may be produced by casting, extrusion, papermaking processes, or any other suitable process known in the art.

[0046] The homogenized plant material may be provided in any suitable form. For example, the homogenized plant material may be in the form of one or more sheets. As used herein in reference to the present invention, the term "sheet" describes a layered element having a width and length that are significantly greater than its thickness.

[0047] Alternatively or additionally, the homogenized plant material may be in the form of a plurality of pellets or microparticles.

[0048] Alternatively or additionally, the homogenized plant material may be in the form of a plurality of strands, strips, or pieces. As used herein, the term "strand" describes an elongate element material having a length that is significantly greater than its width and thickness. The term "strand" shall be considered to include strips, pieces, and any other homogenized plant material having a similar form. Strands of homogenized plant material may be formed from sheets of homogenized plant material, for example by cutting or shredding, or by other methods, such as by an extrusion method.

[0049] In some embodiments, strands may be formed in situ within the aerosol - forming substrate due to the splitting or cracking of the homogenized plant material sheet during the formation of the aerosol - forming substrate, for example due to curling. The strands of homogenized plant material within the aerosol - forming substrate may be separated from each other. Alternatively, each strand of homogenized plant material within the aerosol - forming substrate may be at least partially connected along the length of the strand to one or more adjacent strands. For example, adjacent strands may be connected by one or more fibers. This may occur, for example, in the case where strands are formed due to the splitting of the sheet of homogenized plant material during the production of the aerosol - forming substrate, as described above.

[0050] Preferably, the aerosol - forming substrate is in the form of one or more sheets of homogenized plant material. In various embodiments of the present invention, one or more sheets of homogenized plant material may be produced by a casting process. In various embodiments of the present invention, one or more sheets of homogenized plant material may be produced by a papermaking process. Each of the one or more sheets as described herein may individually have a thickness between 100 micrometers and 600 micrometers, preferably between 150 micrometers and 300 micrometers, and most preferably between 200 micrometers and 250 micrometers. The individual thickness refers to the thickness of a single sheet, while the combined thickness refers to the total thickness of all the sheets that make up the aerosol - forming substrate. For example, if the aerosol - forming substrate is formed from two separate sheets, the combined thickness is the sum of the thicknesses of the two separate sheets or the measured thickness of the two sheets in the case where the two sheets are stacked in the aerosol - forming substrate.

[0051] Each of the one or more sheets as described herein may individually have a grammage between about 100 grams per square meter and about 300 grams per square meter.

[0052] Each of the one or more sheets as described herein may individually have a density ranging from about 0.3 grams per cubic centimeter to about 1.3 grams per cubic centimeter, and preferably from about 0.7 grams per cubic centimeter to about 1.0 grams per cubic centimeter.

[0053] Volatile compounds, such as tobacco flavorings from plant material or the above - mentioned aerosol - forming agents from the aerosol - forming substrate, may evaporate during the heating of the aerosol - forming substrate. When the released volatile compounds cool, they may condense to form an aerosol. A tubular section whose upstream end face includes a convex curvature may contribute to cooling and aerosol formation.

[0054] The upstream end of the side wall may have a higher density than the downstream end of the side wall. This may provide additional mechanical stability to the tubular section. Such a tubular section may be able to better support the substrate section.

[0055] The upstream end of the sidewall may have a greater thickness than the downstream end of the sidewall. This can also provide additional mechanical stability to the tubular section. A tubular section having a greater thickness at its upstream end can also advantageously provide additional support to the matrix section.

[0056] The upstream end face including a convex curvature can be curled. Curling can be a manufacturing method capable of providing a tubular section having a convex curvature at its upstream end face. Curling can also be a manufacturing method for producing a downstream end of the sidewall having one or both of a higher density and a greater thickness than the downstream end of the sidewall.

[0057] Curling may include the steps of: providing a curling tool having a curling surface. The method may also provide the following method steps: providing a tubular section having an open tubular end. By translating the curling tool linearly towards the open end such that the curling surface contacts the open tubular end, curling of the open tubular end of the tubular section can be performed. At the same time, the curling surface can be rotated to produce an end of the sidewall including a convex curvature.

[0058] The curling tool may include a curling mechanism configured to linearly advance the curling tool along the longitudinal central axis and, at the same time, rotate the curling tool about the longitudinal central axis. The curling mechanism may be driven by one or more motors. The curling mechanism may include means for transmitting power from one or more motors to the curling head.

[0059] The curling mechanism may be configured to linearly advance the curling tool a distance between 1 mm and 10 mm, preferably between 3 mm and 7 mm, more preferably about 5 mm.

[0060] The curling mechanism may be configured to linearly advance the curling tool at a speed between 1 mm / second and 10 mm / second, preferably between 3 mm / second and 7 mm / second, more preferably about 5 mm / second.

[0061] The curling mechanism may be configured to linearly advance the curling tool with a force between 1 Newton and 20 Newtons, preferably between 3 Newtons and 15 Newtons, more preferably between 5 Newtons and 10 Newtons.

[0062] The curling mechanism may be configured to rotate the curling tool at a speed between 50 revolutions per minute and 2000 revolutions per minute, preferably between 100 revolutions per minute and 1500 revolutions per minute, more preferably between 300 revolutions per minute and 1200 revolutions per minute.

[0063] The maximum diameter of the circular opening may be between 5 mm and 10 mm, preferably between 6 mm and 9 mm.

[0064] The base of the recess may include a centrally disposed protrusion that extends proximally along the longitudinal central axis.

[0065] The centrally disposed protrusion may be conical. The centrally disposed protrusion may be pin-shaped. A pin shape may be described as conical where the lateral surface includes a concave curvature.

[0066] The centrally disposed protrusion may be shaped as a truncated pin or cone.

[0067] The centrally disposed protrusion may be hourglass-shaped.

[0068] The length of the centrally disposed protrusion may be between 0.3 mm and 3 mm, preferably between 0.5 mm and 2 mm, more preferably between 0.8 mm and 1.2 mm, and more preferably about 1 mm.

[0069] At least a portion of the sidewall of the centrally disposed protrusion may be arranged as a curled surface. The curled surface of the sidewall of the recess may be a first curled surface, and the curled surface of the sidewall of the centrally disposed protrusion may be a second curled surface. The second curled surface may include a concave curvature.

[0070] The maximum depth of the recess parallel to the longitudinal axis may be between 1 mm and 15 mm, preferably between 4 mm and 10 mm, and more preferably between 5 mm and 8 mm.

[0071] The radius of curvature of the concave curvature of one or both of the first curled surface and the second curled surface may be between 10% and 40% of the maximum diameter of the circular opening, preferably between 20% and 30%, and more preferably about 25%. As used herein, the "radius of curvature of the concave curvature" may be associated with one or both of the first curled surface and the second curled surface. The radius of curvature of the concave curvature of the first curled surface and the second curled surface may be the same or may be different.

[0072] Before the step of curling the open tubular end of the curled tubular section, the curling method may include a step of pretreating the open tubular end of the tubular section. The pretreatment may include wetting the open tubular end with an aqueous solution (e.g., in the form of a spray). The aqueous solution may be water-based and may include additives. The open tubular end may be only slightly wetted. By wetting the open tubular end, the humidity of the tubular wall of the tubular section can be increased.

[0073] The pretreatment may include treating the open tubular end of the tubular section with vapor or steam. The pretreatment may include heating the open tubular end to a temperature in the range of, for example, 30°C to 200°C.

[0074] The pretreatment may improve the curling of the open tubular end of the tubular section. The pretreatment may particularly improve the curling of the open tubular end when the open tubular end includes cardboard or paper.

[0075] Pretreatment can increase the elasticity of the edge.

[0076] The present invention also provides an aerosol generating system. The aerosol generating system may include an aerosol generating device, which includes a chamber. The aerosol generating system may also include an aerosol generating article as described herein. The chamber may be configured to receive the aerosol generating article.

[0077] Another embodiment of the present invention provides an aerosol generating system. The aerosol generating system includes an aerosol generating device, which includes a chamber. The aerosol generating system also includes an aerosol generating article as described herein. The chamber of the aerosol generating device is configured to receive the aerosol generating article.

[0078] Such an aerosol generating system may be configured to generate an aerosol-forming substrate by heating the aerosol generating article received in the chamber of the device.

[0079] The chamber of the aerosol generating device may include an inner wall having a section that projects inwardly into the chamber. These projecting sections may contact the aerosol generating article received in the chamber. These projecting sections may allow an air flow path to be formed between the inner wall of the chamber and the aerosol generating article. This may also allow an air flow path to be formed to the above-described ventilation zone of the aerosol generating article.

[0080] The aerosol generating device may include a heating element, particularly an induction heating element, such as an induction coil. When inductively heating the aerosol-forming substrate of the aerosol generating article received in the aerosol generating device, the receptor heating element of the substrate section may be heated by the alternating magnetic field of the induction heating element. This may also heat the aerosol-forming substrate. For inductive heating, the heating element preferably includes an induction coil. An alternating current may be supplied to the induction coil for generating an alternating magnetic field. The alternating current may have a high frequency. As used herein, the term "high-frequency oscillating current" refers to an oscillating current having a frequency between 500 kHz and 30 MHz. The frequency of the high-frequency oscillating current may be about 1 MHz to about 30 MHz, preferably about 1 MHz to about 10 MHz, and more preferably about 5 MHz to about 8 MHz.

[0081] The heating element may be configured to heat the aerosol generating article to a temperature in the range of 220 degrees Celsius to 400 degrees Celsius, preferably 250 degrees Celsius to 290 degrees Celsius. The heating element may be configured to heat the aerosol generating article, particularly the aerosol-forming substrate, to a temperature below the combustion temperature of the aerosol-forming substrate. This may allow the use of aerosols generated by "heat-not-burn" aerosol generating articles.

[0082] The heating element may be configured as a resistive heating element. The heating element may be configured as a resistive heating coil that at least partially surrounds a cavity for receiving an aerosol-generating article.

[0083] The heating element may be positioned adjacent to the cavity for receiving the aerosol-generating article. The heating element may be positioned at least partially around the cavity for heating the aerosol-generating article received in the cavity. The heating element may surround the perimeter of the cavity for receiving the aerosol-generating article. This may allow for reliable and uniform heating of the substrate section of the aerosol-generating article.

[0084] The heating element may comprise a resistive material. Suitable resistive materials include, but are not limited to: semiconductors (such as doped ceramics), electrically “conductive” ceramics (such as molybdenum disilicide for example), carbon, graphite, metals, metal alloys, and composite materials made of ceramic materials and metal materials. Such composite materials may include doped or undoped ceramics. Examples of suitable doped ceramics include doped silicon carbide. Examples of suitable metals include titanium, zirconium, tantalum, platinum, gold, and silver. Examples of suitable metal alloys include stainless steel, nickel-containing alloys, cobalt-containing alloys, chromium-containing alloys, aluminum-containing alloys, titanium-containing alloys, zirconium-containing alloys, hafnium-containing alloys, niobium-containing alloys, molybdenum-containing alloys, tantalum-containing alloys, tungsten-containing alloys, tin-containing alloys, gallium-containing alloys, manganese-containing alloys, gold-containing alloys, iron-containing alloys, and superalloys based on nickel, iron, cobalt, stainless steel, and iron-manganese-aluminum alloys. In the composite material, the resistive material may optionally be embedded in, encapsulated by, or coated with an insulating material or vice versa, depending on the kinetics of energy transfer and the desired external physical and chemical properties.

[0085] The above resistive heating element may also be part of the substrate section of the aerosol-generating article. In this case, the aerosol-generating device may include electrical connections for heating the resistive heating element in the substrate section.

[0086] The present invention also provides the use of a tubular element for cooling an aerosol generated by an aerosol-forming substrate. The tubular element may include sidewalls defining a hollow interior. The end portions of the sidewalls may include end faces having a convex curvature.

[0087] Another embodiment of the present invention provides the use of a tubular element for cooling an aerosol generated by an aerosol-forming substrate. The tubular element includes sidewalls defining a hollow interior. The end portions of the sidewalls include end faces having a convex curvature.

[0088] Compared with conventional tubular elements lacking end faces with a convex curvature, this use of a tubular element for cooling an aerosol may provide better cooling of the aerosol. This may also provide additional support for the substrate section including the aerosol-forming substrate.

[0089] The present invention also provides a method for producing an aerosol-generating article comprising a substrate section in a tubular section. The method may provide the following method steps: providing a tubular section having a sidewall defining a hollow interior. The tubular section may have an open end. Additionally, the method may include the following method steps: providing a curling tool having a curling surface. By translating the curling tool towards the open end such that the curling surface contacts the open tubular end, curling of the open tubular end of the tubular section may be performed. At the same time, the curling surface may be rotated to produce an end face of the sidewall comprising a convex curvature. The method may further include the following method steps: providing a substrate section comprising an aerosol-forming substrate. The substrate section may be arranged relative to the tubular section such that the end face of the sidewall of the tubular section comprising the convex curvature is positioned adjacent to the substrate section. This may produce an aerosol-generating article.

[0090] Another embodiment of the present invention provides a method for producing an aerosol-generating article comprising a substrate section and a tubular section. The method comprises the following method steps: providing a tubular section having a sidewall defining a hollow interior, wherein the tubular section has an open end. A curling tool is provided with a curling surface. The method also comprises the following method steps: curling the open tubular end of the tubular section by translating the curling tool towards the open end such that the curling surface contacts the open tubular end. At the same time, the curling surface is rotated in order to produce an end face of the sidewall comprising a convex curvature. The method also comprises the following method steps: providing a substrate section comprising an aerosol-forming substrate. The substrate section is arranged relative to the tubular section such that the end face of the sidewall of the tubular section comprising the convex curvature is positioned adjacent to the substrate section, thereby producing an aerosol-generating article.

[0091] This production method is a simple method for providing an aerosol-generating article according to the present invention comprising a substrate section and a tubular section, wherein the upstream end face comprises a convex curvature.

[0092] This may provide a method for producing an aerosol-generating article which reliably and reproducibly allows for the automated manufacture of the article. This may also allow for the production of aerosol-generating articles at a sufficiently high speed. This may allow for the manufacture of aerosol-generating articles having a consistent appearance of their tubular sections.

[0093] By curling the open tubular end of the tubular section, a curled end face with increased mechanical stability of the tubular end may be provided. A method for producing a structurally enhanced aerosol-generating article may be provided. The curled end face of the tubular section may provide increased hardness. The curled end face may provide additional support and stability for the substrate section of the aerosol-generating article. The curled end face having a convex curvature may also be less prone to deformation.

[0094] The tubular section may include a longitudinal axis, preferably a central longitudinal axis. During the step of advancing the curling tool translationally towards the open end and simultaneously rotating the curling surface of the curling tool, the open end of the tubular section may be folded towards the central longitudinal axis of the tubular section.

[0095] The method may further include the method step of attaching a substrate section to the tubular section. This may increase the stability of the aerosol-generating article. Preferably, the substrate section is attached to the tubular section by wrapping paper around at least partially the substrate section and the tubular section. This wrapping paper may provide additional stability to the aerosol-generating article. This wrapping paper may allow for easy placement of the substrate section relative to the tubular section. The wrapping paper may be a single-piece member that wraps around at least several portions of the substrate section and the tubular section for connecting the two sections.

[0096] A curling tool with a concave curling surface may be employed. This may allow for the easy formation of an upstream end face with a convex curvature during the curling process.

[0097] Preferably, the curling surface of the curling tool includes a concave curvature. More preferably, the curling surface is arranged rotationally symmetrically around a central axis.

[0098] A non-exhaustive list of non-limiting examples is provided below. Any one or more features of these examples may be combined with any one or more features of another example, embodiment, or aspect described herein.

[0099] Example E1: An aerosol-generating article comprising

[0100] a substrate section comprising an aerosol-forming substrate,

[0101] a tubular section having a side wall defining a hollow interior, the tubular section being downstream of the substrate section, wherein an upstream end of the side wall includes an upstream end face having a convex curvature.

[0102] Example E2: The aerosol-generating article according to Example E1, wherein a portion of the upstream end face is curved to extend into the hollow interior of the tubular section.

[0103] Example E3: The aerosol-generating article according to any one of the preceding examples, wherein the upstream end face defines a central orifice, preferably wherein the upstream end face forms a tubular upstream end portion extending from the central orifice into the hollow interior of the tubular section.

[0104] Example E4: The aerosol-generating article according to any one of the preceding examples, wherein a portion of the tubular section is located adjacent to the substrate section.

[0105] Example E5: The aerosol-generating article according to any one of the preceding examples further includes a longitudinal axis, wherein a transverse portion of the upstream end face of the side wall extends transversely to the longitudinal axis, preferably wherein the transverse portion of the upstream end face is adjacent to the matrix section, and more preferably wherein the transverse portion of the upstream end face of the tubular portion directly contacts the downstream portion of the matrix section.

[0106] Example E6: The aerosol-generating article according to any one of the preceding examples, wherein the tubular section comprises or consists of a cellulose-based material, and the cellulose-based material is preferably paper or cardboard.

[0107] Example E7: The aerosol-generating article according to any one of the preceding examples, wherein the side wall of the tubular section further includes a ventilation zone, and the ventilation zone includes perforations in the side wall, preferably wherein the ventilation zone is located downstream of the upstream end of the side wall.

[0108] Example E8: The aerosol-generating article according to any one of the preceding examples further includes a filter section, wherein the filter section is located downstream of the tubular section, preferably wherein the filter section is a mouthpiece filter section.

[0109] Example E9: The aerosol-generating article according to any one of the preceding examples, wherein the matrix section includes a heating element configured to heat the aerosol-forming matrix, preferably wherein the heating element is a susceptor heating element.

[0110] Example E10: The aerosol-generating article according to any one of the preceding examples further includes an upstream filter section, wherein the upstream filter section is located upstream of the matrix section.

[0111] Example E11: The aerosol-generating article according to any one of the preceding examples, wherein the aerosol-forming matrix contains an aerosol-forming agent, preferably wherein the aerosol-forming agent is selected from polyols, esters of polyols, or aliphatic esters of mono-, di- or polycarboxylic acids or combinations thereof, and more preferably wherein based on the total amount of the aerosol-forming matrix, the aerosol-forming agent is present in an amount between 10% and 50% by dry weight.

[0112] Example E12: The aerosol-generating article according to any one of the preceding examples, wherein the upstream end of the side wall has a higher density than the downstream end of the side wall.

[0113] Example E13: The aerosol-generating article according to any one of the preceding examples, wherein the upstream end of the side wall has a greater thickness than the downstream end of the side wall.

[0114] Example E14: An aerosol-generating article according to any one of the preceding examples, wherein the upstream end face including the convex curvature is curled.

[0115] Example E15: An aerosol-generating article according to the previous example, wherein the curling comprises the steps of:

[0116] Providing a curling tool having a curled surface,

[0117] Providing a tubular section having an open tubular end, and

[0118] Curling the open tubular end of the tubular section by translationally advancing the curling tool towards the open end such that the curled surface contacts the open tubular end and simultaneously rotating the curled surface to produce an end of the side wall including a convex curvature.

[0119] Example E16: An aerosol-generating system, the aerosol-generating system comprising: an aerosol-generating device including a chamber; and an aerosol-generating article according to any one of the preceding examples, wherein the chamber is configured to receive the aerosol-generating article.

[0120] Example E17: An aerosol-generating system according to the previous example, wherein the aerosol-generating article includes a susceptor heating element, and the aerosol-generating device includes an induction coil configured to generate an alternating magnetic field in the susceptor heating element.

[0121] Example E18: An aerosol-generating system according to Example E16, wherein the aerosol-generating device includes a heating element at least partially surrounding the chamber, wherein the heating element is configured to heat the aerosol-generating article received in the chamber.

[0122] Example E19: Use of a tubular element for cooling an aerosol generated by an aerosol-forming substrate, wherein the tubular element includes a side wall defining a hollow interior, wherein an end portion of the side wall includes an end face having a convex curvature.

[0123] Example E20: A method for producing an aerosol-generating article including a substrate section and a tubular section, the method including the following method steps:

[0124] - Providing a tubular section having a side wall defining a hollow interior, wherein the tubular section has an open end,

[0125] - Providing a curling tool having a curled surface,

[0126] -Advancing the curling tool translationally towards the open end such that the curling surface contacts the open tubular end and simultaneously rotating the curling surface to produce an end face of the side wall including a convex curvature, curling the open tubular end of the tubular section, and

[0127] -Providing a substrate section including an aerosol-forming substrate, and

[0128] -Arranging the substrate section relative to the tubular section such that the end face of the side wall of the tubular section including the convex curvature is positioned adjacent to the substrate section, thereby producing the aerosol-generating article.

[0129] Example E21: The method for producing an aerosol-generating article according to the previous example, further comprising the following method steps:

[0130] -Attaching the substrate section to the tubular section, preferably wherein the substrate section is attached to the tubular section by wrapping paper at least partially around the substrate section and the tubular section.

[0131] Example E22: The method for producing an aerosol-generating article according to any one of Example E20 or E21, wherein the curling surface is concave, and preferably wherein the curling surface includes a concave curvature, more preferably wherein the curling surface is arranged rotationally symmetrically about a central axis.

[0132] Features described with respect to one embodiment may equally apply to other embodiments of the present invention. Description of the Drawings

[0133] The present invention will be further described only by way of example with reference to the accompanying drawings, wherein:

[0134] Figure 1 A cross-sectional view showing an aerosol-generating article according to an embodiment of the present invention;

[0135] Figure 2 A cross-sectional view showing a cut of a tubular section whose upstream end face includes a convex curvature;

[0136] Figure 3 A photograph showing three tubular sections whose upstream end faces have a convex curvature; and

[0137] Figure 4 a to 4c depict cross-sectional views of different method steps for producing an aerosol-generating article according to an embodiment of the method of the present invention. Detailed Description

[0138] Hereinafter, elements having the same function in all the figures are denoted by the same reference numerals.

[0139] Figure 1 A cross-sectional view of an aerosol-generating article 10 including a tubular section 12 is shown. The aerosol-generating article has an optional downstream filter section 20 and a substrate section 14. The substrate section 14 may optionally include a heating element 16, which may be a susceptor for inductive heating or a resistive heating element for heating an aerosol-forming substrate included in the substrate section. The tubular section 12 is located downstream of the substrate section 14 and includes an upstream end face 12A having a convex curvature. The upstream end face 12A also includes a transverse portion 12B of the upstream end face, which extends transversely, particularly perpendicular to the central longitudinal axis 26 of the aerosol-generating article. At least this transverse portion 12B directly contacts several portions of the substrate section 14 and thus supports the substrate section 14. Compared with other portions of the upstream end face, this transverse portion 12B forms the most upstream portion of the upstream end face. The upstream end face 12A having a convex curvature may also include an upstream end portion 12D of the end face that extends into the hollow interior 12C of the tubular section 12. This upstream end portion 12D may also be used as an air flow guiding element that guides the air flow originating from the substrate section 14 through the central orifice 15 of the upstream end face into the hollow interior 12C of the tubular section 12. Compared with other portions of the upstream end face, this upstream end portion 12D forms the most downstream portion of the upstream end face. The tubular section 12 includes a side wall 13 that defines the hollow interior 12C. As Figure 1 shown, the portion of the side wall 13 at the upstream end of the tubular section 12 forms the upstream end face 12A having a convex curvature. The different sections of the aerosol-generating article 10 are held together by a wrapper 18, which at least partially wraps around the substrate section 14, the tubular section 12, and the downstream filter section 20. The downstream portion of the tubular section 12 includes a ventilation area 21 having perforations in the side wall 13. This ventilation area allows air to enter the hollow interior 12C of the tubular section 12. This air can be mixed with the air flow originating from the substrate section 14. This can allow for an improved aerosolization process and cooling.

[0140] Figure 2 A cross-sectional view of a cutout of a tubular section whose upstream end face 12A has a convex curvature is depicted. This figure shows the design of the upstream end face 12A in more detail, where the upstream end portion 12D extends into the hollow interior 12C of the tubular section. The end face portion 12B that extends transversely to the longitudinal axis 26 of the aerosol-generating article or the tubular section itself can be seen in more detail.

[0141] Figure 3 A photograph of three separate tubular sections 12 is shown, which shows their upstream end faces in more detail. The upstream end faces define corresponding central orifices 15. The orifices 15 allow the air flow from the substrate section to enter the hollow interior of the tubular section.

[0142] Figure 4 Figure a depicts a cross-sectional view of the method steps of providing a tubular section 12 with a side wall defining a hollow interior 12C, the tubular section being connected to a downstream filter section 20, thereby forming an arrangement 11. The tubular section 12 includes an open tubular end 23. A curling tool 22 is provided having a curling surface 24 with a concave curvature, the curling surface having a central projection 25. The curling tool 22 is moved towards the arrangement 11 along the central axis 26 of both the curling tool and the tubular section.

[0143] Figure 4 Figure b depicts the process steps of translating the curling tool along the central axis 26 towards the open end 23 as shown by the arrow 30. At the same time, as shown by the arrow 32, the curling tool 22 rotates about the central axis 26 in order to curl the open tubular end 23. In Figure 4 Figure B, the axis of rotation coincides with the direction in which the curling surface of the curling tool translates forward towards the open end of the tubular section. It is also possible that the axis of rotation can be inclined with respect to the translational movement along the central axis 26. For example, the axis of rotation can be inclined at an angle of less than 90 degrees, preferably less than 45 degrees, more preferably less than 1 degree with respect to the direction in which the curling surface translates forward along the central axis 26. The open tubular end is deformed during the simultaneous translational and rotational movement of the curling tool, thereby forming an upstream end face with a convex curvature. The concave curvature of the curling surface of the curling tool ensures the formation of an upstream end face with a convex curvature. Additionally, when the curling tool translates towards the open tubular end and rotates simultaneously, the central projection 25 allows the formation of a central orifice 15. The final result of the curling procedure is shown in the cross-sectional view of Figure 4 Figure c. An upstream end face 12A with a convex curvature is formed. The central orifice 15 is defined by the upstream end face.

Claims

1. An aerosol-generating article, comprising a substrate section comprising an aerosol-forming substrate, a tubular section having a sidewall defining a hollow interior, the tubular section being located downstream of the substrate section, wherein an upstream end of the sidewall comprises an upstream end face having a convex curvature, and wherein a portion of the tubular section is positioned adjacent to the substrate section.

2. The aerosol-generating article according to claim 1, wherein a portion of the upstream end face is curved to extend into the hollow interior of the tubular section.

3. The aerosol-generating article according to any one of the preceding claims, wherein the upstream end face defines a central orifice, preferably wherein the upstream end face forms a tubular upstream end portion extending from the central orifice into the hollow interior of the tubular section.

4. The aerosol-generating article according to any one of the preceding claims, further comprising a longitudinal axis, wherein a transverse portion of the upstream end face of the sidewall extends transversely to the longitudinal axis, preferably wherein the transverse portion of the upstream end face is adjacent to the substrate section, more preferably wherein the transverse portion of the upstream end face of the tubular portion directly contacts a downstream portion of the substrate section.

5. The aerosol-generating article according to any one of the preceding claims, wherein the tubular section comprises or consists of a cellulose-based material, the cellulose-based material preferably being paper or cardboard.

6. The aerosol-generating article according to any one of the preceding claims, wherein the sidewall of the tubular section further comprises a ventilation zone, wherein the ventilation zone comprises perforations in the sidewall, preferably wherein the ventilation zone is located downstream of the upstream end of the sidewall.

7. The aerosol-generating article according to any one of the preceding claims, further comprising a filter section, wherein the filter section is located downstream of the tubular section, preferably wherein the filter section is a mouthpiece filter section.

8. The aerosol-generating article according to any one of the preceding claims, wherein the substrate section comprises a heating element, wherein the heating element is configured to heat the aerosol-forming substrate, preferably wherein the heating element is a susceptor heating element.

9. The aerosol-generating article according to any one of the preceding claims, further comprising an upstream filter section, wherein the upstream filter section is located upstream of the substrate section.

10. The aerosol-generating article according to any one of the preceding claims, wherein the aerosol-forming substrate comprises an aerosol-forming agent, preferably wherein the aerosol-forming agent is selected from polyols, esters of polyols, or aliphatic esters of mono-, di- or polycarboxylic acids, or combinations thereof, more preferably wherein, based on the total amount of the aerosol-forming substrate, the aerosol-forming agent is present in an amount between 10% and 50% by dry weight.

11. The aerosol-generating article according to any one of the preceding claims, wherein the upstream end of the sidewall has a higher density than the downstream end of the sidewall.

12. The aerosol-generating article according to any one of the preceding claims, wherein an upstream end of the side wall has a greater thickness than a downstream end of the side wall.

13. The aerosol-generating article according to any one of the preceding claims, wherein the upstream end face including the convex curvature is curled.

14. An aerosol generating system, the aerosol generating system comprising: An aerosol-generating device, the aerosol-generating device including a chamber; and an aerosol-generating article according to any one of the preceding claims, wherein the chamber is configured to receive the aerosol-generating article.

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