Aerosol-generating article with humidity-sensitive material

Abstract

The present invention relates to an aerosol-generating article comprising: a substrate portion comprising an aerosol-forming substrate. The aerosol-generating article also includes a ventilation portion downstream of the substrate portion. The ventilation portion includes perforations in a sidewall of the ventilation portion. The perforations are configured to allow ambient air to be drawn through the perforations into the ventilation portion. The aerosol-generating article also includes a front wand upstream of the substrate portion. The front rod includes a humidity-sensitive material that expands when subjected to increased humidity such that the suction resistance of the front rod increases and contracts when subjected to reduced humidity such that the suction resistance of the front rod decreases. The invention also relates to an aerosol-generating system comprising the aerosol-generating article and an aerosol-generating device. The invention also relates to the use of the humidity-sensitive material in an aerosol-generating article.

Description

[0001] The present invention relates to an aerosol-generating article.

[0002] It is known to provide an aerosol-generating article for generating an inhalable vapor. This aerosol-generating article can be used in an aerosol-generating device. Such a device can heat an aerosol-forming substrate to a temperature at which one or more components of the aerosol-forming substrate volatilize, without burning the aerosol-forming substrate. The aerosol-forming substrate can be provided as part of the aerosol-generating article. The aerosol-generating article can have a strip shape for inserting the aerosol-generating article into a cavity (such as a heating chamber) of an aerosol-generating device. A heating element can be arranged in or around the heating chamber so as to heat the aerosol-forming substrate once the aerosol-generating article is inserted into the heating chamber of the aerosol-generating device. The user experience can depend on the ambient humidity. In particular, for the first puff, when the ambient humidity is high, the user may experience an undesirable warming sensation.

[0003] It would be desirable to have an aerosol-generating article that reduces or prevents an undesirable warming sensation during a puff when the ambient humidity is high. It would be desirable to have an aerosol-generating article that reduces or prevents an undesirable warming sensation during the first puff when the ambient humidity is high. It would be desirable to have an aerosol-generating article that can deliver a more uniform aerosol when the ambient humidity is high.

[0004] According to an embodiment of the present invention, an aerosol-generating article is provided, which may include: a substrate portion including an aerosol-forming substrate. The aerosol-generating article may also include a ventilation portion downstream of the substrate portion. The ventilation portion may include perforations in a side wall of the ventilation portion. The perforations may be configured to allow ambient air to be drawn into the ventilation portion through the perforations. The aerosol-generating article may also include a front rod upstream of the substrate portion. The front rod may include a moisture-sensitive material that expands when subjected to increased humidity such that the front rod's resistance to draw increases, and contracts when subjected to decreased humidity such that the front rod's resistance to draw decreases.

[0005] According to an embodiment of the present invention, an aerosol-generating article is provided, comprising: a substrate portion comprising an aerosol-forming substrate. The aerosol-generating article further comprises a ventilation portion downstream of the substrate portion. The ventilation portion comprises perforations in a sidewall of the ventilation portion. The perforations are configured to allow ambient air to be drawn into the ventilation portion through the perforations. The aerosol-generating article further comprises a front rod upstream of the substrate portion. The front rod comprises a moisture-sensitive material that expands when subjected to increased humidity such that the front rod's resistance to draw increases, and contracts when subjected to decreased humidity such that the front rod's resistance to draw decreases.

[0006] Increasing the front rod's resistance to draw in an environment with relatively high humidity can increase the resistance to draw of the entire aerosol-generating article. In environments with relatively high humidity, it may be desirable to increase the resistance to draw of the entire aerosol-generating article. In particular, in such situations, increasing the resistance to draw of the entire aerosol-generating article can be beneficial because the user can draw less aerosol into their mouth during the first puff. This can reduce the undesirable sensation of warmth when the ambient humidity is high. Particularly preferably, providing a venting portion with perforations in its sidewall can synergistically interact with the increase in the resistance to draw of the upstream moisture-sensitive material. More specifically, if the resistance to draw of the moisture-sensitive material increases, more ambient air will be drawn into the aerosol-generating article through the venting portion downstream of the moisture-sensitive material. This can dilute the generated aerosol. This can also cool the generated aerosol. The aerosol will be generated with a higher ratio of ambient air to air drawn through the entire aerosol-generating article, resulting in a gentler experience for the user, particularly during the first puff.

[0007] Reducing the front stick's resistance to draw in an ambient environment with relatively low humidity can reduce the resistance to draw of the entire aerosol-generating article. In this way, the user experience can be optimized for the current humidity of the ambient environment. More specifically, in low-humidity environments, less ambient air will be drawn into the aerosol-generating article through the perforations of the vent portion. Consequently, due to the lower ratio of ambient air to air drawn through the entire aerosol-generating article, the user will experience a desired, more intense experience.

[0008] In other words, the present invention provides an aerosol-generating article that passively and automatically adjusts the ratio of ambient air drawn into the aerosol-generating article through the perforations of the ventilation zone to the air drawn through the entire aerosol-generating article, depending on the humidity of the surrounding environment. As a result, an undesirable warming sensation during a user's puff when the ambient humidity is high is reduced or prevented.

[0009] The moisture-sensitive material can be arranged in direct fluid contact with the surrounding environment. At least the distal surface of the moisture-sensitive material reduces or prevents an undesirable warming sensation when the ambient humidity is high. Thus, the moisture-sensitive material is resistant to ambient humidity. The moisture-sensitive material can absorb more or less moisture from the surrounding environment depending on the humidity of the surrounding environment. This, in turn, may cause the moisture-sensitive material to expand in the presence of a high-humidity ambient environment.

[0010] The moisture-sensitive material may expand when subjected to increased humidity and may contract when subjected to decreased humidity. Alternatively, the moisture-sensitive material may expand when subjected to increased humidity and may not expand when subjected to decreased humidity. Alternatively, the moisture-sensitive material may expand when subjected to increased humidity and may not expand when subjected to decreased humidity.

[0011] The term "expansion" refers to an increase in volume. The term "contraction" refers to a decrease in volume. For example, a 10% expansion may mean that the volume has increased by 10%.

[0012] The property of moisture-sensitive materials to expand when subjected to relatively high humidity can cause an increase in draw resistance due to the moisture-sensitive material being confined within the aerosol-generating article. More specifically, tipping paper can be disposed around the periphery of the moisture-sensitive material to form a front stick. This tipping paper can prevent radial expansion of the moisture-sensitive material. Thus, the expansion of the moisture-sensitive material can be internal expansion, which reduces the ability of air to flow through the moisture-sensitive material.

[0013] When the moisture sensitive material is subjected to an increase in humidity from 50% relative humidity to 75% relative humidity, the moisture sensitive material may expand by at least 10%, preferably by at least 20%, more preferably by at least 30%, and most preferably by at least 40%.

[0014] Expansion of the moisture-sensitive material can be a material property observed when the moisture-sensitive material is unrestrained. As mentioned herein, the moisture-sensitive material can be confined within the aerosol-generating article via tipping paper surrounding the periphery of the moisture-sensitive material, thereby forming a front stick. Therefore, expansion can reduce the ability of the moisture-sensitive material to allow airflow through the material due to a reduction in the cross-sectional area through which the moisture-sensitive material flows.

[0015] When the moisture-sensitive material is subjected to an increase in humidity from 50% relative humidity to 75% relative humidity, the cross-section of the flow through the moisture-sensitive material may be reduced by at least 10%, preferably by at least 20%, more preferably by at least 30%, and most preferably by at least 40%.

[0016] Instead of using the expansion / contraction of the moisture-sensitive material to describe the increased suction resistance of the front rod under high humidity conditions and the decreased suction resistance under low humidity conditions, the increase / decrease in weight of the moisture-sensitive material can be used. More specifically, the moisture-sensitive material absorbs moisture under high humidity conditions, increasing its weight in the process. This increased weight reduces the moisture-sensitive material's ability to allow airflow through it. Consequently, the increased weight due to moisture absorption increases the suction resistance. Therefore, measuring the weight difference can indicate the expansion or contraction of the moisture-sensitive material.

[0017] When the moisture sensitive material is subjected to an increase in humidity from 50% relative humidity to 75% relative humidity, the resistance to draw of the front rod may increase by at least 10%, preferably by at least 20%, more preferably by at least 40%, and most preferably by at least 60%.

[0018] The moisture-sensitive material may comprise one or more materials from the following list: EVA resin; superabsorbent polymer; carboxymethyl cellulose (CMC); polyester; acrylamide; HNBR rubber; acrylate copolymer; polyacrylic acid; polyamide; cross-linked polysaccharide; alginate-coated paper; viscose; acylated soy protein; starch-g-polyacrylonitrile; synthetic hydrogel; polyvinyl alcohol; polyethylene glycol; natural hydrogel; hyaluronic acid; chitosan; heparin; alginate.

[0019] The moisture sensitive material may comprise EVA resin, super absorbent polymer and CMC, preferably consists of EVA resin, super absorbent polymer and CMC. The moisture sensitive material may comprise or consist of EVA resin, super absorbent polymer and CMC as described in JP2014198760A.

[0020] The humidity sensitive material may comprise acrylamide and CMC, preferably consist of acrylamide and CMC. The humidity sensitive material may comprise or consist of acrylamide and CMC as described in WO2016163160 A1.

[0021] The moisture sensitive material may comprise, preferably consist of, HNBR rubber or acrylate copolymer and CMC.The moisture sensitive material may comprise or consist of HNBR rubber or acrylate copolymer and CMC as described in US 2009 / 0084550A1.

[0022] The moisture sensitive material may comprise, preferably consist of, polyacrylic acid or polyamide and a filler material.The moisture sensitive material may comprise or consist of polyacrylic acid or polyamide and a filler material as described in US 2006 / 0086501 A1.

[0023] The humidity sensitive material may comprise, preferably consist of, a cross-linked polysaccharide.The humidity sensitive material may comprise or consist of a cross-linked polysaccharide as described in EP0566118A1.

[0024] The moisture sensitive material may comprise, and preferably consists of, polyvinyl alcohol (PVA) coated curling paper.

[0025] The moisture sensitive material may comprise, and preferably consists of, 78 gsm curling paper and polysaccharide.

[0026] The moisture sensitive material may comprise, or preferably consists of, superperga 43gsm curling paper and 16gsm skalax.

[0027] The front rod can include a paper substrate. The moisture-sensitive material described herein can be added to the paper substrate. The paper substrate can be impregnated with the moisture-sensitive material described herein. Preferably, up to 20% by weight of the moisture-sensitive material can be added to the paper substrate. Preferably, the paper substrate can be impregnated with up to 20% by weight of the moisture-sensitive material. Particularly preferably, between 5% and 10% by weight of the moisture-sensitive material can be added to the paper substrate. Particularly preferably, the paper substrate can be impregnated with between 5% and 10% by weight of the moisture-sensitive material.

[0028] The front rod may comprise a nonwoven material. The moisture-sensitive material described herein may be added to the nonwoven material. The nonwoven material may be impregnated with the moisture-sensitive material described herein. Preferably, up to 30% by weight of the moisture-sensitive material may be added to the nonwoven material. Preferably, the nonwoven material may be impregnated with up to 30% by weight of the moisture-sensitive material. Particularly preferably, between 10% and 20% by weight of the moisture-sensitive material may be added to the nonwoven material. Particularly preferably, the nonwoven material may be impregnated with between 10% and 20% by weight of the moisture-sensitive material.

[0029] The front rod may comprise a fibrous material. The moisture sensitive material may be added to the fibrous material as a coating.

[0030] One or more of a paper substrate, a nonwoven material, and a fibrous material may serve as a support material for the moisture sensitive material.

[0031] The front-stick may have a resistance to draw of between 10 mmWg and 40 mmWg, preferably between 15 mmWg and 30 mmWg at 50% relative humidity.

[0032] The front-stick may have a resistance to draw of between 20 mmWg and 60 mmWg, preferably between 30 mmWg and 50 mmWg at 75% relative humidity.

[0033] The aerosol-generating article may have a diameter of between 4.5 mm and 8.0 mm, preferably between 5.0 mm and 7.5 mm, more preferably 7.3 mm.

[0034] The front rod may have a length between 3 mm and 7 mm, preferably between 4 mm and 6 mm, more preferably 5 mm.

[0035] The matrix portion may have a length between 9.0 mm and 15.0 mm, preferably between 10.5 mm and 13.5 mm, more preferably 12.0 mm.

[0036] The venting portion may be configured as a cooling portion having a length between 17 mm and 25 mm, preferably between 19 mm and 22 mm, more preferably 21 mm.

[0037] The ventilation rate of the ventilated portion may be between 30% and 50%, preferably between 35% and 45%, and more preferably 40%.

[0038] The perforations may be configured as described in PCT / EP2022 / 073899. In particular, the ventilated portion of the present application may correspond to a ventilated area as described in PCT / EP2022 / 073899, the ventilated area having corresponding perforations as described in PCT / EP2022 / 073899.

[0039] The vent portion may have side walls made of cardboard.

[0040] The structural integrity of the ventilation portion may be enhanced by the cardboard sidewalls. The cardboard sidewalls may be circular. The ventilation portion may not include any additional components other than the cardboard sidewalls and any tipping paper surrounding the perimeter of the cardboard sidewalls. The ventilation portion may include tipping paper surrounding the perimeter of the cardboard sidewalls. The ventilation portion may be composed of cardboard. The ventilation portion may be composed of cardboard and tipping paper, with perforations extending through the sidewalls and tipping paper.

[0041] The tipping paper may extend upstream or downstream of the ventilation portion to one or more elements of the aerosol-generating article to hold the corresponding elements of the aerosol-generating article together. In particular, the tipping paper may extend downstream toward the mouthpiece filter to hold the ventilation portion and the mouthpiece filter together. The tipping element may extend upstream toward the base portion to hold the ventilation portion and the base portion together. The tipping paper may be wrapped around the periphery of one or more of the ventilation portion, the mouthpiece filter, and the base portion.

[0042] The aerosol-generating article may further comprise a mouthpiece filter downstream of the ventilation portion and preferably having a length of between 5 mm and 9 mm, preferably between 6 mm and 8 mm, more preferably 7 mm.The mouthpiece filter may comprise cellulose acetate.

[0043] The resistance to draw of an aerosol-generating article may be the sum of the individual resistance to draw values ​​of the individual elements of the aerosol-generating article. In other words, the resistance to draw of the aerosol-generating article may be the resistance to draw of the front-rod plus the resistance to draw of the matrix portion plus the resistance to draw of the vent portion plus the resistance to draw of the mouthpiece filter plus the resistance to draw of any additional elements of the aerosol-generating article that contribute to the resistance to draw. Due to the hollow nature of the vent portion, the resistance to draw of the vent portion may be zero or close to zero.

[0044] The aerosol-forming substrate may comprise cut filler.The aerosol-forming substrate may comprise 16 to 20 wt% aerosol-former, preferably 17 to 19 wt% aerosol-former, more preferably 18 wt% aerosol-former.

[0045] The aerosol-forming substrate may have a bulk density of between 0.28 mg / mm3 and 0.36 mg / mm3, preferably between 0.30 mg / mm3 and 0.34 mg / mm3, more preferably 0.32 mg / mm3.

[0046] The matrix portion may have a resistance to suction of between 24 mmWG and 36 mmWG, preferably between 27 mmWG and 33 mmWG, more preferably 30 mmWG.

[0047] The present invention also relates to an aerosol-generating system, which may comprise an aerosol-generating article as described herein, and may comprise an aerosol-generating device having a cavity for receiving the aerosol-generating article.

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

[0049] As used herein, the terms "proximal", "distal", "upstream" and "downstream" are used to describe the relative position of a component or part of a component of an aerosol-generating device or an aerosol-generating article relative to the direction in which a user draws inhalation on the aerosol-generating device or aerosol-generating article during use.

[0050] An aerosol-generating device may include a mouth end through which, during use, an aerosol leaves the aerosol-generating device and is delivered to a user. The mouth end may also be referred to as a proximal end. During use, the user draws on the proximal end or mouth end of the aerosol-generating device to inhale the aerosol generated by the aerosol-generating device. Alternatively, and particularly preferably, the user may draw directly on an aerosol-generating article inserted into an opening at the proximal end of the aerosol-generating device. In this case, the user preferably draws on a front stick of the aerosol-generating article. The opening at the proximal end of the aerosol-generating device may be an opening of a cavity. The cavity may be configured to receive the aerosol-generating article. The aerosol-generating device includes a distal end opposite the proximal end or mouth end. The proximal end or mouth end of the aerosol-generating device may also be referred to as a downstream end, while the distal end of the aerosol-generating device may also be referred to as an upstream end. Components or portions of components of the aerosol-generating device may be described as being upstream or downstream of one another based on their relative position between the proximal end, downstream end, or mouth end and the distal end or upstream end of the aerosol-generating device.

[0051] As used herein, an "aerosol-generating device" refers to a device that interacts with an aerosol-forming substrate to generate an aerosol. The aerosol-forming substrate may be part of an aerosol-generating article, such as a smoking article. The aerosol-generating device may be a smoking device that interacts with the aerosol-forming substrate of an aerosol-generating article to generate an aerosol that is inhalable directly into the user's lungs through the user's mouth. The aerosol-generating device may be a holder. The device may be an electrically heated smoking device. The aerosol-generating device may include a housing, circuitry, a power supply, a heating chamber, and a heating element.

[0052] As used herein with reference to the present invention, the term "smoking" used in relation to a device, article, system, substrate or otherwise does not refer to conventional smoking in which the aerosol-forming substrate is completely or at least partially combusted. The aerosol-generating device of the present invention is arranged to heat the aerosol-forming substrate to a temperature that is below the combustion temperature of the aerosol-forming substrate but at or above the temperature at which one or more volatile compounds of the aerosol-forming substrate are released to form an inhalable aerosol.

[0053] The aerosol generating device may include circuitry. The circuitry may include a microprocessor, which may be a programmable microprocessor. The microprocessor may be part of the controller. The circuitry may include additional electronic components. The circuitry may be configured to regulate the supply of power to the heating element. Power may be supplied to the heating element continuously after activation of the aerosol generating device, or may be supplied intermittently, such as on a puff-by-puff basis. Power may be supplied to the heating element in the form of current pulses. The circuitry may be configured to monitor the resistance of the heating element and, preferably, control the supply of power to the heating element based on the resistance of the heating element.

[0054] The aerosol generating device may include a power source, typically a battery, within the body of the aerosol generating device. In one embodiment, the power source is a lithium-ion battery. Alternatively, the power supply may be a nickel-metal hydride battery, a nickel-cadmium battery, or a lithium-based battery such as a lithium-cobalt, lithium-iron-phosphate, lithium titanate, or lithium-polymer battery. Alternatively, the power source may be another form of charge storage device, such as a capacitor. The power source may require recharging and may have a capacity that enables sufficient energy to be stored for one or more use experiences; for example, the power source may have sufficient capacity to continuously generate aerosol for a period of about six minutes or a multiple of six minutes. In another example, the power source may have sufficient capacity to provide a predetermined number of puffs or discontinuous activations of the heating element.

[0055] The cavity of the aerosol generating device may have an open end into which the aerosol generating article is inserted. The open end may be a proximal end. The cavity may have a closed end opposite the open end. The closed end may be the base of the cavity. The closed end may be closed except for providing an air orifice disposed in the base. The base of the cavity may be flat. The base of the cavity may be circular. The base of the cavity may be disposed upstream of the cavity. The open end may be disposed downstream of the cavity. The cavity may have an elongated extension. The cavity may have a longitudinal central axis. The longitudinal direction may be a direction extending along the longitudinal central axis between the open end and the closed end. The longitudinal central axis of the cavity may be parallel to the longitudinal axis of the aerosol generating device.

[0056] The cavity may be configured as a heating chamber. The cavity may have a cylindrical shape. The cavity may have a hollow cylindrical shape. The shape of the cavity may correspond to the shape of the aerosol-generating article to be received in the cavity. The cavity may have a circular cross-section. The cavity may have an elliptical or rectangular cross-section. The cavity may have an inner diameter corresponding to the outer diameter of the aerosol-generating article.

[0057] The airflow channel may pass through the cavity. Ambient air may be drawn into the aerosol-generating device through the airflow channel, into the cavity, and toward the user. A mouthpiece may be positioned downstream of the cavity, or the user may draw directly on the aerosol-generating article. The airflow channel may extend through the mouthpiece.

[0058] In any aspect of the present disclosure, the heating element may comprise a resistive material. Suitable resistive materials include, but are not limited to, semiconductors such as doped ceramics, "conductive" ceramics (such as, for example, molybdenum disilicide), carbon, graphite, metals, metal alloys, and composite materials made from ceramic and metallic materials. Such composite materials may comprise 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 alloys based on nickel, iron, cobalt, stainless steel, and superalloys of iron-manganese-aluminum alloys. In composite materials, the resistive material may optionally be embedded in, encapsulated by, or coated by an insulating material or vice versa, depending on the kinetics of energy transfer and the desired external physicochemical properties.

[0059] As described, in any of the aspects of the present disclosure, the heating element can be part of the aerosol generating device. The aerosol generating device may include an internal heating element or an external heating element or both, where "internal" and "external" are relative to the aerosol-forming substrate. The internal heating element can take any suitable form. For example, the internal heating element can take the form of a heating blade. Alternatively, the internal heater can take the form of a sleeve or substrate with different conductive portions, or a resistive metal tube. Alternatively, the internal heating element can be one or more heating needles or rods extending through the center of the aerosol-forming substrate. Other alternatives include heating wires or filaments, for example, Ni-Cr (nickel-chromium), platinum, tungsten or alloy wires, or heating plates. Alternatively, the internal heating element can be deposited in or on a rigid carrier material. In one such embodiment, the resistive heating element can be formed using a metal with a defined relationship between temperature and resistivity. In such exemplary devices, the metal can be formed as a track on a suitable insulating material (such as a ceramic material) and then sandwiched between another insulating material (such as glass). A heater formed in this manner may be used to both heat and monitor the temperature of the heating element during operation.

[0060] The external heating element can adopt any suitable form.For example, the external heating element can adopt the form of one or more flexible heating foils on a dielectric substrate (for example, polyimide).The flexible heating foil can be shaped to the periphery of the matrix receiving cavity.Alternatively, the external heating element can adopt the form of a metal grid or a plurality of metal grids, a flexible printed circuit board, a molded interconnect device (MID), a ceramic heater, a flexible carbon fiber heater, or can use a coating technology (for example, plasma vapor deposition) to form on a suitable forming substrate.The external heating element can also be formed using a metal with a defined relationship between temperature and resistivity.In such an exemplary device, metal can be formed as a track between two layers of suitable insulating materials.The external heating element formed in this way can be used to both heat and monitor the temperature of the external heating element during operation.

[0061] As an alternative to resistive heating elements, the heating element can be configured as an induction heating element. An induction heating element can include an induction coil and a susceptor. Generally speaking, a susceptor is a material capable of generating heat when penetrated by an alternating magnetic field. When placed in the alternating magnetic field, if the susceptor is conductive, eddy currents are typically induced by the alternating magnetic field. If the susceptor is magnetic, another effect that often contributes to heating is often referred to as hysteresis loss. Hysteresis loss primarily arises from the movement of magnetic domain blocks within the susceptor, as their magnetic orientation aligns with the alternating magnetic induction field. Another effect that contributes to hysteresis loss is when magnetic domains grow or shrink within the susceptor. Generally, all of these changes in the susceptor that occur at the nanometer scale or below are referred to as "hysteresis losses" because they generate heat within the susceptor. Therefore, if the susceptor is both magnetic and conductive, both hysteresis losses and eddy current generation contribute to heating the susceptor. If the susceptor is magnetic but non-conductive, hysteresis losses will be the only means of heating the susceptor when penetrated by the alternating magnetic field. According to the present invention, the susceptor may be electrically conductive or magnetic, or both. The alternating magnetic field generated by one or more induction coils heats the susceptor, which then transfers heat to the aerosol-forming substrate, causing aerosol formation. Heat transfer may be primarily by thermal conduction. This heat transfer is optimal if the susceptor is in close thermal contact with the aerosol-forming substrate.

[0062] As used herein, the term "aerosol-generating article" refers to an article that includes an aerosol-forming substrate that is capable of releasing volatile compounds that can form an aerosol. For example, the aerosol-generating article may be a smoking article that generates an aerosol that can be inhaled directly into the user's lungs through the user's mouth. The aerosol-generating article may be disposable.

[0063] As used herein, the term "aerosol-forming substrate" relates to a substrate capable of releasing one or more volatile compounds that can form an aerosol. Such volatile compounds can be released by heating the aerosol-forming substrate. The aerosol-forming substrate may suitably be part of an aerosol-generating article or a smoking article.

[0064] The aerosol-forming substrate can be a solid aerosol-forming substrate. The aerosol-forming substrate can include both solid components and liquid components. The aerosol-forming substrate can include a tobacco-containing material that contains volatile tobacco flavor compounds released from the substrate when heated. The aerosol-forming substrate can include a non-tobacco material. The aerosol-forming substrate can include an aerosol-forming agent that contributes to the formation of a dense and stable aerosol. Examples of suitable aerosol-forming agents are glycerol and propylene glycol.

[0065] The aerosol-generating substrate preferably comprises: a homogenized tobacco material, an aerosol-forming agent, and water. The aerosol-generating substrate most preferably comprises cut filler and glycerin as an aerosol-forming agent. Providing a homogenized tobacco material can improve aerosol generation, nicotine content, and flavor profile of the aerosol generated during heating of the aerosol-generating article. Specifically, the process for making homogenized tobacco involves grinding tobacco leaves, which more effectively achieves the release of nicotine and flavor when heated.

[0066] The present invention also relates to the use of a moisture-sensitive material in an aerosol-generating article, the moisture-sensitive material's resistance to draw being capable of increasing when subjected to increased humidity, and the moisture-sensitive material's resistance to draw being capable of decreasing when subjected to decreased humidity.

[0067] The present invention also relates to the use of a moisture-sensitive material in an aerosol-generating article, the moisture-sensitive material having a resistance to draw that increases when subjected to increasing humidity and the moisture-sensitive material having a resistance to draw that decreases when subjected to decreasing humidity.

[0068] In particular, the present invention also relates to the use of a moisture-sensitive material as described herein in an aerosol-generating article as described herein.

[0069] 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.

[0070] Example ex1. An aerosol-generating article comprising:

[0071] a substrate portion comprising an aerosol-forming substrate,

[0072] a vent portion downstream of the base portion, wherein the vent portion includes perforations in a sidewall of the vent portion, wherein the perforations are configured to allow ambient air to be drawn into the vent portion through the perforations, and

[0073] A front-rod upstream of the substrate portion, wherein the front-rod comprises a moisture-sensitive material that expands when subjected to increased humidity and contracts when subjected to decreased humidity.

[0074] Example ex2. An aerosol-generating article comprising:

[0075] a substrate portion comprising an aerosol-forming substrate,

[0076] a vent portion downstream of the base portion, wherein the vent portion includes perforations in a sidewall of the vent portion, wherein the perforations are configured to allow ambient air to be drawn into the vent portion through the perforations, and

[0077] a front-rod upstream of the matrix portion, wherein the front-rod comprises a moisture-sensitive material that expands when subjected to increased humidity such that the resistance to draw of the front-rod increases, and contracts when subjected to decreased humidity such that the resistance to draw of the front-rod decreases.

[0078] Example ex3. An aerosol-generating article comprising:

[0079] a substrate portion comprising an aerosol-forming substrate,

[0080] a vent portion downstream of the base portion, wherein the vent portion includes perforations in a sidewall of the vent portion, wherein the perforations are configured to allow ambient air to be drawn into the vent portion through the perforations, and

[0081] A front-rod upstream of the matrix portion, wherein the front-rod includes a moisture-sensitive material whose resistance to draw increases when subjected to increasing humidity and whose resistance to draw decreases when subjected to decreasing humidity.

[0082] Example ex4. An aerosol-generating article comprising:

[0083] a substrate portion comprising an aerosol-forming substrate,

[0084] a vent portion downstream of the base portion, wherein the vent portion includes perforations in a sidewall of the vent portion, wherein the perforations are configured to allow ambient air to be drawn into the vent portion through the perforations, and

[0085] A front-rod upstream of the substrate portion, wherein the front-rod includes a moisture-sensitive material that increases in weight when subjected to increasing humidity and decreases in weight when subjected to decreasing humidity.

[0086] Example ex5. An aerosol-generating article according to any one of the preceding examples, wherein the humidity-sensitive material expands when subjected to increased humidity and contracts when subjected to decreased humidity.

[0087] Example ex6. An aerosol-generating article according to example ex5, wherein when the moisture-sensitive material is subjected to an increase in humidity from 50% relative humidity to 75% relative humidity, the moisture-sensitive material expands by at least 10%, preferably by at least 20%, more preferably by at least 30%, and most preferably by at least 40%.

[0088] Example ex7. An aerosol-generating article according to any of the preceding examples, wherein the resistance to draw of the front rod increases by at least 10%, preferably by at least 20%, more preferably by at least 40%, and most preferably by at least 60% when the moisture-sensitive material is subjected to an increase in humidity from 50% relative humidity to 75% relative humidity.

[0089] Example ex8. An aerosol-generating article according to any of the preceding examples, wherein the moisture-sensitive material comprises one or more materials from the following list: EVA resin; superabsorbent polymer; CMC; polyester; acrylamide; HNBR rubber; acrylate copolymer; polyacrylic acid; polyamide; cross-linked polysaccharide; alginate-coated paper; viscose; acylated soy protein; starch-g-polyacrylonitrile; synthetic hydrogel; polyvinyl alcohol; polyethylene glycol; natural hydrogel; hyaluronic acid; chitosan; heparin; alginate.

[0090] Example ex9. The aerosol-generating article according to any one of the preceding examples, wherein the moisture-sensitive material comprises, preferably consists of, EVA resin, superabsorbent polymer and CMC.

[0091] Example ex10. The aerosol-generating article according to any one of examples ex1 to ex8, wherein the moisture-sensitive material comprises, preferably consists of, cellulose acetate and polyester.

[0092] Example ex11. The aerosol-generating article according to any one of examples ex1 to ex8, wherein the moisture-sensitive material comprises acrylamide and CMC, preferably consists of acrylamide and CMC.

[0093] Example ex12. The aerosol-generating article according to any one of examples ex1 to ex8, wherein the moisture-sensitive material comprises, preferably consists of, HNBR rubber or acrylate copolymer and CMC.

[0094] Example ex13. The aerosol-generating article according to any one of examples ex1 to ex8, wherein the moisture-sensitive material comprises, preferably consists of, polyacrylic acid or polyamide and a filler material.

[0095] Example ex14. The aerosol-generating article according to any one of examples ex1 to ex8, wherein the moisture-sensitive material comprises, preferably consists of, polyvinyl alcohol (PVA)-coated curling paper.

[0096] Example ex15. The aerosol-generating article according to any one of examples ex1 to ex8, wherein the moisture-sensitive material comprises, preferably consists of, 78 gsm curling paper and a polysaccharide.

[0097] Example ex16. The aerosol-generating article according to any one of examples ex1 to ex8, wherein the moisture-sensitive material comprises, preferably consists of, superperga 43gsm curling paper and 16gsm skalax.

[0098] Example ex17. An aerosol-generating article according to any one of the preceding examples, wherein the front-rod has a resistance to draw of between 10 mmWg and 40 mmWg, preferably between 15 mmWg and 30 mmWg at a relative humidity of 50%.

[0099] Example ex18. An aerosol-generating article according to any one of the preceding examples, wherein the front-rod has a resistance to draw of between 20 mmWg and 60 mmWg, preferably between 30 mmWg and 50 mmWg at a relative humidity of 75%.

[0100] Example ex19. An aerosol-generating article according to any one of the preceding examples, wherein the aerosol-generating article has a diameter of between 4.5 mm and 8.0 mm, preferably between 5.0 mm and 7.5 mm, more preferably 7.3 mm.

[0101] Example ex20. An aerosol-generating article according to any one of the preceding examples, wherein the front-rod has a length of between 3 mm and 7 mm, preferably between 4 mm and 6 mm, more preferably 5 mm.

[0102] Example ex21. An aerosol-generating article according to any one of the preceding examples, wherein the substrate portion has a length of between 9.0 mm and 15.0 mm, preferably between 10.5 mm and 13.5 mm, more preferably 12.0 mm.

[0103] Example ex22. An aerosol-generating article according to any one of the preceding examples, wherein the venting portion is configured as a cooling portion having a length between 17 mm and 25 mm, preferably between 19 mm and 22 mm, more preferably 21 mm.

[0104] Example ex23. An aerosol-generating article according to any one of the preceding examples, wherein the ventilation rate of the ventilated portion is between 30% and 50%, preferably between 35% and 45%, more preferably 40%.

[0105] Example ex24. An aerosol-generating article according to any of the preceding examples, wherein the aerosol-generating article further comprises a mouthpiece filter, the mouthpiece filter being downstream of the ventilation portion and preferably having a length between 5 mm and 9 mm, preferably between 6 mm and 8 mm, more preferably 7 mm.

[0106] Example ex25. An aerosol-generating system comprising an aerosol-generating article according to any one of the preceding examples and an aerosol-generating device having a cavity for receiving the aerosol-generating article.

[0107] Example ex26. Use of a moisture-sensitive material in an aerosol-generating article, the moisture-sensitive material having a resistance to draw that increases when subjected to increasing humidity and the moisture-sensitive material having a resistance to draw that decreases when subjected to decreasing humidity.

[0108] Features described with respect to one embodiment may be equally applicable to other embodiments of the invention.

[0109] The present invention will be further described, by way of example only, with reference to the accompanying drawings, in which:

[0110] Figure 1 shows a schematic diagram of an aerosol-generating article according to the present invention;

[0111] Figure 1 An aerosol-generating article is shown having a front-rod 10 , a substrate portion 12 comprising an aerosol-forming substrate, a ventilation portion 14 and a mouthpiece filter 16 .

[0112] The front rod 10 is arranged at the distal end of the aerosol-generating article. The front rod 10 includes a moisture-sensitive material. A paper substrate, a nonwoven material, or a fibrous material can serve as a support material for the moisture-sensitive material. The moisture-sensitive material can be added to the paper substrate, or the paper substrate can be impregnated with the moisture-sensitive material. The moisture-sensitive material can be added to the nonwoven material, or the nonwoven material can be impregnated with the moisture-sensitive material. The moisture-sensitive material can be coated onto the fibrous material.

[0113] The moisture sensitive material expands when subjected to increased humidity. Since the moisture sensitive material of the front rod 10 is in direct contact with the surrounding environment, this will occur under high humidity conditions of the surrounding environment.

[0114] The tipping paper 18 is arranged around the periphery of the moisture-sensitive material of the front stick 10. The tipping paper 18 confines the moisture-sensitive material. As a result, the resistance to draw of the moisture-sensitive material increases. Due to the increased resistance to draw of the moisture-sensitive material, the resistance to draw of the front stick 10 and the resistance to draw of the entire aerosol-generating article increase.

[0115] The tipping paper 18 also connects the front stick 10 to the base portion 12 and the ventilation portion 14. The tipping paper 18 has perforations 20 in the region of the ventilation portion 14, so that ambient air can be drawn into the ventilation portion 14 through the perforations 20. The side walls of the ventilation portion 14, which are preferably made of cardboard, also have corresponding perforations 20, so that ambient air can be drawn into the ventilation portion 14 through the perforations 20.

[0116] The combination of the moisture-sensitive material in the front-stick 10 and the perforations 20 in the ventilation portion 14 helps reduce or prevent undesirable warming of the puff in high-humidity environments. Specifically, in such environments, the resistance to draw of the front-stick 10 will increase as described herein. Consequently, more air will be drawn into the ventilation portion 14 through the perforations 20 compared to low-humidity environments, where the resistance to draw of the front-stick 10 will be lower because the moisture-sensitive material has not yet expanded. More air drawn into the ventilation portion 14 means that the airflow through the aerosol-generating article will be diluted with ambient air and will cool more quickly. This will reduce or prevent undesirable warming sensations during user experience.

[0117] A second tipping paper 22 securing the ventilation portion 14 and the mouthpiece filter 16 may be provided.

[0118] The direction of airflow through the aerosol generating article is Figure 1 Indicated by arrows.

Claims

1. An aerosol-generating article comprising: a substrate portion comprising an aerosol-forming substrate, a vent portion downstream of the base portion, wherein the vent portion includes perforations in a sidewall of the vent portion, wherein the perforations are configured to allow ambient air to be drawn into the vent portion through the perforations, and a front rod upstream of the substrate portion, wherein the front rod comprises a moisture-sensitive material that expands when subjected to increased humidity such that the front rod's resistance to draw increases, and contracts when subjected to decreased humidity such that the front rod's resistance to draw decreases, wherein the moisture-sensitive material expands by at least 10% when subjected to an increase in humidity from 50% relative humidity to 75% relative humidity.

2. An aerosol-generating article according to claim 2, wherein the moisture-sensitive material expands by at least 20%, preferably by at least 30%, more preferably by at least 40% when the moisture-sensitive material is subjected to an increase in humidity from 50% relative humidity to 75% relative humidity.

3. An aerosol-generating article according to any one of the preceding claims, wherein the resistance to draw of the front-rod increases by at least 10%, preferably by at least 20%, more preferably by at least 40%, most preferably by at least 60% when the moisture-sensitive material is subjected to an increase in humidity from 50% relative humidity to 75% relative humidity.

4. An aerosol-generating article according to any one of the preceding claims, wherein the moisture-sensitive material comprises one or more materials from the following list: EVA resin; superabsorbent polymer; carboxymethyl cellulose (CMC); polyester; acrylamide; HNBR rubber; acrylate copolymer; polyacrylic acid; polyamide; cross-linked polysaccharide; alginate-coated paper; viscose; acylated soy protein; starch-g-polyacrylonitrile; synthetic hydrogel; polyvinyl alcohol; polyethylene glycol; natural hydrogel; hyaluronic acid; chitosan; heparin; alginate.

5. An aerosol-generating article according to any one of the preceding claims, wherein the moisture-sensitive material comprises, preferably consists of, EVA resin, superabsorbent polymer and carboxymethyl cellulose (CMC).

6. An aerosol-generating article according to any one of claims 1 to 5, wherein the humidity-sensitive material comprises, preferably consists of, cellulose acetate and polyester.

7. An aerosol-generating article according to any one of claims 1 to 5, wherein the moisture-sensitive material comprises, preferably consists of, acrylamide and carboxymethyl cellulose (CMC).

8. The aerosol-generating article according to any one of claims 1 to 5, wherein the moisture-sensitive material comprises, preferably consists of, HNBR rubber or acrylate copolymer and carboxymethyl cellulose (CMC).

9. An aerosol-generating article according to any preceding claim, wherein the front-rod has a resistance to draw of between 10 mmWg and 40 mmWg, preferably between 15 mmWg and 30 mmWg, at 50% relative humidity.

10. An aerosol-generating article according to any preceding claim, wherein the front-rod has a resistance to draw of between 20 mmWg and 60 mmWg, preferably between 30 mmWg and 50 mmWg at 75% relative humidity.

11. An aerosol-generating article according to any one of the preceding claims, wherein the ventilation ratio of the ventilated portion is between 30% and 50%, preferably between 35% and 45%, more preferably 40%.

12. An aerosol-generating article according to any one of the preceding claims, wherein the aerosol-generating article further comprises a mouthpiece filter, the mouthpiece filter being downstream of the ventilation portion and preferably having a length of between 5 mm and 9 mm, preferably between 6 mm and 8 mm, more preferably 7 mm.

13. An aerosol-generating system comprising an aerosol-generating article according to any preceding claim and an aerosol-generating device having a cavity for receiving the aerosol-generating article.

14. Use of a moisture-sensitive material in an aerosol-generating article, wherein the resistance to draw of the moisture-sensitive material increases when subjected to increasing humidity, and wherein the resistance to draw of the moisture-sensitive material decreases when subjected to decreasing humidity.

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