Aerosol-generating article having humidity-sensitive material

Abstract

The present invention relates to an aerosol-generating article comprising a base portion comprising an aerosol-forming substrate. The aerosol-generating article further comprises a vent portion downstream of the base portion. The vent portion comprises perforations in a sidewall of the vent portion. The perforations are configured to allow ambient air to be drawn into the vent portion through the perforations. The aerosol-generating article further comprises a front plug upstream of the base portion. The front plug comprises a humidity-sensitive material that expands when exposed to an increase in humidity so as to increase the front plug's resistance to withdrawal, and contracts when exposed to a decrease in humidity so as to decrease the front plug's resistance to withdrawal. The present invention further relates to an aerosol-generating system comprising the aerosol-generating article and an aerosol-generating device. The present invention further relates to the use of humidity-sensitive materials in aerosol-generating articles.

Description

[Technical Field]

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

[0002] It is known to provide aerosol-generating articles for generating inhalable vapors. Such aerosol-generating articles can be used in aerosol-generating devices. Such devices 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 a component of the aerosol-generating article. The aerosol-generating article can have a rod shape for insertion into a cavity of the aerosol-generating device, such as a heating chamber. A heating element may be disposed in or around the heating chamber for heating 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 ambient humidity. If ambient humidity is high, the user may experience an undesirable warmth, especially during the first puff.

[0003] It is desirable to have an aerosol-generating article that reduces or prevents the undesirable warm sensation during a puff when the ambient humidity is high.It is desirable to have an aerosol-generating article that reduces or prevents the undesirable warm sensation during the first puff when the ambient humidity is high.It is desirable to have an aerosol-generating article that has the ability to deliver a more uniform aerosol when the ambient humidity is high. Summary of the Invention

[0004] According to one embodiment of the present invention, there is provided an aerosol-generating article that may include a base portion comprising an aerosol-forming substrate. The aerosol-generating article may further include a vent portion downstream of the base portion. The vent portion may include perforations in a sidewall of the vent portion. The perforations may be configured to allow ambient air to be drawn into the vent portion through the perforations. The aerosol-generating article may further include a front plug upstream of the base portion. The front plug may comprise a humidity-sensitive material that expands when exposed to an increase in humidity to increase the withdrawal resistance of the front plug and contracts when exposed to a decrease in humidity to decrease the withdrawal resistance of the front plug.

[0005] According to one embodiment of the present invention, an aerosol-generating article is provided, comprising a base portion including an aerosol-forming substrate. The aerosol-generating article further comprises a vent portion downstream of the base portion. The vent portion comprises perforations in a sidewall of the vent portion. The perforations are configured to allow ambient air to be drawn into the vent portion through the perforations. The aerosol-generating article further comprises a front plug upstream of the base portion. The front plug comprises a humidity-sensitive material that expands when exposed to an increase in humidity so as to increase the withdrawal resistance of the front plug, and contracts when exposed to a decrease in humidity so as to decrease the withdrawal resistance of the front plug.

[0006] Increasing the withdrawal resistance of the front plug in a relatively humid ambient environment can increase the withdrawal resistance of the entire aerosol-generating article. Increasing the withdrawal resistance of the entire aerosol-generating article may be desirable in a relatively humid ambient environment. In particular, increasing the withdrawal resistance of the entire aerosol-generating article can be beneficial in situations where a user draws less aerosol into their mouth during the first puff. This can reduce the undesirable warmth felt when ambient humidity is high. Particularly preferably, providing a ventilation section with perforations in the sidewall of the ventilation section can synergistically interact with the increased withdrawal resistance of the upstream humidity-sensitive material. More specifically, when the withdrawal resistance of the humidity-sensitive material increases, more ambient air is drawn into the aerosol-generating article in the ventilation section downstream of the humidity-sensitive material. This can dilute the generated aerosol. This can cool the generated aerosol. The aerosol is generated with a high ratio of ambient air to air drawn throughout the aerosol-generating article, providing a milder experience for the user, especially during the first puff.

[0007] Reducing the withdrawal resistance of the front plug in a relatively low-humidity ambient environment can reduce the withdrawal resistance of the entire aerosol-generating article. In this way, the user experience can be optimized for the humidity of the current ambient environment. More specifically, in low-humidity environments, less ambient air is drawn into the aerosol-generating article through the perforations in the ventilation portion. Therefore, the user will experience a more desirable and intense experience due to the lower ratio of ambient air to air drawn throughout the aerosol-generating article.

[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 in the ventilation zone to air drawn throughout the aerosol-generating article in response to the humidity of the surrounding environment, thereby reducing or preventing the user from experiencing undesirable warmth during a puff when the ambient humidity is high.

[0009] The humidity-sensitive material may be placed in direct fluid contact with the ambient environment. At least the distal end surface of the humidity-sensitive material may feel undesirably warm when the ambient humidity is high. Thus, the humidity-sensitive material may be exposed to ambient humidity. Depending on the humidity of the ambient environment, the humidity-sensitive material may absorb more or less water from the ambient environment. This may result in the humidity-sensitive material expanding in the case of a humid ambient environment.

[0010] A humidity-sensitive material may expand when exposed to increased humidity and contract when exposed to decreased humidity. Alternatively, a humidity-sensitive material may expand when exposed to increased humidity and not expand when exposed to decreased humidity. Alternatively, a humidity-sensitive material may expand when exposed to increased humidity and not change when exposed to decreased humidity.

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

[0012] The property of humidity-sensitive materials to expand when exposed to relatively high humidity can result in increased resistance to withdrawal due to the humidity-sensitive material becoming trapped within the aerosol-generating article. More specifically, tipping paper can be placed around the humidity-sensitive material to form a front plug. This tipping paper can prevent radial expansion of the humidity-sensitive material. Therefore, the expansion of the humidity-sensitive material can be internal expansion that reduces the ability of air to flow through the humidity-sensitive material.

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

[0014] The expansion of the humidity-sensitive material may be an observable property of the material when the humidity-sensitive material is unconfined. As mentioned herein, the humidity-sensitive material may be confined within the aerosol-generating article via tipping paper surrounding the humidity-sensitive material, thereby forming a front plug. The expansion may reduce the cross-section of the flow through the humidity-sensitive material, thereby reducing the humidity-sensitive material's ability to allow airflow through the material.

[0015] The cross section of flow through the humidity sensitive material may decrease by at least 10%, preferably at least 20%, more preferably at least 30%, and most preferably at least 40% when the humidity sensitive material is subjected to a humidity increase from 50% relative humidity to 75% relative humidity.

[0016] Instead of describing the property of the front plug that increases its resistance to withdrawal under high humidity conditions and decreases its resistance to withdrawal under low humidity conditions by the expansion / contraction of the humidity-sensitive material, the weight gain / loss of the humidity-sensitive material can be used. More specifically, the humidity-sensitive material absorbs water under high humidity conditions, increasing its weight in the process. The added weight reduces the humidity-sensitive material's ability to allow airflow through it. Thus, the weight gain due to water absorption increases its resistance to withdrawal. Therefore, measuring the weight difference can indicate the expansion or contraction of the humidity-sensitive material.

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

[0018] The moisture sensitive material may include 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 humidity-sensitive material may comprise, or preferably consist of, EVA resin, a superabsorbent polymer, and CMC. The humidity-sensitive material may comprise, or consist of, EVA resin, a superabsorbent polymer, and CMC, as described in JP2014198760A.

[0020] The moisture-sensitive material may comprise, or preferably consist of, acrylamide and CMC. The moisture-sensitive material may comprise, or consist of, acrylamide and CMC, as described in WO2016163160A1.

[0021] The moisture-sensitive material may comprise, or 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 / 0084550 A1.

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

[0023] The moisture-sensitive material may comprise, or preferably consist of, a cross-linked polysaccharide. The moisture-sensitive material may comprise, or consist of, a cross-linked polysaccharide, as described in EP0566118A1. https: / / worldwide.espacenet.com / patent / search?q=pn%3DEP0566118A1

[0024] The moisture sensitive material may comprise, or preferably consist of, polyvinyl alcohol (PVA) coated crimped paper.

[0025] The moisture sensitive material may comprise, or preferably consist of, 78 gsm crimped paper and polysaccharides.

[0026] The moisture sensitive material may comprise, or preferably consist of, SuperPerga 43 gsm crimped paper and 16 gsm Skalax.

[0027] The front plug may comprise a paper matrix. A humidity-sensitive material as described herein may be added to the paper matrix. The paper matrix may be impregnated with a humidity-sensitive material as described herein. Preferably, up to 20% by weight of humidity-sensitive material may be added to the paper matrix. Preferably, the paper matrix may be impregnated with up to 20% by weight of humidity-sensitive material. Particularly preferably, 5% to 10% by weight of humidity-sensitive material may be added to the paper matrix. Particularly preferably, the paper matrix may be impregnated with 5% to 10% by weight of humidity-sensitive material.

[0028] The front plug 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, 10% to 20% by weight of the moisture sensitive material may be added to the nonwoven material. Particularly preferably, the nonwoven material may be impregnated with 10% to 20% by weight of the moisture sensitive material.

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

[0030] One or more of a paper matrix, a nonwoven material, and a fibrous material can function as a support material for the moisture sensitive material.

[0031] The front plug may have a withdrawal resistance of 10 mmWg to 40 mmWg, preferably 15 mmWg to 30 mmWg at 50% relative humidity.

[0032] The front plug may have a withdrawal resistance of 20 mmWg to 60 mmWg, preferably 30 mmWg to 50 mmWg at 75% relative humidity.

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

[0034] The front plug may have a length of 3mm to 7mm, preferably 4mm to 6mm, more preferably 5mm.

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

[0036] The ventilation portion may be configured as a cooling portion having a length of 17 mm to 25 mm, preferably 19 mm to 22 mm, more preferably 21 mm.

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

[0038] The perforations may be configured as described in PCT / EP2022 / 073899. In particular, the ventilation portion of the present application may correspond to the ventilation zones described in PCT / EP2022 / 073899 with corresponding perforations described in PCT / EP2022 / 073899.

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

[0040] The structural integrity of the vent portion may be promoted by a cardboard sidewall. The cardboard sidewall may be circular. The vent portion may not include any additional elements other than the cardboard sidewall and potentially tipping paper surrounding the periphery of the cardboard sidewall. The vent portion may include tipping paper surrounding the periphery of the cardboard sidewall. The vent portion may consist of cardboard. The vent portion may consist of cardboard and tipping paper, as well as perforations through the sidewall 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, holding the respective elements of the aerosol-generating article together. In particular, the tipping paper may extend downstream toward the mouthpiece filter, holding the ventilation portion and the mouthpiece filter together. The tipping element may extend upstream toward the base portion, holding the ventilation portion and the base portion together. The tipping paper may be wrapped around one or more of the ventilation portion, mouthpiece filter, and base portion.

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

[0043] The resistance to withdrawal of the aerosol-generating article may be the sum of the individual resistances to withdrawal of the individual elements of the aerosol-generating article. In other words, the resistance to withdrawal of the aerosol-generating article may be the resistance to withdrawal of the front plug + the resistance to withdrawal of the base portion + the resistance to withdrawal of the cooling element + the resistance to withdrawal of the vent portion + the resistance to withdrawal of the mouthpiece filter + the resistance to withdrawal of any additional elements of the aerosol-generating article that contribute to the resistance to withdrawal. Because the vent portion is hollow, the resistance to withdrawal of the vent portion may be zero or near zero.

[0044] The aerosol-forming substrate may contain a cut filler. The aerosol-forming substrate may contain 16% to 20% by weight of aerosol formers, preferably 17% to 19% by weight of aerosol formers, and more preferably 18% by weight of aerosol formers.

[0045] The aerosol-forming substrate may have a bulk density of 0.28 mg / mm 3 to 0.36 mg / mm 3 , preferably 0.30 mg / mm 3 to 0.34 mg / mm 3 , more preferably 0.32 mg / mm 3 .

[0046] The base portion may have a pull-out resistance of 24 mmWG to 36 mmWG, preferably 27 mmWG to 33 mmWG, and more preferably 30 mmWG.

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

[0048] The present invention further relates to an aerosol generation 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," "downstream," and "upstream" are used to describe the relative location of a component or portion of a component of an aerosol-generating device or aerosol-generating article with respect to the direction in which a user draws on the aerosol-generating device or aerosol-generating article during use.

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

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

[0052] As used herein in relation to the present invention, the term "smoking", 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 below the combustion temperature of the aerosol-forming substrate but above the temperature at which one or more volatile compounds of the aerosol-forming substrate are released, in order to form an inhalable aerosol.

[0053] The aerosol generating device may comprise an electrical circuit. The electrical circuit may comprise a microprocessor, which may be a programmable microprocessor. The microprocessor may be part of a controller. The electrical circuit may comprise further electronic components. The electrical circuit may be configured to regulate the supply of power to the heating element. Power may be supplied to the heating element continuously following activation of the aerosol generating device, or may be supplied intermittently, such as with each puff. Power may be supplied to the heating element in the form of current pulses. The electrical circuit may be configured to monitor the electrical resistance of the heating element and to control the supply of power to the heating element, preferably depending on the electrical resistance of the heating element.

[0054] The aerosol generating device may include a power source, typically a battery, within the main body of the aerosol generating device. In one embodiment, the power source is a lithium-ion battery. Alternatively, the power source may be a nickel-metal hydride battery, a nickel-cadmium battery, or a lithium-based battery (e.g., a lithium-cobalt battery, a lithium iron phosphate battery, a lithium titanate battery, or a 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 allows for storage of sufficient energy for one or more use experiences; for example, the power source may have a capacity sufficient to continuously generate aerosol for a period of about six minutes, or for a period of a multiple of six minutes. In another example, the power source may have a capacity sufficient to provide a predetermined number of puffs or discontinuous activation 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 a base of the cavity. The closed end may be closed except for an air opening disposed within 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 axis may be a direction extending between the open end and the closed end along the longitudinal central axis. 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 cavity may have a shape corresponding to the shape of the aerosol-generating article to be received within 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] An airflow channel may extend through the cavity. Ambient air may be drawn through the airflow channel into the aerosol-generating device, into the cavity, and toward the user. Downstream of the cavity, a mouthpiece may be disposed, or the user may inhale the aerosol-generating article directly. The airflow channel may extend through the mouthpiece.

[0058] In any aspect of the present disclosure, the heating element may include an electrically resistive material. Suitable electrically resistive materials include, but are not limited to, semiconductors such as doped ceramics, "conductive" ceramics (e.g., molybdenum disilicide), carbon, graphite, metals, alloys, and composites made of ceramic and metallic materials. Such composites may include doped or undoped ceramics. An example of a suitable doped ceramic is 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, cobalt-containing, chromium-containing, aluminum-containing, titanium-containing, zirconium-containing, hafnium-containing, niobium-containing, molybdenum-containing, tantalum-containing, tungsten-containing, tin-containing, gallium-containing, manganese-containing, gold-containing, and iron-containing alloys, as well as nickel-, iron-, cobalt-, and stainless steel-based superalloys, Timetal®, and iron-manganese-aluminum-based alloys. In composite materials, the electrically resistive material may optionally be embedded in, encapsulated in, or coated with the insulating material, or vice versa, depending on the required energy transfer kinetics and 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 can include an internal or external heating element, or both, with "internal" and "external" referring 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 casing or substrate having different conductive portions or an electrically resistive metal tube. Alternatively, the internal heating element can be one or more heated needles or rods that pass through the center of the aerosol-forming substrate. Other alternatives include a heated wire or filament, such as Ni-Cr (nickel-chromium), platinum, tungsten, or alloy wire or heating plate. Optionally, the internal heating element can be disposed within or on a rigid carrier material. In one such embodiment, the electrically resistive heating element can be formed using a metal with a well-defined relationship between temperature and resistivity. In such an exemplary device, the metal may be formed as a track on a suitable insulating material, such as a ceramic material, and then sandwiched in another insulating material, such as glass. The heater thus formed may be used to both heat the heating element and monitor its temperature during operation.

[0060] The external heating element may take any suitable form. For example, the external heating element may take the form of one or more flexible heating foils on a dielectric substrate such as polyimide. The flexible heating foil may be shaped to fit around the substrate-receiving cavity. Alternatively, the external heating element may take the form of a metal grid, a flexible printed circuit board, a molded interconnect device (MID), a ceramic heater, a flexible carbon fiber heater, or may be formed using a coating technique such as plasma deposition on a suitably shaped substrate. The external heating element may also be formed using a metal having a well-defined relationship between temperature and resistivity. In such an exemplary device, the metal may be formed as a track between two layers of suitable insulating material. The external heating element thus formed may be used both to heat the external heating element and to monitor the temperature of the external heating element during operation.

[0061] As an alternative to an electrically resistive heating element, the heating element may be configured as an induction heating element. The induction heating element may include an induction coil and a susceptor. Generally, the susceptor is a material capable of generating heat when penetrated by an alternating magnetic field. When placed within the alternating magnetic field, if the susceptor is conductive, the alternating magnetic field typically induces eddy currents. If the susceptor is magnetic, another effect that typically contributes to heating is commonly referred to as hysteresis loss. Hysteresis loss occurs primarily due to the movement of magnetic domain blocks within the susceptor as their magnetic orientation aligns with the alternating induced magnetic field. Another effect that contributes to hysteresis loss is when magnetic domains expand or contract within the susceptor. Generally, all of these changes occurring within the susceptor at the nanoscale or below generate heat within the susceptor, hence the term "hysteresis loss." Thus, if the susceptor is both magnetic and conductive, both hysteresis loss and the generation of eddy currents will contribute to the heating of the susceptor. If the susceptor is magnetic but not conductive, hysteresis loss will be the only means by which the susceptor will heat when penetrated by an alternating magnetic field. According to the present invention, the susceptor can be conductive or magnetic, or both conductive and magnetic. The alternating magnetic field generated by one or several induction coils heats the susceptor, which then transfers heat to the aerosol-forming substrate, thereby forming the aerosol. Heat transfer can be primarily by conduction. Such heat transfer is best when the susceptor is in intimate thermal contact with the aerosol-forming substrate.

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

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

[0064] The aerosol-forming substrate may be a solid aerosol-forming substrate. The aerosol-forming substrate may include both solid and liquid components. The aerosol-forming substrate may include a tobacco-containing material containing volatile tobacco flavor compounds that are released from the substrate upon heating. The aerosol-forming substrate may include a non-tobacco material. The aerosol-forming substrate may include an aerosol former that facilitates the formation of a dense and stable aerosol. Examples of suitable aerosol formers are glycerin and propylene glycol.

[0065] The aerosol-generating substrate preferably comprises a homogenized tobacco material, an aerosol former, and water. Most preferably, the aerosol-generating substrate comprises a cut filler and glycerin as the aerosol former. Providing a homogenized tobacco material may improve aerosol generation and the nicotine content and flavor profile of the aerosol generated during heating of the aerosol-generating article. Specifically, the process of making homogenized tobacco involves grinding tobacco leaves, which allows for more efficient release of nicotine and flavor upon heating.

[0066] The present invention further relates to the use of humidity sensitive materials in aerosol-generating articles that can increase their resistance to withdrawal when exposed to increased humidity and decrease their resistance to withdrawal when exposed to decreased humidity.

[0067] The present invention further relates to the use of humidity sensitive materials in aerosol-generating articles that exhibit an increased resistance to withdrawal when exposed to increased humidity and a decreased resistance to withdrawal when exposed to decreased humidity.

[0068] In particular, the present invention further relates to the use of the humidity sensitive materials described herein in the aerosol-generating articles described herein. [Example]

[0069] The following provides a non-exhaustive list of non-limiting examples, any one or more of the features of which may be combined with any one or more features of any other example, embodiment, or aspect described herein.

[0070] Example 1 An aerosol-generating article comprising: a substrate portion comprising an aerosol-forming substrate; a vent portion downstream of the base portion, the vent portion including perforations in a sidewall of the vent portion, the perforations configured to allow ambient air to be drawn into the vent portion through the perforations; an anterior plug upstream of the base portion, the anterior plug comprising a humidity-sensitive material that expands when exposed to an increase in humidity and contracts when exposed to a decrease in humidity. Example 2. An aerosol-generating article comprising: a substrate portion comprising an aerosol-forming substrate; a vent portion downstream of the base portion, the vent portion including perforations in a sidewall of the vent portion, the perforations configured to allow ambient air to be drawn into the vent portion through the perforations; an aerosol-generating article comprising a front plug upstream of the base portion, the front plug comprising a humidity-sensitive material that expands when exposed to an increase in humidity so that the front plug's resistance to withdrawal increases, and that contracts when exposed to a decrease in humidity so that the front plug's resistance to withdrawal decreases. Example 3 An aerosol-generating article comprising: a substrate portion comprising an aerosol-forming substrate; a vent portion downstream of the base portion, the vent portion including perforations in a sidewall of the vent portion, the perforations configured to allow ambient air to be drawn into the vent portion through the perforations; an aerosol-generating article comprising a front plug upstream of the base portion, the front plug comprising a humidity-sensitive material that increases its resistance to withdrawal when exposed to an increase in humidity and decreases its resistance to withdrawal when exposed to a decrease in humidity. Example 4. An aerosol-generating article comprising: a substrate portion comprising an aerosol-forming substrate; a vent portion downstream of the base portion, the vent portion including perforations in a sidewall of the vent portion, the perforations configured to allow ambient air to be drawn into the vent portion through the perforations; an anterior plug upstream of the base portion, the anterior plug comprising a humidity-sensitive material that increases in weight when exposed to an increase in humidity and decreases in withdrawn weight when exposed to a decrease in humidity. Example 5. 5. An aerosol-generating article according to any one of Examples 1 to 4, wherein the humidity-sensitive material expands when exposed to an increase in humidity and contracts when exposed to a decrease in humidity. Example 6 6. The aerosol-generating article of Example 5, wherein the humidity-sensitive material expands by at least 10%, preferably at least 20%, more preferably at least 30%, and most preferably at least 40% when the humidity-sensitive material is exposed to an increase in humidity from 50% relative humidity to 75% relative humidity. Example 7 An aerosol-generating article as described in any of Examples 1 to 6, wherein the withdrawal resistance of the front plug increases by at least 10%, preferably at least 20%, more preferably at least 40%, and most preferably at least 60% when the humidity-sensitive material is exposed to an increase in humidity from 50% relative humidity to 75% relative humidity. Example 8 8. The aerosol-generating article of any one of Examples 1 to 7, wherein the humidity-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, and alginate. Example 9. An aerosol-generating article according to any one of Examples 1 to 8, wherein the moisture-sensitive material comprises, or preferably consists of, EVA resin, superabsorbent polymer, and CMC. Example 10. An aerosol-generating article according to any one of Examples 1 to 8, wherein the moisture-sensitive material comprises, or preferably consists of, cellulose acetate and polyester. Example 11 An aerosol-generating article according to any one of Examples 1 to 8, wherein the moisture-sensitive material comprises, or preferably consists of, acrylamide and CMC. Example 12 An aerosol-generating article according to any one of Examples 1 to 8, wherein the humidity-sensitive material comprises, or preferably consists of, HNBR rubber and an acrylate copolymer. Example 13 An aerosol-generating article according to any one of Examples 1 to 8, wherein the moisture-sensitive material comprises, or preferably consists of, polyacrylic acid or polyamide and a filler material. Example 14. 9. An aerosol-generating article according to any one of Examples 1 to 8, wherein the humidity-sensitive material comprises, or preferably consists of, crimped paper coated with polyvinyl alcohol (PVA). Example 15. An aerosol-generating article according to any one of Examples 1 to 8, wherein the moisture-sensitive material comprises, or preferably consists of, 78 gsm crimped paper and polysaccharides. Example 16. An aerosol-generating article according to any one of Examples 1 to 8, wherein the moisture-sensitive material comprises, or preferably consists of, 43 gsm crimped paper and 16 gsm Skalax. Example 17. An aerosol-generating article according to any one of Examples 1 to 16, wherein the front plug has a withdrawal resistance of 10 mmWg to 40 mmWg, preferably 15 mmWg to 30 mmWg, at a relative humidity of 50%. Example 18. An aerosol-generating article according to any one of Examples 1 to 17, wherein the front plug has a withdrawal resistance of 20 mmWg to 60 mmWg, preferably 30 mmWg to 50 mmWg, at a relative humidity of 75%. Example 19. 19. An aerosol-generating article according to any one of Examples 1 to 18, wherein the aerosol-generating article has a diameter of 4.5 mm to 8.0 mm, preferably 5.0 mm to 7.5 mm, more preferably 7.3 mm. Example 20. 20. An aerosol-generating article according to any one of Examples 1 to 19, wherein the front plug has a length of 3 mm to 7 mm, preferably 4 mm to 6 mm, more preferably 5 mm. Example 21. 21. An aerosol-generating article according to any one of Examples 1 to 20, wherein the base portion has a length of 9.0 mm to 15.0 mm, preferably 10.5 mm to 13.5 mm, more preferably 12.0 mm. Example 22. An aerosol-generating article according to any one of Examples 1 to 21, wherein the ventilation portion is configured as a cooling portion having a length of 17 mm to 25 mm, preferably 19 mm to 22 mm, more preferably 21 mm. Example 23. An aerosol-generating article according to any one of Examples 1 to 22, wherein the ventilation portion has a ventilation rate of 30% to 50%, preferably 35% to 45%, and more preferably 40%. Example 24. An aerosol-generating article according to any one of Examples 1 to 23, further comprising a mouthpiece filter downstream of the ventilation portion, the mouthpiece filter preferably having a length of 5 mm to 9 mm, preferably 6 mm to 8 mm, more preferably 7 mm. Example 25. An aerosol generating system comprising the aerosol-generating article according to any one of Examples 1 to 24 and an aerosol generating device having a cavity for receiving the aerosol-generating article. Example 26. The use of a humidity-sensitive material in an aerosol-generating article, which exhibits increased resistance to withdrawal when exposed to an increase in humidity and decreased resistance to withdrawal when exposed to a decrease in humidity.

[0071] Features described with respect to one embodiment may be equally applied to other embodiments of the invention.

[0072] The invention will now be further described, by way of example only, with reference to the accompanying drawings in which: [Brief explanation of the drawings]

[0073] [Figure 1] FIG. 1 shows a diagram of an aerosol-generating article according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0074] FIG. 1 shows an aerosol-generating article having a front plug 10 , a substrate portion 12 comprising an aerosol-forming substrate, a ventilation portion 14 , and a mouthpiece filter 16 .

[0075] The front plug 10 is disposed at the distal end of the aerosol-generating article. The front plug 10 contains a humidity-sensitive material. A paper matrix, a nonwoven material, or a fibrous material can serve as a support material for the humidity-sensitive material. The humidity-sensitive material can be added to a paper matrix, or the paper matrix can be impregnated with the humidity-sensitive material. The humidity-sensitive material can be added to a nonwoven material, or the nonwoven material can be impregnated with the humidity-sensitive material. The humidity-sensitive material can be coated on a fibrous material.

[0076] The moisture sensitive material expands when exposed to increased humidity, which occurs in humid conditions in the ambient environment because the moisture sensitive material of the front plug 10 is in direct contact with the ambient environment.

[0077] Tipping paper 18 is disposed to surround the moisture-sensitive material of front plug 10. Tipping paper 18 confines the moisture-sensitive material. As a result, the resistance to withdrawal of the moisture-sensitive material increases. This increases the resistance to withdrawal of the moisture-sensitive material, thereby increasing the resistance to withdrawal of front plug 10 and the entire aerosol-generating article.

[0078] Tipping paper 18 also connects front plug 10 with base portion 12 and vent portion 14. Tipping paper 18 has perforations 20 in the area of ​​vent portion 14 to allow ambient air to be drawn into vent portion 14 through perforations 20. The side walls of vent portion 14, preferably made of cardboard, also have corresponding perforations 20, allowing ambient air to be drawn into vent portion 14 through perforations 20.

[0079] The combination of the humidity-sensitive material in the front plug 10 and the perforations 20 in the ventilation portion 14 facilitates reducing or preventing undesirable warm puffs in high humidity environments. In particular, as described herein, in such environments, the front plug 10's resistance to withdrawal increases. As a result, more air is drawn into the ventilation portion 14 through the perforations 20 compared to low humidity environments, where the humidity-sensitive material is not expanding and therefore the front plug 10's resistance to withdrawal is lower. More air drawn into the ventilation portion 14 means that the airflow through the aerosol-generating article is diluted with ambient air and cooled more rapidly. This reduces or prevents the undesirable warm sensation experienced by the user.

[0080] A second tipping paper 22 may also be provided to secure the ventilation portion 14 and mouthpiece filter 16.

[0081] The direction of airflow through the aerosol-generating article is indicated by arrows in FIG.

Claims

1. An aerosol-generating article comprising: a substrate portion comprising an aerosol-forming substrate; a vent portion downstream of the base portion, the vent portion including perforations in a sidewall of the vent portion, the perforations configured to allow ambient air to be drawn into the vent portion through the perforations; and a front plug upstream of the base portion, the front plug comprising a humidity-sensitive material that expands when exposed to an increase in humidity so that the front plug's resistance to withdrawal increases and contracts when exposed to a decrease in humidity so that the front plug's resistance to withdrawal decreases, wherein the humidity-sensitive material expands by at least 10% when exposed to an increase in humidity from 50% relative humidity to 75% relative humidity.

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

3. 3. An aerosol-generating article according to claim 1, wherein the resistance to withdrawal of the front plug increases by at least 10%, preferably at least 20%, more preferably at least 40%, and most preferably at least 60% when the humidity-sensitive material is exposed to an increase in humidity from 50% relative humidity to 75% relative humidity.

4. 4. The aerosol-generating article of claim 1, wherein the humidity-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. 5. An aerosol-generating article according to any one of claims 1 to 4, wherein the humidity-sensitive material comprises, or preferably consists of, EVA resin, superabsorbent polymer, and carboxymethyl cellulose (CMC).

6. 6. An aerosol-generating article according to any preceding claim, wherein the humidity-sensitive material comprises, or preferably consists of, cellulose acetate and polyester.

7. 6. An aerosol-generating article according to any preceding claim, wherein the humidity-sensitive material comprises, or preferably consists of, acrylamide and carboxymethylcellulose (CMC).

8. 6. An aerosol-generating article according to any preceding claim, wherein the humidity-sensitive material comprises, or preferably consists of, HNBR rubber or an acrylate copolymer and carboxymethyl cellulose (CMC).

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

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

11. 11. The aerosol-generating article according to claim 1, wherein the ventilation portion has a permeability of 30% to 50%, preferably 35% to 45%, and more preferably 40%.

12. An aerosol-generating article according to any one of claims 1 to 11, further comprising a mouthpiece filter downstream of the ventilation portion, the mouthpiece filter preferably having a length of 5 mm to 9 mm, preferably 6 mm to 8 mm, more preferably 7 mm.

13. An aerosol generating system comprising: an aerosol-generating article according to any one of claims 1 to 12; and an aerosol generating device having a cavity for receiving the aerosol-generating article.

14. 1. Use of a humidity sensitive material, wherein in the aerosol-generating article, the resistance to withdrawal of the humidity sensitive material increases when exposed to an increase in humidity, and the resistance to withdrawal of the humidity sensitive material decreases when exposed to a decrease in humidity.

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