EP4704612A1

EP4704612A1 - Aerosol-generating article comprising a carboxylic acid

Info

Publication number: EP4704612A1
Application number: EP24723155.8A
Authority: EP
Inventors: Guillaume Bastien BAUR
Original assignee: Philip Morris Products SA
Current assignee: Philip Morris Products SA
Priority date: 2023-05-03
Filing date: 2024-05-02
Publication date: 2026-03-11
Also published as: CN121001591A; WO2024227849A1; KR20260003783A

Abstract

There is provided an aerosol-generating article (10) for generating an inhalable aerosol upon heating. The aerosol-generating article (10) comprises: an aerosol-generating element (12) comprising a nicotine-containing aerosol-generating substrate; and a downstream section (17) located downstream of the aerosol generating element (12). The downstream section (17) comprises a carboxylic acid selected from the group consisting of citric acid, benzoic acid, fumaric acid, lactic acid and combinations thereof.

Description

AEROSOL-GENERATING ARTICLE COMPRISING A CARBOXYLIC ACID

The present invention relates to an aerosol-generating article comprising an aerosolgenerating element and adapted to produce an inhalable aerosol upon heating. In particular, the present invention relates to an aerosol-generating article comprising an aerosolgenerating element comprising a nicotine-containing aerosol-generating substrate. Aspects of the disclosure further relate to an aerosol-generating system comprising an electrically operated aerosol-generating device that is used to heat the aerosol-generating article of the type set out above.

Aerosol-generating articles in which an aerosol-generating element comprising an aerosol-generating substrate, such as a tobacco-containing substrate, is heated rather than combusted, are known in the art. Typically, in such heated smoking articles an aerosol is generated by the transfer of heat from a heat source to a physically separate aerosolgenerating substrate or material, which may be located in contact with, within, around, or downstream of the heat source.

Several aerosol-generating devices for heating aerosol-generating articles have been disclosed in the art. Such devices include, for example, electrically heated aerosol-generating devices in which an aerosol is generated by the transfer of heat from one or more electrical heater elements of the aerosol-generating device to the aerosol-generating element of an aerosol-generating article. For example, electrically heated devices have been proposed that comprise an internal heater blade which is adapted to be inserted into the substrate. As an alternative, inductively heat able consumables including a substrate and a susceptor arranged within the substrate have also been proposed. Another alternative could be an electrically heated devices including an external heater heating the substrate from the outer periphery of the consumable, said external heater could be resistive or inductive. To this purpose, the aerosol-generating article is partially received within a heating cavity of the aerosol-generating device, such that an upstream end of the aerosol-generating article is inserted into the cavity whereas a downstream end of the aerosol-generating article projects out of the cavity.

Substrates for heated consumables have, in the past, typically been produced using randomly oriented shreds, strands, or strips of tobacco material or cut filler. As an alternative, rods for heated consumables have been proposed, for example in international patent application WO-A-2012/164009, that are formed from gathered sheets of tobacco material (cast leaf) or from a gathered nicotine containing film or gel. Alternative rods for heated consumables are known from international patent application WO-A-2011/101164. These rods are formed from strands of homogenized tobacco material, which may be formed by casting, rolling, calendaring or extruding a mixture comprising particulate tobacco and at least one aerosol former to form a sheet of homogenized tobacco material. In alternative embodiments, the rods may also be formed from strands of homogenized tobacco material obtained by extruding a mixture comprising particulate tobacco and at least one aerosol former to form continuous lengths of homogenized tobacco material. Solid, nicotine-containing, nontobacco substrates are also known. WO-A-2015/082652, for example, describes an aerosolgenerating rod comprising a gathered sheet of non-tobacco material circumscribed by a wrapper. The sheet of non-tobacco material is textured or crimped and comprises a sorbent substrate, a nicotine salt, and an aerosol-former.

During use of the aerosol-generating article, volatile compounds are released from the aerosol-generating substrate by heat transfer from the heat source and are entrained in air drawn through the aerosol-generating article. As the released compounds cool, they condense to form an aerosol.

In aerosol-generating articles wherein the aerosol-generating substrate contains tobacco or nicotine in some other form, the aerosol may induce a low to moderate harshness response in the throat and a perceived warmth or strength in the chest of the adult smoker. The harshness of the aerosol, which is understood as the sensation experienced in the throat of the adult smoker, and the strength of the aerosol, which is typically understood as the sensation experienced in the chest of the adult smoker, may vary based on the nature and composition of the aerosol-generating substrate from which the aerosol is formed, including but not limited to the concentration of nicotine in the aerosol. In some cases, higher levels of nicotine delivery may be associated with an increased harshness, which can cause an uncomfortable feeling in the throat of the consumer.

Therefore, it would be desirable to provide a new and improved aerosol-generating article adapted to deter or at least attenuate such uncomfortable sensation without significantly impacting the aerosol delivery levels and taste.

The present disclosure relates to an aerosol-generating article for generating an inhalable aerosol upon heating.

The aerosol-generating article may comprise an aerosol generating element.

The aerosol-generating element may comprise a nicotine-containing aerosolgenerating substrate.

The nicotine-containing aerosol-generating substrate may be a solid nicotine- containing aerosol-generating substrate. The aerosol-generating element may comprise a downstream section located downstream of the aerosol-generating element.

The downstream section of the aerosol-generating article may comprise a carboxylic acid. The carboxylic acid may be selected from the group consisting of citric acid, benzoic acid, fumaric acid, lactic acid and combinations thereof.

For example, the aerosol-generating article may comprise a mouthpiece at a downstream section of the aerosol-generating article, such as a mouthpiece comprising a segment of filtration material, and the carboxylic acid may be provided at a location within the mouthpiece.

The present disclosure also relates to an aerosol-generating system comprising an electrically operated aerosol-generating device and an aerosol-generating article comprising an aerosol generating element comprising an aerosol-generating substrate.

The aerosol-generating device may comprise means to heat the aerosol-generating substrate to a temperature sufficient to generate an aerosol from the aerosol generating substrate.

According to a first aspect of the present invention, there is provided an aerosolgenerating article for generating an inhalable aerosol upon heating, the aerosol-generating article comprising: an aerosol-generating element comprising a nicotine-containing aerosolgenerating substrate; and a downstream section located downstream of the aerosol generating element, The downstream section comprises a carboxylic acid selected from the group consisting of citric acid, benzoic acid, fumaric acid, lactic acid and combinations thereof.

According to a second aspect of the present invention, there is provided an aerosolgenerating system comprising an electrically operated aerosol-generating device and an aerosol-generating article according to the first aspect of the invention. The aerosolgenerating device comprises means to heat the aerosol-generating substrate to a temperature sufficient to generate an aerosol from the aerosol generating substrate.

As used herein with reference to the invention, the term “aerosol-generating article” is used to describe an article comprising an aerosol-generating substrate that is heated to generate an inhalable aerosol for delivery to a user.

As used herein with reference to the invention, the term “aerosol-generating substrate” is used to describe a substrate comprising aerosol-generating material that is capable of releasing an aerosol upon heating volatile compounds that can generate an aerosol. In particular, the aerosol-generating substrate is a solid aerosol-generating substrate. Solid, nicotine-containing aerosol-generating substrates include both tobacco-containing substrates and non-tobacco substrates. Tobacco-containing substrates comprise tobacco plant material (for example tobacco leaf material cut into shreds, or homogenised tobacco material made from particles of tobacco leaf material as will be described in more detail below). Non-tobacco substrates may include a solid carrier material (for example, plant material from a plant other than tobacco, or a cellulosic material like paper) to which a composition containing nicotine has been applied, as a coating, by impregnation or otherwise. A conventional cigarette is lit when a user applies a flame to one end of the cigarette and draws air through the other end. The localised heat provided by the flame and the oxygen in the air drawn through the cigarette causes the end of the cigarette to ignite, and the resulting combustion generates an inhalable smoke. By contrast, in heated aerosol generating articles, an aerosol is generated by heating a flavour generating substrate, such as tobacco, without combustion of the flavour generating substrate. Known heated aerosol generating articles include, for example, electrically heated aerosol generating articles and aerosol generating articles in which an aerosol is generated by the transfer of heat from a heat source to a physically separate aerosol forming material.

Aerosol-generating articles according to the invention find particular application in aerosol-generating systems comprising an aerosol-generating device having a heating chamber into which the aerosol-generating article is received such that heat can be supplied to the aerosol-generating substrate. This may be achieved by providing one or more heating elements arranged about the periphery of the heating chamber, the one or more heating elements being heated resistively or inductively. Alternatively, this may also be achieved by way of a resistively heated blade-shaped component of the aerosol-generating device, which is inserted into the aerosol-generating substrate when the aerosol-generating article is inserted into the heating chamber.

According to yet another alternative, a susceptor element may be provided within the aerosol-generating substrate, and the aerosol-generating device may have an inductor for producing an alternating or fluctuating electromagnetic field. When the aerosol-generating article engages with the aerosol-generating device, the fluctuating electromagnetic field produced by the inductor induces a current in the susceptor element, causing the susceptor element to heat up. The electrically-operated aerosol-generating device may be capable of generating a fluctuating electromagnetic field having a magnetic field strength (H-field strength) of between 1 and 5 kilo amperes per metre (kA m), preferably between 2 and 3 kA/m, for example about 2.5 kA/m.

Aerosol-generating articles according to the invention have a proximal end through which, in use, an aerosol exits the aerosol-generating article for delivery to a user. The proximal end of the aerosol-generating article may also be referred to as the downstream end or the mouth end of the aerosol-generating article. In use, a user draws directly or indirectly on the proximal end of the aerosol-generating article in order to inhale an aerosol generated by the aerosol-generating article.

Aerosol-generating articles according to the invention have a distal end. The distal end is opposite the proximal end. The distal end of the aerosol-generating article may also be referred to as the upstream end of the aerosol-generating article. Components of aerosol-generating articles according to the invention may be described as being upstream or downstream of one another based on their relative positions between the proximal end of the aerosol-generating article and the distal end of the aerosolgenerating article.

As used herein with reference to the invention, the term “longitudinal” is used to describe the direction between the upstream end and the downstream end of the aerosolgenerating article. During use, air is drawn through the aerosol-generating article in the longitudinal direction.

As used herein with reference to the invention, the term “length” is used to describe the maximum dimension of the aerosol-generating article or a component of the aerosolgenerating article in the longitudinal direction.

As used herein with reference to the invention, the term “transverse” is used to describe the direction perpendicular to the longitudinal direction. Unless otherwise stated, references to the “cross-section” of the aerosol-generating article or a component of the aerosol-generating article refer to the transverse cross-section.

As used herein with reference to the invention, the term “width” denotes the maximum dimension of the aerosol-generating article or a component of the aerosol-generating article in a transverse direction. Where the aerosol-generating article has a substantially circular cross-section, the width of the aerosol-generating article corresponds to the diameter of the aerosol-generating article. Where a component of the aerosol-generating article has a substantially circular cross-section, the width of the component of the aerosol-generating article corresponds to the diameter of the component of the aerosol-generating article.

As used herein with reference to the invention, the term "hollow tubular element" is used to denote a generally cylindrical element having a lumen along a longitudinal axis thereof. The tubular portion may have a substantially circular, oval or elliptical cross-section. The lumen may have a substantially circular, oval or elliptical cross-section. In particular, the term "hollow tubular element" is used to denote an element defining at least one airflow conduit establishing an uninterrupted fluid communication between an upstream end of the hollow tubular element and a downstream end of the tubular element.

The term “carboxylic acid” is used herein to define a class of organic compounds that contain a carboxyl group wherein a carbon atom is bonded to an oxygen atom by a double bond and to a hydroxyl group by a single bond.

As described briefly above, an aerosol-generating article according to an aspect of the present invention comprises an aerosol-generating element comprising an aerosol-generating substrate. In contrast to known aerosol-generating articles, the aerosol-generating article further comprises a downstream section located downstream of the aerosol generating element, wherein the downstream section comprises a carboxylic acid selected from the group consisting of citric acid, benzoic acid, fumaric acid, lactic acid and combinations thereof.

The inventors have found that providing at least one of the carboxylic acids listed above at a location downstream of the aerosol-generating article advantageously attenuates or even substantially prevents the occurrence of the uncomfortable feeling in the throat consumers have been known to associate with harshness of the aerosol, without significantly impacting the overall taste of the aerosol.

Nicotine in the aerosol typically exists in the form of non-protonated nicotine (also referred to as freebase nicotine), which tends to be more volatile than protonated nicotine and hence is delivered to the consumer in amounts which may lead to an increase in perceived throat harshness. Without wishing to be bound by theory, it is understood that the acidity of the hydroxyl proton, which in the carboxylic acids listed above is enhanced by the vicinity of the carbonyl group, makes these acids highly reactive with weak bases, like the volatile, nonprotonated nicotine present in the aerosol.

Providing one or more of the carboxylic acids listed above at a location in the aerosolgenerating article downstream of the aerosol-generating substrate thus has the beneficial effect that the freebase nicotine in the aerosol gets to interact and react with the acidic proton of the carboxylic acid before reaching the downstream end of the article. Thus, the freebase nicotine is at least partially replaced by its less volatile, protonated form prior to the aerosol reaching the consumer’s mouth. The nicotine in protonated form tends to be bound into the particulate phase, rather than in the gaseous phase, of the aerosol being provided to the consumer. As a result, the perceived throat harshness is advantageously reduced.

Citric acid, benzoic acid, fumaric acid, and lactic acid all occur widely in nature, and are generally biodegradable. As such, incorporating one or more of these carboxylic acids in an aerosol-generating article does not substantially add to their overall environmental impact.

The carboxylic acids listed above can easily be incorporated into one or more component of the downstream section of the aerosol-generating article prior to the various components being combined to form the aerosol-generating article. As will be described in more detail below, this requires only minor modifications of existing manufacturing processes. Therefore, aerosol-generating articles according to the invention can advantageously be manufactured efficiently and at high speed without the need for extensive modification of existing equipment.

As described briefly above, in an aerosol-generating article according to the present invention one or more of citric acid, benzoic acid, fumaric acid, and lactic acid are provided at a location in the downstream section. The downstream section of an aerosol-generating article may comprise one or more component, each one of the one or more component arranged in axial alignment with the aerosol-generating element. For example, the downstream section of the aerosol-generating article may comprise a mouthpiece filter element (MPF) at the downstream end of the aerosol-generating article.

In some embodiments, the MPF may be provided immediately downstream of the aerosol-generating element. Preferably, the MPF is provided adjacent to the aerosolgenerating element, a downstream end of the aerosol-generating element abutting an upstream end of the MPF.

In other embodiments, the downstream section may comprise one or more intermediate components provided between the aerosol-generating element and the MPF. For example, as will be described in more detail below, the downstream section may comprise one or more of a support element, an aerosol-cooling element, and so forth.

In a preferred embodiment, the downstream section of the aerosol-generating article comprises a MPF and the carboxylic acid is provided at a location within the MPF.

The MPF may advantageously provide support for the carboxylic acid, such that it is promptly available for interacting with the aerosol volatilised species. For example, the carboxylic acid may be dispersed within the fibrous filtration material forming a plug element of the MPF. Providing the carboxylic acid at a location within the MPF may be especially convenient from a manufacturing viewpoint since, as will be discussed in more detail below, it is easy to adapt existing processes for manufacturing an MPF containing an additive to the incorporation of the carboxylic acid in accordance with the invention.

In another embodiment, the downstream section of the aerosol-generating article comprises a support element, and the carboxylic acid is provided at a location within the support element.

Typically, in an aerosol-generating article the support element is provided immediately downstream of the aerosol-generating element. Preferably, the support element is provided adjacent to the aerosol-generating element, a downstream end of the aerosol-generating element abutting an upstream end of the support element.

Providing the carboxylic acid in a support element, particularly one adjacent to the aerosol-generating element, has the benefit that the aerosol volatilised species may begin to interact with the hydroxyl protons of the carboxylic functional groups immediately after being released from the aerosol-generating substrate. As a result, there is an increased likelihood that a larger fraction of protonated species have the time to accumulate in the particulate phase prior to the aerosol reaching the downstream end of the article.

As described briefly above, in certain embodiments the downstream section of the aerosol-generating article may comprise an aerosol-cooling element. Typically, the aerosolcooling element is located at an intermediate position between the aerosol-generating element and the downstream end of the article, preferably upstream of a MPF. In some cases, the aerosol-cooling element may be provided immediately downstream of the aerosol-generating element, and preferably adjacent to the aerosol-generating element. Thus, a downstream end of the aerosol-generating element abuts an upstream end of the aerosol-cooling element.

In other cases, the aerosol-cooling element may be arranged immediately downstream of a support element which, in turn, is located immediately downstream of the aerosolgenerating element. For example, the support element may be adjacent to the aerosolgenerating element and the aerosol-cooling element may be adjacent to the support element, such three components of the aerosol-generating article being in sequential, abutting arrangement.

In an embodiment, the downstream section of the aerosol-generating article comprises an aerosol cooling element adjacent the aerosol generating element, and the carboxylic acid is provided at a location in the aerosol cooling element.

In a further embodiment, the downstream section comprises a support element downstream of the aerosol-generating element and an aerosol cooling element downstream of the support element, the carboxylic acid being provided at a location in the aerosol cooling element.

Providing the carboxylic acid at a location in the aerosol-cooling element may have specific benefits.

In certain embodiments, aerosol-cooling elements of aerosol-generating article may be generally configured to provide, within a relatively small volume, a fairly large surface area for heat exchange, so that the temperature of the aerosol can be lowered as efficiently and rapidly as possible. For example, aerosol-cooling elements have been described which comprise a gathered sheet of a polymeric material, such as polylactic acid, the gathered sheet defining a plurality of elongate channels extending along a longitudinal axis of the article. Providing the carboxylic acid at a location in one such aerosol-cooling element has the benefit that the carboxylic acid may be for example applied over a fairly large surface that is exposed, during use, to the aerosol flowing through the aerosol-cooling element. As a result, the large surface area of the aerosol-cooling element may also favour the occurrence of effective interactions between aerosol volatilised species and the molecules of carboxylic acid.

In other embodiments, the aerosol-cooling element may be configured to rely on the admission of air from outside the aerosol-generating article into a cavity defined within the aerosol-cooling element to lower the temperature of the aerosol. This may result in a relatively rapid cooling of the aerosol, which may be associated with the quick formation of new nuclei of aerosol particles. Providing the carboxylic acid at a location in one such aerosol-cooling element may have the benefit that the carboxylic acid may be available to react with aerosol volatilised species immediately prior to them condensing to form new nuclei or binding to already formed aerosol particles, and so the harshness-reducing function may be enhanced.

In some embodiments, the aerosol-generating article further comprises an upstream section located upstream of the aerosol generating element. The provision of an upstream section may have a number of benefits, which will be discussed in more detail below. In a preferred one of such embodiments, the upstream section is free of carboxylic acid.

As will be apparent from the foregoing description, the present invention provides a number of different possible arrangements as concerns the exact location of the carboxylic acid within the aerosol-generating article. In general, providing the carboxylic acid at a location closer to or farther away from the downstream end of the aerosol-generating article may have an impact on the amount of interactions between the nicotine in the aerosol and the carboxylic acid. Providing the carboxylic acid at a location farther downstream from the aerosolgenerating element may be advantageous in that the carboxylic acid may get to interact with residual freebase nicotine still remaining in the aerosol as it approaches the mouth end of the article, and so this may maximise the fraction of freebase nicotine that is reacted into its protonated form. This in turn may advantageously minimise the perceived harshness of the aerosol by an adult smoker.

In an aerosol-generating article in accordance with the present invention, the carboxylic acid may be provided in an amount of at least 0.05 milligrams in the downstream section of the aerosol-generating article. Preferably, the carboxylic acid is provided in an amount of at least 0.1 milligrams in the downstream section of the aerosol-generating article. More preferably the carboxylic acid is provided in an amount of at least 0.5 milligrams in the downstream section of the aerosol-generating article.

In preferred embodiments, the carboxylic acid is provided in an amount of at least 1 milligram in the downstream section of the aerosol-generating article. Preferably, the carboxylic acid is provided in an amount of at least 5 milligrams in the downstream section of the aerosol-generating article. More preferably, the carboxylic acid is provided in an amount of at least 15 milligrams in the downstream section of the aerosol-generating article. Even more preferably, the carboxylic acid is provided in an amount of at least 25 milligrams in the downstream section of the aerosol-generating article. Most preferably, the carboxylic acid is provided in an amount of at least 50 milligrams in the downstream section of the aerosolgenerating article.

In preferred embodiments, the carboxylic acid is provided in an amount of at least 75 milligram in the downstream section of the aerosol-generating article. Preferably, the carboxylic acid is provided in an amount of at least 100 milligrams in the downstream section of the aerosol-generating article. In an aerosol-generating article in accordance with the present invention, the carboxylic acid may be provided in an amount of less than or equal to 400 milligrams in the downstream section of the aerosol-generating article. Preferably, the carboxylic acid may be provided in an amount of less than or equal to 350 milligrams in the downstream section of the aerosol-generating article. Preferably, the carboxylic acid is may be provided an amount less than or equal to 250 milligrams in the downstream section of the aerosol-generating article. More preferably, the carboxylic acid is provided is provided in an amount of less than or equal to or equal to 200 milligrams in the downstream section of the aerosol-generating article. Even more preferably, the carboxylic acid is provided in an amount of less than or equal to or equal to 150 milligrams in the downstream section of the aerosol-generating article.

In some embodiments, the carboxylic acid may be provided in an amount of from 0.05 milligrams to 200 milligrams in the downstream section of the aerosol-generating article. Preferably, the carboxylic acid may be provided in an amount of from 0.1 milligrams to 200 milligrams in the downstream section of the aerosol-generating article. Preferably, the carboxylic acid may be provided in an amount of from 0.5 milligrams to 200 milligrams in the downstream section of the aerosol-generating article. More preferably, the carboxylic acid may be provided in an amount of from 1 milligram to 200 milligrams in the downstream section of the aerosol-generating article. More preferably, the carboxylic acid may be provided in an amount of from 5 milligrams to 200 milligrams in the downstream section of the aerosolgenerating article. Even more preferably, the carboxylic acid may be provided in an amount of from 15 milligrams to 200 milligrams in the downstream section of the aerosol-generating article. Even more preferably, the carboxylic acid may be provided in an amount of from 25 milligrams to 200 milligrams in the downstream section of the aerosol-generating article. Most preferably, the carboxylic acid may be provided in an amount of from 50 milligrams to 200 milligrams in the downstream section of the aerosol-generating article.

In some embodiments, the carboxylic acid may be provided in an amount of from 0.05 milligrams to 150 milligrams in the downstream section of the aerosol-generating article. Preferably, the carboxylic acid may be provided in an amount of from 0.1 milligrams to 150 milligrams in the downstream section of the aerosol-generating article. Preferably, the carboxylic acid may be provided in an amount of from 0.5 milligrams to 150 milligrams in the downstream section of the aerosol-generating article. More preferably, the carboxylic acid may be provided in an amount of from 1 milligram to 150 milligrams in the downstream section of the aerosol-generating article. More preferably, the carboxylic acid may be provided in an amount of from 5 milligrams to 150 milligrams in the downstream section of the aerosolgenerating article. Even more preferably, the carboxylic acid may be provided in an amount of from 15 milligrams to 150 milligrams in the downstream section of the aerosol-generating article. Even more preferably, the carboxylic acid may be provided in an amount of from 25 milligrams to 150 milligrams in the downstream section of the aerosol-generating article. Most preferably, the carboxylic acid may be provided in an amount of from 50 milligrams to 150 milligrams in the downstream section of the aerosol-generating article.

In an aerosol-generating article in accordance with the present invention, an overall amount of the carboxylic acid may be at least 2.6 micromoles. Preferably, an overall amount of the carboxylic acid is at least 5 micromoles. More preferably, an overall amount of the carboxylic acid is at least 40 micromoles. Even more preferably, an overall amount of the carboxylic acid is at least 122 micromoles. In more preferred embodiments, an overall amount of the carboxylic acid is at least 215 micromoles. In particularly preferred embodiments, an overall amount of the carboxylic acid is at least 520 micromoles.

In an aerosol-generating article in accordance with the present invention, an overall amount of the carboxylic acid may be less than or equal to 2700 micromoles. Preferably, an overall amount of the carboxylic acid is less than or equal to 1700 micromoles. More preferably, an overall amount of the carboxylic acid is less than or equal to 1220 micromoles. In particularly preferred embodiments, an overall amount of the carboxylic acid is less than or equal to 555 micromoles.

In some embodiments, an overall amount of the carboxylic acid in the downstream section of the aerosol-generating article is from 2.6 micromoles to 2700 micromoles, preferably from 5 micromoles 2700 micromoles, more preferably from 40 micromoles to 2700 micromoles, even more preferably from 122 micromoles to 2700 micromoles, and particularly preferably 215 micromoles to 2700 micromoles or 520 micromoles to 2700 micromoles.

In other embodiments, an overall amount of the carboxylic acid in the downstream section of the aerosol-generating article is from 2.6 micromoles to 1700 micromoles, preferably from 5 micromoles 1700 micromoles, more preferably from 40 micromoles to 1700 micromoles, even more preferably from 122 micromoles to 1700 micromoles, and particularly preferably 215 micromoles to 1700 micromoles or 520 micromoles to 1700 micromoles.

In further embodiments, an overall amount of the carboxylic acid in the downstream section of the aerosol-generating article is from 2.6 micromoles to 1220 micromoles, preferably from 5 micromoles 1220 micromoles, more preferably from 40 micromoles to 1220 micromoles, even more preferably from 122 micromoles to 1220 micromoles, and particularly preferably 215 micromoles to 1220 micromoles or 520 micromoles to 1220 micromoles.

In even further embodiments, an overall amount of the carboxylic acid in the downstream section of the aerosol-generating article is from 2.6 micromoles to 555 micromoles, preferably from 5 micromoles 555 micromoles, more preferably from 40 micromoles to 555 micromoles, even more preferably from 122 micromoles to 555 micromoles, and particularly preferably 215 micromoles to 555 micromoles or 520 micromoles to 555 micromoles. As mentioned above, in certain embodiments, the downstream section comprises a mouthpiece filter (MPF) and the carboxylic acid is provided at a location within the MPF.

In some preferred embodiments, the carboxylic acid is provided in an amount of at least 0.05 milligrams in the MPF. Preferably, the carboxylic acid is provided in an amount of at least 0.1 milligrams in the MPF. More preferably the carboxylic acid is provided in an amount of at least 0.5 milligrams in the MPF.

In preferred embodiments, the carboxylic acid is provided in an amount of at least 1 milligram in the MPF. Preferably, the carboxylic acid is provided in an amount of at least 5 milligrams in the MPF. More preferably, the carboxylic acid is provided in an amount of at least 15 milligrams in the MPF. Even more preferably, the carboxylic acid is provided in an amount of at least 25 milligrams in the MPF. Most preferably, the carboxylic acid is provided in an amount of at least 50 milligrams in the MPF.

In preferred embodiments, the carboxylic acid is provided in an amount of at least 75 milligram in the MPF. Preferably, the carboxylic acid is provided in an amount of at least 100 milligrams in the MPF.

In some embodiments, the carboxylic acid may be provided in an amount less than or equal to 400 milligrams in the MPF. Preferably, the carboxylic acid is provided in an amount less than or equal to 350 milligrams in the MPF. Preferably, the carboxylic acid is provided an amount less than or equal to 250 milligrams in the MPF. More preferably, the carboxylic acid is provided is provided in an amount less than or equal to or equal to 200 milligrams in the MPF. Even more preferably, the carboxylic acid is provided in an amount less than or equal to or equal to 150 milligrams in the MPF.

In some embodiments, the carboxylic acid may be provided in an amount from 0.05 milligrams to 200 milligrams in the MPF, preferably in an amount from 0.1 milligrams to 200 milligrams in the MPF, more preferably in an amount from 0.5 milligrams to 200 milligrams in the MPF, even more preferably in an amount from 1 milligram to 200 milligrams in the MPF. In particularly preferred embodiments, the carboxylic acid may be provided in an amount from 5 milligrams to 200 milligrams in the MPF, preferably in an amount from 15 milligrams to 200 milligrams in the MPF, more preferably in an amount from 25 milligrams to 200 milligrams in the MPF, even more preferably in an amount from 50 milligrams to 200 milligrams in the MPF.

In some embodiments, the carboxylic acid may be provided in an amount from 0.05 milligrams to 150 milligrams in the MPF, preferably in an amount from 0.1 milligrams to 150 milligrams in the MPF, more preferably in an amount from 0.5 milligrams to 150 milligrams in the MPF, even more preferably in an amount from 1 milligram to 150 milligrams in the MPF. In particularly preferred embodiments, the carboxylic acid is provided in an amount from 5 milligrams to 150 milligrams in the MPF, preferably in an amount from 15 milligrams to 150 milligrams in the MPF, more preferably in an amount from 25 milligrams to 150 milligrams in the MPF, even more preferably in an amount from 50 milligrams to 150 milligrams in the MPF.

In some embodiments, an overall amount of the carboxylic acid may be at least 2.6 micromoles in the MPF. Preferably, an overall amount of the carboxylic acid is at least 5 micromoles in the MPF. More preferably, an overall amount of the carboxylic acid is at least 40 micromoles in the MPF. Even more preferably, an overall amount of the carboxylic acid is at least 122 micromoles in the MPF. In preferred embodiments, an overall amount of the carboxylic acid is at least 215 micromoles in the MPF. In particularly preferred embodiments, an overall amount of the carboxylic acid is at least 520 micromoles in the MPF.

In some embodiments, an overall amount of the carboxylic acid may be less than or equal to 2700 micromoles in the MPF. Preferably, an overall amount of the carboxylic acid is less than or equal to 1700 micromoles in the MPF. More preferably, an overall amount of the carboxylic acid is less than or equal to 1220 micromoles in the MPF. In particularly preferred embodiments, an overall amount of the carboxylic acid is less than or equal to 555 micromoles in the MPF.

In some embodiments, an overall amount of the carboxylic acid in the MPF is from 2.6 micromoles to 2700 micromoles, preferably from 5 micromoles 2700 micromoles, more preferably from 40 micromoles to 2700 micromoles, even more preferably from 122 micromoles to 2700 micromoles, and particularly preferably 215 micromoles to 2700 micromoles or 520 micromoles to 2700 micromoles.

In other embodiments, an overall amount of the carboxylic acid in the MPF is from 2.6 micromoles to 1700 micromoles, preferably from 5 micromoles 1700 micromoles, more preferably from 40 micromoles to 1700 micromoles, even more preferably from 122 micromoles to 1700 micromoles, and particularly preferably 215 micromoles to 1700 micromoles or 520 micromoles to 1700 micromoles.

In further embodiments, an overall amount of the carboxylic acid in the MPF is from 2.6 micromoles to 1220 micromoles, preferably from 5 micromoles 1220 micromoles, more preferably from 40 micromoles to 1220 micromoles, even more preferably from 122 micromoles to 1220 micromoles, and particularly preferably 215 micromoles to 1220 micromoles or 520 micromoles to 1220 micromoles.

In even further embodiments, an overall amount of the carboxylic acid in the MPF is from 2.6 micromoles to 555 micromoles, preferably from 5 micromoles 555 micromoles, more preferably from 40 micromoles to 555 micromoles, even more preferably from 122 micromoles to 555 micromoles, and particularly preferably 215 micromoles to 555 micromoles or 520 micromoles to 555 micromoles.

In some embodiments, there is an overall amount of at least 0.5 micromoles of carboxylic acid per millimetre of MPF. Preferably, there is an overall amount of at least 1 micromole of carboxylic acid per millimetre of M PF. More preferably, there is an overall amount of at least 6 micromoles of carboxylic acid per millimetre of MPF. Even more preferably, there is an overall amount of at least 18 micromoles of carboxylic acid per millimetre of MPF. In preferred embodiments, there is an overall amount of at least 31 micromoles of carboxylic acid per millimetre of MPF. In particularly preferred embodiments, there is an overall amount of at least 80 micromoles of carboxylic acid per millimetre of MPF.

In some embodiments, there is an overall amount of less than or equal to or equal to 390 micromoles of carboxylic acid per millimetre of MPF. Preferably, there is an overall amount of less than or equal to or equal to 250 micromoles of carboxylic acid per millimetre of MPF. More preferably, there is an overall amount of less than or equal to or equal to 185 micromoles of carboxylic acid per millimetre of MPF. In preferred embodiments, there is an overall amount of less than or equal to or equal to 120 micromoles of carboxylic acid per millimetre of MPF.

In some embodiments there is an overall amount of 0.5 micromoles to 390 micromoles of carboxylic acid per millimetre of MPF, preferably from 1 micromole to 390 micromoles of carboxylic acid per millimetre of MPF, more preferably from 6 micromoles to 390 micromoles of carboxylic acid per millimetre of MPF, even more preferably from 31 micromoles to 390 of carboxylic acid micromoles per millimetre of MPF, and particularly preferably from 80 micromoles to 390 micromoles of carboxylic acid per millimetre of MPF.

In some embodiments there is an overall amount of 0.5 micromoles to 250 micromoles of carboxylic acid per millimetre of MPF, preferably from 1 micromole to 250 micromoles of carboxylic acid per millimetre of MPF, more preferably from 6 micromoles to 250 micromoles of carboxylic acid per millimetre of MPF, even more preferably from 31 micromoles to 250 of carboxylic acid micromoles per millimetre of MPF, and particularly preferably from 80 micromoles to 250 micromoles of carboxylic acid per millimetre of MPF.

In some embodiments there is an overall amount of 0.5 micromoles to 185 micromoles of carboxylic acid per millimetre of MPF, preferably from 1 micromole to 185 micromoles of carboxylic acid per millimetre of MPF, more preferably from 6 micromoles to 185 micromoles of carboxylic acid per millimetre of MPF, even more preferably from 31 micromoles to 185 of carboxylic acid micromoles per millimetre of MPF, and particularly preferably from 80 micromoles to 185 micromoles of carboxylic acid per millimetre of MPF.

In some embodiments there is an overall amount of 0.5 micromoles to 120 micromoles of carboxylic acid per millimetre of MPF, preferably from 1 micromole to 120 micromoles of carboxylic acid per millimetre of MPF, more preferably from 6 micromoles to 120 micromoles of carboxylic acid per millimetre of MPF, even more preferably from 31 micromoles to 120 of carboxylic acid micromoles per millimetre of MPF, and particularly preferably from 80 micromoles to 120 micromoles of carboxylic acid per millimetre of MPF.

In particularly preferred embodiments, the carboxylic acid is citric acid. In some embodiments, citric acid is provided in an amount of at least 0.05 milligrams in the downstream section of the aerosol-generating article. Preferably, citric acid is provided in an amount of at least 0.1 milligrams in the downstream section of the aerosol-generating article. More preferably citric acid is provided in an amount of at least 0.5 milligrams in the downstream section of the aerosol-generating article.

In preferred embodiments, citric acid is provided in an amount of at least 1 milligram in the downstream section of the aerosol-generating article. Preferably, citric acid is provided in an amount of at least 5 milligrams in the downstream section of the aerosol-generating article. More preferably, citric acid is provided in an amount of at least 15 milligrams in the downstream section of the aerosol-generating article. Even more preferably, citric acid is provided in an amount of at least 25 milligrams in the downstream section of the aerosolgenerating article. In particularly preferred embodiments, citric acid is provided in an amount of at least 50 milligrams in the downstream section of the aerosol-generating article.

In certain embodiments, citric acid is provided in an amount of at least 75 milligram in the downstream section of the aerosol-generating article. Preferably, citric acid is provided in an amount of at least 100 milligrams in the downstream section of the aerosol-generating article.

In an aerosol-generating article in accordance with the present invention, citric acid may be provided in an amount of less than or equal to 400 milligrams in the downstream section of the aerosol-generating article. Preferably, citric acid may be provided in an amount less than or equal to 350 milligrams in the downstream section of the aerosol-generating article. Preferably, citric acid is may be provided an amount less than or equal to 250 milligrams in the downstream section of the aerosol-generating article. More preferably, citric acid is provided is provided in an amount less than or equal to or equal to 200 milligrams in the downstream section of the aerosol-generating article. Even more preferably, citric acid is provided in an amount less than or equal to or equal to 150 milligrams in the downstream section of the aerosol-generating article.

In some embodiments, citric acid is provided in an amount from 0.05 milligrams to 200 milligrams in the downstream section of the aerosol-generating article. Preferably, citric acid is provided in an amount from 0.1 milligrams to 200 milligrams in the downstream section of the aerosol-generating article. More preferably, citric acid is provided in an amount from 0.5 milligrams to 200 milligrams in the downstream section of the aerosol-generating article. Even more preferably, citric acid is provided in an amount from 1 milligram to 200 milligrams in the downstream section of the aerosol-generating article. In particularly preferred embodiments, citric acid is provided in an amount from 5 milligrams to 200 milligrams in the downstream section of the aerosol-generating article. Preferably, citric acid is provided in an amount from 15 milligrams to 200 milligrams in the downstream section of the aerosol-generating article. More preferably, citric acid is provided in an amount from 25 milligrams to 200 milligrams in the downstream section of the aerosol-generating article. Even more preferably, citric acid is provided in an amount from 50 milligrams to 200 milligrams in the downstream section of the aerosol-generating article.

In some embodiments, citric acid is provided in an amount from 0.05 milligrams to 150 milligrams in the downstream section of the aerosol-generating article. Preferably, citric acid is provided in an amount from 0.1 milligrams to 150 milligrams in the downstream section of the aerosol-generating article. More preferably, citric acid is provided in an amount from 0.5 milligrams to 150 milligrams in the downstream section of the aerosol-generating article. Even more preferably, citric acid is provided in an amount from 1 milligram to 150 milligrams in the downstream section of the aerosol-generating article. In particularly preferred embodiments, citric acid is provided in an amount from 5 milligrams to 150 milligrams in the downstream section of the aerosol-generating article. Preferably, citric acid is provided in an amount from 15 milligrams to 150 milligrams in the downstream section of the aerosol-generating article. More preferably, citric acid is provided in an amount from 25 milligrams to 150 milligrams in the downstream section of the aerosol-generating article. Even more preferably, citric acid is provided in an amount from 50 milligrams to 150 milligrams in the downstream section of the aerosol-generating article.

In certain embodiments, an overall amount of citric acid is at least 3 micromoles in the downstream section. Preferably, an overall amount of citric acid is at least 5 micromoles in the downstream section. More preferably, an overall amount of citric acid is at least 25 micromoles in the downstream section. Even more preferably, an overall amount of citric acid is at least 80 micromoles in the downstream section. In more preferred embodiments, an overall amount of citric acid is at least 140 micromoles in the downstream section. In particularly preferred embodiments, an overall amount of citric acid is at least 260 micromoles in the downstream section.

In some embodiments, an overall amount of citric acid is less than or equal to 1300 micromoles in the downstream section. Preferably, an overall amount of citric acid is less than or equal to 1040 micromoles in the downstream section. More preferably, an overall amount of citric acid is less than or equal to 780 micromoles in the downstream section. In particularly preferred embodiments, an overall amount of citric acid is less than or equal to 520 micromoles in the downstream section.

In some embodiments, an overall amount of the citric acid in the downstream section of the aerosol-generating article is from 3 micromoles to 1300 micromoles, preferably from 5 micromoles to 1300 micromoles, more preferably from 25 micromoles to 1300 micromoles, even more preferably from 80 micromoles to 1300 micromoles, and particularly preferably 140 micromoles to 1300 micromoles or 260 micromoles to 1300 micromoles or 520 micromoles to 1300 micromoles.

In other embodiments, an overall amount of the citric acid in the downstream section of the aerosol-generating article is from 3 micromoles to 1040 micromoles, preferably from 5 micromoles 1040 micromoles, more preferably from 25 micromoles to 1040 micromoles, even more preferably from 80 micromoles to 1040 micromoles, and particularly preferably 130 micromoles to 1040 micromoles or 260 micromoles to 1040 micromoles or 520 micromoles to 1040 micromoles.

In further embodiments, an overall amount of the citric acid in the downstream section of the aerosol-generating article is from 3 micromoles to 780 micromoles, preferably from 5 micromoles 780 micromoles, more preferably from 25 micromoles to 780 micromoles, even more preferably from 80 micromoles to 780 micromoles, and particularly preferably 130 micromoles to 780 micromoles or 260 micromoles to 780 micromoles or 520 micromoles to 780 micromoles.

In certain embodiments, citric acid is provided in an amount of at least 0.05 milligrams in the MPF. Preferably, citric acid is provided in an amount of at least 0.1 milligrams in the MPF. More preferably citric acid is provided in an amount of at least 0.5 milligrams in the MPF.

In preferred embodiments, citric acid is provided in an amount of at least 1 milligram in the MPF. Preferably, citric acid is provided in an amount of at least 5 milligrams in the MPF. More preferably, citric acid is provided in an amount of at least 15 milligrams in the MPF. Even more preferably, citric acid is provided in an amount of at least 25 milligrams in the MPF. In particularly preferred embodiments, citric acid is provided in an amount of at least 50 milligrams in the MPF.

In some embodiments, citric acid is provided in an amount of at least 75 milligram in the MPF. Preferably, citric acid is provided in an amount of at least 100 milligrams in the MPF.

In certain embodiments, citric acid is provided in an amount less than or equal to 400 milligrams in the MPF. Preferably, citric acid is provided in an amount less than or equal to 350 milligrams in the MPF. More preferably, citric acid is provided an amount less than or equal to 250 milligrams in the MPF. Even more preferably, citric acid is provided is provided in an amount less than or equal to or equal to 200 milligrams in the MPF. In particularly preferred embodiments, citric acid is provided in an amount less than or equal to or equal to 150 milligrams in the MPF.

In some embodiments, citric acid is provided in an amount from 0.05 milligrams to 200 milligrams in the MPF. Preferably, citric acid is provided in an amount from 0.1 milligrams to 200 milligrams in the MPF. More preferably, citric acid is provided in an amount from 0.5 milligrams to 200 milligrams in the MPF. Even more preferably, citric acid is provided in an amount from 1 milligram to 200 milligrams in the MPF. In particularly preferred embodiments, citric acid is provided in an amount from 5 milligrams to 200 milligrams in the MPF. Preferably, citric acid is provided in an amount from 15 milligrams to 200 milligrams in the MPF. More preferably, citric acid is provided in an amount from 25 milligrams to 200 milligrams in the MPF. Even more preferably, citric acid is provided in an amount from 50 milligrams to 200 milligrams in the MPF.

In some embodiments, citric acid is provided in an amount from 0.05 milligrams to 150 milligrams in the MPF. Preferably, citric acid is provided in an amount from 0.1 milligrams to 150 milligrams in the MPF. More preferably, citric acid is provided in an amount from 0.5 milligrams to 150 milligrams in the MPF. Even more preferably, citric acid is provided in an amount from 1 milligram to 150 milligrams in the MPF. In particularly preferred embodiments, citric acid is provided in an amount from 5 milligrams to 150 milligrams in the MPF. Preferably, citric acid is provided in an amount from 15 milligrams to 150 milligrams in the MPF. More preferably, citric acid is provided in an amount from 25 milligrams to 150 milligrams in the MPF. Even more preferably, citric acid is provided in an amount from 50 milligrams to 150 milligrams in the MPF.

In some embodiments, there is an overall amount of at least 0.4 micromoles of citric acid per millimetre of MPF. Preferably, there is an overall amount of at least 1 micromole of citric acid per millimetre of MPF. More preferably, there is an overall amount of at least 5 micromoles of citric acid per millimetre of MPF. Even more preferably, there is an overall amount of at least 11 micromoles of citric acid per millimetre of MPF. In more preferred embodiments, there is an overall amount of at least 20 micromoles of citric acid per millimetre of MPF. In particularly preferred embodiments, there is an overall amount of at least 40 micromoles of citric acid per millimetre of MPF.

In certain embodiments, there is an overall amount of less than or equal to 185 micromoles of citric acid per millimetre of MPF. Preferably, there is an overall amount of less than or equal to 150 micromoles of citric acid per millimetre of MPF. More preferably, there is an overall amount of less than or equal to 111 micromoles of citric acid per millimetre of MPF. In particularly preferred embodiments, there is an overall amount of less than or equal to 75 micromoles of citric acid per millimetre of MPF.

In some embodiments there is an overall amount of 0.4 micromoles to 185 micromoles of citric acid per millimetre of MPF, preferably from 1 micromole to 185 micromoles of citric acid per millimetre of MPF, more preferably from 5 micromoles to 185 micromoles of citric acid per millimetre of MPF, even more preferably from 11 micromoles to 185 of citric acid micromoles per millimetre of MPF, and particularly preferably from 20 micromoles to 185 micromoles of citric acid per millimetre of MPF or from 40 micromoles to 185 micromoles of citric acid per millimetre of MPF. In some embodiments there is an overall amount of 0.4 micromoles to 150 micromoles of citric acid per millimetre of MPF, preferably from 1 micromole to 150 micromoles of citric acid per millimetre of MPF, more preferably from 5 micromoles to 150 micromoles of citric acid per millimetre of MPF, even more preferably from 11 micromoles to 150 micromoles of citric acid per millimetre of MPF, and particularly preferably from 20 micromoles to 150 micromoles of citric acid per millimetre of MPF or from 40 micromoles to 150 micromoles of citric acid per millimetre of MPF.

In some embodiments there is an overall amount of 0.4 micromoles to 111 micromoles of citric acid per millimetre of MPF, preferably from 1 micromole to 111 micromoles of citric acid per millimetre of MPF, more preferably from 5 micromoles to 111 micromoles of citric acid per millimetre of MPF, even more preferably from 11 micromoles to 111 micromoles of citric acid per millimetre of MPF, and particularly preferably from 20 micromoles to 111 micromoles of citric acid per millimetre of MPF or from 40 micromoles to 111 micromoles of citric acid per millimetre of MPF.

In some embodiments there is an overall amount of 0.4 micromoles to 75 micromoles of citric acid per millimetre of MPF, preferably from 1 micromole to 75 micromoles of citric acid per millimetre of MPF, more preferably from 5 micromoles to 75 micromoles of citric acid per millimetre of MPF, even more preferably from 11 micromoles to 75 micromoles of citric acid per millimetre of MPF, and particularly preferably from 20 micromoles to 75 micromoles of citric acid per millimetre of MPF or from 40 micromoles to 75 micromoles of citric acid per millimetre of MPF.

As discussed briefly above, the downstream section may comprise one or more components provided in axial alignment with the aerosol-generating substrate. For example, the downstream section may comprise one or more of a support element, an aerosol-cooling element, a mouthpiece element.

In an embodiment, the downstream section is formed of a support element, an aerosolcooling element, and a mouthpiece element arranged sequentially and in abutting relationship with each other. In another embodiments, the downstream section is formed of an aerosolcooling element and a mouthpiece element arranged sequentially and in abutting relationship with each other.

A support element may be provided immediately downstream of the aerosolgenerating substrate, preferably adjacent to the aerosol-generating substrate. One such support element is adapted to impart structural strength to the aerosol-generating article. The support element is advantageously configured to resist downstream movement of the aerosolgenerating substrate during insertion of the heating element of the aerosol-generating device into the aerosol-generating. An aerosol-cooling element may be provided to facilitate cooling of the aerosol generated during use of the aerosol-generating article prior to reaching the downstream end of the aerosol-generating article.

The aerosol-cooling element preferably has a low resistance to draw. That is, the aerosol-cooling element preferably offers a low resistance to the passage of air through the aerosol-generating article. Preferably, the aerosol-cooling element does not substantially affect the resistance to draw of the aerosol-generating article.

The aerosol-cooling element may comprise a plurality of longitudinally extending channels. The plurality of longitudinally extending channels may be defined by a sheet of paper material that has been one or more of crimped, pleated, gathered and folded to form the channels. The plurality of longitudinally extending channels may be defined by a single sheet that has been one or more of crimped, pleated, gathered and folded to form multiple channels. Alternatively, the plurality of longitudinally extending channels may be defined by multiple sheets that have been one or more of crimped, pleated, gathered and folded to form multiple channels.

For example, the aerosol-cooling element may be formed from a gathered sheet of a material having a specific surface area of between approximately 10 square millimetres per milligram and approximately 100 square millimetres per milligram. In some embodiments, the aerosol-cooling element may be formed from a gathered sheet of paper material having a specific surface area of approximately 35 square mm per milligram. For example, the aerosolcooling element may be formed from a gathered sheet of polylactic acid (PLA).

At least one of the support element and the aerosol-cooling element may be in the form of a hollow tubular element. In some embodiments, both the support element and the aerosol-cooling element are in the form of hollow tubular elements, which may differ in length, internal diameter or both.

In an aerosol-generating article in accordance with the present invention, such a hollow tubular element provides an unrestricted flow channel. This means that the hollow tubular element provides a negligible level of RTD. As used herein with reference to the invention, the term “negligible level of RTD” is used to describe an RTD of less than 1 mm H2O per 10 millimetres of length of the hollow tubular substrate element, less than 0.4 mm H2O per 10 millimetres of length of the hollow tubular substrate element, or less than 0.1 mm H2O per 10 millimetres of length of the hollow tubular substrate element. The flow channel should therefore be free from any components that would obstruct the flow of air in a longitudinal direction. Preferably, the flow channel is substantially empty.

The hollow tubular element may have a total length of at least about 10 millimetres, at least about 12 millimetres, or at least about 15 millimetres. The hollow tubular element may have a total length of less than or equal to about 30 millimetres, less than or equal to about 25 millimetres, or less than or equal to about 23 millimetres.

The hollow tubular element may have a total length of between about 10 millimetres and about 30 millimetres, between about 10 millimetres and about 25 millimetres, or between about 10 millimetres and about 23 millimetres. The hollow tubular element may have a total length of between about 12 millimetres and about 30 millimetres, between about 12 millimetres and about 25 millimetres, or between about 12 millimetres and about 23 millimetres. The hollow tubular element may have a total length of between about 12 millimetres and about 30 millimetres, between about 12 millimetres and about 25 millimetres, or between about 12 millimetres and about 23 millimetres.

The total length of the hollow tubular element may be selected based on a desired total length of the aerosol-generating article.

In some embodiments, a ventilation zone may be provided at a location downstream of the aerosol-generating substrate.

By way of example, cooling of a stream of smoke generated upon combusting the aerosol-generating substrate may be achieved by providing a ventilation zone at a location along a mouthpiece of the aerosol-generating article.

As another example, a satisfactory cooling of the stream of aerosol generated upon heating the aerosol-generating substrate and drawn through a hollow tubular element as described above may be achieved by providing a ventilation zone at a location along the hollow tubular element itself. Without wishing to be bound by theory, the temperature drop caused by the admission of cooler, external air into the aerosol-generating article downstream of the aerosol-generating element via the ventilation zone may have an advantageous effect on the nucleation and growth of aerosol particles.

The ventilation zone may comprise a plurality of perforations, for example provided through a tubular wall of the hollow tubular element. The ventilation zone may comprise at least one circumferential row of perforations. The ventilation zone may comprise two circumferential rows of perforations. For example, the perforations may be formed online during manufacturing of the aerosol-generating article. Each circumferential row of perforations may comprise from 8 to 30 perforations.

In some embodiments, the downstream section of the aerosol-generating article may comprise, in sequential order, a support element, an aerosol-cooling element, and a mouthpiece. Preferably, one or more of the support element, aerosol-cooling element, and mouthpiece are in the form of a plug element as described above. As mentioned above, the downstream section of the aerosol-generating article may comprise a mouthpiece element located downstream of the aerosol-generating substrate and at the downstream end or mouth end or proximal end of the aerosol-generating article.

The mouthpiece element may be a mouthpiece filter element wherein the carboxylic acid is provided within the mouthpiece filter. The mouthpiece element may comprise at least one filter segment wherein the carboxylic acid is provided within the filter segment. For example, the mouthpiece element may comprise one or more segments of a fibrous filtration material. Suitable fibrous filtration materials are known in the art. For example, the at least one mouthpiece filter segment may comprise a cellulose acetate filter segment formed of cellulose acetate tow.

Aerosol-generating articles in accordance with the present invention can be manufactured using existing equipment and implementing processes modified essentially only insofar as this is required to incorporate the carboxylic acid at a location in the downstream section. In general, processes for incorporating a carboxylic acid into a component of the downstream section will be known to the skilled person. One such component may then be combined with the remaining components to form the aerosol-generating article according to processes that are customary in the art.

For example, known processes for manufacturing a mouthpiece filter segment from a fibrous filtration material can easily be adapted to incorporate a carboxylic acid into a mouthpiece filter. This applies to a most ordinarily used fibrous material, such as cellulose acetate, as well as to alternative fibrous materials such as wood pulp fibres, natural fibres (e.g. cotton, flax), regenerated cellulose (e.g. rayon), and other synthetic fibres (e.g. acrylic fibres, polyester fibres).

In more detail, the fibrous material, typically provided in bale form, can be drawn into a bundle or “tow” of ten to thirty thousand filaments. The tow is then spread and fluffed up, or “boomed”, usually by being placed under tension and passed over air jets. The bloomed tow is passed through a funnel or other constricting device, and then through a shaped aperture to form the filter rod. The filter rod is provided with an outer layer to maintain its shape, either by being wrapped with a plug wrapping of paper or other sheet material, or by being heated to fuse the outermost filaments into a self-supporting layer.

Plasticizers or binders may be added to the tow during or after blooming with a view to improving the firmness of the filter rods produced in accordance with the procedure described above. These additives cause the filaments to bond to each other at their cross-over points when the tow is gathered, giving the rod an increased firmness. A filter segment so treated must be cured either by heating for a short time or by air curing. As has been done in the past with other additives, such as flavourants and humectants, a carboxylic acid can be incorporated into the filter segment by applying the carboxylic acid to the tow by spraying it in liquid, mist, or aerosol form onto the tow during or after blooming.

Additives can then be applied to the mouthpiece filter segment, such as, in the present invention, a carboxylic acid. Further additives such as flavourings (which form an aerosol when contacted by the hot tobacco smoke and flow with the smoke into the smoker’s mouth) or humectants can also be added. It is known to apply these additives to the tow by spraying them in liquid, mist, or aerosol form onto the tow during or after blooming.

The mouthpiece filter may consist of a single filter segment. The mouthpiece filter may include two or more filter segments axially aligned in an abutting end to end relationship with each other.

Parameters or characteristics described herein in relation to the mouthpiece filter as a whole may equally be applied to a filter segment of the mouthpiece filter.

The mouthpiece filter may have a low particulate filtration efficiency.

The mouthpiece filter may have an RTD of less than or equal to about 25 millimetres H2O, less than or equal to about 20 millimetres H2O, or less than or equal to about 15 millimetres H2O.

The mouthpiece filter may have an RTD of at least about 10 millimetres H2O.

The mouthpiece filter may have an RTD of between about 10 millimetres H2O and to about 25 millimetres H2O, between about 10 millimetres H2O and to about 20 millimetres H2O, or of between about 10 millimetres H2O and to about 15 millimetres H2O.

Providing the carboxylic acid within the mouthpiece filter of the mouthpiece filter has substantially no effect on the overall RTD of the mouthpiece filter.

Preferably, the mouthpiece filter has a substantially circular cross-section.

Preferably, the mouthpiece filter has an external diameter that is substantially the same as the external diameter of the aerosol-generating article.

The mouthpiece filter may have a length of at least about 5 millimetres.

The length of the mouthpiece filter may be less than or equal to about 14 millimetres, preferably less than or equal to 12 millimetres, less than or equal to 10 millimetres or less than or equal to about 9 millimetres.

The length of the mouthpiece filter may be between about 5 millimetres and about 12 millimetres, or between about 5 millimetres and about 9 millimetres.

The length of the mouthpiece filter may be between about 5 millimetres and about 11 millimetres, or between about 5 millimetres and about 9 millimetres.

For example, the length of the mouthpiece filter may preferably be about 7 millimetres.

The length of the mouthpiece filter may be selected based on a desired total length of the aerosol-generating article. The mouthpiece filter may be circumscribed by a plug wrap.

The mouthpiece filter may be unventilated such that air does not enter the aerosolgenerating article along the mouthpiece filter.

The mouthpiece filter may be connected to one or more adjacent components of the aerosol-generating article by means of a tipping wrapper.

The aerosol-generating article may define a mouth end cavity at the downstream end of the aerosol-generating article. For example, the mouthpiece filter may itself be in the form of a hollow tubular element. As an alternative, the mouthpiece filter may include a non-hollow segment immediately upstream of a hollow tubular segment provided at the downstream end of the mouthpiece filter. As a further alternative, the mouth end cavity may be defined by an outer wrapper of the mouthpiece filter extending beyond a downstream end of a segment of filtration material of the mouthpiece filter.

In some embodiments, the aerosol-generating article comprises an upstream section located upstream of the aerosol-generating substrate. The upstream section is preferably located immediately upstream of the aerosol-generating substrate. The upstream section preferably extends from an upstream end of the aerosol-generating article to an upstream end of the aerosol-generating substrate. The upstream section preferably comprises an upstream element located immediately upstream of the rod of aerosol-generating substrate.

Where the aerosol-generating substrate comprises shredded tobacco, such as tobacco cut filler, the upstream section or element thereof may additionally help to prevent the loss of loose particles of tobacco from the upstream end of the article.

The upstream section, or upstream element thereof, may also additionally provide a degree of protection to the aerosol-generating substrate during storage, as it covers at least to some extent the upstream end of the aerosol-generating substrate, which may otherwise be exposed. For aerosol-generating articles that are intended to be inserted into a cavity in an aerosol-generating device such that the aerosol-generating substrate can be externally heated within the cavity, the upstream section, or upstream element thereof, may advantageously facilitate the insertion of the upstream end of the article into the cavity.

An upstream element of the upstream section may be made of any material suitable for use in an aerosol-generating article. The upstream element may, for example, be made of a same material as used for one of the other components of the aerosol-generating article, such as the mouthpiece, the aerosol-cooling element or the support element, the geometry and function of which have been described above. Suitable materials for forming the upstream element include filter materials, ceramic, polymer material, cellulose acetate, cardboard, zeolite or aerosol-generating substrate.

Preferably, the upstream section, or an upstream element thereof, has an external diameter that is approximately equal to the external diameter of the aerosol-generating article. Preferably, the external diameter of the upstream section, or an upstream element thereof, is between about 6 millimetres and about 8 millimetres, more preferably between about 7 millimetres and about 7.5 millimetres. Preferably, the upstream section or an upstream element has an external diameter that is about 7.1 mm.

Preferably, the upstream section or an upstream element has a length of between about 2 millimetres and about 8 millimetres, more preferably between about 3 millimetres and about 7 millimetres, more preferably between about 4 millimetres and about 6 millimetres. In a particularly preferred embodiment, the upstream section or an upstream element has a length of about 5 millimetres. The length of the upstream section or an upstream element can advantageously be varied in order to provide the desired total length of the aerosol-generating article.

The upstream section is preferably circumscribed by a wrapper, such as a plug wrap. The wrapper circumscribing the upstream section may be a stiff plug wrap, for example, a plug wrap having a basis weight of at least about 80 grams per square metre (gsm), or at least about 100 gsm, or at least about 110 gsm. This provides increased structural rigidity to the upstream section.

The upstream section is preferably connected to the rod of aerosol-generating substrate and optionally at least a part of the downstream section by means of an outer wrapper.

In preferred embodiments according to the present invention, the upstream section of the aerosol-generating article is free from carboxylic acid.

The aerosol-generating article preferably has an overall length of from 40 millimetres to 80 millimetres, or from 40 millimetres to about 70 millimetres, or from 40 millimetres to about 60 millimetres, or from 45 millimetres to about 80 millimetres, or from about 45 millimetres to about 70 millimetres, or from 45 millimetres to 60 millimetres, or from 50 millimetres to 80 millimetres, or from 50 millimetres to about 70 millimetres or from about 50 millimetres to about 60 millimetres. In an exemplary embodiment, an overall length of the aerosol-generating article is about 45 millimetres.

Preferably, the aerosol-generating article has a substantially circular cross-section.

The aerosol-generating article preferably has an external diameter of from about 5 millimetres to about 12 millimetres, or from about 6 millimetres to about 12 millimetres, or from about 7 millimetres to about 12 millimetres, or from about 5 millimetres to about 10 millimetres, or from about 6 millimetres to about 10 millimetres, or from about 7 millimetres to about 10 millimetres, or from about 5 millimetres to about 8 millimetres, or from about 6 millimetres to about 8 millimetres, or from about 7 millimetres to about 8 millimetres. In other embodiments, the aerosol-generating article has an external diameter of less than 7 millimetres. The overall RTD of the aerosol-generating article is preferably at least 10 millimetres H2O, more preferably at least 15 millimetres H2O, more preferably at least 20 millimetres H2O, more preferably at least 25 millimetres H2O, more preferably at least 30 millimetres H2O.

The overall RTD of the aerosol-generating article is preferably no more than 70 millimetres H2O, more preferably no more than 60 millimetres H2O, more preferably no more than 55 millimetres H2O, more preferably no more than 50 millimetres H2O, more preferably no more than 45 millimetres H2O.

For example, the overall RTD of the aerosol-generating article may be between 10 millimetres H2O and 70 millimetres H2O, or between 15 millimetres H2O and 60 millimetres H2O, or between 20 millimetres H2O and 55 millimetres H2O, or between 25 millimetres H2O and 45 millimetres H2O, or between 30 millimetres H2O and 45 millimetres H2O.

As described above, an aerosol-generating article in accordance with the present invention comprises an aerosol-generating substrate. In several embodiments, the aerosolgenerating article comprises a rod of aerosol-generating substrate circumscribed by a rod plug wrap.

Preferably, the rod of aerosol-generating substrate has a length of at least 8 millimetres, more preferably a length of at least 9 millimetres, more preferably a length of at least 10 millimetres. Preferably, the length of the rod of aerosol-generating substrate is less than 16 millimetres, more preferably less than 15 millimetres, more preferably less than 14 millimetres. For example, the rod of aerosol-generating substrate may have a length of between 8 millimetres and 16 millimetres, or between 9 millimetres and 15 millimetres, or between 10 millimetres and 14 millimetres. In a particularly preferred embodiment, the rod of aerosol-generating substrate has a length of about 12 millimetres.

Preferably, the ratio between the length of the rod of aerosol-generating substrate and the overall length of the aerosol-generating article is at least 0.10, more preferably at least 0.15, more preferably at least 0.20, more preferably at least 0.25. Preferably, the ratio between the length of the rod of aerosol-generating substrate and the overall length of the aerosolgenerating article is less than 0.50, more preferably less than 0.45, more preferably less than 0.40, more preferably less than 0.35. For example, the ratio between the length of the rod of aerosol-generating substrate and the overall length of the aerosol-generating article may be between 0.1 and 0.5, or between 0.15 and 0.45, or between 0.2 and 0.4, or between 0.25 and 0.35.

Preferably, the rod of aerosol-generating substrate has an external diameter that is approximately equal to the external diameter of the aerosol-generating article.

Preferably, the rod of aerosol-generating substrate has an external diameter of at least 5 millimetres, more preferably at least 6 millimetres, more preferably at least 7 millimetres. Preferably, the rod of aerosol-generating substrate has an external diameter of less than 12 millimetres, more preferably less than 10 millimetres, more preferably less than 8 millimetres. For example, the external diameter may be between 5 millimetres and 12 millimetres, or between 6 millimetres and 10 millimetres, or between 7 millimetres and 8 millimetres. In a particularly preferred embodiment, the rod of aerosol-generating substrate has an external diameter of about 7.1 millimetres.

Preferably, the rod of aerosol-generating substrate has a substantially uniform crosssection along the length of the rod. Particularly preferably, the rod of aerosol-generating substrate has a substantially circular cross-section.

The aerosol-generating substrate may have a density of at least about 150 milligrams per cubic centimetre, at least about 175 milligrams per cubic centimetre, at least about 200 milligrams per cubic centimetre, or at least about 250 milligrams per cubic centimetre.

The aerosol-generating substrate may have a density of less than or equal to about 500 milligrams per cubic centimetre, less than or equal to about 450 milligrams per cubic centimetre, less than or equal to about 400 milligrams per cubic centimetre, or less than or equal to about 350 milligrams per cubic centimetre.

The RTD of the rod of aerosol-generating substrate may be at least about 4 millimetres H2O, at least about 5 millimetres H2O, or at least about 6 millimetres H2O.

The RTD of the rod of aerosol-generating substrate may be less than or equal to about 10 millimetres H2O, less than or equal to about 9 millimetres H2O, or less than or equal to about 8 millimetres H2O.

The aerosol-generating substrate may be a solid aerosol-generating substrate. Suitable types of materials for use in the aerosol-generating substrate are described below and include, for example, tobacco cut filler, homogenised tobacco material such as cast leaf, aerosol-generating films and gel compositions.

The aerosol-generating substrate preferably comprises an aerosol former. Suitable aerosol formers are for example: polyhydric alcohols such as, for example, triethylene glycol, 1 ,3-butanediol, propylene glycol and glycerine; esters of polyhydric alcohols such as, for example, glycerol mono-, di- or triacetate; aliphatic esters of mono-, di- or polycarboxylic acids such as, for example, dimethyl dodecanedioate and dimethyl tetradecanedioate; and combinations thereof.

Preferably, the aerosol former comprises one or more of glycerine and propylene glycol. The aerosol former may consist of glycerine or propylene glycol or of a combination of glycerine and propylene glycol.

In certain embodiments, the aerosol-generating substrate preferably comprises at least 5 percent by weight of aerosol former on a dry weight basis of the aerosol-generating substrate, more preferably at least 10 percent by weight on a dry weight basis, more preferably at least 15 percent by weight on a dry weight basis. In such embodiments, the aerosol- generating substrate preferably comprises no more than 30 percent by weight of aerosol former on a dry weight basis of the aerosol-generating substrate, more preferably no more than 25 percent by weight on a dry weight basis, more preferably no more than 20 percent by weight on a dry weight basis. For example, the aerosol former content of the aerosolgenerating substrate may be between 5 percent and 30 percent by weight, or between 10 percent and 25 percent by weight, or between about 15 percent and about 20 percent by weight, on a dry weight basis. In such embodiments, the aerosol former content is therefore relatively low.

In other embodiments, the aerosol-generating substrate preferably comprises at least 40 percent by weight of aerosol former on a dry weight basis of the aerosol-generating substrate, more preferably at least 45 percent by weight on a dry weight basis, more preferably at least 50 percent by weight on a dry weight basis. In such embodiments, the aerosolgenerating substrate preferably comprises no more than 80 percent by weight of aerosol former on a dry weight basis of the aerosol-generating substrate, more preferably no more than 75 percent by weight on a dry weight basis, more preferably no more than 70 percent by weight on a dry weight basis. For example, the aerosol former content of the aerosolgenerating substrate may be between 40 percent and 80 percent by weight, or between 45 percent and 75 percent by weight, or between about 50 percent and about 70 percent by weight, on a dry weight basis. In such embodiments, the aerosol former content is therefore relatively high.

In some preferred embodiments, the aerosol-generating substrate comprises tobacco material. For example, the aerosol-generating substrate may comprise shredded tobacco material. For example, the shredded tobacco material may be in the form of cut filler, as described in more detail below. Alternatively, the shredded tobacco material may be in the form of a shredded sheet of homogenised tobacco material. Suitable homogenised tobacco materials for use in the present invention are described below.

Within the context of the present specification, the term “cut filler” is used to describe to a blend of shredded plant material, such as tobacco plant material, including, in particular, one or more of leaf lamina, processed stems and ribs, homogenised plant material.

The cut filler suitable to be used with the present invention generally may resemble cut filler used for conventional smoking articles. The cut width of the cut filler preferably may be between 0.3 millimetres and 2.0 millimetres, or between 0.5 millimetres and 1.2 millimetres, or between 0.6 millimetres and 0.9 millimetres.

Preferably, the strands have a length of between about 10 millimetres and about 40 millimetres before the strands are collated to form the rod of aerosol-generating substrate.

Preferably, the cut filler is soaked with the aerosol former. Soaking the cut filler can be done by spraying or by other suitable application methods. Preferably, the aerosol former in the cut filler comprises one or more of glycerol and propylene glycol. The aerosol former may consist of glycerol or propylene glycol or of a combination of glycerol and propylene glycol.

In other preferred embodiments, the aerosol-generating substrate comprises homogenised plant material, preferably a homogenised tobacco material.

As used herein, the term “homogenised plant material” encompasses any plant material formed by the agglomeration of particles of plant. For example, sheets or webs of homogenised tobacco material for the aerosol-generating substrates of the present invention may be formed by agglomerating particles of tobacco material obtained by pulverising, grinding or comminuting plant material and optionally one or more of tobacco leaf lamina and tobacco leaf stems. The homogenised plant material may be produced by casting, extrusion, paper making processes or other any other suitable processes known in the art.

The homogenised plant material can be provided in any suitable form.

In some embodiments, the homogenised plant material may be in the form of one or more sheets. As used herein with reference to the invention, the term “sheet” describes a laminar element having a width and length substantially greater than the thickness thereof.

The homogenised plant material may be in the form of a plurality of pellets or granules.

The homogenised plant material may be in the form of a plurality of strands, strips or shreds. As used herein, the term “strand” describes an elongate element of material having a length that is substantially greater than the width and thickness thereof.

The aerosol former content of the homogenised tobacco material is preferably within the ranges defined above for aerosol-generating substrate having a relatively low aerosol former content.

In other preferred embodiments, the aerosol-generating substrate is in the form of an aerosol-generating film comprising a cellulosic based film-forming agent, nicotine and the aerosol former. The aerosol-generating film may further comprise a cellulose based strengthening agent. The aerosol-generating film may further comprise water, preferably 30 percent by weight of less of water.

As used herein, the term “film” is used to describe a solid laminar element having a thickness that is less than the width or length thereof. The film may be self-supporting.

In the context of the present invention the term “cellulose based film-forming agent” is used to describe a cellulosic polymer capable, by itself or in the presence of an auxiliary thickening agent, of forming a continuous film, Preferably, the cellulose based film-forming agent is selected from the group consisting of hydroxypropyl methylcellulose (HPMC), methylcellulose (MC), ethylcellulose (EC), hydroxyethyl methyl cellulose (HEMC), hydroxyethyl cellulose (HEC), hydroxypropyl cellulose (HPC), and combinations thereof. In particularly preferred embodiments, the cellulose based film-forming agent is HPMC. The aerosol former content of the aerosol-generating film is within the ranges defined above for aerosol-generating substrates having a relatively high aerosol former content.

Suitable aerosol-generating films for use as the aerosol-generating substrate of aerosol-generating articles according to the invention are described in WO-A-2020/207733 and WO-A-2022/074157.

Preferably, the aerosol-generating film comprises between 0.5 percent and 10 percent by weight of nicotine, or between 1 percent and 8 percent by weight of nicotine, or between 2 percent and 6 percent by weight of nicotine, on a dry weight basis.

The aerosol-generating film may be a substantially tobacco-free aerosol-generating film.

In alternative embodiments of the invention, the aerosol-generating substrate may comprise a gel composition that includes nicotine, at least one gelling agent and the aerosol former. The gel composition is preferably substantially tobacco free.

The preferred weight ranges for nicotine in the gel composition are the same as those defined above in relation to aerosol-generating films.

Suitable gel compositions for use as the aerosol-generating substrate of aerosolgenerating articles according to the invention are described in WO-A-2021/170642.

The gel composition preferably comprises at least 50 percent by weight of aerosol former, more preferably at least 60 percent by weight, more preferably at least 70 percent by weight of aerosol former, on a dry weight basis. The gel composition may comprise up to 80 percent by weight of aerosol former. The aerosol former in the gel composition is preferably glycerol.

In certain embodiments of the invention, the aerosol-generating article further comprises one or more elongate susceptor elements within the rod of aerosol-generating substrate. For example, one or more elongate susceptor elements may be arranged substantially longitudinally within the rod of aerosol-generating substrate and in thermal contact with the aerosol-generating substrate.

As used herein with reference to the present invention, the term “susceptor element” refers to a material that can convert electromagnetic energy into heat.

Suitable susceptor elements for use in the aerosol-generating substrate of aerosolgenerating articles according to the present invention are described in WO-A-2021/170673.

Preferably, the rod of aerosol-generating substrate is circumscribed by a wrapper. The wrapper may be a paper wrapper or a non-paper wrapper.

Suitable paper wrappers for use in specific embodiments of the invention are known in the art and include, but are not limited to: cigarette papers; and filter plug wraps. Suitable non-paper wrappers for use in specific embodiments of the invention are known in the art and include, but are not limited to sheets of homogenised tobacco materials. As mentioned before, an aerosol-generating article as described above finds use in an aerosol-generating system comprising an electrically operated aerosol-generating device and the aerosol-generating article. The aerosol-generating device comprises means to heat the aerosol-generating substrate of the aerosol-generating article to a temperature sufficient to generate an aerosol from the aerosol generating substrate.

Preferably, the aerosol-generating device comprises a housing defining a cavity configured to receive the aerosol-generating article, and means for heating the aerosolgenerating substrate to a temperature sufficient to generate an aerosol from the aerosolgenerating substrate when the aerosol-generating article is received within the cavity.

The aerosol-generating device may be a handheld aerosol-generating device.

The aerosol-generating device may be an electrically-operated aerosol-generating device.

The aerosol-generating device may comprise a power supply and control electronics.

The aerosol-generating device may comprise a battery and control electronics.

The aerosol-generating device may be configured to heat the aerosol-generating substrate internally. That is, the aerosol-generating device may be configured to supply heat to the aerosol-generating substrate from a location internal to the aerosol-generating article.

For example, in some embodiments the aerosol-generating device comprises a heater element configured to be inserted into the aerosol-generating element when the aerosolgenerating article is received within the cavity of the aerosol-generating device.

In other embodiments, the aerosol-generating article comprises a susceptor element provided at a location within the aerosol-generating element, and the aerosol-generating device comprises an inductor coil positioned on or within the housing, a power supply of the aerosol-generating device being connected to the inductor coil and configured to provide a high frequency oscillating current to the inductor coil. This generates an alternating magnetic field that induces a voltage in the susceptor element. The induced voltage causes a current to flow in the susceptor element, and this current causes Joule heating of the susceptor element that, in turn, heats the aerosol-generating substrate. The aerosol-generating device may be capable of generating a fluctuating electromagnetic field having a magnetic field strength (H-field strength) of between 1 and 5 kilo amperes per metre (kA m), preferably between 2 and 3 kA/m, for example about 2.5 kA/m.

The aerosol-generating device may be configured to heat the aerosol-generating substrate externally. That is, the aerosol-generating device may be configured to supply heat to the aerosol-generating substrate from a location external to the aerosol-generating article. For example, in some embodiments the aerosol-generating device comprises a heater element located about a perimeter of the cavity and configured to heat the aerosol-generating substrate of the aerosol-generating article from an exterior of the aerosol-generating element of the aerosol-generating article.

The invention is defined in the claims. However, below there is provided a non- exhaustive list of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more features of another example, embodiment, or aspect described herein.

Example 1: An aerosol-generating article comprising: an aerosol-generating element comprising a nicotine-containing aerosol-generating substrate; a downstream section located downstream of the aerosol generating element, wherein said downstream section comprises a carboxylic acid selected from the group consisting of citric acid, benzoic acid, fumaric acid, lactic acid and combinations thereof.

Example 2: An aerosol generating article according to Example 1 , wherein the downstream section comprises a mouthpiece filter, the carboxylic acid being provided at a location in the mouthpiece filter.

Example 3: An aerosol generating article according to Example 1 , wherein the downstream section comprises a support element adjacent the aerosol generating element, the carboxylic acid being provided at a location in the support element.

Example 4: An aerosol generating substrate according to Example 1, wherein the downstream section comprises an aerosol cooling element adjacent the aerosol generating element, the carboxylic acid being provided at a location in the aerosol cooling element.

Example 5: An aerosol generating substrate according to Example 3, wherein the downstream section comprises an aerosol cooling element downstream of the support element, the carboxylic acid being provided at a location in the aerosol cooling element.

Example 6: An aerosol generating article according to any one of the preceding examples, the article further comprising an upstream section located upstream of the aerosol generating element.

Example 7: An aerosol generating article according to Example 7, wherein the upstream section is free of carboxylic acid.

Example 8: An aerosol generating article according to any one of the preceding examples wherein the aerosol-generating substrate comprises at least 10 percent by weight of an aerosol former.

Example 9: An aerosol-generating article according to any one of Examples 1 to 8, wherein the aerosol generating substrate comprises a plurality of shreds of tobacco material.

Example 10: An aerosol-generating article according to any one of Examples 1 to 8, wherein the aerosol generating substrate comprises one or more sheets of homogenised tobacco material. Example 11 : An aerosol-generating article according to any one of Examples 1 to 8, wherein the aerosol-generation substrate comprises a gel composition that includes nicotine, at least one gelling agent and an aerosol former.

Example 12: An aerosol-generating article according to any one of Examples 1 to 8, wherein the aerosol-generating substrate comprises hydroxypropyl methyl cellulose and one or more cellulose based strengthening agents.

Example 13: An aerosol-generating article according to any one of the preceding example, wherein the downstream section comprises at least 2.6 micromoles of the carboxylic acid.

Example 14: An aerosol-generating article according to any one of the preceding examples, wherein the downstream section comprises less than or equal to 1700 micromoles of the carboxylic acid.

Example 15: An aerosol-generating article according to any one of the preceding examples, wherein the downstream section comprises at least 0.5 milligrams of the carboxylic acid.

Example 16: An aerosol-generating article according to any one of the preceding examples, wherein the downstream section comprises less than or equal to 150 milligrams of the carboxylic acid.

Example 17: An aerosol generating article according to Examples 11 and 12 wherein the carboxylic acid is citric acid.

Example 18: An aerosol generating article according to any one of the preceding examples, wherein the downstream section comprises at least 1 .22 milligrams of benzoic acid.

Example 19: An aerosol generating article according to any one of the preceding examples, wherein the downstream section comprises less than or equal to 98 milligrams of benzoic acid.

Example 20: An aerosol generating article according to any one of the preceding examples, wherein the downstream section comprises at least 0.9 milligrams of lactic acid.

Example 21 : An aerosol generating article according to any one of the preceding examples, wherein the downstream section comprises less than or equal to 72 milligrams of lactic acid.

Example 22: An aerosol generating article according to any one of the preceding examples, wherein the downstream section comprises at least 1.16 milligrams of fumaric acid.

Example 23: An aerosol generating article according to any one of the preceding examples, wherein the downstream section comprises less than or equal to 93 milligrams of fumaric acid.

Example 24: An aerosol generating article according to Example 2, wherein the mouthpiece filter comprises at least 0.5 milligrams of carboxylic acid. Example 25: An aerosol generating article according to Example 2, wherein the mouthpiece filter comprises less than or equal to 150 milligrams of carboxylic acid.

Example 26: An aerosol-generating article according to Example 2, wherein the mouthpiece filter comprises at least 2.6 micromoles of the carboxylic acid.

Example 27: An aerosol-generating article according to Example 2, wherein the mouthpiece filter comprises less than or equal to 1700 micromoles of the carboxylic acid.

Example 28: An aerosol-generating article according to Example 2, wherein the mouthpiece filter comprises at least 0.5 micromoles of carboxylic acid per millimetre of mouthpiece filter.

Example 29: An aerosol-generating article according to Example 2, wherein the mouthpiece filter comprises less than or equal to 390 micromoles of carboxylic acid per millimetre of mouthpiece filter.

Example 30: An aerosol-generating article according to Example 2, wherein the mouthpiece filter comprises at least 0.024 milligrams of the carboxylic acid per cubic millimetre of the mouthpiece filter.

Example 31 : An aerosol-generating article according to Example 2 wherein the mouthpiece filter comprises less than or equal to 0.29 milligrams of the carboxylic acid per cubic millimetre of mouthpiece filter.

Example 32: An aerosol-generating article according to any one of the preceding examples wherein the downstream section comprises at least 0.5 milligrams of citric acid.

Example 33: an aerosol-generating article according to any one of the preceding examples, wherein the downstream section comprises less than or equal to 150 milligrams of the citric acid.

Example 34: An aerosol-generating article according to any one of the preceding examples, wherein the downstream section comprises at least 3 micromoles of citric acid.

Examples 35: An aerosol-generating article according to any one of the preceding examples, wherein the downstream section comprises less than or equal to 1300 micromoles of citric acid.

Example 36: An aerosol generating article according to Example 2, wherein the mouthpiece filter comprises at least 0.5 milligrams of citric acid.

Example 37: An aerosol generating article according to Example 2, wherein the mouthpiece filter comprises less than or equal to 150 milligrams of citric acid.

Example 38: An aerosol-generating article according to example 2, wherein the mouthpiece filter comprises at least 0.4 micromoles of citric acid per millimetre of mouthpiece filter. Example 39: An aerosol-generating article according to example 2, wherein the mouthpiece filter comprises less than or equal to 185 micromoles of citric acid per millimetre of mouthpiece filter.

Example 40: An aerosol generating article according to any one of the preceding examples comprising a ventilation zone at a location along the downstream section.

Example 41 : An aerosol generating article according to any one of the preceding examples wherein an overall length of the article is less than or equal to 60 millimetres.

Example 42: An aerosol generating article according to any one of the preceding examples wherein an overall length of the aerosol generating article is at least 50 millimetres.

Example 43: An aerosol generating article according to any preceding example wherein a diameter of the aerosol generating article is at least 5 millimetres.

Example 44: An aerosol generating article according to any one of the preceding examples wherein a diameter of the aerosol generating article is less than or equal to 7.3 millimetres.

Example 45: An aerosol generating article according to Example 2 wherein a length of the mouthpiece filter is at least 5 millimetres.

Example 46: An aerosol generating article according to Example 2 wherein a length of the mouthpiece filter is less than or equal to 12 millimetres.

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

Figure 1 is a cross-sectional view of an aerosol-generating article according to a first embodiment of the disclosure.

Figure 2 is a cross-sectional view of an aerosol-generating system comprising the aerosol-generating article of Figure 1 .

Figure 1 shows a schematic cross-sectional view of an aerosol-generating article 10 according to the present invention. The aerosol-generating article 10 has a substantially cylindrical shape. The aerosol-generating article 10 comprises a rod 12 of aerosol-generating substrate 12. The rod of aerosol-generating substrate 12 has a substantially cylindrical shape, and comprises a gathered sheet of homogenised tobacco. The article further comprises a downstream section 17, located downstream of the rod of aerosol-generating substrate 12. The downstream section 17 comprises a first hollow tubular element 14, a second hollow tubular element 15, and a mouthpiece filter 18. The mouthpiece filter 18 is at a proximal (downstream) end of the article 10.

The downstream section 17 comprises an intermediate section 17a located in between the rod of aerosol-generating substrate 12 and the mouthpiece filter 18. The intermediate section 17a comprises the first hollow tubular element 14 and the second hollow tubular element 15. The aerosol-generating article 10 further comprises an upstream element 11 at a distal (upstream) end of the article 10. The upstream element 11 is a solid cylindrical plug element having a filled cross-section. The upstream element 11 comprises cellulose acetate. The RTD of the upstream element is 5.5 millimetres of H2O.

A longitudinal axis 7 extends centrally along a longitudinal direction of the aerosolgenerating article 10. In this example, the length of the upstream element 11 is 5 millimetres. The upstream element 11 , the rod of aerosol-generating substrate 12, the first hollow tubular element 14, the second hollow tubular element 15, and the mouthpiece filter 18 are arranged end-to-end along the longitudinal axis 7.

The upstream element 11 , the rod of aerosol-generating substrate 12, the first hollow tubular element 14, the second hollow tubular element 15 and the mouthpiece filter 18 are circumscribed by a wrapper 16.

It will be appreciated that, in addition to the wrapper 16, one or more of the components of the aerosol-generating article 10 - namely the upstream element 11 , the rod of aerosolgenerating substrate 12 and the mouthpiece filter 18 - may each be circumscribed by an individual wrapper (not shown) which underlies the wrapper 16.

The rod of aerosol-generating substrate 12 has a rod length parallel to the longitudinal axis 7 of the aerosol-generating article 10 and a rod width perpendicular to the longitudinal axis 7 of the aerosol-generating article 10. The rod width is substantially uniform along the rod length. In this example, the rod width is 7 millimetres. In this example, the rod length is 11 millimetres. The resistance to draw (RTD) of the rod of aerosol-generating substrate 12 is 13.6 millimetres H2O. The length of the aerosol-generating article 10 is 45 millimetres. The resistance to draw (RTD) of the aerosol-generating article 10 is 46 millimetres of H2O.

The aerosol-generating article 10 illustrated in Figure 1 further comprises a susceptor element 12a arranged within the rod of aerosol-generating substrate 12. The susceptor element 12a is configured to be heated when penetrated by a varying magnetic field. The length of the susceptor element 12a is approximately equal to the rod length. That is, the length of the susceptor element 12a is 11 millimetres. The width of the susceptor element 12a is 4 millimetres and the thickness of the susceptor element 12a is 60 micrometres.

As mentioned above, the downstream section 17 comprises a mouthpiece filter 18, a second hollow tubular element 15, and a first hollow tubular element 14. The downstream section 17 extends between the rod of aerosol-generating substrate 12 and the downstream end of the aerosol-generating article 10. The downstream section 17 has a length of 29 millimetres. The second hollow tubular element 15 is downstream of the first hollow tubular element 14. The first hollow tubular element 14 is in the form a hollow acetate tube. The second hollow tubular element 15 is in the form of a hollow acetate tube. The first hollow tubular element 14 abuts the downstream end of the rod of aerosol-generating substrate 12. The length of the first hollow tubular element 14 is 8 millimetres. The length of the second hollow tubular element 15 is 9 millimetres.

The first hollow tubular element 14 comprises a lumen. The lumen of the first hollow tubular element 14 has a substantially circular cross-sectional shape. The second hollow tubular element 15 comprises a lumen. The lumen of the second hollow tubular element 15 has a substantially circular cross-sectional shape. The width of the lumen (inner width) of the second hollow tubular element 15 is larger than the width of the lumen (inner width) of the first hollow tubular element 14. The wall thickness of the second hollow tubular element 15 is smaller than the wall thickness of the first hollow tubular element 14. The wall thickness of the second hollow tubular element 15 is 1.05 millimetres. The wall thickness of the second hollow tubular element 14 is 1.9 millimetres. The width of each of the first hollow tubular element 14 and the second hollow tubular element 15 is 7.1 millimetres. The combined RTD of the first hollow tubular element 14 and the second hollow tubular element 15 is about 0 millimetres of H2O.

The second hollow tubular element 15 comprises a ventilation zone at a location along the second hollow tubular element 15. It will be appreciated that the ventilation zone could alternatively or in addition be provided at a location along the first hollow tubular element 14. The ventilation zone comprises one or more rows of ventilation holes 13 arranged circumferentially around the second hollow tubular element 15 in a cross-section that is substantially perpendicular to the longitudinal axis 7 of the aerosol-generating article 10. The ventilation holes 13 are perforations through the wall of the second hollow tubular element 15. A ventilation level of the aerosol-generating article 10 is about 50 percent. Each circumferential row of ventilation holes 13 comprises about 11 holes. The ventilation holes 13 extend through both the first wrapper 16 and the second wrapper 19 in a direction perpendicular to the longitudinal axis 7. The distance of the ventilation holes 13 from the downstream end of the article 10 is 18 millimetres.

The mouthpiece filter 18 is located at a downstream end of the aerosol-generating article 10 and comprises 1.5 milligrams of citric acid. The mouthpiece filter 18 abuts the downstream end of the second hollow tubular element 15. The mouthpiece filter 18 comprises a low-density, cellulose acetate filter segment. Citric acid has been added during manufacturing to the cellulose acetate tow in the form of an aqueous solution (for example, a 0.5 mol/litre aqueous solution of citric acid).

The RTD of the mouthpiece filter 18 is about 18 millimetres of H2O. The length of the mouthpiece filter 18 is 12 millimetres. The width of the mouthpiece filter 18 is 7.3 millimetres.

Figure 2 shows a schematic cross-sectional view of a portion of an aerosol-generating system 1000 comprising the aerosol-generating article 10 of Figure 1 and an aerosolgenerating device 100. In this embodiment, the aerosol-generating article 10 comprises a susceptor element 12a arranged within the rod of aerosol-generating substrate 12. The susceptor element 12a is configured to be heated when penetrated by a varying magnetic field.

The aerosol-generating device 100 further comprises an inductor coil 126 which circumscribes the device cavity 121 , and surrounds the susceptor element 12a. The inductor coil 126 is arranged to generate a varying magnetic field in the device cavity 121 , which penetrates the susceptor element 12a to inductively heat the susceptor element 12a.

The device cavity 121 is configured to receive at least a part of the aerosol-generating article 10. The distal end of the device cavity 121 has a closed end. The proximal end of the device cavity 121 has an open end. The aerosol-generating article 10 is insertable into the device cavity 121 via the open end of the device cavity 221.

In use, the user inserts the aerosol-generating article 10 into the device cavity 121 of the aerosol-generating device 100.

The aerosol-generating device 100 further comprises a power supply (not shown) and electronics (not shown) that are arranged to supply power to the inductor coil 226 to generate a varying magnetic field in the device cavity 121 to inductively heat the susceptor element 12a.

The susceptor element 12a heats the rod of aerosol-generating substrate 12 when the aerosol-generating article 10 is received in the device cavity 121. Such actuation of the inductor coil 126 may be manually operated or may occur automatically in response to a user drawing on the aerosol-generating article 10 when the aerosol-generating article 10 is inserted into the device cavity 121 .

The entire length of the rod of aerosol-generating substrate 12 is received in the device cavity 121. The device cavity 121 has a substantially circular cross-sectional shape. The device cavity 121 has substantially the same cross-sectional shape as the rod of aerosolgenerating substrate 12. The ventilation holes 13 of the second hollow tubular element 15 are not received in the device cavity 121.

During use, the inductor coil 126 is controlled to heat the susceptor element 12a within a defined operating temperature range, below a maximum operating temperature.

Tests were carried out on aerosol-generating articles in accordance with the present invention (Sample Articles) with a view to assessing the impact of the carboxylic acid provided in the mouthpiece filter on the composition of the aerosol delivered at the downstream end of the mouthpiece filter.

In more detail, aerosol-generating articles in accordance with the foregoing description provided with reference to the drawing of Figure 1 . As set out above, Sample Articles were prepared comprising a mouthpiece filter containing 1 .5 milligrams of citric acid.

In order to assess the impact of the citric acid on the aerosol composition, Comparative Articles were also prepared and subjected to the same tests, as will be discussed in more detail below. The Comparative Articles were substantially identical to the Sample Articles, but contained no citric acid.

Both Sample Articles and Comparative Articles were subjected to a smoking test under the Health Canada Intense (HCI) regime, which prescribes: a puff duration of 2 seconds, a period of 30 seconds between consecutive puffs, a puff volume of 55 millilitres, and a sinusoidal puff shape, with complete ventilation block. For each article subjected to the smoking test, the smoking cycle included 9 puffs.

Nicotine delivery was measured for both Sample Articles and Comparative Articles. The nicotine delivery measured on the Sample Articles was found to be consistently higher than the nicotine delivery measured on the Comparative Articles. In particular, an increase in the nicotine delivery in the range of 12 to 22 percent was detected.

Claims

1. An aerosol-generating article for generating an inhalable aerosol upon heating, the aerosol-generating article comprising: an aerosol-generating element comprising a nicotine-containing aerosolgenerating substrate; a downstream section located downstream of the aerosol generating element, wherein said downstream section comprises a carboxylic acid selected from the group consisting of citric acid, benzoic acid, fumaric acid, lactic acid and combinations thereof.

2. An aerosol generating article according to claim 1 , wherein the downstream section comprises a mouthpiece filter, the carboxylic acid being provided at a location within the mouthpiece filter.

3. An aerosol generating article according to claim 1 , wherein the downstream section comprises a support element adjacent the aerosol generating element, the carboxylic acid being provided at a location in the support element.

4. An aerosol generating substrate according to claim 1 , wherein the downstream section comprises an aerosol cooling element adjacent the aerosol generating element, the carboxylic acid being provided at a location in the aerosol cooling element.

5. An aerosol generating article according to any one of the preceding claims, the article further comprising an upstream section located upstream of the aerosol generating element.

6. An aerosol generating article according to claim 6, wherein the upstream section is free of carboxylic acid.

7. An aerosol-generating article according to any one of the preceding claims, wherein the downstream section comprises at least 0.5 milligrams of the carboxylic acid.

8. An aerosol-generating article according to claim 8, wherein the carboxylic acid is citric acid.

9. An aerosol generating article according to any one of the preceding claims comprising a ventilation zone at a location along the downstream section.

10. An aerosol generating article according to any one of the preceding claims wherein the aerosol-generating substrate comprises at least 10 percent by weight of an aerosol former.

11. An aerosol-generating article according to any preceding claim, wherein the aerosol generating substrate comprises at least one of: a plurality of shreds of tobacco material; one or more sheets of homogenised tobacco material; a gel composition that includes nicotine, at least one gelling agent and an aerosol former.

12. An aerosol generating article according to any one of the preceding claims wherein an overall length of the aerosol generating article is at least 50 millimetres.

13. An aerosol generating article according to any preceding claim wherein a diameter of the aerosol generating article is from 5 millimetres to 7.3 millimetres.

14. An aerosol generating article according to claim 2 wherein a length of the mouthpiece filter is from 5 millimetres to 12 millimetres.

15. An aerosol-generating system comprising an electrically operated aerosol-generating device and an aerosol-generating article according to any preceding claim, the aerosol-generating device comprising means to heat the aerosol-generating substrate to a temperature sufficient to generate an aerosol from the aerosol generating substrate.