Aerosol-generating article comprising a plug element comprising a processed paper material

Abstract

An aerosol-generating article (1000; 10; 100) comprises: an aerosol-generating substrate (1002; 12; 112); a downstream element (1008; 42; 150) provided downstream of the aerosol- generating substrate (1002; 12; 112) and in axial alignment with the aerosol-generating substrate. The downstream element (1008; 42; 150) comprises a plug element comprising a cellulosic filtration material comprising a processed paper material selected from the group consisting of glassine paper, parchment paper, and natural greaseproof paper.

Description

[0001] AEROSOL-GENERATING ARTICLE COMPRISING A PLUG ELEMENT COMPRISING A PROCESSED PAPER MATERIAL

[0002] The present invention relates to an aerosol-generating article comprising at least one element formed from a biodegradable filtration material. In particular, the present invention relates to an aerosol-generating article comprising a downstream element located downstream of, and in axial alignment with, an aerosol-generating substrate, the downstream element comprising a plug element formed from a biodegradable cellulosic filtration material.

[0003] Conventional aerosol-generating articles, such as filter cigarettes, typically comprise a cylindrical rod of tobacco cut filler surrounded by a paper wrapper and a cylindrical filter axially aligned, most often in an abutting end-to-end relationship, with the wrapped tobacco rod. The cylindrical filter typically comprises one or more plug elements of a fibrous filtration material, such as cellulose acetate tow, circumscribed by a paper plug wrap. Conventionally, the wrapped tobacco rod and the filter are joined by a band of tipping wrapper, normally formed of an opaque paper material that circumscribes the entire length of the filter and an adjacent portion of the wrapped tobacco rod. In known filter cigarettes, the filter is typically adapted for the removal of particulate and gaseous components of the mainstream smoke.

[0004] A number of aerosol-generating articles in which tobacco is heated rather than combusted have also been proposed in the art. In heated aerosol-generating articles, an aerosol is generated by heating an aerosol-generating substrate, such as tobacco. Known heated aerosol-generating articles include, for example, smoking articles in which an aerosol is generated by electrical heating or by the transfer of heat from a combustible fuel element or heat source to an aerosolgenerating substrate. During smoking, volatile compounds are released from the aerosolgenerating substrate by heat transfer from the heat source and entrained in air drawn through the smoking article. As the released compounds cool they condense to form an aerosol that is inhaled by the consumer.

[0005] Many known heated aerosol-generating articles comprise one or more elements formed of a fibrous filtration material and arranged downstream of the aerosol-generating substrate. For example, aerosol-generating articles have been proposed that comprise a support element arranged immediately downstream of the aerosol-generating substrate, wherein the support element may be configured to impart structural strength to the aerosol-generating article and to resist downstream movement of the aerosol-generating substrate when the aerosol-generating substrate cooperates with the aerosol-generating device during use. Further, aerosol-generating articles have been described that comprise an aerosol-cooling element arranged downstream of the aerosol-generating substrate and configured to lower the temperature of an aerosol produced upon heating the aerosol-generating substrate prior to the aerosol reaching the mouth end of the aerosol-generating article. WO 2013 / 120565 A2, for example, describes an aerosol-generating article comprising an aerosol-cooling element arranged downstream of a rod of aerosolgenerating substrate. The aerosol-cooling element may be formed from a sheet material, such as for example a sheet of polyethylene (PE), polypropylene (PP), polyvinylchloride (PVC), polyethylene terephthalate (PET), polylactic acid (PLA), cellulose acetate (CA), a metallic foil (like aluminium foil), paper or cardboard.

[0006] After an aerosol-generating article has been smoked and discarded, it would generally be desirable for its components - and particularly for any elements formed of fibrous filtration material - to break down as quickly as possible. However, cellulose acetate, the fibrous filtration material most ordinarily used in aerosol-generating articles, is not biodegradable, and can persist in the environment for years. As a result, used cigarette filters formed from cellulose acetate have a tendency to accumulate in the environment, and are among the most commonly retrieved plastic items in beach clean-up activities. Therefore, it would be desirable to provide a more sustainable alternative to cellulose acetate for producing aerosol-generating article components and in particular, filter or mouthpiece components.

[0007] To tackle the environmental impact caused by post-consumption waste of articles containing non-biodegradable plastic, discarded directly into the environment, certain jurisdictions are introducing legislations banning single-use plastic products (SLIPs). The term SLIPs denotes products made wholly or partly from plastic and that are typically intended to be used just once or for a short period of time before being disposed of. Accordingly, it would be generally desirable to replace single-use plastics in aerosol-generating articles with natural, biodegradable alternatives.

[0008] A wide variety of alternative materials have in fact already been proposed for use as filtration materials for aerosol-generating articles. However, in many cases, such alternative filtration materials have been found to be unable to provide an acceptable filtration efficiency and smoking experience for the consumer.

[0009] For example, filters made of cellulose pulp or paper material have been known for almost a century, as evidenced by GB 433048 A. Several processes for manufacturing paper filters have been disclosed over the years, such as the ones described in US 3238852 A. However, consumers have often reported that paper filters have an undesirable effect on the taste of the smoke or aerosol. This so-called “paper taste” has been described as being associated with a harsher, drier sensation compared to that provided by a known smoking article comprising a filter formed of cellulose acetate.

[0010] In other cases, such alternative filtration materials have been found to be lacking from a firmness and processability viewpoint. Furthermore, in many cases dispersible and degradable materials have been found to be unsuitable for use in the existing manufacturing processes, and would require too significant a modification of the existing methods and equipment to make their use commercially feasible.

[0011] Thus, it would be desirable to provide an aerosol-generating article comprising a component that is at least partially formed of a filtration material having increased biodegradability, but which provides a filtration efficiency that is comparable to that of a cellulose acetate tow. In particular, it would be desirable for the component to be formed of a biodegradable filtration material that can still effectively reduce or remove undesirable compounds from the aerosol generated from the substrate (for example, phenols).

[0012] Further, it would be desirable to provide such an aerosol-generating article that gives an acceptable sensory experience to the consumer. In particular, it would be desirable for the component to be formed of a biodegradable filtration material that has very little or no impact on the taste perceived by the consumer during use of the aerosol-generating article, and that generally does not adversely impact the smoking experience.

[0013] Even more than that, it would be desirable to provide such an aerosol-generating article that is less likely to provide a smoke or aerosol associated with a harsh, dry sensation for the consumer. For example, it would be desirable to provide an aerosol-generating article comprising an element comprising paper material that has reduced or no “paper taste”.

[0014] That is, without prejudice for the inherent taste variability associated with different types of aerosol-generating substrates, it would be desirable to provide such an aerosol-generating article that provides a smoke or aerosol having a taste profile comparable with that of existing, cellulose acetate filtered aerosol-generating articles.

[0015] In addition, it would be desirable to provide such an aerosol-generating article that can be readily manufactured using existing high speed techniques and apparatus requiring only minimal modifications.

[0016] Furthermore, it would be desirable for the filtration material to be such that it can be effectively formed into components that provide an acceptable appearance and feeling to the consumer. For example, it would be desirable for the filtration material to be such that it can be effectively formed into components for an aerosol-generating article, which provide a desirable density, firmness and resistance to draw (RTD).

[0017] The present disclosure relates to an aerosol-generating article. The aerosol-generating article may comprise an aerosol-generating substrate. Further, the aerosol-generating article may comprise a downstream element. The downstream element may be provided downstream of the aerosol-generating substrate. The downstream element may be provided in axial alignment with the aerosol-generating substrate.

[0018] The downstream element may comprise a plug element. The plug element may comprise a cellulosic filtration material. The cellulosic filtration material may comprise a processed paper material selected from the group consisting of glassine paper, parchment paper, and natural greaseproof paper.

[0019] According to a first aspect of the present invention, there is provided an aerosol-generating article comprising an aerosol-generating substrate; and a downstream element provided downstream of the aerosol-generating substrate and in axial alignment with the aerosolgenerating substrate. The downstream element comprises a plug element. The plug element comprises a cellulosic filtration material comprising a processed paper material selected from the group consisting of glassine paper, parchment paper, and natural greaseproof paper.

[0020] 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.

[0021] 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 upon heating volatile compounds that can generate an aerosol.

[0022] As used herein with reference to the invention, the term “aerosol” is used to describe a dispersion of solid particles, or liquid droplets, or a combination of solid particles and liquid droplets, in a gas. The aerosol may be visible or invisible. The aerosol may include vapours of substances that are ordinarily liquid or solid at room temperature as well as solid particles, or liquid droplets, or a combination of solid particles and liquid droplets.

[0023] As used herein with reference to the invention, the term “aerosol-generating device” is used to describe a device that interacts with the aerosol-generating substrate of the aerosolgenerating article to generate an aerosol.

[0024] 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.

[0025] 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.

[0026] 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 aerosol-generating 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 aerosol-generating article. During use, air is drawn through the aerosol-generating article in the longitudinal direction.

[0027] 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 aerosol-generating article in the longitudinal direction.

[0028] 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.

[0029] 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 crosssection, the width of the aerosol-generating article corresponds to the diameter of the aerosolgenerating 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.

[0030] As used herein with reference to the invention, the term “rod” is used to denote a generally cylindrical element having a substantially circular, oval or elliptical cross-section.

[0031] 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.

[0032] Unless otherwise specified, the resistance to draw (RTD) of a component or an aerosolgenerating article in accordance with the invention is measured in accordance with ISO 6565- 2015. The RTD refers the pressure required to force air through the full length of a component. The terms “pressure drop” or “draw resistance” of a component or article may also refer to the “resistance to draw”. Such terms generally refer to the measurements in accordance with ISO 6565-2015 and are normally carried out at a volumetric flow rate of about 17.5 millilitres per second at the output or downstream end of the measured component, at a temperature of about 22 degrees Celsius, a pressure of about 101 kPa (about 760 Torr) and a relative humidity of about 60%. The expression “resistance to draw (RTD) per unit length” of a particular component (or element) of the aerosol-generating article, such as the upstream element, the aerosol-generating element, and so forth, can be calculated by dividing the measured resistance to draw of the component by the total axial length of the component. The RTD per unit length refers to the pressure required to force air through a unit length of a component. Throughout the present disclosure, a unit length refers to a length of 1 millimetre. Accordingly, in order to derive the RTD per unit length of a particular component, a specimen of a particular length, 15 millimetres for example, of the component can be used in measurement. The RTD of such a specimen is measured in accordance with ISO 6565-2015. If, for example, the measured RTD is about 15 millimetres H2O, then the RTD per unit length of the component is about 1 millimetre H2O per millimetre. The RTD per unit length of the component is generally dependent on the structural properties of the material used for the component as well as the cross-sectional geometry or profile of the component, amongst other factors.

[0033] The aerosol stream generated during use of an aerosol-generating article is a complex mixture of chemicals, including semi-solid particles dispersed in a fluid matrix of vapours and permanent gases. As used herein with reference to the invention, the term "filtration efficiency" is used to describe the ability of an element comprising a filtration material to capture particulate matter contained in such aerosol stream. In practice, the term “filtration efficiency” denotes the fraction of the overall dry particulate matter carried in the aerosol stream that is retained within the element comprising filtration material during use.

[0034] The plug element of the downstream element of an aerosol-generating article in accordance with the present invention is air-permeable. As used herein, the term “air-permeable” is used to describe an entity which allows air to pass through it. The term “air-permeable” also encompasses a volume characteristic of a suitable material, either in relation to all or part of its volume; for example, a material having a porosity in all or part of the volume of the material.

[0035] In more detail, the term “air-permeable”, as used herein with reference to the plug element of an aerosol-generating article according to the present invention, denotes a plug element that is not blocked, plugged or sealed in a way to block air from passing through the air-permeable plug element.

[0036] The air-permeable plug element may be configured so as to enable flow along a desired airflow direction. For example, an air-permeable plug element may be configured so as to enable flow from a first end of the air-permeable plug element to a second end of the air-permeable plug element longitudinally opposite the first end of the air-permeable plug element.

[0037] To enable flow along a desired airflow direction, the air-permeable plug element may comprise one or more airflow channels extending through the air-permeable plug element. For example, the air-permeable plug element may comprise one or more airflow channels extending from a first end of the air-permeable plug element to a second end of the air-permeable plug element opposite the first end of the air-permeable plug element.

[0038] The one or more airflow channels of the air-permeable plug element may be arranged within the air-permeable body portion in regular and orderly fashion. For example, the air- permeable plug element may define a plurality of substantially longitudinal airflow channels extending parallel to each other.

[0039] The term “porosity” of an air-permeable body generally denotes the ratio of the volume of the accessible pores and voids to the bulk volume occupied by the body. The term “cross- sectional porosity” refers to the fraction of void space in a cross-sectional area of an air-permeable body, and particularly in a cross-sectional of a porous body, such as for example a cross-section of an air-permeable plug element of an aerosol-generating article in accordance with the present invention.

[0040] The cross-sectional porosity is the area fraction of void space of the transverse cross- sectional area of the air-permeable plug element. The transverse cross-sectional area of the air- permeable body portion is the area of the air-permeable plug element in the plane that is perpendicular to a desired airflow direction. In particular, with reference to an air-permeable plug element extending along a longitudinal axis, the transverse cross-sectional area of the air- permeable plug element may be the area of the air-permeable plug element in the plane that is perpendicular to the longitudinal axis of the air-permeable plug element.

[0041] The plug element will typically be substantially cylindrical, and so a transverse cross- sectional of the plug element will be substantially circular. However, more generally it will be possible to identify a longitudinal axis of the plug element and a transverse cross-section of the plug element will be in a plane substantially perpendicular to said longitudinal axis.

[0042] For example, the transverse cross-sectional porosity value may be determined using a digital imaging process. A digital image of a transverse cross-section of the plug element may be obtained, and a threshold may be applied to differentiate pixels that represent solid material from pixels that represent void. A void fraction of the entire cross-section may then be easily obtained. For example, with reference to a plug element of an aerosol-generating article in accordance with the present invention, the characteristics of which will be described in more detail below, a suitable image of a transverse cross-section of the plug element can be obtained by photographing the transverse cross-section of the plug element using a digital camera or by scanning the transverse cross-section of the plug element using a scanner. Equally, a photograph may be taken using a conventional camera and the image produced may then be scanned and transformed into a digital image.

[0043] For a plug element formed from a sheet, which is gathered or otherwise processed to be formed into rod-shape, the transverse cross-sectional porosity of the plug element may also be calculated based on geometric parameters of the sheet. In more detail, for a sheet having a thickness (t) and a width (w) the cross-sectional area presented by an edge of the sheet material is given by the width multiplied by the thickness. For example, in a specific embodiment of a sheet having a thickness of 50 micrometres (± 2 micrometres) and a width of 230 millimetres, the cross-sectional area is approximately 1.15 x 10'5m2(this may be denoted the first area). The sheet may be gathered to form a rod having a diameter (d). The inner area of the rod is given by the formula (d / 2)2TT. Assuming a diameter of the rod of 6.9 millimetres, the inner area of the rod is 3.78 x 10'5m2(this may be denoted the second area). The ratio of the first and second area based on the above examples is approximately 0.304. This ratio is multiplied by 100 and the quotient is subtracted from 100% to arrive at the porosity, which is approximately 70% for the specific figures given here. Clearly, the thickness and width of a sheet material may be varied. Likewise, the inner diameter of a rod may be varied. It will now be obvious to one of ordinary skill in the art that with a known thickness and width of a material, in addition to the diameter of the rod, the porosity can be calculated in the above manner. Accordingly, where a sheet of material has a known thickness and length, and is crimped and gathered along the length, the space filled by the material can be determined. The unfilled space may be calculated, for example, by taking the inner diameter of the rod. The porosity or unfilled space within the rod can then be calculated as a percentage of the total area of space within the rod from these calculations.

[0044] As used herein with reference to the invention, the term "specific surface area" is used to denote the total surface area of a solid material per unit of mass. Specific surface area is generally dependent on the size of the particles forming a solid material, as well as on the structure and porosity, pore size distribution, of the solid material.

[0045] As described briefly above, the plug element comprises a cellulosic filtration material comprising a processed paper material selected from the group consisting of glassine paper, parchment paper, and natural greaseproof paper.

[0046] For the purposes of the invention, the term “paper material” generally denotes a web of cellulosic fibres in sheet form. As used herein with reference to the invention, the term “sheet” is used to describe a laminar element having a width and a length substantially greater than a thickness thereof. The sheet may have a thickness ranging from 0.03 to 2 millimetres and a basis weight of from 10 grams per square metre to 200 grams per square metre. The term “paper” is typically used to denote one such web of cellulosic fibres in sheet form, wherein the sheet has a thickness ranging from 0.03 to 0.20 millimetres.

[0047] To form the web, an aqueous slurry of pulp fibres is drained through a sieve-like screen, so that a mat of randomly interwoven fibres is laid down. Water is further removed from this mat by pressing, optionally assisted by suction or vacuum, or by heating, or both. Once the drying process is complete, a generally flat and uniform sheet of paper material is obtained. The term “pulp” is used to denote a lignocellulosic fibrous material prepared by chemically or mechanically separating cellulose fibres from wood, fibre crops, waste paper, or rags. Lignocellulose is composed primarily of cellulose, hemicellulose and lignin.

[0048] The term “cellulose” denotes an organic compound with the formula (CeHwOs A polysaccharide consisting of a linear chain of several hundreds to many thousands of D-glucose units joined by a glycosidic-bond, cellulose is a structural component of the primary cell wall of green plants and many algae.

[0049] The term “hemicellulose” identifies a groups of polysaccharides typically present with cellulose in almost all terrestrial plant cell walls. The hemicellulose polysaccharides are shorter than cellulose and typically branched. From a chemical viewpoint, while cellulose is derived exclusively from glucose, hemicellulose polysaccharides include both five-carbon sugars (xylose and arabinose) and six-carbon sugars (mannose and galactose on top of glucose). Additionally, acidified forms of sugars - such as glucuronic acid and galacturonic acid - may be found in hemicellulose.

[0050] The term “lignin” identifies a group of highly heterogeneous polymers derived from a few Precursor lignols. Its heterogeneity arises from the diversity and variable degree of crosslinking between these lignols. For example, the relative amounts of the precursor lignols generally varies depending on the plant source. The lignin polymers typically form key structural materials in the support tissues of plant, and especially in the cell walls of wood and bark, and are also found in red algae. Lignin fills gaps in the cell walls between cellulose, hemicellulose and pectin components, lending rigidity by virtue of the cross-linking between the lignol molecules.

[0051] Lignin is understood to hinder the formation of hydrogen bonds between cellulose fibres. Therefore, some pulping processes are designed to remove as much lignin as possible, as this is understood to provide stronger paper by facilitating inter-fibre bonding. Other pulping processes aim instead at separating the fibres. Pulp intended for use in fine papers typically undergoes a papermaking process aiming at both removing the lignin and separating the fibres.

[0052] However, irrespective of the specific pulping process used, the lignin gets more resistant to removal as the pulping proceeds, while the cellulose fibres become more vulnerable to the chemicals used or to the mechanical pulping or both. Therefore, at the end of the papermaking process, some lignin is ordinarily present in all paper materials, as the complete removal of lignin would in all likelihood be accompanied by excessive cellulose loss or by some less than desirable degradation of the mechanical properties of the cellulose fibres.

[0053] Glassine paper, parchment paper and natural greaseproof paper (such as Nordic Paper Perga® or Superperga®) are processed paper materials with a comparatively high density, typically close to or higher than 1 gram / cubic centimetre. Preferred values of density for the processed paper material used in the plug of aerosol-generating articles in accordance with the present invention will be discussed in more detail below.

[0054] To achieve such a comparatively high density values falling within these ranges, the sheet of paper material obtained from pressing and drying the mat of randomly interwoven fibres, as described above, is then typically thinned, and the surface of the sheet of paper material is typically smoothed by pressing the sheet of paper material between metal cylinders or rollers, which are also referred to as calenders. This operation, denoted as “calendering”, is typically the last step of the papermaking process before the paper material is cut to standard sizes. Calendering may be carried out at high temperature, optionally in presence of plasticisers or mineral fillers (for example, calcium carbonate).

[0055] As used herein with reference to the present invention, the term “glassine paper” is used to denote a paper material that has been subjected to a supercalendering process. In fact, glassine paper is often also referred to as “supercalendered paper”.

[0056] To make glassine paper, after the sheet of paper material has been thinned by the calendering process, the sheet of paper is fed through an additional set of calenders called “supercalender”. The supercalender consists of several cylinders alternating between polished metal and soft resilient surfaces (also called “nips”), typically provided as fibre-covered cylinders. The supercalender runs at high speed and applies pressure, heat, and friction to the sheet of paper material. Once compressed, the fibres defining the soft resilient surfaces struggle to return to their original dimensions, and thus they buff the sheet of paper material passing through the nips.

[0057] The force generated by each progressive nip is understood to polish both surfaces of the sheet of paper material. Without wishing to be bound by theory, this is understood to be due to the supercalendering process breaking down the capillaries of the cellulose fibres at a cellular level. This imparts the sheet of paper material undergoing supercalendering a highly closed surface, along with improved density and very low porosity. As a result, glassine paper is typically more resistant to grease and moisture than non-supercalendered paper materials. Additionally, both sides of a sheet of glassine paper tend to have a smooth and glossy finish.

[0058] Further details about how glassine paper can be manufactured can be found in US 2792765 A.

[0059] As used herein with reference to the present invention, the term “parchment paper” is used to denote a paper material which has been treated with sulphuric acid to impart the paper material enhanced non-stick or release properties. To make parchment paper, the sheet of paper pulp is run through a bath of sulphuric acid, which has the effect of partially dissolving and fusing together the pulp fibres. Without wishing to be bound by theory, this is understood to form a sulphurised, cross-linked structure, which displays comparatively high density in combination with good heat resistance, grease resistance, water resistance, and generally low surface energy. At the end of its manufacturing process, parchment paper - which is also at times referred to as “vegetable parchment” - has an appearance similar to that of parchment.

[0060] Further details about how parchment paper can be manufactured can be found in US 1334843 A.

[0061] The term “greaseproof paper” is commonly used to refer to a refined paper material that has been made impermeable to oil or grease. These properties make greaseproof paper particularly suitable for use in cooking and food packaging. As used herein with reference to the present invention, the term “natural greaseproof paper” is used to denote a greaseproof paper obtained by subjecting the paper material to a beating process, whereby a great number of bonding sites are formed on each fibre, which in turn enhances the overall density of the paper material. Without wishing to be bound by theory, it is understood that this process imparts the paper material a closed surface structure with a rather small number of large surface pores. Thus, natural greaseproof paper combines comparatively high density with a very low porosity. For example, Scandinavian company Nordic Paper offers for sale natural greaseproof paper whose barrier properties make it an alternative to paper materials treated with fluorochemicals.

[0062] As used herein, the term “phenols” refers to a class of chemical compounds consisting of a hydroxyl group ( — OH) bonded directly to an aromatic hydrocarbon group. The phenol group includes phenol, catechol, m+P cresols, and o-cresol.

[0063] As used herein, with reference to the present invention, the term “additive for reducing phenols” is used to denote any additive, which, when added to a mouthpiece of an aerosolgenerating article, is capable of reducing the level of at least one of phenol, catechol, m+P cresols, and o-cresol in the smoke or aerosol, when subjected to a standard smoking test.

[0064] As used herein, the term “flue gases” is used to denote certain gaseous products generated by the combustion or pyrolysis of an aerosol-generating substrate.

[0065] The present invention provides an improved aerosol-generating article comprising at least one downstream element, the downstream element comprising a plug element formed of a cellulosic filtration material comprising a processed paper material selected from the group consisting of glassine paper, parchment paper, and natural greaseproof paper. Aerosolgenerating articles according to the present invention can therefore advantageously be formed of more sustainable materials, containing a reduced or zero level of single use plastics. In particular, aerosol-generating articles according to the invention use one of the selected processed paper materials listed above in place of other more conventional materials, such as cellulose acetate fibres, to form elements such as filtration elements, thereby significantly improving the biodegradability of the aerosol-generating article. First of all, using a paper material, which comprises randomly oriented cellulose fibres, advantageously facilitates degradation of the plug element. This is because the randomly oriented fibres can more easily disperse after the plug element has been discarded, particularly when compared with the substantially continuous filaments of traditional cellulose acetate tow filters. Increased dispersion of the fibres increases the exposure of the individual fibres to the environment, thus increasing the rate at which the plug element degrades.

[0066] Subjecting the paper material to a supercalendering process (as in the case of glassine paper) or to a high degree of beating (as in the case of natural greaseproof paper) or to sulphuric acid treatment (as in the case of parchment paper) has advantageously been found to significantly lessen the impact of the filtration material of the downstream element on the taste of the smoke or aerosol provided to the consumer during of the aerosol-generating article. In fact, forming the plug element from a cellulosic filtration material comprising one of the selected paper materials listed above has been observed to desirably reduce or even eliminate any harsh and dry sensation referred to by consumers as “paper taste” and often associated with smoke or aerosol that has flown through filter elements made of other paper materials not treated as described above.

[0067] Advantageously, as will be described in more detail below, parameters such as porosity, surface area and geometry of the downstream element can be adjusted with a view to controlling the RTD of the downstream element and of the aerosol-generating article as a whole, as well as the ability of the downstream element to reduce the temperature of the smoke or aerosol provided to the consumer during of the aerosol-generating article.

[0068] Further, in certain embodiments, the application of selected additive coatings to the processed paper material has advantageously been found to further improve the filtration properties of the downstream element, particularly with reference to the ability of the downstream element to reduce certain undesirable compounds from the mainstream smoke or aerosol, compared to the use of both non-supercalendered and supercalendered paper materials. For example, the composition of the additive coating can advantageously be modified to optimise the filtration efficiency of the downstream element, such that it can achieve a similar reduction in phenols and other undesirable compounds as a conventional cellulose acetate tow.

[0069] In the plug element, the processed paper material is typically in the form of a sheet, which is gathered or otherwise processed to be formed into rod-shape. As used herein with reference to the invention, the term “gathered” denotes that a sheet is compressed or constricted substantially transversely relative to a longitudinal axis of the plug element.

[0070] Alternatively, the web or sheet of processed paper material may be wound to form a substantially cylindrical hollow tubular element. By varying the number of turns or convolutions, one may adjust the thickness of the hollow tubular element. The plug element may comprise a single sheet of processed paper material that is gathered or otherwise processed to be formed into rod shape. Alternatively, the plug element may comprise two or more sheets of processed paper material that are gathered or otherwise processed together to be formed into rod shape. For example, two or more sheets of processed paper material may be laid on top of each other and gathered or otherwise processed at once to form the plug element. Two or more sheets of processed paper material may also be gathered or otherwise processed independently, in parallel to each other, and then combined to form the plug element.

[0071] The plug element may, as an alternative, comprise a plurality of sheets of processed paper material stacked on top of each other. The resulting stack may have a thickness of up to 10 millimetres. The stack may be slitted into rod-shaped elements to form plug elements for use in an aerosol-generating article according to the present invention.

[0072] Prior to being formed into a rod or hollow tubular element, the web or sheet of processed paper material may be textured. Texturing of the web or sheet of paper material may advantageously facilitate gathering of the sheet into a rod.

[0073] As used herein, the term “textured sheet” denotes a sheet that has been crimped, embossed, debossed, perforated or otherwise deformed. Textured sheets of processed paper material may therefore comprise a plurality of spaced-apart indentations, protrusions, perforations or a combination thereof.

[0074] As used herein, the term “crimped sheet” is intended to be synonymous with the term “creped sheet” and denotes a sheet having a plurality of substantially parallel ridges or corrugations. Preferably, in a plug element formed by gathering a crimped sheet of processed paper material, the crimped sheet has a plurality of ridges or corrugations substantially parallel to a cylindrical axis of the plug element. This advantageously facilitates gathering of the crimped sheet of processed paper material to form a rod. However, it will be appreciated that crimped sheets of processed paper material for use in plug elements of aerosol-generating articles as described herein may alternatively or in addition have a plurality of substantially parallel ridges or corrugations disposed at an acute or obtuse angle to the longitudinal axis of the plug element. In general, the provision of the plurality of ridges or corrugations increases a surface area of a plug element formed from one such crimped sheet, which may enhance the filtration efficiency of the plug by facilitating contact between the aerosol or smoke flowing through the plug element and the additive coating.

[0075] In certain embodiments, sheets of processed paper material for use in forming plug elements as described herein may be substantially evenly textured over substantially their entire surface. For example, crimped sheets of processed paper material for use in forming plug elements as described herein may comprise a plurality of substantially parallel ridges or corrugations that are substantially evenly spaced-apart across the width of the sheet.

[0076] Gathering or winding the sheet of processed paper material to form the plug element has the benefit that by adjusting the number of convolutions or how tight the sheet is gathered it is possible to ensure that the plug element displays the required resistance to mechanical deformation, such that in the aerosol-generating article the plug element can withstand being grasped by the consumer during smoking.

[0077] In an aerosol-generating article according to the present invention, the processed paper material may have a density of at least 0.65 grams / cubic centimetre. Preferably, the glassine paper has a density of at least 0.75 grams / cubic centimetre. More preferably, the processed paper material has a density of at least 0.85 grams / cubic centimetre. Even more preferably, the processed paper material has a density of at least 0.95 grams / cubic centimetre.

[0078] In particularly preferred embodiments, the processed paper material has a density of at least 1 gram / cubic centimetre.

[0079] In an aerosol-generating article according to the present invention, the processed paper material may have a density up to 1.55 grams / cubic centimetre. Preferably, the processed paper material has a density of less than or equal to 1.45 grams / cubic centimetre. More preferably, the processed paper material has a density of less than or equal to 1.35 grams / cubic centimetre. Even more preferably, the processed paper material has a density of less than or equal to 1 .25 grams / cubic centimetre.

[0080] In particularly preferred embodiments, the processed paper material has a density of less than or equal to 1.15 grams / cubic centimetre.

[0081] For example, the processed paper material may have a density from 0.65 grams / cubic centimetre to 1.55 grams / cubic centimetre, preferably from 0.65 grams / cubic centimetre to 1.45 grams / cubic centimetre, more preferably from 0.65 grams / cubic centimetre to 1.35 grams / cubic centimetre, even more preferably from 0.65 grams / cubic centimetre to 1.25 grams / cubic centimetre, and particularly preferably from 0.65 grams / cubic centimetre to 1.15 grams / cubic centimetre.

[0082] For example, the processed paper material may have a density from 0.75 grams / cubic centimetre to 1.55 grams / cubic centimetre, preferably from 0.75 grams / cubic centimetre to 1.45 grams / cubic centimetre, more preferably from 0.75 grams / cubic centimetre to 1.35 grams / cubic centimetre, even more preferably from 0.75 grams / cubic centimetre to 1.25 grams / cubic centimetre, and particularly preferably from 0.75 grams / cubic centimetre to 1.15 grams / cubic centimetre.

[0083] For example, the processed paper material may have a density from 0.85 grams / cubic centimetre to 1.55 grams / cubic centimetre, preferably from 0.85 grams / cubic centimetre to 1.45 grams / cubic centimetre, more preferably from 0.85 grams / cubic centimetre to 1.35 grams / cubic centimetre, even more preferably from 0.85 grams / cubic centimetre to 1.25 grams / cubic centimetre, and particularly preferably from 0.85 grams / cubic centimetre to 1.15 grams / cubic centimetre.

[0084] For example, the processed paper material may have a density from 0.95 grams / cubic centimetre to 1.55 grams / cubic centimetre, preferably from 0.95 grams / cubic centimetre to 1.45 grams / cubic centimetre, more preferably from 0.95 grams / cubic centimetre to 1.35 grams / cubic centimetre, even more preferably from 0.95 grams / cubic centimetre to 1.25 grams / cubic centimetre, and particularly preferably from 0.95 grams / cubic centimetre to 1.15 grams / cubic centimetre.

[0085] For example, the processed paper material may have a density from 1 gram / cubic centimetre to 1.55 grams / cubic centimetre, preferably from 1 gram / cubic centimetre to 1.45 grams / cubic centimetre, more preferably from 1 gram / cubic centimetre to 1.35 grams / cubic centimetre, even more preferably from 1 gram / cubic centimetre to 1 .25 grams / cubic centimetre, and particularly preferably from 1 gram / cubic centimetre to 1.15 grams / cubic centimetre.

[0086] In an aerosol-generating article according to the present invention, the processed paper material may have a grammage of at least 35 gsm. Preferably, the processed paper material has a grammage of at least 40 gsm. More preferably, the processed paper material has a grammage of at least 45 gsm. Even more preferably, the processed paper material has a grammage of at least 50 gsm.

[0087] In an aerosol-generating article according to the present invention, the processed paper material may have a grammage of up to 110 gsm. Preferably, the processed paper material has a grammage of less than or equal to 100 gsm. More preferably, the processed paper material has a grammage of less than or equal to 80 gsm. Even more preferably, the processed paper material has a grammage of less than or equal to 60 gsm.

[0088] For example, the processed paper material may have a grammage from 35 gsm to 110 gsm, preferably from 35 gsm to 100 gsm, more preferably from 35 gsm to 80 gsm, even more preferably from 35 gsm to 60 gsm.

[0089] For example, the processed paper material may have a grammage from 40 gsm to 110 gsm, preferably from 40 gsm to 100 gsm, more preferably from 40 gsm to 80 gsm, even more preferably from 40 gsm to 60 gsm.

[0090] For example, the processed paper material may have a grammage from 45 gsm to 110 gsm, preferably from 45 gsm to 100 gsm, more preferably from 45 gsm to 80 gsm, even more preferably from 45 gsm to 60 gsm. For example, the processed paper material may have a grammage from 50 gsm to 110 gsm, preferably from 50 gsm to 100 gsm, more preferably from 50 gsm to 80 gsm, even more preferably from 50 gsm to 60 gsm.

[0091] The grammage of the processed paper material may be selected based on a balance between the ability of the plug element to withstand a compressive load during use, and the need to preserve a certain pliability of the sheet of processed paper material to be able to form it into a desired shape. Further, the grammage of the processed paper material may be selected such that the plug element is able to resist deformation during storage, transportation and use of the aerosol-generating article.

[0092] As described briefly above, the processed paper material may be in the form of a sheet having a thickness of up to 800 micrometres. Preferably, the sheet of processed paper material has a thickness of less than or equal to 600 micrometres. More preferably, the sheet of processed paper material has a thickness of less than or equal to 600 micrometres. Even more preferably, the sheet of processed paper material has a thickness of less than or equal to 500 micrometres.

[0093] In preferred embodiments, the sheet of processed paper material material has a thickness of less than or equal to 300 micrometres, preferably less than or equal to 200 micrometres, more preferably less than or equal to 100 micrometres.

[0094] The sheet of processed paper material may have a thickness of at least 10 micrometres. Preferably, the sheet of processed paper material has a thickness of at least 15 micrometres. More preferably, the sheet of processed paper material has a thickness of at least 20 micrometres. Even more preferably, the sheet of processed paper material has a thickness of at least 30 micrometres.

[0095] In preferred embodiments, the sheet of processed paper material has a thickness of at least 40 micrometres, preferably at least 50 micrometres, more preferably at least 60 micrometres.

[0096] The thickness of the sheet of processed paper material may be selected to ensure a certain pliability of the sheet, so as to enable one or more of crimping, gathering, pleating, and folding of the sheet.

[0097] The plug element may have a weight of less than or equal to about 100 milligrams, less than or equal to about 75 milligrams, or less than or equal to about 50 milligrams.

[0098] The plug element may have a weight of at least about 10 milligrams, at least about 15 milligrams, or at least about 20 milligrams.

[0099] The plug element may have a weight of between about 10 milligrams and about 100 milligrams, between about 10 milligrams and about 75 milligrams, or between about 10 milligrams and about 50 milligrams. The plug element may have a weight of between about 15 milligrams and about 100 milligrams, between about 15 milligrams and about 75 milligrams, or between about 15 milligrams and about 50 milligrams.

[0100] The plug element may have a weight of between about 20 milligrams and about 100 milligrams, between about 20 milligrams and about 75 milligrams, or between about 20 milligrams and about 50 milligrams.

[0101] The plug element may have an average weight per unit length of less than or equal to about 20 milligrams per millimetre, less than or equal to about 15 milligrams per millimetre, or less than or equal to about 10 milligrams per millimetre.

[0102] As used herein with reference to the invention, the average weight per unit length of the plug element is equal to the weight of the plug element divided by the length of the plug element. For example, where the plug element has a weight of 25 milligrams and a length of 5 millimetres, the average weight per unit length of the plug element is 5 milligrams per millimetre.

[0103] The plug element may have an average weight per unit length of at least about 2 milligrams per millimetre, at least about 3 milligrams per millimetre, or at least about 4 milligrams per millimetre.

[0104] The plug element may have an average weight per unit length of between about

[0105] 2 milligrams per millimetre and about 20 milligrams per millimetre, between about 2 milligrams per millimetre and about 15 milligrams per millimetre, or between about2 milligrams per millimetre and about 10 milligrams per millimetre.

[0106] The plug element may have an average weight per unit length of between about

[0107] 3 milligrams per millimetre and about 20 milligrams per millimetre, between about 3 milligrams per millimetre and about 15 milligrams per millimetre, or between about 3 milligrams per millimetre and about 10 milligrams per millimetre.

[0108] The plug element may have an average weight per unit length of between about

[0109] 4 milligrams per millimetre and about 20 milligrams per millimetre, between about 4 milligrams per millimetre and about 15 milligrams per millimetre, or between about 4 milligrams per millimetre and about 10 milligrams per millimetre.

[0110] In some embodiments, the processed paper material is glassine paper manufactured from highly refined kraft pulp or anthraquinone soda pulp.

[0111] As part of the papermaking process, fillers may be added to the pulp fibres prior to the formation of the web. Thus, in an aerosol-generating article according to the present invention, the processed paper material may comprise one or more fillers.

[0112] Fillers used in the papermaking process are ordinarily inorganic, particulate substances, typically in the size range of 0.1 to 10 micrometres that may impart certain desirable properties to the paper material. For example, fillers may have an impact on the structure, appearance (for example, brightness and opacity), density, tensile strength and other measurable properties of the paper material. Examples of commonly used papermaking fillers include clay, limestone, chalk, talc, calcite (calcium carbonate), rutile (titanium dioxide), calcium sulphate, amorphous silica.

[0113] As a result of the supercalendering process, glassine paper is translucent, unless dyes are added to colour it or make it opaque. Glassine paper for use in the manufacture of a plug element of an aerosol-generating article in accordance with the present invention may include one or more of the papermaking fillers described above. The addition of such commonly used papermaking fillers may be desirable in that it may alter the visual impact of glassine paper by at least partly reducing its translucency.

[0114] In some preferred embodiments, the glassine paper comprises calcium carbonate. On top of being highly compatible with the supercalendering process, the additional of calcium carbonate may advantageously further increase the density of the glassine paper.

[0115] Preferably, the cellulosic filtration material does not include cellulose acetate fibres or any other fibres formed of non-biodegradable polymers.

[0116] In an aerosol-generating article according to the present invention, the cellulosic filtration material may comprise an additive coating applied to the processed paper material.

[0117] The additive coating may comprise at least 5 percent by weight of an additive for reducing phenols.

[0118] In plug elements for use in aerosol-generating articles in accordance with the present invention, the additive coating may cover at least part of the external surface of at least one side of the sheet of processed paper material. Preferably, the additive coating covers at least part of the external surface of both sides of the sheet of processed paper material.

[0119] The additive coating may be applied over a part of the external surface of at least one side of the sheet of processed paper material. Preferably, the additive coating is applied over a part of the external surface of both sides of the sheet of processed paper material.

[0120] Alternatively, the additive coating may be applied over substantially all of the external surface of at least one side of the sheet of processed paper material. Preferably, the additive coating may be applied over substantially all of the external surface of at least one side of the sheet of processed paper material.

[0121] Thus, in aerosol-generating articles in accordance with the present invention, the additive coating may be applied to the processed paper material to form a defined layer on at least part of the external surface of at least one side of the sheet of processed paper material. In some embodiments, the additive coating may be applied to the processed paper material to form a defined layer on at least part of the external surface of both sides of the processed paper material. For example, this may be achieved by applying the additive coating to the processed paper material by a conventional printing process (for example, gravure printing or flexographic printing) or by a known coating process (for example, curtain coating, reverse gravure, semi-flexo, rodcoating, blade coating, comma coating, slot die coating).

[0122] The application of the additive coating to the external surface of the processed paper material advantageously maximises the contact between the mainstream smoke or aerosol passing through the downstream element during use and the additive coating. This in turn maximises the capability of the additive coating to reduce phenols and other undesirable compounds in the smoke or aerosol.

[0123] However, depending on the porosity of the paper material and due to the natural tendency of the paper material to absorb liquids such as water, applying the additive coating to the processed paper material may result in at least some of the additive coating permeating into the processed paper material, so that at least some of the volume of the processed paper material is soaked with additive coating. This may occur, in particular, if the additive coating is provided in the form of an aqueous solution or dispersion.

[0124] Therefore, in aerosol-generating articles in accordance with the present invention, the additive coating may alternatively, or additionally, be applied to the processed paper material not so much to form a defined layer on at least part of the external surface of at least one side of the processed paper material, but rather to at least partly impregnate the volume of the processed paper material. In such case, the coating additive does not form a defined layer on the external surface of the processed paper material. Instead, the coating additive is absorbed into the processed paper material and, upon drying, forms a deposit onto the fibrous fraction of the processed paper material (that is, on the individual cellulose fibres contained in the processed paper material). For example, at least partial impregnation of the processed paper material with the additive coating may be achieved by technologies such as “dip and squeeze”, spray application, comma application, or by using conventional or film type size presses or blade applicators.

[0125] The provision of such deposit of additive coating on the cellulose fibres of the processed paper material advantageously ensures that the mainstream smoke or aerosol passing through the downstream element contacts the additive coating during use, and this interaction promotes the reduction of phenols and other undesirable compounds in the smoke or aerosol.

[0126] Thus, in certain embodiments of the aerosol-generating article according to the present invention the plug element may comprise a cellulosic filtration material wherein the additive coating forms a defined layer on at least part of the external surface of at least one side of the processed paper material. In other embodiments of the aerosol-generating article according to the present invention the plug element may comprise a cellulosic filtration material wherein the additive coating has been absorbed into the processed paper material and at least partly impregnates the volume of the processed paper material. In further embodiments of the aerosolgenerating article according to the present invention the plug element may comprise a cellulosic filtration material wherein the additive coating has both been absorbed into the processed paper material, and therefore at least partly impregnates the volume of the processed paper material, and formed a defined layer on at least part of the external surface of at least one side of the processed paper material.

[0127] The at least one additive for reducing phenols may be an ester of a polycarboxylic acid, such as for example an ester of oxalic acid, malonic acid, succinic acid, citric acid, isocitric acid. In preferred embodiments, the at least one additive for reducing phenols is an ester of citric acid, for example triethyl citrate (TEC).

[0128] The at least one additive for reducing phenols may be a polyether, preferably a polyol. As used herein, the term “polyol” denotes a polyether with multiple hydroxyl groups. Examples of polyether polyols include polyethylene oxide, polyethylene glycol (PEG), polypropylene glycol (PPG), polytetrahydrofuran, and polytetramethylene ether glycol (PTMEG).

[0129] In preferred embodiments, the at least one additive for reducing phenols is polyethylene glycol (PEG).

[0130] The at least one additive for reducing phenols may comprise a derivative of PEG, such as an ester of PEG oligomers (such as diethylene glycol diacetate, tri-methylene glycol diacetate, etc.).

[0131] The at least one additive for reducing phenols may comprise a copolymer of PEG and PPG.

[0132] Preferably, the at least one additive for reducing phenols is selected from the group consisting of triethyl citrate, polyethylene glycol, and combinations thereof.

[0133] The at least one additive for reducing phenols may be triacetin.

[0134] The at least one additive for reducing phenol may comprise an acetylated or a short-chain or medium-chain fatty acid plasticiser. For example, the at least one additive for reducing phenol may comprise an acetylated monoglyceride, a diester of isosorbide (such as isosorbide diacetate, isosorbide butyrate, etc.).

[0135] Preferably, the additive coating comprises at least 5 percent by weight of the at least one additive for reducing phenols, more preferably at least 6 percent by weight of the at least one additive for reducing phenols, more preferably at least 8 percent by weight of the at least one additive for reducing phenols, more preferably at least 10 percent by weight of the at least one additive for reducing phenols, on a dry weight basis.

[0136] Preferably, the additive coating comprises up to 20 percent by weight of the at least one additive for reducing phenols, more preferably up to 18 percent by weight of the at least one additive for reducing phenols, more preferably up to 15 percent the at least one additive for reducing phenols, more preferably up to 12 percent the at least one additive for reducing phenols, on a dry weight basis.

[0137] For example, the additive coating may comprise between 5 percent by weight and 20 percent by weight of the at least one additive for reducing phenols, or between 6 percent by weight and 20 percent by weight of the at least one additive for reducing phenols, or between 8 percent by weight and 20 percent by weight of the at least one additive for reducing phenols, or between 10 percent by weight and 20 percent by weight of the at least one additive for reducing phenols, or between 5 percent by weight and 18 percent by weight of the at least one additive for reducing phenols, or between 6 percent by weight and 18 percent by weight of the at least one additive for reducing phenols, or between 8 percent by weight and 18 percent by weight of the at least one additive for reducing phenols, or between 10 percent by weight and 18 percent by weight of the at least one additive for reducing phenols, or between 5 percent by weight and 15 percent by weight of the at least one additive for reducing phenols, or between 6 percent by weight and 15 percent by weight of the at least one additive for reducing phenols, or between 8 percent by weight and 15 percent by weight of the at least one additive for reducing phenols, or between 10 percent by weight and 15 percent by weight of the at least one additive for reducing phenols, or between 5 percent by weight and 12 percent by weight of the at least one additive for reducing phenols, or between 6 percent by weight and 12 percent by weight of the at least one additive for reducing phenols, or between 8 percent by weight and 12 percent by weight of the at least one additive for reducing phenols, or between 10 percent by weight and 12 percent by weight of the at least one additive for reducing phenols, on a dry weight basis.

[0138] By applying one such additive to the processed paper material of the downstream element, the downstream element is made capable of capturing or otherwise converting at least some of the phenols produced by the aerosol-generating article. The inclusion of the at least one additive for reducing phenols in the cellulosic filtration material therefore helps reduce the level of phenols in the mainstream aerosol as it passes through the downstream plug element from the aerosol-generating substrate whilst minimising any undesirable effects on the taste sensation experience by the consumer.

[0139] In aerosol-generating articles according to the invention an overall content of the at least one additive for reducing phenols in the plug element on a dry weight basis is at least 0.5 percent by weight, preferably at least 1 percent by weight, more preferably at least 1 .5 percent by weight, even more preferably at least 2 percent by weight.

[0140] In some embodiments, an overall content of the at least one additive for reducing phenols in the plug element on a dry weight basis is at least 3 percent by weight, preferably at least 4 percent by weight, more preferably at least 5 percent by weight. An overall content of the at least one additive for reducing phenols in the plug element on a dry weight basis may be up to 15 percent by weight. Preferably an overall content of the at least one additive for reducing phenols in the plug element on a dry weight basis is up to 12 percent by weight, more preferably up to 10 percent by weight.

[0141] For example, an overall content of the at least one additive for reducing phenols in the plug element on a dry weight basis is from 0.5 percent by weight to 15 percent by weight, preferably from 1 percent by weight to 15 percent by weight, more preferably from 1 .5 percent by weight to 15 percent by weight, even more preferably from 2 percent by weight to 15 percent by weight. In some embodiments, an overall content of the at least one additive for reducing phenols in the plug element on a dry weight basis is from 3 percent by weight to 15 percent by weight, preferably from 4 percent by weight to 15 percent by weight, more preferably from 5 percent by weight to 15 percent by weight.

[0142] For example, an overall content of the at least one additive for reducing phenols in the plug element on a dry weight basis is from 0.5 percent by weight to 12 percent by weight, preferably from 1 percent by weight to 12 percent by weight, more preferably from 1.5 percent by weight to 12 percent by weight, even more preferably from 2 percent by weight to 12 percent by weight. In some embodiments, an overall content of the at least one additive for reducing phenols in the plug element on a dry weight basis is from 3 percent by weight to 12 percent by weight, preferably from 4 percent by weight to 12 percent by weight, more preferably from 5 percent by weight to 12 percent by weight.

[0143] For example, an overall content of the at least one additive for reducing phenols in the plug element on a dry weight basis is from 0.5 percent by weight to 10 percent by weight, preferably from 1 percent by weight to 10 percent by weight, more preferably from 1.5 percent by weight to 10 percent by weight, even more preferably from 2 percent by weight to 10 percent by weight. In some embodiments, an overall content of the at least one additive for reducing phenols in the plug element on a dry weight basis is from 3 percent by weight to 10 percent by weight, preferably from 4 percent by weight to 10 percent by weight, more preferably from 5 percent by weight to 10 percent by weight.

[0144] The plug element may comprise at least 1 percent by weight of the additive coating. Preferably, the plug element comprises at least 2 percent by weight of the additive coating, more preferably at least 3 percent by weight of the additive coating, more preferably at least 4 percent by weight of the additive coating, more preferably at least 5 percent by weight of the additive coating, on a dry weight basis.

[0145] The plug element may comprise up to 15 percent by weight of the additive coating, preferably up to 12 percent by weight of the additive coating, more preferably up to 10 percent by weight of the additive coating, on a dry weight basis. The additive coating comprises at least one additive for reducing phenols. That is, the additive coating comprises at least one additive which is capable of capturing or otherwise converting at least some of the phenols and phenol derivatives produced upon heating or burning of the aerosol-generating substrate. Preferably, the additive coating comprises at least one additive for reducing other undesirable compounds from the mainstream aerosol, such as carbon monoxide and formaldehyde.

[0146] Preferably, the additive coating is biodegradable such that the cellulosic filtration material including the combination of additive coating and paper material is biodegradable.

[0147] In some embodiments, the additive coating may comprise at least one exogenous polysaccharide.

[0148] The term “polysaccharide” generally identifies a polymeric carbohydrate composed of a long chain of monosaccharide units joined by glycosidic linkages with a general formula of (CeH Osjn, with n typically in the range from 40 to 3000. Polysaccharides, which occur widely in nature, exhibit a molecular structure that can be linear or highly branched, and may be composed by multiple ones of the same monosaccharide unit (homopolysaccharides) or include different monosaccharide units (heteropolysaccharides). Common examples of polysaccharides found in plants include cellulose and starch. Glycogen is an example of a polysaccharide commonly found in most mammalian and nonmammalian cells. Chitin is a polysaccharide found in the exoskeletons of insects, the cell walls of fungi, and certain hard structures in invertebrates and fish.

[0149] As used herein with reference to the present invention, the term “exogenous polysaccharide” is used to denote a polysaccharide incorporated into the additive coating that may be applied to a plug element comprising a paper material which has a certain endogenous polysaccharide content. As discussed above, the pulp from which paper materials are made comprises compounds, such as cellulose and hemicellulose, which are in and of themselves, polysaccharides or mixtures of polysaccharides. Thus, the term “exogenous polysaccharide” is used to denote a polysaccharide that is provided in an isolated form and has been extracted and separated from other components of the material (for example, a plant material) from which it has been derived. The exogenous polysaccharide is therefore provided extrinsically from any cellulose or hemicellulose derived from plant material that is present in the pulp from which the processed paper material is made. In other words, the term “exogenous polysaccharide” refers to a separate and distinct source of polysaccharide to any polysaccharide provided intrinsically within the processed paper material.

[0150] Following application of exogenous polysaccharide to the processed paper material of the plug element, an “overall polysaccharide content” in the plug element is understood to be the sum of a) the endogenous cellulose and hemicellulose content present in the plug element prior to application of exogenous polysaccharide, and b) the amount of exogenous polysaccharide applied to the paper material.

[0151] The additive coating may comprise at least 5 percent by weight of the at least one exogenous polysaccharide, on a dry weight basis. Preferably, the additive coating comprises at least 6 percent by weight of the at least one exogenous polysaccharide, more preferably at least

[0152] 8 percent by weight of exogenous polysaccharide, more preferably at least 10 percent by weight of the at least one exogenous polysaccharide, more preferably at least 12 percent by weight of the at least one exogenous polysaccharide, more preferably at least 15 percent by weight of the at least one exogenous polysaccharide, on a dry weight basis.

[0153] The additive coating preferably comprises up to 50 percent by weight of the at least one exogenous polysaccharide, more preferably up to 45 percent by weight of the at least one exogenous polysaccharide, more preferably up to 40 percent by weight of the at least one exogenous polysaccharide, more preferably up to 35 percent by weight of the at least one exogenous polysaccharide, even more preferably up to 30 percent by weight of the at least one exogenous polysaccharide, on a dry weight basis.

[0154] For example, the additive coating may comprise between 5 percent by weight and 50 percent by weight of the at least one exogenous polysaccharide, or between 6 percent by weight and 50 percent by weight of the at least one exogenous polysaccharide, or between 8 percent by weight and 50 percent by weight of the at least one exogenous polysaccharide, or between 10 percent by weight and 50 percent by weight of the at least one exogenous polysaccharide, or between 12 percent by weight and 50 percent by weight of the at least one exogenous polysaccharide, or between 15 percent by weight and 50 percent by weight of the at least one exogenous polysaccharide, or between 5 percent by weight and 45 percent by weight of the at least one exogenous polysaccharide, or between 6 percent by weight and 45 percent by weight of the at least one exogenous polysaccharide, or between 8 percent by weight and 45 percent by weight of the at least one exogenous polysaccharide, or between 10 percent by weight and 45 percent by weight of the at least one exogenous polysaccharide, or between 12 percent by weight and 45 percent by weight of the at least one exogenous polysaccharide, or between 15 percent by weight and 45 percent by weight of the at least one exogenous polysaccharide, or between 5 percent by weight and 40 percent by weight of the at least one exogenous polysaccharide, or between 6 percent by weight and 40 percent by weight of the at least one exogenous polysaccharide, or between 8 percent by weight and 40 percent by weight of the at least one exogenous polysaccharide, or between 10 percent by weight and 40 percent by weight of the at least one exogenous polysaccharide, or between 12 percent by weight and 40 percent by weight of the at least one exogenous polysaccharide, or between 15 percent by weight and 40 percent by weight of the at least one exogenous polysaccharide, or between 5 percent by weight and 35 percent by weight of the at least one exogenous polysaccharide, or between 6 percent by weight and 35 percent by weight of the at least one exogenous polysaccharide, or between 8 percent by weight and 35 percent by weight of the at least one exogenous polysaccharide, or between 10 percent by weight and 35 percent by weight of the at least one exogenous polysaccharide, or between 12 percent by weight and 35 percent by weight of the at least one exogenous polysaccharide, or between 15 percent by weight and 35 percent by weight of the at least one exogenous polysaccharide, or between 5 percent by weight and 30 percent by weight of the at least one exogenous polysaccharide, or between 6 percent by weight and 30 percent by weight of the at least one exogenous polysaccharide, or between 8 percent by weight and 30 percent by weight of the at least one exogenous polysaccharide, or between 10 percent by weight and 30 percent by weight of the at least one exogenous polysaccharide, or between 12 percent by weight and 30 percent by weight of the at least one exogenous polysaccharide, or between 15 percent by weight and 30 percent by weight of the at least one exogenous polysaccharide, on a dry weight basis.

[0155] The at least one exogenous polysaccharide provides numerous active functional groups, such as hydroxymethyl group, that are capable of scavenging from the smoke or aerosol certain gaseous compounds that may play a role in causing the dry and bitter sensation that has often been associated with conventional paper filters. These compounds may include, but are not limited to, weakly acidic compounds such as some aldehydes, as well as certain esters, ketones, alcohols, and pyrroles.

[0156] The inclusion of the at least one exogenous polysaccharide in the amounts described before therefore reduces the content of such compounds in the mainstream smoke or aerosol as it passes through the downstream plug element from the aerosol-generating substrate.

[0157] In aerosol-generating articles according to the invention an overall content of the at least one exogenous polysaccharide in the plug element on a dry weight basis may be at least 5 percent by weight, and is preferably at least 6 percent by weight, more preferably at least 7 percent by weight, even more preferably at least 8 percent by weight.

[0158] An overall content of the at least one exogenous polysaccharide in the plug element on a dry weight basis may be up to 20 percent by weight. Preferably an overall content of the at least one exogenous polysaccharide in the plug element on a dry weight basis is up to 18 percent by weight, more preferably up to 15 percent by weight, even more preferably up to 12 percent by weight. In some embodiments, an overall content of the at least one exogenous polysaccharide in the plug element on a dry weight basis is up to 10 percent by weight.

[0159] For example, an overall content of the at least one exogenous polysaccharide in the plug element on a dry weight basis is from 5 percent by weight to 20 percent by weight, preferably from 6 percent by weight to 20 percent by weight, more preferably from 7 percent by weight to 20 percent by weight, even more preferably from 8 percent by weight to 20 percent by weight.

[0160] For example, an overall content of the at least one exogenous polysaccharide in the plug element on a dry weight basis is from 5 percent by weight to 18 percent by weight, preferably from 6 percent by weight to 18 percent by weight, more preferably from 7 percent by weight to 18 percent by weight, even more preferably from 8 percent by weight to 18 percent by weight.

[0161] For example, an overall content of the at least one exogenous polysaccharide in the plug element on a dry weight basis is from 5 percent by weight to 15 percent by weight, preferably from 6 percent by weight to 15 percent by weight, more preferably from 7 percent by weight to 15 percent by weight, even more preferably from 8 percent by weight to 15 percent by weight.

[0162] For example, an overall content of the at least one exogenous polysaccharide in the plug element on a dry weight basis is from 5 percent by weight to 12 percent by weight, preferably from 6 percent by weight to 12 percent by weight, more preferably from 7 percent by weight to 12 percent by weight, even more preferably from 8 percent by weight to 12 percent by weight.

[0163] For example, an overall content of the at least one exogenous polysaccharide in the plug element on a dry weight basis is from 5 percent by weight to 10 percent by weight, preferably from 6 percent by weight to 10 percent by weight, more preferably from 7 percent by weight to 10 percent by weight, even more preferably from 8 percent by weight to 10 percent by weight.

[0164] The at least one exogenous polysaccharide is preferably selected from the group consisting of starch, modified starch, alkenyl succinate starches, pullulan, alginate, and combinations thereof. Suitable types of starch include, but are not limited to, potato starch and corn starch.

[0165] The term “starch” is used herein with reference to the present invention to denote a polymeric carbohydrate consisting of multiple glucose units joined by a-(1 -^4)-D glycosidic bonds. In nature, starch is produced in most green plants for energy storage purposes.

[0166] From a chemical viewpoint, starch consists primarily of two types of molecules: amylose and amylopectin. Amylose is characterised by a linear, helical structure, whereas amylopectin is highly branched. Different types of starch typically contain different proportions of amylose and amylopectin. For example, potato starch and corn starch contain amylopectin and amylose in an approximately 3:1 ratio, whereas waxy maize starch is almost entirely formed of amylose.

[0167] In some embodiments, the at least one exogenous polysaccharide is a modified starch, such as oxidized waxy potato starch or an acetylated starch.

[0168] Acetylated starch is a form of modified starch, which has been modified to increase the number of acetyl groups. As a result of the increased number of acetyl groups, the use of acetylated starch may improve the capabilities of starch in reducing phenols from the mainstream aerosol. Without wishing to be bound by theory, the introduction of acetyl groups is understood to also have an impact on wettability of the paper material. In fact, the esterification reaction that occurs between the acetyl groups and at least some hydroxyl groups in the cellulose molecules induces a change in the nature of at least some of the cellulose fibres from hydrophilic to hydrophobic. Thus, the paper material to which an additive coating comprising acetylated starch has been applied may have a reduced tendency to absorb moisture from the smoke or aerosol flowing through the plug element. This is desirable in that it may counter the effect, which has been observed with some conventional cellulose acetate filters and is often referred to as ‘dry smoke’, whereby the smoke or aerosol delivered to the consumer has a significantly reduced moisture content and may, therefore, under certain conditions, be perceived as undesirably dry. Further, increasing the contact angle of the paper material contact angle, such as for example increasing the contact angle of the paper material to greater than 90 degrees, preferably to greater than 105 degrees, may advantageously reduce the ability of the paper material to scavenge nicotine from the smoke or aerosol.

[0169] Methods for forming a sheet material, such as a sheet of processed paper material, into a rod-shaped plug element will be generally known to the skilled person, and may involve gathering or winding of the sheet material.

[0170] In aerosol-generating articles according to the present invention, the downstream element preferably comprises a plug element of the cellulosic filtration material described above circumscribed by a wrapper, for example a paper wrapper.

[0171] For example, a continuous web of processed paper material may be drawn and passed between pairs of superimposed embossing or crimping rolls.

[0172] In some embodiments, an additive coating has been applied to the continuous web of processed paper material prior to it being embossed or crimped or otherwise textured.

[0173] The additive coating may be applied to the processed paper material in any suitable manner. Preferably, the additive coating is applied to the processed paper material prior to the processed paper material being formed into the plug element.

[0174] Thus, the present disclosure further relates to a method for the production of a cellulosic filtration material for forming a plug element of an aerosol-generating article according to the invention, as described above. The method comprises the steps of: providing processed paper material; forming an additive coating solution comprising at least an additive for reducing phenols; applying the additive coating solution to the processed paper material; drying and optionally curing the coated processed paper material; and forming a plug element comprising the coated processed paper material.

[0175] The additive coating solution is formed by combining the dry ingredients of the additive coating and dispersing or dissolving them in water. The dry ingredients may include at least one additive for reducing phenols. The additive coating solution may optionally be heated prior to application of the solution to the processed paper material, for example, in order to bring about any necessary reactions between the components of the additive coating.

[0176] For example, in the step of applying the additive coating solution to the processed paper material, the additive coating solution may be applied to the processed paper material (typically in sheet form) by known printing processes, such as gravure printing or flexographic printing, or by known coating processes, like curtain coating, reverse gravure, semi-flexo, rod-coating, blade coating, comma coating, slot die coating. These processes may advantageously enable the formation of a defined layer of additive coating on at least part of an external surface of one or both sides of the processed paper material.

[0177] The additive coating solution may also be applied to the web of paper material prior to the web of paper material being supercalendered, for example by an impregnation process, such as by dipping the web of paper material into a bath of the additive coating or by spraying the additive coating solution onto the web of paper material, and letting the additive coating solution be at least partly absorbed into the web of paper material. Depending on how hydrophilic or hydrophobic the web of paper material is, the additive coating solution may permeate more or less deeply into the web of paper material or form more or less of a deposit of the additive coating on the external surface of at least one side of the web of paper material.

[0178] The web of paper material may subsequently be subjected to supercalendering to form a modified processed paper material that comprises the at least one additive within its volume.

[0179] As an alternative, in the step of applying the additive coating solution to the paper material, the additive coating solution may be applied to the processed paper material by injecting the additive coating solution into the plug element after the processed paper material has been processed and formed into a rod shape, or by dipping the formed plug element into a bath of the additive coating solution.

[0180] After the additive coating has been applied to the processed paper material, the thus treated processed paper material is preferably dried by any suitable means, including conventional heating, or microwave heating. Any curing of the additive coating may also be carried out during this drying step.

[0181] The step of drying the coated processed paper material, which may optionally comprise a curing of the coated processed paper material, may comprise heating the coated processed paper material using a conventional heater. Alternatively or in addition, the step of drying and optionally curing the coated processed paper material may comprise heating the coated processed paper material by microwave heating. The drying and optional curing of the additive coating solution is carried out in order to evaporate the water from the solution and to bring about curing of the additive coating or hardening of the additive coating or both. A paper wrapper may be wound about the gathered sheet of processed paper material in the forming cone, and overlapping edges of the paper wrapper may be bound together by applying an adhesive to a first edge of the wrapper and thereafter folding the other edge into contact with the first edge. The overlapping edges of the paper wrapper may be bound together by a heated roller, which both removes liquid and sets the adhesive. The resulting rod may be cut into segments having a predetermined length by a rotary cutter.

[0182] The wrapper circumscribing the cellulosic filtration material may have a basis weight of at least 50 grams per square metre (gsm). Where the downstream element is positioned at the downstream end of the aerosol-generating article, this may help to provide a desired firmness for the aerosol-generating article. In certain embodiments, it may be desirable to use a stiff wrapper, for example, a wrapper 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.

[0183] Preferably, the downstream element comprising the cellulosic filtration material has an average radial hardness of at least 75 percent, more preferably at least 80 percent, more preferably at least 85 percent. Preferably, the downstream element has a radial hardness of less than 100 percent, more preferably less than 95 percent. This can provide an aerosol-generating article having a downstream end with a satisfactory hardness for the consumer.

[0184] As used herein, the term “radial hardness” refers to resistance to compression is a direction transverse to a longitudinal axis. Radial hardness of an aerosol-generating article around a filter may be determined by applying a load across the article at the location of the filter, transverse to the longitudinal axis of the article, and measuring the average (mean) depressed diameters of the articles. Radial hardness is given by:

[0185] Radial hardness (%) 100 % where Ds is the original (undepressed) diameter, and Dd is the depressed diameter after applying a set load for a set duration. The harder the material, the closer the hardness is to 100%.

[0186] To determine the hardness of a portion (such as a filter) of an aerosol-generating article, aerosol-generating articles should be aligned parallel in a plane and the same portion of each aerosol-generating article to be tested should be subjected to a set load for a set duration. This test is performed using a known DD60A Densimeter device (manufactured and made commercially available by Heinr. Borgwaldt GmbH, Germany), which is fitted with a measuring head for aerosol-generating articles, such as cigarettes, and with an aerosol-generating article receptacle. For the standard operating procedure for such an apparatus, an overall load of 2 kg is applied for a duration of 20 seconds. After 20 seconds have elapsed (and with the load still being applied to the smoking articles), the depression in the load applying cylindrical rods is determined, and then used to calculate the hardness from the above equation. The temperature is kept in the region of 22 degrees Centigrade ± 2 degrees. The test described above is referred to as the DD60A Test. The standard way to measure the filter hardness is when the aerosol-generating articles have not been consumed. Additional information regarding measurement of average radial hardness can be found in, for example, U.S. Published Patent Application Publication Number 2016 / 0128378.

[0187] As described above, the downstream element comprising the cellulosic filtration material advantageously provides improved biodegradability compared to conventional cellulose acetate segments. Preferably, the downstream element is substantially free from cellulose acetate.

[0188] As described briefly above, the downstream element comprising the plug element is provided downstream of the aerosol-generating substrate and in axial alignment with the aerosolgenerating substrate.

[0189] In some embodiments, the aerosol-generating article is formed essentially of an aerosolgenerating substrate and of a downstream element as described above provided in abutting arrangement with the rod of aerosol-generating substrate. For example, the aerosol-generating substrate may be in the form of a cylindrical rod of shredded tobacco material circumscribed by a wrapper, and the downstream element may be attached to the wrapped rod by a band of tipping paper so as to form a mouthpiece of the aerosol-generating article.

[0190] In other embodiments, the aerosol-generating article comprises one or more additional elements also provided downstream of the aerosol-generating substrate and in axial alignment with the aerosol-generating substrate. The downstream element comprising the plug element and any further element provided downstream of the aerosol-generating substrate and in axial alignment with the aerosol-generating substrate form a downstream section of the aerosolgenerating article.

[0191] In some preferred embodiments, the downstream element comprising the plug element is a mouthpiece element.

[0192] The aerosol-generating article may comprise a mouthpiece at the downstream end or mouth end or proximal end of the aerosol-generating article, the mouthpiece consisting of the plug element alone.

[0193] Alternatively, the aerosol-generating article may comprise a mouthpiece at the downstream end or mouth end or proximal end of the aerosol-generating article, the mouthpiece including the plug element and one or more further elements axially aligned in an abutting end to end relationship with each other. The plug element and the one or more further elements may be formed of the same material. Alternatively, the one or more further elements may be formed of a material other than the material of the plug element.

[0194] Parameters or characteristics described herein in relation to the plug element used as the sole component of the mouthpiece may equally be applied to a plug element used as one of multiple components of the mouthpiece.

[0195] Advantageously, aerosol-generating articles according to the present invention wherein the downstream element is a mouthpiece element provide an acceptable visual impact and tactile experience for the consumer, thanks to the density and firmness of the plug element. Additionally, in aerosol-generating articles according to the present invention wherein the downstream element is a mouthpiece element, the cellulosic filtration material is capable of efficiently cooling a smoke or aerosol generated from the substrate, with little to no impact on the taste perceived by the consumer during use of the aerosol-generating article. As such, aerosol-generating articles according to the present invention wherein the plug element is a mouthpiece element provide a much more sustainable alternative to aerosol-generating articles comprising a cellulose acetate filter segment as a mouthpiece filter segment.

[0196] The mouthpiece element may have a low particulate phase filtration efficiency or even substantially no particulate phase filtration efficiency. Whilst capable of preventing substrate material from the aerosol-generating substrate potentially reaching the mouth of the consumer during use, a mouthpiece element having low particulate phase filtration efficiency has a reduced impact on delivery of aerosol species to the consumer. This is especially advantageous in aerosol-generating article wherein the aerosol-generating substrate is heated as opposed to being combusted.

[0197] In preferred embodiments, the particulate phase filtration efficiency of the plug element is less than about 30 percent, more preferably less than about 20 percent.

[0198] In some embodiments, the mouthpiece element 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. In such embodiments, the mouthpiece element may have an RTD of at least about 10 millimetres H2O.

[0199] The mouthpiece element 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.

[0200] Preferably, the mouthpiece element has a substantially circular cross-section.

[0201] Preferably, the mouthpiece element has an external diameter that is substantially the same as the external diameter of the aerosol-generating article.

[0202] A length of the mouthpiece may be at least about 3 millimetres, or at least about 5 millimetres. The length of the mouthpiece element may be less than or equal to about 11 millimetres, or less than or equal to about 9 millimetres.

[0203] The length of the mouthpiece element may be between about 3 millimetres and about 11 millimetres, or between about 3 millimetres and about 9 millimetres.

[0204] The length of the mouthpiece element may be between about 5 millimetres and about 11 millimetres, or between about 5 millimetres and about 9 millimetres.

[0205] For example, the length of the mouthpiece element may be about 7 millimetres.

[0206] The length of the mouthpiece element may be selected based on a desired total length of the aerosol-generating article.

[0207] The mouthpiece element may be circumscribed by a plug wrap.

[0208] The mouthpiece element may be unventilated such that air does not enter the aerosolgenerating article along the mouthpiece element.

[0209] The mouthpiece element may be connected to one or more adjacent components of the aerosol-generating article by means of a tipping wrapper.

[0210] The aerosol-generating article may define a mouth end cavity at the downstream end of the aerosol-generating article. For example, the mouthpiece element may itself be in the form of a hollow tubular element. As an alternative, the mouthpiece may include a non-hollow plug element as described above immediately upstream of a hollow tubular segment provided at the downstream end of the mouthpiece. As a further alternative, the mouth end cavity may be defined by an outer wrapper of the mouthpiece extending beyond a downstream end of a plug element as described above.

[0211] In some embodiments, the plug element may be an additional element provided downstream of the aerosol-generating substrate other than a mouthpiece element. That is, the aerosol-generating article comprises a mouthpiece and the plug element is provided between the aerosol-generating substrate and a mouthpiece of the aerosol-generating article.

[0212] For example, the downstream element may be a support element provided immediately downstream of the aerosol-generating substrate, preferably adjacent to the aerosol-generating substrate. One such support element is adapted to impart structural strength to the aerosolgenerating article. The support element is advantageously configured to resist downstream movement of the aerosol-generating substrate during insertion of the heating element of the aerosol-generating device into the aerosol-generating.

[0213] In some preferred embodiments, the downstream element comprising the plug element may form part of an aerosol-cooling element provided downstream of the aerosol-generating substrate, the aerosol-cooling element being adapted to facilitate cooling of the aerosol generated during use of the aerosol-generating article prior to reaching the downstream end of the aerosolgenerating article. As will become apparent from the following description of various features of an aerosolcooling element of an aerosol-generating article, the properties of the processed paper materials described herein make them particularly suitable for the manufacture of such an aerosolgenerating element. In particular, the low porosity and comparatively high density

[0214] The aerosol-cooling element preferably has a low resistance to draw. That is, the aerosolcooling element preferably offers a low resistance to the passage of air through the aerosolgenerating article. Preferably, the aerosol-cooling element does not substantially affect the resistance to draw of the aerosol-generating article.

[0215] 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.

[0216] It is desirable that the aerosol-cooling element has a high total surface area. Thus, in preferred embodiments, the aerosol-cooling element is formed by a sheet of processed paper material that has been crimped and then pleated, gathered, or folded to form the channels. The more folds or pleats within a given volume of the element then the higher the total surface area of the aerosol-cooling element. In a particularly preferred embodiment, the aerosol-cooling element is formed by a sheet of glassine paper that has been crimped and then pleated, gathered, or folded to form the channels.

[0217] In some preferred embodiments, the aerosol-cooling element may be formed from a processed paper material sheet having a thickness of between 5 micrometres and 500 micrometres, for example between 10 micrometres and 250 micrometres.

[0218] In some embodiments, the aerosol-cooling element has a total surface area of between 300 square millimetres per millimetre of length and 1000 square millimetres per millimetre of length. In other words, for every millimetre of length in the longitudinal direction the aerosolcooling element has between 300 square millimetres and 1000 square millimetres of surface area. Preferably, a total surface area of the aerosol-cooling element is around 500 square millimetres per millimetre of length.

[0219] For example, the aerosol-cooling element may be formed from a gathered sheet of processed paper material having a specific surface area of between 10 square millimetres per milligram and 100 square millimetres per milligram. In some embodiments, the aerosol-cooling element may be formed from a gathered sheet of processed paper material having a specific surface area of around 35 square mm per milligram. The specific surface area of the aerosol-cooling element can be conveniently determined as the plug element is formed from a processed paper material sheet having known width and thickness. For example, the processed paper material may be in the form of a sheet having an average thickness of 50 micrometres with a variation of ± 2 micrometres. Where the material also has a known width, for example, between 200 millimetres and 250 millimetres, the specific surface area and density can be conveniently calculated.

[0220] Preferably, the aerosol-cooling element has a porosity of between 50 percent and 90 percent in the longitudinal direction.

[0221] When an aerosol that contains a proportion of water vapour is drawn through the aerosolcooling element, some of the water vapour may condense on surfaces of the longitudinally extending channels defined through the aerosol-cooling element. If water condenses, it is preferred that droplets of the condensed water are maintained in droplet form on a surface of the aerosol-cooling element rather than being absorbed into the material forming the aerosol-cooling element. As a result of the supercalendering process from which it is obtained, a sheet of processed paper material exhibits advantageously low porosity and tendency to absorb water, and so in aerosol-generating articles according to the invention wherein the downstream element is an aerosol-cooling element, if some of the water vapour in the smoke or aerosol condenses when flowing through the downstream element, the droplets of condensed water remain primarily on a surface of the aerosol-cooling element.

[0222] The aerosol-cooling element may act to cool the temperature of a stream of smoke or aerosol drawn through the element by means of thermal transfer. Components of the smoke or aerosol will interact with the aerosol-cooling element and lose thermal energy.

[0223] The aerosol-cooling element may act to lower the perceived temperature of a stream of smoke or aerosol drawn through the element by causing condensation of components such as water vapour from the aerosol stream. Due to condensation, the smoke or aerosol stream may be drier after passing through the aerosol-cooling element. In some embodiments, the water vapour content of a stream of smoke or aerosol drawn through the aerosol-cooling element may be lowered by between about 20% and about 90%. The user may perceive the temperature of this smoke or aerosol to be lower than a moister smoke or aerosol of the same actual temperature. Thus, the feeling of the smoke or aerosol in a user’s mouth may be closer to the feeling provided by the smoke stream of a conventional cigarette.

[0224] In some embodiments, the temperature of a stream of smoke or aerosol may be lowered by more than 10 degrees Celsius as it is drawn through an aerosol-cooling element. In some embodiments, the temperature of a stream of smoke or aerosol may be lowered by more than 15 degrees Celsius or more than 20 degrees Celsius as it is drawn through an aerosol-cooling element. In some embodiments, the aerosol-cooling element removes a proportion of the water vapour content of a smoke or aerosol drawn through the element. In some embodiments, a proportion of other volatile substances may be removed from the aerosol stream as the smoke or aerosol is drawn through the aerosol-cooling element. For example, in some embodiments a proportion of phenolic compounds may be removed from the stream of smoke or aerosol as the smoke or aerosol is drawn through the aerosol-cooling element.

[0225] In some embodiments, 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.

[0226] 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.

[0227] 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.

[0228] 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.

[0229] 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.

[0230] The total length of the hollow tubular element may be selected based on a desired total length of the aerosol-generating article.

[0231] 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 aerosolgenerating substrate may be achieved by providing a ventilation zone at a location along a mouthpiece of the aerosol-generating article.

[0232] 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 aerosolgenerating element via the ventilation zone may have an advantageous effect on the nucleation and growth of aerosol particles.

[0233] 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.

[0234] 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.

[0235] 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 aerosolgenerating substrate. The upstream section preferably comprises an upstream element located immediately upstream of the rod of aerosol-generating substrate.

[0236] 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.

[0237] 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 aerosolgenerating substrate.

[0238] In preferred embodiments, the upstream element may comprise a plug element comprising a cellulosic filtration material comprising processed paper material. For example, the upstream element may be formed of the same cellulosic filtration material as the downstream element described above. From an environmental perspective, this is advantageous in that a greater portion of the aerosol-generating article as a whole is more readily degradable. Additionally, from a manufacturing viewpoint, it is advantageous to form different components of a same aerosol-generating article of the same material, as it will generally require less adjustments to the settings of existing apparatus.

[0239] 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.

[0240] 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.

[0241] 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.

[0242] 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.

[0243] The aerosol-generating article may be a combustible smoking article. A combustible smoking article typically comprises a cylindrical rod of tobacco cut filler surrounded by a paper wrapper and a cylindrical filter axially aligned, most often in an abutting end-to-end relationship, with the wrapped tobacco rod. The cylindrical filter typically comprises one or more plug elements of a fibrous filtration material circumscribed by a paper plug wrap. The wrapped tobacco rod and the filter are typically joined by a band of tipping wrapper, that circumscribes the entire length of the filter and an adjacent portion of the wrapped tobacco rod. In combustible smoking articles according to the present invention, the cylindrical filter comprises a downstream element comprising a plug element having the characteristics described above.

[0244] The aerosol-generating article may be an aerosol-generating article for generating an aerosol upon heating (a heated aerosol-generating article). A heated aerosol-generating article typically comprises a cylindrical rod of aerosol-generating substrate surrounded by a paper wrapper and a downstream section downstream of the rod of aerosol-generating substrate. The downstream section typically comprises at least one hollow tubular element immediately downstream of the rod of aerosol-generating substrate and a mouthpiece.

[0245] 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.

[0246] Preferably, the aerosol-generating article has a substantially circular cross-section.

[0247] 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.

[0248] 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.

[0249] 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.

[0250] 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.

[0251] 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.

[0252] 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 aerosol-generating 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.

[0253] Preferably, the rod of aerosol-generating substrate has an external diameter that is approximately equal to the external diameter of the aerosol-generating article.

[0254] 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.

[0255] 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.

[0256] 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.

[0257] 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.

[0258] 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.

[0259] 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, aerosolgenerating films and gel compositions.

[0260] 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.

[0261] 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.

[0262] 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 aerosol-generating 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.

[0263] 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 aerosol-generating 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 aerosol-generating 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.

[0264] 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.

[0265] 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.

[0266] 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.

[0267] 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.

[0268] 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.

[0269] In other preferred embodiments, the aerosol-generating substrate comprises homogenised plant material, preferably a homogenised tobacco material.

[0270] 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.

[0271] The homogenised plant material can be provided in any suitable form.

[0272] 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.

[0273] The homogenised plant material may be in the form of a plurality of pellets or granules.

[0274] 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.

[0275] 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.

[0276] 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.

[0277] 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.

[0278] 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.

[0279] 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.

[0280] Suitable aerosol-generating films for use as the aerosol-generating substrate of aerosolgenerating 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.

[0281] The aerosol-generating film may be a substantially tobacco-free aerosol-generating film.

[0282] 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.

[0283] The preferred weight ranges for nicotine in the gel composition are the same as those defined above in relation to aerosol-generating films.

[0284] Suitable gel compositions for use as the aerosol-generating substrate of aerosol-generating articles according to the invention are described in WO-A-2021 / 170642.

[0285] 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.

[0286] 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.

[0287] As used herein with reference to the present invention, the term “susceptor element” refers to a material that can convert electromagnetic energy into heat.

[0288] 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.

[0289] Preferably, the rod of aerosol-generating substrate is circumscribed by a wrapper. The wrapper may be a paper wrapper or a non-paper wrapper.

[0290] 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.

[0291] According to a second aspect of the present invention, there is provided an aerosolgenerating system comprising: an aerosol-generating article according to the first aspect of the invention; and an aerosol-generating device configured to heat the aerosol-generating substrate of the aerosol-generating article.

[0292] The aerosol-generating device comprises means for heating the aerosol-generating substrate 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.

[0293] The aerosol-generating device may be a handheld aerosol-generating device.

[0294] 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.

[0295] 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.

[0296] 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.

[0297] 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 aerosolgenerating 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.

[0298] 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 aerosolgenerating article.

[0299] Examples will now be further described with reference to the drawings of the accompanying Figures in which:

[0300] Figure 1 shows a schematic side sectional view of an aerosol-generating article in accordance with an embodiment of the invention; Figure 2 shows a schematic side sectional view of another aerosol-generating article in accordance with another embodiment of the invention;

[0301] Figure 3 shows a schematic side sectional view of another aerosol-generating article in accordance with a further embodiment of the invention; and

[0302] Figure 4 shows a schematic side sectional view of another aerosol-generating article in accordance with yet another embodiment of the invention.

[0303] The aerosol-generating article 1000 shown in Figure 1 comprises an aerosol-generating element 1002 in the form of a substantially cylindrical rod 1004 of shredded tobacco circumscribed by a wrapper 1006. Further, the aerosol-generating article 1000 comprises a substantially cylindrical mouthpiece 1008 comprising a segment 1010 of a cellulosic filtration material circumscribed by a plug wrap 1012.

[0304] The mouthpiece 1008 is attached to the aerosol-generating element 1002 by a band 1014 of tipping paper. Perforations 1016 formed through the tipping paper and the plug wrap are provided to enable admission of ventilation air into the segment 1010 when the consumer draws upon the mouthpiece 1008 during use. The aerosol-generating article 1000 has a length of 70 millimetres and an external diameter of 7.6 millimetres.

[0305] The segment 1010 is in the form of a plug element comprising glassine paper.

[0306] The aerosol-generating article 10 shown in Figure 2 comprises a rod 12 of aerosolgenerating substrate 12 and a downstream section 14 at a location downstream of the rod 12 of aerosol-generating substrate. Further, the aerosol-generating article 10 comprises an upstream section 16 at a location upstream of the rod 12 of aerosol-generating substrate. Thus, the aerosolgenerating article 10 extends from an upstream or distal end 18 to a downstream or mouth end 20, and has an overall length of about 45 millimetres.

[0307] The downstream section 14 comprises a support element 22 located immediately downstream of the rod 12 of aerosol-generating substrate, the support element 22 being in longitudinal alignment with the rod 12. In the embodiment of Figure 2, the upstream end of the support element 18 abuts the downstream end of the rod 12 of aerosol-generating substrate. In addition, the downstream section 14 comprises an aerosol-cooling element 24 located immediately downstream of the support element 22, the aerosol-cooling element 24 being in longitudinal alignment with the rod 12 and the support element 22. In the embodiment of Figure 1 , the upstream end of the aerosol-cooling element 24 abuts the downstream end of the support element 22. In the embodiment of Figure 2, the support element 22 and the aerosol-cooling element 24 together define an intermediate hollow section 50 of the aerosol-generating article 10.

[0308] The support element 22 comprises a first hollow tubular segment 26. The first hollow tubular segment 26 is provided in the form of a hollow cylindrical tube made of filtration material. The first hollow tubular segment 26 defines an internal cavity 28 that extends all the way from an upstream end 30 of the first hollow tubular segment to an downstream end 32 of the first hollow tubular segment 20. The internal cavity 28 is substantially empty, and so substantially unrestricted airflow is enabled along the internal cavity 28.

[0309] The first hollow tubular segment 26 has a length of about 8 millimetres, an external diameter of about 7.25 millimetres, and an internal diameter of about 1.9 millimetres. Thus, a thickness of a peripheral wall of the first hollow tubular segment 26 is about 2.67 millimetres.

[0310] The aerosol-cooling element 24 comprises a second hollow tubular segment 34. The second hollow tubular segment 34 is provided in the form of a hollow cylindrical tube made of filtration material. The second hollow tubular segment 34 defines an internal cavity 36 that extends all the way from an upstream end 38 of the second hollow tubular segment to a downstream end 40 of the second hollow tubular segment 34. The internal cavity 36 is substantially empty, and so substantially unrestricted airflow is enabled along the internal cavity 36.

[0311] The second hollow tubular segment 34 has a length of about 8 millimetres, an external diameter of about 7.25 millimetres, and an internal diameter of about 3.25 millimetres. Thus, a thickness of a peripheral wall of the second hollow tubular segment 34 is about 2 millimetres. Thus, a ratio between the internal diameter of the first hollow tubular segment 26 and the internal diameter of the second hollow tubular segment 34 is about 0.75.

[0312] The aerosol-generating article 10 comprises a ventilation zone 60 provided at a location along the second hollow tubular segment 34. In more detail, the ventilation zone is provided at about 2 millimetres from the upstream end of the second hollow tubular segment 34. A ventilation level of the aerosol-generating article 10 is about 25 percent.

[0313] In the embodiment of Figure 2, the downstream section 14 further comprises a mouthpiece element 42 at a location downstream of the intermediate hollow section 50. In more detail, the mouthpiece element 42 is positioned immediately downstream of the aerosol-cooling element 24. As shown in the drawing of Figure 2, an upstream end of the mouthpiece element 42 abuts the downstream end 40 of the aerosol-cooling element 18.

[0314] The mouthpiece element 42 is provided in the form of a cylindrical plug element 44 comprising glassine paper.

[0315] The mouthpiece element 42 has a length of about 12 millimetres and an external diameter of about 7.25 millimetres.

[0316] The rod 12 comprises an aerosol-generating substrate of one of the types described above.

[0317] The rod 12 of aerosol-generating substrate has an external diameter of about 7.25 millimetres and a length of about 12 millimetres.

[0318] The aerosol-generating article 10 further comprises an elongate susceptor 46 within the rod 12 of aerosol-generating substrate. In more detail, the susceptor 46 is arranged substantially longitudinally within the aerosol-generating substrate, such as to be approximately parallel to the longitudinal direction of the rod 12. As shown in the drawing of Figure 2, the susceptor 46 is positioned in a radially central position within the rod and extends effectively along the longitudinal axis of the rod 12. In more detail, the susceptor 46 is in thermal contact with the aerosolgenerating substrate. The susceptor 46 extends all the way from an upstream end to a downstream end of the rod 12. In effect, the susceptor 46 has substantially the same length as the rod 12 of aerosol-generating substrate.

[0319] In more detail, in the embodiment of Figure 2, the susceptor 46 is provided in the form of a strip and has a length of about 12 millimetres, a thickness of about 60 micrometres, and a width of about 4 millimetres.

[0320] The upstream section 16 comprises an upstream element 48 located immediately upstream of the rod 12 of aerosol-generating substrate, the upstream element 48 being in longitudinal alignment with the rod 12. In the embodiment of Figure 2, the downstream end of the upstream element 48 abuts the upstream end of the rod 12 of aerosol-generating substrate. This advantageously prevents the susceptor 46 from being dislodged. Further, this ensures that the consumer cannot accidentally contact the heated susceptor 46 after use.

[0321] The upstream element 48 comprises a segment of material 50 in the form of a cylindrical plug of filtration material and a first wrapper 52 circumscribing the segment of material 50. The segment of material 50 has a length of about 5 millimetres. The RTD of the segment of material 50 is about 30 millimetres H2O.

[0322] The aerosol-generating article 10 further comprises a combining wrapper 54 which attaches the upstream element 48 to the remaining components of the aerosol-generating article. In the embodiment of Figure 2 a single combining wrapper 54 is depicted, which circumscribes and holds together the upstream element 48, the rod 12, and the downstream section 14 to form the aerosol-generating article.

[0323] However, it will be clear that alternative configurations are possible, wherein two or more combining wrappers are employed to assemble the different components of the aerosolgenerating article. For example, a first combining wrapper could be used to attach the support element 22 to the aerosol-cooling element 24, and the resulting assembly could then be attached by means of a second combining wrapper to the upstream section 16 and the rod 12. The resulting combination of components could then be attached to the mouthpiece element 42 by means of a tipping wrapper. As shown in the drawing of Figure 1 , the aerosol-generating article 10 further comprises a wrapper 70 circumscribing the rod 12 of aerosol-generating substrate. The wrapper 70 is separate and distinct from the first wrapper 52 circumscribing the segment of material 50. Neither one of the first wrapper 52 and the wrapper 70 comprises a metallic foil. In the aerosol-generating article 10 of Figure 2, one or more of the first hollow tubular segment 26 of the support element 22, the second hollow tubular segment 34 of the aerosolcooling element 24, and the segment of material 50 of the upstream element 48 may be made of the same material according to the present invention used in the mouthpiece element 42.

[0324] The aerosol-generating article 100 shown in Figure 3 comprises a rod of aerosol-generating substrate 112 and a downstream section 114 at a location downstream of the rod 112 of aerosolgenerating substrate. Additionally, the aerosol-generating article 100 comprises an upstream section 116. Thus, the aerosol-generating article 100 extends from an upstream or distal end 118 - which substantially coincides with an upstream end of the upstream section 116 - to a downstream or mouth end 120, which coincides with a downstream end of the downstream section 114. The downstream section 114 comprises a hollow tubular element 122 and a mouthpiece element 150. The upstream section 116 comprises an upstream plug element 124.

[0325] The aerosol-generating article 10 has an overall length of about 45 millimetres and an outer diameter of about 7.2 mm.

[0326] The rod of aerosol-generating substrate 112 comprises a shredded tobacco material. The rod of aerosol-generating substrate 112 comprises 150 milligrams of a shredded tobacco material comprising from 13 percent by weight to 16 percent by weight of glycerine. The density of the aerosol-generating substrate is about 300 mg per cubic centimetre. The RTD of the rod of aerosol-generating substrate 112 is between about 6 to 8 mm H2O. The rod of aerosol-generating substrate 112 is individually wrapped by a plug wrap (not shown).

[0327] The hollow tubular element 122 is located immediately downstream of the rod 112 of aerosol-generating substrate, the hollow tubular element 122 being in longitudinal alignment with the rod 112. The upstream end of the hollow tubular element 122 abuts the downstream end of the rod 112 of aerosol-generating substrate.

[0328] The hollow tubular element 122 defines a hollow section of the aerosol-generating article 110. The hollow tubular element 122 does not substantially contribute to the overall RTD of the aerosol-generating article. In more detail, an RTD of the hollow tubular element 122 is about 0 mm H2O.

[0329] As shown in Figure 3, the hollow tubular element 122 is provided in the form of a hollow cylindrical tube made of cardboard. The hollow tubular element 122 defines an internal cavity that extends all the way from an upstream end of the hollow tubular element 122 to a downstream end of the hollow tubular element 122. The internal cavity is substantially empty, and so substantially unrestricted airflow is enabled along the internal cavity.

[0330] The hollow tubular element 122 has a length of about 21 millimetres, an external diameter of about 7.2 millimetres, and an internal diameter of about 6.7 millimetres. Thus, a thickness of a peripheral wall of the hollow tubular element 122 is about 0.25 millimetres. The aerosol-generating article 100 comprises a ventilation zone 160 provided at a location along the hollow tubular element 122. The ventilation zone 160 comprises a circumferential row of openings or perforations circumscribing the hollow tubular element 122. The perforations of the ventilation zone 160 extend through the wall of the hollow tubular element 122, in order to allow fluid ingress into the internal cavity from the exterior of the article 100. A ventilation level of the aerosol-generating article 10 is about 16 percent.

[0331] On top of a rod 112 of aerosol-generating substrate and a downstream section 14 at a location downstream of the rod 12, the aerosol-generating article 100 comprises an upstream section 140 at a location upstream of the rod 112. As such, the aerosol-generating article 10 extends from a distal end 116 substantially coinciding with an upstream end of the upstream section 140 to a mouth end or downstream end 118 substantially coinciding with a downstream end of the downstream section 114.

[0332] As described briefly above, the upstream section 116 comprises an upstream plug element 124 located immediately upstream of the rod 112 of aerosol-generating substrate, the upstream plug element 124 being in longitudinal alignment with the rod 112. The downstream end of the upstream plug element 124 abuts the upstream end of the rod 112 of aerosol-generating substrate. The upstream plug element 124 is provided in the form of a hollow cylindrical plug of filtration material having a wall thickness of about 1 mm and defining an upstream internal cavity. The upstream element 124 has a length of about 5 millimetres. An external diameter of the upstream plug element 124 is about 7.1 mm. An internal diameter of the upstream plug element 42 is about 5.1 mm.

[0333] The mouthpiece element 150 extends from the downstream end of the hollow tubular element 122 to the downstream or mouth end of the aerosol-generating article 100. The mouthpiece element 150 has a length of about 7 mm. An external diameter of the mouthpiece element 150 is about 7.2 mm.

[0334] The mouthpiece element 150 is provided in the form of a cylindrical plug element comprising glassine paper.

[0335] In the aerosol-generating article 100 of Figure 3, the plug element 124 of the upstream section 116 may be made of the same material according to the present invention used in the mouthpiece element 150.

[0336] The aerosol-generating article 510 shown in Figure 4 comprises a rod 512 of aerosolgenerating substrate and a downstream section 514 at a location downstream of the rod 512 of aerosol-generating substrate. Thus, the aerosol-generating article 10 extends from an upstream or distal end 518 to a downstream or mouth end 520, and has an overall length of about 45 millimetres. The downstream section 514 comprises a support element 522 located immediately downstream of the rod 512 of aerosol-generating substrate, the support element 522 being in longitudinal alignment with the rod 512. In the embodiment of Figure 4, an upstream end of the support element 522 abuts the downstream end of the rod 512 of aerosol-generating substrate. In addition, the downstream section 514 comprises an aerosol-cooling element 524 located immediately downstream of the support element 522, the aerosol-cooling element 524 being in longitudinal alignment with the rod 512 and the support element 522. In the embodiment of Figure 4, the upstream end of the aerosol-cooling element 524 abuts the downstream end of the support element 522. The downstream section 514 further comprises a mouthpiece filter 550 located immediately downstream of the aerosol-cooling element 524, the mouthpiece filter 550 being in longitudinal alignment with the rod 512, the support element 522 and the aerosol-cooling element 524. In the embodiment of Figure 4, the upstream end of the mouthpiece filter 550 abuts the downstream end of the aerosol-cooling element 524.

[0337] The support element 522 comprises a hollow tubular segment 526. The hollow tubular segment 526 is provided in the form of a hollow cylindrical tube made of filtration material. The hollow tubular segment 526 defines an internal cavity 528 that extends all the way from an upstream end of the first hollow tubular segment to a downstream end of the hollow tubular segment 520. The internal cavity 528 is substantially empty, and so substantially unrestricted airflow is enabled along the internal cavity 528.

[0338] The hollow tubular segment 526 has a length of about 8 millimetres, an external diameter of about 7.25 millimetres, and an internal diameter of about 1.9 millimetres. Thus, a thickness of a peripheral wall of the hollow tubular segment 526 is about 2.67 millimetres.

[0339] The aerosol-cooling element 524 is formed from a sheet 534 of glassine paper having a thickness of 50 micrometres ± 2 micrometres. The sheet 534 of glassine paper has been crimped and gathered to define a plurality of channels that extend along the length of the aerosol-cooling element 524. The total surface area of the aerosol-cooling element 524 is between 8000 square millimetres and 9000 square millimetres, which is equivalent to approximately 500 square millimetres per millimetre of length of the aerosol-cooling element 524. The specific surface area of the aerosol-cooling element 524 is approximately 2.5 square millimetres / milligram. A porosity of the aerosol-cooling element 524 in the longitudinal direction is between 60 percent and 90 percent. The crimped and gathered sheet 534 of glassine paper is wrapped within a filter paper wrapper 536 to form the aerosol-cooling element 524. The filter paper wrapper 536 may be made of glassine paper.

[0340] The mouthpiece filter 550 has a length of about 45 millimetres.

[0341] The rod 512, the support element 522, the aerosol-cooling element 524 and the mouthpiece 550 are assembled by being tightly wrapped within a paper wrapper 570. The interference between the paper wrapper 570 and each of the elements described above locates the elements and defines the structure of the aerosol-generating article 10.

[0342] Example A

[0343] An aerosol-generating article is prepared that comprises an aerosol-cooling element formed from a sheet of glassine paper having the characteristics described above with reference to the embodiment illustrated in Figure 4.

[0344] Comparative Example

[0345] An aerosol-generating article is prepared that is substantially identical to the aerosolgenerating article of Example A, but which differs from the aerosol-generating article of Example A in that the aerosol-cooling element is formed from a sheet of PLA having the same width, length and thickness of the sheet of glassine paper of Example A.

[0346] Tests

[0347] The performance of the aerosol-cooling element of Example A is compared with the performance of the aerosol-cooling element of the Comparative Example by subjecting each aerosol-generating article to a smoking test and measuring a number of parameters, including: a temperature of the aerosol reaching the mouth end of the article during the smoking cycle; a water content of the aerosol reaching the mouth end of the article during the smoking cycle; a delivery level of relevant compounds (nicotine, acrylamide, phenol, triacetin, glycerine, propylene glycol).

[0348] Delivered amounts of relevant compounds measured at the mouth end of each aerosolgenerating article are shown in the Table above. Advantageously, deliveries of nicotine and glycerine are evidently not impacted by the replacement of PLA with glassine paper. Further, levels of phenol and acrylamide in the aerosol are comparable or even reduced when PLA is replaced with glassine paper. Thus, the sensory experience for the consumer is not expected to be altered as a result of said replacement.

[0349] Temperature measurements show that, with each aerosol-generating article tested, a temperature of the aerosol reaching the mouth end of the aerosol-generating article initially increases by a few degrees Celsius over the first 3 to 4 puffs and then decreases by about 1 degree Celsius over the remaining 6 to 7 puffs. However, a maximum temperature reached with the aerosol-generating article of Example A is about 38 degrees Celsius, whereas a maximum temperature reached with the aerosol-generating article of the Comparative Example is about 40 degrees Celsius. Thus, the aerosol-cooling element of Example A is even more effective than the aerosol-cooling element of the Comparative Example at lowering the temperature of the aerosol flowing through.

[0350] Water content measurements show that, with each aerosol-generating article tested, a water content of the aerosol reaching the mouth end of the aerosol-generating article increases slightly over the first 9 to 10 puffs before substantially reaching a plateau. With the aerosolcooling element of Example A the water content varies within a range from 1.7 mg to 2.0 mg, whereas with the aerosol-generating article of the Comparative Example the water content varies within a range from 1.65 mg to 1.9 mg, so it is apparent that the two aerosol-generating articles tested provide very similar performances from this viewpoint. This is desirable as, especially in tropical conditions, significantly higher water contents may be associated with an unpleasant excess of warmth experienced by the consumer.

[0351] For the purpose of the present description and of the appended claims, except where otherwise indicated, all numbers expressing amounts, quantities, percentages, and so forth, are to be understood as being modified in all instances by the term "about". Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein. In this context, therefore, a number A is understood as A ± 5% of A. Within this context, a number A may be considered to include numerical values that are within general standard error for the measurement of the property that the number A modifies. The number A, in some instances as used in the appended claims, may deviate by the percentages enumerated above provided that the amount by which A deviates does not materially affect the basic and novel characteristic(s) of the claimed invention. Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein.

Claims

CLAIMS1 . An aerosol-generating article comprising: an aerosol-generating substrate; a downstream element provided downstream of the aerosol-generating substrate and in axial alignment with the aerosol-generating substrate, the downstream element comprising a plug element comprising a cellulosic filtration material comprising a processed paper material selected from the group consisting of glassine paper, parchment paper, and natural greaseproof paper, the cellulosic filtration material further comprising an additive coating applied to the processed paper material, the additive coating comprising at least 5 percent by weight of an additive for reducing phenols.

2. An aerosol-generating article according to claim 1 , wherein the processed paper material has a density of at least 0.85 grams / cubic centimetre.

3. An aerosol-generating article according to claim 1 , wherein the processed paper material has a density of at least 1 gram / cubic centimetre.

4. An aerosol-generating article according to any one of claims 1 to 3, wherein the processed paper material has a grammage of at least 40 gsm.

5. An aerosol-generating article according to any one of claims 1 to 4, wherein the processed paper material has a grammage of less than or equal to 60 gsm.

6. An aerosol-generating article according to any one of the preceding claims, wherein the processed paper material comprises one or more fillers, the one or more fillers preferably comprising calcium carbonate.

7. An aerosol-generating article according to claim 1 , wherein the additive for reducing phenols comprises one or more of an ester of a polycarboxylic acid, a polyether, an ester of polyethylene glycol oligomers, a copolymer of polyethylene glycol and polypropylene glycol (PPG).

8. An aerosol-generating article according to any one of the preceding claims, wherein the plug element is substantially free from cellulose acetate.

9. An aerosol-generating article according to any one of the preceding claims, wherein the processed paper material is glassine paper manufactured from highly refined kraft pulp or anthraquinone soda pulp.

10. An aerosol-generating article according to any one of claims 1 to 9, wherein the downstream element is a mouthpiece filter segment comprising the plug element and a filter wrapper circumscribing the plug element.

11. An aerosol-generating article according to any one of claims 1 to 9, wherein the downstream element is an aerosol-cooling element configured to cool an aerosol evolved from the aerosol-generating substrate upon heating.

12. An aerosol-generating article according to claim 11 , wherein the aerosol-cooling element comprises a plurality of longitudinally extending channels and has a porosity of between 50 percent and 90 percent in the longitudinal direction.

13. An aerosol-generating article according to claim 11 or 12, wherein the aerosol-cooling element has a total surface area of between 300 square millimetres per millimetre of length and 1000 square millimetres per millimetre of length.

14. An aerosol-generating article according to any one of claims 11 to 13, wherein the aerosolcooling element comprises a gathered sheet of the cellulosic filtration material.

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