WO2024256315A1

WO2024256315A1 - Aerosol-generating article with helical airflow path

Info

Publication number: WO2024256315A1
Application number: PCT/EP2024/065880
Authority: WO
Inventors: Matteo Bologna; Mirko MINZONI
Original assignee: Philip Morris Products SA
Current assignee: Philip Morris Products SA
Priority date: 2023-06-13
Filing date: 2024-06-10
Publication date: 2024-12-19
Anticipated expiration: 2025-12-13

Abstract

The invention relates to an aerosol-generating article (10) comprising a mouthpiece portion (12). The mouthpiece portion (12) comprises an extruded material (22). The extruded material (22) is airtight. The extruded material (22) has a cylindrical shape. A helical airflow path (24) is arranged in the extruded material that is fluidly connecting an upstream end face of the extruded material (22) with a downstream end face of the extruded material. The invention further relates to a method for extruding an extruded material of the aerosol-generating article and to an extrusion die (48).

Description

AEROSOL-GENERATING ARTICLE WITH HELICAL AIRFLOW PATH

The present invention relates to an aerosol-generating article, a method for extruding an extruded material of the aerosol-generating article and to an extrusion die.

It is known to provide an aerosol-generating article for generating an inhalable vapor. Such articles may comprise aerosol-forming substrate which is heated to a temperature at which one or more components of the aerosol-forming substrate are volatilised without burning the aerosol-forming substrate. Aerosol-forming substrate may be provided as part of a substrate portion of the aerosol-generating article. The aerosol-generating article may have a rod shape for insertion of the aerosol-generating article into a cavity, such as a heating chamber, of an aerosol-generating device. Due to the relatively low temperatures utilized for vaporizing the aerosol-forming substrate, it may not be necessary to provide a filter downstream of the substrate portion. However, it may be unpleasant for user to have a hollow portion downstream of the substrate portion. Further, it may be unpleasant for user to have lose aerosol-forming substrate potentially falling out of the downstream open end of the aerosol-forming article.

It would be desirable to have an aerosol-generating article without the need of a downstream filter. It would be desirable to have an aerosol-generating article preventing aerosol-forming substrate from falling out of the aerosol-generating article downstream of a substrate portion of the aerosol-generating article. It would be desirable to have an aerosolgenerating article preventing an unobstructed view of a substrate portion of the aerosolgenerating article.

According to an embodiment of the invention there is provided an aerosol-generating article that may comprise a mouthpiece portion. The mouthpiece portion may comprise an extruded material. The extruded material may be airtight. The extruded material may have a cylindrical shape. A helical airflow path may be arranged in the extruded material that may be fluidly connecting an upstream end face of the extruded material with a downstream end face of the extruded material.

According to an embodiment of the invention there is provided an aerosol-generating article comprising a mouthpiece portion. The mouthpiece portion comprises an extruded material. The extruded material is airtight. The extruded material has a cylindrical shape. A helical airflow path is arranged in the extruded material that is fluidly connecting an upstream end face of the extruded material with a downstream end face of the extruded material.

The extruded material may forgo the need of a downstream filter. Particularly, the extruded material may prevent lose residues of aerosol-forming substrate of the aerosolgenerating article from falling out of the mouthpiece portion. The extruded material may have a filtration effect sufficient to replace the downstream filter. This may be the case due to heat not burn aerosol-generating articles creating only a little amount of unwanted constituents that may be sufficiently filtered by the extruded material.

Additionally or alternatively, the extruded material may preventing an unobstructed view of a substrate portion of the aerosol-generating article. This may be desirable as a user may prefer a clean optic of the aerosol-generating article instead of directly viewing the aerosol-forming substrate when looking into the hollow mouthpiece portion.

The extruded material may have an outer diameter that corresponds to or may be slightly smaller than an outer diameter of the aerosol-generating article.

The extruded material may be arranged inside of the mouthpiece portion. The mouthpiece portion may be hollow. The mouthpiece portion may be tubular. The mouthpiece portion may have a hollow cylindrical shape. A sidewall of the mouthpiece portion may be made of cardboard. Apart from the extruded material, the mouthpiece portion may only comprise the cardboard sidewall. The extruded material may be arranged in, preferably may fill, the hollow cylindrical inner of the mouthpiece portion.

The extruded material may have an outer diameter that corresponds to or may be slightly smaller than an inner diameter of the mouthpiece portion of the aerosol-generating article.

The extruded material may form the mouthpiece portion. In this embodiment, the mouthpiece portion may not comprise a cardboard sidewall. In this embodiment, the mouthpiece portion preferably only comprises the extruded material.

The extruded material may prevent lateral airflow into the mouthpiece portion.

The helical airflow path may be arranged radially distanced from a circumference of the extruded material inside of the extruded material.

The extruded material may enable axial airflow through the mouthpiece portion by means of the helical airflow path.

The extruded material may be at least partly surrounded by a wrapping paper. The wrapping paper may be arranged in addition or alternatively to the cardboard sidewall. Preferably, the wrapping paper is arranged at least partly wrapped around the cardboard sidewall of the mouthpiece portion to connect the mouthpiece portion with the at least a further portion of the aerosol-generating article. Particularly preferred, the mouthpiece portion thus consists of the extruded material forming the inner of the mouthpiece portion and surrounded by the cardboard sidewall. The cardboard sidewall is particularly preferred at least partly wrapped by the wrapping paper to connect the mouthpiece portion with at least one other portion of the aerosol-generating article.

The extruded material may comprise at least two helical airflow paths. The at least two helical airflow paths are preferably arranged fluidly separate from each other within the extruded material. In other words, the helical airflow paths may be fluidly separate within the extruded material.

The extruded material may comprise between 2 to 16, preferably between 4 to 8, preferably 6, helical airflow paths that may be arranged in the extruded material and that may be fluidly connecting the upstream end face of the extruded material with the downstream end face of the extruded material.

The helical airflow paths may be arranged parallel to each other within the extruded material.

The helical airflow path may have a triangular cross-section.

Alternatively, the helical airflow path may have a drop-shaped, circular, rectangular or oval cross-section.

The aerosol-generating article may further comprise a substrate portion. The substrate portion may comprise aerosol-forming substrate. The substrate portion may be arranged upstream of the mouthpiece portion.

The substrate portion may directly abut the mouthpiece portion. Alternatively, a further portion such as a cooling portion may be arranged between the substrate portion and the mouthpiece portion. The wrapping paper described herein may be partly wrapped around the portion upstream of the mouthpiece portion to connect the mouthpiece portion with this upstream portion. Hence, the wrapping paper may connect the mouthpiece portion with the substrate portion or with the further portion.

The extruded material may be opaque. An opaque extruded material may enable a view of the aerosol-forming substrate of the substrate portion through the extruded material, if this is desired.

The radius of the helical airflow path may be at least 50% of the radius of the mouthpiece portion, preferably at least 60% of the radius of the mouthpiece portion, more preferably at least 70% of the radius of the mouthpiece portion, most preferably at least 80% of the radius of the mouthpiece portion.

The pitch of the helical airflow path may be between 0.3 and 3 of the length of the extruded material. The pitch of the helical airflow path may be between 0.6 and 2 of the length of the extruded material. The pitch of the helical airflow path may be around the length of the extruded material.

The length of the extruded material may be measured along or parallel to a longitudinal central axis of the aerosol-generating article. The length of the mouthpiece portion may be measured along or parallel to the longitudinal central axis of the aerosolgenerating article. The length of the extruded material may correspond to the length of the mouthpiece portion. In other words, the extruded material may have the same length as the mouthpiece portion. The longitudinal central axis of the aerosol-generating article may be the same as a longitudinal central axis of the extruded material. The longitudinal central axis of the aerosol-generating article may be the same as a longitudinal central axis of the mouthpiece portion.

The sidewall of the mouthpiece portion may be coaxially aligned with the extruded material. The wrapping paper may be coaxially aligned with one or both of the sidewall of the mouthpiece portion and the extruded material.

The helical airflow path may be arranged at the periphery of the extruded material. The term “at the periphery” may describe an arrangement of the helical airflow path near the periphery of the extruded material or, in other words, under and close to the circumferential surface of the extruded material. The arrangement is preferably such that lateral airflow into the extruded material is prevented in only axial airflow through the extruded material is enabled by the helical airflow path. The helical airflow path may be arranged closer towards the periphery of the extruded material than towards the central longitudinal axis of the extruded material.

This may be advantageous in aerosol-forming substrate particles experiencing a larger centrifugal force when traveling through the helical airflow path. This may lead to a more secure trapping or slowing of these particles while traveling through the extruded material.

Arranging the helical airflow path at the periphery of the extruded material may have the further advantage of the helical airflow path being closer to the periphery of the mouthpiece portion. In other words, arranging the helical airflow path at the periphery of the extruded material may reduce the distance between the helical airflow path and ambient air. This may lead to a more effective cooling of the air traveling through the helical airflow path. The cooling of the air flowing through the helical airflow path may lead to a condensation of the volatilized aerosol-forming substrate and the formation of an inhalable aerosol. This may forgo the need of providing a separate cooling portion of the aerosol-generating article or at least improve aerosol formation synergistically together with a separate cooling portion.

The helical airflow path may have a cross-sectional area of between 5% to 50% of the cross-sectional area of the extruded material.

The extruded material may comprise, preferably consists of, cellulose acetate, foamed acetate, foamed PLA polymeric compound or cellulose compound.

The extruded material may be made from one or both of biodegradable and recyclable material.

The extruded material may be non-porous. The extruded material may be fluid-tight. The extruded material may be airtight.

The helical airflow path through the extruded material may be the only way of air to flow through the extruded material. The helical airflow path may be configured as a groove in the extruded material.

The helical airflow path may be narrower towards a periphery of the helical airflow path. In other words, the cross-section of the helical airflow path may be narrower in a radial outwards direction.

This may have the advantage that aerosol-forming substrate particles from the upstream substrate portion of the aerosol-generating article may be caught more effectively in the helical airflow path. More specifically, particles of the aerosol-forming substrate being drawn through the helical airflow path may experience a centrifugal force and may thus be pushed against the radially outward portion of the helical airflow path during traveling through the helical airflow path. Constructing the helical airflow path with a narrow radially outward portion may more effectively trap these aerosol-forming substrate particles during them being drawn through the extruded material.

The helical airflow path may be wider towards a central longitudinal axis of the extruded material. In other words, the cross-section of the helical airflow path may be wider in a radial inwards direction.

The resistance to draw of the mouthpiece portion including the extruded material may be negligible due to the provisioning of the helical airflow path through the extruded material. At the same time, as described herein, the extruded material may prevent unwanted lose particles of the aerosol-forming substrate to be drawn through the mouthpiece portion. Further, as described herein, the extruded material may prevent an undesired unobstructed view of the aerosol-forming substrate through the hollow mouthpiece portion.

The invention further relates to a method for extruding an extruded material of an aerosol-generating article as described herein. The method may comprise: extruding a continuous rod of extruded material while rotating an extrusion die as described herein to create the helical airflow path.

The rotation of the extrusion die may create the helical airflow path in the extruded material.

The method may comprise the step of cooling of the extruded material.

The method may comprise the step of pulling of the extruded material.

The method may comprise the step of cutting of the extruded material.

The invention further relates to an extrusion die, preferably for a method as described herein. The extrusion die may comprise an extrusion opening and at least one solid triangular cylinder arranged in the extrusion opening.

The solid triangular cylinder may also be referred to as mandrel.

If the extrusion die is used in the method as described herein comprising a rotation of the extrusion die, the solid triangular cylinder may be straight as the helical airflow path may be created by means of the rotation of the extrusion die. The solid triangular cylinder may have a helical shape. This is particularly preferred if the extrusion takes place in a stationary extrusion die, in which case the helical airflow path is created by means of the helical shape of the solid triangular cylinder.

Particularly preferred, the solid triangular cylinder has a helical shape and is used in a method as described herein in which the extrusion die is rotated. In this case, the helical airflow path is created by a synergistic combination of rotating the extrusion die and providing the solid triangular cylinder with a helical shape. The combination of the rotation of the extrusion die and the helical shape of the solid triangular cylinder then creates the helical airflow path within the extruded material.

Generally, if a different cross-sectional shape of the helical airflow path in the herein described triangular shape is desired, the solid triangular cylinder may instead be provided as a solid cylinder having a different cross-sectional shape. For example, instead of a solid triangular cylinder, a solid cylinder having a drop-shaped, circular, rectangular or oval crosssection may be used.

For each individual helical airflow path, the extrusion die may comprise one correspondingly shaped solid cylinder.

The aerosol-generating article may be used in an aerosol-generating device. The aerosol-generating article may be inserted into a cavity of the aerosol-generating device. The aerosol-generating device may heat the aerosol-forming substrate of the aerosol-generating article thereby creating an inhalable aerosol.

As used herein, the terms ‘proximal’, ‘distal’, ‘downstream’ and ‘upstream’ are used to describe the relative positions of components, or portions of components, of the aerosolgenerating device in relation to the direction in which a user draws on the aerosol-generating device during use thereof.

The aerosol-generating device may comprise a mouth end through which in use an aerosol exits the aerosol-generating device and is delivered to a user. The mouth end may also be referred to as the proximal end. In use, a user draws on the proximal or mouth end of the aerosol-generating device in order to inhale an aerosol generated by the aerosolgenerating device. Alternatively, a user may directly draw on an aerosol-generating article inserted into an opening at the proximal end of the aerosol-generating device. The opening at the proximal end may be an opening of the cavity. The cavity may be configured to receive the aerosol-generating article. The aerosol-generating device comprises a distal end opposed to the proximal or mouth end. The proximal or mouth end of the aerosol-generating device may also be referred to as the downstream end and the distal end of the aerosolgenerating device may also be referred to as the upstream end. Components, or portions of components, of the aerosol-generating device may be described as being upstream or downstream of one another based on their relative positions between the proximal, downstream or mouth end and the distal or upstream end of the aerosol-generating device.

As used herein, an ‘aerosol-generating device’ relates to a device that interacts with an aerosol-forming substrate to generate an aerosol. The aerosol-forming substrate may be part of an aerosol-generating article, for example part of a smoking article. An aerosolgenerating device may be a smoking device that interacts with an aerosol-forming substrate of an aerosol-generating article to generate an aerosol that is directly inhalable into a user’s lungs thorough the user's mouth. An aerosol-generating device may be a holder. The device may be an electrically heated smoking device. The aerosol-generating device may comprise a housing, electric circuitry, a power supply, a heating chamber and a heating element.

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

The aerosol-generating device may comprise electric circuitry. The electric circuitry may comprise a microprocessor, which may be a programmable microprocessor. The microprocessor may be part of a controller. The electric circuitry may comprise further electronic components. The electric circuitry may be configured to regulate a supply of power to the heating element. Power may be supplied to the heating element continuously following activation of the aerosol-generating device or may be supplied intermittently, such as on a puff-by-puff basis. The power may be supplied to the heating element in the form of pulses of electrical current. The electric circuitry may be configured to monitor the electrical resistance of the heating element, and preferably to control the supply of power to the heating element dependent on the electrical resistance of the heating element.

The aerosol-generating device may comprise a power supply, typically a battery, within a main body of the aerosol-generating device. In one embodiment, the power supply is a Lithium-ion battery. Alternatively, the power supply may be a Nickel-metal hydride battery, a Nickel cadmium battery, or a Lithium based battery, for example a Lithium-Cobalt, a Lithium-lron-Phosphate, Lithium Titanate or a Lithium-Polymer battery. As an alternative, the power supply may be another form of charge storage device such as a capacitor. The power supply may require recharging and may have a capacity that enables to store enough energy for one or more usage experiences; for example, the power supply may have sufficient capacity to continuously generate aerosol for a period of around six minutes or for a period of a multiple of six minutes. In another example, the power supply may have sufficient capacity to provide a predetermined number of puffs or discrete activations of the heating element.

The cavity of the aerosol-generating device may have an open end into which the aerosol-generating article is inserted. The open end may be a proximal end. The cavity may have a closed end opposite the open end. The closed end may be the base of the cavity. The closed end may be closed except for the provision of air apertures arranged in the base. The base of the cavity may be flat. The base of the cavity may be circular. The base of the cavity may be arranged upstream of the cavity. The open end may be arranged downstream of the cavity. The cavity may have an elongate extension. The cavity may have a longitudinal central axis. A longitudinal direction may be the direction extending between the open and closed ends along the longitudinal central axis. The longitudinal central axis of the cavity may be parallel to the longitudinal axis of the aerosol-generating device.

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

An airflow channel may run through the cavity. Ambient air may be drawn into the aerosol-generating device, into the cavity and towards the user through the airflow channel. Downstream of the cavity, a mouthpiece may be arranged or a user may directly draw on the aerosol-generating article. The airflow channel may extend through the mouthpiece.

In any of the aspects of the disclosure, the heating element may comprise an electrically resistive material. Suitable electrically resistive materials include but are not limited to: semiconductors such as doped ceramics, electrically "conductive" ceramics (such as, for example, molybdenum disilicide), carbon, graphite, metals, metal alloys and composite materials made of a ceramic material and a metallic material. Such composite materials may comprise doped or undoped ceramics. Examples of suitable doped ceramics include doped silicon carbides. Examples of suitable metals include titanium, zirconium, tantalum platinum, gold and silver. Examples of suitable metal alloys include stainless steel, nickel-, cobalt-, chromium-, aluminium- titanium- zirconium-, hafnium-, niobium-, molybdenum-, tantalum-, tungsten-, tin-, gallium-, manganese-, gold- and iron- containing alloys, and super-alloys based on nickel, iron, cobalt, stainless steel, Timetai® and iron-manganese-aluminium based alloys. In composite materials, the electrically resistive material may optionally be embedded in, encapsulated or coated with an insulating material or vice-versa, depending on the kinetics of energy transfer and the external physicochemical properties required. As described, in any of the aspects of the disclosure, the heating element may be part of an aerosol-generating device. The aerosol-generating device may comprise an internal heating element or an external heating element, or both internal and external heating elements, where "internal" and "external" refer to the aerosol-forming substrate. An internal heating element may take any suitable form. For example, an internal heating element may take the form of a heating blade. Alternatively, the internal heater may take the form of a casing or substrate having different electro-conductive portions, or an electrically resistive metallic tube. Alternatively, the internal heating element may be one or more heating needles or rods that run through the center of the aerosolforming substrate. Other alternatives include a heating wire or filament, for example a Ni-Cr (Nickel-Chromium), platinum, tungsten or alloy wire or a heating plate. Optionally, the internal heating element may be deposited in or on a rigid carrier material. In one such embodiment, the electrically resistive heating element may be formed using a metal having a defined relationship between temperature and resistivity. In such an exemplary device, the metal may be formed as a track on a suitable insulating material, such as ceramic material, and then sandwiched in another insulating material, such as a glass. Heaters formed in this manner may be used to both heat and monitor the temperature of the heating elements during operation.

An external heating element may take any suitable form. For example, an external heating element may take the form of one or more flexible heating foils on a dielectric substrate, such as polyimide. The flexible heating foils can be shaped to conform to the perimeter of the substrate receiving cavity. Alternatively, an external heating element may take the form of a metallic grid or grids, a flexible printed circuit board, a molded interconnect device (MID), ceramic heater, flexible carbon fibre heater or may be formed using a coating technique, such as plasma vapour deposition, on a suitable shaped substrate. An external heating element may also be formed using a metal having a defined relationship between temperature and resistivity. In such an exemplary device, the metal may be formed as a track between two layers of suitable insulating materials. An external heating element formed in this manner may be used to both heat and monitor the temperature of the external heating element during operation.

As an alternative to an electrically resistive heating element, the heating element may be configured as an induction heating element. The induction heating element may comprise an induction coil and a susceptor. In general, a susceptor is a material that is capable of generating heat, when penetrated by an alternating magnetic field. When located in an alternating magnetic field. If the susceptor is conductive, then typically eddy currents are induced by the alternating magnetic field. If the susceptor is magnetic, then typically another effect that contributes to the heating is commonly referred to hysteresis losses. Hysteresis losses occur mainly due to the movement of the magnetic domain blocks within the susceptor, because the magnetic orientation of these will align with the magnetic induction field, which alternates. Another effect contributing to the hysteresis loss is when the magnetic domains will grow or shrink within the susceptor. Commonly all these changes in the susceptor that happen on a nano-scale or below are referred to as “hysteresis losses”, because they produce heat in the susceptor. Hence, if the susceptor is both magnetic and electrically conductive, both hysteresis losses and the generation of eddy currents will contribute to the heating of the susceptor. If the susceptor is magnetic, but not conductive, then hysteresis losses will be the only means by which the susceptor will heat, when penetrated by an alternating magnetic field. According to the invention, the susceptor may be electrically conductive or magnetic or both electrically conductive and magnetic. An alternating magnetic field generated by one or several induction coils heat the susceptor, which then transfers the heat to the aerosol-forming substrate, such that an aerosol is formed. The heat transfer may be mainly by conduction of heat. Such a transfer of heat is best, if the susceptor is in close thermal contact with the aerosol-forming substrate.

As used herein, the term ‘aerosol-generating article’ refers to an article comprising an aerosol-forming substrate that is capable of releasing volatile compounds that can form an aerosol. For example, an aerosol-generating article may be a smoking article that generates an aerosol that is directly inhalable into a user’s lungs through the user's mouth. An aerosolgenerating article may be disposable.

As used herein, the term ‘aerosol-forming substrate’ relates to a substrate capable of releasing one or more volatile compounds that can form an aerosol. Such volatile compounds may be released by heating the aerosol-forming substrate. An aerosol-forming substrate may conveniently be part of an aerosol-generating article or smoking article.

The aerosol-forming substrate may be a solid aerosol-forming substrate. The aerosolforming substrate may be arranged in the substrate portion. The aerosol-forming substrate may comprise both solid and liquid components. The aerosol-forming substrate may comprise a tobacco-containing material containing volatile tobacco flavour compounds which are released from the substrate upon heating. The aerosol-forming substrate may comprise a non-tobacco material. The aerosol-forming substrate may comprise an aerosol former that facilitates the formation of a dense and stable aerosol. Examples of suitable aerosol formers are glycerine and propylene glycol.

The aerosol-generating substrate preferably comprises homogenised tobacco material, an aerosol-former and water. Providing homogenised tobacco material may improve aerosol generation, the nicotine content and the flavour profile of the aerosol generated during heating of the aerosol-generating article. Specifically, the process of making homogenised tobacco involves grinding tobacco leaf, which more effectively enables the release of nicotine and flavours upon heating.

Below, there is provided a non-exhaustive list of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more features of another example, embodiment, or aspect described herein.

Example 1. An aerosol-generating article comprising a mouthpiece portion, wherein the mouthpiece portion comprises an extruded material, wherein the extruded material is airtight, wherein the extruded material has a cylindrical shape, wherein a helical airflow path is arranged in the extruded material that is fluidly connecting an upstream end face of the extruded material with a downstream end face of the extruded material.

Example 2. The aerosol-generating article according to example 1 , wherein the extruded material has an outer diameter that corresponds to or is slightly smaller than an outer diameter of the aerosol-generating article.

Example 3. The aerosol-generating article according to any of the preceding examples, wherein the extruded material is arranged inside of the mouthpiece portion.

Example 4. The aerosol-generating article according to any of the preceding examples, wherein the extruded material forms the mouthpiece portion.

Example 5. The aerosol-generating article according to any of the preceding examples, wherein the extruded material is at least partly surrounded by a wrapping paper.

Example 6. The aerosol-generating article according to any of the preceding examples, wherein the extruded material comprises between 2 to 16, preferably between 4 to 8, preferably 6, helical airflow paths that are arranged in the extruded material and that are fluidly connecting the upstream end face of the extruded material with the downstream end face of the extruded material.

Example 7. The aerosol-generating article according to example 6, wherein the helical airflow paths are fluidly separate within the extruded material.

Example 8. The aerosol-generating article according to example 6 or 7, wherein the helical airflow paths are parallel arranged within the extruded material.

Example 9. The aerosol-generating article according to any of the preceding examples, wherein the helical airflow path has a triangular cross-section.

Example 10. The aerosol-generating article according to any of the preceding examples, wherein the aerosol-generating article further comprises a substrate portion, wherein the substrate portion comprises aerosol-forming substrate, and wherein the substrate portion is arranged upstream of the mouthpiece portion. Example 11 . The aerosol-generating article according to any of the preceding examples, wherein the extruded material is opaque.

Example 12. The aerosol-generating article according to any of the preceding examples, wherein the radius of the helical airflow path is at least 50% of the radius of the mouthpiece portion, preferably at least 60% of the radius of the mouthpiece portion, more preferably at least 70% of the radius of the mouthpiece portion, most preferably at least 80% of the radius of the mouthpiece portion.

Example 13. The aerosol-generating article according to any of the preceding examples, wherein the helical airflow path is arranged at the periphery of the extruded material.

Example 14. The aerosol-generating article according to any of the preceding examples, wherein the helical airflow path has a cross-sectional area of between 5% to 50% of the cross-sectional area of the extruded material.

Example 15. The aerosol-generating article according to any of the preceding examples, wherein the extruded material comprises, preferably consists of, cellulose acetate, foamed acetate, foamed PLA polymeric compound or cellulose compound.

Example 16. The aerosol-generating article according to any of the preceding examples, wherein the extruded material is non-porous.

Example 17. The aerosol-generating article according to any of the preceding examples, wherein the helical airflow path is narrower towards a periphery of the helical airflow path.

Example 18. A Method for extruding an extruded material of an aerosol-generating article according to any of the preceding examples, wherein the method comprises:

- extruding a continuous rod of extruded material while rotating an extrusion die to create the helical airflow path.

Example 19. An extrusion die, preferably for a method according to example 18, wherein the extrusion die comprises an extrusion opening and at least one solid triangular cylinder arranged in the extrusion opening.

Example 20. The extrusion die of example 19, wherein the solid triangular cylinder has a helical shape.

Features described in relation to one embodiment may equally be applied to other embodiments of the invention.

The invention will be further described, by way of example only, with reference to the accompanying drawings in which: Fig. 1 shows a side view of an aerosol-generating article comprising a mouthpiece portion according to the present invention;

Fig. 2 shows a side view of an extruded material of the mouthpiece portion of the aerosol-generating article;

Fig. 3 shows a side view of a particle of aerosol-forming substrate being drawn through the extruded material;

Fig. 4 shows a top view of the particle of aerosol-forming substrate being drawn through the extruded material;

Figs. 5A and 5B show different cross-sectional shapes of the extruded material of the mouthpiece portion;

Fig. 6 shows a side view of an extrusion method of the present invention;

Fig. 7 shows an exploded view of an extrusion die of the present invention;

Fig. 8 shows a front view of the extrusion die;

Fig. 9 shows a sectional side view of the extrusion die; and

Fig. 10 shows a further embodiment of the extrusion die.

Figure 1 shows an aerosol-generating article 10. The aerosol-generating article 10 comprises a mouthpiece portion 12 according to the present invention. The aerosolgenerating article 10 further comprises an optional portion 14 such as a cooling portion, a substrate portion 16 comprising aerosol-forming substrate and a front plug.

The mouthpiece portion 12 comprises or is made of extruded material 22 as described with reference to Figures 2 to 5 below.

The optional portion 14 is preferably configured as a cooling portion. The optional portion 14 may be tubular. The optional portion 14 may comprise a sidewall of cardboard. The optional portion 14 may comprise perforations in the sidewall to enable ambient air to be drawn into the optional portion 14.

The substrate portion 16 comprises aerosol-forming substrate.

The front plug is a solid plug made of acetate tow to prevent aerosol-forming substrate from falling out of an upstream end of the aerosol-generating article 10.

Arrows in Figure 1 denote a direction in which air is drawn through the aerosolgenerating article 10. At a downstream direction 20, a user may inhale the generated aerosol. The user may place his or her lips directly around the periphery of the mouthpiece portion 12 to inhale the generated aerosol.

Figure 2 shows an extruded material 22 of the mouthpiece portion 12. The mouthpiece portion 12 may consist of the extruded material 22. Alternatively, the extruded material 22 may be arranged inside a sidewall of the mouthpiece portion 12. Such a sidewall of the mouthpiece portion 12 may be made of cardboard. Additionally, (not shown), a wrapping paper may be arranged for connecting the mouthpiece portion 12 with the optional portion 14 or the substrate portion 16. The wrapping paper may at least partly be wrapped around the mouthpiece portion 12. The wrapping paper may at least partly be wrapped around the optional portion 14 or the substrate portion 16. In addition or alternatively to a wrapping paper, a tipping paper may be arranged wrapping one or more of the portions of the aerosol-generating article 10 for attachment of these portions.

The extruded material 22 as shown in Figure 2 has a cylindrical shape. The extruded material 22 is airtight. The extruded material 22 comprises a helical airflow path 24. The helical airflow path 24 enables air to be drawn along or parallel to a longitudinal central axis 26 of the extruded material 22 through the extruded material 22. The longitudinal central axis 26 of the extruded material 22 is identical to a longitudinal central axis 26 of the mouthpiece portion 12 and a longitudinal central axis 26 of the aerosol-generating article 10.

The helical airflow path 24 has a triangular cross-section. The helical airflow path 24 gets narrower near the periphery of the helical airflow path 24. The helical airflow path 24 gets wider towards the central longitudinal axis of the extruded material 22. This, as described in more detail with reference to Figures 3 and 4 below, leads to an increased centrifugal force 28 acting upon lose particles of aerosol-forming substrate being drawn through the helical airflow path 24 and therefore a trapping of such particular of the aerosolforming substrate.

As shown in Figure 2, the pitch of the helical airflow path 24 is similar or identical to the length of the extruded material 22. The length of the extruded material 22 is measured along the longitudinal central axis 26 of the extruded material 22. The helical airflow path 24 has an air inlet at an upstream end face 30 of the extruded material 22. The helical airflow path 24 has an air outlet 32 at a downstream end face of the extruded material 22.

In Figure 2, an exemplary number of four individual helical airflow path 24s is shown. However, this number is only illustrative. The helical airflow path 24 may comprise a single helical airflow path 24 or up to 16 helical airflow path 24s with a particularly preferred number of six helical airflow path 24s.

Figure 3 shows an exemplary single lose air outlet 34 of aerosol-forming substrate being drawn through the helical airflow path 24 of the extruded material 22. Due to the helical shape of the helical airflow path 24, a centrifugal force 28 acts upon the single air outlet 34 so that the single air outlet 34 is pushed towards the periphery of the helical airflow path 24. Due to the narrowing shape of the helical airflow path 24 in a radial outwards direction (corresponding to the periphery of the helical airflow path 24), the lose air outlet 34 gets stuck in the narrow part of the helical airflow path 24. As a consequence, the air outlet 34 is filtered by the extruded material 22 and does not reach the air outlet 32. Figure 4 shows a top view of the filtering action of Figure 3. Figure 4 shows in more detail the centrifugal force 28 acting upon the lose air outlet 34 of the aerosol-forming substrate. Further, Figure 4 shows how the air outlet 34 is pushed further towards the narrow peripheral part of the helical airflow path 24 while traveling through the helical airflow path 24. Finally, the air outlet 34 gets stuck between the walls of the airflow path in the peripheral part of the airflow path. The triangular shape of the helical airflow path 24 aids the trapping of the air outlet 34 due to the air outlet 34 being stuck between the narrowing walls of the of the helical airflow path 24.

Figures 5A and 5B show examples of different cross-sectional shapes of the helical airflow path 24. Figure 5A shows a pentagonal cross-sectional shape of the helical airflow path 24. Figure 5B shows a drop-shaped cross-sectional shape of the helical airflow path 24. The different cross-sectional shapes of the helical airflow path 24 have in common that the helical airflow path 24 narrows towards the periphery of the helical airflow path 24 to enable trapping of particles of aerosol-forming substrate therein.

Figure 6 shows an extrusion machine 36 for extruding the extruded material 22. The extrusion machine 36 comprises an area where the raw material 38 is inserted into the extrusion machine 36. The material is subsequently processed by an extruder 40 and an exiting extrusion rod 42 of the material is pulled through a cooling unit 44 by means of a pulling system 46. The extruded material 22 may subsequently be cut into appropriate portions suitable for arrangement in or forming the mouthpiece portion 12.

Figure 7 shows a more detailed view of an extrusion die 48 used in a downstream area or downstream of the extruder 40. The direction of processing of the extruded material 22 is indicated by the arrows in Figure 7. The material exits an exit hole 50 arranged in an extruder exit plate 52 of the extruder 40. The material then enters a mandrel plate 54 via an aperture 56. The mandrel plate 54 comprises solid triangular cylinders 58 (also denoted as “mandrels”). The solid triangular cylinders 58 are straight. The mandrel plate 54 together with the solid triangular cylinders 58 is configured movable. In more detail, the mandrel plate 54 together with the solid triangular cylinder as can be rotated. The mandrel plate 54 together with the solid triangular cylinder is configured rotatable during the extrusion process so that the herein described helical airflow path 24 is created within the extruded material 22.

Downstream of the mandrel plate 54, a spacer 60 is provided. Downstream of the spacer 60, a die cap 62 comprising a die exit 64 is provided. Subsequently, the extruded material 22 is cooled, pulled by the pulling system 46 and cut into appropriately shaped portions.

Figure 8 shows a front view of the extrusion die 48. Particularly, the arrangement of the solid triangular cylinders 58 is depicted in Figure 8 such that the helical airflow path 24 is formed within the extruded material 22 and close to the periphery of the extruded material 22 as exemplarily shown in Figures 2 to 5.

Figure 9 shows a sectional side view along the lines A-A’ of Figure 8. Particularly, Figure 9 shows the assembled configuration of the extrusion die 48 as shown in the exploded view in Figure 7.

Figure 10 shows an alternative configuration of the mandrels. In the configuration of Figure 10, the mandrels are not configured as solid triangular cylinders 58 but, instead, as solid helical cylinders 66. The solid helical cylinders 66 have a helical shape. The helical shape of the solid helical cylinders 66 creates the helical airflow path 24 during the extrusion process without the need of a rotation of the mandrel plate 54 together with the solid cylinders. If beneficial, the mandrel plate 54 together with the solid helical cylinders 66 may still be rotated. However, the helical shape of the helical airflow path 24 may essentially be created due to the helical shape of the solid helical cylinders 66 inside of the rotational movement of the mandrel plate 54 together with the solid helical cylinders 66.

Claims

1. An aerosol-generating article comprising a mouthpiece portion, wherein the mouthpiece portion comprises an extruded material, wherein the extruded material is airtight, wherein the extruded material has a cylindrical shape, wherein a helical airflow path is arranged in the extruded material that is fluidly connecting an upstream end face of the extruded material with a downstream end face of the extruded material, wherein the helical airflow path is arranged at the periphery of the extruded material.

2. The aerosol-generating article according to claim 1 , wherein the extruded material has an outer diameter that corresponds to or is slightly smaller than an outer diameter of the aerosol-generating article.

3. The aerosol-generating article according to any of the preceding claims, wherein the extruded material is arranged inside of the mouthpiece portion.

4. The aerosol-generating article according to any of the preceding claims, wherein the extruded material forms the mouthpiece portion.

5. The aerosol-generating article according to any of the preceding claims, wherein the helical airflow path has a triangular cross-section.

6. The aerosol-generating article according to any of the preceding claims, wherein the aerosol-generating article further comprises a substrate portion, wherein the substrate portion comprises aerosol-forming substrate, and wherein the substrate portion is arranged upstream of the mouthpiece portion.

7. The aerosol-generating article according to any of the preceding claims, wherein the radius of the helical airflow path is at least 50% of the radius of the mouthpiece portion, preferably at least 60% of the radius of the mouthpiece portion, more preferably at least 70% of the radius of the mouthpiece portion, most preferably at least 80% of the radius of the mouthpiece portion.

8. The aerosol-generating article according to any of the preceding claims, wherein the helical airflow path has a cross-sectional area of between 5% to 50% of the cross-sectional area of the extruded material.

9. The aerosol-generating article according to any of the preceding claims, wherein the extruded material comprises, preferably consists of, cellulose acetate, foamed acetate, foamed PLA polymeric compound or cellulose compound.

10. The aerosol-generating article according to any of the preceding claims, wherein the extruded material is non-porous.

11 . The aerosol-generating article according to any of the preceding claims, wherein the helical airflow path is narrower towards a periphery of the helical airflow path.

12. A Method for extruding an extruded material of an aerosol-generating article according to any of the preceding claims, wherein the method comprises:

- extruding a continuous rod of extruded material while rotating an extrusion die comprising a solid triangular cylinder with a helical shape to create the helical airflow path.

13. An extrusion die, preferably for a method according to claim 12, wherein the extrusion die comprises an extrusion opening and at least one solid triangular cylinder arranged in the extrusion opening.

14. The extrusion die of claim 13, wherein the solid triangular cylinder has a helical shape.