WO2025162878A1

WO2025162878A1 - Cartridge with porous matrix for storing liquid aerosol-forming substrate

Info

Publication number: WO2025162878A1
Application number: PCT/EP2025/051988
Authority: WO
Inventors: Matteo Bologna; Sébastien CAPELLI; Bruno Christian Joseph CHASSOT; Yaobo DING; Srđan ISAJLOVIĆ; Alexandre REDONDO; Jerome Uthurry
Original assignee: Philip Morris Products SA
Current assignee: Philip Morris Products SA
Priority date: 2024-02-01
Filing date: 2025-01-27
Publication date: 2025-08-07
Anticipated expiration: 2026-08-01

Abstract

The invention relates to a cartridge (16) for an aerosol-generating device. The cartridge (16) comprises a cartridge housing having a cartridge inlet (34) and a cartridge outlet (36), and a cartridge chamber (64) extending between the cartridge inlet (34) and the cartridge outlet (36). The cartridge comprises a heating element (46) for heating an aerosol-forming substrate to form an aerosol, the heating element (46) extending into the cartridge chamber (64). The cartridge comprises a porous matrix (60) configured for retention of a liquid-based aerosol-forming substrate, the porous matrix (60) having a first major surface which is substantially flat, wherein at least a portion of the first major surface of the porous matrix (60) is in direct contact with the heating element (46). The invention also relates to an aerosol-generating system (10) comprising the cartridge (16) and an aerosol-generating device wherein the aerosol-generating device comprises a cavity (22) configured to receive the cartridge (16).

Description

CARTRIDGE WITH POROUS MATRIX FOR STORING LIQUID AEROSOL-FORMING SUBSTRATE

The present invention relates to a cartridge with a porous matrix for storing liquid aerosol-forming substrate. The cartridge is configured to be used with an aerosol-generating device. The invention also relates to an aerosol-generating system comprising the aerosolgenerating device and the cartridge.

It is known to provide an aerosol-generating device for generating an inhalable vapor. Such devices may heat aerosol-forming substrate to a temperature at which one or more components of the aerosol-forming substrate are volatilised without burning the aerosolforming substrate. Aerosol-forming substrate may be provided as part of a cartridge. The cartridge together with the aerosol-generating device may form an aerosol-generating system. The cartridge may be received in a cavity, such as a heating chamber, of the aerosolgenerating device. A heating element may be arranged in or around the heating chamber for heating the aerosol-forming substrate once the cartridge is inserted into the heating chamber of the aerosol-generating device. The aerosol-generating device may comprise a mouthpiece for closing the cavity once the cartridge has been inserted into the cavity.

Cartridges with heating elements extending within the internal volume of the cartridge may be limited in the materials applicable for use as an aerosol-forming substrate. In particular, such materials may be limited to substantially solid tobacco based or tobacco derived materials. This limitation of the types and formats of applicable aerosol-forming substrates restricts user choice and may increase production costs of the cartridges.

It would be desirable to have a cartridge for an aerosol-generating device which is more flexible with respect to materials applicable for use as an aerosol-forming substrate. It would further be desirable to have a cartridge for an aerosol-generating device which is more flexible with respect to materials applicable for use as flavourants.

It would further be desirable to have a cartridge that allows to reduce manufacturing costs.

According to an embodiment of the invention there may be provided a cartridge for an aerosol-generating device. The cartridge may comprise a cartridge housing having a cartridge inlet and a cartridge outlet, and a cartridge chamber extending between the cartridge inlet and the cartridge outlet. The cartridge may further comprise a heating element for heating an aerosol-forming substrate to form an aerosol, the heating element extending into the cartridge chamber. The cartridge may further comprise a porous matrix configured for retention of a liquid-based aerosol-forming substrate, the porous matrix may have a first major surface which is substantially flat, wherein at least a portion of the first major surface of the porous matrix may be in direct contact with the heating element. According to an embodiment of the invention there is provided a cartridge for an aerosol-generating device. The cartridge comprises a cartridge housing having a cartridge inlet and a cartridge outlet, and a cartridge chamber extending between the cartridge inlet and the cartridge outlet. The cartridge further comprises a heating element for heating an aerosolforming substrate to form an aerosol, the heating element extending into the cartridge chamber. The cartridge further comprises a porous matrix configured for retention of a liquidbased aerosol-forming substrate, the porous matrix having a first major surface which is substantially flat, wherein at least a portion of the first major surface of the porous matrix is in direct contact with the heating element.

Provision of a porous matrix for retention of a liquid-based aerosol-forming substrate allows the aerosol-forming substrate to be tailored to specific requirements. For example, transfer of thermal energy into the porous matrix, extraction of volatile compounds from the aerosol-forming substrate, resistance to draw of the porous matrix may be configured by selective choice of material and/or material properties of the porous matrix. Accordingly, cartridges for use with aerosol-generating devices, having different properties and/or configured to respond differently to similar heating conditions in a heating chamber of a device for generating an aerosol may be readily and easily provided. Provision of a first major surface which is substantially flat, provides an increased surface area to volume ratio relative to prior art articles, which are typically cylindrical. Accordingly, thermal energy may be transmitted more readily and efficiently into the porous matrix, in use, whilst volatile compounds may be extracted more readily therefrom, also. Cartridges according to the invention therefore provide highly customisable porous matrices with enhanced efficiency of thermal transfer thereinto and volatile compounds therefrom.

In some embodiments, the porous matrix may have or comprise a second major surface, for example which is substantially flat. The first and second major surfaces may be substantially parallel to one another, for example may extend in generally parallel relations. The first and second major surfaces may be spaced from one another by less than 5 mm, by less than 4 mm or by less than 3 mm. The porous matrix may have a generally parallelepiped shape. In embodiments, the porous matrix may comprise an upstream end and/or a downstream end. The porous matrix may be configured or arranged such that, in use, flow of fluid through the porous matrix travels from the upstream end to the downstream end. For a given volume, a parallelepiped shaped matrix has a comparably large surface area to volume ratio than for example a cylindrical matrix element. Additionally, for a given volume and length, a parallelepiped shaped matrix has a relatively larger cross-sectional area than for example a corresponding cylindrical element. The porous matrix may be a planar porous matrix. The porous matrix may have a cuboid shape.

The porous matrix may have a width, a length and/or a thickness, for example where the width, length and/or thickness are measured in a direction perpendicular to one another.

The thickness may comprise the distance between the first and second major surfaces, where provided. The thickness of the porous matrix may range between 1 millimeter and 10 millimeters. The thickness of the porous matrix may range between 3 millimeters and 7 millimeters.

The width of the porous matrix may range between 5 millimeters and 60 millimeters. The width of the porous matrix may range between 10 millimeters and 50 millimeters. The width of the porous matrix may range between 20 millimeters and 40 millimeters.

The length of the porous matrix may range between 10 millimeters and 80 millimeters. The length of the porous matrix may range between 20 millimeters and 70 millimeters. The length of the porous matrix may range between 30 millimeters and 60 millimeters.

A porous matrix refers to a material characterized by a network of interconnected voids or pores within its structure. This matrix is designed to facilitate the passage or storage of fluids or gases.

The matrix material may encompass natural materials, polymers, ceramics, metals, or composites, depending on the desired characteristics for a particular application.

The matrix material may encompass organic cotton, cotton, or cellulose based materials such as viscose regenerated films or membranes, foams, aerogels, sponge, and sheets. The matrix material may encompass non-woven materials. The matrix material may encompass carbon. The matrix material may encompass polymeric materials such as polyamide orpolytetrafluorethylene.

The matrix material may encompass inorganic materials as silica or ceramics such as aluminiumoxide (AI2O3), Zirconiumoxide (ZrO2), Siliconcarbide (SiC), Hydroxyapatite (Ca5(PO4)3(OH)), Magnesium-alumina silicate (2MgO-2AI2O3-5SiO2). The matrix material may encompass porous metal fibres such as stainless steel fibres, nickel fibres, titanium-nickel fibres, iron-chromium-aluminium fibres or metal foams, such as aluminium foam, nickel foam, iron foam, copper foam, titanium foam.

The porosity is typically introduced during the fabrication process through techniques such as foaming, sintering, or leaching. The resulting structure comprises a three-dimensional arrangement of pores, forming a continuous network throughout the material. The pores are designed to store and transport a liquid aerosol-forming substrate. The size, distribution, and geometry of the pores within the matrix play a crucial role in determining its performance. Pore size can range from nano- to macroscopic scales, influencing factors such as permeability, surface area, and mechanical strength. The interconnected nature of the pores promotes fluid transport within the matrix.

The porous matrix may have a pore size of between 10 micrometers to 500 micrometers, wherein the porous matrix has a pore size of between 20 micrometers to 250 micrometers, wherein the porous matrix has a pore size of between 30 micrometers to 150 micrometers.

The porous matrix may be constructed as a layer of porous matrix material. The porous matrix may be constructed from one or more layers of porous matrix material. The porous matrix may be constructed from 2 to 20 layers of porous matrix material. The porous matrix may be constructed from 2 to 10 layers of porous matrix material.

The porous matrix may be constructed from a plurality of layers of porous matrix material, and wherein the layers are made from at least two different porous matrix materials. The different porous matrix materials may have different material properties. For example, the porous matrix materials may differ in one or more of material properties selected from: temperature resistance, porosity and average pore size.

Layers of porous material that are closer to the heating element may be formed form a matrix material having a higher temperature resistance. In this way the overall temperature resistance of the porous matrix may be increased.

Layers of porous material that are further away from the heating element may be formed form a matrix material having a higher liquid retention ability. In this way the overall liquid retention capacity may be increased.

The porous matrix may be formed from a plurality of layers of porous matrix material, wherein the average pore size of the layers of porous matrix material decreases the closer the layer of porous matrix material is located to the heating element. With such configuration the porous matrix may promote transportation of liquid aerosol-forming substrate towards the resistive heating element through capillary action.

The porous matrix may be arranged in the cartridge chamber. The porous matrix may be arranged in the inner volume defined by the cartridge chamber. The porous matrix may occupy at least 80 percent of the inner volume defined by the cartridge chamber. The porous matrix may occupy at least 90 percent of the inner volume defined by cartridge chamber. The porous matrix may occupy at least 95 percent of the inner volume defined by cartridge chamber. The porous matrix may extend essentially over the total inner volume defined by the cartridge chamber.

The cartridge may define a longitudinal axis. The longitudinal axis of the cartridge may extend from the cartridge inlet to the cartridge outlet. The first major surface of the porous matrix may be arranged parallel to the longitudinal axis of the cartridge. The heating element may comprise one or more heating surfaces for heating an aerosol-generating substrate to form an aerosol.

The one or more heating surfaces may be planar heating surfaces. The one or more heating surfaces may comprise one or more planar heating surfaces for heating an aerosolgenerating substrate to form an aerosol.

At least a portion of the porous matrix comprising the aerosol-forming substrate within the chamber will be in direct contact with the one or more planar heater surfaces. Preferably, the porous matrix is configured to be in direct contact with the one or more planar heating surfaces over a total surface area that corresponds to at least 30 percent of the total cross- sectional area of the chamber in the plane in which the planar heating element extends.

For the purposes of the present invention, a porous matrix (or a portion thereof) is in ‘direct contact’ with the planar heating surface if the porous matrix is touching a portion of the planar heating surface that is heated during use, with no space or intervening material in between. As a result of this direct contact, heat can be transferred directly from the planar heating surface to the contacting portion of the porous matrix.

At least a portion of the first major surface of the porous matrix may be in direct contact with the heating surface of the heating element. At least a portion of the first major surface of the porous matrix may be in direct contact with one of the planar heating surfaces of the heating element.

The heating element may be in direct contact with the first major surface of the porous matrix over at least 30 percent of a total area of the first major surface of the porous matrix. The heating element may be in direct contact with the first major surface of the porous matrix over at least 60 percent of a total area of the first major surface of the porous matrix. The heating element may be in direct contact with the first major surface of the porous matrix over at least 90 percent of a total area of the first major surface of the porous matrix.

The heating surface and the first major surface of the porous matrix may be arranged parallel to the longitudinal axis of the cartridge, which longitudinal axis of the cartridge may extend from the cartridge inlet to the cartridge outlet.

The heating element may be configured as a resistive heating element. The heating element may comprise one or more heating tracks. The one or more heating tracks may be arranged in a wound, meandering, coiled, zigzag or spiral pattern. The one or more heating tracks may be arranged in a plane defining the planar heating surface of the heating element.

The heating element may be electrically connected to a pair of cartridge electrical contacts. The cartridge electrical contacts may be provided at an outer surface of the cartridge housing. When inserted into a cavity of an aerosol-generating device the cartridge electrical contacts are used to electrically connect the resistive heating element to a power source of the aerosol-generating device. In this way the resistive heating element may be supplied with electrical power to generate the required heat for volatilization of the aerosol-forming substrate.

Alternatively, the heating element may be configured as an inductive heating element. In case of being an inductive heating element, the heating element may comprise an induction coil. Potentially, the heating element may further comprise a susceptor element which may be heated by eddy currents induced by an alternating current running through the induction coil. The susceptor element in this case may be arranged inside of the induction coil. The susceptor element may be provided in the cartridge while the induction coil may be provided in the aerosol-generating device, particularly the main body of the aerosol-generating device. Alternatively, both the susceptor element as well as the induction coil may be provided in the cartridge. The susceptor may be shaped to form the one or more planar heating surfaces.

The operating temperature of the heating element may range between 200 degrees Celsius to 350 degrees Celsius. The operating temperature of the heating element may range between 220 degrees Celsius to 290 degrees Celsius. The operating temperature of the heating element may be adjusted to the type of aerosol-forming substrate that is used in the cartridge.

The cartridge housing may be formed from food contact rated plastic such as polycarbonate, ABS, liquid crystal polymer, copolyester plastic, from plant-based materials such as wood or bamboo and/or from high temperature plastics, such as liquid crystal polymer, polyetheretherketone, or cyclic olefin copolymer.

The cartridge housing may extend between the cartridge inlet and the cartridge outlet. The cartridge housing may define the cartridge chamber. The cartridge housing may define the cartridge chamber between the cartridge inlet and the cartridge outlet. The housing may be a rigid housing. The housing may be formed from a rigid material.

The cartridge chamber may be configured to conduct an airflow between the cartridge inlet and the cartridge outlet. The cartridge may be configured to conduct an airflow between the cartridge inlet and the cartridge outlet via the cartridge chamber. The cartridge may be configured to conduct an airflow through the cartridge chamber. The cartridge may be configured to conduct an airflow within the cartridge housing.

The airflow path through the cartridge may be parallel to a longitudinal axis of the cartridge. The airflow path through the cartridge may be parallel to the first major surface of the porous matrix. The airflow path through the cartridge may be parallel to the planar heating surface. The cartridge may be configured to conduct an airflow parallel to a longitudinal axis of the cartridge with the airflow extending between the cartridge inlet and the cartridge outlet via the cartridge chamber. The cartridge may comprise a first porous matrix and a second porous matrix. The first porous matrix may be configured for retention of a liquid-based aerosol-forming substrate. The second porous matrix may be configured for retention of a liquid-based aerosol-forming substrate. The first porous matrix may have a first major surface which is substantially flat. The second porous matrix may have a first major surface which is substantially flat. The first porous matrix may be planar. The second porous matrix may be planar. The heating element may be a planar heating element. The heating element may comprise a first planar heating surface and a second planar heating surface. At least a portion of the first major surface of the first porous matrix may be in direct contact with the first planar heating surface. At least a portion of the first major surface of the second porous matrix may be in direct contact with the second planar heating surface. The planar heating element may be sandwiched between the first porous matrix and the second porous matrix. The first major surface of the first porous matrix, the first major surface of the second porous matrix, the first planar heating surface and the second planar heating surface may be parallelly arranged to a longitudinal axis of the cartridge. The cartridge may be configured to conduct an airflow parallel to a longitudinal axis of the cartridge between the cartridge inlet and the cartridge outlet via the cartridge chamber. The first porous matrix may the second porous matrix may occupy at least 80 percent of the inner volume defined by cartridge chamber.

The disclosure regarding the porous matrix and the heating surface of the heating element may correspondingly apply to the first and second porous matrix and the first and second heating surfaces of the heating element.

The invention further relates to an aerosol-generating system comprising a cartridge as described herein and an aerosol-generating device. The aerosol-generating device comprises a cavity configured to receive the cartridge as described herein.

The aerosol-generating device may comprise a main body and a mouthpiece.

The main body of the aerosol-generating device may comprise a power supply, preferably a battery, for powering the heating element.

The main body of the aerosol-generating device may comprise electric circuitry, preferably comprising a controller, for controlling the supply of electrical energy from the power supply to the heating element.

The cavity of the aerosol-generating device may be arranged at a proximal end of the main body. The cavity may have a hollow cylindrical shape. The cavity may have a circular cross-section. Alternatively, the cavity may have a rectangular or oval cross-section.

The main body may comprise an air inlet. The air inlet may be fluidly connected with the base of the cavity. When a user draws on the mouthpiece, ambient air may be drawn into an airflow channel of the aerosol-generating device through the air inlet. From the airflow channel running through the main body, the air may be drawn into the cavity at one or more apertures at the base of the cavity. This section of the cavity may be referred to as the main body outlet. When the cartridge is received in the cavity, the air may then be drawn into the cartridge through a cartridge inlet. The cartridge inlet may be arranged at a distal end of the cartridge. The air may then be drawn through the cartridge, particularly through the cartridge chamber and subsequently out of the cartridge through the cartridge outlet. The air then enters the mouthpiece, particularly through a mouthpiece inlet. The airflow channel may continue through the mouthpiece towards a mouthpiece outlet. The user may put his or her lips at the mouthpiece outlet to inhale the generated aerosol.

The mouthpiece of the aerosol-generating device may be arranged such that the mouthpiece may close the cavity. Closing the cavity may be performed after insertion of the cartridge into the cavity. In other words, the cartridge may be sandwiched between the main body of the aerosol-generating device and the closed mouthpiece of the aerosol-generating device after insertion of the cartridge into the cavity.

The mouthpiece may be connected to the main body. The mouthpiece may be hingedly connected to the main body. The mouthpiece may be opened in order to allow insertion of the cartridge into the cavity. The mouthpiece may be closed to lock the cartridge in place.

The device may further comprise electrical contacts. The electrical contacts may be arranged at a surface of the cavity. The device further comprises a power supply electrically connected with the electrical contacts. The power supply is configured to supply electrical energy to the heating element of the cartridge, when the cartridge may be received in the cavity.

One or both of the electrical contacts may comprise spring-biased connectors, preferably with rounded terminations. One or both of the electrical contacts may be mounted at the sidewall of the cavity or embedded within the sidewall of the cavity.

The electrical contacts are arranged in the cavity such that they are electrically connected to the pair of cartridge electrical contacts, when the cartridge is received in the cavity. In this way electrical power form the power supply of the aerosol-generating device may be supplied to power the heating element of the cartridge.

A longitudinal axis of an element may extend between a distal end of the element and a proximal end of the element. A longitudinal axis of the cartridge may extend between a distal end of the cartridge and a proximal end of the cartridge. A longitudinal axis of the cartridge chamber may extend between a distal end of the cartridge chamber and a proximal end of the cartridge chamber. A longitudinal axis of the cartridge may extend between the cartridge inlet and the cartridge outlet. 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. The mouth end may be part of the mouthpiece. 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 aerosol-generating 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 aerosolgenerating 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 a cartridge. An aerosol-generating device may be a smoking device that interacts with an aerosol-forming substrate of a cartridge to generate an aerosol that is directly inhalable into a user’s lungs through 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 and a heating chamber.

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 aerosol-forming 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. The heating element may be part of the cartridge. 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- Iron-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 cartridge 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 crosssection. 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, the mouthpiece may be arranged. 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 a cartridge. The cartridge 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 aerosol-forming 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 or tracks on a dielectric substrate, such as polyimide. The flexible heating foils or tracks 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. 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 ‘cartridge’ refers to an element comprising an aerosol-forming substrate that is capable of releasing volatile compounds that can form an aerosol. For example, a cartridge may be a smoking cartridge that generates an aerosol that is directly inhalable into a user’s lungs through the user's mouth. A cartridge 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 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 glycerin 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.

The aerosol-forming substrate may be provided in the form of a fluid, for example a liquid or a gas. The liquid aerosol-forming substrate may contain tobacco or non-tobacco volatile flavour compounds, which are released upon heating of the fluid aerosol-forming substrate.

Preferably, the aerosol-forming substrate comprises an aerosol former.

As used herein, the term 'aerosol former' is used to describe any suitable known compound or mixture of compounds that, in use, facilitates formation of an aerosol and that is substantially resistant to thermal degradation at the operating temperature of the aerosolforming substrate. Suitable aerosol formers are known in the art and include, but are not limited to: polyhydric alcohols, such as propylene glycol, triethylene glycol, 1 ,3-butanediol and glycerine; esters of polyhydric alcohols, such as glycerol mono-, di- or triacetate; and aliphatic esters of mono-, di- or polycarboxylic acids, such as dimethyl dodecanedioate and dimethyl tetradecanedioate.

Preferred aerosol formers are polyhydric alcohols or mixtures thereof, such as propylene glycol, triethylene glycol, 1 ,3-butanediol and, most preferred, glycerin.

The aerosol-forming substrate may comprise a single aerosol former. Alternatively, the aerosol-forming substrate may comprise a combination of two or more aerosol formers.

Preferably, the aerosol-forming substrate has an aerosol former content of greater than 5% on a dry weight basis.

The aerosol aerosol-forming substrate may have an aerosol former content of between approximately 5% and approximately 30% on a dry weight basis. In a preferred embodiment, the aerosol-forming substrate has an aerosol former content of approximately 20% on a dry weight basis.

The article for forming an aerosol may comprise a volatile flavour-generating component. The aerosol forming substrate (for example and/or the carrier material, where provided) may comprise the volatile flavour-generating component. The volatile flavourgenerating component may be at least partially retained in and/or impregnated into and/or located on the surface of the aerosol-forming substrate and/or a carrier material (if such is provided) and/or the cover layer (where provided) and/or the peripheral mould surface thereof.

As used herein the term 'volatile flavour-generating component' is used to describe any volatile component that is added to an aerosol-forming substrate (for example and/or carrier material, where provided) in order to provide a flavourant.

Suitable flavourants include, but are not limited to, materials that contain natural or synthetic menthol, peppermint, spearmint, coffee, tea, spices (such as cinnamon, clove and ginger), cocoa, vanilla, fruit flavours, chocolate, eucalyptus, geranium, eugenol, agave, juniper, anethole, linalool, and the like.

As used herein, the term 'menthol' is used to describe the compound 2-isopropyl-5- methylcyclohexanol in any of its isomeric forms.

Menthol may be used in solid or liquid form. In solid form, menthol may be provided as particles or granules. The term 'solid menthol particles' may be used to describe any granular or particulate solid material comprising at least approximately 80% menthol by weight.

In some embodiments, the article for forming an aerosol (e.g. the aerosol-forming substrate) may be free of menthol.

Preferably, 1.5 mg or more of the volatile flavour-generating component is included in the aerosol-forming substrate.

The volatile flavour-generating component (where provided) may be in the form of a liquid or a solid. The volatile flavour-generating component may be coupled to, or otherwise associated with, a support element. The support element may comprise any suitable substrate or support for locating, holding, or retaining the volatile flavour-generating component. For example, the support element may comprise a fibrous support element, which may be saturated or saturatable with fluid, for example a liquid.

In embodiments, the volatile flavour-generating component may have any suitable structure in which a structural material releasably encloses a flavourant or flavourants. For example, in some preferred embodiments, the volatile flavour-generating component comprises a matrix structure defining a plurality of domains, the flavourant being trapped within the domains until released, for example, when the aerosol-forming substrate is subject to external force. Alternatively, the volatile flavour-generating component may comprise a capsule. Preferably, the capsule comprises an outer shell and an inner core containing the flavourant. Preferably, the outer shell is sealed before the application of an external force, but is frangible or breakable to allow the flavourant to be released when the external force is applied. The capsule may be formed in a variety of physical formations including, but not limited to, a single-part capsule, a multi-part capsule, a single-walled capsule, a multi-walled capsule, a large capsule, and a small capsule.

If the volatile flavour-generating component comprises a matrix structure defining a plurality of domains enclosing the flavourant, the flavourant delivery member may release the flavourant steadily when the aerosol-forming substrate is subject to external force. Alternatively, if the volatile flavour-generating component is a capsule arranged to rupture or burst to release the flavourant when the article for forming an aerosol is subject to external force (for example, but not limited to, if the capsule comprises an outer shell and an inner core), the capsule may have any desired burst strength. The burst strength is the force (exerted on the capsule from the outside of the aerosol-forming substrate) at which the capsule will burst. The burst strength may be a peak in the capsule's force versus compression curve.

The volatile flavour-generating component may be configured to release the flavourant in response to an activation mechanism. Such an activation mechanism may include the application of a force to the volatile flavour-generating component, a change in temperature in the volatile flavour-generating component, a chemical reaction, or any combination thereof.

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 . A cartridge for an aerosol-generating device, the cartridge comprising: a cartridge housing having a cartridge inlet and a cartridge outlet, and a cartridge chamber extending between the cartridge inlet and the cartridge outlet; a heating element for heating an aerosol-forming substrate to form an aerosol, the heating element extending into the cartridge chamber; and a porous matrix configured for retention of a liquid-based aerosol-forming substrate, the porous matrix having a first major surface which is substantially flat, wherein at least a portion of the first major surface of the porous matrix is in direct contact with the heating element.

Example 2. The cartridge according to example 1 , wherein the porous matrix is substantially flat and has a parallelepiped shape.

Example 3. The cartridge according to any of the preceding examples, wherein the porous matrix is formed from organic cotton, cotton, silica, ceramics (AI2O3, ZrO2, SiC, Ca5(PO4)3(OH), 2MgO-2AI2O3-5SiO2), porous metal fibres (stainless steel, nickel, titaniumnickel, iron-chromium-aluminium, etc), metal foams (aluminium, nickel, iron, copper, titanium, etc) cellulose based materials (viscose regenerated films or membranes, foams, aerogels, sponge, sheets), non-woven materials, carbon, polymeric materials (polyamide, polytetrafluorethylene).

Example 4. The cartridge according to any of the preceding examples, wherein the porous matrix has a pore size of between 10 micrometers to 500 micrometers, wherein the porous matrix has a pore size of between 20 micrometers to 250 micrometers, wherein the porous matrix has a pore size of between 30 micrometers to 150 micrometers.

Example 5. The cartridge according to any of the preceding examples, wherein the porous matrix comprises pores, which pores are designed to store and transport a liquid aerosol-forming substrate.

Example 6. The cartridge according to any of the preceding examples, wherein the porous matrix is constructed from one or more layers of porous matrix material.

Example 7. The cartridge according to any of the preceding examples, wherein the porous matrix is constructed from a plurality of layers of porous matrix material, and wherein the layers are made from at least two different porous matrix materials.

Example 8. The cartridge according to any of the preceding examples, wherein the different porous matrix materials may have different material properties.

Example 9. The cartridge according to any of the preceding examples, wherein the different material properties may differ in one or more properties selected from: temperature resistance, porosity and average pore size.

Example 10. The cartridge according to any of the preceding examples, wherein the porous matrix may be formed from a plurality of layers of porous matrix material, wherein the average pore size of the layers of porous matrix material decreases the closer the layer of porous matrix material is located to the heating element.

Example 11. The cartridge according to any of the preceding examples, wherein the heating element is a resistive heating element.

Example 12. The cartridge according to any one of the preceding examples, wherein the heating element is a planar heating element.

Example 13. The cartridge according to any one of the preceding examples, wherein the planar heating element comprises one or more planar heating surfaces for heating the aerosol-forming substrate to form an aerosol.

Example 14. The cartridge according to any one of the preceding examples, wherein the planar heating element comprises two planar heating surfaces for heating the aerosolgenerating substrate to form an aerosol. Example 15. A cartridge according to any one of examples 11 to 14, wherein a ratio of the surface area of each of the one or more planar heating surfaces to the cross-sectional area of the cartridge chamber in the plane in which the planar heating element extends is at least 0.3.

Example 16. The cartridge according to any of the preceding examples, wherein the porous matrix is positioned in contact with each planar heating surface of the heating element.

Example 17. The cartridge according to any of the preceding examples, wherein an operating temperature of the heating element is between 200 degrees Celsius to 350 degrees Celsius, wherein an operating temperature of the heating element is between 220 degrees Celsius to 290 degrees Celsius.

Example 18. The cartridge according to any one of examples 11 to 17, wherein the heating element is electrically connected to a pair of cartridge electrical contacts.

Example 19. The cartridge according to example 18, wherein the cartridge electrical contacts are provided at an outer surface of the cartridge housing.

Example 20. The cartridge according to any of the preceding examples, wherein the cartridge housing is formed from food contact rated plastic such as polycarbonate, ABS, liquid crystal polymer, copolyester plastic, from plant-based materials such as wood or bamboo and/or from high temperature plastics, such as liquid crystal polymer, polyetheretherketone, or cyclic olefin copolymer.

Example 21. An aerosol-generating system comprising a cartridge according to any of the preceding examples, and an aerosol-generating device wherein the aerosol-generating device comprises a cavity configured to receive the cartridge.

Example 22. The aerosol-generating system according to example 21 , wherein the aerosol-generating device comprises a main body and a mouthpiece an aerosol-generating device, and wherein the cavity is arranged between a main body and a mouthpiece of the aerosol-generating device.

Example 23. The aerosol-generating system according to any one of examples 21 to

22, wherein the mouthpiece is configured to be arranged covering the cavity to enclose the cartridge, when the cartridge is received in the cavity.

Example 24. The aerosol-generating system according to any one of examples 21 to

23, wherein electrical contacts are provided in the cavity, via which electrical power is supplied to the pair of cartridge electrical contacts.

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 sectional side view of an aerosol-generating system comprising an aerosol-generating device and a removable cartridge;

Fig. 2 shows a proximal section of the aerosol-generating device with a closed mouthpiece;

Fig. 3 shows a cross section of a cartridge with heating element;

Fig. 4 shows the insertion of the cartridge into a cavity of the aerosol-generating device;

Fig. 5 shows a plan cross-sectional view of a cartridge; and

Fig. 6 shows a plan cross-sectional view of a cartridge comprising a multi-layer porous matrix.

Figure 1 shows an aerosol-generating system 10 comprising the aerosol-generating device. The aerosol generating device comprises a main body 12 and the mouthpiece 14. The aerosol-generating system 10 further comprises a cartridge 16.

The main body 12 of the aerosol-generating device comprises a power supply 18 in the form of a battery and a controller 20 for controlling the supply of electrical energy from the power supply 18 to the cartridge 16. More specifically, the power supplied from the power supply 18 to the heating element (not shown in Figure 1) of the cartridge 16.

The cartridge 16 can be inserted into a cavity 22 of the main body 12 of the aerosolgenerating device. The cavity 22 is arranged at a proximal end of the main body 12.

The mouthpiece 14 is hingedly connected with the main body 12. When the cartridge 16 is inserted into the cavity 22 of the main body 12, the mouthpiece 14 may be closed so that the cartridge 16 is sandwiched between the main body 12 and the mouthpiece 14.

The closed configuration of the mouthpiece 14 is shown in Figure 2. The cartridge 16 is received in the cavity 22 of the main body 12. Further, the mouthpiece 14 closes off the proximal end of the cartridge 16.

At a base 24 of the cavity 22, a main body outlet 26 is arranged. The main body outlet 26 allows airflow into the cavity 22. The main body outlet 26 is fluidly connected with an airflow channel (not shown) of the main body 12 which, in turn, is fluidly connected with an air inlet (not shown) of the main body 12 allowing ambient air to be drawn into the main body 12 and into the cavity 22. The main body outlet 26 is fluidly connected with a cartridge inlet 28. Hence, ambient air can be drawn into the cartridge 16 via the cartridge inlet 28. The cartridge inlet 28 is arranged at a distal end of the cartridge 16.

The cartridge 16 comprises aerosol-forming substrate. The aerosol-forming substrate is arranged in the cartridge chamber.

After traveling through the cartridge 16, the vaporized aerosol-forming substrate entrained in the airflow exits the cartridge 16 via a cartridge outlet 30. The cartridge outlet 30 is arranged at a proximal end of the cartridge 16.

The cartridge 16 further comprises a heating element (shown in Figure 3) for heating the aerosol-forming substrate of the cartridge 16 so that the aerosol-forming substrate can be vaporized.

Downstream of the cartridge outlet 30, the air 32 enters a mouthpiece inlet 34 and travels through the mouthpiece 14. At a proximal end of the mouthpiece 14, the aerosol exits the mouthpiece 14 at the mouthpiece outlet 36 for inhalation by a user.

Figure 3 shows a cross-sectional view of a cartridge 16 according to the present invention. At a proximal end of the cartridge 16, proximal air openings 40 are provided while at a distal end 42 of the cartridge 16, distal air openings 44 are provided. The air openings enable airflow into the cartridge 16 and out of the cartridge 16.

Figure 3 further shows electrical contacts 48 provided at the distal end 42 of the cartridge 16. Via the electrical contacts 48 electrical energy from the power supply 20 may be provided to the heating element 46 of the cartridge 16. The heating element 46 comprises a meandering heating track. The meandering heating track extends substantially in a plane that is parallel to the side walls of the cartridge. The meandering heating track thus defines a planar heating surface on either side of the resistive heating element 46.

Figure 4 shows the insertion of the cartridge 16 of Figure 3 into the cavity 22 of the aerosol-generating device. As shown in Figure 4, upon insertion of the cartridge 16 into the cavity 22, the cartridge electrical contact 48 provided at the distal end 42 of the cartridge 16 come into contact with corresponding electrical contacts 50 provided at the base 24 of the cavity 22 of the aerosol-generating device. The electrical contacts 50 are connected to the power supply 20 via electrical wiring 54.

Figure 5 shows a schematic representation of an exemplary embodiment of a porous matrix 60. As shown in the upper view of Figure 5, the porous matrix 60 is of a substantially flat rectangular shape with a Width W a Length L and a Thickness T1 . In this case the porous matrix is made from organic cotton and has a pore size of about 50 micrometers.

The lower view of Figure 5 shows a plan cross sectional view of an exemplary embodiment of a cartridge 16 with the porous matrix 60. The cartridge 16 comprises a housing 62 defining a cartridge chamber 64. In the center of the cartridge chamber 64 the heating element 46 is provided. On either side of the heating element 46 a porous matrix 60 is provided. In more detail, the porous matrix 60 containing liquid aerosol-forming substrate is positioned such that one of its major surfaces is in direct contact with one of the heating surfaces 66, 68 of the resistive heating element 46.

Figure 6 shows a schematic representation of an exemplary embodiment of a porous matrix 70 that is formed from a plurality of layers of porous matrix material 60. The porous matrix 70 is again of a substantially flat rectangular shape with a Width W a Length L and a Thickness T2. The lower view of Figure 6 again shows a plan cross sectional view of an exemplary embodiment of a cartridge 16 with the porous matrix 70. A portion of porous matrix 70 is provided on either side of the heating element 46.

Claims

1. A cartridge for an aerosol-generating device, the cartridge comprising: a cartridge housing having a cartridge inlet and a cartridge outlet, and a cartridge chamber extending between the cartridge inlet and the cartridge outlet; a heating element for heating an aerosol-forming substrate to form an aerosol, the heating element extending into the cartridge chamber; and a porous matrix configured for retention of a liquid-based aerosol-forming substrate, the porous matrix having a first major surface which is substantially flat, wherein at least a portion of the first major surface of the porous matrix is in direct contact with the heating element.

2. The cartridge according to claim 1 , wherein the porous matrix is substantially flat and has a parallelepiped shape.

3. The cartridge according to any of the preceding claims, wherein the porous matrix has a pore size of between 10 micrometers to 500 micrometers, wherein the porous matrix has a pore size of between 20 micrometers to 250 micrometers, wherein the porous matrix has a pore size of between 30 micrometers to 150 micrometers.

4. The cartridge according to any of the preceding claims, wherein the porous matrix is constructed from one or more layers of porous matrix material.

5. The cartridge according to any of the preceding claims, wherein the porous matrix is constructed from a plurality of layers of porous matrix material, and wherein the layers are made from at least two different porous matrix materials.

6. The cartridge according to any of the preceding claims, wherein the different porous matrix materials may have different material properties.

7. The cartridge according to any of the preceding claims, wherein the porous matrix may be formed from a plurality of layers of porous matrix material, wherein the average pore size of the layers of porous matrix material decreases the closer the layer of porous matrix material is located to the heating element.

8. The cartridge according to any of the preceding claims, wherein the heating element is a resistive heating element.

9. The cartridge according to any one of the preceding claims, wherein the heating element is a planar heating element.

10. The cartridge according to any of the preceding claims, wherein the porous matrix is positioned in contact with each planar heating surface of the heating element.

11. The cartridge according to any one of claims 8 to 10, wherein the heating element is electrically connected to a pair of cartridge electrical contacts.

12. An aerosol-generating system comprising a cartridge according to any of the preceding claims, and an aerosol-generating device wherein the aerosol-generating device comprises a cavity configured to receive the cartridge.

13. The aerosol-generating system according to claim 12, wherein the aerosolgenerating device comprises a main body and a mouthpiece an aerosol-generating device, and wherein the cavity is arranged between a main body and a mouthpiece of the aerosolgenerating device.

14. The aerosol-generating system according to any one of claims 12 to 13, wherein the mouthpiece is configured to be arranged covering the cavity to enclose the cartridge, when the cartridge is received in the cavity.

15. The aerosol-generating system according to any one of claims 12 to 14, wherein electrical contacts are provided in the cavity, via which electrical power is supplied to the pair of cartridge electrical contacts.