WO2025036904A1

WO2025036904A1 - Aerosol-generating element containing tobacco particles

Info

Publication number: WO2025036904A1
Application number: PCT/EP2024/072815
Authority: WO
Inventors: Alexandre REDONDO; Anzhelika SIMONYAN
Original assignee: Philip Morris Products SA
Current assignee: Philip Morris Products SA
Priority date: 2023-08-14
Filing date: 2024-08-13
Publication date: 2025-02-20
Anticipated expiration: 2026-02-14

Abstract

There is provided an aerosol-generating element (10, 20, 30, 40) for use in an aerosol-generating article or system. The aerosol-generating element (10, 20, 30, 40) comprises: an inner core (12) of an aerosol-generating substrate, the aerosol-generating substrate comprising tobacco particles and a liquid solvent comprising one or more aerosol formers; and an outer shell encapsulating the inner core of aerosol-generating substrate, the outer coating comprising at least one film-forming polymer. The aerosol-generating substrate comprises at least 20 percent by weight of tobacco particles and at least 30 percent by weight of the one or more aerosol formers, on a dry weight basis. A weight ratio of tobacco particles to liquid solvent in the aerosol-generating substrate is at least 0.3.

Description

AEROSOL-GENERATING ELEMENT CONTAINING TOBACCO PARTICLES

The present disclosure relates to an aerosol-generating element of the type for use in an aerosol-generating article or system.

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

Typically, aerosol-generating articles in which tobacco is heated rather than combusted further comprise one or more elements paired with the aerosol-generating substrate. For example, aerosol-generating articles have been proposed which include a rod of tobaccocontaining substrate and one or more of a support element adapted to impart increased structural to the aerosol-generating article, an aerosol-cooling element configured to lower the temperature of the aerosol prior to the aerosol reaching a mouth end of the aerosol-generating article, and a mouthpiece element.

After an aerosol-generating article has been smoked and discarded, it would generally be desirable for its components to break down as quickly as possible. However, some of the materials most ordinarily used in aerosol-generating articles, such as cellulose acetate, are not easily biodegradable, and so they can persist in the environment for years. As a result, elements included in aerosol-generating articles in combination with tobacco-containing rods may have an undesirable tendency to accumulate in the environment. For example, used cigarette filters formed from cellulose acetate are among the most commonly retrieved plastic items in beach clean-up activities. Additionally, the manufacture of similar additional element generally involves a fairly significant consumption of resources (such as water, energy, etc.). Thus, a need is generally felt to provide more sustainable alternatives to existing aerosol-generating articles that comprise a plurality of additional elements such as, in particular, filter or mouthpiece components.

More recently, an aerosol-generating element has been described, which is in fact a discrete aerosol-generating substrate in solid form, within which an aerosol-generating formulation is encapsulated. It has been proposed that a plurality of aerosol-generating elements of this type be provided within a cavity defined by a tubular element, such that an outer surface of the aerosol-generating elements is exposed inside the longitudinal airflow channel defined by the cavity. Upon heating, an aerosol can be generated from the aerosol-generating elements and released into the airflow channel to be drawn through the tubular element into the consumer’s mouth.

It would be desirable to provide an aerosol-generating element that does not require to be combined with any additional elements in order to be used to generate an aerosol, as this would have less of an environmental impact, particularly in terms of post-consumption waste management.

Further, it would be desirable to provide such an aerosol-generating element that can be manufactured more sustainably, such as by reducing the overall consumption of resources and materials.

The present disclosure relates to an aerosol-generating element for use in an aerosolgenerating article or system.

The aerosol-generating element may comprise an inner core of an aerosol-generating substrate.

The aerosol-generating substrate may comprise tobacco particles.

The aerosol-generating substrate may comprise a liquid solvent comprising one or more aerosol formers.

The aerosol-generating element may further comprise an outer shell encapsulating the inner core of aerosol-generating substrate.

The outer coating may comprise at least one film-forming polymer.

The aerosol-generating substrate may comprise at least 20 percent by weight of tobacco particles, on a dry weight basis.

The aerosol-generating substrate may comprise at least 30 percent by weight of the one or more aerosol formers, on a dry weight basis.

A weight ratio of tobacco particles to liquid solvent in the aerosol-generating substrate may be at least 0.3.

The present disclosure also relates to an aerosol-generating article comprising an aerosolgenerating element as described above.

According to a first aspect of the present invention, there is provided an aerosol-generating element for use in an aerosol-generating article or system, the aerosol-generating element comprising: an inner core of an aerosol-generating substrate, the aerosol-generating substrate comprising tobacco particles and a liquid solvent comprising one or more aerosol formers; and an outer shell encapsulating the inner core of aerosol-generating substrate, the outer coating comprising at least one film-forming polymer, wherein the aerosol-generating substrate comprises at least 20 percent by weight of tobacco particles and at least 30 percent by weight of the one or more aerosol formers, on a dry weight basis, wherein a weight ratio of tobacco particles to liquid solvent in the aerosol-generating substrate is at least 0.3. The combination of tobacco particles with a solvent comprising one or more aerosol formers in the relative proportions described herein has been found to provide an aerosol-generating substrate that can advantageously be formed stably into virtually any shape. Without wishing to be bound by theory, this is understood to be a consequence of the aerosol-generating substrate having a paste-like consistency, that allows the aerosol-generating substrate to be imparted a predetermined shape, for example by using a mould, and to retain the imparted shape, even when the shaped aerosol-generating substrate is removed from the mould.

Notably, only very small amounts of water (if any water is needed at all) are required for the manufacture of an aerosol-generating element according to the present invention. Accordingly, aerosol-generating elements in accordance with the present invention are in and of themselves more sustainable than certain existing aerosol-generating products.

Additionally, the provision of the outer shell encapsulating the inner core makes the aerosolgenerating substrate easy to handle and transport as part of the aerosol-generating element. At the same time, the outer shell protects the aerosol-generating substrate from the outer environment, at least until the aerosol-generating element is used. Thus, the aerosol-generating substrate may conveniently be preserved prior to use of the aerosol-generating element without requiring additional elements to establish a barrier between the aerosol-generating substrate and outer agents that may undesirably impact its properties.

Aerosol-generating elements according to the present invention can be heated directly in an aerosol-generating device without requiring to be combined with any additional element to form an aerosol-generating article. Therefore, compared with existing aerosol-generating products, the manufacturing process is greatly simplified and generally made more sustainable. Waste generation both pre- and post-use is reduced, and waste management is as a result greatly simplified.

Further, costs associated with storage and transportation may also be reduced compared with certain existing aerosol-generating products.

It is worth noting that aerosol-generating elements in accordance with the present invention may, at any rate, be incorporated in an aerosol-generating article for use with an aerosolgenerating device, and so the present invention also provides the potential for a variety of article designs.

Thus, the present disclosure also relates to an aerosol-generating article comprising an aerosol-generating element as described above.

According to a second aspect of the present invention, there is provided an aerosolgenerating article comprising an aerosol-generating element according to the first aspect of the present invention. Aerosol-generating articles incorporating one or more aerosol-generating elements in accordance with the present invention may generally benefit from the improved sustainability associated with the manufacturing of the aerosol-generating elements.

GENERAL DEFINITIONS

As used herein with reference to the invention, the term “aerosol-generating substrate” is used to describe a substrate comprising aerosol-generating material that is capable of releasing upon heating volatile compounds that can generate an aerosol.

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

As used herein, the term “aerosol-generating element” refers to a discrete aerosolgenerating substrate in solid form, which comprises an aerosol-generating inner core encapsulated within a shell. The structure and composition of the aerosol-generating element will be described in more detail below. The aerosol-generating element as such can be heated to generate an inhalable aerosol for delivery to a user.

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

As used herein with reference to the invention, the term “aerosol-generating device” is used to describe a device that interacts with the aerosol-generating substrate of the aerosol-generating element to generate an aerosol. The term “aerosol-generating system” may be used to denote a system comprising such an aerosol-generating device and an aerosol-generating element or an aerosol-generating article including one or more aerosol-generating elements.

STATEMENTS RELATING TO THE DEPENDENT “ELEMENT” CLAIMS

As described briefly above, an aerosol-generating element according to the present invention comprises an inner core of an aerosol-generating substrate and an outer shell encapsulating the inner core of aerosol-generating substrate, wherein the aerosol-generating substrate comprises tobacco particles and a liquid solvent comprising one or more aerosol formers.

The aerosol-generating substrate may have a viscosity of up to 22,000 cp.

The term “viscosity” is used herein to denote a measure of a fluid’s internal resistance to deformation under shear stress. In more detail, the term “viscosity” as used herein refers to a fluid’s dynamic viscosity (p). The physical unit for dynamic viscosity in the centimetre gram second system of units (cgs) is the poise (P). 1 poise = 100 centipoise = 0.1 Pa s. In more detail, the term “viscosity” denotes the dynamic viscosity of the aerosol-generating substrate as measured at 23 degrees Celsius and at a shear rate of 100 reciprocal seconds (1/s) during a linear ramp from 1 to 200 reciprocal seconds, using a MCR302 Anton Paar rheometer with a PP25 geometry, the rheometer equipped with a peltier module P-PTD2000 with a VT2 cooling system.

Preferably, the viscosity of the aerosol-generating substrate is less than or equal to 20,000 cp. More preferably, the viscosity of the aerosol-generating substrate is less than or equal to 15,000 cp. Even more preferably, the viscosity of the aerosol-generating substrate is less than or equal to 10,000 cp.

The aerosol-generating substrate may have a viscosity of at least 5,000 cp. Preferably, the viscosity of the aerosol-generating substrate is at least 6,000 cp. More preferably, the viscosity of the aerosol-generating substrate is at least 7,000 cp. Even more preferably, the viscosity of the aerosol-generating substrate is at least 8,000 cp.

In some embodiments, the viscosity of the aerosol-generating substrate is from 5,000 cp to 22,000 cp, preferably from 5,000 cp to 20,000 cp, more preferably from 5,000 cp to 15,000 cp, even more preferably from 5,000 cp to 10,000 cp.

In certain embodiments, the viscosity of the aerosol-generating substrate is from 6,000 cp to 22,000 cp, preferably from 6,000 cp to 20,000 cp, more preferably from 6,000 cp to 15,000 cp, even more preferably from 6,000 cp to 10,000 cp.

In other embodiments, the viscosity of the aerosol-generating substrate is from 7,000 cp to 22,000 cp, preferably from 7,000 cp to 20,000 cp, more preferably from 7,000 cp to 15,000 cp, even more preferably from 7,000 cp to 10,000 cp.

In further embodiments, the viscosity of the aerosol-generating substrate is from 8,000 cp to 22,000 cp, preferably from 8,000 cp to 20,000 cp, more preferably from 8,000 cp to 15,000 cp, even more preferably from 8,000 cp to 10,000 cp.

Without wishing to be bound by theory, it has been observed that imparting a shape to the aerosol-generating element when the aerosol-generating substrate has a viscosity within the ranges described above is particularly easy, as the paste-like consistency of the aerosolgenerating substrate enables the aerosol-generating substrate to be formed into a variety of shapes. Additionally, it has been observed that an aerosol-generating substrate having a viscosity within the ranges described above can consistently hold its shape during subsequent manufacturing steps. For example, as will be described in more detail below, extracting the aerosol-generating substrate from a mould prior to dipping the shaped aerosol-generating substrate in a film-forming polymer to form the outer shell does not significantly alter the shape imparted to the aerosol-generating substrate. As such, when the outer shell is formed to encapsulate an inner core of aerosol-generating substrate, the overall shape previously imparted to the aerosol-generating substrate is maintained and found substantially unchanged in the formed aerosol-generating element.

A weight ratio of tobacco particles to liquid solvent in the aerosol-generating substrate may be less than or equal to 2. Preferably, a weight ratio of tobacco particles to liquid solvent in the aerosol-generating substrate is less than or equal to 1.5. More preferably, a weight ratio of tobacco particles to liquid solvent in the aerosol-generating substrate is less than or equal to 1.25. Even more preferably, a weight ratio of tobacco particles to liquid solvent in the aerosol-generating substrate is less than or equal to 1.2.

Preferably, a weight ratio of tobacco particles to liquid solvent in the aerosol-generating substrate is at least 0.5. More preferably, a weight ratio of tobacco particles to liquid solvent in the aerosol-generating substrate is at least 0.75. Even more preferably, a weight ratio of tobacco particles to liquid solvent in the aerosol-generating substrate is at least 1.

In some embodiments, a weight ratio of tobacco particles to liquid solvent in the aerosolgenerating substrate is from 0.3 to 2, preferably from 0.3 to 1.5, more preferably from 0.3 to 1.25, even more preferably from 0.3 to 1.2.

In certain embodiments, a weight ratio of tobacco particles to liquid solvent in the aerosolgenerating substrate is from 0.5 to 2, preferably from 0.5 to 1.5, more preferably from 0.5 to 1.25, even more preferably from 0.5 to 1.2.

In other embodiments, a weight ratio of tobacco particles to liquid solvent in the aerosolgenerating substrate is from 0.75 to 2, preferably from 0.75 to 1.5, more preferably from 0.75 to 1.25, even more preferably from 0.75 to 1.2.

In further embodiments, a weight ratio of tobacco particles to liquid solvent in the aerosolgenerating substrate is from 1 to 2, preferably from 1 to 1.5, more preferably from 1 to 1.25, even more preferably from 1 to 1.2.

Weight ratios of tobacco particles to liquid solvent in the aerosol-generating substrate within the ranges described above have the benefit that a tobacco content within the aerosol-generating substrate may advantageously be maximised, whilst at the same time contributing to keeping the density and viscosity of the aerosol-generating substrate at values that ensure a paste-like consistency compatible with easy and reliable shaping of the aerosol-generating elements during manufacturing.

Preferably, the aerosol-generating substrate is an aerosol-generating suspension of the tobacco particles in the liquid solvent. As used herein, the term “aerosol-generating suspension” refers to a suspension that is capable of releasing upon heating volatile compounds, which can form an aerosol. The aerosol-generating suspension is a heterogeneous mixture in which the tobacco particles are not dissolved, but get suspended throughout the bulk of the solvent containing the one or more aerosol formers, and are left dispersed within the solvent. In other words, the tobacco particles substantially do not settle and may remain homogenously distributed throughout the bulk of the solvent. This may beneficially impact mass transfer mechanisms involved in the generation and release of aerosol particles upon heating the aerosol-generating element.

In particular, the aerosol-generating suspension is not a gel and does not include a gelling agent.

A density of the aerosol-generating substrate may be at least 0.75 grams per cubic centimetre. Preferably, a density of the aerosol-generating substrate is at least 1 gram per cubic centimetre. More preferably, a density of the aerosol-generating substrate is at least 1.1 grams per cubic centimetre. Even more preferably, a density of the aerosol-generating substrate is at least 1 .2 grams per cubic centimetre.

A density of the aerosol-generating substrate may be less than or equal to 2.25 grams per cubic centimetre. Preferably, a density of the aerosol-generating substrate is less than or equal to 2 grams per cubic centimetre. More preferably, a density of the aerosol-generating substrate is less than or equal to 1 .9 grams per cubic centimetre. Even more preferably, a density of the aerosol-generating substrate is less than or equal to 1.8 grams per cubic centimetre.

In some embodiments, a density of the aerosol-generating substrate is from 0.75 grams per cubic centimetre to 2.25 grams per cubic centimetre, preferably from 1 gram per cubic centimetre to 2.25 grams per cubic centimetre, more preferably from 1.1 grams per cubic centimetre to 2.25 grams per cubic centimetre, even more preferably from 1 .2 grams per cubic centimetre to 2.25 grams per cubic centimetre.

In certain embodiments, a density of the aerosol-generating substrate is from 0.75 grams per cubic centimetre to 2 grams per cubic centimetre, preferably from 1 gram per cubic centimetre to 2 grams per cubic centimetre, more preferably from 1.1 grams per cubic centimetre to 2 grams per cubic centimetre, even more preferably from 1 .2 grams per cubic centimetre to 2 grams per cubic centimetre.

In other embodiments, a density of the aerosol-generating substrate is from 0.75 grams per cubic centimetre to 1 .9 grams per cubic centimetre, preferably from 1 gram per cubic centimetre to 1.9 grams per cubic centimetre, more preferably from 1.1 grams per cubic centimetre to 1.9 grams per cubic centimetre, even more preferably from 1.2 grams per cubic centimetre to 1.9 grams per cubic centimetre.

In further embodiments, a density of the aerosol-generating substrate is from 0.75 grams per cubic centimetre to 1.8 grams per cubic centimetre, preferably from 1 gram per cubic centimetre to 1.8 grams per cubic centimetre, more preferably from 1.1 grams per cubic centimetre to 1 .8 grams per cubic centimetre, even more preferably from 1 .2 grams per cubic centimetre to 1 .8 grams per cubic centimetre.

Generally speaking, there is no direct correlation between density and viscosity of a fluid. However, both density and viscosity are impacted by temperature changes. For example, when the temperature of a fluid is increased, the particles in the fluid have a tendency to move apart, which causes a decrease in both density and viscosity. Aerosol-generating elements wherein the aerosol-generating substrate has a density within the ranges described above have the benefit that they easily maintain their structure and shape even after being used. Thus, adjusting the density of the aerosol-generating substrate to be in the ranges described above has the benefit that the aerosol-generating elements comprising the aerosol-generating substrate maintain their integrity even after exposure to heat under the regular operating conditions of the aerosolgenerating device has altered the original density and viscosity, and even after part of the one or more aerosol formers has been released during use.

COMPOSITION OF THE AEROSOL-GENERATING SUBSTRATE - TOBACCO PARTICLES

The aerosol-generating substrate preferably comprises at least 35 percent by weight of tobacco particles, on a dry weight basis, more preferably at least 40 percent by weight of tobacco particles, on a dry weight basis, even more preferably 45 percent by weight of tobacco particles, on a dry weight basis. In particularly preferred embodiments, the aerosol-generating substrate comprises at least 50 percent by weight of tobacco particles, on a dry weight basis.

The aerosol-generating substrate may comprise up to 70 percent by weight of tobacco particles, on a dry weight basis. Preferably, the aerosol-generating substrate comprises less than or equal to 65 percent by weight of tobacco particles, on a dry weight basis. More preferably, the aerosol-generating substrate comprises less than or equal to 60 percent by weight of tobacco particles, on a dry weight basis.

In some embodiments, the aerosol-generating substrate comprises from 35 percent by weight to 70 percent by weight of tobacco particles, on a dry weight basis. Preferably, the aerosolgenerating substrate comprises from 40 percent by weight to 70 percent by weight of tobacco particles, on a dry weight basis. More preferably, the aerosol-generating substrate comprises from 45 percent by weight to 70 percent by weight of tobacco particles, on a dry weight basis. Even more preferably, the aerosol-generating substrate comprises from 50 percent by weight to 70 percent by weight of tobacco particles, on a dry weight basis.

In certain embodiments, the aerosol-generating substrate comprises from 35 percent by weight to 65 percent by weight of tobacco particles, on a dry weight basis. Preferably, the aerosolgenerating substrate comprises from 40 percent by weight to 65 percent by weight of tobacco particles, on a dry weight basis. More preferably, the aerosol-generating substrate comprises from 45 percent by weight to 65 percent by weight of tobacco particles, on a dry weight basis. Even more preferably, the aerosol-generating substrate comprises from 50 percent by weight to 65 percent by weight of tobacco particles, on a dry weight basis.

In other embodiments, the aerosol-generating substrate comprises from 35 percent by weight to 60 percent by weight of tobacco particles, on a dry weight basis. Preferably, the aerosol- generating substrate comprises from 40 percent by weight to 60 percent by weight of tobacco particles, on a dry weight basis. More preferably, the aerosol-generating substrate comprises from 45 percent by weight to 60 percent by weight of tobacco particles, on a dry weight basis. Even more preferably, the aerosol-generating substrate comprises from 50 percent by weight to 60 percent by weight of tobacco particles, on a dry weight basis.

By adjusting the amount of tobacco particles in the aerosol-generating substrate it may be advantageously possible to finely tune viscosity and density of the aerosol-generating substrate. This has, in turn, an impact on density and viscosity of the aerosol-generating substrate.

Further, one may beneficially control the relative proportion of tobacco particles and the one or more aerosol formers in the solvent, which may have an impact on the composition of the aerosol generated and delivered to the consumer during use. Thus, by adjusting the content of tobacco particles in the aerosol-generating substrate, it may be advantageously possible to fine tune the delivery of certain aerosol species to the consumer during use.

The tobacco particles may have an average particle size of at least 25 microns. Preferably, the tobacco particles have an average particle size of at least 30 microns. More preferably, the tobacco particles have an average particle size of at least 35 microns. Even more preferably, the tobacco particles have an average particle size of at least 40 microns.

Use of tobacco particles having an average particle size of 25 microns or more may help control how easily the tobacco particles may be dispersed and kept in suspension within the solvent, which helps in providing an homogenous distribution of tobacco particles throughout the inner core of the aerosol-generating element.

The tobacco particles may have an average size of up to 250 microns. Preferably, the tobacco particles have an average size of less than or equal to 200 microns. More preferably, the tobacco particles have an average size of less than or equal to 180 microns. Even more preferably, the tobacco particles have an average size of less than or equal to 160 microns. Most preferably, the tobacco particles have an average size of less than or equal to 140 microns.

In some embodiments, the tobacco particles have an average size of from 30 microns to 200 microns, preferably from 35 microns to 200 microns, more preferably from 40 microns to 200 microns. In other embodiments, the tobacco particles have an average size of from 30 microns to 180 microns, preferably from 35 microns to 180 microns, more preferably from 40 microns to 180 microns. In further embodiments, the tobacco particles have an average size of from 30 microns to 160 microns, preferably from 35 microns to 160 microns, more preferably from 40 microns to 160 microns. In yet other embodiments, the tobacco particles have an average size of from 30 microns to 140 microns, preferably from 35 microns to 140 microns, more preferably from 40 microns to 140 microns.

Advantageously, using tobacco particles size having an average size within the ranges described above has a beneficial impact on flowability and malleability of the inner core material, and may also enable some desirable control over porosity of the formed aerosol-generating element, which helps in release of the aerosol species during use.

The tobacco particles may have a D90 value of up to 140 microns. This expression means that 90 percent of the tobacco particles in the aerosol-generating substrate have a size of less than or equal to 140 microns. For a population of particles, the D90 value may be determined by analysing the particle size distribution. In more detail, looking at a particle size distribution curve, the D90 value can be determined by identifying the point on the curve below which 90 percent of the particles fall.

Preferably, the tobacco particles have a D90 value of less than or equal to 120 microns. More preferably, the tobacco particles have a D90 value of less than or equal to 100 microns. Even more preferably, the tobacco particles have a D90 value of less than or equal to 90 microns. In particularly preferable embodiments, the tobacco particles have a D90 value of less than or equal to 80 microns or less than or equal to 70 microns.

The tobacco particles may have a D90 value of at least 35 microns. Preferably, the tobacco particles have a D90 value of at least 40 microns. More preferably, the tobacco particles have a D90 value of at least 45 microns. Even more preferably, the tobacco particles have a D90 value of at least 50 microns.

The particle size distribution may be determined by laser diffraction. For example, the particle size distribution may be determined by laser diffraction using a Malvern Mastersizer 3000 laser diffraction particle size analyser in accordance with the manufacturer’s instructions.

Using tobacco particles having a D90 value falling within the ranges described above has the benefit that a regular particle distribution is achieved in the aerosol-generating element. This may facilitate controlling the porosity of the aerosol-generating element, which helps in release of the aerosol species during use. Additionally, this helps ensure that a consistent aerosol can be generated from the aerosol-generating element upon heating.

Preferably, the tobacco particles are substantially homogeneously distributed through the aerosol-generating substrate.

COMPOSITION OF THE AEROSOL-GENERATING SUBSTRATE - AEROSOL FORMERS

Preferably, the aerosol-generating substrate comprises at least 35 percent by weight of the one or more aerosol formers, on a dry weight basis. More preferably, the aerosol-generating substrate comprises at least 40 percent by weight of the one or more aerosol formers, on a dry weight basis.

Preferably, the aerosol-generating substrate comprises less than or equal to 75 percent by weight of the one or more aerosol formers, on a dry weight basis. More preferably, the aerosolgenerating substrate comprises less than or equal to 70 percent by weight of the one or more aerosol formers, on a dry weight basis. Even more preferably, the aerosol-generating substrate comprises less than or equal to 65 percent by weight of the one or more aerosol formers, on a dry weight basis. In particularly preferred embodiments, the aerosol-generating substrate comprises less than or equal to 60 percent by weight of the one or more aerosol formers, on a dry weight basis.

In some embodiments, the aerosol-generating substrate comprises from 35 percent by weight to 75 percent by weight of the one or more aerosol formers, on a dry weight basis. Preferably, the aerosol-generating substrate comprises from 35 percent by weight to 70 percent by weight of the one or more aerosol formers, on a dry weight basis. More preferably, the aerosolgenerating substrate comprises from 35 percent by weight to 65 percent by weight of the one or more aerosol formers, on a dry weight basis. Even more preferably, the aerosol-generating substrate comprises from 35 percent by weight to 60 percent by weight of the one or more aerosol formers, on a dry weight basis.

In certain embodiments, the aerosol-generating substrate comprises from 40 percent by weight to 75 percent by weight of the one or more aerosol formers, on a dry weight basis. Preferably, the aerosol-generating substrate comprises from 40 percent by weight to 70 percent by weight of the one or more aerosol formers, on a dry weight basis. More preferably, the aerosolgenerating substrate comprises from 40 percent by weight to 65 percent by weight of the one or more aerosol formers, on a dry weight basis. Even more preferably, the aerosol-generating substrate comprises from 40 percent by weight to 60 percent by weight of the one or more aerosol formers, on a dry weight basis.

By adjusting the amount of aerosol former or aerosol formers in the aerosol-generating substrate it may be advantageously possible to finely tune viscosity and density of the aerosolgenerating substrate. This has, in turn, an impact on density and viscosity of the aerosolgenerating substrate.

Further, one may beneficially control the relative proportion of tobacco particles and the one or more aerosol formers in the solvent, which may have an impact on the composition of the aerosol generated and delivered to the consumer during use. Thus, by adjusting the content of aerosol former or aerosol formers in the aerosol-generating substrate, it may be advantageously possible to fine tune the delivery of certain aerosol species to the consumer during use.

Suitable aerosol former for use in the manufacture of aerosol-generating elements according to the present disclosure include, but are not limited to, glycerin, propylene glycol, and mixtures thereof.

In some embodiments, the aerosol-generating substrate comprises at least 35 percent by weight of glycerin, on a dry weight basis. Preferably, the aerosol-generating substrate comprises at least 40 percent by weight of glycerin, on a dry weight basis.

Preferably, the aerosol-generating substrate comprises less than or equal to 75 percent by weight of glycerin, on a dry weight basis. More preferably, the aerosol-generating substrate comprises less than or equal to 70 percent by weight of glycerin, on a dry weight basis. Even more preferably, the aerosol-generating substrate comprises less than or equal to 65 percent by weight of glycerin, on a dry weight basis. In particularly preferred embodiments, the aerosolgenerating substrate comprises less than or equal to 60 percent by weight of glycerin, on a dry weight basis.

In some embodiments, the aerosol-generating substrate comprises from 35 percent by weight to 75 percent by weight of glycerin, on a dry weight basis. Preferably, the aerosolgenerating substrate comprises from 35 percent by weight to 70 percent by weight of glycerin, on a dry weight basis. More preferably, the aerosol-generating substrate comprises from 35 percent by weight to 65 percent by weight of glycerin, on a dry weight basis. Even more preferably, the aerosol-generating substrate comprises from 35 percent by weight to 60 percent by weight of glycerin, on a dry weight basis.

In other embodiments, the aerosol-generating substrate comprises from 40 percent by weight to 75 percent by weight of glycerin, on a dry weight basis. Preferably, the aerosolgenerating substrate comprises from 40 percent by weight to 70 percent by weight of glycerin, on a dry weight basis. More preferably, the aerosol-generating substrate comprises from 40 percent by weight to 65 percent by weight of glycerin, on a dry weight basis. Even more preferably, the aerosol-generating substrate comprises from 40 percent by weight to 60 percent by weight of glycerin, on a dry weight basis.

Preferably, a total combined amount of the tobacco particles and the one or more aerosol formers in the aerosol-generating substrate is at least 95 percent by weight, on a dry weight basis. More preferably, a total combined amount of the tobacco particles and the one or more aerosol formers in the aerosol-generating substrate is at least 96 percent by weight, on a dry weight basis. Even more preferably, a total combined amount of the tobacco particles and the one or more aerosol formers in the aerosol-generating substrate is at least 97 percent by weight, on a dry weight basis.

Thus, the great majority of the aerosol-generating substrate essentially consists of tobacco particles and solvent comprising the one or more aerosols. This maximises the capability of the aerosol-generating element to generate and release aerosol species, and provides for a more efficient use of the volume of the aerosol-generating element compared with certain existing aerosol-generating products. This is also desirable from a viewpoint of overall efficiency and sustainability, in that energy and other resources are actually primarily consumed for providing to the consumer aerosol-generating material, both during manufacturing and during storage and transportation of the aerosol-generating elements.

Preferably, the aerosol-generating substrate comprises less than 5 percent by weight of water. More preferably, the aerosol-generating substrate comprises less than 4 percent by weight of water. Even more preferably, the aerosol-generating substrate comprises less than 3 percent by weight of water. Reducing the consumption of water during the manufacturing process is desirable from a sustainability viewpoint. Additionally, limiting the water content in the aerosol-generating element has the benefit that, during use, only a negligible amount of power is consumed to heat water to and above 100 degrees Celsius - including to provide the latent evaporation heat required to form steam - whilst the majority of the power is used more efficiently to heat the aerosol-generating material.

In some embodiments, a total combined amount of the tobacco particles and the one or more aerosol formers in the aerosol-generating substrate is substantially 100 percent by weight, on a dry weight basis. In other words, the aerosol-generating substrate exclusively contains tobacco particles and aerosol former, preferably exclusively tobacco particles and glycerin.

COMPOSITION OF THE AEROSOL-GENERATING SUBSTRATE - OTHER

In some embodiments, the aerosol-generating substrate further comprises a hydrocolloid.

Including a hydrocolloid in the aerosol-generating substrate has the benefit that mechanical properties of the inner core of the aerosol-generating element may be adjusted, such as by exposing the inner core to divalent cations (for example, Ca⁺⁺ ions in an aqueous solution). Crosslinking of the hydrocolloid may cause some degree of hardening of the inner core, along with some decrease in the elasticity of the inner core. By adjusting the amount of hydrocolloid in the aerosol-generating substrate, the extent of the cross-linking achieved by exposing the inner core to divalent cations can advantageously be fine-tuned.

The aerosol-generating substate may comprise at least 0.5 percent by weight of the hydrocolloid. Preferably, the aerosol-generating substrate comprises at least 1 percent by weight of the hydrocolloid. More preferably, the aerosol-generating substrate comprises at least 1.5 percent by weight of the hydrocolloid. Even more preferably, the aerosol-generating substrate comprises at least 2 percent by weight of the hydrocolloid.

The aerosol-generating substrate preferably comprises less than or equal to 7 percent by weight of the hydrocolloid. More preferably, the aerosol-generating substrate comprises less than or equal to 6 percent by weight of the hydrocolloid. Even more preferably, the aerosol-generating substrate comprises less than or equal to 5 percent by weight of the hydrocolloid.

In some embodiments, the aerosol-generating substrate comprises from 0.5 percent by weight to 7 percent by weight of the hydrocolloid, preferably from 1 percent by weight to 7 percent by weight of the hydrocolloid, even more preferably from 2 percent by weight to 7 percent by weight of the hydrocolloid.

In certain embodiments, the aerosol-generating substrate comprises from 0.5 percent by weight to 6 percent by weight of the hydrocolloid, preferably from 1 percent by weight to 6 percent by weight of the hydrocolloid, even more preferably from 2 percent by weight to 6 percent by weight of the hydrocolloid. In other embodiments, the aerosol-generating substrate comprises from 0.5 percent by weight to 5 percent by weight of the hydrocolloid, preferably from 1 percent by weight to 5 percent by weight of the hydrocolloid, even more preferably from 2 percent by weight to 5 percent by weight of the hydrocolloid.

Preferably, the hydrocolloid is selected from the group consisting of: starch, modified starch, alginate, pectin, cellulose, cellulose derivatives, agar, carrageenan, gelatin, natural gums and combinations thereof.

In preferred embodiments, the hydrocolloid comprises one or more polysaccharides. In particularly preferred embodiments, the hydrocolloid comprises alginate.

In certain embodiments, the hydrocolloid in the aerosol-generating substrate and the film forming polymer in the outer shell comprise the same compound.

This has benefits from a manufacturing viewpoint, in that a single operation can be used to add the hydrocolloid both on the surface of and within the inner core. Further, the cross-linking process induced by exposing the hydrocolloid to divalent cations may strengthen the bond between the outer shell and the more internal portions of the inner core.

In some embodiments, the aerosol-generating substrate further comprises one or more flavourants.

Suitable flavourants for inclusion in an aerosol-generating element in accordance with the present invention would be well known to the skilled person. The flavourant may include one or more natural flavourants, one or more synthetic flavourants, or a combination of natural and synthetic flavourants. Suitable flavourants include, but are not limited to, natural or synthetic menthol, mint flavour such as peppermint flavour or spearmint flavour, coffee flavour, spice flavours (such as cinnamon, clove and ginger), cocoa flavour, vanilla flavour, fruit flavours, chocolate flavour, liquorice flavour, citrus flavour, gamma octalactone, vanillin, ethyl vanillin, breath freshener flavours, methyl salicylate, linalool, bergamot oil, geranium oil, lemon oil, ginger oil, and tobacco flavour, tea flavour, wine flavour, berry flavour, rosemary, star anise, chamomile, sage, lavender, eucalyptus, geranium, eugenol, agave, juniper, anethole and linalool.

In some embodiments, the aerosol-generating substrate further comprises a pH modifier. pH modifiers may be included in aerosol-generating elements in accordance with the present invention with a view to taking advantage of their antioxidant properties. pH modifiers can help maintain the stability of the aerosol-generating substrate and can also act as preservatives.

In certain embodiments, the aerosol-generating substrate further comprises a viscosity modifier. This may help increase the viscosity of the inner core without requiring for the content of tobacco particles to be increased past a certain threshold. Very high contents of tobacco particles may lead to increased viscosity and yet provide only marginal gains from the viewpoint of aerosol delivery, and so it may be preferable to control the viscosity of the inner core without necessarily alter the content of tobacco particles.

OUTER SHELL

The at least one film forming polymer of the outer shell preferably comprises a hydrocolloid, preferably a hydrocolloid selected from the group consisting of: starch, modified starch, alginate, pectin, cellulose, cellulose derivatives, agar, carrageenan, gelatin, natural gums and combinations thereof.

Preferably, the hydrocolloid comprises one or more polysaccharides. More preferably, the one or more polysaccharides comprises alginate. One of the reasons why alginate is a preferred hydrocolloid is its capability of forming networks in the presence of divalent cations, primarily Ca2+ ions.

In some embodiments, the one or more polysaccharides comprises an alginate composite comprising alginate and a further hydrocolloid or a protein or a starch.

Suitable alginate composites comprising alginate and a further hydrocolloid include: alginate-chitosan, alginate-gelatin, alginate pectin, alginate-carrageenan, alginate-guar gum, and alginate-carboxymethyl cellulose (CMC).

Suitable alginate composites comprising alginate and a protein include: alginate-casein, alginate whey-protein, and alginate-soy protein.

Suitable alginate composites comprising alginate and a starch include: alginate-native starch, alginate-resistant starch, and alginate-gelatinised starch. Resistant starches are composed by fractions which are not digested in humans’ small intestine.

Use of alginate composites may be beneficial as these may provide improved protection and controlled release of materials encapsulated within the shell. Without wishing to be bound by theory, it is understood that this may be due to improved physical and mechanical properties of an encapsulating shell obtained when a further hydrocolloid or a protein or a starch is added to alginate. Preferably, the hydrocolloid in the outer shell is cross-linked.

The outer shell may comprise at least 70 percent by weight of the at least one film forming polymer, on a dry weight basis. Preferably, the outer shell comprises at least 80 percent by weight of the at least one film forming polymer, on a dry weight basis. More preferably, the outer shell comprises at least 85 percent by weight of the at least one film forming polymer, on a dry weight basis. Even more preferably, the outer shell comprises at least 90 percent by weight of the at least one film forming polymer, on a dry weight basis. Most preferably, the outer shell comprises at least 95 percent by weight of the at least one film forming polymer, on a dry weight basis.

In some embodiments, the outer shell further comprises a plasticiser. Preferably, the outer shell comprises at least 1 percent by weight of a plasticiser, on a dry weight basis. More preferably, the outer shell comprises at least 2 percent by weight of a plasticiser, on a dry weight basis. Even more preferably, the outer shell comprises at least 3 percent by weight of a plasticiser, on a dry weight basis.

Preferably, the outer shell comprises less than or equal to 6 percent by weight of a plasticiser, on a dry weight basis. More preferably, the outer shell comprises less than or equal to 5 percent by weight of a plasticiser, on a dry weight basis.

The outer shell may have a thickness of at least 60 microns. Preferably, the outer shell has a thickness of at least 80 microns. More preferably, the outer shell has a thickness of at least 100 microns. Even more preferably, the outer shell has a thickness of at least 110 microns. In particularly preferred embodiments, the outer shell has a thickness of at least 120 microns.

The outer shell preferably has a thickness of less than or equal to 2 millimetres. More preferably, the outer shell has a thickness of less than or equal to 1.5 millimetres. Even more preferably, the outer shell has a thickness of less than or equal to 1 millimetre.

An average thickness of the outer shell may correspond to less than or equal to 15 percent of a maximum dimension of the aerosol-generating element.

The expression “maximum dimension of the aerosol-generating element” is used herein to denote the largest dimension of an aerosol-generating element in line with the present disclosure. Depending on the shape of the aerosol-generating element, which will be discussed in more detail below, the term “dimension” may refer to a different geometric parameter of the aerosolgenerating element. For example, for a substantially spherical aerosol-generating element, the maximum dimension corresponds to a diameter of the aerosol-generating element. As another example, for a parallelepiped-shaped aerosol-generating element, the term maximum dimension may refer to the largest one among length, width and thickness of the parallelepiped.

Preferably, an average thickness of the outer shell corresponds to less than or equal to 10 percent of a maximum dimension of the aerosol-generating element. More preferably, an average thickness of the outer shell corresponds to less than or equal to 8 percent of a maximum dimension of the aerosol-generating element. Even more preferably, an average thickness of the outer shell corresponds to less than or equal to 6 percent of a maximum dimension of the aerosolgenerating element.

An average thickness of the outer shell preferably corresponds to at least 1 percent of a maximum dimension of the aerosol-generating element. More preferably, an average thickness of the outer shell preferably corresponds to at least 2 percent of a maximum dimension of the aerosol-generating element. Even more preferably, average thickness of the outer shell preferably corresponds to at least 3 percent of a maximum dimension of the aerosol-generating element.

In some embodiments, an average thickness of the outer shell corresponds to from 1 percent to 10 percent of a maximum dimension of the aerosol-generating element, preferably from 2 percent to 10 percent of a maximum dimension of the aerosol-generating element, more preferably from 3 percent to 10 percent of a maximum dimension of the aerosol-generating element.

In certain embodiments, an average thickness of the outer shell corresponds to from 1 percent to 8 percent of a maximum dimension of the aerosol-generating element, preferably from 2 percent to 8 percent of a maximum dimension of the aerosol-generating element, more preferably from 3 percent to 8 percent of a maximum dimension of the aerosol-generating element.

In some embodiments, an average thickness of the outer shell corresponds to from 1 percent to 6 percent of a maximum dimension of the aerosol-generating element, preferably from 2 percent to 6 percent of a maximum dimension of the aerosol-generating element, more preferably from 3 percent to 6 percent of a maximum dimension of the aerosol-generating element.

A weight of the outer shell may correspond to less than or equal to 50 percent of the weight of the aerosol-generating element. Preferably, a weight of the outer shell corresponds to less than or equal to 45 percent of the weight of the aerosol-generating element. More preferably, a weight of the outer shell corresponds to less than or equal to 40 percent of the weight of the aerosol-generating element. Even more preferably, a weight of the outer shell corresponds to less than or equal to 35 percent of the weight of the aerosol-generating element.

A weight of the outer shell may correspond to at least 1 percent of the weight of the aerosolgenerating element. Preferably, a weight of the outer shell corresponds to at least 2 percent of the weight of the aerosol-generating element. More preferably, a weight of the outer shell corresponds to at least 5 percent of the weight of the aerosol-generating element.

In some embodiments, a weight of the outer shell corresponds to from 1 percent to 45 of the weight of the aerosol-generating element, preferably from 1 percent to 40 percent of the weight of the aerosol-generating element, more preferably from 1 percent to 35 percent of the weight of the aerosol-generating element.

In certain embodiments, a weight of the outer shell corresponds to from 2 percent to 45 of the weight of the aerosol-generating element, preferably from 2 percent to 40 percent of the weight of the aerosol-generating element, more preferably from 2 percent to 35 percent of the weight of the aerosol-generating element.

In other embodiments, a weight of the outer shell corresponds to from 5 percent to 45 of the weight of the aerosol-generating element, preferably from 5 percent to 40 percent of the weight of the aerosol-generating element, more preferably from 5 percent to 35 percent of the weight of the aerosol-generating element.

In some embodiments, the outer shell comprises a combination of two or more different film forming polymers. As discussed above, because the inner core has a paste-like consistency, it is easy to form an aerosol-generating element in accordance with the foregoing description into a variety of different shape. This may be achieved, for example, by introducing a predetermined amount of a formulation comprising the tobacco particles and the liquid solvent comprising one or more aerosol formers into a mould having the shape to be imparted to the aerosol-generating element.

In some preferred embodiments, the aerosol-generating element is substantially spherical.

In other preferred embodiments, the aerosol-generating element is ring shaped (toroidal).

In further notable embodiments, the aerosol-generating element is parallelepiped shaped. One dimension of the parallelepiped may be significantly smaller than the other two dimensions, and so the aerosol-generating element may be substantially in the form of a sheet. The three dimensions of the parallelepiped may be substantially all the same, and so the aerosol-generating element may be substantially cubic.

A maximum dimension of the aerosol-generating element may be at least 0.25 millimetres. Preferably, a maximum dimension of the aerosol-generating element is at least 0.5 millimetres. More preferably, a maximum dimension of the aerosol-generating element is at least 0.75 millimetres. Even more preferably, a maximum dimension of the aerosol-generating element is at least 1 millimetre.

A maximum dimension of the aerosol-generating element may be less than or equal to 5 millimetres. Preferably, a maximum dimension of the aerosol-generating element is less than or equal to 4 millimetres. Even more preferably, a maximum dimension of the aerosol-generating element is less than or equal to 3 millimetres.

In some embodiments, a maximum dimension of the aerosol-generating element is from 0.5 millimetres to 5 millimetres, preferably from 0.75 millimetres to 5 millimetres, more preferably from 1 millimetre to 5 millimetres.

In certain embodiments, a maximum dimension of the aerosol-generating element is from 0.5 millimetres to 4 millimetres, preferably from 0.75 millimetres to 4 millimetres, more preferably from 1 millimetre to 4 millimetres.

In other embodiments, a maximum dimension of the aerosol-generating element is from 0.5 millimetres to 3 millimetres, preferably from 0.75 millimetres to 3 millimetres, more preferably from 1 millimetre to 3 millimetres.

A total weight of the aerosol-generating element may be at least 0.05 grams. Preferably, a total weight of the aerosol-generating element is at least 0.1 grams. More preferably, a total weight of the aerosol-generating element is at least 0.25 grams. Even more preferably, a total weight of the aerosol-generating element is at least 0.5 grams.

A total weight of the aerosol-generating element may be less than or equal to 1 .5 grams. Preferably, a total weight of the aerosol-generating element is less than or equal to 1 .25 grams. More preferably, a total weight of the aerosol-generating element is less than or equal to 1 gram. Even more preferably, a total weight of the aerosol-generating element is less than or equal to 0.8 grams.

In some embodiments, a total weight of the aerosol-generating element is from 0.1 grams to 1.5 grams, preferably from 0.1 grams to 1.25 grams, more preferably from 0.1 grams to 1 gram, even more preferably from 0.1 grams to 0.8 grams.

In certain embodiments, a total weight of the aerosol-generating element is from 0.25 grams to 1.5 grams, preferably from 0.25 grams to 1.25 grams, more preferably from 0.25 grams to 1 gram, even more preferably from 0.25 grams to 0.8 grams.

In other embodiments, a total weight of the aerosol-generating element is from 0.5 grams to 1.5 grams, preferably from 0.5 grams to 1 .25 grams, more preferably from 0.5 grams to 1 gram, even more preferably from 0.5 grams to 0.8 grams.

A total water content of the aerosol-generating element may be less than 5 percent. Preferably, a total water content of the aerosol-generating element is less than 4 percent. More preferably, a total water content of the aerosol-generating element is less than 3 percent. Even more preferably, a total water content of the aerosol-generating element is less than 2.5 percent. In particularly preferred embodiments, a total water content of the aerosol-generating element is less than 2 percent.

Similarly low water contents make it possible for the manufacturing process to be more sustainable as the overall consumption of natural resources is advantageously minimised.

As described briefly above, an aerosol-generating element in line with the foregoing description may be used on its own with an aerosol-generating device adapted to supply heat to the aerosol-generating substrate contained in the aerosol-generating element to generate an inhalable aerosol that can be delivered to a consumer. In particular, the aerosol-generating device is preferably an electrically operated aerosol-generating device that comprises a heater element configured to heat the aerosol-generating element.

However, one or more aerosol-generating elements as described above may also be included in an aerosol-generating article for use with an aerosol-generating device. The aerosolgenerating device is preferably an electrically operated aerosol-generating device that comprises a heater element configured to heat the aerosol-generating article.

The present disclosure also relates to a method for the production of an aerosol-generating element as described above.

The method may comprise a step of forming a core composition comprising tobacco particles and one or more aerosol formers.

The method may further comprise a step of forming a discrete portion of the core composition to provide an inner core.

The method may additionally comprise a step of coating the inner core with a coating composition comprising at least one film forming polymer. The method may also comprise a step of drying the coated inner core to form an aerosolgenerating element having an inner core and an outer shell.

According to a third aspect of the present invention, there is provided a method for the production of an aerosol-generating element according to the first aspect of the present invention, the method comprising the steps of: forming a core composition comprising tobacco particles and one or more aerosol formers; forming a discrete portion of the core composition to provide an inner core; coating the inner core with a coating composition comprising at least one film forming polymer; and drying the coated inner core to form an aerosol-generating element having an inner core and an outer shell.

Advantageously, because of the paste-like consistency of the core composition, in the step of forming a discrete portion of the core composition it is possible to adjust and control the size and shape of the inner core. The inner core then easily maintains the shape and size imparted to it during the forming step, and in the subsequent step of coating the inner core the coating composition comprising the film forming polymer can be used to encapsulate the inner core. This may further stabilise the size and shape of the inner core and, more generally, of the aerosolgenerating element as a whole.

Preferably, the method further comprises a step of adding the coated inner core to a crosslinking solution of multivalent cations to cross-link the film forming polymer, prior to the drying step. This enables the manufacture of aerosol-generating element wherein a stronger bond may be established between the outer shell and the inner core.

In some embodiments, the core composition further comprises a hydrocolloid.

Preferably, the method further comprises a step of adding the discrete portion of the core composition to a cross-linking solution of multivalent cations prior to the coating step. The crosslinking reaction between the hydrocolloid and the multivalent cations advantageously provides for the hardening and generally strengthening of the outer shell and, in broader terms, of the aerosolgenerating element as a whole. In those embodiments wherein a (same) hydrocolloid is present in the core composition and in the coating composition, a particularly strong bond may be established between the inner core and the outer shell, which may impart the aerosol-generating element particularly desirable structural strength.

Preferably, the core composition comprises less than 5 percent by weight of water. More preferably, the core composition comprises substantially no water. This has the benefit of making the overall manufacturing process especially sustainable.

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

Example Ex1 : An aerosol-generating element for use in an aerosol-generating article or system, the aerosol-generating element comprising: an inner core of an aerosol-generating substrate, the aerosol-generating substrate comprising tobacco particles and a liquid solvent comprising one or more aerosol formers; and an outer shell encapsulating the inner core of aerosol-generating substrate, the outer coating comprising at least one film-forming polymer, wherein the aerosol-generating substrate comprises at least 20 percent by weight of tobacco particles and at least 30 percent by weight of the one or more aerosol formers, on a dry weight basis.

Example Ex2: An aerosol-generating element according to example Ex1 , wherein a weight ratio of tobacco particles to liquid solvent in the aerosol-generating substrate is at least 0.3.

Example Ex3: An aerosol-generating element according to example Ex1 or Ex2, wherein the viscosity of the aerosol-generating substrate is less than 20,000 cp.

Example Ex4: An aerosol-generating element according to any one of examples Ex1 to Ex3, wherein the viscosity of the aerosol-generating substrate is at least 6,000 cp.

Example Ex5: An aerosol-generating element according to any preceding example, wherein a weight ratio of tobacco particles to liquid solvent in the aerosol-generating substrate is less than 1.5.

Example Ex6: An aerosol-generating element according to any preceding example, wherein the aerosol-generating substrate is an aerosol-generating suspension of the tobacco particles in the liquid solvent.

Example Ex7: An aerosol-generating element according to any preceding example, wherein a density of the aerosol-generating substrate is at least 1 gram per cubic centimetre.

Example Ex8: An aerosol-generating element according to any preceding example, wherein a density of the aerosol-generating substrate is less than 2 grams per cubic centimetre.

Example Ex9: An aerosol-generating element according to any preceding example, wherein the aerosol-generating substrate comprise at least 35 percent by weight of tobacco particles, on a dry weight basis.

Example Ex10: An aerosol-generating element according to any preceding example, wherein the aerosol-generating substrate comprises less than 65 percent by weight of tobacco particles, on a dry weight basis.

Example Ex11 : An aerosol-generating element according to any preceding example, wherein the tobacco particles have an average particle size of at least 30 microns.

Example Ex12: An aerosol-generating element according to any preceding example, wherein the tobacco particles have a D90 value of less than 120 microns.

Example Ex13: An aerosol-generating element according to any preceding example, wherein the tobacco particles have a D90 value of between 50 microns and 70 microns.

Example Ex14: An aerosol-generating element according to any preceding example, wherein the tobacco particles are substantially homogeneously distributed through the aerosolgenerating substrate. Example Ex15: An aerosol-generating element according to any preceding example, wherein the aerosol-generating substrate comprises at least 40 percent by weight of the one or more aerosol formers, on a dry weight basis.

Example Ex16: An aerosol-generating element according to any preceding example, wherein the aerosol-generating substrate comprises less than 60 percent by weight of the one or more aerosol formers, on a dry weight basis.

Example Ex17: An aerosol-generating element according to any preceding example, wherein the aerosol-generating substrate comprises at least 40 percent by weight of glycerin, on a dry weight basis.

Example Ex18: An aerosol-generating element according to any preceding example, wherein a total combined amount of the tobacco particles and the one or more aerosol formers in the aerosol-generating substrate is at least 95 percent by weight, on a dry weight basis.

Example Ex19: An aerosol-generating element according to any preceding example, wherein the aerosol-generating substrate comprises less than 5 percent by weight of water.

Example Ex20: An aerosol-generating element according to any preceding example, wherein the aerosol-generating substrate further comprises a hydrocolloid.

Example Ex21 : An aerosol-generating element according to example Ex20, wherein the aerosol-generating substrate comprises at least 1 percent by weight of the hydrocolloid.

Example Ex22: An aerosol-generating element according to example Ex20 or Ex21 , wherein the aerosol-generating substrate comprises less than 5 percent by weight of the hydrocolloid.

Example Ex23: An aerosol-generating element according to any one of examples Ex20 to Ex22, wherein the hydrocolloid is selected from the group consisting of: starch, modified starch, alginate, pectin, cellulose, cellulose derivatives, agar, carrageenan, gelatin, natural gums and combinations thereof.

Example Ex24: An aerosol-generating element according to any one of examples Ex20 to Ex23, wherein the hydrocolloid comprises one or more polysaccharides.

Example Ex25: An aerosol-generating element according to example Ex23 or Ex24, wherein the hydrocolloid comprises alginate.

Example Ex26: An aerosol-generating element according to any one of examples Ex20 to Ex25, wherein the hydrocolloid in the aerosol-generating substrate and the film forming polymer in the outer shell comprise the same compound.

Example Ex27: An aerosol-generating element according to any preceding example, wherein the aerosol-generating substrate further comprises one or more flavourants.

Example Ex28: An aerosol-generating element according to any preceding example, wherein the at least one film forming polymer of the outer shell comprises a hydrocolloid. Example Ex29: An aerosol-generating element according to example Ex28, wherein the hydrocolloid is selected from the group consisting of: starch, modified starch, alginate, pectin, cellulose, cellulose derivatives, agar, carrageenan, gelatin, natural gums and combinations thereof.

Example Ex30: An aerosol-generating element according to example Ex28 of Ex29, wherein the hydrocolloid comprises one or more [cross-linked] polysaccharides.

Example Ex31 : An aerosol-generating element according to example Ex30, wherein the one or more [cross-linked] polysaccharides comprises alginate.

Example Ex32: An aerosol-generating element according to any preceding example, wherein the outer shell comprises at least 80 percent by weight of the at least one film forming polymer, on a dry weight basis.

Example Ex33: An aerosol-generating element according to example Ex32, wherein the outer shell comprises at least 90 percent by weight of the at least one film forming polymer, on a dry weight basis.

Example Ex34: An aerosol-generating element according to any preceding example, wherein the outer shell further comprises a plasticiser.

Example Ex35: An aerosol-generating element according to example Ex34, wherein the outer shell comprises at least 2 percent by weight of a plasticiser, on a dry weight basis.

Example Ex36: An aerosol-generating element according to any preceding example, wherein the outer shall has an average thickness of at least 100 microns.

Example Ex37: An aerosol-generating element according to any preceding example, wherein the outer shell has an average thickness of less than 2 millimetres.

Example Ex38: An aerosol-generating element according to any preceding example, wherein an average thickness of the outer shell corresponds to less than 10 percent of the maximum dimension of the aerosol-generating element.

Example Ex39: An aerosol-generating element according to any preceding example, wherein a weight of the outer shell corresponds to less than 10 percent of the weight of the aerosol-generating element.

Example Ex40: An aerosol-generating element according to any preceding example, wherein the outer shell comprises a combination of two or more different film forming polymers.

Example Ex41 : An aerosol-generating element according to any preceding example, wherein a maximum dimension of the aerosol-generating element is at least 0.5 millimetres.

Example Ex42: An aerosol-generating element according to any preceding example, wherein a maximum dimension of the aerosol-generating element is at least 1 millimetre.

Example Ex43: An aerosol-generating element according to any preceding example, wherein a maximum dimension of the aerosol-generating element is less than 3 millimetres. Example Ex44: An aerosol-generating element according to any preceding example, wherein a total weight of the aerosol-generating element is at least 0.1 grams.

Example Ex45: An aerosol-generating element according to any preceding example, wherein a total weight of the aerosol-generating element is less than 1 gram.

Example Ex46: An aerosol-generating element according to any preceding example, wherein a total water content of the aerosol-generating element is less than 5 percent.

Example Ex47: An aerosol-generating element according to any preceding example, wherein the aerosol-generating element is substantially spherical.

Example Ex48: An aerosol-generating element according to any preceding example, wherein the aerosol-generating element is ring shaped.

Example Ex49: An aerosol-generating element according to any preceding example, wherein the aerosol-generating element is in the form of a sheet.

Example Ex50: An aerosol-generating article comprising an aerosol-generating element according to any preceding example.

Example Ex51 : An aerosol-generating system comprising an aerosol-generating element according to any one of Examples Ex1 to Ex49 and an electrically operated aerosol-generating device comprising a heater element configured to heat the aerosol-generating element.

Example Ex52: A method for production of the aerosol-generating element according to any one of Examples Ex1 to Ex49, the method comprising the steps of: forming a core composition comprising tobacco particles and one or more aerosol formers; forming a discrete portion of the core composition to provide an inner core; coating the inner core with a coating composition comprising at least one film forming polymer; and drying the coated inner core to form an aerosol-generating element having an inner core and an outer shell.

Example Ex53: A method according to example Ex52, further comprising the step of adding the coated inner core to a cross-linking solution of multivalent cations to cross-link the film forming polymer, prior to the drying step.

Example Ex54: A method according to example Ex52 or Ex53, wherein the core composition further comprises a hydrocolloid.

Example Ex55: A method according to example Ex54, further comprising the step of adding the discrete portion of the core composition to a cross-linking solution of multivalent cations prior to the coating step.

Example Ex56: A method according to example Ex52, wherein the core composition comprises less than 5 percent by weight of water.

Example Ex57: A method according to example Ex56, wherein the core composition comprises substantially no water. Examples will now be further described with reference to the figures in which:

Figure 1 shows a schematic side view of an aerosol-generating element according to the present invention;

Figure 2 shows a schematic cross-sectional view of the aerosol-generating element of Figure 1 ;

Figure 3 is a photograph is the aerosol-generating element illustrated schematically in Figures 1 and 2;

Figure 4 shows a schematic side view of another aerosol-generating element according to the present invention;

Figure 5 shows a schematic side view of a further aerosol-generating element according to the present invention;

Figure 6 a schematic perspective view of yet another aerosol-generating element according to the present invention.

An aerosol-generating element 10 in accordance with the present invention is illustrated schematically in Figure 1. The aerosol-generating element 10 is substantially spherical and has a maximum dimension DMAX, which corresponds to a diameter of the aerosol-generating element 10, of 10.8 millimetres.

As shown in Figure 2, the aerosol-generating element comprises an inner core 12 of an aerosol-generating substrate and an outer shell 14 encapsulating the inner core 12 of aerosolgenerating substrate.

The aerosol-generating substrate comprises tobacco particles and a liquid solvent comprising glycerin.

In more detail, the inner core is formed from a paste prepared by mixing 17 grams of tobacco particles with 20 grams of glycerin, the inner core being shaped with a mould and then dipped into a 2wt% alginate aqueous solution. The inner core having an alginate coating is dipped into a 2wt% calcium lactate solution for a few seconds, which causes almost immediately the alginate coating to solidify around the inner core, thus forming an outer shell encapsulating the inner core.

A thickness of the outer shell 14 is 0.8 millimetres, that is 7.4 percent of the maximum dimension DMAX.

The structure of the aerosol-generating element of Figures 1 and 2 is also shown in the photograph of Figure 3. Both the inner core and the outer shell can be easily identified.

Figures 4, 5, and 6 illustrated other examples of aerosol-generating elements in accordance with the present invention. The inner cores and outer shells of the aerosol-generating elements 20, 30, and 40 of Figures 4, 5, and 6 have the same composition of the inner core 12 and outer shell 14 of the aerosol-generating element 10 of Figures 1 , 2, and 3. However, the aerosolgenerating elements 20, 30, and 40 differ from the aerosol-generating element 10 in that they have different shapes and, accordingly, different maximum dimensions DMAX. The aerosol-generating element 20 of Figure 4 has an elongate, pill shape and its maximum dimension DMAX corresponds to a length of the aerosol-generating element 20 measured along the longitudinal axis of the aerosol-generating element 20.

The aerosol-generating element 30 of Figure 5 has a toroidal shape, and its maximum dimension DMAX corresponds to an outer diameter of the aerosol-generating element 30.

The aerosol-generating element 40 of Figure 6 has parallelepiped shape and its maximum dimension DMAX corresponds to a width of the aerosol-generating element 40, since in the parallelepiped illustrated in Figure 6 depth and height are smaller than the width.

In another example, the inner core is formed from a paste prepared by mixing 10 grams of tobacco particles with 20 grams of glycerin and 40 grams of a 2wt% alginate aqueous solution, the inner core being shaped with a mould and then dipped into a 2wt% calcium lactate solution for a few seconds. The resulting inner core is subsequently dipped into the 2wt% alginate aqueous solution for another few seconds and then once again dipped into a 2wt% calcium lactate solution for a few seconds. This causes almost immediately the formation of a solid alginate coating around the inner core, thus forming an outer shell encapsulating the inner core. In the previous dipping steps, at least part of the alginate contained within the inner core also reacts with the calcium cations, and so a bond is established between the inner core and the outer shell.

For the purpose of the present description and of the appended claims, except where otherwise indicated, all numbers expressing amounts, quantities, percentages, and so forth, are to be understood as being modified in all instances by the term "about". Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein. In this context, therefore, a number A is understood as A ± 10 percent of A. Within this context, a number A may be considered to include numerical values that are within general standard error for the measurement of the property that the number A modifies. The number A, in some instances as used in the appended claims, may deviate by the percentages enumerated above provided that the amount by which A deviates does not materially affect the basic and novel characteristic(s) of the claimed invention. Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein.

Claims

1. An aerosol-generating element for use in an aerosol-generating article or system, the aerosol-generating element comprising: an inner core of an aerosol-generating substrate, the aerosol-generating substrate comprising tobacco particles and a liquid solvent comprising one or more aerosol formers; and an outer shell encapsulating the inner core of aerosol-generating substrate, the outer coating comprising at least one film-forming polymer, wherein the aerosol-generating substrate comprises at least 20 percent by weight of tobacco particles and at least 30 percent by weight of the one or more aerosol formers, on a dry weight basis, wherein a weight ratio of tobacco particles to liquid solvent in the aerosol-generating substrate is at least 0.3.

2. An aerosol-generating element according to any preceding claim, wherein a weight ratio of tobacco particles to liquid solvent in the aerosol-generating substrate is less than 1.5.

3. An aerosol-generating element according to any preceding claim, wherein the aerosolgenerating substrate is an aerosol-generating suspension of the tobacco particles in the liquid solvent.

4. An aerosol-generating element according to any preceding claim, wherein a density of the aerosol-generating substrate is at least 1 gram per cubic centimetre.

5. An aerosol-generating element according to any preceding claim, wherein a density of the aerosol-generating substrate is less than 2 grams per cubic centimetre.

6. An aerosol-generating element according to any preceding claim, wherein the aerosolgenerating substrate comprise at least 35 percent by weight of tobacco particles, on a dry weight basis.

7. An aerosol-generating element according to any preceding claim, wherein the aerosolgenerating substrate comprises less than 65 percent by weight of tobacco particles, on a dry weight basis.

8. An aerosol-generating element according to any preceding claim, wherein the tobacco particles have a D90 value of less than 120 microns.

9. An aerosol-generating element according to any preceding claim, wherein the aerosolgenerating substrate comprises at least 40 percent by weight of the one or more aerosol formers, on a dry weight basis.

10. An aerosol-generating element according to any preceding claim, wherein a total combined amount of the tobacco particles and the one or more aerosol formers in the aerosolgenerating substrate is at least 95 percent by weight, on a dry weight basis.

11. An aerosol-generating element according to any preceding claim, wherein the at least one film forming polymer of the outer shell comprises a hydrocolloid.

12. An aerosol-generating article comprising an aerosol-generating element according to any preceding claim.

13. An aerosol-generating system comprising an aerosol-generating element according to any of claims 1 to 11 and an electrically operated aerosol-generating device comprising a heater element configured to heat the aerosol-generating element.

14. A method for production of the aerosol-generating element according to any of claims 1 to 11 , the method comprising the steps of: forming a core composition comprising tobacco particles and one or more aerosol formers; forming a discrete portion of the core composition to provide an inner core; coating the inner core with a coating composition comprising at least one film forming polymer; and drying the coated inner core to form an aerosol-generating element having an inner core and an outer shell.

15. A method according to claim 14, further comprising the step of adding the coated inner core to a cross-linking solution of multivalent cations to cross-link the film forming polymer, prior to the drying step.