Aerosol generating segment

Abstract

An aerosol-generating segment 100 for a heat-not-burn consumable, the aerosol-generating segment 100 comprising an aerosol forming material 6 which comprises a substrate 120 and aerosol former, where the aerosol former is non-uniformly distributed in the substrate 120 and is at a higher average concentration in a central region 122 than a peripheral region 124; a heat-not-burn consumable 70 comprising such an aerosol-generating segment 100; an aerosol-generating system comprising such an aerosol-generating segment 100, or such a heat-not-burn consumable 70 and an aerosol-generating unit 1; a method of manufacturing such an aerosol-generating segment 100; and use of the same.

Description

FIELD

[0001] The present disclosure relates to an aerosol-generating segment for use in an aerosol-generating apparatus. The aerosol-generating segment comprises a central region with a higher average concentration of aerosol former than a peripheral region. The present disclosure also relates to a heat-not-burn (HNB) consumable comprising said aerosol-generating segment; an aerosol-generating apparatus comprising said aerosol-generating segment or said HNB consumable; a kit comprising said aerosol-generating segment or said HNB consumable and an aerosol-generating apparatus; methods of manufacturing said aerosol-generating segment; and uses of a higher average aerosol former concentration in the central region of said aerosol-generating segments than in the peripheral region.BACKGROUND

[0002] A typical aerosol generating consumable comprises an aerosol generating segment. The aerosol generating consumable is typically used in an aerosol generating apparatus. A typical aerosol generating apparatus may comprise a power supply, an aerosol generating unit that is driven by the power supply, an aerosol forming material, which in use is aerosolised by the aerosol generating unit to generate an aerosol, and a delivery system for delivery of the aerosol to a user. The aerosol forming material may be contained within the aerosol generating consumable.

[0003] A drawback with known aerosol generating segments, especially those comprising large amounts of aerosol former, is that the aerosol former can migrate or leak out of the aerosol generating segment. Migration of aerosol former into neighbouring segments may cause the neighbouring segments or surrounding materials to become damp and / or affect mechanical properties of the consumable and / or affect the tactile sensation for the user (sticky feeling). Leaking of aerosol former out around the seams or ends of the consumable may impact the aesthetics and / or the shelf life and / or consistency during production.

[0004] It is against this background that the present invention has been developed.SUMMARY

[0005] In general, the present disclosure provides an aerosol-generating segment where the concentration of aerosol former is greater at a central region than a peripheral region of the segment. In other words, the concentration of aerosol former adjacent a wrapper is lower than in the centre of the segment (away from the wrapper).

[0006] In a general aspect the present disclosure provides an aerosol-generating segment for a heat-not-burn consumable, the aerosol-generating segment wherein an aerosol former is non-uniformly distributed in the substrate, such that there is a first average concentration of aerosol former in a central region of the substrate and a second average concentration of aerosol former in a peripheral region of the substrate, wherein the first average concentration is higher than the second average concentration.

[0007] In a first aspect the present disclosure provides an aerosol-generating segment for a heat-not-burn consumable, the aerosol-generating segment comprising: an aerosol forming material, comprising a substrate and an aerosol former; and a wrapper circumscribing the aerosol forming material; wherein the aerosol former is non-uniformly distributed in the substrate, such that there is a first average concentration of aerosol former in a central region of the substrate and a second average concentration of aerosol former in a peripheral region of the substrate, wherein the first average concentration is higher than the second average concentration.

[0008] The aerosol-generating segment of the present invention is for use in a heat-not-burn (HNB) aerosol-generating device. The aerosol-generating segment is for use in a heat-not-burn (HNB) consumable, which in some examples comprises further segments, for example cooling segments, filter segments, or further aerosol-generating segments.

[0009] The aerosol-generating segment comprises an aerosol forming material which comprises a substrate which is capable of generating an aerosol when heated with an aerosol former. A wrapper wraps the aerosol forming material and defines the perimeter of the aerosol-generating segment. In some examples, the wrapper is a paper wrapper or paper-based wrapper. In some examples, the wrapper surrounds a portion of the aerosol forming material (i.e. it incompletely wraps the aerosol forming material). In some examples, the same wrapper wraps more than one aerosol-generating segment together, for example in a heat-not-burn consumable comprising more than one aerosol-generating segment, as described below.

[0010] The aerosol-forming material may be circumscribed by a wrapping layer e.g. a paper wrapping layer. The wrapping layer may overlie an inner foil layer or may comprise a paper / foil laminate (with the foil innermost).

[0011] Any elements (e.g. filter elements, cooling element, spacer elements) downstream of the aerosol-forming material may be at least partially (e.g. entirely) circumscribed by the wrapping layer. Accordingly, the wrapping layer may alternatively be referred to as a 'combining layer'. The wrapping layer may at least partially (e.g. entirely) circumscribe elements upstream of the terminal filter element.

[0012] The terminal filter element (at the downstream end of the article / consumable) may be joined to the upstream elements forming the article / consumable by a circumscribing tipping layer e.g. a tipping paper layer. The tipping paper may have an axial length longer than the axial length of the terminal filter element such that the tipping paper completely circumscribes the terminal filter element plus the wrapping layer surrounding any adjacent upstream element.

[0013] Any elements (e.g. filter elements, cooling element, spacer elements) may be further circumscribed by a respective plug wrap e.g. a paper plug wrap.

[0014] In some examples, the substrate takes up 50% or more of the volume of the aerosol-generating segment, wherein the total volume of the aerosol-generating segment is 100%. In some examples, the substrate takes up 60% or more of the volume of the aerosol-generating segment, such as 70% or more, 80% or more, 90% or more, or 95% or more of the volume of the aerosol-generating segment. In some examples, the substrate takes up substantially all of the volume of the aerosol-generating segment.

[0015] In some examples, the shape formed by the substrate within the aerosol-generating segment is approximately the same shape as the aerosol-generating segment. In some examples, the length of the substrate in the aerosol forming material is the same or substantially the same as that of the aerosol-generating segment, for example when both the aerosol-generating segment and the substrate are elongate. In some examples, the shape of the aerosol-generating segment is defined by the wrapper. Herein, the combination of substrate and aerosol former, possibly including further components, make up the aerosol forming material ("precursor").

[0016] The aerosol former is non-uniformly distributed in the substrate. In some examples, the aerosol former is held within pores of the substrate and can be described as being impregnated within the substrate. In some examples, the aerosol former is coated on constituent particles (e.g. fibres, beads, flakes, etc) of the substrate. In some examples, the aerosol former is located between constituent particles (e.g. fibres, beads, flakes, etc) of the substrate. The aerosol former, being non-uniformly distributed in the substrate, is also non-uniformly distributed in the aerosol forming material.

[0017] Herein, a uniform distribution is understood to mean a substantially uniform distribution. In such distributions, the aerosol former may be present at substantially the same average concentration across the entirety of the substrate. A uniform distribution is capable of having localised fluctuations in concentration, but globally comprises no significant maxima or minima in average concentration. Herein, "uniform" might also be described as being "constant" or "substantially constant".

[0018] In contrast, a non-uniform distribution features at least one global maximum and minimum concentration. In some examples the non-uniform distribution comprises one maximum in average aerosol former concentration. In some examples the non-uniform distribution comprises more than one, for example 2, 3, 4, 5, 6, 7, 8, 9 or 10 global maxima in aerosol former average concentration. In some examples the non-uniform distribution comprises one global minimum. In some examples, the non-uniform distribution comprises more than one, for example 2, 3, 4, 5, 6, 7, 8, 9 or 10 global minima in aerosol former average concentration.

[0019] There is a first average concentration of aerosol former in a central region of the substrate, and a second average concentration of aerosol former in a peripheral region of the substrate, wherein the first average concentration is higher than the second average concentration. That is, there is a higher average concentration of aerosol former in a central region of the substrate compared to a peripheral region of the substrate.

[0020] A central region of the substrate is a portion of substrate located approximately centrally in the substrate. In some examples the central region is characterised by being spaced from one or more of the outer edges (e.g. all of the outer edges) or the periphery (e.g. the entire periphery) of the substrate in the aerosol generating segment. The central region takes up a non-zero amount of the volume of the substrate. The central region does not take up all of the volume of the substrate (i.e. there exists a peripheral region).

[0021] In some examples, the central region takes up ≥ 1%, ≥ 2%, ≥ 3%, ≥ 4%, ≥ 5%, ≥ 10%, ≥ 20%, or ≥ 30% of the total volume of the substrate, wherein the total volume of the substrate is 100%. In some examples, the central region takes up ≤ 10%, ≤ 15%, ≤ 20%, ≤ 25%, ≤ 30%, ≤ 35%, ≤ 40%, ≤ 45%, ≤ 50%, ≤ 55%, ≤ 60%, ≤ 65%, ≤ 70%, ≤ 75%, ≤ 80%, ≤ 85%, ≤ 90%, or ≤ 95% of the total volume of the substrate. All of the foregoing ranges can be combined freely to generate a range bound by a minimum and a maximum (for example, ≥ 50% and ≤ 60%).

[0022] In some examples, the central region takes up ≥ 1% and ≤ 95% of the volume of the substrate. In some examples, the central region takes up ≥ 10% and ≤ 90%, ≥ 20% and ≤ 80%, ≥ 30% and ≤ 70%, ≥ 40% and ≤ 60% or about 50% of the volume of the substrate. In some examples, whatever % of the volume of the substrate is taken up by the central region, the peripheral region is included in the remaining volume.

[0023] A peripheral region of the substrate has a second average concentration of aerosol former that is lower than a first average concentration of aerosol former in a central region. That is, a peripheral region of the substrate comprises a lower average concentration of aerosol former than a central region. In some examples, the peripheral region is defined as being close to or adjacent to one or more of the outer edges (e.g. all of the outer edges) or the periphery (e.g. the entire periphery) of the volume taken up by the substrate. In some examples, the peripheral region is in contact with one or more outer edges or the periphery of the volume taken up by the substrate. In some examples the peripheral region is in contact with the wrapper which defines the outer edge or the periphery of the aerosol-generating segment. The peripheral region does not take up all of the volume of the substrate (i.e. there exists a central region).

[0024] In some examples, the peripheral region takes up ≥ 1%, ≥ 2%, ≥ 3%, ≥ 4%, ≥ 5%, ≥ 10%, ≥ 20%, or ≥ 30% of the volume of the substrate, wherein the total volume of the substrate is 100%. In some examples, the peripheral region takes up ≤ 10%, ≤ 15%, ≤ 20%, ≤ 25%, ≤ 30%, ≤ 35%, ≤ 40%, ≤ 45%, ≤ 50%, ≤ 55%, ≤ 60%, ≤ 65%, ≤ 70%, ≤ 75%, ≤ 80%, ≤ 85%, ≤ 90%, or ≤ 95% of the total volume of the substrate. All of the foregoing values can be combined freely to generate a range bound by a minimum and a maximum (for example, ≥ 50% and ≤ 60%).

[0025] In some examples, the peripheral region takes up ≥ 1% and ≤ 95% of the volume of the substrate. In some examples, the peripheral region takes up ≥ 10% and ≤ 90%, ≥ 20% and ≤ 80%, ≥ 30% and ≤ 70%, ≥ 40% and ≤ 60%, or about 50% of the volume of the substrate. In some examples, whatever % of the volume of the substrate is taken up by the peripheral region, the central region is included in the remaining volume.

[0026] In some examples, the peripheral region completely surrounds the central region. In some examples, the peripheral region surrounds 50% or more, 60% or more, 70% or more, 80% or more, 90% or more, 95% or more, or 100% of the central region.

[0027] In some examples, the central region has a non-uniform or non-regular shape. In some examples, the central region can be offset from, or spaced apart from, the central point of the substrate, whilst still being a central region according to the present invention. In some examples, the central region does not encompass the central point of the substrate. In some examples, ≥ 50%, ≥ 60%, ≥ 70%, ≥ 80%, ≥ 90% or substantially all or all of the central region is contained in one half of the substrate.

[0028] In some examples, a cross-section of the central region has a non-uniform, or non-regular shape. In some examples, the cross section of the central region varies along its length and as such the central region can have a non-uniform or non-constant cross-section along its length. In some examples, the cross-section of the central region is a single shape, in such a case the cross section may be substantially the same size at all points in the central region, or the cross-section may vary in size. In some examples, the cross section is circular, triangular, rectangular, pentagonal, hexagonal or any other regular or irregular two-dimensional shape.

[0029] Average concentration as used herein refers to a spatially averaged concentration. Such a value can be obtained by sampling a portion of substrate and measuring the amount of aerosol former (for example, in g), measuring the volume of substrate sampled, and then calculating the volume average mass (= g / mm 3< ). The concentration may be measured by sampling the aerosol former every 0.5 mm or every 1 mm, or every 2 mm along the length of the substrate. The volume of substrate used in such a calculation should be small enough to obtain a meaningfully localised value of average concentration, and should be located such that it can be confirmed that a central region comprises a higher average concentration than a peripheral region. For example, it would be satisfactory to take such a measurement for the entire central region, as compared to the entire peripheral region. However, it might also be satisfactory to take a number of small samples from the central and peripheral regions in order to arrive at an average concentration.

[0030] The average concentration of aerosol former in a central region of the substrate is higher than in a peripheral region of the substrate. In some examples, the average concentration of aerosol former in the central region is at least 10%, at least 25%, at least 50%, at least 100%, at least 200%, or at least 300% higher than in a peripheral region. In some examples, the average concentration of aerosol former in the central region is from 10 to 1000% higher than in a peripheral region, such as 20 to 500%, 30 to 200%, 40 to 100%, 50 to 90%, 70 to 80% higher than in a peripheral region.

[0031] In some examples, the average concentration of aerosol former in the central region is 20 wt.% or more, 35 wt.% or more, 40 wt.% or more, 45 wt.% or more, 50 wt.% or more. In some examples, the average concentration of aerosol former in the central region is in the range of from 20 to 50 wt.%, such as from 25 to 40 wt.%, from 30 to 35 wt.%.

[0032] In some examples the average concentration of aerosol former in the peripheral region is 30 wt.% or less, 25 wt.% or less, 20 wt.% or less, 15 wt.% or less, 10 wt.% or less or 5 wt.% or less. In some examples the average concentration of aerosol former in the peripheral region is from 1 to 25 wt.%, such as from 2 to 20 wt.%, from 3 to 15 wt.%, from 4 to 10 wt.%, or about 5 wt.%.

[0033] In aerosol-generating segments containing aerosol former (e.g. propylene glycol or glycerol, such as vegetable glycerin), particularly when there are large amounts of aerosol former, the aerosol former can migrate to different areas of the aerosol-generating segments, affecting the user perception, mechanical properties and shelf life of the segment, and a consumable in which it is comprised. In some examples, by providing a substrate which comprises a higher average concentration of aerosol former in a central region as compared to a peripheral region of the substrate, migration of the aerosol former to problematic locations in a consumable containing the aerosol-generating segment may be reduced, minimised or eliminated (for example, the wrapper or adjacent segments). In some examples, shelf-life, structural integrity, performance and user experience may be improved. Without wishing to be bound by theory, it is thought that in the present invention, migration at least takes a longer to occur, and it is thought that migration may be prevented all together. In some examples, an additional benefit of reducing aerosol former migration, may be that higher levels of aerosol former can be used in a central region without migration occurring, or at least without migration occurring to a level at which user perception, mechanical properties and shelf-life are affected.

[0034] In some examples, the aerosol-generating segment further comprises one or more of a carrier, an active ingredient, and a flavouring.

[0035] In some examples of the aerosol-generating segment, the aerosol-generating segment and the substrate are elongate.

[0036] In some examples, the aerosol-generating segment is prolate, or rod-shaped, or has a prismatic shape, or has a cylindrical shape. In some examples, the aerosol forming material is prolate, or rod-shaped, or has a cylindrical shape. In some examples, the substrate is prolate, or rod-shaped, or has a prismatic shape, or has a cylindrical shape.

[0037] The elongate length of the aerosol-generating segment, the aerosol forming material and the substrate defines a longitudinal axis. Perpendicular to this axis is a radial direction.

[0038] In some examples the aerosol generating segment has a length of 1 to 50 mm. In some examples the length of the aerosol generating segment is 5 to 30 mm. In some examples the aerosol generating segment has a thickness (e.g. diameter) of 1 to 15 mm. In some examples the thickness of the aerosol generating segment is 4 to 12 mm. In some examples, the elongate substrate is continuous or unbroken / uninterrupted.

[0039] In some examples of the aerosol-generating segment, the central region is a radially central region.

[0040] In some examples, the radially central region is close to, on, or surrounding the longitudinal axis of the substrate. In some examples, the radially central region is elongate. In some examples, the radially central region forms a core, for example a concentric core, of the substrate. In some examples, the longitudinal axis of the substrate is coincident, or approximately coincident, with the longitudinal axis of the aerosol-generating segment. Radially peripheral refers to a region that is adjacent to, or in contact with, the circumference of the substrate.

[0041] In some examples the central region may comprise a wick. The wick may comprise a substrate and an aerosol former. The wick is typically cylindrical. The wick typically extends the length of the full axial length of the aerosol generating segment. The wick may provide the central region of the substrate, having the first average concentration of aerosol former. The wick may be made from a highly absorbent substrate, such as cotton, cellulose paper or bamboo. The wick may be made from wound fibres, such as wound cellulose fibres (e.g., cotton fibres or bamboo fibres).

[0042] In some examples the central region may comprise a capsule. The capsule may comprise a substrate and an aerosol former. The capsule is typically cylindrical. The capsule may extend the length of the full axial length of the aerosol generating segment. The capsule may provide the central region of the substrate, having the first average concentration of aerosol former. The capsule may include a shell encapsulating the aerosol former. The capsule may include a matrix material (e.g., gel) hosting the aerosol former.

[0043] In some examples, the radially central region spans 50% or more of the length of the substrate. In some examples, the radially central region spans 60% or more, 70% or more, 80% or more, or 90% or more of the length of the substrate. In some examples, the radially central region spans substantially the entire length, or the entire length, of the substrate.

[0044] In some examples, the radially central region spans ≥ 50% and ≤ 95% of the length of the substrate. In some examples, the radially central region spans ≥ 55% and ≤ 90%, ≥ 60% and ≤ 85%, ≥ 65% and ≤ 80%, ≥ 70% and ≤ 80% or about 75% of the length of the substrate.

[0045] In some examples, the radially central region, on average along its length, spans ≥ 1%, ≥ 2%, ≥ 3%, ≥ 4%, ≥ 5%, ≥ 10%, ≥ 20%, or ≥ 30% and ≤ 90%, ≤ 80%, ≤ 70%, ≤ 60%, ≤ 50%, ≤ 40%, ≤ 30%, ≤ 20%, or ≤ 10% of the width of the substrate (e.g. the width is the diameter in the case of a cylindrically-shaped substrate). All of the foregoing values can be used in isolation or combined freely to generate a range bound by a minimum and a maximum (for example, ≥ 50% and ≤ 60%). Here, "radial extent" can be used in place of "width". It is understood that "radial extent" refers to extent in all possible radial directions. As such, reference to a radial direction refers to all possible radial directions.

[0046] In some examples, the radially central region, on average along its length, spans ≥ 1% and ≤ 95% of the width of the substrate. In some examples, the radially central region, on average along its length, spans ≥ 10% and ≤ 90%, ≥ 20% and ≤ 80%, ≥ 30% and ≤ 70%, ≥ 40% and ≤ 60%, or about 50% of the width of the substrate.

[0047] In some examples the radially central region is characterised by being separated (e.g. radially separated) from one or more of the outer edges (e.g. all of the outer edges) or the periphery (e.g. the entire periphery) of the volume taken up by the substrate which run longitudinally. For example, in the case of a cylindrically shaped substrate in a cylindrically shaped aerosol-generating segment, the radially central region is separated from the curved face of the cylinder, but might not be separated from the flat, end faces of the cylinder.

[0048] In some examples, the radially central region can be offset from, or spaced from, the central point of the substrate, or the longitudinal axis, whilst still being a radially central region according to the present invention. In such a case, it is understood that "width" or "radial extent" refers generally to extent in a plane perpendicular to the longitudinal axis. In some examples, the radially central region does not encompass the central point of the substrate, or the longitudinal axis of the substrate. In some examples, ≥ 50%, ≥ 60%, ≥ 70%, ≥ 80%, ≥ 90% or substantially all or all of the radially central region is contained in one half of the substrate (e.g. one lateral half).

[0049] In some examples of the aerosol-generating segment, the central region is a longitudinally central region.

[0050] In some examples, the longitudinally central region is close to, on, or surrounding the length-wise centre of the substrate. In some examples, the longitudinally central region is plug-like, or disc-like. In some examples, the longitudinally central region is separated from the upstream and downstream peripheries of the substrate. A longitudinally peripheral region is adjacent to or connected to the upstream or downstream peripheries of the substrate.

[0051] In some examples, the longitudinally central region is characterised by being separated (i.e. longitudinally separated) from one or more of the edges (e.g. all of the edges) or the peripheries (e.g. all peripheries) at either longitudinal end of the volume taken up by the substrate. For example, in the case of a cylindrically shaped substrate of a cylindrically shaped aerosol forming material, in a cylindrically shaped aerosol-generating segment, the longitudinally central region is separated from the two, flat end faces of the cylinder, but might not be separated from the curved face of the cylinder.

[0052] In some examples, the longitudinally central region spans ≥ 1%, ≥ 2%, ≥ 3%, ≥ 4%, ≥ 5%, ≥ 10%, ≥ 20%, or ≥ 30% and ≤ 90%, ≤ 80%, ≤ 70%, ≤ 60%, ≤ 50%, ≤ 40%, ≤ 30%, ≤ 20%, or ≤ 10% of the length of the substrate. All of the foregoing values can be used in isolation or combined freely to generate a range bound by a minimum and a maximum (for example, ≥ 50% and ≤ 60%).

[0053] In some examples, the longitudinally central region spans ≥ 1% and ≤ 95% of the length of the substrate. In some examples, the longitudinally central region spans ≥ 10% and ≤ 90%, ≥ 20% and ≤ 80%, ≥ 30% and ≤ 70%, ≥ 40% and ≤ 60%, or about 50% of the length of the substrate.

[0054] In some examples, the longitudinally central region, on average along its length, spans 10% or more of the width of the substrate. In some examples, the longitudinally central region, on average along its length, spans 20% or more, 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, 80% or more, or 90% or more of the width of the substrate. In some examples, the longitudinally central region, on average along its length, spans substantially the entire width, or the entire width, of the substrate.

[0055] In some examples, the central region is both radially and longitudinally central, as such the foregoing descriptions of the radially central region and the longitudinally central region can be freely combined where this is physically acceptable. More specifically, in some examples, the radially central region is constrained in its width (radial extent), but not its length, and the longitudinally central region is constrained in its length, but not its width. A central region that is both longitudinally central and radially central is, at least to some extent, constrained in both its length and width relative to the total volume of the substrate.

[0056] Both a radially central and longitudinally central region carry the benefits described above in general terms in relation to a central region. Depending on the context, for example the nature of the consumable in which the aerosol-generating segment is being used, it may be beneficial for the central region to be radially central, longitudinally central, or some combination thereof. Being both radially and longitudinally central prevent aerosol former migration to all outer edges and peripheries of the substrate.

[0057] In some examples, the longitudinally central region can be offset from, or spaced from, the longitudinally central point of the substrate, whilst still being a longitudinally central region according to the present invention. In some examples, the longitudinally central region does not encompass the (longitudinally) central point of the substrate. In some examples, ≥ 50%, ≥ 60%, ≥ 70%, ≥ 80%, ≥ 90% or substantially all or all of the longitudinally central region is contained in one half of the substrate (e.g. one longitudinal half).

[0058] In some examples of the aerosol-generating segment, the central region is formed from a first substrate material and the peripheral region is formed from a second substrate material, wherein the first substrate material has a higher affinity for the aerosol former than the second substrate material.

[0059] In some examples, the affinity for the aerosol former possessed by the first substrate material and the second substrate material means that the central region has a higher affinity for the aerosol former than the peripheral region. Affinity describes the ability of a material to associate with or hold onto the aerosol former. In some examples a higher affinity for aerosol former results from chemical or physical interactions between the material and the aerosol former. For example, associative or favourable chemical bonding interactions between the material and the aerosol former might contribute to the higher affinity of the central region for aerosol former. In some examples, dissociative or unfavourable chemical bonding interactions between the material and the aerosol former might contribute to the lower affinity of the peripheral region for the aerosol former. In some examples, physio-chemical or physical interactions, for example capillary action, might create a higher or lower affinity for aerosol former in a material. For example, associative or favourable physio-chemical or physical interactions between the material and the aerosol former might contribute to the higher affinity of the central region for aerosol former. In some examples, dissociative or unfavourable physio-chemical or physical interactions between the material and the aerosol former might contribute to the lower affinity of the peripheral region for the aerosol former.

[0060] Forming the central region from a first substrate material, and the peripheral region from a second substrate material, prevents aerosol former migration away from the central region. The aerosol former is more likely to remain in the central region where there is a higher affinity for the former, and where it more favourably interacts with the first substrate material.

[0061] In some examples, affinity may manifest in absorbency. In some examples, the first substrate material has a higher absorbency of the aerosol former than the second substrate material.

[0062] In some examples, absorbency may be calculated on a mass basis, wherein the absorbency is calculated as the mass of aerosol former which can be absorbed per unit mass of the substrate material. In some examples, absorbency may be calculated on a volume basis, wherein the absorbency is calculated as the volume of aerosol former which can be absorbed per unit volume of the substrate material. In some examples, absorbency may be calculated on a surface area basis, wherein the absorbency is calculated as the mass of aerosol former which can be absorbed per unit area of the substrate material.

[0063] Absorbency may be measured by any suitable method. In some examples, absorbency may be measured according to ASTM D570-22. In some examples, the absorbency may be measured by drying the substrate material (e.g. in an oven at 70 °C for 6 hours and then in a desiccator at room temperature for 24 hours), recording the dry mass of the substrate material, submerging the substrate material in the aerosol former (e.g. at room temperature for 24 hours), removing the substrate material from the aerosol former, removing excess aerosol former from the surface of the substrate material, and recording the final mass of the absorbed aerosol former and substrate material. The absorbency is then calculated as the difference in final mass and dry mass, as a percentage of the dry mass.

[0064] In some examples, the ratio of the absorbency of the first substrate material to the absorbency of the second substrate material is 51:49 or more, 60:40 or more, 70:30 or more, 80:20 or more, 90:10 or more, or 95:5 or more. In some examples, the ratio of the absorbency of the first substrate material to the absorbency of the second substrate material is from 51:49 to 95:5, from 60:40 to 95:5, from 70:30 to 95:5, from 80:20 to 95:5, from 90:10 to 95:5, from 60:40 to 90:10, from 70:30 to 90:10 or from 80:20 to 90:10.

[0065] In some examples, the absorbency of the first substrate material is 10% or more greater than the absorbency of the second substrate material, such as 20% or more, 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, 80% or more, 90% or more greater. In some examples, the absorbency of the first substrate material is from 10 to 1000% greater than the absorbency of the second substrate material, such as from 20 to 500%, from 30 to 200%, from 40 to 100%, from 50 to 90%, or from 70 to 80% greater.

[0066] In some examples, the first substrate material has an absorbency for the aerosol former of from 20 to 45 wt.%, such as from 25 to 40 wt.%, or from 30 to 35 wt.%, based on the maximum mass of the aerosol former absorbed into the first substrate material.

[0067] In some examples, the second substrate material has an absorbency for the aerosol former of 30 wt.% or less, based on the maximum mass of the aerosol former absorbed into the second substrate material. In some examples, the second substrate material has an absorbency for the aerosol former of from 1 to 25 wt.%, such as from 2 to 20 wt.%, from 3 to 15 wt.%, from 4 to 10 wt.%, or about 5 wt.%, based on the maximum mass of the aerosol former absorbed into the second substrate material.

[0068] In some examples of the aerosol-generating segment, the first substrate material is a hydrophilic material.

[0069] In some examples, the hydrophilic nature of the first substrate material gives it a higher, or high, affinity for aerosol former than the second substrate material. In some examples, as used herein, "hydrophilicity" takes its normal meaning in the art. That is, a hydrophilic material is one which interacts more strongly or strongly or favourably with water and tends to be solvated with water. Here, in some examples, "hydrophilicity" more generally relates to stronger or strong interactions with molecules or moieties capable of forming hydrogen bonds. For example, a hydrophilic material as the first substrate material will have a higher or high affinity for an aerosol former with which it can form strong chemical (e.g. hydrogen) bonds. Here, in some examples, "hydrophilicity" can derive from physio-chemical and physical interactions (e.g. capillary action) which result in a higher or high affinity of a substrate for aerosol former. In some examples, the hydrophilic material is capable of forming hydrogen bonds. In some examples, the first substrate material is a hydroscopic material. In some examples, the hydrophilic nature of the first substrate can be characterised by a static water drop contact angle, θ. In some examples, the hydrophilic material exhibits a static water drop contact angle, θ < 90°. In some examples, θ < 90°, θ < 85°, θ < 80°, θ < 75°, or θ < 70°.

[0070] The aerosol-forming material, such as the substrate of the aerosol-forming material, may comprise plant material.

[0071] The plant material may comprise or be formed of tobacco. Any type of tobacco may be used, including, but is not limited to, flue-cured tobacco, burley tobacco, Virginia tobacco, Maryland Tobacco, dark-air cured tobacco, oriental tobacco, dark-fired tobacco, perique tobacco, rustica tobacco. This also includes blends of the above mentioned tobaccos. Any suitable parts of the tobacco plant may be used, including leaves, stems, roots, bark, seeds and flowers. The tobacco may comprise one or more of leaf tobacco, stem tobacco, tobacco powder, tobacco dust, tobacco derivatives, expanded tobacco, homogenised tobacco, shredded tobacco, extruded tobacco, cut rag tobacco and / or reconstituted tobacco (e.g. slurry recon or paper recon). For example, the aerosol-forming material may comprise a gathered sheet of homogenised (e.g. paper / slurry recon) tobacco or gathered shreds / strips formed from such a sheet.

[0072] The tobacco may be processed tobacco, steam treated stems or shredded dried stems. The tobacco material may be fermented, cured, uncured, toasted, or otherwise pre-treated. The tobacco may be unprocessed and / or untreated.

[0073] The aerosol-forming material may be absent of tobacco and / or nicotine.

[0074] The plant material may comprise at least one plant material selected from the list including Amaranthus dubius, Arctostaphylos uva-ursi (Bearberry), Argemone mexicana, Arnica, Artemisia vulgaris, Yellow Tees, Galea zacatechichi, Canavalia maritima (Baybean), Cecropia mexicana (Guamura), Oestrum noctumum, Cynoglossum virginianum (wild comfrey), Cytisus scoparius, Damiana, Entada rheedii, Eschscholzia califomica (California Poppy), Fittonia albivenis, Hippobroma longi flora, Humulus japonica (Japanese Hops), Humulus lupulus (Hops), Lactuca virosa (Lettuce Opium), Laggera alata, Leonotis leonurus, Leonurus cardiaca (Motherwort), Leonurus sibiricus (Honeyweed), Lobelia cardinalis, Lobelia inflata (Indian-tobacco), Lobelia siphilitica, Nepeta cataria (Catnip), Nicotiana species (Tobacco), Nymphaea alba (White Lily), Nymphaea caerulea (Blue Lily), Opium poppy, Passiflora incamata (Passionflower), Pedicularis densiflora (Indian Warrior), Pedicularis groenlandica (Elephant's Head), Salvia divinorum, Salvia dorrii (Tobacco Sage), Salvia species (Sage), Scutellaria galericulata, Scutellaria lateriflora, Scutellaria nana, Scutellaria species (Skullcap), Sida acuta (Wireweed), Sida rhombi folia, Silene capensis, Syzygium aromaticum (Clove), Tagetes lucida (Mexican Tarragon), Tarchonanthus camphoratus, Tumera diffusa (Damiana), Verbascum (Mullein), Zamia latifolia (Maconha Brava) together with any combinations, functional equivalents to, and / or synthetic alternatives of the foregoing.

[0075] The aerosol-forming material may comprise one or more additives selected from vapour generators, carrier agents, humectants, flavourants, fillers, aqueous / non-aqueous solvents and binders.

[0076] Flavourants may be provided in solid form, liquid form, gel form, or a combination thereof. Flavourants may include one or more of menthol (e.g. peppermint (mentha piperita), spearmint (mentha spicata), wild mint (Mentha Arventis), horse mint (Mentha longifolia), pineapple mint (Mentha suaveolens variegata), applemint (Mentha suaveolens), pennyroyal (Mentha pulegium)), liquorice, chocolate / cocoa, fruit flavour (including e.g. apple, citrus, cherry, banana (Isoamyl acetate)), rose, vanilla (Ethylvanillin), spice (e.g. ginger, clove, cinnamon, star anise), tobacco extract / flavour, marijuana, hemp, cannabinoid compounds, citronella, orange, lemon, geraniol, thyme, fennel, green tea, black tea, coffee, salvia dorrii, salvia, passiflora incarnata, arctostaphylos uva-ursi, lobelia inflata, matcha, Yerba mate, lemon grass, flax, cedar wood, coumarin, helio, eucalyptus, ginkgo biloba, hazel, hibiscus, laurel, chamomile, rosemary, lavender, rooibos, or combinations thereof. The flavourant may be evenly dispersed throughout the aerosol-forming material or may be provided in isolated locations and / or varying concentrations throughout the aerosol-forming material.

[0077] The cannabinoid compounds may be selected from the non-exhaustive list comprising: tetrahydrocannabinol (THC), cannabidiol (CBD), cannabinol (CBN).

[0078] Fillers can strengthen the aerosol-forming material. Fillers may comprise fibrous (non-tobacco) fillers such as cellulose fibres, lignocellulose fibres (e.g. wood fibres), jute fibres and combinations thereof.

[0079] Binders can act to bind together the components forming the aerosol-forming material. Binders may comprise starches and / or cellulosic binders such as methyl cellulose, ethyl cellulose, hydroxy propyl cellulose, hydroxyethyl cellulose and methyl cellulose, gums such as xanthan, guar, arabic and / or locust bean gum, organic acids and their salts such as alginic acid / sodium alginate, agar and pectins.

[0080] The aerosol-forming material may comprises a first substrate material and a second substrate material.

[0081] In some examples of the aerosol-generating segment, the first substrate material comprises a cellulose-based material, optionally wherein the cellulose-based material is at least one selected from the group consisting of: cotton, tobacco, tea, hemp, cellulose, modified cellulose, bamboo fibres, wheat fibres, cellulose monoacetate and paper. Preferably the first substrate material comprises cotton or bamboo.

[0082] In some examples, the first substrate material is a cellulose-based material. In some examples, the first substrate material is a plant-based material. As used herein, "cotton" describes processed or unprocessed cotton or a cotton derived product. As used herein, "cellulose" describes processed or unprocessed cellulose, or a cellulose derived product. As used herein, "tobacco" describes process or unprocessed tobacco, or a tobacco derived product (for example, reconstituted tobacco). As use herein "tea" describes processed or unprocessed tea, or a tea derived product. As used herein "hemp" describes processed or unprocessed hemp, or a hemp derived product. As used herein "paper" describes processed or unprocessed paper, or a paper derived product. The materials used herein may be naturally derived, for example from renewable, sustainable sources.

[0083] In some examples of the aerosol-generating segment, the second substrate material is a hydrophobic material.

[0084] In some examples, the hydrophobic nature of the second substrate material gives it a lower, or low, affinity for aerosol former than the first substrate material. In some examples, as used herein, "hydrophobicity" takes its normal meaning in the art. That is, a hydrophobic material is one which interacts more weakly or weakly or unfavourably with water, and interacts more strongly with non-polar moieties. Here, in some examples, "hydrophobicity" more generally relates to weaker or weak interactions with molecules or moieties capable of forming hydrogen bonds. For example, a hydrophobic material as the second substrate material will have a lower or low affinity for an aerosol former with which it cannot form strong chemical bonds. Here, in some examples, "hydrophobicity" can derive from physio-chemical or physical interactions (e.g. lack of capillary action) which result in a lower or low affinity of a substrate for aerosol former. In some examples, the hydrophobic material is not capable of forming hydrogen bonds. In some examples, the second substrate material is coated with a hydrophobic or oil coating. In some examples, the hydrophobic nature of the second substrate material can be characterised by a static water drop contact angle, θ. In some examples, the hydrophilic material exhibits a static water drop contact angle, θ > 90°. In some examples, θ > 90°, θ > 95°, θ > 100°, θ > 105°, or θ > 110°.

[0085] In some examples of the aerosol-generating segment, the second substrate material comprises at least one selected from the group consisting of: surface modified cellulose, hydrophobically coated fibres, hydrophobically coated cellulose, hydrophobically coated cellulose monoacetate, hydrophobically coated paper, hydrophobically coated cotton, hydrophobically coated tea, hydrophobically coated hemp, polyesters and polyamides.

[0086] In some examples of the aerosol-generating segment, the peripheral region comprises substantially no aerosol former. In some examples, the peripheral region is free of aerosol former. In some examples, the hydrophobic coating is an oil coating.

[0087] As used herein, "cellulose" describes processed or unprocessed cellulose, or a cellulose derived product. As used herein, "fibres" describes a processed or unprocessed fibrous product, or a product derived therefrom. As used herein, "cotton" describes processed or unprocessed cotton or a cotton derived product. As used herein, "polyesters" describes processed or unprocessed polyester materials, or products derived therefrom. As used herein, "polyamides" describes processes or unprocessed polyamide materials, or products derived therefrom. As use herein "tea" describes processed or unprocessed tea, or a tea derived product. As used herein "hemp" describes processed or unprocessed hemp, or a hemp derived product. As used herein "paper" describes processed or unprocessed paper, or a paper derived product. The materials used herein may be naturally derived, for example from renewable, sustainable sources.

[0088] In some examples of the aerosol-generating segment, the change in average concentration of aerosol former between the central region and the peripheral region is continuous.

[0089] The central region of the substrate has a higher average concentration of aerosol former than the peripheral region. In some examples, the average concentration when moving from the central region to the peripheral region changes continuously. That is, the point concentration (or an approximation thereof) across the substrate forms a substantially continuous function, with no significant discontinuities or step changes. In some examples, the change in average concentration between the central region and the peripheral region is smooth. The continuous or smooth change in average concentration can be fast, or it can be slow.

[0090] In some examples where the concentration change between the central region and the peripheral region is continuous, the central region and the peripheral region are formed from the same material. In such a case the central region and the peripheral region might have the same affinity for aerosol former and this might contribute to the continuous change in average aerosol former concentration.

[0091] The rate of change in concentration between the central region and the peripheral region may be 14wt.% / mm or less, calculated in a radial direction based on the wt.% concentration of aerosol former based on the total mass of the aerosol former and substrate. The rate of change in concentration between the central region and the peripheral region may be 5wt.% / mm or more. The rate of change in concentration between the central region and the peripheral region may be from 5 to 14 wt.% / mm, such as 7 to 11 wt.% / mm.

[0092] The change in average concentration can be observed by sampling the substrate at different parts of the segment, and calculating the point concentration. Alternatively, the continuous change in concentration can be observed visually, for example by disassembling the aerosol generating segment.

[0093] In some examples of the aerosol-generating segment, the change in average concentration of aerosol former between the central region and the peripheral region is discrete.

[0094] A discrete change can also be described as a discontinuous change. In some examples, the average concentration when moving from the central region to the peripheral region changes discretely. That is, there is a step change, and the point concentration (or an approximation thereof) across the substrate forms a function with a significant discontinuity or a step change.

[0095] In some examples where the concentration change between the central region and the peripheral region is discrete, the central region and the peripheral region might be formed from first and second substrate materials, respectively, with different affinities for aerosol former which might contribute to the discrete change in average aerosol former concentration.

[0096] The change in average concentration can be observed by sampling the substrate and calculating approximations of the point concentration. Alternatively, the discrete change in concentration can be observed visually.

[0097] The aerosol-former may comprise propylene glycol (PG) and / or vegetable glycerin (VG). Propylene glycol (PG) and vegetable glycerin (VG) are typically used as base materials that act as aerosol generators (alternatively referred to as aerosol-formers), carrier agents, and / or humectants. The aerosol-forming material may comprise, alternatively or in addition, other substances that function as one or more of aerosol generators, carrier agents, and humectants.

[0098] In some examples of the aerosol-generating segment, the aerosol former comprises propylene glycol (PG), vegetable glycerol (VG), or a mixture thereof.

[0099] In some examples, the total amount of aerosol former in the substrate is ≥ 1 mg and ≤ 2500 mg, ≥ 5 mg and ≤ 1250 mg, ≥ 7.5 mg and ≤ 750 mg, ≥ 25 mg and ≤ 750 mg, ≥ 37.5 mg and ≤ 450 mg, ≥ 50 mg and ≤ 250 mg, ≥ 100 mg and ≤ 150mg, or about 125 mg.

[0100] In some examples, the amount of aerosol former per unit length of substrate is ≥ 1 and ≤ 50 mg / mm, ≥ 5 and ≤ 25 mg / mm, ≥ 7.5 and ≤ 15 mg / mm, or about 10 mg / mm.

[0101] In a second aspect, the present disclosure provides a heat-not-burn (HNB) consumable, comprising the aerosol-generating segment of the first aspect.

[0102] In some examples, the heat-not-burn consumable is described as such because the precursor in the aerosol generating segment exhibits heat-not-burn characteristics. In some examples the heat-not-burn consumable comprises further segments. In some examples, the heat-not-burn consumable comprises a cooling segment. In some examples the cooling segment is down stream of the aerosol-generating segment. In such examples the cooling segment is so-called as it cools the aerosol generated when the consumable is in use. In some examples the cooling segment comprises a paper tube. In some examples the cooling segment comprises a spiral paper tube, that is a continuous paper tube, wound in a spiral. In some examples the heat-not-burn consumable comprises further aerosol-generating segments.

[0103] In some examples the heat-not-burn consumable comprises further segments in series with the aerosol-generating segment. In some examples the heat-not-burn consumable comprises one or more filter segments in series, for example downstream, of the aerosol-generating segment. In some examples, all segments of the heat-not-burn consumable are held together by a combination of combining paper and tipping paper which form a wrapping. In some examples the heat-not-burn consumable comprises a mouthpiece filter, at the end of the consumable configured to be engaged by a user when in use.

[0104] In some examples, the heat-not-burn consumable comprises two or more aerosol-generating segments of the first aspect. The two or more aerosol-generating segments of the first aspect may be arranged in series and / or arranged in parallel. In some examples, the heat-not-burn consumable includes two aerosol-generating segments of the first aspect.

[0105] In some examples, the heat-not-burn consumable comprises a first aerosol-generating segment according to the first aspect, and a second aerosol-generating segment according to the first aspect, wherein the first and second aerosol-generating segments are in series with one another or laterally adjacent to one another.

[0106] In some examples, it may be that the heat-not-burn consumable comprises a first aerosol-generating segment according to the first aspect, and a second aerosol-generating segment according to the first aspect in series and optionally adjacent to one another (e.g. they may be in contact or not in contact). In some examples, the first and second aerosol-generating segments are the same, and in some examples they are different. For example, it may be that the central region of the first substrate is a radially central region or a longitudinally central region, and the central region of the second substrate is independently a radially central region or a longitudinally central region.

[0107] In some examples, it may be that the heat-not-burn consumable comprises a first aerosol-generating segment according to the first aspect, and a second aerosol-generating segment according to the first aspect laterally adjacent to one another (e.g. in contact) and running adjacent to each other in a longitudinal direction. In some examples, the first and second aerosol-generating segments are the same, and in some examples they are different. For example, it may be that the central region of the first substrate is a radially central region or a longitudinally central region, and the central region of the second substrate is independently a radially central region or a longitudinally central region.

[0108] In some examples, the heat-not-burn consumable comprises 2, 3, 4, 5 or more aerosol-generating segments according to the first aspect in series or laterally adjacent with one another, or some combination of in series and laterally adjacent and in such a case each aerosol-generating segment may be independently formulated.

[0109] In a fourth aspect, the present disclosure provides an aerosol-generating system comprising the aerosol-generating segment of the first aspect, or a heat-not-burn consumable of the second aspect, and an aerosol-generating unit.

[0110] In some examples the aerosol generating unit comprises a power supply, an aerosol generating unit that is driven by the power supply, a HNB consumable, which in use is aerosolised by the aerosol generating unit to generate an aerosol, and a delivery system for delivery of the aerosol to a user.

[0111] In a fifth aspect, the present disclosure provides a method of manufacturing an aerosol-generating segment according to the first aspect, comprising: providing the substrate and the aerosol former; applying the aerosol former to the substrate to form the aerosol forming material; and wrapping the aerosol forming material with a wrapper to form the aerosol-generating segment.

[0112] In some examples, the method further comprises applying aerosol former to a first portion of the substrate at a first average concentration of aerosol former, applying aerosol former to a second portion of the substrate at a second average concentration of aerosol former, wherein the first average concentration is higher than the second average concentration, and combining the first portion and the second portion to form the central region and peripheral region of the aerosol forming material.

[0113] In some examples, the method further comprises injecting the central region of the substrate with aerosol former to obtain the first average concentration of aerosol former, and optionally injecting the peripheral region of the substrate with aerosol former to obtain the second average concentration of aerosol former, wherein the first average concentration is higher than the second average concentration, to form the aerosol forming material.

[0114] In some examples, the method further comprises differential spraying the aerosol former onto the substrate, to provide the central region with the first average concentration of aerosol former and the peripheral region with the second average concentration of aerosol former, wherein the first average concentration is higher than the second average concentration, to form the aerosol forming material.

[0115] In some examples, the method comprises: (i) preparing the central region of the substrate, the central region comprising the first average concentration of aerosol former, and preparing the peripheral region of the substrate, the peripheral region comprising the second average concentration of aerosol former, wherein the first average concentration is higher than the second average concentration, and then combining the central and peripheral regions to form the aerosol forming material of the aerosol-generating segment; or (ii) providing the substrate and injecting the central region with aerosol former to obtain the first average concentration of aerosol former and injecting the peripheral region with aerosol former to obtain the second average concentration of aerosol former, wherein the first average concentration is higher than the second average concentration, to form the aerosol forming material of the aerosol-generating segment; or (iii) providing the substrate and using differential spraying to provide the central region with the first average concentration of aerosol former and the peripheral region with the second average concentration of aerosol former, wherein the first average concentration is higher than the second average concentration, to form the aerosol forming material of the aerosol-generating segment.

[0116] In some examples, the method comprises (i). In some examples, when the method comprises (i), the central region and the peripheral region comprise or are formed from the same material. In some examples, when the method comprises (i), the central region and the peripheral region comprise or are formed from first and second substrate materials, respectively, with different affinities for aerosol former, as described above. In some examples, the central region and the peripheral region are held together by an adhesive.

[0117] In some examples, the central region and the peripheral region are injected with aerosol former to achieve desired first and second average concentrations of aerosol former, respectively. In some examples, the central region and the peripheral region are sprayed with a desired amount of aerosol former (i.e. using differential spraying). In some examples, the peripheral region comprises no aerosol former. In some examples, the central and peripheral regions are combined by wrapping the peripheral region around the central region.

[0118] In some examples, the method comprises (ii). In some examples, when the method comprises (ii) the central region and the peripheral region are formed from the same material. In some examples, when the method comprises (ii), the central region and the peripheral region are formed from first and second substrate materials, respectively, with different affinities for aerosol former, as described above.

[0119] In some examples, the method comprises (iii). In some examples, when the method comprises (iii), the central region and the peripheral region comprise or are formed from the same material. In some examples, when the method comprises (iii), the central region and the peripheral region comprise or are formed from first and second substrate materials, respectively, with different affinities for aerosol former, as described above.

[0120] In a sixth aspect, the present disclosure provides a use of the aerosol-generating segment of the first aspect or the heat-not-burn consumable of the second aspect to prevent or reduce aerosol former migration.

[0121] In some examples, there is provided the use of a first average concentration of an aerosol former in a central region of a substrate of an aerosol forming material of an aerosol-generating segment, and a second average concentration of the aerosol former in a peripheral region of the substrate of the aerosol forming material of the aerosol-generating segment, wherein the first average concentration is higher than the second average concentration, to prevent, reduce or minimise aerosol former migration.

[0122] In some examples, the use of a higher average concentration of an aerosol former in a central region of a substrate of an aerosol-generating segment compared to a peripheral region of a substrate of the aerosol-generating segment achieves reduced aerosol former migration within the substrate, segment, or a consumable comprising the aerosol-generating segment.

[0123] In some examples, the present disclosure provides for the use of an aerosol-generating segment of the first aspect. In some examples this achieves reduced aerosol former migration within the substrate, segment, or a consumable comprising the aerosol-generating segment.

[0124] The present disclosure may provide a method of generating an aerosol which may implement any one or more features disclosed herein. The method may comprise heating the aerosol generating segment of the first aspect to generate an aerosol.

[0125] The preceding summary is provided for purposes of summarizing some examples to provide a basic understanding of aspects of the subject matter described herein. Accordingly, the above-described features should not be construed to narrow the scope or spirit of the subject matter described herein in any way. Moreover, the above and / or proceeding examples may be combined in any suitable combination to provide further examples, except where such a combination is clearly impermissible or expressly avoided. Other features, aspects, and advantages of the subject matter described herein will become apparent from the following text and the accompanying drawings.BRIEF DESCRIPTION OF THE FIGURES

[0126] Aspects, features and advantages of the present disclosure will become apparent from the following description of examples in reference to the appended drawings in which like numerals denote like elements. Fig. 1 is a block system diagram showing an example aerosol generating apparatus. Fig. 2 is a block system diagram showing an example implementation of the apparatus of Fig. 1, where the aerosol generating apparatus is configured to generate aerosol from a solid precursor. Fig. 3 is a schematic diagram showing an example implementation of the apparatus of Fig. 2. Fig. 4 is a schematic diagram showing an example implementation of an aerosol-generating segment according to the present disclosure, illustrating a generic central region of a substrate of such a segment. Fig. 5 is a schematic diagram showing an example implementation of an aerosol generating-segment according to the present disclosure, illustrating a radially central region of a substrate of such a segment. Fig. 6 is a schematic diagram showing an example implementation of an aerosol-generating segment according to the present disclosure, illustrating a longitudinally central region of a substrate of such a segment. Fig. 7 is a schematic diagram showing an example implementation of an aerosol-generating segment according to the present disclosure, illustrating a radially central region of a substrate of such a segment, where the radially central region is formed from or comprises a first aerosol-generating material, and the peripheral region is formed from or comprises a second aerosol-generating material, and wherein the first aerosol-generating material has a greater affinity for aerosol former than the second aerosol-generating material. Fig. 8 is a schematic diagram showing an example implementation of an aerosol-generating segment according to the present disclosure, illustrating a radially central region of a substrate of such a segment, wherein the radially central region is offset from the longitudinal axis of the substrate. Fig. 9 is a schematic diagram showing an example implementation of an aerosol-generating segment according to the present disclosure, illustrating a longitudinally central region of a substrate of such a segment, wherein the longitudinally central region is offset from the longitudinally central point of the substrate. Fig. 10 is a schematic diagram showing a portion of an example implementation of a heat-not-burn consumable according to the present disclosure, comprising two laterally adjacent aerosol-generating segments, each segment comprising a substrate with a radially central region. Fig. 11 is a schematic diagram showing a portion of an example implementation of a heat-not-burn consumable according to the present disclosure, comprising two aerosol-generating segments in series with one another, each segment comprising a substrate with a longitudinally central region. Fig. 12 is a cross-sectional, schematic drawing of an example implementation of a heat-not-burn consumable according to the present disclosure, comprising an aerosol-generating segment according to the present disclosure, and further downstream segments. DETAILED DESCRIPTION OF EMBODIMENTS

[0127] Before describing several examples implementing the present disclosure, it is to be understood that the present disclosure is not limited by specific construction details or process steps set forth in the following description and accompanying drawings. Rather, it will be apparent to those skilled in the art having the benefit of the present disclosure that the systems, apparatuses and / or methods described herein could be embodied differently and / or be practiced or carried out in various alternative ways.

[0128] Unless otherwise defined herein, scientific and technical terms used in connection with the presently disclosed inventive concept(s) shall have the meanings that are commonly understood by those of ordinary skill in the art, and known techniques and procedures may be performed according to conventional methods well known in the art and as described in various general and more specific references that may be cited and discussed in the present specification.

[0129] Any patents, published patent applications, and non-patent publications mentioned in the specification are hereby incorporated by reference in their entirety.

[0130] All examples implementing the present disclosure can be made and executed without undue experimentation in light of the present disclosure. While particular examples have been described, it will be apparent to those of skill in the art that variations may be applied to the systems, apparatus, and / or methods and in the steps or in the sequence of steps of the methods described herein without departing from the concept, spirit, and scope of the inventive concept(s). All such similar substitutions and modifications apparent to those skilled in the art are deemed to be within the spirit, scope, and concept of the inventive concept(s) as defined by the appended claims.

[0131] The use of the term "a" or "an" in the claims and / or the specification may mean "one," as well as "one or more," "at least one," and "one or more than one." As such, the terms "a," "an," and "the," as well as all singular terms, include plural referents unless the context clearly indicates otherwise. Likewise, plural terms shall include the singular unless otherwise required by context.

[0132] The use of the term "or" in the present disclosure (including the claims) is used to mean an inclusive "and / or" unless explicitly indicated to refer to alternatives only or unless the alternatives are mutually exclusive. For example, a condition "A or B" is satisfied by any of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).

[0133] As used in this specification and claim(s), the words "comprising, "having," "including," or "containing" (and any forms thereof, such as "comprise" and "comprises," "have" and "has," "includes" and "include," or "contains" and "contain," respectively) are inclusive or open-ended and do not exclude additional, unrecited elements or method steps.

[0134] Unless otherwise explicitly stated as incompatible, or the physics or otherwise of the embodiments, examples, or claims prevent such a combination, the features of examples disclosed herein, and of the claims, may be integrated together in any suitable arrangement, especially ones where there is a beneficial effect in doing so. This is not limited to only any specified benefit, and instead may arise from an "ex post facto" benefit. This is to say that the combination of features is not limited by the described forms, particularly the form (e.g. numbering) of example(s), embodiment(s), or dependency of claim(s).

[0135] Moreover, this also applies to the phrase "in one embodiment," "according to an embodiment," and the like, which are merely a stylistic form of wording and are not to be construed as limiting the following features to a separate embodiment to all other instances of the same or similar wording. This is to say, a reference to 'an,' 'one,' or 'some' embodiment(s) may be a reference to any one or more, and / or all embodiments, or combination(s) thereof, disclosed. Also, similarly, the reference to "the" embodiment may not be limited to the immediately preceding embodiment. Further, all references to one or more embodiments or examples are to be construed as non-limiting to the claims.

[0136] The present disclosure may be better understood in view of the following explanations, wherein the terms used that are separated by "or" may be used interchangeably: As used herein, an "aerosol generating apparatus " (or "electronic(e)-cigarette ") may be an apparatus configured to deliver an aerosol to a user for inhalation by the user. The apparatus may additionally / alternatively be referred to as a "smoking substitute apparatus", if it is intended to be used instead of a conventional combustible smoking article. As used herein a combustible "smoking article" may refer to a cigarette, cigar, pipe or other article, that produces smoke (an aerosol comprising solid particulates and gas) via heating above the thermal decomposition temperature (typically by combustion and / or pyrolysis).

[0137] As used herein, a "consumable " may refer to a component that includes an aerosol forming material (i.e. a substrate and aerosol former). The component may include an aerosol generating unit. The component may include a mouthpiece. The component may be referred to as a "stick" or "package" or "heat-not-burn consumable". In a heat-not-burn consumable, the mouthpiece may be implemented as a filter and the consumable may be arranged to carry the precursor. The consumable may be implemented as a dosage or pre-portioned amount of material, including a loose-leaf product. The aerosol generating component e.g. the stick, package or consumable may be for releasable coupling to a device body to form the aerosol generating apparatus. The device body may comprise a power supply for powering the aerosol generating unit.

[0138] An aerosol generated by the apparatus may comprise an aerosol with particle sizes of 0.2 - 7 microns, or less than 10 microns, or less than 7 microns. This particle size may be achieved by control of one or more of: heater temperature; cooling rate as the vapour condenses to an aerosol; flow properties including turbulence and velocity. The generation of aerosol by the aerosol generating apparatus may be controlled by an input device. The input device may be configured to be user-activated, and may for example include or take the form of an actuator (e.g. actuation button) and / or an airflow sensor.

[0139] Each occurrence of the aerosol generating apparatus being caused to generate aerosol for a period of time (which may be variable) may be referred to as an "activation" of the aerosol generating apparatus. The aerosol generating apparatus may be arranged to allow an amount of aerosol delivered to a user to be varied per activation (as opposed to delivering a fixed dose of aerosol), e.g. by activating an aerosol generating unit of the apparatus for a variable amount of time, e.g. based on the strength / duration of a draw of a user through a flow path of the apparatus (to replicate an effect of smoking a conventional combustible smoking article).

[0140] The aerosol generating apparatus may be portable. As used herein, the term "portable " may refer to the apparatus being for use when held by a user.

[0141] As used herein, an "aerosol generating system " may be a system that includes an aerosol generating apparatus and optionally other circuitry / components associated with the function of the apparatus, e.g. one or more external devices and / or one or more external components (here "external" is intended to mean external to the aerosol generating apparatus). As used herein, an "external device" and "external component" may include one or more of a: a charging device, a mobile device (which may be connected to the aerosol generating apparatus, e.g. via a wireless or wired connection); a networked-based computer (e.g. a remote server); a cloud-based computer; any other server system.

[0142] An example aerosol generating system may be a system for managing an aerosol generating apparatus. Such a system may include, for example, a mobile device, a network server, as well as the aerosol generating apparatus.

[0143] As used herein, an "aerosol " may include a suspension of precursor, including as one or more of: solid particles; liquid droplets; gas. Said suspension may be in a gas including air. An aerosol herein may generally refer to / include a vapour. An aerosol may include one or more components of the precursor.

[0144] As used herein, a "precursor" may include one or more of a: liquid; solid; gel; loose leaf material; other substance. The precursor specifically includes at least a substrate and aerosol former. The precursor may be processed by an aerosol generating unit of an aerosol generating apparatus to generate an aerosol. The precursor may include one or more of: an active component; a carrier; a flavouring. The active component may include one or more of nicotine; caffeine; a cannabidiol oil; a non-pharmaceutical formulation, e.g. a formulation which is not for treatment of a disease or physiological malfunction of the human body. The active component may be carried by the carrier, which may be a liquid, including propylene glycol and / or glycerine. The term "flavouring" may refer to a component that provides a taste and / or a smell to the user. The flavouring may include one or more of: Ethylvanillin (vanilla); menthol, Isoamyl acetate (banana oil); or other. The substrate may be, e.g. reconstituted tobacco to carry one or more of the active component; a carrier; a flavouring.

[0145] As used herein, a "storage portion " may be a portion of the apparatus adapted to store the precursor.

[0146] As used herein, a "flow path " may refer to a path or enclosed passageway through an aerosol generating apparatus, e.g. for delivery of an aerosol to a user. The flow path may be arranged to receive aerosol from an aerosol generating unit. When referring to the flow path, upstream and downstream may be defined in respect of a direction of flow in the flow path, e.g. with an outlet being downstream of an inlet.

[0147] As used herein, a "delivery system " may be a system operative to deliver an aerosol to a user. The delivery system may include a mouthpiece and a flow path. The delivery system may be at least partly within the aerosol generating component.

[0148] As used herein, a "flow " may refer to a flow in a flow path. A flow may include aerosol generated from the precursor. The flow may include air, which may be induced into the flow path via a puff by a user.

[0149] As used herein, a "puff" (or "inhale " or "draw ") by a user may refer to expansion of lungs and / or oral cavity of a user to create a pressure reduction that induces flow through the flow path.

[0150] As used herein, an "aerosol generating unit " may refer to a device configured to generate an aerosol from a precursor or aerosol-generating segment. The aerosol generating unit may include a unit to generate a vapour directly from the precursor (e.g. a heating system or other system). A plurality of aerosol generating units to generate a plurality of aerosols (for example, from a plurality of different aerosol forming materials) may be present in an aerosol generating apparatus.

[0151] As used herein, a "heating system " may refer to an arrangement of at least one heating element, which is operable to aerosolise a precursor once heated. The at least one heating element may be electrically resistive to produce heat from the flow of electrical current therethrough. The at least one heating element may be arranged as a susceptor to produce heat when penetrated by an alternating magnetic field. The heating system may be configured to heat a precursor to below 300 or 350 degrees C, including without combustion. The heating system may be provided within the aerosol generating component or within the device body.

[0152] As used herein, an "information carrying medium " may include one or more arrangements for storage of information on any suitable medium. Examples include: a computer readable medium; a Radio Frequency Identification (RFID) transponder; codes encoding information, such as optical (e.g. a bar code or QR code) or mechanically read codes (e.g. a configuration of the absence or presents of cutouts to encode a bit, through which pins or a reader may be inserted).

[0153] As used herein "heat-not-burn " (or "HNB " or "heated precursor ") may refer to the heating of a precursor, typically tobacco, without combustion, or without substantial combustion (i.e. localised combustion may be experienced of limited portions of the precursor, including of less than 5% of the total volume).

[0154] As used herein a "non-uniform" distribution describes a distribution which comprises some combination of global maxima and minima. A non-unform distribution of aerosol-former features some combination of global maxima and minima in aerosol former concentration.

[0155] As used herein "substrate" refers to material which is capable of generating an aerosol when heated in combination with an aerosol former. Examples include cotton, tobacco, tea, hemp, cellulose and paper. In the present invention, the substrate comprises a non-uniform distribution of aerosol former, with a higher average concentration in a central region than in a peripheral region. The substrate and aerosol former combination can be referred to as a precursor. The substrate and former (i.e. precursor) is wrapped in a wrapper (e.g. combining paper) to form an "aerosol-generating segment ", usable in a consumable.

[0156] As used herein "aerosol former" refers to a liquid substance capable of being aerosolised. Examples include propylene glycol and vegetable glycerin.

[0157] Referring to Fig. 1, an example aerosol generating apparatus 1 includes a power supply 2, for supply of electrical energy. The apparatus 1 includes an aerosol generating unit 4 that is driven by the power supply 2. The power supply 2 may include an electric power supply in the form of a battery and / or an electrical connection to an external power source. The apparatus 1 includes a precursor 6, which in use is aerosolised by the aerosol generating unit 4 to generate an aerosol. The apparatus 1 includes a delivery system 8 for delivery of the aerosol to a user. In the present invention, the precursor in an aerosol-generating segment includes a substrate that has a higher average concentration of aerosol former in a central region than in a peripheral region. Electrical circuitry (not shown in figure 1) may be implemented to control the interoperability of the power supply 2 and aerosol generating unit 4.

[0158] Fig. 2 shows an implementation of the apparatus 1 of Fig. 1, where the aerosol generating apparatus 1 is configured to generate aerosol by a heat-not-burn process. In this example, the apparatus 1 includes a device body 50 and a consumable 70. In this example, the body 50 includes the power supply 2 and a heating system 52. The heating system 52 includes at least one heating element 54. The body may additionally include any one or more of electrical circuitry 56, a memory 58, a wireless interface 60, one or more other components 62. The electrical circuitry 56 may include a processing resource for controlling one or more operations of the body 50, e.g. based on instructions stored in the memory 58. The wireless interface 60 may be configured to communicate wirelessly with an external (e.g. mobile) device, e.g. via Bluetooth.

[0159] The other component(s) 62 may include an actuator, one or more user interface devices configured to convey information to a user and / or a charging port, for example (see e.g. Fig. 3).

[0160] The body 50 may be configured to engage with the consumable 70 such that the at least one heating element 54 of the heating system 52 penetrates into the solid precursor 6 of the consumable. In use, a user may activate the aerosol generating apparatus 1 to cause the heating system 52 of the body 50 to cause the at least one heating element 54 to heat the solid precursor 6 of the consumable (without combusting it) by conductive heat transfer, to generate an aerosol which is inhaled by the user.

[0161] Fig. 3 shows an example implementation of the aerosol generating device 1 of Fig. 2. As depicted in Fig. 3, the consumable 70 is implemented as a stick, which is engaged with the body 50 by inserting the stick into an aperture at a top end 53 of the body 50, which causes the at least one heating element 54 of the heating system 52 to penetrate into the solid precursor 6.

[0162] The consumable 70 includes the solid precursor 6, part of an aerosol-generating segment, proximal to the body 50, and a filter distal to the body 50. The filter serves as the mouthpiece of the consumable 70 and thus the apparatus 1 as a whole. The solid precursor 6 may be a reconstituted tobacco formulation. The precursor includes a substrate which features a higher concentration of aerosol former in a central region than in a peripheral region.

[0163] In this example, the at least one heating element 54 is a rod-shaped element with a circular transverse profile. Other heating element shapes are possible, e.g. the at least one heating element may be blade-shaped (with a rectangular transverse profile) or tube-shaped (e.g. with a hollow transverse profile).

[0164] In this example, the body 50 includes a cap 51. In use the cap 51 is engaged at a top end 53 of the body 50. Although not apparent from Fig. 3, the cap 51 is moveable relative to the body 50. In particular, the cap 51 is slidable and can slide along a longitudinal axis of the body 50.

[0165] The body 50 also includes an actuator 55 on an outer surface of the body 50. In this example, the actuator 55 has the form of a button.

[0166] The body 50 also includes a user interface device configured to convey information to a user. Here, the user interface device is implemented as a plurality of lights 57, which may e.g. be configured to illuminate when the apparatus 1 is activated and / or to indicate a charging state of the power supply 2. Other user interface devices are possible, e.g. to convey information haptically or audibly to a user.

[0167] The body may also include an airflow sensor which detects airflow in the aerosol generating apparatus 1 (e.g. caused by a user inhaling through the consumable 70). This may be used to count puffs, for example.

[0168] In this example, the consumable 70 includes a flow path which transmits aerosol generated by the at least one heating element 54 to the mouthpiece of the consumable.

[0169] In this example, the aerosol generating unit 4 is provided by the above-described heating system 52 and the delivery system 8 is provided by the above-described flow path and mouthpiece of the consumable 70.

[0170] Fig. 4 illustrates an aerosol-generating segment 100 according to one implementation of the present disclosure. The aerosol-generating segment 100 comprises a substrate 120, and a wrapper 140. The substrate comprises a central region 122 and a peripheral region 124. The substrate comprises an aerosol former, the aerosol former being non-uniformly distributed throughout the substrate, and being at higher average concentration in the central region 122 compared to the peripheral region 124. The substrate 120 and the aerosol former comprise the aerosol forming material. Fig. 4 includes a longitudinal axis 130 and a radial direction 132 which extends from the longitudinal axis.

[0171] Fig. 5 illustrates an aerosol-generating segment 100 according to one implementation of the present disclosure. The aerosol-generating segment 100 comprises a substrate 120, and a wrapper 140. The substrate comprises a central region 122 and a peripheral region 124. The substrate comprises an aerosol former, the aerosol former being non-uniformly distributed throughout the substrate and being at higher average concentration in the central region 122 compared to the peripheral region 124. The aerosol former and the substrate 120 comprise the aerosol forming material. In Fig. 5, the central region is a radially central region. That is, the radial extent of the central region 122 is constrained in a radial direction 132, and the central region does not extend to the curved face of the cylindrical substrate 120.

[0172] The longitudinal extent, in a longitudinal direction, illustrated by longitudinal axis 130, of the radially central region is not constrained, and in Fig. 5 the central region 122 spans the entire length of the substrate 120.

[0173] Fig. 6 illustrates an aerosol-generating segment 100 according to one implementation of the present disclosure. The aerosol-generating segment 100 comprises a substrate 120, and a wrapper 140. The substrate comprises a central region 122 and a peripheral region 124. The substrate 120 comprises an aerosol former, the aerosol former being non-uniformly distributed throughout the substrate, and being at higher average concentration in the central region 122 compared to the peripheral region 124.

[0174] The aerosol former and the substrate 120 comprise the aerosol forming material. In Fig. 6, the central region is a longitudinally central region. That is, the longitudinal extent (i.e. length) of the central region 122 is constrained in a longitudinal direction illustrated by longitudinal axis 130, and the central region does not extend to either of the flat end faces of the cylindrical substrate 120. The radial extent in a radial direction 132 of the longitudinally central region is not constrained, and in Fig. 6, the central region 122 spans the entire width (i.e. diameter) of the substrate 120.

[0175] Fig. 7 illustrates an aerosol-generating segment 100 according to one implementation of the present disclosure. The aerosol-generating segment 100 comprises a substrate 120, and a wrapper 140. The substrate comprises a central region 122 and a peripheral region 124. The substrate comprises an aerosol former, the aerosol former being non-uniformly distributed throughout the substrate, and being at higher average concentration in the central region 122 compared to the peripheral region 124. The aerosol former and the substrate 120 comprise the aerosol forming material. Like in Fig. 5, in Fig. 7 the central region is a radially central region. That is, the radial extent of the central region 122 is constrained in a radial direction 132, and the central region does not extend to the curved face of the cylindrical substrate 120. The longitudinal extent, in a longitudinal direction illustrated by longitudinal axis 130, of the radially central region is not constrained, and in Fig. 7 the central region 122 spans the entire length of the substrate 120. Additionally, In Fig. 7, the central region is formed from a first substrate material and the peripheral region is formed from a second substrate material, wherein the first substrate material has a higher affinity for the aerosol former than the second substrate material. In Fig. 7, the first substrate material is a hydrophilic material, for example cotton, tobacco, tea, hemp, modified cellulose and paper. The aerosol-generating segment 100 in Fig. 7 can be formed, for example, by preparing the central region 122 and preparing the peripheral region 124 seperately, each with a desired amount of former, and then combining them. For example, the central region 122 is formed from a plug of first substrate material, and this is wrapped by a second substrate material and enclosed in a wrapper 140.

[0176] Fig. 8 illustrates an aerosol-generating segment 100 according to one implementation of the present disclosure. The aerosol-generating segment 100 comprises a substrate 120, and a wrapper 140. The substrate comprises a central region 122 and a peripheral region 124. The substrate comprises an aerosol former, the aerosol former being non-uniformly distributed throughout the substrate, and being at higher average concentration in the central region 122 compared to the peripheral region 124. The substrate 120 and aerosol former comprise the aerosol forming material. That is, the radial extent of the central region 122 is constrained in a radial direction 132, and the central region does not extend to the curved face of the cylindrical substrate 120. In Fig. 8, the radially central region is offset from the longitudinal axis of the substrate, and therefore offset from the central point of the substrate. As such, the "radial extent" as used here is understood to more generally include extent in a plane perpendicular to the longitudinal axis. The longitudinal extent, in a longitudinal direction, illustrated by longitudinal axis 130, of the radially central region is not constrained, and in Fig. 8 the central region 122 spans the entire length of the substrate 120.

[0177] Fig. 9 illustrates an aerosol-generating segment 100 according to one implementation of the present disclosure. The aerosol-generating segment 100 comprises a substrate 120, and a wrapper 140. The substrate comprises a central region 122 and a peripheral region 124. The substrate comprises an aerosol former, the aerosol former being non-uniformly distributed throughout the substrate, and being at higher average concentration in the central region 122 compared to the peripheral region 124. The substrate 120 and aerosol former comprise the aerosol forming material. In Fig. 9, the central region is a longitudinally central region. That is, the longitudinal extent (i.e. length) of the central region 122 is constrained in a longitudinal direction illustrated by longitudinal axis 130, and the central region does not extend to either of the flat end faces of the cylindrical substrate 120. In Fig. 9, the longitudinally central region is offset from the longitudinal centre of the substrate. The radial extent in a radial direction 132 of the longitudinally central region is not constrained, and in Fig. 9, the central region 122 spans the entire width (i.e. diameter or radial extent) of the substrate 120.

[0178] Fig. 10 illustrates a portion of a heat-not-burn consumable 300 comprising a first aerosol-generating segment 100, and a second aerosol-generating segment 100'. The aerosol-generating segments 100 and 100' comprise a substrates 120 and 120', respectively. Both aerosol-generating segments are bound by a wrapper 140. The substrates 120 and 120' comprise central regions 122 and 122', respectively and peripheral regions 124 and 124', respectively. The substrates 120 and 120' each comprise an aerosol former, the aerosol former being non-uniformly distributed throughout the substrates, and being at higher average concentration in the central regions 122 and 122', compared to the peripheral regions 124 and 124', respectively. The substrates 120, 120' and aerosol former comprise the aerosol forming materials. In Fig. 10, the central regions 122 and 122' are radially central regions. That is, the radial extent of the central regions 122 and 122' is constrained in a radial direction 132, and the central regions do not extend to the outer sides of the substrates 120 and 120', respectively. In Fig. 10, aerosol-generating segments 100 and 100' are laterally adjacent and both the first and second substrates 120 and 120' are prismatic with semi-circular end faces, and are in contact via each of their rectangular faces along a plane marked 134 with a hashed fill. The longitudinal extent, in a longitudinal direction, illustrated by longitudinal axis 130, of the radially central regions is not constrained, and in Fig. 10 the central regions 122 and 122' span the entire length of the substrates 120 and 122', respectively.

[0179] Fig. 11 illustrates a portion of a heat-not-burn consumable 300 comprising a first aerosol-generating segment 100, and a second aerosol-generating segment 100'. The aerosol-generating segments 100 and 100' comprise substrates 120 and 120', respectively. Both aerosol-generating segments are bound by a wrapper 140. The substrates 120 and 120' comprise central regions 122 and 122', respectively, and peripheral regions 124 and 124', respectively. The substrates 120 and 120' each comprise an aerosol former, the aerosol former being non-uniformly distributed throughout the substrates, and being at higher average concentration in the central regions 122 and 122' compared to the peripheral regions 124 and 124', respectively. The substrates 120, 120' and aerosol former comprise the aerosol forming materials. In Fig. 11, the central regions 122 and 122' are longitudinally central regions. That is, the longitudinal extent (i.e. length) of the central regions 122 and 122' is constrained in a longitudinal direction illustrated by longitudinal axis 130, and the central regions do not extend to either of the flat end faces of the cylindrical substrates 120 and 120'. In Fig. 11, the first and second aerosol-generating segments 100 and 100' are in series and meet at a plane created by the end faces of the aerosol-generating segments 100 and 100' that lies between central regions 122 and 122', marked as 134 with a hashed fill. The radial extent in a radial direction 132 of the longitudinally central regions is not constrained, and in Fig. 11, the central regions 122 and 122' span the entire width (i.e. diameter) of the substrates 120 and 120', respectively.

[0180] Generally, the aerosol-generating segments 100 in Fig. 4 to Fig. 11 can be manufactured in a number of ways. These include (i) preparing the central region 122 of the substrate 120, the central region comprising the first average concentration of aerosol former, and preparing the peripheral region 124 of the substrate 120, the peripheral region 124 comprising the second average concentration of aerosol former, wherein the first average concentration is higher than the second average concentration, and then combining the central 122 and peripheral 124 regions to form the aerosol forming material of the aerosol-generating segment 100; or (ii) providing the substrate 120 and injecting the central region 122 with aerosol former to obtain the first average concentration of aerosol former and injecting the peripheral region 124 with aerosol former to obtain the second average concentration of aerosol former, wherein the first average concentration is higher than the second average concentration, to form the aerosol forming material of the aerosol-generating segment 100; or (iii) providing the substrate 120 and using differential spraying to provide the central region 122 with the first average concentration of aerosol former and the peripheral region 124 with the second average concentration of aerosol former, wherein the first average concentration is higher than the second average concentration, to form the aerosol forming material of the aerosol-generating segment 100; and wrapping the aerosol forming material with a wrapper 140 to form the aerosol-generating segment 100.

[0181] Fig. 12 is a cross-sectional diagram of an example implementation of a heat-not-burn consumable 70, including the aerosol-generating segment 100 of the invention. The aerosol-generating segment 100 includes substrate 120, central region 122 and peripheral region 124 and is according to the example in Fig. 5. The aerosol-generating segment 100, is located at the upstream end of the consumable 70. Downstream of the aerosol-generating segment 100 is a tubular segment 410. The tubular segment 410 may be known as a cooling segment. Downstream of the tubular segment 410 is a mouthpiece filter 420. The mouthpiece filter 420 is at the downstream end of the consumable 70. The aerosol-generating segment 100, the tubular segment 410 and the mouthpiece filter 420 are wrapped together using wrapper 140. The wrapper 140 is wrapped around the segments and glued into place using an adhesive.

Claims

1. An aerosol-generating segment for a heat-not-burn consumable, the aerosol-generating segment comprising: an aerosol forming material, comprising a substrate and an aerosol former; and a wrapper circumscribing the aerosol forming material; wherein the aerosol former is non-uniformly distributed in the substrate, such that there is a first average concentration of aerosol former in a central region of the substrate and a second average concentration of aerosol former in a peripheral region of the substrate, wherein the first average concentration is higher than the second average concentration.

2. The aerosol-generating segment of claim 1, wherein the central region is a radially central region.

3. The aerosol-generating segment of claim 1 or claim 2, wherein the central region is a longitudinally central region.

4. The aerosol-generating segment of any one of claims 1 to 3, wherein the central region is formed from a first substrate material and the peripheral region is formed from a second substrate material, wherein the first substrate material has a higher affinity for the aerosol former than the second substrate material.

5. The aerosol-generating segment of claim 4, wherein the first substrate material is a hydrophilic material.

6. The aerosol-generating segment of claim 4 or claim 5, wherein the first substrate material comprises a cellulose-based material, optionally wherein the cellulose-based material is at least one selected from the group consisting of: cotton, tobacco, tea, hemp, cellulose, modified cellulose, bamboo fibres, wheat fibres, cellulose monoacetate and paper.

7. The aerosol-generating segment of any one of claims 4 to 6, wherein the second substrate material is a hydrophobic material.

8. The aerosol-generating segment of any one of claims 4 to 7, wherein the second substrate material comprises at least one selected from the group consisting of: surface modified cellulose, hydrophobically coated fibres, hydrophobically coated cellulose, hydrophobically coated cellulose monoacetate, hydrophobically coated paper, hydrophobically coated cotton, hydrophobically coated tea, hydrophobically coated hemp, polyesters and polyamides.

9. The aerosol-generating segment of any one of claims 1 to 8, wherein the aerosol former comprises propylene glycol (PG), vegetable glycerol (VG), or a mixture thereof.

10. The aerosol-generating segment of any one of claims 1 to 9, wherein the change in average concentration of aerosol former between the central region and the peripheral region is discrete.

11. A heat-not-burn consumable comprising the aerosol-generating segment of any one of claims 1 to 10.

12. A heat-not-burn consumable of claim 11, wherein the heat-not-burn consumable comprises two or more aerosol-generating segments of any one of claims 1 to 10, wherein the two or more aerosol-generating segments are arranged in series and / or are arranged in parallel.

13. An aerosol generating system comprising the heat-not-burn consumable of claim 11 or 12, and an aerosol-generating unit.

14. A method of manufacturing an aerosol-generating segment according to any one of claims 1 to 10, comprising: providing the substrate and the aerosol former; applying the aerosol former to the substrate to form the aerosol forming material; and wrapping the aerosol forming material with a wrapper to form the aerosol-generating segment.

15. The method of claim 14, wherein the method further comprises: (i) applying aerosol former to a first portion of the substrate at a first average concentration of aerosol former, applying aerosol former to a second portion of the substrate at a second average concentration of aerosol former, wherein the first average concentration is higher than the second average concentration, and combining the first portion and the second portion to form the central region and peripheral region of the aerosol forming material; or (ii) injecting the central region of the substrate with aerosol former to obtain the first average concentration of aerosol former, and optionally injecting the peripheral region of the substrate with aerosol former to obtain the second average concentration of aerosol former, wherein the first average concentration is higher than the second average concentration, to form the aerosol forming material; or (iii) differential spraying the aerosol former onto the substrate, to provide the central region with the first average concentration of aerosol former and the peripheral region with the second average concentration of aerosol former, wherein the first average concentration is higher than the second average concentration, to form the aerosol forming material.

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