An Aerosol Generating Article

The present disclosure relates generally to an aerosol generating article, and more particularly to an aerosol generating article for an aerosol generating device.

The popularity and use of reduced-risk or modified-risk devices (also known as vaporisers) has grown rapidly in recent years as an alternative to the use of traditional tobacco products. Various devices and systems are available that heat or warm, rather than burn, an aerosol generating substrate to generate an aerosol for inhalation by a user.

A commonly available reduced-risk or modified-risk device is an aerosol generating device, or so-called heat-not-burn device. Devices of this type generate an aerosol or vapour by heating an aerosol generating substrate, for instance comprised in an aerosol generating article such as a heated tobacco stick, to a temperature typically in the range 150° C. to 300° C., in a heating compartment. Heating the aerosol generating substrate to a temperature within this range, without burning or combusting the aerosol generating substrate, generates a vapour which typically cools and condenses to form an aerosol for inhalation by a user of the device.

Typically, used aerosol generating articles for disposal are stored by a user with new unused aerosol generating articles until an opportunity for disposal arises. A user must therefore distinguish between new and used aerosol generating articles. In prior art arrangements, this can be difficult in view of the similarity in appearance of new and used aerosol generating articles. If a user, by error, attempts to vape a used aerosol generating article they will have a negative sensorial experience, and possibly have increased health risks. Furthermore, battery power will be wasted, such that the device may require recharging before the next vaping session. There is, therefore, a need to provide aerosol generating articles which mitigate this drawback.

According to a first aspect of the present disclosure, there is provided an aerosol generating article for an aerosol generating device, wherein the aerosol generating article comprises an aerosol generating substrate and a filter circumscribed by a wrapper, wherein at least a portion of the filter comprises a thermochromic material and a flavouring, wherein the thermochromic material is capable of undergoing a temperature dependent irreversible colour change at or above a threshold temperature to cause a colour change of the at least a portion of the filter. The filter preferably comprises a tip, and the thermochromic material is preferably comprised in the tip of the filter, and most preferably comprised only in the tip of the filter.

A user can readily distinguish between new and used aerosol generating articles based on the colour change of the at least a portion of the filter. A user is therefore considerably less likely to erroneously select a used aerosol generating article for vaping, for instance when new and used aerosol generating articlesare stored together, and thus experience the associated negative sensorial experience, health risks and wasted battery usage. The used aerosol generating articles also have an aesthetically pleasing appearance based on the colour change. When the thermochromic material is comprised in the tip of the filter, the colour change or absence thereof may be easily visible to the user when the aerosol generating articles are stored on end in a packet, assisting the user in distinguishing between new and used aerosol generating articles without the need to first extract the articles from the packet. Providing the thermochromic material only in the tip of the filter may reduce material usage, and may also provide an aesthetically pleasing surprise for the user following use of the aerosol generating article.

Below the threshold temperature the colour of the at least a portion of the filter may be determined by the thermochromic material. Below the threshold temperature the colour of the at least a portion of the filter may be indicative of the identity of the flavouring. This provides a clear visual indication of the flavouring present.

The thermochromic material and/or flavouring may be impregnated into the material of the at least a portion of the filter, e.g. into the material of the tip of the filter. The thermochromic material and/or flavouring may be evenly dispersed throughout the at least a portion of the filter. Alternatively, the concentration of thermochromic material and/or flavouring comprised in the at least a portion of the filter may vary at different locations. The thermochromic material and/or flavouring may be comprised in the at least a portion of the filter only at selected isolated locations.

The thermochromic material and/or flavouring may be comprised in a portion only of the filter, e.g. only in the tip of the filter. This can reduce materials used and thus costs. Alternatively, the thermochromic material and/or flavouring may be comprised in the whole of the filter. This can be visually more striking.

Possibly, the threshold temperature is from 50° C. to 250° C., or from 100° C. to 250° C.

The thermochromic material may comprise any of: copper (I) iodide (CuI), 2Cu(CNS)·2pyridine, or ammonium metavanadate (NHVO).

Possibly, the thermochromic material and the flavouring are comprised in a solution and wherein the at least a portion of the filter comprises the solution.

According to a second aspect of the present disclosure, there is provided a method of manufacturing an aerosol generating article for an aerosol generating device, wherein the aerosol generating article comprises an aerosol generating substrate and a filter circumscribed by a wrapper, wherein the method comprises:

Preferably the filter comprises a tip, and the thermochromic material is incorporated only in the tip of the filter.

Possibly, the thermochromic material and flavouring is comprised in a solution, wherein the method comprises:

Possibly, the thermochromic material and flavouring is comprised in a solution, wherein the method comprises:

Possibly, the solution comprises a carrier solvent, wherein the method comprises:

Embodiments of the present disclosure will now be described by way of example only and with reference to the accompanying drawings.

Referring to, there is shown diagrammatically an aerosol generating articleaccording to the present disclosure. The aerosol generating articleis configured to be used with an aerosol generating device, for instance as shown diagrammatically in. The aerosol generating articleand the aerosol generating devicetogether form an aerosol generating system.

The aerosol generating devicemay equally be referred to as a “heated tobacco device”, a “heat-not-burn tobacco device”, a “device for vaporising tobacco products”, and the like, with this being interpreted as a device suitable for achieving these effects. The features disclosed herein are equally applicable to devices which are designed to vaporise any aerosol generating substrate.

The aerosol generating deviceis a hand-held, portable, device, by which it is meant that a user is able to hold and support the device unaided, in a single hand. The aerosol generating devicehas a first (or proximal) endand a second (or distal) endand comprises a device housing.

The aerosol generating deviceincludes a controller. The aerosol generating devicemay include a user interface for controlling the operation of the aerosol generating devicevia the controller.

The controlleris configured to detect the initiation of use of the aerosol generating device, for example, in response to a user input, such as a button press to activate the aerosol generating device, or in response to a detected airflow through the aerosol generating device. As will be understood by one of ordinary skill in the art, an airflow through the aerosol generating deviceis indicative of a user inhalation or ‘puff’. The aerosol generating devicemay, for example, include a puff detector, such as an airflow sensor (not shown), to detect an airflow through the aerosol generating device.

The controllerincludes electronic circuitry. The aerosol generating deviceincludes a power source, such as a battery. The power sourceand the electronic circuitry may be configured to operate at a high frequency in the case of an inductively heated vapour generating device. For example, the power sourceand the electronic circuitry may be configured to operate at a frequency of between approximately 80 kHz and 500 kHz, possibly between approximately 150 kHz and 250 kHz, and possibly at approximately 200 kHz. The power sourceand the electronic circuitry could be configured to operate at a higher frequency, for example in the MHz range, if required.

The aerosol generating devicecomprises a heating assembly. The heating assemblyfurther comprises a heating compartment. The heating compartmentis arranged to receive an aerosol generating articleaccording to examples of the present disclosure. In some examples, the heating compartmenthas a substantially cylindrical cross-section. The heating compartmentdefines a cavity.

The heating compartmenthas a first endand a second end. The heating compartmentincludes an openingat the first endfor receiving an aerosol generating article. In the illustrated example, the heating compartmentincludes a substantially cylindrical side wall, i.e., a side wallwhich has a substantially circular cross-section.

The aerosol generating articleaccording to examples of the disclosure comprises an aerosol generating substrate. The aerosol generating substratemay be any type of solid or semi-solid material. Example types of aerosol generating solids include powder, granules, pellets, shreds, strands, particles, gel, strips, loose leaves, cut leaves, cut filler, porous material, foam material or sheets. The aerosol generating substratemay comprise plant derived material and in particular, may comprise tobacco. It may advantageously comprise reconstituted tobacco. The aerosol generating substratemay be a tobacco plug.

The aerosol generating substratemay comprise an aerosol-former. Examples of aerosol-formers include polyhydric alcohols and mixtures thereof such as glycerine or propylene glycol. Typically, the aerosol generating substratemay comprise an aerosol-former content of between approximately 5% and approximately 50% on a dry weight basis. In some example, the aerosol generating substratemay comprise an aerosol-former content of between approximately 10% and approximately 20% on a dry weight basis, and possibly approximately 15% on a dry weight basis.

Upon heating, the aerosol generating substratemay release volatile compounds. The volatile compounds may include nicotine or flavour compounds such as tobacco flavouring.

Typically, the shape of the aerosol generating articlecorresponds to the shape of the heating compartment. The aerosol generating articlemay be generally cylindrical or rod-shaped. The aerosol generating articlemay be formed substantially in the shape of a stick, and may broadly resemble a cigarette, having a tubular region with the aerosol generating substratearranged in a suitable manner. The aerosol generating articlemay be a disposable and replaceable article which may, for example, contain tobacco as the aerosol generating substrate. The aerosol generating articlemay be a heated tobacco stick. The aerosol generating articleis a consumable.

The aerosol generating articlehas a first end(or mouth end), a second end, and comprises a filterat the first end. The filteracts as a mouthpiece and may comprise an air-permeable plug, for example comprising cellulose acetate fibres.

In illustrated example, the aerosol generating articlecomprises a first section, a second section, and a third section. The first sectioncomprises the aerosol generating substrate, i.e., a tobacco plug. In the illustrated example, the full extent of the first sectionis not shown. The second sectionincludes a vapour outlet channel. The vapour outlet channelcomprises a hollow tube, for instance, an acetate tube. The third sectionincludes the filter.

In the illustrated example, the filtercomprises a mouthpiece filterand a polymer-film filter. The aerosol generating substrateand filterare circumscribed by a wrapper, which in examples of the disclosure is a paper wrapper, and are thus embodied as an aerosol generating article. In the illustrated example, a secondary paper wrapper, i.e., a mouth-end paper, is provided at the first end. The wrappermay be permeable. The wrapperis an outer wrapper. One or more vapour collection regions, cooling regions, and other structure may also be included in some designs.

To use the aerosol generating device, a user inserts an aerosol generating articlethrough the openinginto the heating compartment, so that the second endof the aerosol generating articleis positioned at the second endof the heating compartmentand so that the filterat the first endof the aerosol generating articleprojects from the first endof the heating compartmentto permit engagement by a user's lips.

The heating assemblycomprises a heater, i.e., a heating element, arranged to heat the aerosol generating substrateof an aerosol generating articlereceived in the heating compartment.

The heating assemblymay be an induction heating assembly (not shown). The induction heating assembly further comprises an induction coil (not shown). The induction coil is arranged to be energised to generate an alternating electromagnetic field for inductively heating an induction heatable susceptor (not shown). Accordingly, in such examples the heateris an induction heatable susceptor.

The induction heatable susceptor may be arranged around the periphery of the heating compartment. Alternatively, the induction heatable susceptor may be arranged to project into the heating compartmentfrom the second end(e.g., as a heating blade or pin) to penetrate the aerosol generating substratewhen the aerosol generating articleis inserted into the aerosol generating device. In other examples, the induction heatable susceptor is instead provided in the aerosol generating substrateduring manufacture of the aerosol generating article. In such examples, the aerosol generating articlecomprises the induction heatable susceptor.

The induction coil can be energised by the power sourceand controller. The induction coil may comprise a Litz wire or a Litz cable. It will, however, be understood that other materials could be used.

The induction coil may extend around the heating compartment. Accordingly, the induction coil may be annular. The induction coil may be substantially helical in shape. In some examples, the circular cross-section of a helical induction coil may facilitate the insertion of an aerosol generating articleand optionally one or more induction heatable susceptors, into the heating compartmentand ensure uniform heating of the aerosol generating substrate.

The induction heatable susceptor comprises an electrically conductive material. The induction heatable susceptor may comprise one or more, but not limited to, of graphite, molybdenum, silicon carbide, niobium, aluminium, iron, nickel, nickel containing compounds, titanium, mild steel, stainless steel, low carbon steel and alloys thereof, e.g., nickel chromium or nickel copper, and composites of metallic materials. In some examples, the induction heatable susceptor comprises a metal selected from the group consisting of mild steel, stainless steel, and low carbon stainless steel.

In use, with the application of an electromagnetic field in its vicinity, the induction heatable susceptor(s) generate heat due to eddy currents and magnetic hysteresis losses resulting in a conversion of energy from electromagnetic to heat.

The induction coil may be arranged to operate in use with a fluctuating electromagnetic field having a magnetic flux density of between approximately 20 mT and approximately 2.0 T at the point of highest concentration.

An alternative approach is to employ a resistive heating assembly (not shown). In such cases, the heateris a resistive heater (not shown). The resistive heater may surround the aerosol generating substrateand transfer heat to an outer surface of the aerosol generating substrate, for instance, the resistive heater may be arranged around the periphery of the heating compartment. Alternatively, the resistive heater may be arranged to project into the heating compartmentfrom the second end(e.g., as a heating blade or pin) to penetrate the aerosol generating substratewhen the aerosol generating articleis inserted into the aerosol generating device. In use, current from the power supplyis supplied directly to the resistive heater to generate heat.

In examples of the disclosure, at least a portion of the filterof the aerosol generating articlecomprises a thermochromic material and a flavouring. The thermochromic material is capable of undergoing a temperature dependent irreversible colour change at or above a threshold temperature to cause a colour change of the at least a portion of the filter. The colour change of the at least a portion of the filteris therefore permanent. The colour change is a visual change, i.e., results in a change in the appearance of the at least a portion of the filter.

A user can readily distinguish between new and used aerosol generating articlesbased on the colour change of the at least a portion of the filter. A user is therefore considerably less likely to erroneously select a used aerosol generating articlefor vaping, for instance when new and used aerosol generating articlesare stored together, and thus experience the associated negative sensorial experience, health risks and wasted battery usage. The used aerosol generating articles also have an aesthetically pleasing appearance based on the colour change.

In some examples, the threshold temperature is from 50° C. to 250° C. The threshold temperature may be from 50° C. to 200° C. The threshold temperature may be from 50° C. to 300° C. The threshold temperature may be from 150° C. to 300° C. The threshold temperature may be from 150° C. to 250° C., or from 100° C. to 250° C. The threshold temperature may be from 60° C. to 220° C. The threshold temperature may be less than 300° C., and may be less than 250° C., and may be less than 200° C. The threshold temperature may be at least 50° C., and may be at least 100° C. The threshold temperature is greater than a maximum storage temperature of aerosol generating articlesand may be lower than a minimum vaping temperature. In examples of the disclosure, the thermochromic material undergoes a temperature dependent irreversible colour change when vapour at or above the threshold temperature passes through the filterand encounters, i.e., traverses, the thermochromic material. Accordingly, it is the vapour temperature which determines whether or not the threshold temperature is met.

The thermochromic material may comprise, for example, copper (I) iodide (CuI), 2Cu(CNS)·2pyridine, or ammonium metavanadate (NHVO). At or above a transition temperature of 60° C. to 62° C., copper (I) iodide causes a colour change from grey tan to orange. At or above a transition temperature of 135° C., 2Cu(CNS)·2pyridine causes a colour change from green to yellow. At or above a transition temperature of 220° C., 2Cu(CNS)·2pyridine causes a colour change from yellow to black. At or above a transition temperature of 150° C., ammonium metavanadate causes a colour change from white to brown. At or above a transition temperature of 170° C., ammonium metavanadate causes a colour change from brown to black.

In some examples, the thermochromic material may comprise a number of different discrete chemical compounds, for instance, more than one of copper (I) iodide (CuI), 2Cu(CNS)·2pyridine, or ammonium metavanadate (NHVO).

The thermochromic material may be a dye, or may be comprised in a dye formulation. The thermochromic material may be an ink, or comprised in an ink formulation.

A flavouring also known as a flavour, flavouring agent or flavourant is any substance that gives another substance taste. The flavouring may be a volatile flavour-generating component. The flavouring may be provided in solid or liquid form. The flavouring may include, but is not limited to, any of the following: menthol or menthol-like substances, liquorice, chocolate, fruit flavour or essence (e.g., citrus, cherry, etc.), vanilla, spice (e.g., ginger, cinnamon), and tobacco flavour. In some examples the flavouring also provides a fragrance.