Method for Manufacturing Aerosol Generating Articles

The present application is a continuation of U.S. patent application Ser. No. 18/026,536, filed on Mar. 15, 2023, which application is a national phase entry under 35 U.S.C. § 371 of International Application No. PCT/EP2021/075595, filed Sep. 17, 2021, published in English, which claims priority to European Application No. 20 197 157.9 filed, Sep. 21, 2020, the disclosures of which are incorporated herein by reference.

The present disclosure relates generally to aerosol generating articles, and more particularly to an aerosol generating article for use with an aerosol generating device for heating the aerosol generating article to generate an aerosol for inhalation by a user. Embodiments of the present disclosure relate in particular to a method for continuously manufacturing aerosol generating articles. The present disclosure is particularly applicable to the manufacture of aerosol generating articles for use with a portable (hand-held) aerosol generating device.

The popularity and use of reduced-risk or modified-risk devices (also known as aerosol generating devices or vapour generating devices) 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 aerosol generating substances to generate an aerosol for inhalation by a user.

A commonly available reduced-risk or modified-risk device is the heated substrate 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 to a temperature typically in the range 150° C. to 300° C. 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.

Currently available aerosol generating devices can use one of a number of different approaches to provide heat to the aerosol generating substrate. One such approach is to provide an aerosol generating device which employs an induction heating system. In such a device, an induction coil is provided in the device and an inductively heatable susceptor is provided to heat the aerosol generating substrate. Electrical energy is supplied to the induction coil when a user activates the device which in turn generates an alternating electromagnetic field. The susceptor couples with the electromagnetic field and generates heat which is transferred, for example by conduction, to the aerosol generating substrate and an aerosol is generated as the aerosol generating substrate is heated.

It can be convenient to provide both the aerosol generating substrate and the inductively heatable susceptor together, in the form of an aerosol generating article which can be inserted by a user into an aerosol generating device. As such, there is a need to provide a method which facilitates the manufacture of aerosol generating articles, and in particular which enables aerosol generating articles to be mass-produced easily and consistently.

According to a first aspect of the present disclosure, there is provided a method for continuously manufacturing aerosol generating articles, the method comprising:

Aerosol generating articles produced by the method are for use with an aerosol generating device for heating the aerosol generating substrate, without burning the aerosol generating substrate, to volatise at least one component of the aerosol generating substrate and thereby generate a heated vapour which cools and condenses to form an aerosol for inhalation by a user of the aerosol generating device. The aerosol generating device is a hand-held, portable, device.

In general terms, a vapour is a substance in the gas phase at a temperature lower than its critical temperature, which means that the vapour can be condensed to a liquid by increasing its pressure without reducing the temperature, whereas an aerosol is a suspension of fine solid particles or liquid droplets, in air or another gas. It should, however, be noted that the terms ‘aerosol’ and ‘vapour’ may be used interchangeably in this specification, particularly with regard to the form of the inhalable medium that is generated for inhalation by a user.

The method according to the present disclosure facilitates the manufacture of aerosol generating articles and in particular enables aerosol generating articles to be mass produced consistently and with relative ease. Because the aerosol generating strips are formed during step (iii) without cutting the at least one susceptor patch, wear during the cutting step (e.g., on a cutting unit) is minimised. The combination of aerosol generating strips and a susceptor (formed without cutting the susceptor patch into strips) in aerosol generating articles produced by the method according to the present disclosure provides effective heat transfer from the susceptor to the aerosol generating strips during use of the aerosol generating articles in an aerosol generating device. This in turn provides effective and uniform heating of the aerosol generating strips and, thus, reliable vapour generation.

Accurate and consistent positioning of the at least one susceptor patch along the centre line of the substantially flat surface of the continuous web of aerosol generating substrate further helps to ensure that aerosol generating articles manufactured by the method according to the present disclosure have consistent and repeatable characteristics.

Step (iii) may be performed using a rotary cutter unit. The rotary cutter unit may include a first cutting drum and a second cutting drum. The first cutting drum may have circumferentially extending first cutting formations. The second cutting drum may have circumferentially extending second cutting formations. The first and second cutting formations may cooperate to cut the exposed regions of the continuous web of aerosol generating substrate to form the plurality of aerosol generating strips. The use of a rotary cutter unit allows continuous, and high-speed, manufacture of aerosol generating articles to be readily achieved.

The first cutting drum and the second cutting drum may define therebetween a non-cutting region. The non-cutting region may accommodate the at least one susceptor patch and a part of the aerosol generating substrate to which the at least one susceptor patch is applied during step (ii). The provision of a non-cutting region ensures that the susceptor patch and underlying part of the aerosol generating substrate (which acts as an elongate carrier strip for the susceptor patch) are not cut whilst assuring that high-speed manufacture is obtained.

The first cutting drum may be formed without the first cutting formations in the non-cutting region. For example, the first cutting drum may include a circumferentially extending recess in its surface in the non-cutting region. The second cutting drum may be formed without the second cutting formations in the non-cutting region. For example, the second cutting drum may include a circumferentially extending recess in its surface in the non-cutting region. In some embodiments, both of the first and second cutting drums may be formed respectively without the first and second cutting formations in the non-cutting region. In some embodiments, at least part of the at least one susceptor patch may be accommodated in the circumferentially extending recess. These arrangements reliably ensure that the susceptor patch and underlying part of the aerosol generating substrate (i.e., the elongate carrier strip) are not cut during step (iii) and that high-speed manufacture is obtained.

Each of the plurality of aerosol generating strips may have a width of between approximately 0.1 mm and 5.0 mm, possibly between approximately 0.5 mm and 2.0 mm. Each of the plurality of aerosol generating strips may have a width of 1.0 mm. These width dimensions ensure that aerosol generating articles manufactured using the method according to the present disclosure contain a suitable number of aerosol generating strips to allow uniform airflow through the aerosol generating article and the generation of an acceptable quantity of vapour or aerosol. If the width of the aerosol generating strips is too low, the strength of the strips may be reduced and, consequently, mass production of aerosol generating articles may become difficult.

Step (ii) may comprise adhering the at least one susceptor patch to the substantially flat surface of the continuous web of aerosol generating substrate using an adhesive. A good bond between the susceptor patch and the continuous web of aerosol generating substrate is thereby achieved, ensuring that the susceptor patch does not move relative to the continuous web of aerosol generating substrate. This in turn may help to ensure that only the exposed regions of the continuous web of aerosol generating substrate are cut during step (iii) to form the aerosol generating strips.

Step (ii) may comprise consecutively applying a plurality of susceptor patches to the substantially flat surface of the continuous web of aerosol generating substrate with a predefined and constant spacing between each successive susceptor patch. The predefined and constant ‘spacing’ between each successive susceptor patch is the shortest distance between successive (i.e., adjacent) susceptor patches, i.e., the distance or gap between the edges of successive (i.e., adjacent) susceptor patches. Step (iii) may comprise cutting the exposed regions of the continuous web of aerosol generating substrate to form a plurality of aerosol generating strips on each side of the susceptor patches. Step (iv) may comprise forming the plurality of aerosol generating strips and the susceptor patches into a continuous rod. The mass production of aerosol generating articles is thereby readily achieved.

The at least one susceptor patch may have a length between 5 mm and 50 mm, preferably between 10 mm and 30 mm. The at least one susceptor patch may have a width between 0.1 mm and 7 mm, preferably between 1 mm and 5 mm. The at least one susceptor patch may have a thickness between 1 um and 500 μm, preferably between 10 μm and 100 μm, possibly approximately 50 μm. Susceptor patches with these dimensions are particularly suitable for the manufacture of aerosol generating articles.

The method may further comprise (v) cutting the continuous rod to form a plurality of individual aerosol generating articles. Each individual aerosol generating article may comprise at least one susceptor patch. Thus, step (v) may comprise cutting the continuous rod to form a plurality of individual aerosol generating articles each comprising at least one susceptor patch. Continuous and mass production of aerosol generating articles is, thereby, readily achieved.

Step (v) may comprise cutting the continuous rod at a position between adjacent susceptor patches. Cutting the continuous rod in this way ensures that the individual aerosol generating articles formed by cutting the continuous rod each comprise a susceptor patch and, thus, that the aerosol generating articles are consistent and repeatable. Also, because the susceptor patches are not cut during step (v), wear during the cutting step (e.g., on a cutting unit) is minimised.

Step (v) may comprise cutting the continuous rod substantially at a midpoint between adjacent susceptor patches. In this way, the susceptor is spaced inwardly from both ends of the resultant aerosol generating article and is not visible at either end of the aerosol generating article. This may improve the user acceptance of aerosol generating articles manufactured by the method according to the present disclosure. Furthermore, the susceptor is fully embedded in the aerosol generating substrate (i.e., aerosol generating strips) of the resultant aerosol generating article, and this may allow an aerosol or vapour to be generated more effectively because the whole of the susceptor is surrounded by the aerosol generating strips and, therefore, heat transfer from the susceptor to the aerosol generating strips is maximised.

Each susceptor patch may comprise an inductively heatable susceptor material, such as one or more, but not limited, of aluminium, iron, nickel, stainless steel, carbon steel, and alloys thereof, e.g. Nickel Chromium or Nickel Copper. With the application of an electromagnetic field in its vicinity during use of the aerosol generating article in an aerosol generating device, the susceptor material may generate heat due to eddy currents and magnetic hysteresis losses resulting in a conversion of energy from electromagnetic to heat.

The aerosol generating substrate may 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 substrate may comprise plant derived material and in particular, may comprise tobacco. It may advantageously comprise reconstituted tobacco, for example including tobacco and any one or more of cellulose fibres, tobacco stalk fibres and inorganic fillers such as CaCO3.

Consequently, the aerosol generating device with which the aerosol generating articles are intended for use may 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 continuous rod may be circumscribed by a paper wrapper. Thus, the method may further comprise wrapping the continuous rod with a paper wrapper.

The aerosol generating article may be formed substantially in the shape of a stick, and may broadly resemble a cigarette, having a tubular region with an aerosol generating substrate arranged in a suitable manner. The aerosol generating article may include a filter segment, for example comprising cellulose acetate fibres, at a proximal end of the aerosol generating article. The filter segment may constitute a mouthpiece filter and may be in coaxial alignment with an aerosol generating substrate constituted by the plurality of aerosol generating strips. One or more vapour collection regions, cooling regions, and other structures may also be included in some designs. For example, the aerosol generating article may include at least one tubular segment upstream of the filter segment. The tubular segment may act as a vapour cooling region. The vapour cooling region may advantageously allow the heated vapour generated by heating the aerosol generating strips to cool and condense to form an aerosol with suitable characteristics for inhalation by a user, for example through the filter segment.

The aerosol generating substrate may comprise an aerosol-former. Examples of aerosol-formers include polyhydric alcohols and mixtures thereof such as glycerine or propylene glycol. Typically, the aerosol generating substrate may comprise an aerosol-former content of between approximately 5% and approximately 50% on a dry weight basis. In some embodiments, the aerosol generating substrate may 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 substrate (i.e., aerosol generating strips) may release volatile compounds. The volatile compounds may include nicotine or flavour compounds such as tobacco flavouring.

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

Referring initially to, there is shown an example of an aerosol generating articlefor use with an aerosol generating device that comprises an induction heating system to inductively heat the aerosol generating article and thereby generate an aerosol for inhalation by a user of the device. Such devices are known in the art and will not be described in further detail in this specification. The aerosol generating articleis elongate and substantially cylindrical. The circular cross-section facilitates handling of the articleby a user and insertion of the articleinto a cavity or heating compartment of an aerosol generating device.

The aerosol generating articlecomprises an aerosol generating substratehaving first and second endsand an inductively heatable susceptor. The aerosol generating substrateand the inductively heatable susceptorare positioned in, and enclosed by, a wrapper. The wrappercomprises a material which is substantially non-electrically conductive and non-magnetically permeable. In the illustrated example, the wrapperis a paper wrapper and may comprise cigarette paper.

The aerosol generating articlemay have a total length, measured between the distal endand the proximal (mouth) endbetween 30 mm and 100 mm, preferably between 50 mm and 70 mm, possibly approximately 55 mm. The aerosol generating substratemay have a total length, measured between the first and second endsbetween 5 mm and 50 mm, preferably between 10 mm and 30 mm, possibly approximately 20 mm. The aerosol generating articlemay have a diameter between 5 mm and 10 mm, preferably between 6 mm and 8 mm, possibly approximately 7 mm.

The aerosol generating substratecomprises a plurality of elongate first stripscomprising an aerosol generating material. The plurality of elongate first stripsconstitute aerosol generating stripsand are substantially oriented in a longitudinal direction of the aerosol generating article. The elongate first stripsare typically foldless in the longitudinal direction to ensure that the air flow route is not interrupted and that a uniform air flow through the articlecan be achieved.

The inductively heatable susceptorcomprises an elongate second stripcomprising an inductively heatable susceptor material. The elongate second stripcan, therefore, be regarded as a strip-shaped or blade-shaped elongate susceptorwhich is also substantially oriented in the longitudinal direction of the aerosol generating article. As can be clearly seen in, each of the elongate first stripshas a width which is less than a width of the elongate second strip.

The aerosol generating articlecomprises at least one elongate carrier striphaving first and second major surfacesThe elongate carrier stripcomprises an aerosol generating material and, thus, also constitutes an aerosol generating strip. The elongate carrier stripis substantially oriented in the longitudinal direction of the aerosol generating article. The elongate carrier striphas the same length as the elongate first strips, and thus the aerosol generating stripswithin the aerosol generating articleall have the same length.

The elongate second stripis adhered to the elongate carrier stripand, as can be clearly seen in, the elongate carrier striphas a width which is greater than the width of the elongate second strip. The elongate second striphas first and second opposite facesThe second faceis adhered to the second major surfaceof the elongate carrier stripand is covered in its entirety by the elongate carrier strip, and more particularly by the second major surface

The elongate first strips, the elongate second stripand the elongate carrier stripare arranged to form a substantially rod-shaped aerosol generating articleand the elongate first stripscan be randomly distributed throughout the cross-section of the rod-shaped aerosol generating articlesuch that they have a plurality of different orientations within the cross-section of the aerosol generating article. Although not apparent from, a sufficient number of elongate first stripsare provided to substantially fill the cross-section of the aerosol generating substrate, and it will be understood that a smaller number of elongate first stripsare shown merely for illustration purposes. The elongate second stripand the elongate carrier stripare positioned roughly centrally within the cross-section of the aerosol generating substrate, and hence the aerosol generating article. Such an arrangement helps to ensure that there is uniform heat transfer from the elongate second stripto the elongate first strips.

As best seen in, the centrally positioned elongate carrier stripand the elongate second stripadhered thereto define first and second regions,within the cross-section of the aerosol generating substrateand, hence, within the cross-section of the aerosol generating article. The first regionfaces the first major surfaceof the elongate carrier stripand the second regionfaces the second major surfaceof the elongate carrier strip. The first and second regions,both include a plurality of elongate first strips.

As best seen in, each of the plurality of elongate first stripshas a distal endand the elongate second striphas a distal endThe distal endsof the elongate first stripsform the first endof the aerosol generating substrateand, correspondingly, the distal endof the aerosol generating article. The elongate second stripis shorter than the elongate first stripsand the elongate carrier strip. The distal endof the elongate second stripis positioned inwardly from the distal endsof the elongate first strips. The distal endof the elongate second strip(i.e., the elongate susceptor) is, therefore, not visible at the distal endof the aerosol generating article.

The aerosol generating articlecomprises a mouthpiece segmentpositioned downstream of the aerosol generating substrate. The aerosol generating substrateand the mouthpiece segmentare arranged in coaxial alignment inside the wrapperto hold the components in position to form the rod-shaped aerosol generating article.

In the illustrated embodiment, the mouthpiece segmentcomprises the following components arranged sequentially and in co-axial alignment in a downstream direction, in other words from the distal endto the proximal (mouth) endof the aerosol generating article: a cooling segment, a center hole segmentand a filter segment. The cooling segmentcomprises a hollow paper tubehaving a thickness which is greater than the thickness of the paper wrapper. The center hole segmentmay comprise a cured mixture containing cellulose acetate fibres and a plasticizer, and functions to increase the strength of the mouthpiece segment. The filter segmenttypically comprises cellulose acetate fibres and acts as a mouthpiece filter. As heated vapour flows from the aerosol generating substratetowards the proximal (mouth) endof the aerosol generating article, the vapour cools and condenses as it passes through the cooling segmentand the center hole segmentto form an aerosol with suitable characteristics for inhalation by a user through the filter segment.

The elongate first stripsand the elongate carrier striptypically comprise plant derived material, such as tobacco. The elongate first stripsand the elongate carrier stripcan advantageously comprise reconstituted tobacco including tobacco and any one or more of cellulose fibres, tobacco stalk fibres and inorganic fillers such as CaCO3.

The elongate first stripsand the elongate carrier striptypically comprise an aerosol-former such as glycerine or propylene glycol. Typically, the elongate first stripsand the elongate carrier stripcomprise an aerosol-former content of between approximately% and approximately 50% on a dry weight basis. Upon heating, the elongate first stripsand the elongate carrier striprelease volatile compounds possibly including nicotine or flavour compounds such as tobacco flavouring.

When a time varying electromagnetic field is applied in the vicinity of the elongate second stripduring use of the articlein an aerosol generating device, heat is generated in the elongate second stripdue to eddy currents and magnetic hysteresis losses. The heat is transferred from the elongate second stripto the elongate first stripsand the elongate carrier stripto heat the elongate first stripsand the elongate carrier stripwithout burning them to release one or more volatile compounds and thereby generate a vapour. As a user inhales through the filter segment, the heated vapour is drawn in a downstream direction through the articlefrom the first endof the aerosol generating substratetowards the second endof the aerosol generating substrate, and towards the filter segment. As noted above, as the heated vapour flows through the cooling segmentand the center hole segmenttowards the filter segment, the heated vapour cools and condenses to form an aerosol with suitable characteristics for inhalation by a user through the filter segment.

Manufacture of Aerosol Generating Articles

Apparatusand methods suitable for manufacturing aerosol generating articles according to the present disclosure, such as the aerosol generating articledescribed above with reference to, will now be described.

Referring to, there is shown a diagrammatic illustration of an apparatusand method for manufacturing the aerosol generating articledescribed above with reference tois a plan view of an aerosol generating substrateand susceptor patchesas they move through the apparatus, in the direction of the arrow in

The apparatuscomprises a substrate supply reel(e.g. a first bobbin) which carries a continuous webof an aerosol generating substratehaving a substantially flat surface with a centre lineand first feed rollersfor controlling the feed of the continuous webof aerosol generating substrate. The apparatusmay also include a web tension regulator and a web edge control system as will be understood by one of ordinary skill in the art, but these additional components are not essential in the context of the present disclosure and have, therefore, been omitted for the sake of simplicity.

The apparatuscomprises a susceptor supply reel(e.g. a second bobbin) which carries a continuous webof susceptor material, feed rollers,for controlling the feed of the continuous webof susceptor material, an adhesive applicator unit, and a susceptor cutting unit.

The apparatusfurther comprises an optional heater, a strip cutting unit, feed rollers, a rod forming unit, and a rod cutting unit.