CN111629619A

CN111629619A - Aerosol-generating article with a collapsible heat source

Info

Publication number: CN111629619A
Application number: CN201980009917.9A
Authority: CN
Inventors: D·库亨; A·普里莫
Original assignee: Philip Morris Products SA
Current assignee: Philip Morris Products SA
Priority date: 2018-02-16
Filing date: 2019-01-29
Publication date: 2020-09-04
Also published as: EP3752015B1; RU2020127220A; WO2019158353A1; EP3752015A1; JP7381473B2; KR20200119799A; JP2021514179A; US20210052011A1; BR112020013396A2

Abstract

The present invention provides an aerosol-generating article (100) having a proximal end (102) and a distal end (104), the aerosol-generating article comprising: an inner tubular member (105) having a mouthpiece end (107) and an opposite heat source end at a distal end of the aerosol-generating article; and an outer tubular element (130) extending from the proximal end of the aerosol-generating article towards the distal end thereof. The inner tubular element comprises an inner packaging sheet (109) defining the following in a coaxial arrangement: a combustible heat source (115) located towards a distal end of the aerosol-generating article; an aerosol-forming substrate (120) downstream of the combustible heat source; and a void space (125) generally between the aerosol-forming substrate and the mouth end. The outer tubular member typically defines at least a mouth end and a void space of the inner tubular member and terminates downstream of the heat source. The inner packaging sheet comprises a pre-distorted portion (109b) at least in the area delimiting said void space. The arrangement is arranged to: the distal end comprising the combustible heat source and the aerosol-forming substrate is readily slidable relative to the outer tubular member from an extended position having a first article length (L1) to a retracted position having a second article length (L2) less than the first article length and in which the void space is at least partially collapsed to an axially contracted configuration.

Description

Aerosol-generating article with a collapsible heat source

Technical Field

The present invention relates to an aerosol-generating article having a collapsible heat source for heating an aerosol-forming substrate.

Background

Aerosol-generating articles in which tobacco is heated without burning have been proposed in the art. One purpose of such "heated" aerosol-generating articles is to reduce certain smoke constituents of the type produced by the combustion and pyrolytic degradation of tobacco in conventional cigarettes. In one known type of heated aerosol-generating article, an aerosol is generated by transferring heat to a combustible heat source, for example a tobacco-containing aerosol-forming substrate. The aerosol-forming substrate may be located downstream of the combustible heat source. An outer wrapper of the aerosol-generating article may be used to enclose the aerosol-forming substrate and at least a portion of the combustible heat source. During use, volatile compounds are released from the aerosol-forming substrate by heat transfer from the combustible heat source and become entrained in air drawn from the tip at which the heat source is located through the heated aerosol-generating article to the mouth end. As the released compound cools, the compound condenses to form an aerosol.

Since combustible heat sources are difficult to extinguish and may burn for longer than the time for which the aerosol-forming substrate is exhausted, it is desirable to provide an aerosol-generating article which can cover the combustible heat source to dispose of the aerosol-generating article. Arranging the outer wrapper sheet to include an internal recess into which the combustible heat sources may be introduced is one way of achieving this. It is also known in the art to include a series of apertures to create a zone of weakness in the aerosol-generating article to assist its collapse. However, this approach introduces additional air pathways that may be detrimental to aerosol delivery.

WO 2017/115196 discloses an aerosol-generating article having a collapsible structure to retract a heat source into an internal "void space". The disclosed structure comprises an inner tubular member comprising, in order from a distal tip towards a proximal mouthpiece end: a heat source, an aerosol-generating substrate, a first diffuser element, a void space, a second diffuser element and an aerosol-cooling element. The inner tubular member is retained within a tubular body that includes a mouthpiece filter element. The outer wrap sheet may be adhered at the joint of the inner tubular member and the tubular body to retain the inner tubular member within the tubular body. The inner tubular member includes a weakened area whereby the tip may collapse into the void space within the tubular body.

It is desirable to provide an aerosol-generating article having a structure comprising a region of weakness. It is desirable to provide an aerosol-generating article that avoids creating an alternative air path that is detrimental to aerosol delivery. Furthermore, there is a need to provide an aerosol-generating article which can be manufactured using existing manufacturing processes and which can be produced at existing production speeds.

Disclosure of Invention

According to one aspect of the present invention, there is provided an aerosol-generating article having a proximal end and a distal end. An inner tubular element is provided comprising an inner packaging sheet defining a combustible heat source located towards a distal end of the aerosol-generating article. The inner wrapper sheet also defines an aerosol-forming substrate positioned downstream of the combustible heat source. The combustible heat source and aerosol-forming substrate are provided in a coaxial arrangement. The aerosol-generating article further comprises an outer tubular element defining at least a portion of the inner tubular element. The inner packaging sheet comprises a pre-twisted portion that enables the inner tubular member to be deformed such that the distal end of the inner tubular member is slidable relative to the outer tubular member.

Advantageously, the pre-twisted portion provides a convenient mechanism for collapsing the aerosol-generating article and may be incorporated into existing production lines with only minor modifications and without affecting line speed. Another advantage of the pre-twisted portion is that weak zones are created that enable collapsing deformation without introducing additional air paths.

In some embodiments, the aerosol-generating article may comprise a mouthpiece filter at the proximal end, and the mouthpiece end of the inner tubular element may be mounted to the mouthpiece filter. In some embodiments, the combustible heat source may be a carbonaceous heat source. The aerosol-forming substrate may comprise tobacco.

In some embodiments, the aerosol-generating article may comprise a void space between the aerosol-forming substrate and the mouth end. In the extended position, the first transfer element may be located between the aerosol-forming substrate and the void space. The aerosol-generating article may further comprise a second transfer element, the second transfer element being separated from the first transfer element by the void space in the extended position. Where first and second transmission elements are provided, these elements may abut one another when the void space collapses to an axially contracted configuration. The outer tubular member may extend from the proximal end of the aerosol-generating article towards the distal end thereof and define at least a mouth end of the inner tubular member and the void space and terminate downstream of the heat source. The pre-distorted portion may be at least in a region that defines the void space. In certain embodiments comprising a void space, the inner tubular member is slidable from an extended position having a first article length to a retracted position having a second article length less than the first article length, and in the retracted position the void space is at least partially collapsed to an axially collapsed configuration. When in the retracted position, the second article length may be about 80% of the first article length or less than the first article length. When in the retracted position, the second article length may be about 70% of the first article length or less than the first article length.

The outer tubular member may terminate at or downstream of the aerosol-forming substrate.

In some embodiments, the outer tubular member may comprise an outer wrapping sheet. The outer wrap sheet may be joined to the inner tubular member only at the mouth end of the inner tubular member. For the first circumferential wrapping, the outer wrap sheet may be joined to the inner tubular member at the mouth end of the inner tubular member. For the second package, the outer packaging sheet may be joined to itself. The outer packaging sheet may be joined to itself along substantially its entire length. The outer packaging sheet may be adhesively bonded to the inner packaging sheet. The outer packaging sheet may be adhesively bonded to itself.

The portion of the inner tubular element downstream of the pre-twisted portion may be rotationally offset relative to the portion of the inner tubular element upstream of the pre-twisted portion. The rotational offset may be 5 degrees or more. The rotational offset may be 15 degrees or more. The rotational offset may be 45 degrees or more. When in the retracted position, the second article length may be about 90% of the first article length or less than the first article length.

An outer wrapper for use in the manufacture of an aerosol-generating article is also disclosed. The outer packaging sheet comprises a first edge and a second opposing edge substantially parallel to the longitudinal axis of the aerosol-generating article. The width of the sheet is defined by a first edge and a second opposite edge, the width being at least equal to twice the circumference of the inner tubular member. The overwrap sheet has a glue pattern deposited thereon, the glue pattern including a first region including a strip of adhesive extending substantially perpendicularly from a first edge toward a second edge. The tape extends from the first edge toward the second edge for a distance at least equal to the circumference of the inner tubular member. When wrapped around the inner tubular element starting from the first edge, the adhesive tape forms an adhesive bond between the outer wrap sheet and the inner tubular element only at the mouth end of the inner tubular element. The glue pattern further comprises a second zone comprising a glue zone extending from the point where the band ends to the second edge along substantially the entire length of the outer wrapper sheet. The glue pattern in the second zone forms an adhesive bond between the first package and any subsequent packages of the outer package sheet substantially along their entire length.

Advantageously, the specific glue pattern on the outer wrapping sheet provides both a secure connection of the inner tubular element to the outer tubular element, and an unglued inner region that collapses the inner tubular element, as well as structural rigidity around the unglued portion.

According to one aspect of the present invention, there is provided a method of manufacturing an aerosol-generating article having a proximal end and a distal end. The method comprises providing an inner tubular member comprising an inner packaging sheet defining a combustible heat source located towards a distal end of an aerosol-generating article. The inner wrapper sheet also defines an aerosol-forming substrate downstream of the combustible heat source. The combustible heat source and aerosol-forming substrate are provided in a coaxial arrangement. The inner wrapper sheet comprises a pre-distorted portion. The method further comprises overwrapping at least a portion of the inner tubular member with an overwrap sheet. Thus, the distal end of the inner tubular member can slide relative to the outer tubular member.

In certain embodiments, the inner wrapper sheet also defines a void space between the aerosol-forming substrate and the mouth end, also arranged coaxially therewith.

Overwrapping the inner tubular element may comprise, starting from the first edge of the overwrap sheet, adhesively bonding the overwrap sheet to the inner tubular element only at the mouth end of the inner tubular element for the first circumferential wrap. The overwrap may further comprise second wrapping the overwrap sheet along substantially the entire length of the overwrap sheet to form the outer tubular element. The outer tubular element may extend from the proximal end of the aerosol-generating article towards the distal end thereof. Where the inner tubular member comprises a void space, the outer tubular element may define at least a mouth end of the inner tubular element and the void space. The outer tubular member may terminate downstream of the heat source. The distal end comprising the combustible heat source and the aerosol-forming substrate is slidable relative to the outer tubular member from an extended position having a first article length to a retracted position having a second article length. The second article length is less than the first article length. Sliding the distal end from the extended position to the retracted position at least partially collapses the void space to an axially collapsed configuration.

The method may comprise providing a mouthpiece filter at a proximal end of the aerosol-generating article. The mouth end of the inner tubular member may be mounted to a mouth filter.

The method can include applying a pre-twist to the inner tubular member during the over-wrapping process. The overwrapping may comprise applying an overwrapping sheet using a rotating roller, which may comprise rolling the inner tubular element through an extrusion between the rotating roller to which the overwrapping sheet is temporarily attached and a fixed guide, the overwrapping sheet being wrapped around the inner tubular element and adhered thereto during passage of the inner tubular element through the extrusion. The distal end of the inner tubular member, which is not overwrapped, can be rotated at different rates to the more proximal end of the inner tubular member defined by the overwrap sheet, thereby causing distortion in the inner wrapping sheet of the inner tubular member. The pre-twist may be applied to the inner tubular member at a twisting station prior to the over-wrapping procedure.

The method may comprise back-to-back manufacturing a pair of aerosol-generating articles, comprising providing a single mouthpiece filter element having first and second ends corresponding to the first and second mouthpiece filters initially combined. The method may comprise providing an inner tubular element comprising providing first and second inner tubular elements mounted to respective first and second ends of a single mouthpiece filter element. The overwrapping of the first inner tubular member and the second inner tubular member can be performed simultaneously. The outer package may use a single outer package sheet. The outer wrapper sheet may be symmetrical about the centre of the mouthpiece filter element. The outer wrapper sheet may form the first outer tubular element and the second outer tubular element, which are initially joined. The method may comprise severing the bonded outer tubular element and the mouthpiece filter element to separate the bonded article into a first aerosol-generating article and a second aerosol-generating article.

All scientific and technical terms used herein have the meanings commonly used in the art unless otherwise indicated. The definitions provided herein are to facilitate understanding of certain terms used frequently herein.

As used herein, the term "aerosol-generating article" refers to an article comprising an aerosol-forming substrate capable of releasing (e.g. by heating, combustion or chemical reaction) volatile compounds that can form an aerosol.

As used herein, the term "aerosol-forming substrate" is used to describe a substrate capable of releasing volatile compounds that can form an aerosol. The aerosol generated from the aerosol-forming substrate of the aerosol-generating article according to the present invention may be visible or invisible and may comprise vapour (e.g. fine particles of a substance in the gaseous state, which is typically a liquid or solid at room temperature) as well as droplets of gas and condensed vapour.

As used herein, the term "sheet" means a layered element having a width and length greater than its thickness.

The terms "upstream" and "downstream" refer to the relative positions of elements of an aerosol-generating article described with respect to the direction of the inhalation air flow as it is drawn through the body of the aerosol-generating article from the distal tip to the mouthpiece end. In other words, "downstream" as used herein is defined with respect to airflow during use of the smoking article or aerosol-generating article, wherein the mouth end of the article through which air and aerosol are drawn is the downstream end. The end opposite the mouth end is the upstream end.

The words "preferred" and "preferably" refer to embodiments of the invention that may provide certain benefits under certain circumstances. However, other embodiments may be preferred under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, and is not intended to exclude other embodiments from the scope of the disclosure, including the claims.

In the description and claims of this specification, the words "comprise" and "comprise", and variations of the words, comprise and/or comprise, mean "including but not limited to", and are not intended to (and do not) exclude other groups, additives, components, integers or steps. In the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

Drawings

Figure 1 is a schematic view of an exemplary aerosol-generating article;

fig. 2A and 2B are schematic views of the exemplary aerosol-generating article of fig. 1 in an extended position and a retracted position, respectively;

FIG. 3 is a schematic view of the first and second bonded inner tubular members prior to overwrapping by the overwrap sheet;

figure 4 is a schematic view of a combined aerosol-generating article prior to separation into a first aerosol-generating article and a second aerosol-generating article;

figure 5 is a schematic side view of the tubular element overwrapped by the overwrap sheet at the overwrapping station; and

figure 6 is a schematic view of a partially wrapped inner tubular member.

The schematic drawings are not necessarily drawn to scale and are presented for illustrative, but not limiting, purposes. The figures depict one or more aspects described in the present disclosure. However, it should be understood that other aspects not depicted in the drawings fall within the scope of the present disclosure.

Detailed Description

Fig. 1 is a schematic view of an exemplary aerosol-generating article 100 extending between a proximal end 102 and a distal end 104. An inner tubular member 105 having a mouthpiece end 107 is provided in the aerosol-generating article 100. An opposing heat source end positioned at the distal end 104 of the aerosol-generating article 100 is also provided. The inner tubular member 105 comprises an inner packaging sheet 109. The inner wrapper sheet 109 defines a combustible heat source 115 located towards the distal end of the aerosol-generating article 100. The inner packaging sheet 109 also defines an aerosol-forming substrate 120 positioned downstream of the combustible heat source 115. The inner packaging sheet 109 also defines a void space 125 between the aerosol-forming substrate 120 and the mouth end 107. The combustible heat source 115, aerosol-forming substrate 120 and void space 125 are provided in a coaxial arrangement. The aerosol-generating article 100 further comprises an outer tubular member 130 extending from the proximal end 102 of the aerosol-generating article 100 towards the distal end 104 thereof. The outer tubular member 130 defines at least the mouth end 107 and the void space 125 of the inner tubular member 105. The outer tubular member 130 terminates downstream of the heat source 115. The inner packaging sheet 109 comprises a pre-distorted portion 109b (see fig. 6) at least in the area delimiting the void space 125. The distal end 104 comprising the combustible heat source 115 and the aerosol-forming substrate 120 is slidable relative to the outer tubular member 130 from an extended position having a first article length (L1, see fig. 2A) to a retracted position having a second article length (L2, see fig. 2B) that is less than the first article length. Sliding the distal end 104 from the extended position to the retracted position at least partially collapses the void space 125 to an axially collapsed configuration.

The aerosol-generating article 100 is also shown to comprise a first transfer element 121a and a second transfer element 121b located within the inner tubular element 105 (see figure 2A). The first transfer element 121a and the second transfer element 121b may be spaced apart from each other when the aerosol-generating article is in the extended position. The first transfer element 121a and the second transfer element 121b are shown at the ends of the void space 125, between the aerosol-forming substrate 120 and the mouthpiece filter 127, respectively. It is also shown that the aerosol-generating article 100 comprises a transfer element 117 located between the combustible heat source 115 and the aerosol-forming substrate 120. A transfer element 117 is defined within the inner packaging sheet 109.

As shown in fig. 6, the pre-twisted portion 109b of the inner packaging sheet 109 may define portions of the respective first and

second transfer elements

121a, 121 b. To extinguish the combustible heat source 115, the distal end 104 comprising the combustible heat source 115 and the aerosol-forming substrate 120 may be slid relative to the outer tubular member 130. As shown in fig. 2A and 2B, the distal end is slidable from an extended position having a first article length (L1 in fig. 2A) to a retracted position having a second article length (L2 in fig. 2B) that is less than the first article length. In the retracted position, the void space 125 is at least partially collapsed to an axially collapsed configuration. The axially contracted configuration may be caused by the application of pressure or force at the distal end of the aerosol-generating article 100, for example, when the aerosol-generating article 100 is "pinched off. It is not necessary that void space 125 completely collapse. Although the transfer elements 121a, 121B are separated in the extended position, in some cases, it may be desirable for the transfer elements 121a, 121B to remain separated when the aerosol-generating article 100 is in the retracted position, as shown in fig. 2B. In other instances, it may be desirable for the first and

second transfer elements

121a, 121b to abut one another (not shown) when the void space 125 collapses to an axially collapsed configuration. It is obvious to the skilled person that the first transfer element 121a and the second transfer element 121b are not essential features; for example, the void space may be distally bounded by the aerosol-forming substrate 120 and proximally bounded by the mouthpiece filter 127. In fact, void space 125 itself is not necessary. It will be appreciated that any axially compressible structure in the inner tubular member will enable the distal end of the inner tubular member to be slidable relative to the outer tubular member for "pinching" off the aerosol-generating article 100.

The pre-twisted portion 109b is a preferred method of creating a zone of weakness to enable the distal end of the inner tubular member to be slidable relative to the outer tubular member, particularly over perforating the inner packaging sheet or cutting slits into the inner packaging sheet, as the pre-twisted portion does not introduce additional air paths within the aerosol-generating article 100. Preferably, the aerosol-generating article 100 is manufactured in a back-to-back manner, as shown in figures 3 and 4. That is, the two aerosol-generating articles 100, 100' are produced integrally and simultaneously before being separated by severing the bonded article from the centre. Figure 3 shows the first inner tubular member 105 and the second inner tubular member 105' prior to overwrapping by the overwrap sheet 135. In a back-to-back configuration, a single mouthpiece filter element 129 may be considered to have first and second ends corresponding to the first and second mouthpiece filters 127, 127 ' initially combined, mounted to the respective proximal ends 102, 102 ' of the first and second inner tubular elements 105, 105 '. The first and second mouthpiece filters 127, 127 'are located downstream of the respective associated void spaces 125, 125'. This advantageously allows for simultaneous overwrapping of the first inner tubular element 105 and the second inner tubular element 105 ' to form the initially bonded first outer tubular element 130 and the second outer tubular element 130 ' using a single overwrap sheet comprising the initially bonded overwrap sheets 135, 135 ' that are symmetric about the centerline 200 of the mouthpiece filter element 129. Once formed, the bonded aerosol-generating article 100, 100 'may be separated by severing the bonded outer tubular element 130, 130' and mouthpiece filter element 129.

The coaxial arrangement of the inner tubular member 105 is best shown in figure 1. The inner tubular member 105 has a mouth end 107 and a heat source end, and comprises an inner wrapping sheet 109 defining the following in a coaxial arrangement: a combustible heat source 115 located towards the distal end 104 of the aerosol-generating article 100; an aerosol-forming substrate 120 downstream of the combustible heat source 115; and a void space 125 between the aerosol-forming substrate 120 and the mouth end 107. The inner packaging sheet 109 comprises a pre-distorted portion 109b at least in the area delimiting the void space 125. The inner tubular element 105 is also shown to comprise a cap 110 at the distal end 104, upstream of the combustible heat source 115. The lid 110 is shown abutting the combustible heat source 115 and being defined by a portion of the inner packaging sheet 109. The removable cover 110 may include a desiccant (e.g., glycerin) to absorb moisture. This extends the life of the components within the inner tubular element 105. The removable cover 110 may be removed by twisting the removable cover 110 to break the portion of the inner packaging sheet 109 adjacent the cover. Removal of the removable lid 110 exposes the front of the combustible heat source 115 to enable ignition of the combustible heat source 115. The combustible heat sources 115 may be carbonaceous heat sources. The aerosol-forming substrate 120 may comprise tobacco.

The outer wrapper sheet 135 comprises a first edge 155a and a second opposing edge 155b that are substantially parallel to the longitudinal axis 150 of the aerosol-generating article 100. The longitudinal axis 150 of the aerosol-generating article 100 extends between the proximal end 102 and the distal end 104 of the aerosol-generating article 100. The first edge 155a and the second opposing edge 155b define a width of the outer wrapper sheet 135 therebetween. The width of the overwrap sheet 135 is at least equal to twice the circumference of the inner tubular element 105 that it will define, such that it can be wrapped at least twice. The proximal 102 and distal 103 ends of the overwrap sheet 135 extend perpendicularly between the first 155a and second 155b edges. It will be appreciated that when a pair of aerosol-generating articles 100 is manufactured back-to-back with the initially joined outer wrapper sheets, the respective proximal ends 102, 102' will be joined at the centre line 200. For simplicity, the remaining description will be directed only to the outer wrapping sheet 135. The outer wrapper sheet 135 'is the same mirror image and like components are indicated by like reference numerals but with a prime (') suffix.

The outer wrapping sheet 135 is shown with an exemplary glue pattern. The glue pattern shown in fig. 3 comprises glue strips in the form of a first glue strip 145a and a second glue strip 145b extending substantially perpendicularly from the first edge 155a towards the second edge 155b for a distance at least equal to the circumference of the inner tubular member 105. In the area of the second transfer element 121b and in the area delimiting it, the first strip 145a forms an adhesive bond between the outer wrapping sheet 135 and the inner tubular element 105. Thus, when wrapped around the inner tubular element starting from the first edge 155a, an adhesive bond is formed only at the mouth end 107 thereof. A second glue strip 145b is similar to the first strip 145a but located more proximally for joining the overwrap sheet 135 to the mouthpiece filter 127. The first strip 145a and the second strip 145b form adhesive strips that bond the outer wrapping sheet 135 to the inner tubular element 105 and the mouthpiece filter 127 only at the mouthpiece end 107. While two

discrete stripes

145a, 145b are shown, it will be understood that other glue arrangements (such as a single stripe and discontinuous drops or lines) are also encompassed by the present description.

The glue pattern is shown to further include a second zone comprising a glue zone 140 extending from the point where the

bands

145a, 145b end to a second edge 155b along substantially the entire length of the overwrap sheet 135 (i.e., from the proximal end 102 to the distal end 103). The glue zone 140 forms an adhesive bond between the first package and any subsequent packages of the outer packaging sheet 135 along substantially the entire length of the outer packaging sheet. While an adhesive is described, the present description includes other methods in the art of joining the outer tubular member 130 to the inner tubular member 105 or to itself. For example, perforation between sheets or the use of fastening tape may be equally effective.

Although the outer tubular element 130 of the aerosol-generating article is shown to terminate downstream of the aerosol-forming substrate 120, it will be apparent to the skilled person that such an arrangement is purely exemplary and that the present description will likewise include an arrangement in which the outer tubular element 130 terminates at the aerosol-forming substrate 120.

The aerosol-generating article 100 may have a length and diameter similar to a conventional cigarette. The second article length L2 may be about 90% of the first article length or less than the first article length. The second article length may be about 80% of the first article length or less than the first article length. The second article length may be about 70% of the first article length or less than the first article length.

The pre-twisted portion 109b of the inner tubular element 105 can include a rotational offset between a portion of the inner tubular element upstream of the pre-twisted portion 109b (subsequently referred to as an "upstream portion") and a portion of the inner tubular element downstream of the pre-twisted portion (subsequently referred to as a "downstream portion"). The rotational offset between the upstream and downstream portions of the inner tubular member can be about 5 degrees or more. The rotational offset between the upstream and downstream portions of the inner tubular member can be about 15 degrees or more. The rotational offset between the upstream and downstream portions of the inner tubular member can be about 45 degrees or more. The pre-twisted portion may be identified by a series of helical grooves and depressions formed in an inner wrapping sheet circumferentially disposed about the inner tubular member. When unwrapped, the series of helical flutes and depressions will comprise a corresponding series of substantially parallel diagonal lines in the inner wrap sheet.

Fig. 5 is a side view of a manufacturing station for applying the pre-twisted portion 109 b. The illustrated overwrap station includes a first rotating drum 220 to which a series of overwrap sheets 135 with a glue pattern applied thereto are temporarily attached, for example by applying a vacuum to hold the unglued side of each sheet 135 to the outer surface of the first rotating drum 220. Each outer wrap sheet 135 is adhered to the inner tubular member 105 at a first edge 155a thereof. As the first rotating drum 220 rotates, each inner tubular member 105 (with outer wrapping sheet 135 attached) is then brought to the fixed guide plate 230. The first rotating drum 220 and the fixed guide plate 230 act as a press 210 and friction between the unwrapped aerosol-generating article, the fixed guide plate 230 and the first rotating drum 220 causes the outer wrapper sheet 135 to wrap around the inner tubular member 105, thereby forming a wrapped aerosol-generating article 100.

The glue pattern shown in figure 3 enables the outer wrapper sheet 135 to be adhered to the inner tubular element 105 and the mouthpiece filter 127 in the first circumferential package. As the overwrap sheet 135 is wrapped around the inner tubular element 105, the adhesive tape comprising the first strip of adhesive 145a and the second strip of adhesive 145b bonds the overwrap sheet 135 to the mouthpiece filter 127 and the inner tubular element 105 at the mouthpiece end 107. Since the upstream portion of the inner tubular element 105 is not overwrapped (because the distal end 103 of the overwrap sheet 135 terminates more proximally), it rotates to the downstream portion of the inner tubular element 105 at a different rate, which causes a twist in the inner wrapping sheet 109 of the inner tubular element 105. The difference in thickness between the portion of the inner tubular member 105 bounded by the outer wrapping sheet 135 and the portion not bounded by it produces a different amount of friction. This difference in friction causes the portion of the inner tubular element not wrapped around any of the outer wrapping sheet 135 to rotate less than the portion bounded by the outer wrapping sheet 135, resulting in a pre-twisted portion 109b that is prone to collapse.

For the second circumferential wrap, once the desired amount of twist has been achieved, the outer wrap sheet 135 is wrapped around the inner tubular element 105. During the second circumferential wrapping, the outer wrapping sheet 135 is wrapped around the unglued portion of the inner tubular element 105. The second glue region 140 forms a second circumferential wrapping of the outer wrapping sheet 135 into a rigid, but still remaining easily collapsible, outer tubular element 130.

After the outer wrapper sheet 135 defines itself for the second time, the aerosol-generating article 100 is formed and may be removed from the press 210 by the second rotating drum 240. While it is preferred to apply the pre-twist to the inner tubular member 105 at the same time as the outer wrapping of the inner tubular member 105, it will be apparent to the skilled artisan that this is not necessary. The pre-twist may be applied at a twist station prior to the overwrap station.

Although the manufacturing process has been described in the context of a single aerosol-generating article 100, it will be apparent to the skilled person that this description will apply, mutatis mutandis, to aerosol-generating articles manufactured in a back-to-back configuration, which may be preferred for process efficiency, so as to be able to produce two articles 100, 100' simultaneously in a single production line. When the aerosol-generating article is manufactured in a back-to-back configuration, the rolled article removed from the extrusion 210 by the second rotating drum 240 will comprise the joined outer tubular elements 130, 130'. In this case, the rolled article may be divided along the centre line 200 by cutting the bonded outer tubular element 130, 130 'and the bonded mouthpiece filter member 129 to produce the first aerosol-generating article 100 and the second aerosol-generating article 100'. This cutting procedure may be performed as part of the overwrapping process, or at a separate cutting station.

While the mouthpiece filter 127 and the mouthpiece filter member 129 have been included in this description, they are not essential to the present invention. Similarly, although the removable cap 110 has been described as a way of retaining the aerosol-forming substrate, the removable cap 110 is not essential to the invention. Similarly, although the transfer element 117 has been described, it is not essential to the invention. Additionally, while the pre-twisted portion 109b has been described as preferably being formed simultaneously during over-wrapping of the inner tubular member 105, this is not essential to the present invention. The pre-distorted portion 109b of the inner wrapper sheet 109 may be applied at a separate distortion station and subsequently over wrapped. While adhesive has been described as one method of securing the outer wrapping sheet 135 to the inner tubular member 105 and itself, this is not essential to the invention and other securing methods, including mechanical securing methods such as perforations or surface features, are included in this description. Although the outer wrapping sheet 135 is described as being adhered to itself along substantially the entire length of the outer wrapping sheet 135, this is not essential to the invention. Adhesion along less than the entire length of the overwrap sheet 135 may still provide the advantages of the present invention.

Features, integers, characteristics, compositions, chemical groups or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The invention is not restricted to the details of any of the foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

1. An aerosol-generating article having a proximal end and a distal end, comprising:

an inner tubular member comprising an inner packaging sheet defining, in a coaxial arrangement:

a combustible heat source located towards a distal end of the aerosol-generating article; and

an aerosol-forming substrate downstream of the combustible heat source; and

an outer tubular member defining at least a portion of the inner tubular member;

wherein the inner packaging sheet comprises a pre-distorted portion;

thereby, the pre-twisted portion enables the inner tubular member to be deformed such that the distal end of the inner tubular member is slidable relative to the outer tubular member.

2. An aerosol-generating article according to claim 1, further comprising a mouthpiece filter at the proximal end, wherein the mouthpiece end of the inner tubular element is mounted to the mouthpiece filter.

3. An aerosol-generating article according to claim 2, further comprising a void space between the aerosol-forming substrate and the mouthpiece end.

4. An aerosol-generating article according to claim 3, wherein the outer tubular element extends from a proximal end of the aerosol-generating article towards a distal end thereof and defines at least a mouth end of the inner tubular element and the void space and terminates downstream of the heat source, and wherein the pre-twisted portion is at least in a region defining the void space.

5. An aerosol-generating article according to claim 3 or claim 4, wherein the inner tubular element is slidable from an extended position having a first article length to a retracted position having a second article length less than the first article length, and in the retracted position the void space is at least partially collapsed to an axially contracted configuration.

6. An aerosol generating article according to claim 5, wherein the second article length is about 90% or less than the first article length, or about 80% or less than the first article length, or about 70% or less than the first article length.

7. An aerosol-generating article according to any one of claims 2 to 6, wherein the outer tubular element comprises an outer wrapper sheet which is joined to the inner tubular element only at the mouth end of the inner tubular element for a first circumferential pack and to itself for a second pack.

8. An aerosol-generating article according to claim 7, wherein for the second package the outer wrapper sheet is joined to itself along substantially its entire length.

9. An aerosol-generating article according to any preceding claim, wherein the portion of the inner tubular element downstream of the pre-twisted portion is rotationally offset by about 5 degrees or more, or about 15 degrees or more, or about 45 degrees or more, relative to the portion of the inner tubular element upstream of the pre-twisted portion.

10. A method of manufacturing an aerosol-generating article having a proximal end and a distal end, comprising:

providing an inner tubular element comprising an inner packaging sheet defining the following in a coaxial arrangement:

an aerosol-forming substrate downstream of the combustible heat source;

wherein the inner packaging sheet comprises a pre-distorted portion; and

overwrapping at least a portion of the inner tubular member with an overwrap sheet, whereby the pre-twisted portion enables the inner tubular member to be deformed such that the distal end of the inner tubular member is slidable relative to the outer tubular member.

11. The method of claim 10, wherein overwrapping the overwrap sheet comprises, for a first circumferential wrap, adhesively bonding the overwrap sheet to the inner tubular element only at the mouth end of the inner tubular element, starting from a first edge of the overwrap sheet; and adhesively joining the first and second wrappers of the outer wrapper sheet substantially along the entire length of the outer wrapper sheet, thereby forming an outer tubular member extending from the proximal end of the aerosol-generating article towards the distal end thereof, the outer tubular member defining at least the mouth end of the inner tubular member.

12. The method of claim 10 or claim 11, wherein pre-twist is applied to the inner tubular element during an over-wrapping process.

13. The method of any one of claims 12, wherein the overwrap process comprises applying the overwrap sheet using a rotating drum.

14. The method according to claim 13, wherein the over-wrapping comprises rolling the inner tubular element through an extrusion between a rotating roller to which the sheet is temporarily attached and a stationary guide plate, the sheet being wrapped around and adhered to the inner tubular element during its passage through the extrusion, wherein a distal end of the inner tubular element, which is not over-wrapped, is rotated at a different rate to a more proximal end of the inner tubular element defined by the over-wrapped sheet, thereby causing a twist in an inner wrapping sheet of the inner tubular element.

15. The method of any one of claims 10 to 14, comprising back-to-back manufacturing a pair of aerosol-generating articles, comprising providing a single mouthpiece filter element having first and second ends corresponding to the first and second mouthpiece filters initially joined, wherein providing an inner tubular element comprises providing first and second inner tubular elements mounted to the respective first and second ends of the single mouthpiece filter element, wherein simultaneously overwrapping the first and second inner tubular elements with a single overwrap sheet that is symmetric about the centre of the mouthpiece filter element to form first and second outer tubular elements initially joined, the method comprising severing the outer tubular element and the mouthpiece filter element, to separate the combined article into a first aerosol-generating article and a second aerosol-generating article.