WO2018162515A1

WO2018162515A1 - Aerosol-generating article and method for manufacturing a rod of aerosol-forming substrate

Info

Publication number: WO2018162515A1
Application number: PCT/EP2018/055528
Authority: WO
Inventors: Tony Reevell
Original assignee: Philip Morris Products S.A.
Priority date: 2017-03-08
Filing date: 2018-03-07
Publication date: 2018-09-13

Abstract

The aerosol-generating article (1) comprises a rod (21,22) of aerosol-forming substrate circumscribed by a wrapper (210). The aerosol-forming substrate comprises a sheet (2) of aerosol-forming substrate, which sheet (2) of aerosol-forming substrate is rolled into a spiral forming the rod (21,22). Also provided is method for manufacturing a rod (21,22) of aerosol-forming substrate

Description

Aerosol-generating article and method for manufacturing a rod of aerosol-forming substrate

The invention relates to an aerosol-generating article and a method for manufacturing a rod of aerosol-forming substrate. In particular, the invention relates to a method for rolling aerosol-forming substrate into a rod and an article comprising such a rod or a portion of the rod.

In conventional cigarettes as well as in aerosol- generating articles where a tobacco substrate is combusted or heated, the substrate is made of a sheet of homogenized or reconstituted tobacco material. The sheet is crimped and then gathered transverse to a longitudinal direction of the sheet material to form a continuous rod.

It would be desirable to have aerosol-generating articles which are more cost efficient to manufacture and a manufacturing process for tobacco rods, which is more cost efficient .

According to the invention there is provided an aerosol- generating article comprising a rod of aerosol-forming substrate circumscribed by a wrapper. The aerosol-forming substrate comprises a sheet of aerosol-forming substrate, which sheet of aerosol-forming substrate is rolled into a spiral forming the rod. Thus, the windings of the rolled rod are not completely overlying each other but are displaced against each other. The displacement is present in a linear direction along the longitudinal axis of the so formed rod. Subsequent windings of the rod comprise a distance between each other. The windings of the spiral in the rod are displaced against each other along a longitudinal axis of the rod . Preferably, a displacement is regular and a distance between neighbouring windings is equal over the length of a rod. A distance between two subsequent windings of the spiral may be in a range between 0.2 millimeter and 4 millimeter, preferably in a range between 0.5 millimeter and 2.5 millimeter, for example 1.5 millimeter.

A diameter of the rod may be between about 5 millimeter and 10 millimeter, preferably between 5 millimeter and 8 millimeter.

A length of the rod may be between 5 millimeter and

25 millimeter, preferably between 8 millimeter and 20 millimeter, for example 15 millimeter.

An aerosol-generating article comprising an aerosol- forming substrate in the form of a sheet of aerosol-forming substrate rolled into a spiral, is more cost efficient than articles comprising crimped sheets. It may even be more cost efficient than comparable articles comprising rolled sheets not in the form of spirals. Rods comprising sheets of aerosol-forming substrate rolled in the form of spirals may be manufactured in a cost efficient manner, in particular if manufactured continuously.

By rolling the sheet of aerosol-forming substrate, the substrate does not need to be crimped for a subsequent gathering. No structuring of the aerosol-forming substrate is required to support a rod forming, in particular a controlled rod forming. The rolling process does not require special preparation of the aerosol-forming substrate for the rolling process. The rolling of the substrate allows the manufacture of reproducible rods of aerosol-forming substrate. The rolling of the sheet in a spiralling manner allows to continuously form a rod. In particular, with a given substrate and given rolling and translation parameters, a reproducible resistance to draw of rods may be achieved. In addition, by varying the rolling parameters denser or less dense rods may be formed.

Depending on the manufacturing process, for example using a holder around which the sheet of aerosol-forming substrate is rolled, a central opening remains after removal of the holder. Such a central opening may facilitate the insertion of a heating element, for example a heater blade, into the aerosol-forming substrate of the rod.

Preferably, the aerosol-generating article is rod-shaped having an equal diameter as the diameter of the rod of aerosol-forming substrate comprised in the article.

The sheet of aerosol-forming substrate may contain tobacco material or may contain a non-tobacco material.

The sheet of aerosol-forming substrate may be a sheet of cellulose material impregnated with nicotine, preferably comprising one or more flavours.

Preferably the sheet of aerosol-forming substrate is a sheet of homogenised tobacco material, preferably comprising one or more aerosol-formers.

An aerosol-forming substrate is a substrate comprising substances, which substances may be volatilized from the substrate upon heating the substrate and which substances may form an inhalable aerosol. Advantageously, the aerosol- forming substrate comprises tobacco material.

As used herein, the term 'homogenised tobacco material' denotes a material formed by agglomerating particulate tobacco .

The aerosol-generating article may comprise further elements, such as for example one or more of the following elements: a filter, an aerosol-cooling element, a support element, a distancing element such as for example a cavity or a hollow tube.

The aerosol-generating article may be a smoking article comprising as aerosol-forming substrate a combustible smokable material and a filter downstream of the rod of combustible smokable material, such as for example a cigarette .

The aerosol-generating article may be a heated aerosol- generating article comprising a combustible heat source and a rod of aerosol-forming substrate downstream of the combustible heat source.

The aerosol-generating article may be a heatable aerosol- generating article, wherein the aerosol-forming substrate of the rod is heated and not combusted to form an aerosol. A heat source for heating the substrate may, for example, be a chemical, electrical or combustible heat source and may be located within, around or upstream of the aerosol-forming substrate .

Such aerosol-generating articles may be used in electrically heated aerosol-generating devices in which the aerosol-forming substrate of the article is heated by an electronic heat source. Volatilized substances may form an aerosol for inhalation.

Preferably, the aerosol-generating article is used in an electronic device for producing aerosol by heating the aerosol-forming substrate.

In certain embodiments, rods for use as rods of combustible smokable material in conventional lit-end smoking articles may have a length of between about 30 mm and about 140 mm. In other embodiments, rods for use as aerosol-forming substrates in heated or heatable aerosol-forming articles may have a length of between about 5 mm and about 20 mm.

Preferably, the rods are of substantially uniform cross- section.

Rods may be manufactured having different dimensions depending upon their intended use.

Sheets of homogenised tobacco material for use in the invention may be formed by agglomerating particulate tobacco obtained by grinding or otherwise comminuting one or both of tobacco leaf lamina and tobacco leaf stems. Alternatively, or in addition, sheets of homogenised tobacco material for use in the invention tobacco may comprise one or more of tobacco dust, tobacco fines and other particulate tobacco by-products formed during, for example, the treating, handling and shipping of tobacco.

Where rods are intended for use as aerosol-forming substrates in heated and heatable smoking articles, sheets of homogenised tobacco material preferably comprise particulate tobacco obtained by grinding or otherwise comminuting tobacco leaf lamina. In certain embodiments, sheets of homogenised tobacco material may have a tobacco content of at least about 40% by weight on a dry weight basis or of at least about 50% by weight on a dry weight basis. In other embodiments, sheets of homogenised tobacco material may have a tobacco content of about 70% or more by weight on a dry weight basis. Where rods are intended for use as aerosol-forming substrate in heated or heatable aerosol-generating articles, the use of sheets of homogenised tobacco material having high tobacco contents advantageously generates aerosols with enhanced tobacco flavour . Sheets of homogenised tobacco material for use in the invention may comprise one or more intrinsic binders, that is tobacco endogenous binders, one or more extrinsic binders, that is tobacco exogenous binders, or a combination thereof to help agglomerate the particulate tobacco. Alternatively, or in addition, sheets of homogenised tobacco material for use in the invention may comprise other additives including, but not limited to, tobacco and non-tobacco fibres, aerosol- formers, humectants, plasticisers , flavourants, fillers, aqueous and non-aqueous solvents and combinations thereof.

Suitable extrinsic binders for inclusion in sheets of homogenised tobacco material for use in the invention are known in the art and include, but are not limited to: gums such as, for example, guar gum, xanthan gum, arabic gum and locust bean gum; cellulosic binders such as, for example, hydroxypropyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose and ethyl cellulose; polysaccharides such as, for example, starches, organic acids, such as alginic acid, conjugate base salts of organic acids, such as sodium-alginate, agar and pectins; and combinations thereof.

Suitable non-tobacco fibres for inclusion in sheets of homogenised tobacco material for use in the invention are known in the art and include, but are not limited to: cellulose fibers; soft-wood fibres; hard-wood fibres; jute fibres and combinations thereof. Prior to inclusion in sheets of homogenised tobacco material for use in the invention, non-tobacco fibres may be treated by suitable processes known in the art including, but not limited to: mechanical pulping; refining; chemical pulping; bleaching; sulfate pulping; and combinations thereof. Sheets of aerosol-forming substrate, in particular sheets of homogenised tobacco material for use in the invention should have sufficiently high tensile strength to survive being rolled to form rods. In certain embodiments non-tobacco fibres may be included in sheets of homogenised tobacco material in order to achieve an appropriate tensile strength.

For example, homogenised sheets of tobacco material for use in the invention may comprise between about 1 % and about 5% non-tobacco fibres by weight on a dry weight basis.

Suitable aerosol-formers and humectants for inclusion in sheets of homogenised tobacco material for use in the invention are known in the art and include, but are not limited to: polyhydric alcohols, such as triethylene glycol, 1 , 3-butanediol and glycerine; esters of polyhydric alcohols, such as glycerol mono-, di- or triacetate; and aliphatic esters of mono-, di- or polycarboxylic acids, such as dimethyl dodecanedioate and dimethyl tetradecanedioate.

In certain preferred embodiments, sheets of homogenised tobacco material comprising one or more aerosol-formers have an aerosol former content of greater than 5% on a dry weight basis. In other preferred embodiments, an aerosol former content is between about 5% and about 30% by weight on a dry weight basis.

A number of reconstitution processes for producing sheets of homogenised tobacco materials are known in the art.

Sheets of homogenised tobacco material for use in the invention are preferably formed by a casting process of the type generally comprising casting a slurry comprising particulate tobacco and one or more binders, possibly comprising one or more aerosol formers onto a conveyor belt or other support surface, drying the cast slurry to form a sheet of homogenised tobacco material and removing the sheet of homogenised tobacco material from the support surface.

For example, in certain embodiments sheets of homogenised tobacco material for use in the invention may be formed from a slurry comprising particulate tobacco, guar gum, cellulose fibres and glycerine by a casting process.

Rods manufactured from sheets of aerosol-forming substrate, in particular of homogenised tobacco material, may have different dimensions such as diameter or length or a grade of spiralling (windings per cm length of the rod) , depending upon their intended use.

For example, the rods may comprise between 1 and 10 windings per cm length of rod, or between 2 and 6 windings per cm length of rod.

Preferably, sheets of aerosol-forming substrate, in particular of homogenised tobacco material for use in the invention have a width of at least about 25 mm. In certain embodiments sheets of aerosol-forming substrate, in particular of homogenised tobacco material for use in the invention may have a width of between about 25 mm and about 300 mm, more preferably between 200 mm and 300 mm.

Preferably, sheets of aerosol-forming substrate, in particular of homogenised tobacco material for use in the invention have a thickness of at least about 50 micrometer.

In certain embodiments, sheets of aerosol-forming substrate, in particular of homogenised tobacco material for use in the invention may have a thickness between 0.1 millimeter and 2 millimeter, preferably between 0.3 millimeter and 1.5 millimeter, for example, 0.8 millimeter.

An aerosol-forming substrate may comprise one or several sheets of aerosol-forming substrates. Preferably, a rod of aerosol-forming substrate comprises one sheet of aerosol- forming substrate, which sheet is rolled into a spiral.

Preferably, the aerosol-forming substrate consists of one or several sheet of aerosol-forming substrate. More preferably, the aerosol-forming substrate consists of one sheet of aerosol-forming substrate. The one or several sheet of aerosol-forming substrate are rolled into a spiral forming the rod. The one or several sheets are rolled in a screw-type manner to form a spiral. Preferably, the rod of aerosol- forming substrate of the article consists of one or several sheets of aerosol-forming substrate that are rolled into a spiral .

If more than one sheet is rolled into a spiral then distances between windings refer to neighbouring windings belonging to different sheets of aerosol-forming substrate.

The aerosol-forming substrate of a rod may comprise two sheets which are rolled into a spiral forming the rod.

The sheets overlap each other partially when being rolled such that the two sheets are arranged in alternating manner in a radial direction of the rod.

The two sheets may be two sheets of aerosol-forming substrate. Preferably, two sheets of aerosol-forming substrate are different sheets of aerosol-forming substrate.

Preferably, two sheets of aerosol-forming substrate differ in at least one of tobacco-, aerosol-, flavour- or nicotine content, sheet thickness or substrate density.

A rod comprising two different sheets provides more variability in the manufacturing of rods. In addition, a manufacturing process for the different sheets may be optimized relating to the different characteristics of the sheets .

The two sheets may be a sheet of aerosol-forming substrate and a sheet of inductively heatable material.

The inductively heatable material, preferably a susceptor material is rolled into the rod together with the sheet of aerosol-forming substrate.

By rolling the susceptor material with the sheet of aerosol-forming substrate an inductively heatable aerosol- forming substrate is formed. The aerosol-generating article comprising such a substrate becomes an inductively heatable article .

The merging of the two sheets, in particular the merging of a susceptor material and an aerosol-forming substrate provides a close contact of the two solids. An inductively heatable rod formed from or comprising such an inductively heatable aerosol-forming substrate may have a good heat distribution and a homogeneous temperature distribution over a cross-section or length of the rod.

Preferably, the sheet of susceptor material is a ferromagnetic tape.

Suitable inductively heatable materials, so-called susceptors include but are not limited to any material that can be inductively heated to a temperature sufficient to generate an aerosol from the aerosol-forming substrate. Preferred susceptors comprise a metal or carbon. A preferred susceptor may comprise or consist of a ferromagnetic material, for example a ferromagnetic alloy, ferritic iron, or a ferromagnetic steel or stainless steel. A suitable susceptor may be, or comprise, aluminium. Preferred susceptors may be heated to a temperature in excess of 250 degrees Celsius. According to the invention, there is also provided a method for manufacturing a rod of aerosol-forming substrate. The method comprises providing a sheet of aerosol-forming substrate and rolling the sheet of aerosol-forming substrate into a rod. Thereby, the rod is continuously formed by varying a position of supply of the sheet of aerosol-forming substrate relative to and along the direction of a longitudinal axis of the rod.

The general advantages of rolling a sheet of aerosol- forming substrate have already been discussed relating to the aerosol-generating article according to the invention and will not be repeated.

By the method according to the invention a rod may not only be formed by rolling the sheet of aerosol-forming substrate but may also continuously be formed into a continuous rod. Through the spiralling of the sheet of aerosol-forming substrate the provision of a continuous sheet of aerosol-forming substrate may create a continuous rod of aerosol-forming substrate. While the rod is formed at one longitudinal end of the rod, the already formed rod may, for example, continuously be wrapped, for example in a paper wrapper. Also a cutting of the continuous rod into discrete rods may be performed continuously.

The holder is a device part and used for rolling the one or several sheet of aerosol-forming substrate. For example, the holder may be removed after the rolling has been completed. In some embodiments the rod may continuously be removed from the holder while the rod is formed.

In addition, depending on how much the position of the supply of the sheet of aerosol-forming substrate relative to the longitudinal axis of the rod is varied, an amount of aerosol-forming substrate per length of the rod may be varied. Thus, a displacement of individual subsequent windings of the rolled sheet may be varied and selected according to a desired rod to be formed.

To support a rolling, a holder may be provided around which the sheet may be rolled. Preferably, the holder is an elongate holder comprising a longitudinal axis. The holder may for example be a pin or a rod. The holder may be stationary, may be rotatable or translatable or may be a combination thereof depending on the rolling mechanism that is chosen for the rolling of the sheet of aerosol-forming substrate .

Preferably, the method comprises supplying the sheet of aerosol-forming substrate to a holder and rolling the sheet of aerosol-forming substrate around the holder. A further step comprises varying an axial position on the holder to which the sheet of aerosol-forming substrate is supplied. The varying of the axial position on the holder is performed in one axial direction only. Preferably, the variation is constant and preferably continuously performed.

A rolling mechanism may be integrated into a holder for the aerosol forming substrate.

A rolling mechanism may be a separate rolling mechanism, separate from the holder. A separate rolling mechanism may roll the sheet of continuous material around the holder, while the holder is not rotated and is preferably kept stationary .

In one variant, the method comprises rotating the holder around its longitudinal axis and keeping an axial position of the sheet of aerosol-forming substrate relative to the holder stationary. A rolling of the sheet is caused by the rotating holder. The spiralling may then be achieved, for example, by a linear translational movement of the holder along its longitudinal axis such that the sheet is supplied to a fresh position on the holder. A spiralling may also be achieved, for example, by an external moving mechanism that is axially moving the formed rod.

Preferably, the method comprises keeping the holder stationary relative to its axial position and letting the sheet of aerosol-forming substrate spirally rolled around the holder slip along the holder in axial direction of the holder .

Advantageously, the method comprises providing a moving device, and generating at least a rotational or a translational movement of the sheet of aerosol-forming substrate by the moving device. Preferably, be the moving device at least a rotational or a translational movement of the continuously manufactured rod is generated. The rotational movement may be a rotation of the rod around its longitudinal axis or a rotation of the rod around a holder. The translational movement of the rod occurs along the direction of the longitudinal axis of the rod or along the longitudinal axis of a holder, respectively.

A rotational movement or a translational movement or a combination of a translational and rotational movement may be realized by various moving devices.

For example, a moving belt may be wound around a portion of the rod. The moving belt contacts the circumference of the rod and thereby causes the rod to follow the movement of the moving belt. The belt may be arranged to cause rotation of the rod. The belt may also be arranged to cause translation of the rod. Preferably, the moving belt is arranged to cause a rotational as well as a translational movement. The position and orientation of the moving belt thereby defines the spiral (e.g. windings per length) that is formed by the spiralled rolling of the sheet of aerosol-forming substrate.

For example, a moving device may comprise guide rollers arranged at the circumference of the rod. The guide rollers, for example two, three or four rollers, may be arranged preferably regularly and equidistantly along the circumference of the rod. Therein, the rotational axis of the rollers are arranged parallel and offset to the longitudinal axis of the rod.

The guide rollers rotate in a counter direction than the rod. Preferably, the rollers press the sheet against the underlying winding of the sheet thereby supporting the forming of a dense rod and preventing the forming of bumps or ripples in the sheet.

The guide rollers may be used to cause rotation of the rod. Preferably, then all or some of the guide rollers are driven rollers. The contact between guide rollers and sheet of aerosol-forming substrate forces the sheet to move in counter direction than the rolling direction of the rollers.

The rollers may be used as transport rollers, transporting the rod into the longitudinal direction of the rollers. This may be achieved, for example, by a structured surface of the rollers which is moving in a longitudinal direction upon rotation of the rollers. Frictional force between roller and rod may cause the rod to be moved in axial direction. A translational movement of the rod may, for example, be achieved by a guide roller in the form of a worm gear.

Preferably, the rollers are used to cause rotation of the rod as well as of a translational movement of the rod in the longitudinal direction.

Preferably, the method comprises circumscribing the rod of aerosol-forming substrate with a wrapper to form a wrapped rod. Preferably, the wrapper is a paper wrapper or a plastics wrapper .

Preferably, the method also comprises severing the wrapped rod into a plurality of discrete rods, for example into single or double-length rods.

Such single or double-length rods are preferably used in the manufacture of aerosol-generating articles according to the invention.

Preferably, the sheet of aerosol-forming substrate is a continuous sheet of aerosol-forming substrate and the rod is a continuous rod manufactured by continuously providing and rolling the continuous sheet of aerosol-forming substrate.

The invention is further described with regard to embodiments, which are illustrated by means of the following drawings, wherein:

Fig. 1 illustrates a spiralling process in a perspective view;

Fig. 2 shows a simplified view of the spiralling rolling process of Fig. 1;

Fig. 3 illustrates the manufacturing of discrete rods from a continuously formed rod;

Fig. 4 shows an aerosol-generating article;

Fig. 5 shows an embodiment for manufacturing rods comprising a spirally rolled sheet of aerosol forming substrate;

Fig. 6 illustrates a spiralling rolling process comprising two sheets. Fig. 1 shows a holder in the form of a rotatable pin 64. While the pin 64 rotates, the sheet of aerosol-forming substrate 2 is spiralled around the pin 64.

In this embodiment the pin 64 may move linearly in the longitudinal direction of the pin 64 corresponding to a transport direction 300 of the rod 21 being formed. Alternatively, the pin may be stationary relative to its axial position and the rod may be moved in axial direction by slipping along the pin by support of an external moving device (not shown) .

A supply direction 100 of the sheet 2, a rotation direction 200 of the rod 21 while being formed and the transport direction 300 of the rod 21 while being formed is indicated with arrows.

The individual windings of the sheet of substrate are displaced by a displacement distance 25 of about 0.5 mm to about 4 mm, for example by about 1 mm to 2 mm as shown in the simplified drawing of the manufacturing process in Fig 2. The displacement distance 25 may be selected depending, for example, on the thickness of the sheet material, the space required by the pin, and the diameter of the rod to be formed .

In Fig. 3 the rod 21 is wrapped with a paper wrapper 210. A cutter 61 cuts the wrapped rod into individual discrete rods 22. Preferably, the discrete rods have a final length of a rod for an aerosol-generating article. The discrete rods 22 may also have a double-length, which may be preferred in the manufacture of double-length articles.

In Fig. 4 an aerosol-generating article 1 comprising a discrete rod 22 as aerosol-forming substrate segment is shown. The discrete rod 22 is arranged at a most downstream end of the article 1. This end of the article is intended to be heated, for example, to be inserted into an electronic device for heating the aerosol-forming substrate thereby generating aerosol.

The article 1 comprises further segments, such as a hollow tube 23, a cavity 24 and a filter element 25.

The filter element 25 is arranged opposite the rod 22 comprising the substrate and at the most upstream end of the article 1.

The hollow tube may, for example, be a hollow acetate tube. The cavity may be an empty cavity, for example created by a hollow cardboard tube. The filter element is a single filter element, for example a cellulose acetate filter plug.

All segments are assembled in an end-to-end position and are wrapped in an article wrapper 26, for example a paper wrapper .

In Fig. 5 an example of a moving device for manufacturing spiralled rods is illustrated. Four guide rollers 65 are arranged at the circumference of the rod 21. The four rollers 65 have a rotational axis parallel to the longitudinal axis of the rod 21. The four rollers 65 rotate in a counter direction than the rod 21. In Fig. 5 the rod 21 rotates anti^¬ clockwise and the rollers 65 rotate clockwise.

The guide rollers touch the rod 21 at its circumference and support the rod forming or make the sheet to be rolled.

The guide rollers press the sheet against the underlying winding of the sheet thereby supporting the forming of a dense rod and preventing the forming of bumps or ripples in the sheet. If the rollers are driven rollers they may cause the rod to rotate. A holder, possibly a rotatable holder where the sheet is rolled around may then be omitted. The guide rollers 65 are preferably also used as transport rollers, transporting the rod 21 into the longitudinal direction of the guide rollers. By using guide rollers, a pin 64 as shown in Fig. 1 does not necessarily have to extend along the length of the rod and does not need to be linearly displaced but may remain in a fixed axial position. Newly supplied sheet then is supported by the pin 64, while the spirally rolled rod 21 is transported by the guide rollers 65. A linear displacement of the rod 21 and by this a narrow or wide spiralling of the sheet may be defined by the axial movement of the rollers 65.

Fig. 6 shows a similar manufacturing method as shown in Fig. 1, however, with two sheets 2,20 supplied simultaneously to the pin 64.

Dimensions of the rod 21 formed and of a displacement of the windings of the rods 21 may be kept the same as for one sheet. The sheets are in alternate manner wound around pin 64.

The sheets 2,20 may be the same type of sheets, for example, two sheets or aerosol-forming substrate, in particular the same type of tobacco sheets. The sheets 2,20 may be different types of aerosol-forming substrate sheets. If different types of sheets of aerosol-forming substrate are used, the sheets preferably differ in an amount of nicotine, in the kind of tobacco or in flavor or in a combination of the afore-mentioned. The sheets 2,20 may also be different sheets. For example, one sheet 2 is an aerosol-forming substrate and the other sheet 20 is a susceptor band, preferably an aluminium or stainless steel foil.

Claims

1. Aerosol-generating article comprising a rod of aerosol- forming substrate circumscribed by a wrapper, wherein the aerosol-forming substrate comprises a sheet of aerosol-forming substrate, which sheet of aerosol- forming substrate is rolled into a spiral forming the rod, wherein windings of the spiral in the rod are displaced against each other along a longitudinal axis of the rod.

2. Article according to claim 1, wherein a distance

between two subsequent windings of the spiral is in a range between 0.2 millimeter and 4 millimeter.

3. Article according to any one of the preceding claims, wherein a diameter of the rod is between 5 millimeter and 10 millimeter, and wherein a length of the rod is between 5 millimeter and 25 millimeter.

4. Article according to any one of the preceding claims, wherein the sheet of aerosol-forming substrate is a sheet of homogenized tobacco material comprising one or more aerosol-formers.

5. Article according to any one of the preceding claims, wherein the aerosol-forming substrate comprises two sheets which are rolled into a spiral forming the rod, wherein the two sheets are two sheets of aerosol- forming substrate, or wherein one of the two sheets is a sheet of aerosol-forming substrate and the other one of the two sheets is a sheet of inductively heatable material .

Article according to claim 5, wherein the two sheets of aerosol-forming substrate differ in at least one of tobacco-, aerosol-, flavour- or nicotine content, sheet thickness or substrate density.

Method for manufacturing a rod of aerosol-forming substrate, the method comprising:

providing a sheet of aerosol-forming substrate;

rolling the sheet of aerosol-forming substrate into a rod, thereby

continuously forming the rod by varying a position of supply of the sheet of aerosol-forming substrate relative to and along the direction of a longitudinal axis of the rod.

Method according to claim 7, comprising

supplying the sheet of aerosol-forming substrate to a holder;

rolling the sheet of aerosol-forming substrate around the holder; and

varying an axial position on the holder to which the sheet of aerosol-forming substrate is supplied.

Method according to claim 8, comprising

rotating the holder around its longitudinal axis and keeping an axial position of the sheet of aerosol- forming substrate relative to the holder stationary.

10. Method according to any one of claims 8 to 9,

comprising keeping the holder stationary relative to its axial position and letting the sheet of aerosol- forming substrate rolled around the holder slip along the holder in axial direction of the holder.

11. Method according to any one of claims 7 to 10,

comprising

providing a moving device, and generating at least a rotational or a translational movement of the sheet of aerosol-forming substrate by the moving device.

12. Method according to claim 11, wherein the moving device is a moving belt wound around a portion of the rod.

13. Method according to claim 11, wherein the moving device comprises rollers arranged at the circumference of the rod .

14. Method according to any one of claims 7 to 13,

comprising

circumscribing the rod of aerosol-forming substrate with a wrapper to form a wrapped rod; and

severing the wrapped rod into a plurality of discrete rods .

15. Method according to any one of claims 7 to 14, wherein the sheet of aerosol-forming substrate is a sheet of homogenised tobacco material comprising one or more aerosol-formers .