WO2024018375A1

WO2024018375A1 - Method for making a continuous web of reconstituted material of plant origin containing inductively heatable metallic elements

Info

Publication number: WO2024018375A1
Application number: PCT/IB2023/057305
Authority: WO
Inventors: Angelo Li Vigni
Original assignee: Comas Costruzioni Macchine Speciali S.P.A.
Priority date: 2022-07-18
Filing date: 2023-07-18
Publication date: 2024-01-25

Abstract

A method for making a continuous web (N) of reconstituted material of plant origin, in particular, tobacco, comprises the steps of releasing a continuous layer (S) onto a conveyor belt (10) movable along a feed direction (L) and combining with the continuous layer (S) a plurality of metallic filaments (F1) oriented longitudinally along the feed direction (L) and disposed alongside each other according to an orderly distribution. The metallic filaments (F1) are laterally spaced from each other, preferably equispaced, so as to define, transversely to the feed direction (L), an alternating succession of zones with the metallic filaments (F1) and zones without the metallic filaments (F1). The continuous layer (S) containing the metallic filaments (F1) is dried.

Description

DESCRIPTION

METHOD FOR MAKING A CONTINUOUS WEB OF RECONSTITUTED MATERIAL OF PLANT ORIGIN CONTAINING INDUCTIVELY HEATABLE METALLIC ELEMENTS

Technical field

This invention relates to a method for making a continuous web of reconstituted material of plant origin, in particular, tobacco, as well as a method for making rod-shaped segments of the smoking article industry from said continuous web. This invention also relates to an article for generating an aerosol.

Background art Known in the prior art are smoking articles which can be heated without burning to generate an aerosol. These smoking articles have a consumable portion, or "plug", comprising strips of tobacco obtained by cutting a web. During use, the plug is heated to generate the aerosol and this is done without burning the tobacco but by heating it to a temperature above a predetermined temperature.

In particular, in the sector addressed by this invention, it is known that the aerosol can be generated by heating the plug inductively, as described in patent application WO95/2741 1 . For this purpose, during the production of the smoking articles, a flat metallic strip is inserted into the plug to extend coaxially for substantially the full length of the plug.

Applying this metallic strip, although it is a well-established practice, still has some disadvantages in terms of structure, functioning and production economics, making its use complex, not entirely satisfactory and hence improvable. Firstly, at a functional level, the strip has a flat shape and is thus not ideal for uniform heating. In effect, in the zone around the middle of it, the thickness of the material it has to heat is equal to the diameter of the plug, whilst at the ends of it, the material to be heated is less thick. As a result, the heat generated inside the plug is not uniform to an optimal degree, thus lowering heating efficiency.

Secondly, the metallic strip constitutes a foreign body with a sharp cutting edge which, if exposed, can accidentally injure the user during use.

Moreover, the metallic strip is difficult to manage during the production process of the smoking article. Indeed, the production of the smoking article involves inserting the metallic strip into the plug during a step in the production process following the crimping/cutting of the tobacco web (inserting it before that would mean crimping or cutting not only a continuous web of tobacco but, at the same time, also a continuous metal strip, which would rapidly wear the crimping or cutting unit. This in turn means considerably complicating the production machinery and higher production costs. In a solution known in the sector concerned and alternative to that described above, metallic particles are dispersed in the mixture (or "slurry") used to make the tobacco web, so as to obtain a paste in which the metallic particles are uniformly mixed.

In the smoking articles made in this way, the heat in the plug is distributed uniformly. Nevertheless, on account of the excessive dispersion and reduced size of the metallic particles, the heating effect is relatively inefficient and not ideal for generating the aerosol.

Moreover, when cutting the tobacco paste, the metallic particles dispersed therein tend to accelerate wear of the means used to cut the continuous tobacco rod.

In this context, the technical purpose of this invention is, therefore, to provide a method for making a continuous web of reconstituted material of plant origin, in particular, tobacco, a method for making rod-shaped segments of the smoking article industry from said continuous web, as well as an aerosol generating article to overcome the above-mentioned disadvantages of the prior art. Aim of the invention

In particular, the aim of this invention is to provide a method for making a continuous web of reconstituted material of plant origin, in particular, tobacco, a method for making rod-shaped segments of the smoking article industry from said continuous web, as well as an aerosol generating article to allow the plug to be heated in an optimum and efficient manner.

A further aim of this invention is to provide a method for making a continuous web of reconstituted material of plant origin, in particular, tobacco, a method for making rod-shaped segments of the smoking article industry from said continuous web, as well as an aerosol generating article to increase the reliability of the machinery used for the production of the smoking articles. These aims are substantially achieved by a method for making a continuous web of reconstituted material of plant origin, in particular, tobacco, a method for making rod-shaped segments of the smoking article industry from said continuous web, as well as an aerosol generating article, comprising the technical features set out in claims 1 , 10 and 14 and/or in one or more of the claims dependent thereon.

Brief description of the drawings

Further features of the invention and its advantages are more apparent in the detailed description of preferred but non-exclusive embodiments of a method for making a continuous web of reconstituted material of plant origin, in particular, tobacco, a method for making rod-shaped segments of the smoking article industry from said continuous web, as well as an aerosol generating article.

The description is set out below with reference to the accompanying drawings which are provided solely for purposes of illustration without restricting the scope of the invention and in which:

- Figure 1 shows a schematic view of an embodiment of a plant for implementing the methods according to this invention;

- Figures 2A-2B show respective schematic views of a detail of the embodiment of the plant of Figure 1 ;

- Figure 3A shows a schematic view of another detail of the embodiment of the plant of Figure 1 , in a first embodiment;

- Figure 3B shows a schematic view of the detail of Figure 3A, in a second embodiment;

- Figures 4A-4B show respective views of an embodiment of an article comprising an aerosol generating segment according to this invention;

- Figures 5A-5F show possible different example embodiments of an aerosol generating segment according to this invention. The respective embodiments of the method for making a continuous web of reconstituted material of plant origin, in particular, tobacco, and of the method for making rod-shaped segments of the smoking article industry from said continuous web will now be described with reference to a plant used to implement them, denoted by the numeral 1 in Figures 1 -3.

Detailed description of preferred embodiments of the invention

According to the invention, the method for making a continuous web N of reconstituted material of plant origin is implemented using "slurry" technology, that is to say, based on a step of releasing a continuous layer S onto a conveyor belt 10 movable along a feed direction L.

The continuous layer S is formed of a mix I in liquid or semi-liquid form and comprising the reconstituted material.

In this description, the term "reconstituted material" is used in particular to mean a tobacco based plant material. It is specified, however, that the method of the invention can also be implemented with a generic plant fibre material, alternative to tobacco and suitable for use in aerosol-generating smoking articles.

The mix I is made from solid components of the aforesaid material of plant origin, shredded and mixed with one or more other solid and/or liquid components such as, for example, water, glycerine, cellulose fibres and guar gum. The mix I has a predetermined percentage by weight of liquid such as to give the mix a liquid or semi-liquid consistency suitable for application using nozzles typical of slurry technology, preferably between 60% and 90%.

For this purpose, as shown in Figure 1 , the plant 1 comprises a mix feed unit 30 for delivering the mix I to the conveyor belt 10. In particular, the mix feed unit 30 may comprise a mixer 31 connected to a nozzle 32 configured to deliver the mix I to the conveyor belt 10 in order to form the aforesaid continuous layer S on the top surface of the conveyor belt 10. Preferably, the continuous layer has a constant thickness of between 0.1 and 0.3 mm, more preferably, equal to approximately 0.2 mm. In addition, the continuous layer S preferably has a width of between 30 cm and 150 cm and/or corresponding to a multiple of (preferably between 3 and 10 times, for example 5 times) the width of a strip suitable for forming a continuous rod. For this reason, the continuous web MW of multiple width, obtained by drying the continuous layer, is then subdivided into a plurality of webs SW of single width, in particular between 6 cm and 30 cm, more preferably between 10 cm and 13 cm, each suitable for making a respective continuous rod by gathering the web and wrapping it in a paper tube defining the rod. In a preferred solution, the multiple continuous web MW is wound on a roll, transferred, if necessary, and then unwound to be cut into singlewidth strips SW which can be re-wound and sent to respective forming units for forming the continuous rods or directly processed in parallel in a multiple rod machine.

Thus, the term "multiple" is used to indicate the number of webs (whose width is suitable for making one rod each), into which the web leaving the dryer is then subdivided, that is to say, the ratio between the widths of the webs.

According to the invention, the method also comprises a step of combining with the continuous layer S a plurality of metallic filaments F1 oriented longitudinally along the feed direction L and disposed alongside each other according to an orderly distribution. Preferably, the metallic filaments F1 are straight and parallel to each other. Preferably, the metallic filaments F1 are parallel to the feed direction L.

The metallic filaments Fl are laterally spaced from each other, preferably equispaced, so as to define, transversely to the feed direction L, an alternating succession of zones with the metallic filaments F1 and zones without the metallic filaments F1 .

The expression "metallic filaments” is used, preferably, to mean thread-like elements made of metal and having a full cross section.

In particular, the metallic filaments of this invention are suitable for induction heating by generating eddy currents or loss by magnetic hysteresis. For this purpose, the metallic filaments may be made of steel. Alternatively, the metallic filaments may be made of nickel. Alternatively, the metallic filaments may be bicomponent elements consisting of an inner core of steel and an outer sheath of nickel, or vice versa. Alternatively, the metallic filaments may be bicomponent strands or straps, for example consisting of a steel wire and a nickel wire coupled to each other. Preferably, the metallic filaments F1 have a cross section that is circular, elliptic or polygonal, for example, square or rectangular.

According to an aspect of this invention, the metallic filaments F1 have a constant thickness along their length. Preferably, the metallic filaments F1 have a thickness of between 0.04 mm and 0.08 mm. More preferably, the metallic filaments Fl have a thickness of between 0.05 mm and 0.074 mm and, still more preferably, approximately 0.06 mm.

According to an aspect of this invention, the metallic filaments F1 have a constant width. Preferably, and in particular where the transverse cross section of the filaments has a flattened shape, the metallic filaments F1 are between 0.05 mm and 0.50 mm in width. Still more preferably, the metallic filaments F1 are between 0.15 mm and 0.35 mm in width.

Preferably, also, there are more than 5 metallic filaments Fl , more preferably between 5 and 50. In other words, the method comprises combining the continuous layer S with between 5 and 50 metallic filaments F1 for each single width web suitable for making a respective rod (hence between 6 cm and 30 cm in width). In other words, the method comprises combining the continuous layer S with a number of metallic filaments F1 equal to a multiple of a number greater than 5 and preferably between 5 and 50. For example, in the case of an initial web MW between 30 cm and 150 cm in width, equal to 5 times a single width web SW suitable for making a respective rod, there are more than 25 metallic filaments F1 , preferably between 25 and 125 (it is not strictly necessary for the number to be an exact multiple but only that its value be substantially equal to the multiple. That way, once the multiple continuous web MW has been divided into single webs SW (substantially equal to each other in width) suitable for making respective rods, each single web SW contains between 5 and 25 metallic filaments F1 .

Preferably, the metallic filaments F1 contained in each web single width web SW (suitable for making a respective rod) define a total transverse metallic surface area of between 0.10 mm² and 0.50 mm², this surface area corresponding to the total surface area of the metallic section of the corresponding end article. More preferably, the metallic filaments F1 define a total transverse metallic surface area of between 0.15 mm² and 0.40 mm² and, still more preferably, between 0.20 mm² and 0.35 mm². Obviously, considering the initial multiple width web MW, this surface area must be multiplied by that multiple. Advantageously, as will become clearer as this description continues, this technical feature allows optimal and efficient heating of the end article during the use thereof.

For this purpose, the plant 1 comprises a feed unit 20 for feeding the metallic filaments F1 , for example, provided with a plurality of spools 21 and with dispensing means 22 configured to unwind the metallic filaments F1 from the spools 21 and to release them longitudinally along the conveyor belt 10. Alternatively, the filaments F1 may be obtained by in-process cutting of a single metallic tape.

The conveyor belt 10 may also comprise retaining elements (not illustrated in the accompanying drawings) configured to hold the metallic filaments F1 on the conveyor belt 10 along the feed direction L so the metallic filaments F1 remain in the predetermined arrangement.

Preferably, the retaining elements comprise a plurality of magnetized elements, integrated in or fixed to, the conveyor belt 10 or, alternatively, movable along the feed direction L (for example, via magnetized discs whose arrangement-spacing corresponds to the transverse arrangementspacing of the filaments) and configured to magnetically engage (attract/repel) the respective metallic filaments F1 .

According to an aspect of this invention, the step of combining the metallic filaments F1 with the continuous layer S may be carried out by disposing the metallic filaments F1 on a surface zone of the continuous layer S. If this method is used, the metallic filaments F1 may be only partly integrated in the continuous layer S.

Alternatively, the step of combining the metallic filaments F1 with the continuous layer S may be carried out by embedding the metallic filaments F1 in the continuous layer S.

In an example, illustrated in Figures 1 and 2A-2B, the metallic filaments F1 may be placed on the conveyor belt 10 upstream of the mix feed unit 30, which embeds the metallic filaments F1 as the mix is dispensed on the conveyor belt 10.

In another example, not illustrated, the metallic filaments F1 may be released onto the continuous layer downstream of the mix feed unit 30 and then inserted into the continuous layer.

In another example, not illustrated, the feed unit 30 that feeds the mix may comprise first mix dispensing means, which are operatively disposed upstream of the feed unit 20 that feeds the metallic filaments F1 and which are configured to deliver a first continuous layer S of mix, and second mix dispensing means, which are operatively disposed downstream of the feed unit 20 that feeds the metallic filaments F1 and which are configured to deliver a second continuous layer S of mix. In other words, the metallic filaments F1 are deposited on the surface zone of the first continuous layer S of mix and then covered by the second continuous layer S so as to embed the metallic filaments F1 in substantially sandwich-like manner. Preferably, the metallic filaments F1 are continuous filaments.

Alternatively, the step of combining the metallic filaments F1 with the continuous layer S may be carried out using discrete metallic filaments F1 , in particular, between 10 mm and 100 mm in length, and releasing successive metallic filaments F1 at a predetermined spacing from each other. Preferably, the discrete metallic filaments F1 are obtained by in- process cutting of continuous metallic filaments F1 unwound from one or more spools 21 .

Advantageously, as will become clearer as this description continues, this technical feature has a twofold advantage which is, firstly, to protect the transverse cutting tools and, secondly, to avoid injuring the user of the end product.

For this purpose, the plant 1 may comprise an accessory cutting unit, not illustrated, preferably integrated in the feed unit 20 that feeds the metallic filaments F1 and configured to cut the metallic filaments F1 at regular intervals so as to obtain discrete metallic filaments F1 , preferably of the same length.

The discrete metallic filaments F1 are illustrated by way of example in the solution of Figure 3B which is described below.

After obtaining the continuous layer S containing the metallic filaments F1 , the method comprises a subsequent step of drying the continuous layer S containing the metallic filaments F1 so as to obtain a dry, multiple width continuous web MW.

For this purpose, the plant 1 comprises one or more dryers 40 disposed in series along the feed direction L of the conveyor belt 10. The use of several dryers disposed in series allows optimizing the process control conditions (temperature, humidity) of the step of drying.

At a functional level, the continuous layer S moves through one or more drying spaces defined by respective dryers 40 for a drying time determined as a function of a plurality of operating parameters such as, for example, the composition of the mix I, the thickness of the continuous layer S, the temperature profile of each dryer 40 and the desired humidity percentage for the continuous web N. When the step of drying is over, the aforesaid continuous web MW containing the metallic filaments F1 is completely formed.

Preferably, uneven thickness at the metallic filaments F1 is smoothed out by levelling the continuous layer S. In a different solution, uneven thickness at the metallic filaments F1 is smoothed out by levelling the continuous web MW.

For these purposes, a laminating process may be provided. The invention thus provides a web (S; MW; SW) intended for the production of an aerosol generating article formed of a continuous layer of plant origin having, embedded in its thickness, a plurality of metallic filaments F1 oriented longitudinally along the web and disposed alongside each other according to an orderly distribution; the filaments F1 are laterally spaced from each other, preferably equispaced, so as to define, transversely to the web, an alternating succession of zones with the filaments F1 and zones without the filaments F1.

Described below is the method for making rod-shaped segments B2 of the smoking article industry, with reference to the plant 1 used to implement it. The method comprises a step of feeding a dried, single width, continuous web SW, obtained by longitudinally cutting a dried, multiple width, continuous web MW made using the method described above.

It is nevertheless evident that the web that is processed by crimping or cutting may be the entire web MW which leaves the dryer.

The method then comprises a step of crimping and/or cutting the continuous web SW along parallel longitudinal lines. For this purpose, the plant 1 comprises a cutting or crimping unit 50 provided with cutting tools 51 , such as, for example, rotary blades or rollers with circumferential crests running alongside each other and configured to crimp and/or cut the continuous web N. According to known technology, crimping or cutting is done using different rollers, for crimping or cutting respectively, whose outer profile is configured according to the intended purpose.

The step of crimping/cutting is illustrated by way of example in Figures 1 and 3A/3B. Considered below is the solution in which the single width web SW is cut into strips; the same description, however, also applies to the solution in which the web is crimped, which differs from cutting in that the web is scored along parallel, longitudinal lines (defining zones of weakness suitable for subsequently gathering the web into a circular shape) but without dividing it into strips.

Preferably, the continuous web SW is cut into strips T along the aforesaid parallel, longitudinal lines which, according to the invention, are disposed at the zones without the metallic filaments F1 .

Advantageously, this technical feature allows the cutting tools 51 to work in optimum manner and protects the cutting tools 51 . In effect, the cutting tools 51 come into contact only with the dry mix I and not with the metallic filaments F1 , thus preventing damage and/or reducing tool wear.

Preferably, also, the metallic filaments F1 are distributed in the continuous web SW in such a way that at least some of the strips T each comprise one or more metallic filaments F1. Advantageously, as will become clearer as this description continues, this technical feature allows the metallic filaments Fl to be uniformly distributed in the strips T, hence in the aerosol generating segments B2.

Figure 3A shows the solution with continuous metallic filaments F1 , while Figure 3B shows the solution with discrete metallic filaments F1 .

Preferably, the method may comprise a step of detecting to determine a position of the metallic filaments F1 within the initial web SW or within the crimped/cut web. For this purpose, the plant 1 may comprise sensors, not illustrated in the accompanying drawings, operating by radiation and, for example, of the optical/photoelectric, infrared or other suitable type. Advantageously, this step allows detecting the lateral position of the filaments at all times so as to prevent interaction between one or more filaments and the cutting tools 51 and/or to check whether the filaments are excessively misaligned within the respective cut strips.

Preferably, also, the sensors are connected to a control unit operating by feedback on the feed means 20 that feed the metallic filaments Fl so that incorrect positioning of the filaments F1 can be corrected, if necessary.

Preferably, also, in the case of discrete filaments, the sensors can detect the spacing between two successive metallic filaments F1 so as to control the subsequent step of transversely cutting the rod, described below.

The method comprises a subsequent step of gathering the crimped or cut web and wrapping it in a wrapping strip, preferably of paper, to make a continuous rod “B1 ”.

For this purpose, the plant 1 comprises a forming unit 60, in particular provided with a forming beam of known type.

The method comprises a subsequent step of cutting the continuous rod Bl into segments. In other words, the step of cutting the continuous rod B1 into segments allows obtaining the aerosol generating consumable portions or "plugs" for the smoking article.

For this purpose, the plant 1 comprises a secondary cutting unit 70 provided with cutting tools 71 such as, for example, rotary blades configured to transversely cut the continuous rod B1 at regular intervals so as to obtain segments B2 of the same length.

According to an aspect of this invention, with reference to the solution with discrete metallic filaments F1 , the step of cutting the continuous rod B1 into segments is carried out in zones of the continuous rod B1 included between consecutive metallic filaments F1 so that the cutting action does not intersect the metallic filaments F1 .

Advantageously, this technical feature has a twofold advantage. Firstly, cutting the continuous rod B1 in portions included between consecutive metallic filaments F1 allows protecting and preserving the cutting tools 71 , since they operate only on the mix I and not on the metallic filaments F1. Secondly, as explained above, the metallic filaments F1 are contained entirely within the segment B2 so as not to protrude or come out from the axial ends of the article itself.

Preferably, cutting in zones of the continuous rod B1 included between the metallic filaments F1 is carried out by feedback following the step of detecting the position of the metallic filaments F1 within the crimped or cut web.

This invention also relates to an aerosol generating article A comprising a plurality of elements assembled to form a rod-shaped aggregate, the preferred embodiment of which is illustrated by way of non-limiting example in Figures 4A-4B.

In particular, the article A has a proximal end, provided with a filter segment C, and a distal end, provided with an aerosol generating segment B2. The aerosol generating segment B is preferably made using the above described method for making rod-shaped segments B2 of the smoking article industry.

More specifically, there may be a supporting element 200 and/or a cooling element 300 between the filter segment C and the aerosol generating segment B2.

The aerosol generating segment B2 comprises an outer tubular wrapper that is at least partly filled with a plurality of strips T made from the aerosol generating material, wherein at least some of the strips T include one or more metallic filaments F1 susceptible of heating by induction.

According to an aspect of this invention, at least some of the strips T include one or more metallic filaments F1. Advantageously, this feature allows the aerosol generating segment B2 to be uniformly and efficiently heated during use.

Preferably, each metallic filament F1 has a lateral surface that is fully covered by the respective strip T. In other words, each metallic filament F1 is at least laterally embedded in the strip T and is preferably also embedded at the ends (in the case of the discrete filaments). Advantageously, this feature allows further increasing the heating efficiency of the aerosol generating segment B2 during use.

Figures 5A-5F illustrate possible example embodiments of the aerosol generating segment B2 and, in particular, of the strips T making it up.

Figure 5A shows a plurality of strips T, each comprising a single metallic filament F1 inside it.

Figure 5B shows a plurality of strips T in which a first number of strips T comprise a single metallic filament F1 , while a second number of strips T do not comprise any metallic filaments F1 .

Figure 5C shows a plurality of strips T in which a first number of strips T comprise two (or more) metallic filaments F1 , while a second number of strips T do not comprise any metallic filaments Fl .

Figure 5D shows a plurality of strips T in which all the strips comprise two (or more) metallic filaments F1 .

Figure 5E shows a plurality of strips T in which a first number of strips T comprise two (or more) metallic filaments F1 , while a second number of strips T comprise a single metallic filament F1 .

Figure 5F shows a plurality of strips T in which a first number of strips T comprise two (or more) metallic filaments F1 , a second number of strips T comprise a single metallic filament F1 , while a third number of strips T do not comprise any metallic filaments F1 .

In other words, at least some of the strips comprise one or more metallic filaments where the number of such strips may be increased to enhance the heating efficiency.

The invention achieves the preset aims overcoming the drawbacks of the prior art.

In particular, the methods of the invention allow simplifying the plant architecture needed for making inductively heatable smoking articles. This result is achieved using a plurality of metallic filaments inserted in an orderly fashion inside the mix. The methods of the invention also allow obtaining smoking articles that can be heated by induction in an efficient and optimum manner. This result is accomplished thanks to the presence of metallic filaments distributed uniformly within the aerosol generating segment or "plug". The metallic filaments are positioned in such a way as to uniformly heat the innermost portions as well as the peripheral portions of the aerosol generating segment or "plug". Moreover, the number of metallic filaments and/or their total mass are such as to be able to generate the aerosol in an efficient manner.

Claims

1 . A method for making a continuous web (N) of reconstituted material of plant origin, in particular, tobacco, comprising the following steps: releasing a continuous layer (S) onto a conveyor belt (10) movable along a feed direction (L), the continuous layer (S) being formed of a mix (I) in liquid or semi-liquid form and comprising the reconstituted material; combining with the continuous layer (S) a plurality of metallic filaments (F1 ) oriented longitudinally along the feed direction (L) and disposed alongside each other according to an orderly distribution, the metallic filaments (F1 ) being laterally spaced from each other, preferably equispaced, so as to define, transversely to the feed direction (L), an alternating succession of zones with the metallic filaments (F1 ) and zones without the metallic filaments (F1 ); drying the continuous layer (S) containing the metallic filaments (F1 ) to obtain the continuous web (MW).

2. The method according to claim 1 , wherein the metallic filaments (F1 ) are straight and parallel to each other.

3. The method according to claim 2, wherein the metallic filaments (F1 ) have a full cross section.

4. The method according to any one of the preceding claims, wherein the step of combining the metallic filaments (F1 ) with the continuous layer (S) is carried out by embedding the metallic filaments (F1 ) in the continuous layer (S).

5. The method according to any one of claims 1 to 3, wherein the step of combining the metallic filaments (Fl ) with the continuous layer (S) is carried out by disposing the metallic filaments (F1 ) on a surface zone of the continuous layer (S).

6. The method according to any one of the preceding claims, wherein the metallic filaments (F1 ) have a preferably constant thickness of between 0.04 mm and 0.08 mm, preferably between 0.05 mm and 0.074 mm, and still more preferably, approximately 0.06 mm.

7. The method according to any one of the preceding claims, wherein the metallic filaments (F1 ) have a preferably constant width of between 0.05 mm and 0.50 mm, preferably between 0.10 mm and 0.40 mm, and still more preferably between 0.15 mm and 0.35 mm, and/or wherein the number of metallic filaments (F1 ) is equal to a multiple of a number between 5 and 50, the multiple being preferably between 3 and 10 times and, more preferably, 5 times.

8. The method according to any one of the preceding claims, wherein the metallic filaments (F1 ) define a total transverse metallic surface equal to a multiple of a quantity between 0.10 mm² and 0.50 mm², preferably of a quantity between 0.15 mm² and 0.40 mm² and, more preferably, of a quantity between 0.20 mm² and 0.35 mm², the multiple being preferably between 3 and 10 times and, more preferably, 5 times.

9. The method according to any one of the preceding claims, wherein the step of combining the metallic filaments (F1 ) with the continuous layer (S) is carried out using discrete metallic filaments (F1 ), in particular, between 10 mm and 100 mm in length, and releasing successive metallic filaments (F1 ) at a predetermined spacing from each other, the discrete metallic filaments (F1 ) being preferably obtained by in-process cutting of continuous metallic filaments (F1 ) unwound from one or more spools (21 ).

10. A method for making rod-shaped segments (B2) of the smoking article industry, comprising the following steps: feeding a dried continuous web (SW), obtained or obtainable by longitudinally cutting a dried continuous web (MW) made according to any one of the preceding claims; crimping and/or cutting the continuous web (SW) along longitudinal parallel lines; gathering the crimped or cut web (SW) and wrapping it in a wrapping strip, preferably of paper, to make a continuous rod (B1 ); cutting the continuous rod (B1 ) into segments (B2); wherein the step of crimping and/or cutting the continuous web (SW) is carried out in such a way that the longitudinal parallel lines are disposed in the zones without the metallic filaments (F1 ).

1 1 . The method according to claim 10, wherein the continuous web (SW) is cut into strips (T) along the longitudinal parallel lines, and wherein the metallic filaments (F1 ) are distributed in the continuous web (SW) in such a way that at least some of the strips (T) each comprise one or more metallic filaments (F1 ).

12. The method according to claim 10 or 1 1 , comprising a step of detecting the position of the metallic filaments (F1 ) in the continuous web (SW) or the crimped or cut web (SW), the step of detecting preferably generating a signal that identifies the longitudinal and/or transverse position of the metallic filaments (F1 ), respectively, and the signal being used to control the step of cutting the continuous web (SW) longitudinally and/or transversely, respectively.

13. The method according to any one of claims 10-12, when dependent on claim 9, wherein the step of cutting the continuous rod (B1 ) into segments (B2) is carried out in zones of the continuous rod (B1 ) included between consecutive filaments (F1 ) so that the cutting action does not intersect the metallic filaments (F1 ).

14. The method according to any one of claims 1 to 13, wherein the metallic filaments (F1 ) are made from steel and/or nickel.

15. An aerosol generating article (A), comprising a plurality of elements (B2, C) assembled in the form of a rod having a proximal side, provided with a filter segment (C), and a distal side, provided with an aerosol generating segment (B2), wherein the aerosol generating segment (B2) comprises an outer tubular wrapper that is at least partly filled with a plurality of strips (T) made from an aerosol generating material, and wherein at least some of the strips (T) include one or more metallic filaments (F1 ) susceptible of heating by induction.

16. The article according to claim 15, wherein each strip (T) includes one or more metallic filaments (F1 ).

17. The article according to claim 15 or 16, wherein each metallic filament (F1 ) has a lateral surface that is fully covered by the respective strip (T).

18. The article according to any one of claims 15 to 17, wherein the metallic filaments (F1 ) are made from steel and/or nickel.

19. A web intended for the production of an aerosol generating article formed of a continuous layer of plant origin in which a plurality of metallic filaments (F1 ) oriented longitudinally along the web are embedded in its thickness and disposed alongside each other according to an orderly distribution; the filaments (F1 ) being laterally spaced from each other, preferably equispaced, so as to define, transversely to the web, an alternating succession of zones with the filaments (F1 ) and zones without the filaments (F1 ).