WO2025109435A1

WO2025109435A1 - Method and device for making a continuous web of reconstituted plant material

Info

Publication number: WO2025109435A1
Application number: PCT/IB2024/061398
Authority: WO
Inventors: Alessandro Granzotto; Fulvio Pastore
Original assignee: Comas SpA
Current assignee: Comas SpA
Priority date: 2023-11-22
Filing date: 2024-11-15
Publication date: 2025-05-30
Anticipated expiration: 2026-05-22

Abstract

Method for making a continuous web of reconstituted plant material, comprising the step of feeding a continuous layer (S) to a laminating unit (22) having a pair of laminating rollers (201, 202). The continuous layer (S) is subjected to a step of compressing in a continuous process so as to decrease the thickness of the continuous layer (S). The step of compressing is carried out by the pair of rollers (201, 202), feeding the continuous layer (S) along a feed direction (L). A first roller (201) of the two rollers (201, 202) is rotated at a higher speed than the second roller (202) so that the continuous layer (S) adheres to the first roller (201), and the continuous layer (S) exiting the pair of rollers (201, 202) is subjected to a scraping action by the first roller (201) by means of a scraping member (204) cooperating with the first roller (201).

Description

DESCRIPTION METHOD AND DEVICE FOR MAKING A CONTINUOUS WEB OF RECONSTITUTED PLANT MATERIAL.

Technical field

The present invention relates to the field of semi-finished products for making smoking articles or for generating aerosols, and the object thereof is a method for making a continuous web of reconstituted plant material and a device for laminating a continuous layer of reconstituted plant material.

Background art

It is known to make a continuous web of reconstituted plant material by laminating a continuous layer made from a mixture. In particular, the known technologies envisage providing a mixture based on at least one reconstituted plant material and for making a continuous layer, having a first thickness value. The continuous layer is then fed to a laminating unit and processed by at least one pair of opposite rollers, which exert a compression, imparting a second thickness value on the continuous layer, lower than the previous one. Finally, the layer is dried.

In particular, in the field pertaining to the present invention, the continuous layer is conveyed between pairs of consecutive rollers, resulting in being compressed between each pair, receiving a respective thickness calibration. In such a process, in which there is no substantial variation in the internal properties of the material, a single thickness reduction is therefore obtained with a simultaneous increase in the speed of the continuous layer.

In more detail, the belt transits according to the plane arranged substantially tangentially to the rollers of each pair.

In the known solutions, there is the problem of ensuring sufficient reliability in laminating the web since in certain situations, the adhesion of the web to one of the two rollers leads to a deviation in the direction of the web, with breakage thereof, or a possible adhesion to both rollers can lead to a "delamination" of the web (the web can adhere to both rollers, forming a central split in the web itself).

Disclosure of the invention

Therefore, in such a context, it is the technical task of the present invention to provide a method and a device for making a continuous web of reconstituted plant material which are free from the drawbacks of the prior art.

In particular, it is the object of the present invention to provide a method and a device for making a continuous belt of reconstituted plant material capable of having an increased process reliability.

The object is substantially achieved by a method and a device for making a continuous web of reconstituted plant material in accordance with the characteristics set forth respectively in the appended claims 1 and 14 and/or in one or more of the claims dependent therefrom.

In particular, the Applicant has found that by laminating a continuous layer by means of a pair of rollers, in which one roller operates at a higher speed than the other and in which the continuous layer remains adhered to a prefixed roller of the pair of rollers, in combination with a scraping member associated with the adhesion roller of the continuous layer, thus in a "controlled adhesion" regime, an optimal control of the web’s feeding is obtained, avoiding uncontrolled and unwanted adhesion phenomena.

Brief description of drawings

Further features and advantages of the present invention will become more apparent from the indicative, and thus non-limiting, description of a preferred but not exclusive embodiment of a method and a device for making a continuous web of reconstituted plant material, as shown in the accompanying figure 1 which shows a diagrammatic view of a preferred, exemplary and non-limiting embodiment of a machine for making a continuous web of reconstituted plant material with which to implement the aforesaid method and comprising the device according to the present invention.

Detailed description of preferred embodiments of the invention

With reference to the accompanying figures, the reference numeral "1" is used to indicate a machine for making a continuous web of reconstituted plant material for implementing a method for making a continuous web according to the invention. Therefore, the method is described below in an embodiment thereof with reference to the machine 1 used for implementing it.

As can be seen from figure 1 , the machine 1 comprises a device 10 for preparing a mixture “I” based on a reconstituted plant material.

In the present description, the term “in plant material” means that the mixture “I” is obtained from mixing at least one dry plant component, such as tobacco or non-tobacco (rapeseed, straw or other varieties, cellulose or cellulose-derived), with a liquid component, such as water and/or additives, for example.

The device 10 for preparing the mixture "I" is configured to make the aforesaid mixture "I" based on at least one reconstituted plant material and to discharge such a mixture "I" in the form of a continuous layer "S", which has a first thickness value. In the preferred embodiment, the device 10 comprises a containment hopper, diagrammed in figure 1 .

The device 10 for preparing the mixture "I", being of technology known in the state of the art, can take any form technologically suitable for such a purpose. For such a reason, the device 10 for preparing the mixture "I" is not described in detail. However, by way of example it can comprise a "batch" mixer, i.e., suitable for processing discrete quantities of material and for dispensing discrete portions of mixture, associated with a forming device (for example a pair of rollers, called "vertical flattener", and any layering accessories) to transform the discrete portions into a continuous layer. Alternatively, the device 10 for preparing the mixture "I" can operate continuously and comprise, for example, a mixer associated with, or integrated with an extruder device.

In accordance with an aspect of the invention, the continuous layer "S" has a liquid content between 20% and 60%. Preferably, the continuous layer "S" has a liquid content between 25% and 50%. Even more preferably, the continuous layer "S" has a liquid content between 27% and 40%. In other words, the continuous layer is a layer with a dense and pasty consistency, different from a slurry having a moisture percentage greater than 60% and consequently a more liquid consistency (to which the present invention does not refer).

The machine 1 comprises a device 20 for laminating the continuous layer of reconstituted plant material, arranged downstream of the device 10 for preparing the mixture "I". The laminating device 20 is therefore connected downstream of the device 10 for preparing a mixture "I" and is configured to receive the continuous layer "S" from such a device.

Structurally, the laminating device 20 comprises feed means 21 for feeding the continuous layer "S", configured to convey the continuous layer "S" along a feed direction "L", and a laminating unit 22 arranged downstream of the feed means 21 and configured to laminate the continuous layer "S". In particular, the laminating unit 22 is equipped with at least a first laminating stage 200: the at least a first laminating stage 200 comprises at least one pair of laminating rollers 201 , 202 defining a through gap 203 between them and configured to reduce the thickness of the continuous layer "S" when the continuous layer "S" passes between the rollers 201 , 202.

In accordance with a preferred embodiment, shown by way of non-limiting example in figure 1 , the at least a first laminating stage 200 operates along a horizontal feed direction "L". In other words, at least near the pair of rollers 201 , 202 the feed direction "L" is horizontal and the pair of rollers 201 , 202 comprises a roller 202 arranged above the continuous layer "S" and a further roller 201 arranged below the continuous layer "S".

In accordance with an alternative embodiment, not shown, the at least a first laminating stage 200 operates along a vertical or substantially vertical feed direction "L". In other words, at least near the pair of rollers 201 , 202 the feed direction "L" is vertical and the rollers 201 , 202 of the pair of rollers 201 , 202 are arranged horizontally side by side.

In the following of the present description, if not expressly indicated, reference will be made to the embodiment of figure 1 , or to the embodiment in which the at least a first laminating stage 200 operates along the horizontal direction.

In accordance with an aspect of the present invention, a first roller 201 of the pair of rollers 201 , 202 is rotatably operated at a higher rotation speed than the second roller 202 of the pair of rollers 201. Thereby, the continuous layer "S" remains adhered to one of the two rollers 201 , 202, preferably the first roller 201 having a higher speed. In accordance with a preferred and particularly advantageous embodiment, the first roller 201 of the pair of rollers 201 , 202 is the lower roller of the pair of rollers 201 , 202. In other words, the roller 201 of the pair of rollers 201 , 202 operating at a higher speed is the roller 201 arranged below the continuous layer "S". In other words, the roller of the pair of rollers 201 , 202 which is operated at higher speed is the lower roller 201 .

In the embodiment in which the at least a first laminating stage 200 operates along the vertical direction, the roller of the pair of rollers 201 , 202 which is operated at a higher speed is the roller opposite the roller on which the continuous layer (S) is arranged exiting the continuous layer "S" from the pair of rollers 201 , 202.

Preferably, the machine 1 comprises a control unit, not shown, connected at least to the laminating unit 20 and configured to operate, control and adjust the operation of the laminating unit 20. In particular, the control unit is configured to operate, control and adjust the operation of the rollers 201 , 202 of the laminating unit 20.

Preferably, moreover, the at least one laminating stage 200 comprises a respective scraping member 204 adjacent to the first roller 201 and configured to detach the continuous layer "S" from the first roller 201. In other words, the scraping member 204 is associated with the roller 201 operating at a higher speed.

Such a combination of technical features ensures a reliable and efficient lamination. During lamination, the continuous layer "S" remains adherent to one of the two rollers 201 , 202, facilitating the subsequent detachment of the continuous layer "S" by means of the scraping member 204, avoiding the accumulation of residues on both rollers 201 , 202 and ensuring the integrity of the product. Furthermore, the synergy between the roller 201 , 202 operating at a higher speed and the scraping member 204 further contributes to perfecting the detachment of the continuous layer "S" and to safeguarding the physical properties of the web itself.

Preferably, moreover, the at least one laminating stage 200 can comprise a further scraping member 205 ("cleaning scraper") adjacent to the second roller 202 and configured to operate a scraping action on the second roller 202 so as to remove any residues of the continuous layer "S" from the second roller 202 itself. In other words, the further scraping member is configured to operate a mechanical cleaning of the second roller 202.

According to an example, the roller 201 cooperating with the scraping member 204 can have processes and/or surface structure optimized for dynamic cooperation with the scraping member 204, while the other roller 202 (in particular in the absence of the cleaning scraper 205) can optionally intentionally have a non-stick coating.

Alternatively, in particular in the presence of the cleaning scraper 205, both rollers 201 , 202 are made of the same material, preferably metallic, and possibly having the same surface treatment (hardening) so as to optimally resist the scraping action of the respective scraping members 204, 205. The machine 1 then comprises a drying unit 30 arranged, preferably directly, downstream of the laminating unit 22 along the feed direction "L". "Directly" means the exclusion of further operating units configured to process the web, in particular to alter the thickness thereof (any conveyor belts or other conveyors do not fall within the definition of "operating units" in such a sense).

Functionally, it is envisaged to prepare a mixture "I" based on at least one reconstituted plant material and to create by means thereof a continuous layer "S", in which the continuous layer "S" has a first thickness value. The continuous layer "S" is fed to the laminating unit 22 and is subjected to at least one step of compressing by means of a continuous process with rollers so as to impart a second thickness value to said continuous layer “S”, lower than the first thickness value. Preferably, the second thickness value obtained exiting the laminating unit 22 corresponds to the thickness of the continuous layer "S" entering the drying unit 30. In other words, the arrangement of the drying unit 30 directly downstream of the laminating unit 22 makes it possible to keep such a second thickness value unchanged from the laminating unit 22 to the drying unit 30.

In particular, the step of compressing is carried out by the aforesaid at least one pair of laminating rollers 201 , 202 by feeding the continuous layer “S” along the feed direction “L”. In such a process, a first roller 201 of the two rollers 201 , 202 is rotated at a higher speed than the second roller 202 of the same pair of rollers 201 , 202 so that the continuous layer "S" adheres to the first roller 201. The continuous layer "S" exiting the pair of rollers 201 , 202 is then subjected to a scraping action by the first roller 201 by a scraping member 204 cooperating with the first roller 201 .

In an embodiment, the feed direction "L" near the rollers 201 , 202 is horizontal or substantially horizontal.

Alternatively, as indicated above with reference to the embodiment not shown, the feed direction "L" near the rollers 201 , 202 is vertical or substantially vertical. In accordance with a preferred and particularly advantageous embodiment, the first roller 201 of the pair of rollers 201 , 202 is the lower roller of the pair of rollers 201 , 202. In other words, the roller 201 of the pair of rollers 201 , 202 operating at a higher speed is the roller 201 arranged below the continuous layer "S".

In accordance with an aspect of the present invention, the ratio between the rotation speed of the first roller 201 , 301 and the rotation speed of the second roller 202, 302 is between 1 .01 and 2.5.

Finally, the continuous layer "S" exiting the laminating unit 22 is fed, preferably directly, to the drying unit 30 arranged downstream of the laminating unit 22 along the feed direction "L".

In accordance with an aspect of the present invention, in the at least one step of compressing, the continuous layer "S" is not subjected to mixing and/or a reduction in particle size. In other words, during compression, the continuous layer "S" remains substantially uniform and does not undergo significant redistribution or mixing of the internal components thereof. Advantageously, the features and properties of the laminated material are preserved without undesired alterations, such as a reduction in the particle size of the solid component of the continuous layer "S".

In accordance with an aspect of the present invention, the feed means 21 comprise a feed conveyor 23, in particular a belt conveyor, arranged immediately upstream of the first laminating stage 200 of the laminating unit 22 and configured to feed the continuous layer "S" to the first laminating stage 200: the feeding conveyor 23 is configured to cooperate with the pair of rollers 201 , 202 so as to feed the continuous layer "S" to the first laminating stage 200 in a substantially planar and in particular substantially horizontal configuration.

In other words, the feeding of the continuous layer "S" to the laminating unit is operated by supporting the continuous layer "S" by means of the aforesaid belt conveyor 23, which cooperates with the pair of rollers 201 , 202 so as to maintain the continuous layer "S" in a planar configuration. In accordance with an aspect of the present invention, the laminating device 20 further comprises a receiving conveyor 24, in particular a belt conveyor, arranged downstream of the first laminating stage 200: the scraping member 204 is configured to cooperate with the first roller 201 of the first laminating stage 200 and with the receiving conveyor 24 so as to release the continuous layer "S" in a substantially planar configuration on the receiving conveyor 24.

The expression "a substantially planar configuration" means that the continuous layer "S" has a flat, smooth surface without ripples or undulations. In particular, the upper part of the continuous layer "S" appears uniform and does not have curvatures, folds or other irregularities which can cause a non-planar surface.

In accordance with a different embodiment, not shown, the continuous layer "S" is fed to the laminating device 20 in the form of a corrugated web so that when exiting the first laminating stage 200, the thickness of the continuous layer "S" is increased with respect to the thickness of the entering corrugated layer (which accumulates locally in the entrance niche for the pair of rollers of the first laminating stage 200). This preferably applies only to the first stage, as any further laminating stages subsequent to the first one result in a reduction in the thickness of the continuous layer "S".

In accordance with an aspect of the present invention, the laminating unit can comprise a plurality of laminating stages 200, 300 arranged in sequence along the feed direction "L" of the continuous layer "S" and each comprising a respective pair of rollers 201 , 202; 301 , 302. The plurality of laminating stages 200, 300 is configured to progressively compress the continuous layer "S" so as to progressively reduce the thickness of the continuous layer "S" by adopting respective through gaps 203, 303 of progressively decreasing size. Each laminating stage 200, 300 preferably further comprises a respective scraping member 204, 304 adjacent to the first roller 201 , 301 of the corresponding laminating stage 200, 300 and configured to detach the continuous layer "S" from the respective first roller 201 , 301.

Preferably, moreover, the at least one laminating stage 200, 300 comprises a respective further scraping member 205, 305 adjacent to the second roller 202, 302 and configured to operate a scraping action on the second roller 202, 302 so as to remove any residues of the continuous layer "S".

At the functional level, the plurality of laminating stages 200, 300 compresses the continuous layer "S" in stages so as to progressively reduce the thickness of the continuous layer "S" by means of through gaps

203, 303 of progressively decreasing sizes: the continuous layer "S" exiting each pair of rollers 201 , 202, 301 , 302 is kept adherent to the respective first roller 201 , 301 , having a higher speed, and subsequently scraped by the first roller 201 , 301 by a corresponding scraping member

204, 304.

In such an embodiment, a respective transport conveyor 24 configured to receive the continuous layer "S" laminated by the previous laminating stage 200 and to feed the next laminating stage 300, with the methodologies described above, is comprised between two successive laminating stages. In other words, such transport conveyors have a double function: they receive the laminated material from the previous laminating stage 200 and transport it to the next laminating stage 300. Thereby, such transport conveyors carry out both the role of receiver and feeder in the intermediate parts of the laminating unit 22 and allow a continuous and efficient flow of the material through the various laminating stages 200, 300. Similarly, the last laminating stage 300 can also be associated with a respective transport conveyor arranged immediately downstream.

In the embodiment shown by way of example, the laminating unit 20 comprises a first laminating stage 200 and a second laminating stage 300, however the number of stages can be higher, for example it can preferably be between three and ten. The receiving conveyor 24, arranged downstream of the first laminating stage 200 operates as a transport conveyor to receive the continuous layer "S" laminated by the first laminating stage 200 and to convey it to the second laminating stage 300. The laminating device 20 further comprises, downstream of the second laminating stage 300, a further receiving conveyor 25 configured to receive the continuous layer "S" laminated by the second laminating stage 300 and to transport it, preferably directly, to the drying unit 30.

The rollers 301 , 302 of the second laminating stage 300 operate in accordance with what is described for the rollers 201 , 202 of the first laminating stage 200. In other words, the first roller 301 of the pair of rollers 301 , 302 is rotated at a higher rotation speed than the second roller 302 of the pair of rollers 301 , 302 and the scraping member 304 is adjacent to the first roller 301 and configured to detach the continuous layer "S" from the first roller 301 of the pair of rollers 301 , 302. In other words, the scraping member 304 is associated with the roller 301 operating at a higher speed.

Likewise, the receiving conveyor 25 operates in accordance with what has already been described for the receiving conveyor 24.

In accordance with an aspect of the present invention, the surface of the first roller 201 , 301 and/or the surface of the second roller 202, 302 have a surface structure and/or a surface treatment such as to facilitate a detachment of the continuous layer "S" from the surface of the respective roller 201 , 202, 301 , 302 after the step of compressing.

Advantageously, such a technical feature facilitates the detachment of the continuous layer "S" from the laminating rollers 201 , 202, 301 , 302 and ensures a high quality final product.

In accordance with embodiments not shown, the laminating unit can comprise a train of tangent rollers defining a succession of laminating stages, where each laminating stage shares one of the two rollers with each adjacent stage. In other words, each laminating stage comprises an upstream roller and a downstream roller, defining the through gap of the material therebetween, where the downstream roller of each stage defines the upstream roller of the next stage. In such an embodiment, each laminating stage works in continuity with the previous one. Consequently, the progressive compression of the continuous layer is obtained through a gradual reduction of the through gap between each subsequent pair of rollers, maintaining the continuity of the process. Furthermore, in such an embodiment the continuous layer remains adherent to the rollers of the train of rollers without being detached, unless detached from the last roller of the train of rollers.

Preferably, in such a solution, to facilitate the detachment of the continuous layer, avoiding breakage or delamination of the web in two parts, the last roller of the series of rollers operates at a different speed than the previous roller (the second-to-last roller of the series), and in particular higher. This result is obtained through a control unit connected to the laminating unit, configured to determine the rotation speeds of the rollers. In such a situation, one of the last two rollers of the train of rollers (the one of the two operating at a higher speed) defines the aforesaid first roller, in accordance with what was explained above.

In accordance with a possible variant, in each pair of rollers of the train of rollers, the downstream roller has a different speed from the previous roller and in particular higher, so as to promote (immediately after crossing the respective through gap) the detachment of the material from the upstream roller and adhesion to the downstream roller, thus determining a feeding of the continuous layer without breakage or intermediate delamination.

The present invention achieves the preset objects, suppressing the drawbacks of the prior art.

The lamination is optimal in all its steps and exploits, in particular, the difference in speed between the two laminating rollers of the same pair of rollers in combination with the respective scraping member associated with a roller of the pair of rollers, preferably the faster roller (to which the continuous layer remains adhered). Consequently, the continuous layer "S" is detached in an optimal manner so as to avoid residues and swelling of the machine.

Claims

1 . A method for making a continuous web of reconstituted plant material, comprising the following steps:

- providing a mixture (I) based on at least one reconstituted plant material;

- making a continuous layer (S) with said mixture (I), said continuous layer (S) having a first thickness value;

- feeding said continuous layer (S) to a laminating unit (22) having at least one pair of laminating rollers (201 , 202, 301 , 302);

- subjecting the continuous layer (S), in the laminating unit (22), to at least one step of compressing in a continuous process so as to impart a second thickness value to said continuous layer (S);

- feeding the continuous layer (S) exiting the laminating unit (22) to a drying unit (30), preferably directly, wherein said step of compressing is carried out by said at least one pair of laminating rollers (201 , 202, 301 , 302) by feeding the continuous layer (S) along a feed direction (L); wherein a first of the two rollers (201 , 301 ) of at least one pair of laminating rollers (201 , 202, 301 , 302) is set in rotation at a higher speed than the second roller (202, 302) of the same pair of rollers (201 , 202, 301 , 302) so that the continuous layer (S) adheres to the first roller (201 , 301 ); and wherein the continuous layer (S) exiting the pair of rollers (201 , 202, 301 , 302) is subjected to a scraping action by the first roller (201 , 301 ) by a scraping member (204, 304) cooperating with the first roller (201 , 301 ).

2. The method according to claim 1 , wherein, in said at least one step of compressing, the continuous layer (S) is not subjected to mixing and/or a reduction in particle size.

3. The method according to claim 1 or 2, wherein the continuous layer (S), when entering said at least one pair of rollers (201 , 202, 301 , 302), maintains a substantially planar configuration, and wherein the step of feeding the continuous layer (S) is preferably carried out by supporting the continuous layer (S) by means of a feed conveyor (23), in particular a belt conveyor.

4. The method according to any one of the preceding claims, wherein the continuous layer (S), when it exits the at least one pair of rollers (201 , 202, 301 , 302), and in particular when it is scraped off by the scraping member (204, 304) is released onto a receiving conveyor (24, 25), in particular a belt conveyor, where the continuous layer (S) has a flat shape.

5. The method according to any one of the preceding claims, wherein the laminating unit (22) comprises a plurality of laminating stages (200, 300), disposed in sequence along a feed direction (L) of the continuous layer (S) and each comprising a pair of rollers (201 , 202, 301 , 302) defining a respective through gap (203, 303); the plurality of laminating stages (200, 300) performing a step of compressing the continuous layer (S) in stages so as to progressively reduce the thickness of the continuous layer (S) by means of through gaps (203, 303) of progressively decreasing size; and wherein the continuous layer (S), when it exits each pair of rollers (201 , 202, 301 , 302) is kept adherent to the respective first roller (201 , 301 ), having a higher speed, and is then scraped off the first roller (201 , 301 ) by a corresponding scraping member (204, 304).

6. The method according to claim 5, wherein the first roller (201 , 301 ) of the pair of rollers (201 , 202, 301 , 302) of each laminating stage (200, 300) rotates at a higher speed than the second roller (202, 302) of the same pair of rollers (201 , 202, 301 , 302).

7. The method according to any one of the preceding claims, wherein, in proximity to the pair of rollers (201 , 202, 301 , 302), the feed direction (L) is substantially horizontal, and wherein the first roller (201 , 301 ) of the pair of rollers (201 , 202, 301 , 302) is located under the continuous layer (S).

8. The method according to any one of claims 1 to 6, wherein, in proximity to the pair of rollers (201 , 202, 301 , 302), the feed direction (L) is substantially vertical, and wherein the first roller (201 , 301 ) of the pair of rollers (201 , 202, 301 , 302) is located opposite the roller which the continuous layer (S) remains adherent to when it exits the pair of rollers (201 , 202, 301 , 302).

9. The method according to any one of claims 1 to 4, wherein the laminating unit (22) comprises a plurality of laminating stages disposed in sequence along a feed direction (L) of the continuous layer (S) and is configured as a train of tangent rollers in which a respective through gap for the continuous layer (S) is defined between consecutive tangent rollers so that the continuous layer remains adhered to the rollers between consecutive passage gaps, wherein one of the two rollers of the final laminating stage is rotated at a different speed from the other roller of the final laminating stage so that the continuous layer (S) remains adherent to the roller at a higher speed than the final laminating stage, said roller with a higher speed defining said first roller.

10. The method according to any one of the preceding claims, wherein the ratio between the rotation speed of the first roller (201 , 301 ) and the rotation speed of the second roller (202, 302) is between 1 .01 and 2.5.

11 . The method according to any one of the preceding claims, wherein the surface of the first roller (201 , 301 ) and/or the surface of the second roller (202, 302) has a surface structure and/or a surface treatment such as to facilitate detachment of the continuous layer (S) from the surface of the respective roller (201 , 202, 301 , 302) after the step of compressing.

12. The method according to any one of the preceding claims, wherein the continuous layer (S) exiting the laminating unit has a final thickness corresponding to the thickness of the continuous layer (S) entering the drying unit (30).

13. The method according to any one of the preceding claims, wherein the continuous layer (S) has a moisture content of between 20% and 60%, preferably between 25% and 50% and, still more preferably, between 27% and 40%.

14. The method according to any one of the preceding claims, wherein the first roller (201 , 301 ) of the pair of rollers (201 , 202, 301 , 302) is the bottom roller (201 , 301 ) of the pair of rollers (201 , 202, 301 , 302).

15. A device (20) for laminating a continuous layer (S) of reconstituted plant material, comprising:

- feed means (21 ) for feeding a continuous layer (S) of a mixture (I) containing reconstituted material, configured to convey the continuous layer (S) along a feed direction (L);

- a laminating unit (22), equipped with at least a first laminating stage (200,

300), said at least a first laminating stage (200, 300) comprising at least one pair of laminating rollers (201 , 202, 301 , 302) defining a through gap (204, 304) between them and configured to vary the thickness of the continuous layer (S) when the continuous layer (S) passes between the rollers (201 , 202, 301 , 302);

- a control unit connected to the laminating unit (22) and configured to set the first roller (201 , 301 ) of the at least one pair of rollers (201 , 202, 301 , 302) in rotation at a higher rotation speed than the second roller (202, 302) of the pair of rollers (201 , 202, 301 , 302); and wherein said at least one laminating stage (200, 300) comprises a scraping member (204, 304) adjacent to the first roller (201 , 301 ) and configured to detach the continuous layer (S) from the first roller (201 ,

301 ).

16. The device (20) according to claim 15, wherein the feed means (21 ) comprise a feed conveyor (23), in particular a belt conveyor, located immediately upstream of said first laminating stage (200) and configured to feed the continuous layer (S) to said first laminating stage (200); said feed conveyor (23) being configured to cooperate with said pair of rollers (201 , 202) to feed the continuous layer (S) to the first laminating stage (200) in a substantially planar configuration and in particular, a substantially horizontal or substantially vertical configuration.

17. The device (20) according to claim 15 or 16, wherein, in proximity to the pair of rollers (201 , 202, 301 , 302), the feed direction (L) of the continuous layer (S) is horizontal, and wherein the first roller (201 , 301 ) of the pair of rollers (201 , 202, 301 , 302) is located under the continuous layer (S).

18. The device (20) according to claim 15 or 16, wherein, in proximity to the pair of rollers (201 , 202, 301 , 302), the feed direction (L) of the continuous layer (S) is vertical, and wherein the first roller (201 , 301 ) of the pair of rollers (201 , 202, 301 , 302) is located opposite the roller which the continuous layer (S) remains adherent to when it exits the pair of rollers (201 , 202, 301 , 302).

19. The device (20) according to any one of claims 15 to 18, comprising a receiving conveyor (24), in particular a belt conveyor, located downstream of said first laminating stage (200), and wherein:

- the feed conveyor (23) is configured to feed the continuous layer (S) to the first laminating stage (200) in a substantially horizontal configuration and the scraping member (204) is associated with the first roller (201 ) of said first laminating stage (200) to release the continuous laminated layer (S) in a substantially planar configuration onto the receiving conveyor (24); or

- the feed conveyor (23) is configured to feed the continuous layer (S) to the first laminating stage (200) in a substantially vertical configuration and the scraping member (204) is associated with the second roller (201 ) of said first laminating stage (200) to release the continuous laminated layer (S) in a substantially planar configuration onto the receiving conveyor (24).

20. The device (20) according to any one of claims 15 to 19, wherein the laminating unit (22) comprises a plurality of laminating stages (200, 300), disposed in sequence along a feed direction (L) of the continuous layer (S) and each comprising a pair of rollers (201 , 202, 301 , 302); the plurality of laminating stages (200, 300) being configured to compress the continuous layer (S) progressively so as to progressively reduce the thickness of the continuous layer (S) by means of respective through gaps (204, 304) of progressively decreasing size; and wherein each laminating stage (200, 300) further comprises a respective scraping member (204, 304) adjacent to the first roller (201 , 301 ) of the corresponding laminating stage (200, 300) and configured to detach the continuous layer (S) from the respective first roller (201 , 301 ).

21. The device (20) according to claim 20, wherein the first roller (201 , 301 ) of the pair of rollers (201 , 202, 301 , 302) of each laminating stage (200, 300) rotates at a higher speed than the second roller (202, 302) of the same pair of rollers (201 , 202, 301 , 302).

22. The device (20) according to any one of claims 15 to 21 , wherein the ratio between the rotation speed of the first roller (201 , 301 ) and the rotation speed of the second roller (202, 302) is between 1 .01 and 2.5.

23. The device (20) according to any one of claims 15 to 22, wherein the surface of the first roller (201 , 301 ) and/or the surface of the second roller (202, 302) has a surface structure and/or a surface treatment such as to facilitate detachment of the continuous layer (S) from the surface of the respective roller (201 , 202, 301 , 302) after the step of compressing.

24. The device (20) according to any one of claims 15 to 23, wherein the laminating unit (22) is configured as a train of tangent rollers in which a respective through gap for the continuous layer (S) is defined between consecutive tangent rollers, which defines a respective laminating stage, the last two rollers of the train of rollers defining a final laminating stage, and wherein one of the two rollers of the final laminating stage is rotated at a different speed than the other roller of the final laminating stage so that the continuous layer (S) remains adherent to the roller at a higher speed of the final laminating stage, said roller at a higher speed defining said first roller.

25. A machine (1 ) for making a continuous web of reconstituted plant material, comprising:

- a device (10) for preparing a mixture (I) based on reconstituted plant material;

- a laminating device (20) according to any one of claims 15 to 24, located downstream of the device (10) for preparing the mixture (I); and

- a drying unit (30) located preferably directly downstream of the laminating unit (22), and in particular downstream of the last laminating stage (300) of the laminating unit (20) along said feed direction (L).